A galvanizing continuous annealing furnace tail gas recovery and recycling device and its treatment process

Abstract

The annealing furnace tail gas recovery and treatment recycling device includes a tail gas recovery pipeline, a primary boosting system, a tail gas pretreatment system, a secondary boosting system, a deaerator, a pre-dehydration system, an adsorption drying system, a pressure regulating device, and a PLC controller connected to the power signal. The tail gas is finally connected to the annealing furnace protective gas intake main pipe after passing through the adsorption drying system and connected to the pressure regulating device. The treated tail gas is circulated for use in the galvanizing line annealing furnace. The treatment process is to remove most of the oil pollution from the tail gas generated by the furnace system after passing through the cooler; then pass through the primary boosting system to enter the tail gas pretreatment system to remove oil pollution, dust, residual ammonia, and hydrocarbon impurities in the tail gas, enter the secondary boosting system to remove oxygen; then enter the pre-dehydration system to separate water; then pass through the adsorption drying system to deeply remove water and impurity gases, and finally pass through the pressure regulating device to adjust the pressure and send it to the galvanizing line continuous annealing furnace to achieve recycling, energy saving and environmental protection.

Description

Technical Field

[0001] The invention relates to the field of annealing furnace production equipment in the metallurgical industry, and in particular to a galvanized continuous annealing furnace tail gas recovery and treatment recycling device, and also to a galvanized continuous annealing furnace tail gas recovery and treatment process. Background Art

[0002] At present, the protective gas used in the continuous annealing furnace of the galvanizing line is mainly a nitrogen-hydrogen mixture, and the tail gas is basically directly burned or discharged to the atmosphere, which not only wastes energy but is also very unsafe. The protective gas generally introduced into the continuous annealing furnace of the galvanizing line is a nitrogen-hydrogen mixture. The hydrogen content of the protective gas varies from 5% to 30%. The actual loss of this part of the protective gas during operation is only about 1% of the hydrogen content, and the rest of the protective gas is directly burned or discharged to the atmosphere. In view of this, the inventor conducted in-depth research on the above-mentioned defects in the prior art, and thus this case was created.

[0003] Therefore, it is of great significance to design and develop a device and process that can recycle most of the wasted protective gas. Summary of the invention

