Sulfur Removal and Recovery from Industrial ... - ACS Publications

8 Sulfur Recovery in O i l Refineries Using IFP Processes YVES BARTHEL, ANDRE DESCHAMPS, SIGISMUND FRANKOWIAK, and PHILLIPE RENAULT

Downloaded by COLUMBIA UNIV on March 14, 2013 | http://pubs.acs.org Publication Date: April 1, 1975 | doi: 10.1021/ba-1975-0139.ch008

Institut Français du Pétrole, Rueil-Malmaison, France PIERRE BONNIFAY and JOHN W. ANDREWS Institut Franiçais du Pétrole, New York, N. Y. 10022 The IFP-1500 process converts mixed hydrogen

sulfide/sul-

fur dioxide streams to sulfur and water by a liquid-phase Claus reaction using a proprietary

catalyst.

The exit gas

from the reactor contains 1000-2000 ppm sulfur

dioxide

after incineration. Plant investment and operating costs are both relatively low, and there is no problem with corrosion. The IFP-150 process takes sulfur dioxide streams down to 150-250 ppm sulfur dioxide by ammonia scrubbing and reaction with hydrogen

sulfide-containing

gas in a scheme

similar to the IFP-1500. Nineteen IFP-1500 plants and four IFP-150 are now operating or under construction. A scheme is shown for converting all solid, liquid, and gaseous sulfur wastes in a refinery to water and sulfur, reducing

sulfur

dioxide concentration to 150—250 ppm.

V I T T h e n control of sulfur emission became an urgent concern of refineries and other plants operating on hydrocarbon feeds, a host of processes were developed on paper ( I ) .

The past 2 yrs have seen a

shakedown and thinning of these processes. O f the more than 60 originally proposed, only about half a dozen have been developed commercially. This paper concerns itself with two of those commercially proved processes developed by the French Petroleum Institute (2, 3);

one for

taking emissions down to about 1500 ppm sulfur dioxide after incineration and the other for reducing sulfur dioxide to one tenth that level. At this time 19 IFP-1500 plants are licensed as are four of the IFP-150 plants. 100

In Sulfur Removal and Recovery; Pfeiffer, J.; Advances in Chemistry; American Chemical Society: Washington, DC, 1975.

8.

BARTHEL E T AL.

The IFP-1500

Sulfur Recovery

in Oil

101

Refineries

Process

Process D e s c r i p t i o n . T h e I F P - 1 5 0 0 process is best u s e d to c l e a n u p C l a u s u n i t t a i l gas. T h e t e c h n o l o g y i n v o l v e d is essentially a n extension of t h e C l a u s r e a c t i o n itself b u t c a r r i e d out i n the l i q u i d p h a s e as s h o w n i n F i g u r e 1.

T h e t a i l gas at C l a u s u n i t exit pressure is i n j e c t e d i n t o

TREATED GAS TO INCINERATOR

TAIL GAS


FROM CLAUS PLANT

STEAM CONDENSATE

SOLVENT MAKE-UP

STEAM FOR START UP

LIQUID S U L F U R PRODUCT

Figure 1.

IFP Claus tail gas clean-up

process

the b o t t o m of a p a c k e d t o w e r w h i c h p r o v i d e s h i g h contact area b e t w e e n gaseous a n d l i q u i d phases.

T h e t o w e r is s i z e d to m a i n t a i n

d r o p w i t h i n a c c e p t a b l e l i m i t s , a v o i d i n g the n e e d for a b l o w e r .

pressure A

low

v a p o r pressure p o l y e t h y l e n e g l y c o l solvent w h i c h contains a p r o p r i e t a r y c a r b o x y l i c a c i d salt catalyst i n s o l u t i o n circulates c o u n t e r c u r r e n t the

gas.

The

catalyst forms

a complex

with

hydrogen

sulfide

to and

s u l f u r d i o x i d e w h i c h i n t u r n reacts w i t h m o r e of t h e gases to regenerate t h e catalyst a n d f o r m e l e m e n t a l sulfur. T h e r e a c t i o n is e x o t h e r m i c , a n d the heat is r e m o v e d

by

i n j e c t i n g a n d v a p o r i z i n g steam

T e m p e r a t u r e is m a i n t a i n e d a b o u t

condensate.

