Catalytic combustion device for regenerated tail gas of MTO (Methanol To Olefins) gas-liquid dryer

Abstract

The utility model discloses an MTO gas-liquid dryer regeneration tail gas catalytic combustion device which comprises a gas-liquid phase dryer, a catalytic combustion device and a heat exchanger, regeneration tail gas enters the catalytic combustion device, and gas after catalytic oxidation enters the heat exchanger for heat exchange and then is discharged. The catalytic combustion device comprises a heating area, a catalysis area and a ceramic material filling layer; the heating area is filled with layered honeycomb ceramics, and regenerated tail gas and air are premixed and heated; the catalytic area comprises a catalyst layer, and mixed gas of regenerated tail gas and air enters the catalyst layer for catalytic combustion and is decomposed into carbon dioxide and water; the ceramic material filling layer is filled with heat storage ceramics, serves as a heat storage body and a heat exchange area, and absorbs heat released by catalytic combustion reaction. According to the device disclosed by the utility model, the regenerated tail gas is subjected to catalytic combustion treatment, organic matters are decomposed into CO2 and H2O, and the situation that VOCS (Volatile Organic Chloride) exceeds the standard when the regenerated tail gas enters a torch is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of olefin separation technology in methanol-to-olefins (MTO), specifically relating to a catalytic combustion device for regenerating tail gas in an MTO gas-liquid dryer. Background Technology

[0002] After acidic oxides are removed from the product gas of the MTO unit, it is cooled by propylene refrigerant and separated into two different phases: a gaseous phase and a liquid phase. The gaseous phase enters a gaseous product dryer, and the liquid phase enters a liquid phase product dryer. The gaseous and liquid phase dryers remove moisture from the materials to prevent freezing and blockage when entering subsequent separation systems. The drying system mainly pre-treats the downstream cryogenic process. This area includes two OPU gaseous product dryers and corresponding regeneration units, as well as two OPU liquid product dryers and corresponding regeneration systems. The dryers use molecular sieves to remove almost all water. The regeneration systems of the gaseous and liquid phase dryers include a regeneration heater, a regeneration cooler, and a regeneration separator. After separation from free water, the regeneration gas is sent to the flare system. The dried gaseous and liquid phase products are sent to a high-pressure propane stripper for further separation.

[0003] Currently, the regeneration exhaust gas from the MTO gas-liquid dryer is directly discharged into the flare system. The discharged exhaust gas contains a large amount of C2 to C7 components (ethylene, ethane, propyne, propylene, propane, n-hexane, and n-heptane). Direct discharge will cause incomplete combustion in the flare, excessive VOCs emissions, and environmental pollution. Summary of the Invention

[0004] The purpose of this invention is to provide a catalytic combustion device for the regenerated tail gas of an MTO gas-liquid dryer, which solves the technical problem of direct emission of regenerated tail gas. By treating the regenerated tail gas with catalytic combustion, organic matter is converted into CO2 and H2O and heat is released to achieve the expected treatment effect and ensure that there are no pollutants at the emission outlet.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this utility model is as follows:

[0006] A catalytic combustion device for regenerated tail gas of MTO gas-liquid dryer includes a gas-liquid phase dryer, characterized in that it further includes a catalytic combustion device and a heat exchanger. The regenerated tail gas of the gas-liquid phase dryer enters the catalytic combustion device, and the gas after catalytic oxidation enters the heat exchanger for heat exchange before being discharged.

[0007] The catalytic combustion device includes a heating zone, a catalytic zone, and a ceramic material filling layer. The heating zone is filled with layered honeycomb ceramic to premix and heat the regenerated exhaust gas and air. The catalytic zone includes a catalyst layer, into which the regenerated exhaust gas and air mixture enters for catalytic combustion, decomposing into carbon dioxide and water. The ceramic material filling layer is filled with heat-storing ceramic, serving as a heat storage body and heat exchange zone to absorb the heat released by the catalytic combustion reaction and reduce the exhaust gas temperature.