[0004] To solve the above technical problems, we proposed a galvanized continuous annealing furnace tail gas recovery and recycling device and its treatment process, which can reduce the amount of protective gas in the annealing furnace by more than 80%, reduce energy consumption, save costs for users, and reduce industrial tail gas emissions.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A galvanized continuous annealing furnace tail gas recovery, treatment and recycling device, comprising a tail gas recovery pipeline, a primary boosting system, a tail gas pretreatment system, a secondary boosting system, a deaerator, a pre-dehydration system, an adsorption drying system, a pressure regulating device and a PLC controller, wherein the pre-dehydration system comprises a first cooler, a condenser and a gas-water separator connected with a pipeline in the middle, the tail gas recovery pipeline and the tail gas vent pipe are connected in parallel to the annealing furnace tail gas outlet main pipe, the tail gas recovery pipeline outlet is connected to the front end of the primary boosting system, the rear end of the primary boosting system is connected to the front end of the tail gas pretreatment system, and the rear end of the tail gas pretreatment system is connected The front end of the secondary boosting system is connected, and the outlet of the secondary boosting system is connected to the deaerator. The deaerator is connected to the first cooler of the pre-dehydration system, the first cooler is connected to the condenser, the condenser is connected to the gas-water separator, the gas-water separator is connected to the adsorption drying system, and the adsorption drying system is connected to the annealing furnace protection gas inlet main pipe after being connected to the pressure regulating device, so as to be circulated by the galvanizing line annealing furnace; the PLC controller is respectively connected to the primary boosting system, the tail gas pretreatment system, the secondary boosting system, the deaerator, the pre-dehydration system, the adsorption drying system, and the pressure regulating device. A pressure transmitter and a hydrogen analyzer are arranged on the main tail gas outlet line of the annealing furnace, and regulating valves are installed on the tail gas venting line and the tail gas recovery line. The pressure transmitter and the hydrogen analyzer on the tail gas outlet main line of the annealing furnace are connected to the regulating valve through the PLC controller. The first-stage boosting system includes a second cooler, an exhaust gas collection tank, two first-stage variable frequency superchargers connected in parallel and serving as backup for each other, a buffer tank after boosting, and an overpressure exhaust pipeline. The inlet and outlet of the first-stage boosting system are provided with a cut-off valve, and are equipped with a nitrogen purge port and an exhaust port; the inlet and outlet of the first-stage variable frequency supercharger are provided with a return pipeline, and a pressure / flow regulating valve and a third cooler are installed on the return pipeline. Pressure transmitters are also provided at the inlet and outlet of the first-stage variable frequency supercharger, and a temperature transmitter is provided at the outlet of the first-stage variable frequency supercharger; the pressure transmitter and the temperature transmitter are connected to the first-stage variable frequency supercharger and the automatic control valve through a PLC controller. A venting control valve is provided on the overpressure exhaust pipeline, and the pressure transmitters at the inlet and outlet of the first-stage variable frequency supercharger are connected to the venting control valve through a PLC controller. The exhaust gas pretreatment system includes an adsorption oil removal device and a filtering dust removal and oil removal device. The adsorption oil removal device consists of two groups of oil absorbers, a heater and corresponding valves, wherein the oil absorber is equipped with a differential pressure gauge, and the oil absorber regeneration outlet pipeline is equipped with a thermal resistor. The filtering dust removal and oil removal device consists of two groups of dust removal and oil removal filters and corresponding valves, wherein the dust removal and oil removal filters are standby for each other and are equipped with a differential pressure gauge.The two-stage boosting system consists of a pre-boosting buffer tank, two two-stage variable frequency superchargers, a post-boosting oil absorber and corresponding valves, wherein the two two-stage variable frequency superchargers are connected in parallel as standby for each other, a return pipeline is set at the inlet and outlet of the two-stage variable frequency supercharger, and a pressure / flow regulating valve and a fourth cooler are installed on the return pipeline. Pressure transmitters are also set at the inlet and outlet of the two-stage variable frequency supercharger, and a temperature transmitter is set at the outlet of the two-stage variable frequency supercharger; an automatic control valve is set at the end of the two-stage boosting system, and the pressure transmitter and the temperature transmitter are connected to the two-stage variable frequency supercharger and the automatic control valve through a PLC controller. A sewage pipeline is also connected to the buffer tank of the one-stage boosting system, a sewage collecting tank is set on the sewage pipeline, and the inlet and outlet of the sewage collecting tank are respectively equipped with control valves, a safety venting device and a pressure transmitter are set at the outlet of the adsorption drying system, an automatic control valve and a pressure balancing valve are set on the venting device, and the outlet of the safety venting pipe is connected to the venting main pipe.

[0007] Preferably, the adsorption drying system comprises at least two adsorption dryers, which are filled with oil removal adsorbent, impurity removal adsorbent and water removal adsorbent; the adsorption drying system is provided with two interfaces for nitrogen regeneration and self-gas regeneration; a fifth cooler is installed on the regeneration outlet pipeline, which is then respectively connected to the front end of the dust removal and oil collection device and the safety vent, and an automatic switching valve is provided; a micro-oxygen analyzer and a dew point analyzer are installed on the outlet pipeline of the adsorption drying system; the outlet pipeline is respectively connected to the self-circulation pipeline and the pressure regulating device 1; a pressure regulating device 2 is installed on the self-circulation pipeline; the pressure regulating device 1 includes a buffer, a pressure regulating valve group, an air supply pipeline, and a pressure transmitter; an automatic air supply valve is provided on the air supply pipeline, and the pressure transmitter is connected to the automatic air supply valve through a PLC controller.

[0008] A tail gas recovery and purification circulation process for a galvanizing line annealing furnace system comprises the following steps:

[0009] The first step is to use the above-mentioned galvanizing continuous annealing furnace tail gas recovery and recycling device to cool the tail gas generated by the galvanizing line continuous annealing furnace system to below 12°C, and remove most of the oil stains in the tail gas;

[0010] In the second step, the treated exhaust gas is passed through the first-stage booster system and then enters the exhaust gas pretreatment system to further remove oil and dust in the exhaust gas, and remove impurities such as residual ammonia and hydrocarbons in the exhaust gas;

[0011] The third step is to enter the secondary boosting system for further boosting. The boosted gas first enters the deaerator to remove oxygen.

