Boiler system capable of treating desulfurization wastewater

Abstract

A boiler system capable of treating desulfurization wastewater is characterized by comprising a boiler, a wastewater inlet header pipe, a steam inlet header pipe and at least one wastewater-soot blower, a hearth of a combustion space is arranged in the middle of the boiler; desulfurization waste water is led to the waste water-soot blowing device through a waste water inlet header pipe and is converged with steam led in through a steam inlet header pipe in the waste water-soot blowing device, and the desulfurization waste water is sprayed into a hearth of a boiler along with the steam after being heated by the steam in the waste water-soot blowing device. According to the boiler system capable of treating the desulfurization wastewater, the desulfurization wastewater is heated, atomized and sprayed into the hearth through high-temperature, high-pressure and high-speed steam in the soot blower, water in the wastewater is evaporated at high temperature in the hearth, and crystals separated out from the wastewater are adsorbed by slag and coke in the hearth; and meanwhile, slag and cokes on the inner wall of the hearth are crushed under the soot blowing effect, and finally crystals and the cokes fall into an ash hopper below the furnace bottom together.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurization wastewater treatment in thermal power plants, and in particular to a boiler system capable of treating desulfurization wastewater. Background Art

[0002] The boiler is one of the core equipment of thermal power generation. During the coal-burning process, the boiler will produce a large amount of sulfur-containing harmful gases. In order to reduce the pollution of these gases to the environment, a flue gas desulfurization device is usually installed in the flue of the boiler to remove the sulfur-containing substances in the flue gas. However, the flue gas desulfurization device will produce desulfurization wastewater during the desulfurization process, and the desulfurization wastewater is led to the reservoir through a pipeline for storage. The desulfurization wastewater contains a variety of pollutants such as suspended matter, supersaturated sulfites, sulfates and heavy metals. Many of these pollutants are the first category of pollutants that require strict control in the national environmental protection standards. If these wastewaters are discharged directly, they will cause serious pollution to the environment. Therefore, the desulfurization wastewater needs to be treated and the pollutants in the desulfurization wastewater need to be removed before the wastewater can be discharged.

[0003] At present, the desulfurization wastewater is usually treated by spraying the desulfurization wastewater back into the furnace of the boiler. Figure 1As shown, the boiler system for treating desulfurized wastewater in the prior art includes a boiler, an ash hopper 14, a heat exchanger 16, an atomizer 17, a superheater 18, and a soot blower 19. In addition, a water reservoir 151 for storing desulfurized wastewater and a concentration pretreatment device 152 for treating desulfurized wastewater are also provided. Among them, the middle part of the boiler is a furnace 11 as a combustion space, the part below the furnace 11 is a furnace bottom 12 for discharging ash, and the part above the furnace 11 is a flue 13 for exhausting smoke. The bottom of the furnace bottom 12 has an opening, and the ash hopper 14 is arranged below the furnace bottom 12. The opening of the ash hopper 14 is connected to the opening of the furnace bottom 12. The ash hopper 14 is used to receive the ash and coke falling from the furnace 11 and the furnace bottom 12. The water reservoir 151, the concentration pretreatment device 152, the heat exchanger 16, and the atomizer 17 are connected in sequence through pipelines, and the atomizer 17 is connected to the furnace 11. The water reservoir 151 is filled with stored desulfurized wastewater, which is concentrated by the concentration pretreatment device 152, heated by the heat exchange device 16, and then atomized by the atomization device 17 and sprayed into the furnace 11 of the boiler. The heat in the furnace 11 causes the water mist of the desulfurized wastewater to evaporate quickly, and the sulfur-containing pollutants in the wastewater are crystallized and adsorbed by the coke and slag on the inner wall of the furnace 11. The superheater 18 is installed in the flue 13 to reheat the steam generated during the combustion process of the boiler. The reheated steam is led to the soot blower 19 by the pipeline for use. The soot blower 19 is installed outside the furnace 11 and connected to the furnace 11. The soot blower 19 sprays the steam from the superheater 18 into the furnace 11, driving the air in the furnace 11 to form a high-speed airflow. The shear force and impact force generated by the high-speed airflow cause the slag and coke to fall off the inner wall of the furnace 11 , and finally the slag and coke adsorbed with sulfur-containing crystals from the desulfurization wastewater fall into the ash hopper 14 below the furnace bottom 12 .

[0004] However, the boiler system that can treat desulfurization wastewater in the existing technology occupies a large space as a whole and requires high costs for operation and maintenance. Summary of the invention

[0005] Based on this, the purpose of the present invention is to overcome the defects or shortcomings of the prior art and provide a boiler system that can treat desulfurization wastewater.

[0006] A boiler system capable of treating desulfurized wastewater, characterized in that it comprises a boiler, a wastewater inlet main pipe, a steam inlet main pipe and at least one wastewater-sootblowing device; the middle part of the boiler is a furnace of a combustion space; the desulfurized wastewater is introduced to the wastewater-sootblowing device through the wastewater inlet main pipe, and merges with the steam introduced through the steam inlet main pipe in the wastewater-sootblowing device, and the desulfurized wastewater is heated by steam in the wastewater-sootblowing device and then sprayed into the furnace of the boiler together with the steam. The boiler system capable of treating desulfurized wastewater of the present invention utilizes the high-temperature, high-pressure and high-speed steam in the sootblower to heat the desulfurized wastewater and spray it into the furnace in atomization, the water content of the wastewater is evaporated at high temperature in the furnace, the crystals precipitated from the wastewater are adsorbed by the slag and coke in the furnace, and the slag and coke on the inner wall of the furnace are crushed by the sootblowing action, and finally the crystals and coke fall into the ash hopper below the furnace bottom. Compared with the prior art, the boiler system capable of treating desulfurization wastewater of the present invention can simultaneously complete the two actions of soot blowing and desulfurization wastewater treatment, avoids the installation of heat exchange devices and atomization devices, reduces floor space, and reduces energy consumption.

