A flash steam production method and system for a sulfur combustion furnace sleeve-type waste heat boiler

Abstract

A method and system for flash steam production in a sleeve-type waste heat boiler of a sulfur combustion furnace belongs to the field of salt chemical industry and waste heat recovery technology. In order to solve the problem of waste heat from high-temperature SO2 flue gas in the process of preparing SO2 in a sulfur combustion furnace, the present application sets up another shell outside the non-insulated shell of the sulfur combustion furnace. The annular area between the two serves as a heat exchange area. Nitrogen or air is used as the heat exchange medium. Heat exchange is carried out through the combustion furnace shell. The nitrogen temperature rises, and the flue gas temperature in the furnace gradually decreases and is discharged. After heating, the nitrogen is sent to a micro high-temperature waste heat hot water boiler, and heat is exchanged with high-temperature waste heat water through a heat exchanger. The cooled nitrogen is returned and circulated for heat exchange. The heated high-temperature waste heat water is sent to downstream heat users and continues to be circulated for heating; or it is sent to a flash tank for flash evaporation. The flash steam pressure of 0.1 to 0.6 MPa is supplied as process steam, which can achieve a large recovery of flue gas waste heat while maintaining normal sulfur combustion.

Description

Technical Field

[0001] The invention relates to a flash steam production method and system for a sleeve-type waste heat boiler of a sulfur combustion furnace, belonging to the technical field of salt chemical industry and waste heat recovery. Background Art

[0002] Salt chemical plants based on seawater salt production can extract bromine, lithium and other substances from seawater or concentrated bittern after salt production. The basic principle of the commonly used "chlorine oxidation air blowing method to produce bromine" is as follows.

[0003] Under acidic conditions, using chlorine as an oxidant, bromide ions (Br-) are oxidized into bromine molecules (Br2). The ion reaction formula is as follows.

[0004] 2Br-+Cl2= Br2+2 Cl-.

[0005] The free bromine is blown out with air, so it is called the air blowing method.

[0006] Acidic bromine production uses sulfur dioxide as the absorbent and fresh water spray to assist in absorbing the mixture of air and bromine. The absorbed liquid is called primary acid. The chemical reaction formula is as follows.

[0007] Br2+SO2+2H2O=2HBr+H2SO4.

[0008] Chlorine gas is passed into the primary acid for oxidation, bromine is liberated again, and hydrochloric acid is generated. The chemical reaction formula is as follows.

[0009] 2HBr+Cl2=2HCl+Br2.

[0010] Finally, the bromine is distilled out with water vapor and separated by condensation to obtain the finished bromine.

[0011] The process flow is described as follows.

[0012] Seawater (brine) is pumped to the blow-out tower. Dilute acid and chlorine are added to the pump's outlet pipe. The mixed, acidified, chlorinated brine is sprayed down from the top of the blow-out tower. A blower draws air in from the bottom of the tower. As the brine and air come into contact, the free bromine in the brine is released. The waste liquid is discharged from the bottom of the blow-out tower and sent to the salt pan for drying. The mixed gas exiting the top of the blow-out tower is fed into the absorption tower, where it is absorbed by sulfur dioxide and water mist. The resulting finished liquid, called primary acid, is collected in an acid storage tank. After purification by a mist trap, the air is blown by a blower and enters the bottom of the blow-out tower for recycling within the system. Primary acid is added at the top of the distillation tower, while water vapor and chlorine are introduced from the bottom. As the primary acid flows down the packing, it comes into contact with the chlorine and water vapor flowing upward, causing it to be continuously oxidized and distilled. The bromine vapor and water vapor mixture is discharged from the top of the tower and condensed and separated to produce liquid bromine. The crude bromine water returns to the absorption tower for continued circulation.

[0013] Among them, chlorine is usually produced by vaporizing liquid chlorine in a water bath. The process is as follows: liquid chlorine is sent into a water bath bottle, the bottle mouth of which is tightly connected to the chlorine clamp, the chlorine water bath is filled with water and steam is used to heat the water in the bath, and the temperature is controlled by a solenoid valve at 75℃-83℃. This temperature range can realize the vaporization of liquid chlorine and avoid the formation of nitrogen trichloride explosives. The vaporized chlorine is supplied.

[0014] The preparation process of SO2 gas is as follows: sulfur enters the sulfur combustion furnace through the distributor, and burns with the oxygen in the blown air at high temperature to generate sulfur dioxide gas. After air cooling and circulating water washing cooling, the temperature is controlled below 70°C, and then enters the blowing and absorption tower for reduction absorption to produce bromine production complete liquid.

[0015] The bromine extraction distillation process is as follows: after the finished liquid is preheated by the recovered liquid, it enters the distillation tower to be oxidized by chlorine, and water vapor distillation is carried out at the same time, the bromine is evaporated, and the temperature at the top of the tower is controlled at 80-90 ° C. After condensation, crude bromine is obtained. The recovered bromine liquid is cooled by brine heat exchange and enters the collection tank, and then used for brine acidification.

