Desulfurization wastewater treatment method and device

Abstract

The present disclosure provides a desulfurization wastewater treatment method and device, the method comprising: after obtaining the desulfurization wastewater to be treated, first heating the desulfurization wastewater to a first temperature under flash pressure, and then performing flash crystallization treatment on the desulfurization wastewater at the first temperature under high-temperature flue gas pressure. Thus, by heating the desulfurization wastewater to a first temperature under flash pressure, and performing flash crystallization treatment on the desulfurization wastewater at the first temperature based on the pressure difference between the flash pressure and the high-temperature flue gas pressure, the energy consumption in the desulfurization wastewater treatment process is reduced, and the efficiency of the desulfurization wastewater treatment is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of desulfurization wastewater discharge treatment, and particularly relates to a desulfurization wastewater treatment method and device. BACKGROUND

[0002] In the prior art, desulfurization wastewater can be treated by wet desulfurization, multi-effect evaporation crystallization and the like. However, the method for treating desulfurization wastewater has low treatment efficiency and high energy consumption. SUMMARY

[0003] The present disclosure aims to at least partially solve one of the technical problems in the related art.

[0004] A desulfurization wastewater treatment method is provided in the first aspect of the present disclosure, comprising:

[0005] obtaining desulfurization wastewater to be treated, wherein the desulfurization wastewater to be treated is obtained after pretreatment;

[0006] heating the desulfurization wastewater to a first temperature under flash evaporation pressure, wherein the first temperature is greater than the boiling point temperature of the desulfurization wastewater under high-temperature flue gas pressure, and the flash evaporation pressure is greater than the high-temperature flue gas pressure;

[0007] performing flash evaporation crystallization treatment on the desulfurization wastewater at the first temperature under the high-temperature flue gas pressure.

[0008] A desulfurization wastewater treatment device is provided in the second aspect of the present disclosure, comprising:

[0009] an obtaining module configured to obtain desulfurization wastewater to be treated, wherein the desulfurization wastewater to be treated is obtained after pretreatment;

[0010] a heating module configured to heat the desulfurization wastewater to a first temperature under flash evaporation pressure, wherein the first temperature is greater than the boiling point temperature of the desulfurization wastewater under high-temperature flue gas pressure, and the flash evaporation pressure is greater than the high-temperature flue gas pressure;

[0011] a flash evaporation crystallization module configured to perform flash evaporation crystallization treatment on the desulfurization wastewater at the first temperature under the high-temperature flue gas pressure.

[0012] A computer device is provided in the third aspect of the present disclosure, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the desulfurization wastewater treatment method provided in the first aspect of the present disclosure when executing the program.

[0013] The fourth aspect of the present disclosure provides a non-transitory computer-readable storage medium, which stores a computer program. The computer program is executed by a processor to implement the desulfurization wastewater treatment method according to the first aspect of the present disclosure.

[0014] The fifth aspect of the present disclosure provides a computer program product. When the instructions in the computer program product are executed by a processor, the desulfurization wastewater treatment method according to the first aspect of the present disclosure is performed.

[0015] The desulfurization wastewater treatment method and device provided by the present disclosure have the following beneficial effects:

[0016] In the embodiments of the present disclosure, after obtaining the desulfurization wastewater to be treated, the desulfurization wastewater is first heated to a first temperature under flash pressure, and then the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment under high-temperature flue gas pressure. Therefore, by heating the desulfurization wastewater to a first temperature under flash pressure, and based on the pressure difference between the flash pressure and the high-temperature flue gas pressure, the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment, thereby reducing the energy consumption in the desulfurization wastewater treatment process and improving the efficiency of the desulfurization wastewater treatment.

[0017] Additional aspects and advantages of the present disclosure will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and / or additional aspects and advantages of the present disclosure will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 is a flowchart of a desulfurization wastewater treatment method according to an embodiment of the present disclosure;

[0020] Figure 2 is a flowchart of a desulfurization wastewater treatment method according to another embodiment of the present disclosure;

[0021] Figure 3 is a flowchart of a desulfurization wastewater treatment method according to another embodiment of the present disclosure;

[0022] Figure 4 is a flowchart of a desulfurization wastewater treatment method according to another embodiment of the present disclosure;

[0023] Figure 5 is a structural diagram of a desulfurization wastewater treatment system according to an embodiment of the present disclosure;

[0024] Figure 6 is a structural diagram of a desulfurization wastewater treatment device according to an embodiment of the present disclosure;

[0025] Figure 7 A block diagram showing an exemplary computer device suitable for use in implementing embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0026] Embodiments of the present disclosure are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and characters throughout the figures denote the same or like components or elements having the same or similar functions. The embodiments described below are exemplary and are intended to be illustrative of the present disclosure and are not to be construed as limiting thereof. Conversely, the embodiments of the present disclosure encompass all changes, modifications and alterations of the concepts disclosed and described herein, falling within the true spirit and scope of the appended claims.

[0027] Figure 1 is a flowchart of a desulfurization wastewater treatment method according to an embodiment of the present disclosure.

[0028] As shown in Figure 1 , the desulfurization wastewater treatment method comprises:

[0029] Step 101, obtaining desulfurization wastewater to be treated, wherein the desulfurization wastewater to be treated is obtained after pretreatment.

