VDI-RICHTLINIEN
May I960
VEREIN
DEUTSCHER
INGENIEURE
Gasauswurfbegrenzung
' Schwefelwasserstoff und andere
schwefelhaltige Verbindungen auBer
Schwefeidioxyd Kokereien und Gaswerke,
Kohlenwertstoffbetriebe
VDI2109
RESTRICTING EMISSION OF HYDROGEN SULPHIDE AND
OTHER SULPHUR-CONTAINING COMPOUNDS,
EXCEPT SULPHUR DIOXIDE, FROM GAS GENERATORS IN COKE
GAS, AND COAL-CONSTITUENT PROCESSING PLANTS
This publication, translated from the German, was prepared by
the Anthracite-Mining Association, Essen, All rights reserved.
Reproduced with permission by the
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Washington, D. C.
VDI-Kommission Reinhaltung der Luft
VDI-Handbuch Reinhaltung der Luft
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Foreword
This is one of several dozen VDI Clean Air Committee specifications
on air purification which the Division of Air Pollution of the U.S. Public
Health Service has obtained permission to translate, publish, and distri-
bute in limited quantity. A complete list of the VDI publications being
published by the Division of Air Pollution appears on the inside back
cover. Because the VDI Committee from time to time revises these
specifications, this and other publications in the series may be super-
seded by later publications.
The VDI Clean Air Committee specifications are compiled by trade
or professional associations and published by the Committee. The Com-
mittee has neither official status nor regulatory authority, although West
German governmental agencies participate in its activities. Air quality
specifications published by the Committee are therefore advisory, rather
than regulatory. They may however later be adopted by West German
governmental authorities.
The English translations were done by the Joint Publications Research
Service of the Office of Technical Services, U.S. Department of Commerce.
It should be borne in mind that various terms literally taken from the Ger-
man do not have the same connotation in English} for example, the word
"standard" frequently appears where the word "criteria" might better
reflect the comparable American meaning, since in this country "standard"
is generally meant to imply a legally enforceable value, while "criteria"
usually means a recommended value upon which standards may be based.
The publication and distribution of these translations by the Public
Health Service constitutes neither endorsement of the specifications nor
of the air quality or emission limitations recommended in them. We
believe that they contain much useful information that would otherwise
not be available to non-readers of German and for this reason have made
them available to workers in the air pollution field in the United States.
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RESTRICTING EMISSION OF HYDROGEN SULPHIDE AMD
OTHER SULPHUR-CONTAINING COMPOUNDS,
EXCEPT SULPHUR DIOXIDE, FROM GAS GENERATORS': IN COKE,
GAS, AND COAL-CONSTITUENT PROCESSING PLANTS
Prepared by:
The Anthracite-dining Association, Essen.