[0016] The traditional seawater bromine extraction process described above exhibits significant energy waste. For example, the high-temperature flue gas (reaching 600-700°C) produced during the production of SO2 gas in a sulfur combustion furnace is typically not recycled due to its high corrosiveness and low volume. Instead, it is directly sprayed into a water scrubber to cool it down to 50-60°C. The discharged waste sulfuric acid (SH) is also typically not recycled due to its extremely corrosive nature, low flow rate, and low temperature grade, ultimately wasting it. Although a special heat exchanger is typically installed to recover some of the waste heat from the bromine recovery liquid discharged from the bromine extraction distillation tower, the existing special heat exchangers have poor heat transfer performance and are very expensive, resulting in a relatively small amount of waste heat recovery. As a result, the discharge temperature of the bromine recovery liquid is often still as high as 50-60°C, wasting the waste heat from the low-temperature section. This also results in the addition of relatively more water vapor, resulting in higher energy consumption and operating costs. In short, since the flue gas and discharged process water are highly corrosive and have a small flow rate, a large proportion of various waste heat resources are wasted. Under the current dual-carbon policy background, it is even more necessary to recycle and reuse them to achieve energy saving and consumption reduction. Summary of the Invention

[0017] The purpose and task of the present invention is to address the inherent technical limitations of the above-mentioned seawater bromine extraction process by setting a sleeve shell outside the sulfur combustion furnace, extracting heat from the annular area with nitrogen or air, then heating high-temperature water, and recovering the waste heat of the high-temperature flue gas through flash steam production, and using it for process production and heating domestic hot water.

[0018] The specific description of the present invention is: a sulfur combustion furnace sleeve type waste heat boiler flash steam production system, which is composed of the original combustion furnace and SO2 flue gas water washing tower subsystem and the combustion furnace body heat extraction and flash steam production boiler subsystem and its connecting pipes and components, wherein the original combustion furnace and SO2 flue gas water washing tower subsystem includes a sulfur combustion furnace 1, an ash settling tank 2, a high-temperature SO2 flue 3, a water washing tower 4, a clean SO2 flue pipe 5, a Roots blower 6, a water washing pump 7, an absorption tower 9 and its connecting pipes and components, and is characterized in that the The combustion furnace body heat extraction and flash steam production boiler subsystem includes a heat exchange sleeve 20, a micro high-temperature waste heat hot water boiler 10, a water supply pump 16, a flash tank 23, a blower 21, a compressed working medium gas storage tank 22, a mixing damper 19 and its connecting pipes and components. The heat exchange sleeve 20 is arranged on the outside of the shell of the sulfur combustion furnace 1, and the closed annular space between the two is the area where the heat exchange working medium flows and exchanges heat. The air inlet of the heat exchange sleeve 20 is arranged at one end of the smoke outlet of the sulfur combustion furnace 1, and the outlet of the heat exchange sleeve 20 is arranged at one end of the smoke outlet of the sulfur combustion furnace 1. The outlet is arranged at one end of the air inlet of the sulfur combustion furnace 1; the air outlet of the heat exchange sleeve 20 is connected to the high-pressure inlet of the mixing damper 19 and the inlet of the inlet rectifying section 11 of the micro high-temperature waste heat hot water boiler 10, and the micro high-temperature waste heat hot water boiler 10 also includes a shell 12, an ultra-large temperature difference heat exchanger 13 and an outlet tapering section, the medium-temperature heat exchange medium outlet of the outlet tapering section is connected to the low-pressure outlet of the mixing damper 19, the inlet of the blower 21 and the air outlet of the compressed medium gas storage tank 22, and the air outlet of the blower 21 is connected to the air inlet of the heat exchange sleeve 20. The water inlet of the ultra-large temperature difference heat exchanger 13 is connected to the outlet of the water feed pump 16, the water outlet of the ultra-large temperature difference heat exchanger 13 is connected to the inlet of the water supply regulating valve 25 and the inlet of the bypass regulating valve 24, the outlet of the water supply regulating valve 25 is connected to the water supply pipe of the high-temperature water supply G, the outlet of the bypass regulating valve 24 is connected to the high-temperature water inlet of the flash tank 23, the steam outlet of the flash tank 23 is connected to the steam supply pipe of the secondary steam Q, and the medium-temperature water outlet of the flash tank 23 is connected to the inlet of the water feed pump 16 and the water pipe of the high-temperature return water H.

[0019] A safety valve group 14 and a water supply temperature sensor 15 are provided on the water outlet pipe section of the ultra-large temperature difference heat exchanger 13, a medium-temperature mixed gas sensor 18 is provided on the medium-temperature heat exchange working medium outlet pipe section of the micro high-temperature waste heat hot water boiler 10, and a combustion furnace exhaust temperature sensor 17 is provided on the high-temperature SO2 flue 3 at the flue gas outlet of the sulfur combustion furnace 1.

[0020] The operating temperature of the water supply temperature sensor 15 is controlled by the opening of the electric regulating valve at the outlet of the water supply pump 16; the lower limit temperature of the medium-temperature mixed gas sensor 18 is controlled by the opening of the mixing air door 19; the lower limit temperature of the combustion furnace exhaust temperature sensor 17 is controlled by the flow rate adjusted by the blower 21 through the frequency converter or the air inlet guide vane.

[0021] The working method of the flash steam generation system of the sulfur combustion furnace sleeve type waste heat boiler is as follows.