[0007] The wastewater-sootblowing device comprises a steam branch pipe, a wastewater branch pipe, and a sootblowing nozzle arranged at the steam outlet end of the steam branch pipe; the steam branch pipe is connected to the steam inlet main pipe; the wastewater branch pipe is respectively connected to the wastewater inlet main pipe and the steam branch pipe, and after the desulfurization wastewater is heated by steam, it is sprayed into the furnace of the boiler through the sootblowing nozzle together with the steam.

[0008] In one embodiment, at the place where the wastewater branch pipe is connected to the steam branch pipe, the angle formed by the wastewater branch pipe and the steam branch pipe is an acute angle.

[0009] In one embodiment, a pressure reducing valve is provided on the wastewater branch pipe to make the pressure of the desulfurized wastewater in the wastewater branch pipe higher than the steam pressure in the steam branch pipe. The pressure reducing valve reduces the pressure of the desulfurized wastewater in the wastewater branch pipe 42 to maintain it at a safe pressure, and controls the pressure of the desulfurized wastewater in the wastewater branch pipe to be higher than the steam pressure in the steam branch pipe, so that the desulfurized wastewater in the wastewater branch pipe can smoothly enter the steam branch pipe and intersect with the steam, thereby preventing the pipe from being blocked.

[0010] In one embodiment, the wastewater inlet main pipe is provided with a wastewater control main valve; the steam inlet main pipe is provided with a steam control main valve; the steam control sub-valve of each wastewater-sootblowing device is provided on the steam branch pipe, and the wastewater control sub-valve is provided on the wastewater branch pipe upstream of the pressure reducing valve; and a master control unit is also included, which is electrically connected to the wastewater control main valve, the steam control main valve, the wastewater control sub-valve, the steam control sub-valve and the pressure reducing valve. By connecting each valve to the master control unit, the boiler system described in the present invention can be flexibly controlled.

[0011] In one embodiment, the wastewater-sootblowing device is also provided with a connecting pipe connecting the steam branch and the wastewater branch, and the connecting position of the connecting pipe and the wastewater branch is located between the confluence of the desulfurization wastewater and steam and the pressure reducing valve; the connecting position of the connecting pipe and the steam branch is located between the steam control sub-valve and the confluence of the desulfurization wastewater and steam; the angle between the connecting pipe and the steam branch is an acute angle; a check valve is provided on the connecting pipe, so that the steam in the steam branch can pass through the connecting pipe into the wastewater branch, while the desulfurization wastewater in the wastewater branch cannot pass through the connecting pipe into the steam branch.

[0012] The above structure sprays steam into the wastewater branch pipe from the upstream position of the wastewater branch pipe outlet through the connecting pipe to flush the blockage in the wastewater branch pipe and dredge the blockage in the wastewater branch pipe.

[0013] In one embodiment, a thermometer is provided on the steam branch pipe after the desulfurization wastewater and steam are combined; the main control unit adjusts the inlet flow of each valve connected thereto according to the detected temperature of the thermometer; when the main control unit determines that the detected temperature of the thermometer is lower than a preset temperature, the main control unit reduces the inlet flow of the corresponding wastewater control sub-valve, and / or increases the inlet flow of the corresponding steam control sub-valve, thereby increasing the temperature of the wastewater-steam mixture.

[0014] In one embodiment, the preset temperature is greater than or equal to 150 degrees Celsius. The above improvements can ensure the temperature of the water mist sprayed by the wastewater-sootblowing device, and avoid unnecessary thermal expansion and contraction of various components of the boiler, which affects the safety and life of the boiler.

[0015] In one embodiment, a plurality of the wastewater-sootblowing devices are included, and sootblowing is performed at fixed points on different areas of the inner wall of the furnace of the boiler; the boiler system also includes a camera, and the camera takes a coking map on the inner wall of the furnace; the main control unit determines the coking thickness of different areas of the inner wall of the furnace according to the coking map, and when the coking thickness is less than a preset thickness, the main control unit closes the pressure reducing valve and / or wastewater control sub-valve on the wastewater branch pipe of the wastewater-sootblowing device corresponding to the area, so that only steam is sprayed into the wastewater-sootblowing device; when the coking thickness is greater than the preset thickness, the main control unit simultaneously opens the pressure reducing valve and wastewater control sub-valve on the wastewater branch pipe of the wastewater-sootblowing device corresponding to the area, and simultaneously introduces steam and desulfurized wastewater into the wastewater-sootblowing device, so that the desulfurized wastewater is heated by steam and then sprayed into the furnace together with the steam. Through the above improvements, desulfurization wastewater treatment is not carried out when the amount of coking is not large, so as to avoid the coking failing to completely absorb the crystals of desulfurization wastewater and causing it to enter the flue and be adsorbed by fly ash. Only when the amount of coking is sufficient is the wastewater sprayed for treatment.

[0016] In one embodiment, the preset thickness is 1 cm.

[0017] In one embodiment, the wastewater inlet main pipe is provided with a concentration pretreatment device at the upstream position of the slurry pump, and the concentration pretreatment device reduces the water content of the desulfurization wastewater to below 45%. Concentrating the desulfurization wastewater can improve the wastewater treatment efficiency.

