Method and device for reducing sulfur poisoning failure rate of diesel engine aftertreatment system

Abstract

The invention relates to the technical field of engines, in particular to a method and device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system.The device comprises an adsorption desulfurization device, an oxidation catalytic converter, a particle trap and a selective catalytic reduction device which are sequentially connected in series through ventilation pipelines; a first SO2 sensor and a first temperature sensor are arranged on the front side of a gas inlet of the adsorption desulfurization device, a second SO2 sensor and a second temperature sensor are arranged on the rear side of a gas outlet of the adsorption desulfurization device, and a urea injection system is arranged on the front side of a gas inlet of the selective catalytic reduction device. According to the method and device for reducing the sulfur poisoning failure rate of the diesel engine aftertreatment system, circulating desulfurization and sulfur resource recovery are achieved on the premise that the denitration efficiency is guaranteed, the sulfur poisoning failure rate is reduced, and the service life of an SCR system is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a method and a device for reducing the sulfur poisoning failure rate of a diesel engine post-treatment system. Background Art

[0002] Diesel exhaust pollutants include PM, NOx and a small amount of SO 2 At a certain exhaust temperature, the ammonia produced by the thermal decomposition of urea will react with SO 2 It forms a very sticky sulfide with water. On the one hand, it will adhere to a large number of soot particles, and on the other hand, it will be deposited in the gaps of the catalyst attachment. Under the catalytic action, it aggregates into colloid carbon deposits that are not easy to decompose. This phenomenon can cause the SCR catalyst to be poisoned and fail, the conversion rate to drop, and the diesel vehicle to have increased fuel consumption, insufficient power, and excessive nitrogen oxide emissions; in severe cases, it can cause the catalyst to be blocked, the OBD alarm to limit torque and speed, and the diesel vehicle cannot drive normally. In addition, ammonia and SO 2 The sulfides formed by reaction with water have a strong corrosive effect on the copper-based carrier of the SCR catalyst of National VI diesel vehicles. If not removed in time, the service life of the catalyst will be greatly shortened.

[0003] In addition, some customers are keen on pursuing cheap fuel products in order to save transportation costs. Cheap fuel products are usually filled with non-compliant fuel with high sulfur content, and the exhaust gas after combustion contains SO 2 , SO 2 It reacts with the metal-containing catalyst repair substrate coating or water to form sulfate or sulfuric acid, which is finally adsorbed on the surface of the catalyst, causing sulfur poisoning of the copper-based SCR, which in turn leads to a decrease in the SCR conversion efficiency.

[0004] In the existing technology, most diesel engines use post-treatment systems such as DOC, DPF, and SCR to control emissions. However, the existing post-treatment systems have strict requirements on fuel quality. What the post-treatment system manufacturers need is not only to reduce the sulfur poisoning failure rate to extend the service life of the SCR system, but also to adapt to low-grade fuel technology to a certain extent. SCR technology can remove nitrogen oxides from diesel vehicle exhaust, but the core catalyst of the SCR device is very susceptible to sulfur poisoning, especially in vehicles filled with low-quality fuel. When customers use low-grade fuel, the probability of sulfur poisoning in the SCR system increases significantly, resulting in frequent desulfurization and increased fuel consumption, which affects the user experience.

[0005] In view of the above shortcomings, in order to reduce the sulfur poisoning failure rate of the diesel engine after-treatment system and improve the desulfurization and denitrification efficiency of the after-treatment system, an effective method and device are urgently needed to solve the problem of sulfur poisoning or decreased conversion rate of the copper-based SCR catalyst. Summary of the invention

[0006] The purpose of the present invention is to provide a method and device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, realize cyclic desulfurization and sulfur resource recovery under the premise of ensuring denitration efficiency, reduce the sulfur poisoning failure rate and extend the service life of the SCR system.

[0007] To achieve the above object, the present invention provides a device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, comprising an adsorption desulfurization device, an oxidation catalytic converter, a particulate trap and a selective catalytic reduction device connected in series in sequence through a ventilation pipeline, and a SO 2 Sensor 1 and temperature sensor 1, there is a SO 2 Sensor 2 and temperature sensor 2, a urea injection system is provided on the front side of the air intake of the selective catalytic reduction device.

