CN209685495U - A desulfurization wastewater recovery and crystalline salt purification system driven by waste heat - Google Patents

Abstract

A desulfurization wastewater recovery and crystalline salt purification system driven by waste heat belongs to the technical field of energy saving and sewage treatment of thermal power plants. The utility model adopts a variety of waste heat driving methods such as high-grade heat energy of the deaerator and the return water heating steam of the heating network, and the sensible heat waste heat of the high-temperature section of the flue gas. Salt separation, and the chlorine ions, suspended solids, high-valent ions and heavy metals in the desulfurization water are continuously separated from the circulation, and the recycled water after purification and conditioning, and the recovered water are returned to the desulfurization water circulation system, and the desulfurization circulation water is maintained. The water quality is always within the allowable range, so as to realize the self-sustaining operation of desulfurization circulating water; at the same time, high-purity sodium chloride can be recovered and used as raw material for chlor-alkali plants. The system significantly reduces the energy consumption and cost of zero discharge of sewage and realizes efficient resource utilization, and is especially suitable for joint operation of thermal power plants or heat source plants and chlor-alkali processes.

Description

A desulfurization wastewater recovery and crystalline salt purification system driven by waste heat

technical field

The utility model relates to a desulfurization wastewater recovery and crystal salt purification system driven by waste heat, which belongs to the technical field of energy saving and sewage treatment of thermal power plants.

Background technique

At present, a large number of wet desulfurization methods are used in the desulfurization treatment system of boiler exhaust in thermal power plants or heat source plants. This method needs to discharge more desulfurization wastewater, because the desulfurization water cycle absorbs and absorbs a large amount of reaction products due to contact with flue gas. The components contained in the flue gas make the composition of the low pool water of the desulfurization tower complex, highly corrosive, and easy to scale. The water quality of the spray circulating water meets the needs of the continuous and normal operation of the desulfurization process. However, this part of the discharged high-concentration desulfurization water belongs to hazardous waste water. It is usually mixed into the sewage treatment tank in the plant for unified treatment, which will increase the difficulty of the post-treatment process and cost more investment. If the part of the desulfurization wastewater can be treated separately Treatment will effectively reduce the difficulty and cost of other sewage treatment, but the separate treatment of desulfurization wastewater, and even the treatment of zero discharge, has difficulties such as long process chain, high investment, excessive energy consumption and cost of operation.

On the other hand, the miscellaneous salt produced is classified as hazardous waste because of its complex composition and contains many harmful substances such as COD and heavy metals. The number of species is extremely large, causing serious environmental hazards.

The above problems show that desulfurization wastewater and similar industrial hazardous wastewater have become more and more current industrial problems and important social issues.

Utility model content

The purpose and task of this utility model is to solve the problem that high-concentration hazardous waste water must be discharged in the above-mentioned desulfurization water cycle, but it must consume more clean water to supplement, and the energy consumption and operating costs of desulfurization waste water treatment are too high, and the solid salt produced belongs to Hazardous waste and other issues, using thermal method-based zero discharge of sewage and resource recovery technology, through a variety of waste heat driven methods, desulfurization sewage evaporative concentration reduction, thermal evaporation and salt separation crystallization, and chloride ions in desulfurized water Suspended solids, high-valent ions and heavy metals are continuously separated from the circulation to realize the recycling of water resources and contained material resources, while the reused water after purification and tempering and recovered water are returned to the desulfurization water circulation system to maintain desulfurization The water quality of circulating water is always within the allowable range, so as to realize the self-sustaining operation of desulfurization circulating water; at the same time, high-purity sodium chloride can be recovered and used as raw material for chlor-alkali plants, etc.

