Copy No. c^?<5' of X5c3 Copies
SULFUR RECOVERY FROM FLUE GAS
VIA
REVERSIBLE DRY ABSORBENT
Contract No. PH 22-68-40
wi th
U. S. Department of Health, Education, and Welfare
Consumer Protection and Environmental Health Service
National Air Pollution Control Administration
SUMMARY REPORT
June 20, 1968 to June 19, 1969
Gallery Chemical Company
Division of Mine Safety Appliance Company
Callery, Pennsylvania 16024
-------
ccc 69-31
SULFUR RECOVERY FROM FLUE GAS
VIA
REVERSIBLE DRY ABSORBENT
Contract No. PR 22-68-40
with
U. S. Department of Health, Education, and Welfare
Consumer Protection and Environmental Health Service
National Air Pollution Control Administration
SUMMARY REPORT
June 20, 1968 to June 19, 1969
Submitted by:
M/D. Ma/sHall
Pro J ec t^JJnemi st
Approved by
^o/c^-^-^
Project Engineer
H. W. Wilson
Manager, Process Engineering
Gallery Chemical Company
Division of Mine Safety Appliances Company
Gallery, Pennsylvania
16024
-------
. GALLERY CHEMICAL COMPANY.
ccc 69-31
SUMMARY
Under Contract PH 22-68-^0, a feasibility study was carried
out toy Gallery Chemical Company on a process for removal of sulfur
oxides from flue gas using a reversible dry absorbent.
The process concept is illustrated in Figure 1. Sulfur di-
oxide in the flue gas is first oxidized to S03 and then absorbed on a
fluidized solid. The sorbent consists of Na2S04 impregnated on an
inert carrier and takes up S03 through the formation of sodium pyro-
sulfate in accordance with the following equation:
Na2S04 + S03 ,g _ * Na2S207
A study of the oxidation of S02 was not included in the
Gallery program; however, catalytic oxidation was used to prepare an
S03 feed stream for the experimental program.
An experimental program was carried out to develop kinetic
and equilibrium data for the reaction of Na2S04 supported on silica
gel with S03. The data were obtained under conditions suitable for
a cyclic absorption and desorption process.
Using a silica carrier impregnated with about 20$ Na2S04,
absorption of S03 from simulated flue gas was found to be rapid in
the temperature range of 5^5°F to 600°F. The absorption rate was
constant up to about 70$ of sorbent capacity, with no indication of pore
-------
ccc 69-51
FIGURE 1
BASIC PROCESS FLOW DIAGRAM
I ^Alternative product kk% S02
Recycle gas
Flue gas to
electrostatic
sep. and stack
Sorbent
^
2k
r-9*
i r~
SOg
Absorption
S02
Oxidation
f
So,
rbent
Ash
Sep.
1
— ^
_T
~~» r^
SOa
Desorption
Sorb,
_ —PHP^i13^.
_J 1
m Coal
Flue gas —
from boiler
(Mech. Sep.)
Fly ash
Air
f
Absorption
Water
ro
-------
. CALLERY CHEMICAL COMPANY
ccc 69-31
diffvisional resistance. The equilibrium S03 pressure at 5^5 °F was found
to be low enough to permit removal of over 95$ of the S03 which would
result from oxidation of the S02 in flue gas. Nitrogen oxides and water
vapor in the concentration normally found in flue gas were found to have
little effect on the S03 absorption rate.
Desorption of S03 at a concentration of 6$ in the gas was
found to be very rapid at 930°F, and essentially quantitative recovery
of S03 was obtained at 1020°F.
A process design was developed based on the reaction rates and
temperature conditions determined in the experimental program. Economic
studies pointed up the importance of using an inexpensive catalyst and
sorbent and minimizing the loss of these materials. Therefore, the con-
cept of using a combined catalyst and sorbent consisting of fly ash
impregnated with V205 and NagSC^ was developed. Preliminary experiments
carried out using a fly ash based catalyst and fly ash sorbent were pro-
mising; however, time did not permit carrying these experiments to
conclusive data, and the combination catalyst-sorbent was not investi-
gated.
As shown in Figure 1, the desorbed S03 can be absorbed in sul-
furic acid to produce concentrated H2S04 or oleum for sale, or by main-
taining a slightly reducing atmosphere in the desorber, a concentrated
stream of S02 (M$) can be produced. Capital and operating costs for
recovery of sulfur oxides from flue gas were estimated with the results
shown in Table I.
-------
ccc 69-31
TABLE I
CAPITAL AND OPERATING COST SUMMARY
1^00 MW Power Plant, 0.2$ S02 in Flue Gas
Operating 330 days/year at 70$ Capacity
Concentration Sulfuric Acid
of S03 to kkjo Production
Capital Investment, $ 7,880,000 $ 10,220,000
$/KW 5.63 7-3
Operating Cost, $/year 2,590,000 3,250,000
$/ton coal 0.8l 1.01
Mil/kwh 0.33 0.42
Break even acid
sales price, $/ton H2S04 — 17. 80
-------
. CALLEFIY CHEMICAL COMPANY-
ccc 69-51
CONCLUSIONS AND RECOMMENDATIONS
It has been demonstrated that the reaction of S03 with
supported on a carrier is rapid and quantitatively reversible, and that
the equilibrium pressure of SOa increases sharply with temperature in a
range well suited to a cyclic process for recovering sulfur oxides from
flue gas. The estimated capital and operating costs, summarized in
Table I, show that the process is competitive with alternative pro-
cesses now being considered.
In areas where a market for concentrated sulfuric acid or
oleum exists the process would be especially attractive, and it is be-
lieved that a profitable recovery situation could be developed.
Potential advantages over alternative processes result from
the use of a low cost fly ash sorbent and from the relatively low re-
generation temperature, which minimizes corrosion problems.
Further study is recommended to develop a sorbent, based on
fly ash impregnated with V205 and NagSO^ which is suitable both for
oxidation of SOa and for absorption of S03, and will have physical
properties suitable for large scale gas-solid contacting.
-------
6
ccc 69-31
TABLE OF CONTENTS
SUMMARY 1
CONCLUSIONS AND RECOMMENDATIONS 5
TABLE OF CONTENTS 6
List of Illustrations 6a
List of Tables 6b
I. INTRODUCTION 7
II. EXPERIMENTAL PROGRAM 9
A. Objectives and Approach 9
B. Apparatus 10
C. Procedure 14
D. Results 17
1. Sorbent Preparation 17
2. Absorption of S03 19
a. Effect of sorbent size and gas velocity 19
b. Effect of water vapor 23
c. Effect of nitrogen oxides 25
d. Effect of temperature 28
e. Effect of Na2S04 conversion 30
f. Effect of fly ash substrate 3U
3. Desorption of S03 38
k. Fly Ash Catalyst kl
III. ECONOMIC EVALUATION kj>
A. Description of Process ^3
1. Sulfuric Acid Production 1*3
2. Concentration of SOg 45
B. Special Features 47
C. Cost Summary 48
D. Catalyst-sorbent U8
E. Converter-absorber 50
1. Description of Contactor 50
2. Depth of Sorbent Required 52
F. Desorber 55
1. Sulfuric Acid Production 55
2. Concentration of SOg 58
G. SOa Absorber 58
H. Cost Estimates 59
IV. APPENDIX 63
-------
ccc 69-31
TABLE OF CONTENTS (continued)
LIST OF ILLUSTRATIONS
Figure Page
1. BASIC PROCESS FLOW DIAGRAM 2
2. SCHEMATIC DIAGRAM OF APPARATUS 11
3. DETAIL OF SAMPLE AREA 13
k. SCHEMATIC OF REACTOR AREA FOR WATER VAPOR ADDITION 15
5- S03 ABSORPTION CURVES 21
6. EFFECT OF WATER VAPOR 2k
7. EFFECT OF NITROGEN OXIDES 26
8. EFFECT OF EQUILIBRIUM S03 PRESSURE 29
9. EQUILIBRIUM STUDIES 31
10. EQUILIBRIUM STUDIES 32
11. ABSORPTION STUDIES AT LOW S03 CONCENTRATION 33
12. S03 ABSORPTION BY FLY ASH 36
13. S03 DESORPTION FROM FLY ASH 37
Ik. DESORPTION OF S03 AT 500°C to 605°C 39
15. DESORPTION OF S03 AT 550°C kO
16. FLOW SHEET - H2S04 PRODUCTION kk
17. FLOW SHEET - S02 CONCENTRATION k6
18. CONVERTER-ABSORBER 51a
19- DECOMPOSITION PRESSURE Na2S207 53
20. S03 DESORBER 5$
-------
6b
ccc 69-31
TABLE OF CONTENTS (continued)
LIST OF TABLES
Table Page
I CAPITAL AND OPERATING COST SUMMARY 4
II SORBENT PREPARATION DATA 18
III EXPERIMENTAL CONDITIONS AND RESULTS 22
IV EXTENT OF Na2S04 CONVERSION AT 330°C 23
V EXPERIMENTAL RESULTS, RUNS 6A-6, ?A-5 and 6 2?
VI EFFECT OF TEMPERATURE ON ABSORPTION RATE 28
VII Na2S04 CONVERSION ON SILICA AND FLY ASH 35
VIII S03 RELEASE RATE AT VARIOUS TEMPERATURES 3^
IX MATERIAL BALANCE, S03 ABSORPTION-DESORPTION *H
X CAPITAL INVESTMENT, SULFURIC ACID PRODUCTION 59
XI CAPITAL INVESTMENT, CONCENTRATION OF S02 TO kty 60
XII OPERATING COST, SULFURIC ACID PRODUCTION 6l
XIII OPERATING COST, CONCENTRATION OF S02 TO kk-% 62
XIV EXPERIMENTAL DATA 63
-------
. CALLEHY CHEMICAL COMPANY.
ccc 69-31
I. INTRODUCTION
Gallery Chemical Company is developing a process for the removal
of sulfur oxides from flue gas under Contract PH 22-68-40 with the U. S.
Department of Health, Education, and Welfare, National Air Pollution Con-
trol Administration. This report summarizes the work carried out during
the contract period, June 20, 1968 to June 19, 1969.
The process is based on the use of a dry absorbent which will
catalyze the oxidation of S02 to S03, and absorb the S03 from the gas
stream. The catalyst-sorbent, which consists of Na2S04 and V2Q5 im-
pregnated on a silica substrate, absorbs S03 via the formation of sodium
pyrosulfate in accordance with the following equation:
Na2S04 + S03 »>• Na2S207
The catalyst-sorbent is regenerated by heating, and the sulfur oxides
recovered either in the form of concentrated sulfuric acid or as a con-
centrated stream of S02 gas suitable for reduction to sulfur.
The novel process concept was initially developed in an engi-
neering study carried out and funded by Gallery Chemical Company. This
study was based on experimental work previously carried out for Gallery
by Bjorksten Research Laboratories and on calculated equilibrium data.
(1) Report No. CCC-102^-TR-l4, Pyrolysis of Sodium Pyrosulfate,
Bjorksten Research Laboratories, 3/25/5U.
