Method and device for recycling and treating small amount of waste hydrocarbon liquid to micro-positive pressure system

Abstract

The invention relates to the technical field of waste hydrocarbon liquid recycling, in particular to a method and a device for recycling a small amount of waste hydrocarbon liquid to a micro-positive pressure system, and the method comprises the following steps: collecting the waste hydrocarbon liquid into a thermal blow-down tank, and performing fractionation, condensation, oil-water separation, re-fractionation and hydrotreatment on the waste hydrocarbon liquid to realize maximum recycling of resources. The invention provides a method for recycling a small amount of waste hydrocarbon liquid from a micro-positive pressure system, which comprises the following steps: carrying out fractionation, condensation, gravitational separation and hydrogenation reaction on the waste hydrocarbon liquid accumulated to a certain amount, so that gasoline and heavy oil components in the waste hydrocarbon liquid are reasonably treated and recycled. Meanwhile, in the collection process of the small amount of waste hydrocarbon liquid, the small amount of waste hydrocarbon liquid is completely and hermetically recovered into the thermal blow-off tank, the collection process realizes the complete and hermetically recovery of the small amount of waste hydrocarbon liquid, and the waste liquid does not need to be stored on site, so that the source of peculiar smell is cut off from the source, and the field environment is improved.

Description

Technical Field

[0001] The invention relates to the technical field of waste hydrocarbon liquid recovery, in particular to a method and a device for recovering and treating a small amount of waste hydrocarbon liquid into a micro-positive pressure system. Background Art

[0002] In the ethylene plant, when heavy oil is sampled, a small amount of waste hydrocarbon liquid discharged and samples after analysis will be uniformly barreled and placed in the on-site management area, or a small amount of waste hydrocarbon / water mixed liquid will be directly discharged to the floor drain or dumped into the rain drain, flowing to the normal pressure sewage pool by gravity, and entrusted to external treatment after accumulating a certain amount. The on-site hydrocarbon pipeline involves drainage and dredging, equipment maintenance and instrumentation, etc., which will involve the discharge of trace amounts of waste hydrocarbon liquid. Therefore, the waste hydrocarbon liquid generated during on-site sampling, metering, maintenance and production operations cannot be recycled and treated after accumulating a certain amount.

[0003] A small amount of waste hydrocarbon liquid generated by heavy oil sampling is uniformly packed in barrels and placed in the on-site management area. The hydrocarbon barrels are not tightly sealed, and the lighter hydrocarbons in the waste hydrocarbon liquid volatilize to the factory area. In addition, the hydrocarbon barrels are placed on site for a long time, causing a strong odor on site and posing a safety hazard. A small amount of waste hydrocarbon liquid is directly discharged into floor drains and rain drains, which are directly connected to the atmosphere, resulting in a serious odor on site, polluting the environment, posing a safety hazard, and not meeting environmental protection requirements. Therefore, there is no safe way to handle the waste hydrocarbon liquid generated by normal or abnormal disposal on site.

[0004] Since waste hydrocarbon liquid is flammable, volatile, and toxic, it pollutes the environment, affects safety, and consumes resources during the production process of the device. Waste hydrocarbon liquid mainly contains gasoline, heavy oil components, and waste gas. Gasoline is mainly C5 and above components. Gasoline is rich in 75% aromatics (benzene, toluene, and xylene) and styrene and other components, which are important raw materials for downstream deep processing. The main component of heavy oil is aromatics, of which total cyclic aromatics account for nearly 82% and asphaltene accounts for 18%. They are the main raw materials for the production of heavy fuel oil and petroleum naphthalene. Waste gas is mainly light hydrocarbons, such as C4 and components lighter than C4.

[0005] At present, there is no reasonable way to deal with a small amount of waste hydrocarbon liquid, and the resources are not reasonably recycled, resulting in waste of resources and economic losses. Summary of the invention

[0006] The present invention provides a method and device for recovering and processing a small amount of waste hydrocarbon liquid into a micro-positive pressure system, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem of waste of resources caused by the inability to effectively process and recover a small amount of waste hydrocarbon liquid.

