Calcium-based dry desulfurization equipment and desulfurization process

Abstract

The invention discloses calcium-based dry desulfurization equipment and a desulfurization process, and relates to the technical field of industrial desulfurization, the calcium-based dry desulfurization equipment comprises a boiler flue, and the calcium-based dry desulfurization equipment further comprises a feeding system, a metering feeding system, a pneumatic conveying system and a desulfurization reaction system, the feeding system is used for storing calcium-based raw materials, and the metering feeding system is used for metering the raw materials; the metering feeding system is connected to the feeding system and used for quantitative feeding of calcium-based raw materials, the pneumatic conveying system comprises a heating device, a draught fan device and a conveying pipeline, the other end of the metering feeding system is connected to the conveying pipeline, the heating device and the draught fan device are sequentially arranged at one end of the conveying pipeline, and the desulfurization reaction system comprises an inner cylinder structure and an outer cylinder structure. The inner cylinder structure and the outer cylinder structure are coaxially arranged; according to the technical scheme, the problems that in the traditional power station boiler flue gas treatment process, the occupied area and resource investment are large, and intermediate products cannot be effectively utilized can be effectively solved, and the desulfurization efficiency and the desulfurization effect are effectively considered.

Description

Technical Field

[0001] The invention relates to the technical field of industrial desulfurization, and in particular to a calcium-based dry desulfurization device and a desulfurization process. Background Art

[0002] SO2 is a harmful air pollutant and the culprit for environmental problems such as acid rain. The SO2 emission from power station boiler flue gas must meet the emission requirements for boiler flue gas in GB13223-2011 "Emission Standards for Air Pollutants from Thermal Power Plants" and the "Opinions on Promoting the Implementation of Ultra-low Emissions in the Steel Industry" (Environmental Atmosphere

[2019] No. 35) jointly issued by the Ministry of Ecology and Environment and five other ministries and commissions. Therefore, the boiler flue gas needs to be equipped with a flue gas desulfurization device.

[0003] At present, the main boiler flue gas desulfurization processes include limestone / gypsum wet method, baking soda dry method and other processes; the limestone / gypsum wet method is widely used, the technology is mature, and the desulfurization by-products are easy to be recycled, but the system is relatively complex, and the land and investment are relatively large. It is more suitable for units with large flue gas volume and high SO2 content, but not suitable for power plant boiler flue gas treatment scenarios; compared with the limestone / gypsum wet desulfurization process, the baking soda dry desulfurization process system is relatively simple, and the land and investment are relatively small, but when it is used to treat power plant boiler flue gas, its desulfurization by-products are difficult to be recycled. Summary of the invention

[0004] The main purpose of the present invention is to propose a calcium-based dry desulfurization equipment and desulfurization process, aiming to solve the problem that the traditional equipment structure for desulfurization of power station boiler flue gas occupies a relatively large area and investment, and its desulfurization by-products are difficult to recycle.

[0005] To achieve the above object, the calcium-based dry desulfurization equipment proposed in the present invention includes a boiler flue, and the calcium-based dry desulfurization equipment also includes:

[0006] A feeding system for storing calcium-based raw materials;

[0007] A metering feeding system, connected to the feeding system, for quantitative delivery of the calcium-based raw material;

[0008] A pneumatic conveying system, comprising a heating device, a fan and a conveying pipeline, the other end of the metering feeding system is connected to the conveying pipeline, the heating device and the fan are sequentially arranged at one end of the conveying pipeline; and,

[0009] The desulfurization reaction system includes an inner cylinder structure and an outer cylinder structure, wherein the inner cylinder structure and the outer cylinder structure are coaxially arranged, and the upward end of the inner cylinder structure is connected to the inner cavity of the upper end of the outer cylinder structure, the other ends of the boiler flue and the conveying pipeline are connected to the downward end of the inner cylinder structure, and the inner wall of the inner cylinder structure is provided with swirl blades fixed thereto, which are used to disturb the gas inside the inner cylinder structure.

[0010] In one embodiment, the outer cylinder structure is provided with an outlet flue on a side wall near its lower end;

[0011] The desulfurization reaction system further includes a first bag filter, and one end of the outlet flue is connected to the first bag filter.

[0012] In one embodiment, a flue interface is provided on a downward end portion of the inner cylinder structure;

[0013] The pneumatic conveying system further comprises a spray gun, which is arranged inside one end of the conveying pipeline connected to the flue interface and is used to spray the calcium-based raw material into the inner cylinder structure;

[0014] The boiler flue is connected to the flue interface.

[0015] In one embodiment, the metering feeding system comprises:

[0016] A loss-in-weight scale, one end of which is connected to the feeding system, and a weighing sensor is provided at the bottom of the loss-in-weight scale;

[0017] A spiral feeding member, wherein the feeding port of the spiral feeding member is connected to the discharging port of the loss-in-weight scale; and

[0018] The injection device includes an injector and an air locking device, wherein the air locking device is arranged at the discharge port of the spiral feeding member, the injector is arranged on the conveying pipeline, and the air inlet of the injector is connected to the air outlet end of the heating device, one end of the conveying pipeline connected to the flue interface is connected to the air outlet of the injector, and the feed port of the injector is connected to the end of the air locking device away from the spiral feeding member.