-------
8
CALLERY CHEMICAL COMPANY
ccc 69-51
The catalytic oxidation of SOa to SOa is being studied by others^
and investigation of this part of the process was not included in the Gallery
program. Gallery utilized this reaction in the experimental program as
means of obtaining a stream of SOa °f known concentration, and a preliminary
experiment was carried out to show the feasibility of the combined catalyst-.
sorbent concept.
-------
9
CALLEftY CHEMICAL COMPANY
ccc 69-31
II. EXPERIMENTAL PROGRAM
A. Objectives and Approach
The objectives of the experimental program were to,
- demonstrate the reversible reaction of S03 with sodium sulfate im-
pregnated on a silica-alumina support
- determine equilibrium and rate data, and absorption capacity under
conditions suitable for a continuous process for removing S02
from flue gas
- determine the effects of other flue gas components
- consider the use of sulfates other than Na2S04.
Sulfates other than Na2S04 were not investigated experimentally
because the relatively inexpensive sodium sulfate was found to be satis-
factory. Potassium sulfate reacts with SOa to form a pyrosulfate; however,
the lower melting point and higher decomposition temperature of KaSgOr
make this reaction less suitable for the process. Calcium and iron sul-
fates do not react with SOa under the process conditions.
The absorption and desorption phases of the program were studied
concurrently. Two methods were tried. The first, which was unsuccessful,
consisted of following the rate of absorption of S03 by the NaaSp4 in-
directly by monitoring the unabsorbed S03. This was accomplished by scrub-
bing the effluent from the reactor over set time intervals and calculating
the difference from established feed rates. This technique had two basic
-------
.CALLEBY CHEMICAL COMPANY ==-
ccc 69-31
problems. In spite of considerable effort we were never able to establish
a consistently accurate method of feeding gaseous S03 into the diluent
nitrogen, and the effluent scrubbing technique made it necessary to make
long experimental runs with large samples in order to get enough data points.
The second method worked exceptionally well. The S03 takeup was
measured directly by weight gain of the sample. The feed stream was pre-
pared by passing a pre-set SOa-Ng mixture and oxygen through a catalytic
converter to produce SOs. The resultant stream was passed through a bed, of the
NaaSC^-impregnated silica, and the sample periodically weighed. The re-
lease of SOa was followed in the same manner.
This second method was the source of all the rate data developed
for the program for both the absorption and desorption phases. The appara-
tus and technique for this method, therefore, will be covered in detail.
B. Apparatus
A sketch of the apparatus for following the absorption and de-
sorption of S03 by the sorbent is shown schematically in Figure 2. The
basic construction was stainless steel except for the scrubber area, where
glass was employed. Globe valves were used except for gas metering where
one degree angle stainless steel metering valves were employed. The re-
actor, sample holder and converter were all of stainless steel construction.
The basic SOg feed stock was purchased from Scientific Gas Pro-
ducts, Inc. Two feed stocks were used. One contained 2050 ppm SOg in
-------
ccc 69-31
FIGURE 2
SCHEMATIC DIAGRAM OF APPARATUS
0
o
1 1 1 1 1 1 1 1
Gram-atic
Balance
<:
,
o
— i
To
Stack
* Mine Safety Appliance Co
SQ2 Analyzer
Converter
D
D
Gas Scrubbers
J7h
Gas Scrubbers
To Stack
Wet Test
Meter
To Stack
West Test
Meter
-------
12
.CALLERY CHEMICAL COMPANY .
ccc 69-31
nitrogen. The other contained 3100 ppm S02 and 500 ppm NO in nitrogen.
Oxygen for the conversion of SOg to SOa was added to the stream after first
having been dried through a bed of 13X molecular sieve. Rotameters were
used to monitor an. gas streams.
The converter for SOa oxidation consisted of an 18 inch section
of one inch O.D. stainless steel tube packed about one-half full of stain-
less steel Raschig rings for heat transfer, and containing about 20 grams
of Harshaw KgO-activated Va05 catalyst. The converter was controlled at
450°C with a tube furnace during operation.
The reactor was constructed of a 22 inch section of 1/2 inch
schedule 40 stainless pipe and a 16 inch section of 1-1/4 inch O.D. thin-
wall stainless pipe welded together at the basket holder. The 1/2 inch
Schedule 4-0 pipe served as a preheat area for the feed stream. The 1-1/4
inch O.D. pipe allowed for insertion of sample holder and contact-free
weighing.
Detail of the sample area is shown in Figure J. The sample bas-
ket consisted of a short length of one-half inch stainless tubing with a
stainless steel screen base, and was attached by a fine platinum wire which
passed through a threaded cap to a modified Mettler balance. The basket
was suspended from the balance during weighings, but when in the absorption
or desorption phase, it was at rest on the basket holder. The basket holder
was constructed so that the sample basket, when at rest, would completely
cover the reagent gas opening. AH of the reagent or sweep gas, therefore,
-------
13
ccc 69-31
FIGURE 3
DETAIL OF SAMPLE AREA - FULL SCALE
1-lA O.D. x 1-1/8 I.D
Thin Wall Pipe
Basket Holder
1/2" Sch. 40 Pipe
Fine Platinum Wire
Basket
Wire Screen
Thermocouple
-------
Ik
. CALLERY CHEMICAL COMPANY
ccc 69-31
has to pass through the sample bed. A thermocouple monitored the reagent gas
temperature at a point about one cm below the basket. This value was con-
sidered to be the sample temperature.
The reactor area was modified as shown in Figure k to introduce
water vapor into the feed stream. Nitrogen, at a rate of 115 cc/min was
passed through water held at 77°C, and this mixture introduced into the
SOs^Ng stream at a point about k inches into the preheat zone, and about
10 inches below the sample. Lines from the converter and the water vapor
source were heated to prevent condensation.
The gas scrubbers were two banks of four glass traps equipped
with medium fritt gas dispersers. The base sections were removable for
easy replacement of scrubbing solution and were approximately 250 cc in
volume.
C. Procedure
The general procedure for following the absorption of S03 on
the sorbent was as follows: A known weight of sorbent containing Na2S04
was charged into the sample holder and lowered into the reactor to the
rest position. The sample sizes and weights varied. In the initial ex-
periments using the direct weight method, sample weights of about 1.8 g of
3 to 8 mesh material were used. In later experiments, 0-^ g samples of
10 to 16 mesh material were employed.
The sample was heated to the desired temperature and swept with
-------
15
FIGURE k
SCHEMATIC OF REACTOR AREA FOR WATER VAPOR ADDITION
To Stack
Atmospheric
Vapor Trap
2" Double Tough
Pyrex Pipe
Temperature
Control
S02
Converter
Heater
Fisher-Porter
500 cc
Magnets
-------
. CALLERY CHEMICAL COMPANY _
ccc 69-31
dry nitrogen to constant weight. While this was in progress, the converter
efficiency was measured by passing the feed stock and oxygen (ca 2 mole per-
cent) through the converter and passing the effluent through the scrubbers
for a set period of time. The first two scrubbers contained 150 mis of a
20$ water-in isopropanol solution to remove SOa as HsS04. The third scrubber
contained 150 ml of a 0.02N iodine solution to measure unconverted S0£) and
the fourth a NaaSgOa solution to catch iodine swept over from the third trap.
The conversion efficiency was taken as the amount of SOa produced as mea-
sured by acid content of traps one and two (S03 *= 2H ) divided by the total
S02 charged, as calculated from the flow rate and SOa feed stock concentration.
The unconverted SOa value from traps three and four were used as a check on
the total S02 fed.
Immediately following the converter efficiency determination the
sample stream was passed through the heated sample at 930-9^0 cc/min. At
intervals, the sample flow was diverted to the stack, and the sample sus-
pended from the balance and weighed. At the conclusion of the run the SOa
converter efficiency was again measured.
Desorption was carried out similarly, using only nitrogen as a
sweep gas at 200 cc/min. The loaded sorbent sample was rapidly heated to
the desired desorption temperature and the nitrogen passed through the bed
to sweep out SOa released. Again, the sweep gas was periodically diverted
and the charge weighed to determine weight loss.
-------
.CALLERY CHEMICAL COMPANY '
ccc 69-31
Do Results
1. Sorbent Preparation
Initial sorbent studies were limited to the preparation of a
sorbent which would be representative and readily duplicated for use in
studying the process variables. Three carrier samples were furnished by
the Davison Chemical Division, W. R. Grace and Company, and were identi-
fied as follows:
Silica Gel, grade 59 (3 - 8 mesh)
Grade 5^2 beads
Silica alumina, grade 979 (3/16 inch pellets)
Sorbents were prepared by impregnating these carriers with
dissolved in water. Impregnated samples were filtered and dried at 120°C
for 16 hours. Drying times greater than 16 hours at 120°C did not result
in further weight loss.
The results of initial experiments are shown in Table II. In
series B through E, the carriers were first washed with distilled water,
then dried at 120°C prior to being placed in the impregnating solution.
In series C, the carriers were evacuated for one hour prior to addition of
the solution to the evacuated reactor. In series D and E, the carriers
were added to the boiling saturated solution, boiled for 15 minutes, then
cooled to ambient temperature for the period shown and dried.
It was found that impregnation in the range of 20$ by weight of
Na2S04 could be achieved simply using a 2.8N Na2S04 solution at J00C with
-------
ccc 69-31
TABLE II
SQRBENT PREPARATION DATA
Impregnating Conditions Weight Gain Weight
Series Carrier Impregnating Solution Carrier Sol'n Temp. Immersion Time per gram
_ _ (cone, of NagSCU) Preparation (ac) (hours ) Carrier
B Silica Gel (59) 2.8 N washed, 30 k .25 19
Beads (5^2) 2.8 N dried at 120° 30 k .10 9-2
Pellets (979) 2.8 N 30 k .20 16.5
C Silica Gel (59) 2.8 N washed, dried at 120° 30 2 .Ik 12
Beads (5^2) 2.8 N evacuated 30 2 .029 2.8
Pellets (979) 2.8 N 30 2 .20 17
D Beads (5^2) sat. washed, 100-30 .25 - 2 .09 8.5
Pellets (979) sat. dried at 120° 100-30 .25-2 .26 21
E Silica Gel (59) sat. washed, 100-30 .25 - 20 .21 17-5
Beads (5^2) sat. dried at 120° 100-30 .25-20 .06 5.5
Pellets (979) sat. 100-30 .25 - 20 .21 17
Bulk Density
g/cc«
Silica Gel (59) 0.32
Beads (5^2) 0.5^
Pellets (979) 0.3^
* Bulk density measured in 1/2" ID tube
oo
-------
19
.CALLERY CHEMICAL COMPANY —
ccc 69-31
either the silica gel or the silica alumina. Silica gel sorbent was
selected for the experimental program.
It was hoped that other substrates could be investigated based
on the results of experimental and economics studies. However, only a
preliminary experiment using fly ash substrate was possible within the
contract period.
2. Absorption of S03
a. Effect of sorbent size and gas velocity
Typical data for the absorption of S03 on Na2S04 sorbent
are plotted on Figure 5. The experiments are identified by a 3-^character
run number. The first number indicates the sorbent charge; the letter A
or D indicates absorption or desorption, and the last number indicates the
cycle for the particular charge. Thus, run number 2A-3 is the third ab-
sorption step for sorbent charge number 2.
