Treatment device and treatment method for drilling fluid waste gas

Abstract

The invention provides a treatment device and method for drilling fluid waste gas, the treatment device comprises a vibrating screen for receiving a mixture, a waste gas collecting branch pipe arranged on the vibrating screen, and a purification mechanism connected with the vibrating screen, the purification mechanism comprises a spraying box, a drying assembly, an adsorption box and an induced draft fan which are arranged below the vibrating screen in series, the circulating storage tank is arranged between the vibrating screen and the purifying mechanism, and the waste gas gathering manifold is arranged between the waste gas collecting branch pipe and the spraying box. The vibrating screen, the waste gas collecting branch pipes and the waste gas gathering manifold are integrally arranged, so that the normal use and moving capacity of the vibrating screen is improved, and drilling fluid waste gas at the screen mesh position of the vibrating screen can be sufficiently and quickly absorbed.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling environmental protection equipment, and particularly to a treatment device for drilling fluid exhaust gas and a treatment method for drilling fluid exhaust gas. Background Art

[0002] In the existing technology, the drilling fluids used in drilling sites are usually water-based drilling fluids and oil-based drilling fluids. Due to the use of alkaline treatment agents or mineral oil-based fluids, problems such as excessive emission of ammonia, alkaline gases, etc. and the problem of peculiar smell of volatile organic compounds (VOCs) have emerged. Since the shale shaker is a solids control equipment for purifying and treating drilling fluids, the problem of drilling fluid exhaust gas escaping at the shale shaker screen surface is the most serious during the treatment process.

[0003] Currently, the working principle of existing exhaust gas treatment devices is usually to collect gas by enclosure and cooperate with purification treatment, and then discharge the exhaust gas after meeting the standard requirements. Due to the characteristics of drilling engineering, such as relocation and field operation, the conventional gas collection equipment for exhaust gas treatment needs to enclose the shale shaker screen surface, which causes difficulties in disassembly, installation and maintenance of the equipment, and further affects the on-site workers' observation of the drilling fluid treatment situation. Therefore, it cannot be used at the drilling site.

[0004] Therefore, in this field, there is a need to provide a treatment device for drilling fluid exhaust gas to solve the above technical problems. Summary of the Invention

[0005] The object of the present invention is to provide a treatment device for drilling fluid exhaust gas, which integrates the shale shaker, the exhaust gas collection branch pipe and the exhaust gas summary pipe manifold, thereby not only improving the normal use and relocation operation ability of the shale shaker, but also ensuring that the drilling fluid exhaust gas at the shale shaker screen position can be fully and quickly absorbed, so as to further ensure that the drilling fluid exhaust gas discharged into the environment meets the emission standards.

[0006] According to a first aspect of the present invention, there is provided a shale shaker for receiving a mixture, which includes a shale shaker for receiving a mixture, and an exhaust gas collection branch pipe is provided on the shale shaker.

[0007] A purification mechanism connected to the shale shaker, which includes a spray box, a drying component, an adsorption box and a draft fan arranged in series below the shale shaker.

[0008] A circulation storage tank provided between the shale shaker and the purification mechanism, and

[0009] An exhaust gas summary pipe manifold provided between the exhaust gas collection branch pipe and the spray box.

[0010] Among them, the mixture is separated under the action of the vibrating screen. After separation, the drilling fluid flows to the circulation storage tank, and the exhaust gas of the drilling fluid after separation flows to the exhaust gas collecting manifold through the exhaust gas collecting branch pipe.

[0011] In one embodiment, a spray liquid for absorbing the exhaust gas of the drilling fluid is accommodated in the spray box. The spray liquid is configured as an organic acid and includes any one of oleic acid, citric acid, and malic acid.

[0012] In one embodiment, the purification mechanism further includes a water tank disposed below the spray box and configured to receive the reacted spray liquid, and a valve body configured as a tee structure. Among them, the valve body includes a valve body inlet end connected to the water tank, a valve body outlet end for pumping the reacted spray liquid into the spray box, and a valve body circulation end for pumping the oil-water mixed emulsion formed by the spray liquid and the exhaust gas of the drilling fluid into the circulation storage tank.