[0022] 1. The working process of the flash steam production system of the sleeve-type waste heat boiler of the sulfur combustion furnace is as follows: before starting the sulfur combustion furnace 1, the combustion furnace body heat extraction and flash steam production boiler subsystem are started first, wherein the blower 21 is started, the air supply valve of the compressed working medium gas storage tank 22 is opened, and the mixing damper 19 is opened; then the sulfur combustion furnace 1 and the original combustion furnace and SO2 flue gas water washing tower subsystem are started, at this time the blower 21 is started to send the heat exchange working medium into the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange sleeve 20, and the heat exchange working medium is heated and sent to ... working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange The inlet rectifying section 11 of the micro high-temperature waste heat hot water boiler 10; at this time, the water supply pump 16 is started and the boiler feed water is sent to the ultra-large temperature difference heat exchanger 13 to exchange heat with the heat exchange medium on the other side. After the heat exchange medium is cooled, it returns to the inlet of the blower 21 to continue the circulation heat exchange; the high-temperature outlet water of the ultra-large temperature difference heat exchanger 13 is divided into two paths, one of which is sent to the downstream high-temperature hot water heat user, and the other is sent to the flash tank 23 for flash evaporation. The secondary steam generated is sent to the downstream steam heat user, and the cooled medium-temperature water outlet is mixed with the return water of the high-temperature hot water heat user and sent to the inlet of the water supply pump 16 to continue the heat production cycle.

[0023] 2. Control method for combustion, flue gas temperature and inner wall temperature of sulfur combustion furnace 1: The control targets are to meet the flue gas temperature required for maintaining normal combustion of sulfur and to meet the inner wall temperature of the sulfur combustion furnace 1 and the inner wall temperature of the soot settling tank 2 and the high-temperature SO2 flue 3 behind the furnace not lower than the acid dew point temperature of the SO2 flue gas. The air volume of the blower 21 is adjusted according to the set fluctuation range of the operating temperature of the exhaust gas temperature sensor 17 of the combustion furnace. When the operating temperature of the exhaust gas temperature sensor 17 rises to the upper limit of the set fluctuation range, the frequency converter or the air inlet guide is used to adjust the air volume of the blower 21. The blades increase the flow rate of the air supply fan 21. Conversely, when the operating temperature of the exhaust gas temperature sensor 17 drops to the lower limit of the set fluctuation range, the flow rate of the air supply fan 21 is reduced by the frequency converter or the air inlet guide vanes; the opening of the mixing damper 19 is adjusted according to the set fluctuation range of the operating temperature of the medium-temperature mixed gas sensor 18. When the operating temperature of the medium-temperature mixed gas sensor 18 rises to the upper limit of the set fluctuation range, the opening of the mixing damper 19 is closed. Conversely, when the operating temperature of the medium-temperature mixed gas sensor 18 drops to the lower limit of the set fluctuation range, the opening of the mixing damper 19 is opened.

[0024] 3. Control method of the water supply temperature and heat production of the micro high-temperature waste heat hot water boiler 10: Taking the water supply temperature of downstream high-temperature hot water heat users or the steam supply pressure requirements of steam heat users as the control target, wherein the opening of the electric regulating valve at the outlet of the water supply pump 16 is adjusted according to the set fluctuation range of the operating temperature of the water supply temperature sensor 15, thereby adjusting the water supply flow rate. When the operating temperature of the water supply temperature sensor 15 rises to the upper limit of the set fluctuation range, the flow rate of the water supply pump 16 is increased by increasing the opening of the electric regulating valve at the outlet of the water supply pump 16. Conversely, when the operating temperature of the water supply temperature sensor 15 drops to the lower limit of the set fluctuation range, the flow rate of the water supply pump 16 is reduced by closing the opening of the electric regulating valve at the outlet of the water supply pump 16.

[0025] 4. Control method for the steam production of the flash tank 23 and the heat supply to high-temperature hot water heat users: The priority control target is to first meet the steam demand of the downstream steam heat users of the secondary steam Q, and the remaining heat production is all transmitted to the downstream high-temperature hot water heat users as the operating principle. The opening of the water supply regulating valve 25 is adjusted according to the steam flow demand of the secondary steam Q. When the steam demand of the secondary steam Q increases, the opening of the water supply regulating valve 25 is closed. Conversely, when the steam demand of the secondary steam Q decreases, the opening of the water supply regulating valve 25 is opened. When the steam demand of the secondary steam Q decreases to 0, the water supply regulating valve 25 is fully opened and the bypass regulating valve 24 is closed. The opening of the bypass regulating valve 24 is adjusted according to the steam pressure demand of the secondary steam Q. When the steam operating pressure of the secondary steam Q is greater than the set pressure upper limit, the opening of the bypass regulating valve 24 is closed. Conversely, when the steam operating pressure of the secondary steam Q is less than the set pressure lower limit, the opening of the bypass regulating valve 24 is opened.

[0026] The working medium in the compressed working medium storage tank 22 is high-pressure nitrogen or compressed air.

[0027] The heat exchange sleeve 20 is made of carbon steel or boiler steel, and may or may not be provided with an insulation layer on the outside.

[0028] The ultra-large temperature difference heat exchanger 13 adopts a serpentine coil structure, a longitudinal tube bundle structure, a plate structure or a tube-sheet structure.

