Phosphate-containing waste liquid and waste gas incineration treatment method

Abstract

The invention provides a phosphate-containing waste liquid and waste gas incineration treatment method, and belongs to the technical field of waste liquid and waste gas treatment.The method comprises the steps that phosphate-containing waste liquid and waste gas are added on the basis of a combustor arranged at the bottom of an incinerator, the phosphate-containing waste liquid and the waste gas are fully combusted, and initial flue gas is generated; the initial flue gas flowing into the top of the incinerator is cooled, and first flue gas is obtained; the first flue gas is subjected to heat exchange, and second flue gas is obtained; after the second flue gas enters the settling furnace, the flowing direction of the second flue gas is changed, so that the second flue gas is subjected to solid-gas separation, and third flue gas and solid particles are obtained; and after the third flue gas is cooled to the target temperature, the third flue gas at the target temperature is subjected to denitration treatment. The flue gas is subjected to heat exchange sedimentation treatment, substances such as phosphate in the flue gas are separated and recycled in stages, and simple, efficient and continuous incineration treatment of waste gas and waste liquid generated when the BDO device and the ethylene glycol device are used is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of waste liquid and waste gas treatment, and in particular to a method for incinerating waste liquid and waste gas containing phosphate. Background Art

[0002] During the production process, BDO (1,4-butanediol) and ethylene glycol plants will produce waste liquid containing two inorganic salts, disodium hydrogen phosphate and sodium dihydrogen phosphate. The treatment of the above waste liquid is currently usually carried out by biochemical method or incineration according to the specific components and characteristics of the waste liquid.

[0003] Generally speaking, for organic waste gas and waste liquid, the ignition point during the incineration process is basically between 400 and 700°C, and it is easy to be incinerated and pyrolyzed. For waste liquid containing two inorganic salts, disodium hydrogen phosphate and sodium dihydrogen phosphate, physical property analysis shows that disodium hydrogen phosphate and sodium dihydrogen phosphate will decompose to generate sodium peroxide and phosphorus oxide (phosphorus pentoxide) under high-temperature incineration. Sodium peroxide and carbon dioxide and water in the flue gas will generate sodium carbonate, and sodium peroxide and water vapor in the flue gas will also generate sodium hydroxide. In this process, the post-processing system of the incineration device usually requires efficient and comprehensive utilization of heat and treatment of gas and liquid, as well as treatment of solid waste after burning, so that the harmful components and dust content in the treated liquid, gas, and solid waste meet the current emission standards. In the existing treatment process, the large-scale equipment in the waste heat recovery, heat exchange, denitrification and other links makes the entire incineration process cumbersome and complicated. In addition, during the long-term flue gas treatment process in different temperature ranges, the molten material is easy to adhere to the wall of the heat exchange tube and "scar" to form a dirt layer, which affects the efficiency of the heat exchange components, shortens the operation cycle of the equipment, and even causes production accidents, affecting the incineration efficiency and operational safety of the entire incineration system. Summary of the invention

[0004] In response to the above-mentioned problems, the present application provides a method for incineration treatment of phosphate-containing waste liquid and waste gas. Based on the comprehensive treatment of an incinerator and its post-treatment system, the incinerator and the heat exchange process after incineration, the waste heat recovery process and the denitrification treatment process are closely integrated, saving the floor space of the incineration device and improving the treatment efficiency of the entire incineration device.

[0005] To achieve the purpose of this application, this application provides the following technical solutions:

[0006] The present application provides a method for incinerating phosphate-containing waste liquid and waste gas, comprising:

[0007] After the incinerator is heated to a preset temperature, phosphate-containing waste liquid and waste gas are added through a burner arranged at the bottom of the incinerator, and the phosphate-containing waste liquid and waste gas are fully burned in the incinerator to generate initial flue gas;

[0008] Cooling the initial flue gas flowing into the top of the incinerator based on a radiation evaporator to obtain a first flue gas;

[0009] exchanging heat with the first flue gas in a convection evaporator to obtain cooled second flue gas;

[0010] After the second flue gas enters the settling furnace, the flow direction of the second flue gas is changed in the settling furnace so that the second flue gas undergoes solid-gas separation to obtain third flue gas and solid particles, wherein the solid particles are discharged from the bottom of the settling furnace;

[0011] After the third flue gas is cooled to a target temperature by a steam superheater, a denitration treatment is performed on the third flue gas at the target temperature.

[0012] In a possible implementation, the addition of phosphate-containing waste liquid based on a burner arranged at the bottom of the incinerator includes: spraying the phosphate-containing waste liquid and steam into a mixing chamber of the waste liquid burner at the same time, so that the phosphate-containing waste liquid and the steam are mixed by impact in the mixing chamber to obtain a first atomized waste liquid; wherein the first atomized waste liquid is a gas-liquid mixture; spraying the first atomized waste liquid from a spray hole in the mixing chamber to the incinerator to generate a second atomized waste liquid for combustion, wherein the spray hole is an annular spray hole.

[0013] In a possible implementation, the radiation evaporator is used to cool the initial flue gas flowing into the top of the incinerator to obtain the first flue gas, including: a heat-absorbing coating on the surface of the riser and downcomer of the radiation evaporator performs heat exchange with the initial flue gas to transfer the first heat of the initial flue gas to the inner walls of the riser and downcomer to obtain the first flue gas; wherein the riser and the downcomer are vertical water pipe-type structures evenly arranged inside the radiation evaporator.

[0014] In a possible implementation, the convection evaporator includes at least a first sub-convection evaporator and a second sub-convection evaporator; the heat exchanging the first flue gas in the convection evaporator to obtain the cooled second flue gas includes: heat exchanging the first flue gas in the first sub-convection evaporator to obtain the second sub-flue gas, and allowing the second sub-flue gas to enter the second sub-convection evaporator; heat exchanging the second sub-flue gas in the second sub-convection evaporator to obtain the second flue gas; wherein the temperature of the second flue gas is lower than the temperature of the second sub-flue gas.

