Denitration treatment method for tank furnace

Abstract

The invention belongs to the field of environmental protection, and particularly relates to a tank furnace denitration treatment method. The method comprises the following steps that tank furnace combustion flue gas enters a heat exchanger at the tail end of a furnace; while the combustion flue gas of the tank furnace enters the heat exchanger, spraying an organic amine solution into the heat exchanger through a denitration agent spray gun to carry out SNCR denitration treatment on the flue gas; during denitration treatment, the temperature of the flue at the denitration agent spray gun of the first-stage heat exchange section is controlled to be 900-1100 DEG C; the flow of the denitration agent spray gun of the first-stage heat exchange section is controlled to be greater than that of the second-stage heat exchange section; controlling the concentration of the organic amine solution to be less than or equal to 10wt% and the temperature to be more than The method provided by the invention has good SNCR (Selective Non Catalytic Reduction) denitration efficiency and relatively low denitration cost.

Description

Technical Field

[0001] The invention belongs to the field of environmental protection, and in particular relates to a tank kiln denitrification treatment method. Background Art

[0002] At present, the key area of ​​research in atmospheric environmental protection technology is denitrification. Based on factors such as denitrification efficiency, technical reliability, and maintenance costs, the methods widely used in industrial applications include selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR).

[0003] At present, the denitrification treatment of the flue gas of the pool kiln is generally carried out in the heat exchanger at the tail end of the kiln, using the SNCR method for denitrification. Specifically, the heat exchanger at the tail end of the kiln is provided with several injection points of the denitrifier, and the injected denitrifier is mixed with the flue gas and contacts with the nitrogen oxides (NO X ) to react to generate N2 and H2O, thereby achieving the removal of nitrogen oxides in the flue gas. At present, the temperature of the flue gas entering the heat exchanger of the pool kiln is generally higher than 1200℃, resulting in low denitrification efficiency and high denitrification costs.

[0004] With the continuous improvement of requirements for atmospheric environmental protection, how to maintain a high efficiency SNCR denitrification rate in the process of furnace flue gas treatment while reducing the cost investment in the denitrification link as much as possible has become a research hotspot in this field. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a tank kiln denitrification treatment method, which has good SNCR denitrification efficiency and low denitrification cost.

[0006] The present invention provides a tank kiln denitrification treatment method, comprising the following process:

[0007] The combustion flue gas of the pool kiln enters the heat exchanger at the tail end of the kiln; the heat exchanger is designed longitudinally, and includes a primary heat exchange section, a secondary heat exchange section, a tertiary heat exchange section, a damping wind section and a chimney section in sequence along the direction of flue gas movement; the primary heat exchange section is provided with two denitrification spray guns, the two denitrification spray guns are of the same height and are symmetrically arranged in the horizontal direction; the secondary heat exchange section is provided with two denitrification spray guns, the two denitrification spray guns are of the same height and are symmetrically arranged in the horizontal direction; the spatial angle between the two denitrification spray guns provided in the primary heat exchange section and the two denitrification spray guns provided in the secondary heat exchange section along the horizontal direction is 90°; the feed ends of the two denitrification spray guns provided in the primary heat exchange section and the two denitrification spray guns provided in the secondary heat exchange section are both connected to the air compressor;

[0008] When the furnace combustion flue gas enters the heat exchanger, the organic amine solution is sprayed into the heat exchanger through the denitrification agent spray gun to perform SNCR denitrification treatment on the flue gas; during the denitrification treatment, the flue temperature at the denitrification agent spray gun of the first-level heat exchange section is controlled to be 900-1100°C; the flow rate of the denitrification agent spray gun of the first-level heat exchange section is controlled to be greater than that of the second-level heat exchange section; the concentration of the organic amine solution is controlled to be ≤10wt%, and the temperature is controlled to be ≥20°C.

[0009] Preferably, the flue temperature at the denitrification agent spray gun in the first-stage heat exchange section is controlled to be 1000°C.

[0010] Preferably, during the denitration treatment, the flue temperature at the denitration agent spray gun of the secondary heat exchange section is controlled to be 1100-1250°C.

