United States Office of Water and SW 176C.13
Environmental Protection Waste Management October 1979
Agency Washington, D.C. 20460
Solid Waste
vvEPA European Refuse Fired
Energy Systems
Evaluation of Design Practices
Volume 13
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pJie.pu.bt4.cot-con -cA4ue (Jot EPA t<
and Solid Sotid (Ua&te Mana.ge.me.nt
EUROPEAN REFUSE FIRED ENERGY SYSTEMS
EVALUATION OF DESIGN PRACTICES
Copenhagen:
West Denmark
(SW-176c.I3) de4c.tx.be6
the 0^-ic.e. 0(J Sotid WaAte. undeA c.ontA.ac.t no. 6S-01-4376
and u> fLe.piodace.d OA icce,ived ^nom tke. c.ontMi
-------
This report was prepared by Battelle Laboratories, Columbus, Ohio,
under contract no. 68-01-4376.
Publication does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of commercial products constitute endorsement by the U.S.
Government.
An environmental protection publication (SW--176c.l3) in the solid waste
management series.
L,S. Environmental Protection
-------
TRIP REPORT
to
COPENHAGEN: WEST, DENMARK
on the contract
EVALUATION OF EUROPEAN REFUSE-
FIRED ENERGY SYSTEM DESIGN PRACTICES
in October, 1977
to
U.S. ENVIRONMENTAL PROTECTION AGENCY
February 15, 1978
EPA Contract No. 68-01-4376
RFP No. WA-76-B146
by
Philip R. Beltz and Richard B. Engdahl
BATTELLF.
Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201
-------
i
PREFACE
This trip report is one of a series of 15 trip reports on
European waste-to-energy systems prepared for the U.S. Environmental
Protection Agency. The overall objective of this investigation is to
describe and analyze European plants in such ways that the essential
factors in their successful operation can be interpreted and applied
in various U.S. communities. The plants visited are considered from
the standpoint of environment, economics and technology.
The material in this report has been carefully reviewed by the
European grate or boiler manufacturers and respective American licensees.
Nevertheless, Battelle Columbus Laboratories maintains ultimate responsi-
bility for the report content. The opinions set forth in this report are
those of the Battelle staff members and are not to be considered by EPA
policy.
The intent of the report is to provide decision making in-
formation. The reader is thus cautioned against believing that there is
enough information to design a system. Some proprietary information has
been deleted at the request of vendors. While the contents are detailed,
they represent only the tip of the iceberg of knowledge necessary to de-
velop a reliable, economical and environmentally beneficial system.
The selection of particular plants to visit was made by Battelle,
the American licensees, the European grate manufacturers, and EPA. Pur-
posely, the sampling is skewed to the "better" plants that are models of
what the parties would like to develop in America. Some plants were selected
because many features envolved at that plant. Others were chosen because
of strong American interest in co-disposal of refuse and sewage sludge.
The four volumes plus the trip reports for the 15 European
plants are available through The National Technical Information Service,
Springfield, Virginia 22161. NTIS numbers for the volumes and ordering
information are contained in the back of this publication. Of the 19
volumes only the Executive Summary and Inventory have been prepared for
wide distribution.
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ii
ORGANIZATION
The four volumes and 15 trip reports are organized the the
following fashion:
VOLUME I
A EXECUTIVE SUMMARY
B INVENTORY OF WASTE-TO-ENERGY PLANTS
C DESCRIPTION OF COMMUNITIES VISITED
D SEPARABLE WASTE STREAMS
E REFUSE COLLECTION AND TRANSFER STATIONS
F COMPOSITION OF REFUSE
G HEATING VALUE OF REFUSE
H REFUSE GENERATION AND BURNING RATES PER PERSON
I DEVELOPMENT OF VISITED SYSTEMS
VOLUME II
J TOTAL OPERATING SYSTEM RESULTS
K ENERGY UTILIZATION
L ECONOMICS AND FINANCE
M OWNERSHIP, ORGANIZATION, 'PERSONNEL AND TRAINING
VOLUME III
P REFUSE HANDLING
Q GRATES AND PRIMARY AIR
R ASH HANDLING AND RECOVERY
S FURNACE WALL
T SECONDARY (OVERFIRE) AIR
VOLUME IV
U BOILERS
V SUPPLEMENTARY CO-FIRING WITH OIL, WASTE OIL AND SOLVENTS
W CO-DISPOSAL OF REFUSE AND SEWAGE SLUDGE
X AIR POLLUTION CONTROL
Y START-UP AND SHUT-DOWN
Z APPENDIX
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TABLE OF CONTENTS
Page
LIST OF PERSONS CONTACTED OR REFERENCED 1
STATISTICAL SUMMARY 2
OVERALL SYSTEM SCHEMATIC 14
COMMUNITY DESCRIPTION ^
Geography 14
SOLID WASTE PRACTICES 19
Solid Waste Generation -^g
Solid Waste Collection 19
Solid Waste Transfer 23
Recycling 23
Solid Waste Disposal 23
DEVELOPMENT OF THE SYSTEM 25
Volund's Relation to the North American Market 33
Volunu's Preferred Procedure for System Start-Up 34
PLANT ARCHITECTURE AND AESTHETIC ACCEPTABILITY 35
TOTAL OPERATING SYSTEM 45
REFUSE-FIRED HOT WATER GENERATOR EQUIPMENT 50
Waste Input 50
Weighing Operation 50
Provisions to Handle Bulky Wastes 55
Waste Storage and Retrieval 56
Furnace Hoppers, Feeders, and Swivel Gate 58
Primary (Underf ire) Air 59 '
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TABLE OF CONTENTS
(Continued)
Page
Secondary (Overflre) Air - Boiler Room Cool Air 63
Secondary (Overfire) Air - Flue Gas Recirculation Hot Air .... 63
Flue Gas Fan 65
Fan Summary 66
Furnace Combustion Chamber 66
Burning Grate (Forward Pushing Step Grate) 69
Furnace Refractory Wall 74 .
Rotary Kiln 78
After Burning Chamber 85
Boiler (General) 85
Economizer 89
Boiler Water Treatment 92
ENERGY UTILIZATION EQUIPMENT 93
Comments on Heat Exploitation 96
POLLUTION CONTROL EQUIPMENT 105
ENVIRONMENTAL AND ENERGY CONSERVATION ASSESSMENT 108
ASH HANDLING AND PROCESSING 112
ASH RECOVERY 118
Background 118
Quantities 118
Flyash 119
Road Test Procedures 119
-------
TABLE OF CONTENTS
(Continued)
Parking Lot and Road Test Results ................ 122
Environmental Tests - General .................. 123
Environmental Test Results - General ............... 123
Liquid Percolate (Leachate) , Fresh Water, Sea Water,
and Drinking Water ....................... 124
Tests and Results - Unprocessed Cinders at Special
Sanitary Landfill ....................... 124
Solid Processed Cinder and Soil Comparative Tests ........ 127
Test on Parking Lot in Ballerup ................. 127
Cinders as Excellent Landfill Cover Material ........... 131
CHIMNEY ................................ 132
ORGANIZATION, PERSONNEL AND TRAINING ................ 133
Personnel ............................ 136
Education and Experience ..................... 138
Training ........................... 138
ECONOMICS ............................. „ . 140
Capital Cost ........................... 140
Annual Cost ........................... 140
Profitableness at Exploitation of Heat .............. 144
FINANCE ................................ 148
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LIST OF TABLES
Page
Table 15-1. Population and Refuse Consumption in the Copenhagen
Immediate Metropolitan Area 20
Table 15-2. Refuse Analysis for West Incinerator of Copenhagen 22
Table 15-3. Inhabitant and Quantities of Refuse for Combustion 30
Table 15-4. Primary, Secondary, Flue Gas and Recirculation Fan
Parameters 67
Table 15-5. Analytical Values of Trace Elements in the Percolate .... 125
Table 15-6. Element Composition of Soil and Cinders (All Analyses Are
Made on Dry Material) 128
Table 15-7. Comparison of Analyses of Percolate from Depot 1 in
Vestskoven and Percolate, Drain Water, and Surface Run-Off
from Parking Lot in Ballerup 130
Table 15-8. Capital Cost (Assets and Liabilities) at Copenhagen: West
(Fiscal Year 1975-1976) 141
Table 15-9. Expense and Revenue Blalance at Copenhagen: West 142
Table 15-10. Operational Costs (Exclusive of Interest and Depreciation)
and Income by Heat Sale from a Plant with Three Furnaces
12 t/h for Variable Net Calorific Values of Refuse and
Degree of Incineration Capacity 146
Table 15-11. Operational Costs (Exclusive of Interest and Depreciation) and
and Income by Heat Sale from a Plant with Two Furnaces
of 3 t/h for Variable Net Calorific Values of Refuse and
Degree of Incineration Capacity 147
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LIST OF FIGURES
Page
Figure 15-1. Side and Overviews of Copenhagen: West Refuse-
Fired Steam Generator 15
Figure 15-2. Cross-Sectional Engineering Drawing of Copenhagen:
West RFSG 16
Figure 15-3. Map of Greater Copenhagen Area Showing the Location of
the West (Vest) Refuse Fired Steam Generator, The
Hillerod Transfer Station, Volund Headquarters, Etc ... 17
Figure 15-4. Detailed Map Showing Location of West Plant at the
Intersection of Two Major Highways 18
Figure 15-5. Communities Proportion of Refuse Input to Copenhagen:
West RFSG 21
Figure 15-6. Upper Portion of Transfer Station at Hillerod 24
Figure 15-7. Source Separation Truck Discharging Separated Items into
Recycling Bins Before Scales and Tipping Floor at
Copenhagen: West 24
Figure 15-8. First Volund System Built at Gentofte in 1932 and
Decomissioned 40 Years Later in 1972 26
Figure 15-9. Long-Range Planning of Furnace Additions 31
Figure 15-10. Total Environmental and Some Energy Program at Copenhagen:
West 32
Figure 15-11. Volund's Procedure for System Development 35
Figure 15-12. Swans in Pond on Property of Copenhagen: West 37
Figure 15-13- Architects Overheat Plan for Landscaping at Copenhagen:
West 38
Figure 15-14. Aerial Photograph of Copenhagen: West and its Surroundings. 40
Figure 15-15. Exterior Wall Architecture Theme at Copenhagen: West. ... 41
Figure 15-16. Cross-Sectional Schematic of Copenhagen: West RFSG 42
*
Figure 15-17. Spacious Conference Room at Copenhagen: West 43
Figure 15-18. Comfortable and Pleasant Lounge Area Control Room at
Copenhagen: West 44
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LIST OF FIGURES
(Continued)
Page
Figure 15-19. Maximum Rated Capacity on Volund Rotary Kiln Furnaces. . 46
Figure 15-20. Source Separation Recycling Station at Copenhagen:
West 51
Figure 15-21. Modular Unit Layout at Copenhagen: West 52
Figure 15-22. Truck Driver Inserting Plastic Card to Activate Scale,
Computer Calculation, Television Display and Permanent
Record at Copenhagen: West 53
Figure 15-23. Scale House Control Panel with Television Monitors of
Tipping Floor and Computer Printout of Weighing Information
at Copenhagen: West 54
Figure 15-24. The Two Crane Operators in the Crane Control Room at
Copenhagen: West 57
Figure 15-25. Warped Feed Chute at Copenhagen: West 60
Figure 15-26. Peeled Paint on Feed Chute Caused by Burnback. Also
Primary Air Fan at Copenhagen: West 61
Figure 15-27. Sloping Air Intake Filters Above the Bunker at
Copenhagen: West 62
Figure 15-28. Rotary Kiln and Flue Gas Recirculation Duct at
Copenhagen: West 64
Figure 15-29. General Design Configurations for Volund Furnaces. ... 68
Figure 15-30. Furnace Design (Two-Way Gas Grate and Rotary Kiln) at the
Old (1934) Frederiksberg Plant, Now Dismantled .... 70
Figure 15-31- Volund's Forward Pushing Step Grate 71
Figure 15-32. Volund Grate Bars on Display 72
Figure 15-33. Grate Furnace Exit into a Rotary Kiln at one of Volund's
Plants 75
Figure 15-34. Broken Away Section and Slag on Walls at Copenhagen:
West 77
Figure 15-35. Picture of the Volund Rotary Kiln 80
Figure 15-36. Control Room Panel Featuring Television View of Rotary
Kiln at Copenhagen: West 81
Figure 15-37. Water-Cooled Closed Circuit Television Camera Looking at
the Rotary Kiln Fire 82
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LIST OF FIGURES
(Continued)
Page
Figure 15-38. View into Rotary Kiln Taken from Lower End. See
Discharge from Grate Furnace, at Copenhagen: West. ... 83
Figure 15-39. Virtually Smokeless Burn in Volund Rotary Kiln at
Itabashi, Japan 84
Figure 15-40. Volund Boiler Schematic at Copenhagen: West 88
Figure 15-41. Vibrating Conveyor for Steel Shot Used in Boiler Cleaning
at Copenhagen: West 90
Figure 15-42. Steel Shot Hopper Above the Boiler at Copenhagen: West . . 91
Figure 15-43. Map Showing District Heating Customers 94
Figure 15-44. District Heating System at Copenhagen: West 95
Figure 15-45. Actual Distribution of Heat: Production and consumption at
West During 1976/77 97
Figure 15-46. Potential Distribution of Heat: Production and Consumption
at West 1984/85 98
Figure 15-47. District Heating Pipe Tunnel at Copenhagen: West 99
Figure 15-48. Tonnes of Oil per Month or Equivalent Energy in Refuse . . 102
Figure 15-49. District Heating Plan as of 1976/77 for Copenhagen: West . 103
Figure 15-50. District Heating Plan as of 1984/85 for Copenhagen: West . 104
Figure 15-51. Looking out the Windows Taken from Under the Electrostatic
Precipitators at Copenhagen: West 106
Figure 15-52. Refuse Volume Reduction as a Function of Various Treat-
ment Methods 109
Figure 15-53. Schematic Showing How a Central District Heating Apartment
System Compares in Efficiency with Individual Home Heating
Systems Ill
Figure 15-54. Skip Hoist Dumping Incinerator Ash (SLAG) at Copenhagen:
West 113
Figure 15-55. Ash Handling and Processing at Copenhagen: West 114
Figure 15-56. Ash Recovery at Copenhagen: West 115
Figure 15-57. Vibrating Machinery for Ash Processing at Copenhagen:
West 116
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LIST OF FIGURES
(Continued)
Figure 15-59. Mountain of Processed Ash Residue Awaiting Use for Road-
building or Cinder Block Manufacture at Copenhagen: West. 117
Figure 15-60. The Variation Interval for the 16 mm Fraction of Graded
Cinders Before (solid line) and After (dotted line)
Compacting by Field Tests 120
Figure 15-61. Annual General Meeting Participants 134
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LIST OF PERSONS CONTACTED, REFERENCED. OR CONSTRUCTION PARTICIPANTS
Gabriel Silva Pinto
M. Rasmussen
Mr. G. Balsten
Project Manager, Main Plant Layout, Volund
Chief Engineer, Sales Activities Volund
Director of Copenhagen: West
K. Jensleu
Thomas Rosenberg
Civil Engineer
Sales Manager, International Incinerators, Inc.,
Atlanta, Georgia
Addresses
Refuse Fired Hot Water Generation Plant
I/S Vestforbraending, Ejbymosevej 219
2600 Glostrup, Denmark
Vendor Headquarters
A/S Volund
11 Abildager
2600 Glostrup
Denmark
Tele: 02-452200
Telex: 33130 Volund Dk
WEKA-VERLAG Gmbh
8901 Kissing
Augsburgerstrasse 5
Germany
American Coordinating Firnt
Volund USA Ltd.
Mr. Gunnar Kjaer, President
900 Jorie Boulevard
Oak Brook, Illinois 60521
Tele: (312) 655-1490
*This firm is owned by:
1. Volund A/S (Denmark)
2. Waste Management, Inc.
3. Jack Lyon & Assoc.
American Sales Representative
Mr. Ronald Heverin
Director of Marketing
Advanced Systems Group
Waste Management, Inc.
900 Jorie Boulevard
Oak Brook, Illinois 60521
Tele: (312) 654-8800
Danish Boiler Association
Dansk kedel Forening
Sankt Pedersvej 8
2900 Hellerup Denmark
Tele: (01)629211
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STATISTICAL SUMMARY
GENERAL
Name of plant
Location of plant
Year completed
Administrator
Space of plant
Space of building
Cost of construction
including a building
DESIGN DATA
Plant capacity
Capacity, each furnace
Number of furnace
Operating
Stand-by
Extension
Calorific value of refuse
Lowest
Average
Highest
Composition of refuse
Combustibles
Ash & Inerts
Water
Furnace temperature
Minimum
Average
Maximum
Contents of unburnt matter in residue
Vest Plant (West Plant)
Copenhagen, Denmark
1970
Communities of interest consist of several
municipalities including parts of Copenhagen
,2
approx. 120,000 m2
approx. 10,600 m
approx. 140,000,000 D.kr.
864 tonnes/24h
Increased to 1152 in 1977 by
addition of Furnace #4
288 tonnes/24h
3
0
1000 kcal/kg
2000 kcal/kg
2500 kcal/kg
Lowest Average Highest
26% 45% 55%
42% 26% 22%
32% 29% 23%
850° C
950° C
1000° C
0-3%
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STATISTICAL SUMMARY (Cont.)