[0007] One of the technical solutions of the present invention is achieved by the following measures: A method for recovering a small amount of waste hydrocarbon liquid to a micro-positive pressure system is carried out as follows: S1, the waste hydrocarbon liquid generated by on-site sampling, metering and maintenance is sent to a closed waste hydrocarbon liquid collection tank, and the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank is sent to a slightly positive pressure hot blowdown tank through a hot air flow. The waste hydrocarbon liquid intermittently discharged from the ethylene device is also sent to the hot blowdown tank, the waste hydrocarbon liquid accumulated in the hot blowdown tank is heated, and the waste gas generated is sent to a flare for combustion treatment; S2, sending the heated waste hydrocarbon liquid in the hot blowdown tank to the oil washing tower for fractionation to obtain heavy fuel oil and light component gasoline; S3, directly sending the heavy fuel oil from the bottom of the oil washing tower, and sending the light component gasoline from the top of the oil washing tower to the water washing tower for condensation to obtain an oil-water mixture; S4, the oil-water mixture is sent to the oil-water separation tank through the bottom of the water washing tower for separation, and the crude gasoline and water phase are obtained. The water phase is sent to the subsequent unit for steam reuse; S5, a part of the crude gasoline is returned to the oil washing tower for reflux, and another part of the crude gasoline is sent to the fractionation tower for fractionation to obtain a C8 component product and gasoline with the C8 component removed; S6, the C8 component product is sent out from the bottom of the distillation tower, and the gasoline with the C8 component removed is sent to a hydrogenation unit for hydrogenation reaction to obtain a product rich in aromatic components.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above-mentioned hot gas flow is steam, the hot sewage tank is under a slight positive pressure, the slight positive pressure is 0.002MPaG to 0.003MPaG, and the heating temperature is 130℃ to 180℃.

[0009] The working pressure of the above oil washing tower is 0.04MPaG to 0.05MPaG, and the working temperature is 106℃ to 210℃.

[0010] The working pressure of the above-mentioned water washing tower is 0.03MPaG to 0.04MPaG, and the working temperature is 38℃ to 83℃.

[0011] The above-mentioned distillation tower is under negative pressure, the working pressure is -60KPaG, and the working temperature is 55℃ to 130℃.

[0012] The above-mentioned hydrogenation device includes a first-stage hydrogenation reactor and a second-stage hydrogenation reactor. The reaction pressure of the first-stage hydrogenation reactor is 3.0MPaG and the operating temperature is 60℃ to 120℃. The reaction pressure of the second-stage hydrogenation reactor is 2.8MPaG and the operating temperature is 240℃ to 280℃.

[0013] The second technical solution of the present invention is achieved through the following measures: a device for recovering and treating a small amount of waste hydrocarbon liquid in a micro-positive pressure system, comprising a waste hydrocarbon liquid collection tank, a steam pipeline, a hot sewage tank, an oil washing tower, a water washing tower, an oil-water separation tank, a distillation tower and a hydrogenation device, a first treatment pipeline is fixedly connected between the bottom outlet of the waste hydrocarbon liquid collection tank and the inlet of the hot sewage tank, a steam pipeline is fixedly connected on the first treatment pipeline, an intermittent waste hydrocarbon liquid inlet pipeline is fixedly connected on the first treatment pipeline between the steam pipeline and the hot sewage tank, a waste gas pipeline is fixedly connected to the top outlet of the hot sewage tank, a second treatment pipeline is fixedly connected between the hot sewage tank outlet and the lower inlet of the oil washing tower, a heavy fuel oil delivery pipeline is fixedly connected to the bottom outlet of the oil washing tower, and a third outlet between the top outlet of the oil washing tower and the lower inlet of the water washing tower is fixedly connected to the waste gas pipeline. The fourth processing pipeline is fixedly connected between the bottom outlet of the water washing tower and the inlet of the oil-water separation tank, the fifth processing pipeline is fixedly connected between the side outlet of the oil-water separation tank and the second processing pipeline, the bottom outlet of the oil-water separation tank is fixedly connected with a water phase delivery pipeline, the fifth processing pipeline and the inlet of the fractionation tower are fixedly connected with a sixth processing pipeline, the bottom outlet of the fractionation tower is fixedly connected with a carbon eight component delivery pipeline, the top outlet of the fractionation tower is fixedly connected with the inlet of the hydrogenation unit, the outlet of the hydrogenation unit is fixedly connected with an aromatic component delivery pipeline, a shut-off valve 1 is fixedly installed on the first processing pipeline between the waste hydrocarbon liquid collecting tank and the steam pipeline, a shut-off valve 2 is fixedly installed on the first processing pipeline between the steam pipeline and the intermittent waste hydrocarbon liquid inlet pipeline, and a shower valve is fixedly installed on the steam pipeline.

[0014] The following is a further optimization and / or improvement of the second technical solution of the above invention: A material level detector is fixedly installed on the hot sewage tank, an electric-controlled delivery pump is fixedly installed on the second processing pipeline between the hot sewage tank and the fifth processing pipeline, and an interlock is provided between the material level detector and the electric-controlled delivery pump.

[0015] A temperature detector and a pressure monitor are fixedly installed on the hot sewage tank.

[0016] The above-mentioned hydrogenation device is a hydrogenation reactor.