[0013] In one embodiment, a sampling port for detecting the pH value of the spray liquid is provided on the water tank. The purification mechanism further includes a controller connected to the valve body. The controller is configured to:

[0014] When the pH value detected at the sampling port is less than 7, it can open the valve body outlet end to pump the spray liquid into the spray box.

[0015] When the pH value detected through the sampling port is greater than or equal to 7, it can open the valve body circulation end to pump the oil-water mixed emulsion into the circulation storage tank.

[0016] In one embodiment, the drying assembly includes a drying box, a pump body disposed at the outlet of the drying box, and a liquid level sensor disposed on the drying box. Among them, calcium chloride desiccant for drying the exhaust gas of the drilling fluid is accommodated in the drying box. The pump body is configured to be able to pump the calcium chloride solution into the circulation storage tank when the liquid level sensor reaches a predetermined value.

[0017] In one embodiment, an adsorbent is accommodated in the adsorption box. The adsorbent includes any one of honeycomb activated carbon, molecular sieve, and activated clay.

[0018] In one embodiment, a screen is provided at the bottom of the vibrating screen.

[0019] The treatment device further includes a mud inlet tank for injecting the mixture into the vibrating screen, and a diversion trough disposed in the vibrating screen and configured to guide the flow of the drilling fluid to the screen.

[0020] In one embodiment, the treatment device further includes a gas discharge manifold connected to the induced draft fan, and an exhaust gas concentration monitoring sensor provided on the induced draft fan.

[0021] According to a second aspect of the present invention, there is provided a method for treating drilling fluid exhaust gas by using the treatment device as described above, including the following steps:

[0022] S1. The mixture is separated by the vibrating screen, and the separated drilling fluid flows into the circulation storage tank. The separated drilling fluid exhaust gas sequentially passes through the exhaust gas collection branch pipe and the exhaust gas summary pipe manifold and enters the spray box.

[0023] S2. The drilling fluid exhaust gas is purified by the spray liquid in the spray box and then enters the drying box.

[0024] S3. The drilling fluid exhaust gas is dried by calcium chloride desiccant in the drying box and then enters the adsorption box, and is adsorbed by the adsorbent in the adsorption box and then discharged.

[0025] In one embodiment, purification step S201 is further included in S2:

[0026] First, the spray liquid in the spray box flows to the water tank after purifying the drilling fluid exhaust gas.

[0027] Then, the pH value of the liquid in the water tank is detected through the sampling port. If the pH value is less than 7, the controller needs to open the valve body outlet end to pump the spray liquid into the spray box; if the pH value is greater than or equal to 7, the controller needs to open the valve body circulation end to pump the oil-water mixed emulsion into the circulation storage tank.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] Firstly, by integrally arranging the vibrating screen, the exhaust gas collection branch pipe and the exhaust gas summary pipe manifold, the present invention not only improves the normal use and relocation operation ability of the vibrating screen, but also ensures that the drilling fluid exhaust gas at the screen position of the vibrating screen can be fully and quickly absorbed, so as to further ensure that the drilling fluid exhaust gas discharged into the environment meets the emission standards.

[0030] In addition, since both the vibrating screen and the exhaust gas summary pipe manifold are installed on the circulation storage tank, and the purification mechanism is located below the circulation storage tank, not only the total floor area of the entire device is effectively reduced, but also the drilling fluid exhaust gas can flow smoothly through reasonable layout, thereby improving the treatment efficiency of the purification mechanism for the drilling fluid exhaust gas.

[0031] Second, in the present invention, the spraying liquid (such as oleic acid) disposed in the spraying box reacts with alkaline gases such as ammonia gas to generate water and ammonium oleate dissolved in water. At the same time, as an organic acid, oleic acid can partially absorb the volatile VOCs gas in the oil-based drilling fluid and fix it in the liquid phase. Moreover, since the ammonium oleate aqueous solution in the spraying liquid can, on the premise that oleic acid is in excess, further react to form a relatively stable water-in-oil emulsion after oleic acid adsorbs the organic gas, and after the reaction is complete, the spraying liquid will become a milky oil-water mixed emulsion with an alkaline or neutral pH value.