VDT. No. 2109, May I960
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TABLE OF CONTMTS
VDI Committee for Air Purification . . . i"v
Introduction ........*. ............ 1
1. Technology ........................ 2
1.1 Coal-Constituent Processing Plants ............. 2
1.2 Sulphur Content of Coking Products ........... 3
1.3 Coke-Oven Gas <>.<,.. ................... k
l.U Gases with High Sulphur Concentration ........... 6
l.ljl Condensation 6
I.lj2 Ammonia Scrubber . . . . . . „ , 6
1.1*3 Ammonium Sulphate Plant 7
l.Ui Benzol Scrubber and Benzol Plants ............ 7
1.U5 Desulphuration of Gas ...... 12
1.U51 Dry Refining Process .................. 12
1.1^2 Wet Refining Process 12
1.U6 Sulphur and Sulphuric-Acid Production
Installations r. . 12
2. Measures for Reduction of Emission. . . 13
2.1 General Measures . . . . 13
2.2 Special Measures 13
- ii -
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Table of Contents (continued) Page
3. Guidelines for the Restriction of Emission . 15
3.1 Restriction of Emission on the Basis of Immission . . . , 15
3.2 Reduction of Emission by Technical Measures . 15
iii -
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VDI COMMITTEE FOR AIR PURIFICATION
The VDI Committee for Air Purification is composed of experts in
all fields of importance for air purification. These experts col-
laborate with the Comittee on their own responsibility and without
compensation and are proposed for the Committee by the following
societies and institutions:
German Society for Hygiene and Microbiology
German Society for Oil and Coal Chemistry
German Society of Gas and Water Experts
German Meteorological Services
Society of German Chemists
Society of German Iron Mine and Steel Mill Experts
Association of Anthracite Mines
Technical Inspection Associations
Society of German Steel Mill Experts
Society of German Foundry Experts
VDI Trade Section on Dust Technology
Association of Steam Boiler Owners
Scientists from Universities and Institutes in Biology,
Chemistry, Toi'estl'j and Agriculture^ Hunan and
Veterinary Medicine, Metallurgy, Physics, and
Technology
Research Institute of the Cement Industry
Federation of German Industry (Chemical Industry, Oil
Industry, Automobile Industry, etc*)
German Federal Railroads
Federation of German Farmers
Federation of Community Associations
Settlement Federation of the Ruhr-Coal District
Competent Federal and State Ministries
Institute for Water, Soil, and Air Hygiene of the
. Federal Public Health Service
Public Inspection Services
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INTRODUCTION
The TOI Specifications on Air Piorifieation are divided into
the following groupss
10 Permissible Immission Concentration (PIC-values)
2. Calculation of the Distribution of Dust and Gas
3<> Restriction of the Emission of Dust and Gas
k<> Dust and Gas Measuring Techniques.
In the evaluation of problems of air pollution, the inner rela-
tion of these four groups of specifications most be considered.
The Committee for Chemoteehnieal Investigations on control of
quality and operation (Chemists Committee) in the Anthracite-Mining
Association has assumed the task, upoa instigation of the VDI Com-
adttee for Air Purification, to investigate the sir pollution caused
by coke and gas plants.
In coke and gas plants, dust, tar, mist and gas are emitted
during several production stages, . The present VDI Specifications
concern the ©mission ©f hydrogen sulphide and other sulphur con-
taining compounds not including sulphmr dioxide,, by coal-constituent
processing plants. The essential points treated herein are the
occurrence of hydrogen sulphide and other sulphur-containing compounds
not including sulphur dioxidej maastaraa for the reduction of emissions
and guide lines for the r©stei@ti©n of emission„
Special V31 Specifios&ioss are published on restricting the
emission of siilptaje dioxide by the mst© gases of' coke ovens and eoal-
eonstitueat processing plants„ .
- 1
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101 Coal-Constituent Processing Plants
Coal-constituent processing plants serve for treating the raw
gas obtained from the coking of coal and for the recovery of the eoal-
constituents contained in the gas.
The gases and vapors discharged from the coke oven are cooled
in the receivers of the coking battories and in the subsequent gas
preeoolerso Swing this, tar and condensate separate out during the
proeess (condensation).
Two processes ar© utilised for the subsequent production of
ammonia freas coke even gss» In the semi-direct process, the preeooled
gas is washed in saturators or in spray-scrubbers with diluted sulphuric
aeid which converts ammonia into asHraonium sulphate. The- ammonia sepap
rated out with the eandensat© in eooling the gas is distilled and
again added to the gas ahead ©f the saturators (ammonium-sulphate
In th© indireet-reeevery process, the gas is scrubbed with water,
and depending ©n tgrp© ©f construction and method of operation, a greater
or lesser part of hydrogen sulphide, carbon dioxide and other gaseous
eompomids is washed out (ammonia scrubber)0 The outflow from the
scrubbers and th© condensate are dCstilled together and the resulting
ammonia-sontainiBg vapors ar© passed through diluted sulphuric acid in
saturators0 Aasn©nium sulphate' iati precipitated in the saturators
(anmonium-sulphate plant). .The.vapors froa the saturators, free of
ammonia but containing hydrogen sulphide, are either returned into the
coke-oven gas ©r are proc@sseJL4n Slaus furnaces and/or in sulphuric-
acid plants which produce sulphur "or sulphuric acid from the hydrogen
sulphide contained in the waste vapors (sulphur and sulphuric-acid
.. F©r recovery of volatile hydrocarbons, the coke oven gas is
washed with washing oil in scrubbers„ The enriched washing oil is
redistilled which produces raw gasoline (benzol scrubber and benzol.,
plant). In seme eoking plants, th® volatile hydro-carbons are
recovered only by washing with washing oil or undercooling after con-
densing the gas.