2 5 0 - 2 7 0 ° F , sufficient t o k e e p

the

s u l f u r m o l t e n b u t not h i g h e n o u g h to cause m u c h loss of s u l f u r or g l y c o l o v e r h e a d . T h e s u l f u r a c c u m u l a t e s i n the b o o t of t h e t o w e r a n d is d r a w n off c o n t i n u o u s l y t h r o u g h a seal l e g . P u r i t y of t h e p r o d u c t s u l f u r is v e r y g o o d as s h o w n i n T a b l e I.

O v e r h e a d s f r o m the t o w e r are sent to the


102

SULFUR

Table I.

REMOVAL

AND RECOVERY

T y p i c a l Analysis of Sulfur from IFP-1500 Claus T a i l Gas Clean-up Plants

P u r i t y (% S) H y d r o c a r b o n (ppm) A s h (ppm) Color

Design

Actual"

99.7 100 200 yellow

99.96 100 130 bright yellow

° From I F P unit serving a 270 long tons/day ( L T / D ) Claus plant. s a m e i n c i n e r a t o r u s e d to i n c i n e r a t e C l a u s t a i l gases w e r e the I F P u n i t absent.

S i n c e there is n o w a t e r b u i l d u p i n t h e I F P process, c o r r o s i o n is


no p r o b l e m .

T h e w h o l e u n i t is f a b r i c a t e d f r o m c a r b o n steel.

Sulfur Dioxide and Hydrogen Sulfide Concentration and Ratio. D e s i g n c o n v e r s i o n of I F P - 1 5 0 0 units d e p e n d s o n c o n c e n t r a t i o n of h y d r o g e n sulfide a n d s u l f u r d i o x i d e i n the C l a u s p l a n t t a i l gas a n d o n the a m o u n t of p a c k i n g i n the I F P t o w e r .

F i g u r e 2 s h o w s curves for plants

w i t h t w o different amounts of p a c k i n g .

F o r a given IFP-1500 plant,

c o n v e r s i o n varies w i t h the c o n c e n t r a t i o n of h y d r o g e n sulfide i n the f e e d . T h i s is r e s p o n s i b l e for t h e b a l a n c i n g effect w h i c h I F P - 1 5 0 0 u n i t s exert to a c e r t a i n extent o n C l a u s p l a n t o p e r a t i o n : as the C l a u s catalyst b e -


8.

BARTHEL E T AL.

Sulfur Recovery

103

in Oil Refineries

cornes spent, t h e t a i l gas contains i n c r e a s i n g l y h i g h e r concentrations of h y d r o g e n sulfide w h i c h i n t u r n increases conversions i n t h e I F P - 1 5 0 0 u n i t . F i g u r e 3 shows a c t u a l p e n traces f r o m t h e stack s u l f u r d i o x i d e m o n i tor of a r e c e n t l y c o m m i s s i o n e d I F P - 1 5 0 0 u n i t .

S u l f u r d i o x i d e at t h e

2000 PPM 1000 PPM 2000 PPM


1000 PPM 2000 PPM 1000 PPM 28

42

2000 PPM 1000 PPM 2000 PPM 1000 PPM 56

63

Figure 3.

Stack sulfur dioxide

concentration

stack m o u t h r e a c h e d as l o w as 1000 p p m u s i n g o n l y a c o n v e n t i o n a l n o n b a u x i t e catalyst i n t h e t w o stage C l a u s u n i t . F i g u r e 4 is a c o m p o s i t e of readings m a d e d u r i n g t h e start-up of t h e same p l a n t , s h o w i n g that s u l f u r d i o x i d e emissions w e r e b r o u g h t as l o w as 800 p p m . E x t r a p o l a t i n g these results to 1 0 0 % c o n v e r s i o n shows t h a t a b o u t 4 0 0 p p m s u l f u r d i o x i d e a r e left. T h i s corresponds to e q u i l i b r i u m s u l f u r a n d to c a r b o n y l sulfide a n d c a r b o n d i s u l f i d e generated i n t h e C l a u s u n i t . react i n t h e I F P - 1 5 0 0 process.

