Low-temperature catalytic treatment device for lime rotary kiln tail gas
By adopting a wave-shaped reaction gas channel and steam box heating method in the lime rotary kiln tail gas treatment device, the problem of high energy consumption for SCR tank heating was solved, low-temperature catalytic treatment was achieved, energy consumption was reduced and heat utilization efficiency was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- QINGHAI YIHUA CHEM
- Filing Date
- 2024-11-04
- Publication Date
- 2026-07-03
AI Technical Summary
In existing lime rotary kiln tail gas treatment, the SCR tank heating energy consumption is high and the heat is difficult to concentrate, resulting in excessive energy consumption for catalytic treatment.
The reactor is equipped with a C-shaped reaction chamber and gas guide pipes to form a wave-shaped reaction gas channel. The reaction chamber is heated to 320-420°C by a steam box, which concentrates the heat to the reaction gas channel and reduces heat loss. The diluted ammonia gas is mixed with the tail gas to carry out the catalytic reaction.
This reduces heating energy consumption during the catalytic treatment of exhaust gas, improves heat utilization efficiency, achieves low-temperature catalytic treatment, and reduces energy consumption.
Smart Images
Figure CN224442643U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of tail gas treatment technology, specifically relating to a low-temperature catalytic treatment device for tail gas from a lime rotary kiln. Background Technology
[0002] Lime rotary kilns emit a large amount of exhaust gas during production, mainly consisting of dust, NOx, SO2, CO2, and CO. This exhaust gas is typically first passed through a scrubbing tower to remove dust, SO2, CO2, and CO. The remaining NOx gas is usually treated using SCR (Special Catalytic Reduction) technology.
[0003] SCR technology involves transporting liquid ammonia by truck to a liquid ammonia storage tank, heating it into ammonia gas via an evaporator, and then allowing it to pass through a pressure-reducing valve into an ammonia buffer tank. A dilution fan mixes the ammonia gas with the gas in a specific ratio using an ammonia mixer. The diluted ammonia gas then enters the flue gas grid through nozzles in the ammonia injection system, mixing with the original flue gas. Under the action of a catalyst, nitrogen oxides in the flue gas react chemically with the ammonia gas, thereby removing nitrogen oxides.
[0004] When using SCR technology to treat the tail gas of existing lime rotary kilns, the tail gas and ammonia are introduced into the SCR tank in a certain ratio and treated by heating with a catalyst. However, the spiral gas passage inside the SCR tank extends the tail gas path and is heated throughout the spiral gas passage. The heating area is wide, and the internal baffles are also heated. This makes it difficult to effectively concentrate the heat on the mixed gas flow, resulting in high heating energy consumption during the catalytic treatment of tail gas in the SCR tank. Therefore, we propose a low-temperature catalytic treatment device for lime rotary kiln tail gas. Utility Model Content
[0005] The purpose of this invention is to provide a low-temperature catalytic treatment device for the tail gas of a lime rotary kiln, which can concentrate the heat of the steam into the wave-shaped reaction gas channel, reduce the heat loss to the tank body partition, and thus reduce the heating energy consumption in the catalytic treatment of the tail gas.
[0006] The specific technical solution adopted in this utility model is as follows:
[0007] A low-temperature catalytic treatment device for tail gas from a lime rotary kiln includes a tank. Inside the tank, several reaction chambers are arranged in a C-shape at intervals. Each reaction chamber is fixedly connected to the tank. A gas guide pipe is fixedly connected between the sides of two adjacent reaction chambers, and the two adjacent gas guide pipes are staggered. One end of each of the two reaction chambers located at the two ends of the C-shape is fixedly connected to a main gas pipe, which is used for gas inlet and outlet, respectively. An ammonia gas pipe is fixedly connected to the outside of each reaction chamber. One end of each gas guide pipe, one end of each main gas pipe, and one end of each ammonia gas pipe extends out of the tank. A steam box is fixed in the middle of the tank. During tail gas treatment, a main gas pipe is introduced into the tank along one side of the reaction chamber. Several reaction chambers and gas guide pipes arranged in a "C" shape form a wave-shaped reaction gas channel to guide the tail gas. At the same time, diluted ammonia is injected along several ammonia pipes, and these reaction chambers are heated to 320-420°C by a steam box. This concentrates the heat of the steam into the wave-shaped reaction gas channel, reducing the heat loss to the tank partition and thus reducing the heating energy consumption during the catalytic treatment of tail gas. This allows the nitrogen oxides and ammonia in the tail gas to be fully heated and catalytically reacted under the action of the catalyst for denitrification treatment. The mixture after the reaction is transported to the scrubbing tower along another main gas pipe.
[0008] The inner wall of the tank is fixed with a ring-shaped insulation layer, which is fixedly connected to the reaction chamber to reduce the heat loss caused by heat exchange between the tank and the air.
[0009] A support plate is fixed between the two adjacent reaction chambers on their sides, and a gap is left between the support plate and the gas guide pipe, which can fix the reaction chambers from both sides, strengthen them, and offset the impact of the exhaust gas.