. 2 -
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The separation of hydrogen sulphide from coke-oven gas is
carried out either by the dry or by the wet process (desulphuration
of gas).
1.2 Sulphur Content of Coking Products
Sulphur is present in coking coal in organic and inorganic
bond. During coking, a part of this sulphur remains in the coke and
the remainder reaches the coal-eonstituent processing plants together
with the vapors and gases from distillation* The sulphur content of
coking coal from the Ruhr and of the coke produced from it, is
approximately within the limits listed in Table 1.
Table 1
SULPHUR CONTENT OF COAL AND COKE
FROM THE RUHR IN DRY MATTER
Constituent
Organically bonded sulphur
Bisulphides
Sulphides
Sulphates
Total sulphur
Coal
g-wt
0.7 -1.1
0,2 -0.5
-
0.01-0,05
0,9 -1.6
Coke
£-wt
O.li -0.6
-
0,3 -0.6
0.01-0,03
0,7 -1.2
The greater part of the sulphur In the coal, about 6$%9 remains
in the coke after coking. The other 3%% ar© contained in the raw gas
discharged from the coke ovens and processed in the coal-constituent
processing plants. This produces liquid products which contain about
5% of the sulphur in the coal and the remaining 30$ are gaseous
sulphur compounds.
The part of the total sulphur not remaining in the coke re-
appears as a number of different coaporaBds ia the raw gas, in the
aqueous condensates and in the liquid coal-constituents. The best
known compounds occurring are listed in Table 2.
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Table 2
SULPHUR COMPOUNDS FROM COKING
Designation
Hydrogen Sulphide
Carbon disulphide
Carbon oxysulphide
Ethyl mercaptan
Thiophene
Formula
H2S
cs2
COS
C2H5SH
w
Boiling
Point (DC)
-60
U6
-50
35
8U
Hydrogen sulphide constitutes the major part of these compounds,
By appropriate processing3 the greater part of the latter can be
recovered as elementary sulphur or as sulphuric acid.
1.3 Coke-Oven Gas;
During the coking process, about 300-ljOO Nnr of g;as are
obtained per ton of coking coalo This coke-oven gas contains hydrogen
sulphide and other sulphur-containing compounds in relatively low
concentrations,, However, in the processing of coke-oven gas and the
recovery of coal constituents, a small amount of gases with a high
concentration of hydrogen sulphide and other sulphur-containing
compounds is obtained.
Directly beyond the coke oven, coke-oven gas contains 5-13
hydrogen sulphide, in addition to carbon disulphide, carbon
oxysulphide and other organic sulphur compounds in a total amount of
about 0.5-1.3 g/NmX
During cooling of the coke-oven gas and in the scrubbing of
ammonia, a part of the sulphur-containing compounds is separated out,
together with the tar and eondensate as well as the outflow from the
washers. This share depends on the ammonia process utilized. Up to
5C# of the hydrogen sulphide are extracted during the cooling of the
gas and the scrubbing of the ammonia in coking plants operating by the
indirect process.