Initial experiments using the direct weight method were run
with a 0.5 inch diameter reactor and a sample weight of about 1.7 grams.
The 2A absorption series is representative of this operation, and the ex-
perimental conditions and results are listed in Table 3 for run 2A-^.
Absorption of S03 in this series is limited because the S03 concentration
in the outlet gas is essentially in equilibrium with the S03 pressure over
Na2Sa07.
In order to reduce the amount of S03 absorbed, the 0.5 inch
-------
20
. CALt-ERY CHEMICAL COMPANY
ccc 69-51
reactor vas replaced with a 0.25 inch diameter reactor and the sorbent
charge reduced to about O.k grams while maintaining the same gas flow.
The sorbent size was reduced to 10-16 mesh for use in the smaller reactor.
Run 6A-2 is representative of this condition, and the results are plotted
on Figure 5 and listed in Table III for comparison with Run 2A-U.
Using the smaller diameter reactor, the absorption rate was
essentially constant up to 67$ of the capacity of the sorbent, and during
this constant rate period, about 40$ of the SOa fed was absorbed. As a
result of the higher mass velocity of the gas, the calculated drop in SOa
pressure from gas phase to particle surface was reduced by about 60$, when
compared with run 2A-^.
Absorption rates have been correlated based on a driving
force equal to the difference between the average S03 pressure and the
equilibrium SOa pressure, (Y-Ye). Thus, the absorption rate constant,
k = Ibs SOa absorbed _
hour x Ib sorbent x (Y-Ye)
For this evaluation it was assumed that the absorption rate
was constant throughout the operating range of sorbent capacity; that is,
that the rate did not vary with the extent of NaaS04 conversion to NagSaOy.
However, there is some evidence (discussed in Section e) that a solid so-
lution is formed; and that the equilibrium SOa pressure varies with the
extent of Na2S04 conversion. This small effect is masked in runs such as
6A-2 in which the S03 pressure in the gas is appreciably higher than
equilibrium.
-------
ccc 69-31
6A.-2, 330°C
FIGURE 5
S03 ABSORPTION CURVES
10 20 30
50 60 70
80 90 100 no 120 130 iko 150
Time, minutes
160 170 180 190
P
-------
22
ccc 69-31
TABLE III
EXPERIMENTAL CONDITIONS AND RESULTS
Run No. 2A-U 6A-2
Temperature, °C 330 330
Sorbent size, mesh 3-8 10-16
Sorbent weight, grams 1.7396 OA060
Weight % Na2S04 in sorbent 25 25
Gas composition, 80s, ppm (lnN2) 2050 2050
Gas flow, cm3/min. 930 930
Oxygen flow, cm3/min. 20 20
S02 conversion to S03, before, % 77 81.9
S02 conversion to S03, after, k$
Na2S04 reacted with S03, 89.9 93.1
Sorbent bed height, inches 1.68 1.57
Sorbent bed diameter, inches 0.5 0.25
Gas contact time at temp., sec. 0.16 0.037
Gas velocity, ft/sec. O.kO 3.5^
%e> Reynolds No. 16 30
NSch, Schmidt No. 1.85 1.85
G, Mass velocity, Ibs/hr x ft2 112 1*50
Calc, mass transfer rate, gas to sorbent surface
kg = JD x G/80 x Nsch '^, lb moles/hr x ft2 x atmos Q.klQ I.Ok
Outside surface of sorbent, ft2 0.082 0.03^
Calc transfer rate, gas to sorbent, lb moles/hr x atm 0.03^3 0.0356
Range of constant absorption rate, % of capacity Q-kl 0-67
Constant absorption rate, Ibs S03/hr x lb sorb. 0.106 0-33^
S03 absorbed from gas (constant rate period) % of S03 fed 67 kO
AP, gas to sorbent, atmos 0.016 x 10"2 1 x 10"4
Inlet S03 pressure at sorbent surface, atmos 0.00113 0.00158
Outlet S03 pressure at sorbent surface, atmos 0.00027 0.00090
Average S03 pressure at sorbent surface, atmos 0.00070 0.0012U
Equilibrium S03 pressure at 330°C 0.0003^ 0.0003*4-
Absorption rate constant
k = Ibs S03 abs/hr x lb sorb x (Y-Ye) 295 372
-------
23
. CALLERY CHEMICAL COMPANY
ccc 69-31
The calculated absorption rate constants as shown in Table
III are 295 and 372 for runs 2A-k- and 6A-2 respectively. Since a correction
was made for the effect of increased mass velocity, the increase results
from the smaller particle size and from improved experimental accuracy ob-
tained through reduced S03 absorption.
A comparison of the percent conversion of NaaS04 to
is shown in Table IV.
TABLE IV
EXTENT OF Na2S04 CONVERSION AT 330°C
Run No.
Mesh Size
of Sample
3-8
3-8
3-8
3-8
10-16
10-16
10-16
Na2S04
Converted %
55-8
66.7
84.6
89.9
89.1
85.0
93-1
2A-1
2A-2
2A-3
2A-U
5A-1
6A-1
6A-2
The reason for increased absorption in subsequent runs in
the 2A series is not known, but the change is minor in the 6A series.
b. Effect of water vapor
The effect of water vapor"as shown in the absorption curves
plotted in Figure 6, is to increase the total weight of S03 absorbed with
a slight increase in absorption rate. Part of the increased weight results
from water being absorbed as sulfuric acid. In run 7A-1, the water flow
-------
ccc 69-31
FIGURE 6
EFFECT OF H20 VAPOR
H20 Turned Off
-4, 330°C - H20
-5, 330°C - H20
CD D 6A-6, 300°C
0 10 20
30 4o 50 6o 70 80 90 100
Time, minutes
-------
25
.CALLERY CHEMICAL COMPANY —
ccc 69-31
was turned off, and the weight absorbed dropped sharply; however, the total
weight absorbed remained greater than in run 6A-2 in which no water vapor
was present.
c. Effect of nitrogen oxides
The introduction of nitrogen oxides did not markedly affect
the SOa absorption rate. The results are shown in Figure 1, runs 7A-5 and
7A-6, and Table V. The absorption rate constant for run 7A-6 at 330°C is
about the same as that obtained in the 6A series at this temperature.
A feed gas mixture containing SOg (3100 ppm), NO (500 ppm)
and oxygen (approximately 2$) was passed through the catalytic converter
and then mixed with R^O vapor in the pre-heat zone. The stream to the
absorber thus consisted of S03 (2300 ppm), S02 (800 ppm), NO and N02
(500 ppm combined) and E^O about T%.
-------
26
ccc 69-31
16
15
Ik
13
12
11
10
1 9
1
: a
K '
1
! «
•3
to 5
k
FIGURE 7
EFFECT OF NOx IN FLUE GAS
7A-5, 300°C,
o
7A-6, 330°C, NOx, H20
10 20 30
O 50 60 70 80 90 100
Time, minutes
-------
ccc 69-31
TABLE V
EXPERIMENTAL RESULTS
27
Rum
6A-6
7A-5
7A-6
Temp., °C
Sorbent particle size, mesh
Sorbent weight, grams
Weight % Na2S04
Mmoles Na2S04 on sorbent
Feed gas, S02 ppm
Feed gas, NOX ppm
Feed gas, H20 %
Feed gas, 02 $
S03 converter efficiency, before,
SOa converter efficiency, after,
SOa converter efficiency, average
SOa pressure, inlet, atmos
Gas flov, cm3/min.
S03 absorbed in 10 min., g/g sorb.
SOa absorbed in 10 min., grams
S03 fed in 10 min., grams
S03 absorbed, # of S03 in gas
S03 pressure, outlet, atmos
S03 pressure, average, atmos
S03 pressure, equilibrium, atmos
rate constant
Ibs S03/hr x Ib sorb x (Y-Ye)
k,
300
10-16
o.uo6o
25
0.715
2050
0
0
2
73-3
7^.0
73.7
.00151
930
0.0^5
0.0183
0.0501
36.5
. 00096
.0012U
.00015
300
10-16
0.3913
25
0.689
3050
500
7
2
67
87
77
.00235
1100
0.068
0.0265
0.0925
28.7
. 00167
. 00201
.00015
330
10-16
0.3913
25
0.689
3050
500
7
2
108
63
86
.00262
1100
0.102
0.0399
0.1030
38.8
.00160
.00211
.0003^
220
-------
28
. CALLERY CHEMICAL COMPANY
ccc 69-51
d. Effect of temperature
The effect of temperature is masked by the marked effect of
equilibrium SOa pressure as illustrated by run **A-3> Figure 8. This run
was started at 375°C, which is close to the equilibrium temperature at the
feed gas composition. The curve levelled off with a small amount of S03
absorbed. The temperature was then reduced to 325 °C, and the absorption
increased markedly to a rate comparable to other experiments carried out
at 330 °C.
The effect of temperature can be estimated by comparing
calculated absorption rate constants as shown in the following table:
TABLE VI
EFFECT OF TEMPERATURE ON ABSORPTION RATE
Absorption Rate
Temperature 300° C 330°C
Run 6A-6
7A-5 220
7A-6
6A-2 372
Average 234 338
-------
ccc 69-31
Flouftii 8
EFFECT OF EQUILIBRIUM SOa PRESSURE
Temp, reduced to 325°C
10 20 30
lo 60 70 5o 90 100 110 120 130"
Time, minutes
155 150 160 ITO 180190
-------
30
. CALLEFtY CHEMICAL COMPANY
ccc 69-31
e. Effect of NagSOA conversion
Absorption curves shown in Figure 6 for the 6A and 7A series
axe essentially straight lines throughout the operating range (0 to 60$ of
sorbent capacity), and it vas assumed for this evaluation that the absorption
rate does not vary with the extent of conversion of NaaS04 to NaaSaOy. How-
ever, in studies carried out near equilibrium conditions, it is apparent that
the equilibrium SOa pressure varies with the composition of the sorbent.
Runs 6E-1* and 6E-5, Figure 9> were carried out to study
equilibrium conditions by increasing the temperature at the end of absorption
runs while maintaining the same SOa flow. The S03 concentration was about
1700 ppm in both runs. At 375°C, equilibrium was reached at this SOa pressure
when 30-6$ of the NaaS04 had been converted. The equilibrium conversion for
run 6E-4 at 4o8°C was 19.2$. A similar effect was observed in run 5E-1,
plotted in Figure 10.
Rate and equilibrium studies at low gas concentrations were
carried out in runs 10-A-l, 2 and 3, Figure 11. Further data is needed to
define the equilibrium S03 pressure over the NaaSO^NaaSaOy solid solution.
However, the effect of the solid solution is to reduce the SOa back pressure
and facilitate absorption. It is also possible that the solid solution
facilitates the transport of SOa within the particle. This may explain the
lack of diffusional resistance encountered.
-------
31
ccc 69-31
16
151
14
13
12
11
10
19
•g
i e
H 7
9 5
to •'
FIGURE 9
EQUILIBRIUM STUDIES
803 pressure 0.0017 atntos.
