Apparatus for removing trace amounts of methanol and acetaldehyde from carbon dioxide

Abstract

The utility model provides a device of removing trace methanol and acetaldehyde in carbon dioxide, including pressurizing unit, CO2 raw material gas entrance and oxygen entrance are provided to pressurizing unit, with the desulfurizing tower that pressurizing unit is connected, with the demethanol and acetaldehyde unit that desulfurizing tower is connected, with the flow path automatic switching unit that demethanol and acetaldehyde unit are connected, with the liquefaction unit that flow path automatic switching unit is connected, the utility model provides a device is CO2 raw material gas and oxygen mixed into pressurizing device, and after pressurizing, the gas is in desulfurizing tower and desulfurizes, then, after removing CO, methane, water, methanol and acetaldehyde unit removes, through on -line detection unit, the gas that meets control index enters liquefaction unit, and the unqualified gas returns pressurizing unit through flow path automatic switching unit, and the liquefied carbon dioxide gas is according to customer needs and is packed as finished product according to different grades.

Description

Technical Field

[0001] This utility model belongs to the technical field of carbon dioxide gas treatment devices, and particularly relates to a device for removing trace amounts of methanol and acetaldehyde from carbon dioxide. Background Technology

[0002] Currently, coal chemical and petrochemical waste gases contain a large amount of CO2 gas, which can be recovered and purified to produce industrial-grade and food-grade carbon dioxide. Coal chemical waste gas contains CO, methane, sulfur, cyanide, water, and ammonia; petrochemical processes, primarily the ethylene oxidation process, produce CO2 as a byproduct, which also contains small amounts of CO, CH4, methanol, acetaldehyde, ethylene oxide, and water. Therefore, when recovering and purifying CO2 from coal chemical and petrochemical waste gases, a removal process is necessary to remove CO, methane, sulfur, cyanide, ammonia, methanol, acetaldehyde, and water. Food-grade products have very high requirements: CO and methanol <10 ppm, acetaldehyde <0.2 ppm, CO <10 ppm, methane <50 ppm, ammonia and cyanide <2.5 ppm, and water <20 ppm. Methanol and acetaldehyde in the ethylene oxidation waste gas have strong adsorption properties and are difficult to remove using conventional methods. Utility Model Content

[0003] In view of this, the purpose of this utility model is to provide a device for removing trace amounts of methanol and acetaldehyde from carbon dioxide, which has a high removal rate of methanol and acetaldehyde.

[0004] This utility model provides a device for removing trace amounts of methanol and acetaldehyde from carbon dioxide, including a pressurization unit, wherein the pressurization unit is provided with a CO2 feed gas inlet and an oxygen inlet;

[0005] The desulfurization tower connected to the pressurization unit;

[0006] The methanol and acetaldehyde removal unit is connected to the desulfurization tower;

[0007] Automatic flow path switching unit connected to the methanol removal and acetaldehyde removal unit;

[0008] A liquefaction unit connected to the automatic flow path switching unit.

[0009] In a specific embodiment of this utility model, the pressurization unit is equipped with a piston compressor and a gas-liquid separator;

[0010] The gas-liquid separator can separate saturated water from CO2 feed gas.

[0011] In a specific embodiment of this utility model, the automatic flow path switching unit is connected to the pressurization unit via a pipeline.

[0012] In a specific embodiment of this utility model, an online detection unit is connected between the methanol removal and acetaldehyde removal unit and the automatic flow path switching unit.

[0013] In a specific embodiment of this utility model, the desulfurization tower is provided with a desulfurizing agent;

[0014] The desulfurizing agent is selected from coconut shell or activated carbon.

[0015] In a specific embodiment of this utility model, the methanol and acetaldehyde removal unit includes a reaction vessel connected to the desulfurization tower;

[0016] A drying tower connected to the reactor;

[0017] A purification tower connected to the drying tower.

[0018] In a specific embodiment of this utility model, a catalyst is provided in the reaction vessel;

[0019] The catalyst is a dehydrocarbonization catalyst.

[0020] In a specific embodiment of this utility model, the CO2 feed gas is obtained by ethylene oxidation.