OPERATION OF PLANT
Amount of refuse incinerated
Cost of operation
Number of operators and workers
Number of officers
Operating hours of plant
Working hours of operators
Number of shifts
Electric power consumption
Water consumption
Actual continuous operating time
Actual operating days
Maintenance and repair of plant
Regular or periodical overhaul & repair
including mechanic, electric, and
boiler systems
220,000 - 330,000 tonnes/year
D.Kr. 30/tonne of refuse
45
10
24 hours/day 7 days/week
8 hours/day 5 days/week
6
1,000,000 KwH/month
8,000 tonnes/month
approx. 12 weeks
365 days/year
normal
REFUSE COLLECTION AND TRANSPORTATION
Population in refuse collection
region of the plant
Area of refuse collection of the plant
Amount of refuse collected, presently
Disposal of refuse
Incineration
Dumping at sea
Reclamation
Others (dump) industrial refuse
Method of transportation
650,000
325 km2
1400 - 2000 tonnes/day
50%
50%
truck
-------
STATISTICAL SUMMARY (Cent.)
Size of trucks
Carrying capacity
Charge of collection
refuse trans. 2-8 tonnes
ash trans. 5-15 tonnes
charged 30 D.Kr/t.
REFUSE STORING
Weighing equipment of refuse
Number
Type
Capacity
Recording, printing, and
summation of weight
Refuse silo (bunker)
Number
Capacity
Dimension
Length
Width
Depth
Specific weight of refuse
Storing capacity
Refuse silo door
Type
Number
Dimension
Height
Width
Thickness, total
automatic
50 tonnes
automatic
12,500 m
56 m
17 m
13.5,0 m
3
0.2 - 0.3 tonnes/m
A days max. refuse delivery
Flap, double-hinged
12
8.0 m
3.8 m
122 mm
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STATISTICAL SUMMARY (Cont.)
Operation
Oozed water pit
Capacity
Big refuse crusher
Number
Type
Capacity
Location
Operation
Refuse feeding
hydraulic
13,000 m3
2 (in 1970 and 1975)
Lindemann
80 m3/h
Between unloading and refuse pits
hydraulic
Dumping from truck
FURNACE
Filling hopper
Number
Clear opening at top
Clear opening at bottom
Height
Thickness of plate
Materials
Volume
Filling chute
Number
Clear opening
Height
Thickness of plate
Volume
Swivel gate in filling chute (damper)
Number
Dimension
Thickness
Operation
1 per furnace
6500 mm x 6500 mm
2300 mm x 1150 mm
5900 mm
O IPOT1
Mild steel
15 m3
2350 mm x 1150 mm
7000 mm
8 mm
19 m3
2300/2700 mm x 1260 mm
10 mm
manual
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STATISTICAL SUMMARY (Cant.)
GRATES
Grate I
Width of grate
Length of grate
Area
Velocity of grate
Length of grate stroke
Type of grate
Materials of grate
Grate frame
Grate bar or plate
Side seal
Grate II
Width of grate
Length of grate
Area
Velocity of grate
Length of grate stroke
Type of grate
Materials of grate
Grate frame
Grate III
Width of grate
Length of grate
Area
Velocity of grate
Length of grate stroke
Type of grate
Materials of grate
Grate frame
Grate bar or plate
Side seal
Grate IV (None)
2700 mm
2500 mm
6.75 m2
3 stroke/min.
130 mm
grate bar, grate plate
Meehanite HR
Meehanite HR
Nicromax
2700 mm
2000 mm
5.4 m2
3 stroke/min.
130 mm
grate bar
Meehanite HR
2700 mm
5000 mm
13.5 m2
3 stroke/min.
130 mm
grate bar, grate plate
Meehanite HR
Meehanite HR
Nicromax
-------
STATISTICAL SUMMARY (Cont.)
Rotary kiln
Shape cylindrical
Diameter
Inside of shell 4000 mm
Inside of lining 3400 mm
Length 8000 mm
Volume 73 m
Number of revolutions 0-12 rph
Inclination 3 deg.
Materials of shell Carbon steel
Materials of support ring High tensile strength steel castings
Materials of support roller High tensile strength steel castings
Materials of thrust roller High tensile strength steel castings
Number of support ring 2
Number of support roller 2
Number of thrust roller 1
Number of drive support roller 2
Steps between grates
Number of steps - 2
Height of steps between
Grate I and Grate II 1.0 m
Height of steps between
Grate II and Grate III 2.0 m
Steps between grate and rotary kiln
Number of steps 1
Height of steps 1.0 m
Width of steps 2.7 m
Hopper under grate
Number 4
Thickness of plate 6 mm
Size of chute 240 x 240 mm
-------
STATISTICAL SUMMARY (Cont.)
900 mm x 1000 mm
1900 mm
1 set/furnace
operating 2, stand-by 0
47 lit/min. each pump
Clinker chute
Clear opening
Height
After combustion chamber
Volume 125 m
Hydraulic equipment for grate movement and rotary kiln
Number per furnace
Hydraulic pump
Number per furnace
Capacity
Pressure
Motor
Oil tank
Hydraulic cylinder
Number
Cylinder bore
Cylinder stroke
Hydraulic motor for rotary kiln
Number per kiln
Revolution
Torque
Speed reduction equipment
Type
Number per kiln
Revolution
Torque
Ratio of reduction
Grate I
5
80 mm
130 mm
75 kg/ cm g
15 HP each
600 liters
Grate II Grate III
5 5
80 mm 80 mm
130 mm 130 mm
max. 1200 rpm
3 kg-m
Double Worm gear
2
max. 76 rph
1272 kg-m
1:800
VENTILATING AND DRAFTING PLANT
Primary air fan (P. D. Fan)
Manufacturer
Number per furnace
Nordisk Ventilator
1
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STATISTICAL SUMMARY (Cont.)
Amount of air
Static pressure
Temperature
Number of revolutions
Driving
Motor
Secondary air fan (Cooling air fan)
Number per furnace
Amount of air
Static pressure
Temperature
Number of revolutions
Driving
Motor
Flue gas fan (I.D. Fan)
Number per furnace
Amount of gas
Static pressure
Temperature
Number of revolutions
Driving
Motor
Re-circulation fan
Number pei furnace
Amount of air
Static pressure
Temperature
Number of revolutions
Driving
Motor
45,000 Ntn /h
230 moAq
30° C
1490 rpm
belt drive
75 HP
35,000 NmJ/h
460 mmAq
30° C
1670 rpm
belt drive
150 HP
107,000 Nm /h
172 mmAq
350° C
1010 rpm
belt drive
220 HP
45,000 Nni/h
220 mmAq
350° C
1460 rpm
belt drive
150 HP
-------
10
STATISTICAL SUMMARY (Cent.)
CHIMNEY
Chimney
Type
Number
Diameter at top
Height
Gas velocity at top
Concrete with steel flue
1 per 4 furnaces
220 mm
150 m
max. 27 m/sec
Auxiliary Burning Plant for Furnace (None)
DUST COLLECTION PLANT
Electrostatic precipitator
Number per furnace
Capacity
Gas temperature
Operating
Maximum
Dust content
Inlet
Outlet
Efficiency
Pressure drop
Multi-cyclone (None)
107,000 Nm /h
300° C
350° C
7.5 g/Nra3
0.15 g/Nm3
98%
5-10 mmAq
CLINKER AND FLY ASH TRANSPORTATION PLANT
Clinker transportation equipment under clinker chute
Type Clinker Sluice skip-hoist
Number per furnace 1
Capacity 4 tonnes/h
Speed 7.8 m/min
Length of traveling H m
-------
11
STATISTICAL SUMMARY (Cont.)
Ash transportation equipment under grates and rotary kiln
Type vibration conveyor
Number per furnace 1
Capacity 0.6 tonnes/h
Speed .6 - 1.2 m/min
Width diam. 300 mm
Length 16 m
Ash transportation equipment under boiler or gas cooler
Type vibration conveyor
Number per furnace 1
Capacity 0.6 tonnes/h
Speed .6 - 1.2 m/min
Width diam. 300 mm
Length 8 m
Fly ash transportation equipment under dust collector
Type (fluidizing)
Number per furnace 4
Capacity 0.6 tonnes/h
Clinker silo
Capacity 1200 m
Dimension
Length 47 m
Width 5.2 m
Depth 5 m
Specific weight of clinker 1.0 tonnes/m
Storing capacity 4 days
Clinker crane
Number operating 1 stand-by 1
Type of grab Clam shell grab
Operation of grab wire rope, hydraulic
Volume of grab 2.5 m
Weight of clinker held 2.0 tonnes
Weight of grab 2.1 tonnes
-------
12
STATISTICAL SUMMARY (Cont.)
Weight of hoisting
Span
Length of traveling
Height of hoisting
Hoisting velocity
Traveling velocity
Traversing velocity
Hoisting motor
Traveling motor
Traversing motor
Power supply system
Disposal of clinker and fly ash
GAS COOLING PLANT (BOILER)
Method of gas cooling
Boiler
Type
Number per furnace
Design pressure
Working pressure
Steam or hot water temperature
Feed water temperature
Capacity
Heating surface (Units 1-3)
Radiation heating surface
Convection heating surface
Superheater (None)
Economizer
Gas air heater (None)
Gas temperature
Inlet
Outlet
4.1 tonnes
9,630 mm
48 m
12 m
45 m/min
50 m/min
30 m/min
48 KW
2 x 2.5 KW
1.6 KW
Cable for main switch flexible hanging cable
landfill
waste heat boiler
hot water boiler water tube
1
2
25 kg/cm g
16 kg/cm g
170° C
140° C
20 x 106 kcal/h
330 m2
330 m2
300 m2
800° C
280 - 320° C
-------
13
STATISTICAL SUMMARY (Cont.)
Amount of gas
3
Lowest calorific value 33,000 Nm /h
Average calorific value 77,000 Nm /h
Highest calorific value 98,500 Nm /h
Boiler outlet gas temperature control yes, automatic
Heat utilization district heating
Water spray gas cooler (None)
Boiler cleaning equipment
Type shot cleaning
Soot blower (None)
Hot water cooler
Type air cooler
Number 1
Heat exchanged 50 x 10 kcal/h
2
Steam or hot water pressure 16 kg/cm g
Steam or hot water temperature
Inlet 170° C
Outlet 120° C
-------
14
OVERALL SYSTEM SCHEMATIC
Several schematics are presented. Figure 15-1 shows the cross-
sectional schematic and the overhead view. A more precise engineering
drawing is shown in Figure 15-2.
COMMUNITY DESCRIPTION
Geography
Figure 15-3 is a map of the Copenhagen metropolitan area.
Copenhagen itself is located on the east coast of Denmark, not far from
Sweden.
The West (Vest) refuse fired steam generator (Vestforbranding)
is shown along with its twin unit on the Amager Island just southeast of
downtown Copenhagen.
The terrain is rather flat, which is typical of eastern Denmark.
There are no particular geographical features that impacted plant con-
struction. The primary site location consideration was to be at the
intersection of two main highways as shown in Figure 15-4.
The population in the City of Copenhagen proper has fallen from
550,000, ten years ago, to 430,000 presently. Reasons are typical of those
in many large cities. Basically young families are moving to the suburbs,
leaving the City for students, government workers, retired people, and
those wishing a short commute to work. The West plant serves about 620,000
people in western Copenhagen and eleven of its western and northern suburbs.
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15
1. Opmarchplads
2. Vaegt
3. Vaegthus
4. Aflaesningshal
5. Knuser
6. Affaldssilo
7. Ovnhal
8. Slaggesilo
9. Rogkanal
10. Kontrolrum
H.Maskinsal
12. Trappetarn
13. Administration,
1. Arrival
2. Weighbrdge
3. Weighing-station
4. Unloading
5. Crushing-mill
6. Refuse-pit
folkerum, vaerksteder 7. Incineration-hall
8. Ash-pit
9. Flue
10. Central control room
11. Pump-room
12. Staircase
13. Administration, staff-tract,
workshops
FIGURE 15- 1. SIDE AND OVERVIEWS OF COPENHAGEN: WEST REFUSE-
FIRED STEAM GENERATOR
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16
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17
•Landfill
Transfer Station
FIGURE 15-3.
Volund Headquarters
MAP OF GREATER COPENHAGEN AREA SHOWING THE
LOCATION OF THE WEST (VEST) REFUSE FIRED
STEAM GENERATOR, THE HILLER0D TRANSFER
STATION, VOLUND HEADQUARTERS, ETC.
15 miles
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18
FIGURE 15- 4 .
DETAILED MAP SHOWING LOCATION OF WEST PLANT
AT THE INTERSECTION OF TWO MAJOR HIGHWAYS
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19
SOLID WASTE PRACTICES
Solid Waste Generation
The immediate Copenhagen metropolitan area, as served by the two
large Volund plants (Amager and West), has a total population of 1,137,978
and generates 509,246 tonnes (560,171 tons) per year as shown in Table 15-1,
Twelve (12) communities (Figure 15-5) sent 255,807 tonnes
(281,388 tons) to Copenhagen: West during the 1975/76 fiscal year. On a
seven (7) day burning basis, about 479 tonnes (527 tons) per day were con-
sumed. These figures compare with the rated capacity of 864 tonnes (950
tons).
Each person generates about 500 kg (1100 pounds) per year.
In summary, the refuse composition has been changing over the
years to about these figures:
1964/65 1970 1977
Heat Value (kcal/kg) 1,600 1,800 - 2,000 2,200
Moisture (%) 35 33 28
Combustibles (%) 40 45 49
Non-Combustibles (%) 25 22 23
Many years ago, 1964 and 1965, an extensive analysis was conducted over
many months, seasons, weather conditions, and refuse generation sources.
The results are summarized for April 1964 and January 1965. While the
data is old, perhaps it will be useful. (See Table 15-2.)
Solid Waste Collection
In addition to the normal input from local garbage trucks, large
transfer trailers from Hillerod travel about 40 km (25 miles) one-way to
bring northern waste to the Copenhagen: West unit. Additional comments
on collection activities are presented in the Copenhagen: Amager Trip
Report 14.
The overall cost for collection and disposal averages about
420 D.kr. ($72.69) per year per person in Denmark.
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20
TABLE 15-1. POPULATION AND REFUSE CONSUMPTION
IN THE COPENHAGEN IMMEDIATE
METROPOLITAN AREA
Population (inhabitants) April 1, 1974
I/S Amager Area
*
I/S Vest Area
Refuse Consumption (tonnes)
I/S Amager Plant
I/S Vest Plant
524,955
581,333
1,106,288
1974-75
224,449
215,224
439,673
April 1, 1975
580,556
575,996
1,156,552
1975-76
255,488
234,230
489,718
April 1, 1976
568,343
569,635
1,137,978
1976-77
255,807
' 253,439
509,246
*
Vest is translated to West
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22
TABLE 15-2. REFUSE ANALYSIS FOR WEST INCINERATOR OF COPENHAGEN
Average Refuse Compos itio
1. Shoping Area
2. Villa Housing Area
3. New Housing Area
4. Industrial Area
Total Average on Serie 1
i - Serie I Date: April 6-9, 1964
%
10
34
27
29
100
Moist.
2.96
10.06
7.73
10.35
31.10
Comb.
4.54
14.68
12.47
9.27
40,96
Ash
2.50
9.25
6.80
9.39
27,94
Volatiles
3.88
11.24
10.83
7.69
33.64
Fixed
c
0.65
3.45
1.64
l.,58
7.32
Hi
keal/kg
186.40
528.76
485.73
366.56
1621,43
Average refuse composition - Serie: III
1. Shoping Area
2. Villa Housine Area
3. New Housing Area
4. Industrial Area
Total Average
on Serie II
%
10
34
27
29
100
Moist.
3.18
13.86
9.07
11.40
37.51
Comb.
4.06
11.63
12.60
9.40
37.69
Ash
2.77
8.51
5.33
8.19
24.80
Date
Volatiles
3.47
10.37
10.94
8.15
32.93
: Jam
Fixed
C
0.58
1.26
1.66
1.26
4.76
ary 11 - 14, 1965
Hi
kcal/kg
166.90
453.56
511.38
338.14
1,469.98
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23
Solid Waste Transfer
The northern city of Hillerod has a transfer station as pictured
in Figure 15-6 and located in the previous map, Figure 15-3. The one-way
distance is 40 km (25 miles).
Recycling
The following Figure 15-7 shows a source separation truck dis-
charging sorted items into several of the recycling bins placed near, but
before the scale house. Thus, homeowners and businessmen who appreciate
the need for recycling, and drive their own vehicles to Copenhagen: West,
can also place their separated items into any of these several containers .
Solid Waste Disposal
Including demolition debris and household refuse, about half is
incinerated and half is landfilled northwest of Copenhagen and near Uggelose.
Negligible amounts of refuse are recycled.
Since the Number 4 Unit began operation in 1977, the landfill
has adopted the policy of charging more money for combustible loads than
non- combustible loads. Of the ash produced by West, 90% is recycled.
The remaining 10% or 10,000 tonnes (11,000 tons) is landfilled at Uggelose
12 km (7."i TMies) away.
The greater Copenhagen metropolitan area is now served by eight
(8) refuse fired energy plants: some are shown in the previous map, Figure
15-3. All of the following are within a 32 km (20 miles) semi-circle radius
of Copenhagen:
Vest (West) Roskilde
Amager Albertslund
Brondby Horsholm
Taastrup Helsinor
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24
FIGURE 15-6 . UPPER PORTION OF TRANSFER STATION AT HILLER0D
FIGURE 15-7 .
SOURCE SEPARATION TRUCK DISCHARGING SEPARATED
ITEMS INTO RECYCLING BINS BEFORE SCALES AND
TIPPING FLOOR AT COPENHAGEN: WEST
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25
DEVELOPMENT OF THE SYSTEM
History
Waste-to-energy began In Copenhagen in the early 1930's with
the 1932 commissioning of Gentofte two 144-tonne (158 ton) per day Volund
grate/rotary kiln furnaces, each with a three drum boiler as shown in
Figure 15-8. The steam was used to make electricity as specified by the
City's Electrical Board. This construction was followed by two similar
Volund units at Frederiksberg in 1934.
These two plants, see Figure 15-3 for location, served Copenhagen
well for forty years. During that time these plants had reached their
capacity and excess refuse had to be landfilled both inland and on the
sea coast. Referring back to the map, Figure 15 - 3, notice the large
undeveloped area in the western part of Amager Island. This was basically
low swamp land that has been filled in with both demolition debris and
household refuse.