The specific description of the utility model is: a desulfurization wastewater recovery and crystallization salt purification system driven by waste heat, aiming at the enrichment of harmful components including chloride ions in the desulfurization water operation, which leads to corrosion and scaling, and even the desulfurization process cannot be carried out normally. Therefore, it is necessary to continuously discharge high-concentration hazardous waste water and continuously replenish new water for dilution. The utility model proposes a desulfurization wastewater recovery and crystal salt purification system driven by waste heat. After the desulfurization sewage water A passes through the desulfurization sewage pretreatment pool 3, it is sent to the oxidized calcification pool 4. The oxidized calcification pool 4 is provided with the inlet of oxidant O, the feeding port of lime milk and compound agent F, the feeding port of calcium sulfate K3, The discharge port and the treated water outlet of other solid salt K5, the treated water outlet of the oxidized calcification tank 4 are connected with the raw water inlet of the microfiltration membrane purification device 5, and the microfiltration membrane purification device 5 is provided with a feed inlet of lye CH, regeneration The outlet of sewage G3, the inlet of high concentrated water H and the outlet of treated water, the outlet of treated water of microfiltration membrane purification device 5 is connected with the raw water inlet of nanofiltration membrane salt separation device 6, the high concentrated water of nanofiltration membrane salt separation device 6 The outlet of H is connected to the inlet of the high concentration water H of the oxidized calcification tank 4, the purified water outlet of the nanofiltration membrane salt separation device 6 is connected to the raw water inlet of the waste heat evaporation crystallizer 7, and the waste heat evaporation crystallizer 7 is provided with a waste heat heat source J1 Inlet, outlet of waste heat heat source effluent J2, salt outlet of industrial grade sodium chloride K1, outlet of sewage secondary steam L, and outlet of mother liquor G4, among which the outlet of sewage secondary steam L of waste heat evaporation crystallizer 7 and waste heat recovery The high-temperature side inlet of the waste heat recovery unit 8+9 is connected, and the high-temperature side outlet of the waste heat recovery unit 8+9 is connected with the water collection pipe of the recycled clean water D.

The outlet of the desulfurization sewage water A of the tower bottom pool of the desulfurization tower 1 is connected with the inlet of the spray device 22 of the flue gas evaporator 20, and the outlet of the desulfurization concentrated water G5 of the flue gas evaporator 20 is connected with the miscellaneous water of the desulfurization sewage pretreatment pool 3. The concentrated water inlet is connected, the flue gas inlet pipe 21 of the flue gas evaporator 20 is connected with the flue of the high-temperature exhaust gas Y from the boiler or dust collector, and the medium-temperature flue gas Y0 of the flue gas evaporator 20 passes through the flue gas outlet pipe 23 and desulfurization The desulfurization inlet of tower 1 is connected to the inlet of Y1.

The inlet of the oxidizing agent O of the oxidation calcification pool 4 is connected with the outlet of the oxidation device 11 .

The outlet of the suspended high-concentration water G1 of the desulfurization sewage pretreatment tank 3 is connected to the raw water inlet of the filter press 10. The outlet of the regenerated sewage G3 of the membrane purification device 5 is connected to the outlet of the mother liquid G4 of the waste heat evaporation crystallizer 7, and the filter press 10 is provided with a discharge outlet of the sludge K2.

The outlet of the industrial-grade sodium chloride K1 of the waste heat evaporation crystallizer 7 is connected to the feed port of the crystallization salt repurification device 71, and the crystallization salt repurification device 71 is provided with an inlet for repurifying the waste heat heat source J3 and a repurification waste heat heat source outlet water J4 The export and the export of high-purity industrial-grade sodium chloride K4, the crystallization salt repurification device 71 adopts the thermal process and control method and structure of large-grain crystallization into salt, and adopts a positive pressure one-stage heat exchange structure and a positive pressure multi-stage heat exchange structure. Thermal structure, negative pressure one-stage evaporation heat exchange structure or negative pressure multi-stage evaporation heat exchange structure.

Waste heat recovery unit 8+9 includes deaerator and process water waste heat heater 8, the low-temperature side inlet of deaerator and process water waste heat heater 8 communicates with deaerator and process water inlet water M1, deaerator And the low-temperature side outlet of the process water waste heat heater 8 is connected with the deaerator and process water inlet and outlet M2, and the high-temperature side inlet of the deaerator and process water waste heat heater 8 is connected with the sewage secondary steam of the waste heat evaporation crystallizer 7 The outlet of L is connected, and the outlet of the first drainage D1 on the high temperature side of the deaerator and the process water waste heat heater 8 is connected with the water collection pipe of reused clean water D.