[0021] This invention provides a device for removing trace amounts of methanol and acetaldehyde from carbon dioxide, comprising a pressurization unit with a CO2 feed gas inlet and an oxygen inlet; a desulfurization tower connected to the pressurization unit; a methanol and acetaldehyde removal unit connected to the desulfurization tower; an automatic flow path switching unit connected to the methanol and acetaldehyde removal unit; and a liquefaction unit connected to the automatic flow path switching unit. In this device, CO2 feed gas and oxygen are mixed and fed into the pressurization unit. The pressurized gas then enters the desulfurization tower for desulfurization, and then passes through the methanol and acetaldehyde removal unit to remove CO, methane, water, methanol, and acetaldehyde. After passing through an online detection unit, gas meeting control parameters enters the liquefaction unit, while unqualified gas is returned to the pressurization unit via the automatic flow path switching unit. The liquefied carbon dioxide gas is packaged into finished products according to different grades based on customer needs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the device for removing trace amounts of methanol and acetaldehyde from carbon dioxide provided by this utility model. Detailed Implementation

[0023] This utility model provides a device for removing trace amounts of methanol and acetaldehyde from carbon dioxide, including a pressurization unit, wherein the pressurization unit is provided with a CO2 feed gas inlet and an oxygen inlet;

[0024] The desulfurization tower connected to the pressurization unit;

[0025] The methanol and acetaldehyde removal unit is connected to the desulfurization tower;

[0026] Automatic flow path switching unit connected to the methanol removal and acetaldehyde removal unit;

[0027] A liquefaction unit connected to the automatic flow path switching unit.

[0028] The device provided by this utility model includes a pressurizing unit; the pressurizing unit pressurizes the mixture of raw material gas and oxygen to 1.9-2.2 MPa; in a specific embodiment, the pressurization is to 2 MPa. In this utility model, the CO2 raw material gas is obtained by ethylene oxidation.

[0029] The pressurization unit includes a piston compressor and a gas-liquid separator; the gas-liquid separator can separate saturated water from the CO2 feed gas. The gas-liquid separator is preferably configured as a two-stage system.

[0030] The pressurization unit is equipped with a CO2 feed gas inlet and an oxygen inlet; the CO2 feed gas and oxygen are mixed and then enter the reciprocating compressor. In this invention, the CO2 feed gas is generated by the ethylene oxidation process and contains small amounts of CO, CH4, methanol, acetaldehyde, ethylene oxide, and water. After being pressurized by the reciprocating compressor, the feed gas is sent to a gas-liquid separator for gas-liquid separation to remove saturated water, and then sent to the desulfurization tower.

[0031] The device provided by this utility model includes a desulfurization tower connected to the pressurization unit. The desulfurization tower contains a desulfurizing agent, which is selected from coconut shells or activated carbon; both are commercially available products. The desulfurization tower removes sulfur from the raw gas. The volume of the desulfurization tower is designed according to the sulfur removal rate.

[0032] The apparatus provided by this utility model includes a methanol and acetaldehyde removal unit connected to the desulfurization tower. The methanol and acetaldehyde removal unit includes a reaction vessel connected to the desulfurization tower.

[0033] A drying tower connected to the reactor;

[0034] A purification tower connected to the drying tower.

[0035] The methanol and acetaldehyde removal unit includes heating, catalytic reaction, drying, and purification steps. The catalytic reaction is carried out in a reaction vessel equipped with a catalyst to remove CO, methane, methanol, and acetaldehyde from the CO2 feed gas. The catalyst is selected from dehydrocarbonation catalysts, and the catalyst meets the requirements for precious metal content (Pd+Pt>0.15%wt(±5%)). In a specific embodiment, the dehydrocarbonation catalyst is model CC-20. Water produced in the reaction and water entering the unit are removed by a drying tower. Small amounts of oxygen and methane are removed by a purification tower.

[0036] The device provided by this utility model includes an automatic flow path switching unit connected to the methanol and acetaldehyde removal unit. The automatic flow path switching unit has signal receiving, data judgment, and execution functions. When the detection data is deemed unqualified, the automatic switching device will remove the gas from the methanol and acetaldehyde removal units. The unqualified gas is returned to the pressurization unit through the automatic flow path switching unit.

[0037] The device provided by this utility model also includes an online detection unit connecting the methanol and acetaldehyde removal unit and the automatic flow path switching unit. The online detection unit is an online analyzer; the online analyzer mainly consists of a moisture analyzer, a chromatograph, a total hydrocarbon analyzer, a trace oxygen analyzer, and a total sulfur analyzer, which detects the gas exiting the methanol and acetaldehyde removal unit, and sends the detection data to the automatic flow path switching device.

[0038] The device provided by this utility model includes a liquefaction unit connected to the automatic flow path switching unit. The liquefaction unit primarily liquefies qualified carbon dioxide gas into a liquid state, and can be packaged according to different grades as needed by the customer.

[0039] The device provided by this utility model has a high degree of automation and requires little equipment maintenance; it also has a high removal rate of methanol and acetaldehyde from carbon dioxide feed gas and a short process time.

