System for feeding tail gas of waste gas back distribution and dry quenching pre-storage section into coke oven for incineration

Abstract

The utility model relates to a system for feeding tail gas of a waste gas return distribution and dry quenching pre-storage section into a coke oven for incineration. The system comprises a fan and an air shutter, a dust removal assembly for treating dry quenching tail gas and a gas adjusting assembly are further arranged at an inlet of the fan so as to carry out environment dust removal and gas amount adjustment; a certain amount of coke oven chimney gas or dry quenching pre-storage section diffused tail gas is fed into an air shutter by a fan and is uniformly mixed into coke oven combustion-supporting air, so that the oxygen concentration in the combustion-supporting air per unit volume is obviously reduced (generally about 18%), the temperature of a combustion point is reduced, and the combustion efficiency is improved. The device has the effects of inhibiting the concentration of nitric oxide in flue gas, lengthening flame, reducing the temperature difference between the upper part and the lower part of the carbonization chamber and the like, and a waste gas return and distribution technology not only can well reduce the concentration of NOx in the flue gas, but also can well improve the high-direction heating of the coke oven.

Description

Technical Field

[0001] The utility model relates to the technical field of tail gas circulation treatment, in particular to a waste gas recycling and dry coke quenching pre-storage section tail gas feeding coke oven incineration system. Background Art

[0002] Coke oven dry quenching (CDQ) is a quenching technology widely used in steel companies. It uses an inert gas (such as nitrogen) to cool red-hot coke, replacing the traditional wet quenching method. During the CDQ process, red-hot coke is pushed out of the coke oven and into the CDQ furnace. A circulating fan blows inert gas (such as nitrogen) into the CDQ furnace's cooling chamber, where it comes into countercurrent contact with the coke, absorbing the coke's sensible heat and cooling it to below 200°C. The hot inert gas then enters the CDQ boiler, exchanging heat with the boiler water to generate steam. The cooled inert gas is then recirculated back into the CDQ furnace by the circulating fan.

[0003] The CO concentration in the exhaust gas emitted from the pre-storage section of the dry coke quenching process of the coke oven often seriously exceeds the standard, mainly due to the following reasons: 1) Incomplete combustion: During the dry coke quenching process, if the combustion is incomplete, the CO content in the exhaust gas will increase; 2) System leakage: Equipment leakage or improper operation may cause air to enter the dry coke quenching system and react with the CO in the circulating gas, but it may also cause new incomplete combustion due to the entry of oxygen to produce more CO; 3) Gas circulation and regulation problems: Improper regulation of the circulating gas, such as unreasonable settings of the position of the air inlet and outlet, gas flow rate, air flow rate, etc., may also cause the CO concentration to exceed the standard.

[0004] On the other hand, coke ovens have a problem with high-level heating, primarily due to the following reasons: 1) Gas combustion rate. When the gas combustion rate is too fast, the flame is short, which may lead to insufficient heating of the upper part of the coke oven. When the combustion rate is too slow, although the flame is elongated, it may also cause the lower part to overheat and the upper part to be insufficiently heated. 2) Airflow velocity. If the airflow velocity is too fast, it may lead to uneven heat transfer, resulting in a low temperature in the upper part of the coke oven. However, if the airflow velocity is too slow, it may lead to high temperature in the lower part. 3) Heat transfer from the furnace wall. Factors such as the thermal conductivity and thickness of the furnace wall material and the shape of the vertical fireway partition all affect heat transfer and distribution. If the furnace wall has poor heat transfer performance, the upper part of the coke oven may be too cold, while the lower part may be too hot.

[0005] Therefore, how to release the tail gas from the CDQ pre-storage stage to improve the high-direction heating of the coke oven while reducing the CO concentration has become a technical problem that needs to be solved by those skilled in the art. Utility Model Content

[0006] The utility model provides a waste gas recirculation and CDQ pre-storage section tail gas feeding coke oven incineration system to solve the technical problems of high CO concentration in the CDQ pre-storage section tail gas and poor high-direction heating effect of the coke oven in the prior art.

[0007] In order to solve the above problems, the waste gas recycling and CDQ pre-storage section tail gas feeding coke oven incineration system provided by the present invention adopts the following technical solutions:

[0008] A waste gas recirculation and dry coke quenching pre-storage section tail gas feeding coke oven incineration system includes a fan and an air switch. The fan is used to send the dry coke quenching tail gas into the air switch. The air switch is used to mix the dry coke quenching tail gas into the coke oven combustion-supporting air to improve the high-direction heating of the coke oven. The fan inlet is also provided with a dust removal component and a gas regulation component for processing the dry coke quenching tail gas to perform environmental dust removal and gas volume regulation.