[0030] In the present disclosure, before obtaining the desulfurization wastewater to be treated, the desulfurization wastewater can be first pretreated. The desulfurization wastewater after wet flue gas desulfurization is subjected to aeration treatment to uniformly and stably control the water quality, so that the subsequent equipment runs stably. Then, the desulfurization wastewater is fully reacted with a chemical reagent to remove heavy metal ions such as Pb 3+ , Fe 3+ , Cr 3+ , Cd 2+ , Hg 2+ , Cu 2+ , etc. in the desulfurization wastewater to generate corresponding hydroxides and sulfides precipitates, soften the desulfurization wastewater, and alleviate the problems of fouling and plugging of the subsequent equipment during operation. After that, the desulfurization wastewater is subjected to sedimentation and clarification to remove suspended solids, heavy metals, precipitates and other impurities in the desulfurization wastewater. The pH value of the desulfurization wastewater is adjusted. Finally, the desulfurization wastewater is subjected to multi-medium filtration and concentration to remove impurities and reduce the pollution index of the desulfurization wastewater, and to achieve the reduction of the desulfurization wastewater, thereby effectively reducing the cost of desulfurization wastewater treatment.

[0031] It should be noted that the desulfurization wastewater can be chemically reacted with Na2SO4 solution, NaOH solution, etc. to reduce the treatment cost, which is not limited in the present disclosure.

[0032] It should be noted that the desulfurization wastewater after the multi-medium filter can be concentrated by the desulfurization wastewater concentration system, so as to realize the reduction of the desulfurization wastewater and save the cost. The desulfurization wastewater concentration system can include any membrane device, such as a special channel reverse osmosis (SCRO) membrane device, a disk tube reverse osmosis (DIRO) membrane device, and a membrane distillation (MD) device. For example, the wastewater concentration system can increase the concentration of the desulfurization wastewater to 60 g / L by the SCRO membrane device, then increase the concentration of the desulfurization wastewater to 120 g / L by the DTRO membrane device, and finally increase the concentration of the desulfurization wastewater to more than 200 g / L by the MD membrane device, so as to effectively reduce the evaporation treatment load and save the cost, which is not limited in the present disclosure.

[0033] In step 102, the desulfurization wastewater is heated to a first temperature under a flash pressure, wherein the first temperature is greater than the boiling point temperature of the desulfurization wastewater under a high-temperature flue gas pressure, and wherein the flash pressure is greater than the high-temperature flue gas pressure.

[0034] The flash pressure is the pressure of the desulfurization wastewater when the desulfurization wastewater is subjected to flash treatment.

[0035] In the present disclosure, after obtaining the desulfurization wastewater to be treated, the pressure of the desulfurization wastewater can be first increased to the flash pressure, and then the desulfurization wastewater is heated to the first temperature under the flash pressure.

[0036] It should be noted that the boiling point temperature of the desulfurization wastewater to be treated under the high-temperature flue gas pressure is different, which is not limited in the present disclosure.

[0037] It should be noted that the high-temperature flue gas in different places using different boilers can have different corresponding high-temperature flue gas pressures. For example, the high-temperature flue gas after the reheater in the natural circulation boiler can have a different corresponding high-temperature flue gas pressure than the high-temperature flue gas in other places of the natural circulation boiler, which is not limited in the present disclosure.

[0038] It should be noted that the high-temperature flue gas after heating the desulfurization wastewater can be sent to the boiler tail flue to continue participating in the flue gas treatment process, realizing the secondary utilization of the high-temperature flue gas.

[0039] In step 103, the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment under the high-temperature flue gas pressure.

[0040] In the present disclosure, after the desulfurization wastewater is heated to the first temperature under the flash pressure, the desulfurization wastewater at the first temperature can be subjected to the first-stage flash crystallization treatment through the desulfurization wastewater flash evaporator.

[0041] It should be noted that the heat source used in the flash evaporator is high-temperature flue gas, at this time, the pressure in the flash evaporator is the pressure of the high-temperature flue gas. After the desulfurization wastewater under the flash pressure is introduced into the flash evaporator, since the flash pressure is greater than the pressure of the high-temperature flue gas, the desulfurization wastewater is in a superheated state and can be immediately evaporated.

[0042] It should be noted that since the surface tension and viscosity of water gradually decrease with the increase of water temperature, when the desulfurization wastewater is heated to the first temperature, the corresponding surface tension and viscosity of water are lower than the corresponding surface tension and viscosity of the desulfurization wastewater at normal temperature, and under the same conditions, the particle size of the desulfurization wastewater at a higher temperature is smaller than that of the desulfurization wastewater at normal temperature, and the desulfurization wastewater at a higher temperature is more easily evaporated, thereby accelerating the evaporation of the desulfurization wastewater.

[0043] In the present disclosure, when the desulfurization wastewater at the first temperature is subjected to the flash crystallization treatment under the pressure of the high-temperature flue gas, the concentrated salt slurry formed after the desulfurization wastewater is treated by the desulfurization wastewater flash evaporator can be subjected to solid-liquid separation to obtain solid crystalline salt, and the flash steam generated after the desulfurization wastewater is treated by the desulfurization wastewater flash evaporator can be condensed to form condensed water, which is recovered for use as boiler makeup water to make up for the water vapor loss of the thermal system, and then the separated desulfurization wastewater mother liquor is introduced into the desulfurization wastewater flash evaporator for evaporation again, thereby realizing the reuse of the desulfurization wastewater and the zero-emission treatment of the desulfurization wastewater.

[0044] In addition, the high-temperature flue gas of the boiler is used as the heat source in the desulfurization wastewater flash evaporator, which can effectively utilize the heat of the flue gas, avoid waste of heat energy, reduce energy consumption, and thereby save costs.