[0017] The present invention provides a method for recycling a small amount of waste hydrocarbon liquid to a micro-positive pressure system, wherein the waste hydrocarbon liquid accumulated to a certain amount is subjected to a treatment process of fractionation, condensation, gravity separation and hydrogenation reaction, so that the gasoline and heavy oil components in the waste hydrocarbon liquid are reasonably disposed of and recycled. At the same time, the collection process of a small amount of waste hydrocarbon liquid of the present invention is to completely and hermetically recycle a small amount of waste hydrocarbon liquid into a hot sewage tank, and the collection process realizes a small amount of waste hydrocarbon liquid completely and hermetically recycled, and there is no need to store the waste liquid on site, thus cutting off the source of odor from the source, improving the on-site environment, eliminating the potential safety hazards on site, preventing the waste liquid from volatilizing and polluting the environment, and meeting environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 The figure is a schematic diagram of the process flow of the best embodiment of the present invention.

[0019] The codes in the attached drawings are: 1 is a waste hydrocarbon liquid collecting tank, 2 is a steam pipeline, 3 is a hot sewage tank, 4 is an oil washing tower, 5 is a water washing tower, 6 is an oil-water separation tank, 7 is a distillation tower, 8 is a hydrogenation unit, 9 is a first processing pipeline, 10 is an intermittent waste hydrocarbon liquid inlet pipeline, 11 is an exhaust gas pipeline, 12 is a second processing pipeline, 13 is a third processing pipeline, 14 is a heavy fuel oil delivery pipeline, 15 is a temperature detector, 16 is a fourth processing pipeline, 17 is a fifth processing pipeline, 18 is a water phase delivery pipeline, 19 is a sixth processing pipeline, 20 is a C8 component delivery pipeline, 21 is a seventh processing pipeline, 22 is an aromatics-rich component delivery pipeline, 23 is a shut-off valve 1, 24 is a shut-off valve 2, 25 is a shower valve, 26 is a material level detector, 27 is an electronically controlled delivery pump, and 28 is a pressure monitor. DETAILED DESCRIPTION

[0020] The present invention is not limited by the following embodiments, and specific implementation methods can be determined according to the technical scheme of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all known and commonly used chemical reagents and chemicals in the prior art.

[0021] The present invention will be further described below in conjunction with embodiments: Embodiment 1: As attached Figure 1 As shown, the method for recovering and treating a small amount of waste hydrocarbon liquid to a micro-positive pressure system is carried out as follows: S1, the waste hydrocarbon liquid generated by on-site sampling, metering and maintenance is sent to a closed waste hydrocarbon liquid collection tank, and the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank 1 is sent to the slightly positive pressure hot sewage tank 3 through a hot air flow. The waste hydrocarbon liquid intermittently discharged from the ethylene device is also sent to the hot sewage tank 3, and the waste hydrocarbon liquid accumulated in the hot sewage tank 3 is heated, and the generated waste gas is sent to the flare for combustion treatment; S2, sending the heated waste hydrocarbon liquid in the hot blowdown tank 3 to the oil washing tower 4 for fractionation to obtain heavy fuel oil and light component gasoline; S3, directly sending the heavy fuel oil from the bottom of the oil washing tower 4, and sending the light component gasoline from the top of the oil washing tower 4 to the water washing tower 5 for condensation to obtain an oil-water mixture; S4, the oil-water mixture is sent to the oil-water separation tank 6 through the bottom of the water washing tower 5 for separation, and the crude gasoline and water phase are obtained. The water phase is sent to the subsequent unit to generate steam for reuse; S5, a part of the crude gasoline is returned to the oil washing tower 4 for reflux, and another part of the crude gasoline is sent to the fractionation tower 7 for fractionation to obtain a C8 component product and gasoline with the C8 component removed; S6, the C8 component product is sent out from the bottom of the fractionation tower 7, and the gasoline from which the C8 component is removed is sent to the hydrogenation unit 8 for hydrogenation reaction to obtain a product rich in aromatic components.

[0022] Embodiment 2: As attached Figure 1 As shown, as an optimization of the above embodiment, the hot gas flow is steam, the hot sewage tank 3 is at a slightly positive pressure, the slightly positive pressure is 0.002MPaG to 0.003MPaG, and the heating temperature is 130°C to 180°C.

[0023] Embodiment 3: As attached Figure 1 As shown, as an optimization of the above embodiment, the working pressure of the oil washing tower 4 is 0.04 MPaG to 0.05 MPaG, and the working temperature is 106°C to 210°C.

[0024] Embodiment 4: As attached Figure 1 As shown, as an optimization of the above embodiment, the working pressure of the water washing tower 5 is 0.03MPaG to 0.04MPaG, and the working temperature is 38°C to 83°C.

[0025] Embodiment 5: As attached Figure 1 As shown, as an optimization of the above embodiment, the distillation tower 7 is under negative pressure, the working pressure is -60 KPaG, and the working temperature is 55°C to 130°C.

