Skid-mounted equipment for treating VOCs (Volatile Organic Compounds) in petroleum refining sewage pool

Abstract

The invention discloses skid-mounted equipment for treating VOCs in a petroleum refining sewage pool. The skid-mounted equipment comprises a pretreatment unit, a cooling unit, a solvent absorption unit and an adsorption unit, wherein the adsorption unit comprises a biological catalase device and a zeolite adsorption device which are sequentially connected in series along the flow direction of waste gas. According to the invention, multi-stage dehumidification and oil removal are realized, the oil content and moisture content of waste gas entering a rear-end system are reduced, and the problems of poisoning and blockage of an adsorbent are solved; high-boiling-point components are recovered through condensation, medium-boiling-point components and high-boiling-point components are recovered through solvent absorption, low-boiling-point components are desorbed after being adsorbed and concentrated through zeolite, graded recovery of resources is achieved, and economical efficiency is improved; through cooperative treatment of biological catalase and zeolite adsorption, the biological catalase device is used as pre-pretreatment, macromolecules are converted into micromolecules, and the adsorption load of follow-up zeolite is reduced, so that the whole system can still keep stable emission indexes under the conditions that the concentration of waste gas in a petroleum refining sewage pool is large in fluctuation and the components are complex.

Description

Technical Field

[0001] This invention relates to the field of petroleum refining technology, and in particular to a skid-mounted device for treating VOCs in petroleum refining wastewater ponds. Background Technology

[0002] Oil refining enterprises generate a large amount of oily wastewater during the production process. This wastewater is usually collected and temporarily stored in collection tanks, equalization tanks or oil separators. During the collection, transportation, storage and treatment of wastewater, the volatile organic compounds dissolved and carried in the wastewater will volatilize and disperse, forming high-concentration waste gas.

[0003] Currently, common treatment technologies for VOCs in petroleum refining wastewater ponds include single water spraying combined with activated carbon adsorption, direct combustion, or single bio-trickling filtration. However, in practical engineering applications, these existing technologies have the following significant drawbacks and shortcomings: Wastewater from petroleum refining ponds is characterized by high water vapor content, high oil mist content, and complex composition. Existing treatment equipment often lacks efficient pretreatment, easily leading to rapid adsorbent failure, i.e., "poisoning," which greatly shortens the replacement cycle of adsorption consumables and increases operating costs. Furthermore, common single adsorption technologies have limited adsorption capacity for low-boiling-point, high-volume organic waste gases, and for some complex, high-concentration organic compounds, the adsorption capacity saturates quickly, making it difficult to balance broad-spectrum adsorption with purification efficiency, and posing a risk of secondary pollution. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a skid-mounted device for treating VOCs in petroleum refining wastewater ponds.

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or to describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0006] The present invention adopts the following technical solution: This invention provides a skid-mounted device for VOCs treatment in petroleum refining wastewater ponds, comprising: The pretreatment unit is used to buffer and filter the exhaust gas from the sewage tank to remove dust, oil droplets, and water droplets from the exhaust gas. A cooling unit is located on the exhaust gas output side of the pretreatment unit and is used to condense the moisture and high-boiling-point components in the pretreated exhaust gas through heat exchange. A solvent absorption unit is provided on the exhaust gas output side of the cooling unit and is used to absorb organic components in the cooled exhaust gas using an organic solvent. An adsorption unit is provided on the exhaust gas output side of the solvent absorption unit. The adsorption unit includes a biological catalase device and a zeolite adsorption device connected in series along the exhaust gas flow direction. The bio-catalyst device is loaded with bio-enzyme preparations targeting specific volatile organic compounds, used for bio-enzymatic pretreatment of macromolecular organic compounds in waste gas to decompose components that cause adsorbent poisoning; the zeolite adsorption device is used to adsorb and purify residual low-boiling-point specific components in waste gas after bio-enzymatic pretreatment by passing them through a zeolite honeycomb molecular sieve loaded with active substances.

[0007] Furthermore, the pretreatment unit includes: a gas filter; the gas filter is provided with a first wire mesh demister and a filter spray pipe located below the first wire mesh demister.

[0008] Furthermore, the cooling unit includes: an air-cooled device and a water-cooled device; the heat transfer medium inlets of the water-cooled device and the air-cooled device are connected to the exhaust gas outlet of the gas filter.

[0009] Furthermore, the cooling unit also includes a deep separation tower, the exhaust gas inlet of which is connected to the heat medium outlet of the water cooling device and the air cooling device; the deep separation tower includes a tower body and cooling water pipes, a second wire mesh demister, and a proton exchange membrane arranged from bottom to top within the tower body.