[0011] Preferably, during the denitration treatment, the flue temperature at the denitration agent spray gun of the secondary heat exchange section is controlled to be 1200°C.

[0012] Preferably, during the denitration treatment, the denitration agent spray gun flow rate of the primary heat exchange section is 30-40 L / h.

[0013] Preferably, during the denitration treatment, the air pressure of the denitration agent spray gun in the primary heat exchange section is 0.1-0.2 MPa.

[0014] Preferably, during the denitration treatment, the denitration agent spray gun flow rate of the secondary heat exchange section is 20-30 L / h.

[0015] Preferably, during the denitration treatment, the air pressure of the denitration agent spray gun of the secondary heat exchange section is 0.1-0.2 MPa.

[0016] Preferably, during the denitration treatment, the concentration of the organic amine solution is controlled to be 5-10 wt %.

[0017] Preferably, during the denitration treatment, the temperature of the organic amine solution is controlled at 20-40°C.

[0018] Compared with the prior art, the present invention provides a pool kiln denitrification treatment method, which includes the following processes: the combustion flue gas of the pool kiln enters the heat exchanger at the tail end of the kiln; the heat exchanger is designed longitudinally, and includes a primary heat exchange section, a secondary heat exchange section, a tertiary heat exchange section, a damping wind section and a chimney section in sequence along the direction of flue gas movement; the primary heat exchange section is provided with two denitrification agent spray guns, the two denitrification agent spray guns are of the same height and are symmetrically arranged in the horizontal direction; the secondary heat exchange section is provided with two denitrification agent spray guns, the two denitrification agent spray guns are of the same height and are symmetrically arranged in the horizontal direction; the two denitrification agent spray guns arranged in the primary heat exchange section are aligned with the two denitrification agent spray guns arranged in the secondary heat exchange section. The spatial angle of the two denitrification agent spray guns in the horizontal direction is 90°; the feed ends of the two denitrification agent spray guns arranged in the first heat exchange section and the two denitrification agent spray guns arranged in the second heat exchange section are both connected to the air compressor; while the flue gas from the pool kiln combustion enters the heat exchanger, the organic amine solution is sprayed into the heat exchanger through the denitrification agent spray gun to perform SNCR denitrification on the flue gas; during the denitrification treatment, the flue temperature at the denitrification agent spray gun in the first heat exchange section is controlled to be 900~1100℃; the flow rate of the denitrification agent spray gun in the first heat exchange section is controlled to be greater than that in the second heat exchange section; the concentration of the organic amine solution is controlled to be ≤10wt%, and the temperature is controlled to be ≥20℃. The present invention realizes the efficient utilization of the denitrification agent by optimizing and controlling the reaction environment of SNCR denitrification, as well as the concentration, temperature and spraying method of the denitrification agent solution, which not only improves the denitrification efficiency, but also reduces the amount of the denitrification agent, and has good environmental and economic benefits. The experimental results show that the technical solution of the present invention achieves higher denitrification efficiency under the conditions of lower denitrification agent concentration and lower denitrification agent dosage, and the economic and environmental benefits are very outstanding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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 embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the segmented structure of the heat exchanger and the distribution position of the spray guns provided in an embodiment of the present invention.

[0021] Explanation of the figure numbers: 1 is the primary heat exchange section, 2 is the secondary heat exchange section, 3 is the tertiary heat exchange section, 4 is the damping wind section, 5 is the chimney section, 6 is the denitrification agent spray gun setting position of the primary heat exchange section, and 7 is the denitrification agent spray gun setting position of the secondary heat exchange section. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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.

