Hydrogen halide waste gas treatment method and device

Abstract

The invention relates to the technical field of waste gas treatment, in particular to a hydrogen halide waste gas treatment method and device. The method comprises the following steps: carrying out first impurity removal on the hydrogen halide waste gas by using alkali liquor in a multi-stage spraying manner to obtain first fly ash and first hydrogen halide waste gas; performing secondary impurity removal on the first hydrogen halide waste gas by adopting an alkaline material to obtain second fly ash and second hydrogen halide waste gas; the second hydrogen halide waste gas is incinerated and then subjected to staged cooling, and third fly ash and target hydrogen halide waste gas are obtained; wherein the target hydrogen halide waste gas has a target final cooling temperature; the first fly ash, the second fly ash and the third fly ash are respectively subjected to gravity settling and then are collected. The technical problem that an existing hydrogen halide waste gas treatment process is not beneficial to environmental protection is solved, so that the service life of equipment is prolonged, the investment cost is saved, and secondary pollution generated in the waste gas treatment process is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of waste gas treatment, and in particular to a method and device for treating hydrogen halide waste gas. Background Art

[0002] With the national development strategy planning, the requirements for environmental protection are becoming increasingly stringent. In traditional treatment projects containing high-temperature and high-concentration hydrogen halide waste gas, high-temperature combustion combined with rapid cooling and alkaline washing technology is usually used. However, the current treatment methods for hydrogen halide waste gas are not conducive to environmental protection. Summary of the invention

[0003] The present application provides a method and device for treating hydrogen halide waste gas to solve the technical problem that the existing hydrogen halide waste gas treatment process is not environmentally friendly.

[0004] In a first aspect, the present application provides a method for treating hydrogen halide waste gas, the method comprising:

[0005] Using alkali solution and performing a first impurity removal on the hydrogen halide waste gas by a multi-stage spraying method to obtain a first fly ash and a first hydrogen halide waste gas;

[0006] Performing a second impurity removal on the first hydrogen halide waste gas by using an alkaline material to obtain second fly ash and second hydrogen halide waste gas;

[0007] The second hydrogen halide waste gas is incinerated and then cooled in stages to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature; the first fly ash, the second fly ash and the third fly ash are respectively collected after gravity sedimentation.

[0008] Optionally, the alkaline material includes at least one of the following: sodium hydroxide and calcium oxide.

[0009] Optionally, the target final cooling temperature is 200-280°C.

[0010] Optionally, the second hydrogen halide waste gas is incinerated and then cooled in stages to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature, comprising:

[0011] Incinerating the second hydrogen halide waste gas, and then performing a first cooling;

[0012] Under the condition of a set cooling rate, the second hydrogen halide waste gas after the first cooling is subjected to a second cooling to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature.

[0013] Optionally, the initial temperature of the first cooling is 800-1100°C, and the end temperature of the first cooling is 300-500°C.

[0014] Optionally, the set cooling rate is 80-100°C / s.

[0015] In a second aspect, the present application provides a device for treating hydrogen halide waste gas, the device comprising:

[0016] A multi-stage alkaline solution spraying device, used for first removing impurities from the hydrogen halide waste gas;

[0017] an incineration device, used for incinerating the second hydrogen halide waste gas, and connected to the alkali solution multi-stage spraying device;

[0018] A first cooling device, used for first cooling the second hydrogen halide waste gas after the incineration, and connected to the incineration device;

[0019] A second cooling device, used for performing a second cooling on the second hydrogen halide waste gas after incineration, and connected to the first cooling device;

[0020] A first ash hopper, used for collecting first fly ash, and connected to the alkali solution multi-stage spraying device;

[0021] The second ash hopper is used to collect the second fly ash and the third fly ash and is connected to the incineration device.

[0022] Optionally, the device further comprises:

[0023] Alkali liquid storage and transportation device; the alkali liquid storage and transportation device comprises:

[0024] A lye storage device, used for storing lye;

[0025] The alkali solution conveying device is used for conveying the alkali solution and is connected with the alkali solution storage device.