[0045] In the present disclosure, after the desulfurization wastewater to be treated is obtained, the desulfurization wastewater is first heated to the first temperature under the flash pressure, and then the desulfurization wastewater at the first temperature is subjected to the flash crystallization treatment under the pressure of the high-temperature flue gas. In this way, by heating the desulfurization wastewater to the first temperature under the flash pressure, the desulfurization wastewater at the first temperature is subjected to the flash crystallization treatment based on the pressure difference between the flash pressure and the pressure of the high-temperature flue gas, thereby reducing the energy consumption in the desulfurization wastewater treatment process and improving the efficiency of the desulfurization wastewater treatment.

[0046] Figure 2 is a flowchart of the desulfurization wastewater treatment method according to another embodiment of the present disclosure.

[0047] As shown in Figure 2 , the desulfurization wastewater treatment method comprises:

[0048] In step 201, the desulfurization wastewater to be treated is obtained, wherein the desulfurization wastewater to be treated is obtained after pretreatment.

[0049] The specific implementation form of step 201 can refer to the detailed description of other embodiments of the present disclosure, which will not be repeated here.

[0050] In step 202, the desulfurization wastewater is heated to a first temperature by using the boiler wastewater under the flash pressure.

[0051] The boiler wastewater can be the boiler water discharged by the boiler. For example, the boiler wastewater can be the boiler water with high salt section water concentration discharged by the continuous blowdown pipe of the natural circulation boiler, and the present disclosure does not make any limitation in this regard.

[0052] In the present disclosure, when the desulfurization wastewater is heated to a first temperature by using the boiler wastewater under the flash pressure, the high-temperature and high-pressure wastewater containing impurities generated by the boiler wastewater expander can be used as a heat source to heat the desulfurization wastewater first, and then the high-temperature steam generated by the boiler wastewater expander can be used as a heat source to heat the desulfurization wastewater to the first temperature for the second time, thereby realizing the recycling of the waste heat of the boiler wastewater and reducing energy waste.

[0053] It should be noted that the high-temperature and high-pressure wastewater containing impurities after heating the desulfurization wastewater can be purified and filtered to obtain clean heat medium water, realizing recycling.

[0054] It should be noted that the high-temperature steam after heating the desulfurization wastewater can be sent to the deaerator for recycling.

[0055] In step 203, the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment under the high-temperature flue gas pressure.

[0056] The specific implementation form of step 203 can refer to the detailed description of other embodiments of the present disclosure, which will not be repeated here.

[0057] In the embodiments of the present disclosure, after obtaining the desulfurization wastewater to be treated, the desulfurization wastewater is first heated to a first temperature by using the boiler wastewater under the flash pressure, and then the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment under the high-temperature flue gas pressure. Thus, by heating the desulfurization wastewater by using the boiler wastewater under the flash pressure and subjecting the heated desulfurization wastewater to flash crystallization under the high-temperature flue gas pressure, the recycling of the waste heat of the boiler wastewater is realized, the energy waste is reduced, and the efficiency of the desulfurization wastewater treatment is improved.

[0058] Figure 3 is a flow diagram of a desulfurization wastewater treatment method according to another embodiment of the present disclosure.

[0059] As Figure 3 shown in the figure, the desulfurization wastewater treatment method comprises the following steps:

[0060] In step 301, the desulfurization wastewater to be treated is obtained, wherein the desulfurization wastewater to be treated is obtained after pretreatment.

[0061] The specific implementation form of step 301 can refer to the detailed description of other embodiments of the present disclosure, which will not be described here.

[0062] In step 302, it is determined whether the boiler water level reaches a water level threshold.

[0063] The water level threshold is a critical value of the boiler water level for determining whether the boiler water level is normal, which can be pre-set, and the present disclosure does not limit it.

[0064] It should be noted that when the operating state of the boiler is abnormal, such as boiler shutdown, pipe explosion, low fluorine operation, etc., the boiler water level may be in an abnormally high state, which is not limited by the present disclosure.

[0065] It should be noted that the water level threshold corresponding to different boilers may be the same or may not be the same, which is not limited by the present disclosure.

[0066] In some possible implementation forms, when it is determined that the boiler water level does not reach the water level threshold, it can be considered that the current boiler water level is in a normal state, and the boiler is running normally. At this time, the desulfurization wastewater can be heated to a first temperature by the boiler wastewater under the flash pressure, which is not limited by the present disclosure.

[0067] In some possible implementation forms, when it is determined that the boiler water level reaches the water level threshold, it can be considered that the current boiler water level is in an abnormal state, and the boiler may have problems. At this time, the desulfurization wastewater cannot be heated by the boiler wastewater.

[0068] In step 303, the pressure of the boiler wastewater expansion tank is adjusted when the boiler water level reaches the water level threshold, until the boiler water level is less than the water level threshold.

[0069] In the present disclosure, when the boiler water level reaches the water level threshold, the pressure in the boiler wastewater expansion tank can be adjusted to ensure that the expansion tank does not overpressure.

[0070] In some possible implementation forms, when the boiler water level reaches the water level threshold, the pressure in the heat exchanger can also be adjusted to ensure that the heat exchanger does not overpressure and ensure system safety.

