Sulfur: New Sources and Uses - American Chemical Society

4 Claus Processing of Novel Acid Gas Streams

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on December 2, 2015 | http://pubs.acs.org Publication Date: March 29, 1982 | doi: 10.1021/bk-1982-0183.ch004

DAVID K. BEAVON The Ralph M . Parsons Company, Pasadena, C A 91124 B E R N A R D K O U Z E L and J O H N W. W A R D Union Oil Company of California, Brea, C A 92621

P l a n t s t o produce l o w - s u l f u r f u e l s from c o a l , oil shale, t a r sands or heavy oil f r e q u e n t l y a r e conceived t o use the Claus process t o produce byproduct sulfur. Often the p l a n t concept imposes unacceptable t e c h n i c a l burdens on the Claus s e c t i o n . This paper p o i n t s out some of the problems, and some s o l u t i o n s . In particular, the paper d i s c u s s e s a Claus type process r e c e n t l y developed with s p e c i a l a p p l i c a t i o n t o coal and oil gasification p l a n t s . The new Selectox process can achieve n i n e t y - f i v e percent conversion of hydrogen s u l f i d e even though the initial H S c o n c e n t r a t i o n is below the level p r e v i o u s l y f e a s i b l e f o r Claus p r o c e s s i n g . The e f f e c t s of v a r i o u s minor components of Claus feed are d i s c u s s e d . 2

P l a n t s to process a l t e r n a t e sources of energy w i l l make lowsulfur f u e l s from h i g h - s u l f u r feeds such as c o a l , oil s h a l e , t a r sands, o r heavy oil. Elemental sulfur w i l l be a normal byproduct. Nearly a l l processing schemes f i r s t produce H2S from the sulfur compounds in the raw m a t e r i a l , and then convert H2S t o elemental sulfur. U s u a l l y t h i s conversion step is l a b e l l e d "Claus Process". C u r r e n t l y there is great i n t e r e s t in a l t e r n a t e f u e l s manufact u r e , and p l a n t c o n f i g u r a t i o n s t u d i e s are published by the dozen. Such c o n f i g u r a t i o n s u s u a l l y i n c l u d e a "Claus process" box; a l l too o f t e n the m a t e r i a l f e d i n t o the box c o u l d not be handled by any known Claus-type process. This paper is meant t o p o i n t out some of the problems needing r e c o g n i t i o n , and some of the s o l u t i o n s . One s o l u t i o n is a new process s u i t e d t o some c o a l g a s i f i ers. Out of s e v e r a l a l t e r n a t e energy sources, c o a l has been chosen for d i s c u s s i o n in order t o s i m p l i f y what can be a very complex s u b j e c t . Coal g a s i f i c a t i o n , in p a r t i c u l a r , i n v o l v e s most of the prominent problems.

0097-6156/82/0183-0057$05.00/ 0 © 1982 American Chemical Society

In Sulfur: New Sources and Uses; Raymont, M.; ACS Symposium Series; American Chemical Society: Washington, DC, 1982.


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SULFUR:

NEW

SOURCES

AND

USES

In a c o a l g a s i f i c a t i o n p l a n t , the "Claus" u n i t is n e a r l y the l a s t in a c h a i n of process steps, and the foregoing steps can have a major e f f e c t on the Claus in a number of ways. Most of t h i s paper w i l l be examining the kind of Claus feed, but at the outset we should note that a Claus p l a n t is s e n s i t i v e to v a r i a t i o n s in feed r a t e , and that r e l a t i v e l y minor ups and downs in upstream u n i t s w i l l tend t o a m p l i f y i n t o wild f l u c t u a t i o n s in the Claus p l a n t . A c c o r d i n g l y our Claus-type p l a n t should be i n h e r e n t l y s t a b l e , i f p o s s i b l e , a b l e to r i d e through l a r g e changes in feed r a t e as w e l l as composition. This paper w i l l take note of a number of troublesome components of Claus f e e d , i n c l u d i n g o l e f i n s , C O 2 , ammonia, cyanide, and COS. Proper management of these components u s u a l l y r e q u i r e s t h o u g h t f u l s e l e c t i o n of preparatory process steps as w e l l as the Claus step i t s e l f . G a s i f i e r Products Although there are a t l e a s t a dozen kinds of c o a l g a s i f i e r s , for our purposes we w i l l d i v i d e them i n t o two types; h i g h temperature e n t r a i n e d , and low-temperature p y r o l i z e r s . Gases from the high-temperature u n i t s c o n t a i n e s s e n t i a l l y no hydrocarbons except a t r a c e of methane. In c o n t r a s t , the p y r o l i z e r s produce a range of hydrocarbons i n c l u d i n g l i g h t o l e f i n s and aromati c s , which tend t o f o l l o w hydrogen s u l f i d e i n t o Claus p l a n t feed, with u n d e s i r a b l e consequences. The gas from e i t h e r type of g a s i f i e r c o n t a i n s H 2 , CO, and CO2. About 9 5 percent of the sulfur is present as H 2 S , and the balance as COS. Other minor components i n c l u d e N H 3 and HCN. Carbon and ash are always present, and p y r o l i z e r s a l s o produce o i l s , t a r s and w a t e r - s o l u b l e o r g a n i c s . Small q u a n t i t i e s of oxygen, S O 2 , and n i t r o g e n oxides a l s o may be present. U s u a l l y the gas is water-quenched to remove s o l i d s and t a r s . Ammonia, HCN, H S d i s s o l v e in the water and high CO-content gas at h i g h pressure may produce some formic a c i d . P u r i f i c a t i o n of quench water c o n t r i b u t e s secondary Claus feeds, as w i l l be seen. 2