[0026] Optionally, the device further comprises:

[0027] A third cooling device, used for performing a third cooling on the target hydrogen halide waste gas, and connected to the second cooling device;

[0028] A smoke exhaust fan, used for conveying the target hydrogen halide waste gas after the third cooling; connected to the third cooling device;

[0029] A chimney is used to discharge the target hydrogen halide waste gas after the third cooling and is connected to the smoke exhaust fan.

[0030] Optionally, both the first cooling device and the third cooling device are heat exchange devices.

[0031] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0032] The method for treating the hydrogen halide waste gas provided in the embodiment of the present application uses alkaline solution and multi-stage spraying to treat the hydrogen halide waste gas, thereby improving the efficiency of dehydrohalogenation in the waste gas before incineration; the fly ash is subjected to natural gravity sedimentation respectively, thereby reducing the fly ash being carried into the subsequent incineration treatment section by the waste gas; in order to further reduce the halides in the waste gas entering the incineration treatment, the injection of alkaline materials is increased before the waste gas enters the incineration treatment. The final cooling temperature of the second cooling is controlled to reduce the generation of dioxins. In summary, the method is beneficial to environmental protection. In addition, the method reduces the corrosiveness of high-concentration hydrogen halide waste gas to equipment, extends the service life of the equipment, and saves investment costs; it avoids the generation of secondary waste gas, wastewater and waste liquid in the waste gas treatment process, which causes environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0034] In order to more clearly illustrate the embodiments of the present application 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A schematic flow chart of a method for treating hydrogen halide waste gas provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of the structure of a hydrogen halide waste gas treatment device provided in an embodiment of the present application; wherein:

[0037] 1-alkaline solution multi-stage spraying device, 2-incineration device, 3-first cooling device, 4-second cooling device, 5-first ash hopper, 6-first ash hopper, 7-alkaline solution storage and transportation device, 71-alkaline solution storage and transportation device, 72-alkaline solution conveying device, 8-third cooling device, 9-smoke exhaust fan, 10-chimney. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0039] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0040] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0041] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0042] In the first aspect, the present application provides a method for treating hydrogen halide waste gas, see Figure 1 , the method comprising:

[0043] The treatment method of the hydrogen halide waste gas provided in the embodiment of the present application uses alkaline solution and multi-stage spraying to treat the hydrogen halide waste gas, thereby improving the efficiency of dehydrohalogenation in the waste gas before incineration; the fly ash is subjected to natural gravity sedimentation, thereby reducing the fly ash being carried into the subsequent incineration treatment section by the waste gas; in order to further reduce the halides in the waste gas entering the incineration treatment, the injection of alkaline materials is increased before the waste gas enters the incineration treatment. The final cooling temperature of the second cooling is controlled to reduce the generation of dioxins.

[0044] S1. Using alkali solution and performing a first impurity removal on the hydrogen halide waste gas by a multi-stage spraying method to obtain a first fly ash and a first hydrogen halide waste gas;

[0045] In the embodiment of the present application, the temperature of the above-mentioned hydrogen halide waste gas is 450°C to 500°C, and the content of hydrogen halide in the hydrogen halide waste gas is 5 to 15% by weight. The above-mentioned alkali solution can be an alkaline earth metal oxide; the positive effect of adopting the multi-stage spraying method is that the hydrogen halide waste gas and the alkali solution undergo a neutralization reaction in stages, and as much hydrogen halide, sulfide, etc. as possible are removed. If the multi-stage spraying method is not adopted, it will lead to an increase in investment in downstream treatment facilities to a certain extent, and the final waste gas emission will not meet the standards.

[0046] S2. performing a second impurity removal on the first hydrogen halide waste gas using an alkaline material to obtain second fly ash and a second hydrogen halide waste gas;

[0047] In some embodiments, the alkaline material includes at least one of the following: sodium hydroxide, calcium oxide.