During the 1960's, when knowledge of landfill leachate damages
became better known, and when neighbors became upset over blowing trash,
etc., local citizens groups on Amager Island were effective in getting
the attention of elected officials. Details are explained in Trip Report
14 that discusses Copenhagen: Amager. One reason for mentioning it in
this report is that the excitement about Amager encouraged the residents
west of Copenhagen to develop a similar system.
Excerpts from a locally provided summary comments about the
motivation for development.
"The need for a permanent solution to the refuse problems of
these municipalities made the foundation of the West Incinerator.
The possibility of dumping refuse in the open was not any more
feasible in the densly populated area.
These municipalities, therefore, had a common need in spite of
different structures in both population, trade and politics. This need
the municipalities sought to meet by mutual cooperation.
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26
FIGURE 15-8. FIRST VOLUND SYSTEM BUILT AT GENTOFTE IN 1932 AND
DECOMISSIGNED AO YEARS LATER IN 1972
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27
The transport of the refuse continued to be the job of the
municipalities on the principle that this problem very well could be
solved locally and that the small truck firms had a better contact with
both the local political councils and the community to be served.
Hereafter the cooperation was concentrated on this (i.e.the
agreed objective was twofold): To reduce the volume of refuse as much
as possible, due to the demands to dumping, and at the same time the
municipalities wanted to exploit any heat energy in the refuse.
Then the decision to build an incinerator plant was made,
situated so that it was placed centrally in relation to all the partnership
municipalities, with attention to driving distances.
The regulation therefore stipulates a condition, that the
municipalities shall establish an arrangement for payment of transport
so that municipalities with the shortest driving distance contribute
an amount to the municipalities with longer driving distance, in order
to obtain equal economy in transport.
The following types of refuse are treated:
Domestic Refuse
Garden Waste
Large-size Waste, such as Furniture
Industrial Refuse
Sludge from Treatment Plants
The joint community will further seek to assist other municipalities
with other types of refuse so far as it is possible within the environmental
laws.
The weighed-in amounts of refuse correspond to between 280 and
350 kgs per inhabitant per year. However, not actually giving the exact
amount per inhabitant in this area.
Since delivery of solid refuse is not compulsory the total amounts
cannot be made up, because still a good deal of refuse is taken to dumping
places.
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28
It is forseen that the joint community will seek to establish a
place for discarded items within the area, to be arranged according to the
enviromental laws.
This discarding area is to supplement the incinerator plant in total refuse
treatment for the 12 municipalities".
The other reason for mentioning Amager in the West (Vest) trip
report is that Volund's competitive approach was to provide both organizations
with a quantity discount if both purchased similar units.
The competitors at West were:
Heenan-Froud
Martin
VKW
Volund
Von Roll
Officials remember that VKW, Volund, and Von Roll had the lowest
single unit prices (i.e. non quantity discount). Other excellent Volund plants
in Denmark, the long history of successful operations at Gentofte and Frederiksberg,
the low (maybe not the lowest) single plant price, the quantity discount, and the
Volund headquarters being nearby all contributed to the decision favoring Volund.
Copenhagen: West is-owned by the twelve communities, it serves, as are
listed in the Organization Section at the end of this trip report. West started
operations in November 1970 with three 12 tonne (13.2 ton) per hour furnaces
assuming 2.500 Kcal/kg. Later in 1977, a fourth furnace rated at 14 tonne
(15.4 ton) per hour, assuming 2,500 kcal/kg, was installed.
Comment:
Many of the more precise interviewees refer to "xx
tonnes per hour assuming y.yyy kcal/kg." After all,
the limiting factor is not how much refuse can mechanically
be pushed through the unit. Rather, the limiting factor
is the heat release rate that will not unduly affect system
reliability.
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29
Future Planning of Refuse to Energy Capacity
A study, see Table 15-3 and Figure 15-9 , of refuse quantities in the
future was made in order to ascertain when more furnaces would be required, with
this knowledge, a financial plan (including surcharge) was implemented to allow
for accumulation of funds thus avoiding large loans at high interest rates.
The development was not quite according to the plan which called for
Unit #4 to be added in 1972. Population expansion has not been as rapid as
anticipated. (See Table 15-3). West purchased a furnace unit in 1976 and is
now considering a scheme with RDF. The surplus of paper, plastic and wood
contained in the refuse at the collecting source in the summer time will be
pelletized to fire in specially designed boilers in the winter time, when there
is more need for the heat in the district heating system.
Joint Cooperation of the Municipalities on Research
and Future Forms of Refuse Treatment
Clinkers (Ash)
The incinerator plant produces approximately 50,000 to 60,000 tons of
clinkers per year and this amount is landfilled according to environmental re-
quirements in cooperation with the State Forestry Department.
Other Methods of Refuse Treatment
The joint community of West Incinerator examines on behalf of all
partnership municipalities whether other methods of refuse treatment ahve been
developed, which in cooperation with the incinerator plant can provide the
municipalities with better environment and better method for the society. Figure
15-10 is an example of this total resources management philosphy.
The Future of Refuse Treatment
The joint community of West Incinerator is in charge, on behalf of the
municipalities, of continual examinations of the future refuse treatment and the
demands by the society to the muncipalities.
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30
Table 15-3. INHABITANT AND QUANTITIES OF REFUSE FOR COMBUSTION
Inhabitants
(people)
Household refuse
(tonnes/year)
Industrial and
garden refuse
(tonnes/year)
Total quantities
of refuse for
combustion
(tonnes/year)
Copenhagen
Suburbs
Total excl. G+L-T
Gentofte and
Lyngby-Taarbaek
Total incl. G+L-T
Copenhagen
Suburbs
Total excl. G+L-T
Gentofte and
Lyngby-Taarbaek
Total incl. G+L-T
Copenhagen
Suburbs
Total excl. G+L-T
Gentofte and
Lyngby-Taarbaek
Total incl. G+L-T
Copenhagen
Suburbs
Total excl. G+L-T
Gentofte and
Lyngby-Taarbaek
Total incl. G+L-T
1975
250,000
340,000
590,000
155,000
745,000
92,000
78,000
170,000
55,000
225,000
23,000
22,000
45,000
25,000
70,000
115,000
100,000
215,000
80,000
295,000
1980
250,000
375,000
625,000
157,000
782,000
100,000
95,000
195,000
60,000
255,000
25,000
25,000
50,000
25,000
75,000
125,000
120,000
245,000
85,000
330,000
1985
250,000
390,000
640,000
150,000
800,000
108,000
117,000
215,000
65,000
280,000
27,000
28,000
55,000
25,000
80,000
' 135,000
135,000
270,000
90,000
360,000
Gentofte and Lyngby-Taarbaek are big enough cities, far enough removed to
not be considered suburbs in this tabulation.
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31
7o
60
3o
lo
One furnace free for inspection in the summer.
Includes Copenhagen, suburbs; Gentofte, Lynby
and Taarbaek.
tonnes per hour
Refuse per hour
by continuously
burning
115% Winter
100% Average
95% June, July,
August.
1960 1965 197o 1975
1985 199o
0 Plant expansion for fourth furnace in 1972.
0 Plant expansion for fifth furnace in 1985.
FIGURE 15-9. LONG-RANGE PLANNING OF FURNACE ADDITIONS
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33
Philosophy of Cooperation
It would not be possible for each muncipality to carry out such
examinations and, furthermore, it would not be possible economically for each
municipality to meet with the future environmental demands made to the refuse
treatment in Denmark.
VOLUND'S RELATION TO THE NORTH AMERICAN MARKET
Volund A/G initiated activity in North America, January 9, 1948
with the F. L. Smidth & Co. Smidth had the "sole and exclusive rights to
make, sell and/or use the VOLUND INCINERATOR SYSTEM ... in the United States
... Canada and Mexico".
Also in 1948, Smidth and the Hardaway Construction Company of
Columbus, Georgia formed a joint venture company called Internationa] Incinerators
Incorporated (III) with offices in Atlanta, Georgia. Ill was to "devote its
best efforts to an aggresive attempt to obtain orders from purchasers...
(in North America) ... for the sale or installation of apparatus and
equipment made in accordance with the VOLUND INCINERATOR SYSTEM".
With this charter, III sold 13 municipal waste incinerators, 2 of
which had energy recovery. They also sold 3 industrial waste incinerators.
During this time of cooperation, III utilized many of the Volund A/G patents
and site-specific drawings. In addition, III developed many of their own
techniques and filed patents. Eventually many of the early Volund A/G
patents expired. Yet Volund A/G continued to file patents in America.
With the Congress passing the Clean Air Act of 1970 and the ensuing
regulations on incinerators, many units closed. Few new orders (regardless of
manufacturer) were placed after 1970. In fact III had some of the very last
orders. Nevertheless the future looked bleak.Ill survived on their replacement
parts business.
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34
Eventually the license agreement between F. L. Smith (the 50 percent
owner of III) ceased effective December 31, 1975. Smidth then sold its shares
to the other original joint partner, The Hardaway Construction Company.
Subsequently, Volund A/G and III (now 100 percent owned by Hardaway)
were not able to come to agreement on a new license.
Volund A/G initiated efforts to find a new licensee. Finally a joint
venture corporation was founded and is known a Volund USA.
An abreviated name used orally is VUSA. It is owned jointly by
the following parties:
Volund A/G (Glostrup, Denmark) 30 percent
Waste Management, Inc. (Oak Brook, Illinois) 30 percent
Jack Lyon & Assoc. (Washington, D.C.) 30 percent
Others 10 percent
We have been informed that VUSA would like potential purchases
Of VOLUND INCINERATOR SYSTEMS to contact:
Sales, Construction, Operations
Mr. Ronald Heveran
Director of Marketing
Advanced Systems Group
Waste Management, Inc.
900 Jorie Boulevard
Oak Brook, Illinois 60521
Engineering. Design, Purchasing|and Start-Up
Mr. Gvnnar Kjaer
President
Volund USA
900 Jorie Boulevard
Oak Brook, Illinois 60521
Frankly, both Volund A/G and III lay claim and probably desire
recognition for these American plants. All 13 municipal refuse plants
are shown in the current inventory published separately by both Volund A/G
and III.
Effectively, this means that a community desiring "something
that looks like a Volund grate followed by a rotary kiln" has two poten-
tial vendors. Some would speculate that this is an unnatural situation
that still has not settled.
VOLUND'S PREFERRED PROCEDURE FOR SYSTEM STARTUP
Volund has prepared a block flow diagram showing how they view
the developmental process for these systems (see Figure 15-11).
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35
1
1
1
| Waste Problem
W.nie Amount Preliminary W»ste TVD«
waste Amount Investigation waste types
_ U ,u J
1
Study —I Environment
Building Preliminnrv Proicct Mechanical
and Plant Techniques Preliminary Project Engineering
2
Fconomv — Approval Environment
fcconomy of Amhorities tnvironment
Offer
Planl TWhnmn* — — n»t?iil»rt Prniprf Mechanical
Plant lechmque Detailed Project Engineering
_-.._.- - . ~ . , ~
El-erection
3 4
Erection
Test Running
1 1 [ Preliminary Investigation • 3 • Turnkey Job
1 2 I Preliminary Project H^ 4 1 Machinery Delivery
I
FIGURE 15-11. VOLUND'S PROCEDURE FOR SYSTEM DEVELOPMENT
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36
PLANT ARCHITECTURE AND AESTHETIC ACCEPTABILITY
In most of the Scandanavian refuse fired energy plants that
were visited, the level of architecture has been excellent. Perhaps this
is because most of the systems produce hot water for residential district
heating. As such, they are located often in residential neighborhoods
that will accept only attractive refuse plants.
Plant architecture at Copenhagen: West is outstanding and will
be referred to often in this trip report.
It is interesting to compare design philosophies at Copenhagen
(West) with those at Zurich Hagenholz #3 unit. The philosophies are
opposite—and for apparent good reason. In Zurich, the current design
philosophy was to "put any extra money into the furnace/boiler and to
'get by' on architecture features and frills". This is consistent with
the recent history in Zurich of technical problems (in units prior to
the Unit #3 at Hagenholz) that are a real potential with many high
temperature steam systems.
Generally speaking, the Scandanavian refractory wall systems
produce hot water and thus do not expose themselves to high temperature
corrosion. Thus, the emotional fear of corrosion is not present and
excessive monies are not poured into the boiler.
Figure 15-12 shows a beautiful white swan enjoying the res-
ervoir at the West plant—a plant so aesthetically designed as to be
acceptable in almost any neighborhood. The following Figure 15-13 shows
the landscaping plan t>o necessary due to the residential surroundings
and the high volume of traffic passing on the two main highways of the
area.
In addition, the existing land at the time surrounding a
pond could not be used for any other practical purposes without the
involvement of filling with hard material which could give a proper
stable foundation for construction. Filling in would be quite expensive.
The city plan for road network included motor-ways and free-
ways. The site was chosen because of its easy access from two major high-
ways. Thus, ample space of about 25 acres was set aside.
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37
FIGURE 15-12. SWANS IN POND ON PROPERTY OF COPENHAGEN! WEST
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38
FIGURE 15-13. ARCHITECTS OVERHEAD PLAN FOR LANDSCAPING AT COPENHAGEN: WEST RFSG
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39
The aerial photo in Figure 15-14 shows the intensity of land use
ajoining the plant property. Finally, the exterior wall theme is portrayed
in the architect's rendering in Figure 15-15.
Another important comparison is the contracting agreement at
West versus the agreement at Amager. West was constructed under a "cost
plus percentage fee" contract. Amager, however, was constructed under a
"fixed price" contract. Despite the identical refuse input requirements
and similar processing equipment, there was more attention to aesthetics
at the West plant. As such, West was 25,000,000 DKr more expensive.
For buildings both plants were constructed on the same basis
while for machinery there was a price escalation.
The building height is 50 m (164 feet). The machinery hall
is 35 m (115 feet) high. However, the stack is very tall at 150 m (492 feet)
Unlike many plants, everything that could produce noise is
enclosed. Referring to Figure 15-16, notice that the tipping floor for
refuse collection trucks and for transfer trailers is fully enclosed.
The electrostatic precipitator, often on plant roofs is enclosed. Also,
all of the ash handling activities are located in the lower parts of the
plant.
Perhaps the only deviation from the "full enclosure—no noise"
philosophy is the ash reclamation activity. Ash reclamation, as explained
later, was only started in 1976-, long after the plant was otherwise
finished. The strong presence of the architect apparently disappeared.
While not enclosed, the processing is tastefully layed out.
The West administration building would be the envy of many
American corporations as a headquarters structure. The conference or
board room is so expansive that it is informally divided into three
sections (a) board room table, (b) small conference table and (c) lounge.
A part of the room is shown in Figure 15-17. Not many incinerator control
rooms have a plush lounge area like the one shown in Figure 15-18- Comments
were made several times during Battelle's visits in Scandanavia that
such pleasant surroundings are necessary to attract and keep the desired
kind of employees.
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I
FIGURE 1D-14. AERIAL PHOTOGRAPH OF COPENHAGEN: WEST AND ITS SURROUNDINGS
-------
FIGURE 15-15. EXTERIOR WALL ARCHITECTURE THEME AT COPENHAGEN: WEST
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45
TOTAL OPERATING SYSTEM
Battelle's host for the Volund visit was Gabriel S. Pinto. In
1976, he wrote an excellent article in an internal Volund publication*
that discusses basic design of the total operating system. The following
summarizes the article.
For purposes of the vendor's guarantee to the customer, there
must be a clear understanding of the relation between Maximum Rated
Capacity (MRC) and the Lower Heating Value (LHV). The numbers used in
the example figure are those associated with the Volund grate furnaces
followed by the rotary kiln furnaces.
For each furnace designed by Volund, a theoretical diagram,
similar to Figure 15-19, is developed. Its purpose is to show how the
MRC (tonnes/hr) is a function of net calorific value (kcal/kg).
As an example, assume that the LHV is 2,000 kcal/kg. Typically,
such MRC waste has the following composition:
Inerts 25%
Moisture 30%
Combustibles
r v 8.6%
Carbon
O / Q°/
Cellulose - 34.B/.
Plastics 1-6%
Total Combustibles 45%
100%
The refuse feeder is to be adjusted so that the refuse layer on
the grate is 1 m (3.3 ft). This type of refuse, at the named layer thick-
3 3
ness, has an average density of 200 kg/m (337 pounds/yd ).
More must be known about the specific system before the MRC
answer (in tonnes/hour) can be given. The effective grate area must be
known. The following formula relates key variables:
* Pinto, Gabriel S., "Maximum Rated Capacity (MRC) on Volund Rotary
Kiln Furnaces".
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46
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47
2
, tonnes, * Effective Grate Area (m ) ' Grate Load . kcal
~
Net Calorific Value kcal • 1000 kg
* kg ' ^tonne'
At this point, some rules of thumb need to be applied.
• For hotter refuse with LHV of 1800 to 2500 kcal/kg, the
grate load ranges from 600,000 to 650,000 kcal/m2 • hour
• For cooler refuse with LHV under 1800 kcal/kg, the grate
load ranges from 450,000 to 550,000 kcal/m2 • hour
Experience of Volund must be used to actually estimate the grate load.
But once estimated, the capacity can be determined. Mr. Pinto 's example
does not refer to any one system so we have arbitrarily added capacity
figures of 5.5 to 8.5 tonnes per hour.
An important design consideration can be seen from the capacity
versus LHV curve. It is uni-modal peaking at 1200 - 1400 kcal/kg. As
an example, it is assumed that the plant is nominally designed to burn
7.0 tonnes per hour of refuse assuming it to have a 2000 LHV.