D i r e c t D e s u l f u r i z a t i o n of Gas Since both H 2 S and CO2 are a c i d i c , they tend to come out t o gether as mixed "acid gas" when the gas is washed t o e x t r a c t H 2 S . Various other compounds, i n c l u d i n g COS, may be extracted at the same time. E x t r a c t i o n of a c i d gas may not be needed i f the t r e a t e d gas is to be used only as f u e l ; it may be s u f f i c i e n t to t r e a t the raw gas by the S t r e t f o r d process, c o n v e r t i n g H 2 S d i r e c t l y to sulfur. Such treatment removes v i r t u a l l y a l l H 2 S but leaves COS in the f u e l gas, which may be unacceptable i f a i r p o l l u t i o n r e g u l a t i o n s r e q u i r e more than about 9 5 percent removal of t o t a l sulfur. The S t r e t f o r d process has the d e f e c t of c o n v e r t i n g a s m a l l part of the input H S to t h i o s u l f a t e , l e a d i n g e v e n t u a l l y to a 2


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Claus Processing of Novel Acid Gas Streams

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purge of s o l u t i o n from the u n i t . The U n i s u l f process, s i m i l a r t o S t r e t f o r d , has been developed to a v o i d t h i o s u l f a t e formation and e s s e n t i a l l y e l i m i n a t e purge; it is o f f e r e d by Union Science and Technology D i v i s i o n of Union Oil Company of C a l i f o r n i a . Applying the S t r e t f o r d or U n i s u l f processes u s u a l l y means there is no need f o r a Claus process. These processes are espec i a l l y s u i t e d to s m a l l a p p l i c a t i o n s where complete removal of H 2 S is s u f f i c i e n t and removal of COS is not needed.


A c i d Gas Removal Followed By Claus When the g a s i f i e d c o a l is to be used f o r s y n t h e s i s of methane, methanol, or hydrogen, p a r t or a l l of it is subjected to the water-gas s h i f t r e a c t i o n , c o n v e r t i n g CO and water to CO2 and H 2 . S u l f u r must be removed completely. The a c i d gases H 2 S and C O 2 are f i r s t e x t r a c t e d from the gas before or a f t e r the s h i f t convers i o n ; these a c i d gases may be processed in a second step in a Claus u n i t . The a c i d gas composition depends on each p a r t of the sequence preceding the Claus u n i t . The major a c i d gas component is C O 2 , which is dead weight in a Claus p l a n t but u s u a l l y makes up 80 percent to 95 percent of the a c i d gas, while most o f the remainder is H 2 S . R e l a t i v e l y more CO2 is produced from lower sulfur c o a l s , or higher temperature g a s i f i e r s , o r by s h i f t i n g before a c i d gas e x t r a c t i o n . Since p y r o l i z i n g g a s i f i e r s y i e l d o l e f i n s and aromaticsinthe raw gas, these compounds tend a l s o to occur in the a c i d gas stream. P h y s i c a l s o l v e n t processes f o r a c i d gas e x t r a c t i o n , such as c o l d methanol wash, e s p e c i a l l y tend to take hydrocarbons i n t o the a c i d gas stream; water s o l u t i o n s have l e s s tendency to do so. High C O 2 A c i d Gas The p r o p o r t i o n of C O 2 to H 2 S in Claus feed is a major f a c t o r in Claus design. I f the H 2 S c o n c e n t r a t i o n is a t a l l times 40 percent or h i g h e r , the flame in the thermal r e a c t o r is hot enough to be s e l f - s u s t a i n i n g ; complex o r g a n i c s can be converted completel y to simple gases such as COS. Tars are not formed to f o u l the c a t a l y s t and make dark sulfur. But w i t h more C O 2 in the feed, the flame temperature is inadequate to d e s t r o y complex o r g a n i c s , t a r s are formed, and the f i r e is in danger of going out. To circumvent such problems, up t o t w o - t h i r d s of the a c i d gas has been removed from the flame and sent d i r e c t l y to the c a t a l y t i c r e a c t o r , the s o - c a l l e d "long bypass" scheme. This s t r a t e g y has worked w i t h mixed success in n a t u r a l gas p l a n t s , where hydrocarbons in the a c i d gas are C 1 - C 3 p a r a f f i n s , c h i e f l y methane, and no o l e f i n s . Such a c o n f i g u r a t i o n has been put forward f o r use in c o a l g a s i f i c a t i o n p l a n t s . I n the w r i t e r ' s o p i n i o n it is unworka b l e i f the bypassed a c i d gas contains even t r a c e s of o l e f i n s or aromatics; these compounds r e a c t w i t h SO2 to form t a r r y products which f o u l the c a t a l y s t and d i s c o l o r the product sulfur.


