Defrosting System and Method for an Oil and Gas Recovery Device by Condensation Method

Abstract

The present invention relates to a defrosting system for a condensing oil and gas recovery device, which includes a refrigerant channel. Along the refrigerant flow direction, a compressor, a condenser, and a parallel channel are sequentially arranged on the refrigerant channel. The parallel channel includes a first channel and a second channel. Along the refrigerant flow direction, a first expansion valve / second expansion valve, a first evaporator / second evaporator, and a first outlet valve / second outlet valve are sequentially arranged on the first channel / second channel. When part of the refrigerant undergoes a refrigeration cycle in one of the channels, the other part of the refrigerant performs latent heat defrosting or sensible heat defrosting on the evaporator of this channel in the other channel. Through the combined cooperation of the outlet valve, the expansion valve, and the valve system, the three processes of refrigeration, latent heat defrosting, and sensible heat defrosting can be controlled, increasing the utilization of the latent heat of the compressor exhaust, melting the frost layer on the surface of the heat exchange tube more quickly and effectively, and making the defrosting effect more ideal.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas recovery, and more specifically, to a defrosting system and method for a condensation-type oil and gas recovery device. Background Art

[0002] The condensation oil and gas recovery device utilizes low-temperature technology to reduce the temperature of oil and gas under a certain pressure through heat exchange in a heat exchanger, so that the partial pressure of the oil and gas is greater than the saturated partial pressure at low temperature, and then the oil and gas are condensed into liquid oil products. Due to the complex and diverse components of the oil and gas, when exchanging heat with the low-temperature medium in the heat exchanger, the high-melting-point medium will solidify into a solid state and accumulate on the surface of the heat exchange tube, forming a frosting phenomenon, which deteriorates the heat exchange effect of the heat exchanger and increases the resistance of the oil and gas flow. At this time, it is necessary to defrost the heat exchanger to restore its heat exchange capacity.

[0003] The defrosting methods are divided into two categories: direct contact defrosting outside the tube and hot gas heat transfer defrosting inside the tube; direct contact defrosting outside the tube is to introduce air, oil and gas or other gases into the oil and gas condenser, directly contact with the frost layer on the surface of the heat exchange tube and release heat to melt it to achieve the defrosting purpose. It is more dependent on the stable gas volume and temperature of the oil and gas. When the gas volume of the oil and gas is small or the incoming gas temperature is low, the heat that can be provided is small, the defrosting effect is not ideal, and the problem of long defrosting time is likely to occur; hot gas heat transfer defrosting inside the tube is to pass the compressor exhaust or other heat sources into the heat exchange tube, and remove the frost layer of the heat exchanger through heat transfer. The method of direct sensible heat defrosting of the exhaust is usually to bypass a part of the compressor exhaust into the heat exchanger, and after the exhaust releases heat, it returns to the suction end of the compressor from the heat exchanger. The whole heat release process occurs under low pressure, and the gaseous refrigerant only has a temperature change and will not condense into a liquid refrigerant, that is, only sensible heat is released, and the heat is small, and the defrosting effect is not ideal. Summary of the Invention

[0004] The present invention aims to overcome at least one defect (insufficiency) of the above-mentioned prior art, and provides a defrosting system and method for a condensation-type oil and gas recovery device, which is used to solve the technical problem of how to melt the frost layer on the surface of the heat exchange tube more quickly and effectively.

[0005] The technical solution adopted by the present invention is that a defrosting system for a condensation-type oil and gas recovery device includes a refrigerant channel; along the refrigerant flow direction, a compressor, a condenser, and a parallel channel are sequentially arranged on the refrigerant channel, and the parallel channel includes a first channel and a second channel; along the refrigerant flow direction, a first expansion valve, a first evaporator, and a first outlet valve are sequentially arranged on the first channel, and a second expansion valve, a second evaporator, and a second outlet valve are sequentially arranged on the second channel;

[0006] It also includes a latent heat channel, a sensible heat channel and a valve system. The latent heat channel includes an intake channel with the exhaust end of the compressor respectively connected to the outlets of the first evaporator and the second evaporator, and a liquid outlet channel respectively connected from the inlets of the first evaporator and the second evaporator to the outlet end of the condenser; the sensible heat channel is a channel with the exhaust end of the compressor respectively connected to the inlets of the first evaporator and the second evaporator;

[0007] The valve system is arranged on the latent heat channel and the sensible heat channel and can control the open / closed state of the latent heat channel and the open / closed state of the sensible heat channel.