[0018] In one embodiment, a gas safety valve is provided on the pipeline between the steam control main valve and the steam control sub-valve. When the steam pressure in the pipeline is higher than the set pressure of the gas safety valve, the steam in the pipeline is sprayed from the gas safety valve into the environment to relieve the pressure. An overflow control valve is provided on the pipeline between the wastewater control main valve and the wastewater control sub-valve. The water outlet of the overflow control valve is connected to the overflow circulation pipeline. When the wastewater pressure in the pipeline is higher than the set pressure of the overflow control valve, the desulfurization wastewater overflows from the overflow control valve to the overflow circulation pipeline.

[0019] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a boiler system installed in the prior art for treating desulfurization wastewater;

[0021] Figure 2 A schematic diagram of the structure of a boiler system capable of treating desulfurization wastewater according to the present invention in one embodiment;

[0022] Figure 3 It is an enlarged structural schematic diagram of the wastewater-sootblowing device;

[0023] Figure 4 This is a connection diagram of the master control unit of the boiler system capable of treating desulfurization wastewater according to the present invention.

[0024] Figure numerals: 11 furnace, 12 furnace bottom, 13 flue, 14 ash hopper, 151 water storage tank, 152 concentration pretreatment device, 16 heat exchange device, 17 atomization device, 18 superheater, 19 soot blower, 20 wastewater inlet main pipe, 21 water inlet pump, 23 slurry pump, 24 wastewater control main valve, 30 steam inlet main pipe, 31 steam control main valve, 41 wastewater-soot blowing device, 42 wastewater branch pipe, 421 wastewater control sub-valve, 422 pressure reducing valve, 43 steam branch pipe, 44 soot blowing nozzle, 431 steam control sub-valve, 45 connecting pipe, 451 check valve DETAILED DESCRIPTION

[0025] like Figure 1As shown, the present invention analyzes the reasons why the boiler system that can treat desulfurization wastewater in the prior art occupies a large space and has a high cost for operation and maintenance, and believes that too many devices are installed outside the boiler, which leads to the large space occupied by the entire boiler system, high energy consumption, and thus high operation and maintenance costs. For example, the reason why the heat exchange device 16 needs to be installed is that the temperature in the furnace 11 is relatively high. In order to avoid the injected desulfurization wastewater from cooling the furnace 11 and affecting the operation of the boiler, and to avoid thermal expansion and contraction causing damage to the boiler equipment, the heat exchange device 16 is required to heat the desulfurization wastewater. The reason why the atomization device 17 needs to be installed is to form fine wastewater droplets as much as possible, which is conducive to the rapid evaporation of water, avoid excessive liquid desulfurization wastewater from causing the temperature of the furnace 11 to decrease, and affect the combustion in the boiler, while also ensuring the treatment effect and efficiency of the desulfurization wastewater. The reason why the soot blower 19 is installed is to knock down the coke and slag attached to the inner wall of the furnace and adsorbed with sulfur crystals containing desulfurization wastewater, so that the sulfur crystals are removed together with the coke and slag. The superheater 18 is provided to cooperate with the operation of the soot blower 19. The installation of numerous devices leads to the problem of large space occupied by the entire boiler system, and the operation and maintenance of these devices also bring about the problem of large energy consumption and high operation and maintenance costs.

[0026] After further observation and analysis, it is found that for the boiler itself, which is mainly used for coal-fired power generation, the soot blower 19 and the superheater 18 matched therewith are indispensable devices as devices for removing ash and slag produced by the fuel; at the same time, the soot blower 19 connected to the furnace 11 itself has the functions of atomization and injection, and the steam used is high-temperature, high-pressure and high-speed steam. Therefore, the soot blower 19 has the potential to replace the heat exchange device 16 and the atomization device 17, and heat and atomize the desulfurization wastewater and spray it into the furnace 11.

[0027] Therefore, in order to reduce the space and energy consumption of the equipment, the present invention first cuts out the heat exchange device 16 and the atomizing device 17, and transforms the soot blower 19, introduces the desulfurized wastewater into the steam injection pipe of the soot blower 19, and the high-temperature, high-pressure and high-speed steam in the soot blower 19 heats the desulfurized wastewater, and then the soot blower 19 atomizes the heated desulfurized wastewater, that is, the wastewater-steam mixture, and sprays it into the furnace 11, and contacts the slag attached to the furnace 11. At the same time, the slag and coke are knocked down by the shear force and impact force of the mixed water mist, and the knocked down slag and coke are further in contact with the mixed water mist in the furnace 11 during the falling process. Under the high temperature of the furnace 11, the water content of the mixed water mist is quickly evaporated, and the harmful substances in the mixed water mist are precipitated to form crystals, which are adsorbed by the slag and fall into the ash hopper 14 below the furnace bottom 12 together with the slag. That is, the present invention intends to simultaneously complete the two actions of soot blowing and desulfurization wastewater treatment through the soot blower 19, avoiding the need to install an additional atomizing device 17 and reducing the space occupied. At the same time, since the steam temperature sprayed by the soot blower 19 is high, the desulfurization wastewater is also heated by the steam while mixing with the steam, so the installation of the heat exchange device 16 can also be reduced, thereby greatly reducing the energy consumption generated by heating the desulfurization wastewater, further reducing the space occupied and energy consumption, and reducing the operation and maintenance costs.

[0028] Based on the above concept, the present invention provides a boiler system capable of treating desulfurization wastewater, which uses an improved sootblower 19 to simultaneously complete sootblowing and wastewater treatment, and has the advantages of reducing the overall floor space of the boiler system capable of treating desulfurization wastewater and reducing energy consumption. The scheme of the present invention is described in detail below in conjunction with the accompanying drawings.