SULFUR: NEW SOURCES A N D USES

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Thus the combination of o l e f i n s ( i n t r a c e q u a n t i t i e s ) w i t h a h i g h c o n c e n t r a t i o n of C O 2 in the acid gas may make a Claus-type process unusable. The path of l e a s t r e s i s t a n c e may be to use the S t r e t f o r d or U n i s u l f process, which t o l e r a t e both CO2 and o l e f i n s .


Enrichment of A c i d Gas An a l t e r n a t e path is two-stage e x t r a c t i o n of a c i d gas, the f i r s t stage t o separate v i r t u a l l y a l l the H 2 S in 40% concentrat i o n to feed to s t r a i g h t - t h r o u g h Claus. The second stage separ a t e s C O 2 lean enough in H 2 S to permit i n c i n e r a t i o n ; some examp l e s a p p l i c a b l e t o t r e a t i n g sour n a t u r a l gas have been published (1). U s u a l l y two d i s t i n c t a c i d gas removal p l a n t s are needed, back-to-back; these may or may not use the same e x t r a c t i o n s o l vent. To meet U.S. p o l l u t i o n standards w i t h the vented C O 2 may r e q u i r e so much co-absorption of C O 2 w i t h H 2 S that attainment of 40% H 2 S c o n c e n t r a t i o n in the f i r s t t r e a t i n g step is very c o s t l y or i m p o s s i b l e . I n any case, a c i d gas enrichment is an expensive business. P r a c t i c a l Process

Combinations

Figure 1 i l l u s t r a t e s the p r a c t i c a l combinations of known processes. With low C O 2 a c i d gas, and o n l y methane as i m p u r i t y , the c o n v e n t i o n a l Claus process may be used i f the r e a c t i o n f u r nace is designed to assure complete conversion of hydrocarbons to simple compounds such as COS and H 2 S . In another case, when the a c i d gas is very r i c h in C O 2 ( i . e . 90 percent or higher) and c o n t a i n s o l e f i n s , the author knows no s u i t a b l e process other than S t r e t f o r d o r U n i s u l f . An example is R e c t i s o l offgas downstream of a L u r g i g a s i f i e r ; the S t r e t f o r d process has been used, although w i t h some problems. As i l l u s t r a t e d in F i g u r e 1, there is another k i n d of a c i d gas which promises t o be important i n d u s t r i a l l y , i . e . h i g h C O 2 w i t h methane the only hydrocarbon. Such a c i d gas w i l l be e x t r a c t e d from c o a l g a s i f i e d in a high-temperature entrained process. O l e f i n s are not present t o form t a r r y matter b l o c k i n g c a t a l y s t and contaminating sulfur; but the normal Claus process cannot be used because H 2 S is too l e a n to support combustion. I t is the judgement of the authors that the b o r d e r l i n e f o r a p p l y i n g the convent i o n a l Claus process is an i l l - d e f i n e d area between 30 and 40 percent H 2 S , in which one needs t o c o n s i d e r the s t a b i l i t y of a l l upstream o p e r a t i o n s , the range of p o s s i b l e c o a l feeds, the s i z e of p l a n t s i n v o l v e d , and so f o r t h . A bypass type Claus p l a n t , w i t h f i r e d preheating o f a c i d gas and a i r , has been advocated by some f o r use in c o a l conversion p l a n t s , f o r a c i d gases c o n t a i n i n g 20 percent H 2 S o r l e s s . The authors t h i n k t h i s an unwise choice f o r s y n f u e l s p l a n t s , even though it can be a good choice f o r other purposes. S e v e r a l preheat-bypass Claus p l a n t s (of nominal c a p a c i t y about 1,000 tons