Perhaps on a Spring day, rain is excessive. The moisture per-
cent rises from its normal 30% to 37%; the combustibles fall from 45% to
3 3
38%; the density increases from 200 kg/m to 300 kg/m and the inerts
remain constant. The air preheater remains unchanged and the use of any
other fuel remains unchanged.
With the conditions of the wet waste given, the operator may
increase the feed rate, raise the feed layer thickness to 120 cm (4 ft)
and thus increase the throughput from its nominal 7 tonnes per hour up to
8 tonnes per hour.
This of course has a logical limit. If the refuse becomes too
wet, full of inerts, and lacking in LHV, then less tonnes per hour can
be processed. The furnace could easily choke on even 5 tonnes per hour
of soggy rags and house furnace ashes if autothermic reactions are not
possible.
In the other direction, above a LHV of 2000, this particular
furnace should process slightly less refuse per hour.
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48
Mr. E. Blach, Volund's former chief engineer, wrote in 1969
an excellent paper outlining Volund's product offerings and its philoso-
phy. The following section presents some of the philosophy of how plants
should be operated. Several of his other sections appear later.
Forms of Operation
The best way of running an incinerator plant is running it 24
hours a day, i.e. continuous operation. The big variations of
temperature at start and shut-down cause more wear in a furnace
and the auxiliary machinery than a steady operation, and corro-
sion and cleaning problems, etc. in the boiler part also de-
crease by contiqual operation. With regard to possibilities of
maintenance and repair, continual operation is not possible for
a 1-furnace plant, and that is one of the reasons why an incin-
erator plant should usually consist of at least 2 furnace units.
Unfortunately, this is often not economically possible at the
small plants.
An ideal way of operation for plants with several furnaces is
obtained by always keeping a spare oven, while the other or the
others run continuously. Through a convenient rotatidn so that
the furnaces alternately are taken out of operation there is
plenty of time for inspection, maintenance and repair of each
furnace. Small damages can thus be found and repaired before
they spread and require big and expensive repairs. At one-furnace
plants, the possibilities of inspection are smaller and it can
be tempting to let a long time pass between maintenance and
repair stops so that the damages grow big and expensive to repair.
With non-continuous operation, which in practice is 1 or 2
shifts operation, the furnace is stopped, when the operation is
discontinued, e.g. the furnace is fed with suitable amount of
refuse proportionally to the stand-still period, after which the
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49
grate movement and combustion air as well as I.D. fan are stopped.
The natural draught will then keep a slow combustion, which de-
velop sufficient heat to keep the plant warm all through so that
it can quickly get up to full capacity, when it is started again.
After a couple of hours the temperature of the flue gases will
be so low, however, that there is the risk of condensation, and
thus corrosion in the convection part of the boiler, although
the boiler water still can be kept at full temperature, and the
boiler shunt can ensure min. 70° C return flow temperature.
Therefore, at stops of more than 6-8 hours there must be taken
special measures, such as by-pass with damper around the boiler
and its convection part. This is a rather difficult construction
to carry out in sufficiently strong and practical form because
of the high temperatures.
Furthermore, it results in the operational inconvenience that
changing over cannot take place till the flue gas temperature
is below 400° C, which normally means after 3-4 hours' stop.
During week-end stoppages the temperature of the boiler water
cannot be maintained, and it will in this case be necessary also
to keep the boiler warm by circulation of hot water.
Note: Three configurations of grate and kiln are possible. The rotary kiln
alone is used only on special industrial wastes and at low capacities.
For municipal waste, when the kiln is used it is always preceded by
the Volui.1. For smaller communities, a grate alone (with no rotary
kiln) is sufficient for municipal waste.
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50
REFUSE FIRED HOT WATER GENERATOR EQUIPMENT
Waste Input
The plant receives normal household, commercial, and light in-
dustrial refuse. Because of its two shredders it can also accept sub-
stantial quantities of bulky waste. Grass clippings and vegetation are
perhaps more prevalent than in many other systems in the Spring and Autumn.
There is talk now of accepting sewage sludge in the future.
Public and private organizations collect and deliver the waste
in normal garbage collection trucks. Transfer truck-trailers from Hillerod
bring waste from the northern communities. Special source separation
trucks bring refuse into the special bin area (Figure 15-20) at the elevated
entrance (Area 2) to the plant as shown in Figure 15-21. Private citizens
and businesses also use these bins.
Weighing Operation
Arriving trucks (some may visit the bins prior to weighing to
discharge source separated items) proceed to one of the two load cell,
50 tonne (55 ton) scales manufactured by Philips of Holland (see Figure
15-22). Drivers produce their universal plastic cards that ide'ntify the
vehicle owner, etc. This information, along with the gross weight, is
fed into the computer, where the tare weight, mailing address, etc. are
stored.
Relevant information is displayed (see Figure 15-23) in the
attractively styled scale control room on the cathode ray tube monitor.
Additional monitors inform the scale operator of traffic patterns within
the tipping door. The scale operation can also respond to requests com-
municated from the crane operator as to where waste should go to better
even the calorific content.
Occasionally the plastic cards jam, break, or become lost. In
this event, the driver would have to get out of the truck and spend several
minutes in the scale house filling out a form. The cards were replaced
on an as needed basis. They have changed the system so that every six
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51
Plastic Card Reader
Scale House
Recycling Mation /v
Paving Cinder Blocks Made From Recovered Ash
FIGURE 15-20. SOURCE SEPARATION RECYCLING STATION AT
COPENHAGEN: WEST
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52
1. Entrance
2. Recycling Bin Area and Scale
3. Enclosed Tipping Area
4. Refuse Pit
5. Furnace/Boiler/Pollution Control Room
6. Maintenance Area
7. Administration Building
8. Air Cooled Steam Condensers
9. Permanent Standby Boiler
FIGURE 15-21. MODULAR UNIT LAYOUT AT COPENHAGEN: WEST
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53
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55
months all of the plastic cards are changed at once.
At the time of the visit in October 1977, a particular card
would work at Amager, West, and the Hillerod transfer station. An iden-
tical Philips system was under consideration for the Roskilde Volund
plant as well. In theory the system could be used throughout Denmark to
the advantage of all.
Provisions to Handle Bulky Wastes
The scale operator directs drivers with bulky wastes to either
of the two Lindeman "Lomal 10" shears. The second shear was added in
1975. Now, about 40-50% of the refuse input is processed through the
shears. Previously, bicycles, tubs, furniture, etc. had been jamming in
the refuse hopper, chute, and ash discharge operations. The current rule
to drivers is that all garbage collection trucks and transfer truck-
trailers disgorge directly into the refuse pit. Equally as firm is the
rule that all other trucks (especially detachable container loads) must
discharge to the Lindeman shears.
3
The shears are adjacent to the pits. They are rated at 80 m /hr,
Operation is intermittent and only on the day shift when the operator is
present. The drive is hydraulic.
The maintenance record has been excellent. Blades are replaced
usually after one or two years. With the rule that all miscellaneous
truck loads must go to the shear, several problems have arisen.
The shear is sometimes difficult to operate when overloaded
with small-sized and wet refuse such as a truck load of grass clippings.
These shears cost 2.5 to 3.5 million DKr each.
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56
Waste Storage and Retrieval
West has a pit 56 m (184 feet) long, 17 m (56 feet) wide, and
13.5 m (44 feet) deep. The capacity to the tipping floor door level is
3 3
12,500 m (16,350 yd ). However, with refuse piled against several doors
and by piling refuse against the wall to the furnace,, the maximum capacity
3
3 3
can be doubled to 25,000 m (32,700 yd ). This converts to four days
maximum storage. The specific weight or density is 0.2 to 0.3 tonnes/m
(337 to 506 pounds/yd3).
The 12 refuse doors are described as double hinged flap doors
8.0 m (26.3 feet) high, 3.8 m (12.5 feet) wide, and 122 mm (5 inches) thick.
They are operated hydraulically. The tipping configuration was designed
carefully to allow for a door and also to permit full view of tipped
refuse by the crane operators.
Centered Crane
Control Room
The West pit is much deeper by comparison than Amager. The West
pit bottom is 4.0 m (13.2 feet) above sea level while Amager is 3.7 m
(12.2 feet) below sea level.
There are no fire hoses at West. The local fire department is used
for the pit fires.
The plant has two cranes (one active and one often in reserve), manu-
factured by Demag-Thomas Schmidt. Both crane operator chairs are located
in the crane control room above the discharge doors and centered above
doors 6 and 7, and at the hopper level. See Figure 15-24. Each crane is
rated at 10.5 tonnes (11.5 tons). Television cameras aimed at the hopper
assist the crane operator in setting the drop position over the hopper.
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57
FIGURE 15-24.
THE TWO CRANE OPERATORS IN THE
CRANE CONTROL ROOM AT COPENHAGEN: WEST
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58
Based on the many crane problems at Amager and the success in
curing them, West was more properly designed and has had fewer problems.
The polyp is controlled with a hydraulic motor located inside the bell
of the polyp top. There is a sensor so that when the polyp is more than
45° from its level position, it switches off and refuses to permit
further movement that might snag the cables. The polyp has additional
stability due to the four lifting strands as compared to two strands in
some less expensive systems as follows:
—open and close cable
hydraulic motor
L/l\ *l ,^
lifting cables
This cable and polyp system has worked exceptionally well and is considered
well worth the extra money.
Furnace Hoppers, Feeders. and Swivel Gate
The hopper dimensions at its top opening are 6.5 m (20.1 feet)
by 6.5 m (20.1 feet). Farther down, at its bottom, the dimensions are
2.3 m (7.6 feet) by 1.15 m (3.8 feet). Its height is 5.9 m (19.3 feet).
The walls are made from 8 mm (.3 inches) plain carbon steel.
The filling chute has a slightly larger width dimension than the
hopper: 2.35 m (7.7 feet) by 1.15 m (3.8 feet). It too is made of 8 mm
3 3
(.3 inch) steel. The chute volume is 19 m (671 ft ).
The swivel gate or damper is located in the chute. It is opened
when refuse falls on it and closed when no refuse is above it. Its function
is to prevent burnback.
The damper's dimensions are 2.3 m (7.6 feet) by 1.26 m (4.2 feet)
and is 10 mm (.4 inches) thick. The 2.3 m dimension gradually increases
to 2.7 m (8.9 feet) near the furnace entrance.
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59
Previously the damper (swivel gate) on Units 1, 2, and 3 was
located 2 m (6 feet) below the hopper/chute interface. Severe burnback
and metal warpage, as shown in Figure 15-25 was the result. The 12.7 mm (.5
inch) support iron plates warped in addition to the walls themselves. The
plant successfully reduced serious burnback by raising the damper level to
only .5 m (1.5 m) below the hopper/chute interface. West Units 1-3 are
equipped with special pneumatic air hammers that can be used to dislodge
jammed feed hoppers or chutes.
In planning Unit 4 (which began operation five years later),
the designers also specified that refractory brick should be extended
internally up to the hopper/chute interface. Even with this, there
has been some burnback.
Another cause of burnback in the early years was that the
crane operators would put too much refuse in. Except for flowing material,
the hopper should always be empty. There should be no refuse above this kind of
damper to interfere with its closing. Pursuasion and practice rectified
this problem. Unless radioactive monitoring is used, the crane operator
should view the hopper/chute interface if designed as West is designed.
Primary (Underfire) Air
The primary air intake is located on the hopper level as shown
in Figure 15-27. As such, the hopper floor is very dusty as is the in-
take mesh screen also. In future designs, Volund will likely raise the
mesh screen another 2 m (6 feet) above the hopper to reduce dust problems.
The air is pulled in and down by the Nordisk 1490 rpm, which can pull 45,000 Nm /
hour. The temperature is assumed to be 30° C (86 F) and the static pressure
is 230 mm water (2.25 k pascals) (9.06 inches water).
Primary air is delivered to both the grate furnace and the
rotary kiln, as described in greater detail in the Amager report.
Primary air is delivered to one of four hoppers under the grates:
Grate I (1 hopper), Grate II (1 hopper), and Grate III (2 hoppers).
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60
FIGURE 15-25. WARPED FEED CHUTE AT COPENHAGEN: WEST
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61
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62
FIGURE 15-27.
SLOPING AIR INTAKE FILTERS ABOVE
THE BUNKER AT COPENHAGEN: WEST
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63
The Unit #4 fan is 20% larger than the fans for Units 1-3.
Another West #4 difference is that primary air is delivered to a distribution
box around the seal ring. In Units 1-3, the air is delivered directly
to the seal ring.
Secondary (Overfire) Air - Boiler Room Cool Air
West Unit //4 is equipped with a normal fan which pulls 30 C
(86 F) cool air from the boiler room and supplies it to the furnace as
secondary overfire air. West also has hot flue gas recirculation fans as
described in the next section.
The Nordisk Ventilator forced-draft 150 Hp belt-driven fan,
T
running at 1,670 rpm, can pull 35,000 Nm /hour. The temperature is
assumed to be 30 C (86 F) and the static pressure is 460 mm water.
West Unit #4 normally uses the boiler room cool air. The air
is sent to two manifolds on each side of the furnace and above Grate III.
Each manifold has four nozzles as shown below:
o
o
o Secondary Air Nozzles
0 /
o /
0 . ^ Grate
o
Secondary (Overfire) Air - Flue Gas Recirculation Hot Air
Where it is assumed that the net calorific value of the refuse
may reach 2500 kcal/kg and over, the plants are installed with
recirculation of flue gas as this means of temperature control are more
efficient and cheaper. This is done to thermal shocks on refractory.
West Units #1-3, unlike Unit #4, use hot flue gas as secondary
air. The air is drawn from the flue gas leaving the hot electrostatic
precipitator. See Figure 15-28.
Another Nordisk Ventilator forced draft fan, this one at 150 Hp,
is belt driven at 1460 rpm. The fan is rated at 45,000 Nm /hour and de-
livers the 300 to 350 C (572 to 662 F) hot flue gas at 220 mm water
pressure (8.7 inches water).
-------
b4
FIGURE 15-28.
ROTARY KILN AND FLUE GAS RECIRCULATION
DUCT AT COPENHAGEN: WEST
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65
The use of ambient boiler room air at 30 C (86 F) or re-
circulated flue gas air, 536 to 662 C (280 to 350 F), is determined
by basic furnace design and the refuse lower heating value (LHV). Assume
that the furnace was nominally designed for refuse with a LHV of 2000
kcal/kg. If the LHV is well over 2000 kcal/kg, then cool ambient air,
rich in 0?, might shock the refractory and cause the Carborundum bricks
to grow and spall. Therefore, if the refuse is "hot", then warmer re-
circulated flue gas air, poorer in 0?, should be used. In contrast,
if the refuse is "cool" or wet, then ambient boiler room air, rich in
0_, should be used.
At Amager, where the refuse is cooler at 1800 kcal/kg (3240 Btu/
pound), they now use only ambient boiler room air. Refractory life has
improved.
For the reason mentioned above, the calorific value also being
lower than 2000 kcal/kg (3600 Btu/pound), the necessity of gas re-
circulation at West was not present and the ducts and fans for Units
1-3 were dismounted and stored.
Because of the low level of calorific value at the present,
the Unit 4 was designed for recirculated gas, but the necessary elements/
components were not purchased. This will be done only when the real
necessity is present.
Of the European vendors visited, Volund is the only manu-
facturer known to us to use recirculated flue gas.
Other common information is discussed in the Amager report and
will not be unnecessarily duplicated here.
The recirculation flue gas fan has a damper that is automatically
controlled. It sends a larger or smaller quantity of flue gas back to
the furnace depending on the furnace combustion temperature. The
dampers are adjusted so that the furnace temperature is always 900 to
1000 C (1652 to 1832 F).
Flue Gas Fan
An induced-draft Nordisk Ventilator flue-gas fan is located
between the electrostatic precipitator and the chimney. It is neces-
3
sarily the strongest fan and can pull 107,000 Nm /hour with its 220 Hp
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66
motor. It too is belt driven but at a lower speed of 1010 rpm. It
delivers the flue gas at 172 mm water pressure to the chimney. Flue gas
temperatures range from 300 to 350 C (572 to 662 F) . The fan has a
damper connected with a regulator which holds the vacuum in the furnace
constant at all times.
Fan Summary
Table 15-4 presents key design parameters for the four fans:
(1) F. D. primary air, (2) F. D. secondary air, (3) I. D. flue gas, and
(4) F. D. flue gas recirculation.
The plant people report that the four furnaces each with four
fans have experienced only minor maintenance.
Assuming the maximum refuse calorific value to be 2,500 kcal/kg
(4500 Btu/pound), the theoretical air is 3.01 Nm3/kg (48.3 ft3/pound) of
3 3
refuse. The actual air is 4.5 to 6 Nm /kg (72.2 to 96.3 ft /pound) .
3
After combustion, the theoretical combustion flue gas is 3.78 Nm /kg
(60.7 ft /pound) while the actual is 5.3 to 6.8 Nm3/kg (85.1 to 109.1
ft /pound).
The Nm should be defined at NTP (normal temperature _and
pressure) e.g., at 0°C and 760 mm Hg. To find the actual m at a
certain temperature the following formula is used:
3 273 + t M 3
m = - r — x Nm
where 273 is the absolute temperature, "t" the actual temperature in °C,
and Nm the m at NTP.
Furnace Combustion Chamber
The original Volund designers had two seemingly opposite design con-
siderations. First, the design should ensure proper drying-out of the
wet refuse. Therefore, there is a desire to use a gas counter-flow to
the waste flow as shown in Figure 15-29a.
On the other hand, there should be good burnout of putrescibles
and carbon. Therefore, the gas flow should parallel the waste flow as in
Figure !5-29b.
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67
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VWundM
FIGURE 15-29. GENERAL DESIGN CONFIGURATIONS FOR VOLUND FURNACES
-------
69
A compromise suggested by other vendors would be to simply com-
promise and have the flue gas exit centered over the grate as shown in
Figure 15-29c.