[0048] The positive effect of using sodium hydroxide and calcium oxide as the alkaline materials is to further react and remove a small amount of halides carried in the exhaust gas, mainly to ensure that the generated solid dust particles do not cause secondary pollution. In this process, when the temperature is reduced to a certain level, activated carbon can also be added, the purpose of which is to absorb some unreacted hydrogen halides and possible dioxins.

[0049] S3. The second hydrogen halide waste gas is incinerated, and then cooled in stages to obtain a third fly ash and a target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature; the first fly ash, the second fly ash and the third fly ash are collected after gravity sedimentation.

[0050] In some embodiments, the target final cooling temperature is 200-280°C.

[0051] The positive effects of controlling the final cooling temperature of the target hydrogen halide waste gas to 200-280°C are: further solving the nitrogen oxides that may exist in the waste gas and creating temperature conditions for the denitration catalyst; if the final cooling temperature is too high, the denitration efficiency will be reduced to a certain extent; if the final cooling temperature is too low, the denitration efficiency of the catalyst will be reduced to a certain extent. Specifically, the final cooling temperature can be 200°C, 220°C, 240°C, 260°C, 280°C, etc.

[0052] In some embodiments, the second hydrogen halide waste gas is incinerated and then cooled in stages to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature, comprising:

[0053] Incinerating the second hydrogen halide waste gas, and then performing a first cooling;

[0054] Under the condition of a set cooling rate, the second hydrogen halide waste gas after the first cooling is subjected to a second cooling to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature.

[0055] In some embodiments, the initial temperature of the first cooling is 800-1100°C, and the end temperature of the first cooling is 300-500°C.

[0056] The positive effect of controlling the initial temperature of the first cooling to 800-1100°C is to ensure that the organic matter is fully burned and decomposed in the secondary combustion chamber. If the temperature is too high, it will cause damage to the secondary combustion chamber to a certain extent, and will also increase the investment cost; if the temperature is too low, it will not be able to completely decompose the organic matter to a certain extent, resulting in substandard emissions. Specifically, the final cooling temperature can be 800°C, 900°C, 1000°C, 1100°C, etc. The positive effect of controlling the end temperature of the first cooling to 300-500°C is to control the temperature below 300°C as much as possible, thereby reducing the secondary generation of dioxins, and at the same time recover more heat and produce more steam as a byproduct. If the temperature is too high, it will cause energy loss and waste to a certain extent; if the temperature is too low, it will not be possible to obtain more high-quality steam to a certain extent. Specifically, the final cooling temperature can be 300°C, 400°C, 500°C, etc. This step will generate high-temperature exhaust gas for waste heat recovery.

[0057] In some embodiments, the set cooling rate is 80-100° C. / s.

[0058] The positive effect of controlling the cooling rate of the second cooling to 80-100℃ / s: minimizing the conditions for the generation of dioxins. If the cooling rate is too high, it will increase investment to a certain extent and also bring a large amount of wastewater; if the cooling rate is too low, dioxins will be generated to a certain extent. Specifically, the final cooling temperature can be 80℃ / s, 90℃ / s, 100℃ / s, etc. This step is to rapidly cool the above-mentioned waste gas.

[0059] In the second aspect, based on a general inventive concept, the present application provides a treatment device for hydrogen halide waste gas, see Figure 2 , the device comprises:

[0060] An alkali solution multi-stage spraying device 1 is used for first removing impurities from the hydrogen halide waste gas;

[0061] An incineration device 2, used for incinerating the second hydrogen halide waste gas, and connected to the alkali solution multi-stage spraying device 1;

[0062] A first cooling device 3, used for first cooling the second hydrogen halide waste gas after the incineration, and connected to the incineration device 2;

[0063] A second cooling device 4, used for performing a second cooling on the second hydrogen halide waste gas after incineration, and connected to the first cooling device 3;

[0064] A first ash hopper 5, used for collecting first fly ash, connected to the alkali solution multi-stage spraying device 1;

[0065] The second ash hopper 6 is used for collecting the second fly ash and the third fly ash and is connected to the incineration device 2 .