[0008] Preferably, the adsorption desulfurization device includes an adsorption desulfurization tank and a SO 2 Gas collection tank, adsorption desulfurization tank is equipped with an annular insulating partition, the insulating partition separates the inner cavity of the adsorption desulfurization tank into an adsorption chamber and a heating chamber, SO 2 The gas collecting tank is communicated with the heating chamber, a conveyor belt is wound around the insulating partition, and active coke is embedded on the conveyor belt.

[0009] Preferably, a turning port for only the conveyor belt to pass through is provided between the heating chamber and the adsorption chamber, and a fan assembly is also provided in the middle of the adsorption chamber.

[0010] Preferably, a circulation heater is provided in the heating chamber, and the temperature in the heating chamber is set to 600-800°C.

[0011] Preferably, SO 2 The alarm concentration of sensor one is 2000ppm.

[0012] Preferably, the temperature difference between the temperature sensor 1 and the temperature sensor 2 is within 0°C-5°C.

[0013] A method for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, using the above device to reduce the sulfur poisoning failure rate of the diesel engine aftertreatment system.

[0014] Preferably, the method comprises the following steps:

[0015] S1, pass the exhaust gas of the diesel engine into the ventilation pipeline, through SO 2 Sensor 1 monitors SO in exhaust gas 2 concentration;

[0016] S2, if SO 2When the concentration is lower than the alarm concentration, the adsorption desulfurization device will not be started, and the exhaust gas will directly pass through the adsorption desulfurization device, and then be processed through the oxidation catalytic converter, particulate filter and selective catalytic reduction device in sequence;

[0017] S3, if SO 2 When the concentration is higher than the alarm concentration, the adsorption desulfurization device is started, and the tail gas absorbs and desulfurizes in the adsorption desulfurization device to remove SO 2 , and then processed through an oxidation catalytic converter, a particulate filter and a selective catalytic reduction device.

[0018] Beneficial effects of the present invention:

[0019] (1) The present invention provides a device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, by arranging an adsorption desulfurization device on the intake pipe of the aftertreatment system to remove SO in the tail gas through the adsorption desulfurization device. 2 , avoid SO 2 Entering the selective catalytic reduction device, causing sulfur poisoning of the copper-based SCR, affecting the SCR conversion efficiency;

[0020] (2) The present invention provides a method for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, which removes SO in the exhaust gas with high selectivity and efficiency through an adsorption desulfurization device. 2 , and collect SO 2 Then, the diesel engine exhaust CO, hydrocarbons (HC), particulate matter (PM) and NO are controlled through oxidation catalytic converter, particulate filter and selective catalytic reduction device. X Emissions can not only achieve cyclic desorption and sulfur resource recovery, but also effectively reduce the sulfur poisoning failure rate of diesel engine after-treatment system.

[0021] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system of the present invention;

[0023] Figure 2 is a schematic diagram of an adsorption desulfurization device of the present invention;

[0024] Figure 3 is a cross-sectional view of the adsorption desulfurization device of the present invention;

[0025] Figure 4 The present invention Figure 3 A partial enlarged view of point A in the middle.

[0026] Reference numerals:

[0027] 1. Ventilation pipeline;

[0028] 2. Adsorption desulfurization device; 21. Adsorption desulfurization tank; 22. SO 2 Gas collection tank; 23, insulating partition; 24, adsorption chamber; 25, heating chamber; 26, conveyor belt; 27, activated coke; 28, turning port; 29, fan assembly;

[0029] 3. Oxidation catalytic converter; 4. Particle filter; 5. Selective catalytic reduction device; 6. SO 2 Sensor 1; 7, SO 2 Sensor 2; 8. Temperature sensor 1; 9. Temperature sensor 2; 10. Urea injection system. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0031] Example 1