[0019] In one embodiment, the metering feeding system further comprises:

[0020] an agitator, disposed inside the top of the hopper of the loss-in-weight scale, for refining the calcium-based raw material in the hopper of the loss-in-weight scale; and

[0021] The arch breaking device is arranged at the bottom of the hopper of the loss-in-weight scale and is used for continuous material discharge from the hopper of the loss-in-weight scale.

[0022] In one embodiment, the feeding system comprises:

[0023] A storage bin, wherein the top of the storage bin is provided with a second bag dust collector, an entry door and a gravity explosion-proof door, and the bottom of the storage bin is provided with a gasification plate and a rapper; and,

[0024] A discharge pipe is provided at the lower discharge port of the storage bin, the other end of the discharge pipe is connected to the loss-in-weight scale, and a manual gate valve, an electric gate valve and a star-shaped discharge valve are provided on the discharge pipe in sequence from top to bottom;

[0025] The storage bin is also provided with a material level detection device for obtaining the reserve of the calcium-based raw material in the storage bin.

[0026] The present invention also proposes a calcium-based dry desulfurization process, which is based on the above-mentioned calcium-based dry desulfurization equipment and includes:

[0027] Connect the flue gas to be treated to the desulfurization reaction system, and set the mass flow rate of the calcium-based raw material consumed in the desulfurization reaction according to the mass flow rate of SO2 in the flue gas to be treated;

[0028] The air is supplied and the carrier gas is heated through a pneumatic conveying system;

[0029] According to the set mass flow rate of calcium-based raw materials, the metering feeding system is controlled to quantitatively deliver the calcium-based raw materials to the pneumatic conveying system;

[0030] The calcium-based raw materials are delivered to the desulfurization reaction system through a pneumatic conveying system, so that the calcium-based raw materials and flue gas react in the inner cylinder structure and the outer cylinder structure.

[0031] In one embodiment, the supplying of air by a pneumatic conveying system and heating of the carrier gas comprises:

[0032] The fan is started to pressurize the gas in the conveying pipeline, so as to form an airflow in the conveying pipeline from the heating device to the inner cylinder structure;

[0033] Start the heating device and set its heating temperature to a preset heating temperature value range;

[0034] When the heating temperature of the heating device reaches a preset heating temperature value range, the calcium-based raw material is quantitatively added into the conveying pipeline by controlling the metering feeding system;

[0035] Wherein, the preset heating temperature value range is greater than the current dew point temperature of the air.

[0036] In one embodiment, the step of delivering the calcium-based raw material into the desulfurization reaction system through a pneumatic conveying system so that the calcium-based raw material and the flue gas react in the inner cylinder structure and the outer cylinder structure comprises:

[0037] When the fan is working, the spray gun at the connection between the conveying pipeline and the inner cylinder structure is started synchronously;

[0038] The calcium-based raw material is sprayed out through a spray gun, and under the action of the swirl blade, the calcium-based raw material and the flue gas to be treated are fully mixed;

[0039] The mixed flue gas forms a baffled reaction gas between the inner tube structure and the outer tube structure, and the flow rate of the baffled reaction gas is controlled so that the reaction time between the inner tube structure and the outer tube structure is not less than five seconds.

[0040] In one embodiment, the flue gas to be treated is connected to the desulfurization reaction system, and the mass flow rate of the calcium-based raw material consumed in the desulfurization reaction is set according to the mass flow rate of SO2 in the flue gas to be treated:

[0041] The flue gas to be treated is power station boiler flue gas, and the SO2 concentration in the power station boiler flue gas is less than or equal to 200 mg / Nm 3 , CO2 volume fraction is less than 30%, and the temperature is between 140℃ and 160℃;

[0042] The purity of the calcium-based raw material is greater than or equal to 85%, the moisture content is less than or equal to 2%, the particle size requirement is 325 mesh screening rate is greater than or equal to 85%, and the specific surface area is greater than or equal to 40m 2 / g, and the bulk density is between 0.4g / L and 0.65g / L.

[0043] The technical solution of the present invention is aimed at treating the flue gas of power station boilers. Compared with the wet desulfurization process of limestone gypsum, the present invention is a dry desulfurization process with a short process flow, a simple system, and relatively more economical land investment. At the same time, in this solution, calcium-based raw materials are used as raw materials for desulfurization reaction. Through the optimization of relevant structures and processes, the resource utilization problem of desulfurization by-products can be solved, and at the same time, the whole equipment takes into account good reaction efficiency and reaction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0045] Figure 1 A schematic structural diagram of an embodiment of a calcium-based dry desulfurization device provided by the present invention;

[0046] Figure 2 for Figure 1 Schematic diagram of the structure of the desulfurization reaction system in the medium calcium-based dry desulfurization equipment;

[0047] Figure 3 for Figure 1 Schematic diagram of the structure of the swirl blades in the medium calcium-based dry desulfurization equipment;

[0048] Figure 4 For application Figure 1 Process flow chart of medium calcium-based dry desulfurization equipment;

[0049] Figure 5 for Figure 4 The specific process flow chart of "supplying air and heating the carrier gas through a pneumatic conveying system";

[0050] Figure 6 for Figure 4 The specific process flow chart of "sending the calcium-based raw materials into the desulfurization reaction system through the pneumatic conveying system, so that the calcium-based raw materials and flue gas react in the inner cylinder structure and the outer cylinder structure".