[0008] After catalytic oxidation, the gas leaving the catalytic combustion unit can be directly discharged into the atmosphere after recovering its heat energy through a heat exchanger. The temperature of the purified exhaust gas is only slightly higher than that before the regeneration gas treatment, which can maintain the VOCs at the flare plant boundary within the standard, meet the high requirements of environmental management, and reduce the possibility of VOCs exceeding the standard caused by the regeneration tail gas from the gas-liquid phase dryer entering the flare.

[0009] Furthermore, the heating zone of the catalytic combustion device can be heated by electric heating or natural gas heating.

[0010] Furthermore, the catalytic combustion temperature of the catalytic combustion device, i.e. the temperature of the catalytic zone, is 300–700°C.

[0011] Furthermore, the device also includes a blower that supplies air into the catalytic combustion device.

[0012] The blower is a centrifugal compressor that compresses air and sends it to the catalytic combustion device to provide sufficient oxygen, so that the organic matter in the exhaust gas can be fully burned and decomposed to produce carbon dioxide and water.

[0013] Furthermore, a VOCs detection instrument is installed after the heat exchanger to ensure that the emissions of non-methane total hydrocarbons meet the standards.

[0014] Beneficial effects: This utility model's MTO gas-liquid dryer regeneration tail gas catalytic combustion device reduces the emission of gas-liquid dryer regeneration tail gas to the flare system. The regeneration tail gas is heated before being sent to the catalytic combustion device. The tail gas entering the catalytic combustion device is preheated in the heating zone, and then enters the catalytic layer for reaction. The organic matter in the preheated tail gas is ultimately converted into CO2 and H2O. The decomposed tail gas is then discharged into the atmosphere after heat recovery. A VOCs detector is installed at the outlet to ensure that the emission of non-methane total hydrocarbons meets standards. This prevents incomplete combustion in the flare and ensures environmental compliance. Attached Figure Description

[0015] Figure 1 This utility model provides a structural schematic diagram of an MTO gas-liquid dryer regenerated tail gas catalytic combustion device.

[0016] In the diagram, 1-catalytic combustion device, 2-regeneration tail gas regulating valve, 3-fan inlet valve, 4-regeneration gas inlet valve, 5-heat exchanger, 6-gas-liquid phase dryer, 7-blower, 8-tail gas emission valve;

[0017] Figure 2 Schematic diagram of a catalytic combustion device;

[0018] In the diagram, 10-ceramic material filling layer (bottom layer), 11-catalytic zone (middle layer), 12-heating zone (top layer), 13-heating lamp or burner, 14-regenerated exhaust gas inlet, 15-air inlet, and 16-exhaust gas outlet. Detailed Implementation

[0019] The specific embodiments of this utility model will be described in detail below. However, it should be noted that the scope of protection of this utility model is not limited by these specific embodiments, but is determined by the claims.

[0020] like Figure 1 As shown, this utility model discloses an MTO gas-liquid dryer regeneration tail gas catalytic combustion device, including a gas-liquid dryer 6, a catalytic combustion device 1, a heat exchanger 5, a blower 7, etc. The regeneration gas is controlled by the regeneration gas inlet valve 4 and enters the gas-liquid dryer 6. The generated regeneration tail gas enters the catalytic combustion device 1, and the regeneration tail gas flow rate is regulated by the regeneration tail gas regulating valve 2. The regeneration tail gas undergoes catalytic combustion in the catalytic combustion device 1, where the organic matter ultimately generates CO2 and H2O. The required oxygen is supplied to the catalytic combustion device 1 by the blower 7. The decomposed tail gas enters the heat exchanger 5, recovers heat energy, and is then discharged into the atmosphere through the tail gas emission valve 8.

[0021] According to the device of this invention, the exhaust temperature of the purified tail gas is only slightly higher than the temperature of the regenerated tail gas before treatment, thus recovering heat and reducing energy consumption. A VOCs detection instrument can be installed after the heat exchanger 5 and before the tail gas emission valve 8 to ensure that the emission of non-methane total hydrocarbons meets the standards. Through the device of this invention, the VOCs at the flare plant boundary can be kept within the standard, reducing the risk of exceeding the standard due to tail gas entering the flare and generating VOCs.