330°C
360°C
373°C
6E-5, 375°C
(continuation 6A-5)
-30.6jt conversion of Na<2S04
-19.2?t conversion of
-U, Uo8°C
(continuation
10 20 30 ^0 50 60
Time, minutes
70 80
-------
ccc 69-31
0.1400
0.1300
0.1200
•H o.noo
•3
ID
K
-------
ccc 69-31
10
le
33
FIGURE 11
ABSORPTION STUDIES AT LOW S03 CONCENTRATION
X
•8 5
fi
8
•3
10A-2, 285°C, 225 ppm
10A-3, 300"C, 211 ppm
10A-3, 330°C, 211 ppm
IQA-l, 330°C, 210 ppm
10 20 JO kO 50 60 70
Time, minutes
90 100 no 120 130
-------
. GALLERY CHEMICAL COMPANY
ccc 69-51
f. Effect of fly ash substrate
A preliminary investigation was started on the use of fly
ash substrate after the importance of sorbent cost was developed in economic
studies. The limited experimental work on fly ash is quite encouraging, but
was not carried far enough to fully demonstrate feasibility. Although fly
ash has considerably less surface than silica gel, it is believed to be
suitable for sorbent use because diffusion into the particle was not found
to be a rate limiting step.
Fly ash was screened and samples treated with NasS04 solution
in order to obtain a substrate suitable as a replacement for the silica-based
material. Samples in the size ranges of 0.0^6 inches - 0.078 inches and
0.028 inches - O.OU6 inches were treated overnight with a saturated solution
of Na2S04, the mixture filtered and the residue dried at 125°C. Sulfur
analyses showed a 9-7 weight percent NaaS04 content for the 0.0^6 - 0.078
inch (10-16 mesh) fraction and a 17-0 weight percent content for the smaller
sized fraction. Retreatment of the 10-16 mesh fraction raised the NaaS04
content to 19-9 weight percent.
A sample of fly ash-based absorbent was subjected to two
cycles of S03 absorption and desorption. The sample contained 19-9 weight
percent NaaS04 absorbed on a screened sample of fly ash in the size range
of 0.0^6-0.078 inches (10-16 mesh). The Na2S04 loading was similar and the
size range identical to the previously tested silica gel-based absorbent,
allowing for a nearly direct comparison. The absorption was carried out
-------
. CALLERY CHEMICAL COMPANY 1
CCC 69-J>I
at 330°C, the desorption at 550°C. The results are shown graphically in
Figures 12 and 13-
The slopes of the nearly constant rate of pick up for the
fly ash substrate (Runs 8A-1 and 8A-2) are higher than those for the silica
substrate (Runs 6A-1 and 6A-2) which are shown for comparison. The total
weight gains in the comparison are misleading because the fly ash substrate
is more dense, and thus the reactor holds more sample. Actually, the per-
cent conversions of NaaS04 to NagSgOy for the silica substrate is signifi-
cantly higher than for the fly ash substrate (Table 7).
TABLE VII
Na2S04 CONVERSION ON SILICA AND FLY ASH
NagSO.4. Content S03 Absorbed
Run No.
6A-1
6A-2
8A-1
8A-2
Substrate
silica gel
silica gel
fly ash
fly ash
25
25
20
20
(mmoles )
0.715
0.715
1.605
1.605
(mmoles )
0.608
0.666
0.993
0.856
(% of Na2SOA)
85
93
62
53
The rapid and consistent take up of SOs right up to a sharp
cut-off indicates that nil of the available Na2S04 was rapidly converted.
The curves give no indication of a diffusion-limited absorption phase.
The desorption of S03 from the fly ash-based absorbent at
550°C was slow. Our previous experience with the silica-based absorbent
under these conditions showed the SOa to be completely removed in a matter
of minutes from the time the nitrogen sweep was initiated. In contrast,
-------
36
ccc 69=31
O.UU
O.U3
0.42
0.41
0.40
0.35
20 30
Tine (minutes)
-------
ccc 69-31
37
DESORPTION OP B03 FROM PLY ASH
BASED ABSORBENT AT 550°C
0.35
80 120 160
Time (minutes)
200
2 0
-------
38
.GALLERY CHEMICAL COMPANY
ccc 69-31
the desorption of S03 from the loaded fly ash absorbent went only to the
extent of 76$ in run 8D-1 and only k-1% in run 8D-2 in periods of two hours
or more. The data are plotted in Figure 1J.
We had expected that basic materials in fly ash would per-
manently hold up some S03, but that this effect would diminish after several
cycles. This is still believed to be a valid assumption.
3. Desorption of S03
Desorption of S03 was found to be rapid and essentially quanita-
tive. A nitrogen sweep at the rate of 200 cc/min was used to give a S03
concentration in the gas effluent of approximately 6$. At 500°C, about
88$ of the absorbed S03 was released rapidly. The remainder came off very
slowly at this temperature, but was released completely by raising the sample
temperature to 550°C.
Typical desorption curves are shown in Figures 14 and 15- The
S03 recovery data is summarized in Tables VIII and DC.
TABLE VIII
S03 RELEASE AT VARIOUS TEMPERATURES
Run No.
3D-3
2D-2
2D-3
to-2
Release Temp.
°C
500
530
5^0
550
Initial Rate S03 Release
g/min.
0.020
0.014
0.0^3
0.055
mmoles/min.
0.25
0.18
0.5^
0.69
S03 Cone.
(mole $)
2.7
2.0
6.0
7-2
-------
RUN 3D-J
(330°)
(1*85° - N2 Sweep Started)
RUN kD-2
(510°)
, C550°C - N2 Sweep Started)
(550°)
V
(605°)
FIGURE lU
THE DESORPTION OF S03 AT 200 cc/mln NITROGEN SWEEP GAS RATE
80
120
160 0
Time (minutes)
80
120
160
VQ
-------
8.660
FIGURE 15
THE DESORPTION OF S03 AT 550°C AND 200 cm3/mln NITROGEN SWEEP GAS RATE
— (530° - N2 Flov Started)
Q.kOO
200
Time, minutes
-------
. CALLERY CHEMICAL COMPANY
ccc 69-31
TABLE IX
MATERIAL BALANCE, S03 ABSORPTION AND DESORPTION
S03 Absorbed S03 Desorbed
Run No.
2D-1
2D-2
2D-3
5D-1
3D-3
UD-2
4A-3
6A-2
6A-3(with
6A-Mwith
(mmoles )
1.781
2.
-------
. CALLEKY CHEMICAL COMPANY— . .
ccc 69-31
The total charge of 33-8 g was placed in the converter tube and heated to
200°C for two hours while passing a slow flow of nitrogen for further dry-
ing. S02 (3050 ppm), NOx (500 ppm) and 02 (ca. 2%) were then started through
the converter at 450°C at a total flow of about 900 cc/min to condition the
catalyst. No misting, indicative of SOa formation, was noticeable in the
trap section after 6 hours. However, after running overnight (21 hours
total) the SOa production was considerable. Converter efficiencies were
then tested periodically with the following results:
Calibration Run No. Hrs. From Initiation Conversion %
I
2
3
k
5
6
23
25
30
32
35
37
68
13^
118
77
87
87
Pressure fluctuations because of faulty valve action probably resulted in
our high result in Run 2. Fly ash residue was swept into the valve seat.
This may have carried over into calibration Run 3- According to published
reports(2', S03 catalysts are slow to come to equilibrium, and at low
concentrations, this problem may be magnified. At any rate, the last three
runs were promising, being comparable to the results obtained under our
operating conditions with the commercial Harshaw catalyst.
(2) H. F. A. Topsoe and A. Nielsen, "The Action of Vanadium Catalyst
in the Sulfur Trioxide Synthesis".
-------
.CALLEflY CHEMICAL COMPANY
ccc 69-31
III. ECONOMIC EVALUATION
A Description of Process
1. Sulfuric Acid Production
The process flow sheet and operating conditions for removal of
S02 from flue gas and conversion to sulfuric acid are shown on Figure 16.
The process is based on the reversible reaction of S03 with sodium sulfate
to form sodium pyrosulfate according to the following reaction:
Na2S04 + S03 s± Na2S207 .
S02 in the flue gas is first oxidized to S03, and the S03 is
absorbed from the gas by reaction with Na2S04 impregnated on a fly ash
substrate. The fly ash substrate is impregnated with about 25 weight
percent Na2S04 and 5 weight percent of V205 in order that the same mater-
ial may be used for oxidation catalyst and sorbent.
The catalyst-sorbent is continuously circulated through the
fluid bed oxidation zone to an air separator where fly ash from the boiler
is removed. Ninety percent conversion of S02 to S03 has been assumed.
After passing through the oxidation zone, flue gas is cooled
from 850°F to 5^5°F by heat exchange with boiler air and passed through
two fluid absorption beds designed for removal of 95$ of the S03. Flue
gas is drawn from the converter-absorber at about 8 inch water vacuum
by an exhaust fan, and passed to an electrostatic precipator, economizer
and stack, all of which are considered to be part of the power plant.
-------
ccc 69-31
FIGURE 16
FLOW SHEET - HaSO* PRODUCTION
1400 MW Boiler, 0.2% S02 In Flue Gas
\Jfy Flue gas to
electrostatic
sep., econ.,
and stack
_\ix Flue gas
from boiler
(Mech. Sep.)
-^
t
545°F
600 °F
850°F
i
0
i
-© ©'
—
Fly ash Cat. -sorb.
1
1
1020 °F
1
r
)
Air
Recycle gas
Coal
Converter-absorber Air
85 ft x 1JO ft x 160 ft high Separator
Desorber
41 ft0 x 40 ft
S03 Absorber
30 ft 0 x 30 ft
Stream
Temp., °F
Pressure, psia
S02 M Ibs/hr
S03
,T 11
N2
C02
02
Cat.-sorb.
Fly ash
H2S04
Coal
Total
it
it
it
it
1
8so
14.7
51
8286
P5SS
5l6
354
10
11.772
2
s4s
8"H3Ovac
5.1
2.8
8286.0
2555-0
511.0
342.6
0.8-
11.703.3
3
54s
14.7
6l4
614
4
600
14.7
54
5
614
673
5
800
14.7
10
10
6
100
14.7
0.8
0.8
7
100
16.4
230
3
66
299
8
100
16.4
8.2
8.2
9
45O
15
54
230
30
8
44
366
10
2^0
14.7
66
66
4=-
-------
. CALLERY CHEMICAL. COMPANY
ccc 69-31
Sorbent, rich in S03> is air conveyed to the desorber where S03
is released at a temperature of 1020°F and at a concentration of about 6$ in
an air stream heated by direct injection of powdered coal. The sorbent is
held in the fluid desorption bed for 20 minutes to insure complete removal
of S03, and then passed down through two fluid beds where it is cooled to
"°F by contact with the desorption air stream.
At 1020°F the S03 will disproportionate partially to S02 + 02;
therefore, the S03 gas is cooled to 850°? and passed through a catalyst-
sorbent fluid bed to convert this S02 back to S03.