[0010] The tank body is detachably fixed with cover plates at both ends, which can be secured with bolts. By rotating the bolts clockwise along the threads until all bolts are unscrewed, the cover plates can be removed, making it easy to expose the reaction tank and steam tank for maintenance.
[0011] Both ends of the steam box are connected and fixed with steam pipes. The two steam pipes pass through the two cover plates respectively. One steam pipe is connected to the steam source for inputting steam, and the other steam pipe is connected to the waste gas treatment tower or the waste heat recovery pipe.
[0012] A sampling tube is also fixedly connected to the outside of the reaction chamber. One end of the sampling tube extends out of the tank and can be normally closed with a valve. It can be opened when sampling is needed, and samples can be taken as needed.
[0013] The technical effects achieved by this utility model are as follows:
[0014] This invention relates to a low-temperature catalytic treatment device for tail gas from a lime rotary kiln. During tail gas treatment, a main gas pipe is introduced into the tank. Several reaction chambers and gas guide pipes arranged in a "C" shape form a wave-shaped reaction gas channel to guide the tail gas. At the same time, diluted ammonia gas is injected along several ammonia gas pipes, and these reaction chambers are simultaneously heated to 320-420°C by a steam box. This concentrates the heat of the steam into the wave-shaped reaction gas channel, reducing the heat loss to the tank body partition and thus reducing the heating energy consumption during the catalytic treatment of tail gas. This allows the nitrogen oxides and ammonia in the tail gas to be fully heated and catalytically reacted under the action of the catalyst for denitrification treatment. The resulting mixture is then transported to a gas scrubbing tower along another main gas pipe. Attached Figure Description
[0015] Figure 1 This is a front view of a practical low-temperature catalytic treatment device for tail gas from a lime rotary kiln;
[0016] Figure 2 This is a cross-sectional view of a low-temperature catalytic treatment device for tail gas from a lime rotary kiln.
[0017] Figure 3 This is a front view of several reaction chambers in this practical tool;
[0018] Figure 4 This is a cross-sectional view of the practical steam box.
[0019] The attached diagram lists the components represented by each number as follows:
[0020] 1. Tank body; 2. Reaction chamber; 3. Gas delivery pipe; 4. Main gas pipe; 5. Ammonia gas pipe; 6. Steam box; 7. Insulation layer; 8. Support plate; 9. Cover plate; 10. Steam pipe; 11. Sampling pipe. Detailed Implementation
[0021] To make the purpose and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the following text is merely used to describe one or more specific implementations of this utility model and does not strictly limit the scope of protection specifically claimed by this utility model.
[0022] like Figure 1-4As shown, a low-temperature catalytic treatment device for tail gas from a lime rotary kiln includes a tank 1. Inside the tank 1, several reaction chambers 2 are arranged in a "C" shape. In the reaction chambers 2, NOx is catalytically reduced to N2 by injecting ammonia or urea (NH3 / NO = 1:1, molar ratio). The catalyst inside the reaction chambers 2 can be TiO2-V2O5. The reaction chambers 2 are fixedly connected to the tank 1. A gas guide pipe 3 is fixedly connected between the sides of two adjacent reaction chambers 2 that are close to each other. The two adjacent gas guide pipes 3 are staggered. One end of each of the two reaction chambers 2 located at the two ends of the "C" shape is fixedly connected to a main gas pipe 4. The two main gas pipes 4 are used for gas inlet and gas outlet, respectively. The main gas pipe 4 used for gas inlet is connected to the tail gas outlet pipe of the lime rotary kiln. Ammonia gas pipes 5 are fixedly connected to the outside of each reaction chamber 2. The inlet end of each ammonia gas pipe 5 is connected to the ammonia port of the SCR denitrification system. One end of the gas guide pipe 3 and the main gas pipe 4 are connected to each other. One end of the ammonia pipe 5 extends out of the interior of the tank 1. A steam box 6 is fixed in the middle of the tank 1 and connected to a steam source. The outer side of the steam box 6 is attached to one side of the reaction box 2. The steam source is started in advance to prepare sufficient steam. During tail gas treatment, a main gas pipe 4 is introduced into the tank 1. The tail gas is guided by a wave-shaped reaction gas channel formed by several reaction boxes 2 and gas guide pipes 3 arranged in a "C" shape. At the same time, diluted ammonia is injected along several ammonia pipes 5, and the steam box 6 heats these reaction boxes 2 to 320-420°C. This concentrates the heat of the steam into the wave-shaped reaction gas channel, reduces the heat lost to the tank 1 partition, and reduces the heating energy consumption in the catalytic treatment of tail gas. The nitrogen oxides and ammonia in the tail gas are fully heated and catalytically reacted under the action of the catalyst for denitrification treatment. The mixture after reaction is transported to the scrubbing tower along another main gas pipe 4.
[0023] Referring to commercially available SCR denitrification systems, the SCR denitrification system used in this embodiment mainly consists of ammonia storage, ammonia mixing, ammonia injection, a reaction tower (catalyst) system, a flue, and a control system. Liquid ammonia is transported by truck to a liquid ammonia storage tank, heated to ammonia gas by an evaporator, and then enters an ammonia buffer tank through a pressure reducing valve. A dilution fan mixes the ammonia gas with the gas in a specific ratio using an ammonia mixer, and the diluted ammonia gas is then introduced into ammonia pipe 5.