[0029] The ultra-large temperature difference heat exchanger 13 adopts a plain tube or finned tube structure.

[0030] The material of the ultra-large temperature difference heat exchanger 13 is carbon steel, ND steel, stainless steel 304 or stainless steel 316L.

[0031] The material of the water supply pump 16 is a high-temperature cast iron pump or a stainless steel water pump.

[0032] The beneficial effects of the present invention are as follows.

[0033] (1) In response to the problem that high-temperature SO2 flue gas is highly corrosive, this patent is based on the acid dew point control method to ensure that the temperature of the inner wall of the sulfur combustion furnace shell and the boiler exhaust pipe that are in contact with the flue gas is always maintained above the acid dew point, thereby ensuring that acid dew point corrosion will not occur and ensuring that the original equipment system will not have corrosion problems during the waste heat recovery process.

[0034] (2) This patent adopts a method of setting a sleeve on the outer shell of the sulfur combustion furnace and performing heat exchange through an annular area. The heat exchange medium is nitrogen or air, which has no corrosive problem. Therefore, commonly used boiler steel and other carbon steel, ND steel, stainless steel 304 or stainless steel 316L can be used as heat exchange pipe materials, thereby greatly reducing the processing difficulty and cost of the heat exchanger and the entire waste heat boiler, and solving the problem of recovering waste heat from the flue gas of the sulfur combustion furnace.

[0035] (3) The waste heat boiler can produce high-parameter waste hot water, and can also produce saturated wet steam of 0.1-0.6 MPa through a flash tank, which is more convenient for reuse in process production.

[0036] (4) By precisely controlling the most critical boiler water supply temperature to meet the parameter requirements of the external heat source; controlling the sleeve air inlet temperature and the combustion furnace exhaust temperature to avoid serious corrosion problems, the safe, stable and reliable operation of the equipment is ensured, the service life is increased, and the full-cycle operating cost is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a system diagram of the conventional production process for SO2 gas production from seawater bromine extraction. Figure 2 It is a system schematic diagram of the present invention.

[0038] Figure 1 、 2 The part numbers and names are as follows.

[0039] Sulfur combustion furnace 1, ash settling tank 2, high-temperature SO2 flue 3, water scrubber 4, clean SO2 flue gas pipe 5, Roots blower 6, water scrubber pump 7, original heat exchanger 8, absorption tower 9, micro high-temperature waste heat hot water boiler 10, inlet rectifier section 11, casing 12, ultra-large temperature difference heat exchanger 13, safety valve group 14, water supply temperature sensor 15, water feed pump 16, combustion furnace exhaust temperature sensor 17, medium-temperature mixed gas sensor 18, mixing damper 19, heat exchange sleeve 20, blower 21, compressed working fluid storage tank 22, flash tank 23, bypass regulating valve 24, water supply regulating valve 25, ambient air A, make-up water B, bromine-air mixture BrA, finished liquid BrH, high-temperature supply water G, high-temperature return water H, secondary steam Q, spray water R, sulfur S, high-temperature SO2 flue gas S1, clean SO2 flue gas S2, waste sulfuric acid liquid SH. DETAILED DESCRIPTION

[0040] Figure 1 This is a system diagram and example of a conventional production process for SO2 gas production from seawater bromine extraction. Figure 2 It is a system diagram and embodiment of the present invention.

[0041] The following is an example of a conventional production process for preparing SO2 gas from seawater bromine extraction. Figure 1 As shown. The conventional system includes a sulfur combustion furnace 1, a soot settling tank 2, a high-temperature SO2 flue 3, a water scrubber 4, a clean SO2 flue pipe 5, a Roots blower 6, a water scrubber 7, an original heat exchanger 8, an absorption tower 9 and its connecting pipes and components. The air inlet of the sulfur combustion furnace 1 is connected to the air outlet of the Roots blower 6. The sulfur combustion furnace 1 is also provided with a feed port for sulfur S. The air inlet of the Roots blower 6 is in communication with the ambient air A. The flue gas outlet of the sulfur combustion furnace 1 is connected to the inlet of the soot settling tank 2. The outlet of the soot settling tank 2 is connected to the flue gas inlet of the water scrubber 4 through the high-temperature flue 3 of the high-temperature SO2 flue gas S1. The flue gas outlet of the water scrubber 4 is the SO2 flue gas S2 of the clean SO2 flue gas, and its downstream is connected to the flue gas inlet of the absorption tower 9; the bottom acid outlet of the water scrubber 4 is connected to the inlet of the water scrubbing pump 7, and the outlet of the water scrubbing pump 7 is connected to the high-temperature side inlet of the original heat exchanger 8, and the high-temperature side outlet of the original heat exchanger 8 is connected to the spray device inlet of the water scrubber 4, and is connected to the discharge pipe of the waste sulfuric acid liquid SH and the water pipe of the make-up water B. The low-temperature side inlet and outlet of the original heat exchanger 8 are respectively connected to the heated water inlet and return water pipelines; the absorption tower 9 is also provided with an inlet for spray water R, an inlet for bromine and air mixture BrA, and an outlet for finished liquid BrH.