[0022] The catalytic combustion device 1 includes a ceramic material filling layer 10 (bottom layer), a catalytic zone 11 (middle layer), and a heating zone 12 (upper layer). The heating zone 12 includes a regenerated exhaust gas inlet 14, an air inlet 15, and a heating lamp or burner 13. The heating zone 12 is filled with layered honeycomb ceramic, which premixes and heats the regenerated exhaust gas and air. The ceramic material "stores" heat from the previous cycle, releases heat, and lowers its temperature, while the regenerated exhaust gas absorbs heat and rises in temperature. After leaving the heating zone 12, the regenerated exhaust gas enters the catalytic zone 11 at a higher temperature, the temperature of which depends on the volume of the ceramic body, the flow rate in the catalytic zone 11, and the geometry of the ceramic body. The catalytic zone 11 contains a catalyst layer. The mixture of regenerated exhaust gas and air enters the catalyst layer for catalytic combustion, where organic matter is oxidized and decomposed into carbon dioxide and water. Because the regenerated exhaust gas is preheated in the heating zone 12, the fuel consumption of the catalytic combustion device 1 is greatly reduced. The ceramic material filling layer 10 is filled with heat storage ceramic, which serves as a heat storage body and heat exchange zone to absorb the heat released by the catalytic combustion reaction and reduce the exhaust gas temperature.

[0023] The regenerated exhaust gas continuously passes through the heating zone 12, where it can be heated by electric heating or natural gas heating and maintained at the set temperature. After preheating, the regenerated exhaust gas reaches the temperature set for catalytic oxidation in the catalytic zone 11. Typically, the catalytic combustion temperature is 300–700°C. When the regenerated exhaust gas is introduced, the organic pollutants in it enter the catalytic layer to complete the catalytic oxidation reaction, decomposing into CO2 and H2O and releasing heat.

Claims

1. A catalytic combustion device for regenerating tail gas from an MTO gas-liquid dryer, comprising a gas-liquid phase dryer (6), characterized in that: It also includes a catalytic combustion device (1) and a heat exchanger (5). The gas-liquid phase dryer (6) regenerates the tail gas into the catalytic combustion device (1), and the gas after catalytic oxidation enters the heat exchanger (5) for heat exchange before being discharged. The catalytic combustion device (1) includes a heating zone (12), a catalytic zone (11), and a ceramic material filling layer (10). The heating zone (12) is filled with layered honeycomb ceramics to premix and heat the regenerated tail gas and air. The catalytic zone (11) contains a catalyst layer. The regenerated tail gas and air mixed gas enter the catalyst layer for catalytic combustion reaction. The ceramic material filling layer (10) is filled with heat storage ceramics to absorb the heat released by the catalytic combustion reaction.

2. The MTO gas-liquid dryer regeneration tail gas catalytic combustion device according to claim 1, characterized in that, The heating zone (12) of the catalytic combustion device (1) is heated by electric heating or natural gas heating.

3. The MTO gas-liquid dryer regeneration tail gas catalytic combustion device according to claim 1, characterized in that, The heating zone (12) of the catalytic combustion device (1) includes a regenerated exhaust gas inlet (14), an air inlet (15), and a continuous lamp or burner (13).

4. The MTO gas-liquid dryer regeneration tail gas catalytic combustion device according to claim 1, characterized in that, The temperature of the catalytic zone (11) of the catalytic combustion device (1) is 300-700℃.

5. The MTO gas-liquid dryer regeneration tail gas catalytic combustion device according to claim 1, characterized in that, The device also includes a blower (7) that delivers air into the catalytic combustion device (1).

6. The MTO gas-liquid dryer regeneration tail gas catalytic combustion device according to claim 5, characterized in that, The blower (7) is a centrifugal compressor that compresses air and sends it into the catalytic combustion device (1).

7. The MTO gas-liquid dryer regeneration tail gas catalytic combustion device according to claim 1, characterized in that, A VOCs detection instrument is installed after the heat exchanger (5).

Images