EP0273616A2 - Reinigung von Abwässern - Google Patents

Reinigung von Abwässern Download PDF

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Publication number
EP0273616A2
EP0273616A2 EP87310853A EP87310853A EP0273616A2 EP 0273616 A2 EP0273616 A2 EP 0273616A2 EP 87310853 A EP87310853 A EP 87310853A EP 87310853 A EP87310853 A EP 87310853A EP 0273616 A2 EP0273616 A2 EP 0273616A2
Authority
EP
European Patent Office
Prior art keywords
steam
flash evaporation
liquor
gasification
aqueous
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP87310853A
Other languages
English (en)
French (fr)
Other versions
EP0273616A3 (de
Inventor
Francis John Peter Doherty
Keith Raymond Tart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
British Gas PLC
Original Assignee
British Gas PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB8630047A external-priority patent/GB8630047D0/en
Application filed by British Gas PLC filed Critical British Gas PLC
Publication of EP0273616A2 publication Critical patent/EP0273616A2/de
Publication of EP0273616A3 publication Critical patent/EP0273616A3/de
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/72—Other features
    • C10J3/82—Gas withdrawal means
    • C10J3/84—Gas withdrawal means with means for removing dust or tar from the gas
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/02—Fixed-bed gasification of lump fuel
    • C10J3/20—Apparatus; Plants
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0913—Carbonaceous raw material
    • C10J2300/093—Coal
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0956—Air or oxygen enriched air
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0959—Oxygen
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0973—Water
    • C10J2300/0976—Water as steam
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/18—Details of the gasification process, e.g. loops, autothermal operation
    • C10J2300/1807—Recycle loops, e.g. gas, solids, heating medium, water

Definitions

  • This invention relates to the purification of aqueous effluents and especially to the recovery of aqueous components used in gasification processes, such that they may be reused. More particularly, the invention relates to the recovery and reuse of such components in association with the production of environmentally acceptable by-products.
  • the product gas may be treated to remove excess steam and inorganic and organic contaminants. This removal process is usually effected by quenching and cooling the synthesis gas thereby causing tars, oils and aqueous liquors to condense out. The condensate may then be further treated to separate the aqueous and non-aqueous components.
  • an oxygen-containing gas eg. air or oxygen per se
  • non-aqueous components comprising tars and oils, being carbonaceous in nature, can be returned to the gasifier as a feedstock.
  • aqueous component either in liquid or vapor form, to supplement the steam being supplied as a gasifying agent.
  • the present invention provides a process for the steam-oxygen gasification of carbonaceous materials to produce a synthesis gas which is treated to separate out condensible components including an aqueous liquor, which process comprises subjecting said aqueous liquor to flash evaporation at a pressure greater than that at which gasification is effected, to produce a vapor product containing mainly steam and a residual aqueous liquid product, thereafter recycling a portion of said liquid product to the flash evaporation stage, and subjecting a second portion of said liquid product to incineration.
  • the said vapor product is recycled for use in gasification. After mixing with oxygen and, possibly, additional steam, it is made to react with the carbonaceous feed material.
  • the aqueous liquor In the flash evaporation stage, the aqueous liquor, at elevated pressure eg. 40 bar, forms two fractions.
  • the first fraction a vapour fraction
  • the second fraction is a liquid residue containing water, dissolved inorganic compounds, such as chlorides, and the remaining organic species.
  • a further fraction of water, as steam, may be recovered from the liquid residue by recycling a portion of it back to the flash evaporator vessel where it is evaporated in the presence of further amounts of the aqueous liquor.
  • Another portion of side stream of the liquid residue may be incinerated to produce solid and gaseous final products.
  • a recycle pump to bring the pressure of the recycled residue back up to the elevated pressure required for the flash evaporation. It may be convenient to place the recycle pump upstream of the incinerator side stream so that residue is pumped to the incinerator under pressure for flash evaporation within the incinerator.
  • liquors derived from the gasification of coal as the carbonaceous material, it may be preferred to pretreat the aqueous liquor prior to flash evaporation.
  • the liquor may be subjected to steam stripping to remove volatile compounds such as hydrogen sulphide and ammonia, which can be separately processed to give environmentally acceptable products.
  • the present invention offers the advantage that only a small part of the condensed water from the gasification stage leaves the process. The remainder is recycled in such a way as to reduce the energy and water demands of the process. Thus the quantity of steam or water, which must be rendered fit for discharge to the enviornment, is greatly reduced.
  • the present invention has two advantages over processes in which the recycle of water to the gasifier is made in the liquid phase. Firstly liquid phase recycles result in greatly increased concentrations of involatile solutes, of which the most troublesome is chloride. This is avoided by the vapour phase recycle of the present invention. Secondly, the recycling e of liquids may adversely affect gasifier operation in the main process of coal gasification.
  • a further advantage of the invention is that it renders more economic the use of an incineration process for the aqueous liquor waste.
  • Incineration processes for aqueous wastes require costly support fuel.
  • the present invention drastically reduces the fuel demand and in certain cases the organic content of the waste for incineration should be sufficient to allow combustion without support fuel. This saving is achieved at a small extra cost, which results from the downgrading of a high pressure steam supply to the pressure and temperature of the vapour recycled to the gasifier.
  • the combination of the invention with an incinerator also has the advantage of reducing to zero the liquid effluent discharged by the process to the environment.
  • the effluent purification process can be applied to the gasification of coal.
  • Coal 11, steam 12 and oxygen 13 are reacted in a gasifier 1, for example, an ash-slagging gasifer, as described in "The Chemistry of Coal Utilization” (2nd Supplementary Volume), 1981, John Wiley & Son Inc.
  • the steam supply is supplemented by steam 46 obtained from the flash evaporation device 40.
  • Heat for the flash evaporation is provided, for example, by steam supply 49.
  • Hot product gas 14 is subjected to quenching (in quench 2) and cooling (in gas coolers 3) to produce a gaseous product 21 and a liquid condensate 22.
  • the gaseous product 21 is suitable for use as a synthesis gas, fuel gas or for upgrading to substitute natural gas.
  • the liquid condensate 22 is passed to a process unit, 5, for separation of the non-aqueous portion, 23, which consists of tarry and oily materials.
  • the non-aqueous portion 23 may be recycled to the gasifiers, incinerated or sold. While part of the aqueous condensate may be recycled as stream 24 to the quench, there must remain an aqueous condensate stream 41, requiring treatment as a waste.
  • This aqueous liquor 41 which may optionally be first subjected to steam stripping, is fed to the flash evaporator vessel (operating at for example 40 bar) 40 via pump 41. Within pump 42 the liquor pressure is raised to, for example, about 100 bar. The liquor is flash evaporated to give a vapor portion 46 which is used as a gasifying agent, and a residual liquor 47. The residual liquor stream 47 is divided into a recycle stream 44 and an incinerator side stream 45. As shown in the drawing all of the residual liquor, even that not required for recycle, passes through the recycle pump 43. Prior to re-injection into the flash evaporator, the recycle liquor 44 must be reheated in heater 48.
  • the aqueous liquor 41 may be subjected to steam stripping to remove volatile sulphur compounds prior to flash evaporation.
  • the off-gases comprising hydrogen sulphide and ammonia may be further treated in, for example, a Claus Plant to recover elemental sulphur.
  • a Claus Plant to recover elemental sulphur.
  • a portion 45 of the residual liquor 47 is the only waste remaining for disposal. Thus when the liquor 44 in the recirculation loop contains dissolved solids of a predetermined concentration, a portion 45 is drawn off for disposal, by incineration or otherwise. This waste stream 45 is very small in comparison with the original waste stream 41.
  • a typical application of the invention is in combination with an ash-slagging gasifier operated at a pressure of 32 bar.
  • the flash evaporation of the liquor should yield vapour at a pressure of 38 bar.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Industrial Gases (AREA)
  • Heat Treatment Of Water, Waste Water Or Sewage (AREA)
EP87310853A 1986-12-16 1987-12-10 Reinigung von Abwässern Withdrawn EP0273616A3 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8630047A GB8630047D0 (en) 1986-12-16 1986-12-16 Purification of effluent liquors
GB8630047 1986-12-16
GB8704804 1987-03-02
GB8704804A GB2198744A (en) 1986-12-16 1987-03-02 Gasification process