4.

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Figure 1. Sulfur processes for separated acid gas.


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d a i l y ) have been s t a r t e d r e c e n t l y , processing 2 0 percent H 2 S in C O 2 . These p l a n t s perform very w e l l , because of advantages which w i l l not be shared by a s y n f u e l s Claus p l a n t ; t h e i r a c i d gas has very uniform composition, and may be d i v e r t e d t o f l a r e without s e r i o u s penalty in case of upset; very cheap h i g h - q u a l i t y f u e l gas is used t o f i r e the preheaters; a complete standby Claus plant is provided; should p l a n t e f f i c i e n c y d e c l i n e , no s e r i o u s penalty would be exacted. Pleased a s we are w i t h the performance of these p l a n t s , we consider them u n s u i t a b l e f o r s y n f u e l s i n s t a l lations. Selectox

Process

On the other hand, there is a newly-developed process we consider e s p e c i a l l y s u i t e d t o handling a c i d gas c o n t a i n i n g up to 99 percent C O 2 but f r e e of o l e f i n s ; t h i s is the Selectox process, which was described t o the October, 1980 j o i n t meeting of the American and Mexican I n s t i t u t e s of Chemical Engineers. This is d e r i v e d from the BSR/Selectox process which has now been working f o r three years converting 1 t o 2 percent H 2 S in a Claus t a i l gas process. F i g u r e 2 is a photograph of the p l a n t of W i n t e r s h a l l , A.G. a t Lingen, West Germany, described p r e v i o u s l y ( 2 ) . Selectox c a t a l y s t was developed t o o x i d i z e H 2 S t o sulfur and S 0 2 in the presence of hydrogen, p a r a f f i n hydrocarbons o r ammonia. The l a t t e r compounds are e f f e c t i v e l y i n e r t at temperatures which a l l o w complete o x i d a t i o n of H 2 S . F i g u r e 3 shows the d i r e c t o x i d a t i o n s e c t i o n of the Lingen p l a n t . About 80 percent recovery of sulfur is achieved, even though the i n i t i a l c o n c e n t r a t i o n of H 2 S is only 1 to 2 percent. The same c a t a l y s t can be a p p l i e d t o higher concentrations of H 2 S . A l l the heat o f r e a c t i o n of H 2 S to form sulfur o r S O 2 is r e l e a s e d in the Selectox r e a c t o r ; in the c o n f i g u r a t i o n of Figure 3 the o u t l e t temperature approaches the maximum we t h i n k d e s i r a b l e w i t h a 5 percent c o n c e n t r a t i o n of H 2 S in the feed gas. With more than 5 percent H 2 S , the c o n f i g u r a t i o n o f F i g u r e 4 is used to p r o v i d e temperature c o n t r o l . Spent gas is r e c y c l e d through the S e l e c t o x r e a c t o r t o keep i t s temperature in a d e s i r able range. One o r more s i n g l e - p a s s Claus r e a c t o r s may f o l l o w the Selectox r e a c t o r , u s i n g Selectox o r alumina c a t a l y s t . I t is convenient that the normal temperature l e a v i n g the r e c y c l e blower c o i n c i d e s w i t h the d e s i r e d Selectox r e a c t o r i n l e t temperature. Thus the r e c y c l e acts as a thermal f l y w h e e l , keeping the S e l e c t o x r e a c t o r in c o n d i t i o n t o convert H 2 S even though i t s f r e s h feed may be t e m p o r a r i l y slowed or made too l e a n . We expect the process to be very s t a b l e . Union and Parsons are conf i d e n t o f the new process, based on experience at Lingen and ext e n s i v e p i l o t u n i t work, and we expect that design of the f i r s t commercial p l a n t w i l l be underway by the time t h i s paper is presented. The Selectox c a t a l y s t s u f f e r s a c t i v i t y l o s s when n o n - p a r a f f i n




BEAVON ET AL.