The waste heat recovery unit 8+9 includes the heat network return water waste heat heater 9, the low-temperature side inlet of the heat network return water waste heat heater 9 communicates with the heat network return water inlet water N1, and the heat network return water waste heat heater 9 The low-temperature side outlet is connected to the return water inlet and outlet N2 of the heating network, the high-temperature side inlet of the heating network return water waste heat heater 9 is connected to the outlet of the sewage secondary steam L of the waste heat evaporation crystallizer 7, and the heat network return water waste heat heater The outlet of the second drainage D2 on the high temperature side of 9 is connected to the water collection pipe of reused clear water D.

The waste heat evaporation crystallizer 7 adopts the thermal process and control method and structure of large particle crystallization into salt, and adopts a positive pressure one-stage heat exchange structure, a positive pressure multi-stage heat exchange structure, a negative pressure one-stage evaporation heat exchange structure or a negative pressure Multi-stage evaporative heat exchange structure.

The utility model solves the problem that a large amount of high-concentration hazardous waste water needs to be discharged during the wet desulfurization process of boiler exhaust smoke, and realizes a desulfurization water circulation process that does not need to be discharged outside and can be operated in a self-sustaining cycle. Clean water reuse saves the need for water replenishment, and improves the effect of the desulfurization process by supplementing alkaline water to the desulfurization circulating water. It also recovers high-purity industrial-grade sodium chloride, calcium sulfate and other resources, and at the same time greatly saves artificial energy consumption and other resources. running costs. Among them, compared with conventional zero-discharge sewage and hazardous waste salt purification and recovery technologies, it can reduce the artificial energy demand by about 90%, greatly reduce energy consumption and reduce operating costs by an order of magnitude. It has become the most thermal power plant, boiler room and related industries A brand-new technical method of comprehensive sewage treatment and resource recovery that users can afford to build and use. The utility model can make the main heat source and power system of the coal-fired boiler realize the transformation from a high-pollution and high-discharge mode to a clean production-type green power plant mode with zero discharge of process sewage and significantly reduced water resource consumption, and has both technical and economic values And environmental protection, social effect.

The method significantly reduces the energy consumption and cost of zero discharge of sewage and realizes high-efficiency resource utilization, and is especially suitable for the joint operation of a thermal power plant or a heat source plant and a chlor-alkali process. At the same time, the technical method and its device and engineering implementation plan designed by the utility model can also be further extended to similar desulfurization processes in other industries and even other related hazardous waste treatment processes, and have more general industrial application value and social and economic benefits .

Description of drawings

Fig. 1 is a schematic diagram of the system of the present utility model.

The numbers and names of the parts in Figure 1 are as follows.

Desulfurization tower 1, desulfurization sewage pretreatment pool 3, oxidized calcification pool 4, microfiltration membrane purification device 5, nanofiltration membrane salt separation device 6, waste heat evaporation crystallizer 7, crystal salt repurification device 71, deaerator and process water Waste heat heater 8, heat network return water waste heat heater 9, filter press 10, oxidation device 11, flue gas evaporator 20, flue gas inlet pipe 21, spray device 22, flue gas outlet pipe 23, desulfurization sewage water A , desulfurization circulating water B, mixed influent water B1, desulfurization replenishment water C, reused clear water D, high temperature side first drainage D1, high temperature side second drainage D2, milk of lime and compound agent F, miscellaneous sewage G, suspended high concentration water G1 , Purified water G2 of filter press 10, regenerated sewage G3, mother liquor G4, desulfurization concentrated water G5, high concentration water H, waste heat source J1, waste heat source water outlet J2, repurified waste heat source J3, repurified waste heat source water outlet J4, industrial Grade sodium chloride K1, sludge K2, calcium sulfate K3, high-purity industrial grade sodium chloride K4, other solid salt K5, sewage secondary steam L, deaerator and process water inlet water M1, deaerator and Process water inlet water M2, heating network return water inlet water N1, heating network return water inlet water removal N2, oxidant O, high temperature smoke exhaust Y, medium temperature flue gas Y0, desulfurization smoke inlet Y1, desulfurization smoke exhaust Y2 .

Detailed ways

Fig. 1 is a schematic diagram of the system of the present utility model.

