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
  • C10J3/02—Fixed-bed gasification of lump fuel
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
• • 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
  • C10J3/06—Continuous processes
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
  • C10K1/00—Purifying combustible gases containing carbon monoxide
  • C10K1/04—Purifying combustible gases containing carbon monoxide by cooling to condense non-gaseous materials
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F2001/007—Processes including a sedimentation step
• • 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
  • C10J2300/0916—Biomass
• • 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
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/1687—Integration of gasification processes with another plant or parts within the plant with steam generation
• • 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
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/169—Integration of gasification processes with another plant or parts within the plant with water treatments
• • 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 a process and an apparatus for the gasification of carbonaceous solids, wherein in a first process step solids are at least partly converted to CO and H 2 in a gasification, wherein in a second process step a stream containing water is separated, and wherein in a third process step the water-containing stream obtained in the second process step is subjected to a water purification.
• Gasification is referred to as a chemico-physical process, in which at least part of a solid matter is transferred into a gaseous end product.
• the gaseous end product is a mixture which chiefly consists of carbon monoxide (CO) and hydro- gen (H 2 ).
• CO carbon monoxide
• H 2 hydro- gen
• the actual gasification is effected by exothermal combustion of the solids.
• the products of this reaction can react further with the solids and additionally introduced steam or among each other. Except for the combustion reaction, all essential reactions are equilibrium reactions, so that the conversion also can proceed in the reverse direction.
• the composition of the product gases generally is very close to the equilibrium.
• the synthesis gas CO and H 2 obtained therein must be purified subsequently. Since during the reac- tion steam is required as educt and water is one of the possible reaction products, the water amongst others must be removed from the gas stream.
• Such process is known for example from DE 41 07 109 C1 .
• Solid fuels are gasified at a pressure in the range from 10 to 100 bar with gasification media containing oxygen and steam for generating a raw gas.
• the raw gas coming from the gasification is cooled to temperatures of 20 to 200 °C, whereby a condensate rich in water is obtained.
• the condensate is separated and at least partly evaporated, wherein condensate vapor and a salt-containing brine are withdrawn separately.
• the salt-containing brine is burnt, the condensate vapor is partly added to the purified raw gas.
• DE 35 15 484 describes that the condensate obtained in the stepwise cooling of the product gas is cooled in a washer-cooler, which is charged with circulating water, whereby halogens are largely washed out.
• the used washing water which has temperatures of 120 to 220 °C, is expanded to a lower pressure, whereby flash steam and a liquid phase are obtained.
• the flash steam virtually free of halogens is discharged, the major part of the liquid phase is again passed into the washer-cooler, and the residual liquid phase is supplied to a disposal.
• DE 32 07 779 A1 describes that the condensate obtained from the synthesis gas is expanded and supplied to a separating means, from which a condensate phase largely consisting of water is withdrawn.
• the condensate phase is cooled in direct contact with colder gas, before it is used for cooling the raw gas stream.
• the heated, steam-containing cooling gas is supplied to a combustion and utilized e.g. for heating the reactor.
• DD 147679 describes the recirculation of a stream substantially consisting of water, which originates from a hydroclone in which a stream rich in solids is separated from a stream poor in solids.
• the overflow stream poor in solids is admixed to the educt stream of the gasifier and serves as source for the required steam in the reaction.
• the underflow stream rich in solids is distilled at atmospheric pressure for further purification.
• GB 2 198 744 A finally describes a coal gasification in the fixed bed, in which after separation of the gases the waste water stream is guided into an evaporation means. From there, the gaseous constituent is recirculated into the reactor as gasification medium.
• this object is solved by a process with the features of claim 1 .