[0023] The present invention provides a tank kiln denitrification treatment method, comprising the following process:

[0024] The combustion flue gas of the pool kiln enters the heat exchanger at the tail end of the kiln; the heat exchanger is designed longitudinally, and includes a primary heat exchange section, a secondary heat exchange section, a tertiary heat exchange section, a damping wind section and a chimney section in sequence along the direction of flue gas movement; the primary heat exchange section is provided with two denitrification spray guns, the two denitrification spray guns are of the same height and are symmetrically arranged in the horizontal direction; the secondary heat exchange section is provided with two denitrification spray guns, the two denitrification spray guns are of the same height and are symmetrically arranged in the horizontal direction; the spatial angle between the two denitrification spray guns provided in the primary heat exchange section and the two denitrification spray guns provided in the secondary heat exchange section along the horizontal direction is 90°; the feed ends of the two denitrification spray guns provided in the primary heat exchange section and the two denitrification spray guns provided in the secondary heat exchange section are both connected to the air compressor;

[0025] When the furnace combustion flue gas enters the heat exchanger, the organic amine solution is sprayed into the heat exchanger through a denitrification agent spray gun to perform SNCR denitrification treatment on the flue gas.

[0026] In the method provided by the present invention, the temperature of the flue gas can be reduced by increasing the proportion of electric melting power input of the kiln and increasing the air volume of the waste heat fan, so that the temperature of the flue gas when it flows through the denitrification agent spray gun of the first-level heat exchange section meets the requirements. In the present invention, the flue temperature at the denitrification agent spray gun of the first-level heat exchange section is controlled at 900~1100℃, specifically 900℃, 950℃, 1000℃, 1050℃ or 1100℃; the flue temperature at the denitrification agent spray gun of the second-level heat exchange section is controlled at 1100~1250℃, specifically 1000℃, 1050℃, 1100℃, 1150℃, 1200℃ or 1250℃.

[0027] In the method provided by the present invention, the two denitrification agent spray guns of the first heat exchange section are preferably arranged on the east and west sides of the heat exchanger as the main denitrification force; the two denitrification agent spray guns of the second heat exchange section are preferably arranged on the north and south sides of the heat exchanger as the auxiliary denitrification force. In actual use, the flow rate of the denitrification agent spray gun of the first heat exchange section is controlled to be greater than that of the second heat exchange section, which can effectively reduce the overall consumption of the denitrification agent (organic amine). In the present invention, the denitrification agent spray gun flow rate of the primary heat exchange section is preferably 30-40 L / h, specifically 30 L / h, 31 L / h, 32 L / h, 33 L / h, 34 L / h, 35 L / h, 36 L / h, 37 L / h, 38 L / h, 39 L / h or 40 L / h; the denitrification agent spray gun flow rate of the secondary heat exchange section is preferably 20-30 L / h, specifically 20 L / h, 21 L / h, 22 L / h, 23 L / h, 24 L / h, 25 L / h, 26 L / h, 27 L / h, 28 L / h, 29 L / h or 30 L / h.

[0028] In the method provided by the present invention, the compressed air pressure of the denitrification agent spray gun needs to be stabilized during the denitrification process. If the air pressure is too low, the denitrification agent spray mist cross-sectional area will be insufficient, and the optimal effect will not be achieved; if the air pressure is too high, the spray volume will be too large, resulting in a waste of denitrification agent. Therefore, the present invention sets a separate air compressor to provide compressed air for the denitrification agent spray gun to avoid fluctuations in the compressed air in the production pipeline network, which affects the denitrification agent spraying effect. In the present invention, the air pressure of the denitrification agent spray gun in the primary heat exchange section is preferably 0.1-0.2 MPa, specifically 0.1 MPa, 0.11 MPa, 0.12 MPa, 0.13 MPa, 0.14 MPa, 0.15 MPa, 0.16 MPa, 0.17 MPa, 0.18 MPa, 0.19 MPa or 0.2 MPa; the air pressure of the denitrification agent spray gun in the secondary heat exchange section is preferably 0.1-0.2 MPa, specifically 0.1 MPa, 0.11 MPa, 0.12 MPa, 0.13 MPa, 0.14 MPa, 0.15 MPa, 0.16 MPa, 0.17 MPa, 0.18 MPa, 0.19 MPa or 0.2 MPa.

[0029] In the method provided by the present invention, the organic amine solution for denitration is preferably prepared by stirring with warm water during the preparation process to increase the overall temperature of the organic amine solution and reduce the tendency of the organic amine to crystallize; in the present invention, the temperature of the organic amine solution is preferably ≥20°C, more preferably 20-40°C, specifically 20°C, 25°C, 30°C, 35°C or 40°C. In addition, the concentration of the organic amine solution is reasonably adjusted, and the concentration of the organic amine solution should not be higher than 10wt%, preferably 5-10wt%, specifically 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, to prevent the organic amine crystallization from causing blockage of the pipeline and the spray gun.

