Logic, Technology and Effect on Coal Liquefaction Conditions on Final Upgraded Prouct Slate
Publication Date: 2012-Jul-17
The IP.com Prior Art Database
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LOGIC, TECHNOLOGY AND EFFECT OF COAL LIQUEFACTION CONDITIONS ON FINAL
UP-GRADED PRODUCT SLATE
M. R. Smith, D. A. Hubbard and C. C. Yang Kellogg-Rust Synfuels, Inc. Houston, Texas 77046
United States of America
Conditions chosen for the coal liquefaction reactor and for the de- ashi~g step determine the nature of the syncrude intermediate product. In the succeeding upgrading steps, this syncrude must be converted to salable products. A logical sequence is proposed to establish the overall process configuration, where hydrocracking, hydrotreatment and other refining steps are integrated with the initial conversion units and the hydrogen generation system.
Reactor parameters affecting coal conversion will be discussed with emphasis on the SRC-I process. Relation of hydrogen consumption to product dis- tribution and product H/C ratio, sulfur, oxygen, and nitrogen content will be developed. Merits of two-stage vs. single-stage coal conversion and v~ious ash removal methods wil~l also be discussed.
A review of published data on upgrading of raw coal liquid ~ made. Production of salable gasoline, jet fuel, diesel oil, and fuel oils from coal liquids will be compared to similar data starting with shale oil, petroleum, and tar sands.~esses employed are hydrocracking, hydrotreatment, catalytic reforming, and catalytic cracking. Delayed or Fluid Coking plus hydrotreating are also proposed for processing shale oils and tar sands.
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Direct coal liquefaction has rapidly approached the status of a commercial reality during the past few years. New processes, such as H-Coal, SRC, and Exxon Donor Solvent, offer advan(ages over indirect liquefaction routes where liquids were formed from synthesis gas generated by coal gasification.
These advantages, primarily in improved carbon utilization, are gained by emp- ployment of a more-complex processing .scheme which in turn tends to increase:
the cost of a practically-sized facility. Preparation of designs for commercial- scale plants using direct coal liquefaction certainly involves a thorough under- standing of the strengths and limitations of the several technologies involved. Beyond familiarity with individual process steps, however, planning of the over- all design requires comparative studies of the options available and of the sequences in which they could be applied.
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LOGICAL DEVELOPMENT OF PROCESS SEQUENCE
Experience and intuition strongly indicate that no single overall process scheme can be assembled to fully ~erve the needs of any and all who might contemplate direct coal liquefaction. Depending upon the nature of the selected coal feedstock, product requirements and preferences for byproduct sale or utilization, several process configurations are possible. For the dis- cussion which follows, the product slate will be assumed to be restricted to transportation fuels, i.e., diesel and gasoline.
A complex processing scheme is necessary to ap...