An oil circuit system and operation method thereof applied to petrochemical background heat pump process

Abstract

The present invention relates to the technical field of heat pump systems, and in particular to an oil circuit system and an operation method thereof applied to a petrochemical background heat pump process, wherein the oil circuit system comprises a tower top condenser evaporator, a gas-liquid separator and a tower top condenser evaporator are connected by a pipeline; a heating coil is arranged inside the gas-liquid separator, an oil separator and a heating coil are connected by an oil circuit 1, a heating coil and an oil pump are connected by an oil circuit 2, an oil pump and a compressor are connected by an oil circuit 3, and a compressor and an oil separator are connected by a pipeline; an oil circuit 1 is connected to an oil return plate heat exchanger by an oil circuit 4, and the oil return plate heat exchanger is connected to an oil circuit 2 by an oil circuit 5; the tower top condenser evaporator is connected to an oil return plate heat exchanger by an oil return pipe, an oil return solenoid valve and an oil return regulating valve are arranged on the oil return pipe, and a heating oil regulating valve is arranged on the oil circuit 4; the oil return plate heat exchanger and a compressor are connected by an oil circuit 6, and an oil return temperature sensor is arranged on the oil circuit 6. The present invention utilizes waste heat of high-temperature lubricating oil to improve efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and in particular to an oil circuit system and an operating method thereof applied to a petrochemical background heat pump process. Background Art

[0002] The basic process of heat pump distillation is: using Freon-like working fluid as the compressor circulation medium, evaporating in the tower top condenser evaporator and condensing in the tower bottom reboiler, recovering the condensation heat of the tower top gas, and then inputting it into the tower bottom for heating after being lifted by the oil-injected twin-screw compressor unit to achieve energy-saving effect.

[0003] As the unit runs, the lubricating oil in the oil separator of the compressor unit will be brought into the evaporator by the exhaust gas, affecting the heat exchange. It is necessary to rely on the oil return pipeline to recover the lubricating oil in the evaporator to the compressor suction port and then enter the oil separator.

[0004] The heat pump process of petrochemical projects has the following characteristics:

[0005] 1. In terms of compressor unit operating parameters, the working fluid properties of the heat pump distillation compressor unit have the characteristics of low exhaust superheat. The compressor inlet cannot carry liquid working fluid, and the evaporator recovers an oil-liquid mixture, and the proportion of liquid working fluid exceeds 80%. The working fluid condensate must be heated and evaporated before entering the compressor;

[0006] 2. In terms of on-site installation, the heat pump distillation unit occupies a large area and involves many equipment. The evaporator, reboiler, liquid receiver, etc. are generally on the second or third floor platform, with a height difference of more than 20 meters from the compressor and a horizontal distance of more than 50 meters;

[0007] 3. In terms of oil return power, since the evaporator of the heat pump distillation unit is higher than the compressor unit, the oil-liquid mixture in the evaporator can flow back to the compressor suction port by gravity, and no additional power is required;

[0008] 4. In terms of the air intake pipe, the pipe is long and higher than the compressor, and the condensed liquid of the working fluid will flow toward the compressor. It is necessary to set up a gas-liquid separator at the compressor inlet to collect it and evaporate it by electric heating.

[0009] The traditional ejector oil return system relies on the high-pressure and high-temperature exhaust gas of the compressor as the power. The ejector pump reduces the pressure and carries the oil-liquid mixture recovered by the evaporator into the compressor for suction. In order to reduce the condensate content of the working fluid entering the compressor, the sensible heat of the ejector gas is needed to vaporize the liquid, resulting in a significant increase in the amount of ejector gas, which is equivalent to a large-flow bypass pipeline for the compressor, and the energy efficiency of the unit is reduced. Summary of the invention

[0010] In view of the deficiencies in the prior art, the present invention provides an oil circuit system and an operating method thereof for use in a petrochemical background heat pump process.