[0026] Embodiment 6: As attached Figure 1 As shown, as an optimization of the above embodiment, the hydrogenation device 8 includes a first-stage hydrogenation reactor and a second-stage hydrogenation reactor. The reaction pressure of the first-stage hydrogenation reactor is 3.0 MPaG, and the operating temperature is 60°C to 120°C. The reaction pressure of the second-stage hydrogenation reactor is 2.8 MPaG, and the operating temperature is 240°C to 280°C.

[0027] Embodiment 7: As attached Figure 1 As shown, the method for recovering and treating a small amount of waste hydrocarbon liquid to a micro-positive pressure system is carried out as follows: S1, send the waste hydrocarbon liquid generated by on-site sampling, metering and maintenance to a sealed waste hydrocarbon liquid collection tank, send the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank 1 to the hot sewage tank 3 (0.002MPaG) through steam, and the waste hydrocarbon liquid intermittently discharged from the ethylene device is also sent to the hot sewage tank 3. When the material level detector 26 detects that the accumulated waste hydrocarbon liquid in the hot sewage tank 3 reaches the limit value, stop collecting the waste hydrocarbon liquid (when the temperature detector 15 detects that the temperature in the hot sewage tank 3 is lower than 90°C, the hot sewage tank 3 starts to heat up, and stops heating after heating to 130°C), start the electronically controlled delivery pump 27, and at the same time, the waste gas generated in the hot sewage tank 3 is sent to the flare for combustion treatment; S2, pumping the heated waste hydrocarbon liquid in the hot blowdown tank 3 to the oil washing tower 4, fractionating at a pressure of 0.04 MPaG, a tower top temperature of 106°C, and a tower bottom temperature of 210°C to obtain heavy fuel oil and light component gasoline; S3, directly sending the heavy fuel oil from the bottom of the oil washing tower 4 to the downstream petroleum naphthalene deep processing device for subsequent treatment, and sending the light component gasoline from the top of the oil washing tower 4 to the water washing tower 5 for condensation to obtain an oil-water mixture; S4, the oil-water mixture is sent to the oil-water separation tank 6 through the bottom of the water washing tower 5, and separated by gravity to obtain crude gasoline and water phase, and the water phase is sent to the subsequent unit to generate steam for reuse; S5, a part of the crude gasoline is returned to the oil washing tower 4 for reflux, and the other part of the crude gasoline is sent to the fractionation tower 7 for fractionation at a pressure of -60 KPaG, a tower top temperature of 55°C, and a tower bottom temperature of 130°C to obtain a C8 component product and gasoline with the C8 component removed; S6, the C8 component product is sent out from the bottom of the distillation tower 7, and the gasoline with the C8 component removed is sent to the hydrogenation unit 8, and a first-stage hydrogenation reaction is carried out at a pressure of 3.0 MPaG and a temperature of 60°C, and a second-stage hydrogenation reaction is carried out at a pressure of 2.8 MPaG and a temperature of 240°C to produce a product rich in more than 75% of aromatic components. Finally, the C8 component product is sent to the subsequent styrene extraction unit for post-processing to obtain a high-value-added styrene product; the product rich in more than 75% of aromatic components is sent to the subsequent aromatic unit for post-processing to obtain benzene, toluene and xylene products.

[0028] Embodiment 8: As attached Figure 1 As shown, the method for recovering and treating a small amount of waste hydrocarbon liquid to a micro-positive pressure system is carried out as follows: S1, the waste hydrocarbon liquid generated by on-site sampling, metering and maintenance is sent to a sealed waste hydrocarbon liquid collection tank, and the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank 1 is sent to the hot sewage tank 3 (0.003MPaG) by steam. The waste hydrocarbon liquid intermittently discharged from the ethylene device is also sent to the hot sewage tank 3. When the material level detector 26 detects that the waste hydrocarbon liquid accumulated in the hot sewage tank 3 reaches the limit value, the collection of waste hydrocarbon liquid is stopped (when the temperature detector 15 detects that the temperature in the hot sewage tank 3 is lower than 90°C, the hot sewage tank 3 starts to heat, and stops heating after the temperature reaches 180°C), the electronically controlled delivery pump 27 is started, and at the same time, the waste gas generated in the hot sewage tank 3 is sent to the flare for combustion treatment; S2, the heated waste hydrocarbon liquid in the hot blowdown tank 3 is pumped to the oil washing tower 4, and fractionated at a pressure of 0.05 MPaG, a tower top temperature of 106°C, and a tower bottom temperature of 210°C to obtain heavy fuel oil and light component gasoline; S3, directly sending the heavy fuel oil from the bottom of the oil washing tower 4 to the downstream petroleum naphthalene deep processing device for subsequent treatment, and sending the light component gasoline from the top of the oil washing tower 4 to the water washing tower 5 for condensation to obtain an oil-water mixture; S4, the oil-water mixture is sent to the oil-water separation tank 6 through the bottom of the water washing tower 5, and separated by gravity to obtain crude gasoline and water phase, and the water phase is sent to the subsequent unit to generate steam for reuse; S5, a part of the crude gasoline is returned to the oil washing tower 4 for reflux, and the other part of the crude gasoline is sent to the fractionation tower 7 for fractionation at a pressure of -60 KPaG, a tower top temperature of 55°C, and a tower bottom temperature of 130°C to obtain a C8 component product and gasoline with the C8 component removed; S6, the C8 component product is sent out from the bottom of the distillation tower 7, and the gasoline with the C8 component removed is sent to the hydrogenation unit 8, and a first-stage hydrogenation reaction is carried out at a pressure of 3.0 MPaG and a temperature of 60°C, and a second-stage hydrogenation reaction is carried out at a pressure of 2.8 MPaG and a temperature of 240°C to produce a product rich in more than 75% of aromatic components. Finally, the C8 component product is sent to the subsequent styrene extraction unit for post-processing to obtain a high-value-added styrene product; the product rich in more than 75% of aromatic components is sent to the subsequent aromatic unit for post-processing to obtain benzene, toluene and xylene products.