[0008] In the technical solution of the present invention, the defrosting system operates as follows: The compressor runs to discharge high-temperature and high-pressure gaseous refrigerant. When passing through the condenser, the refrigerant is cooled and condensed by the condenser into high-pressure and normal-temperature liquid refrigerant. The condensed liquid refrigerant separately flows into the first channel or the second channel; the first channel and the second channel can be switched through the oil-gas side valve so that the first evaporator and the second evaporator can achieve rotation defrosting; the first evaporator and the second evaporator can be shell-and-tube heat exchanger tubes, and the heat released by the refrigerant during cooling or condensation can be transferred to the outer surface of the heat exchange tubes to melt the frost layer on the outer surface of the heat exchange tubes; when the first channel is the refrigeration channel, the second channel is the defrosting channel, and when the second channel is the refrigeration channel, the first channel is the defrosting channel; the refrigerant exchanges heat with the oil and gas in the evaporator of the refrigeration channel, absorbs heat and gasifies, and the refrigerant can perform sensible heat defrosting and / or latent heat defrosting on the surface of the evaporator in the channel through heat exchange in the defrosting channel, and the refrigerant flowing out of the evaporator is re-sucked back into the compressor.

[0009] Refrigeration process: In the refrigeration channel, the outlet valve on the channel is opened. When the condensed liquid refrigerant passes through the first expansion valve / second expansion valve, it throttles. The low-temperature and low-pressure gas-liquid two-phase refrigerant enters the first evaporator / second evaporator from the inlet of the first evaporator / second evaporator for gasification. The heat required for the refrigerant to gasify comes from the heat exchanged during the heat exchange between the second evaporator / first evaporator and the external oil and gas. After the refrigerant gasifies into gaseous refrigerant, it flows back into the refrigerant channel from the outlet of the first evaporator / second evaporator and is re-sucked back into the compressor at the suction end of the compressor, completing a refrigeration cycle process.

[0010] Sensible heat defrosting process: The outlet valve on the defrosting channel is opened, and a sensible heat channel is bypassed at the exhaust end of the compressor. After a part of the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust end of the compressor enters the sensible heat channel, it flows into the evaporator from the inlet of the evaporator on the defrosting channel and cools and releases heat naturally. The heat released during the natural cooling of the refrigerant is sensible heat. The sensible heat is transferred from the second evaporator / first evaporator to the outer surface of the heat exchange tube through heat transfer, causing the frost layer on the outer surface of the heat exchange tube to absorb heat and melt, realizing sensible heat defrosting of the heat exchanger; The cooled gaseous refrigerant in the second evaporator / first evaporator flows out of the sensible heat channel, is sucked back into the compressor, and participates in the refrigeration cycle process of the refrigeration channel again.

[0011] Latent heat defrosting process: The outlet valve on the defrosting channel is closed, and a latent heat channel is bypassed at the exhaust end of the compressor. After a part of the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust end of the compressor enters the intake channel, it flows into the second evaporator / first evaporator and is cooled and condensed into a liquid state under the high-pressure state provided by the evaporator. The heat released during the condensation process is latent heat. The latent heat is transferred from the second evaporator / first evaporator to the surface through heat transfer, causing the frost layer on the outer surface of the heat exchange tube to absorb heat and melt, realizing latent heat defrosting of the heat exchanger; The condensed liquid refrigerant in the second evaporator / first evaporator flows to the liquid outlet channel and then flows back to the position between the condenser and the parallel channel in the refrigerant channel, participating in the refrigeration cycle process of the refrigeration channel again.

[0012] The cooperation of the outlet valve and the valve system can control the flow of the refrigerant through the channel. During sensible heat defrosting, the valve system controls the valve to enable the refrigerant to pass through the sensible heat channel; During latent heat defrosting, the valve system controls the valve to enable the refrigerant to pass through the latent heat channel, ensuring that the oil and gas can accurately flow through the correct position to achieve the corresponding working process.

[0013] The latent heat during the latent heat defrosting process is the heat released after the gaseous refrigerant condenses, and the sensible heat during the sensible heat defrosting process is the heat released after the gaseous refrigerant cools. The latent heat is generated after the phase change of the refrigerant, and the sensible heat is only caused by the temperature change without the phase change of the refrigerant. Therefore, the heat release of latent heat defrosting is much larger than that of sensible heat defrosting. Therefore, the latent heat defrosting effect is more ideal. The latent heat defrosting process and the sensible heat defrosting process can be switched to make the defrosting process faster and more thorough.