[0066] Hydrogen halide is a strong acid. High-temperature and high-concentration hydrogen halide waste gas undergoes an acid-base neutralization reaction in the alkali solution multi-stage spray device 1 to generate halide salts. Halides exist in the alkali solution spray tower in the form of fly ash. The waste gas enters and exits the alkali solution multi-stage spray device from top to bottom, and the fly ash is freely settled in the tower, which greatly reduces the fly ash being carried by the waste gas into the subsequent incineration device 2 treatment section. In addition, a calcium oxide powder injection port is set at the inlet of the incineration device, and the halide in the waste gas entering the incineration device 2 reacts with calcium oxide to generate insoluble solid calcium halide, further removing the halide carried in the waste gas.

[0067] The waste gas with high temperature and high concentration of hydrogen halide enters directly from the top of the alkali solution spraying device 1, and undergoes neutralization reaction through multi-stage alkali solution spraying to remove hydrogen halide, sulfide, etc. The generated salt fly ash settles by gravity in the alkali solution multi-stage spraying device 1 and is collected by the ash hopper 5 at the bottom of the tower. The waste gas with high concentration of hydrogen halide removed passes through the front end of the incinerator, and further reacts with the injected calcium oxide powder, activated carbon, etc. to remove a small amount of halide carried in the waste gas. The formed salt fly ash settles by gravity in the incineration device 2 and enters the ash hopper 6. The waste gas with secondary removal of hydrogen halide enters the incinerator for organic matter incineration treatment. After incineration, it passes through the first cooling device 3 and then enters the second cooling device 4 to rapidly cool the waste gas to the target final cooling temperature to prevent the generation of dioxins.

[0068] In some embodiments, the device further comprises: an alkali solution storage and transportation device 7; the alkali solution storage and transportation device comprises:

[0069] The alkali solution storage device 71 is used for storing alkali solution; the alkali solution conveying device 72 is used for conveying alkali solution and is connected to the alkali solution storage device 71 .

[0070] In some embodiments, the device further comprises: a third cooling device 8, which is used to perform a third cooling on the target hydrogen halide waste gas and is connected to the second cooling device;

[0071] A smoke exhaust fan 9, used for conveying the target hydrogen halide waste gas after the third cooling; connected to the third cooling device 8;

[0072] The chimney 10 is used to discharge the target hydrogen halide waste gas after the third cooling and is connected to the smoke exhaust fan 9.

[0073] The fly ash generated in the second cooling device 4 is collected by the ash hopper 6 at the bottom of the tower after gravity settling. Finally, the exhaust gas is cooled to the discharge temperature by the third cooling device 8, and after meeting the environmental protection and safety discharge requirements, it is discharged into the atmosphere through the smoke exhaust fan 9 and the chimney 10. The second cooling device 4 is a quenching tower.

[0074] In some embodiments, the first cooling device 3 and the third cooling device 8 are both heat exchange devices.

[0075] The above-mentioned heat exchange device can recover and recycle the waste heat of high-temperature exhaust gas generated during the exhaust gas treatment process.

[0076] The device for treating hydrogen halide waste gas is realized based on the above-mentioned method for treating hydrogen halide waste gas. The specific steps of the method for treating hydrogen halide waste gas can refer to the above-mentioned embodiment. Since the device for treating hydrogen halide waste gas adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0077] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0078] Example steps:

[0079] S1. Using alkali solution and performing a first impurity removal on the hydrogen halide waste gas by a multi-stage spraying method to obtain a first fly ash and a first hydrogen halide waste gas;

[0080] S2. performing a second impurity removal on the first hydrogen halide waste gas using an alkaline material to obtain second fly ash and a second hydrogen halide waste gas;

[0081] S3, incinerating the second hydrogen halide waste gas, and then cooling it in stages to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature; the first fly ash, the second fly ash and the third fly ash are collected after gravity sedimentation. For specific process parameters, please refer to Table 1.

[0082] Table 1

[0083]

[0084] Comparative Example 1

[0085] The waste gas is directly incinerated at high temperature, and the incinerated waste gas is rapidly cooled, and finally removed by alkali washing in an alkali washing tower to remove hydrogen halide and meet the safety and environmental protection requirements before being discharged. The impurity removal rate is 95%.