[0051] Description of Figure Numbers:

[0052] 100. Calcium-based dry desulfurization equipment; 101. Gravity explosion-proof door; 102. Second bag filter; 103. Storage bin; 104. Vibrator; 105. Gasification plate; 106. Manual gate valve; 107. Electric gate valve; 108. Star discharge valve; 109. Discharge pipe; 110. Fan parts; 11. Heating device; 112. Agitator; 113. Loss-in-weight scale; 114. Arch breaking device; 115. Weighing sensor; 116. Screw feeder; 117. Air lock device; 11 8. Connecting pipe; 119. Ejector; 120. Delivery pipeline; 121. Spray gun; 122. Flue interface; 123. Desulfurization reaction system; 124. Exit flue; 125. First bag filter; 201. Swirl blade; 202. Inner tube structure; 203. Outer tube structure; 204. Inner tube support; 205. Outer tube top plate; 206. Exhaust flue; 301. Outer ring; 302. First guide vane; 303. Inner ring; 304. Second guide vane; 305. Center tube.

[0053] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0056] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0057] SO2 is a harmful air pollutant and the culprit for environmental problems such as acid rain. The SO2 emission from power station boiler flue gas must meet the emission requirements for boiler flue gas in GB13223-2011 "Emission Standards for Air Pollutants from Thermal Power Plants" and the "Opinions on Promoting the Implementation of Ultra-low Emissions in the Steel Industry" (Environmental Atmosphere

[2019] No. 35) jointly issued by the Ministry of Ecology and Environment and five other ministries and commissions. Therefore, the boiler flue gas needs to be equipped with a flue gas desulfurization device.

[0058] At present, the main boiler flue gas desulfurization processes include limestone / gypsum wet method, baking soda dry method and other processes; the limestone / gypsum wet method is widely used, the technology is mature, and the desulfurization by-products are easy to be recycled, but the system is relatively complex, and the land and investment are relatively large. It is more suitable for units with large flue gas volume and high SO2 content, but not suitable for power plant boiler flue gas treatment scenarios; compared with the limestone / gypsum wet desulfurization process, the baking soda dry desulfurization process system is relatively simple, and the land and investment are relatively small, but when it is used to treat power plant boiler flue gas, its desulfurization by-products are difficult to be recycled.

[0059] The present invention provides a calcium-based dry desulfurization device 100 .

[0060] See also Figures 1 to 3In one embodiment of the present invention, the calcium-based dry desulfurization equipment 100 uses a highly active calcium-based desulfurizer as a calcium-based raw material for the desulfurization reaction. In this embodiment, highly active Ca(OH)2 powder is used as a calcium-based raw material for the reaction. The highly active Ca(OH)2 powder is stored in a feeding system. In the actual production process, the highly active Ca(OH)2 powder is quantitatively supplied by a metering feeding system. In the entire production system, air is mainly used as a carrier to transport the highly active Ca(OH)2 powder. One end of the metering feeding system is connected to a conveying pipeline 120 in a pneumatic conveying system. During the operation of the pneumatic conveying system, the highly active Ca(OH)2 powder discharged from the metering feeding system can be brought into the desulfurization reaction system 123 to mix with the flue gas to be treated. The conveying pipeline 120 has a certain extension length. In the traditional process of supplying air through the conveying pipeline 120, the moisture in the air during the conveying of calcium-based raw materials can easily cause the highly active Ca(OH)2 powder to adhere to the inner wall of the conveying pipeline 120, thereby causing the conveying pipeline 120 to be blocked. Taking the above problems into consideration, in this embodiment, a heating device 11 is provided on the side of the conveying pipeline 120 corresponding to the fan component 110. The heating device 11 can heat the carrier gas in the conveying pipeline 120, so that the carrier gas temperature is higher than the dew point temperature of the air, thereby avoiding condensation of water vapor in the carrier gas in the pipeline, and preventing the powdered calcium-based raw materials from absorbing moisture and causing pipeline blockage, so that the entire conveying pipeline 120 can maintain a stable and unobstructed feeding state. Among them, considering that the pipeline has a certain extension length, in order to further ensure the dryness inside the conveying pipeline 120, an insulation layer and heating are provided on the outer wall of the conveying pipeline 120, and the heating temperature of the heating device 11 is controlled in real time during the feeding process, so as to ensure the dryness inside the entire conveying pipeline 120. The fan part 110 adopts a Roots blower, which can pressurize the air carrier gas in the conveying pipeline 120 during operation, so that the carrier gas flows into the desulfurization reaction system 123 after being heated by the heating device 11. In this process, the end of the metering feeding system is connected to the part of the conveying pipeline 120 between the heating device 11 and the desulfurization reaction system 123, and the hot air in the conveying pipeline 120 can bring the highly active Ca(OH)2 powder into the desulfurization reaction system 123 to mix and react with the flue gas to be treated.Among them, in order to increase the reaction effect between the flue gas to be treated and the calcium-based raw material, in this embodiment, the desulfurization reaction system 123 is also set as a double-layer reaction structure. Specifically, the outer cylinder structure 203 is coaxially sleeved on the outside of the inner cylinder structure 202, and the inner cylinder structure 202 is fixedly installed by the inner cylinder support 204 on the inner wall of the outer cylinder structure 203. The upper end of the outer cylinder structure 203 is closed by the outer cylinder top plate 205, and the upper end of the inner cylinder structure 202 is open and communicated with the inner cavity of the upper end of the outer cylinder structure 203. A flue interface 122 is provided on the lower end of the inner cylinder structure 202. When the flue gas is treated, the boiler flue and one end of the conveying pipeline 120 are connected to the flue interface 122, and the outlet flue 124 of the entire desulfurization reaction system 123 is arranged on the side wall of the lower end of the outer cylinder structure 203, and is connected to the subsequent gas treatment device through the exhaust flue 206. It can be imagined that, with such a configuration, the reaction gas formed by the flue gas to be treated and the calcium-based raw material first moves from bottom to top in the inner cylinder structure 202, then flows into the outer cylinder structure 203, and moves from the upper end of the outer cylinder structure 203 to its lower end, thereby forming a deflection. The setting of the above movement path can increase the reaction time between the flue gas to be treated and the calcium-based raw material, thereby effectively enhancing its reaction efficiency and reaction effect, and a swirl blade 201 is welded on the inner wall of the inner cylinder. In the process of the mixed gas moving from bottom to top in the inner cylinder structure 202, the swirl blade 201 can disturb the gas, thereby enhancing the mixing effect between the flue gas to be treated and the calcium-based raw material. The products finally formed by the reaction flue gas discharged from the outlet flue 124 through the exhaust flue 206 are mainly CaCO3 / Ca(OH)2 / CaSO4, etc. The above reaction products can be reused as limestone / gypsum wet desulfurization agents. Therefore, compared with traditional dry desulfurization equipment, the scheme in this embodiment is not only extremely efficient, but also can replace the baking soda dry desulfurization process, solving the problem that baking soda desulfurization ash is difficult to recycle.

