Improved device for treating refinery dry gas condensate

Abstract

The utility model provides an improved device for treating refinery dry gas condensate. The improved device comprises a dry gas compressor first-section suction tank, a dry gas compressor second-section suction tank, a quenching water tower and a hydrocarbon stripping tower, an outlet of the main branch pipeline is connected with an inlet pipeline of the hydrocarbon stripping tower; a tower top outlet pipeline of the hydrocarbon stripping tower is connected with a No.2 inlet pipeline of the quenching water tower. Considering the load and the treatment upper limit of the hydrocarbon stripping tower, the original path for returning condensate between sections of the dry gas compressor to the quench water tower is still reserved after the technical improvement is put into use. After improvement, the flow of the condensate between the dry gas compressor sections sent to the quenching water tower and the hydrocarbon stripping tower needs to be adjusted in real time according to the condition of samples between the dry gas compressor sections, quenching water emulsification caused by recovery of the condensate between the dry gas compressor sections with the high pH value is avoided, meanwhile, the running state of the hydrocarbon stripping tower is monitored, and the recovery rate of the condensate between the dry gas compressor sections is increased. If the tray is blocked, the pressure difference rises and the operation is difficult, the in-use hydrocarbon stripping tower needs to be timely cut out for high-pressure cleaning, and the improved device provided by the utility model has the advantages that the process operation is more flexible, and the long-period operation of the device is facilitated, so that the energy consumption of the device is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical industry, in particular to an improved device for treating refinery dry gas condensate. Background Art

[0002] Hengli Petrochemical's ethylene unit utilizes Technip S&W process technology and features 12 cracking furnaces, including nine USC-U-tube cracking furnaces, five of which are equipped with TLX-D heat exchangers. These crackers can accommodate both light liquid feedstocks and C3 / C4 gas feedstocks. Three USC-W-tube cracking furnaces offer high throughput and are suitable for cracking ethane feedstock at high conversion rates. The unit primarily utilizes naphtha, n-butane, and C2 / C3 / C4 recovered from refinery dry gas separation. With a designed annual operating time of 8,000 hours, it produces 1.5 million tons of polymer-grade ethylene and 403,800 tons of polymer-grade propylene annually.

[0003] Hengli Refinery Dry Gas Recovery (ROG) system mainly uses cryogenic separation to separate and purify C2, C3 / C4, C5, fuel gas, etc. in refinery dry gas. Among them, the C2 / C3 / C4 recovered from the refinery dry gas directly enters the cracking furnace as cracking feedstock, deeply integrating the refinery dry gas recovery system with the main ethylene unit to save cracking feedstock and reduce ethylene production costs.

[0004] The quenching system primarily consists of a quenching oil system, a quenching water system, and a dilution steam generation system. The cracked gas passes through the quenching oil system and is then fed to the quenching water system, which then feeds the compression system. The quenching water system plays a crucial role in cooling the cracked gas and recovering low-grade heat energy. As part of the cracked gas pre-fractionation unit, the quenching water system separates the majority of the water and gasoline from the cracked gas, producing the crude cracked gasoline product.

[0005] The cracked gas from the top of the quench oil tower is cooled in the quench water tower and separated from the gasoline and water by the bottom oil / water separator. A portion of the gasoline separated in the bottom of the tower is refluxed, while the remainder enters the gasoline stripper, where it strips the gasoline at the bottom of the quench water tower and the condensed oil returning from the compressor stages. C4 and lighter components in the gasoline are returned from the top of the gasoline stripper to the quench water tower. A portion of the gasoline from the bottom of the gasoline stripper is also refluxed to the top of the quench oil tower, while the remainder is combined with the gasoline from the debutanizer bottom, cooled, and shipped as crude pyrolysis gasoline. A portion of the quench water separated from the quench tower kettle forms a circulation loop. This quench water cycle is used for heat recovery at a specific temperature level. The recovered heat is primarily used in the tower reboiler, feed preheater, and cracker air preheater. The final waste heat is cooled by cooling water in a cooler before being split into two routes and entering the upper and middle sections of the quench tower. The remaining portion passes through a process water filter and a process water coalescer to remove solid coke and entrained hydrocarbons. The remaining portion is then heated by a dilution steam blowdown cooler and a water stripper feed quench oil heat exchanger before entering the process water stripper. The process water in the process water stripper kettle uses low-pressure steam for reboiling, stripping volatile hydrocarbons from the process water and returning it to the quench tower from the top of the process water stripper. The process water in the process water stripper kettle is heated and then sent to the dilution steam generator. The dilution steam generator uses medium-pressure steam as the heat source for dilution steam and as the superheat medium before entering the cracking furnace. The generated dilution steam is sent from the top of the tank to the cracking furnace, and the process wastewater at the bottom of the dilution steam generator tank is sent to the outside after cooling ( Figure 2 ).