The S03 gas stream from the desorber is cooled to ^50°F and passed
through the S03 absorber where S03 is absorbed in a circulating stream of
concentrated sulfuric acid. Off gas containing any S02 or S03 not absorbed
is recycled back to the converter-absorber.
2. Concentration of
The possibility of using this process as a means of concentrating
S02 for subsequent reduction to sulfur was considered as a result of the
concern expressed by men in the power plant field over disposal of sulfuric
acid. The flow sheet and operating conditions for concentrating the S02
to about kk% (by volume) are shown on Figure 17.
Production of concentrated S02 is accomplished by limiting the
air flow to the desorber, thus driving the disproportionation reaction,
S03 — *• S02 + 1/2 02, to completion by removal of the oxygen to form C02.
-------
ccc 69-31
FIGURE 17
FLOW SHEET - S02 CONCENTRATION
J.H-U
_ Flue gas to
electrostatic
sep., econ.j
stack
_\i/ Flue Sas
from boiler
(Mech. sep. )
Convert
85 ft x 130
Stream
Temp., °F
Pressure, psia
S02 M Ibs/hr
S03
..... ii
N2
C02
H20
02
Cat . -sorb . "
Fly ash
Coal
Total
\J i'lH DUJ.JLC^, \J*Cf> OU2 ill rj.
-^
1 {
_5i5°l_
600 °F
_850°F
4
1
ue iraa
©
er-absorber
ft x 160 ft high
1
850
14. 7
51
8286
2555
516
154
10
11,772
2
545
8"Hr,O-vac
5.1
9 fl
8286.0
2555.0
511. 0
149.6
0.8
11,703.3
3
545
} 14.7
6l4
614
.©
^
i
—
r
1050
°F
1
<
4
i
(
(S) .
^
D
S02 (44*)^
©-
Fly ash Cat. -sorb. Air Coal
Air Desorber
Separator 18 ft 0 x 70 ft
4
600
14.7
54
5
614
673
5
800
14.7
10
10
6
100
14.7
0.8
0.8
7
100
20.7
5.3
0.1
1.5
6.9
8
100
20.7
4.6
4.6
9
1050
14.7
4^5.2
5.4
17.0
5.1
70.7
-------
CALLERY CHEMICAL. COMPANY _______
ccc 69-51
The dissociation pressure of Na2S207 reaches one atmosphere at about 12U2°F.
If all of the oxygen were removed by carbon to form C02, it should be possible
to produce a gas mixture containing 2/5 S02 and 1/5 C02. Under the design
conditions shown in Figure 17 > the S02 concentration is limited to about kk%
by water picked up by the sorbent and by the air flow needed for fluidization
and heating.
B. Special Features
The particular advantages offered by this process are summarized
as follows:
1. The reaction is rapid, reversible, and clean; that is, there are
no problems with side reactions or by-products other than sulfuric
acid.
2. The sharp change of SOa partial pressure with temperature permits
a cyclic process to operate over a narrow temperature range.
5- Sulfur in flue gas can be converted either to concentrated sulfuric
acid or a concentrated S02 stream suitable for reduction to sulfur.
k. Reducing agents are not required when producing sulfuric acid.
5. Sorbent can be regenerated at relatively low temperature.
6. Catalyst-sorbent is inexpensive and expendable. (The V205, which
represents most of the sorbent cost, could be recovered partially
from the electrostatic precipitator. This recovery was not con-
sidered in the present cost analysis.)
7. A novel, low pressure, fluid contactor has been suggested. This
-------
kd
.CALLERY CHEMICAL COMPANY —
ccc 69-51
design is believed to offer advantages for the high volume, low
pressure flue gas application.
8. Corrosion problems are minimized.
C. Cost
We can visualize problems in disposing of sulfuric acid at many,
perhaps the majority of power plant locations. However, the special case
in which a large new power plant is located near or adjacent to a sulfuric
acid consuming industry is believed to warrant consideration because this
may be the only case in which an economically attractive recovery situation
can be developed. The present trend of locating the power plant at the
mine could lead to such a situation.
Following is a summary of estimated capital and operating costs :
MW Power Plant, 0.2$ S02 in Flue Gas
Operating 330 days/year at 70$ Capacity
Concentration Sulfuric Acid
of S0g to kk% Production
Capital investment $ 7,880,000 $ 10,220,000
$/KW 5.63 7-3
Operating cost $/year 2,590,000 3,250,000
$/ton coal 0.8l 1.01
mil/kwh 0.33 0.^2
Break even acid price
$/ton H2S04 — 17.80
D. Catalyst -sorbent
Most processes for recovery of SOg from flue gas will require
a carrier for transport of the sulfur. Carrier losses, which
-------
. CALLEFIY CHEMICAL COMPANY _
ccc 69-31
necessarily result from the high gas volume and fly ash contamination,
represent a major operating cost factor. The approach we have taken is
to accept considerable loss, emphasizing a low cost granular carrier.
It is apparent that the silica gel substrate employed during
the bulk of our experimental program is better than necessary, since no
internal diffusions! resistance was observed within the operational range
of saturation. In seeking a silica-alumina substrate which would be
compatible with flue gas at elevated temperature and be available in
large volume at low cost, the advantages of fly ash became obvious.
Experimental work using fly ash was limited to preliminary ex-
periments (described in the experimental section of this report), and
conditions for making suitable catalyst-sorbent were not determined.
However, an indication of feasibility was obtained for using fly ash sub-
strate both as a catalyst and as a sorbent.
The surface area of the fly ash granules is considerably less
than that of silica gel. However, we visualize making a material with
adequate surface by incorporating a basic material such as soda ash or
lime in the impregnating solution. The basic material will react with
fly ash to form a cement like structure. We visualize carrying this im-
pregnating reaction out in a ball mill to give the desired particle size.
Assuming that this relatively simple processing operation will
yield a suitable catalyst-sorbent, the material and capital costs were
-------
. CALLERY CHEMICAL COMPANY.
ccc 69-31
50
calculated as follows:
Sorbent make up (0.1$ of feed)
614,000 Ibs/hr x 0.001 x 7920 hrs/yr
Catalyst make up (l$ of inventory/day)
20,000 ft3 x 25 lbs/ft3 x 0.01 x
3JO days/yr
Total make up
4,850,000 Ibs/yr
1,650,000 Ibs/yr
6,500,000 Ibs/yr
Material Cost
Na2S04: 6.5 x 106 x 0.25 x $0.017/lb
V205 : 6.5 x 106 x 0.05 x $1.40/lb
Total
$478,000/6.5 x 106 Ibs
Capital Cost - Processing Equipment
Est. Cost = $280,000, Installed in place.
$ 27,600/yr
450.000
$ 477,600/yr
'$ 0.0735/lb catalyst-
sorbent
Labor Cost: One operator per shift was included in process operating
cost estimate for catalyst-sorbent preparation.
It is recognized that the principal uncertainties in the recovery
process are associated with the catalyst-sorbent. These uncertainties could,
for the most part, be resolved through a relatively small experimental pro-
gram, which has been proposed.
E. Converter-Absorber
1. Description of Contactor
A fluid bed gas-solid contactor is recommended for the converter-
absorber. Fluid-bed processing is particularly well adapted to a large
scale, single line type plant. We believe that a single line plant is much
preferable to one having multiple lines of equipment in parallel, and that
savings in piping, labor, etc., will be greater than are reflected in a
factored cost estimate.
-------
51
. CALLEFIY CHEMICAL COMPANY
ccc 69-31
A somewhat novel type of low pressure contactor is proposed as
shown in Figure 18. The contactor is essentially a normal, steel frame
building with beds supported on internal columns. Approximate outside
dimensions are 85 ft x 1JO ft x 160 ft high. The building operates under
a vacuum of about 8 inches HgO created by the flue gas exhauster.
The contactor consists of four sections arranged vertically and
operating in parallel. Flue gas, flowing at a velocity of 2.5 ft/sec.,
passes through three fluid catalyst-sorbent beds in series. The lower
bed is seven inches deep and operates at 850°F to catalyze the oxidation
of S02 to S03. The next two beds, having a total fluidized depth of 7-1/2
inches, operate at 625°F and 5^5°F respectively and provide for absorption
of 95% of the S03 from the flue gas. The fluid beds are supported on 8 inch
pipes which carry air to the boiler, thus providing for temperature control
and mechanical tray support.
In the design proposed the duct work becomes part of the building.
The flow pattern is difficult to analyze, but it is assumed that sufficient
settling of solids from the gas phase occurs in the relatively low velocity
horizontal and vertical ducts to eliminate the need for a cyclone separator
ahead of the final electrostatic separator (assumed part of the power plant).
The principal advantage of this type contactor is low pressure
drop. The cost installed in place is estimated to be $2,000,000 as compared
to $2,500,000 for a conventional unit including cyclone separator. It is
believed that the low pressure, low velocity type contactor warrants further
-------
51a
ccc 69-31
FIGURE 18
CONVERTER-ABSORBER
160'
130' long
85' vide
-------
52
. CAL.LEFIY CHEMICAL. COMPANY
ccc 69-31
study; however, for the purpose of initial evaluation of process economics,
the use of a more conventional type contactor and cyclone separator would
not markedly affect the results.
2. Depth. of Sorbent Required
The depth of catalyst -sorbent required for removal of 95$ of the
SQa in the flue gas was calculated based on the experimentally determined
rate constant, and assuming that the rate is proportional to the S03 con-
centration in the gas minus the equilibrium SOa partial pressure, (Y-Ye).
The equilibrium SOa pressure was calculated based on free energy
data as follows :
Na2S207 - » Na2S04 + S03
AFf -UlO,400 -302,730-88,545, AF 298 °K = + 19,125 cal.
AHf -^55,600 -333,500 -9^50, AH 298°K = + 27,650
Cp 51-2 33.8 17 , ACp = - OA
K = Equilibrium constant = Partial pressure SOa, atmos.
log K = -AFA.575 T
K, 298°K = 0.935 x Ifc'i* atmos.
Since ACp is small, AH was assumed to be constant, and K calcu-
lated as a function of temperature by the following equation:
log/KaL AH _ (Ta - TI
¥375"
The solid line in Figure 19 shows the calculated equilibrium
partial pressure of SOa- The dashed line, which follows points determined
-------
FIGURE 19
DECOMPOSITION PRESSURE
N82S207 —+• SO 3+N32S04
Q CALCULATED
X COATS, DEAR & PENFOLD
A CCC RUN 3A-2
10
700 800
Temperature, *K
-------
CALLERY CHEMICAL COMPANY
ccc 69-31
experimentally by Coats et al' and by Gallery indicates that the equilibrium
pressure is somewhat higher than that calculated. Gallery data also indicates
that a solid solution is formed. Thus, the actual equilibrium pressure also
depends on the extent of conversion of NagSC^ to
The absorption rate was found to be constant at 0.335 Ibs S03/hr
x Ib sorbent up to about 67$ of sorbent capacity or 0.088 Ibs S03/lb sorbent.