[0012] Step 4: The purified gas enters the pre-water removal system, is cooled by the cooler, condensed by the condenser, and the water is separated by the gas-water separator;

[0013] The fifth step is to use the adsorption drying system to deeply remove water and impurities from the gas, thus completing the tail gas purification process;

[0014] Step 6: The purified gas is finally sent to the galvanizing line continuous annealing furnace system after pressure regulation by a pressure regulating device for recycling.

[0015] Through the above technical scheme, the present invention utilizes the above-mentioned galvanizing continuous annealing furnace tail gas recovery and recycling device to remove most of the oil in the tail gas after the tail gas generated by the galvanizing line continuous annealing furnace system passes through the cooler; then enters the tail gas pretreatment system through the first-level supercharging system to further remove the oil and dust in the tail gas, and removes impurities such as residual ammonia and hydrocarbons in the tail gas; then enters the second-level supercharging system for supercharging again, and the supercharged gas first enters the deaerator to remove oxygen, then enters the pre-dehydration system, cools through the cooler, condenses through the condenser, and separates the water through the gas-water separator; then passes through the adsorption drying system to deeply dehydrate the gas and remove impurities, completes the tail gas purification process, and the purified gas is finally sent to the galvanizing line continuous annealing furnace system after the pressure is adjusted by the pressure regulating device to achieve recycling. In this way, the amount of protective gas used in the annealing furnace can be reduced by more than 80%, energy consumption can be reduced, cost can be saved for users, and the emission of industrial tail gas can be reduced, which can not only bring certain economic benefits to the industry, but also conform to the national policy of energy conservation and environmental protection. Thereby achieving the purpose of novel design, reasonable structure and good application effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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 these drawings without paying creative work.

[0017] Figure 1 A structural layout diagram of a galvanizing continuous annealing furnace tail gas recovery and recycling device disclosed in an embodiment of the present invention;

[0018] Figure 2 The present invention discloses a process flow chart of a tail gas recovery and purification circulation process of a galvanizing line annealing furnace system.

[0019] The numbers and letters in the figure represent the corresponding component names:

[0020] 1. Exhaust gas recovery pipeline 101. Pressure transmitter 2. First-stage boost system 21. Second cooler 22. Exhaust gas collection tank 23. First-stage variable frequency booster 24. Buffer tank after boosting 25. Overpressure emptying pipeline 26. Third cooler 27. Dirt collection tank 28. First-stage fan 3. Exhaust gas pretreatment system 31. Adsorption oil removal device 32. Filter dust removal and oil removal device 311. Oil absorber 312. Heater 321. Dust removal and oil removal filter

[0021] 4. Two-stage boost system 41. Buffer tank before boost 42. Two-stage variable frequency booster 43.

[0022] Post-boost oil suction device 44. Fourth cooler 45. Secondary fan 5. Deaerator

[0023] 6. Pre-water removal system 61. First cooler 62. Condenser 63. Gas-water separator 7.

[0024] Adsorption drying system 71. Venting device 72. Adsorption dryer 73. Fifth cooler 74. Micro oxygen analyzer 75. Dew point analyzer 8. Pressure regulating device 1 80. Pressure regulating device 2 81. Buffer 82. Pressure regulating valve group 83. Nitrogen gas supply pipe 84. Hydrogen gas supply pipe 9. PLC controller 10. Hydrogen analyzer 11. Tail gas vent pipe 12. Tail gas outlet main pipe 13. Gas distribution device 14. Pressure regulating valve station 15.

[0025] Galvanizing continuous annealing furnace DETAILED DESCRIPTION

[0026] 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.

[0027] The present invention is further described in detail below with reference to examples and specific implementation modes.