[0061] Among them, in order to further ensure the conveying effect of the pneumatic conveying system on the powdered calcium-based raw materials, a spray gun 121 is connected to one end of the conveying pipeline 120 connected to the flue interface 122, and the spray gun 121 is inserted into the flue in a sleeve connection mode, one end of the sleeve is welded to the flue wall plate, and the other end is welded to the flange. After the spray gun 121 is inserted into the sleeve, it extends into the flue, and the tail welding flange of the spray gun 121 is connected and sealed with the sleeve flange. Through the above structural setting, in the process of feeding, through the cooperation of the fan component 110 and the spray gun 121, the movement effect of the powdered calcium-based raw materials in the conveying pipeline 120 can be better improved, thereby realizing efficient mixing of the flue gas to be treated and the calcium-based raw materials in the inner cylinder structure 202.

[0062] Among them, it can be imagined that the specific extension length and bending structure characteristics of the conveying pipeline 120 need to be determined according to the actual production structure. As for the existing desulfurization process, the limestone / gypsum wet method is widely used, but its system is relatively complex, and the land occupation and investment are relatively large. Compared with the limestone / gypsum wet desulfurization process, the baking soda dry desulfurization process system is relatively simple, and the land occupation and investment are relatively small. However, in the above production structure, the extension length of the conveying pipeline 120 is at least several meters or more than ten meters. Considering the convenience of installation and maintenance, in this embodiment, the conveying pipeline is specifically set to a plurality of detachable connection structures. In order to minimize the resistance during the feeding process of the entire conveying pipeline 120, the bending radius of the bending joint structure in the plurality of the connection structures is at least greater than ten times its outer diameter, and a blowing pipe is provided at the bending joint for blowing gas to blow away the blockage at the bend of the conveying pipeline 120. It can be imagined that the blown gas needs to be clean and dry gas.

[0063] In addition, in the above embodiment, a swirl blade 201 is provided on the inner wall of the inner cylinder structure 202 to disturb the airflow from bottom to top in the inner cylinder structure 202. The swirl blade 201 is fixedly installed on the inner side of the inner cylinder structure 202 near its lower end by welding, so that when the flue gas to be treated and the calcium-based raw material are discharged from the flue interface 122 into the inner cavity at the lower end of the inner cylinder structure 202, the formed rising airflow can be quickly disturbed, so that the flue gas and the reactants can be mixed as quickly as possible. Figure 2 and Figure 3As shown, the structure of the swirl blade 201 specifically includes two ring portions, wherein the inner ring portion 303 is coaxially arranged with the outer ring portion 301 corresponding to the inner side of the outer ring portion 301, and the outer ring portion 301 is a specific installation structure. During installation, the outer ring portion 301 and the inner wall of the inner cylinder structure 202 form an installation relationship by welding, and a plurality of first guide vanes 302 are provided between the inner ring portion 303 and the outer ring portion 301, and the plurality of first guide vanes 302 are all installed between the outer ring portion 301 and the inner ring portion 303 in an inclined state. In addition, a central tube 305 is provided at the center position of the inner ring 303 along its axial direction, and a plurality of second guide vanes 304 are provided between the central tube 305 and the inner ring 303. It should be noted that the plurality of second guide vanes 304 are also arranged in an inclined shape, and the inclination direction is opposite to that of the first guide vane 302. It can be imagined that when the gas flows from bottom to top, when the airflow passes through the inner ring 303, the plurality of second guide vanes 304 will form a swirl in the same direction of the airflow, and when the airflow passes through the plurality of first guide vanes 302, a swirl opposite to the above-mentioned swirl will be formed, and the two airflows will convect with each other in the inner cylinder structure 202, thereby further improving the mixing reaction effect between the flue gas to be treated and the calcium-based raw material. In addition, in order not to affect the upward movement of the airflow, the minimum inclination angle formed by the first guide vane 302 and the second guide vane 304 and the axis in the vertical direction should be less than 30 degrees.