[0011] The technical solution of the present invention to solve the above technical problems is as follows:

[0012] The first object of the present invention is to provide an oil circuit system applied to a petrochemical background heat pump process, comprising a tower top condenser evaporator and a compressor unit, wherein the tower top condenser evaporator and the compressor unit are connected by a pipeline; an oil return pipe is arranged between the tower top condenser evaporator and the compressor unit, and the compressor unit comprises an oil separator, a compressor, a gas-liquid separator, a heating coil, an oil pump, and an oil return plate heat exchanger, wherein the gas-liquid separator and the tower top condenser evaporator are connected by a pipeline, and the gas-liquid separator and the compressor are connected by a pipeline; the heating coil is arranged inside the gas-liquid separator, and the oil separator and the heating coil are connected by a pipeline. The heating coil and the oil pump are connected through oil circuit one, the oil pump and the compressor are connected through oil circuit three, and the compressor and the oil separator are connected through a pipeline; the oil circuit one is connected to the return oil plate heat exchanger through oil circuit four, and the return oil plate heat exchanger is connected to the oil circuit two through oil circuit five; the tower top condenser evaporator is connected to the return oil plate heat exchanger through an oil return pipe, and an oil return solenoid valve and an oil return regulating valve are provided on the oil return pipe, and a heating oil regulating valve is provided on the oil circuit four; the return oil plate heat exchanger and the compressor are connected through oil circuit six, and an oil return temperature sensor is provided on the oil circuit six.

[0013] By adopting the above technical scheme, in view of the fact that petrochemical projects do not require power, the present invention uses the hot oil in the oil separator of the compressor unit as the heat source for heating the oil-liquid mixture in the oil return pipeline and the condensate in the gas-liquid separator; the pipeline is simple, the system device is compactly installed, and the operation is convenient; the waste heat of high-temperature lubricating oil is utilized instead of the sensible heat or electrical energy of high-pressure gas, thereby avoiding the waste of sensible heat of high-pressure gas and improving efficiency.

[0014] Furthermore, the compressor unit also includes an oil filter, and the oil filter is arranged on the second oil circuit.

[0015] By adopting the above technical solution, the oil filter can filter the oil entering the oil pump.

[0016] Furthermore, the oil circuit five is located between the oil filter and the oil return plate heat exchanger.

[0017] By adopting the above technical solution, the oil filter can filter the oil in the oil circuit five.

[0018] Furthermore, the oil circuit four is connected to the oil circuit two through the oil circuit seven, and the oil circuit seven is located between the oil filter and the oil circuit four.

[0019] By adopting the above technical solution, the oil filter can filter the oil in the oil circuit seven.

[0020] Furthermore, a water-cooled oil cooler is provided on the oil circuit seven.

[0021] By adopting the above technical solution, circulating cooling water is used to cool the lubricating oil to ensure that the temperature of oil circuit three is less than 70°C.

[0022] Furthermore, the oil circuit seven is located between the heating oil regulating valve and the oil circuit one.

[0023] Furthermore, the oil return solenoid valve is located on a side of the oil return regulating valve away from the oil return plate heat exchanger.

[0024] Furthermore, a coil oil regulating valve is provided on the oil circuit 1.

[0025] By adopting the above technical solution, no matter starting or stopping the machine, the coil oil regulating valve can be fully opened without any operation, and there will always be high-temperature oil in the heating coil.

[0026] Furthermore, the exhaust gas of the oil separator is sent to a reboiler.

[0027] The second object of the present invention is to provide an operating method of the oil circuit system applied to the petrochemical background heat pump process as described above, comprising the following steps:

[0028] When the oil level height of the oil separator in the compressor unit drops to the oil return height for the first time, oil return is required, the heating oil regulating valve is fully opened, the return oil regulating valve is closed, and the return oil solenoid valve is opened. At this time, the return oil temperature sensor has a temperature close to the ambient temperature because there is no oil-liquid mixture (oil and liquid working fluid) flowing in the pipeline; slowly open the return oil regulating valve, turn the handwheel half a circle each time, and observe the value of the return oil temperature sensor; just after opening half a circle, as the heated oil flows in the pipeline where the return oil temperature sensor is located, the temperature begins to rise and approaches the temperature of the high-temperature oil of the heat source in the oil separator; as the opening of the return oil regulating valve increases, the liquid working fluid in the pipeline increases, and the return oil temperature sensor value first approaches the hot oil temperature in the oil separator and then decreases; when it drops to 10°C higher than the compressor suction temperature, fix the opening position of the return oil regulating valve and do not adjust it anymore. This opening is the maximum oil return capacity of the oil system;

[0029] If such a large amount of oil return is not needed, that is, the oil return amount needs to be reduced, the oil return regulating valve can be turned down; the standard for judging whether the oil return amount is sufficient is that the oil level height of the oil separator can be seen to rise significantly 4 hours after the start of oil return. Among them, the oil return time needs to be determined according to the specific size of the equipment oil separator;

[0030] After the oil return is completed, close the oil return solenoid valve and keep other valves unchanged. If oil return is needed later, only the oil return solenoid valve needs to be opened and closed.