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Through the utilization of special processes, so-ealled partial
desulphuration, it is possible in large coke plants under certain con-
ditions to further lower the content of hydrogen sulphide. Such par-
tially desulphurated gas is utilized to an increasing degree, instead
of non-purified coke-oven gas, for bottom firing of coke ovens 'and
for supplying adjoining industrial enterprises.
When used as municipal gas or transported by pipeline, hydrogen
sulphide must be extracted completely in a desulphuration installation.
The content of non-purified, partially desulphurated and
purified coke-oven gas in hydrogen sulphide and organic-sulphur, com-
pounds is shown in Table 3,
Table 3
SULPHUR CONTENT OF COKE-OVEN GAS
Type of Gas
Non-purified
Partially desulphwated
Municipal gas or
pipeline gas
Hydrogen
Sulphide
g/Nm3
5-13
!.*-£
None
Organic
Sulphur
g/Nm3
0.5 -1.3
0,2 -0.6 v.
0,08-0.25
The processing of coke-oven gas in the coking plant takes place
in closed equipment and pipe systems. In so far as non-purified or
partially desulphurated coke-oven gas is utiliz
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L,li Gases with High Sulphur Concentration?
Wherever non-purified or partially desulphurated coke-oven gas
comes into contact with aqueous or oily condensates and with washing
media, the latter absorb hydrogen sulphide and other sulphur-con-
taining coiapounds by absorption or chemical bond. The resulting
solutions can emit sulphur-contaiiiing compounds during degasification.
In processing such solutions, a small amount of gases and vapors with
high sulphur concentration is created.
In the following, special reference is made to the particular
conditions in the various production stages„ Figures 1 to h serve
as illustration and indicate the disposition of the hydrogen sulphide.
l,i»l Condensations
The raw gas discharged from the receiver of the coke ovens
reaches the condensation precoolers at a temperature of about 80°C
which is reduced to 20°C0 In some coking plants, the cooled gas is
passed through electric precipitators to extract any remaining tar
misto Beyond such equipment ar© gas suction-pumps which draw the
coke-oven gas from the receiver and condense it to the pressure
.required for further processing. In the indirect process, the heat
of compression created by condensing the gas must be removed from the
gas in a final cooler before it is passed through!the ammonia scrubber.
In the semidirect process, the gas reaches the saturators directly
from the suction praaps.
In all of this equipmenta condensates are produced which are
collected and returned into the receiver.. The receiver condensate is
transferred to a separator tank where it separates into tar and
aqueous condensate<
Th© condensates contain hydrogen sulphide and other sulphur-
containing compounds in greatly varying concentration, depending on
the condensation conditions existing at the points where such con-
densates occuro For example, the content of hydrogen sulphide of
the aqueous condensat© is between 0,2 and 8 g/lit and that of the
weak ammonia solution in general at about 1 g/lit,
10|;2 Ammonia Scrubbers
In the indirect process, up to f>($ of the hydrogen sulphide
are extracted from the gas in the ammonia washers, in addition to
ammonia, depending on the type of construction and the operating con-
ditions of the scrubber. The outflow from the scrubber contains 2-£ g
of hydrogen sulphide per liter. In a number of coking plants, an
increased extraction of the hydrogen sulphide is achieved by the return
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of solutions containing a high degree of ammonia and a very low degree
of hydrogen sulphide to the scrubbers (ammonia-circulation scrubber).
Depending on the type of process, 60-?0£ of the hydrogen sulphide are
extracted. The outflow contains in this case 5-12 g of hydrogen sulphide
per liter.
Sulphate Plants
The ammonia is distilled with steam from the ammonia-containing
water. Together with the ammonia, the entire hydrogen sulphide is
extracted. The outflow from the stills therefore contains no hydrogen
sulphide.
The vapor mixture leaving the stills is passed through saturators
in coking plants operating under the indirect process and here the
ammonia is converted to ammonium sulphate with sulphuric acid... Vapors
escape from the saturators which contain hydrogen sulphide in hifch
concentration. They are processed either into sulphur or sulphuric
acid or are added to the coke-oven gas. In the latter case, hydrogen
sulphide is removed in a desulphuratitjn Installation or oxidized by
the heating gas.