[0071] In the present disclosure, in the case that the boiler water level reaches the water level threshold, the pressure of the boiler wastewater expansion tank is first adjusted, then the problem causing the boiler water level to reach the water level threshold is found and repaired, and until the boiler water level is less than the water level threshold, it can be considered that the current boiler water level is in a normal state, at this time, the desulfurization wastewater can be heated by the boiler wastewater.

[0072] Step 304, heating the desulfurization wastewater to a first temperature under a flash pressure, wherein the first temperature is greater than the boiling point temperature of the desulfurization wastewater under the high-temperature flue gas pressure, and wherein the flash pressure is greater than the high-temperature flue gas pressure.

[0073] Step 305, performing flash crystallization treatment on the desulfurization wastewater at a first temperature under a high-temperature flue gas pressure.

[0074] The specific implementation forms of steps 304 to 305 can be referred to the detailed description of other embodiments of the present disclosure, which will not be repeated here.

[0075] In the embodiments of the present disclosure, after obtaining the desulfurization wastewater to be processed, it is first determined whether the boiler water level reaches the water level threshold, in the case that the boiler water level reaches the water level threshold, the pressure of the boiler wastewater expansion tank is adjusted, until the boiler water level is less than the water level threshold, then the desulfurization wastewater is heated to a first temperature under a flash pressure, and finally the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment under a high-temperature flue gas pressure. Thus, in the case that the boiler water level reaches the water level threshold, the pressure of the boiler wastewater expansion tank is adjusted until the boiler water level is less than the water level threshold, under the flash pressure, the desulfurization wastewater is heated by the boiler wastewater, and under the high-temperature flue gas pressure, the heated boiler wastewater is subjected to flash crystallization, thereby improving the efficiency of the desulfurization wastewater while ensuring the safety and reliability of the desulfurization wastewater treatment.

[0076] Figure 4 is a flowchart of a desulfurization wastewater treatment method according to another embodiment of the present disclosure.

[0077] As shown in Figure 4 , the desulfurization wastewater treatment method comprises:

[0078] Step 401, obtaining desulfurization wastewater to be processed, wherein the desulfurization wastewater to be processed is obtained after pretreatment.

[0079] Step 402, determining whether the boiler water level reaches the water level threshold.

[0080] The specific implementation forms of steps 401 to 402 can be referred to the detailed description of other embodiments of the present disclosure, which will not be repeated here.

[0081] In step 403, the opening and closing states of the first valve and the second valve are adjusted by the DCS system until the boiler water level is less than the water level threshold under certain conditions.

[0082] The first valve is an electric door for controlling the pressure of the boiler wastewater expansion tank to be directly discharged to the atmosphere, and the second valve is an electric door for controlling the boiler wastewater waste heat recovery.

[0083] The DCS is an abbreviation of Distributed Control System.

[0084] In some possible implementation forms, the certain conditions can include at least one of the following: the boiler water level reaches the water level threshold; the emergency drain electric door of the boiler drum is opened; and the pressure of the boiler wastewater expansion tank reaches the pressure threshold, which is not limited in the present disclosure.

[0085] The pressure threshold is a critical pressure value that the boiler wastewater expansion tank can withstand, which can be pre-set, and is not limited in the present disclosure.

[0086] It should be noted that the performance and design of the boiler wastewater expansion tank are different, and the corresponding pressure threshold can be different or can be the same, which is not limited in the present disclosure.

[0087] In the present disclosure, when the boiler water level reaches the water level threshold, the emergency drain electric door of the boiler drum will be opened, and the opening signal of the emergency drain electric door can be fed back to the first valve by the DCS system to achieve synchronous opening, so as to ensure that the boiler wastewater expansion tank does not overpressure. After receiving the opening signal, the first valve can send a closing signal to the second valve through the DCS system, so that the second valve is automatically closed, to ensure that the heat exchanger does not overpressure, thereby ensuring the safety of the system.

[0088] In some possible implementation forms, in the DCS system, when the boiler water level reaches the water level threshold, the DCS system can send the current water level value of the boiler water level to the first valve as a signal, so that the first valve performs the opening operation; or when the emergency drain electric door of the boiler drum is opened, the DCS system can send the opening operation of the emergency drain electric door to the first valve as a signal, so that the first valve performs the opening operation; or when the pressure of the boiler wastewater expansion tank reaches the pressure threshold, the DCS system can send the current pressure value of the expansion tank to the first valve as a signal, so that the first valve performs the opening operation.

[0089] It should be noted that when the boiler water level reaches the water level threshold, the DCS system can also send the current water level value of the boiler water level to the emergency drain electric door as an action value of the emergency drain electric door to open the emergency drain electric door. The emergency drain electric door can determine the opening instruction action value of the first valve according to the action value, for example, the DCS system can determine 95% of the action value of the emergency drain electric door as the opening instruction action value of the first valve, and the like, which is not limited in the present disclosure.

[0090] It should be noted that when the pressure of the boiler wastewater expansion tank reaches the pressure threshold, the DCS system can also determine the opening instruction value of the first valve according to the current pressure value of the expansion tank, for example, the DCS system can determine 98% of the current pressure value of the expansion tank as the opening instruction value of the first valve, and the like, which is not limited in the present disclosure.

[0091] In the present disclosure, the first valve receives any one of the boiler water level value signal sent by the DCS system, the opening action signal of the emergency drain electric door, and the pressure value signal of the expansion tank, and can perform the opening action to adjust the pressure of the expansion tank, which is not limited in the present disclosure.