[0014] Further, the valve system includes a gas volume regulating valve, a latent heat first inlet valve, and a latent heat second inlet valve provided on the intake passage, and a latent heat first outlet valve and a latent heat second outlet valve provided on the liquid outlet passage; one end of the gas volume regulating valve is connected to the exhaust end of the compressor, and the other end is respectively connected to the outlets of the first evaporator and the second evaporator; the latent heat first inlet valve is provided between the gas volume regulating valve and the first evaporator, and the latent heat second inlet valve is provided between the gas volume regulating valve and the second evaporator; one end of the latent heat first outlet valve is connected to the inlet of the first evaporator, and the other end is connected to the outlet end of the condenser; one end of the latent heat second outlet valve is connected to the inlet of the second evaporator, and the other end is connected to the outlet end of the condenser.

[0015] In this technical solution, the intake passage specifically includes: an intake main passage, a first intake passage, and a second intake passage. The liquid outlet passage specifically includes: a first liquid outlet passage and a second liquid outlet passage. The first evaporator is connected to the first intake passage and the first liquid outlet passage. The second evaporator is connected to the second intake passage and the second liquid outlet passage. The first intake passage and the second intake passage are in parallel, and the first liquid outlet passage and the second liquid outlet passage are in parallel. One end of the intake main passage is connected to the inlet of the latent heat intake passage, and the other end of the intake main passage is connected to the parallel inlet of the first intake passage and the second intake passage. The other end of the first intake passage is connected to the outlet of the first evaporator, and the other end of the second intake passage is connected to the outlet of the second evaporator. One end of the first liquid outlet passage is connected to the inlet of the first evaporator, and the other end is connected to the parallel outlet of the liquid outlet passage. One end of the second liquid outlet passage is connected to the inlet of the second evaporator, and the other end is connected to the parallel outlet of the liquid outlet passage. The latent heat intake passage further includes a gas volume regulating valve, a first latent heat inlet valve, and a second latent heat inlet valve. The gas volume regulating valve is arranged on the intake main passage, and the gas volume regulating valve can accurately regulate the bypass flow of the compressor exhaust gas, further regulating the intake air volume of the latent heat passage. The first latent heat inlet valve is arranged on the first intake passage, and the first latent heat inlet valve can control the opening / closing state of the passage between the outlet of the first evaporator and the outlet of the latent heat intake passage, that is, the first intake passage. The second latent heat inlet valve is arranged on the second intake passage, and the second latent heat inlet valve can control the opening / closing state of the passage between the outlet of the second evaporator and the outlet of the latent heat intake passage, that is, the second intake passage. The liquid outlet passage further includes a first latent heat outlet valve and a second latent heat outlet valve. The first latent heat outlet valve is arranged on the first liquid outlet passage, and the first latent heat outlet valve can control the opening / closing state of the passage between the inlet of the first evaporator and the outlet of the liquid outlet passage, that is, the first liquid outlet passage. The second latent heat outlet valve is arranged on the second liquid outlet passage, and the second latent heat outlet valve can control the opening / closing state of the passage between the inlet of the second evaporator and the outlet of the liquid outlet passage, that is, the second liquid outlet passage. In addition, the same function can be achieved by changing the number and type of valves, such as changing the on-off valve to a three-way valve, etc.

[0016] Furthermore, the valve system further includes a first sensible heat inlet valve and a second sensible heat inlet valve arranged on the sensible heat passage. One end of the first sensible heat inlet valve is connected to the exhaust end of the compressor, and the other end is connected to the inlet of the first evaporator. One end of the second sensible heat inlet valve is connected to the exhaust end of the compressor, and the other end is connected to the inlet of the second evaporator.

[0017] In this technical solution, the sensible heat channel specifically includes: a first sensible heat channel and a second sensible heat channel. The first evaporator is connected to the first sensible heat channel, and the second evaporator is connected to the second sensible heat channel. The first sensible heat channel and the second sensible heat channel are in parallel. The sensible heat channel further includes a first sensible heat inlet valve and a second sensible heat inlet valve. The first sensible heat inlet valve is arranged on the first sensible heat channel, and the first sensible heat inlet valve can control the open / closed state of the first sensible heat channel; the second sensible heat inlet valve is arranged on the second sensible heat channel, and the second sensible heat inlet valve can control the open / closed state of the second sensible heat channel.