Thus, the sorbent circulation rate required is 6l4,000 Ibs sorbent per hour
(5^,000 Ibs SOa/hr x 0.088). The depth of sorbent required was calculated
assuming that the absorption rate is a function of (Y-Ye) according to the
following equation:
G dY (MSOS/MQ) = k psf (Y-Ye) d h
dY _ Mfl k Psf h
Y-Ye " Msoa G
G = Gas mass flow rate, Ibs/hr ft2
MS 03> M(j = molecular weights of S03 and flue gas
k = absorption rate, Ibs SOa/hr x Ib sorb x (Y-Ye)
psf = fluidized density of sorbent, lbs/ft3
h = bed depth, ft.
The left hand side of the equation was integrated graphically
between the limits of Y = 0.002 and Y = 0.0001 for 95$ absorption of S03
to give a value of 5-07- Substituting an average reaction rate from ex-
perimental data, k = 310, and fluidized density, psf = 25 yields,
h = 0.00176 G.
(3) Coats, A. W., Dear, D J.A. and Penfold, D
Phase Studies on the Systems, Na2S04-S03, K2S04-S03 and Na2S04-K2S04-S03
Journal of the Institute of Fuel, March, 1968, p 129.
-------
55
. GALLERY CHEMICAL COMPANY __ _ -
ccc 69-31
At a superficial velocity of 2.5 ft /sec, the required bed area
is 34,000 ft2 and G = 3^6. At this mass velocity the required bed depth
is 0.6o8 ft = 7-3 inches. Two beds having a total depth of 7-5 inches
were selected.
F. Desorber
1. Sulfuric Acid Production
A sketch of the S03 desorption vessel required when operating
to produce sulfuric acid is shown in Figure 20. The vessel is approxi-
mately 41 ft diameter by ko ft high, and was assumed to be constructed
of low alloy, Alonized steel. A cyclone separator is provided for removal
of catalyst sorbent carried overhead.
Desorption of SOa from the sorbent has been shown to be very
rapid at 1020°F, and is accomplished in a fluid bed 6 ft deep, sized to
allow a sorbent residence time of 20 minutes. S03 is removed at a con-
centration of 6$ in air heated by direct injection of powdered coal.
After SOa removal, the sorbent passes down through two fluid beds where
it is cooled to 5^5 °F by the incoming desorption air stream.
At 1020°F S03 is partially dissociated. The extent of disso-
ciation depends on the equilibrium constant and on the oxygen concentra-
tion as shown in the following equation:
[S02] / [S03] = K/[02r
At the design conditions for sulfuric acid production the oxygen
partial pressure is about 0.1 atmosphere and the equilibrium constant is
0.0^37 at 1020°F. Inserting these figures, the [S02]/[S03] ratio = 0.138,
which indicates about 12$ dissociation.
-------
ccc 69-51
FIGURE 20
S03 DESQRBER
56
Cooling air
Sorbent irr
Coal In
Sorbent out-
Air In
r
^H^
r
Lr
1
gas to
absorber
Catalyst beds
Regeneration bed
Combustion zone
Cooling beds
(2) x 3" deep
' dlam. x Uo1 high
-------
57
. GALLERY CHEMICAL COMPANY
ccc 69-31
In order to convert the SOg back to S03 the gas stream is cooled
to 850°? and passed through a catalyst-sorbent bed formed by recycling part
of the stripped catalyst-sorbent back to the top of the desorber.
The possibility of sorbent particles sticking together has been
considered, since liquid NaaSaOy could exist at temperatures above 750°F
in the presence of a high concentration of S03. The minimum eutectic melt-
ing point in the NaaS04-Na2S207 system is 750°F at an S03 concentration of
2700 ppm. Thus, a liquid phase cannot exist in the converter-absorber unit,
but could exist vhile the sorbent is being heated to 1020°F. Slight evidence
of sticking was observed on removing the sorbent after multiple runs in the
laboratory. However, under conditions used in the laboratory, the sorbent
was heated to regeneration temperature before starting the nitrogen sweep.
During the appreciable time period required for heating, conditions con-
dusive to the formation of liquid Na2S207 would exist. In the proposed
plant design we expect to by-pass this problem by injecting the rich sorbent
into the hot vapor space above the regeneration bed, where the sorbent sur-
face should remain dry as a result of rapid evolution of S03.
The S03 concentration from the desorber was initially set at 6$
in line with sulfur burning acid plant design. However, in this process,
it is probable that a more economical design could be developed by going
to a slightly higher temperature and higher concentration. Thus, the vessel
size and power required for sorbent regeneration and S03 absorption in
H2S04 could be markedly reduced as a result of the smaller gas volume.
-------
58
. CALLERY CHEMICAL COMPANY
ccc 69-51
2. Concentration of S0g
Operation of the desorber using a limited amount of air to produce
a concentrated stream of S02 has not been tried experimentally. There would
seem to be little doubt that it is possible to promote the disproportionation
of S03 to SOg using carbon to maintain a low oxygen concentration. A tempera-
ture of 1050°F has been assumed for this evaluation, but a somewhat higher
temperature may be desirable for increased reaction rate.
The drastically reduced air flow rate results in a much smaller
desorption tower, blower and cyclone separator than are required for the
conditions assumed for acid production. The desorber is 18 ft diameter by
70 ft high.
G. S03 Absorber
The S03 absorber is an acid proof brick lined tower 30 ft diameter
by 30 ft high containing a 15 ft packed section. S03 is absorbed in sulfuric
acid which is circulated over the packing and through an external cooler at
the rate of 620 GPM.
The gas containing S03 enters the bottom of the absorber at
and the off -gas containing some S02 and S03 is recycled back to the converter-
absorber.
-------
59
ccc 69-31
H. Cost Estimates
TABLE X
CAPITAL INVESTMENT
ll*00 MW Pover Plant, 0.256 SOfe in Flue Gas
Production of Sulfuric Acid, 183,000 tons/yr
Installed Total Factor
Equip. Cost* Investment % of Total
Equipment
Converter-absorber $2,000,000
Desorber and Separator 335>000
Desorber blower 250,000
Duct work and dampers 1^0,000
Powder conveyors 130,000
Flue gas exhauster 350,000
Fines separator 120,000
Sorb -cat. prep, facility 280,000
Sorb -cat. storage 100,000
Initial sorb -cat. charge 95*000
S03 gas cooler 68,000
S03 absorber 39^,000
Acid cooler 1*5,000
Acid pumps and storage ll*6.OOP
04,1*33,000 ^,^33,000 1*3.1*1*
Instruments 29^,000 2.88
Electrical 196,000 1.92
Buildings 1*90,000 4.80
Yard Improvements 255,000 2.50
Utilities 785.000 7.69
Physical Plant Cost 6,1*53,000 63.23
Engineering and Constr. 1.293.000
Direct Plant Cost 7,71*6,000
Contractors fee 372,000
Contingency I.l60.000
Fixed Capital 9,278,000
Working Capital 91*2.000 9.10
Total Investment 010,220,000 100.00
010,220,000/1,1*00,000 KW = 07-30/KW
* Includes: Equipment, erection, foundations, piping, insulation
-------
6o
ccc 69-51
TABLE XI
CAPITAL INVESTMENT
llfOO MW Power Plant, 0.2# S02 in Flue Gas
Concentration of S02 to kk mole % Gas Stream
Installed Total Factor
Equip. Cost* Investment % of Total
Equipment
Converter-absorber $ 2,000,000
Desorber and separator 170,000
Desorber blower Uo,000
Duct work and dampers 1^0,000
Powder conveyors 130,000
Flue gas exhauster 350,000
Fines separator 120,000
Sorb.-cat. prep, facility 280,000
Sorb.-cat. storage 100,000
Initial sorb.-cat. charge 90,000
$ 3,^20,000 $ 3,^20,000 U3.UU
Instruments 227,000, 2.88
Electrical. 152,OOO' 1.92
Buildings. 378,000 ^.80
Yard improvements 197,000 2.50
Utilities 606.000 7.69
Physical Plant Cost U,980,000 63.23
Engineering and Constr. 1,000,000
Direct Plant Cost 5,980,000
Contractor fee 287,000
Contingency 895,000
Fixed Capital Cost 7<,l62,000.
Working Capital 718.000 9.10
Total Investment $ 7,880,000 100.00
$7,880,000/1,^00,000 KW = $5.63/KW
* Includes: Equipment, erection, foundations, piping, insulation
-------
61
ccc 69-31
TABLE XII
OPERATING COST
MW Power Plant, 0.2$ S02 in Flue Gas
330 Days/yr at 70$ Capacity
Production of Sulfuric Acid, 183,000 tons/yr
$/Year
Materials
Make up sorb. -cat.: 6.5 x 106 Ibs/yr x $0.0735/lb U78,000
Coal 4.08 tons/hr x 7920 x $^.00/ton 130,000
Utilities
Power 9200 KW x 7920 x $0.006/KWH ^37,000
Water 800 GPM x 60 x 7920 x $0.10/1000 gal. 38,000
Direct Labor
3 men/shift: 72 hrs/day x 365 x $3.00 8l,000
Supervision 12,000
Maintenance 5% Fixed Capital
Supplies iyf> Maintenance 69,000
Payroll burden 20$ labor and supervision 19,000
Plant overhead 50$ labor + super. + maint. + supplies 313,000
Depreciation lOjt Fixed Capital 928,000
Taxes 2# Fixed Capital 185, 000
Insurance 1# Fixed Capital 93 , OOP
Total Operating Cost $3, 2^7, 000
$/ton coal = 3.25/3.21 = $1.01
mil/KWH = 3.25 x 109/7-75 x 109 = OA2
Breakeven acid sales price
$3,2^7,000/183,000 = $17-80/ton H2S04
-------
62
ccc 69-31
TABLE XIII
OPERATING COST
1UOO MW Power Plant, 0.2$ S02 in Flue Gas
330 Days/yr at 1QJ> Capacity
Concentration of S02 to a UU# Gas Stream
$/Year
Materials
Make up sorb. -cat.: 6.5 x 106 Ibs/yr x $0.0735/lb 1*78,000
Coal 2.31 tons/hr x 7920 x $l.00/ton 73,000
Utilities
Power QlkO KW x 7920 x $0.006/KWH 387,000
Direct Labor
2 men/shift k8 hrs/day x 365 x $3.00 53,000
Supervision 7,000
Maintenance ft Fixed Capital 358,000
Supplies 15# Maintenance 53,800
Payroll Burden 20# labor and supervision 12,000
Plant Overhead 50# labor + super. + maint. + supplies 235,900
Depreciation 10# Fixed Capital 716,200
Taxes 2^ Fixed Capital 1^3,200
Insurance 1^ Fixed Capital 71 '.600
Total Operating Cost $ 2,588,700
$/ton coal = 2.59/3.21 = $0.8o6/ton coal
Mil/KWH = 2.59 x 109/7-75 x 109 = 0.335
-------
IV. APPENDIX
TABLE XIV. EXPERIMENTAL DATA
Run No.
Temperature , °C
Reactor diam. , inches
Particle size, mesh
Samples weight, grams
Na2S04, weight %
Gas flow, cm3/min.
Oxygen flow, cm3/min.