[0006] In summary, quench water flows through many devices and has a long process. The quench water quality has a direct impact on the operation of the quench system and can even affect the smooth operation of the entire ethylene unit. In actual operation, due to the uncertainty of the composition of the quench water tower returned by the post-system, the refinery dry gas is particularly affected by the operating status of various related refining and chemical units. Its composition is relatively complex and the load is extremely unstable. When the upstream raw materials or load change, the alkali injection amount of the refinery dry gas recovery system cannot be automatically adjusted online, and the concentration ratio of the alkali solution in the fresh alkali tank cannot be guaranteed to remain unchanged. There will be a certain deviation between the amount of alkali injected during operation and the amount of alkali required under actual operating conditions. This can easily lead to a decrease in the alkali washing effect of the alkali washing tower, unstable tower pressure, and liquid overflow from the tower to the third-stage suction tank. In addition, by cleaning the regulating valves between the refinery dry gas recovery stages and observing the drainage conditions, it was found that the condensate between the refinery dry gas recovery stages contained a large amount of impurities. When condensate containing excessively high alkali concentrations and impurities is returned to the quench water tower from the refinery's dry gas recovery section, the quench water quality typically changes significantly. The pH of the quench water increases, prompting the oil and water to form a stable dispersion. When the two phase droplets collide, they resist coalescence, forming an oil-in-water emulsion, or emulsification of the quench water. Previous studies have shown that pH is the primary factor influencing quench water emulsification, and quench water is highly susceptible to emulsification when the pH reaches 9 or above.

[0007] Emulsification of quench water will deteriorate the heat transfer effect of the quench water heat exchanger. For example, the propylene tower uses quench water as the reboiler heat source. Emulsification of quench water will cause poor reboil heating of the propylene tower, reduced propylene yield, disordered operation of the subsequent system, and increased energy consumption. At the same time, when the emulsified quench water flows through the quench water tower, process water filter, process water coalescer, process water stripping tower and enters the dilution steam generator, it will cause gasoline to carry water, process water to carry oil, dilution steam wastewater oil content to exceed the standard, and dilution steam to carry oil. When oil-laden dilution steam enters the cracking furnace, coking of the cracking furnace tubes accelerates, seriously affecting the cracking furnace's operating cycle. When the cracking furnace is coked, a large amount of air is introduced into the tubes, causing the oil in the dilution steam to burn rapidly at high temperatures, easily damaging the tubes. To mitigate the impact of the oil-laden dilution steam, medium-pressure steam must be directly added to the cracking furnace, which also increases energy consumption. Furthermore, quench water and process water with excessively high pH values ​​can cause alkaline corrosion to the pipelines and equipment they flow through. Especially at higher temperatures, the combined effect of superimposed stress can make pipelines and equipment more susceptible to alkaline embrittlement and damage. Therefore, an excessively high quench water pH value can result in significant material and energy waste, severely impacting the "long-term, full-time, and optimal" operation of the unit, thereby reducing the unit's economic benefits. Utility Model Content

[0008] In view of the above problems, the purpose of this application is to provide an improved device for treating refinery dry gas condensate, which changes the treatment path of the condensate between the refinery dry gas recovery sections to prevent the liquid phase with a higher alkali concentration in the post-system from directly returning to the quenching water tower, causing the pH value of the quenching water to increase, thereby reducing the probability of quenching water emulsification and avoiding the adverse effects of quenching water emulsification on the device as much as possible.

[0009] In order to achieve some or all of the above-mentioned objectives or other objectives, the present application provides the following technical solutions: an improved device for treating refinery dry gas condensate, comprising a first-stage suction tank of a dry gas compressor, a second-stage suction tank of a dry gas compressor, a quenching water tower and a hydrocarbon stripping tower A; the No. 1 inlet pipeline of the first-stage suction tank of the dry gas compressor is connected to the refinery dry gas, the top outlet pipeline of the first-stage suction tank of the dry gas compressor is connected to the inlet pipeline of the second-stage suction tank of the dry gas compressor, the bottom outlet pipeline of the second-stage suction tank of the dry gas compressor is connected to the No. 2 inlet pipeline of the first-stage suction tank of the dry gas compressor, and the tower of the second-stage suction tank of the dry gas compressor is connected to the No. The middle outlet pipeline is connected to the No. 1 inlet pipeline of the quenching water tower, and the bottom outlet pipeline of the first section suction tank of the dry gas compressor is connected to the No. 1 inlet pipeline of the quenching water tower; the bottom outlet pipeline of the first section suction tank of the dry gas compressor is connected to the first branch pipeline inlet, and the first branch pipeline outlet is connected to the main branch pipeline inlet; the middle outlet pipeline of the second section suction tank of the dry gas compressor is connected to the second branch pipeline inlet, and the second branch pipeline outlet is connected to the main branch pipeline inlet; the main branch pipeline outlet is connected to the inlet pipeline of the hydrocarbon stripping tower A, and the top outlet pipeline of the hydrocarbon stripping tower A is connected to the No. 2 inlet pipeline of the quenching water tower.