[0064] The gases after the mixed reaction need to be uniformly collected and processed before they can be discharged, so a first bag filter 125 is connected to one end of the outer side of the outlet flue 124, wherein the flue gas after the desulfurization reactor 123 enters the first bag filter 125, and the desulfurization ash formed is discharged through the bag filter hopper, and the desulfurization ash can be used as a limestone / gypsum wet desulfurization agent, thereby forming a secondary utilization of the output.

[0065] The calcium-based dry desulfurization equipment 100 has the characteristics of continuous operation in the actual production process, wherein the metering feeding system needs to meet the demand for continuous quantitative discharge of the calcium-based raw materials. In this embodiment, the metering feeding system is mainly composed of a weight loss scale 113, a spiral feeder and an injection device, wherein the material discharged from the feeding system to the hopper of the weight loss scale 113 is measured by the weighing sensor 115 arranged on its lower end. The calcium-based raw materials in the weight loss scale 113 continuously flow into the spiral feeder, and the spiral feeder is continuously fed. The motor of the spiral feeder 116 is a variable frequency speed regulating motor, and the frequency setting value of the inverter is logically linked with the amount of SO2 removed to realize automatic adjustment of the discharge amount with the operating load. The material in the screw feeder 116 enters the mixing chamber of the ejector 119 through the air lock device 117 and the feed port of the ejector 119, and the part of the conveying pipeline 120 connected to the air outlet end of the heating device 11 is connected to the air inlet end of the ejector 119, so that the calcium-based raw material discharged from the feed port of the ejector 119 is sucked into the mixing chamber and sent into the conveying pipeline 120 from the air outlet end of the ejector 119. In this process, in order to ensure that the calcium-based raw material enters the mixing chamber better from the feed port of the ejector 119, a connecting pipe 118 is arranged between the unloading chute between the air lock device 117 and the ejector 119 and the air inlet pipeline of the ejector 119. When the carrier gas passes through the air inlet of the ejector 119 and the connecting pipe 118, negative pressure can be better applied to the throat at the feed port of the ejector 119, so that the calcium-based raw material can be better sucked into the mixing chamber.

[0066] In order to ensure the continuity and stability of the material discharge of the weight loss scale 113, the weight loss scale 113 is also provided with a stirrer 112 and an arch breaking device 114. Specifically, the stirrer 112 is arranged on the inner side of the top of the hopper of the weight loss scale 113, and is used to refine the calcium-based raw material in the hopper of the weight loss scale 113, so as to ensure that the calcium-based raw material powder in the hopper of the weight loss scale 113 is in a flowing state. The arch breaking device 114 is arranged at the bottom of the hopper of the weight loss scale 113, which can ensure the unobstructed discharge port of the hopper of the weight loss scale 113, so as to ensure the continuity and stability of the material discharge.

[0067] The feeding system mainly includes a storage bin 103 and a discharge pipe 109, wherein the storage bin 103 is configured as a cylinder with a flush top and a conical bottom. In addition, its maximum storage capacity is set according to three days' usage under maximum load. A second bag dust collector 102, a manhole door and a gravity explosion-proof door 101 are installed on the top of the silo. The second bag dust collector 102 is put into use when high-activity Ca(OH)2 powder is loaded. When the pressure in the silo exceeds the counterweight pressure of the gravity explosion-proof door 101, the gravity explosion-proof door 101 is opened; the high-activity Ca(OH)2 powder silo is provided with high and low level switches to monitor the material level in the silo, and a gasification plate 105 and a vibrator 104 are installed at the bottom of the silo to prevent powder blockage. The fluidizing air of the gasification plate 105 needs to use a dry and clean air source; the silo outlet is connected to the discharge pipe 109, and the discharge pipe 109 is equipped with a manual gate valve 106, an electric gate valve 107 and a star-shaped discharge valve 108 from top to bottom to control the discharge of materials.

[0068] It is conceivable that the above-mentioned feeding system can be set in corresponding quantity according to the actual production situation. When the number of the silos increases, the number of branches of the conveying pipeline 120 can be increased accordingly, so as to meet higher production efficiency requirements.