[0032] See also Figures 1 to 4 As shown in the figure, the present invention provides a device for reducing the sulfur poisoning failure rate of a diesel engine post-treatment system, comprising an adsorption desulfurization device 2, an oxidation catalytic converter 3, a particulate trap 4 and a selective catalytic reduction device 5 connected in series in sequence through a ventilation pipeline 1. The adsorption desulfurization device 2 is used to remove SO 2 The oxidation catalytic converter 3 is used to oxidize CO, NO, and hydrocarbons (HC) in the exhaust gas into CO 2 and NO 2 The particulate filter 4 is used to remove particulate matter in the exhaust gas. A urea injection system 10 is provided at the front side of the air inlet of the selective catalytic reduction device 5. The urea injection system 10 is used to inject urea into the selective catalytic reduction device 5 to react with nitrogen oxides entering the selective catalytic reduction device 5 to achieve denitration of the exhaust gas.

[0033] The adsorption desulfurization device 2 includes an adsorption desulfurization tank 21 and a SO 2 Gas collection tank 22, SO 2 The gas collection tank 22 is used to collect the SO desorbed by the adsorption desulfurization tank 21. 2 , realizing the recycling of sulfur resources. An annular insulating partition 23 is provided in the adsorption desulfurization tank 21, and the insulating partition 23 divides the inner cavity of the adsorption desulfurization tank 21 into an adsorption cavity 24 and a heating cavity 25. SO 2The gas collection tank 22 is connected to the heating chamber 25. A conveyor belt 26 is wound around the insulating partition 23. Active coke 27 is embedded in the conveyor belt 26. The active coke is a granular active coke with good adsorption performance in the temperature range of 200-400°C and good desorption performance in the temperature range of 600-800°C in the prior art. A circulating heater in the prior art is provided in the heating chamber 25, and the temperature in the heating chamber 25 is set to 600-800°C. The conveyor belt 26 is driven by the prior art, and the running speed of the conveyor belt 26 is set according to the outer diameter of the adsorption desulfurization device 2 and the adsorption efficiency of the active coke 27.

[0034] The diesel engine exhaust gas enters the adsorption chamber 24 of the adsorption desulfurization tank 21, and the SO 2 The gas is adsorbed onto the activated coke 27, and then the activated coke 27 moves along the conveyor belt 26 into the heating chamber 25, where it is desorbed under high temperature. 2 Enter SO 2 The gas is collected in the gas collection tank 22, SO 2 A check valve in the prior art is provided at the gas inlet of the gas collection tank 22 to prevent SO 2 The gas refluxes, and the desulfurized activated coke 27 moves again along the conveyor belt 26 into the adsorption chamber 24 for cyclic adsorption.

[0035] A turning port 28 is provided between the heating chamber 25 and the adsorption chamber 24, through which only the conveyor belt 26 can pass. The turning port 28 has good sealing performance and prohibits gas from passing through, thereby avoiding the desorption of SO 2 The gas then flows back to the adsorption chamber 24. A fan assembly 29 is also provided in the middle of the adsorption chamber 24. The fan assembly 29 is used to enhance gas disturbance and increase SO 2 adsorption efficiency.

[0036] The front side of the air inlet of the adsorption desulfurization device 2 is provided with SO 2 Sensor 6 and temperature sensor 8, the outlet of the adsorption desulfurization device 2 is provided with a SO 2 Sensor 27 and temperature sensor 29, SO 2 The alarm concentration of sensor 6 is 2000ppm. SO 2 Sensor 6 is used to monitor the SO at the air inlet of the adsorption desulfurization device 2. 2 Concentration, SO 2 Sensor 27 is used to monitor the SO at the outlet of adsorption desulfurization device 2. 2 concentration, by adding SO 2 Sensor-6 and SO 2 Sensor 27 monitors SO 2The concentration is compared so as to timely repair or replace the faulty adsorption desulfurization device 2. The temperature sensor 1 8 is used to monitor the temperature of the air inlet of the adsorption desulfurization device 2, and the temperature sensor 2 9 is used to monitor the temperature of the air outlet of the adsorption desulfurization device 2. The temperature difference between the temperature sensor 1 8 and the temperature sensor 2 9 is within 0°C-5°C.