[0031] In summary, compared with the prior art, the above technical solution has the following beneficial effects:

[0032] (1) Using the high-temperature lubricating oil of the compressor unit as the heat source, compared with the traditional induced return oil which uses the high-temperature and high-pressure compressor exhaust as the heat source, it eliminates the waste of high-temperature and high-pressure exhaust in this way and improves energy efficiency; the heat of high-temperature and high-pressure exhaust is useful heat for the reboiler at the end of the system, while the heat of the high-temperature lubricating oil is useless heat that must be taken away by the circulating cooling water. Therefore, the waste heat that should have been taken away by the circulating cooling water is utilized to improve efficiency;

[0033] (2) Using the compressor unit's own high-temperature oil, the oil return device can be directly installed in the compressor unit skid, that is, the heat source is directly inside the compressor unit skid and directly installed next to the compressor. The heat source is close, the pipeline is short, and the operation is simple. Considering the factors of site, dispatched personnel, pipelines and insulation consumables, transportation, etc., the cost of direct installation by the equipment supplier in the production workshop is much lower than the cost of on-site engineering installation.

[0034] (3) Using high-temperature hot oil as the heat source reduces power consumption compared to the traditional method of heating the condensate in the evaporating gas with electric energy;

[0035] (4) The return oil heating device has a simple structure, is easy to debug, and takes up little space for installation. The entire system only includes an oil return plate heat exchanger, an oil return temperature sensor, an automatic control valve oil return solenoid valve, and several manual regulating valves, all of which occupy no more than 500mm of space. It is directly mounted on the compressor unit, eliminating the workload of on-site engineering. When debugging, there is only one observation object - the return oil temperature sensor, and one adjustment object - the return oil regulating valve, so there is no need to run back and forth between multiple operating positions. The traditional induced oil return requires an additional electric switch valve for high-temperature and high-pressure gas, which must be closed when there is no oil return to stop the consumption of high-pressure gas and prevent high-pressure gas from entering the low-pressure side container and causing the safety valve to trip due to overpressure.

[0036] (5) The valve coil oil regulating valve and heating oil regulating valve of the high-temperature oil as the heat source can be kept open normally, regardless of whether the oil is to be returned or whether the compressor unit is turned on. When the oil return is not required, the lubricating oil in this line enters the main oil pump like the main lubricating oil, and does not affect the oil circulation of the compressor unit; when the compressor unit stops, the main oil pump stops, the flow of the main oil line stops, there is no pressure difference, the lubricating oil in this line has no power, and the flow stops naturally. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the structural connection of the present invention;

[0038] Figure 2 It is a schematic diagram of the structural connection of the compressor unit in the present invention.

[0039] Explanation of the reference numerals in the accompanying drawings: 1. Tower top condenser evaporator; 2. Oil return pipe; 3. Compressor unit; 4. Oil separator; 5. Compressor; 6. Gas-liquid separator; 7. Heating coil; 8. Coil oil regulating valve; 9. Water-cooled oil cooler; 10. Oil filter; 11. Oil pump; 12. Heating oil regulating valve; 13. Return oil plate heat exchanger; 14. Return oil solenoid valve; 15. Return oil regulating valve; 16. Return oil temperature sensor; 17. Reboiler; 18. Distillation tower; 19. Reflux tank; 20. Liquid storage tank; 100. Oil circuit one; 200. Oil circuit two; 300. Oil circuit three; 400. Oil circuit four; 500. Oil circuit five; 600. Oil circuit six; 700. Oil circuit seven DETAILED DESCRIPTION

[0040] The following is combined with Figure 1-2 The principles and features of the present invention are described, and the examples given are only used to explain the present invention, rather than to limit the scope of the present invention.

[0041] The embodiment of the present invention discloses an oil circuit system applied to a petrochemical background heat pump process.

[0042] Reference Figure 1 and Figure 2 An oil circuit system applied to a petrochemical background heat pump process includes a tower top condenser evaporator 1 and a compressor unit 3, wherein the tower top condenser evaporator 1 and the compressor unit 3 are connected by a pipeline, and an oil return pipe 2 is installed between the tower top condenser evaporator 1 and the compressor unit 3.