[0069] The present invention also discloses a dry desulfurization process, please refer to Figures 1 to 6 The dry desulfurization process is applied to the calcium-based dry desulfurization equipment 100. The specific structure of the calcium-based dry desulfurization equipment 100 refers to the above embodiment. Since the dry desulfurization process is based on the calcium-based dry desulfurization equipment 100, it should have at least all the beneficial effects of the calcium-based dry desulfurization equipment 100, which will not be described one by one here. Among them, the calcium-based dry desulfurization process includes:

[0070] Connect the flue gas to be treated to the desulfurization reaction system 123, and set the mass flow rate of the calcium-based raw material consumed in the desulfurization reaction according to the mass flow rate of SO2 in the flue gas to be treated;

[0071] This desulfurization process is mainly aimed at power station boiler flue gas, the SO2 concentration in the power station boiler flue gas is less than or equal to 200mg / Nm 3 , CO2 volume fraction is less than 30%, temperature is between 140℃ and 160℃, and its sulfur content is relatively low compared with traditional industrial boiler flue gas, so it can use a relatively small unit structure for flue gas desulfurization, and can achieve resource utilization of by-products. Among them, the purity of the calcium-based raw material is greater than or equal to 85%, the moisture content is less than or equal to 2%, the particle size requirement is 325 mesh screening rate is greater than or equal to 85%, and the specific surface area is greater than or equal to 40m 2 / g, and the bulk density is between 0.4g / L and 0.65g / L. Before actual production, the mass flow rate of SO2 in the flue gas of the power plant boiler needs to be detected, and the mass flow rate of the calcium-based raw material consumed in the desulfurization reaction is set according to the mass flow rate of SO2 in the flue gas to be treated, wherein the mass flow rate ratio of the calcium-based raw material to the SO2 in the flue gas to be treated is between 5 and 10.

[0072] The air is supplied and the carrier gas is heated through a pneumatic conveying system;

[0073] Before actually feeding the material, the pneumatic conveying system needs to be turned on in advance and the conveying pipeline 120 needs to be heated in advance, so as to ensure the dryness of the conveying pipeline 120 as much as possible.

[0074] According to the set mass flow rate of calcium-based raw materials, the metering feeding system is controlled to quantitatively deliver the calcium-based raw materials to the pneumatic conveying system;

[0075] After the conveying pipeline 120 is preheated, the feeding system unloads the material and quantitatively supplies the calcium-based raw material through the loss-in-weight scale 113 and the screw feeder 116 connected thereto, thereby delivering the calcium-based raw material to the conveying pipeline 120 and mixing it with the heated carrier gas. The high-temperature carrier gas in the pneumatic conveying system can ensure the dryness of the inside of the conveying pipeline 120, thereby avoiding the problem of powdered calcium-based raw material sticking to the inner wall of the conveying pipeline 120, thereby affecting the continuous quantitative supply of the calcium-based raw material.

[0076] The calcium-based raw material is delivered to the desulfurization reaction system 123 through a pneumatic conveying system, so that the calcium-based raw material and the flue gas react in the inner cylinder structure 202 and the outer cylinder structure 203;

[0077] When the calcium-based raw material is mixed with the high-temperature carrier gas at the injector 119, the powdered calcium-based raw material in the conveying pipeline 120 will be continuously supplied to the desulfurization system due to the action of the fan 110 and the spray gun 121, thereby prompting the power station boiler flue gas and the calcium-based raw material to mix and react in the inner tube structure 202 and the outer tube structure 203, thereby removing SO2 in the flue gas.

[0078] It should be noted that the above-mentioned desulfurization process and desulfurization equipment in this scheme are set up for the flue gas of power plant boilers. The content of the main components in the flue gas of the power plant is as shown in the relevant content published above. The calcium-based raw materials are used for desulfurization in this scheme, which can not only use a smaller equipment composition structure similar to that used in the baking soda dry desulfurization process, but also solve the problem of difficulty in resource utilization of baking soda desulfurization ash. In the specific structure, it can also avoid the desulfurizer clogging the delivery pipeline 120, and has a good performance in improving the efficiency of SO2 removal reaction.

[0079] The method of supplying air and heating the carrier gas by the pneumatic conveying system comprises:

[0080] The fan element 110 is started to pressurize the gas in the delivery pipeline 120, so as to form an airflow in the delivery pipeline 120 from the heating device 11 to the inner cylinder structure 303;

[0081] The fan 110 is started to pressurize the gas in the delivery pipeline 120, so as to form an airflow in the delivery pipeline 120 from the heating device 11 to the inner cylinder structure 202. When the heating temperature of the heating device 11 reaches a preset heating temperature value range, a relatively dry air supply environment can be formed in the delivery pipeline 120.

[0082] Start the heating device and set its heating temperature to a preset heating temperature value range;

[0083] The heating device 11 is started to heat the air in the conveying pipeline 120, so that the carrier gas temperature is higher than the dew point temperature of the air, to avoid water vapor condensation of the carrier gas in the pipeline, to keep the inner wall of the conveying pipeline 120 dry, to avoid moisture absorption and clogging of the powdered calcium-based raw materials in the pipeline. The heating temperature of the heating device 11 can be preset. After reaching the corresponding temperature, the heating device 11 can maintain the current output state, so as to ensure the dryness of the material in the conveying pipeline 120. It should be noted that for conveying pipelines of different lengths and external conditions, the specific preset temperature value range needs to be calculated and determined according to the actual situation. For example, when the pipeline is long, the heating device 11 may need to be set at 100°C above the air dew point temperature. When the pipeline is short, the actual heating temperature can be set at 50°C above the air dew point temperature.