These compounds

do not

T o keep t h e m at a m i n i m u m o n e c a n r u n

the first reactor of t h e C l a u s p l a n t s o m e w h a t hotter t h a n u s u a l a n d use a n u m b e r of c o m m e r c i a l l y a v a i l a b l e catalysts ( 4 , 5 ) . T h e r a t i o of h y d r o g e n sulfide to s u l f u r d i o x i d e is e s p e c i a l l y i m p o r t a n t at h i g h conversions.

F i g u r e 5 shows a c t u a l traces f o r s u l f u r d i o x i d e ,

h y d r o g e n sulfide, a n d t h e h y d r o g e n s u l f i d e / s u l f u r d i o x i d e r a t i o f o r t h e f e e d to a n I F P - 1 5 0 0 p l a n t w i t h a d e s i g n c o n v e r s i o n of 9 0 % . F i g u r e 6 shows t h e effect of v a r y i n g t h e r a t i o o n c o n v e r s i o n f o r a p l a n t of 9 3 % d e s i g n c o n v e r s i o n . T h e d e s i g n r a t i o here is a b o u t 2.2. A r a t i o that is t o o h i g h or too l o w cuts conversions s h a r p l y . O n e that is too l o w also reduces


104

SULFUR

REMOVAL

AND RECOVERY


1900

60

65

70

75

80

85

90

95

100

CONVERSION (%) Figure 4.

Conversion vs. stack sulfur dioxide concentration for an IFP unit with 93% design conversion

the q u a l i t y of t h e p r o d u c t sulfur.

C a r e f u l c o n t r o l of the C l a u s u n i t to

m a i n t a i n p r o p e r r a t i o not o n l y o p t i m i z e s c o n v e r s i o n i n the I F P - 1 5 0 0 u n i t , b u t also i n the C l a u s p l a n t itself. Operating Factors.

A n a d v a n t a g e of the I F P - 1 5 0 0 process is its

i n s e n s i t i v i t y to changes i n gas flow rates. W h e n the first i n d u s t r i a l scale u n i t w a s s t a r t e d u p i n J a p a n , it o p e r a t e d o n flows as l o w as 3 0 % d e s i g n w i t h o u t adverse effect.

of

A n o t h e r a d v a n t a g e of the I F P - 1 5 0 0 p r o c -

ess is t h a t s t r e a m factor is l o n g , g e n e r a l l y i n t h e r a n g e of 2 yrs. A f t e r


BARTHEL E T AL.

Sulfur Recovery

105

in Oil Refineries


8.

1.8

2.0

2.2

24

2.6

2.8

3.0

3.2

34

3.6

3.8

4.0

H S / S 0 RATIO IN FEED GAS 2

Figure

6.

2

Conversion vs. H S/S0 ratio in feed gas for IFF unit with 93% design conversion 2

2


106

SULFUR

REMOVAL

AND

RECOVERY

a b o u t 24 months a s h u t d o w n is n e e d e d to w a s h a w a y catalyst w h i c h has b e e n c o n v e r t e d to sulfates a n d d e p o s i t e d o n the p a c k i n g i n the t o w e r . A s i m p l e w a s h w i t h w a t e r is u s e d .

T h e r e is n o e x t r a o r d i n a r y m a i n t e

n a n c e r e q u i r e d , a n d there is n o l a b o r n e e d e d since the C l a u s p l a n t oper ator h i m s e l f runs the I F P - 1 5 0 0 u n i t . Feed Specifications for a Two-stage 100 L T / D Claus Plant at 9 5 % Conversion

Table II.

Lb-mol/hr H S SOo Sx COS + C S Balance

8.5 4.2 1.9 0.3 879.4


2

2

Total Economics.

894.0

T a b l e I I gives specifications for f e e d f r o m a two-stage

100 L T / D C l a u s p l a n t w i t h 9 5 % c o n v e r s i o n . T a b l e I I I shows the o v e r a l l Claus +

I F P - 1 5 0 0 conversions possible for plants t r e a t i n g t a i l gas f r o m

t h a t C l a u s u n i t , w i t h I F P - 1 5 0 0 plants of v a r y i n g d e s i g n c o n v e r s i o n : 8 0 % , 7 0 % , and 6 0 % .

90%,

T a b l e I V gives i n v e s t m e n t a n d o p e r a t i n g costs

for these I F P u n i t s . It is i n t e r e s t i n g to e x a m i n e the e c o n o m i c s of the I F P - 1 5 0 0 process f r o m another p o i n t of v i e w .