[0010] Furthermore, it also includes a hydrocarbon stripping tower A feed heater, the outlet pipeline of the hydrocarbon stripping tower A feed heater is connected to the inlet pipeline of the hydrocarbon stripping tower A; two parallel pipelines are set on the inlet pipeline of the hydrocarbon stripping tower A, a main line and a sub-line, the main line is provided with a valve before the hydrocarbon stripping tower A feed flow control valve, a valve of the hydrocarbon stripping tower A feed flow control valve and a valve after the hydrocarbon stripping tower A feed flow control valve, and the sub-line valve of the hydrocarbon stripping tower A feed flow control valve is provided on the sub-line; the outlet of the main branch pipeline is connected between the valve of the hydrocarbon stripping tower A feed flow control valve and the valve after the hydrocarbon stripping tower A feed flow control valve.

[0011] Furthermore, a No. 1 manual valve, a No. 1 one-way valve and a No. 1 drain are provided on the first branch pipeline; a No. 2 manual valve and a No. 2 drain are provided on the second branch pipeline; and a No. 2 one-way valve and a flow meter are provided on the main branch pipeline.

[0012] Furthermore, the bottom outlet pipeline of the first-stage suction tank of the dry gas compressor is provided with a valve before the first-stage suction tank liquid level control valve, a valve after the first-stage suction tank liquid level control valve, and the first branch pipeline is connected between the first-stage suction tank liquid level control valve and the valve after the first-stage suction tank liquid level control valve; the mid-tower outlet pipeline of the second-stage suction tank of the dry gas compressor is provided with a valve before the second-stage suction tank liquid level control valve, a valve after the second-stage suction tank liquid level control valve, and the second branch pipeline is connected between the second-stage suction tank liquid level control valve and the valve after the second-stage suction tank liquid level control valve.

[0013] Furthermore, it also includes a second-stage discharge tank, an alkali washing tower and a third-stage suction tank of a dry gas compressor; the top outlet pipeline of the second-stage suction tank of the dry gas compressor is connected to the inlet pipeline of the second-stage discharge tank, the top outlet pipeline of the second-stage discharge tank is connected to the inlet pipeline of the alkali washing tower, and the top outlet pipeline of the alkali washing tower is connected to the inlet pipeline of the third-stage suction tank of the dry gas compressor; the bottom outlet pipeline of the third-stage suction tank of the dry gas compressor is connected to the No. 2 inlet pipeline of the second-stage suction tank of the dry gas compressor, and the bottom outlet pipeline of the second-stage discharge tank is connected to the No. 1 inlet pipeline of the second-stage suction tank of the dry gas compressor.

[0014] Furthermore, the top outlet pipeline of the first-stage suction tank of the dry gas compressor is provided with a first-stage compressor and a first-stage cooler, and the first-stage compressor is close to the first-stage suction tank of the dry gas compressor; the top outlet pipeline of the second-stage suction tank of the dry gas compressor is provided with a second-stage compressor and a second-stage cooler, and the second-stage compressor is close to the second-stage suction tank of the dry gas compressor.

[0015] Furthermore, the bottom outlet pipeline of the quenching water tower is connected to the inlet pipeline of the quenching water circulation pump; the bottom outlet pipeline of the hydrocarbon stripping tower A is connected to the inlet pipeline of the feed pump of the No. 1 spent alkali oxidation reactor.

[0016] Furthermore, a first valve group is provided on the bottom outlet pipeline of the second-stage suction tank of the dry gas compressor; a second valve group is provided on the bottom outlet pipeline of the third-stage suction tank of the dry gas compressor.

[0017] Furthermore, it also includes a hydrocarbon stripping tower B; the main branch pipeline outlet is connected to the third branch pipeline inlet, the third branch pipeline outlet is connected to the inlet pipeline of the hydrocarbon stripping tower A, and the third branch pipeline is provided with a No. 3 shower and a No. 3 hand valve; the main branch pipeline outlet is also connected to the fourth branch pipeline inlet, the fourth branch pipeline outlet is connected to the inlet pipeline of the hydrocarbon stripping tower B, and the fourth branch pipeline is provided with a No. 4 hand valve; the bottom outlet pipeline of the hydrocarbon stripping tower B is connected to the inlet pipeline of the No. 2 waste alkali oxidation reactor feed pump.

[0018] Furthermore, it also includes a hydrocarbon stripping tower B feed heater, the outlet pipeline of the hydrocarbon stripping tower B feed heater is connected to the inlet pipeline of the hydrocarbon stripping tower B; two parallel pipelines are set on the inlet pipeline of the hydrocarbon stripping tower B, a main line and a sub-line, the main line is provided with a valve before the hydrocarbon stripping tower B feed flow control valve, a valve of the hydrocarbon stripping tower B feed flow control valve and a valve after the hydrocarbon stripping tower B feed flow control valve, and the sub-line valve of the hydrocarbon stripping tower B feed flow control valve is provided on the sub-line; the outlet of the fourth branch pipeline is connected between the valve of the hydrocarbon stripping tower B feed flow control valve and the valve after the hydrocarbon stripping tower B feed flow control valve.