The specific embodiment of the utility model is as follows: a desulfurization wastewater recovery and crystallization salt purification system driven by waste heat, the desulfurization sewage water A from the tower bottom pool of the desulfurization tower 1 passes through the desulfurization sewage pretreatment pool 3, and then is sent to the oxidation The calcification pool 4, the oxidative calcification pool 4 is provided with the inlet of oxidant O, the feeding port of milk of lime and compound agent F, the discharge port of calcium sulfate K3, the discharge port of other solid salt K5, the outlet of treated water, and the oxidative calcification pool 4 The outlet of the treated water is connected with the raw water inlet of the microfiltration membrane purification device 5, and the microfiltration membrane purification device 5 is provided with the feed inlet of the lye CH, the outlet of the regenerated sewage G3, the inlet of the high concentration water H and the outlet of the treated water, and the microfiltration membrane purification device 5 The treated water outlet of the filter membrane purification device 5 is connected with the raw water inlet of the nanofiltration membrane salt separation device 6, and the outlet of the high concentration water H of the nanofiltration membrane salt separation device 6 is connected with the inlet of the high concentration water H of the oxidized calcification tank 4, The purified water outlet of the nanofiltration membrane salt separation device 6 is connected to the raw water inlet of the waste heat evaporation crystallizer 7, and the waste heat evaporation crystallizer 7 is provided with an inlet of waste heat heat source J1, an outlet of waste heat heat source water outlet J2, and an outlet of industrial grade sodium chloride K1. Salt outlet, outlet of sewage secondary steam L and mother liquid G4 outlet, wherein the outlet of sewage secondary steam L of waste heat evaporation crystallizer 7 is connected to the high temperature side inlet of waste heat recovery unit 8+9, waste heat recovery unit 8+ The high-temperature side outlet of 9 is connected with the water collecting pipe of reusing clear water D.

The outlet of the desulfurization sewage water A of the tower bottom pool of the desulfurization tower 1 is connected with the inlet of the spray device 22 of the flue gas evaporator 20, and the outlet of the desulfurization concentrated water G5 of the flue gas evaporator 20 is connected with the miscellaneous water of the desulfurization sewage pretreatment pool 3. The concentrated water inlet is connected, the flue gas inlet pipe 21 of the flue gas evaporator 20 is connected with the flue of the high-temperature exhaust gas Y from the boiler or dust collector, and the medium-temperature flue gas Y0 of the flue gas evaporator 20 passes through the flue gas outlet pipe 23 and desulfurization The desulfurization inlet of tower 1 is connected to the inlet of Y1.

The inlet of the oxidizing agent O of the oxidation calcification pool 4 is connected with the outlet of the oxidation device 11 .

The outlet of the suspended high-concentration water G1 of the desulfurization sewage pretreatment tank 3 is connected to the raw water inlet of the filter press 10. The outlet of the regenerated sewage G3 of the membrane purification device 5 is connected to the outlet of the mother liquid G4 of the waste heat evaporation crystallizer 7, and the filter press 10 is provided with a discharge outlet of the sludge K2.

The outlet of the industrial-grade sodium chloride K1 of the waste heat evaporation crystallizer 7 is connected to the feed port of the crystallization salt repurification device 71, and the crystallization salt repurification device 71 is provided with an inlet for repurifying the waste heat heat source J3 and a repurification waste heat heat source outlet water J4 The export and the export of high-purity industrial-grade sodium chloride K4, the crystallization salt repurification device 71 adopts the thermal process and control method and structure of large-grain crystallization into salt, and adopts a positive pressure one-stage heat exchange structure and a positive pressure multi-stage heat exchange structure. Thermal structure, negative pressure one-stage evaporation heat exchange structure or negative pressure multi-stage evaporation heat exchange structure.

Waste heat recovery unit 8+9 includes deaerator and process water waste heat heater 8, the low-temperature side inlet of deaerator and process water waste heat heater 8 communicates with deaerator and process water inlet water M1, deaerator And the low-temperature side outlet of the process water waste heat heater 8 is connected with the deaerator and process water inlet and outlet M2, and the high-temperature side inlet of the deaerator and process water waste heat heater 8 is connected with the sewage secondary steam of the waste heat evaporation crystallizer 7 The outlet of L is connected, and the outlet of the first drainage D1 on the high temperature side of the deaerator and the process water waste heat heater 8 is connected with the water collection pipe of reused clean water D.

