6 The Η-Coal Process C. D. HOERTZ and J. C. SWAN
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Ashland Synthetic Fuels, Inc., P.O. Box 391, Ashland, KY 41101
The Η-Coal process is a development of Hydrocarbon Research Inc. (HRI). It converts coal by catalytic hydrogenation to sub stitutes for petroleum ranging from a low sulfur fuel o i l to an all distillate synthetic crude, the latter representing a poten tial source of raw material for the petrochemical industry. The process is a related application to HRI's Η-Oil process which is used commercially for the desulfurization of residual oils from crude o i l refining. The Η-Coal process has been thoroughly tested on bench scale and process development units. This work was initiated over 14 years ago and has continued until now through funding arrangements with government and industry. As a result, there is a data base of more than 60,000 hours at the bench scale level and 10,000 hours on a 3 TPD Process Development Unit. There is now a large scale pilot plant under construction that is designed to process 200 to 600 TPD of coal. This will be the last step necessary to establish technical and economic feasibility for Η-Coal and provide design data for a commercial plant. The Η-Coal process is primarily a liquefaction system but does produce s i g n i f i c a n t q u a n t i t i e s o f SNG and LPG. Figure 1 presents a schematic o f the process. B r i e f l y , c o a l i s cleaned, d r i e d , p u l v e r i z e d and s l u r r i e d w i t h process-derived o i l i n the p r e p a r a t i o n s e c t i o n . I t i s then pumped t o r e a c t o r pressure, mixed w i t h hydrogen, heated, and charged t o the r e a c t o r . There, the c o a l , r e c y c l e o i l and hydrogen r e a c t i n the presence of a c a t a l y s t a t pressures up t o 3500 p s i g and temperatures t o 850 F. Depending on the s e v e r i t y s e l e c t e d , the product s l a t e can be an a l l d i s t i l l a t e m a t e r i a l o r a l i q u e f i e d residuum w i t h only a s m a l l amount of d i s t i l l a t e . A f t e r l e a v i n g the r e a c t o r , the l i q u i d e f f l u e n t i s t r e a t e d t o provide a l o w - s o l i d s r e c y c l e o i l which i s used t o s l u r r y the c o a l . The balance of the l i q u i d i s f r a c t i o n a ted i n t o d i s t i l l a t e products and ash-containing residuum. The heavy ends can be f u r t h e r t r e a t e d t o recover a d d i t i o n a l ash-free 0-8412-0516-7/79/47-110-091$05.00/0 © 1979 American Chemical Society
In Coal Conversion Technology; Pelofsky, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
In Coal Conversion Technology; Pelofsky, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1979. ^
Figure 1.
-Up Make-Up Hydrogen
Recycle Slurry Oil
Feed Heater
Reactor
Hydrogen
Recycle
O xidatioi Oxidation
Solids Reduction
Η-Coal process schematic
ι
Steam ~
Ash
Τ
ι *
Oxygen
Separator
Product Gases
Fractionator
Dis tillable Liquid Products
Gas Cleanup
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6.
HOERTZ AND SWAN
The
Η-Coal Process
93
hydrocarbons or used as feed to a hydrogen p l a n t . F i g u r e 2 i n d i cates the range the product s l a t e can a t t a i n , depending upon commercial requirements.
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The r e a c t o r i s the key to the v e r s a t i l i t y of the H-Coal process. F i g u r e 3 i s a s i m p l i f i e d diagram of the r e a c t o r . The concept i n v o l v e s a c a t a l y s t bed that i s kept i n an expanded or e b u l l a t e d s t a t e by charging the feed and a d d i t i o n a l r e c y c l e o i l to the bottom of the r e a c t o r . The products, i n c l u d i n g unreacted c o a l and ash, flow through the c a t a l y s t and a r e removed from the r e a c t o r a t a p o i n t above the top of the c a t a l y s t bed. An e x t e r n a l separator removes gaseous products and r e c y c l e hydrogen from the liquid. Because the c a t a l y s t bed i s c o n s t a n t l y i n motion, a p o r t i o n of the c a t a l y s t can be r o u t i n e l y withdrawn and replaced w i t h f r e s h c a t a l y s t . I n p r a c t i c e , perhaps one percent of the r e a c t o r inven t o r y would be replaced d a i l y thus m a i n t a i n i n g a high l e v e l of a c t i v i t y . I n a d d i t i o n , t h i s type of r e a c t o r w i l l permit a high degree of i s o t h e r m a l o p e r a t i o n and achieve a h i g h l e v e l of e f f i c i e n c y through d i r e c t u t i l i z a t i o n of the energy generated by the r e a c t i o n . At the present time, a consortium of i n d u s t r y and government i s funding an Η-Coal p i l o t p l a n t being constructed a t C a t l e t t s b u r g , Kentucky. Table I provides a summary of the pro j e c t . The p l a n t has been designed to process from 200 t o 600 TPD of both bituminous and subbituminous c o a l , producing a nominal 600 t o 1800 BPD of product. The cost i s p r e s e n t l y estimated to be $275 m i l l i o n i n c l u d i n g $35 m i l l i o n f o r research and engineering, $115 m i l l i o n f o r p l a n t c o n s t r u c t i o n and $125 m i l l i o n f o r 2 years o p e r a t i o n and subsequent d i s m a n t l i n g . The funding group i n c l u d e s the Department of Energy, the State of Kentucky, the E l e c t r i c Power Research I n s t i t u t e , Standard O i l of Indiana, M o b i l , Conoco Coal Development and Ashland. C o n s t r u c t i o n i s approximately 70 percent complete w i t h mechanical completion scheduled l a t e r t h i s year. The o b j e c t i v e s of the p i l o t p l a n t program a r e summarized i n Table I I . The p l a n t i s s i z e d l a r g e enough to demonstrate mechani c a l o p e r a b i l i t y of prototype and commercial equipment i n the en vironment of c o a l conversion process c o n d i t i o n s . At the same time, s u b s t a n t i a l q u a n t i t i e s of products r e p r e s e n t a t i v e of commercial operations w i l l be a v a i l a b l e f o r e v a l u a t i o n and development of downstream processing and markets. The f u l l y i n t e g r a t e d p i l o t p l a n t w i l l v e r i f y y i e l d s t r u c t u r e and supply design and other engineering data r e q u i r e d f o r the design of a commercial p l a n t . F i n a l l y , a c t u a l o p e r a t i o n of the equipment over extended periods w i l l a l l o w extensive e v a l u a t i o n of m a t e r i a l s of c o n s t r u c t i o n and development of maintenance requirements.
In Coal Conversion Technology; Pelofsky, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
COAL CONVERSION
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94
Severity
Figure 2.
TECHNOLOGY
Probable Range of P i o n e e r Plant Operation
Yield vs. severity
In Coal Conversion Technology; Pelofsky, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
HOERTZ
AND SWAN
The
Η-Coal Process
Downloaded by MONASH UNIV on November 22, 2015 | http://pubs.acs.org Publication Date: November 21, 1979 | doi: 10.1021/bk-1979-0110.ch006
Product Vapor
Catalyst
HX3
Addition
Catalyst