In the senddirect recovery process without partial desulphura-
tion, the entire coke-oven gas is passed through the saturators. The
vapor mixture of the stills is added to the gas ahead of the saturators.
This again brings the hydrogen sulphide, contained in the vapor mixture,
into the coke oven gas. If, in the send-direct process, partial de-
sulphur ation of the gas is to be made>, this can be done in a manner
similar to that of the indirect process. In this case, partial de-
sulphuration is carried out prior to the entry of the gas into the
saturator.
Still and saturator are closed equipment from which hydrogen
sulphide cannot escape into the open air.
l.liU Benzol Scrubber and Benzol Plant s-t
After the extraction of the ammonia, the coke oven gas is gener-
ally led through benzol scrubbers in which the volatile hydrocarbons
are washed out with washing oil. At the same time, . the washing oil
also absorbs small amounts of hydrogen sulphide and a larger part of
the other sulphur-containing compounds from the gas (Cf; TJable 2).
In the processing of the enriched washing oil from the scrubbers, these
sulphur compounds are distilled out, together with the volatile hydro-
carbons. The raw gasoline produced in the cooling of the distillation
vapors contains the predominant share of the sulphur compounds and
the remainder is contained in the ventilation gases.
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...... cokp oven gas
._ — other g&ses &/or vapors
aqueous conJensate
snrt wash-ijig fluids
f>i~,^f.^.:t:', scrubber
."0:id'.'asation cut f low
* of hydrogen sulphide
in raw gas
final "1*3 gasoline
cooler ~crubber t-crubber!
gas
eooler
JB--4-5
r . _'l_._aj« I
^^
.-.tail
li
-------
from ooke ovens
""gg~>
I I receiver
I
coke oven gas
other gases a/or vapors
—— aqueous oondensste
and washing fluids
X of hydrogen sulphide
in raw gas
HH,/H_S _.
3 2 gaselia*
gaa pnrifieatioa
Bolpbtnrio aoid
astallatioa
Figure 2.
hydrogen sulphide in coal-ecnvtlt
is of a coking plant with
process and vLth partial deaxQptaaration.
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coke oven g&s
Citbt-:.? gnees S./ov
2; of hydrogoR sulphide
.gas
i
s
I
aqueous
condensate
(waste
water
still
water I raw
gasoline
Figure 3. tfytrogen atilphtvie in coal-constttt»ni proc»«i1ng
iiaitallati.«>n of a coidng plant- Witih sflrml-dlreet
process without partial desulphuratiosi.
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Coke oven gas
other gases &/or vapors
from poke Covens aqueous condensate
TO I and washing fluids
% of hydrogen sulphide
in raw gas
final
ifl installation
n to ' ;•••/
L
H S scrubber
Figure ).s. Hydrogen sulphide in coal-constitu«nt processing
installation of & coking plant with semi-direct
recovery process and with partial desulphuration.
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1.U5 Desulpht;ration of Gas;
Depending on the type of utilization of the coke-oven gas,
hydrogen sulphide is extracted completely or partially. This is done
by dry or wet refining processes which may be combined under certain
circumstances.
Ioii5l Dry Refining Process;
In this process, hydrogen sulphide is extracted from the coke-
oven gas completely by gas-cleaning substances such as bog-ore iron
or "Luxmasse". The sulphides so produced are oxidized by the oxygen
of the air into elementary sulphur which gradually accumulates in the
gas-cleaning substance. After an enrichment of about 1*0-50$ of sulphur,
the substance is used up and is replaced by new substance.
lol*52 Wet Refining Process s
In the wash process, the hydrogen sulphide is extracted from
the coke-oven gas in major part with the aid of washing fluids.