[0030] The technical solution provided by the present invention achieves efficient utilization of the denitrifier by optimizing and controlling the reaction environment of SNCR denitrification, as well as the concentration, temperature and spraying method of the denitrifier solution, thereby improving the denitrification efficiency and reducing the amount of the denitrifier, and has good environmental and economic benefits.

[0031] For the purpose of greater clarity, the present invention is described in detail with reference to the following examples and comparative examples.

[0032] Example 1

[0033] A tank kiln denitrification treatment method includes the following processes:

[0034] The combustion flue gas of the pool kiln enters the heat exchanger at the tail end of the kiln; at the same time, the organic amine solution is sprayed into the heat exchanger through the denitrification agent spray gun to perform SNCR denitrification treatment on the flue gas;

[0035] The structure of the heat exchanger is as follows Figure 1 As shown, the heat exchanger is designed longitudinally, and includes a primary heat exchange section 1 (weight 6 tons), a secondary heat exchange section 2 (weight 7 tons), a tertiary heat exchange section 3 (weight 6.5 tons), a damping wind section 4 (weight 2.5 tons) and a chimney section 5 (weight 0.7 tons) in the direction of flue gas movement; the primary heat exchange section 1 is provided with two denitrification agent spray guns, and the heights of the two denitrification agent spray guns are the same, and the specific setting height is Figure 1 At the position marked 6, two denitrification agent spray guns are symmetrically arranged on the east and west sides of the heat exchanger in the horizontal direction; two denitrification agent spray guns are arranged in the secondary heat exchange section 2, and the heights of the two denitrification agent spray guns are the same, and the specific setting height is Figure 1 At the position marked 7, two denitrification agent spray guns are symmetrically arranged on the north and south sides of the heat exchanger in the horizontal direction, that is, the spatial angle between the two denitrification agent spray guns arranged in the first-stage heat exchange section 1 and the two denitrification agent spray guns arranged in the second-stage heat exchange section 2 is 90°; the feed ends of the two denitrification agent spray guns arranged in the first-stage heat exchange section 1 and the two denitrification agent spray guns arranged in the second-stage heat exchange section 2 are both connected to the air compressor;

[0036] During the denitration process, the flue temperature at the denitrification agent spray gun of the primary heat exchange section 1 is controlled to be 1000°C, and the flue temperature at the denitrification agent spray gun of the secondary heat exchange section 2 is controlled to be 1200°C;

[0037] During the denitration treatment, the organic amine in the organic amine solution used is specifically urea, the solution concentration is 9wt%, and the temperature of the solution is controlled at 30°C during the preparation and transportation process;

[0038] During the denitration treatment, the denitration agent spray gun air pressure of the first-stage heat exchange section 1 is controlled at 0.15MPa, and the spray gun flow rate is controlled at 35L / h; the denitration agent spray gun air pressure of the second-stage heat exchange section 2 is controlled at 0.15MPa, and the spray gun flow rate is controlled at 25L / h;

[0039] During the denitrification process, the flue gas intake of the heat exchanger is 7300m³ / h, and the intake NO X The content is 1898m³ / h, and the NO X The content is 43m³ / h and the denitrification efficiency is 97.7%.

[0040] Comparative Example 1

[0041] A tank kiln denitrification treatment method includes the following processes:

[0042] The combustion flue gas of the pool kiln enters the heat exchanger at the rear end of the kiln (the structure of the heat exchanger is consistent with that of Example 1); at the same time, the organic amine solution is sprayed into the heat exchanger through a denitrification agent spray gun to perform SNCR denitrification treatment on the flue gas;

[0043] During the denitration treatment, the flue temperature at the denitrification agent spray gun of the primary heat exchange section 1 is 1200°C, and the flue temperature at the denitrification agent spray gun of the secondary heat exchange section 2 is 1250°C;