The Volund simplified answer is to put a wall above the grate
and to send some of the gases back toward the feed chute and the other
gases toward the ash chute as shown in Figure 15-29d.
The more elaborate answer from Volund is to attach a rotary
kiln at the end of the furnace grate as shown in Figure 15-29e. Here,
some hot gas returns back toward the feed chute to help dry the incoming
waste. Also, the other gases continue flowing with the waste out of the
grate area and into the rotary kiln. The heat supports further combustion
in the kiln to consume almost all of the putrescibles and unburnt carbon.
This configuration, known as the 2-way gas grate and rotary kiln
system, is the design at both Amager and West. The schematic for
Frederiksberg (1934) show the basic configurations. To restate, the
original two Volund plants (Gentofte and Frederiksberg) successfully
served Copenhagen for 40 years (Figure 15-30).
The volume of all space prior to the boiler is as follows:
Furnace Combustion Chamber """"" -
Rotary Kiln
Overhead By-Pass
Afterburning Chamber
Burning Grate (Forward Pushing Step Grate)
Information, for the record, regarding the Volund grate is dis-
tributed between the trip reports #14 and #15 (Amager and West) i.e. in-
formation is being purposely not duplicated. Part of this section is
taken directly from a technical paper written by Mr. E. Blach, former
Volund Chief Engineer, entitled "Plants for Incineration of Refuse" - 1969.
Figure 15- 31 shows the principle of a forward pushing step grate system
Volund. Volund grate bars on a table are shown in Figure 15-32.
This grate construction is built up of several grate sections,
each separated by a vertical grate transition bar. The ratio
of size between the individual grate sections and grate transi-
tions is determined by the composition of the refuse.
The individual grate section is built up of lengthwise-placed
sections of 180-300 mm wide laid up with an inclination of 18-
25°. Every other of these sections are fixed and every other
are moveable, and each section is built up of a through grate
bar, which is welded up, on which a number of grate blocks of
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70
FIGURE 15-30. FURNACE DESIGN (TWO-WAY GAS GRATE AND ROTARY
KILN) AT THE OLD (1934) FREDERIKSBERG PLANT,
NOW DISMANTLED
-------
71
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-------
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-------
73
specially alloyed cast iron are fitted, which are in turn
filled up with loose grate bars of cast iron.
The moveable sections are driven hydraulically by a transverse
driving shaft placed under the grate, which is connected to the
individual sections by pendulum driving bars. From a neutral
position the movement in forwards stroke is slowly raising, for-
ward going and then lowering and backwards going. In the back-
wards stroke the movement is slowly lowering and backwards going
and then raising and forwards going.
Along the side of grate sections, which are built into the wall
of the furnace there are a number of side sealing beams, which
through building in springs give the grate sections a transverse
flexible assembling.
The first grate section acts as a feeding and pre-drying grate
and apart from the last part of the transition bar it is covered
with grate plates. Ignition and the first part of the combustion
take place at the first transition and on the 2nd grate. The
final combustion and burnout takes place on the 3rd grate, and
calcining and cooling of the clinkers begin at the last part of
the 3rd grate and continue on the subsequent clinker chute.
The layer of refuse is 300-500 mm. The moveable grate sections
give a lifting, moving and turning movement in the lower half of
the layer so that the combustion air, which in a regulated way
is supplied from below, can get to all parts of the layer. At
the transition bars there is a supplementary turning, mixing and
air supply.
Volund supplies furnaces with either three or four separate grates,
Vest has three grates per furnace. There are r :;• *- important differences
between Units #1-3 as compared with the newer Unit //4. Units #1-3 have
long beams with pendulums and five (5) cylinders. Unit #4, however, has
shafts with two (2) cylinders.
Each of the Units #1-3 furnaces has two operating hydraulic pumps.
At some other installations, an additional hydraulic pump is used as a
standby. Each pump's capacity is 47 liters/minute (12.4 gallons/minute).
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74
2
Each pump has a 15 Hp motor. The resultant pressure is 75 kg/cm g
7
(1160 pounds/in ). The plant has one 600 liter (160 gallon) oil storage
tank.
Each of the first three grates have five hydraulic cylinders
with cylinder bases of 80 mm (3 inches) and strokes of 130 mm (5 inches).
The stroke frequency is 3 strokes per minute.
Having three grates means that there are two steps. The height
between Drying Grate I and Burning Grate II is 1 m (3 feet). Between Grate
IV and Final Grate III the height is 2 m (6 feet). Some Volund systems
(such as Roskilde, but not either West or Amager) have an afterburning Grate
III. The afterburning grate is used only on grate type furnaces without
rotary kiln and only when the waste to incinerate is of a difficult type
demanding 20 to 30 minutes extra retention time to complete burn out.
The final step, from the grate system to the rotary kiln, is
1 m (3 feet) high. The grate exit to the rotary kiln is shown in
Figure 15-33.
Plant officials estimate that the individual grate bars will
last about 20,000 hours. Stated in another manner, 100% of the bars are
replaced every 20,000 hours. Despite the Unit #4 being newer and simpler,
the average run between breakdowns is longer for Units //1-3.
Compared to Amager, the amount of small sized inert (ash) parti-
cles is less at West. Perhaps West's fewer inerts, less grass, and less
home furnace ash contribute to West's longer grate life.
Units #1-4 have the following configuration for the three grates
per furnace. All grate frames, bars , and grates are made from "Meechanite
HR.'1 The side seals are made from "Nicromax". Nicromax has a composition of
mainly 2/4 Cr/Ni based on 3.5 percent C, giving low tensile
strength, but high Brinnel hardness and resistance to heat.
All three grates have a 2.7 m (8.9 feet) width. The length and
area of the three grates are as follows:
Drying Grate 1 Burning Grate 2 Burning Grate 3
Grate Length (m) 2.5 2 5
Area (m2) 6.75 5.4 13.5
Furnace Refractory Wall
Volund furnace walls are refractory lined (and not lined with
water tube walls) inside a steel framework. See Trip Report 14 on Amager
for more design details.
-------
75
FIGURE 15-33. GRATE FURNACE EXIT INTO A ROTARY
KILN Al ONE OF VOLUND'S PLANTS
-------
76
The six furnaces for both Amager and West (three each) were
designed and built at about the same time. Because of their initial
problems, West Unit #4 was built differently and has performed better.
Volund originally chose Hoganus, a high-quality and expensive
refractory, for its lining. The bricks themselves were not a problem.
The difficulty, however, in Units #1-3 was that there were not enough
anchors between the iron structural framework and the bricks.
In addition, furnace/boiler room air, cool and 0_-rich,, was
often used. Under certain conditions this would cause the silicon carbide
refractory to grow and then spall 500 to 700 mm (1.5 to 2.3 feet) above
the grate. The SiC oxidizes to SiC>2 and C02«
The first three units had to eventually be completely redone.
More anchors were added. Secondly, the automatic furnace temperature sys-
tem was reset so that more of the secondary air comes from the 0,, poor and
warmer, 300 to 350 C, (572 to 662F) flue gas recirculation air. There was
thus less secondary air from the 02~rich and cooler 30 C (86 F) furnace/
boiler room.
Based on the Hoganus problems at Amager and West, another re-
fractory supplier, Junger and Grater, of West Germany was chosen.
They made sure that there were enough anchors. Unit //4 anchors are at a
density of 4 or 5 per m2.
When asked about Kunstler (Zurich, Switzerland) air blocks, Mr.
Jensleu mentioned that he did not know of them but he had heard many
favorable things about Dr. Stein of the Didier Company in W. Germany.
Kunstler uses perforated cast iron plates while Didier uses porous re-
fractory blocks. Both provide evenly-distributed side wall tertiary air to
prevent wall slagging close to the grates. Neither have been used at
Amager or West as of 1977.
Figure 15-34 shows the exposed refractory brick wall after a
section of slag has broken away.
Volund does not report the heat release area since the wall
enclosures are not designed for heat transfer as are the walls of a
water-tube wall furnace.
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77
FIGURE 15-34. BROKEN AWAY SECTION AND SLAG
ON WALLS AT COPENHAGEN: WEST
-------
78
Rotary Kiln
The rotary kiln is seen in its relationship to other key furnace
parts in a plant schematic of the now demolished Gentofte plant (see the
previous Figure 15-8) that served northern Copenhagen so well for 40 years.
The basic design (with the exception of major modifications to the boiler
and air pollution control equipment) remains the same today. To repeat,
again from Mr. E. Blach's paper:
Pre-drying, ignition, and the first part of the combustion takes
place on the grate system as described in the previous example,
but then the refuse slides into the rotary kiln, where the
final combustion and burning out takes place.
While in operation the rotary kiln turns slowly and thus creates
a perfect overturning of the burning refuse. The movement makes
the refuse travel a very long way and thereby stay for a long
time in the Viln. The system operates with the so-called divided
flue gas/combustion air circulation, e.g. the primary combustion
air is divided into two after having passed through the layer of
refuse on the grates,- one part passing through the rotary kiln
and one part passing over the layer of refuse on the grates up
to the top of the furnace, from where it is brought back to the
after burning chamber through the previously mentioned connecting
flue gas duct and here it is united and mixed with the gas coming
from the torary kiln.
Besides primary air secondary air is added over the grate
sections as well as the rotary kiln in order to ensure for
certain that the flue gases arc fully burned. By adding
a surplus of primary and/or secondary a:'r a cooling of the
combustion can be achieved. But this cooling function can be
achieved better and more effectively by using a flue gas
recirculation system, e.g., cooled flue gas is brought back
-------
79
to the combustion zone, over the grates, and at the rotary
kiln. While in operation, this cooling function is done
automatically so that the temperature is kept at 900°-1000° C.
The rotary kiln is built up of an outer heavy steel plate,
which lined with wear resistant fire-proof bricks on the in-
side laid up and built on an insulating layer direct up to the
steel plate. At the ends the kiln is furnished with special
sliding seals and transition sections and the whole construction
rests on two sets of running and guiding wheels, which at the
same time act as friction pinion, activated by hydraulic motors.
The speed of rotation can be regulated variably between 0 and
15 r.p.h.
The grate/rotary kiln design is used for capacities from 5 t/h
to about 20 t/h, but can be built also in larger plants.
The carbon steel shell (See Figure 15-35 ) has an inside diameter
of 4 m (13.2 feet). With the addition of refractory, the inside diameter
is reduced to 3.4 m (11.2 feet). Each kiln is 8 m (26.4 feet) long. Volund
will build kilns up to 10 m (33 feet). The volume is 73 m3 (2,578 ft-*).
The kiln is sloped downward at a 3 degree angle and revolves
upwards of 12 revolutions per hour (rph). It however, normally revolves
at 6 to 8 rph. If the furnace operator is told by the crane operator that
the refuse is wet or if he sees a disturbance in the kiln on the TV monitor,
he can easily lower the kiln speed (see Figure 15-36). The picture comes
from the water-cooled closed circuit RV camera, manufactured by Philips N.V.,
(See Figure 15-37) that is continuously pointed from the lower end of the
kiln. Figure 15-38 is a close-up of the West operating kiln looking toward the
grate/kiln rectangular interface.
The support rings (2), support rollers (2), thrust roller (1),
and the drive support rollers (2) are made from high tensile-strength
steel castings.
An excellent burn in the grate at Itabashi, Japan results in a smokeless
final burn in the rotary kiln as seen in Figure 15-39.
-------
80
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-------
82
FIGURE 15-37.
WATER-COOLED CLOSED CIRCUIT TELEVISION
CAMERA LOOKING AT THE ROTARY KILN FIRE
-------
83
W
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FIGURE 15-39. VIRTUALLY SMOKELESS BURN IN VOLUND ROTARY KILN
AT ITABASHI, JAPAN
-------
85
The two hydraulic motors per kiln are rated at 3 kg-m (7.26 foot-
pounds) and have a maximum speed of 76 revolutions per hour or 1.27 rpm.
The nominal reduction is 1:800.
The refractory bricks are anchored onto the steel shell. Moler
refractory is placed next to the steel shell. Then next to the Moler
refractory, Chimotte bricks of varying alumina and silica content (36 to 55
percent A1203) are used to line the inside of the kiln. The composition
is 85 percent SiC at the inlet.
To some extent, because of very high temperatures, the kiln is
self-cleaning. Slag does not normally accumulate on refractory walls.
However, at some other Volund plants having very hot conical kilns, slag
"rings" occasionally from within the kiln. Interestingly, this ring can
gradually move down the length of the kiln. It eventually disappears.
While not used at West, chemicals can be used to clean the kiln.
After Burning Chamber
Flue gas leaves both the grate section in an upward direction
while flue gas also leaves the kiln and rises. Occasionally (and during
the Battelle visit) slag will form on the 45° slanting lower surface in
the mixing chamber. Three men were observed for at least a day while
they removed slag. Apparently, a thermocouple had been installed in the
wrong place and therefore did not record the very high temperatures in
the chamber.
Boiler (General)
West and Amager have boilers completely separate and following
the combustion furnace. The units are refractory walled furnaces followed
by the boilers, i.e. Volund units are not "water wall incinerators/boilers".
The boilers at West and Amager are of Volund type, designed and constructed
by Volund. In time they found the Eckrohr type boiler suitable for incinerator
plants and these are an integral part of the new Volund plants like in Japan
and in the new Aalborg plant. The Eckrohr (translated "corner-tube") boilers
were built under a license from Professor Dr. Vorkauf of Berlin, W. Germany.
-------
86
When asked why the Eckrohr boiler is now used instead of the
formerly specified Volund boiler, the reply evoked the Eckrohr features -
features that seemed popular in several other places over Europe. (One
estimate suggests that 180 Eckrohr boilers follow furnaces of various
manufacturer's designs).
1. The four corner tubes are used not only to carry down-
stream water but are also the structural support foy the
whole boiler. This reduces construction costs.
2. The heat transfer rate is excellent.
3. The circulation pattern is good.
4. It has high efficiency.
5. It is a natural circulation boiler.
The market for energy demands slightly higher temperatures at
West than at Amager as follows:
West Amager
Energy form overheated water hot water
Water temperature leaving
plant 160 - 170 C 115 - 120 C
Water temperature return-
ing to plant 140 C 70 C
284 F 158 F
Heat output 21.5 gcal/hour 20 gcal/hour
Pressure (working) 16 kg/cm2 6 kg/cm2
225 psi 85 psi
The key reason for higher temperatures at West is that an early
customer was the Copenhagen County Hospital that needed hotter water for
sterilization and air conditioning.
The amount of combustion gas entering the boiler was provided
but as a function of refuse lower heating values.
Lower heating Value Amount of Gas
kcal/kg Nm-Vhour
Lowest 1000 33,000
Average 2000 77,000
Highest 2500 98,500
The combustion gas inlet temperature to the boiler is around
800 C ( 1472 F) . The outlet combustion gas temperatures range from 280 to
350 C ( 536 to 662 F).
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87
The boiler of Unit #4 has 54% more heating surface area than
O O f\
each of the Units #1-3: 1598 m (17,194 ft ) compared to 1,115 m (12,000 ft ).
Details as given are shown below with the codes also appearing in
Figure 15-40.
Units #1-3
First Pass Radiation Wall
Second Pass Radiation Wall
Third Pass Radiation Wall
Regular Radiation Walls
Scott Walls
Total Radiation Walls
Convection Section
Economizer Section
Total Heating Area
Figures given for Unit #4 are not as detailed:
Unit #4
Radiation Pass No. 1 121 m
Radiation Pass No. 2
Scott Walls
Turning Chamber
Convection Surface
Economizer .
1598
The "Scott Wall", not found in many boilers, is a wall of tubes
in the middle of a pass. Its purpose is to collect more heat, to help
reduce gas temperature, to increase residence time, and to redirect flue
gases to the hoppers so that more flyash falls out.
Plant officials have been happier with Volund's Unit #4. It
can process 14 tonnes (15 tons) per hour. The dust accumulation on the
tubes is lower and the boiler is easier to clean. The operational avail-
ability is better and there have been longer run times.
Volund officials pointed with pride to the lack of corrosion in
any of the four furnaces over the seven year period.
Units #1-3 Unit 4
Hours per year performance 6,500 6,500
Years of operation x.7 x2
45,500 13,000
Number of Furnaces x3 xl
Hours without corrosion 136,500 13,000
failure
-------
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-------
89
Mr. Pinto referred several times to their corporate position of
not participating in the municipal waste "direct firing: to very high
temperature steam" systems, i.e. above 350 C (662 F). They will not sell
anything that would likely have corrosive failures within a year or two. As
Mr. Pinto stated, "It's not fair (to the customer) to build a system that
might fail".
The highest temperature steam directly achieved (in 1979) from
Volund municipal refuse burning plants is 285 C (545 F) steam at the
Boras, Sweden plant. The highest temperature in any of the Volund plants is
490° C (914 F) at Ortvikens Papperbruk, Sundsvall, Sweden. The plant, which
is mainly for bark incineration, is equipped with an Eckrohr boiler producing
steam at 425 C (797 F). In a separate overheater the temperature is brought
up to 490° C (914 F) at 67 ato (985 psi).
Volund has six steam generating
Sundsvall, Sweden-steam: 28.5 t/h - 67 ato - 490
Volund has six steam generating plants as listed below:
o C
Itabashi, Japan - steam 28.9 t/h - 16 ato - 203.4° C
Nishinomiya, Japan - steam: 14.6 t/h - 18 ato - 208.8° C
Kawagushi, Japan - steam: 15.8 t/h - 16 ato - 203.4° C
Kohnan, Japan - steam: 35.9 t/h - 16 ato - 203.4° C
Boras, Sweden - steam: 16.5 t/h - 10 ato - 285Q C
If a customer wanted excellent burnout rates, wanted 500 C
(932 F) steam, and showed high interest in Volund; then Volund's licensee
would likely submit a bid. Volund might propose to raise the steam temperature
to 350° C (662 F) by burning refuse. The steam would then be input to a
topping off fossil fuel (likely oil) boiler to raise it to the 500 C (932 F)
level demanded.