The waste heat recovery unit 8+9 includes the heat network return water waste heat heater 9, the low-temperature side inlet of the heat network return water waste heat heater 9 communicates with the heat network return water inlet water N1, and the heat network return water waste heat heater 9 The low-temperature side outlet is connected to the return water inlet and outlet N2 of the heating network, the high-temperature side inlet of the heating network return water waste heat heater 9 is connected to the outlet of the sewage secondary steam L of the waste heat evaporation crystallizer 7, and the heat network return water waste heat heater The outlet of the second drainage D2 on the high temperature side of 9 is connected to the water collection pipe of reused clear water D.

The waste heat evaporation crystallizer 7 adopts the thermal process and control method and structure of large particle crystallization into salt, and adopts a positive pressure one-stage heat exchange structure, a positive pressure multi-stage heat exchange structure, a negative pressure one-stage evaporation heat exchange structure or a negative pressure Multi-stage evaporative heat exchange structure.

It should be noted that this utility model proposes how to comprehensively solve the problem of reuse of water resources and material resources of desulfurization hazardous waste water by using heat exchange methods, waste heat evaporation and energy cascade utilization methods, and according to this overall solution There may be different specific implementation measures and specific implementation devices with different structures, the above specific implementation is only one of them, any other similar simple deformation implementation, for example, involves the selection of the waste heat recovery heat exchanger type and the number of units change; the type of waste heat heat source is low-pressure steam below 100°C, positive pressure steam above atmospheric pressure, or waste heat hot water, flue gas and other waste heat types; only a part of the claims are implemented but not all of the waste heat drive The evaporation method, or the sewage pretreatment process, or the post-treatment process, etc.; or combine the sewage pretreatment tank with the desulfurization sewage pretreatment tank, and simply combine or separate the design of the treatment equipment or process; or use simple replacement of different Type, performance and quality of membranes or other sewage treatment devices for sewage treatment in the corresponding link; or other deformation methods that ordinary professionals can think of; or apply the technology to the same or similar method, system and structure Similar desulfurization water treatment and application occasions in other industries except coal-fired boiler wet desulfurization wastewater treatment all fall into the scope of protection of the utility model.

Claims (8)

1. a kind of using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, which is characterized in that come from desulfurizing tower (1) Tower bottom pond desulfurization sewerage (A) after desulfurization blowdown pretreatment pool (3), be sent to oxidation calcification pond (4), calcium oxide Change pond (4) be provided with the import of oxidant (O), the feeding port of milk of lime and composite drug (F), calcium sulfate (K3) discharge port, Discharge port, the processing water out of other solid salts (K5), aoxidize the processing water out and micro-filtration film purifying device of calcification pond (4) (5) original water inlet is connected, micro-filtration film purifying device (5) be provided with the feed inlet of lye (CH), regenerated sewage (G3) outlet, The import of high concentrated water (H) and processing water out, the processing water out and nanofiltration membrane of micro-filtration film purifying device (5) divide salt device (6) Original water inlet be connected, nanofiltration membrane divides the high concentrated water (H) of outlet and oxidation calcification pond (4) of the high concentrated water (H) of salt device (6) Import is connected, and nanofiltration membrane divides the treated water outlet of salt device (6) and the original water inlet of waste heat crystallizing evaporator (7) to be connected, waste heat The import for heat source (J1) that have surplus heat, the outlet of waste heat heat source water outlet (J2), industrial grade sodium chloride (K1) is arranged in crystallizing evaporator (7) Salt outlet, the outlet of sewage secondary steam (L) and the outlet of mother liquor (G4), the wherein sewage two of waste heat crystallizing evaporator (7) The outlet of secondary steam (L) is connected with the high temperature side-entrance of waste-heat recoverer component (8,9), the height of waste-heat recoverer component (8,9) Warm side outlet is connected with the collector pipe of reuse clear water (D).