[0029] Embodiment 9: As attached Figure 1 As shown, the method for recovering and treating a small amount of waste hydrocarbon liquid to a micro-positive pressure system is carried out as follows: S1, send the waste hydrocarbon liquid generated by on-site sampling, metering and maintenance to a sealed waste hydrocarbon liquid collection tank, send the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank 1 to the hot sewage tank 3 (0.003MPaG) through steam, and the waste hydrocarbon liquid intermittently discharged from the ethylene device is also sent to the hot sewage tank 3. When the material level detector 26 detects that the accumulated waste hydrocarbon liquid in the hot sewage tank 3 reaches the limit value, stop collecting the waste hydrocarbon liquid (when the temperature detector 15 detects that the temperature in the hot sewage tank 3 is lower than 90°C, the hot sewage tank 3 starts to heat, and stops heating after heating to 150°C), start the electronically controlled delivery pump 27, and at the same time, send the waste gas generated in the hot sewage tank 3 to the flare for combustion treatment; S2, pumping the heated waste hydrocarbon liquid in the hot blowdown tank 3 to the oil washing tower 4, fractionating at a pressure of 0.04 MPaG, a tower top temperature of 106°C, and a tower bottom temperature of 210°C to obtain heavy fuel oil and light component gasoline; S3, directly sending the heavy fuel oil from the bottom of the oil washing tower 4 to the downstream petroleum naphthalene deep processing device for subsequent treatment, and sending the light component gasoline from the top of the oil washing tower 4 to the water washing tower 5 for condensation to obtain an oil-water mixture; S4, the oil-water mixture is sent to the oil-water separation tank 6 through the bottom of the water washing tower 5, and separated by gravity to obtain crude gasoline and water phase, and the water phase is sent to the subsequent unit to generate steam for reuse; S5, a part of the crude gasoline is returned to the oil washing tower 4 for reflux, and the other part of the crude gasoline is sent to the fractionation tower 7 for fractionation at a pressure of -60 KPaG, a tower top temperature of 55°C, and a tower bottom temperature of 130°C to obtain a C8 component product and gasoline with the C8 component removed; S6, the C8 component product is sent out from the bottom of the distillation tower 7, and the gasoline with the C8 component removed is sent to the hydrogenation unit 8, and a first-stage hydrogenation reaction is carried out at a pressure of 3.0 MPaG and a temperature of 60°C, and a second-stage hydrogenation reaction is carried out at a pressure of 2.8 MPaG and a temperature of 240°C to produce a product rich in more than 75% of aromatic components. Finally, the C8 component product is sent to the subsequent styrene extraction unit for post-processing to obtain a high-value-added styrene product; the product rich in more than 75% of aromatic components is sent to the subsequent aromatic unit for post-processing to obtain benzene, toluene and xylene products.

[0030] Compared with the prior art, the present invention has the following beneficial effects: Firstly, the present invention provides a method for recovering and processing a small amount of waste hydrocarbon liquid into a micro-positive pressure system, wherein the waste hydrocarbon liquid accumulated to a certain amount is subjected to a treatment process of distillation, condensation, gravity separation and hydrogenation reaction, so that the gasoline and heavy oil components in the waste hydrocarbon liquid can be reasonably disposed of and utilized as resources.