[0032] In this way, not only can the drilling fluid waste gas passing through the spraying box be well purified to ensure that the subsequent discharged drilling fluid waste gas meets the emission standards, but also the oil-water mixed emulsion generated after the reaction is complete can act as a dispersant and a lubricant in the oil-based drilling fluid and the water-based drilling fluid respectively, thereby achieving the purpose of waste recycling and further solving the problems of limited sources of traditional inorganic acid spraying agents as hazardous chemicals, limited use in well sites, and difficult treatment of waste liquid after reaction.

[0033] Third, the present invention utilizes the characteristic that calcium chloride is extremely easy to absorb water as a desiccant, and in-situ uses the brine solution formed after its water absorption for the performance maintenance of the oil-based drilling fluid, so as to further achieve the purpose of waste recycling. In other words, the calcium chloride desiccant in the drying box will form brine containing calcium chloride after absorbing the liquid phase in the drilling fluid waste gas, and can be pumped into the circulation storage tank as brine and added to the oil-based drilling fluid or pumped into the water tank for temporary storage under the action of the pump body, so as to achieve the recycling of waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be described in detail below with reference to the drawings. In the drawings:

[0035] Figure 1 Schematically shows the structure of the device for treating drilling fluid waste gas;

[0036] Figure 1a Is the rear view of the device for treating drilling fluid waste gas;

[0037] Figure 2 Is a partial view of the device for treating drilling fluid waste gas according to the present invention, which shows the connection between the vibrating screen and the waste gas collecting manifold;

[0038] Figure 3 Is a partial view of the device for treating drilling fluid waste gas according to the present invention, which shows the structure of the purification mechanism.

[0039] In the drawings, the same components are denoted by the same reference numerals. The drawings are not drawn to actual scale. DETAILED DESCRIPTION OF THE INVENTION

[0040] In order to make the technical solutions and advantages of the present invention clearer and more understandable, the exemplary embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. And without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0041] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0042] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements.

[0043] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] The present invention will be further described below with reference to the accompanying drawings.

[0045] Figure 1 Schematically shows the structure of the treatment device 100 for drilling fluid exhaust gas;

[0046] Figure 1a Is the rear view of the treatment device for drilling fluid exhaust gas;

[0047] Figure 2 Is a partial view of the treatment device 100 for drilling fluid exhaust gas according to the present invention, which shows the connection between the vibrating screen 10 and the exhaust gas collecting manifold 30;

[0048] Figure 3 Is a partial view of the treatment device 100 for drilling fluid exhaust gas according to the present invention, which shows the structure of the purification mechanism.

[0049] As Figure 1 and 1a shown, according to the first aspect of the present invention, there is provided a treatment device 100 for drilling fluid exhaust gas, which includes a vibrating screen 10 for receiving a mixture, a purification mechanism connected to the vibrating screen 10, and a circulation storage tank 26. Among them, the purification mechanism includes a spray box 22 provided below the vibrating screen 10, and a blower 25 arranged in series with the spray box 22.

[0050] In the present invention, the mixture includes a solid phase, a liquid phase (drilling fluid), and a gas phase (drilling fluid exhaust gas). Preferably, the mixture can be subjected to solid-liquid-gas separation under the action of the vibrating screen 10. The separated solid phase stays within the vibrating screen 10, the separated drilling fluid flows into the circulation storage tank 26 for subsequent recycling, and the separated drilling fluid exhaust gas flows into the spray box 22 under the action of the induced draft fan 25.

[0051] In one embodiment, as Figure 1 shown, an exhaust gas collection branch pipe 102 is provided on the vibrating screen 10, and the treatment device 100 for drilling fluid exhaust gas further includes an exhaust gas manifold 30. Preferably, the exhaust gas manifold 30 is arranged between the exhaust gas collection branch pipe 102 and the spray box 22, so as to be able to fully and quickly absorb the drilling fluid exhaust gas at the position of the screen 101 of the vibrating screen 10 under the action of the induced draft fan 25.