[0019] Compared with the prior art, the beneficial effect of the present invention is that, considering the load and processing upper limit of the hydrocarbon stripping tower, the original path of the dry gas compressor inter-stage condensate returning to the quenching water tower is retained after the technical modification is put into use. After the improvement, it is necessary to pay attention to the real-time adjustment of the flow rate of the dry gas compressor inter-stage condensate sent to the quenching water tower and the hydrocarbon stripping tower according to the dry gas compressor inter-stage sample situation. While avoiding the emulsification of the quenching water caused by the recovery of the dry gas compressor inter-stage condensate with a higher pH value, the operating status of the hydrocarbon stripping tower is monitored. If there is a tower plate blockage, a pressure difference increase, or difficulty in operation, the hydrocarbon stripping tower in use must be cut out in time for high-pressure cleaning. The improved device provided by the present invention makes the process operation more flexible and more conducive to the long-term operation of the device, thereby reducing the energy consumption of the device.

[0020] Based on the existing design process of the device, the process of treating the condensate between the dry gas compressor stages was modified. The condensate between the dry gas compressor stages was returned to the quenching water tower and discharged to the hydrocarbon stripping tower of the waste alkali oxidation system instead.

[0021] The spent caustic oxidation system is primarily used to treat the spent caustic generated during the caustic washing process, which is then discharged to downstream wastewater treatment facilities. The spent caustic liquor contains Na2CO3, Na2S, excess NaOH, butter formed by the polymerization of hydroxyl groups and dienes in the feed gas, and a small amount of dissolved hydrocarbon components. The process sequence of the spent caustic oxidation system consists of a hydrocarbon stripper, an oxidation reactor, and a neutralization system. The hydrocarbon stripper effectively removes organic COD from the spent caustic liquor. It uses BTX solvent (wash oil) to "extract" free hydrocarbons and polymers from the spent caustic liquor, degasses the spent caustic liquor, and flash-evaporates the dissolved hydrocarbon compounds. The stripped hydrocarbon gas is then sent to a quenching water tower for recovery.

[0022] When the interstage condensate from the dry gas compressor contains alkali, its composition is similar to that of the waste alkali liquid, also containing excess NaOH and dissolved hydrocarbons. Changing the treatment process of the interstage condensate from returning it to the quench water tower to the hydrocarbon stripping tower can not only recover the hydrocarbon gas and ensure that the hydrocarbons returned to the quench water tower are relatively pure, but also provide reasonable treatment for the alkaline waste liquid, avoiding the emulsification of the quench water caused by the return of the refinery dry gas recovery interstage condensate with excessively high pH to the water tower.

[0023] Adding branch lines after the regulating valves of the first and second suction tanks of the dry gas compressor returning to the quenching water tower creates a risk of high-pressure leakage during operation. Adding a one-way valve to the branch line of the first suction tank of the dry gas compressor to the hydrocarbon stripping tower prevents the risk of pressure leakage from the second suction tank of the dry gas compressor to the first suction tank of the dry gas compressor when the first and second suction tanks of the dry gas compressor are simultaneously discharged into the hydrocarbon stripping tower. Installing a one-way valve before entering the hydrocarbon stripping tower prevents cross-channeling of materials. Installing a flow meter before entering the hydrocarbon stripping tower facilitates monitoring of the condensate processing volume between dry gas compressor stages, making the material balance accounting of the refinery dry gas recovery system more rigorous. The original design of the refinery dry gas condensate treatment route is retained to avoid the discharge of condensate between dry gas compressor stages into the hydrocarbon stripping tower, which may cause blockage of the hydrocarbon stripping tower trays and affect the operation of waste alkali oxidation. After commissioning, the operating status of the hydrocarbon stripping tower should be monitored in real time. If tray blockage, pressure difference increase, or operation becomes difficult, the hydrocarbon stripping tower should be cut out in time for high-pressure cleaning. If the temperature of the hydrocarbon stripping tower is too low, the condensate between dry gas compressor stages can be sent to the quenching water tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an improved flow chart of the utility model;

[0025] Figure 2 This is a flowchart of the background technology before improvement;

[0026] Figure 3 The pH value change trend of quench water before and after the technical transformation;

[0027] Figure 4 is the flow rate trend of the inter-stage condensate of the dry gas compressor entering the hydrocarbon stripper;

[0028] Figure 5 is the pressure difference trend of hydrocarbon stripper A;

[0029] Figure 6 is the liquid level trend of hydrocarbon stripper A;