[0029] like Figure 2As shown, the boiler system capable of treating desulfurized wastewater of the present invention comprises a boiler, an ash hopper 14, a water reservoir 151, a wastewater inlet main pipe 20, a superheater 18, a steam inlet main pipe 30 and at least one wastewater-sootblowing device 41. The middle part of the boiler is a furnace 11 as a combustion space, the part below the furnace 11 is a furnace bottom 12 for discharging ash, and the part above the furnace 11 is a flue 13 for exhausting smoke. Among them, the bottom of the furnace bottom 12 has an opening. The ash hopper 14 is arranged below the furnace bottom 12, and its opening is connected to the opening of the furnace bottom 12, and is used to receive the ash and coke falling from the furnace 11 and the furnace bottom 12. The arrangement of the boiler and the ash hopper 14 is the same as the conventional technology, which will not be described in detail here. The desulfurized wastewater is stored in the water reservoir 151. The wastewater inlet main pipe 20 is connected to the water reservoir 151 storing desulfurized wastewater and the wastewater-sootblowing device 41 respectively, and the wastewater inlet main pipe 20 leads the desulfurized wastewater from the water reservoir 151 to the wastewater-sootblowing device 41. The superheater 18 is installed in the flue 13 to reheat the steam in the flue 13; the steam inlet main pipe 30 is connected to the superheater 18 and the wastewater-sootblowing device 41 respectively, and the wastewater-sootblowing device 41 is connected to the furnace 11 of the boiler. The steam inlet main pipe 30 leads the steam from the superheater 18 to the wastewater-sootblowing device 41, and the steam merges with the desulfurized wastewater in the wastewater-sootblowing device 41 to form a wastewater-steam mixture, and the steam heats the desulfurized wastewater while merging; the wastewater-sootblowing device 41 atomizes the wastewater-steam mixture into a mixed water mist and sprays it into the furnace 11 of the boiler. The moisture in the mixed water mist is evaporated by high temperature in the furnace 11, and the harmful substances in the mixed water mist are precipitated to form crystals. The crystals are adsorbed by the slag and coke in the furnace 11. At the same time, the slag and coke on the inner wall of the furnace 11 can be broken by the soot blowing action, and finally the crystals and coke fall into the ash hopper 14 below the furnace bottom 12 together.

[0030] The water inlet end of the wastewater inlet main pipe 20 is connected to the water reservoir 151, and the water outlet end is connected to the wastewater-soot blowing device 41, and the water inlet pump 21, the conventional concentration pretreatment device 152, the slurry pump 23, and the wastewater control main valve 25 are arranged in sequence along the water flow direction. The water inlet pump 21 is used to pump the desulfurized wastewater into the wastewater inlet main pipe 20; the concentration pretreatment device 152 is used to concentrate the desulfurized wastewater and reduce the water content of the desulfurized wastewater to below 45% to improve the heating efficiency and treatment efficiency of the wastewater; the slurry pump 23 pumps the concentrated and thick desulfurized wastewater to the downstream wastewater-soot blowing device 41; the wastewater control main valve 25 is used to control the on-off and inflow flow of the desulfurized wastewater in its downstream pipeline and the wastewater-soot blowing device 41.

[0031] The superheater 18 is installed in the flue 13 to reheat the steam in the flue. The superheater 18 is a conventional superheater 18 installed in the boiler flue 13. The air inlet end of the steam inlet main pipe 30 is connected to the superheater 18, and the steam outlet end is connected to the wastewater-sootblowing device 41, and a steam control main valve 31 is provided thereon to control the on-off and flow rate of the steam in the pipeline. Steam enters the steam inlet main pipe 30 from the superheater 18, and passes through the steam inlet main pipe 30 to the wastewater-sootblowing device 41. The method of leading the steam of the superheater 18 to the wastewater-sootblowing device 41 through the steam inlet main pipe 30 is the same as the conventional method of leading the steam from the superheater 18 to the conventional sootblower 19, which will not be repeated here.

[0032] Each of the wastewater-sootblowing devices 41 includes a sootblowing gun and a wastewater branch pipe 42. The sootblowing gun includes a steam branch pipe 43 and a sootblowing nozzle 44. Figure 2 and 3 As shown, the steam inlet of the steam branch pipe 43 is connected to the steam inlet main pipe 30, and the connection position is downstream of the steam control main valve 31, which is the steam outlet end of the steam inlet main pipe 30; the steam branch pipe 43 is provided with a steam control sub-valve 431; the steam outlet of the steam branch pipe 43 is provided with a soot blowing nozzle 44, and the soot blowing nozzle 44 extends into the furnace 11 of the boiler. The water inlet of the wastewater branch pipe 42 is connected to the wastewater inlet main pipe 20, and the connection position is downstream of the wastewater control main valve 24, which is the water outlet end of the wastewater inlet main pipe 20; and the wastewater branch pipe 42 is provided with a wastewater control sub-valve 421. The outlet of the wastewater branch pipe 42 is connected to the steam branch pipe 43, and the connection position is located between the sootblowing nozzle 44 of the steam branch pipe 43 and the steam control valve 431. Wastewater can enter the steam branch pipe 43 from the wastewater branch pipe 42, merge with the steam to form a wastewater-steam mixture and flow to the sootblowing nozzle 44.