Economizer
The economizer and its steel shot cleaning system (Figure 15-41
and 15-42) both were supplied by Eckstrom of Stockholm, Sweden. As at
Amager, the West exonomizers were fin tube with small spaces. The spaces
and corners became so clogged with flyash and steel shot, that they will
have to be replaced. Because of the clogging, the economizers at both
-------
90
FIGURE 15-41-
VIBRATING CONVEYOR FOR STEEL SHOT USED IN
BOILER CLEANING AT COPENHAGEN: WEST
-------
91
FIGURE 15-42. STEEL SHOT HOPPER ABOVE THE BOILER AT COPENHAGEN: WEST
-------
92
Amager and West have set the overhaul schedule for the whole plant. Until
the economizers are replaced, the unit will continue to shutdown every
1,500 to 2,200 hours. The manufacturer's original recommendation of
cleaning every 3,000 hours would have been mainly to restore efficiency.
The economizer is cleaned manually with brushes.
It is likely that the electrostatic precipitator corrosion
problems experienced were caused by the clogged economizer not doing its
job, i.e. lowering economizer flue gas exit temperature to below 300 C
(572 F).
Boiler Water Treatment
The plant deoxidizes boiler water with Hydrazine.
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93
ENERGY UTILIZATION EQUIPMENT
West produces superheated water at 160-170 C ( 320 to 338F') at
r\
16 kg/cm (228 psi). As stated before, this is at a higher quality than
the hot water at Amager because the key customer, the Copenhagen County
Hospital had already planned its utilities as follows:
• Hot water into radiators for space heating,
• Hot water into the heat transfer device to make steam for
use in the sterilization autoclave,
* Hut water into the absorption chiller to make cold water
for air conditioning in the summer.
As is true of most waste-to-energy developments, the large
charter energy user has n , influence over plant design. The hospital
location, along with the other current (1977) customers, is shown in
Figure-- i"~41
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94
'
&„ TJ^^0$£^f&?\-,
EXISTING DISTRICT HEATING NETWORK
1976/77
Lille Birkholm Heat Co. a.m.b.a.
about 2000 apartments, nursing homes,
a school, etc.
19 Gcal/hr
llegaard-Dyrholm' School
3 1,2 Gcal/hr
Copenhagen County Hospital
35 Gcal/h up to about 45 Gcal/hr in
1985. Summer heat consumption for
cooling
Herlev District Heat Co.
Shopping Center, City Hall, Library,
School, Apartments, etc.
6,5 Gcal/hr
Near the RR-station — RR Ground
Apartments
2,3 Gcal/hr
Connected in mid-77 1977)
Private Bank
0,24 Gcal/hr
Copenhagen County Pharmacy
at Herlev, under construction
6,5 Gcal/hr
^ The main pipe has a transport capacity
of 140 Gcal/h. (555 million Btu/hr)
At the moment, only 50% of this
f capacity is used.
FIGURE 15-43. MAP SHOWING DISTRICT HEATING
CUSTOMERS
V
-------
95
K0LLEGARD - DVRHOLM School
One of 25 Manhole Inspection and Repair District
Heating Stations
Oil-Fired District Heating Peaking Boiler
Adjoining Waste-to-Energy Plant
Lille Birkholm
Kollegird-
Dyrholm-
skolen
KAS
Herlev
Herlev
Bymidte
(a)
Herlev Hovedgade
Privatbanken I
KAS
Centralapotek
Ballerup Boulevard
FIGURE 15-44. DISTRICT HEATING SYSTEM AT COPENHAGEN:WEST
-------
96
With the original 3 furnaces, 73 percent of the heat produced is used.
(Figure 15-45). This is equivalent to 40,000 tonnes (44,000 tons) of oil per year.
They hope to more than double district heating demand by 1985 and thus 100 percent
of the main pipeline capacity will be utilized. If so, much of the increase will
have to come from oil-fired furnaces. One of the oil-fired boiler plants is shown
in Figure 15-44d. It is next to the chimney at the West refuse-burning plant. Under
the plan (where demand doubles), the refuse-derived energy utilization could rise to
85 percent—never really approaching close to 100 percent. (See Figure 15-46).
The superheated water at 160 to 170 C (320 to 338 F) is sent out in a main
concrete culvert as shown in Figure 15-47. The exit and return pipes are imbedded in
gravel. Each pipe is surrounded by 100 mm (4 inches) of mineral wool. The culvert is
then covered with a strong plastic lid. Varying configurations are used in the branches.
The used and cooler water 70 C (158 F) is returned in an ajoining pipe in the same
culvert.
The main pipe is constructed with occasional manholes (shown as Bl through
B25 in Figure 15-43) that permit inspectors to run cylinderical television cameras up
and down the water pipes to locate leaks (see the previous Figure 15-44c).
Once again, it is appropriate to repeat some of Mr. E. Blach's comments,
this time on heat exploitation:
Comments on Heat Exploitation
It will always be economically profitable to exploit the heat
from an incinerator plant, whenever possible.
The heat can be used for district heating, various industrial
purposes, drying and burning of sewer sludge or other sludge
products and for production of electricity.
-------
97
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-Plastic Cover
Carbon
Steel Pipe-
Gravel
-100 mm
Mineral Wool
^ —Concrete
FIGURE 15-47.
DISTRICT HEATING PIPE TUNNEL AT
COPENHAGEN: WEST
-------
100
If the heat cannot be exploited other arrangements must be made
to cool the 900-100°C, hot flue gas to below 350 C, before
it is led into the precipitator and the chimney.
Such a cooling of the flue gas can be done by adding air, water
spray, a combination of water spray and air and eventually by
letting the flue gas through a waste heat boiler and then cool
the water or steam.
Initial expenditures of plant as well as operational costs for
the cooling plant with air, water spray or a combination are
just as high as the costs of an actual plant for heat exploita-
tion with a possible supplementary air cooler. The sale of heat,
therefore, is an actual working income, which contributes essen-
tially to the operation of the plant, even with regard to the
extra costs for repair caused by wear and corrosion in the con-
vection part of the boiler part.
Least profitable is the production of electricity as the costs
of high pressure boilers and turbines are too high and the ef-
ficiency too low compared with the low price at which the big
power stations can produce the electricity. There is a great
need for drying and burning sludge and the use of waste heat
for the purpose can be expected to be common in the future. Sale
of heat for district heating or industrial purposes has, there-
fore, up to now been the solution which technically and economi-
cally has shown the best results.
-------
101
The monthly pattern, of energy demand and production is shown in
Figures 15-48 a and b; the difference being 3 furnaces versus 4 furnaces.
Figures 15-49 and 15-50 are maps showing the status-quo (1976-1977)
and the planned (1984-1985) energy distribution pattern.
The "light" areas are the connected customers of high temperature
o
water (160-170 C), while the "dark" areas are the secondary systems
o
using low temperature water through heat exchangers (90 C).
The square signature means peak load stations equipped with oil
fired boilers.
The round signature means heat exchanger stations.
The situation now and planned can be summarized as follows:
Incinerator furances/boilers (on line)
Incinerator furnace/boiler (in reserve)
Total Incinerator furnace/boilers
Oil Fired Boilers
Total Capacity
Yearly Consumption
1976/77
58-60 G cal/hour
210,000 G cal/hour
1984/85
3
1
4
2
4
1
5
4
90-110 G cal/hour
340,000 G cal/hour
-------
102
10.000 T
(a)
5,000 -
3 Furnaces
Heat from Oil Burner
at Herlev
Central Heating Station
Unused Heat from Refuse
Burning at West
Heat from Stand by
Oil Burner at West
Used Heat from Refuse
Burning at West
(240,000 tonnes/year
in 3 furnaces)
APR. MAJ JUNI JULI AUG SEPT OKI NOV DEC. JAN FEB. MAR
10.000
(b)
5.000.
4 Furnaces
Heat from Oil Burner
at Herlev
Central Heating Station
Unused Heat from Refuse
Burning at West
"••'•li*"-''- ' -f
^v. ".--%-
Heat from
Standby Oil
Burner at West
Used Heat from Refuse
Burning at West
(300,000 tonnes/year
in 4 furnaces)
APR MAJ JUNI JULI AUG SEPT. OKI. NOV. DEC JAN. FEB. MAR.
FIGURE 15-48. TONNES OF OIL PER MONTH OR EQUIVALENT ENERGY IN REFUSE
-------
39
m w~^±
- B V \ fab A "52^
FIGURE 15-50. DISTRICT HEATING PLAH
AS OF 1484/85
FOR COPEHACEN: WEST
nC.i: PBODUCTION
- Rafust Furnaces + 4 Oil Fired Boilers
rapacjtv 110 G cal/hour
HLAT DISTRIBUTION
Main Pipeline Capacity 1AO G cal/hour
Customer Connected Capacity 120 G cal/hour
Actual Maxloun Winter Usage 90 G cal/hour
Annual Delivery In 1976/77
Beating Season 340,000 G cal/year
[~~ | Connected Hot Water System
I ii^s| Connected Secondary System
B Peaking Oil Fired Plant
£ Heat Exchanger Plant
-------
39
FIGURE 15-49. DISTRICT HKATIHG PLAN
AS OF 1976/77
FOR COPENHAGEN: WEST
HEAT FRODPCTIOS
3 Refuse Furnaces + 1 oil Fired Boilers
Capclty 60 G c«l/hour
HEAT DISTRIBUTION
Main Pipeline Capacity 1-'*0 G cal/hour
Customer Connected Capacity 70 G cal/hour
Actual Naxlaum Winter Usage 58 G cal/hour
Annual Delivery In 1976/77
Heating Season 210,000 G cal/year
Connected Hot Water System
ls
-------
105
POLLUTION CONTROL EQUIPMENT
Both at Amager and West, Rothemeuhle two field electrostatic
precipitators (ESP) are the sole means of air pollution control now in
effect. Plant officials were hesitant about this and had thought of the
need to add a mechanical cyclone collector after the ESP. They wanted to
make sure that the larger paper particles would for certain be captured.
Therefore, they mandated that room should be available for adding the
cyclones later if necessary. The space is outlined with dash lines in
the previous Figure 15-2. As discussed later, there has been no need
to add any cyclones.
The ESP inlet gas flow is 107,000 Nm3/hour. The flue gas
temperature is designed to be around 350 C (662 F). Volund estimates the
maximum. Because of the clogging economizer section of the boiler, there
have been many excursions well above 35 °C (662 F). Volund estimates the
3
inlet loading to be 7.5 g/Nm .
Each of the two fields is a 8.5 m (28 feet) high and 7.0 m
(23 feet) deep. Flow-model studies were conducted. The average flow
velocity is 0.86 m/sec (2.8 feet/sec). The maximum is 1 m/sec(3.3
feet/sec). The flyash residence time in the ESP should be 1 to 2
seconds. The pressure drop through the ESP is 5 to 10 mm water (.2 to
.4 inches water). Each ESP field has two rectifiers. Volund would
permit a one-field ESP only on a small system where the regulations
are not as stringent.
Even though the ESP is housed inside the normally warm
furnace/boiler room, the ESP hoppers are equipped with electric heaters.
When the room temperature falls to 10 C (50 F), the heaters
prevent possible dew-point corrosion in the ESP.
Flyash is removed from the bottom of the EPS hoppers pneumatically
as seen in Figure 15-51. Again returning to Figure 15-2, the pneumatic tube
dumps onto a conveyor belt. The fly ash is transported to a steel silo
which has a continuous discharge into a humidifier. From the humidifier
the fly ash falls directly into the ash pit.
-------
106
FIGURE 15-51.
LOOKING OUT THE WINDOWS TAKEN FROM UNDER
THE ELECTROSTATIC PRECIPITATORS AT
COPENHAGEN: WEST
-------
107
Flyash is not to be mixed with bottom ash so that the bottom ash
can maintain its high pH and thus be recovered and used as "non-leaching"
and "non-cementing" gravel. The fly ash falls into a corner of the silo
and is not mixed with the clinkers.
3
The Danish regulation for particulates is 150 mg/Nm corrected
to 11 percent 0 and 7 percent CO (which are about the same). At West
3
the so corrected reading was well within limits at 90 mg/Nm . The Danish
Boiler Testing Company made the measurements. It was such an expected
low actual reading that caused Rothemeuhle not to put in the cyclone
collector. However, if the reading were higher, Rothemeuhle (at its
expense) would have had to install the cyclone.
Volund officials repeated a statement heard elsewhere in Europe
and America that, "for each one percent above 96% efficiency, the ESP
purchase price doubles". This of course is far from accurate. However,
it makes the clear point that going from clean air emissions to very clean
air emissions is very expensive.
they once tried to clean the ESP with water. Corrosion
developed. They now use the "dry method of compressed air.
-------
108
ENVIROMENTAL AND ENERGY CONSERVATION ASSESSMENT
Volund and West officials both referred to the air pollution and
energy conservation impact of the waste-to-energy system as compared with
the impact of burning the energy equivalent in tonnes of fuel oil in single
family homes. The contents of sulphur in the waste are lower than 0.5 percent
and emissions from the plant are under those found in a normal low percentage
sulphur oil fired plant. Ambient ground level tests carried out in Copenhagen
and surrounding areas did not show measurable traces of pollution from the
two large refuse plants: West and Amager.
The refuse fired energy plant at West emits as much acid formers
SO. and HC1, as do a combination of smaller furnaces burning fuel oil with
1 percent sulfur in the oil, i.e. 40,000 tonnes (44,000 tons) of oil. This
happens to also be West's energy equivalent in oil. Similarly, controlling
3
West's stack gas particulates to about 100 mg/Nm results in an equivalent
amount of emissions compared with burning 40,000 tonnes (44,000 tons) of
oil without any home air pollution control.
Atmospheric dispersion is also a point in favor of using a central
heating system instead of. individual home or apartment furnaces,, In Winter,
the area is subject to air inversions. Having thousands of small chimneys
3 to 10 m (10 to 33 feet) is much less desirable than having one large
150 m (495 feet) stack. At this height dispersion out of the country is
a substantial plus—for Denmark.
With respect to lead (Pb), West produces an amount equivalent
to 200 cars. But the refuse generation shed of the West plant has a
population of 650,000 people and about 300,000 cars. Thus the population's
automobiles produce 1,500 times as much lead than does the West plant.
Water pollution of landfill refuse leachate is also an environmental
issue. All other considerations set aside, if refuse is used for district
heating, then this raw refuse will not be landfilled. Refuse burning destroys
most harmful organics.
Figure 15-52 shows refuse Volume reduction as a function of various
solid waste treatment and disposal methods. It appears that the excellent
burnout rate in the Voland rotary kilm followed by thorough ash reclamation
result in volume and weight reductions of more than 95%. In 1975, West
consumed 255,000 tonnes of refuse, produced 60,000 tonnes of processed
ash for sale and landfilled 10,000 tonnes of unrecliamable material.
-------
109
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-------
110
Thus, only 4% by weight of the input refuse had to be landfilled. This
means that only 1 or 2% of the refuse by volume needs to be landfilled.
West's ash at a pH exceeding 9 is very basic and non-leachable when
concentrated. If this ash is recovered and recycled into roads, parking
lots, cinderblocks, patio bricks, etc., then landfill leachate is virtually
eliminated.
Energy conservation concerns are also important. By using
refuse as a fuel for the district heating system, 40,000 tonnes (44,000 tons)
per year of fuel oil are then available for other purposes.
Figure 15-53 has some efficiency numbers concluding that a district
heating system with multifamily apartment buildigns has a 70-85 percent
efficiency compared with indifidual single family homes having efficiencies of
50-60 percent. The losses shown are also caused by radiation losses due to
bad insulation etc. Today modern building laws demand higher insulation degree
with consequent higher efficiency in the use of heat.
Thus, on a total environmental and energy conservation balance sheet,
refuse as a fuel for district heating is much better than using fuel oil in
single family homes.
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112
ASH HANDLING AND PROCESSING
The subject of "ash" is discussed in two major sections of this
report. This section on Ash Handling and Processing discusses matters at
the West plant itself. The later section on Ash Recovery discusses physical
and chemical properties of processed ash as a usable gravel material. This
following section also discusses the encouraging environmental story of
ash percolate (leachate).
Returning to the subject of ash handling at the West plant,
mention should be made that West's experiences have been much better than
those of Amager - as fully discussed in Trip Report 14 - Amager. In
contrast to Amager's rubber belt conveyors, West uses a skip hoist as shown
in the dump position in Figure 15-54. The previous detailed cross sectional
view (see Figure 15-2) shows the position of the hoist rails.
Also to be noted are the two flapper doors (swivel gates) that
control in-plant ash atmospheres to minimize dust and noise. When the
hoist is traveling or dumping, the bottom door is closed while the top
door is open. Ash thus accumulates in the ash chute. When the hoist
returns and the chute has filled, the top door is closed and the bottom
door is opened to allow the ash to fall into the hoist bucket.
Another major difference is that Amager uses about 3 tonnes
of water per tonne of ash while West uses only 1 tonne of water per
tonne of ash.
Figure 15-55 is a diagram of the ash recovery plant. The ash
leaves the building and goes through a series of vibrators, sieves, magnets
and conveyors as shown in Figures 15-56 through 15-59. j^e ash less than
45 mm (1.8 inches) is stored on the ash mountain.
-------
113
FIGURE 15-34. SKIP HOIST DUMPING INCINERATOR ASH (SLAG) AT COPENHAGEN: WEST
-------
114
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made from
Reclaimed Ash
FIGURE 15-57. VIBRATING MACHINERY FOR ASH PROCESSING AT COPENHAGEN: WEST
-------
117
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118
ASH RECOVERY
Background
Ash recovery at Copenhagen: West is very advanced. It was the
subject of a 42 page report (English version available) co-authored by
the Danish Geotechnical Institute (DGI) and the Water Quality Institute (WQI)
entitled, "Cinders and Reuse." Sections of the report were written by
Mr. T. Balstrup (DGI) and by Mr. Sven Dige Pedersen (WQI). The report is
divided into two sections. The Geotechnical Qualities of Cinders and
Environmental Aspects Surrounding Combustion Cinders. Key paragraphs
have been repeated where it would benefit this trip report.