[0015] In a possible implementation, the denitrification treatment of the third flue gas at the target temperature includes: mixing the third flue gas at the target temperature with a denitrification agent to obtain a denitrified mixed flue gas, and passing the denitrified mixed flue gas through a first catalyst bed and a second catalyst bed in sequence to obtain a target denitrified flue gas; wherein the denitrification agent is uniformly sprayed into the denitrification section from the top of the denitrification section, and is sprayed into the denitrification section simultaneously with the third flue gas; the denitrification agent is aqueous ammonia.

[0016] In one possible implementation, the denitration section includes a steam soot blower; the method also includes: when the denitration mixed flue gas does not pass through the second catalyst bed, dust and salt on the surface of the first denitration catalyst of the second catalyst bed are removed based on a first preset time interval to maintain the activity of the first denitration catalyst; when the denitration mixed flue gas does not pass through the first catalyst bed, dust and salt on the surface of the second denitration catalyst of the first catalyst bed are removed based on a second preset time interval to maintain the activity of the second denitration catalyst.

[0017] In a possible implementation, after the third flue gas at the target temperature is subjected to denitrification treatment, the method further includes: cooling the denitrified flue gas based on a boiler water preheater to obtain second solid particles and a fourth flue gas; wherein the second solid particles are discharged from the bottom of the boiler water; and the fourth flue gas is introduced into a chimney for discharge.

[0018] In a possible implementation, introducing the fourth flue gas into the chimney includes: introducing the fourth flue gas into a bag filter, and after the fourth flue gas is processed to a preset standard in the bag filter, introducing the fourth flue gas that reaches the preset standard into the chimney for discharge based on an induced draft fan.

[0019] In a possible implementation, the initial flue gas further includes molten salt particles, and the method further includes: after the molten salt particles flow out from the bottom of the incinerator, cooling the molten salt particles using a water cooler to obtain solid salt particles.

[0020] In a possible implementation, the method further includes: when the monitoring system detects that there is an abnormality in the start-up of the combustion supply process, cutting off the fuel supply to the incinerator; when the monitoring system detects that the gas pressure and / or wind pressure in the incineration chamber is outside a preset threshold range, stopping the ignition process in the incineration chamber.

[0021] The incineration treatment method for phosphate-containing waste liquid and waste gas provided in the present application is for incineration flue gas in different temperature ranges. By performing heat exchange and sedimentation treatment on the flue gas in stages, substances such as sodium carbonate, sodium peroxide, sodium hydroxide and gaseous phosphorus oxide in the flue gas are separated and recovered in stages, thereby achieving simple, efficient and continuous incineration treatment of waste gas and waste liquid generated by the BDO device and the ethylene glycol device during use, avoiding slagging blockage and corrosion problems caused by incineration, and efficiently recovering substances such as sodium carbonate, sodium peroxide, sodium hydroxide and gaseous phosphorus oxide in the waste liquid and waste gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present application and form a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application.

[0023] Figure 1 An optional flow chart of a method for incinerating phosphate-containing waste liquid and waste gas provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the structure of a waste liquid storage tank provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the structure of the exhaust gas buffer tank provided in the embodiment of the present application;

[0026] Figure 4 A schematic diagram of the structure of an internal mixing steam atomizing nozzle provided in an embodiment of the present application;

[0027] Figure 5 An optional flow chart of a method for incinerating phosphate-containing waste liquid and waste gas provided in an embodiment of the present application;

[0028] Figure 6 A schematic diagram of the planar structure of a system for incinerating phosphate-containing waste liquid and waste gas provided in an embodiment of the present application;

[0029] Figure 7 A schematic diagram of the planar structure of an incinerator of a phosphate-containing waste liquid and waste gas incineration treatment system provided in an embodiment of the present application;

[0030] Figure 8 A schematic diagram of the planar structure of a cooling and settling furnace of a phosphate-containing waste liquid and waste gas incineration treatment system provided in an embodiment of the present application;

[0031] Fig. 9 A schematic diagram of the planar structure of a denitration settling furnace of a phosphate-containing waste liquid and waste gas incineration treatment system provided in an embodiment of the present application;

[0032] Fig.10A schematic diagram of the structure of a steam circulation system for a phosphate-containing waste liquid and waste gas incineration treatment system provided in an embodiment of the present application.

[0033] Reference numerals:

[0034] 101-waste liquid inlet, 102-waste liquid outlet, 103-exhaust port, 104-agitator, 105-pressure port, 106-drain port, 107-liquid level meter; 201-air inlet, 202-air outlet, 203-pressure port, 204-safety valve, 205-drain port;

[0035] 100 - incinerator, 110 - incineration chamber, 120 - radiation evaporator, 130 - waste liquid burner, 140 - waste gas burner, 150 - first discharge port, 160 - condenser, 170 - output end of incinerator;

[0036] 200-cooling and settling furnace, 210-cooling and settling furnace input end, 220-first sub-convection evaporator, 230-second sub-convection evaporator, 240-settling chamber, 241-baffle, 242-standby air input end, 250-steam superheater, 260-cooling and settling furnace output end, 270-second discharge port, 280-steam soot blower;

[0037] 300-denitrification settling furnace, 310-denitrification settling furnace input end, 320-denitrification agent spraying assembly, 330-partition plate, 340-boiler water preheater, 350-denitrification settling furnace output end, 360-third discharge port, 370-first soot blowing assembly, 380-second soot blowing assembly;

[0038] 400-Bag dust collector;

[0039] 500-Chimney;

[0040] 600-Stand;

[0041] 700-Steam Pack. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of this application, unless otherwise specified, "plurality" means two or more.