Publications (2)

Publication Number Publication Date
EP0273616A2 true EP0273616A2 (de) 1988-07-06
EP0273616A3 EP0273616A3 (de) 1989-03-29

Family

ID=26291703

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87310853A Withdrawn EP0273616A3 (de) 1986-12-16 1987-12-10 Reinigung von Abwässern

Country Status (1)

Country Link
EP (1) EP0273616A3 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103159343A (zh) * 2012-11-09 2013-06-19 唐山科为工控技术有限公司 煤气冷凝水处理方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3036057A (en) * 1959-08-12 1962-05-22 Phillips Petroleum Co Flash concentration of solutions containing polyolefins
US3234109A (en) * 1964-07-28 1966-02-08 Gen Electric Method and apparatus for flash distillation
DE2861727D1 (en) * 1978-04-28 1982-05-19 Texaco Development Corp Process for producing synthesis gas with wash water purification and novel flash column for use in said process
US4175929A (en) * 1978-08-29 1979-11-27 The United States Of America As Represented By The United States Department Of Energy Process for control of pollutants generated during coal gasification
DE2853989C2 (de) * 1978-12-14 1980-07-31 Metallgesellschaft Ag, 6000 Frankfurt Verfahren zum Behandeln von wasserhaltigem Kondensat aus der Kühlung des Rohgases der Druckvergasung
DE3207779A1 (de) * 1982-03-04 1983-09-08 Metallgesellschaft Ag, 6000 Frankfurt Verfahren zum behandeln von wasserhaltigem kondensat aus der kuehlung des rohgases der kohledruckvergasung
GB8305873D0 (en) * 1983-03-03 1983-04-07 Oil Reclamation Int Heat treatment of liquids

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103159343A (zh) * 2012-11-09 2013-06-19 唐山科为工控技术有限公司 煤气冷凝水处理方法

Also Published As

Publication number Publication date
EP0273616A3 (de) 1989-03-29

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Inventor name: TART, KEITH RAYMOND

Inventor name: DOHERTY, FRANCIS JOHN PETER