2. as described in claim 1 using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, it is characterised in that The outlet of the desulfurization sewerage (A) in the tower bottom pond of the desulfurizing tower (1) and the spray equipment (22) of flue gas evaporator (20) Import be connected, the miscellaneous concentrated water of the outlet of the desulfurization condensed water (G5) of flue gas evaporator (20) and desulfurization blowdown pretreatment pool (3) Import is connected, the flue of the flue gas inlet tube (21) of flue gas evaporator (20) and the high-temperature smoke discharging (Y) from boiler or deduster It is connected, the medium temperature flue gas (Y0) of flue gas evaporator (20) is by the desulfurization of smoke outlet tube (23) and desulfurizing tower (1) into cigarette (Y1) Import be connected.

3. as described in claim 1 using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, it is characterised in that The import of the oxidant (O) in the oxidation calcification pond (4) is connected with the discharge port of oxidation unit (11).

4. as described in claim 1 using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, it is characterised in that The outlet of the high concentrated water of suspension (G1) of the desulfurization blowdown pretreatment pool (3) is connected with the original water inlet of filter press (10), takes off The import of the miscellaneous sewage (G) of sulphur blowdown pretreatment pool (3) is purified with purified water (G2) import of filter press (10), microfiltration membranes respectively The outlet of the regenerated sewage (G3) of device (5), the outlet of the mother liquor (G4) of waste heat crystallizing evaporator (7) are connected, filter press (10) It is provided with the outlet of sludge (K2).

5. as described in claim 1 using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, it is characterised in that The feed inlet of the outlet of the industrial grade sodium chloride (K1) of the waste heat crystallizing evaporator (7) and crystal salt purification device (71) again It is connected, purification device (71) is provided with again the import of purification waste heat heat source (J3), purification waste heat heat source water outlet again to crystal salt again (J4) outlet of outlet and high-purity technical grade sodium chloride (K4), crystal salt again purification device (71) using large particle crystal at The thermal technology's process and control mode and structure of salt, and use positive pressure level-one heat exchange structure, positive pressure multi-stage heat exchanger structure, negative pressure level-one Evaporation and heat-exchange structure or negative pressure multistage evaporation and heat-exchange structure.

6. as described in claim 1 using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, it is characterised in that The waste-heat recoverer component (8,9) includes oxygen-eliminating device and process water heater heated by waste heat (8), and oxygen-eliminating device and process water waste heat add The low temperature side-entrance of hot device (8) is communicated with oxygen-eliminating device and process water water inlet water (M1), oxygen-eliminating device and process water heater heated by waste heat (8) low temperature side outlet and oxygen-eliminating device and process water water inlet go water (M2) to communicate, oxygen-eliminating device and process water heater heated by waste heat (8) High temperature side-entrance is connected with the outlet of the sewage secondary steam (L) of waste heat crystallizing evaporator (7), and oxygen-eliminating device and process water waste heat add The outlet that the high temperature side first of hot device (8) drains (D1) is connected with the collector pipe of reuse clear water (D).

7. as described in claim 1 using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, it is characterised in that The waste-heat recoverer component (8,9) includes heat supply network return water heater heated by waste heat (9), heat supply network return water heater heated by waste heat (9) it is low Warm side-entrance is communicated with heat supply network return water water inlet water (N1), and the low temperature side outlet and heat supply network of heat supply network return water heater heated by waste heat (9) return Water water inlet goes water (N2) to communicate, the high temperature side-entrance of heat supply network return water heater heated by waste heat (9) and the sewage of waste heat crystallizing evaporator (7) The outlet of secondary steam (L) is connected, and the outlet and reuse of the draining of high temperature side second (D2) of heat supply network return water heater heated by waste heat (9) are clear The collector pipe of water (D) is connected.

8. as described in claim 1 using the desulfurization wastewater recycling of waste heat driving and crystal salt purification system, it is characterised in that The waste heat crystallizing evaporator (7) uses large particle crystal at the thermal technology's process and control mode and structure of salt, and using just Press level-one heat exchange structure, positive pressure multi-stage heat exchanger structure, negative pressure level-one evaporation and heat-exchange structure or negative pressure multistage evaporation and heat-exchange structure.