[0092] It should be noted that when the first valve fails to open, the DCS system can feed back the signal of the failure of the first valve to the third valve, wherein the third valve is an electric door for controlling the bypass pipeline of the boiler wastewater expansion tank to directly discharge the atmosphere, so that the third valve performs the opening action to ensure system safety, and the opening action signal of the third valve is fed back to the first valve through the DCS system, which is not limited in the present disclosure.

[0093] In the present disclosure, in the case where the first valve does not receive any one of the boiler water level value signal sent by the DCS system, the opening action signal of the emergency drain electric door, and the pressure value signal of the expansion tank, the DCS system can control the first valve to be in a closed state, and at the same time, the second valve is opened to recover the waste heat of the boiler wastewater, which is not limited in the present disclosure.

[0094] In the present disclosure, in the case where the boiler water level reaches the water level threshold, it can be considered that the boiler water level is in an abnormal state, at this time, the DCS system can be controlled to open the first valve, close the second valve, cut off the connection between the expansion tank and the boiler drum, check the cause of the abnormal boiler water level and repair it, and then restore the connection between the expansion tank and the drum again to heat the desulfurization wastewater, which is not limited in the present disclosure.

[0095] Step 404, heating the desulfurization wastewater to a first temperature under a flash pressure, wherein the first temperature is greater than the boiling point temperature of the desulfurization wastewater under the high-temperature flue gas pressure, and the flash pressure is greater than the high-temperature flue gas pressure.

[0096] Step 405, under high-temperature flue gas pressure, the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment.

[0097] The specific implementation forms of steps 404 to 405 can refer to the detailed description of other embodiments of the present disclosure, which will not be repeated here.

[0098] In the embodiments of the present disclosure, after obtaining the desulfurization wastewater to be treated, it is first determined whether the boiler water level reaches the water level threshold. Under certain conditions, the opening and closing states of the first valve and the second valve are adjusted by the distributed control system (DCS) system until the boiler water level is less than the water level threshold. Then, under the flash pressure, the desulfurization wastewater is heated to the first temperature, and finally, under the high-temperature flue gas pressure, the desulfurization wastewater at the first temperature is subjected to flash crystallization treatment. Thus, in the case of abnormal boiler water level, the valve of the expansion vessel is adjusted by the DCS system to adjust the pressure of the expansion vessel until the boiler water level returns to normal. Under the flash pressure, the desulfurization wastewater is heated, and under the high-temperature flue gas pressure, the heated desulfurization wastewater is subjected to flash crystallization. Therefore, the safety and reliability of the desulfurization wastewater treatment are ensured, and the efficiency of the desulfurization wastewater treatment is improved.

[0099] The following will be described in combination with Figure 5 The flow of the desulfurization wastewater treatment method provided by the embodiments of the present disclosure will be described, Figure 5 is a structural schematic diagram of the desulfurization wastewater treatment system proposed by the embodiments of the present disclosure.

[0100] As Figure 5 shown, the devices included therein are as follows: 1-steam drum; 2-fixed expansion vessel; 3-desalted water tank; 4-filtration and cleaning device; 5-emergency water discharge electric door; 6-third valve; 7-first valve; 8-second valve; 9-boiler; 10-air preheater; 11-oxygen remover; 12-feedwater pump; 13-high-pressure heater; 14-first desulfurization wastewater preheater; 15-second desulfurization wastewater preheater; 16-wastewater pump; 17-desulfurization wastewater flash evaporator; 18-solid-liquid centrifugal device; 19-aeration tank; 20-reaction tank; 21-sedimentation tank; 22-settling tank; 23-regulating tank; 24-sludge thickening tank; 25-plate-and-frame filter press; 26-multi-media filter; 27-wastewater concentration system; 28-pressurizing system; 29-deaerator; 30-condenser; 31-reuse water tank; and 32-economizer.

[0101] Firstly, the desulfurization wastewater after wet flue gas desulfurization passes through the aeration tank 19, the reaction tank 20, the sedimentation tank 21, the clarifier 22 in turn to remove heavy metals, suspended solids, precipitates and other impurities in the desulfurization wastewater, and then passes through the adjusting tank 23 to adjust the pH of the desulfurization wastewater, and then passes through the multi-medium filter 26 and the wastewater concentration system 27 in turn to remove small suspended solids, bacteria, high molecular organic matter and fine particulate matter and other impurities in the desulfurization wastewater, and concentrate the desulfurization wastewater to achieve reduction. In addition, the sludge containing heavy metal elements, other insoluble precipitates and suspended solids generated in the reaction tank 20, the sedimentation tank 21 and the clarifier 22 can be transported to the sludge concentration tank 24 through the sludge discharge pipeline, and then the sludge in the sludge concentration tank 24 is sent to the plate and frame filter press 25 for pressure filtration and then discharged.

[0102] Then the pressure of the desulfurization wastewater after the wastewater concentration system 27 treatment can be pressurized to the flash pressure by the pressurizing system 28, and the high-temperature flue gas after the reheater of the boiler 9 is less than the flash pressure; the desulfurization wastewater after the pressurizing system 28 treatment passes through the first desulfurization wastewater preheater 14 and the second desulfurization wastewater preheater 15 in turn to heat the desulfurization wastewater by using the blowdown water and steam generated in the constant volume expander 2 as a heat source, so that the temperature of the desulfurization wastewater is higher than the boiling point temperature of the desulfurization wastewater under the pressure of the high-temperature flue gas introduced in the flue, and then the non-condensable gas and volatile components in the desulfurization wastewater are removed by the degassing machine 29, and then the desulfurization wastewater is transported to the desulfurization wastewater flash evaporator 17 for flash evaporation and crystallization by the wastewater pump 16.