[0052] In this way, the problem of the escape of the vibrating screen 10 can be reasonably solved, so as to achieve the purpose of avoiding environmental pollution caused by the escape of drilling fluid exhaust gas.

[0053] Since flange ports and quick connectors are provided at the ends of the exhaust gas manifold 30. Therefore, it can be quickly connected to the rear wall plate of the vibrating screen 10 through the flange ports, quick connectors or bolts, which further improves the working efficiency of the treatment device 100 for drilling fluid exhaust gas.

[0054] In the present invention, by integrally arranging the vibrating screen 10 and the exhaust gas manifold 30, it not only improves the normal use and relocation operation ability of the vibrating screen 10, but also ensures that the drilling fluid exhaust gas at the position of the screen 101 of the vibrating screen 10 can be fully and quickly absorbed, so as to further ensure that the drilling fluid exhaust gas discharged into the environment meets the emission standards.

[0055] In the present invention, as Figure 2 shown, the treatment device 100 for drilling fluid exhaust gas further includes a mud inlet tank 11 for injecting the mixture into the vibrating screen 10. Preferably, a diversion groove 12 for guiding the flow direction of the separated drilling fluid is provided within the vibrating screen 10, so as to be able to adjust the flow direction of the drilling fluid and effectively prevent the drilling fluid from splashing into the exhaust gas manifold 30.

[0056] In addition, since the exhaust gas manifold 30 is above the diversion groove 12, it can more easily and quickly absorb the drilling fluid exhaust gas at the position of the screen 101 of the vibrating screen 10, and thus can reasonably solve the problem of the escape of drilling fluid exhaust gas at the position of the screen 101 of the vibrating screen 10.

[0057] Preferably, the circulation storage tank 26 is arranged between the vibrating screen 10 and the purification mechanism. In the present invention, the vibrating screen 10 and the exhaust gas manifold 30 are integrally designed and are both installed on the circulation storage tank 26, while the purification mechanism is located below the circulation storage tank 26. In this way, the present invention not only effectively reduces the total floor area of the entire device, but also enables the drilling fluid exhaust gas to flow smoothly through a reasonable layout, thereby improving the treatment efficiency of the purification mechanism for the drilling fluid exhaust gas.

[0058] In an embodiment of the present invention, a spray liquid for absorbing the drilling fluid exhaust gas is accommodated in the spray box 22. Preferably, the spray liquid is configured as an organic acid, and its pH value is in the range of 3.5 to 5.

[0059] Due to the frequent use of alkaline treatment agents or mineral oil-based fluids in existing drilling operations, problems such as excessive emission of ammonia, alkaline gases, etc. and the problem of unpleasant odors of volatile organic compounds (VOCs) have emerged.

[0060] Therefore, the spray liquid (such as oleic acid) provided in the spray box 22 of the present invention can react with alkaline gases such as ammonia to generate water and ammonium oleate dissolved in water. At the same time, as an organic acid, oleic acid can partially absorb the volatile VOCs gas in the oil-based drilling fluid and fix it in the liquid phase. In this way, the drilling fluid exhaust gas passing through the spray box 22 can be well purified to ensure that the subsequent discharged drilling fluid exhaust gas meets the emission standards.

[0061] In addition, since the ammonium oleate aqueous solution in the spray liquid can, on the premise of excessive oleic acid, further react to form a relatively stable water-in-oil emulsion after the oleic acid adsorbs the organic gas, and after the reaction is complete, the spray liquid will become a milky oil-water mixed emulsion with a pH value of alkaline or neutral.

[0062] Preferably, the oil-water mixed emulsion generated after the reaction is complete can act as a dispersant and a lubricant in the oil-based drilling fluid and the water-based drilling fluid respectively, thereby achieving the purpose of waste reuse and further solving the problems of limited sources of traditional inorganic acid spray agents as hazardous chemicals, limited use in well sites, and difficult treatment of waste liquid after reaction.