S02 converter efficiency
before, %
after, $
Gas composition (l)
S02, ppm
S03
H20
NOX
Na2S04 converted, %
S03 recovered, $
Substrate
2A-1
330
0.5
3-8
1-7396
25
930
20
28
30
2050
56
Si02
2D-1
330-605
0-5
3-8
1-7396
25
200
92
Si02
2A-2
330
0-5
3-8
1.7396
25
930
20
85
76
2050
66.7
Si02
2D-2
550
0.5
3-8
1.7396
25
200
104
Si02
2A-3
330
0.5
3-8
1-7396
25
930
20
6l
89
2050
84.6
Si02
2D-3
550
0.5
3-8
1.7396
25
200
-
96
Si02
2A-4
330
0.5
3-8
1.7396
25
930
20
77
^9
2050
89.9
Si02
3A-1
375
0.5
3-8
l . 7926
25
884
20
72
69.5
2050
26.8
Si02
3D-1
550
0.5
3-8
1.7926
25
200
94
Si02
ON
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Run No.
Temperature, °C
Reactor diam. , inches
Particle size, mesh
Samples weight, grams
Na2S04, weight %
Gas flow, cm3/min.
Oxygen flow, cm3/min.
S02 converter efficiency
before, $
after, #
Gas composition (l)
S02, ppm
S03
H20
Na2S04 converted, #
S03 recovered, %
Substrate
3A-2
375
0.5
3-8
1.7926
25
908
20
70.5
68.4
2050
15.6
Si02
3D-2
550
0.5
3-8
1.7926
25
200
173.6
Si02
3A-3
330
0.5
3-8
1.7926
25
925
20
63.6
89.0
2050
80.8
Si02
3D-3
500-550
0.5
3-8
1.7926
25
200
91.2
Si02
4A-1
300
0.5
3-8
1.8533
25
914
20
73-5
72.3
2050
36.7
Si02
4A-2
300
0.5
3-8
1.8533
25
922
20
62.8
82.0
2050
58.6
Si02
4D-2
550-600
0.5
3-8
1.8533
25
200
106
Si02
4A-5a
375
0.5
3-8
1.8533
25
938
20
54
2050
8.1
Si02
4A-3b
325
0.5
3-8
1.8533
25
938
20
5**.
2050
49.1
Si02
-------
TABLE XIV. EXPERIMENTAL DATA, (continued)
Run No.
Temperature, °C
Reactor diam. , inches
Particle size, mesh
Samples weight, grams
Na2S04, weight %
Gas flow, cm3/min.
Oxygen flow, cm3/min.
S02 converter efficiency
before, %
after, %
Gas composition (l)
S02 , ppm
S03
H20, %
NOX
Na2S04 converted, %
S03 recovered, %
Substrate
5A-1
330
0.25
10-16
0.4226(3)
25
930
20
74.5
2050
80.6
Si02
5E-1^)
Varied
0.25
10-16
0.^226(3)
25
930
20
74.5
2050
Si02
6A-1
330
0.25
10-16
o.4o6o
25
930
20
51.5
79.2
2050
85
Si02
6A-2
330
0.25
10-16
o.4o6o
25
930
20
81.9
2050
93-1
Si02
6A-3
330
0.25
10-16
o.4o6o
25
1100
20
77.3
89.8
2050
7
103.6
Si02
6A-4
330
0.25
10-16
0.4o6o
25
1100
20
89.8
83.9
2050
7
107.7
Si02
6A-5
330
0.25
10-16
o.4o6o
25
1100
20
63.2
97.8
2050
7
103.9
Si02
6E-4
406-410
0.25
10-16
0.4o6o
25
930
20
83.9
2050
19.3
Si02
6E-5
375
0.25
10-16
o.4o6o
25
930
20
63.2
97-8
2050
30.6
Si02
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Run No.
Temperature, °C
Reactor diam. , inches
Particle size, mesh
Samples weight, grams
Na2S04, weight %
Gas flow, cm3/min.
Oxygen flow, cm3/min.
S02 Converter efficiency
before, $
after,
Gas composition (l)
S02, ppm
S03
H20, %
NQx, ppm
Na2S04 converted, %
SOa recovered, %
Substrate
7A-1
300
0.25
10-16
0.3913
25
1100
20
88.8
86.2
2050
7
121
Si02
7A-2
300
0.25
10-16
0.3913
25
930
20
81.6
87.2
2050
82.4
Si02
7A-3
300
0.25
10-16
0.3913
25
1100
20
123
2050
7
111
Si02
7A-5
300
0.25
10-16
0.3913
25
1100
20
£7(0)
87(8)
3050
7
500
108
Si02
7A-6
330
0.25
10-16
0.3913
25
1100
20
._ .
108 '
63™)
3050
7
500
104
Si02
8A-1
330
0.25
10-16
0.645
19-9
900
20
96.4
96.4
3050
500
1J.2.7
Fly ash
8D-1
550-585
0.25
10-16
0.645
19.9
200
76.8
Fly ash
8A-2
330
0.25
10-16
0.645
19.9
906
20
104.8
134.5
3050
500
101.5
Fly ash
8D-2
550
0.25
10-16
0.645
19-9
200
37-5
Fly ash
ON
ON
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Run No.
Temperature , ° C
Reactor Diam. , inches
Particle size, mesh
Samples weight, grams
Na2S04, weight $
Gas flow, cm3/min.
Oxygen flow, cm3/min.
S02 Converter efficiency
before, %
after, %
Gas Composition (l)
S02, ppm
SOa, ppm
H20
NOX
Na2S04 converted, $
SOa recovered, %
Substrate
1QA-1
330
0.25
10-16
0.400
26.7
993
2
69
91.6
210
Si02
10A-2
285
0.25
10-16
0.4oo
26.7
974
2
83
225
Si02
10A-3
300
0.25
10-16
0.400
26.7
971
2
83
211
Si02
10A-4
330
0.25
10-16
o.4oo
26.7
974
2
67
225
Si02
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Run 2A-1
Time
minutes
0
6
10
15
20
25
30
35
40
^5
50
55
60
65
70
80
90
100
no
120
130
140
150
Balance
Readings
grams
8.4470
8.4572
8.4708
8.1+865
8. U927
8.5105
8.5158
8.5232
8.5286
8-5335
8.537^
8.5^18
8.5^62
8.51*90
8.5519
8.5558
8.5655
8.5699
8-5735
8.57^5
8.5770
8.5775
8.5735
Time
minutes
0
5
10
13
16
19
22
25
30
40
50
65
82
95
110
Run 2D-1
Balance
Readings
grams
8.5835
8.5761
8.5000
8.1*798
8.4775
8.4697
8.4675
8.4660
8.4630
8.4540
8.4530
8.4560
8.4530
8.4530
8.4525
Run 2A-2
Temp.
°C
330
445
570
585
590
600
Time
minutes
0
5
10
15
20
25
30
35
4o
^5
50
55
65
75
100
130
160
190
220
250
280
Balance
Readings
grams
8.4113
8.4266
8.4437
8.4539
8.4603
8.4660
8.4719
8.4768
8.4825
8.4865
8.4905
8.4990
8.5040
8.5110
8.5230
8.5352
8.5458
8.5549
8.5625
8.5692
8.5748
Time
minutes
0
15
20
27
31
N2
35
40
^5
50
55
60
70
80
90
100
120
Run 2D-2
Balance
Readings
grams
8.5895
8.5897
8.5845
8.5670
8.5560
Started
8.5040
8 . 4400
8.4355
8.4335
8.4310
8.4290
8.4265
8.4250
8.4228
8.4210
8.4195
Run 2A-3
Temp.
°C
RT
200
405
510
530
545
555
550
Time
minutes
0
5
10
15
20
25
30
40
50
60
70
80(2)
90
100
no
130
160
190
Balance
Readings
grams
8.4475
8.4675
8.4875
8.5050
8.5165
8 . 5270
8.5345
8.5455
8.5536
8.5555
8.5588
8.5588
8.5768
8.5910
8.6061
8.6240
8.6435
8.6550
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Time
minutes
0
23
30
35
N2
38
41
46
50
55
65
75
85
95
105
Run 2D-3
Balance
Readings
grams
8.6570
8.6575
8.6255
8.6096
Started
8.4920
8.4815
8.4774
8.4684
8.4699
8.4665
8.4635
8.4628
8.4620
8.4610
Temp.
°C
RT
495
525
54o
545
550
Run
Time
minutes
0
5
10
15
20
25
30
35
40
50
60
70
80
90
100
120
150
180
195
2A-4
Balance
Readings
grams
8.4582
8.4730
8.4910
8.5072
8.5230
8.5378
8.5505
8.5630
8.5732
8.5910
8.6072
8 6200
8.6305
8.6365
8.6490
8.6600
8.6693
8.6765
8.6779
Run
Time
minutes
0
5
10
20
30
40
50
60
70
80
90
100
120
130
140
150
170
190
210
240
260
280
300
3A-1
Balance
Readings
grams
8.4980
8.5014
8.5060
8 5125
8 5140
8.5215
8-5255
8.5300
8-5331
8.5360
8.5383
8.5410
8.5445
8.5455
8.5489
8 . 5500
8 5522
8.5541
8.5589
8.5602
8.5645
8 5645
8.5655
Run
Time
minutes
0
10
20
35
53
3D-1
Balance
Readings
grams
8.5780
8.5900
8.5960
8.5650
8.5430
N2 On
55
59
63
68
73
83
93
103
113
1*3
173
203
218
8.5360
8.5290
8.5250
8.5210
8.5160
8.5110
8.5095
8.5065
8.5055
8.5030
8.5020
8.5015
8.5020
Run
Time
minutes
0
5
10
15
30
45
75
90
105
120
135
3A-2
Balance
Readings
grams
8.5011
8.5030
8.5060
8.5097
8.5315
8.53^9
8-5370
8 . 5400
8.5400
8.5405
8 5405
ON
vo
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Run
Time
minutes
0
30
^
W
60
0
5
10
15
20
25
30
^5
3D-2
Balance
Readings
grams
8.5675
8.5690
8.5520
8.5390
8.5255
N2 On
8.5165
8.5102
8.5080
8 . 5050
8.5035
8.5020
8.5000
Run 3A-3
Temp . Time
°C Minutes
RT 0
150 5
365 10
485 15
525 20
550 25
30
40
50
60
70
80
110
l4o
170
200
230
260
290
305
Balance
Readings
grams
8.4990
8.5042
8.5096
8.5125
8.5143
8.5195
8.5227
8.5490
8.5698
8.5780
8.59^2
8.6035
8.6259
8.6582
8.6648
8.6749
8.6855
8.6934
8.7000
8.7028
Time
minutes
0
15
1
2
3
4
5
6
7
8
9
10
15
20
25
30
^5
55
65
70
75
85
95
105
125
Run 3D-3
Balance
Readings
grams
8.7028
8.6815
N2 On
8.6490
8.6215
8.6080
8.5855
8.5700
8.5660
8.5622
8.5550
8.5540
8.5521
8.5498
8.5481
8.5475
8.5460
8.5429
8.5415
8-5395
8.5378
8.53^3
8.5289
8.5245
8.5225
8.5172
Run 4A-1
Temp.