[0030] Figure 7 The pressure difference trend of the A / B filter of the spent alkali oxidation feed filter;

[0031] Figure 8 is the pressure difference trend of hydrocarbon stripper B;

[0032] In the figure: 1. First-stage suction tank of dry gas compressor; 2. Second-stage suction tank of dry gas compressor; 3. Quench water tower; 4. Hydrocarbon stripping tower A; 5. Feed heater of hydrocarbon stripping tower A; 6. Hydrocarbon stripping tower B; 7. Feed heater of hydrocarbon stripping tower B; 8. Second-stage discharge tank; 9. Alkali washing tower; 10. Third-stage suction tank of dry gas compressor; 11. Liquid level control valve of first-stage suction tank; 12. Liquid level control valve No. 2 of second-stage suction tank; 13. Feed flow control valve of hydrocarbon stripping tower A; 14. Feed flow control valve of hydrocarbon stripping tower B; 15. Quench water circulation pump; 16. Feed pump of No. 1 waste alkali oxidation reactor; 17. Feed pump of No. 2 waste alkali oxidation reactor; 18. Water stripping tower. DETAILED DESCRIPTION

[0033] In order to make the structure and function of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] See attached Figure 1-2 , an improved device for treating refinery dry gas condensate, comprising a first-stage suction tank 1 of a dry gas compressor, a second-stage suction tank 2 of a dry gas compressor, a quenching water tower 3 and a hydrocarbon stripping tower A4; the No. 1 inlet pipeline of the first-stage suction tank 1 of the dry gas compressor is fed with refinery dry gas, the top outlet pipeline of the first-stage suction tank 1 of the dry gas compressor is connected to the inlet pipeline of the second-stage suction tank of the dry gas compressor, the bottom outlet pipeline of the second-stage suction tank 2 of the dry gas compressor is connected to the No. 2 inlet pipeline of the first-stage suction tank 1 of the dry gas compressor, the mid-tower outlet pipeline of the second-stage suction tank 2 of the dry gas compressor is connected to the No. 1 inlet pipeline of the quenching water tower 3, the The bottom outlet pipeline of the first suction tank 1 is connected to the No. 1 inlet pipeline of the quenching water tower 3; the bottom outlet pipeline of the first suction tank 1 of the dry gas compressor is connected to the first branch pipeline inlet, and the first branch pipeline outlet is connected to the main branch pipeline inlet; the mid-tower outlet pipeline of the second suction tank of the dry gas compressor is connected to the second branch pipeline inlet, and the second branch pipeline outlet is connected to the main branch pipeline inlet; the main branch pipeline outlet is connected to the inlet pipeline of the hydrocarbon stripping tower A4, and the top outlet pipeline of the hydrocarbon stripping tower A4 is connected to the No. 2 inlet pipeline of the quenching water tower 3; the top outlet pipeline of the water stripping tower 18 is connected to the No. 2 inlet pipeline of the quenching water tower 3.

[0035] Furthermore, it also includes a hydrocarbon stripping tower A feed heater 5, the outlet pipeline of the hydrocarbon stripping tower A feed heater 5 is connected to the inlet pipeline of the hydrocarbon stripping tower A4; two parallel pipelines are set on the inlet pipeline of the hydrocarbon stripping tower A4, a main line and a sub-line, the main line is provided with a front valve of the hydrocarbon stripping tower A feed flow control valve 13, a valve of the hydrocarbon stripping tower A feed flow control valve 13 and a valve after the hydrocarbon stripping tower A feed flow control valve 13, and the sub-line valve of the hydrocarbon stripping tower A feed flow control valve 13 is provided on the sub-line; the outlet of the main branch pipeline is connected between the valve of the hydrocarbon stripping tower A feed flow control valve 13 and the valve after the hydrocarbon stripping tower A feed flow control valve 13.

[0036] Furthermore, a No. 1 manual valve, a No. 1 one-way valve and a No. 1 drain are provided on the first branch pipeline; a No. 2 manual valve and a No. 2 drain are provided on the second branch pipeline; and a No. 2 one-way valve and a flow meter are provided on the main branch pipeline.

[0037] Furthermore, the bottom outlet pipeline of the first-stage suction tank 1 of the dry gas compressor is provided with a front valve of the first-stage suction tank liquid level control valve 11, a front valve of the first-stage suction tank liquid level control valve 11 and a rear valve of the first-stage suction tank liquid level control valve 11, and the first branch pipeline is connected between the first-stage suction tank liquid level control valve 11 and the rear valve of the first-stage suction tank liquid level control valve 11; the mid-tower outlet pipeline of the second-stage suction tank of the dry gas compressor is provided with a front valve of the second-stage suction tank liquid level control valve 12, the second-stage suction tank liquid level control valve 12 and the rear valve of the second-stage suction tank liquid level control valve 12, and the second branch pipeline is connected between the second-stage suction tank liquid level control valve 12 and the rear valve of the second-stage suction tank liquid level control valve 12.