[0010] Furthermore, the solvent absorption unit includes: a liquid pump, a solvent storage tank, a primary absorption tower, and a secondary absorption tower; both the primary and secondary absorption towers are equipped with a gas distribution pipe, a packing layer, and a packing layer spray pipe arranged sequentially from bottom to top; the inlet end of the liquid pump is connected to the solvent storage tank, and the outlet end of the liquid pump is connected to the packing layer spray pipe.

[0011] Furthermore, the bio-catalyst device includes: a housing and, from bottom to top, an exhaust gas distributor, a bio-catalyst layer, and a bio-catalyst layer spray pipe disposed within the housing.

[0012] Furthermore, the aforementioned skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds also includes: an analysis device and a combustion furnace delivery pipeline; the analysis device is connected to the zeolite adsorption device and is used to supply steam or hot air to the zeolite adsorption device; the analysis waste gas outlet of the zeolite adsorption device is connected to the heat medium inlet of the water cooling device and the air cooling device; one end of the combustion furnace delivery pipeline is connected to the analysis waste gas outlet of the zeolite adsorption device, and the other end is connected to the combustion furnace.

[0013] Furthermore, the aforementioned skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds also includes: an induced draft fan and a chimney; the air inlet of the induced draft fan is connected to the zeolite adsorption device, and the air outlet of the induced draft fan is connected to the chimney.

[0014] Furthermore, the aforementioned skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds also includes: a cooling water supply pipeline, a cooling water return pipeline, and a process water supply pipeline; the refrigerant inlet of the water-cooling device and one end of the cooling water pipe in the deep separation tower are connected to the cooling water supply pipeline; the refrigerant outlet of the water-cooling device and the other end of the cooling water pipe in the deep separation tower are connected to the cooling water return pipeline; the biological enzyme layer spray pipeline and the zeolite spray pipeline installed in the zeolite adsorption device are connected to the process water supply pipeline.

[0015] Furthermore, the filter spray pipe within the gas filter is connected to the cooling water return pipe via a water inlet pipe.

[0016] The beneficial effects of this invention are as follows: 1. The pretreatment unit and cooling unit achieve multi-stage dehumidification and oil removal, which significantly reduces the oil and moisture content of the exhaust gas entering the downstream system, solves the problems of adsorbent "poisoning" and clogging, and extends the equipment life.

[0017] 2. This invention adopts a tiered recovery mode that combines condensation, solvent absorption, and adsorption. High-boiling-point components are recovered through condensation, medium- and high-boiling-point components are recovered through solvent absorption, and low-boiling-point components are concentrated and desorbed through zeolite adsorption. The high-concentration waste gas after desorption can be either recycled back into the system or sent to the combustion furnace for treatment, thus realizing the graded recovery of resources and improving economic efficiency. 3. Through the synergistic treatment of bio-catalyst and zeolite adsorption, the bio-catalyst device, as a pretreatment, can convert macromolecules into small molecules, reducing the adsorption load of subsequent zeolite. This allows the entire system to maintain stable emission indicators even when faced with large fluctuations in the concentration and complex composition of exhaust gas from petroleum refining wastewater ponds. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a skid-mounted device for VOCs treatment in a petroleum refining wastewater pond according to the present invention; Figure 2 This is a schematic diagram of the deep separation tower of the present invention; Figure 3 This is a schematic diagram of the primary absorption tower of the present invention; Figure 4 This is a schematic diagram of the biocatalytic enzyme device of the present invention; Figure 5 This is a schematic diagram of the zeolite adsorption device of the present invention. Detailed Implementation

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1-5 As shown in some illustrative embodiments, a skid-mounted device for VOCs treatment in petroleum refining wastewater ponds is provided. This device adopts an integrated skid-mounted design, combining various functional units in the waste gas treatment process to achieve efficient purification and resource recovery of volatile waste gas from wastewater ponds.

[0022] Specifically, it includes: a pretreatment unit 100, a cooling unit 200, a solvent absorption unit 300, an adsorption unit 400, a desorption device 500, a combustion furnace conveying pipeline 600, an induced draft fan 700, a chimney 800, a cooling water supply pipeline 1001, a cooling water return pipeline 1002, a process water supply pipeline 1003, and a water intake pipeline 1004.