• a carbonaceous solid matter is gasified and at least partly converted to carbon monoxide and hydrogen in the presence of oxygen and steam.
• the gas mixture produced then is supplied to a separating device, in which liquid fractions are separated from gaseous fractions, whereby a so-called raw gas stream and a stream containing water are obtained.
• the liquid stream containing water finally is subjected to water purification.
• the water purification is effected such that three streams with different degrees of purity are obtained.
• the first stream has the highest degree of purity, almost exclusively consists of water, and has the following composition:
• Such stream thus is suitable to be utilized for steam generation.
• the first stream can be used as cooling water inside the plant.
• the second stream has a medium degree of purity:
• Ammonium nitrogen (short NH -N) mg/l 5 - 500
• the third stream has the lowest degree of purity and carries high solids content: Table 3: Substances contained in the third stream
• the procedure according to the invention provides for the recirculation of each of these three streams. That stream of water which has the highest degree of purity is supplied to a water inlet of a steam generation; that stream of water which has the medium degree of purity is supplied to a further treatment of ash obtained in the gasification reactor; and/or that stream of water which has the lowest degree of purity and is rich in solids is guided back into the gasification reactor.
• the streams with the medium and the lowest degree of purity also can jointly be recirculated into the gasification zone, whereby a particularly high utilization of the contained organic components can be effected.
• the degree of purity of the first stream does not reach the purity necessary for steam generation. With the same pH value it then has a composition at which the individual components are present in three times, in part even six times the concentration as compared to the concentration indicated in Table 1 .
• a stream with this composition can be utilized as cooling water stream at any point of the process, without the cooling water being evaporated or can be added to cooling tower of the gasification plant.
• the stream with the lowest degree of purity is separated by decanting in a first step. It is possible to further lower the water content for example by evaporation.
• the remaining stream subsequently is supplied to a reverse osmosis.
• the reverse osmosis is a physical process for concentrating substances dissolved in liquids, in which the natural process of osmosis is reversed with pressure.
• the medium in which the concentration of a certain substance should be reduced is separated from a medium in which the concentration should be increased by a semipermeable membrane. In the present case, the concentration of solids in the entering stream of water should be lowered and be increased in the exiting stream with the lowest degree of purity.
• the resulting purified first stream preferably once again is subjected to a second reverse osmosis, in order to obtain the stream with the highest and the stream with the medium degree of purity.
• Parts of the stream with the medium degree of purity also can be obtained by an ion exchanger upstream of the reverse osmosis.
• the two partial streams with the medium degree of purity from ion exchanger and reverse osmosis subsequently are mixed.
• Denitrification is understood to be the conversion of the nitrogen bound in the nitrate (NO3 " ) to molecular nitrogen (N 2 ) by certain heterotrophic and some autotrophic bacteria which are bound to a membrane.
• oxidizable substances such as organic substances, hydrogen sulfide (H 2 S) and molecular hydrogen (H 2 ), are oxidized with nitrate as oxidant (oxidizing agent) in the absence of molecular oxygen (O 2 ) (anoxic conditions).
• Nitrification designates the bacterial oxidation of ammonia (NH 3 ) to nitrate (NO3). It consists of two coupled partial processes: In the first part ammonia is oxidized to nitrite, which in the second partial process is oxidized to nitrate.
• a removal of the organic compounds preferably is effected by the anaerobic treatment with bacteria in an oxygen-free environment. Furthermore, it was found to be advantageous to utilize the steam generated in the steam generation inside the steam supply system for the gasification process, e.g. for preheating educts, e.g in distillation processes and/or to use the steam for generating electric energy, e.g. for operating a turbine. Thus, the water demand of the process can be reduced.
• the stream of water with the medium degree of purity is used in accordance with a development of the invention.