[0038] Furthermore, it also includes a second-section discharge tank 8, an alkali washing tower 9 and a third-section suction tank 10 of a dry gas compressor; the top outlet pipeline of the second-section suction tank of the dry gas compressor is connected to the inlet pipeline of the second-section discharge tank 8, the top outlet pipeline of the second-section discharge tank 8 is connected to the inlet pipeline of the alkali washing tower 9, and the top outlet pipeline of the alkali washing tower 9 is connected to the inlet pipeline of the third-section suction tank 10 of the dry gas compressor; the bottom outlet pipeline of the third-section suction tank 10 of the dry gas compressor is connected to the No. 2 inlet pipeline of the second-section suction tank of the dry gas compressor, and the bottom outlet pipeline of the second-section discharge tank 8 is connected to the No. 1 inlet pipeline of the second-section suction tank of the dry gas compressor.

[0039] Furthermore, the top outlet pipeline of the first-stage suction tank 1 of the dry gas compressor is provided with a first-stage compressor and a first-stage cooler, and the first-stage compressor is close to the first-stage suction tank 1 of the dry gas compressor; the top outlet pipeline of the second-stage suction tank of the dry gas compressor is provided with a second-stage compressor and a second-stage cooler, and the second-stage compressor is close to the second-stage suction tank of the dry gas compressor.

[0040] Furthermore, the bottom outlet pipeline of the quenching water tower 3 is connected to the inlet pipeline of the quenching water circulation pump 15; the bottom outlet pipeline of the hydrocarbon stripping tower A4 is connected to the inlet pipeline of the No. 1 waste alkali oxidation reactor feed pump 16; the outlet pipeline of the No. 1 waste alkali oxidation reactor feed pump 16 is connected to the waste alkali oxidation feed filter A.

[0041] Furthermore, a first valve group is provided on the bottom outlet pipeline of the second-stage suction tank of the dry gas compressor; a second valve group is provided on the bottom outlet pipeline of the third-stage suction tank 10 of the dry gas compressor.

[0042] Furthermore, it also includes a hydrocarbon stripping tower B6; the main branch pipeline outlet is connected to the third branch pipeline inlet, the third branch pipeline outlet is connected to the inlet pipeline of the hydrocarbon stripping tower A4, and the third branch pipeline is provided with a No. 3 shower and a No. 3 hand valve; the main branch pipeline outlet is also connected to the fourth branch pipeline inlet, the fourth branch pipeline outlet is connected to the inlet pipeline of the hydrocarbon stripping tower B6, and the fourth branch pipeline is provided with a No. 4 hand valve; the bottom outlet pipeline of the hydrocarbon stripping tower B6 is connected to the inlet pipeline of the No. 2 waste alkali oxidation reactor feed pump 17; the outlet pipeline of the No. 2 waste alkali oxidation reactor feed pump 17 is connected to the waste alkali oxidation feed filter B.

[0043] Furthermore, it also includes a hydrocarbon stripping tower B feed heater 7, the outlet pipeline of the hydrocarbon stripping tower B feed heater 7 is connected to the inlet pipeline of the hydrocarbon stripping tower B6; two parallel pipelines are set on the inlet pipeline of the hydrocarbon stripping tower B6, a main line and a sub-line, the main line is provided with a front valve of the hydrocarbon stripping tower B feed flow control valve 14, a valve of the hydrocarbon stripping tower B feed flow control valve 14 and a valve after the hydrocarbon stripping tower B feed flow control valve 14, and the sub-line valve of the hydrocarbon stripping tower B feed flow control valve 14 is provided on the sub-line; the outlet of the fourth branch pipeline is connected between the valve of the hydrocarbon stripping tower B feed flow control valve 14 and the valve after the hydrocarbon stripping tower B feed flow control valve 14.

[0044] Furthermore, the process of returning the condensate from the compressor inter-stage to the quenching water tower was changed to a hydrocarbon stripping tower for treatment. This not only allows hydrocarbons to be recovered to the water tower for separation through stripping, but also allows the alkali-containing waste liquid to be treated in the waste alkali oxidation unit before being sent out. This also reduces the energy consumed by the waste liquid from the refinery's dry gas recovery inter-stage back to the quenching water tower for circulation, and avoids the emulsification of the quenching water caused by the alkali-containing liquid phase returned from the subsequent system. After optimizing the dry gas waste liquid process, the pH value of the quenching water was significantly reduced to meet the standard ( Figure 3 ), effectively avoid quench water emulsification, optimize the quality of process water and dilution steam, reduce the frequency of cleaning process water filters, ensure the stable operation of the quench unit and the long-term operation of the cracking furnace, and after the technical transformation, the process operation is more flexible, the liquid level of the inter-stage tank is easier to maintain stable, and the alkali corrosion of the post-system is effectively prevented, which is conducive to the long-term stable operation of the unit and reduces the overall energy consumption of the device.