[0063] According to the present invention, the purification mechanism further includes a water tank arranged below the spray box 22 and used to receive the reacted spray liquid and a valve body (not shown) configured as a tee structure. The valve body includes a valve body inlet end connected to the water tank, a valve body outlet end, and a valve body circulation end.

[0064] Preferably, the valve body inlet end of the valve body is connected to the spray box 22, and the valve body circulation end of the valve body is connected to the circulation storage tank 26. Correspondingly, water pumps (not shown) are provided between the valve body inlet end and the spray box 22 and between the valve body circulation end and the circulation storage tank 26.

[0065] In one embodiment, a sampling port for detecting the pH value of the spray liquid is provided on the water tank. And the purification mechanism further includes a controller (not shown) connected to the valve body.

[0066] In the present invention, the spray liquid after reacting with the drilling fluid waste gas will enter the water tank, and the pH value will be detected at the sampling port. The controller is configured to selectively open the inlet end or the circulation end of the control valve body according to the result of the pH value detection.

[0067] Preferably, when the pH value of the spray liquid detected at the sampling port does not meet the requirements (i.e., the pH value of the spray liquid is less than 7), the inlet end of the valve body is opened through the controller, so as to pump the reacted spray liquid into the spray tank 22 to continue the purification work of the drilling fluid waste gas.

[0068] Preferably, when the pH value of the spray liquid detected at the sampling port meets the requirements (i.e., the pH value of the spray liquid is greater than or equal to 7), the circulation end of the valve body is opened through the controller, so as to pump the oil-water mixed emulsion generated after the complete reaction of the spray liquid and the drilling fluid waste gas into the circulation storage tank 26, and it acts as a dispersant and a lubricant in the drilling fluid in the circulation storage tank 26 respectively, so as to achieve the purpose of waste recycling.

[0069] In the present invention, the spray liquid includes any one of oleic acid, citric acid and malic acid. The reaction conditions of different spray liquids are introduced below: Reaction of oleic acid and ammonia water:

[0070] CH3(CH2)7CH=CH(CH2)7COOH+NH3·H2O--->CH3(CH2)7CH=CH(CH2)7COONH4+H2O; Reaction of citric acid and ammonia water: NH3·H2O+C6H8O7→NH4C6H7O7+H2O

[0071] Reaction of malic acid and ammonia water: NH3·H2O+C4H6O5→NH4C4H5O5+H2O

[0072] Since traditional inorganic acid spray agents are usually regarded as dangerous chemicals, their sources are limited, their use on well sites is restricted, and the treatment of waste liquid after reaction is difficult. However, in the present invention, the traditional inorganic acid spray agent is replaced by an organic acid spray liquid, so as to react with the alkaline gas in the drilling fluid waste gas to achieve the purpose of adsorption, and the oil-water mixed emulsion generated after the complete reaction of the organic acid can act as a dispersant and a lubricant in oil-based drilling fluid and water-based drilling fluid respectively, so as to achieve the purpose of waste recycling.

[0073] In this way, not only the practical problems existing in the filing, storage and application of acidic hazardous chemicals at the drilling site are solved, but also the purpose of in-situ utilization can be achieved by adding the product in-situ into the drilling fluid as a functional component.

[0074] In a preferred embodiment, the function of the spray box 22 is to remove alkaline gases such as ammonia in the waste gas, and two-stage spray de-alkalization and three-layer demisting are provided in the spray box 22. In addition, after the spray liquid in the spray box 22 adsorbs part of the organic gas, the service life of the adsorbent in the subsequent adsorption box 42 (introduced below) can be extended.

[0075] According to the present invention, the purification mechanism further includes a drying component disposed between the spray box 22 and the induced draft fan 25. Preferably, as Figure 1 and 3 shown, the drying component includes a drying box 41, a pump body (not shown) disposed at the outlet of the drying box 41, and a liquid level sensor (not shown) disposed on the drying box 41. Among them, a microporous filter screen (not shown) for solid-liquid separation is provided in the drying box 41.