[0103] The concentrated salt slurry formed after the desulfurization wastewater is treated by the desulfurization wastewater flash evaporator 17 enters the solid-liquid centrifugal device 18 for solid-liquid separation, and the solid crystalline salt is obtained after being treated by the centrifuge and the dryer, and the separated wastewater mother liquor can be introduced into the desulfurization wastewater flash evaporator 17 for evaporation again. The flash steam generated after the desulfurization wastewater is treated by the desulfurization wastewater flash evaporator 17 is sent to the condenser 30, and the condensed water formed by condensation enters the reuse water tank 31, which can be recycled to supplement the water vapor loss of the thermal system to supplement the boiler feed water, so as to realize the reuse of the desulfurization wastewater and the zero discharge treatment system of the desulfurization wastewater. The heat source used by the desulfurization wastewater flash evaporator 17 is the high-temperature flue gas after the reheater of the boiler 9, and the heat-exchanged high-temperature flue gas is sent to the air preheater 10 for secondary utilization.

[0104] Wherein, when the blowdown water and steam generated by the constant-discharge expansion vessel 2 are used as heat sources to heat the desulfurization wastewater through the first desulfurization wastewater preheater 14 and the second desulfurization wastewater preheater 15 under the flash pressure, the hot feed water from the economizer 32 of the boiler 9 enters the steam drum 1 first, the high-temperature and high-pressure wastewater containing impurities in the steam drum 1 enters the constant-discharge expansion vessel 2 for expansion through the emergency blow-off motor door 5, the expanded high-temperature wastewater enters the first desulfurization wastewater preheater 14 through the water outlet of the constant-discharge expansion vessel 2 and the hot water inlet of the first desulfurization wastewater preheater 14 as a heat source for preheating the desulfurization wastewater, the high-temperature wastewater containing impurities after heating the desulfurization wastewater is discharged into the filtering and cleaning device 4 through the outlet filter screen, and the clean heat medium water after heating the desulfurization wastewater enters the desalted water tank 3 for recycling; the high-temperature steam generated after the expansion of the constant-discharge expansion vessel 2 enters the steam inlet of the second desulfurization wastewater preheater 15 through the boiler wastewater waste heat utilization steam main pipeline provided with the second valve 8 above the constant-discharge expansion vessel 2, the high-temperature steam is used as a heat source to exchange heat with the desulfurization wastewater heated by the first desulfurization wastewater preheater 14 in the second desulfurization wastewater preheater 15, and the low-temperature steam after heat exchange flows out from the steam outlet of the second desulfurization wastewater preheater 15 and enters the deaerator 11 through a pipeline for recycling. Wherein, the third valve 6 is a bypass pipeline motor door for controlling the pressure of the expansion vessel to be directly discharged into the atmosphere; the first valve 7 is a constant-discharge expansion vessel directly discharged into the atmosphere motor door; and the second valve 8 is a boiler wastewater waste heat online recycling motor door.

[0105] Figure 6 FIG. 1 is a structural schematic diagram of a desulfurization wastewater treatment device according to an embodiment of the present disclosure.

[0106] As shown in FIG. 1, the desulfurization wastewater treatment device 600 includes an obtaining module 601, a heating module 602, and a flash crystallization module 603. Figure 6 The obtaining module 601 is configured to obtain desulfurization wastewater to be treated, wherein the desulfurization wastewater to be treated is obtained after pretreatment.

[0107] The heating module 602 is configured to heat the desulfurization wastewater to a first temperature under a flash pressure, wherein the first temperature is greater than a boiling point temperature of the desulfurization wastewater under a high-temperature flue gas pressure, and the flash pressure is greater than the high-temperature flue gas pressure.

[0108] The flash crystallization module 603 is configured to perform flash crystallization treatment on the desulfurization wastewater at the first temperature under the high-temperature flue gas pressure.

[0109] Optionally, the heating module 602 is specifically configured to:

[0110] heat the desulfurization wastewater to the first temperature by using boiler wastewater.

[0111]

[0112] ​Optionally, before heating the desulfurization wastewater to the first temperature, further comprising:

[0113] A determination module (not shown in the figure) is configured to determine whether the boiler water level reaches a water level threshold.

[0114] An adjustment module (not shown in the figure) is configured to adjust the pressure of the boiler wastewater expansion tank until the boiler water level is less than the water level threshold, if the boiler water level reaches the water level threshold.

[0115] Optionally, the adjustment module (not shown in the figure) is specifically configured to:

[0116] Under certain conditions, the DCS system controls the opening and closing states of the first valve and the second valve, wherein the first valve is an electric door for controlling the pressure of the boiler wastewater expansion tank to be directly discharged to the atmosphere, and the second valve is an electric door for controlling the waste heat recovery of the boiler wastewater.

[0117] Optionally, the certain conditions include at least one of the following:

[0118] The boiler water level reaches the water level threshold;

[0119] The emergency drain electric door of the boiler drum is opened;

[0120] The pressure of the boiler wastewater expansion tank reaches a pressure threshold.

[0121] The functions and specific implementation principles of the above modules in the embodiments of the present disclosure can be referred to the above method embodiments, which will not be described here.