[0084] When the heating temperature of the heating device reaches a preset heating temperature value range, the calcium-based raw material is quantitatively added into the conveying pipeline by controlling the metering feeding system;

[0085] When the carrier gas temperature is higher than the dew point temperature of the air, the conveying pipeline 120 is in a relatively dry state. At this time, the calcium-based raw material can be quantitatively added to the conveying pipeline 120 by controlling the metering feeding system. Since the water content of the calcium-based raw material is low, the powdered calcium-based raw material can move with the dry carrier gas to the desulfurization reaction system 123 for desulfurization reaction.

[0086] The preset heating temperature value range is above the air dew point temperature. During the actual production process, the actual heating temperature reaches above the air dew point temperature, which can avoid condensation of water vapor in the air, thereby allowing the conveying pipeline 120 to maintain a continuous and stable feeding state.

[0087] The step of delivering the calcium-based raw material into the desulfurization reaction system 123 through the pneumatic conveying system so that the calcium-based raw material and the flue gas react in the inner cylinder structure 202 and the outer cylinder structure 203 includes:

[0088] When the fan element 110 is working, the spray gun 121 at the connection between the delivery pipeline 120 and the inner cylinder structure 202 is started synchronously;

[0089] In order to ensure the material supply effect in the conveying pipeline 120, the fan component 110 and the spray gun 121 are used to operate simultaneously. The fan component 110 is arranged at the end of the conveying pipeline 120 away from the desulfurization reaction system 123, and is used to pressurize the air, thereby prompting the air to move toward the desulfurization reaction system 123. The spray gun 121 is arranged at the end of the conveying pipeline 120 corresponding to the desulfurization reaction system 123, which can prompt the calcium-based raw material to be discharged upward from the end of the conveying pipeline 120 at a certain speed, thereby forming an upward airflow and mixing with the power station boiler flue gas in the inner tube structure 202 and the outer tube structure 203.

[0090] The calcium-based raw material is sprayed out through the spray gun 121, and under the action of the swirl blade 201, the calcium-based raw material and the flue gas to be treated are fully mixed;

[0091] As mentioned above, the swirl blade 201 is divided into an inner ring portion 303 and an outer ring portion 301. When the gas moves upward from the bottom of the inner cylinder structure 202, two airflows with opposite rotation directions can be formed in the two ring portions. The collision of the two airflows can effectively promote the mixing effect between the power station boiler flue gas and the powdered calcium-based raw material, which is more conducive to the desulfurization reaction.

[0092] The mixed flue gas forms a baffled reaction gas between the inner cylinder structure 202 and the outer cylinder structure 203, and the flow rate of the baffled reaction gas is controlled so that the reaction time between the inner cylinder structure 202 and the outer cylinder structure 203 is not less than four seconds.

[0093] In order to further improve the desulfurization reaction effect in the inner cylinder structure 202 and the outer cylinder structure 203, the inner cylinder structure 202 and the outer cylinder structure 203 are arranged to enable the reaction gas to form a baffle effect, thereby effectively increasing the mixing reaction time of the reaction gas in the inner cylinder structure 202 and the outer cylinder structure 203, thereby improving the desulfurization reaction effect as much as possible.

[0094] Among them, the flow rate of the gas in the inner cylinder structure 202 and the outer cylinder structure 203 is controlled between 15m / s and 18m / s, and at the same time, it is necessary to ensure that the total reaction mixing time of the mixed reaction flue gas formed in the inner cylinder structure 202 and the outer cylinder structure 203 is not less than four seconds. The above time control can be realized by designing the corresponding inner cylinder structure 202 and the outer cylinder structure 203 according to the actual gas flow rate. At the same time, considering the reaction efficiency, it is preferred to control the total reaction time of the reaction mixed gas in the inner cylinder structure 202 and the outer cylinder structure 203 between four seconds and five seconds. The above structure and process are mainly aimed at the mixed reaction effect of power station boiler flue gas and powdered calcium-based raw materials. Compared with the traditional structure and process, it can take into account better desulfurization reaction effect and reaction efficiency.

[0095] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A calcium-based dry desulfurization equipment, comprising a boiler flue, characterized in that: include: A feeding system for storing calcium-based raw materials; A metering feeding system, connected to the feeding system, for quantitative delivery of the calcium-based raw material; A pneumatic conveying system, comprising a heating device, a fan and a conveying pipeline, the other end of the metering feeding system is connected to the conveying pipeline, the heating device and the fan are sequentially arranged at one end of the conveying pipeline; and, The desulfurization reaction system includes an inner cylinder structure and an outer cylinder structure, wherein the inner cylinder structure and the outer cylinder structure are coaxially arranged, and the upward end of the inner cylinder structure is connected to the inner cavity of the upper end of the outer cylinder structure, the other ends of the boiler flue and the conveying pipeline are connected to the downward end of the inner cylinder structure, and the inner wall of the inner cylinder structure is provided with swirl blades fixed thereto, which are used to disturb the gas inside the inner cylinder structure.

2. The calcium-based dry desulfurization equipment according to claim 1, characterized in that: The outer cylinder structure is provided with an outlet flue on the side wall near the lower end thereof; The desulfurization reaction system further includes a first bag filter, and one end of the outlet flue is connected to the first bag filter.