[0045] On April 18, 2024, at 8:52, the technical transformation was put into use and the condensate between the dry gas compressor stages was discharged to the hydrocarbon stripping tower A ( Figure 4 ).

[0046] At 8:59 on April 18, 2024, the pressure difference of hydrocarbon stripping tower A began to rise, and the condensate between the dry gas compressor stages entered hydrocarbon stripping tower A ( Figure 5 ).

[0047] On April 25, 2024, at 1:05, the liquid level of the hydrocarbon stripping tower A suddenly rose, and the waste alkali sent out of the tower bottom was not sufficient ( Figure 6 );

[0048] At 5:00 on April 25, 2024, the waste alkali oxidation feed pump A was switched to B / S operation, and the waste alkali oxidation feed filter A was switched to B operation. The liquid level of the hydrocarbon stripper A dropped and then rose again. According to the cleaning conditions of the on-site pumps and filter screens, it was speculated that the hydrocarbon stripper A disc was clogged and needed to be cut out for high-pressure cleaning ( Figure 7 ).

[0049] At 10:25 on April 26, 2024, the hydrocarbon stripper A switched to the hydrocarbon stripper B. The pressure difference of the hydrocarbon stripper B rose and then remained relatively stable. The condensate between the refinery dry gas recovery section entered the hydrocarbon stripper B ( Figure 8 ).

[0050] Less than a week after entering hydrocarbon stripper A, the refinery's interstage condensate from dry gas recovery sections began to clog its trays. This indicated that the interstage condensate from the dry gas compressor contained a high level of impurities. If this condensate were returned to the water tower, it would likely cause fluctuations in the quenching system's operation. Practical operation has proven that this technical improvement can effectively optimize the quality of process water and dilution steam, ensuring stable operation of the quenching unit and long-term operation of the cracking furnace, thereby reducing the overall energy consumption of the unit.

[0051] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. An improved device for treating refinery dry gas condensate, characterized by: The invention comprises a first-stage suction tank (1) of a dry gas compressor, a second-stage suction tank (2) of a dry gas compressor, a quenching water tower (3) and a hydrocarbon stripping tower A (4); the first inlet pipeline of the first-stage suction tank (1) of the dry gas compressor is connected to the refinery dry gas, the top outlet pipeline of the first-stage suction tank (1) of the dry gas compressor is connected to the inlet pipeline of the second-stage suction tank of the dry gas compressor, the bottom outlet pipeline of the second-stage suction tank of the dry gas compressor is connected to the second inlet pipeline of the first-stage suction tank (1) of the dry gas compressor, the mid-tower outlet pipeline of the second-stage suction tank (2) of the dry gas compressor is connected to the first inlet pipeline of the quenching water tower (3), and the The bottom outlet pipeline of the first section suction tank (1) of the dry gas compressor is connected to the No. 1 inlet pipeline of the quenching water tower (3); the bottom outlet pipeline of the first section suction tank (1) of the dry gas compressor is connected to the first branch pipeline inlet, and the first branch pipeline outlet is connected to the main branch pipeline inlet; the tower outlet pipeline of the second section suction tank (2) of the dry gas compressor is connected to the second branch pipeline inlet, and the second branch pipeline outlet is connected to the main branch pipeline inlet; the main branch pipeline outlet is connected to the inlet pipeline of the hydrocarbon stripping tower A (4), and the top outlet pipeline of the hydrocarbon stripping tower A (4) is connected to the No. 2 inlet pipeline of the quenching water tower (3).

2. The improved device for treating refinery dry gas condensate according to claim 1, characterized in that: It also includes a hydrocarbon stripping tower A feed heater (5), the outlet pipeline of the hydrocarbon stripping tower A feed heater (5) is connected to the inlet pipeline of the hydrocarbon stripping tower A (4); two parallel pipelines are set on the inlet pipeline of the hydrocarbon stripping tower A (4), a main pipeline and a sub-pipeline, the main pipeline is provided with a front valve of the hydrocarbon stripping tower A feed flow control valve (13), a valve of the hydrocarbon stripping tower A feed flow control valve (13) and a valve after the hydrocarbon stripping tower A feed flow control valve (13), and the sub-line valve of the hydrocarbon stripping tower A feed flow control valve (13) is provided on the sub-pipeline; the outlet of the main branch pipeline is connected between the valve of the hydrocarbon stripping tower A feed flow control valve (13) and the valve after the hydrocarbon stripping tower A feed flow control valve (13).

3. The improved device for treating refinery dry gas condensate according to claim 1, characterized in that: A No. 1 manual valve, a No. 1 one-way valve and a No. 1 shower guide are arranged on the first branch pipeline; a No. 2 manual valve and a No. 2 shower guide are arranged on the second branch pipeline; a No. 2 one-way valve and a flow meter are arranged on the main branch pipeline.