Depending on the washing fluid utilized, there is obtained subsequently
either elementary sulphur directly through oxidation of the sulphur
compounds or, initially, hydrogen sulphide by distillation. The
latter can be processed into sulphur or sulphuric acid.
1*1*6 Sulphur and Sulphuric-Acid Production Installations;
In such installations, the hydrogen sulphide contained in the
vapors from the saturators of the ammonium-sulphate plant as well as
from the different scrubbing processes is further processed either
into sulphur or sulphuric acid. }
In order to obtain pure sulphur, a part of the hydrogen
sulphide is oxidized. The sulphur dioxide so created is converted,
together with the non-oxidized hydrogen sulphide, in contact ovens
into sulphur and water <> The waste gases of the contact ovens which
still contain small amounts of non~converted gases, are subjected to
post-combustion with a high excess of air. Consequently, only very
small amounts of sulphur dioxide reach the open air.
For the production of sulphuric acid, hydrogen sulphide is
first oxidized into sulphur dioxidee This is converted generally
into sulphur trioad.de with the aid of catalyzers which transmit the
oxygen introduced, and finally into sulphuric acid. The waste gases
of these installations contain only small amounts of sulphur dioxide
and/or sulphur trioxide but no hydrogen sulphide. The restriction of
the emission of sulphur dioxide and sulphur trioxide by coal-constituent
processing plants is treatsd in a special VDI Specification.
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2» Measures for Reduction of Emission
2.1 General Measures:
The equipment and pipelines through which coke-oven gas and/or
gases with high concentration of hydrogen sulphide circulate, are
closed systems from which sulphur containing compounds normally cannot
escape into the open air. However, in coal-constituent plants, such
compounds may be emitted during the following occurrences:
Operational failures j
Escape of ventilating gases;
Through degasification of liquids,,
This requires very generally the following measures for the
reduction and/or prevention of emission.
Careful maintenance and control in operation must make sure
that all equipment, lines and installations are tight.
In case of operational failure, devices must exist which
prevent the gases containing hydrogen sulphide from escaping into
the open air. This may be effected, for example, by reconducting
such gases at a suitable point into the gas system of the coke plant.
Ventilatioa gases existing in current operation must be pre-
vented from constituting a risk in a similar or other manner to such
an extent that the permissible immission concentration is not exceeded.
During cleaning and repair, any waste~water containing hydrogen
sulphide must be adequately diluted, if necessary.
2.2 Special
The emission of hydrogen sulphide and other sulphur containing
compounds at various points of coal constituent processing plants
varies greatly and is dependent on the type of operation. The measures
listed below refer to the reduction of such emission.
13
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Source of Emission
Cause of Emission
Reduction of
Emission
Condensation
Unbumt gases escaping
from the gas torches
a) In normal operation
with torch shut off.
b) With torch open
during operational
failures
Gases escaping from
water seals
Outflow collectors
on coolers| collec-
tor and separator
tanks
Ammonia Scrubber
Outflow collectors
and collector
Leakage at stop valves
Failure of ignition
device
Defective seals
Gas escape from
liquids
Secondary coolers
for primary-cooler
outflow (in send-
direct process)
Benzol JBcrobbar
and Plant
Outflow receivers of
scrubbers and washing
oil tanks
Gas escape from
washing of fluid
Escape of hydrogen
sulphide with the
cooling-tower
vapors
Gas escape from
washing fluid
Careful maintenance
and care of stop
valves„
Ignition of escaping
gases at proper
time
Regular inspection
of seal level
Proper closure and
appropriate ventila-
tion of outflow
collectors and tanks
Proper closure and
appropriate
ventilation of
outflow collectors
and tanks-
Partial desulphura-
tion of the coke-
oven gas and in-
direct cooling of
outflow
Proper closure and
appropriate ventila-
tion of outflow
receivers and tanks
(continued)
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(continuation)
Source of Emission
Cause of Emission
Reduction of
Emission
Cooker-ventilating
lines
Desulphuration of
Gas
Outflow receivers
and tanks for
scrubbing fluid
Escape of sulphur-
containing compounds
with low boiling
point, together
with ventilating
gases
Gas escape from
washing fluid
Adequate cooling of
distillates and
return of ventilat-
ing gases into the
gas system of the
coke plant
Proper closure and
appropriate ventila-
tion of outflow
receivers and tanks.
