Device for removing field VOCs (Volatile Organic Compounds)

Abstract

A device for removing on-site VOCs comprises an air cooling device, a filtering device, a deacidification device, a cold drying device and an adsorption device, the air cooling device can condense most of water vapor and part of oil mist steam in mixed gas into liquid to be discharged, the deacidification device comprises a spraying tower and other equipment, most of acid gas and a small amount of remaining oil mist steam can be removed, and the adsorption device is used for adsorbing VOCs. The cold drying device is located behind the deacidification device and condenses residual moisture in gas into water under the refrigeration effect to be discharged, the filtering device is located in front of the deacidification device and can remove most of dust and oil mist steam, and the adsorption device is located behind the cold drying device, comprises two activated carbon box sets, can be alternately used and can further remove VOCs gas.

Description

Technical Field

[0001] The invention relates to a device for removing VOCs on site in the field of petroleum technology, specifically to the recovery and treatment of VOCs gas at the oil pipe cleaning operation site, and finally to emission standards. Background Art

[0002] Oil pipes and sucker rods are essential materials for oil field and oil well production. After each oil well production operation, many sucker rods and oil pipes with oil sludge will be pulled out. These oil pipe rods need to be heated and cleaned at high temperature before they can be lowered into the well again. Since the oil pipe rods are cleaned at high temperature, a lot of toxic gases containing VOCs such as hydrogen sulfide will be generated. If these gases are discharged into the atmosphere without treatment, they will cause great harm to human health. The current cleaning process has not effectively treated this type of waste gas and cannot meet the emission standards. Summary of the invention

[0003] In view of the above problems, the present invention provides a device for removing VOCs on site, which can effectively solve the problem of meeting the emission standards of toxic gases generated during the cleaning of oil pipes and rods.

[0004] The technical solution of the present invention is to provide a device for removing VOCs on site, including an air cooling device, a filtering device, an acid removal device, a cold drying device and an adsorption device. The air cooling device can condense most of the water vapor and part of the oil mist vapor in the mixed gas into liquid for discharge. The acid removal device includes equipment such as a spray tower, which can remove most of the acid gas and the remaining small amount of oil mist vapor. The cold drying device is located after the acid removal device, and condenses the remaining water in the gas into water for discharge under the refrigeration effect. The filtering device is located before the acid removal device, and can remove most of the dust and oil mist vapor. The adsorption device is located after the cold drying device, and includes two groups of activated carbon box groups, which can be used alternately to further remove VOCs gas. The air cooling device comprises an air cooler with a drain outlet at the rear, which is connected to a filter device with several layers of filter cotton and filter boxes inside through a pipeline. The acid removal device comprises a spray tower and a grid arranged in the middle of the tower in a horizontal direction, an alkaline liquid that can be accommodated at the bottom of the tower, an alkaline liquid spray inlet located at the top of the tower, and an alkaline liquid overflow port located at the lower end of the tower. The filter device is connected to the spray tower after being connected to the air pump I through a pipeline and extends below the alkaline liquid level inside the tower. The cold drying device comprises a cold dryer and a drain outlet. A spirally arranged refrigeration copper tube is arranged inside the cold dryer. The cold drying device is connected to the adsorption device through a pipeline. The adsorption device comprises an activated carbon box group I, an activated carbon box group II, and two adsorption devices located at both ends of the activated carbon box group I. The carbon changing valve group I and the carbon changing valve group II at both ends of the activated carbon box group II, the two groups of activated carbon boxes can be used alternately. When maintaining the activated carbon box group I, close the carbon changing valve group I on both sides and open the carbon changing valve group II; when maintaining the activated carbon box group II, close the carbon changing valve group II and open the carbon changing valve group I. Each group of activated carbon box groups is composed of several levels of activated carbon boxes in series. The treated gas enters the emission chimney through the air outlet under the pumping of the air pump II. A special detection port is set in the front of the air outlet. The activated carbon box group includes: a box wall, an inlet flange and a Tesla reflux pipe connected by a main line, an activated carbon adsorption component and an outlet flange. The VOCs mixed gas enters the air cooler from the air inlet. Most of the water vapor and part of the mixed gas The oil mist vapor condenses into liquid and is discharged from the drain port, and the remaining gas enters the filter box along the pipeline. There are several layers of filter cotton in the filter box to remove most of the dust and oil mist vapor. The remaining gas enters the spray tower under the pumping of the air pump I. The bottom of the spray tower contains alkaline liquid. The air pump outlet is inserted below the alkaline liquid level. An overflow port is provided at the designed liquid level of the spray tower. Its function is to flow the excess alkaline liquid back into the collection box through the overflow port. The remaining gas enters the cold dryer. When the gas flows through the cold dryer, the remaining moisture is condensed into water and discharged from the drain port. The remaining gas enters the activated carbon box group I and the activated carbon box group II through the pipeline. The two are used alternately. When maintaining the activated carbon box group I, close the carbon replacement valve group I on both sides and open the carbon replacement valve group II;When maintaining the activated carbon box group II, close the carbon replacement valve group II and open the carbon replacement valve group I. Each group of activated carbon boxes is composed of several levels of activated carbon boxes connected in series. The treated gas enters the exhaust chimney through the outlet under the pumping of the air pump II. A special detection port is set in front of the outlet. ; BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 This is a flow chart of a method and device for removing VOCs on site according to the present invention.

