CN209338304U - A Waste Heat Evaporative Desulfurization Wastewater Zero Discharge System - Google Patents

Abstract

A waste heat evaporative desulfurization waste water zero discharge system belongs to the technical field of energy saving and sewage treatment of thermal power plants. Aiming at the complex components of desulfurized water, strong corrosion, easy scaling, etc., which lead to long treatment chains, high investment, excessive operating energy consumption and high cost of zero discharge, etc., the utility model adopts a deaerator and a heating network return water heating steam High-grade heat energy, sensible heat and waste heat in the high-temperature section of flue gas and other waste heat driving methods, for desulfurization sewage evaporative concentration reduction, thermal evaporation and salt separation and crystallization, and remove chloride ions, suspended solids and high-valent ions in desulfurization water 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 the recycled clean water are returned to the desulfurization water circulation system, and the water quality of the desulfurization circulating water is always maintained. Within the allowable range, the self-sustaining operation of the desulfurization circulating water is realized, which not only eliminates the desulfurization sewage, but also greatly reduces the energy consumption and cost of operation.

Description

A Waste Heat Evaporative Desulfurization Wastewater Zero Discharge System

technical field

The utility model relates to a waste heat evaporation type desulfurization waste water zero discharge system, 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 have difficulties such as long process chain, high investment, excessive energy consumption and cost of operation, and therefore become the current industry-wide sexual conundrum.

Utility model content

The purpose and task of this utility model is to solve the problems that high-concentration hazardous waste water must be discharged in the above-mentioned desulfurization water circulation, but it must consume more clean water to supplement, and the energy consumption and operating costs of desulfurization wastewater treatment are too high. The sewage zero discharge and resource recovery technology of the new method, through a variety of waste heat driven methods, desulfurization sewage evaporative concentration reduction, thermal evaporation and salt separation and crystallization, and chloride ions, suspended solids, high-valent ions and heavy metals in desulfurization water Continuously separate from the circulation to realize the recycling of water resources and contained material resources, and the recycled water after purification and conditioning, and the recovered water are all returned to the desulfurization water circulation system, and the water quality of the desulfurization circulating water is always within the allowable range , so as to realize the self-sustaining operation of desulfurization circulating water.

The specific description of the utility model is: a waste heat evaporative desulfurization waste water zero discharge system, which is characterized in that the desulfurization sewage water A from the bottom pool of the desulfurization tower 1 is sent to the mixed water pretreatment after passing through the desulfurization sewage pool 3 Pool 4, mixed water pretreatment pool 4 is provided with the inlet of oxidant O, the import of miscellaneous sewage G, the outlet of suspended high concentration water G1, the outlet of treated water, the outlet of treated water in mixed water pretreatment pool 4 and the outlet of ultrafiltration device 5 The raw water inlet is connected, the treated water outlet of the ultrafiltration device 5 is connected with the raw water inlet of the salt separation device 6, the purified water outlet of the salt separation device 6 is connected with 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 The inlet of J1, the outlet of waste heat heat source water outlet J2, the salt outlet of industrial grade sodium chloride K1, the outlet of sewage secondary steam L and the outlet of mother liquor G4, wherein the outlet of sewage secondary steam L of waste heat evaporation crystallizer 7 is connected with The high-temperature side inlets of the waste heat recovery components 8 and 9 are connected, the high-temperature side outlets of the waste heat recovery components 8 and 9 are connected with the water collection pipes of recycled clear water D, and the high-concentration water H outlet of the salt separation device 6 is connected with the high-concentration water purification The raw water inlet of the pool 2 is connected, and the high-concentration water purification pool 2 is equipped with a feeding port for lime milk and chemical agent F, a feeding port for calcium sulfate and solid salt K3, and an outlet for purifying alkaline water E, in which the purifying alkaline water E After the outlet of is mixed with the desulfurization circulating water B, it is connected with the inlet of the desulfurization make-up water C, and is connected with the inlet of the mixed water B1 of the spraying device of the desulfurization tower 1.

The outlet of the desulfurization sewage water A in the pool at the bottom of the desulfurization tower 1 is connected to 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 to the miscellaneous concentrated water in the desulfurization sewage tank 3 The inlet is connected, the flue gas inlet pipe 22 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 is connected to the desulfurization tower 1 through the flue gas outlet pipe 23 The desulfurization inlet smoke Y1 is connected to the inlet.

The inlet of the oxidizing agent O of the mixed water pretreatment tank 4 is connected with the outlet of the oxidation device 11 .

The outlet of the suspended high-concentration water G1 of the mixed water pretreatment tank 4 is connected to the raw water inlet of the filter press 10, and the purified water G2 of the filter press 10 is connected to the inlet of the miscellaneous sewage G of the mixed water pretreatment tank 4. 10 is provided with a discharge port for sludge K2.