Back in the early 1970's, when Copenhagen: West was conceived,
the only clear alternative was to place cinders in a landfill with
plastic liners and a leachate collection system. Even by 1972 useable
research results were not available or known. In fact, in Denmark, re-
search had not even been started in this area.
Both institutions performed their work between 1972 and 1975.
While research was being conducted, the plant continued to place un-
processed ash in the Vestskoven landfill.
The research proved interesting and successful in the follow-
ing applications:
Application 1. Base and foundation for small and
lightly traveled local roads
Application 2. Bicycle paths
Application 3. Parking lots
Application 4. Below floor building construction
Application 5. Foundations carrying light loads
The following are numbers reflecting the normal annual operation:
Quantities
Tonnes
Quantity of waste combusted 240,000 to 300,000
Quantity of raw ash or crude cinders 50,000 to 75,000
-------
Quantity of usable gravel cinders 40,000 to 60,000
Quantity of reusable ferrous * 4,000 to 6 000
Ferrous Distribution
Caps and capsuls 20.8%
Identifiable tin cans 10.9%
Metal strips, spoons, and scissors 10.4%
Nails and screws 11.5%
Scrap metal - big pieces 17.7%
Scrap metal - small pieces 28.7%
Flyash
Flyash is excluded from the research because supposedly its
cement-like properties and low pH would interfere with the gravel-like applications.
Flyash at Copenhagen: West is separately collected in a corner of the clinker silo
and separately disposed.
Road Test Procedures
In order to establish a basis for initial evaluation and future
control, it was decided by DGI to employ the same test procedures for the
classification of the cinders as those used within road building for the
evaluation of sand and gravel materials. This was done with the full know-
ledge that they were dealing with a product of another grain structure,
and without systematical experiences from full-scale plants.
Laboratory tests included determination of grain density, ig-
nition loss, grain distribution analyses (Figure 15-60 ), density deter-
minations by dry embedment and by Proctor tests, CBR tests, permeability-
and capillary tests, and finally determination of strength and deformation
characteristics by triaxial compression- and consolidation tests. Technical
-------
120
Grain siz » d (mm)
0.06
Fine
1
Medium | Coarse
Sand-fraction
Fine
Coarse
Gravel- fraction
FIGURE 15-60. The variation interval for the 16 mm fraction of graded
cinders before (solid line) and after (dotted line)
compacting by field tests-
-------
121
results are presented in the report. Furthermore, examinations have been
made of crushing of grains of the cinders material by means of pounding
processes, and the deformation of the built-in cinders due to repeated
loads.
At the conclusion of the combustion process the cinders are
cooled down by watering. They subsequently have a moisture content near
20 percent which corresponds to the maximum quantity for building.
Tests were carried out in a very rainy and cold period which did not
change the moisture content of the cinders, as a satisfactory drainage
through the cinders to the surrounding area took place.
After sorting over a 4i> mm (,!.« inch; screen which mainly retains tin
and large pieces of iron, the cinders appear as a homogenous material.
It is so aesthetic that it does not resemble a waste product, and it can
be used in populated areas without problems. The sorted out large material
comprises only about 5 percent of the total cinders. In 1977, the process
had matured so that now 20 percent of the total cinders is removed for
ferrous recycling, reburning or direct landfilling. The cinders do not
cause any special dust- or smell nuisances.
The main results, from the test field show that for the graded
cinders a homogenous compacting is obtained which improves gradually
with the number of roller passages. On account of the good strength
quality of the cinders, the compacting depth is limited. However, there
is improvement when vibration equipment is used. By compacting to optimum
density, a crushing of the grains of the cinders occurs. The drained
layer of cinders will retain its optimum moisture content even during
periods with plentiful precipitation.
Laboratory tests furthermore demonstrate that a cementat:
occurs, which in the course of three to four weeks will increase th<
and deformation qualities of the cinders by primary loads by 50 to
-------
122
Parking Lot and Road Test Results
2 7
A 15,000 m (161,400 ft ) parking lot was covered with 60 x 60 x
8cm( 2x 2x .3 feet) concrete slabs. Underneath, at least:
40 cm ( 16 inches) graded cinders with a 5 cm ( 2 inches) screen of
gravel have been used. The cinders were laid out loosely in up to 40 cm
( 16 inches) thickness and compacted. After almost one year's use, only
significant settlings ( •* 1 cm) (less than 0.4 inch) have been registered.
For a temporary road approach system with relatively heavy
traffic in Herlev municipality, the graded cinders have partly been
used as foundation and base. The construction work shows that the
compacted cinders without asphalt surface could carry the traffic without
appreciable problems during the work period, even during a spell with
plentiful precipitation, and that the compacted cinders by the successive
replacement of the wet and mushy deposits could stand with an almost vertical
slope two to three meters tall. Settling and tracking tendencies will be
followed for the finished construction.
This road section of approximately 120 m (400 feet) is made
from 7 cm (2.8 inches) gravel "asphalt concrete, 13 cm (5.1 inches) stable
gravel and 28 to 38 cm ( 11 to 15 inches) graded cinders. After com-
pletion of the road construction height surveys at 16 points of the road
surface have been carried out in the period January 1976 to February 1977.
The measurements indicate settlings of 0 - 5 mm. While the main part
of the points with 28 to 38 mm indicate 5 - 10 mm frost heave in the
period February - March 1976, the point which had been replaced with
approximately 2 meters cinders the frost heave is<5 mm. The original soil
base consists of medium solid marine clay.
Finally, cinders have been used for foundations and base of
local roads and parking lots for a school in Ballerup. The foundation
and base of cinders was directly used as workroad during a period with
precipitation and changing thaw and frost. Apart from local softening
-------
123
of the uppermost centimeter of cinders, no significant impediments for
the work traffic were registered. The moisture content of the cinders
under the softened zone correspond to the optimum level. Observations
from these construction jobs so far seem to validate the use of cinders
for road construction purposes.
Environmental Tests - General
Since the autumn of 1971, the Water Quality Institute (WQI) have
carried out a series of tests for Copenhagen: West of the environmental
aspects by depositing and use of combustion cinders. The following tests
have been made:
- Accelerated washing out tests on laboratory scale.
- Tests of the washing out process form a non-covered cinders
depot.
- Tests for characterization of graded cinders.
- Tests of the washing out process from a parking lot, where
graded cinders are used as foundation material.
Environmental Test Results - General
A most interesting and positive test result is caused by the
pH of the cinders being around pH 9-11. The strong alkaline presence in
bottom ash is due to the high concentration of carbonate. The favorable
aspect is that in this pH range, most of the heavy metals are thermo-
dynamically stable. Thus fewer of the heavy metals will dissolve into
ground water solution for eventual entrance into the drinking water
systems. The next several paragraphs by Mr. Pedersen explain the en-
vironmental chemistry in greater detail.
-------
124
Liquid Percolate (leachate), j'resh Water, Sea Water, and Drinking Water
Tests and Results - Unprocessed Cinders
At Special Sanitary Landfill
The depositing of cinders was done in "depots", shaped like big
hollows with the under-side two to three meters below ground. The dug out
earth is put up like a circular wall, so that the hollows are four to five
meters deep. On the inside, the hollows are lined with a heavy, coherent
plastic diaphragm in order to prevent penetration of the percolate to the
groundwater. The percolate runs to a centrally located pump well, from
which it can be picked up and analysed.
The object was to shed a light on the washing out process from
an uncovered cinders depot, and to establish if there are traces of per-
colate in groundwater borings around the depositing site. Tests of
secondary groundwater and percolate of cinders from the locality in
Vestskoven where the cinders are deposited, were taken in the period from
June 1973 to October 1975.
No measurings or analyses of groundwater samples have evidenced
any adverse influence from the percolate of cinders in this period.
The concentration of macro ions (e.g. calcium, sodium, sulphate
and chloride) in the percolate is of the same size as the concentrations
in sea water.
Among the examined trace elements, hereunder also heavy metals,
only the concentrations of arsenic are bigger than the concentration in
the groundwater samples in the test period from June 1973 to March 1974.
However, it is substantially smaller than the drinking water criterion
for arsenic.
The concentration level for trace elements has not changed essen-
tially in the period 1974/75. In Table 15-5 analytical values of trace
elements in the percolate are compared with the values for river water,
sea water, as well as various drinking water criterions.
-------
125
TABLE 15-5. ANALYTICAL VALUES OF TRACE ELEMENTS IN THE PERCOLATE
Analysis
variable
Al
As
Pb
Cd
Cr(tot)
Fe
Cu
Hg <(
Mn
Zn
B
Percol
1973-74
min. max.
<1 1080
4.5 16.5
2 "10
e0.1 *20
10 «50
7 370
<1 80
)*05 0.29
29 300
10 150
ate
Fresh-
water
1974-75 medlan
min.
2,5
10.6
2
-------
126
The main cause of the low concentrations of trace elements in
the percolate is the high pH value ( •«• 10) of the cinders which gives the
percolate a pH value of approximately 9. At this pH level all examined
trace elements are thermo-dynamically stable in a solid form. The trace
elements are either immune (non-corrosive) or passive (coated with a dense
skin of the corrosive product which prevents further corrosion) to attacks of
water. The redox (reduction-oxidation) conditions in the depot (greatly
reducing with hydrogen sulphide development) increases this tendency
further, as possible dissolved trace elements from the top side of the
depot will be tied up as very sparingly soluble sulphide deeper down in
the depot. The presence of complexing ions (NH.+, Cl~, HCO~) will only
to a lesser extent be able to increase the solubility.
No higher solubility of trace elements than the one observed
up till now can be expected, as long as the present pH- and redox
conditions are maintained in the cinders. A noticeable change will first
occur if the pH value of the cinders falls to pH 7 or lower. Such a
change can only be caused by a neutralization of the alkaline parts of
the cinders with acidic precipitation. The following calculation shows
the length of time such a neutralization will require:
Alkalinity of the cinders: 0.975 equiv./kg
Acidity of rain water: 10~4 equiv./l (pH 4)
Quantity of cinders in depot 1: 15.600 tons
o
Quantity of percolate per year: 452 m
„„ . . . . „ 15,600 x 0.975 336,500 years
"Neutralization time": —452 x 1Q-*— years =
By the washing out from the depot some of the alkaline parts
of the cinders are removed. This means that a neutralization of depot 1
would last less than the period indicated, but still a very long time
(thousands of years).
-------
127
Solid Processed Cinder and
Soil Comparative Tests
By comparison with soil analyses, it can be seen (Table 15-6)
that the following elements in the cinders are present in a concentration
which is greater than the upper limit of the range of distribution for
concentrations in cultivated soil:
Cadmium
Chloride
Copper
Sodium
Lead
Sulphur (sulphate)
Zinc
Sodium and chloride mainly originate from wood and kitchen refuse (food
scraps) . A small part of the chloride may have been produced by the combustion
of PVC which is present in the garbage in minute quantities. Sulphate
is presumed to originate mainly from cardboard and paper waste. Zinc and
cadmium are present in the ratio 460:1 which means that the main part of
cadmium in the cinders has its origin as metal residues (pollution) in the
zinc (normal ratio 100:1 - 1000:1). The zinc is added from a great
number of sources. Copper presumably comes mainly from electrical wire,
and to a certain extent from copper-plated metal objects. Lead is pre-
sumed mainly to originate from food tins, paint, and painted articles
which are dyed with lead pigment, as well as lead batteries.
The high pH value of the cinders, pH = 10.1, fixes the trace
elements so that no significant quantities will be washed away from the
cinders materials. In slightly acid surroundings, which may be found if
cinders are spread and plowed down, the quantity of elements accessible
for assimilation in plants will increase as the pH is lowered.
Test on Parking Lot in Ballerup
In the autumn of 1974, I/S Vestforbranding received permission
to lay out a 40 cm deep layer of cinders as foundation of the parking area
near Ballerup's town hall.
-------
128
TABLE 15-6. ELEMENT COMPOSITION OF SOIL AND CINDERS
(ALL ANALYSES ARE MADE ON DRY MATERIAL)
Analysis
variable
Nitrogen
Phosphorus
Carbon
Chloride
Sulphate
Calcium
Sodium
Magnesium
Potassium
Aluminium
Arsenic
Lead
Boron
Cadmium
Chromium
Iron
Copper
Cobalt
Mercury
Manganese
Nickel
Silver
Zinc
Unit
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
g/kg
mg/kg
g/kg
mg/kg
mg/kg
mg/kg
g/kg
g/kg
mg/kg
mg/kg
g/kg
mg/kg
mg/kg
g/kg
Soil v
width
0.2
0.09
7
0.75
0.6
0.4
10
0.1
0..002
2
0.01
5
7
0.002
1
0,01
0.1
10
(0.01
0.01
ariation
1121
- 2.5
- 2,7*>
- 500
- 7.5
- 6
- 30
- 300 '
- 40
- 0.2
- 100
- 0, 7
- 3000
- 550
- 0. 1
- 40
- 0,3
- 4
- 1000
- 5)
- 0 .3
Soil average
/12/
1.0
0,65
20
o,*
2.1 + '
13.7
6,3
5
14
71
6
0.01
10
0,06
100
38
0.02,
8
0.03
0.85
40
(0.1)
0,05
Cinders average
0.66
2,71
12++)
81.5
10
32.2
7,6
2.6
3.2
21
8*8
1*56
•0.25
5.0
45
28
2;e
8.7
0.13
0,88
73
4.6
2,3
+) • Converted from sulphur.
++) : Converted from carbonate.
-------
129
The Danish Environmental Protection Agency and Copenhagen's water
supply plant wanted tests to be made of the drainage from the area. When
the parking lot was built, a diaphragm was put under part of the cinders
foundation, so that there was direct drainage from the lower side of the
cinders material to a collecting well. Furthermore, the whole area is
drained, so that it is possible to collect drain water which has passed
through the layer of gravel under the cinders.
Table 15-7 shows the results of tests of percolate, drain water,
and water running off the surface of the parking area. The percolate from
the cinders layer (sorted cinders) has the character of diluted percolate
from the depot in Vestskoven, as it has been diluted four to eight times.
The concentration of the trace elements lead, cadmium, copper, and zinc is
of the same magnitude as in the percolate from the Vestskoven depot, while
the concentration of chromium is smaller.
During the passage through approximately 1 m concrete, gravel
and the drain pipes, the percolate is oxidized, the ion strength is reduced,
and the main part of the nitrogen is absorbed by the gravel.
The concentration in the drain water of the trace elements lead,
cadmium, chromium, and coppe'r is less than or equal to that, in the percolate
before passage through the gravel layer, while the concentration of zinc is
somewhat greater.
Water running off the surface had a lower chloride content that
the drain water. The concentrations of trace elements in water running off
the surface is bigger for lead (8 to 16 times), copper (1.5 to 3 times),
and zinc (2 to 6 times), while it is of the same low size for cadmium and
chromium.
During a situation in September 1975 with 21 mm of precipitation,
the quantity of precipitation was removed from the area in the following
way:
Evaporation: 41%
Surface run-off: 36%
Drainage: 23%
It has been calculated that with the use of a drain water quantity
2
of 23 percent per year per m , a quantity of chloride is washed away from
-------
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131
the cinders which corresponds to the quantity of chloride which is added
2
per m roadway/parking lot when there are five to nine applications of
road salt during the winter season. The washed out quantity of chlor-
ide per year will decrease gradually as the present chloride in the cinders
is washed away. During the winter of 1973/74 there were 35 applications
in Copenhagen, and on some of these occasions, salt was distributed
twice, corresponding to about 50 applications.
Furthermore, similar calculations show that the yearly washed
out quantities of the trace elements lead, cadmium, chromium, copper, and
zinc with the drain water from the area is smaller than the quantities
which are added to the area yearly through precipitation from the atmos-
phere.
The calculations show that a very long period of time will
elapse (thousands of years) before the alkaline parts of the cinders have
been neutralized by acid precipitation.
The washed out quantities of substance with the drain water
from the newly built parking lot will expectedly decline gradually as
the area is consolidated and the joints between the flagstones become
compact, so that the part of the precipitation which runs off the surface
will constitute an increasing share, while the part of the precipitation
which is removed from the area through drainage will constitute a decreas-
ing share.
By using a dense surface dressing, such as asphalt and concrete,
the washed out quantities of substance from the cinders, other things
being equal, will be quite insignificant, as the quantity of drain water
which is a presupposition for a wash-out of the cinders will be extremely
modest.
Cinders as Excellent Landfill Cover Material
An alternative possible application for the cinders is the con-
centrated use of them to cover dumping grounds. Here the alkaline percolate
from the cinders will help to reduce acid conditions in part of the dumping
ground, so that the total washing out of trace elements from the dumping
-------
132
ground is reduced. However, the washing out of trace elements from the
cinders themselves will increase as the pH is reduced.
NOTE: To repeat, much of the above was borrowed from
this excellent report by Mssrs. Balstrup and
Pedersen.
[We request that Mr. Pinto obtain permission from these
two authors for us to repeat their materials. Perhaps
they could help us condense the material to 10 pages]
CHIMNEY
The chimney was constructed by a local contractor, Ramboll
Hannemann, using a Polish patented system for continuously pouring concrete.
The stack has a 2.8 m (9.2 ft) diameter. Most of the stack is lined with
280 mm thick plain carbon steel. The flue gas velocity is 27 m (89 ft) per
sec. At the top 10 m (33 ft), there is a corten steel core liner that is
used to prevent corrosion. It is an antiacid steel.
The stack height, is 150 m (495 ft). Volund had,recommended
only 100 m (330 ft). However, a local citizens group concerned about
wintertime air inversions prevailed at the 150 m height.
