Steam stripping recycle developed for gasifier liquors
When coal is gasified in fixed bed processes such as the British Gas/Lurgi Slagging Gasifier, the crude product contains steam which on cooling results in the formation of an aqueous liquor. This liquor contains soluble species such as hydrogen sulfide, ammonia, hydrogen cyanide, hydrogen chloride and phenols. These liquors are environmentally unacceptable and their disposal can be a serious problem. British Gas has developed a new process for the purification of such aqueous effluent liquors. It has been discovered that the gasification steam may be used, at gasification pressure, to strip the volatile compounds from such liquors and thereby include these compounds in the reactant stream where they are gasified within the main reactor. A portion of the gasifier feed steam may be superheated, passed through the condensate liquor, combined with the remaining portion of the gasifier feed steam and then injected through the tuyeres of the gasification plant. In this way an effluent liquor is produced with contains substantially only inorganic compounds, and these can be removed by conventional treatments. Although high-pressure steam stripping removes any lighter volatile components, compounds such as the higher molecular weight phenols may not be readily stripped out. The invention therefore provides also for the use of oxygen-containing gas under pressure to purify the effluent. The oxygen-containing gas may either be used alone, in a mixture with steam or as a second stage following the steam-stripping process.
- OSTI ID:
- 6683049
- Journal Information:
- Pace Synth. Fuels Rep.; (United States), Journal Name: Pace Synth. Fuels Rep.; (United States) Vol. 24:1; ISSN PSFRD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010404* -- Coal
Lignite
& Peat-- Gasification
010800 -- Coal
Lignite
& Peat-- Waste Management
AMMONIA
AROMATICS
BGC-LURGI SLAGGING PROCESS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL GAS
COAL GASIFICATION
CYANIDES
DEPHENOLIZATION
ELEMENTS
FLUIDS
GASES
GASIFICATION
HOT GAS CLEANUP
HYDRIDES
HYDROCHLORIC ACID
HYDROCYANIC ACID
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
HYDROXY COMPOUNDS
INORGANIC ACIDS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
OXYGEN
PHENOLS
PURIFICATION
RECYCLING
REMOVAL
SEPARATION PROCESSES
STEAM
SULFIDES
SULFUR COMPOUNDS
TECHNOLOGY ASSESSMENT
THERMOCHEMICAL PROCESSES