[0033] The above-mentioned control valves can control the on-off and inflow flow of steam or wastewater in the pipeline. When the steam control main valve 31 and the steam control sub-valve 431 are opened, and the wastewater control main valve 24 and the wastewater control sub-valve 421 are closed, the high-temperature, high-pressure and high-speed steam flows from the steam inlet of the steam inlet main pipe 30 to the sootblowing gun of the wastewater-sootblowing device 41, passes through the steam branch pipe 43, and is sprayed into the furnace 11 of the boiler from the sootblowing nozzle 44. At this time, the wastewater-sootblowing device only plays the role of decoking of the conventional sootblower 19. When the wastewater control sub-valve 421 and the wastewater control sub-valve 421 are opened, the desulfurized wastewater enters the steam branch pipe 43 from the wastewater branch pipe 42, merges with the high-temperature, high-pressure and high-speed steam to form a wastewater-steam mixture and flows to the sootblowing nozzle 44, and is finally atomized into a mixed water mist by the sootblowing nozzle 44 and sprayed into the furnace 11. The water content of the mixed water mist is evaporated by the heat of the furnace 11 in the furnace 11, and the crystals of harmful substances in the wastewater are precipitated. The crystals are adsorbed by the inner wall of the furnace 11 and the knocked-down slag and coke, and are finally knocked down or dropped into the ash hopper 14 below the furnace bottom 12. At this time, the treatment of the desulfurized wastewater is completed. Since the wastewater is atomized by steam and the soot blowing nozzle in the wastewater-soot blowing device 41, the installation of the atomizing device 17 is reduced, saving space. At the same time, since the temperature of the steam is relatively high, the desulfurized wastewater is also heated by the steam in the process of merging with the steam in the steam branch pipe 43, saving the space for the additional installation of the heat exchange device 16 and the energy consumption generated by the operation. Therefore, the boiler system capable of treating desulfurized wastewater according to the present invention reduces the overall occupied space, reduces the energy consumption caused by the equipment, and can also perform soot blowing and decoking at the same time.

[0034] Furthermore, the present invention found that the pipeline of the boiler system is prone to blockage at the intersection of wastewater and steam. After observation and analysis, it was found that due to the high pressure of steam, if the pressure of the desulfurized wastewater in the wastewater branch pipe 42 is not high enough, it is not easy to enter the steam branch pipe 43 from the wastewater branch pipe 42, and finally the thick and turbid desulfurized wastewater is blocked at the outlet of the wastewater branch pipe 42. Therefore, the present invention improves the above boiler system: Figure 3 As shown, at the connection point between the wastewater branch pipe 42 and the steam branch pipe 43, the angle formed by the wastewater branch pipe 42 and the steam branch pipe 43 is set to be an acute angle, that is, the angle between the flow direction of the wastewater and the flow direction of the steam is an acute angle, which is conducive to the wastewater from the wastewater branch pipe 42 to the steam branch pipe 43. In this embodiment, the angle is preferably 45 degrees. At the same time, a pressure reducing valve 422 is added to the wastewater branch pipe 42 downstream of the wastewater control sub-valve 421. The pressure reducing valve 422 reduces the pressure of the desulfurized wastewater in the wastewater branch pipe 42 or maintains it at a safe pressure, while controlling the pressure of the desulfurized wastewater in the wastewater branch pipe 42 to be higher than the steam pressure in the steam branch pipe 43, so that the desulfurized wastewater can more easily enter the steam branch pipe 43 from the wastewater branch pipe 42. Among them, the pressure reducing valve 422 can be specifically a hydraulic valve or a pneumatic valve.

[0035] Furthermore, if Figure 3 As shown, the wastewater-sootblowing device 41 is also provided with a connecting pipe 45 connecting the steam branch pipe 43 and the wastewater branch pipe 42. One end of the connecting pipe 45 is connected to the wastewater branch pipe 42, and the connecting position is located between the water outlet of the wastewater branch pipe 42 and the pressure reducing valve 422; the other end of the connecting pipe 45 is connected to the steam branch pipe 43, and the connecting position is located between the steam control sub-valve 431 on the steam branch pipe 43 and the water outlet of the wastewater branch pipe 42. The connecting pipe 45 is provided with a check valve 451 at a position close to the wastewater branch pipe 42, so that the steam in the steam branch pipe can pass through the connecting pipe into the wastewater branch pipe, while the desulfurized wastewater in the wastewater branch pipe cannot pass through the connecting pipe into the steam branch pipe. The check valve 451 is preferably a heavy hammer check valve. The connection part between the connecting pipe 45 and the steam branch pipe 43 is smoothly connected, and the angle between the connecting pipe 45 and the steam branch pipe 43 is an acute angle, that is, the angle between the connecting pipe 45 and the steam flow direction in the steam branch pipe 43 is an acute angle, which is conducive to the steam entering the connecting pipe 45 from the steam branch pipe 43, and then spraying into the wastewater branch pipe 42 from the upstream position of the water outlet of the wastewater branch pipe 42. When the wastewater and steam control valves are opened, that is, the wastewater branch pipe 42 and the steam branch pipe 43 are respectively passed through wastewater and steam, the check valve 432 is in a closed state, and steam cannot pass from the steam branch pipe 43 through the connecting pipe 45 into the wastewater branch pipe 42. When the wastewater control sub-valve 421 and / or the wastewater control main valve 24 are closed, and the steam control main valve 31 and the steam control sub-valve 431 are opened, steam flows into the steam branch pipe 43, but wastewater does not flow into the wastewater branch pipe 42, then the check valve 432 is pushed open by the steam, and steam is unidirectionally sprayed into the wastewater branch pipe 42 through the connecting pipe 45, and the sprayed steam plays a role in clearing the blockage of the wastewater branch pipe 42. When the steam control sub-valve 431 and / or the steam control main valve 31 are closed, and steam does not flow into the steam branch pipe 43, that is, the soot blowing work is stopped, the check valve 431 is reset and restored to the closed state.