°C
330
485
500
500
500
500
500
500
500
500
500
500
500
500
500
500
500
.500
500
550
550
550
550
550
550
Time
minutes
0
5
10
15
20
25
37
40
50
60
70
80
90
100
110
130
160
190
210
230
250
Balance
Readings
grams
8.5540
8.5560
8.5565
8.5670
8.5715
8.5760
8.5865
8.5885
8.5940
8.6000
8.6051
8.6076
8.6115
8.6i4o
8.6170
8.6225
8.6295
8.6365
8.6401
8.6460
8.6500
Run 4A-2
Time
minutes
0
2
4
6
8
10
15
25
30
4o
50
60
70
80
100
120
l4o
160
Balance
Readings
grams
8.5467
8.5540
8.5625
8.5725
8.5802
8.5845
8.6000
8.6190
8.6255
8.6375
8.6472
8.6555
8.6610
8.6620
8.6780
8.6860
8.6923
8.7000
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Time
minutes
0
10
15
20
25
30
0
1
2
3
5
10
15
20
25
30
50
70
90
100
120
130
150
Run 4D-2
Balance
Readings
grams
8.7105
8.7095
8.6100
8.6965
8.6740
8.6^50
N2 On
8.5900
8.5825
8.5805
8.5765
8.5700
8.5635
8.5605
8.5594
8.5585
8.5525
8.5505
8.5525
8.5500
8.5490
8.5475
8.5475
Run 4A-3a
Temp.
°C
RT
160
335
^50
510
550
550
550
550
550
550
550
550
550
550
550
550
550
550
605
605
605
605
Time
minutes
0
5
10
16
20
30
40
50
60
70
Balance
Readings
grams
8.5110
8.5198
8.5250
8.5270
8.5282
8.5300
8.5321
8.5322
8.5322
8.5323
Run 4A-3b
Time
minutes
0
5
11
15
20
25
30
35
40
45
50
60
Balance
Readings
grams
8.5300
8.5414
8.5580
8.5691
8.5825
8.5940
8.6o4o
8.6150
8.6250
8.6343
8.6420
8.6585
Run
Time
minutes
0
1
2
3
4
6
8
10
12
14
16
20
24
26
28
30(3)
40
50
55
5A-1
Balance
Readings
gr&nis
0.0805
0.0825
0.0835
0.0868
0.0898
0.0950
0.1010
0.1055
0.1095
0.1135
0.1170
0.1230
0.1265
0.1275
0.1285
0.1245
0.1275
0.1285
0.1285
Run 5E-1 (4)
Time
minutes
55
60
65
70
75
80
85
95
105
H5
135
1^5
155
165
175
185
195
205
220
Balance
Readings
grams
0.1285
0.1170
0.1120
0.1080
0.1045
0.1040
0.1028
0.1010
0.0985
0.0985
0.0986
0.0965
0.0950
0.0935
0.0926
0.0920
0.0920
0.0920
0.0550
Temp.
°C
330
392
4oo
407
405
4o8
405
410
405
405
409
440
440
440
440
440
440
440
615
-------
TABLE XIV. EXPERIMENTAL DATA, (continued)
Run
Time
minutes
0
2
4
6
8
10
12
14
16
18
20
24
30
35
40
50
55
6A-1
Balance
Readings
grams
0.1120
0.1155
0.1195
0.1240
0.1292
0.1343
0.1395
0.1431
o.l46o
0.1485
0.1512
0.1545
0.1572
0.1590
0.1595
0.1605
0.1606
Run
Time
minutes
0
2
4
6
8
10
12
14
16
18
20
24
30
35
4o
50
60
6A-2
Balance
Readings
grains
0.1045
0.1075
0.1130
0.1186
0.1226
0.1271
0.1325
0.1365
0.1405
0.1431
0.1455
0.1490
0.1519
0.1535
0.1550
0.1575
0.1578
Run
Time
minutes
0
1 (5)
3 (5)
5 (5)
10
20
30
40
50
60
6A-3
Balance
Readings
grams
Oolll2
0.1110
0.1110
0.1100
0.1290
0.1380
0.1555
0.1670
0.1700
0.1705
Run
Time
minutes
0
5
10
15
21
25
30
35
40
50
60
70
6A-4
Balance
Readings
grains
0.1095
0.1135
0.1325
0.1495
0.1580
0.1635
0.1670
0.1690
0.1695
0.1700
0.1710
0.1710
Run
Time
minutes
0
5
10
15
20
25
30
35
40
45
50
55
6A-5
Balance
Readings
grams
0.1085
0.1190
0.1320
0.1395
0.1495
0.1585
0.1635
0.1660
0.1670
0.1680
0.1678
0.1680
ro
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Time
minutes
0
5
10
15
20
25
30
35
1*0
^
Run 6E-1*
Balance
Readings
grams
0.1710
0.1635
0.11*70
0.1292
0.1230
0.1227
0.1210
0.1210
0.1205
0.1205
(6)
Temp.
°C
330
360
395
408
1*08
1*08
1*08
1*08
1*08
1*08
Time
minutes
0
5
10
15
20
25
30
35
1*0
^5
50
55
Run 6E-5
Balance
Readings
grams
0.1680
0.165!*
0.1605
0.1520
0.11*50
0.1370
0.1325
0.1300
0.1200
0.1265
0.1260
0.1260
(7)
Temp.
°C
330
350
573
375
375
375
375
375
375
375
375
375
Run 7A-1
Time
minutes
0
1
3
5
6
8
10
15
20
25
30
35
1*0
1*5
50
65
95
100
105
110
H5
120
135
Balance
Readings
grams
0.0996
0.1000
0.1096
0.1205
0.1295
0.1355
0.11*20
0.1535
0.161*0
0.1655
0.1665
0.1665
H20 Off
O.l6l8
0.1617
0.1615
0.1610
0.1605
H20 On
0.1660
0.1665
H20 Off
0.1619
O.l6l7
0.1615
O.l6ll*
Run 7A-2
Time
minutes
0
2
1*
6
8
10
12
11*
16
20
30
1*0
50
60
80
120
180
Balance
Readings
grams
0.0905
0.091*8
0.1000
0.1032
0.1060
O.IOSO
0.1096
0.1115
0.1130
0.1151
0.1192
0.1225
0.1250
0.1271*
0.1298
0.1325
0.1359
Run
Time
minutes
0
2
1*
6
8
10
12
11*
16
18
20
25
30
35
1*0
50
55
60
7A-3
Balance
Readings
grams
0.0982
0.0961*
0.101*0
0.1083
o.ni*6
0.1190
0.1215
0.1250
0.1288
0.1322
0.1360
0.11*15
0.1533
0.1582
0.1595
0.1595
H2 Off
0.1555
0.1555
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Run
Time
minutes
0
2
4
6
8
10
12
14
16
20
25
30
35
55
7A-5
Balance
Readings
grams
0.0980
0.0985
0.1120
0.1150
0.1180
0.1240
0.1280
0.1325
0.1390
0.1505
0.1575
0.1576
0.1575
0.1575
Run 7A-6
Time
minutes
0
2
4
6
8
10
12
16
18
20
25
30
Balance
Readings
grams
0.0960
0.1008
0.1044
O.llSl
0.1240
0.1400
0.1451
0.1500
0.1530
0.1540
0.1535
0.1535
Run 8A-1
Time
minutes
0
2
4
6
8
12
14
16
20
25
30
35
40
45
Balance
Readings
grams
0-3511
0.3585
0.3700
0.5788
0.3855
0.4025
0.4093
0.4195
0.4252
0.4260
0.4295
0.4510
0.4520
0.4325
Run 8A-2
Time
minutes
0
2
5
7
9
11
15
20
25
30
35
40
45
50
60
65
Balance
Readings
grams
0.3675
0.3795
0.3945
0.4050
0.4120
0.4175
0.4260
0.4500
0.4520
0.4557
0.4350
0.4565
0.4570
0.4575
0.4385
0.4410
Time
minutes
0
5
30
45
60
90
105
120
150
180
210
Run 8D-1
Balance
Readings
grams
0.4325
H20 Off
0.4305
N2 On
0.4100
0.3960
0.3900
0.3815
0.3795
0.3750
0.5720
0.5710
0.5700
Temp.
°C
550
330
550
570
565
572
570
582
585
585
585
-------
TABLE XIV. EXPERIMENTAL DATA (continued)
Time
minutes
0
5
10
30
5
10
15
25
30
5
10
15
20
25
30
35
4o
50
60
70
80
90
Run 8D-2
Balance
Readings
grams
S02 On
0.4410
0.4394
0.^389
0.4360
S02 Off
0.4360
0.4350
0.4340
0.4320
0.4320
N2 On
0.4275
0.4255
0.4250
0.4225
0.4215
0.4205
0.4l8o
0.4168
0.4l4o
0.4115
0.4090
0.4085
0.4085
Run IQA-l
Temp.
°C
330
330
330
330
365
425
455
530
545
555
560
558
554
553
555
555
555
553
555
553
553
553
Time
minutes
1
6
16
21
26
31
36
41
46
51
56
61
66
71
76
81
86
91
Balance
Readings
grams
0.1235
0.1235
0.1238
0.1245
0.1245
0.1245
0.1250
0.1260
0.1273
0.1290
0.1292
0.1300
0.1300
0.1300
0.1305
0.1310
0.1310
0.1310
Run 1QA-2
Time
minutes
0
5
10
15
20
25
30
40
50
60
70
80
90
Balance
Readings
grams
0.1035
0.1062
0.1099
0.1114
0.1130
O.ll4o
0.1145
0.1161
0.1175
O.H88
0.1188
0.1200
0.1212
Time
minutes
0
5
10
15
20
25
30
35
40
50
60
70
75
85
90
95
100
105
110
120
130
135
Run 10A-3
Balance
Readings
grams
0.1030
0.1058
0.1082
0.1102
0.1106
0.1120
0.1130
0.1140
0.1146
0.1156
0.1170
0.1175
0.1184
0.1183
0.1172
0.1164
0.1160
0.1157
0.1154
0.1153
0.1150
0.1149
Run 10A-4
Temp.
°C
300
300
300
300
300
300
300
300
300
300
300
300
300
330
330
330
330
330
330
330
330
330
Time
minutes
0
5
10
20
30
4o
50
70
85
Balance
Readings
grams
0.1080
0.1070
0.1070
0.1080
0.1075
0.1070
0.1070
0.1080
O.IOSO
VJI
-------
76
. GALLERY CHEMICAL COMPANY :
TABLE XIV. EXPERIMENTAL DATA (continued)
NOTES:
1. Gas consists of N2 plus components indicated.
2. Oxygen flow to converter temporarily cut off.
3. At this point we appear to have lost a portion of sample by carry
over in the gas. A plot gives estimate of 5 mg.
k. Continuation of 5A-1.
5- Problems with SOa value.
6. Continuation of 6h.-k.
7. Continuation of 6A-5.
8. NOx interf erred with chemical analysis of trap solutions.
9- Low concentration SOa stream prepared by diluting with Na after
converter.
------- |