[0076] Preferably, the drilling fluid waste gas discharged from the spray box 22 will enter the drying box 41 under the action of the induced draft fan 25.

[0077] In the present invention, a four-layer demisting structure is provided in the drying box 41, and calcium chloride desiccant is filled in the four-layer demisting structure respectively, so as to perform a drying operation on the drilling fluid waste gas entering the drying box 41 to fully absorb the liquid phase in the drilling fluid waste gas.

[0078] Preferably, the calcium chloride desiccant will form a calcium chloride solution after absorbing the liquid phase in the drilling fluid waste gas. Correspondingly, when the liquid level sensor reaches a predetermined value, the calcium chloride solution (brine containing calcium chloride) can be pumped into the circulation storage tank 26 or into a water tank (not shown) for temporary storage through the pump body, so as to realize the recycling of waste.

[0079] Preferably, the brine containing calcium chloride can be used to prepare a composite salt drilling fluid or added as brine to an oil-based drilling fluid. Therefore, the present invention utilizes the characteristic that calcium chloride as a desiccant is extremely easy to absorb water, and the formed brine solution is used in-situ for the performance maintenance of the oil-based drilling fluid, so as to further realize the purpose of recycling waste.

[0080] The function of the drying box 41 in the present invention is to remove the liquid phase in the drilling fluid waste gas, thereby extending the service life of the adsorbent in the subsequent adsorption box 42 (introduced below).

[0081] According to the present invention, as Figure 1 and 3As shown, the purification mechanism further includes an adsorption box 42 disposed between the drying box 41 and the induced draft fan 25. Preferably, an adsorbent is disposed in the adsorption box 42, and the adsorbent includes any one of honeycomb activated carbon, molecular sieve, and activated clay.

[0082] Preferably, the drilling fluid waste gas discharged from the drying box 41 enters the adsorption box 42 under the action of the induced draft fan 25. Thus, the drilling fluid waste gas can be fully purified under the action of the adsorbent, so that it can more easily meet the emission standards, thereby further improving the environmental protection performance of the treatment device 100 for drilling fluid waste gas.

[0083] In one embodiment, an exhaust gas concentration monitoring sensor (not shown) is provided on the induced draft fan 25, so as to monitor the quality of the discharged exhaust gas to ensure that the discharged drilling fluid waste gas can meet the emission requirements.

[0084] In one embodiment, a gas external discharge manifold (not shown) is provided at the outlet end of the induced draft fan 25, so as to discharge the qualified gas.

[0085] In one embodiment of the present invention, the treatment device 100 for drilling fluid waste gas further includes a PLC control cabinet (not shown) used in conjunction with the induced draft fan 25. The PLC control cabinet can respectively control the spray box 22, the drying box 23, and the exhaust gas concentration monitoring sensor to achieve the functions of automatic control, automatic detection, and fault warning. Preferably, the controller is a part of the PLC control cabinet.

[0086] According to the second aspect of the present invention, a method for treating drilling fluid waste gas by using the treatment device as described above is provided, including the following steps:

[0087] First, the solid phase is sieved out through the vibrating screen 10 and gas-liquid separation is performed. The separated drilling fluid flows into the circulation storage tank 26, and the separated drilling fluid waste gas enters the spray box 22 through the waste gas collection branch pipe 102 and the waste gas aggregation manifold 30 in sequence under the action of the induced draft fan 25.

[0088] Then, the drilling fluid waste gas enters the drying box 41 after being purified by the spray liquid in the spray box 22; the drilling fluid waste gas enters the adsorption box 42 after being dried by the calcium chloride desiccant in the drying box 41; the drilling fluid waste gas is adsorbed by the adsorbent in the adsorption box 42 and then discharged through the induced draft fan 25.

[0089] The following introduces the purification process of the drilling fluid waste gas in the spray box 22:

[0090] First, the spray liquid in the spray box 22 flows into the water tank after purifying the drilling fluid waste gas;

[0091] Then, the pH value of the sprayed liquid after the reaction is detected at the sampling port. The controller can selectively open the inlet end or the circulating end of the control valve body according to the result of the pH value detection.