[0036] The above improvement solves the problem of easy blockage at the intersection of wastewater and steam, that is, by controlling the opening and closing of each valve, steam is sprayed on the wastewater branch pipe 42 to clear the blockage when only steam is sprayed but not wastewater.

[0037] Furthermore, at least one soot blowing area is provided at the furnace 11 of the boiler, and each soot blowing area includes at least one wastewater-soot blowing device 41. In one embodiment, Figure 2As shown, the boiler system includes two sootblowing areas, each sootblowing area includes a wastewater-sootblowing device 41, and the two sootblowing areas are installed on the same side of the furnace 11, and are respectively located at the furnace 11 at a height of 40 meters and 45 meters from the furnace bottom 12 of the boiler. In another embodiment, the boiler system includes two sootblowing areas, which are respectively located at the furnace 11 at a height of 35 meters and 45 meters from the furnace bottom 12 of the boiler; each sootblowing area includes two wastewater-sootblowing devices 41, and the two wastewater-sootblowing devices 41 of the same sootblowing area are respectively installed on both sides of the furnace 11. By setting different sootblowing areas, fixed-point sootblowing can be performed on different areas of the inner wall of the furnace of the boiler. The position and number of the sootblowing area and the wastewater-sootblowing device 41 can be flexibly set according to the size and characteristics of the boiler furnace, so that the coke and slag in various parts of the furnace can be fully utilized for desulfurization wastewater treatment, thereby improving the wastewater treatment efficiency.

[0038] The above improvements enable the boiler system described in the present application to more evenly spray wastewater or steam into the furnace 11 and more fully utilize the coking in the furnace 11 to treat the desulfurization wastewater.

[0039] Furthermore, in order to more conveniently control the amount of wastewater and steam introduced into each area, a master control unit is added to the boiler system, and the wastewater control main valve 24, the steam control main valve 31, the wastewater control sub-valve 421 of each wastewater-sootblowing device 41, the steam control sub-valve 431 and the pressure reducing valve 422 are all connected to the master control unit, and the opening and closing of the valves are controlled by the master control unit, that is, the master control unit can manage and control each sootblowing area and the wastewater-sootblowing device 41 separately. In this embodiment, the master control unit is a PID system, and the operator can use the PID system to control each valve to achieve regional control and management of each sootblowing area.

[0040] Furthermore, due to the complex conditions of the boiler components, it is necessary to continuously adjust the valves according to the conditions of the boiler and the components to control the flow of wastewater and steam in the pipelines of the wastewater-sootblowing device 41. Figure 4 The present invention adds a detection unit to the boiler system to detect the status of the boiler and its components, and connects the devices of the detection unit to the master control unit so that the monitoring data is transmitted to the master control unit. According to the monitoring data, each valve can be controlled and regulated manually or automatically through the master control unit.

[0041] Specifically, the detection unit includes a thermometer, which is arranged on the steam branch pipe 43 of the wastewater-sootblowing device 41, between the water outlet of the wastewater branch pipe 42 and the sootblowing nozzle 44, and is used to measure the temperature of the wastewater-steam mixture. The thermometer is connected to the main control unit, and the main control unit can control the flow rate of each valve connected thereto according to the detection temperature of the thermometer, thereby adjusting the flow ratio of the desulfurized wastewater and steam in the steam branch pipe 43. Specifically, when the main control unit receives and determines that the detection temperature of the thermometer is lower than a preset temperature, the main control unit reduces the flow rate of the corresponding wastewater control sub-valve 421, and / or increases the flow rate of the corresponding steam control sub-valve 431, so as to increase the temperature of the wastewater-steam mixture, and finally stabilize the temperature above the preset temperature. Since the temperature of the wastewater-steam mixture sprayed into the furnace 11 is preferably above 150°C, the preset temperature should be greater than or equal to 150°C, and is preferably 180°C in one embodiment. The above improvements can ensure the temperature of the water mist sprayed by the wastewater-sootblowing device 41, and avoid unnecessary thermal expansion and contraction of the boiler components, which may affect the safety and life of the boiler. Furthermore, an upper limit temperature can be set. When the main control unit receives and determines that the detection temperature of the thermometer is higher than the upper limit temperature, the main control unit can appropriately increase the inflow of the wastewater control sub-valve 421 corresponding to the thermometer, or increase the inflow of the corresponding wastewater control sub-valve 421 while reducing the inflow of the steam control sub-valve 431, so as to improve the efficiency of wastewater treatment and reduce the energy consumption of heating wastewater by reducing the amount of steam used. In one embodiment, the upper limit temperature is set to 400°C. When the detected temperature is higher than 400°C, the main control unit controls the wastewater control sub-valve 421 and the steam control sub-valve 431, appropriately increases the flow rate of wastewater entering the steam branch pipe 43 and reduces the flow rate of steam, maintains the temperature of the steam-water mixture between 180-400°C, and maximizes the treatment efficiency of desulfurization wastewater while meeting the preset temperature requirements.