[0006] Figure 2 This is a schematic diagram of the internal structure of the activated carbon box group of the present invention.

[0007] In the figure: 1-air cooler; 2-filter box; 3-air pump I; 4-spray tower; 5-cold dryer; 6-activated carbon box group I; 7-activated carbon box group II; 8-carbon change valve group I; 9-carbon change valve group II; 10-air pump II; 11-air inlet; 12-drain outlet a; 13-special detection port; 14-air outlet; 21-filter cotton; 41-alkaline liquid; 42-alkaline liquid overflow port; 43-grid; 44-alkaline liquid spray inlet; 51-refrigeration copper pipe; 52-drain outlet b; 61-inlet flange; 62-Tesla reflux pipe; 63-main line; 64-box wall; 65-activated carbon adsorption component; 66-outlet flange. DETAILED DESCRIPTION

[0008] A device for removing VOCs on site, including an air cooling device, a filtering device, an acid removal device, a cold drying device and an adsorption device. The air cooling device can condense most of the water vapor and part of the oil mist vapor in the mixed gas into liquid for discharge. The acid removal device includes equipment such as a spray tower, which can remove most of the acid gas and the remaining small amount of oil mist vapor. The cold drying device is located after the acid removal device, and condenses the remaining water in the gas into water for discharge under the refrigeration effect. The filtering device is located before the acid removal device, and can remove most of the dust and oil mist vapor. The adsorption device is located after the cold drying device, and includes two groups of activated carbon box groups. , can be used alternately, can further remove VOCs gas, VOCs mixed gas enters the air cooler 1 from the air inlet 11, most of the water vapor and part of the oil mist vapor in the mixed gas are condensed into liquid and discharged from the drain port a12, the remaining gas enters the filter box 2, the filter box 2 is provided with several layers of filter cotton 21, the filter cotton can be withdrawn and replaced at any time, the filter box can remove most of the dust and oil mist vapor, the remaining gas enters the spray tower 4 under the pumping of the air pump I, the function of the spray tower is to remove acid (containing hydrogen sulfide), the bottom of the spray tower has an alkaline liquid 41 (the commonly used alkaline liquid is lime water), and the air pump outlet is inserted below the alkaline liquid level. The top of the spray tower is provided with an alkaline liquid spray inlet 44, and the middle is provided with several layers of oppositely arranged grids 43, the function of which is to increase the gas flow distance, increase the contact time between the acid gas and the alkaline liquid, and improve the removal effect. An overflow port 42 is provided at the design liquid level of the spray tower, and its function is to flow the excess alkaline liquid back into the collection box through the overflow port to maintain the height of the alkaline liquid at the bottom. The spray tower can remove most of the acidic gas and the remaining small amount of oil mist vapor. The remaining gas enters the cold dryer 5 along the pipeline. The cold dryer maintains a low temperature under the action of the refrigeration copper tube. When the gas flows through the cold dryer, the remaining moisture will condense into water and be discharged from the drain port b52. The remaining gas enters the activated carbon box group. The activated carbon box group is divided into two groups: activated carbon box group I6 and activated carbon box group II7. The two are used alternately to ensure that they are While one group is being maintained, the other group can work normally. When maintaining the activated carbon box group I6, close the carbon replacement valve groups I8 on both sides and open the carbon replacement valve group 9; when maintaining the activated carbon box group II7, close the carbon replacement valve group