[0031] Secondly, the collection process of a small amount of waste hydrocarbon liquid of the present invention is specifically to send a small amount of waste hydrocarbon liquid generated by on-site sampling, metering, and maintenance to a closed waste hydrocarbon liquid collection tank 11, and send the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank 11 to the hot sewage tank 33 through steam. The entire collection process is to completely and hermetically recover a small amount of waste hydrocarbon liquid to the hot sewage tank 33. This collection process realizes a small amount of waste hydrocarbon liquid completely and hermetically recovers, and there is no need to store the waste liquid on site, which cuts off the source of odor from the source, improves the on-site environment, eliminates safety hazards on site, prevents the waste liquid from volatilizing and polluting the environment, and meets environmental protection requirements.

[0032] Embodiment 10: As attached Figure 1As shown, the device for implementing the method for recovering and treating a small amount of waste hydrocarbon liquid in a micro-positive pressure system comprises a waste hydrocarbon liquid collecting tank 1, a steam pipeline 2, a hot sewage tank 3, an oil washing tower 4, a water washing tower 5, an oil-water separation tank 6, a fractionation tower 7 and a hydrogenation device 8, a first treatment pipeline 9 is fixedly connected between the bottom outlet of the waste hydrocarbon liquid collecting tank 1 and the inlet of the hot sewage tank 3, a steam pipeline 2 is fixedly connected to the first treatment pipeline 9, an intermittent waste hydrocarbon liquid inlet pipeline 10 is fixedly connected to the first treatment pipeline 9 between the steam pipeline 2 and the hot sewage tank 3, a waste gas pipeline 11 is fixedly connected to the top outlet of the hot sewage tank 3, a second treatment pipeline 12 is fixedly connected between the outlet of the hot sewage tank 3 and the lower inlet of the oil washing tower 4, a heavy fuel oil delivery pipeline 14 is fixedly connected to the bottom outlet of the oil washing tower 4, a third treatment pipeline 13 is connected between the top outlet of the oil washing tower 4 and the lower inlet of the water washing tower 5, and a third treatment pipeline 14 is connected between the top outlet of the oil washing tower 4 and the lower inlet of the water washing tower 5. A fourth processing pipeline 16 is fixedly connected to the inlet of the oil-water separation tank 6, a fifth processing pipeline 17 is fixedly connected between the side outlet of the oil-water separation tank 6 and the second processing pipeline 12, a water phase delivery pipeline 18 is fixedly connected to the bottom outlet of the oil-water separation tank 6, a sixth processing pipeline 19 is fixedly connected between the fifth processing pipeline 17 and the inlet of the fractionation tower, a carbon eight component delivery pipeline 20 is fixedly connected to the bottom outlet of the fractionation tower 7, a seventh processing pipeline 21 is fixedly connected between the top outlet of the fractionation tower 7 and the inlet of the hydrogenation unit 8, and an aromatic component-rich delivery pipeline 22 is fixedly connected to the outlet of the hydrogenation unit 8, a shut-off valve 1 23 is fixedly installed on the first processing pipeline 9 between the waste hydrocarbon liquid collecting tank and the steam pipeline 2, a shut-off valve 2 24 is fixedly installed on the first processing pipeline 9 between the steam pipeline 2 and the intermittent waste hydrocarbon liquid inlet pipeline 10, and a drain valve 25 is fixedly installed on the steam pipeline 2.

[0033] Embodiment 11: As attached Figure 1 As shown, as an optimization of the above embodiment, a material level detector 26 is fixedly installed on the hot sewage tank 3, an electric control delivery pump 27 is fixedly installed on the second processing pipeline 12 between the hot sewage tank 3 and the fifth processing pipeline 17, and an interlock is set between the temperature detector 15 and the electric control delivery pump 27. During use, when the material level detector 26 detects that the waste hydrocarbon liquid accumulated in the hot sewage tank 3 reaches a specified upper limit value (higher than 65% of the liquid level height in the hot sewage tank 3), the collection of the waste hydrocarbon liquid is stopped, and at the same time, the interlock electric control delivery pump 27 is started to send the waste hydrocarbon liquid in the hot sewage tank 3 to the oil washing tower 4 for post-processing. When the material level detector 26 detects that the waste hydrocarbon liquid accumulated in the hot sewage tank 3 is lower than the specified lower limit value (lower than 25% of the liquid level height in the hot sewage tank 3), the waste hydrocarbon liquid is collected and at the same time, the interlock electric control delivery pump 27 is turned off. It has the characteristics of high efficiency, convenience, time saving and labor saving.

[0034] Embodiment 12: As attached Figure 1As shown, as an optimization of the above embodiment, a temperature detector 15 and a pressure monitor 28 are fixedly installed on the hot sewage tank 3. During use, when the temperature detector 15 detects that the temperature in the hot sewage tank 3 is lower than 90°C, the heat coil in the hot sewage tank 3 is used for heating, and the pressure monitor 28 monitors the pressure in the hot sewage tank at any time.