[0028] Example

[0029] like Figure 1As shown, a galvanized continuous annealing furnace tail gas recovery and recycling device includes a tail gas recovery pipeline 1, a primary boosting system 2, a tail gas pretreatment system 3, a secondary boosting system 4, a deaerator 5, a pre-dehydration system 6, an adsorption drying system 7, a pressure regulating device 8 and a PLC controller 9, wherein the pre-dehydration system 6 includes a first cooler 61, a condenser 62 and a gas-water separator 63 connected with a pipeline in the middle, the tail gas recovery pipeline 1 and the tail gas vent pipe 11 are connected in parallel to the annealing furnace tail gas outlet main pipe 12, the tail gas recovery pipeline 1 outlet is connected to the front end of the primary boosting system 2, the rear end of the primary boosting system 2 is connected to the front end of the tail gas pretreatment system 3, and the rear end of the tail gas pretreatment system 3 is connected to the The front end of the secondary boosting system 4 is connected, and the air outlet of the secondary boosting system 4 is connected to the deaerator 5. The deaerator 5 is connected to the first cooler 61 of the pre-dehydration system 6, and the first cooler 61 is connected to the condenser 62. The condenser 62 is connected to the gas-water separator 63, and the gas-water separator 63 is connected to the adsorption drying system 7. The adsorption drying system 7 is connected to the annealing furnace protective gas intake main pipe 13 after being connected to the pressure regulating device 8, so as to be circulated by the galvanizing line annealing furnace; the PLC controller 9 is respectively connected to the primary boosting system 2, the exhaust gas pretreatment system 3, the secondary boosting system 4, the deaerator 5, the pre-dehydration system 6, the adsorption drying system 7, and the pressure regulating device 8 with electrical signals.

[0030] Among them, a pressure transmitter 101 and a hydrogen analyzer 10 are arranged on the annealing furnace tail gas outlet main pipe 12, and regulating valves are installed on the tail gas venting pipe 11 and the tail gas recovery pipe 1. The pressure transmitter 101 and the hydrogen analyzer 10 on the annealing furnace tail gas outlet main pipe 12 are connected to the regulating valve through a PLC controller 9. The primary boosting system 2 includes a second cooler 21, an exhaust gas collection tank 22, two parallel primary variable frequency superchargers 23, a post-boosting buffer tank 24 and an overpressure evacuation pipeline 25. The inlet and outlet of the primary boosting system 2 are provided with a cut-off valve, a nitrogen purge port and an evacuation port; the inlet and outlet of the primary variable frequency supercharger 23 are provided with a return pipeline, a pressure / flow regulating valve and a third cooler 26 are provided on the return pipeline, and pressure transmitters are provided at the inlet and outlet of the primary variable frequency supercharger 23, and a temperature transmitter is provided at the outlet of the primary variable frequency supercharger 23; the pressure transmitter and the temperature transmitter are connected to the primary variable frequency supercharger 23 and the automatic control valve through the PLC controller 9. The overpressure evacuation pipeline 25 is provided with an evacuation control valve, and the pressure transmitters at the inlet and outlet of the primary variable frequency supercharger 23 are connected to the evacuation control valve through the PLC controller 9. The exhaust gas pretreatment system 3 includes an adsorption oil removal device 31 and a filtering dust removal and oil removal device 32. The adsorption oil removal device 31 consists of two groups of oil absorbers 311, a heater 312 and corresponding valves, wherein the oil absorber 311 is equipped with a differential pressure gauge, and the regeneration outlet pipeline of the oil absorber 311 is equipped with a thermal resistor. The filtering dust removal and oil removal device 32 consists of two groups of dust removal and oil removal filters 321 and corresponding valves, wherein the dust removal and oil removal filters 321 are standby for each other and are equipped with a differential pressure gauge. The two-stage boosting system 4 is composed of a pre-boosting buffer tank 41, two two-stage variable frequency superchargers 42, a post-boosting oil absorber 43 and corresponding valves, wherein the two two-stage variable frequency superchargers 42 are connected in parallel as backup for each other, a return pipeline is set at the inlet and outlet of the two-stage variable frequency supercharger 4, and a pressure / flow regulating valve and a fourth cooler 44 are installed on the return pipeline, and pressure transmitters are also set at the inlet and outlet of the two-stage variable frequency supercharger 42, and a temperature transmitter is set at the outlet of the two-stage variable frequency supercharger 42; an automatic control valve is set at the end of the two-stage boosting system 4, and the pressure transmitter and the temperature transmitter are connected to the two-stage variable frequency supercharger 42 and the automatic control valve through a PLC controller 9. The buffer tank 24 of the first-stage boosting system 2 is also connected to a sewage pipeline, and a sewage collecting tank 27 is arranged on the sewage pipeline. The inlet and outlet of the sewage collecting tank 27 are respectively equipped with control valves. A safety venting device 71 and a pressure transmitter are arranged at the outlet of the adsorption drying system 7. An automatic control valve and a pressure balancing valve are arranged on the venting device 71, and the outlet of the safety venting pipe is connected to the venting main pipe here.The adsorption drying system 7 comprises at least two adsorption dryers 72, and the adsorption dryers 72 are filled with oil removal adsorbent, impurity removal adsorbent and water removal adsorbent; the adsorption drying system 7 is provided with two interfaces for nitrogen regeneration and self-gas regeneration; a fifth cooler 73 is installed on the regeneration outlet pipeline, and then connected to the front end of the dust removal and oil collection device 32 and the safety vent respectively, and an automatic switching valve is provided; a micro oxygen analyzer 74 and a dew point analyzer 75 are installed on the outlet pipeline of the adsorption drying system 7; the outlet pipeline is respectively connected to the self-circulation pipeline and the pressure regulating device 8; A pressure regulating device 80 is installed on the self-circulating pipeline; the pressure regulating device 8 includes a buffer 81, a pressure regulating valve group 82, an air supply pipeline and a pressure transmitter; the air supply pipeline includes a nitrogen air supply pipe 83 and a hydrogen air supply pipe 84, and an automatic air supply valve is arranged on the air supply pipeline. Nitrogen and hydrogen respectively pass through the nitrogen air supply pipe 83 and the hydrogen air supply pipe 84 and enter the gas distribution device 13 after pressure regulation, and finally enter the galvanized continuous annealing furnace 15 through the pressure regulating valve station 14 to be reused. The pressure transmitter therein is also connected to the automatic air supply valve through the PLC controller 9.