Starting w i t h a

fixed

a m o u n t of

money

a v a i l a b l e for I F P p l a n t i n v e s t m e n t , one c a n d e t e r m i n e h o w m a n y c a t a l y t i c stages s h o u l d b e i n s t a l l e d i n a C l a u s p l a n t to r e a c h v a r i o u s s u l f u r d i o x i d e e m i s s i o n levels. T a b l e V shows t y p i c a l analyses for t a i l gas f r o m the

first,

second,

and third

converters

of

a 100

L T / D Claus plant.

T a b l e V I shows conversions p o s s i b l e i n a n I F P - 1 5 0 0 u n i t after t r e a t i n g Table III. Overall Recovery as a Function of IFP U n i t Design Conversion a

Feed T o t a l free a n d c o m bined S (lb-mol/hr) Overall Claus + I F P r e c o v e r y (%)

14.9 —

% IFP

Design Conversion,

HS 2

+

S0

2

90

80

70

60

1.7

2.9

4.2

5.5

99.4

99.0

98.6

98.1

« Total feed = 894.0 lb-mol/hr e a c h of these three effluent gas streams, expressed as p e r c e n t I F P c o n v e r s i o n a n d p p m s u l f u r d i o x i d e g o i n g to t h e i n c i n e r a t o r . T h e s e

figures

are b a s e d o n s p e n d i n g h a l f a m i l l i o n dollars o n the I F P - 1 5 0 0 u n i t i n e a c h case. W h e r e r e g u l a t i o n s s p e c i f y 1500-2000 p p m ( β ) , a C l a u s p l a n t m a y


8.

BARTHEL

Sulfur Recovery in Oil

ET AL.

Table IV.

107

Refineries

Investment and Operating Costs % IFP

Overall recovery Claus + I F P (%) Battery limits investment ($000) Solvent and catalyst con sumption ($/hr) Utilities Condensate (lb/hr) Power ( K W H r / h r )

Design Recovery (H S 2

S0 ) 2

90

80

70

60

99.4

99.0

98.6

98.1

510

a

+

330

1.67

280

1.65

370 21

240

1.57

320 17

1.54

280 16

250 15

Erected project cost including engineering, royalties, process data book, and solvent inventory (January 1973)


α

Table V . Analysis

Analyses of T a i l Gas 100 L T / D Claus Plant

(mol %)

Converter No. 1

H S S0 S H 0 COS CS Balance 2

2

2

2

F l o w rate ( l b - m o l / h r )

Table V I .

Converter No. 2

Converter No. 3

1.48 0.74 1.26 28.58 .02 .01 67.91

0.59 0.29 0.14 29.96 .02 .01 68.99

0.34 0.17 0.13 30.25 .02 .01 69.08

1025.27

1009.13

1007.77

Conversions Possible with Fixed $500,000 Investment in IFP Unit for a 100 L T / D Claus P l a n t 0

Treating

I F P unit conversion, H S + S0 (%) S u l f u r c o m p o u n d s to the i n c i n e r a t o r (as p p m S 0 ) Solvent and catalyst consumption ($/hr) Utilities Condensate (lb/hr) Power ( K W H r / h r ) 2

2

2

Tail Gas After

Converter No. 1

Converter No. 2

Converter No. 3

90

86

85

3000

2000

1700

1.67 400 25

1.66 180 25

° Battery limits investment including solvent inventory, 1973 basis


1.65 100 25

108

SULFUR

o n l y n e e d t w o stages.

REMOVAL

AND RECOVERY

T h i s w a s a c t u a l l y the case w h e r e a n I F P - 1 5 0 0

u n i t w a s i n s t a l l e d to c l e a n u p t a i l gas f r o m a l a r g e two-stage C l a u s p l a n t . The

IFP-150 Process T h e I F P - 1 5 0 process is b a s i c a l l y a v a r i a t i o n of t h e I F P - 1 5 0 0 process

for h a n d l i n g s u l f u r d i o x i d e streams. I n i t , t h e I F P - 1 5 0 0 process is c o u p l e d

TO STACK INCINERATOR

NH MAKE-UP,


3

AMMONIA

SCRUBBER H S-CONTAINING GAS 2

INCINERATOR

SULFITE EVAPORATOR AND SO2 REGENERATOR

TAIL GAS

SULFATE REDUCER

Figure 7.