[0035] Embodiment 13: As attached Figure 1 As shown, as an optimization of the above embodiment, the hydrogenation device 8 is a hydrogenation reactor.

[0036] Valves are fixedly installed on each pipeline of the device to enable the device to operate normally.

[0037] The present invention implements a device for a method for recovering and treating a small amount of waste hydrocarbon liquid in a micro-positive pressure system, and the implementation process is as follows: First, a small amount of waste hydrocarbon liquid generated by on-site sampling, metering and maintenance is sent to a closed waste hydrocarbon liquid collection tank 1, and the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank 1 is sent to a hot sewage tank 3 by steam.

[0038] The entire collection process realizes a completely closed recovery of a small amount of waste hydrocarbon liquid into the hot sewage tank 3. The specific operation of the collection process is to send a small amount of waste hydrocarbon liquid generated by on-site sampling, metering, and maintenance to the closed waste hydrocarbon liquid collection tank 1, close the cut-off valve 24, open the cut-off valve 1 23, and fill the first processing pipeline 9 with the waste hydrocarbon liquid. Then, close the cut-off valve 1 23, open the cut-off valve 24 and the drainage valve 25, and blow the waste hydrocarbon liquid in the first processing pipeline 9 into the hot sewage tank 3 through steam. The collection process is beneficial in that a small amount of waste hydrocarbon liquid is completely closed and recovered, and there is no need to store the waste liquid on site, which cuts off the source of odor from the source, improves the on-site environment, eliminates safety hazards on site, prevents the waste liquid from volatilizing and polluting the environment, and meets environmental protection requirements.

[0039] Then, a small amount of waste hydrocarbon liquid and waste hydrocarbon liquid intermittently discharged from the ethylene device are also sent to the hot sewage tank 3. When the material level detector 26 detects that the waste hydrocarbon liquid accumulated in the hot sewage tank 3 reaches the specified upper limit, the waste hydrocarbon liquid is stopped from being collected (when the temperature detector 15 detects that the temperature in the hot sewage tank 3 is lower than 90° C., the hot sewage tank 3 is heated by a heat coil), and the interlocking electronically controlled delivery pump 27 is started to send the waste hydrocarbon liquid in the hot sewage tank 3 to the oil washing tower 4 for fractionation to obtain heavy fuel oil and light component gasoline. The heavy fuel oil is directly sent out from the bottom of the oil washing tower 4, and the light component gasoline is sent from the top of the oil washing tower 4 to the water washing tower 5 for condensation to obtain an oil-water mixture. The oil-water mixture is sent to the oil-water separation tank 6 through the bottom of the water washing tower 5 for separation to obtain crude gasoline and water phase. The water phase is sent to the subsequent unit for steam generation and reuse; Finally, a portion of the gasoline is returned to the oil washing tower 4 for reflux, and the other portion of the gasoline is sent to the distillation tower 7 for fractionation to obtain a C8 component product and gasoline with the C8 component removed. The C8 component product is sent out from the bottom of the distillation tower 7, and the gasoline with the C8 component removed is sent to the hydrogenation unit 8 for a two-stage hydrogenation reaction to obtain a product rich in aromatic components more than 75%.

[0040] During the entire implementation process, the gasoline and heavy oil components in the waste hydrocarbon liquid are properly disposed of and utilized as resources.

[0041] In summary, the present invention provides a method for recycling a small amount of waste hydrocarbon liquid to a micro-positive pressure system, and the waste hydrocarbon liquid accumulated to a certain amount is subjected to a treatment process of distillation, condensation, gravity separation and hydrogenation reaction, so that the gasoline and heavy oil components in the waste hydrocarbon liquid are reasonably disposed of and recycled. At the same time, the collection process of a small amount of waste hydrocarbon liquid of the present invention is to completely and hermetically recycle a small amount of waste hydrocarbon liquid into the hot sewage tank 3. This collection process realizes the complete and closed recycling of a small amount of waste hydrocarbon liquid, and there is no need to store the waste liquid on site, which cuts off the source of odor from the source, improves the on-site environment, eliminates the potential safety hazards on site, prevents the waste liquid from volatilizing and polluting the environment, and meets environmental protection requirements.

