Classifications

• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/025—Reverse osmosis; Hyperfiltration
  • B01D61/026—Reverse osmosis; Hyperfiltration comprising multiple reverse osmosis steps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/04—Feed pretreatment
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B39/00—Cooling or quenching coke
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/04—Specific process operations in the feed stream; Feed pretreatment
• • 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
  • C10J2300/1861—Heat exchange between at least two process streams
  • C10J2300/1884—Heat exchange between at least two process streams with one stream being synthesis gas

Definitions

• the invention relates to a process for the treatment of waste water obtained in coal pyrolysis, the waste water after filtering, distillation and by means of reverse osmosis being separated into a low-salt permeate which can be recycled into the coking process and a concentrated salt solution and the concentrated salt solution in whole or in part in a hot, reducing atmosphere is split and the salts are separated.
• coal water treatment system can be planned differently. However, for all systems there is a fundamental need to remove the toxic substances in the wastewater to ecologically acceptable limit values.
• the concentrate obtained with this process technology is a salt solution in which the toxic pollutants such as chlorine, sulfate, nitrate, thiocyanates and thio sulfate to a cation, e.g. B. Na + are bound, if the fixed NH 3 is also to be stripped in the desorption system.
• DE-OS 35 32 390 provides for this to be returned to the coking process or to be worked up in a separate salt cracking plant with alkali recovery.
• the addition of the concentrated salt solution in the coking process can lead to problems with coking or to damage to the coke oven walls, especially with the simultaneous addition of larger amounts of water. Splitting in our own salt splitting plants requires considerable additional energy and equipment.
• the object of the invention is now to improve the above-mentioned method, in particular with regard to these problems and thus to propose an energy-saving and environmentally friendly method in which no process waste water has to be removed from the coking system.
• the use of an additional splitting plant for working up the concentrated salt solution can be dispensed with. It is also not necessary to heat the salt solution to a high reaction temperature with additional expensive energy. Instead, the sensible heat of the red-hot coke is used after leaving the coking chamber and, at the same time, a cracking gas containing high quality hydrogen and carbon monoxide is generated. The heat energy of the hot coke is converted into a valuable chemical energy by a water vapor conversion.
• the proposal according to the invention to split the toxic constituents of the coal water by means of the hot coke at 1,000 to 1,100 ° C. has the further advantages that
• the retentate of a reverse osmosis can be used without further concentration
• a dry coke aftertreatment for the purpose of dust elimination is not necessary since the small coke particles or the coke edges will react with the water vapor in the first step.
• FIGS. 1 and 2 The method principle of the invention is shown for example in FIGS. 1 and 2 and is to be described in more detail by means of a numerical example.
• Figure 1 shows the processing of the wastewater from the tar-water separation to the direct application of the salt solution on the hot coke.
• FIG. 2 shows a schematic diagram of gasification coke cooling that has been changed and specified more precisely than in FIG. 1.
• the water phase of the pyrolysis increases in quantity due to internal circulation wastewater flows to approx. 42 m (5) and is loaded with 500 kg of fixed and 146 kg of volatile ammonia salts as well as with 75 kg of phenols, 12 kg of pyridine bases and 3 kg of aromatic hydrocarbons and carboxylic acids.
• coal water and the recycle streams are freed from dispersed tar and solid particles in a gravel filter system (6) and then adjusted to a colloid index of ⁇ 1 in a filter system based on the principle of cross-flow filtration (10).
• the permeate (11) from the filtration (10) is 35 m 3 and is increased to 36 m 3 by adding 1 m 3 of condensate (12) from a sulfur processing process as a feed stream for the NH 3 stripper (13).
• the stripper (13) works on the principle of steam stripping by means of direct steam additions (15) of 6 t.
• the head of the stripper (13) leaves 1 t of steam (14), loaded with 142 kg of gases such as NH 3 , H 2 S, HCN etc. of the volatile NH 3 compounds, approx. 11 kg phenols, approx. 11 kg pyridine bases and about 2 kg of the aromatics to the deacidifier.
• gases such as NH 3 , H 2 S, HCN etc.
• gases such as NH 3 , H 2 S, HCN etc.
• Another 1 to 2 t of water vapor are removed from the middle section and used as stripping steam for the deacidifier.
• the wastewater (15h) from the stripper (13) is about 40 m and is still loaded with about 500 kg of salts, 64 kg of phenols and about 2 kg of pyridines and aromatics and has a pH of 7 to 8. According to Cooling to 30 ° C, the wastewater is divided into different fractions in a reverse osmosis system (RO system) (20) to (22) which works on the principle of fractionation.
• RO system reverse osmosis system
• Negative retention properties (accumulations of dissolved substances in the permeate) are possible, e.g. B. aqueous solutions of phenols and benzene.
• fractional reverse osmosis system according to the invention shown in FIG. 1 was developed using these rules.
• the pH of the stripped wastewater is adjusted to pH ⁇ 5 by adding a small amount of acid (16) and passes through a filter (18) for safety reasons.