[0043] The tower top condenser evaporator 1 is connected to a distillation tower 18 and a reflux tank 19 through pipelines, respectively. The tower top of the distillation tower 18 is connected to the inlet of the tower top condenser evaporator 1, and the reflux tank 19 is connected to the distillation tower 18 through pipelines. The distillation feed 1 and the distillation feed 2 are alkane liquids of different components. After entering the distillation tower 18, they fall and mix, and transfer mass and heat with the rising hot gas in the bottom of the distillation tower 18. The light component in the liquid is first vaporized and then rises with the rising gas until it is extracted from the top of the distillation tower 18. The components with intermediate specific gravity are extracted at the middle height of the distillation tower 18, and the heavy components are not completely vaporized and continue to fall to the bottom of the distillation tower 18 before being extracted.

[0044] The exhaust gas of the compressor unit 3 goes to the reboiler 17 through a pipeline. The reboiler 17 is connected to the distillation tower 18 through inlet and outlet pipelines respectively. The reboiler 17 is connected to the inlet of the liquid reservoir 20 through a pipeline, and the outlet of the liquid reservoir 20 is connected to the top condenser evaporator 1 through a pipeline. The gas at the top of the distillation tower 18 enters the top condenser evaporator 1 to condense and liquefy, and the liquid enters the reflux tank 19. Most of the liquid in the reflux tank 19 flows back to the distillation tower 18, and a small part is extracted as a product. The working fluid liquid in the top condenser evaporator 1 absorbs the condensation heat and then vaporizes. It enters the compressor unit 3 for pressurization and then enters the reboiler 17 for condensation and heat release. The condensate enters the liquid reservoir 20, and then returns to the top condenser evaporator 1 for recirculation.

[0045] The compressor unit 3 includes an oil separator 4, a compressor 5, a gas-liquid separator 6, a heating coil 7, an oil pump 11, and an oil return plate heat exchanger 13. The gas-liquid separator 6 is connected to the top condenser evaporator 1 through a pipeline, and the gas-liquid separator 6 is connected to the compressor 5 through a pipeline; the heating coil 7 is installed inside the gas-liquid separator 6, the oil separator 4 is connected to the heating coil 7 through an oil circuit 1 100, the heating coil 7 is connected to the oil pump 11 through an oil circuit 200, the oil pump 11 is connected to the compressor 5 through an oil circuit 3 300, the compressor 5 is connected to the oil separator 4 through a pipeline, and the exhaust gas of the oil separator 4 goes to the reboiler 17 through a pipeline.

[0046] The compressor unit 3 further includes an oil filter 10 , which is installed on the second oil circuit 200 to filter the oil entering the oil pump 11 .

[0047] The oil circuit 100 is provided with a coil oil regulating valve 8. No matter the machine is started or stopped, the coil oil regulating valve 8 can be fully opened without any operation. There will always be high-temperature oil in the heating coil 7.

[0048] The oil circuit 1 100 is connected to the oil return plate heat exchanger 13 through the oil circuit 4 400, and the oil return plate heat exchanger 13 is connected to the oil circuit 2 200 through the oil circuit 5 500. The oil circuit 5 500 is located between the oil filter 10 and the oil return plate heat exchanger 13, and the oil filter 10 can filter the oil in the oil circuit 5 500.

[0049] The oil circuit 400 is connected to the oil circuit 200 through the oil circuit 700. The oil circuit 700 is located between the oil filter 10 and the oil circuit 400. The oil filter 10 can filter the oil in the oil circuit 700. A water-cooled oil cooler 9 is installed on the oil circuit 700 to cool the lubricating oil by circulating cooling water to ensure that the temperature of the oil circuit 300 is less than 70°C.

[0050] The tower top condenser evaporator 1 is connected to the oil return plate heat exchanger 13 through the oil return pipe 2, and the oil return solenoid valve 14 and the oil return regulating valve 15 are installed on the oil return pipe 2. The oil return solenoid valve 14 is located on the side of the oil return regulating valve 15 away from the oil return plate heat exchanger 13. The heating oil regulating valve 12 is installed on the oil circuit 400, and the oil circuit 700 is located between the heating oil regulating valve 12 and the oil circuit 1 100, and the oil circuit 700 is located between the heating oil regulating valve 12 and the coil oil regulating valve 8.

[0051] The oil return plate heat exchanger 13 and the compressor 5 are connected via an oil circuit 600, and an oil return temperature sensor 16 is installed on the oil circuit 600.