[0044] Example 1

[0045] Figure 1 The schematic diagram of the process of incineration treatment of phosphate-containing waste liquid and waste gas provided in the embodiment of the present application is a schematic diagram of the process of incineration treatment of phosphate-containing waste liquid and waste gas provided in the embodiment of the present application. The incineration treatment method of phosphate-containing waste liquid and waste gas provided in the embodiment of the present application can be applied to a phosphate-containing waste liquid and waste gas treatment system, such as Figure 1 As shown, the method for incinerating phosphate-containing waste liquid and waste gas in the embodiment of the present application includes the following steps S101 to S105:

[0046] Step S101, after the incinerator is heated to a preset temperature, phosphate-containing waste liquid and waste gas are added through a burner arranged at the bottom of the incinerator, and the phosphate-containing waste liquid and waste gas are fully burned in the incinerator to generate initial flue gas.

[0047] In the embodiment of the present application, after the temperature of the incineration chamber of the incinerator is heated to the incineration temperature, the phosphate-containing waste liquid is transported from the waste liquid storage tank to the waste liquid burner by a waste liquid pump, so that the waste liquid is atomized by steam in the waste liquid burner, and then sprayed into the incineration chamber of the incinerator through the waste liquid burner arranged at the bottom of the incinerator for incineration and pyrolysis, generating flue gas and high-temperature molten ammonium carbonate, sodium peroxide, sodium hydroxide and gaseous phosphorus oxide, wherein the waste liquid storage tank contains a mixed waste liquid containing multiple components. Here, the incineration chamber temperature corresponds to the preset temperature in the present application. As a feasible implementation method, the preset temperature can be 1100°C, the maximum operating temperature of the incinerator can be 1500°C, and the outer wall temperature of the furnace body is not higher than 60°C. In the embodiment of the present application, after the waste gases from the outside of the incineration device are evenly mixed in the waste gas buffer tank, they enter the incineration chamber through the waste gas and auxiliary fuel burner for incineration and pyrolysis.

[0048] In the embodiment of the present application, the initial flue gas generated by the incineration chamber is a mixture of the flue gas after the incineration of the waste liquid and the flue gas generated after the incineration of the waste gas, which includes at least molten sodium carbonate, sodium peroxide and sodium hydroxide. The initial flue gas flow rate is relatively low. The molten sodium carbonate, sodium peroxide and sodium hydroxide settle and flow downward under the action of gravity. After flowing out in a molten state from the bottom of the incineration chamber, they are cooled into a solid state by the desalted water and precipitated based on the surface of the water cooler located at the bottom of the incineration chamber.

[0049] In the embodiments of the present application, Figure 2As shown, the waste liquid storage tank is a vertical structure, in which a waste liquid inlet 101, a waste liquid outlet 102, an exhaust port 103, an agitator 104, a pressure port 105, a sewage outlet 106 and a liquid level meter 107 are arranged. The exhaust port 103 is used to automatically open the exhaust pressure relief when the pressure in the waste liquid storage tank is detected to exceed the preset threshold value to ensure the safety of the storage tank. In the embodiment of the present application, the waste liquid storage tank and the waste liquid delivery system connected to the waste liquid pump and the waste liquid burner take sealing measures to prevent leakage of waste liquid. Among them, the capacity of the waste liquid storage tank must meet the operating consumption of the incineration device for at least 15 days, that is, it must reach at least 200m3. It should be noted that the incineration device refers to the incineration treatment system used in the phosphate-containing waste liquid and waste gas incineration treatment method of the embodiment of the present application, including the post-processing process after the incinerator.

[0050] In the embodiments of the present application, Figure 3 As shown, the exhaust gas buffer tank is a vertical structure, in which an air inlet 201, an air outlet 202, a pressure port 203, a safety valve 204, and a sewage outlet 205 are provided.

[0051] In the embodiment of the present application, the incinerator adopts vertical bottom burning, and a plurality of burners are arranged circumferentially at the bottom of the incinerator. The burners include at least a waste liquid burner and a waste gas burner. In order to ensure the atomization quality after the waste liquid and steam are efficiently mixed, the waste liquid burner can adopt superheated steam-assisted atomization based on an internal mixing steam atomizing nozzle, such as Figure 4 As shown, the waste liquid of the internal mixing steam atomizing nozzle is sprayed into the mixing chamber from the middle annular hole of the nozzle, and collides and mixes with the steam sprayed from the corresponding small hole on the side of the nozzle to perform the first atomization; then after the pressure inside the mixing chamber is established, the gas-liquid mixture after the first atomization is sprayed from the annular spray hole of the mixing chamber to the incinerator for combustion in the incinerator. Here, in order to obtain a smaller and uniform distribution of the diameter of the atomized droplets, it is necessary to reasonably adjust the parameters such as the pore diameter, liquid pore diameter, gas-liquid momentum ratio, and mixing chamber length. Considering that the waste liquid not only participates in the combustion reaction, but also absorbs a lot of heat, in order to reduce the impact of the waste liquid spray on the burner flame, it is necessary to control the spray angle and jet velocity to achieve a better match with the furnace.

[0052] In the embodiment of the present application, the exhaust gas burner adopts a swirl form to increase the contact area between the exhaust gas and the combustion-supporting air to make the combustion more complete.