[0092] When the detected pH value is less than 7, the inlet end of the valve body is opened through the controller, so as to pump the sprayed liquid after the reaction into the spray box 22 to continue the purification work of the drilling fluid waste gas.

[0093] When the detected pH value is greater than or equal to 7, the circulating end of the valve body is opened through the controller, so as to pump the oil-water mixed emulsion formed after the complete reaction of the sprayed liquid and the drilling fluid waste gas into the circulating storage tank 26, and it plays the roles of a dispersant and a lubricant in the drilling fluid in the circulating storage tank 26, so as to achieve the purpose of waste recycling.

[0094] Compared with the prior art, the advantages of the present invention are as follows:

[0095] Firstly, by integrally arranging the vibrating screen 10, the waste gas collecting branch pipe 102 and the waste gas collecting manifold 30, the present invention not only improves the normal use and relocation operation ability of the vibrating screen 10, but also ensures that the drilling fluid waste gas at the screen mesh 101 position of the vibrating screen 10 can be fully and quickly absorbed, so as to further ensure that the drilling fluid waste gas discharged into the environment meets the emission standards.

[0096] In addition, since both the vibrating screen 10 and the waste gas collecting manifold 30 are installed on the circulating storage tank 26, and the purification mechanism is located below the circulating storage tank 26, not only the total floor area of the whole device is effectively reduced, but also the drilling fluid waste gas can flow smoothly all the way through the reasonable layout, thereby improving the treatment efficiency of the purification mechanism for the drilling fluid waste gas.

[0097] Secondly, in the present invention, the sprayed liquid (such as oleic acid) arranged in the spray box 22 reacts with alkaline gases such as ammonia to generate water and ammonium oleate dissolved in water. At the same time, oleic acid, as an organic acid, can partially absorb the volatile VOCs gas in the oil-based drilling fluid and fix it in the liquid phase. And, since the ammonium oleate aqueous solution in the sprayed liquid can further react to form a relatively stable water-in-oil emulsion after the oleic acid adsorbs the organic gas under the premise that the oleic acid is in excess, and the sprayed liquid will become a milky oil-water mixed emulsion with an alkaline or neutral pH value after the reaction is complete.

[0098] In this way, not only can the drilling fluid waste gas passing through the spray box 22 be well purified to ensure that the subsequent discharged drilling fluid waste gas meets the emission standards, but also the oil-water mixed emulsion formed after the reaction can act as a dispersant and a lubricant in the oil-based drilling fluid and the water-based drilling fluid respectively, thus achieving the purpose of waste recycling and further solving the problems of limited sources of traditional inorganic acid spray agents as hazardous chemicals, limited use at the well site, and difficult treatment of waste liquid after the reaction.

[0099] Thirdly, the present invention utilizes the property that calcium chloride is extremely easy to absorb water as a desiccant, and in-situ uses the brine solution formed after its water absorption for the performance maintenance of the oil-based drilling fluid, so as to further achieve the purpose of waste recycling. In other words, the calcium chloride desiccant in the drying box 41 will form brine containing calcium chloride after absorbing the liquid phase in the drilling fluid waste gas, and can be pumped into the circulation storage tank 26 under the action of the pump body to be added to the oil-based drilling fluid as brine or pumped into the water tank for temporary storage, so as to achieve the recycling of waste.

[0100] The above is only the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can easily make changes or variations within the disclosure scope of the present invention, and such changes or variations should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A treatment device for drilling fluid waste gas, comprising: A vibrating screen (10) for receiving a mixture, and an exhaust gas collection branch pipe (102) is provided on the vibrating screen (10). A purification mechanism connected to the vibrating screen (10), which includes a spray box (22), a drying component, an adsorption box (42) and a draft fan (25) arranged in series below the vibrating screen (10). A circulating storage tank (26) provided between the vibrating screen (10) and the purification mechanism, and An exhaust gas aggregation pipe network (30) provided between the exhaust gas collection branch pipe (102) and the spray box (22). Wherein, the mixture is separated under the action of the vibrating screen (10), the separated drilling fluid flows to the circulating storage tank (26), and the separated drilling fluid exhaust gas flows to the exhaust gas aggregation pipe network (30) through the exhaust gas collection branch pipe (102).