3» Guidelines for the Restriction of Emission
The following conditions should be taken into consideration in
designing new coking plants.
3•! Restriction of Emission on the Basis of Immissions
Ifc the vicinity of coking plants5 the content of hydrogen
sulphide and other sulphur-containing compounds of the respiratory air
should not exceed the values established in the VDI Specifications on
Permissible Imraisaiion Concentrations for Hydrogen Sulphide.
302 Reduction of Emission by Technical Measuresg
In'addition to the points disswsed in Sec» 3d, all measures
possible under the present status of technology should be made, at
those points where emission of hydrogen sulphide and other sulphur-
eontaining eosapmrnds may occur, which are necessary to restrict or
completely prevent such emission,,
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VDI CLEAN AIR COMMITTEE SPECIFICATIONS, PUBLISHED IN ENGLISH
BY THE DIVISION OF AIR POLLUTION, U.S. PUBLIC HEALTH SERVICE
VDI No.
Title
2090 Sources of Air-Polluting Substances
2091 Restricting Dust Emission From Forced-Draft Boiler Installations,
Capacity 10 Ton/Hr and Over, Hard-Coal Fired with Mechanical
Grates
2092 Restricting Dust Emission From Forced-Draft Boiler Installations,
Capacity 30 Ton/Hr and Over, Hard Coal-Dust Fired with Dry Ash
Removal
2093 Restricting Dust Emission From Forced-Draft Boiler Installations,
Capacity 30-600 Ton/Hr and Over, Hard Coal-Dust Fired with liq-
uid Ash Removal
2094 Dust Prevention - Cement Industry
2095 Dust Emission From Induced-Draft Ore-Sintering Installations
2098 Restricting Dust Emission From Natural-Draft Steam Generators,
Capacity 25 Ton/Hr and Less, Lignite-Fired with Stationary or
Mechanical Grates ;
2099 Restricting Dust Emission in Blast-Furnace Operation
2101 Restricting Dust Emission From Copper-Ore Smelters
2102 Restricting Emission of Dust From Copper-Scrap Smelters
2103 The Restriction of Chlorine Gas Emission
2104 Terminology in Air Purification
2106 Permissible Immission Concentrations of Chlorine Gas
2107 Permissible Immission Concentrations of Hydrogen Sulphide
2108 Permissible Immission Concentrations of Sulfur Dioxide
2109 Restricting Emission of Hydrogen Sulphide and Other Sulphur-Con-
taining Compounds, Except Sulphur Dioxide, From Gas Generators
in Coke, Gas, and Coal-Constituent Processing Plants
2110 Restricting Emission of Sulphur Dioxide From Coke Ovens and Gas
Plants
2115 Restricting Emission of Dust Frc:7i Manually Operated Central-
Heating Boilers, Capacity 6CO, 000 KCAL/Hr and Less, Fired with
Solid Fuels
2281 Restricting the Emission of Fumes From Diesel-Engine Vapors
2284 Restricting Emission of Dust and culphur Dioxide in Zinc Smelters
2285 Restricting Dust and Sulphur-Dioxide Emission From Lead Smelters
2290 Restricting Emission From Gas Generators in Coke and Gas Plants
2292 Restriction of Dust Emission in Anthracite-Briquet Factories
2293 Restricting Emission of Dust in Anthracite Processing Installations
2302 Restricting Emission of Dust, Tar Mist and Gas when Charging Coke
Ovens
2105 Permissible Concentrations of Nitrous Gases
GPO B«9-«7»
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