[0053] As a feasible implementation method, 8 burners are arranged circumferentially at the bottom of the incinerator of this embodiment, of which 4 waste liquid burners are arranged opposite to each other in pairs on both sides of the bottom of the incinerator; 4 exhaust gas + auxiliary fuel burners (corresponding to the exhaust gas burners in the embodiment of the present application) are arranged opposite to each other in pairs on both end surfaces of the bottom of the incinerator; the exhaust gas + auxiliary fuel burners are combined burners, which can burn auxiliary fuel gas or exhaust gas alone, or burn exhaust gas and auxiliary fuel gas at the same time; the exhaust gas + auxiliary fuel burners can be used for baking the furnace and heating; all exhaust gas + auxiliary fuel burners are provided with a ever-burning lamp and a ever-burning lamp combined ignition rod. When one of the exhaust gas + auxiliary fuel burners is an ignition burner, 3 flame monitors are configured, and the other exhaust gas + auxiliary fuel burners are each configured with a flame detector. The entire system is configured with an automatic igniter to realize the PLC automatic ignition function.

[0054] Step S102: Cooling the initial flue gas flowing into the top of the incinerator based on a radiation evaporator to obtain a first flue gas.

[0055] In an embodiment of the present application, after the flue gas at a preset temperature flows out from the incineration chamber of the incinerator, the initial flue gas is subjected to heat exchange cooling by a radiation evaporator located at the top of the incinerator, and the flue gas subjected to heat exchange cooling flows out through the outlet of the radiation evaporator to obtain a first flue gas. Among them, the molten sodium peroxide and sodium hydroxide in the initial flue gas continue to be separated, and the solid sodium carbonate after cooling will settle into the incineration chamber of the incinerator, and then melt and be discharged from the bottom of the incineration chamber. Here, it should be noted that the molten slag discharged from the bottom of the incinerator in steps S101 to S102 is most of the residue in the waste liquid and waste gas treatment process (excluding phosphorus oxide). In an embodiment of the present application, after the above-mentioned molten slag flows out from the bottom of the incinerator, the molten slag (corresponding to the molten salt particles in the embodiment of the present application) is cooled based on a water cooler to obtain solid salt particles.

[0056] In an embodiment of the present application, step S102 specifically includes: performing heat exchange with the initial flue gas based on the coating for absorbing heat on the surface of the riser and the downcomer of the radiation evaporator, so as to transfer the first heat of the initial flue gas to the inner walls of the riser and the downcomer to obtain the first flue gas; wherein the riser and the downcomer are vertical water pipe-type structures uniformly arranged inside the radiation evaporator; the coating for absorbing heat can be selected from metal oxides such as iron oxide, metal nitrides, ceramic materials or composite materials.

[0057] In the embodiment of the present application, the temperature of the first flue gas at the outlet of the radiation evaporator is 600°C±10°C.

[0058] Step S103: exchanging heat with the first flue gas in a convection evaporator to obtain cooled second flue gas.

[0059] In an embodiment of the present application, the first flue gas coming out of the radiation evaporator contains gaseous phosphorus oxide, a small amount of solid sodium carbonate particles, a small amount of molten sodium peroxide and sodium hydroxide droplets. The first flue gas flows through a convection evaporator to obtain a second flue gas after heat exchange cooling, wherein a small amount of molten sodium peroxide and sodium hydroxide droplets solidify, and the gaseous phosphorus oxide becomes liquid and then becomes solid.

[0060] In the embodiments of the present application, Figure 5 As shown, step S103 may include the following contents of steps S1031 to S1032:

[0061] Step S1031, exchanging heat with the first flue gas in the first sub-convective evaporator to obtain second sub-flue gas, and allowing the second sub-flue gas to enter the second sub-convective evaporator;

[0062] Step S1032: performing heat exchange on the second sub-flue gas in the second sub-convection evaporator to obtain the second flue gas; wherein the temperature of the second flue gas is lower than the temperature of the second sub-flue gas.

[0063] In the embodiment of the present application, the temperature of the second sub-flue gas at the outlet of the first sub-convective evaporator is 380±10°C; the temperature of the second flue gas at the outlet of the second sub-convective evaporator is 320°C±10°C.

[0064] Step S104: after the second flue gas enters the settling furnace, the flow direction of the second flue gas is changed in the settling furnace to separate the second flue gas into solid and gas to obtain third flue gas and solid particles, wherein the solid particles are discharged from the bottom of the settling furnace.

[0065] In an embodiment of the present application, the second flue gas exiting the second sub-convection evaporator contains a small amount of sodium carbonate particles, a small amount of sodium peroxide particles, a small amount of sodium hydroxide particles and phosphorus oxide particles. After the second flue gas is transported to the settling furnace, it flows downward, returns upward and then horizontally in the settling furnace. During this period, solid particles (corresponding to the solid particles in the embodiment of the present application) settle at the bottom of the settling furnace and are discharged from the bottom of the settling furnace.

[0066] In the embodiment of the present application, the settling furnace is an air distribution settling chamber, which is used to collect gas-solid particulate matter generated in the convection evaporator and particulate matter such as P2O5 and sodium salt that are cooled and solidified by the air distribution. As a feasible implementation method, the air distribution settling chamber of the embodiment of the present application includes a conical shell, an air inlet, and a slag discharge port at the bottom of the settling furnace. When the second flue gas passes through the air distribution settling chamber, cold air is introduced through the air inlet, so that P2O5, sodium salt and other substances in the second flue gas are cooled and solidified and discharged from the slag discharge port.

[0067] Step S105: After cooling the third flue gas to a target temperature using a steam superheater, denitrification treatment is performed on the third flue gas at the target temperature.

[0068] In the embodiment of the present application, the third flue gas exiting the settling furnace passes through the steam superheater horizontally to achieve further cooling.

[0069] In the embodiment of the present application, the steam superheater is mainly composed of a shell, a heat exchange tube, a steam inlet, a steam outlet, etc. When the flue gas passes through the heat exchange tube of the steam superheater, the saturated steam in the heat exchange tube is heated to heat the saturated steam into superheated steam. In the embodiment of the present application, the preset temperature is 300℃±10℃.