[0122] The desulfurization wastewater treatment device in the embodiments of the present disclosure, after obtaining the desulfurization wastewater to be treated, first heats the desulfurization wastewater to a first temperature under flash pressure, and then performs flash crystallization treatment on the desulfurization wastewater at the first temperature under high-temperature flue gas pressure. Therefore, by heating the desulfurization wastewater to the first temperature under the flash pressure, the desulfurization wastewater at the first temperature is treated by flash crystallization based on the pressure difference between the flash pressure and the high-temperature flue gas pressure, thereby reducing the energy consumption in the desulfurization wastewater treatment process and improving the efficiency of the desulfurization wastewater treatment.

[0123] Figure 7 A block diagram of an exemplary computer device suitable for implementing the embodiments of the present disclosure is shown. Figure 7 The displayed computer device 12 is only an example and should not impose any limitation on the functions and use range of the embodiments of the present disclosure.

[0124] As Figure 7As shown, the computer device 12 is in the form of a general-purpose computing device. The components of the computer device 12 can include, but are not limited to, one or more processors or processing units 16, a system memory 28, and a bus 18 that couples various system components including the system memory 28 to the processing unit 16.

[0125] The bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration bus, a processor or local bus using any of a variety of bus architectures including Industry Standard Architecture (ISA), Micro Channel Architecture (MCA), Enhanced ISA (EISA), Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

[0126] The computer device 12 typically includes a variety of computer system readable media. Such media can be any available media that is located either in or out of the computer device 12, such as volatile and non-volatile media, removable and non-removable media.

[0127] The memory 28 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The computer device 12 can further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, a storage system 34 can be used for reading from and writing to non-removable, non-volatile magnetic media (e.g., a "hard drive"). Figure 7 A removable / non-removable volatile, non-volatile computer system storage medium (e.g., a floppy disk, a magnetic tape, and / or an optical disk, etc.) is typically used for storing data that is either loaded into the computer device 12 or is to be loaded into the computer device 12.

[0128] Although Figure 7A disk drive, a floppy disk drive, a CD-ROM drive, a DVD-ROM drive, or other removable media drive, can be provided, as shown in FIG. 1, for reading from and writing to a removable n on-volatile magnetic media (e.g., a "floppy disk"), and to a removable non-volatile optical disk (e.g., a CD-ROM, a DVD-ROM, or other optical media). In such cases, each will include a drive mechanism which will interface with the bus 18 through one or more data media interfaces. The memory 28 can include, for example, one or more program products being used by the processing unit 16, for example, one or more program modules 42, being executed by the processing unit 16, used in conduction of the subject embodiments.

[0129] The program / utility, having a set (at least one) of program modules 42, can be stored in memory 28 by way of example, and not limitation, as well as an operating system, one or more application programs, other program modules, and program data, each or some combination thereof, can include implementation of the network environment. The program modules 42 generally carry out the functions and / or methodologies of the subject embodiments as described herein.

[0130] The computer device 12 can also communicate with one or more external devices 14 such as a keyboard, a pointing device, a display 24, etc.; one or more devices that enable a human user to interact with the computer device 12; and / or one or more devices that enable the computer device 12 to communicate with one or more other computer devices. Such communication can be via the input / output (I / O) interface(s) 22. Further, the computer device 12 can communicate with one or more networks (such as a Local Area Network (LAN), a Wide Area Network (WAN), and / or the public network such as the Internet) through a network adapter 20. As shown, the network adapter 20 communicates with the other components of the computer device 12 through the bus 18. It should be appreciated that, although not shown, other hardware and / or software components could be used in conjunction with the computer device 12. These include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc.

[0131] The processing unit 16 performs various functions and data processing by running programs stored in the system memory 28, such as implementing the desulfurization wastewater treatment method mentioned in the foregoing embodiments.

[0132] To achieve the above-mentioned embodiments, the present disclosure further provides a non-transitory computer-readable storage medium having stored thereon a computer program, which, when executed by a processor, implements the desulfurization wastewater treatment method as proposed in the foregoing embodiments of the present disclosure.

[0133] To achieve the above-mentioned embodiments, the present disclosure further provides a computer program product, which, when instructions in the computer program product are executed by a processor, executes the desulfurization wastewater treatment method as proposed in the foregoing embodiments of the present disclosure.

[0134] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure following, in general, the principles of the present disclosure and including such features that are evident to those skilled in the art to which the present disclosure pertains. The specification and examples are to be considered exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

[0135] It should be understood that the present disclosure is not limited to the precise structures as herein described and illustrated in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the claims that follow.

[0136] It should be noted that in the description of the present disclosure, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance. In addition, in the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0137] Any process or method descriptions or descriptions of the flow diagrams in the present disclosure can be understood as representing code modules, segments, or portions of code that include one or more executable instructions for performing specific logical functions or steps in the process, and the various embodiments of the present disclosure include additional implementations that can not be described in detail in the description of the flow diagrams and / or descriptions of the processes. It should be understood that the flow diagrams and / or descriptions of the processes can be implemented in software, hardware, or a combination thereof. In the case of software, the code can be executed by a processor, and the results of the execution can be output to an associated device. In the case of hardware, the code can be implemented in the form of a hardware logic block, which can be implemented in a single integrated circuit, or in multiple integrated circuits.

[0138] It should be understood that portions of the present disclosure can be realized with hardware, software, firmware or a combination thereof. In the above embodiments, a plurality of steps or methods can be realized with software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if realized with hardware, and as in another embodiment, any one or a combination of the following technologies known in the art can be used: discrete logic circuitry having logic gates for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

[0139] Those skilled in the art of the present technology can understand that all or part of the steps carried out by the above-mentioned embodiment methods can be completed by programs instructing related hardware, and the programs can be stored in a computer readable storage medium, and when executed, include one or a combination of steps of the method embodiments.