• the first stage (20) of the membrane system is an RO module with a membrane based on cellulose acetate, whose retention values for the salts are> 93% and the phenols ⁇ 7%.
• 29 m 3 of permeate (23) are produced, which is loaded with 60 kg of phenols and 22 kg of salts.
• the retentate, ie the salt solution (32), in the amount of 11 m 3 is loaded with about 480 kg of salts and 4 kg
• the second stage (21) of the RO system works at a pH of 8 to 9, which is adjusted by adding a base (24).
• the membrane initial of this stage is based on polyamide, whose retention value for phenols is> 95% wearing.
• a retentate (30) of 3 m 3 is obtained, which is loaded with 57 kg phenols ( ⁇ 2% by weight).
• the phenols can either be obtained directly from this retentate (30) as product (31) or, as planned in this example, the retentate is additionally added to the cooling and rinsing water (4) and used in the raw gas quenching. In the condensation system, the phenols are then distributed into the tar and water phases according to the laws.
• the permeatroin (25) is 26 m 3 and is still loaded with 3 kg of phenols and 7 kg of salts and is raised as a feed stream for the third stage (22) of the RO system to a pH> 11.
• the third stage also works with a polyamide as the membrane base, the. Retention is so good under these conditions that a permeate stroin (28) of 25 t with less than 0.15 mg / 1 phenols and ⁇ 2 mg / 1 salts is produced.
• the retentate stream (29) of 1 m 3 is added to the retentate (30) from the second stage.
• the Permeatstroin (28) can be used as purified service water directly in the gas treatment system, e.g. B. as wash water for NH 3 washing or as a feed for the demineralization plant.
• the 11 m 3 salt solution (32) from the first RO stage (20) are loaded with approx. 480 kg salts and 4 kg phenols.
• the main proportions of the salts are NH 4 Cl, (NH 4 ) SO 4 , (NH 4 ) 2 S 2 O 3 and NH 4 CNS and are classified as highly toxic.
• the chlorine and sulfur enter the pyrolysis system via the coal and must be obtained in an ecologically acceptable form.
• the invention now offers the possibility, when using an existing energy source of pyrolysis, to obtain the remaining sulfur also as sulfuric acid or liquid sulfur and the chlorine z. B. to convert into a Ca compound.
• the invention is now the combination of the extraction of chemical energy from the thermal energy of the coke by a carbon conversion (C + H 2 O ⁇ CO + H 2 ) and a salt splitting analogously according to the rules NH 4 Cl ⁇ N 2 + H 2 + HCl,
• the hot coke (33) passes through a gasification cooling shaft (41) from top to bottom and has a prechamber (42) in front of the actual gasification zone for the compensation of the batch operation.
• the rectants are guided in countercurrent and partly in cocurrent.
• the countercurrent is achieved by a gas circuit (50), (38) or (40), the direct current by the salt solution (32) being sprayed directly onto the upper hot layer (1,000 to 1,100 ° C) of the coke ( Figure 1 ).
• the energy of the hot coke from 1,050 ° C to 400 ° C in the
• the order of magnitude of 28 Gcal is used in such a way that 5,360 kg C of the coke is converted into 7,900 Nm 3 CO and 11,900 Nm 3 H 2 by means of 9,560 kg water vapor and the ammonia salts are split be.
• HCl 11.8 gHCl or 1.9 g H 2 S per Nm 3 (wf). It can be further converted to hydrogen in a typical gas processing system.
• the HCl is expediently washed out with milk of lime and obtained as CaCl 2 , while the H 2 S may be operated in combination with the H 2 S absorption system of the coke oven gas.
• the 800 ° C. hot circulating gas (50) is split upstream of the waste heat boiler (51) and about half (45) countercurrently sprinkled with the preheated salt solution (32) of 11 t in a concentrator (44), the gas cools to approx. 200 ° C and 9.0 t of water evaporate.
• the moist circulation volume (48) increases to approx. 36,000 Nm and is introduced into the lower part of the cooling shaft (41).
• the concentrated salt solution (46) of 2.0 m 3 is sprayed onto the hot coke at 1,000 to 1,100 ° C in the upper part of the cooling shaft, the salts splitting.
• about 0.5 t of water is added to the system as gasification vapor (49).
• the reaction starts at 500 C and according to the laws, the gasification rate increases with increasing temperature.
• the temperature range of the coke from 300 to 500 ° C is used to heat the cycle gas and, if necessary, to evaporate make-up water.
• reaction steam All or part of this amount of steam can be added to the cycle gas as reaction steam (49).
• the excess steam is condensed outside the coke cooling in a closed system (57) to (61) and used as condensate in the overall process.
• the overall process technology of this invention is designed so that no process waste water has to be removed from the system.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Nanotechnology (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Environmental & Geological Engineering (AREA)
• Materials Engineering (AREA)
• Hydrology & Water Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• Combustion & Propulsion (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Industrial Gases (AREA)
• Physical Water Treatments (AREA)
• Heat Treatment Of Water, Waste Water Or Sewage (AREA)
• Coke Industry (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

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Cited By (4)

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• 1988
  • 1988-02-09 DE DE3803905A patent/DE3803905A1/de active Granted
• 1989
  • 1989-02-02 WO PCT/EP1989/000093 patent/WO1989007636A1/de not_active Ceased
  • 1989-02-02 JP JP1501719A patent/JPH03502464A/ja active Pending
  • 1989-02-02 AU AU30350/89A patent/AU3035089A/en not_active Abandoned
  • 1989-02-14 IN IN128/CAL/89A patent/IN171475B/en unknown

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