[0044] During the denitration treatment, the organic amine in the organic amine solution used is specifically urea, the solution concentration is 17%, and the temperature of the solution is controlled at 30°C during the preparation and transportation process;

[0045] During the denitration treatment, the denitration agent spray gun gas pressure of the first-stage heat exchange section 1 is 0.15MPa, and the spray gun flow rate is 120L / h; the denitration agent spray gun gas pressure of the second-stage heat exchange section 2 is 0.15MPa, and the spray gun flow rate is 30L / h;

[0046] During the denitration process, the flue gas intake of the heat exchanger is 7300m³ / h, and the intake NO X The content is 1898m³ / h, and the NO X The content is 70m³ / h and the denitrification efficiency is 96.3%.

[0047] By comparing Example 1 with Comparative Example 1, it is not difficult to see that the technical solution provided in Example 1 achieves higher denitrification efficiency under the conditions of lower denitrification agent concentration and lower denitrification agent dosage, and the economic and environmental benefits are very outstanding.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A tank kiln denitrification treatment method, characterized in that: The process includes: The combustion flue gas of the pool kiln enters the heat exchanger at the tail end of the kiln; the heat exchanger is designed longitudinally, and includes a primary heat exchange section, a secondary heat exchange section, a tertiary heat exchange section, a damping wind section and a chimney section in sequence along the direction of flue gas movement; the primary heat exchange section is provided with two denitrification spray guns, the two denitrification spray guns are of the same height and are symmetrically arranged in the horizontal direction; the secondary heat exchange section is provided with two denitrification spray guns, the two denitrification spray guns are of the same height and are symmetrically arranged in the horizontal direction; the spatial angle between the two denitrification spray guns provided in the primary heat exchange section and the two denitrification spray guns provided in the secondary heat exchange section along the horizontal direction is 90°; the feed ends of the two denitrification spray guns provided in the primary heat exchange section and the two denitrification spray guns provided in the secondary heat exchange section are both connected to the air compressor; When the furnace combustion flue gas enters the heat exchanger, the organic amine solution is sprayed into the heat exchanger through the denitrification agent spray gun to perform SNCR denitrification treatment on the flue gas; during the denitrification treatment, the flue temperature at the denitrification agent spray gun of the first-level heat exchange section is controlled to be 900-1100°C; the flow rate of the denitrification agent spray gun of the first-level heat exchange section is controlled to be greater than that of the second-level heat exchange section; the concentration of the organic amine solution is controlled to be ≤10wt%, and the temperature is controlled to be ≥20°C.

2. The tank kiln denitrification treatment method according to claim 1, characterized in that: The flue temperature at the denitrification agent spray gun of the first-stage heat exchange section is controlled to be 1000°C.

3. The tank kiln denitrification treatment method according to claim 1, characterized in that: During the denitration process, the flue temperature at the denitration agent spray gun of the secondary heat exchange section is controlled to be 1100-1250°C.

4. The tank kiln denitrification treatment method according to claim 3, characterized in that: During the denitration process, the flue temperature at the denitration agent spray gun of the secondary heat exchange section is controlled to be 1200°C.

5. The tank kiln denitrification treatment method according to claim 1, characterized in that: During the denitration treatment, the flow rate of the denitration agent spray gun in the first-stage heat exchange section is 30-40 L / h.

6. The tank kiln denitrification treatment method according to claim 1, characterized in that: During the denitration treatment, the denitration agent spray gun gas pressure of the first-stage heat exchange section is 0.1-0.2 MPa.

7. The tank kiln denitrification treatment method according to claim 1, characterized in that: During the denitration treatment, the denitration agent spray gun flow rate of the secondary heat exchange section is 20~30L / h.

8. The tank kiln denitrification treatment method according to claim 1, characterized in that: During the denitration treatment, the denitration agent spray gun gas pressure of the secondary heat exchange section is 0.1~0.2MPa.

9. The tank kiln denitrification treatment method according to claim 1, characterized in that: During the denitration treatment, the concentration of the organic amine solution is controlled to be 5-10wt%.

10. The tank kiln denitrification treatment method according to claim 1, characterized in that: During the denitration treatment, the temperature of the organic amine solution is controlled at 20-40°C.

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