[0140] In addition, each functional unit in each embodiment of the present disclosure can be integrated into one processing module, or each unit can be physically present alone, or two or more units can be integrated into one module. The above-mentioned integrated module can be realized in the form of hardware or in the form of a software function module. The integrated module, if realized in the form of a software function module and sold or used as an independent product, can also be stored in a computer readable storage medium.

[0141] The above-mentioned storage medium can be a read-only memory, a magnetic disk or an optical disk, etc.

[0142] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0143] Although the embodiments of the present disclosure have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the present disclosure, and those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the present disclosure.

Claims

1. A desulfurization wastewater treatment method characterized by, The method comprises: First, the desulfurization wastewater after wet flue gas desulfurization passes through the aeration tank 19, the reaction tank 20, the sedimentation tank 21, and the clarifier 22 in sequence to remove heavy metals, suspended solids, and precipitates in the desulfurization wastewater, and then passes through the conditioning tank 23 to adjust the pH of the desulfurization wastewater, and then passes through the multi-medium filter 26 and the wastewater concentration system 27 in sequence to remove small suspended solids, bacteria, high-molecular organic matter, and fine particulate matter in the desulfurization wastewater, and concentrate the desulfurization wastewater to achieve reduction. In addition, the heavy metal-containing precipitates, other insoluble precipitates, and suspended solids generated by the reaction tank 20, the sedimentation tank 21, and the clarifier 22 are transported to the sludge concentration tank 24 through the sludge discharge pipeline; Then, the pressure of the desulfurization wastewater treated by the wastewater concentration system 27 is increased to the flash pressure by the pressurization system 28, and the high-temperature flue gas after the reheater of the boiler 9 has a pressure lower than the flash pressure. The desulfurization wastewater treated by the pressurization system 28 passes through the first desulfurization wastewater preheater 14 and the second desulfurization wastewater preheater 15 in sequence to heat the desulfurization wastewater using the blowdown water and steam generated by the constant-volume expander 2 as a heat source, so that the temperature of the desulfurization wastewater is higher than the boiling point temperature of the desulfurization wastewater under the pressure of the high-temperature flue gas introduced into the flue. Then, the desulfurization wastewater is treated by the degassing machine 29 to remove non-condensable gases and volatile components, and then is transported to the desulfurization wastewater flash evaporator 17 by the wastewater pump 16 for flash evaporation and crystallization; The concentrated salt slurry formed after the desulfurization wastewater is treated by the desulfurization wastewater flash evaporator 17 enters the solid-liquid centrifugal device 18 for solid-liquid separation, and the solid crystalline salt is obtained after being treated by the centrifugal machine and the drying machine. The separated wastewater mother liquor is introduced into the desulfurization wastewater flash evaporator 17 for evaporation again. The flash steam generated after the desulfurization wastewater is treated by the desulfurization wastewater flash evaporator 17 is sent to the condenser 30, and the condensed water formed by condensation enters the reuse water tank 31. The water vapor loss of the thermal system can be recovered to supplement the boiler feed water, realizing the reuse and zero-emission treatment of the desulfurization wastewater. The heat source used by the desulfurization wastewater flash evaporator 17 is the high-temperature flue gas after the reheater of the boiler 9. The high-temperature flue gas after heat exchange is sent to the air preheater 10 for secondary utilization. Wherein, in the flash pressure, by the first desulfurization wastewater preheater 14 and the second desulfurization wastewater preheater 15, the blowdown water and steam generated by the constant discharge expansion vessel 2 are used as heat source to heat the desulfurization wastewater, first, the hot feed water from the economizer 32 of the boiler 9 enters the steam drum 1, the high-temperature high-pressure wastewater containing impurities in the steam drum 1 enters the constant discharge expansion vessel 2 through the emergency drain electric door 5, the expanded high-temperature wastewater enters the first desulfurization wastewater preheater 14 through the water outlet of the constant discharge expansion vessel 2 and the hot water inlet of the first desulfurization wastewater preheater 14 as the heat source of the preheated desulfurization wastewater, the high-temperature wastewater containing impurities after heating the desulfurization wastewater is discharged into the filtering and cleaning device 4 through the outlet filter screen, and the clean heat medium water after heating the desulfurization wastewater enters the desalted water tank 3 for recycling; The high-temperature steam generated after the expansion of the constant discharge expansion vessel 2 enters the steam inlet of the second desulfurization wastewater preheater 15 through the boiler wastewater waste heat utilization steam main pipeline provided with the second valve 8 above the constant discharge expansion vessel 2, the high-temperature steam is used as heat source to exchange heat with the desulfurization wastewater heated by the first desulfurization wastewater preheater 14 in the second desulfurization wastewater preheater 15, and the low-temperature steam after heat exchange flows out from the steam outlet of the second desulfurization wastewater preheater 15 and enters the deaerator 11 through the pipeline for recycling.

2. The method of claim 1, wherein, The sludge in the sludge concentration tank 24 is sent to the plate and frame filter press 25 for pressure filtration and then discharged.

3. The method of claim 1, wherein, The third valve 6 is a bypass pipeline electric door for controlling the pressure of the constant discharge expansion vessel 2 to directly discharge to the atmosphere; The second valve 8 is a boiler wastewater waste heat online recycling electric door.

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