[0009] The beneficial effects of the technology of the present invention are as follows: by mixing the dry coke quenching tail gas into the coke oven combustion-supporting gas, it replaces the circulating waste gas to enter the coke oven, and at the same time achieves zero emission of CO in the discharged tail gas, improves the high-direction heating of the coke oven, reduces the heating gas consumption and the NOx (nitrogen oxides) emission of the chimney gas, and through the dust removal component and the gas regulation component, it can control the dry coke quenching tail gas to a certain concentration, ensuring that it is lower than the safety control index after mixing with the coke oven combustion-supporting air, effectively solving the technical problems of high CO concentration in the discharged tail gas of the dry coke quenching pre-storage stage and poor high-direction heating effect of the coke oven in the prior art.

[0010] Furthermore, a manual butterfly valve is provided at the outlet of the blower, and the manual butterfly valve is used to disconnect the connection between the blower and the air switch during maintenance.

[0011] Furthermore, a main pipeline is arranged at the outlet of the fan, the manual butterfly valve is installed on the main pipeline, the main pipeline is provided with an expansion joint to prevent pipeline damage caused by thermal expansion and contraction, there are multiple air switches, and multiple branch pipelines are installed on the main pipeline, each branch pipeline is connected to an air switch, and each branch pipeline has a reversing valve structure, a metal hose and a manual regulating valve.

[0012] Furthermore, the reversing valve structure includes a reversing valve, a reversing pull rod, an electro-hydraulic push rod and a counterweight, and the reversing valve structure is interlocked with the air reversing mechanism of the coke oven for control.

[0013] Furthermore, the blower inlet has two air intake branches, which are defined as a first air intake branch and a second air intake branch. The first air intake branch is used to introduce dry quenching tail gas, and the second air intake branch is used to introduce coke oven chimney gas.

[0014] Furthermore, the first air inlet branch pipe includes two branch pipes, one of which is provided with a first pneumatic regulating valve, which is used to adjust the amount of dust released according to the amount of waste gas returned from the coke oven, and the gas regulating assembly includes the first pneumatic regulating valve;

[0015] Another branch pipe is connected to the inlet of the fan through a bag dust collector and an exhaust gas recirculation machine, and a pneumatic quick-cut valve, a first flow meter and a CO online analyzer are installed on the branch pipe. The pneumatic quick-cut valve is used for safety cutting off, and the dust removal component is the above-mentioned bag dust collector.

[0016] Furthermore, the second air intake branch pipe is provided with a second pneumatic regulating valve, and the gas regulating assembly includes the second pneumatic regulating valve.

[0017] Furthermore, the main pipeline is provided with a second flow meter, and the second flow meter is located between the fan and the manual butterfly valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0019] Figure 1 This is a schematic diagram of the waste gas recycling and CDQ pre-storage section tail gas feeding into the coke oven incineration system provided by the present invention.

[0020] Description of reference numerals:

[0021] 1. Fan; 2. Air switch; 3. Manual butterfly valve; 4. Main pipeline; 5. Branch pipeline; 6. Metal hose; 8. Reversing valve; 9. Electro-hydraulic push rod; 10. Counterweight; 11. First air inlet branch; 12. Second air inlet branch; 13. First pneumatic control valve; 14. Bag dust collector; 15. Pneumatic quick-cut valve; 16. First flow meter; 17. Second pneumatic control valve; 18. Second flow meter. DETAILED DESCRIPTION

[0022] 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. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0023] It should be noted that the main idea of ​​the present invention is to mix the dry coke quenching tail gas into the coke oven combustion-supporting gas so that it replaces the circulating waste gas in entering the coke oven, thereby achieving zero emission of CO in the discharged tail gas and improving the high-direction heating of the coke oven, reducing the heating gas consumption and the NOx (nitrogen oxides) emission of the chimney gas. Moreover, through the dust removal component and the gas regulation component, the dry coke quenching tail gas can be controlled at a certain concentration to ensure that it is lower than the safety control index after mixing with the coke oven combustion-supporting air, so as to solve the technical problems of high CO concentration in the discharged tail gas of the dry coke quenching pre-storage section and poor high-direction heating effect of the coke oven in the prior art.

[0024] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention are described in detail below. The numbers of any elements in the drawings are for illustration only and not for limitation, and any names are for distinction only and do not have any limiting meaning.

[0025] The principle and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0026] Example 1 of the waste gas recycling and CDQ pre-storage section tail gas feeding coke oven incineration system provided by the utility model:

[0027] like Figure 1 As shown, the exhaust gas recirculation and CDQ pre-storage section tail gas feeding into the coke oven incineration system includes a fan 1 and an air switch 2, wherein the fan 1 is used to send the CDQ tail gas into the air switch 2, and the air switch 2 is used to mix the CDQ tail gas into the coke oven combustion-supporting air to improve the high-directional heating of the coke oven; the fan 1 inlet is also provided with a dust removal component and a gas regulation component for treating the CDQ tail gas to perform environmental dust removal and gas volume regulation.