3. The calcium-based dry desulfurization equipment according to claim 1, characterized in that: A flue interface is provided on a downward end portion of the inner cylinder structure; The pneumatic conveying system further comprises a spray gun, which is arranged inside one end of the conveying pipeline connected to the flue interface and is used to spray the calcium-based raw material into the inner cylinder structure; The boiler flue is connected to the flue interface.

4. The calcium-based dry desulfurization equipment according to claim 1, characterized in that: The metering feeding system comprises: A loss-in-weight scale, one end of which is connected to the feeding system, and a weighing sensor is provided at the bottom of the loss-in-weight scale; A spiral feeding member, wherein the feeding port of the spiral feeding member is connected to the discharging port of the loss-in-weight scale; and The injection device includes an injector and an air locking device, wherein the air locking device is arranged at the discharge port of the spiral feeding member, the injector is arranged on the conveying pipeline, and the air inlet of the injector is connected to the air outlet end of the heating device, one end of the conveying pipeline connected to the flue interface is connected to the air outlet of the injector, and the feed port of the injector is connected to the end of the air locking device away from the spiral feeding member.

5. The calcium-based dry desulfurization equipment according to claim 4, characterized in that: The metering feeding system also includes: an agitator, disposed inside the top of the hopper of the loss-in-weight scale, for refining the calcium-based raw material in the hopper of the loss-in-weight scale; and The arch breaking device is arranged at the bottom of the hopper of the loss-in-weight scale and is used for continuous material discharge from the hopper of the loss-in-weight scale.

6. The calcium-based dry desulfurization equipment according to claim 4, characterized in that: The feeding system comprises: A storage bin, wherein the top of the storage bin is provided with a second bag dust collector, an entry door and a gravity explosion-proof door, and the bottom of the storage bin is provided with a gasification plate and a rapper; and, A discharge pipe is provided at the lower discharge port of the storage bin, the other end of the discharge pipe is connected to the loss-in-weight scale, and a manual gate valve, an electric gate valve and a star-shaped discharge valve are provided on the discharge pipe in sequence from top to bottom; The storage bin is also provided with a material level detection device for obtaining the reserve of the calcium-based raw material in the storage bin.

7. A calcium-based dry desulfurization process, applied to the calcium-based dry desulfurization equipment as claimed in any one of claims 1 to 6, characterized in that: The calcium-based dry desulfurization process comprises: Connect the flue gas to be treated to the desulfurization reaction system, and set the mass flow rate of the calcium-based raw material consumed in the desulfurization reaction according to the mass flow rate of SO2 in the flue gas to be treated; The air is supplied and the carrier gas is heated through a pneumatic conveying system; According to the set mass flow rate of calcium-based raw materials, the metering feeding system is controlled to quantitatively deliver the calcium-based raw materials to the pneumatic conveying system; The calcium-based raw materials are delivered to the desulfurization reaction system through a pneumatic conveying system, so that the calcium-based raw materials and flue gas react in the inner cylinder structure and the outer cylinder structure.

8. The calcium-based dry desulfurization process according to claim 7, characterized in that: The method of supplying air and heating the carrier gas by the pneumatic conveying system comprises: The fan is started to pressurize the gas in the conveying pipeline, so as to form an airflow in the conveying pipeline from the heating device to the inner cylinder structure; Start the heating device and set its heating temperature to a preset heating temperature value range; When the heating temperature of the heating device reaches a preset heating temperature value range, the calcium-based raw material is quantitatively added into the conveying pipeline by controlling the metering feeding system; Wherein, the preset heating temperature value range is greater than the current dew point temperature of the air.

9. The calcium-based dry desulfurization process according to claim 7, characterized in that: The step of delivering the calcium-based raw material into the desulfurization reaction system through the pneumatic conveying system so that the calcium-based raw material and the flue gas react in the inner cylinder structure and the outer cylinder structure comprises: When the fan is working, the spray gun at the connection between the conveying pipeline and the inner cylinder structure is started synchronously; The calcium-based raw material is sprayed out through a spray gun, and under the action of the swirl blade, the calcium-based raw material and the flue gas to be treated are fully mixed; The mixed flue gas forms a baffled reaction gas between the inner tube structure and the outer tube structure, and the flow rate of the baffled reaction gas is controlled so that the reaction time between the inner tube structure and the outer tube structure is not less than five seconds.

10. The calcium-based dry desulfurization process according to claim 7, characterized in that: The flue gas to be treated is connected to the desulfurization reaction system, and the mass flow rate of the calcium-based raw material consumed in the desulfurization reaction is set according to the mass flow rate of SO2 in the flue gas to be treated: The flue gas to be treated is power station boiler flue gas, and the SO2 concentration in the power station boiler flue gas is less than or equal to 200 mg / Nm 3 , CO2 volume fraction is less than 30%, and the temperature is between 140℃ and 160℃; The purity of the calcium-based raw material is greater than or equal to 85%, the moisture content is less than or equal to 2%, the particle size requirement is 325 mesh screening rate is greater than or equal to 85%, and the specific surface area is greater than or equal to 40m 2 / g, and the bulk density is between 0.4g / L and 0.65g / L.

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