[0042] Furthermore, the present invention has found that although the wastewater-sootblowing device 41 is only provided in the furnace 11, and the coke in the furnace 11 is used to adsorb the wastewater crystals, a certain amount of pollutant crystals from the desulfurization wastewater are still occasionally found in the fly ash in the flue 13 of the boiler. The fine particulate matter in the flue gas after the combustion of coal usually accumulates in the flue 13. Unlike the coke and ash in the furnace 11 of lower value, the fly ash in the flue 13 has a higher reuse value after recovery. Fly ash can be fired together with raw materials such as lime and gypsum to form cement clinker, which can be used for cement production, road construction, brick and tile production, etc. It can also be used for soil improvement, filling materials, etc. However, the mixing of crystals of pollutants in the desulfurization wastewater will affect the utilization value of the recycled fly ash and increase the processing cost of the fly ash. The present invention has analyzed this situation and found that the wastewater-sootblowing device of the boiler system of the present invention also mixes desulfurized wastewater to form a mixed spray for spraying on the basis of the original steam injection, so that the sootblowing and decoking speed of the wastewater-sootblowing device of the present boiler system is faster than the decoking speed of the conventional sootblower 19. When most of the coke is removed and the amount of coke on the inner wall of the furnace 11 is small, the coke in the furnace 11 does not completely adsorb the crystals of the desulfurized wastewater, and the light fine granular crystals are brought to the flue 13 by the high-temperature flue gas and adsorbed by the fly ash in the flue 13. In order to ensure that the crystals of the desulfurized wastewater are fully adsorbed by the coke in the furnace 11 and fall into the ash hopper 14 below the furnace bottom 12 with the coke, the present invention studies the thickness of the coke and the decoking speed, and concludes that: when the coke thickness on the inner wall of the furnace 11 is greater than 1 cm, the coke can fully adsorb the crystals of the desulfurized wastewater ejected together with the steam, and the crystals fall into the ash hopper 14 together with the coke and will not enter the flue 13 and be adsorbed by the fly ash.

[0043] Based on this, the detection unit of the present invention also includes a panoramic camera, which is arranged at a high place in the furnace 11, and can capture the coking image on the inner wall of different soot blowing areas of the furnace 11, and transmit the image to the main control unit for processing. The image of the inner wall of the furnace 11 without coking can clearly observe the components on the inner wall of the furnace 11. When there is coking, irregular coking attachments will appear. The main control unit compares the images before and after coking sent back by the panoramic camera and judges the coking thickness of different soot blowing areas. The specific shooting method, image comparison and thickness judgment method are all conventional techniques and are not repeated here. When the main control unit judges that the coking thickness of a soot blowing area in the furnace 11 is less than a preset thickness based on the coking image sent back by the panoramic camera, the main control unit locks the wastewater corresponding to the soot blowing area The pressure reducing valve 422 and the wastewater control sub-valve 421 on the wastewater branch pipe 42 of the soot blowing device, does not spray desulfurization wastewater but only retains the injection of steam, and reduces the decoking rate. In this embodiment, the preset thickness is 1 cm. When the main control unit determines that the coking thickness in a certain area of ​​the furnace 11 is greater than 1 cm through the panoramic camera, the main control unit simultaneously opens the pressure reducing valve 422 and the wastewater control sub-valve 421 on the wastewater branch pipe 42 of the wastewater-sootblowing device corresponding to the sootblowing area, and passes desulfurized wastewater, and at the same time passes steam and desulfurized wastewater into the wastewater-sootblowing device 41, so that the desulfurized wastewater is heated by steam and then sprayed into the furnace together with the steam. The amount of coking at this time is sufficient to fully absorb the crystals in the desulfurized wastewater and fall into the ash hopper 14 together with the crystals.

[0044] Furthermore, since the pressure in each pipeline is relatively high, in order to ensure the safety of the pipeline, a gas safety valve is provided on the pipeline between the steam control main valve 31 and the steam control sub-valve 431. The set pressure of the gas safety valve is set to be higher than the working pressure of the steam in the steam pipeline by more than 0.5MPa, preferably 0.5MPa. When the steam pressure in the pipeline is higher than the set pressure of the gas safety valve, the steam in the pipeline is sprayed from the gas safety valve into the environment for pressure relief. Similarly, an overflow control valve is provided on the pipeline between the wastewater control main valve 24 and the wastewater control sub-valve 421. The set pressure of the overflow control valve is set to be higher than the working pressure of the wastewater in the pipeline by more than 0.5MPa, preferably 0.5MPa. When the wastewater pressure in the wastewater pipeline is higher than the set pressure of the overflow control valve, the wastewater in the pipeline overflows from the overflow control valve and is discharged into the environment for pressure relief.

[0045] Furthermore, considering that the overflowed desulfurized wastewater is still untreated, the outlet of the overflow control valve is connected to the desulfurized wastewater reservoir 151 through an overflow circulation pipe. When the wastewater pressure in the wastewater pipe is higher than the set pressure of the overflow control valve, the wastewater in the wastewater pipe overflows from the overflow control valve and returns to the desulfurized wastewater reservoir 151 through the overflow circulation pipe, and finally enters the boiler system of the present invention again from the wastewater inlet main pipe 20.

[0046] Compared with the prior art, the boiler system for treating desulfurization wastewater provided by the present invention has the following advantages:

[0047] 1. By improving the soot blower 19 of the original boiler system that can treat desulfurized wastewater, a wastewater-soot blowing device 41 is formed, so that the desulfurized wastewater and steam are combined in the wastewater-soot blowing device 41, and the desulfurized wastewater is heated, atomized and sprayed into the furnace 11 for desulfurized wastewater treatment, thereby reducing the installation of the heating device 15 and the atomizing device 17, saving the space occupied by the equipment and energy consumption.

[0048] 2. Through the improvement of the present invention, the boiler system capable of treating desulfurization wastewater has both the functions of decoking and treating desulfurization wastewater.

[0049] 3. By setting the angle between the steam branch pipe 43 and the wastewater branch pipe 42 to be an acute angle and adding a connecting pipe 45 and a check valve 451, the intersection of wastewater and steam is no longer prone to blockage.

[0050] 4. The boiler system can be provided with multiple soot blowing areas in the furnace 11, and the master control unit can be used for zone control. The coking in various parts of the furnace 11 can be used to the maximum extent for desulfurization wastewater treatment according to the situation, and flexible regulation can be performed at the same time.