[0070] In the embodiment of the present application, after the third flue gas reaches the target temperature, the third flue gas contains a very small amount of sodium carbonate particles, a very small amount of sodium peroxide particles, a very small amount of sodium hydroxide particles and a small amount of phosphorus oxide particles, and the third flue gas is subjected to denitration treatment in the denitration section. In the embodiment of the present application, after the third flue gas comes out of the steam superheater, it enters the vertical flue gas denitration section downward, and is fully mixed with the flue gas containing the denitration agent uniformly sprayed from the top of the flue gas denitration section at the top of the flue gas denitration section, and passes through two catalyst beds in sequence downward, and is completely denitrated, reducing the nitrogen oxide content in the flue gas to 50mg / m 3 For example, the denitrification agent may be ammonia generated by thermal decomposition of urea.

[0071] In the embodiment of the present application, the denitration stage adopts a selective catalytic reduction (SCR) denitration hybrid process for denitration, which includes a control and monitoring system, a urea solution storage system, a transportation system, a denitration reactor and ancillary systems. Here, the control and monitoring system, the urea solution storage system, and the transportation system can refer to the existing design and will not be described in detail. In the embodiment of the present application, the denitration reactor in the SCR denitration hybrid process (corresponding to the denitration settling furnace 300 in the embodiment of the present application) has a denitration component inside, such as Fig. 9As shown, the denitration component includes: a denitration agent spraying component 320 and a partition 330; the denitration agent spraying component 320 is used to spray the denitration agent into the denitration settling furnace 300, and the partition 330 can be opened and closed, and when closed, the denitration settling furnace is divided into a plurality of spaces; optionally, the partition 330 is three, and the denitration settling furnace 300 is divided into four spaces, so that the third flue gas and the denitration agent can fully react; as a feasible embodiment, the bottom passage of the denitration settling furnace 300 has a heat exchange component 340, which is used to carry out denitration The third flue gas after the reaction is cooled to allow the solid particles to settle; the flue gas passage of the cooling and settling furnace 200 is provided with a first soot blowing assembly 280 for sweeping the solid particles on the surface of the second heat exchange assembly 220 and the third heat exchange assembly 230; the partition 330 of the denitrification settling furnace 300 is provided with a second soot blowing assembly 370 for sweeping the solid particles on the surface of the partition 330; the bottom passage of the denitrification settling furnace 300 is provided with a third soot blowing assembly 380 for sweeping the solid particles on the surface of the fifth heat exchange assembly 340.

[0072] In the embodiment of the present application, the hydrolysis flue gas pyrolysis method is adopted, that is, urea is first dissolved in a urea dissolving tank with warm water greater than 38°C, and then sprayed into the front flue of the denitration reactor through a metering and conveying system. Since the flue gas temperature at the inlet of the denitration reactor is mostly greater than 200°C, spraying urea at this temperature can prepare most of the urea into ammonia, and can save investment.

[0073] In the embodiment of the present application, the flue gas denitrification section is provided with a steam soot blower (corresponding to the soot blowing assembly of the embodiment of the present application (including the first soot blowing assembly 280, the second soot blowing assembly 370 and the third soot blowing assembly 380)), which removes dust and salt accumulated on the surface of the denitrification agent from time to time to maintain the reaction activity of the catalyst.

[0074] In an embodiment of the present application, in step S105, the third flue gas at the target temperature is subjected to a denitrification treatment, including: mixing the third flue gas at the target temperature with a denitrification agent to obtain a denitrified mixed flue gas, and allowing the denitrified mixed flue gas to sequentially pass through a first catalyst bed and a second catalyst bed arranged in a denitrification section to obtain a target denitrified flue gas; wherein the denitrification agent is uniformly sprayed into the denitrification section from the top of the denitrification section, and is sprayed into the denitrification section simultaneously with the third flue gas; illustratively, the denitrification agent is aqueous ammonia.

[0075] As a feasible implementation mode, when the denitrification mixed flue gas has not passed through the second catalyst bed, the dust and salt on the surface of the first denitrification catalyst of the second catalyst bed are cleared based on a first preset time interval to maintain the activity of the first denitrification catalyst; when the denitrification mixed flue gas has not passed through the first catalyst bed, the dust and salt on the surface of the second denitrification catalyst of the first catalyst bed are cleared based on a second preset time interval to maintain the activity of the second denitrification catalyst.

[0076] In the embodiment of the present application, in view of the fact that the third flue gas after denitration in the flue gas denitration stage may still contain a very small amount of sodium carbonate particles, a very small amount of sodium peroxide particles, a very small amount of sodium hydroxide particles and a small amount of phosphorus oxide particles, in order to remove the above particles, a deoxygenated water preheater and a desalted water preheater (corresponding to the boiler water preheater in the embodiment of the present application) are provided after the flue gas denitration stage, so that the third flue gas after denitration passes downward through the deoxygenated water preheater and the desalted water preheater in turn to be further cooled to 140°C ± 10°C, thereby the solid particles are further discharged from the lowest point of the flue at the bottom of the desalted water preheater, wherein the desalted water comes from outside the boundary area, and is deoxygenated by the deaerator after preheating, and the deoxygenated water comes from the deaerator through the deoxygenated water pump, and enters the air bag after overheating. It should be noted that the air used in the embodiment of the present application adopts a forced air supply configured with a blower.

[0077] The incineration treatment method for phosphate-containing waste liquid and waste gas of the embodiment of the present application is for incineration flue gas in different temperature ranges. By performing heat exchange and sedimentation treatment on the flue gas in stages, substances such as sodium carbonate, sodium peroxide, sodium hydroxide and gaseous phosphorus oxide in the flue gas are separated and recovered in stages, thereby achieving simple, efficient and continuous incineration treatment of waste gas and waste liquid generated by the BDO device and the ethylene glycol device during use, avoiding slagging blockage and corrosion problems caused by incineration, and efficiently recovering substances such as sodium carbonate, sodium peroxide, sodium hydroxide and gaseous phosphorus oxide in the waste liquid and waste gas.