COMMENT: Interestingly, some citizen groups at other locations develop
equally strong favorable feelings about a short chimney that no
one can see.
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133
ORGANIZATION, PERSONNEL AND TRAINING
Organization
The West Incinerator partnership is made up of the following
municipalities:-
Refuse Tonnes
1972/73
Ballerup
Birker«5d
Farum
Gentofte
Gladsaxe
Glostrup
Herlev
Led^ j e-Sm^rum
Lyngby-Taarbaek
Vaerl^se
R«5dovre
Copenhagen
Subtotal
Hillerod (Transfer
Station)
Other Industry,
Institutions
13,900
5,900
3,000
24,900
28,900
8,400
6,400
1,000
17,700
4,300
11,000
52,600
178,000
6,600
33,800
Inhabitants
51,400
21,400
13,600
73,700
71,100
22,000
24,700
6,300
57,800
16,100
42,000
185,000
585,100
General Assembly
Council Members
6
3
2
6
6
3
3
2
6
3
5
7
35
Management
Members
1
1
1
1
1
1
1
1
1
1
1
1
12
Total 221,400
The partnership is a "joint municipal company which can be joined
by customers and other municipalities for a term of years.
The top authority of the company is the General Assembly (The
Council), to which the participating municipalities are entitled to elect
a number of members in accordance with the regulations and in relation to
the size of the municipalities. (See Figure 15-61).
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134
Members of West General Assembly and Board of Directors Chosen
for the Period of April 1, 1974 to March 31, 1978
BALLERUP KOMMUNE
Borgmester, cand. jur. Kaj H. Burchardt,
formand for bestyrelsen
Chauffor Hclge Hansen
Postvagtmester Skjold Jacobsen
TV-tekniker Arne Maischnack
Skatteradsformand Gudrun Petersen
Fabrikant Knud Pedersen
Typograf Knud 0. Rasmussen
BIRKER0D KOMMUNE
Trafikkontrollor Poul E. Frederiksen
Byradsmedlem Birthe Larsen
Major H. Sondergaard-Nielsen
Byradsmedlem Hans Rasmussen,
bestvrelsesmedlcm
FARUM KOMMUNE
Sognepra-st T. Gudmand-Hayer
Politiassistent Villy Hansen, best.medlem
Adjunkt Eva Moller
HERLEV KOMMUNE
Borgmester Ib Juul
Ingeni0r Erik Breith
Afdelingsgeolog Henning Kristiansen,
bestyrelsesmedlem
Kommunalbestyrelsesmedlem Hans Ohlsen
K0BENHAVNS KOMMUNE
Forretningsf0rer Andreas E. Hansen
Kontorchef H. Thustrup Hansen
Overlaerer Niels J0rgen Hougaard
Typograf Kurt Kristensen
Borgmester Lilly Helveg Petersen
Borgerrepraesentant Gunnar Ulbaek,
bestyrelsesmedlem
Overborgmester Egon Weidekamp
LED0JE-SM0RUM KOMMUNE
Borgmester Eigil Paulsen, best.medlem
Salgschef Ib Petersen
GENTOFTE KOMMUNE
Skoleinspcktor Erik Gruno
Viceskattedirektor Bent Kristensen
Fuldmaegtig. cand. jur. Birthe Philip
Kommunalbestyrelsesmedlem Inge Skafte
Husholdningskonsulent Ellis Tardini
Yicedirektor Steen Vedel, best.medlem
Adm. direktor Bjarne Lehmann Weng
GLADSAXE KOMMUNE
Postbud Kaj Bruhn Andersen
Redakter Ole Anderjen
Husholdningslaerer Kirsten Beck
Laerer Lauge Dalgard
Skolebetjent Tage Hansen. best.medlem
Fabrikant Otto Marcussen
L;rrer Lars Nielsen
GLOSTRUP KOMMUNE
Forretningsforer Beige Jansbol
Direktor Leo Lollike
Borgmester Martin Nielsen,
bestyrelsens naestformand
Ify gningssnedker Bent Wolff
LYNGBY-TAARB/EK KOMMUNE
Ekspeditionssekretaer Carlo Hansen
Borgmester Ole Harkjaer
Typograf Vivi Henriksen
Fagforeningsformand Birgil Cort Jensen
Civilingenior Palle Lovdal
Direktor Kaj Kramer Mikkelsen,
bestyrelsesmedlem
Cand. polit. Inge Schjodt
R0DOVRE KOMMUNE
Direktor Chr. Helmer Jorgensen
Typograf Ebbe Kristensen
Grosserer Tage Nielsen
Advokat Bent Osborg, best.medlem
Lagerarbejder Hans Rasmussen
V/ERL0SE KOMMUNE
Kommu nalbestyrelsesmedlem
Nette Holmboe Bang
Kommunalbestyrelsesmedlem
Elo Christensen
Borgmester E. Ellgaard, best.medlem
FIGURE 15-61. ANNUAL GENERAL MEETING PARTICIPANTS
-------
135
Each participating municipality choses one member to the mangement
irrespective of the size of the municipality.
The management consists of 12 members and the chairman and vice
chairman are chosen by the management. This method of election will ensure
full representation from the smaller municipalities.
The municipalities which have a contract with the Incinerator plant
of more than 10 years are admitted in the management as observers.
The management holds a meeting regularly on the 2nd Monday of each
month and the meetings are planned for a complete year at a time.
The permanent members of the management receive a minor fee, the
chairman and the vice chairman a somewhat larger fee. The fee is prepaid
each month.
Board of Directors
The daily leadership of the incinerator plant is handled by one
director who is assited by one operational manager (technical), one office
manager (administrative), as well as one technical adviser (research field).
Members of the Staff
In total is employed 61 staff members (1978) at the plant, in-
cluding above mentioned staff. The plant operates in three (3) shifts
during 24 hours and four (4) members are on each shift.
Technical Group
In order to coordinate the refuse treatment with the collection
sector there has been established a technical group made up of the engineers
of the participating municipalities as well as the management of West Incine-
rator.
Meetings are held every second month, whereby a considerable
contact between the environmental work in the municipalities and the West
Incinerator is maintained.
-------
136
Personnel
Details of the job title, shift, hours/day, days/week, and
duties are shown below:
• Administration - 1 shift = 8 hours/day, 5 days/week
- 1 managing director (part-time)
- 1 technical consultant
- 1 plant manager
• Bookkeeping - 1 shift = 8 hours/day
- 1 manager
- 1 bookkeeper/cashier
- 1 clerk (telephone attendant/typewriting)
- 1 clerk, (part-time) (typewriting)
- 1 office boy
• Cleaning - 1 shift - 8 hours/day, 7 days/week
- 2 women for cleaning offices and canteen. '
• Refuse cranes - 3 shifts » 24 hours/day, 7 days/week
- 3 crane operators
- 2 reserve operators for holidays, vacations, and sickness.
One of the operators will always be free as each operator
has 8 extra free hours (1 day) for each 40 hours work.
The other reserve operator works half a day with the
reserve crane cleaning the silo entrance ports and half
day for cleaning and removing the clinkers in the ash
silo.
- 1 reserve operator (day time) for lubricating and
cleaning. (This reserve will be in full work as soon
as more than two crane operators are free and on sick
leave).
-------
137
• Ash cranes - 1 shift = 8 hours/day, 5 days/week
(One reserve operator from the refuse crane.will help
-cleaning the silo in the afternoons.) The crane operator
is free on Saturdays and Sundays.
• Control Room, Furnaces, and Boilers - 3 shifts * 24 hours/day,
7 days/week
- 3 foremen. Their duties are to sample the water for the
boilers, start for testing the emergency generator, control
the water on the air conditioning system, control level of
hot water tank and changing (repair) of instruments.
- 3 boiler attendants. These attendants take care of the
boiler and help the foremen with their duties.
- 3 furnace attendants. These attendants watch the furnace
and equipment, clean the boilers and take care of general
cleaning in the plant.
- 3 reserve foremen
- 3 reserve boiler attendants
3 reserve furnace attendants. The reserve crew is used
for sick leave, vacation, and free days, and when not in
full use help the duty crew with their duties.
• Workshop - 1 shift = 8 hours/day, 5 days/week
1 foreman
2 electricians
6 artisans
• Cleaning - 1 shift = 8 hours/day, 5 days/week
- 3 unskilled workers. These workers help in the workshop
and the plant in general and take care of the general
cleaning
• Weighing Bridge - 2 shifts = 16 hours/day
- 3 attendants. The first attendant works from 6:00 a.m.
to 12:30 p.m. The second attendant works from 12:30 p.m.
to 9:00 p.m. The third attendant works from 8:00 a.m.
to 4:00 p.m. The third attendant will be on the first
-------
138
or the second shift in case of sick leave or vacations.
Every third week-end one of the attendants is on duty,
Saturdays from 6:00 a.m. to 3:00 p.m. and Sunday from
6:00 a.m. to 3:00 p.m.
• Refuse Reception Hall - 1 shift = 8 hours/day, 5 days/week
- 1 unskilled worker. Directs the traffic in the hall,
taking care that no large pieces of iron or similar are
discharged into the refuse silo.
• Refuse Crusher - 1 shift = 8 hours/day, 5 days/week
1 unskilled worker. Operates the crusher.
• Ash Disposal
- For this purpose, the plant contracts a lorry with driver
for transport of the ashes to a close-by disposal area.
Training (Education and Experience)
When staffing the plant, education and experiences are desired as
listed below:
• Managing Director
The title should explain the qualifications required to
manage the plant
- The managing director is only employed part-time as the
plant has a technical consultant who takes care of the
daily problems.
• Technical Consultant
- Mechanical Engineer degree of the equivalent
• Bookkeepers
- The personnel is defined by the degrees indicated and
positions held
• Crane Operators
- Artisan or unskilled worker trained at the plant
• Foreman
- Engineer (marit. ) with electrical installation.
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139
Boiler Attendant
- With official certificate as boiler attendant
Furnace Attendant
- Artisan or unskilled worker trained at the plant
Electrician
- Qualified as electrician
Weighing Bridge Attendant
Clerk training as the jobs require checking of accounts
and other administration work.
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140
ECONOMICS
The establishment of the incinerator plant was based on two main
economic principles:
1. There has been created capacity for each, partnership muni-
cipality on the prognosis of population development and a
capacity investment on this basis. (Initial Capital Invest-
ment)
2. Each partnership municipality contributes according to the
degree of utilization, i.e., payment by weight. (Annual Costs
of Operations, Maintenance and Amortization)
Capital Cost
The original three-furnace complete plant cost 140,580,222 Dkr
in 1969-1970. With the addition of the fourth unit in 1975-1976 and some
other items as outlined in Table 15-8, the grand total capital investment
cost is 204,972,634 Dkr. This table shows the capital investment cost
distributed both by assets and liabilites.
Annual Costs and Revenues
Table 15-9 is also a "balance of annual expenses and annual revenues".
By definition of "not-for-profit organization", the expenses must equal revenues.
In this case, they are equal to 41,908,696 Dkr. These revenues come from various
sources. The newer figures from the 1975/76 period are shown in Figure 15-9.
Citizens of Partnership Municipalities
Citizens pay in two ways: (1) per person and (2) per ton. In 1974/75
the results were"
A - Charge per person 30 D.kr. $5.07/person
(add to this)
B - Charge per tonne 35 D.kr. $5.92/ton
Hnece one might calculate for himself as follows:
-------
141
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Persond Charge = $5.07 + $5.92 315 ke
Person Year 1000 kg Person-Year
= $5.07 + $1.87
= $6.94 per person per year
This equals to about $20.03 revenue per ton from citizens. This figure might
also be defined as the net disposal fee for the household refuse portion of
the total waste stream.
Citizens of Non-Partnership Municipalities
Presently non-partnership municipalites pay 45 D.Kr. per tonne
($7.08 per ton), but no additional head tax. After five years, this can
be renegotiated. When refuse from nomal partners rises, the non-partners
will have to find other disposal means. The effect of the total effective
charge to non-partners being lower than for partners is to encourage more
waste in early years and thus more fixed expenses are covered.
Industries and Private Haulers
In a similar manner industries and private haulers are charged
only $45 D.Kr. per tonne ($7.08 per ton). This policy towards the industry
of the management of West Incinerator is an initiative to improve environ-
ment of the society, the industries hereby are motivated not to dump the
refuse in the open.
Citizens Bringing Refuse in Private Cars and Trailers
Any citizen driving his own vehicle can bring refuse to the refuse
treatment plant at no charge. He may offload his material and place it in
any of the segregated bins, i.e., ferrous in one bin, mixed color glass in
another bin, cardboard in yet another and finally mixed refuse to be burned in
another bin.
-------
144
Sale of Energy to the District Heating Network
During the 1974/75 heating season, hot water was sold for 32 D.Kr.
per tonne ($5.02 per ton). This figure has risen substantially since then.
Profitableness at Exploitation of Heat
For the final time, Mr. Blach's comments are entered into the
American record. This presents the economics of a 3 x 12 t/h plant versus
a 2 x 3 t/hr plant. The analysis uses three different Kcal/kg estimates
and two utilization rates.
"As mentioned before, the cost of the installation of a boiler
for the recovery of the waste heat can be expected to be of
the same magnitude as the cost of other forms of installation
for the cooling of the flue gas. In the same way, the operational
and maintenance costs can be calculated to be of the same magni-
tude provided the boiler construction is executed correctly
and appropriately, taking into considering the special corrosive,
wearing, and clogging properties of the flue gas.
As previously mentioned, the income from the waste heat sales
will be a real operational income which can cover a larger or
-------
145
smaller part of the operational costs, depending on how large
an amount of the produced heat can be sold and at which price.
The following enclosed two tables (Tables 15-10 and 15-11) show
examples of operational costs (exclusive of interest and
decpreciation) and incomes resulting from heat sales from a
large plant with three units of 12 t/h and a smaller plant with
three units of 3 t/h, calculated for net calorific values of
1,500, 2,000, and 25,000 Kcal/kg and with an effectivity of
burning capacity for the smaller plant for 50 percent and 75
percent, respectively, and for the larger plant 65 percent and
80 percent, respectively, of the nominal capacity. As a total
sale of the produced heat all the year round cannot normally
be expected, there has only be calculated the incomes deriving
from sales of 75 percent of the produced heat.
The obtainable selling price for the heat—here rated to Dan.kr.
20, -per million Kcal—will be determined by the fact that it
should be able to compete with the production price ,for a normal
oil-fired plant, i.e., among other things, it will be dependent
on the price of oil. When in competition with heat from power
stations, the selling price is lower (Dan.kr. 12,—15,—per
million Kcal).
As shown on the tables, the incineration capacity (line 1) and
operational costs (line 6) are equally rated for the different
calorific values. This, of course, is an approximation, but
nevertheless close to the real figures as far as the operational
costs are concerned, which will increase only little with the
increase of the calorific value, whereas the incineration
capacity may vary with the calorific value, depending on the
refuse composition, so that the capacity can normally be
expected to increase for lower calorific powers. This means that
the values for the operational costs per ton refuse incinerated
-------
146
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148
can be expected to be proportionately lower for the refuse with
the lower calorific value than for the refuse with the high
calorific value.
As regards the small plant, there has been calculated with two-
shift operation at 50 percent exploitation and three-shift
operation at 75 percent exploitation, and the plant closed on
Saturdays and Sundays. For the larger plant, calculations are
based on continuous operation all days of the year.
It can be seen that the operational costs per burnt ton of
refuse '(line 7) are much cheaper for the large plant than for
the smaller one. The operational costs for the small plant
executed as grate furnace and with mechanical gas cleaning,
and for the large plant executed as grate/rotary kiln furnace
with electrostatic precipitator, will be almost equal per ton
of plant capacity. With uniformly rated interest and deprec-
iation conditions, the large plant will consequently also have
the lower total operational costs per treated ton' of refuse.
Accordingly, with the large plant, a more effective and secure
refuse treatment, a better gas cleaning as well as a cheaper
treatment price are achieved."
FINANCE
The financial arrangements were straightforward. The 12 munici-
palities based on population put in 25,000,000 D.Kr.. The remaining 115,000,000
D.Kr. ($16,284,000) was borrowed at local banks. The payoff period is
variable as well as the interest rate that has averaged about 8 percent.
The investment contribution from the partnership municipalities is not
paid back and does not accummulate interest. However, the investment
can be increased or decreased by working profits or deficits.
-------
149
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152
TABLE 15-17. EXCHANGE SATCS FOR six EUROPEAN COUNTRIES,
(NATIONAL MONETARY UNIT PER U.S. DOLLAR)
1948 TO FEBRUARY, 1978(a)
1943
1949
1950
1951
1952
1953
1954
1955
19;6
1957
1953
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978 (Feb.)
Denmark
Kroner
(D.Kr.)
4.810
6.920
6.920
6.920
6.920
6.920
6.914
6.914
6.914
6.914
6.906
6.908
6.906
6.886
6.902
6.911
6.921
6.891
6.916
7.462
7.501
7.492
7.489
7.062
6.843
6.290
5.650
6.178
5.788
5.778
5.580
France
Francs
,(F.Fr.)
2.662
3.490
3.499
3.500
3.500
3.500
3.500
. 3.500
3.500
4.199
4.906
4.909
4.903
4.900
4.900
4.902
4.900
4.902
4.952
4.903
4.948
5.558
5.520
5.224
5.125
4.708
4.444
4.486
4.970
4.705
4.766
W. Cerraany
Deutsch Mark
(D. M.)
3.333
4.200
4.200
4.200
C.200
4.200
4.200
4.215
4.199
4.202
4.178
4.170
4.171
3.996
,3.998
3.975
3.977
4.006
3.97?
3.999
4.000
3.690
3.648
3.268
3.202
2.703
2.410
2.622
2.363
2.105
2.036
Netherlands
Guilders
------- |