• this ash is obtained by reaction of the carbonaceous solids such as coal or biomass and falls through a grate provided in the bottom region of the fixed bed .
• water is introduced and the ash thus is flushed out.
• stream of water which has the highest degree of purity and/or that stream of water which has the medium degree of purity may be necessary to subject that stream of water which has the highest degree of purity and/or that stream of water which has the medium degree of purity to a further purification before recirculation into the steam generation or the further ash treatment.
• Such further purification provides for largely recirculating the streams of waste water even when a high amount of soiling is introduced into the process by the solid starting material used.
• Possible processes for the further purification may be chemical processes such as the Fenton reaction (an oxidation of organic substrates with hydrogen peroxide in an acidic medium catalyzed by iron salts), ozonization (sterilization by introducing ozone), the use of activated carbon (as adsorbent) and/or the addi- tion of calcium hydroxide (for lowering the water hardness by ion exchange).
• the use of further precipitating or coagulating agents also is conceivable.
• separators and/or a sewage treatment plant can also be used.
• An advantageous aspect of the invention in addition provides that the solids are gasified in a fixed bed. ln a fixed-bed gasification it was found to be favorable to introduce that stream of water which has the lowest degree of purity above the fixed bed, wherein the stream is injected as finely distributed as possible.
• the invention furthermore comprises a plant for the gasification of a carbonaceous solid matter with the features of claim 9. Accordingly, the plant comprises a gasification reactor in which the solids are at least partly converted to carbon monoxide and hydrogen, a separating device in which the raw gas is separated from a liquid, aqueous stream, and a water purification device in which the aqueous liquid stream obtained in the separating device is purified.
• the water is separated into three streams with different degrees of purity.
• the stream of water which has the highest degree of purity is supplied to a water inlet of a steam generation; via a second conduit, that stream of water which has the medium degree of purity is supplied to a means for the further treatment of ash from the gasification reactor; and/or via a third conduit that stream of water which has the lowest degree of purity is guided back into the gasification reactor.
• the device for separating the gaseous fraction from the liquid stream is designed either as condenser or as droplet separator.
• the design as condenser has the advantage that at the same time the gas stream is cooled further.
• the gas stream can already be cooled previously and the thermal energy withdrawn in the cooling can be utilized at some other point.
• the plant according to the invention advantageously also includes a gas cooling between the gasification reactor and the separating device, which is recom- mendable in particular when the gas-liquid separator is formed as droplet separator and thus cooling must be effected at some other point in the process.
• the plant according to the invention preferably includes an ammonia recovery device between the separating device and the further ash treatment.
• the contained liquid stream from the gas cooling is separated further by decanting, wherein substantially tars, oils, phenols and ammonia (NH 3 ) are separated.
• a further purification of the water can be effected by a downstream Phenosol- van ® process.
• the Phenosolvan ® process the phenol-containing water is intimately mixed with Phenosolvan ® in a multistage extractor according to the mixer-separator principle. After subsequent phase separation, the largest part of the phenols is present in the solvent. This process is repeated several times, wherein the phenol-containing water and the solvent are guided in counterflow. The solvent is separated from the phenols by distillation and flows back into the extractor for again washing out the phenols.
• a CLL process Chemie Linz-Lurgi
• acid gases and ammonia are removed from the condensate of the Phenosolvan ® process by selective stripping.
• Fig. 1 shows a flow diagram of a conventional gasification process with waste water aftertreatment according to the prior art
• Fig. 2 schematically shows a flow diagram of a process according to the invention.
• solids are introduced into a gasification reactor 10 via conduit 1 and oxygen is introduced via conduit 2.
• oxygen is introduced via conduit 2.
• conduit 14 the gas mixture formed by the reaction is supplied from the reactor 10 to a gas cooling 20. From this gas cooling, the raw synthesis gas obtained is withdrawn via conduit 21 .