Flow diagram of the IFP-150

to a n a m m o n i a s c r u b b i n g section.

process

W h e r e refinery s u l f u r d i o x i d e levels

m u s t b e b e l o w 200 p p m at t h e stack m o u t h , scrubbers c a n b e set u p at m a n y p o i n t s to c l e a n flue gases a n d v a r i o u s a c i d a n d sour streams. T h e effluents f r o m t h e scrubbers are t h e n p i p e d to a c e n t r a l I F P - 1 5 0 r e a c t i o n section w h e r e s u l f u r - c o n t a i n i n g c o m p o u n d s s u l f u r a n d aqueous

are c o n v e r t e d to e l e m e n t a l

a m m o n i a is r e c y c l e d to the several s c r u b b i n g sec-

tions. T h e r e is i n t e r m e d i a t e storage at several points i n the refinery so t h a t v a r i o u s units c a n operate at t h e i r o p t i m u m rates i n d e p e n d e n t

of

the o p e r a t i o n rate of the I F P - 1 5 0 r e a c t i o n section. Process Description. F i g u r e 7 shows t h e flow scheme.

T h e t a i l gas

is s c r u b b e d w i t h aqueous a m m o n i a , r e d u c i n g the s u l f u r d i o x i d e

concen-

t r a t i o n to 1 5 0 - 2 5 0 p p m . T h e c l e a n e d gas is h e a t e d a n d v e n t e d to t h e stack.

T h e b r i n e , c o n t a i n i n g m o s t l y a m m o n i u m sulfites, is h e a t e d i n a

f o r c e d - c i r c u l a t i o n e v a p o r a t o r w h e r e sulfites are d e c o m p o s e d to a m m o n i a and sulfur dioxide. 300 ° F .

T h e s e are t a k e n off o v e r h e a d w i t h w a t e r at a b o u t

B o t t o m s f r o m t h e evaporator c o n t a i n t h e r m o s t a b l e sulfates a n d

thiosulfates w h i c h are r e d u c e d a c c o r d i n g to a p r o p r i e t a r y I F P process using submerged

combustion technology

heat transfer p r o b l e m s .

to a v o i d c o r r o s i o n a n d solve

T h e r e a c t i o n is e n d o t h e r m i c a n d uses r e d u c i n g


8.

BARTHEL E T AL.

Sulfur Recovery in Oil

109

Refineries

gases p r o d u c e d b y b u r n i n g f u e l gas i n a deficiency of a i r . I n the r e d u c t i o n , sulfates a n d thiosulfates are c o n v e r t e d to a m m o n i a , s u l f u r d i o x i d e , a n d w a t e r w h i c h are m i x e d w i t h t h e o v e r h e a d s t r e a m f r o m t h e evaporator. A c i d gas or other h y d r o g e n s u l f i d e - r i c h gas a n d t h e b l e n d e d s u l f u r d i o x i d e - a m m o n i a streams are f e d to the I F P - 1 5 0 reactor at rates sufficient to m a i n t a i n a 2 : 1 r a t i o of h y d r o g e n sulfide : s u l f u r d i o x i d e . I n the reactor the h y d r o g e n sulfide a n d s u l f u r d i o x i d e dissolve i n a h i g h b o i l i n g p o i n t g l y c o l to f o r m e l e m e n t a l s u l f u r a n d w a t e r . T h e r e a c t i o n l i q u o r is m a i n t a i n e d s l i g h t l y a b o v e the m e l t i n g p o i n t of s u l f u r , as i n t h e I F P - 1 5 0 0 process, w i t h l i q u i d s u l f u r a c c u m u l a t i n g i n the b o o t of t h e t o w e r a n d b e i n g d r a w n off to storage t h r o u g h a seal l e g . Downloaded by COLUMBIA UNIV on March 14, 2013 | http://pubs.acs.org Publication Date: April 1, 1975 | doi: 10.1021/ba-1975-0139.ch008

T h e reactor t o w e r operates i n a flooded c o n d i t i o n , w i t h gases b u b b l i n g u p t h r o u g h t h e s o l u t i o n . P e r f o r a t e d trays are u s e d to i m p r o v e c o n tact.