[0023] Waste gas from the oil refining wastewater pond first enters the pretreatment unit 100 to remove mechanical impurities and most of the liquid droplets. It then enters the cooling unit 200, where heat exchange lowers the gas temperature and condenses to remove moisture and high-boiling-point organic matter. After cooling and dehumidification, the gas enters the solvent absorption unit 300, where a specific organic solvent absorbs most of the medium- and high-boiling-point organic components. Subsequently, the gas enters the adsorption unit 400, where it first undergoes biodegradation in the biocatalyst device 410, and then enters the zeolite adsorption device 420 for deep adsorption and purification. Finally, the clean gas that meets the standards is discharged through the chimney 800 under the power of the induced draft fan 700.

[0024] After being covered and sealed, the wastewater from the sewage tank and other locations is transported to the pretreatment unit 100 through pipelines. The pretreatment unit 100 is used to buffer and filter the exhaust gas from the sewage tank to remove dust, oil droplets, and water droplets from the exhaust gas.

[0025] The pretreatment unit 100 includes a gas filter 110; a first wire mesh demister 111 and a filter spray pipe 112 located below the first wire mesh demister 111 are disposed within the gas filter 110. After the exhaust gas enters the filter, it first passes through the first wire mesh demister 111, where larger oil droplets and water droplets in the exhaust gas are intercepted by inertial impaction; at the same time, the liquid sprayed from the filter spray pipe 112 washes the gas, further removing dust and fine oil mist, and preventing clogging of subsequent packing materials and molecular sieves.

[0026] The cooling unit 200 is located on the exhaust gas output side of the pretreatment unit 100 and is used to condense the moisture and high-boiling-point components in the pretreated exhaust gas through heat exchange, thereby reducing the load on subsequent treatment units.

[0027] The cooling unit 200 includes: a water cooling device 210, a deep separation tower 220, and an air cooling device 230.

[0028] The heat transfer medium inlets of the water-cooling device 210 and the air-cooling device 230 are connected to the exhaust gas outlet of the gas filter 110, and the gas temperature is initially reduced through heat exchange. The exhaust gas inlet of the deep separation tower 220 is connected to the heat transfer medium outlets of the water-cooling device 210 and the air-cooling device 230. The deep separation tower 220 includes: a tower body 221 and, from bottom to top, a cooling water pipe 222, a second wire mesh demister 223, and a proton exchange membrane 224 arranged within the tower body 221. After the exhaust gas enters the tower body 221, it first undergoes deep cooling through the cooling water pipe 222, allowing water vapor and high-boiling-point organic matter to fully condense. The rising condensate droplets are captured by the second wire mesh demister 223. Finally, the gas passes through the proton exchange membrane 224, which can further intercept fine water mist and polar molecules, ensuring that the gas entering the next unit has an extremely low moisture content, preventing the solvent absorption and adsorption processes from becoming damp and failing.

[0029] The solvent absorption unit 300 is located on the exhaust gas output side of the cooling unit 200 and is used to absorb organic components in the cooled exhaust gas using an organic solvent. Before the project is put into operation, the gas composition must be analyzed, and the appropriate organic solvent for absorption must be selected.

[0030] The solvent absorption unit 300 includes: a liquid pump 310, a solvent storage tank 320, a primary absorption tower 330, and a secondary absorption tower 340.

[0031] Both the primary absorption tower 330 and the secondary absorption tower 340 are equipped with a gas distribution pipe 331, a packing layer 332, and a packing layer spray pipe 333 arranged sequentially from bottom to top; the inlet end of the liquid pump 310 is connected to the solvent storage tank 320, and the outlet end of the liquid pump 310 is connected to the packing layer spray pipe 333.

[0032] During operation, liquid pump 310 extracts and pressurizes a specific organic solvent stored in solvent storage tank 320, and delivers it to the spray pipe 333 of the packing layer. Waste gas enters from the bottom of the tower, is evenly distributed through gas distribution pipe 331, and flows upwards, making full contact with the solvent flowing downwards on the surface of the packing layer 332. Based on the analysis results of the waste gas components before the project was put into operation, a targeted organic solvent was selected to efficiently dissolve the organic components in the waste gas. After two stages of series absorption, most of the organic matter is recovered, and the remaining low-concentration gas enters the adsorption unit.

[0033] The adsorption unit 400 is located on the exhaust gas output side of the solvent absorption unit 300. The adsorption unit 400 includes a biological enzyme device 410 and a zeolite adsorption device 420 connected in series along the exhaust gas flow direction.

[0034] The bio-catalyst device 410 includes a housing 411 and, from bottom to top, a waste gas distributor 412, a bio-catalyst layer 413, and a bio-catalyst layer spray pipe 414 disposed within the housing 411. The bio-catalyst device 410 contains bio-enzyme preparations targeting specific volatile organic compounds, used for bio-enzymatic pretreatment of large molecular organic compounds in the waste gas to decompose components that cause adsorbent poisoning.