• conduit 22 the liquid stream obtained is supplied to a gas/liquid separation 23. From there, it is introduced into an ammonia recovery 25 via conduit 24. Between the gas/liquid separation 23 and the ammonia recovery 25, a Phenosolvan ® process can be provided (not shown in Fig. 1 )
• the liquid stream containing water is transferred into the water treatment 30 via conduit 26.
• aqueous waste water on the one hand is discharged via conduit 31 and possibly treated such that the waste waters can be disposed of.
• Via conduit 32 a stream is withdrawn, which contains a large part of the solid particles and therefore is also referred to as slag stream.
• the stream containing solids is supplied to a drier 33 in which the contained water is evaporated by supplying energy and escapes into the atmosphere.
• the dried slag then for example can be brought to a dis- posal site.
• the ash is discharged via conduit 1 1 and supplied to a further ash treatment 12.
• the ash stream is made flowable by means of so-called make-up water.
• the make-up water is fed from a source into the further ash treatment 12.
• the flowable ash then is withdrawn via conduit
• the water obtained from the waste water aftertreatment is disposed of as waste water, but not recirculated into the process. Instead, fresh water is fed in at some other point of the process.
• FIG. 2 shows the configuration of the process according to the invention in a flow diagram, wherein the solids to be gasified likewise are supplied to the gasification reactor 10 via conduit 1 and oxygen is supplied via conduit 2. From the gasification reactor 10 ash is withdrawn via conduit 1 1 and supplied to a further ash treatment 12. From this further ash treatment, the ash then is withdrawn via conduit 13.
• the gasifier 10 is designed as fixed-bed reactor and includes a substantially cylindrical vertical reactor with external water jacket.
• the coal or biomass is introduced from above through a sluice into the solids distributor present in the interior of the reactor, whereby a fixed bed is formed, which rests on a rotary grate arranged in the lower region of the reactor 10. From this lower region oxygen and steam are also injected. Due to the ascending hot gases drying of the employed coal or biomass as well as desorption of the physisorbed gases takes place in the upper part of the gasifier 10. Below the drying zone the reaction zone is located, in whose upper part degassing of the coal or biomass takes place.
• the liquid stream obtained is recirculated to the ammonia recovery 25 via conduit 24.
• a Phenosolvan ® process can be provided (not shown in Fig. 2).
• conduit 26 then leads into the water treatment 30.
• the aqueous stream obtained there is divided into three streams. That stream which has the highest degree of purity is supplied via conduit 31 to a non-illustrated steam generation.
• the steam generated there can then either be used as heat carrier in the actual gasification process, e.g. for heating the educts, or be used for energy generation in a downstream turbine. In principle it is also conceivable to feed the stream of water as coolant into a cooling circuit. Possibly, a further non-illustrated purification of this stream will be necessary.
• conduit 37 the stream with the medium degree of purity is guided to the further ash treatment 12 and there serves as fluidizing agent.
• the introduction of make-up water thereby can be omitted completely.
• a further water purification 38 can also be provided for this stream in conduit 37.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Organic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Water Supply & Treatment (AREA)
• Environmental & Geological Engineering (AREA)
• Hydrology & Water Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• Industrial Gases (AREA)
• Processing Of Solid Wastes (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Carbon And Carbon Compounds (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

Family

ID=48236894

Family Applications (1)

Country Status (9)

Cited By (1)

Citations (10)

Family Cites Families (3)

• 2012
  • 2012-07-03 DE DE102012013139.9A patent/DE102012013139B4/de active Active
• 2013
  • 2013-04-23 UA UAA201413449A patent/UA114198C2/uk unknown
  • 2013-04-23 EA EA201401126A patent/EA029238B1/ru not_active IP Right Cessation
  • 2013-04-23 AU AU2013286304A patent/AU2013286304B2/en active Active
  • 2013-04-23 KR KR1020147033222A patent/KR102038725B1/ko active Active
  • 2013-04-23 WO PCT/EP2013/058337 patent/WO2014005738A1/en not_active Ceased
  • 2013-04-23 CN CN201390000581.8U patent/CN204803273U/zh not_active Expired - Lifetime
  • 2013-04-23 IN IN1869MUN2014 patent/IN2014MN01869A/en unknown
• 2014
  • 2014-09-25 ZA ZA2014/06985A patent/ZA201406985B/en unknown

Patent Citations (10)

Also Published As

Similar Documents

Legal Events