[0040] The removal rates of methanol and acetaldehyde in this invention are calculated according to the following method:

[0041] First, test the methanol and acetaldehyde content in the raw gas separately. Then, test the methanol and acetaldehyde content in the gas after treatment by the removal device separately. The result of the latter test is divided by the result of the former test multiplied by 100%, and recorded as X. Then, 1-X is the removal rate.

[0042] To further illustrate this utility model, the following detailed description of the apparatus for removing trace amounts of methanol and acetaldehyde from carbon dioxide is provided in conjunction with the embodiments, but these descriptions should not be construed as limiting the scope of protection of this utility model.

[0043] In the following examples, the dehydrocarbonization catalyst was purchased from Jiangxi Zhongke Kairui Environmental Catalysis Co., Ltd.

[0044] Example 1

[0045] The CO2 feed gas produced by the ethylene oxidation process is mixed with oxygen and then compressed into a reciprocating compressor to 2 MPa. The gas then passes through a two-stage gas-liquid separator to separate the saturated water. The CO2 feed gas contains small amounts of CO, CH4, methanol, acetaldehyde, ethylene oxide, and water.

[0046] Then it enters the desulfurization tower for desulfurization, which contains coconut shells as a desulfurizing agent;

[0047] After desulfurization, the product enters the reactor of the methanol and acetaldehyde removal unit. The reactor is equipped with a dehydrocarbonization catalyst CC-20 to remove CO, methane, methanol and acetaldehyde. The water produced in the reaction and the water entering the unit enter the drying tower to remove moisture. Small amounts of oxygen and methane are removed through the purification tower.

[0048] After being processed by the methanol and acetaldehyde removal units, the gas is tested by an online analyzer. The test data is then sent to the automatic flow path switching unit. If the test data is deemed unqualified, the gas is returned to the pressurization unit. The qualified gas is then liquefied, and the liquefied carbon dioxide is packaged into finished products according to different grades based on customer needs.

[0049] The device achieves a methanol removal rate of 99.9999% and an acetaldehyde removal rate of 99.9999%.

[0050] As shown in the above embodiments, this utility model provides a device for removing trace amounts of methanol and acetaldehyde from carbon dioxide. The device includes a pressurization unit with a CO2 feed gas inlet and an oxygen inlet; a desulfurization tower connected to the pressurization unit; a methanol and acetaldehyde removal unit connected to the desulfurization tower; an automatic flow path switching unit connected to the methanol and acetaldehyde removal unit; and a liquefaction unit connected to the automatic flow path switching unit. In this device, CO2 feed gas and oxygen are mixed and fed into the pressurization unit. The pressurized gas then enters the desulfurization tower for desulfurization, and then passes through the methanol and acetaldehyde removal unit to remove CO, methane, water, methanol, and acetaldehyde. After passing through an online detection unit, gas meeting the control indicators enters the liquefaction unit, while unqualified gas returns to the pressurization unit via the automatic flow path switching unit. The liquefied carbon dioxide gas is packaged into finished products according to different grades based on customer needs. Experimental results show that the methanol removal rate of this device is 99.9999–100%, and the acetaldehyde removal rate is 99.9999–100%.

[0051] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An apparatus for removing trace amounts of methanol and acetaldehyde from carbon dioxide, characterized in that, It includes a pressurization unit, which is provided with a CO2 feed gas inlet and an oxygen inlet; The desulfurization tower connected to the pressurization unit; The methanol and acetaldehyde removal unit is connected to the desulfurization tower; Automatic flow path switching unit connected to the methanol removal and acetaldehyde removal unit; A liquefaction unit connected to the automatic flow path switching unit.

2. The apparatus according to claim 1, characterized in that, The pressurization unit is equipped with a piston compressor and a gas-liquid separator; The gas-liquid separator can separate saturated water from CO2 feed gas.

3. The apparatus according to claim 1, characterized in that, The automatic flow path switching unit is connected to the pressurization unit via pipeline.

4. The apparatus according to claim 1, characterized in that, The online detection unit is connected between the methanol removal and acetaldehyde removal unit and the automatic flow path switching unit.

5. The apparatus according to claim 1, characterized in that, The desulfurization tower contains a desulfurizing agent.

6. The apparatus according to claim 5, characterized in that, The desulfurizing agent is selected from coconut shell or activated carbon.

7. The apparatus according to claim 1, characterized in that, The methanol and acetaldehyde removal unit includes a reaction vessel connected to the desulfurization tower; A drying tower connected to the reactor; A purification tower connected to the drying tower.

8. The apparatus according to claim 7, characterized in that, The reactor contains a catalyst.

9. The apparatus according to claim 8, characterized in that, The catalyst is a dehydrocarbonization catalyst.

10. The apparatus according to claim 1, characterized in that, The CO2 feed gas was obtained by the ethylene oxidation process.

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