[0078] Example 2

[0079] Based on the above embodiments, in the method for incinerating phosphate-containing waste liquid and waste gas provided in the embodiments of the present application, after step S105, the flue gas (corresponding to the fourth flue gas in the embodiments of the present application) exiting the desalted water preheater can be introduced into the bag filter, and after the flue gas is treated to a preset standard in the bag filter, the flue gas reaching the preset standard is introduced into the chimney through the induced draft fan for discharge. Here, the flue gas exiting the desalted water preheater may still contain a very small amount of sodium carbonate particles, a very small amount of sodium peroxide particles, a very small amount of sodium hydroxide particles, and a very small amount of phosphorus oxide particles.

[0080] In the embodiment of the present application, the bag dust collector body includes an upper box, a middle box and a plurality of ash hoppers, wherein the upper box is a clean air chamber, which is connected to the outlet flue; the middle box is composed of a filter chamber and a settling chamber, each filter chamber is connected to a diversion distribution device, the diversion device is a partition plate for guiding dusty flue gas and purified airflow, and the diversion device is also a device for guiding airflow from the bottom into the filter area; each ash hopper is connected to the diversion distribution device, the airflow in the entire filter chamber is evenly distributed and connected to the middle box of the dust collector, and the flue gas naturally settles large particles of dust in the dusty gas directly into the ash hopper when passing through the settling chamber of the middle box, and is provided with a level meter, a vibrator, an inspection door, a gate valve, an automatic ash discharge valve, etc. The dust collector of this embodiment adopts carbon steel as the structural material of steel and steel plate. After the steel and steel plates used in the box are delivered, they are first sandblasted to remove rust. The box shell is made of steel plates and profiles, with longitudinal and transverse reinforcement ribs on the surface, which is sealed and rainproof. There is no dead corner or fly ash accumulation area in the box shell. For example, the bag dust collector adopts a pulse bag dust collector, and the cleaning method adopts the "online chamber" pulse spraying method. The gas purification method is external filtration. The dust-containing gas enters the air inlet chamber from the air inlet, passes through the guide plate and enters the filter chamber from the bottom. The dust-containing flue gas first passes through the sedimentation chamber to remove large particles and then enters the filtration area. The airflow passes through the diversion distribution device, and the natural flow direction is appropriately diverted and distributed, and enters the bag chamber evenly from the bottom. The airflow is evenly distributed in the entire filter chamber. The dust particles in the dust-containing gas naturally settle in the sedimentation chamber in the air inlet duct and directly fall into the ash hopper. Under the guidance of the diversion device, the floating dust enters the filter area of ​​the middle box with the airflow and is adsorbed on the outer surface of the filter bag. The clean gas after filtration passes through the filter bag and is discharged through the exhaust port of the upper box.

[0081] Example 3

[0082] Based on the above embodiments, this embodiment provides a phosphate-containing waste liquid and waste gas incineration treatment system, such as Figure 6 As shown, the phosphate-containing waste liquid and waste gas incineration treatment system includes: an incinerator 100, a cooling and settling furnace 200, a denitration and settling furnace 300, a bag filter 400, and a chimney 500; after the incinerator output end 170 of the incinerator 100 is connected to the convection evaporator input end at the top of the cooling and settling furnace 200, the first flue gas coming out of the incinerator is subjected to heat exchange cooling to obtain the second flue gas, and the convection evaporator output end is connected to the settling furnace input end 210 for transferring the heat exchanged flue gas to the second flue gas. The second flue gas obtained after heating is introduced into the settling furnace 200; the cooling settling furnace output end 260 of the settling furnace 200 is connected with the denitration settling furnace input end 310 of the denitration settling furnace 300 based on the steam superheater, and is used to denitrate the third flue gas cooled to the target temperature after settling; the denitration settling furnace 300 is used to denitrate the third flue gas that reaches the target temperature to obtain the fourth flue gas, and settle the fourth flue gas obtained by heat exchange of the fourth flue gas.

[0083] In the embodiments of the present application, Figure 7 As shown, the incinerator 100 has a radiation evaporator 120 at the top and an incineration chamber 110 at the bottom; the incineration chamber 110 has a first discharge port 150 at the bottom, and a waste liquid burner 130 and a waste gas burner 140 at the bottom wall; the incineration chamber 110 has a waste liquid burner 130 and a waste gas burner 140 at the bottom; the waste gas burner 140 is used to spray the waste gas generated by the BDO device and the ethylene glycol device when in use into the combustion chamber for incineration; the waste liquid burner 130 is used to spray the waste liquid generated by the BDO device and the ethylene glycol device when in use into the combustion chamber in the form of aerosol for incineration; wherein the waste liquid burner 130 has an atomizing steam channel and a waste liquid channel, which are used to atomize and spray the waste liquid through atomizing steam, and the incinerator 100 has a spare air inlet; the incinerator 100 has a condenser 160 at the bottom, which is used to cool the molten salt flowing out from the lower end of the incinerator 100.

[0084] In the embodiments of the present application, Figure 8 As shown, the upper part of the cooling and settling furnace 200 is a flue gas passage, and the lower part is a settling chamber 240; a first sub-convection evaporator 220 and a second sub-convection evaporator 230 are arranged in the flue gas passage; wherein the first sub-convection evaporator 220 is used to perform heat exchange and cooling on the first flue gas, and the second sub-convection evaporator 230 is used to continue to control the temperature of the first flue gas to keep it within a preset range; a baffle 241 is provided on the top of the settling chamber 240; the baffle 241 extends into the interior of the settling chamber 240, and the bottom of the baffle 241 is lower than The bottom of the cooling and settling furnace output end 260; wherein, the baffle 241 allows the fourth flue gas to sink into the settling chamber, and in the process of raising the output cooling and settling furnace 200, as many solid particles in the second flue gas as possible are settled into the settling chamber 240; the cooling and settling furnace output end 260 also has a steam superheater 250, which is used to exchange heat with the third flue gas separated from the cooling and settling furnace, wherein the steam superheater 250 is used to control the temperature of the third flue gas within a preset range, thereby ensuring that the third flue gas and the denitrification agent undergo an efficient denitrification reaction.