[0031] like Figure 2 As shown, a tail gas recovery and purification cycle process of a galvanizing line annealing furnace system includes the following steps:

[0032] S1. First, the exhaust gas generated by the galvanizing line continuous annealing furnace system is cooled by a cooler using the above-mentioned exhaust gas recovery and recycling device to reduce the exhaust gas temperature to below 12°C and remove most of the oil stains in the exhaust gas;

[0033] S2, then the treated exhaust gas passes through the primary booster system and enters the exhaust gas pretreatment system to further remove oil and dust in the exhaust gas, and remove impurities such as residual ammonia and hydrocarbons in the exhaust gas;

[0034] S3, the tail gas then enters the secondary boosting system for further boosting, and the boosted gas first enters the deaerator to remove oxygen;

[0035] S4, the deoxygenated and purified gas then enters the pre-water removal system, is cooled by the cooler, condensed by the condenser, and the water is separated by the gas-water separator;

[0036] S5, then the gas is deeply dehydrated and impurity removed through the adsorption drying system to complete the tail gas purification process;

[0037] S6. The purified gas is finally sent to the galvanizing line continuous annealing furnace system after pressure regulation by a pressure regulating device for recycling.

[0038] The working principle of this technical solution is as follows: a pressure transmitter and a hydrogen analyzer 10 are set on the tail gas outlet main pipe 12 of the galvanized continuous annealing furnace 15. A control valve is set on the tail gas vent pipe 11 and the tail gas recovery pipeline 1. When the galvanized continuous annealing furnace is vented, the tail gas venting control valve is opened, the tail gas recovery control valve is closed, and the opening of the tail gas venting control valve can be automatically adjusted according to the pressure value. When the annealing furnace is recovered, the tail gas recovery control valve is opened, the tail gas venting control valve is closed, and the opening of the tail gas recovery control valve can be automatically adjusted according to the pressure value. When the system pressure reaches the upper limit, the tail gas venting control valve is opened, and the gas is vented through the tail gas venting control valve. The system can automatically choose to recover or vent according to the hydrogen content in the tail gas.