ο CO

1 6 .δ



64

AIRSELECTOX REACTOR


ANALYZER N2, C02 WITH 1 TO 2% H2S ca. 2% H2

Or

1 H20 SULFUR ca. 80% YIELD Figure 3.

Direct oxidation section of BSR/ Selectox plant.



»

Figure 4. Two-stage Selectox process with recycle.

APPROXIMATE SULFUR YIELD

*HTM = HEAT TRANSFER MEDIUM

ACID GAS FEED 1 TO 40% H2S

AIR->

HTM*

»> TAIL GAS TO TREATING OR INCINERATOR


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hydrocarbons are i n c l u d e d in the feed; removing the contaminants allows a c t i v i t y t o r e t u r n to normal, a t l e a s t in some cases. I n c l u s i o n of o l e f i n s in the feed is not recommended, hence the process probably does not f i t downstream of a p y r o l y z i n g type coal g a s i f i e r . The o v e r a l l sulfur recovery a c h i e v a b l e by the r e c y c l e S e l e c tox process i n c r e a s e s w i t h higher H 2 S c o n c e n t r a t i o n and w i t h the number o f c a t a l y s t i c stages used. Vfe may expect 94 t o 95 percent recovery from 1 0 percent H 2 S feed w i t h three c a t a l y s t i c stages; 96 t o 97 percent recovery should be had from 2 0 percent H 2 S f e e d . Carbony1 S u l f i d e COS u s u a l l y c o n s t i t u t e s about 5 percent of t o t a l sulfur in the g a s i f i e d c o a l . Passing over the complex problem o f e x t r a c t i n g COS from the gas, i t s conversion t o sulfur in the Claus u n i t r e q u i r e s some a t t e n t i o n . I t is best hydrolyzed t o H 2 S , then conv e r t e d t o sulfur. Alumina Claus c a t a l y s t is e f f e c t i v e f o r hydroly s i s a t above 650°F, and promoted c a t a l y s t s are s a i d t o be e f f e c t i v e a t s t i l l lower temperatures. Gases S t r i p p e d From Process Water Ammonia evolved in c o a l g a s i f i c a t i o n u s u a l l y is washed out w i t h water, t a k i n g w i t h it H 2 S , C O 2 , and HCN. Phenols and b a s i c n i t r o g e n compounds are a l s o present i f a p y r o l y z i n g g a s i f i e r is used. Such water u s u a l l y is p u r i f i e d by steam s t r i p p i n g , which l i b e r a t e s a vapor mixture of N H 3 , H 2 S , C 0 w i t h some HCN. Usable ammonia may be separated by f r a c t i o n a l d i s t i l l a t i o n (the WWT process) or by d i f f e r e n t i a l a b s o r p t i o n (the Phosam p r o c e s s ) ; in these cases a r i c h H 2 S is prepared f o r Claus p r o c e s s i n g . In most s i m i l a r a c t i v i t i e s in petroleum r e f i n e r i e s , the v a pors from s t r i p p i n g "sour water" are processed in a Claus p l a n t . With care in design and o p e r a t i o n of the s t r i p p e r , the vapors t y p i c a l l y c o n s i s t o f equal volumes of H 2 S , N H 3 and H 0 . Such a mixture can support high-temperature reducing flame in which N H 3 is destroyed. V i r t u a l l y complete d e s t r u c t i o n of N H 3 is r e q u i r e d ; otherwise ammonium s u l f a t e forms in downstream equipment, b l o c k i n g condenser tubes and sulfur p i p i n g . I f the N H 3 is o x i d i z e d t o form app r e c i a b l e amounts of n i t r o g e n oxides, S O 3 a l s o forms and c o n t r i b utes to b l o c k i n g as w e l l as causing d e a c t i v a t i o n of Claus c a t a l y s t by s u l f a t i o n . Therefore, the ammonia d e s t r u c t i o n step is best c a r r i e d out w i t h i n a narrow range o f c o n d i t i o n s (3). Any cyanide in the vapors is a l s o destroyed under the c o n d i t i o n s r e c ommended . Hot gases from the ammonia d e s t r u c t i o n step c o n t a i n n i t r o g e n , a t r a c e o f r e s i d u a l N H 3 , a s w e l l as H , H S, S O 2 and sulfur vapor. With proper design these gases can be fed i n t o a Claus type p r o c ess to make sulfur. I f the l a t t e r process uses Selectox c a t a l y s t ; 2

2

2

2


4.