[0035] The bio-catalyst layer 413 is loaded with bio-enzyme preparations targeting specific VOCs components. When the residual waste gas after solvent absorption passes through, the bio-enzymes enzymatically decompose the large molecules, recalcitrant organic matter, or organic matter that easily leads to adsorbent poisoning in the waste gas into small molecules, harmless or easily adsorbed substances.

[0036] The zeolite adsorption device 420 is used to adsorb and purify residual low-boiling-point components in waste gas after bio-enzymatic hydrolysis pretreatment by passing the zeolite honeycomb molecular sieve loaded with active materials. After bio-enzymatic pretreatment, the waste gas enters the zeolite adsorption device 420. The zeolite honeycomb molecular sieve utilizes its huge specific surface area to specifically physical adsorb the residual low-boiling-point components, ensuring that the exhaust gas indicators meet national emission standards.

[0037] The desorption device 500 is connected to the zeolite adsorption device 420 and is used to supply steam or hot air to the zeolite adsorption device 420. When the zeolite molecular sieve adsorption reaches saturation, the desorption device 500 is started and a hot medium is introduced to desorb the organic matter adsorbed on the zeolite, so that the zeolite can be regenerated for reuse.

[0038] The zeolite adsorption unit 420 has two branches at its exhaust gas outlet: one branch connects to the heat medium inlet of the water-cooling unit 210 and the air-cooling unit 230, and the other connects to the combustion furnace via the combustion furnace delivery pipeline 600. The high-concentration exhaust gas generated during desorption can either be returned to the front end of the cooling unit 200 for re-entry into the system for condensation, absorption, and adsorption recycling, or it can be directly transported to the existing combustion furnace in the plant for incineration, achieving flexible energy recovery and disposal. The recycling of the desorbed gas reduces fuel consumption from direct combustion.

[0039] The air inlet of the induced draft fan 700 is connected to the zeolite adsorption device 420, and the air outlet of the induced draft fan 700 is connected to the chimney 800. Finally, the purified gas is discharged into the atmosphere through the induced draft fan 700, and the power system of the entire system is provided by the induced draft fan 700.

[0040] The refrigerant inlet of the water-cooling device 210 and one end of the cooling water pipe 222 of the deep separation tower 220 are connected to the cooling water supply pipe 1001. The refrigerant outlet of the water-cooling device 210 and the other end of the cooling water pipe 222 of the deep separation tower 220 are connected to the cooling water return pipe 1002. The biological enzyme layer spray pipe 414 and the zeolite spray pipe 421 installed in the zeolite adsorption device 420 are connected to the process water supply pipe 1003.

[0041] The cooling water supply pipe 1001 is connected to the refrigerant inlet of the water cooling device 210 and one end of the cooling water pipe 222 of the deep separation tower 220 respectively; the cooling water return pipe 1002 is connected to the refrigerant outlet of the water cooling device 210 and the other end of the cooling water pipe 222 respectively, forming a circulating cooling loop.

[0042] The process water supply pipe 1003 is connected to the biological enzyme layer spray pipe 414 and the zeolite spray pipe 421 respectively, to provide the humidity required for the survival of biological enzymes and to clean the zeolite regularly.

[0043] The filter spray pipe 112 inside the gas filter 110 is connected to the cooling water return pipe 1002 via the water inlet pipe 1004. The return water after system use can be used as pre-treated spray water, realizing the cascade utilization of water resources and reducing the consumption of fresh water.

[0044] Traditional adsorption equipment directly treats oily and watery waste gas, making it prone to failure. This invention solves the problems of adsorbent poisoning and clogging. Through multi-stage dehumidification and oil removal via the pretreatment unit 100 and the deep separation tower 220, the oil and moisture content of the waste gas entering the downstream system is significantly reduced. In particular, the inclusion of the bio-catalyst device 410 pre-decomposes large organic molecules and specific components that can cause adsorbent poisoning, effectively protecting the downstream zeolite molecular sieve, thereby extending the service life of the adsorbent material and reducing replacement costs.

[0045] This invention employs a tiered recovery model combining condensation, solvent absorption, and adsorption. High-boiling-point components are recovered through condensation, medium- and high-boiling-point components are recovered through solvent absorption, and low-boiling-point components are concentrated and desorbed via zeolite adsorption. The high-concentration waste gas after desorption can either be recycled back into the system or sent to a combustion furnace for treatment, maximizing the recovery of valuable organic matter.