[0085] In the embodiments of the present application, Fig. 9As shown, the denitration settling furnace 300 has a denitration component inside; the denitration component includes: a denitration agent spraying component 320 and a partition 330; the denitration agent spraying component 320 is used to spray the denitration agent into the denitration settling furnace 300, and the partition 330 can be opened and closed, and when closed, the interior of the denitration settling furnace is divided into multiple spaces; there are three partitions 330, which divide the interior of the denitration settling furnace 300 into four spaces, so that the fourth flue gas can fully react with the denitration agent; the bottom passage of the denitration settling furnace 300 has a boiler water preheater 340, which is used to cool the flue gas after the denitration reaction to settle the solid particles. The flue gas passage of the cooling and settling furnace 200 is provided with a steam soot blower 280 for sweeping the solid particles on the surface of the first sub-convection evaporator 220 and the second sub-convection evaporator 230; the partition 330 of the denitrification and settling furnace 300 is provided with a first soot blowing assembly 370 for sweeping the solid particles on the surface of the partition 330; the bottom passage of the denitrification and settling furnace 300 is provided with a second soot blowing assembly 380 for sweeping the solid particles on the surface of the boiler water preheater 340.

[0086] In the embodiment of the present application, boiler water (saturated) comes from the air bag through the boiler water circulation pump, and the generated water-vapor mixture returns to the air bag for steam-water separation, and the saturated steam separated from the air bag is sent out of the boundary area, such as Fig.10 Shown is a schematic flow diagram of the steam cycle process.

[0087] Example 4

[0088] Based on the above-mentioned Examples 1-3, this Example performs the following test calculations on the incineration results:

[0089] The process parameters of waste liquid and waste gas in this embodiment are as follows:

[0090] (1) Salt-containing wastewater

[0091] Total mass flow: 380kg / h;

[0092]

[0093] (2) Wastewater

[0094] Total mass flow rate: 220.83kg / h;

[0095]

[0096] (3) Waste gas

[0097] Total mass flow: 610kg / h;

[0098]

[0099]

[0100] (4) Auxiliary fuel

[0101] Fuel Name natural gas Calorific value <![CDATA[8400kcal / Nm 3 ]]>

[0102] By calculation, the co-firing is 20Nm 3 / h fuel gas, with 26067.8Nm 3 / h cold air can maintain the combustion temperature of 1100℃ stable operation. The cold air is added to the combustion air from the burner. At this time, the heat load is 10.7MW and the smoke volume out of the combustion chamber is 27856.7Nm 3 / h, where (mol%):

[0103] O2:11.64%, N2:74.61%, CO2:5.86%, H2O:7.89%,

[0104] P2O5: 9.0kg / h Na2CO3 (containing a small amount of Na2O2 and NaOH): 8.5kg / h, it is estimated that 70% (12.3kg / h) is discharged in molten state from the bottom of the incineration chamber, 25% (4.4kg / h) is discharged intermittently in solid form from the sedimentation chamber and the bottom of the denitrification section, and 5% (0.9kg / h) is discharged from the bottom of the bag dust collector.

[0105] The excess air coefficient is 2.4, which is very reliable incineration data.

[0106] Dry basis oxygen content (mol%): 12.64%, slightly greater than the requirement of 9% to 11% on dry basis oxygen content in GB18484-2020.

[0107] The external output is 15170kg / h of 1.3MPa saturated steam.

[0108] in:

[0109] The flue gas volume from the radiation evaporator located at the top of the incinerator is 33043.3Nm 3 / h, where (mol%):

[0110] O2:13.11%, N2:75.30%, CO2:4.94%, H2O:6.65%,

[0111] The flue gas volume out of the settling chamber is 39665Nm 3 / h, where (mol%):

[0112] O2:14.43%, N2:75.92%, CO2:4.11%, H2O:5.54%,

[0113] Emission of three wastes: This device emits flue gas and solid waste.

[0114] Under ideal conditions, smoke emissions: 29856.7Nm 3 / h, exhaust gas temperature 143℃.

[0115] Flue gas components (mol%):

[0116] O2:11.64%, N2:74.61%, CO2:5.86%, H2O:7.89%,

[0117] NO X :≤50mg / m 3

[0118] Dust content: ≤10mg / m 3 , mainly phosphorus oxide and sodium carbonate (containing a small amount of sodium peroxide and sodium hydroxide).

[0119] In the embodiment of the present application, the waste liquid and waste gas enter the burner through the storage and transportation system and are fully incinerated in the incineration chamber to generate hot flue gas at about 1100°C. The flue gas passes through the radiation evaporator at the upper part of the incineration chamber, and the temperature is reduced to 600°C. Then, it enters the convection evaporator I, and the temperature is reduced to 380°C. Then, it enters the convection evaporator and is cooled to 320°C. Then, it enters the sedimentation section to settle the solid particles in the flue gas, and then enters the SCR denitration section after the temperature is reduced to 300°C through the steam superheater, and the nitrogen oxide content in the flue gas is reduced to 50mg / m 3 After denitration, the flue gas passes through the deoxygenated water preheater and the desalted water preheater to recover the residual heat and preheat the desalted water and deoxygenated water. After the flue gas passes through the desalted water preheater, the temperature drops to 143°C and enters the bag filter to recover solid particles. The particle content drops to 10mg / m 3 , and discharged into the atmosphere through the chimney through the induced draft fan.