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any SO3 formed by excess a i r in the NH3 d e s t r u c t i o n step w i l l do minimal harm, as S e l e c t o x c a t a l y s t is immune to s u l f a t i o n . Vapors from s t r i p p i n g process condensate may c o n t a i n phenols and oil matter. With proper d e s i g n these compounds can be o x i d i z e d completely to C 0 and CO. Incomplete o x i d a t i o n leads t o formation of t a r s which can b l o c k Claus c a t a l y s t beds. 2


Claus T a i l Gas P r o c e s s i n g Since the S e l e c t o x process is capable of w e l l over 90 percent sulfur recovery, the authors recommend a c a r e f u l c o s t - b e n e f i t study to see i f Claus t a i l gas processing should be r e q u i r e d w i t h such p l a n t s . I t might w e l l be found t h a t — s a y — 9 5 percent capture of sulfur in the c o a l conversion p l a n t is acceptable. If sulfur capture must be g r e a t e r than 95 percent, then treatment of Claus or Selectox t a i l gas w i l l be r e q u i r e d . To meet r e f i n e r y - s t y l e r e c o v e r i e s , there are few choices a v a i l a b l e . The t a i l gas must be hydrogenated, w i t h r e s u l t i n g H S recovered in one of s e v e r a l ways. The Beavon S u l f u r Removal Process (4) achieves almost t o t a l sulfur recovery, u s i n g the Stretf o r d process; it is e n e r g y - e f f i c i e n t because i n c i n e r a t i o n of the t a i l gas is not needed. The BSR/MDEA process, which uses methyldiethanolamine to e x t r a c t H S from hydrogenated t a i l gas, becomes more expensive w i t h low-strength a c i d gas, and i n c i n e r a t i o n of l a r g e q u a n t i t i e s of e f f l u e n t C 0 becomes c o s t l y . The BSR/Selectox t a i l gas process is a p o s s i b i l i t y i f l e s s s t r i n g e n t r e q u i r e ments are s e t . 2

2

2

Conclusion P l a n t s to produce l o w - s u l f u r f u e l s from c o a l , oil s h a l e , t a r sands or heavy oil f r e q u e n t l y are conceived t o use the Claus process to produce byproduct sulfur. Using c o a l g a s i f i c a t i o n as an example, it is seen that the c o n v e n t i o n a l Claus processisnot w e l l s u i t e d to the u s u a l problem of processing H S at a concent r a t i o n of 20% o r lower. A new process, r e c y c l e S e l e c t o x , is very s u i t a b l e to process H S in c o n c e n t r a t i o n s up to 40%, p r o v i d ed the a c i d gas is f r e e of o l e f i n s ; up to 95% recovery is p o s s i b l e , even w i t h very d i l u t e feed. Ammonia, H S, HCN, phenols and o i l y matter commonly are s t r i p p e d from process water and then are processed in by p a r t i a l o x i d a t i o n under c a r e f u l l y chosen c o n d i t i o n s to produce a gas s u i t a b l e f o r f u r t h e r Claus p r o c e s s i n g . Environmental r e g u l a t i o n s may f o r c e the "Claus" sulfur r e covery to exceed 99%, r e q u i r i n g t a i l gas treatment. High C 0 in the o r i g i n a l Claus feed, hence in the Claus t a i l gas, works s t r o n g l y a g a i n s t the t a i l gas processes which use amine s o l u t i o n to e x t r a c t H S, and subsequently r e q u i r e i n c i n e r a t i o n of r e s i d u a l H S in a l a r g e volume of C 0 . 2

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SULFUR: NEW SOURCES AND USES

Literature Cited 1. 2.


3. 4.

Goar, B. Gene, " S e l e c t i v e Gas T r e a t i n g Produces Better Claus Feeds"; Oil and Gas Journal May 5, 1980, 78. Beavon, D. K.; Hass, R. H.; Make, Β., "High Recovery, Low Emissions Promised f o r Claus-Plant Tail Gas"; Oil and Gas J o u r n a l March 12, 1979, 77 (11). U. S. Patent 3,970,743. Beavon, D. K.; F l e c k , R. Ν., "Beavon S u l f u r Removal Process f o r Claus P l a n t Tail Gas"; S u l f u r Removal and Recovery from I n d u s t r i a l Processes 1975, Advances in Chemistry 239.

RECEIVED October 5,

1981.


Sulfur: New Sources and Uses - American Chemical Society

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