[0042] The specific embodiments of the present invention are as follows, see Figure 2A flash steam production system for a sulfur combustion furnace sleeve type waste heat boiler is composed of the original combustion furnace and SO2 flue gas water washing tower subsystem and the combustion furnace body heat extraction and flash steam production boiler subsystem and its connecting pipes and components. The original combustion furnace and SO2 flue gas water washing tower subsystem includes a sulfur combustion furnace 1, a soot settling tank 2, a high-temperature SO2 flue 3, a water washing tower 4, a clean SO2 flue gas pipe 5, a Roots blower 6, a water washing pump 7, an absorption tower 9 and its connecting pipes and components. It is characterized in that the combustion furnace body heat extraction The flash steam boiler subsystem includes a heat exchange sleeve 20, a micro high-temperature waste heat hot water boiler 10, a water feed pump 16, a flash tank 23, a blower 21, a compressed working medium gas storage tank 22, a mixing damper 19 and its connecting pipes and components, wherein the heat exchange sleeve 20 is arranged on the outside of the shell of the sulfur combustion furnace 1, and the closed annular space between the two is the area where the heat exchange working medium flows and exchanges heat, wherein the air inlet of the heat exchange sleeve 20 is arranged at one end of the smoke outlet of the sulfur combustion furnace 1, and the air outlet of the heat exchange sleeve 20 is arranged at the sulfur combustion furnace 1. One end of the air inlet of the sulfur combustion furnace 1; the air outlet of the heat exchange sleeve 20 is connected to the high-pressure inlet of the mixing damper 19 and the inlet of the inlet rectifier section 11 of the micro high-temperature waste heat hot water boiler 10, and the micro high-temperature waste heat hot water boiler 10 also includes a shell 12, an ultra-large temperature difference heat exchanger 13 and an outlet tapering section, the outlet of the medium-temperature heat exchange working medium of the outlet tapering section is connected to the low-pressure outlet of the mixing damper 19, the inlet of the blower 21 and the air outlet of the compressed working medium gas storage tank 22, and the air outlet of the blower 21 is connected to the air inlet of the heat exchange sleeve 20. The water inlet of the ultra-large temperature difference heat exchanger 13 is connected to the outlet of the water feed pump 16, the water outlet of the ultra-large temperature difference heat exchanger 13 is connected to the inlet of the water supply regulating valve 25 and the inlet of the bypass regulating valve 24, the outlet of the water supply regulating valve 25 is connected to the water supply pipe of the high-temperature water supply G, the outlet of the bypass regulating valve 24 is connected to the high-temperature water inlet of the flash tank 23, the steam outlet of the flash tank 23 is connected to the steam supply pipe of the secondary steam Q, and the medium-temperature water outlet of the flash tank 23 is connected to the inlet of the water feed pump 16 and the water pipe of the high-temperature return water H.

[0043] A safety valve group 14 and a water supply temperature sensor 15 are provided on the water outlet pipe section of the ultra-large temperature difference heat exchanger 13, a medium-temperature mixed gas sensor 18 is provided on the medium-temperature heat exchange working medium outlet pipe section of the micro high-temperature waste heat hot water boiler 10, and a combustion furnace exhaust temperature sensor 17 is provided on the high-temperature SO2 flue 3 at the flue gas outlet of the sulfur combustion furnace 1.

[0044] The operating temperature of the water supply temperature sensor 15 is controlled by the opening of the electric regulating valve at the outlet of the water supply pump 16; the lower limit temperature of the medium-temperature mixed gas sensor 18 is controlled by the opening of the mixing air door 19; the lower limit temperature of the combustion furnace exhaust temperature sensor 17 is controlled by the flow rate adjusted by the blower 21 through the frequency converter or the air inlet guide vane.

[0045] The working method of the flash steam generation system of the sulfur combustion furnace sleeve type waste heat boiler is as follows.

[0046] 1. The working process of the flash steam production system of the sleeve-type waste heat boiler of the sulfur combustion furnace is as follows: before starting the sulfur combustion furnace 1, the combustion furnace body heat extraction and flash steam production boiler subsystem are started first, wherein the blower 21 is started, the air supply valve of the compressed working medium gas storage tank 22 is opened, and the mixing damper 19 is opened; then the sulfur combustion furnace 1 and the original combustion furnace and SO2 flue gas water washing tower subsystem are started, at this time the blower 21 is started to send the heat exchange working medium into the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange sleeve 20, and the heat exchange working medium is heated and sent to ... working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange working medium is sent to the annular area between the outer shell of the sulfur combustion furnace 1 and the heat exchange The inlet rectifying section 11 of the micro high-temperature waste heat hot water boiler 10; at this time, the water supply pump 16 is started and the boiler feed water is sent to the ultra-large temperature difference heat exchanger 13 to exchange heat with the heat exchange medium on the other side. After the heat exchange medium is cooled, it returns to the inlet of the blower 21 to continue the circulation heat exchange; the high-temperature outlet water of the ultra-large temperature difference heat exchanger 13 is divided into two paths, one of which is sent to the downstream high-temperature hot water heat user, and the other is sent to the flash tank 23 for flash evaporation. The secondary steam generated is sent to the downstream steam heat user, and the cooled medium-temperature water outlet is mixed with the return water of the high-temperature hot water heat user and sent to the inlet of the water supply pump 16 to continue the heat production cycle.