[0028] In order to facilitate maintenance, a manual butterfly valve 3 is provided at the outlet of the fan 1, and the manual butterfly valve 3 is used to disconnect the connection between the fan 1 and the air switch 2 during maintenance.

[0029] Regarding the connection between the fan 1 and the air switch 2. A main pipe 4 is arranged at the outlet of the fan 1, and the manual butterfly valve 3 is installed on the main pipe 4. The main pipe 4 has an expansion joint to prevent pipe damage caused by thermal expansion and contraction. There are multiple air switches 2. Multiple branch pipes 5 are installed on the main pipe 4. Each branch pipe 5 is connected to an air switch 2. Each branch pipe 5 has a reversing valve structure, a metal hose 6 and a manual regulating valve.

[0030] Specifically, the reversing valve structure includes a reversing valve 8, a reversing pull rod, an electro-hydraulic push rod 9 and a counterweight 10, and the reversing valve structure is interlocked with the air reversing mechanism of the coke oven for control.

[0031] Regarding the inlet of the fan 1. The inlet of the fan 1 has two air intake branches, which are defined as a first air intake branch 11 and a second air intake branch 12. The first air intake branch 11 is used to introduce the dry quenching exhaust gas, and the second air intake branch 12 is used to introduce the coke oven chimney gas.

[0032] First, let's introduce the first air intake branch pipe 11. The first air intake branch pipe 11 includes two branch pipes, one of which is installed with a first pneumatic regulating valve 13. The first pneumatic regulating valve 13 is used to adjust the dust emission according to the required amount of waste gas returned from the coke oven. The gas regulating assembly includes the first pneumatic regulating valve 13.

[0033] Another branch pipe is connected to the inlet of the fan 1 through a bag dust collector 14 and an exhaust gas recirculation machine, and a pneumatic quick-cut valve 15, a first flow meter 16 and a CO online analyzer are installed on the branch pipe. The pneumatic quick-cut valve 15 is used for safety cut-off, and the dust removal component is the above-mentioned bag dust collector 14.

[0034] The second air intake branch pipe 12 is described below. The second air intake branch pipe 12 is provided with a second pneumatic regulating valve 17 , and the gas regulating assembly includes the second pneumatic regulating valve 17 .

[0035] Finally, the main pipeline 4 is further provided with a second flow meter 18 , which is located between the fan 1 and the manual butterfly valve 3 .

[0036] A certain amount of coke oven chimney gas or exhaust gas from the CDQ pre-storage section is sent into the air switch by a fan and evenly mixed into the coke oven combustion-supporting air. The oxygen concentration per unit volume of combustion-supporting air is significantly reduced (generally around 18%), which reduces the combustion point temperature. It has the effects of suppressing the concentration of nitrogen oxides in the flue gas, lengthening the flame, and reducing the temperature difference between the upper and lower parts of the carbonization chamber. Therefore, the waste gas recirculation technology can not only effectively reduce the NOx concentration in the flue gas, but also effectively improve the high-directional heating of the coke oven.

[0037] When used to release tail gas from the coke quenching pre-storage section to replace chimney gas, the combustible components or oxygen in the tail gas must be controlled within a certain concentration to ensure that it is lower than the safety control index after mixing with the coke oven combustion air.

[0038] The waste gas re-matching and dry quenching pre-storage section tail gas feeding into the coke oven incineration system provided by the present invention is in operation: when the monitoring data of the first flow meter 16 is greater than the waste gas re-matching requirement, the pressure before the bag filter 14 is reduced, the first pneumatic regulating valve 13 is opened to an appropriate degree, and the excess part enters the environmental dust collector. At this time, the waste gas re-matching adopts the dry quenching pre-storage section to release the tail gas;.

[0039] When the monitoring data of the first flow meter 16 is less than the waste gas return need, the pressure in front of the bag filter 14 is reduced, and the second pneumatic regulating valve 17 is opened to an appropriate degree to supplement the insufficient part with the chimney waste gas. Since the pre-stored section exhaust gas flow rate when the CDQ furnace is loaded with coke is much larger than when it is not loaded with coke, the exhaust gas flow rate at this time can meet (or exceed) the coke oven exhaust gas return need, while when it is not loaded with coke, it is less than the coke oven exhaust gas return need, and some chimney gas needs to be supplemented. The amount of gas supplied to the chimney is automatically calculated and matched by the system based on parameters such as the pre-stored section exhaust gas flow rate (first flow meter 16), the exhaust gas CO concentration, and the coke oven exhaust gas return need (second flow meter 18);

[0040] When the CO concentration exceeds the set value (CO concentration in the shutter reaches 50% LEL), the system automatically discharges part of the exhaust gas into the CDQ environmental dust collector and automatically introduces some chimney gas. When the CO concentration exceeds the set upper limit (i.e., the CO concentration in the shutter is still above 50% LEL after the chimney gas is introduced), the system automatically cuts off the pre-stored exhaust gas transmission pipeline, and the exhaust gas required for the exhaust gas re-distribution is entirely coke oven chimney gas.