II9 and open the carbon replacement valve group I8 to complete the alternating maintenance. Each group of activated carbon box groups can be composed of several levels of activated carbon boxes connected in series (2 levels are shown in the figure). The treated gas enters the exhaust chimney through the outlet 14 under the pumping of the air pump 10, and a special detection port 13 is set in the front part of the outlet to facilitate the instrument to detect the components of the gas. The special structure inside the activated carbon box group is as follows Figure 2As shown, the gas enters the activated carbon box group from the inlet flange 61 and flows in the main line 63. When flowing through the Tesla return pipe 62, part of the gas enters the Tesla return pipe 62. The Tesla return pipe is a semi-loop formed by bending the pipeline. According to the Tesla valve mechanism, due to the existence of the Tesla return pipe, the airflow in the main line receives anisotropic resistance during the flow, the flow velocity is reduced, and the residence time of the low-speed flowing gas after entering the activated carbon adsorption component 65 is prolonged, and the gas exchange time is increased, which greatly improves the adsorption effect of the activated carbon on VOCs gas.

Claims

1. A device for removing VOCs on site, characterized in that: It includes an air cooling device, a filtering device, an acid removal device, a cold drying device and an adsorption device. The acid removal device includes a spray tower and other equipment. The cold drying device is located after the acid removal device, the filtering device is located before the acid removal device, and the adsorption device is located after the cold drying device. It includes two groups of activated carbon boxes, which can be used alternately.

2. The device for removing VOCs on site according to claim 1, characterized in that: The air cooling device comprises an air cooler (1) with a water outlet a (12) at the rear, which is connected to a filter device of a filter box (2) with a plurality of layers of filter cotton (21) arranged inside through a pipeline.

3. The device for removing VOCs on site according to claim 1, characterized in that: The acid removal device comprises a spray tower (4), a grid (43) is arranged in the middle of the tower in the horizontal direction, the bottom of the tower can accommodate alkaline liquid (41), the alkaline liquid spray inlet (44) is located at the top of the tower, the alkaline liquid overflow port (42) is located at the lower end of the tower, and the filtering device is connected to the spray tower after being connected to the air pump I (3) through a pipeline and extends below the alkaline liquid level in the tower.

4. The device for removing VOCs on site according to claim 1, characterized in that: The cold drying device comprises a cold drying machine (5) and a drain outlet b (52). A spirally arranged refrigeration copper tube (51) is provided inside the cold drying machine (5). The cold drying device is connected to the adsorption device via a pipeline.

5. The device for removing VOCs on site according to claim 1, characterized in that: The adsorption device comprises an activated carbon box group I (6), an activated carbon box group II (7), a carbon replacement valve group I (8) located at both ends of the activated carbon box group I (6), and a carbon replacement valve group II (9) located at both ends of the activated carbon box group II (7). The two groups of activated carbon boxes can be used alternately.

6. The device for removing VOCs on site according to claim 5, characterized in that: The activated carbon box assembly comprises: a box wall (64), an inlet flange (61), a Tesla reflux pipe (62) and an activated carbon adsorption assembly (65) and an outlet flange (66) located in the box and connected via a main line (63).

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