2. The treatment device for drilling fluid waste gas according to claim 1, wherein In the spray box (22), there is a spray liquid for absorbing drilling fluid exhaust gas, the spray liquid is configured as an organic acid, and includes any one of oleic acid, citric acid and malic acid.

3. The treatment device for drilling fluid waste gas according to claim 2, wherein The purification mechanism further includes a water tank provided below the spray box (22) and for receiving the reacted spray liquid, and a valve body configured as a tee structure. Wherein, the valve body includes a valve body inlet end connected to the water tank, a valve body outlet end for pumping the reacted spray liquid into the spray box, and a valve body circulation end for pumping the oil-water mixed emulsion formed by the spray liquid and the drilling fluid exhaust gas into the circulating storage tank.

4. The treatment device for drilling fluid waste gas according to claim 3, wherein A sampling port for detecting the pH value of the spray liquid is provided on the water tank, and the purification mechanism further includes a controller connected to the valve body, and the controller is configured to:[[]] When the pH value detected at the sampling port is less than 7, be able to open the valve body outlet end to pump the spray liquid into the spray box (22). When the pH value detected through the sampling port is greater than or equal to 7, be able to open the valve body circulation end to pump the oil-water mixed emulsion into the circulating storage tank (26).

5. The treatment device for drilling fluid waste gas according to claim 4, wherein The drying component includes a drying box (41), a pump body provided at the outlet of the drying box (41), and a liquid level sensor provided on the drying box (41). Wherein, calcium chloride desiccant for drying drilling fluid exhaust gas is accommodated in the drying box (41), and the pump body is configured to be able to pump the calcium chloride solution into the circulating storage tank (26) when the liquid level sensor reaches a predetermined value.

6. The treatment device for drilling fluid waste gas according to claim 5, wherein An adsorbent is accommodated in the adsorption box (42), and the adsorbent includes any one of honeycomb activated carbon, molecular sieve and activated clay.

7. The treatment device for drilling fluid waste gas according to claim 6, wherein A screen (101) is provided at the bottom of the vibrating screen (10). The treatment device further includes a mud inlet trough (11) for injecting the mixture into the vibrating screen (10), and a diversion trough (12) provided in the vibrating screen (10) and for guiding the drilling fluid to the screen (101).

8. The treatment device for drilling fluid waste gas according to claim 7, wherein The treatment device further includes a gas discharge pipe network connected to the draft fan (25), and an exhaust gas concentration monitoring sensor provided on the draft fan (25).

9. A method for treating drilling fluid waste gas by using the treatment device according to any one of claims 1 to 8, comprising the following steps: S1. The mixture is separated by the vibrating screen (10), and the separated drilling fluid flows into the circulation storage tank (26), and the separated drilling fluid waste gas sequentially passes through the waste gas collection branch pipe (102) and the waste gas summary pipe manifold (30) and enters the spray box (22); S2. The drilling fluid waste gas is purified by the spray liquid in the spray box (22) and then enters the drying box (41); S3. The drilling fluid waste gas is dried by calcium chloride desiccant in the drying box (41) and then enters the adsorption box (42), and is adsorbed by the adsorbent in the adsorption box (42) and then discharged.

10. The method according to claim 9, wherein The purification step S201 is further included in S2. First, the spray liquid in the spray box (22) flows to the water tank (23) after purifying the drilling fluid waste gas. Then, the pH value of the liquid in the water tank is detected through the sampling port. If the pH value is less than 7, the controller needs to open the outlet end of the valve body to pump the spray liquid into the spray box (22); if the pH value is greater than or equal to 7, the controller needs to open the circulation end of the valve body to pump the oil-water mixed emulsion into the circulation storage tank.

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