[0024] In this embodiment, the heating temperature control can be monitored by purchasing a temperature sensor from the market, which can be implemented by those skilled in the art using common knowledge.
[0025] like Figure 2 and Figure 3 As shown, a ring-shaped insulation layer 7 is fixed to the inner wall of the tank 1. The insulation layer 7 can be made of rock wool board or expanded perlite material. The insulation layer 7 is fixedly connected to the reaction chamber 2 to reduce the heat loss of the tank 1 due to heat exchange with the air.
[0026] like Figure 1 and Figure 2As shown, a support plate 8 is fixed between the two adjacent reaction chambers 2 on the side closest to each other. A gap is left between the support plate 8 and the gas guide pipe 3, which can fix the reaction chambers 2 from both sides, strengthen them, and offset the impact of the exhaust gas.
[0027] like Figure 1 and Figure 2 As shown, both ends of the tank 1 are detachably fixed with cover plates 9, which can be fixed with bolts. By rotating the bolts forward along the threads until all bolts are unscrewed, the cover plates 9 can be removed, making it easy to expose the reaction chamber 2 and the steam chamber 6 for maintenance.
[0028] like Figure 2 and Figure 4 As shown, steam pipes 10 are fixedly connected to both ends of the steam box 6. The two steam pipes 10 pass through the two cover plates 9 respectively. One steam pipe 10 is connected to the steam source for inputting steam, and the other steam pipe 10 is connected to the waste gas treatment tower or the waste heat recovery pipe.
[0029] like Figure 1 , Figure 2 and Figure 3 As shown, a sampling tube 11 is also fixedly connected to the outside of the reaction chamber 2. One end of the sampling tube 11 extends out of the inside of the tank 1. It can be normally closed with a valve and opened when sampling is needed, so that samples can be taken as needed.
[0030] The working principle of this utility model is as follows: During tail gas treatment, a main gas pipe 4 is introduced into the tank 1. Several reaction chambers 2 and gas guide pipes 3 arranged in a "C" shape form a wave-shaped reaction gas channel to guide the tail gas. At the same time, diluted ammonia gas is injected along several ammonia gas pipes 5, and these reaction chambers 2 are heated to 320-420°C by a steam box 6. This concentrates the heat of the steam into the wave-shaped reaction gas channel, reduces the heat lost to the tank 1 partition, and reduces the heating energy consumption in the catalytic treatment of tail gas. This allows the nitrogen oxides and ammonia in the tail gas to be fully heated and catalytically reacted under the action of the catalyst for denitrification treatment. The mixture after the reaction is transported to the scrubbing tower along another main gas pipe 4.
[0031] The above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. Structures, devices, and operating methods not specifically described or explained in this utility model, unless otherwise specified or limited, shall be implemented using conventional methods in the art.
Claims
1. A low-temperature catalytic treatment device for lime rotary kiln tail gas, comprising a tank body (1), characterized in that: The tank (1) has several reaction chambers (2) arranged in a "C" shape inside. The reaction chambers (2) are fixedly connected to the tank (1). A gas guide pipe (3) is fixedly connected between the sides of two adjacent reaction chambers (2) that are close to each other. The two adjacent gas guide pipes (3) are staggered. One end of the two reaction chambers (2) located at both ends of the "C" shape is fixedly connected to a main gas pipe (4). The two main gas pipes (4) are used for gas inlet and gas outlet, respectively. An ammonia pipe (5) is fixedly connected to the outside of the reaction chambers (2). One end of the gas guide pipe (3), one end of the main gas pipe (4) and one end of the ammonia pipe (5) extend out of the tank (1). A steam box (6) is fixed in the middle of the tank (1). The outside of the steam box (6) is attached to one side of the reaction chamber (2).
2. A device for low temperature catalytic treatment of exhaust gases from lime rotary kiln according to claim 1, characterized in that: The inner wall of the tank (1) is fixed with a ring-shaped heat insulation layer (7), and the heat insulation layer (7) is fixedly connected to the reaction chamber (2).
3. A device for low temperature catalytic treatment of exhaust gases from lime rotary kiln according to claim 1, characterized in that: A support plate (8) is fixed between the two adjacent reaction chambers (2) on the side that is close to each other, and a gap is left between the support plate (8) and the gas guide pipe (3).
4. A device for low temperature catalytic treatment of exhaust gases from lime rotary kiln according to claim 1, characterized in that: The tank (1) has detachable cover plates (9) fixed at both ends.
5. A device for low temperature catalytic treatment of exhaust gases from lime rotary kiln according to claim 1, characterized in that: The steam box (6) is connected to two steam pipes (10) at both ends, and the two steam pipes (10) pass through the two cover plates (9) respectively.
6. The low-temperature catalytic treatment device for lime rotary kiln tail gas according to claim 1, characterized in that: A sampling tube (11) is also fixedly connected to the outside of the reaction chamber (2), and one end of the sampling tube (11) extends out of the inside of the tank (1).