[0037] Example 2

[0038] A method for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, using the device of Example 1 to reduce the sulfur poisoning failure rate of a diesel engine aftertreatment system, specifically comprising the following steps:

[0039] S1, the exhaust gas of the diesel engine is introduced into the ventilation pipeline 1, through SO 2 Sensor 6 monitors SO in exhaust gas 2 concentration.

[0040] S2, if SO 2 When the concentration is lower than the alarm concentration, the adsorption desulfurization device 2 is not started, and the exhaust gas directly passes through the adsorption desulfurization device 2, and then passes through the oxidation catalytic converter 3, the particulate filter 4 and the selective catalytic reduction device 5 in sequence for treatment before being discharged.

[0041] S3, if there is SO in the tail gas 2 When the concentration rises above the alarm concentration of 2000ppm, SO 2 Sensor 6 alarms, starts the adsorption desulfurization device 2, turns on the conveyor belt 26 and the circulation heater, and makes the temperature in the heating chamber 25 reach 600-800℃. After the tail gas enters the adsorption chamber 24 of the adsorption desulfurization tank 21, the SO 2 The gas is adsorbed onto the activated coke 27 to remove SO in the tail gas. 2 Then the activated coke 27 follows the conveyor belt 26 to move into the heating chamber 25, where it is desorbed under high temperature. 2 Enter SO 2 The gas is collected in the gas collection tank 22, and the desulfurized activated coke 27 is moved again to the adsorption chamber 24 by the conveyor belt 26 for cyclic adsorption to remove SO 2 The exhaust gas is then processed in sequence by the oxidation catalytic converter 3, the particulate trap 4 and the selective catalytic reduction device 5 before being discharged.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, Features: It includes an adsorption desulfurization device, an oxidation catalytic converter, a particulate collector and a selective catalytic reduction device which are connected in series through a ventilation pipeline. The front side of the air inlet of the adsorption desulfurization device is provided with a SO 2 Sensor 1 and temperature sensor 1, there is a SO 2 Sensor 2 and temperature sensor 2, a urea injection system is provided on the front side of the air intake of the selective catalytic reduction device.

2. A device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system according to claim 1, Features: The adsorption desulfurization device includes an adsorption desulfurization tank and a SO 2 Gas collection tank, adsorption desulfurization tank is equipped with an annular insulating partition, the insulating partition separates the inner cavity of the adsorption desulfurization tank into an adsorption chamber and a heating chamber, SO 2 The gas collecting tank is communicated with the heating chamber, a conveyor belt is wound around the insulating partition, and active coke is embedded on the conveyor belt.

3. A device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system according to claim 2, Features: A turning port for only the conveyor belt to pass through is arranged between the heating chamber and the adsorption chamber, and a fan assembly is also arranged in the middle of the adsorption chamber.

4. A device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system according to claim 2, Features: A circulation heater is provided in the heating chamber, and the temperature in the heating chamber is set at 600-800°C.

5. A device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system according to claim 1, Features: SO 2 The alarm concentration of sensor one is 2000ppm.

6. A device for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system according to claim 1, Features: The temperature difference between the temperature sensor 1 and the temperature sensor 2 is within 0°C-5°C.

7. A method for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system, Features: The device described in any one of claims 1 to 6 is used to reduce the sulfur poisoning failure rate of a diesel engine aftertreatment system.

8. A method for reducing the sulfur poisoning failure rate of a diesel engine aftertreatment system according to claim 7, Features: The specific steps include: S1, pass the exhaust gas of the diesel engine into the ventilation pipeline, through SO 2 Sensor 1 monitors SO in exhaust gas 2 concentration; S2, if SO 2 When the concentration is lower than the alarm concentration, the adsorption desulfurization device will not be started, and the exhaust gas will directly pass through the adsorption desulfurization device, and then be processed through the oxidation catalytic converter, particulate filter and selective catalytic reduction device in sequence; S3, if SO 2 When the concentration is higher than the alarm concentration, the adsorption desulfurization device is started, and the tail gas absorbs and desulfurizes in the adsorption desulfurization device to remove SO 2 , and then processed through an oxidation catalytic converter, a particulate filter and a selective catalytic reduction device.

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