[0041] Example 2 of the waste gas recycling and CDQ pre-storage section tail gas feeding coke oven incineration system provided by the utility model:

[0042] The main difference between it and Example 1 is:

[0043] In Example 1, there are two air intake branches at the fan inlet, which are defined as a first air intake branch 11 and a second air intake branch 12. The first air intake branch 11 is used to introduce dry coke quenching exhaust gas, and the second air intake branch 12 is used to introduce coke oven chimney gas from the coke oven chimney.

[0044] In this embodiment, only one air intake branch pipe is provided at the inlet of the blower for introducing the CDQ tail gas.

[0045] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "width", "horizontal", "top", "bottom", "inside", "outside" and other terms indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings of this specification. They are only for the purpose of facilitating the explanation of the scheme of the utility model and simplifying the description, rather than explicitly or implicitly indicating that the devices or elements involved must have the specific orientation, be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the utility model.

[0046] In addition, in the description of this specification, “a plurality of” means at least two, for example, two, three or more, etc., unless otherwise clearly and specifically defined.

Claims

1. A waste gas recycling and dry quenching pre-storage section tail gas feeding coke oven incineration system, characterized in that: It includes a fan and an air switch. The fan is used to send the CDQ exhaust gas into the air switch, and the air switch is used to mix the CDQ exhaust gas into the coke oven combustion-supporting air to improve the high-directional heating of the coke oven. The fan inlet is also equipped with a dust removal component and a gas regulation component for processing the CDQ exhaust gas to perform environmental dust removal and gas volume regulation.

2. The exhaust gas recycling and CDQ pre-storage tail gas feeding coke oven incineration system according to claim 1 is characterized in that: The blower outlet is provided with a manual butterfly valve, which is used to disconnect the blower from the air switch during maintenance.

3. The exhaust gas recycling and CDQ pre-storage tail gas feeding coke oven incineration system according to claim 2 is characterized in that: A main pipeline is arranged at the outlet of the fan, and the manual butterfly valve is installed on the main pipeline. The main pipeline is provided with an expansion joint to prevent pipeline damage caused by thermal expansion and contraction. There are multiple air switches, and multiple branch pipelines are installed on the main pipeline. Each branch pipeline is connected to an air switch, and each branch pipeline has a reversing valve structure, a metal hose and a manual regulating valve.

4. The exhaust gas recycling and CDQ pre-storage tail gas feeding coke oven incineration system according to claim 3 is characterized in that: The reversing valve structure comprises a reversing valve, a reversing pull bar, an electro-hydraulic push rod and a counterweight, and the reversing valve structure is interlocked with the air reversing mechanism of the coke oven for control.

5. The exhaust gas recycling and CDQ pre-storage tail gas feeding coke oven incineration system according to any one of claims 1 to 4, characterized in that: The blower inlet is provided with two air inlet branches, which are defined as a first air inlet branch and a second air inlet branch respectively. The first air inlet branch is used for introducing dry coke quenching tail gas, and the second air inlet branch is used for introducing coke oven chimney gas from the coke oven chimney.

6. The exhaust gas recycling and CDQ pre-storage tail gas feeding coke oven incineration system according to claim 5 is characterized in that: The first air inlet branch pipe includes two branch pipes, one of which is equipped with a first pneumatic regulating valve, which is used to adjust the amount of dust released according to the amount of waste gas returned from the coke oven. The gas regulating assembly includes the first pneumatic regulating valve. Another branch pipe is connected to the inlet of the fan through a bag dust collector and an exhaust gas recirculation machine, and a pneumatic quick-cut valve, a first flow meter and a CO online analyzer are installed on the branch pipe. The pneumatic quick-cut valve is used for safety cutting off, and the dust removal component is the above-mentioned bag dust collector.

7. The exhaust gas recycling and CDQ pre-storage tail gas feeding coke oven incineration system according to claim 6 is characterized in that: The second air intake branch pipe is provided with a second pneumatic regulating valve, and the gas regulating assembly includes the second pneumatic regulating valve.

8. The exhaust gas recycling and CDQ pre-storage tail gas feeding coke oven incineration system according to claim 3 or 4 is characterized in that: The main pipeline is also provided with a second flow meter, which is located between the fan and the manual butterfly valve.

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