[0039] The first-stage boost system 2 can reduce the exhaust gas temperature to below 12°C through the second cooler 21 to remove most of the oil and dirt in it; the exhaust gas collection tank 22 plays a role in stabilizing the pressure, and the first-stage variable frequency booster 23 can automatically adjust the pressure before and after the fan; it also has an over-temperature alarm control, and the outlet is equipped with an automatic shut-off valve, which can be used as a safety protection when the first-stage fan 28 is started and stopped; the first-stage fan 28 bypasses the return valve, and when the inlet pressure of the first-stage fan 28 is lower than the set value, the air is returned from the outlet of the first-stage fan 28 to the inlet of the first-stage fan 28. Ensure the stable operation of the system.

[0040] The exhaust gas pretreatment system 3 can deeply remove oil, most CO2 and long-chain hydrocarbons through the adsorption oil removal device 31. There are two groups of oil absorbers 311, one group works normally and the other group regenerates. They can be automatically switched and used continuously. The regeneration of the oil absorber 311 is normally nitrogen regeneration, which can effectively discharge the oil and impurity gas in the system to the outside of the system; the inlet and outlet of the oil absorber 311 are equipped with a differential pressure gauge. When the pressure difference is large, it can remind the maintenance of the oil absorber 311 to ensure the stable operation of the adsorption oil removal device 31.

[0041] The inlet and outlet of the filter dust removal and oil removal device 32 are provided with a cut-off valve, and are equipped with a nitrogen purge port and an exhaust port. This is convenient for maintenance. A two-stage filter dust removal and oil removal device 32 is provided to remove dust and oil in the tail gas using the filtering principle.

[0042] The filtering dust removal and oil removal device 32 is provided with two sets in parallel, which are mutually standby, so as to prevent one set from breaking down or being repaired and maintained, thereby affecting the normal operation of the tail gas recovery and purification circulation device of the galvanizing continuous annealing furnace system.

[0043] The secondary boosting system 4 is provided with a secondary variable frequency booster 42, which can be automatically adjusted by the pressure before and after the secondary fan 45; it also has an over-temperature alarm control, and the outlet is equipped with an automatic cut-off valve, which can be used as a safety protection when the secondary fan 45 is started and stopped; the secondary fan 45 bypasses the return valve, and when the inlet pressure of the secondary fan 45 is lower than the set value, the air is returned from the outlet of the secondary fan 45 to the inlet of the secondary fan 45, so as to ensure the stable operation of the system.

[0044] A sewage collecting tank 27 is arranged on the sewage pipeline, and control valves are respectively installed at the inlet and outlet of the sewage collecting tank 27. A safety venting device 71 and a pressure transmitter are arranged at the outlet of the adsorption drying system 7. The venting device 71 is provided with an automatic control valve and a pressure balancing valve, and the outlet of the safety venting pipe is connected to the venting main pipe.

[0045] The adsorption drying system 7 comprises at least two adsorption dryers 72, and the adsorption dryers 72 are filled with oil removal adsorbent, impurity removal adsorbent and water removal adsorbent; the adsorption drying system 7 is provided with two interfaces for nitrogen regeneration and self-gas regeneration; a fifth cooler 73 is installed on the regeneration outlet pipeline, and then connected to the front of the secondary boosting system 4 and the safety vent respectively, and an automatic switching valve is provided; a micro-oxygen analyzer 74 and a dew point analyzer 75 are installed on the outlet pipeline of the adsorption drying system 7; the outlet pipeline is respectively connected to the self-circulation pipeline and the pressure regulating device 1 8; a pressure regulating device 2 80 is installed on the self-circulation pipeline; the pressure regulating device 1 8 comprises a buffer 81, a pressure regulating valve group 82, an air supply pipeline, a pressure transmitter, and a hydrogen analyzer 10; an automatic air supply valve is provided on the air supply pipeline, and the pressure transmitter and the hydrogen analyzer 10 are connected to the automatic air supply valve through a PLC controller 9. The adsorption drying system 7 can deeply adsorb impurity gases such as water, CO2, short-chain hydrocarbons, etc. contained in the gas, and can discharge the impurities outside the system. When the micro-oxygen analyzer 74 and the dew point analyzer 75 detect that the gas is unqualified, the gas passes through the pressure regulating device 80 to the front stage for re-purification. The pressure regulating device 8 is equipped with a buffer 81 to reduce the pressure fluctuation of the system, and has an air supply pipeline, which can automatically replenish air when the system pressure is low to ensure the gas supply pressure; it is equipped with a self-operated pressure regulating valve to adjust the air intake pressure of the galvanizing continuous annealing furnace.