[0042] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system, Features Proceed as follows: S1, the waste hydrocarbon liquid generated by on-site sampling, metering and maintenance is sent to a closed waste hydrocarbon liquid collection tank, and the waste hydrocarbon liquid in the waste hydrocarbon liquid collection tank is sent to a slightly positive pressure hot blowdown tank through a hot air flow. The waste hydrocarbon liquid intermittently discharged from the ethylene device is also sent to the hot blowdown tank, the waste hydrocarbon liquid accumulated in the hot blowdown tank is heated, and the waste gas generated is sent to a flare for combustion treatment; S2, sending the heated waste hydrocarbon liquid in the hot blowdown tank to the oil washing tower for fractionation to obtain heavy fuel oil and light component gasoline; S3, directly sending the heavy fuel oil from the bottom of the oil washing tower, and sending the light component gasoline from the top of the oil washing tower to the water washing tower for condensation to obtain an oil-water mixture; S4, the oil-water mixture is sent to the oil-water separation tank through the bottom of the water washing tower for separation, and the crude gasoline and water phase are obtained. The water phase is sent to the subsequent unit for steam reuse; S5, a part of the crude gasoline is returned to the oil washing tower for reflux, and another part of the crude gasoline is sent to the fractionation tower for fractionation to obtain a C8 component product and gasoline with the C8 component removed; S6, the C8 component product is sent out from the bottom of the distillation tower, and the gasoline with the C8 component removed is sent to a hydrogenation unit for hydrogenation reaction to obtain a product rich in aromatic components.

2. The method for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 1, Features The hot gas flow is steam, the hot sewage tank is at a slightly positive pressure, the slightly positive pressure is 0.002MPaG to 0.003MPaG, and the heating temperature is 130℃ to 180℃.

3. The method for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 1 or 2, Features The working pressure of the oil washing tower is 0.04MPaG to 0.05MPaG, and the working temperature is 106℃ to 210℃.

4. The method for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 3, Features The working pressure of the water washing tower is 0.03MPaG to 0.04MPaG, and the working temperature is 38℃ to 83℃.

5. The method for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 1, 2 or 4, Features The distillation tower is under negative pressure, the working pressure is -60KPaG, and the working temperature is 55℃ to 130℃.

6. The method for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 5, Features The hydrogenation unit includes a first-stage hydrogenation reactor and a second-stage hydrogenation reactor. The reaction pressure of the first-stage hydrogenation reactor is 3.0MPaG and the operating temperature is 60℃ to 120℃. The reaction pressure of the second-stage hydrogenation reactor is 2.8MPaG and the operating temperature is 240℃ to 280℃.

7. A device for implementing the method for recovering and treating a small amount of waste hydrocarbon liquid to a micro-positive pressure system according to claim 1, 2, 4 or 6, Features The invention comprises a waste hydrocarbon liquid collecting tank, a steam pipeline, a hot sewage tank, an oil washing tower, a water washing tower, an oil-water separation tank, a distillation tower and a hydrogenation device. A first processing pipeline is fixedly connected between the bottom outlet of the waste hydrocarbon liquid collecting tank and the inlet of the hot sewage tank. A steam pipeline is fixedly connected to the first processing pipeline. An intermittent waste hydrocarbon liquid inlet pipeline is fixedly connected to the first processing pipeline between the steam pipeline and the hot sewage tank. A waste gas pipeline is fixedly connected to the top outlet of the hot sewage tank. A second processing pipeline is fixedly connected between the hot sewage tank outlet and the lower inlet of the oil washing tower. A heavy fuel oil delivery pipeline is fixedly connected to the bottom outlet of the oil washing tower. A third processing pipeline is fixedly connected between the top outlet of the oil washing tower and the lower inlet of the water washing tower. A steam pipeline is fixedly connected between the bottom outlet of the water washing tower and the inlet of the oil-water separation tank. A fourth processing pipeline is connected, a fifth processing pipeline is fixedly connected between the side outlet of the oil-water separation tank and the second processing pipeline, a water phase delivery pipeline is fixedly connected to the bottom outlet of the oil-water separation tank, a sixth processing pipeline is fixedly connected between the fifth processing pipeline and the inlet of the distillation tower, a carbon eight component delivery pipeline is fixedly connected to the bottom outlet of the distillation tower, a seventh processing pipeline is fixedly connected between the top outlet of the distillation tower and the inlet of the hydrogenation unit, an aromatic component-rich delivery pipeline is fixedly connected to the outlet of the hydrogenation unit, a shut-off valve 1 is fixedly installed on the first processing pipeline between the waste hydrocarbon liquid collecting tank and the steam pipeline, a shut-off valve 2 is fixedly installed on the first processing pipeline between the steam pipeline and the intermittent waste hydrocarbon liquid inlet pipeline, and a shower valve is fixedly installed on the steam pipeline.

8. The method for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 7, Features A material level detector is fixedly installed on the hot sewage tank, an electric control delivery pump is fixedly installed on the second processing pipeline between the hot sewage tank and the fifth processing pipeline, and an interlock is arranged between the material level detector and the electric control delivery pump.

9. The method and device for recovering and treating a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 8, Features A temperature detector and a pressure monitor are fixedly installed on the hot sewage tank.

10. A method and device for recovering a small amount of waste hydrocarbon liquid into a micro-positive pressure system according to claim 8 or 9, Features The hydrogenation unit is a hydrogenation reactor.

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