4. The improved device for treating refinery dry gas condensate according to claim 1, characterized in that: The tower bottom outlet pipeline of the first-stage suction tank (1) of the dry gas compressor is provided with a front valve of a first-stage suction tank liquid level control valve (11), a first-stage suction tank liquid level control valve (11), and a rear valve of the first-stage suction tank liquid level control valve (11), and the first branch pipeline is connected between the first-stage suction tank liquid level control valve (11) and the rear valve of the first-stage suction tank liquid level control valve (11); the tower mid-outlet pipeline of the second-stage suction tank of the dry gas compressor is provided with a front valve of a second-stage suction tank liquid level control valve (12), a second-stage suction tank liquid level control valve (12), and a rear valve of the second-stage suction tank liquid level control valve (12), and the second branch pipeline is connected between the second-stage suction tank liquid level control valve (12) and the rear valve of the second-stage suction tank liquid level control valve (12).

5. The improved device for treating refinery dry gas condensate according to claim 1, characterized in that: The invention also includes a second-stage discharge tank (8), an alkali washing tower (9) and a third-stage suction tank (10) of a dry gas compressor; the top outlet pipeline of the second-stage suction tank of the dry gas compressor is connected to the inlet pipeline of the second-stage discharge tank (8), the top outlet pipeline of the second-stage discharge tank (8) is connected to the inlet pipeline of the alkali washing tower (9), and the top outlet pipeline of the alkali washing tower (9) is connected to the inlet pipeline of the third-stage suction tank (10) of the dry gas compressor; the bottom outlet pipeline of the third-stage suction tank (10) of the dry gas compressor is connected to the No. 2 inlet pipeline of the second-stage suction tank of the dry gas compressor, and the bottom outlet pipeline of the second-stage discharge tank (8) is connected to the No. 1 inlet pipeline of the second-stage suction tank of the dry gas compressor.

6. The improved device for treating refinery dry gas condensate according to claim 1, characterized in that: The tower top outlet pipeline of the first section suction tank (1) of the dry gas compressor is provided with a first section compressor and a first section cooler, and the first section compressor is close to the first section suction tank (1) of the dry gas compressor; the tower top outlet pipeline of the second section suction tank of the dry gas compressor is provided with a second section compressor and a second section cooler, and the second section compressor is close to the second section suction tank of the dry gas compressor.

7. The improved device for treating refinery dry gas condensate according to claim 1, characterized in that: The bottom outlet pipeline of the quenching water tower (3) is connected to the inlet pipeline of the quenching water circulation pump (15); the bottom outlet pipeline of the hydrocarbon stripping tower A (4) is connected to the inlet pipeline of the feed pump (16) of the No. 1 spent alkali oxidation reactor.

8. The improved device for treating refinery dry gas condensate according to claim 5, characterized in that: A first valve group is provided on the bottom outlet pipeline of the second-stage suction tank of the dry gas compressor; and a second valve group is provided on the bottom outlet pipeline of the third-stage suction tank (10) of the dry gas compressor.

9. The improved device for treating refinery dry gas condensate according to claim 1, characterized in that: It also includes a hydrocarbon stripping tower B (6) and a third branch pipeline; the outlet of the main branch pipeline is connected to the inlet of the third branch pipeline, the outlet of the third branch pipeline is connected to the inlet pipeline of the hydrocarbon stripping tower A (4), and a No. 3 drain and a No. 3 hand valve are provided on the third branch pipeline; the outlet of the main branch pipeline is also connected to the inlet of the fourth branch pipeline, the outlet of the fourth branch pipeline is connected to the inlet pipeline of the hydrocarbon stripping tower B (6), and a No. 4 hand valve is provided on the fourth branch pipeline; the bottom outlet pipeline of the hydrocarbon stripping tower B (6) is connected to the inlet pipeline of the No. 2 spent alkali oxidation reactor feed pump (17).

10. The improved device for treating refinery dry gas condensate according to claim 9, characterized in that: It also includes a hydrocarbon stripping tower B feed heater (7), the outlet pipeline of the hydrocarbon stripping tower B feed heater (7) is connected to the inlet pipeline of the hydrocarbon stripping tower B (6); two parallel pipelines are set on the inlet pipeline of the hydrocarbon stripping tower B (6), a main pipeline and a sub-pipeline, the main pipeline is provided with a hydrocarbon stripping tower B feed flow control valve (14) front valve, a hydrocarbon stripping tower B feed flow control valve (14) valve and a hydrocarbon stripping tower B feed flow control valve (14) rear valve, and the sub-line valve of the hydrocarbon stripping tower B feed flow control valve (14) is provided on the sub-pipeline; the outlet of the fourth branch pipeline is connected between the hydrocarbon stripping tower B feed flow control valve (14) valve and the hydrocarbon stripping tower B feed flow control valve (14) rear valve.

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