[0120] The above embodiments are only used to illustrate the technical solution of the present application, but not to limit it. The present application is not limited to the exact structure described above and illustrated in the accompanying drawings, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, various changes and modifications made without departing from the concept of the present application should be deemed to belong to the protection scope of the present application.

[0121] In the several embodiments provided in the present application, it should be understood that the disclosed systems, modules and methods can be implemented in other ways. For example, the module embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, modules or units, which can be electrical, mechanical or other forms.

[0122] The above embodiments are only used to illustrate the technical solution of the present application, but not to limit it. The present application is not limited to the exact structure described above and illustrated in the accompanying drawings, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, various changes and modifications made without departing from the concept of the present application should be deemed to belong to the protection scope of the present application.

Claims

1. A method for incinerating phosphate-containing waste liquid and waste gas, characterized in that: include: After the incinerator is heated to a preset temperature, phosphate-containing waste liquid and waste gas are added through a burner arranged at the bottom of the incinerator, and the phosphate-containing waste liquid and waste gas are fully burned in the incinerator to generate initial flue gas; Cooling the initial flue gas flowing into the top of the incinerator based on a radiation evaporator to obtain a first flue gas; exchanging heat with the first flue gas in a convection evaporator to obtain cooled second flue gas; After the second flue gas enters the settling furnace, the flow direction of the second flue gas is changed in the settling furnace so that the second flue gas undergoes solid-gas separation to obtain third flue gas and solid particles, wherein the solid particles are discharged from the bottom of the settling furnace; After the third flue gas is cooled to a target temperature by a steam superheater, a denitration treatment is performed on the third flue gas at the target temperature.

2. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 1, characterized in that: The method of adding phosphate-containing waste liquid to a burner disposed at the bottom of the incinerator comprises: The phosphate-containing waste liquid and steam are simultaneously sprayed into a mixing chamber of a waste liquid burner, so that the phosphate-containing waste liquid and the steam are mixed by collision in the mixing chamber to obtain a first atomized waste liquid; wherein the first atomized waste liquid is a gas-liquid mixture; The first atomized waste liquid is sprayed from the spray hole of the mixing chamber to the incinerator to generate the second atomized waste liquid for combustion, wherein the spray hole is an annular spray hole.

3. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 1, characterized in that: The method of cooling the initial flue gas flowing into the top of the incinerator by a radiation evaporator to obtain the first flue gas comprises: The heat-absorbing coating on the surface of the riser and downcomer of the radiation evaporator performs heat exchange with the initial flue gas to transfer the first heat of the initial flue gas to the inner walls of the riser and downcomer to obtain the first flue gas; wherein the riser and downcomer are vertical water-tube type structures uniformly arranged inside the radiation evaporator.

4. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 1, characterized in that: The convection evaporator at least includes a first sub-convection evaporator and a second sub-convection evaporator; the first flue gas is subjected to heat exchange in the convection evaporator to obtain the cooled second flue gas, including: exchanging heat with the first flue gas in the first sub-convective evaporator to obtain second sub-flue gas, and allowing the second sub-flue gas to enter the second sub-convective evaporator; The second sub-flue gas is heat exchanged in the second sub-convection evaporator to obtain the second flue gas; wherein the temperature of the second flue gas is lower than the temperature of the second sub-flue gas.

5. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 1, characterized in that: The denitrification treatment of the third flue gas at the target temperature includes: The third flue gas at the target temperature is mixed with a denitrifying agent to obtain a denitrifying mixed flue gas, and the denitrifying mixed flue gas is passed through a first catalyst bed and a second catalyst bed in sequence to obtain a target denitrifying flue gas; wherein the denitrifying agent is sprayed evenly into the denitrifying section from the top of the denitrifying section, and is sprayed into the denitrifying section simultaneously with the third flue gas; the denitrifying agent is aqueous ammonia.

6. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 5, characterized in that: The denitration section includes a steam soot blower; the method further includes: When the denitration mixed flue gas does not pass through the second catalyst bed, dust and salt on the surface of the first denitration catalyst of the second catalyst bed are removed based on a first preset time interval to maintain the activity of the first denitration catalyst; When the denitration mixed flue gas does not pass through the first catalyst bed, dust and salt on the surface of the second denitration catalyst of the first catalyst bed are removed based on a second preset time interval to maintain the activity of the second denitration catalyst.

7. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 1, characterized in that: After denitrification treatment is performed on the third flue gas at the target temperature, the method further includes: After cooling the flue gas that has been denitrated based on the boiler water preheater, second solid particles and fourth flue gas are obtained; wherein the second solid particles are discharged from the bottom of the boiler water preheater; The fourth flue gas is introduced into a chimney for discharge.

8. A method for incinerating phosphate-containing waste liquid and waste gas according to claim 7, characterized in that: The step of introducing the fourth flue gas into the chimney comprises: The fourth flue gas is introduced into a bag filter. After the fourth flue gas is processed to a preset standard in the bag filter, the fourth flue gas reaching the preset standard is introduced into a chimney based on an induced draft fan for discharge.

9. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 1, characterized in that: The initial flue gas also includes molten salt particles, and the method further includes: After the molten salt particles flow out from the bottom of the incinerator, the molten salt particles are cooled by a water cooler to obtain solid salt particles.

10. The method for incinerating phosphate-containing waste liquid and waste gas according to claim 1, characterized in that: The method further comprises: When the monitoring system detects that the combustion supply process is abnormal, the fuel supply to the incinerator is cut off; When the monitoring system detects that the gas pressure and / or wind pressure in the incineration chamber is outside a preset range, the ignition process in the incineration chamber is stopped.

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