The outlet of the regenerated sewage G3 of the ultrafiltration device 5 is connected with the inlet of the miscellaneous sewage G of the mixed water pretreatment tank 4 .

The outlet of the mother liquor G4 of the waste heat evaporating crystallizer 7 is connected to the mother liquor inlet of the mother liquor waste heat drying device 71, and the mother liquor waste heat drying device 71 is provided with an inlet of the waste heat source J3 for drying, an outlet of the water outlet J4 of the waste heat source for drying and solid waste of the mother liquid At the outlet of K4, the mother liquor waste heat drying device 71 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 evaporation heat exchange structure.

The waste heat recovery components 8 and 9 include a deaerator and a process water waste heat heater 8, and the low-temperature side inlet of the deaerator and process water waste heat heater 8 communicates with the water inlet of the deaerator or the water inlet of the process water M1. The low-temperature side outlet of the deaerator and process water waste heat heater 8 is connected to the deaerator water inlet or the process water inlet and outlet M2, and the high-temperature side inlet of the deaerator and process water waste heat heater 8 is connected to the waste heat evaporation crystallizer 7 The outlet of the sewage secondary steam L is connected, 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 to the water collection pipe of the reused clean water D, and the water collection pipe of the reused clean water D is connected to the desulfurization replenishment water C The imports are connected, or they are not connected.

The waste heat recovery components 8 and 9 include 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 the reused clean water D, and the water collection pipe of the reused clean water D is connected to the inlet of the desulfurization replenishment water C, or not connected.

The salt separating device 6 adopts a nanofiltration membrane structure.

The waste heat evaporation crystallizer 7 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 evaporation 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 replenishment, and improves the effect of the desulfurization process by supplementing alkaline water to the desulfurization circulating water. It also recovers industrial-grade sodium chloride, calcium sulfate and other resources, and at the same time greatly saves artificial energy consumption and operating costs. . Among them, compared with conventional zero discharge of sewage and hazardous waste salt purification and recovery technology, it can reduce the demand for artificial energy by about 90%, greatly reduce energy consumption and reduce operating costs by an order of magnitude. 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.

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, high concentration water purification tank 2, desulfurization sewage discharge tank 3, mixed water pretreatment tank 4, ultrafiltration device 5, salt separation device 6, waste heat evaporation crystallizer 7, mother liquor waste heat drying 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 exhaust Sewage A, desulfurization circulating water B, mixed influent water B1, desulfurization replenishment water C, reused clean water D, high temperature side first drainage D1, high temperature side second drainage D2, purified alkaline water E, lime milk and chemical agents F, miscellaneous Sewage G, suspended high-concentration water G1, purified water from filter press 10 G2, regenerated sewage G3, mother liquor G4, desulfurization concentrated water G5, high-concentration water H, waste heat source J1, waste heat source water outlet J2, drying waste heat source J3, Dry waste heat source water J4, industrial grade sodium chloride K1, sludge K2, calcium sulfate and solid salt K3, mother liquor solid waste K4, sewage secondary steam L, deaerator or process water inlet water M1, Deaerator inlet water or process water inlet and outlet M2, heating network return water inlet and incoming water N1, heating network return water inlet and outlet N2, oxidant O, high-temperature exhaust smoke Y, medium-temperature flue gas Y0, desulfurization smoke inlet Y1, desulfurization and 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 waste heat evaporative desulfurization waste water zero discharge system, the desulfurization sewage water A from the pool at the bottom of the desulfurization tower 1 is sent to the mixed water pretreatment pool 4 after passing through the desulfurization sewage pool 3, The mixed water pretreatment tank 4 is provided with the inlet of the oxidant O, the inlet of the miscellaneous sewage G, the outlet of the suspended high concentration water G1, and the outlet of the treated water, and the treated water outlet of the mixed water pretreatment tank 4 is connected with the raw water inlet of the ultrafiltration device 5 , the treated water outlet of the ultrafiltration device 5 is connected with the raw water inlet of the salt separator 6, the purified water outlet of the salt separator 6 is connected with 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 , the outlet of waste heat source water J2, the salt outlet of industrial grade sodium chloride K1, the outlet of sewage secondary steam L and the outlet of mother liquor G4, wherein the outlet of sewage secondary steam L of waste heat evaporation crystallizer 7 and waste heat recovery device The high-temperature side inlets of components 8 and 9 are connected, the high-temperature side outlets of waste heat recovery components 8 and 9 are connected with the water collection pipe of reused clear water D, the high-concentrated water H outlet of the salt separation device 6 is connected with the high-concentrated water purification tank 2 The raw water inlet is connected, and the high-concentration water purification tank 2 is provided with a feeding port for lime milk and chemical agent F, a discharge port for calcium sulfate and solid salt K3, and an outlet for purifying alkaline water E, wherein the outlet for purifying alkaline water E is connected to After the desulfurization circulating water B is mixed, it is connected with the inlet of the desulfurization make-up water C, and connected with the inlet of the mixed water B1 of the spraying device of the desulfurization tower 1 .