[0046] In this example, the present invention utilizes the above-mentioned galvanizing continuous annealing furnace tail gas recovery and recycling device to remove most of the oil in the tail gas after the tail gas generated by the galvanizing line continuous annealing furnace system passes through the cooler; then enters the tail gas pretreatment system through the first-level supercharging system to further remove the oil and dust in the tail gas, and removes impurities such as residual ammonia and hydrocarbons in the tail gas; then enters the second-level supercharging system for supercharging again, and the supercharged gas first enters the deaerator to remove oxygen, then enters the pre-dehydration system, cools through the cooler, condenses through the condenser, and separates the water through the gas-water separator; then passes through the adsorption drying system to deeply dehydrate the gas and remove impurities, completes the tail gas purification process, and the purified gas is finally sent to the galvanizing line continuous annealing furnace system after the pressure is adjusted by the pressure regulating device to achieve recycling. In this way, the amount of protective gas used in the annealing furnace can be reduced by more than 80%, energy consumption can be reduced, cost can be saved for users, and the emission of industrial tail gas can be reduced, which can not only bring certain economic benefits to the industry, but also conform to the national policy of energy conservation and environmental protection. Thereby achieving the purpose of novel design, reasonable structure and good application effect.

[0047] The above is only a preferred implementation scheme of a galvanized continuous annealing furnace tail gas recovery, treatment and recycling device and its treatment process of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A galvanizing continuous annealing furnace tail gas recovery and recycling device, characterized in that: The invention comprises an exhaust gas recovery pipeline, a primary supercharging system, an exhaust gas pretreatment system, a secondary supercharging system, a deaerator, a pre-dehydration system, an adsorption drying system, a pressure regulating device and a PLC controller. The pre-dehydration system comprises a first cooler, a condenser and a gas-water separator connected with pipelines in the middle. The exhaust gas recovery pipeline and the exhaust gas vent pipe are connected in parallel to the exhaust gas outlet main pipe of the annealing furnace. The outlet of the exhaust gas recovery pipeline is connected to the front end of the primary supercharging system, the rear end of the primary supercharging system is connected to the front end of the exhaust gas pretreatment system, and the rear end of the exhaust gas pretreatment system is connected to the front end of the secondary supercharging system. The air outlet of the secondary boosting system is connected to the deaerator, the deaerator is connected to the first cooler of the pre-dehydration system, the first cooler is connected to the condenser, the condenser is connected to the gas-water separator, the gas-water separator is connected to the adsorption drying system, the adsorption drying system is connected to the annealing furnace protection gas inlet main pipe after being connected to the pressure regulating device, and is circulated by the galvanizing line annealing furnace; the PLC controller is respectively connected to the first-stage boosting system, the tail gas pretreatment system, the secondary boosting system, the deaerator, the pre-dehydration system, the adsorption drying system, and the pressure regulating device. A pressure transmitter and a hydrogen analyzer are provided on the main pipe of the tail gas outlet of the annealing furnace, and regulating valves are installed on the tail gas venting pipe and the tail gas recovery pipe. The pressure transmitter and the hydrogen analyzer on the main pipe of the tail gas outlet of the annealing furnace are connected to the regulating valve through a PLC controller; The first-stage boosting system includes a second cooler, an exhaust gas collection tank, two first-stage variable frequency superchargers connected in parallel and serving as backup for each other, a buffer tank after boosting, and an overpressure exhaust pipeline. The inlet and outlet of the first-stage boosting system are provided with a cut-off valve, and are equipped with a nitrogen purge port and an exhaust port; the inlet and outlet of the first-stage variable frequency supercharger are provided with a reflux pipeline, and a pressure / flow regulating valve and a third cooler are installed on the reflux pipeline. Pressure transmitters are also provided at the inlet and outlet of the first-stage variable frequency supercharger, and a temperature transmitter is provided at the outlet of the first-stage variable frequency supercharger; the pressure transmitter and the temperature transmitter are connected to the first-stage variable frequency supercharger and the automatic control valve through a PLC controller through electrical signals; The overpressure exhaust pipeline is provided with an exhaust control valve, and the pressure transmitters at the inlet and outlet of the first-stage variable frequency booster are connected to the exhaust control valve electrical signal through the PLC controller; The exhaust gas pretreatment system comprises an adsorption oil removal device and a filtering dust removal oil removal device. The adsorption oil removal device consists of two groups of oil absorbers, a heater and corresponding valves, wherein the oil absorber is equipped with a differential pressure gauge, and the regeneration outlet pipeline of the oil absorber is equipped with a thermal resistor. The filtering dust removal oil removal device consists of two groups of dust removal and oil removal filters and corresponding valves, wherein the dust removal and oil removal filters are standby for each other and are equipped with a differential pressure gauge; The two-stage boosting system consists of a pre-boosting buffer tank, two two-stage variable frequency superchargers, a post-boosting oil absorber and corresponding valves, wherein the two two-stage variable frequency superchargers are connected in parallel as standby for each other, a return pipeline is arranged at the inlet and outlet of the two-stage variable frequency supercharger, a pressure / flow regulating valve and a fourth cooler are installed on the return pipeline, pressure transmitters are also arranged at the inlet and outlet of the two-stage variable frequency supercharger, and a temperature transmitter is arranged at the outlet of the two-stage variable frequency supercharger; an automatic control valve is arranged at the end of the two-stage boosting system, and the pressure transmitter and the temperature transmitter are connected to the two-stage variable frequency supercharger and the automatic control valve through a PLC controller; a sewage pipeline is also connected to the buffer tank of the one-stage boosting system, a sewage collecting tank is arranged on the sewage pipeline, and control valves are installed at the inlet and outlet of the sewage collecting tank, a safety venting device and a pressure transmitter are arranged at the outlet of the adsorption drying system, an automatic control valve and a pressure balancing valve are arranged on the venting device, and the outlet of the safety venting pipe is connected to the venting main pipe.