[0086] By adopting the method of the embodiment of the present application, the waste gas is rigorously removed in steps, which is beneficial to environmental protection. In comparative example 1, the multi-stage spraying method is not adopted, and the high concentration of hydrogen halide in the waste gas will be highly corrosive to the furnace body, greatly shortening the service life of the incinerator. Due to the presence of hydrogen halide, the high-temperature waste gas after incineration has high material requirements for heat recovery equipment, resulting in an increase in the heat recovery cost of the waste gas. After the waste gas enters the rapid cooling, the hydrogen halide is still highly corrosive to the tower body, shortening the service life of the equipment and increasing the investment cost. In addition, when alkali solution is used to remove hydrogen halide in the alkali washing tower, a large amount of wastewater and waste liquid will be generated, causing serious environmental pollution.

[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for treating hydrogen halide waste gas, characterized in that: The method comprises: Using alkali solution and performing a first impurity removal on the hydrogen halide waste gas by a multi-stage spraying method to obtain a first fly ash and a first hydrogen halide waste gas; Performing a second impurity removal on the first hydrogen halide waste gas by using an alkaline material to obtain second fly ash and second hydrogen halide waste gas; The second hydrogen halide waste gas is incinerated and then cooled in stages to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature; the first fly ash, the second fly ash and the third fly ash are respectively collected after gravity sedimentation.

2. The method according to claim 1, characterized in that: The alkaline material includes at least one of the following: sodium hydroxide and calcium oxide.

3. The method according to claim 1, characterized in that The target final cooling temperature is 200-280°C.

4. The method according to claim 1, characterized in that: The second hydrogen halide waste gas is incinerated and then cooled in stages to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature, comprising: Incinerating the second hydrogen halide waste gas, and then performing a first cooling; Under the condition of a set cooling rate, the second hydrogen halide waste gas after the first cooling is subjected to a second cooling to obtain third fly ash and target hydrogen halide waste gas; wherein the target hydrogen halide waste gas has a target final cooling temperature.

5. The method according to claim 4, characterized in that The initial temperature of the first cooling is 800-1100°C, and the end temperature of the first cooling is 300-500°C.

6. The method according to claim 4 or 5, characterized in that: The set cooling rate is 80-100°C / s.

7. A device for treating hydrogen halide waste gas, characterized in that: The device comprises: An alkali solution multi-stage spraying device (1) is used to perform a first impurity removal on the hydrogen halide waste gas; An incineration device (2), used for incinerating the second hydrogen halide waste gas, and connected to the alkali solution multi-stage spraying device (1); A first cooling device (3), used for performing a first cooling on the second hydrogen halide waste gas after the incineration, and connected to the incineration device (2); A second cooling device (4), used for performing a second cooling on the second hydrogen halide waste gas after incineration, and connected to the first cooling device (3); A first ash hopper (5), used for collecting first fly ash, connected to the alkali solution multi-stage spraying device (1); The second ash hopper (6) is used to collect the second fly ash and the third fly ash and is connected to the incineration device (2).

8. The device according to claim 7, characterized in that The device also includes: Alkali solution storage and transportation device (7); the alkali solution storage and transportation device comprises: An alkali solution storage device (71) for storing alkali solution; The alkali solution conveying device (72) is used for conveying alkali solution and is connected to the alkali solution storage device (71).

9. The device according to claim 7, characterized in that The device also includes: a third cooling device (8), used for performing a third cooling on the target hydrogen halide waste gas, and connected to the second cooling device (4); A smoke exhaust fan (9), used for conveying the target hydrogen halide waste gas after the third cooling; and connected to the third cooling device (8); A chimney (10) is used to discharge the target hydrogen halide waste gas after the third cooling, and the exhaust fan (9) Connectivity.

10. The device according to claim 9, characterized in that The first cooling device (3) and the third cooling device (8) are both heat exchange devices.

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