ASPEN simulation of the SNG production process in an indirect coal-liquefaction plant
The synthetic natural gas (SNG) production process (methanation, CO-shift, and hydrogen removal) in an indirect coal-liquefaction plant was simulated using the Advanced System for Process Engineering (ASPEN). The simulation of the methanation unit agreed to within 12% of Fluor's design for converting carbon monoxide and carbon dioxide. A parametric study examined the effect of four important operating parameters on product composition, process thermal efficiency, and outlet temperature from the second methanation reactor. The molar split of gas feed to the CO-shift unit before methanation was varied from 0.2 to 0.6; variations of molar recycle ratio (0.01 - 0.67), molar steam-to-feed ratio (0.04 - 0.19), and feed temperature (478 - 533 K, 400-500/sup 0/F) to the first methanation reactor were also studied. A 50%-lower split improved thermal efficiency by 6%, but the mole % hydrogen and carbon monoxide in the product SNG required to meet pipeline-quality standards and temperature constraints were not met. Increasing the steam-to-feed ratio from 0.04 to 0.19 improved product quality but decreased thermal efficiency by 8%. By decreasing the feed temperature from 533 to 477 K (500 to 400/sup 0/F), product specifications and temperature constraints were met with no effect on thermal efficiency. However, it may be impractical to operate the reactor at 477 K (400/sup 0/F) because the kinetics are too slow. Increasing the recycle ratio from 0.4 to 0.67 had no effect on thermal efficiency, and temperature constraints and product specifications were met. The SNG production process should be optimized at recycle ratios above 0.67.
- Research Organization:
- Massachusetts Inst. of Tech., Oak Ridge, TN (USA). School of Chemical Engineering Practice
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5010680
- Report Number(s):
- ORNL/MIT-352; ON: DE82021107
- Resource Relation:
- Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL GASIFICATION
COMPUTER CALCULATIONS
COAL GASIFICATION PLANTS
COMPUTER-AIDED DESIGN
METHANATION
OPTIMIZATION
SIMULATION
COAL LIQUEFACTION
DEPOSITION
FLOWSHEETS
HYDROGEN
LURGI PROCESS
MATHEMATICAL MODELS
REMOVAL
SHIFT PROCESSES
SYNTHESIS GAS
THERMAL EFFICIENCY
CHEMICAL REACTIONS
DIAGRAMS
EFFICIENCY
ELEMENTS
FLUIDS
GASES
GASIFICATION
INDUSTRIAL PLANTS
LIQUEFACTION
NONMETALS
THERMOCHEMICAL PROCESSES
010405* - Coal
Lignite
& Peat- Hydrogenation & Liquefaction