[0046] By combining bio-catalysts with zeolite adsorption, not only is the efficiency of physical adsorption utilized, but also the ability of biodegradation to treat recalcitrant substances. The bio-catalyst device, acting as a pretreatment step before the adsorption unit, converts macromolecules into smaller molecules, reducing the adsorption load on subsequent zeolite. This allows the entire system to maintain stable emission standards even when faced with large fluctuations in the concentration and complex composition of waste gas from petroleum refining wastewater ponds.

[0047] This equipment adopts a skid-mounted design, which saves space. Moreover, the solvent absorption unit 300 can select specific organic solvents based on the analysis results of the waste gas composition, making the equipment widely adaptable to waste gas from petroleum refining wastewater ponds under different operating conditions.

[0048] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds, characterized in that, include: The pretreatment unit is used to buffer and filter the exhaust gas from the sewage tank to remove dust, oil droplets, and water droplets from the exhaust gas. A cooling unit is located on the exhaust gas output side of the pretreatment unit and is used to condense the moisture and high-boiling-point components in the pretreated exhaust gas through heat exchange. A solvent absorption unit is provided on the exhaust gas output side of the cooling unit and is used to absorb organic components in the cooled exhaust gas using an organic solvent. An adsorption unit is provided on the exhaust gas output side of the solvent absorption unit. The adsorption unit includes a biological catalase device and a zeolite adsorption device connected in series along the exhaust gas flow direction. The bio-catalyst device is loaded with bio-enzyme preparations targeting specific volatile organic compounds, used for bio-enzymatic pretreatment of macromolecular organic compounds in waste gas to decompose components that cause adsorbent poisoning; the zeolite adsorption device is used to adsorb and purify residual low-boiling-point specific components in waste gas after bio-enzymatic pretreatment by passing them through a zeolite honeycomb molecular sieve loaded with active substances.

2. The skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 1, characterized in that, The pretreatment unit includes: a gas filter; the gas filter is provided with a first wire mesh demister and a filter spray pipe located below the first wire mesh demister.

3. The skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 2, characterized in that, The cooling unit includes an air-cooled device and a water-cooled device; the heat transfer medium inlets of the water-cooled device and the air-cooled device are connected to the exhaust gas outlet of the gas filter.

4. The skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 3, characterized in that, The cooling unit further includes a deep separation tower, the exhaust gas inlet of which is connected to the heat medium outlet of the water cooling device and the air cooling device. The deep separation tower includes: a tower body and cooling water pipes, a second wire mesh demister, and a proton exchange membrane arranged from bottom to top within the tower body.

5. The skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 4, characterized in that, The solvent absorption unit includes a liquid pump, a solvent storage tank, a primary absorption tower, and a secondary absorption tower. The primary and secondary absorption towers are each equipped with a gas distribution pipe, a packing layer, and a packing layer spray pipe arranged sequentially from bottom to top. The inlet of the liquid pump is connected to the solvent storage tank, and the outlet of the liquid pump is connected to the packing layer spray pipe.

6. The skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 5, characterized in that, The bio-catalyst device includes: a shell and, from bottom to top, an exhaust gas distributor, a bio-catalyst layer, and a bio-catalyst layer spray pipe disposed within the shell.

7. The skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 6, characterized in that, Also includes: Analysis device and combustion furnace delivery pipeline; The analysis device is connected to the zeolite adsorption device and is used to supply steam or hot air to the zeolite adsorption device. The analysis waste gas outlet of the zeolite adsorption device is connected to the heat medium inlet of the water cooling device and the air cooling device. One end of the combustion furnace conveying pipeline is connected to the desorption exhaust gas outlet of the zeolite adsorption device, and the other end is connected to the combustion furnace.

8. The skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 7, characterized in that, Also includes: The induced draft fan and the chimney; the air inlet of the induced draft fan is connected to the zeolite adsorption device, and the air outlet of the induced draft fan is connected to the chimney.

9. A skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 8, characterized in that, Also includes: Cooling water supply pipelines, cooling water return pipelines, and process water supply pipelines; The refrigerant inlet of the water-cooling device and one end of the cooling water pipe in the deep separation tower are connected to the cooling water supply pipe. The refrigerant outlet of the water-cooling device and the other end of the cooling water pipe in the deep separation tower are connected to the cooling water return pipe. The biological catalyst layer spray pipe and the zeolite spray pipe installed in the zeolite adsorption device are connected to the process water supply pipe.

10. A skid-mounted equipment for VOCs treatment in petroleum refining wastewater ponds according to claim 9, characterized in that, The filter spray pipe inside the gas filter is connected to the cooling water return pipe via a water inlet pipe.

Images