The outlet of the desulfurization sewage water A in the pool at the bottom of the desulfurization tower 1 is connected to 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 to the miscellaneous concentrated water in the desulfurization sewage tank 3 The inlet is connected, the flue gas inlet pipe 22 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 is connected to the desulfurization tower 1 through the flue gas outlet pipe 23 The desulfurization inlet smoke Y1 is connected to the inlet.

The inlet of the oxidizing agent O of the mixed water pretreatment tank 4 is connected with the outlet of the oxidation device 11 .

The outlet of the suspended high-concentration water G1 of the mixed water pretreatment tank 4 is connected to the raw water inlet of the filter press 10, and the purified water G2 of the filter press 10 is connected to the inlet of the miscellaneous sewage G of the mixed water pretreatment tank 4. 10 is provided with a discharge port for sludge K2.

The outlet of the regenerated sewage G3 of the ultrafiltration device 5 is connected with the inlet of the miscellaneous sewage G of the mixed water pretreatment tank 4 .

The outlet of the mother liquor G4 of the waste heat evaporating crystallizer 7 is connected to the mother liquor inlet of the mother liquor waste heat drying device 71, and the mother liquor waste heat drying device 71 is provided with an inlet of the waste heat source J3 for drying, an outlet of the water outlet J4 of the waste heat source for drying and solid waste of the mother liquid At the outlet of K4, the mother liquor waste heat drying device 71 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 evaporation heat exchange structure.

The waste heat recovery components 8 and 9 include a deaerator and a process water waste heat heater 8, and the low-temperature side inlet of the deaerator and process water waste heat heater 8 communicates with the water inlet of the deaerator or the water inlet of the process water M1. The low-temperature side outlet of the deaerator and process water waste heat heater 8 is connected to the deaerator water inlet or the process water inlet and outlet M2, and the high-temperature side inlet of the deaerator and process water waste heat heater 8 is connected to the waste heat evaporation crystallizer 7 The outlet of the sewage secondary steam L is connected, 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 to the water collection pipe of the reused clean water D, and the water collection pipe of the reused clean water D is connected to the desulfurization replenishment water C The imports are connected, or they are not connected.

The waste heat recovery components 8 and 9 include 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 the reused clean water D, and the water collection pipe of the reused clean water D is connected to the inlet of the desulfurization replenishment water C, or not connected.

The salt separating device 6 adopts a nanofiltration membrane structure.

The waste heat evaporation crystallizer 7 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 evaporation 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 tank, and simply combine or separate the design of the treatment equipment or process; or simply replace different types, Performance and quality of the membrane or other sewage treatment equipment for the corresponding link of sewage treatment; or other deformation methods that ordinary professionals can think of; or apply the same or similar method, system and structure to the combustion Similar desulfurization water treatment and application occasions in other industries other than coal boiler wet desulfurization wastewater treatment all fall into the protection scope of the present utility model.

Claims (10)