[0047] 2. Control method for combustion, flue gas temperature and inner wall temperature of sulfur combustion furnace 1: The control targets are to meet the flue gas temperature required for maintaining normal combustion of sulfur and to meet the inner wall temperature of the sulfur combustion furnace 1 and the inner wall temperature of the soot settling tank 2 and the high-temperature SO2 flue 3 behind the furnace not lower than the acid dew point temperature of the SO2 flue gas. The air volume of the blower 21 is adjusted according to the set fluctuation range of the operating temperature of the exhaust gas temperature sensor 17 of the combustion furnace. When the operating temperature of the exhaust gas temperature sensor 17 rises to the upper limit of the set fluctuation range, the frequency converter or the air inlet guide is used to adjust the air volume of the blower 21. The blades increase the flow rate of the air supply fan 21. Conversely, when the operating temperature of the exhaust gas temperature sensor 17 drops to the lower limit of the set fluctuation range, the flow rate of the air supply fan 21 is reduced by the frequency converter or the air inlet guide vanes; the opening of the mixing damper 19 is adjusted according to the set fluctuation range of the operating temperature of the medium-temperature mixed gas sensor 18. When the operating temperature of the medium-temperature mixed gas sensor 18 rises to the upper limit of the set fluctuation range, the opening of the mixing damper 19 is closed. Conversely, when the operating temperature of the medium-temperature mixed gas sensor 18 drops to the lower limit of the set fluctuation range, the opening of the mixing damper 19 is opened.

[0048] 3. Control method of the water supply temperature and heat production of the micro high-temperature waste heat hot water boiler 10: Taking the water supply temperature of downstream high-temperature hot water heat users or the steam supply pressure requirements of steam heat users as the control target, wherein the opening of the electric regulating valve at the outlet of the water supply pump 16 is adjusted according to the set fluctuation range of the operating temperature of the water supply temperature sensor 15, thereby adjusting the water supply flow rate. When the operating temperature of the water supply temperature sensor 15 rises to the upper limit of the set fluctuation range, the flow rate of the water supply pump 16 is increased by increasing the opening of the electric regulating valve at the outlet of the water supply pump 16. Conversely, when the operating temperature of the water supply temperature sensor 15 drops to the lower limit of the set fluctuation range, the flow rate of the water supply pump 16 is reduced by closing the opening of the electric regulating valve at the outlet of the water supply pump 16.

[0049] 4. Control method for the steam production of the flash tank 23 and the heat supply to high-temperature hot water heat users: The priority control target is to first meet the steam demand of the downstream steam heat users of the secondary steam Q, and the remaining heat production is all transmitted to the downstream high-temperature hot water heat users as the operating principle. The opening of the water supply regulating valve 25 is adjusted according to the steam flow demand of the secondary steam Q. When the steam demand of the secondary steam Q increases, the opening of the water supply regulating valve 25 is closed. Conversely, when the steam demand of the secondary steam Q decreases, the opening of the water supply regulating valve 25 is opened. When the steam demand of the secondary steam Q decreases to 0, the water supply regulating valve 25 is fully opened and the bypass regulating valve 24 is closed. The opening of the bypass regulating valve 24 is adjusted according to the steam pressure demand of the secondary steam Q. When the steam operating pressure of the secondary steam Q is greater than the set pressure upper limit, the opening of the bypass regulating valve 24 is closed. Conversely, when the steam operating pressure of the secondary steam Q is less than the set pressure lower limit, the opening of the bypass regulating valve 24 is opened.

[0050] The working medium in the compressed working medium storage tank 22 is high-pressure nitrogen or compressed air.

[0051] The heat exchange sleeve 20 is made of carbon steel or boiler steel, and may or may not be provided with an insulation layer on the outside.

[0052] The ultra-large temperature difference heat exchanger 13 adopts a serpentine coil structure, a longitudinal tube bundle structure, a plate structure or a tube-sheet structure.

[0053] The ultra-large temperature difference heat exchanger 13 adopts a plain tube or finned tube structure.

[0054] The material of the ultra-large temperature difference heat exchanger 13 is carbon steel, ND steel, stainless steel 304 or stainless steel 316L.

[0055] The material of the water supply pump 16 is a high-temperature cast iron pump or a stainless steel water pump.

[0056] It should be noted that the present invention is based on key technologies such as the use of a sleeve outside the combustion furnace shell to extract heat and control the acid dew point to achieve waste heat recovery from high-temperature SO2 flue gas and high-temperature hot water flash steam production, and proposes a whole new set of high-temperature SO2 flue gas equipment and systems. According to this solution, there may be different specific implementation measures and specific implementation devices with different structures. The above specific implementation method is only one of the implementation types. Any other similar simple deformation implementation methods, such as simple addition, deletion, deformation, and change of relative position of internal components and interfaces, simple combination and adjustment of external pipelines and components, etc., all fall within the scope of protection of the present invention.