[0052] The implementation principle of the oil circuit system applied to the petrochemical background heat pump process in the embodiment of the present invention is as follows: the lubricating oil and working medium mixed liquid in the tower top condenser evaporator 1 enters the oil return plate heat exchanger 13 through the oil return pipe 2, and is heated by the high-temperature lubricating oil from the oil separator 4, wherein the working medium liquid is vaporized, and after being heated together with the lubricating oil to a temperature 10°C higher than the suction temperature of the compressor 5, it enters the suction pipe of the compressor 5 through the oil circuit 6 600;

[0053] The high-temperature lubricating oil in the oil separator 4 is divided into three paths. The main part is cooled through oil path seven 700 and returns to the compressor 5 through oil path three 300; the second part enters the heating coil 7 through oil path one 100, heats the working fluid in the gas-liquid separator 6, and then enters the compressor 5 through oil path two 200 and oil path three 300; the third part enters the return oil plate heat exchanger 13, heats the lubricating oil and working fluid mixed liquid from oil path two 200 through oil path five 500, and then returns to the compressor 5 through the oil filter 10, the oil pump 11, and the oil path three 300.

[0054] The embodiment of the present invention also discloses an operating method of the oil circuit system as described above, which is applied to a petrochemical background heat pump process.

[0055] Reference Figure 1 and Figure 2 , an operating method of the oil circuit system applied to the petrochemical background heat pump process as described above, comprising the following steps:

[0056] When the oil level height of the oil separator 4 in the compressor unit 3 is reduced to the oil return height for the first time, oil return is required, the heating oil regulating valve 12 is fully opened, the oil return regulating valve 15 is closed, and the oil return solenoid valve 14 is opened. At this time, the oil return temperature sensor 16 has a temperature close to the ambient temperature because there is no oil-liquid mixture (oil and liquid working fluid) flowing in the pipeline; slowly open the oil return regulating valve 15, turn the hand wheel half a circle each time, and observe the value of the oil return temperature sensor 16; just after opening half a circle, as the heated oil flows in the pipeline where the oil return temperature sensor 16 is located, the temperature begins to rise and approaches the temperature of the high-temperature oil of the heat source in the oil separator 4; as the opening of the oil return regulating valve 15 increases, the liquid working fluid in the pipeline increases, and the value of the oil return temperature sensor 16 first approaches the hot oil temperature in the oil separator 4 and then decreases; when it drops to 10°C higher than the suction temperature of the compressor 5, fix the opening position of the oil return regulating valve 15 and do not adjust it anymore. This opening is the maximum oil return capacity of the oil system;

[0057] If such a large amount of oil return is not needed, that is, the amount of oil return needs to be reduced, the oil return regulating valve 15 can be closed down; the criterion for judging whether the amount of oil return is sufficient is that the oil level height of the oil separator can be seen to rise significantly by naked eyes 4 hours after the start of oil return, wherein the oil return time needs to be determined according to the specific size of the equipment oil separator 4;

[0058] After the oil return is completed, the oil return solenoid valve 14 is closed, and other valves remain unchanged. If oil return is needed later, only the oil return solenoid valve 14 needs to be opened and closed.

[0059] In view of the fact that petrochemical projects do not require power, the present invention uses the hot oil in the oil separator 4 of the compressor unit 3 as a heat source for heating the oil-liquid mixture in the oil return pipe 2 and the condensate in the gas-liquid separator 6; the pipeline is simple, the system device is compactly installed, and the operation is convenient; the waste heat of high-temperature lubricating oil is used instead of the sensible heat or electrical energy of high-pressure gas, thereby avoiding the waste of sensible heat of high-pressure gas and improving efficiency.

[0060] For example:

[0061] In a heat pump distillation project for a light hydrocarbon separation tower in a certain refinery, the skid-mounted return oil heating system device in the heat pump compressor unit has the following return oil parameters: high-temperature oil inlet temperature 88°C, compressor 5 suction port temperature 41.3°C, return oil regulating valve 15 opening 3 and 1 / 3 turns, return oil temperature sensor 16 displays a temperature of 60.5°C after the return oil is heated, and the superheat of the recovered oil and working fluid mixture is 19.2°C (i.e. 60.5-41.3°C).