[0051] 5. The temperature of the steam-water mixture sprayed into the furnace 11 can be controlled above 150 degrees, avoiding adverse thermal expansion and contraction of the boiler equipment when the steam-water mixture is sprayed into the boiler in an atomized form, thereby ensuring the safety and service life of the boiler.

[0052] 6. By judging the coke thickness through a panoramic camera and adjusting the injection of the mixed spray, it can be ensured that the crystals of the desulfurization wastewater can be fully adsorbed by the coke in the furnace 11 and fall into the ash hopper 14 below the furnace bottom 12 together with the coke, and avoid the wastewater crystals from entering the flue 13 and being adsorbed by the fly ash, affecting the recycling of the fly ash in the flue 13.

[0053] 7. By adding an overflow control valve and a wastewater circulation pipeline, the overflowing desulfurization wastewater is allowed to flow back to the desulfurization wastewater reservoir 151 while maintaining the pipeline pressure, thereby preventing untreated desulfurization wastewater from entering the environment.

[0054] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items. When the above description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of the present application, for those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0055] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A boiler system capable of treating desulfurization wastewater, characterized in that: It includes a boiler, a wastewater inlet main pipe, a steam inlet main pipe and at least one wastewater-sootblowing device; the middle part of the boiler is a furnace serving as a combustion space; the desulfurized wastewater is introduced to the wastewater-sootblowing device through the wastewater inlet main pipe, and merges with the steam introduced through the steam inlet main pipe in the wastewater-sootblowing device; the desulfurized wastewater is heated by steam in the wastewater-sootblowing device and then sprayed into the furnace of the boiler together with the steam.

2. The boiler system according to claim 1, characterized in that: The wastewater-sootblowing device comprises a steam branch pipe, a wastewater branch pipe, and a sootblowing nozzle arranged at the steam outlet end of the steam branch pipe; the steam branch pipe is connected to the steam inlet main pipe; the wastewater branch pipe is respectively connected to the wastewater inlet main pipe and the steam branch pipe; after the desulfurization wastewater is heated by steam, it is sprayed into the furnace of the boiler through the sootblowing nozzle together with the steam.

3. The boiler system according to claim 2, characterized in that: At the place where the wastewater branch pipe is connected to the steam branch pipe, an angle formed by the wastewater branch pipe and the steam branch pipe is an acute angle.

4. The boiler system according to claim 3, characterized in that: The wastewater branch pipe is provided with a pressure reducing valve so that the pressure of the desulfurized wastewater in the wastewater branch pipe is higher than the steam pressure in the steam branch pipe.

5. The boiler system according to claim 4, characterized in that: The wastewater inlet main pipe is provided with a wastewater control main valve; the steam inlet main pipe is provided with a steam control main valve; the steam branch pipe is provided with a steam control sub-valve, and a wastewater control sub-valve is also provided on the wastewater branch pipe upstream of the pressure reducing valve; and a main control unit is also included to control the opening and closing of the wastewater control main valve, the steam control main valve, the wastewater control sub-valve, the steam control sub-valve and the pressure reducing valve respectively.

6. The boiler system according to claim 5, characterized in that: The wastewater-sootblowing device is also provided with a connecting pipe connecting the steam branch and the wastewater branch, and the connecting position of the connecting pipe and the wastewater branch is located between the confluence of the desulfurization wastewater and steam and the pressure reducing valve; the connecting position of the connecting pipe and the steam branch is located between the steam control sub-valve and the confluence of the desulfurization wastewater and steam; the angle between the connecting pipe and the steam branch is an acute angle; a check valve is provided on the connecting pipe, so that the steam in the steam branch can pass through the connecting pipe into the wastewater branch, while the desulfurization wastewater in the wastewater branch cannot pass through the connecting pipe into the steam branch.

7. The boiler system according to claim 6, characterized in that: A thermometer is provided on the steam branch pipe after the desulfurization wastewater and steam are combined; the main control unit adjusts the inlet flow of each valve connected thereto according to the detected temperature of the thermometer; when the main control unit determines that the detected temperature of the thermometer is lower than a preset temperature, the main control unit reduces the inlet flow of the corresponding wastewater control sub-valve, and / or increases the inlet flow of the corresponding steam control sub-valve, so as to increase the temperature of the wastewater-steam mixture.

8. The boiler system according to claim 7, characterized in that: The preset temperature is greater than or equal to 150 degrees Celsius.

9. The boiler system according to claim 7, characterized in that: The invention comprises a plurality of the wastewater-sootblowing devices, which respectively carry out fixed-point sootblowing on different areas of the inner wall of the furnace of the boiler; the boiler system also comprises a camera, which takes a picture of the coking on the inner wall of the furnace; the main control unit determines the coking thickness of different areas of the inner wall of the furnace according to the coking picture, and when the coking thickness is less than a preset thickness, the main control unit closes the pressure reducing valve and / or the wastewater control sub-valve on the wastewater branch pipe of the wastewater-sootblowing device corresponding to the area, so that only steam is sprayed into the wastewater-sootblowing device; when the coking thickness is greater than the preset thickness, the main control unit simultaneously opens the pressure reducing valve and the wastewater control sub-valve on the wastewater branch pipe of the wastewater-sootblowing device corresponding to the area, and simultaneously introduces steam and desulfurized wastewater into the wastewater-sootblowing device, so that the desulfurized wastewater is heated by the steam and then sprayed into the furnace together with the steam.

10. The boiler system according to claim 9, characterized in that: The preset thickness is 1 cm.

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