Claims

1. A flash steam production system for a sleeve-type waste heat boiler of a sulfur combustion furnace, comprising a primary combustion furnace and SO2 flue gas water washing tower subsystem and a combustion furnace body heat extraction and flash steam production boiler subsystem and its connecting pipes and components, wherein the primary combustion furnace and SO2 flue gas water washing tower subsystem comprises a sulfur combustion furnace (1), an ash settling tank (2), a high-temperature SO2 flue (3), a water washing tower (4), a clean SO2 flue gas pipe (5), a Roots blower (6), a water washing pump (7), an absorption tower (9) and its connecting pipes and components, and is characterized in that: The combustion furnace body heat extraction and flash steam production boiler subsystem comprises a heat exchange sleeve (20), a micro high-temperature waste heat hot water boiler (10), a water supply pump (16), a flash tank (23), a blower (21), a compressed working medium gas storage tank (22), a mixing damper (19) and its connecting pipes and components, wherein the heat exchange sleeve (20) is arranged on the outside of the shell of the sulfur combustion furnace (1), and the closed annular space between the two is the area where the heat exchange working medium flows and exchanges heat, wherein the air inlet of the heat exchange sleeve (20) is arranged at one end of the smoke outlet of the sulfur combustion furnace (1), and the air outlet of the heat exchange sleeve (20) is arranged at one end of the air inlet of the sulfur combustion furnace (1); the air outlet of the heat exchange sleeve (20) is connected to the mixing damper. The high-pressure inlet of the mixing damper (19) is connected to the inlet of the inlet rectifying section (11) of the micro high-temperature waste heat hot water boiler (10). The micro high-temperature waste heat hot water boiler (10) further includes a shell (12), an ultra-large temperature difference heat exchanger (13) and an outlet tapered section. The medium-temperature heat exchange medium outlet of the outlet tapered section is connected to the low-pressure outlet of the mixing damper (19), the inlet of the blower (21) and the air outlet of the compressed medium gas storage tank (22). The air outlet of the blower (21) is connected to the air inlet of the heat exchange sleeve (20); wherein the water inlet of the ultra-large temperature difference heat exchanger (13) is connected to the outlet of the water feed pump (16), and the water outlet of the ultra-large temperature difference heat exchanger (13) is connected to the inlet and the outlet of the water supply regulating valve (25). The inlet of the bypass regulating valve (24) is connected, the outlet of the water supply regulating valve (25) is connected to the water supply pipe of the high-temperature water supply (G), the outlet of the bypass regulating valve (24) is connected to the high-temperature water inlet of the flash tank (23), the steam outlet of the flash tank (23) is connected to the steam supply pipe of the secondary steam (Q), and the medium-temperature water outlet of the flash tank (23) is connected to the inlet of the water pump (16) and the water pipe of the high-temperature return water (H); the water outlet pipe section of the ultra-large temperature difference heat exchanger (13) is provided with a safety valve group (14) and a water supply temperature sensor (15), the medium-temperature heat exchange working medium outlet pipe section of the micro high-temperature waste heat hot water boiler (10) is provided with a medium-temperature mixed gas sensor (18), the sulfur combustion furnace (1 ) is provided on the high-temperature SO2 flue (3) at the flue gas outlet of the combustion furnace; the material of the super-large temperature difference heat exchanger (13) is carbon steel, ND steel, stainless steel 304 or stainless steel 316L; the combustion and flue gas temperature and inner wall temperature control method of the sulfur combustion furnace (1) are as follows: the flue gas temperature required for maintaining normal combustion of sulfur is satisfied, and the inner wall temperature of the sulfur combustion furnace (1) and the ash settling tank (2) behind the furnace and the inner wall temperature of the high-temperature SO2 flue (3) are not lower than the acid dew point temperature of the SO2 flue gas as the control target, wherein the air volume of the blower (21) is adjusted according to the set fluctuation range of the operating temperature of the combustion furnace exhaust temperature sensor (17).

2. A flash steam generation system for a sulfur combustion furnace sleeve type waste heat boiler according to claim 1, characterized in that The operating temperature of the water supply temperature sensor (15) is controlled by the opening of the electric regulating valve at the outlet of the water supply pump (16); the lower limit temperature of the medium-temperature mixed gas sensor (18) is controlled by the opening of the mixing air door (19); and the lower limit temperature of the combustion furnace exhaust gas temperature sensor (17) is controlled by the flow rate of the blower (21) adjusted by the frequency converter or the air inlet guide vane.

3. A flash steam generation system for a sulfur combustion furnace sleeve type waste heat boiler according to claim 2, characterized in that The working method of the flash steam generation system of the sulfur combustion furnace sleeve type waste heat boiler is as follows:

1. The working process of the flash steam production system of the sleeve-type waste heat boiler of the sulfur combustion furnace is as follows: before the sulfur combustion furnace (1) is started, the combustion furnace body heat extraction and flash steam production boiler subsystem are started first, wherein the blower (21) is started, the air supply valve of the compressed working medium gas storage tank (22) is opened, and the mixing damper (19) is opened; then the sulfur combustion furnace (1) and the original combustion furnace and SO2 flue gas water washing tower subsystem are started, at this time the blower (21) is started to send the heat exchange working medium into the annular area between the shell of the sulfur combustion furnace (1) and the heat exchange sleeve (20), and the heat exchange working medium is heated and sent to ... working medium. To the inlet rectifying section (11) of the micro high-temperature waste heat hot water boiler (10); at this time, the feed water pump (16) is started and the boiler feed water is sent to the ultra-large temperature difference heat exchanger (13) to exchange heat with the heat exchange medium on the other side. After the heat exchange medium is cooled, it returns to the inlet of the blower (21) to continue the heat exchange cycle; the high-temperature outlet water of the ultra-large temperature difference heat exchanger (13) is divided into two paths, one of which is sent to the downstream high-temperature hot water heat user, and the other is sent to the flash tank (23) for flash evaporation. The secondary steam generated is sent to the downstream steam heat user, and the cooled medium-temperature water outlet is mixed with the return water of the high-temperature hot water heat user and sent to the inlet of the feed water pump (16) to continue the heat generation cycle; 2. A method for controlling the combustion, flue gas temperature and inner wall temperature of a sulfur combustion furnace (1): The control targets are to meet the flue gas temperature required for maintaining normal combustion of sulfur, and to meet the inner wall temperature of the sulfur combustion furnace (1) and the inner wall temperature of the soot settling tank (2) and the high-temperature SO2 flue (3) behind the furnace not lower than the acid dew point temperature of the SO2 flue gas. The air volume of the blower (21) is adjusted according to the set fluctuation range of the operating temperature of the exhaust gas temperature sensor (17) of the combustion furnace. When the operating temperature of the exhaust gas temperature sensor (17) rises to the upper limit of the set fluctuation range, the blower (21) is increased by the frequency converter or the air inlet guide vane. The flow rate of the air supply fan (21) is increased, and when the operating temperature of the exhaust gas temperature sensor (17) drops to the lower limit of the set fluctuation range, the flow rate of the air supply fan (21) is reduced by the frequency converter or the air inlet guide vane; the opening of the mixing air door (19) is adjusted according to the set fluctuation range of the operating temperature of the medium-temperature mixed gas sensor (18); when the operating temperature of the medium-temperature mixed gas sensor (18) rises to the upper limit of the set fluctuation range, the opening of the mixing air door (19) is closed; when the operating temperature of the medium-temperature mixed gas sensor (18) drops to the lower limit of the set fluctuation range, the opening of the mixing air door (19) is increased; 3. A method for controlling the water supply temperature and heat production of a micro high-temperature waste heat hot water boiler (10): taking the water supply temperature of downstream high-temperature hot water users or the steam supply pressure of steam users as a control target, wherein the opening of the electric regulating valve at the outlet of the water supply pump (16) is adjusted according to the set fluctuation range of the operating temperature of the water supply temperature sensor (15), thereby adjusting the water supply flow rate. When the operating temperature of the water supply temperature sensor (15) rises to the upper limit of the set fluctuation range, the flow rate of the water supply pump (16) is increased by increasing the opening of the electric regulating valve at the outlet of the water supply pump (16). Conversely, when the operating temperature of the water supply temperature sensor (15) decreases to the lower limit of the set fluctuation range, the flow rate of the water supply pump (16) is reduced by decreasing the opening of the electric regulating valve at the outlet of the water supply pump (16); 4. Control method of the steam production of the flash tank (23) and the heat supply to the high-temperature hot water heat user: the priority control target is to first meet the steam demand of the downstream steam heat user of the secondary steam (Q), and the remaining heat production is all transmitted to the downstream high-temperature hot water heat user as the operating principle, wherein the opening of the water supply regulating valve (25) is adjusted according to the steam flow demand of the secondary steam (Q). When the steam demand of the secondary steam (Q) increases, the opening of the water supply regulating valve (25) is closed, and conversely, when the steam demand of the secondary steam (Q) decreases, the opening of the water supply regulating valve (25) is opened. The opening of the water supply regulating valve (25) is increased. When the steam demand of the secondary steam (Q) is reduced to 0, the water supply regulating valve (25) is fully opened and the bypass regulating valve (24) is closed. The opening of the bypass regulating valve (24) is adjusted according to the steam pressure demand of the secondary steam (Q). When the steam operating pressure of the secondary steam (Q) is greater than the set pressure upper limit, the opening of the bypass regulating valve (24) is reduced. Conversely, when the steam operating pressure of the secondary steam (Q) is less than the set pressure lower limit, the opening of the bypass regulating valve (24) is increased.

4. A flash steam generation system for a sulfur combustion furnace sleeve type waste heat boiler according to claim 1, characterized in that The working medium in the compressed working medium gas storage tank (22) is high-pressure nitrogen or compressed air.

5. A flash steam generation system for a sulfur combustion furnace sleeve type waste heat boiler according to claim 1, characterized in that The heat exchange sleeve (20) is made of carbon steel or boiler steel, and may or may not be provided with an insulation layer on the outside.

6. A flash steam generation system for a sulfur combustion furnace sleeve type waste heat boiler according to claim 1, characterized in that The ultra-large temperature difference heat exchanger (13) adopts a serpentine coil structure, a longitudinal tube bundle structure, a plate structure or a tube-sheet structure.

7. A flash steam generation system for a sulfur combustion furnace sleeve type waste heat boiler according to claim 1, characterized in that The ultra-large temperature difference heat exchanger (13) adopts a light tube or fin tube structure.

8. The flash steam generation system of a sulfur combustion furnace sleeve type waste heat boiler according to claim 1, characterized in that The water supply pump (16) is made of a high-temperature cast iron pump or a stainless steel water pump.

Images