S o l v e n t c i r c u l a t i n g c o u n t e r c u r r e n t to t h e gases is t a k e n f r o m t h e

b o t t o m of t h e t o w e r , p u m p e d t h r o u g h a steam generator a n d b a c k to the t o w e r . T h e heat of r e a c t i o n is thus r e m o v e d , w i t h steam l e a v i n g t h e generator at t w i c e a t m o s p h e r i c pressure. O v e r h e a d s f r o m t h e t o w e r are c o o l e d , a n d aqueous a m m o n i a is c o n d e n s e d

a n d r e c y c l e d b a c k to the

FURNACE GAS, CLAUS TAIL G AS, BOILER OFF-GAS RESIDUES β TARS FUEL GAS

CAUSTIC & SODI CARBONATES

ACID SLUDGE & SODIUM SULFATES CAUSTIC & SODIUM CARBONATES

+

Na / ION

— •

EXCHANGE

SOUR WATER +

Na /NH + ON EXCHANGE 4

EVAPORATOR AMMONIUM SULFATES

Figure 8.

Total sulfur recovery using IFP-150 process in a refinery

s c r u b b e r . S o m e non-condensables c o n t a i n i n g i n e r t gases, traces of s u l f u r v a p o r , a n d h y d r o g e n sulfide are i n c i n e r a t e d a n d r e c y c l e d to t h e a m m o n i a scrubber. F i g u r e 8 shows h o w t h e I F P - 1 5 0 process c a n b e i n t e g r a t e d i n t o a n o v e r a l l scheme f o r r e c o v e r i n g s u l f u r f r o m a l l gaseous, l i q u i d , a n d s o l i d s u l f u r - b e a r i n g refinery wastes.


110

SULFUR R E M O V A L A N D RECOVERY

Table VII.

T y p i c a l Performance and Economics of a 200 L T / D Claus Plant

1787 lb-mol/hr to incinerator 29.25 lb-mol/hr S compounds (as S 0 ) 250 ppm SO in treated gas 2


2

Investment Scrubbing ($) Sulfur conversion ($) Solvent inventory ($) Utilities Power ( K W H r / h r ) Circulating cooling water ( U S G P M ) Process water ( U S G P M ) M P steam (lb/hr) Chemicals L P G (lb/hr) N H (lb/hr) Solvent (S/yr)

400,000 600,000 40,000 190 1400 3 5500 220 4 4000

3

Economics.

Table VII gives

economics

for the IFP-150

process

applied to Claus unit gaseous effluent. Industrial

References

Nineteen full scale IFP-1500 units have been licensed to clean up tail gas from Claus plants: five in the U.S., one in Canada, nine in Japan, three in Russia, and one in Belgium. T h e Claus units recover from 45 to 800 L T / D of sulfur. They produce 4.3-68.7 M M S C F D of tail gas with hydrogen sulfide concentrations ranging from 3,0% 0. 9 .

(single stage) to

(three stages). Thirteen units are already in operation. Four IFP-150 units are under construction or already operating in

Japan and France. This paper was originally presented in January, 1974. A t the time of acceptance for publication, September 1974, 24 IFP-1500 plants were in operation or under construction. Literature

Cited

1. Hyne, J. B., Oil Gas J. (Aug. 1972) 70, 64-78. 2. Bonnifay, P., Dutriau, R., Frankowiak, S., Deschamps, Α., Chem. Eng. Progr. (Aug. 1972) 68, 51-52. 3. Barthel, Y., Renault, P., Bonnifay, P., Dutriau, R., Ind. Pet. Europe (431), 49-53 (1972). 4. Pearson, M . J., Hydrocarbon Process. (Feb. 1973) 52, 81-85. 5. Bryant, H . S., Oil Gas J. (Mar. 1973) 71, 70-76. 6. Engdahl, R. B., J. Air Pollut. Contr. Ass. (1973) 23, 364-375. RECEIVED June 11, 1974. Confidentiality agreements prevent disclosure of any other operating temperatures and pressures used in the IFP-1500 or IFP-150 processes.


Sulfur Removal and Recovery from Industrial ... - ACS Publications

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