1. A waste heat evaporative desulfurization waste water zero discharge system is characterized in that, after the desulfurization sewage (A) from the bottom pool of the desulfurization tower (1) passes through the desulfurization sewage pool (3), it is sent to the mixed water pretreatment Pool (4), mixed water pretreatment pool (4) is provided with the import of oxidant (O), the import of miscellaneous sewage (G), the outlet of suspended high concentration water (G1), the outlet of treated water, the mixed water pretreatment pool ( 4) the treated water outlet is connected with the raw water inlet of the ultrafiltration device (5), the treated water outlet of the ultrafiltration device (5) is connected with the raw water inlet of the salt separation device (6), and the purified water outlet of the salt separation device (6) is It is connected with the raw water inlet of the waste heat evaporation crystallizer (7), and the waste heat evaporation crystallizer (7) is provided with the inlet of waste heat source (J1), the outlet of waste heat source water (J2), and the outlet of industrial grade sodium chloride (K1) outlet, the outlet of sewage secondary steam (L) and the outlet of mother liquor (G4), wherein the outlet of sewage secondary steam (L) of waste heat evaporation crystallizer (7) is connected with the high temperature side of waste heat recovery unit (8, 9) The inlet is connected, 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), and the outlet of the high-concentration water (H) of the salt separation device (6) is connected with the high-concentration water purification tank ( 2) is connected to the raw water inlet, and the high-concentration water purification tank (2) is equipped with a feed port for lime milk and chemical agents (F), a discharge port for calcium sulfate and solid salt (K3), and a port for purifying alkaline water (E) The outlet, where the outlet of the purified alkaline water (E) is mixed with the desulfurization circulating water (B), connected to the inlet of the desulfurization make-up water (C), and mixed with the water (B1) of the spray device of the desulfurization tower (1) The import is connected. 2. The waste heat evaporative desulfurization waste water zero discharge system according to claim 1, characterized in that the outlet of the desulfurization sewage (A) in the bottom pool of the desulfurization tower (1) is connected to the flue gas evaporator (20) The inlet of the spraying device (22) is connected, the outlet of the desulfurization concentrated water (G5) of the flue gas evaporator (20) is connected with the miscellaneous concentrated water inlet of the desulfurization sewage tank (3), and the flue gas evaporator (20) The gas inlet pipe (21) is connected to 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 the desulfurization tower ( 1) The inlet of desulfurization flue gas (Y1) is connected. 3. The waste heat evaporative desulfurization waste water zero discharge system as claimed in claim 1, characterized in that the inlet of the oxidant (O) of the mixed water pretreatment tank (4) is connected to the outlet of the oxidation device (11) . 4. The waste heat evaporative desulfurization waste water zero discharge system as claimed in claim 1, characterized in that the outlet of the suspended high concentration water (G1) of the mixed water pretreatment tank (4) is connected with the outlet of the filter press (10) The raw water inlet is connected, the purified water (G2) of the filter press (10) is connected with the inlet of the miscellaneous sewage (G) of the mixed water pretreatment tank (4), and the filter press (10) is provided with a sludge (K2) discharge Export. 5. The waste heat evaporative desulfurization waste water zero discharge system as claimed in claim 1, characterized in that the outlet of the regenerated sewage (G3) of the ultrafiltration device (5) and the miscellaneous sewage of the mixed water pretreatment tank (4) (G) The inlet is connected. 6. The waste heat evaporative desulfurization waste water zero discharge system according to claim 1, characterized in that the outlet of the mother liquor (G4) of the waste heat evaporation crystallizer (7) and the mother liquor inlet of the mother liquor waste heat drying device (71) Connected, the mother liquor waste heat drying device (71) is provided with the inlet of the drying waste heat heat source (J3), the outlet of the drying waste heat heat source outlet water (J4) and the outlet of the mother liquor solid waste (K4), and the mother liquor waste heat drying device (71) Positive pressure one-stage heat exchange structure, positive pressure multi-stage heat exchange structure, negative pressure one-stage evaporation heat exchange structure or negative pressure multi-stage evaporation heat exchange structure are adopted. 7. The waste heat evaporative desulfurization waste water zero discharge system according to claim 1, characterized in that the waste heat recovery unit (8, 9) includes a deaerator and a process water waste heat heater (8), and the deaerator and the low-temperature side inlet of the process water waste heat heater (8) communicates with the deaerator inlet water or the process water inlet water (M1), and the low-temperature side outlet of the deaerator and process water waste heat heater (8) is connected with the deaerator The inlet of the deaerator and process water waste heat heater (8) is connected with the inlet of the high temperature side of the waste heat heater (8) and the outlet of the secondary steam (L) of the waste heat evaporation crystallizer (7) , 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 to the water collection pipe of the reused clean water (D), and the water collection pipe of the reused clean water (D) is connected to the desulfurization replenishment water (C ) imports are connected or not connected. 8. The waste heat evaporative desulfurization waste water zero discharge system according to claim 1, characterized in that the waste heat recovery unit (8, 9) includes a heat network return water waste heat heater (9), and the heat network return water waste heat The low-temperature side inlet of the heater (9) communicates with the heating network return water inlet and incoming water (N1), and the low-temperature side outlet of the heating network return water waste heat heater (9) communicates with the heating network return water inlet and outlet water (N2) , the high-temperature side inlet of the heat network return water waste heat heater (9) is connected with the outlet of the sewage secondary steam (L) of the waste heat evaporation crystallizer (7), and the high temperature side of the heat network return water waste heat heater (9) is second The outlet of the drainage (D2) is connected to the water collection pipe of the reused clean water (D), and the water collection pipe of the reused clean water (D) is connected to or not connected to the inlet of the desulfurization replenishment water (C). 9. The waste heat evaporative desulfurization waste water zero discharge system according to claim 1, characterized in that said salt separating device (6) adopts a nanofiltration membrane structure. 10. The waste heat evaporative desulfurization waste water zero discharge system according to claim 1, characterized in that the waste heat evaporation crystallizer (7) adopts a positive pressure one-stage heat exchange structure, a positive pressure multi-stage heat exchange structure, a negative pressure One-stage evaporative heat exchange structure or negative pressure multi-stage evaporative heat exchange structure.