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An operating method for an oil circuit system used in a petrochemical background heat pump process, characterized in that: The oil circuit system comprises a tower top condenser evaporator (1) and a compressor unit (3), wherein the tower top condenser evaporator (1) and the compressor unit (3) are connected via a pipeline, and an oil return pipe (2) is provided between the tower top condenser evaporator (1) and the compressor unit (3), wherein the compressor unit (3) comprises an oil separator (4), a compressor (5), a gas-liquid separator (6), a heating coil (7), an oil pump (11), and an oil return plate heat exchanger (13), wherein the gas-liquid separator (6) and the tower top condenser evaporator (1) are connected via a pipeline, and the gas-liquid separator (6) and the compressor (5) are connected via a pipeline; the heating coil (7) is arranged inside the gas-liquid separator (6), the oil separator (4) and the heating coil (7) are connected via an oil circuit 1 (100), and the heating coil (7) and the oil pump (11) are connected via an oil circuit 2 (210). 00), the oil pump (11) and the compressor (5) are connected via an oil circuit three (300), and the compressor (5) and the oil separator (4) are connected via a pipeline; the oil circuit one (100) is connected to the oil return plate heat exchanger (13) via an oil circuit four (400), and the oil return plate heat exchanger (13) is connected to the oil circuit two (200) via an oil circuit five (500); the tower top condenser evaporator (1) is connected to the oil return plate heat exchanger (13) via an oil return pipe (2), an oil return solenoid valve (14) and an oil return regulating valve (15) are provided on the oil return pipe (2), and a heating oil regulating valve (12) is provided on the oil circuit four (400); the oil return plate heat exchanger (13) and the compressor (5) are connected via an oil circuit six (600), and an oil return temperature sensor (16) is provided on the oil circuit six (600); The operation method comprises the following steps: when the oil level of the oil separator (4) in the compressor unit (3) is reduced to the oil return height for the first time, oil return is required, the heating oil regulating valve (12) is fully opened, the oil return regulating valve (15) is closed, and the oil return solenoid valve (14) is opened. At this time, the oil return temperature sensor (16) has a temperature close to the ambient temperature because there is no oil or liquid working medium flowing in the pipeline; the oil return regulating valve (15) is opened, and the hand wheel is turned half a turn each time to observe the value of the oil return temperature sensor (16); just after opening half a turn, the oil return temperature sensor (16) is turned half a turn. As heated oil flows in the pipeline where the return oil temperature sensor (16) is located, the temperature begins to rise and approaches the temperature of the high-temperature oil in the heat source of the oil separator (4); as the opening of the return oil regulating valve (15) increases, the liquid working medium in the pipeline increases, and the value of the return oil temperature sensor (16) first approaches the temperature of the hot oil in the oil separator (4) and then decreases; when it drops to 10°C higher than the suction temperature of the compressor (5), the opening position of the return oil regulating valve (15) is fixed and will not be adjusted in the future. This opening is the maximum oil return capacity of the oil circuit system; If the oil return volume needs to be reduced, the oil return regulating valve (15) can be closed; After the oil return is completed, the oil return solenoid valve (14) is closed, and other valves remain unchanged. If oil return is required later, only the oil return solenoid valve (14) needs to be opened and closed.

2. The method for operating the oil circuit system for the petrochemical background heat pump process according to claim 1, characterized in that: The compressor unit (3) further comprises an oil filter (10), wherein the oil filter (10) is arranged on the second oil circuit (200).

3. The method for operating the oil circuit system for the petrochemical background heat pump process according to claim 2, characterized in that: The oil circuit five (500) is located between the oil filter (10) and the oil return plate heat exchanger (13).

4. The method for operating the oil circuit system for the petrochemical background heat pump process according to claim 2 is characterized in that: The oil circuit four (400) is connected to the oil circuit two (200) via the oil circuit seven (700), and the oil circuit seven (700) is located between the oil filter (10) and the oil circuit four (400).

5. The method for operating the oil circuit system for the petrochemical background heat pump process according to claim 4 is characterized in that: The oil circuit seven (700) is provided with a water-cooled oil cooler (9).

6. The method for operating the oil circuit system for the petrochemical background heat pump process according to claim 4 is characterized in that: The oil circuit seven (700) is located between the heating oil regulating valve (12) and the oil circuit one (100).

7. The method for operating the oil circuit system for the petrochemical background heat pump process according to claim 1, characterized in that: The oil return solenoid valve (14) is located on a side of the oil return regulating valve (15) away from the oil return plate heat exchanger (13).

8. The method for operating the oil circuit system for the petrochemical background heat pump process according to claim 1, characterized in that: The oil circuit 1 (100) is provided with a coil oil regulating valve (8).

9. The method for operating the oil circuit system for petrochemical background heat pump process according to claim 1, characterized in that: The exhaust gas from the oil separator (4) is sent to the reboiler (17).

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