2. The tail gas recovery and recycling device of a galvanized continuous annealing furnace according to claim 1 is characterized in that: The adsorption drying system comprises at least two adsorption dryers, in which oil removal adsorbent, impurity removal adsorbent and water removal adsorbent are installed; the adsorption drying system is provided with two interfaces of nitrogen regeneration and self-gas regeneration; a fifth cooler is installed on the regeneration gas outlet pipeline, which is then respectively connected to the front end of the dust removal and oil collection device and the safety vent, and an automatic switching valve is provided; a micro-oxygen analyzer and a dew point analyzer are installed on the outlet pipeline of the adsorption drying system; the gas outlet pipeline is respectively connected to the self-circulation pipeline and the pressure regulating device 1; a pressure regulating device 2 is installed on the self-circulation pipeline; the pressure regulating device 1 comprises a buffer, a pressure regulating valve group, an air supply pipeline and a pressure transmitter; an automatic air supply valve is provided on the air supply pipeline, and the pressure transmitter is connected to the automatic air supply valve through a PLC controller.

3. A tail gas recovery and purification cycle process for a galvanizing line annealing furnace system, characterized in that: The following steps are involved: The first step is to use the exhaust gas recovery and recycling device of the galvanizing continuous annealing furnace as claimed in claim 2 to cool the exhaust gas generated by the galvanizing line continuous annealing furnace system to below 12° C. and remove most of the oil stains in the exhaust gas; In the second step, the treated exhaust gas is passed through a primary booster system and then enters an exhaust gas pretreatment system to further remove oil and dust in the exhaust gas, and to remove residual ammonia and hydrocarbon impurities in the exhaust gas; The third step is to enter the secondary boosting system for further boosting. The boosted gas first enters the deaerator to remove oxygen. In the third step, the purified gas enters the pre-water removal system, is cooled by the cooler, condensed by the condenser, and the water is separated by the gas-water separator; The fourth step is to use the adsorption drying system to deeply remove water and impurities from the gas, thus completing the tail gas purification process; Step 5: The purified gas is finally sent to the galvanizing line continuous annealing furnace system after pressure regulation by a pressure regulating device for recycling.

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