[0018] The specific scheme for the above valves to control the refrigerant channel is divided into a refrigeration state, a latent heat defrosting state, and a sensible heat defrosting state. Taking the first channel as the refrigeration channel and the second channel as the defrosting channel as an example, in the refrigeration state, the first outlet valve is opened, and all the remaining valves are closed; the refrigerant discharged from the exhaust end of the compressor flows through in sequence: the condenser, the first expansion valve, the first evaporator, and the first outlet valve, and finally flows back to the compressor from the suction end of the compressor. In the latent heat defrosting state, based on the valve state in the refrigeration scheme, the gas volume regulating valve, the second latent heat inlet valve, and the second latent heat outlet valve are opened on this basis; a small part of the refrigerant discharged from the exhaust end of the compressor flows through in sequence: the intake channel, the gas volume regulating valve, the second latent heat inlet valve, the second evaporator, the liquid outlet channel, the second latent heat outlet valve, the first expansion valve, the first evaporator, and the first outlet valve, and finally flows back to the compressor from the suction end of the compressor. In the sensible heat defrosting state, based on the valve state in the refrigeration state, the second sensible heat inlet valve and the second outlet valve are opened on this basis; a small part of the refrigerant discharged from the exhaust end of the compressor flows through in sequence: the intake channel, the second sensible heat inlet valve, the second evaporator, and the second outlet valve, and finally flows back to the compressor from the suction end of the compressor. When the first channel is the defrosting channel and the second channel is the refrigeration channel, the core of the valve control idea is the same as the above scheme.

[0019] Furthermore, the refrigerant channel further includes a gas-liquid separator, and the gas-liquid separator is arranged between the parallel channels and the suction end of the compressor. The gas-liquid separator is used to separate gaseous and liquid refrigerants to prevent a large amount of liquid refrigerant from entering the compressor and causing damage to the compressor.

[0020] Furthermore, the refrigerant channel further includes a liquid receiver, and the liquid receiver is arranged between the outlet of the condenser and the parallel channels. The liquid outlet channel extends from the inlets of the first evaporator and the second evaporator to the position between the condenser and the liquid receiver respectively. The liquid receiver is used to store liquid refrigerant.

[0021] Preferably, the refrigerant channel further includes an oil separator, and the oil separator is arranged at the exhaust end of the compressor; the oil separator is used to separate the compressor lubricating oil carried in the gaseous refrigerant flowing out from the exhaust end of the compressor.

[0022] Preferably, the refrigerant passage further includes a drier filter disposed between the parallel passage and the liquid receiver. The drier filter is used to dry the moisture in the refrigeration system and filter out impurities.

[0023] Furthermore, temperature sensors are provided at the inlets and outlets of the first evaporator and the inlets and outlets of the second evaporator. The temperature sensors can monitor the temperature of the refrigerant when entering and leaving the evaporator, and determine the switching between the refrigeration passage and the defrosting passage by detecting the refrigerant temperature.

[0024] The present invention also provides a defrosting method for a condensing type oil and gas recovery device, which can achieve the defrosting of the above-mentioned condensing oil and gas recovery system; the specific defrosting method is: setting the first passage as the refrigeration passage and the second passage as the defrosting passage, or setting the first passage as the defrosting passage and the second passage as the refrigeration passage; selecting a defrosting mode according to the degree of frost formation, and the defrosting modes include latent heat defrosting, sensible heat defrosting, and the switching between latent heat defrosting and sensible heat defrosting;

[0025] Process of latent heat defrosting: After a part of the exhaust gas of the compressor enters the intake passage, it enters the evaporator from the outlet of the evaporator in the defrosting passage and performs latent heat defrosting on the evaporator, and finally flows through the liquid outlet passage to a position between the condenser and the parallel passage on the refrigerant passage;

[0026] Process of sensible heat defrosting: After a part of the exhaust gas of the compressor enters the sensible heat passage, it enters the evaporator from the inlet of the evaporator in the defrosting passage and performs sensible heat defrosting on the evaporator, and finally flows back to the compressor from the outlet of the evaporator. In this technical solution, the switching between the first passage and the second passage is achieved through the oil and gas side valves, and the corresponding defrosting method is selected according to the degree of frost formation.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. The design of the refrigerant passage maintains the continuity of the oil and gas condensation recovery process.

[0029] 2. By the connection of the refrigerant passage and the joint cooperation of each valve, the refrigeration process, the latent heat defrosting process, and the sensible heat defrosting process are controlled, and the defrosting mode can be easily switched according to the degree of frosting.

[0030] 3. Utilize the latent heat and sensible heat of the compressor exhaust gas to melt the frost layer on the outer surface of the heat exchange tube in two stages of latent heat defrosting and reverse sensible heat defrosting, more quickly and effectively melt the frost layer on the outer surface of the heat exchange tube, make the defrosting effect more ideal, and accelerate the recovery of the heat exchange capacity of the heat exchanger. Description of the Drawings

[0031] Figure 1This is a schematic diagram of the refrigeration process of the present invention.

[0032] Figure 2 This is a schematic diagram of the latent heat defrosting process of the present invention.

[0033] Figure 3 This is a schematic diagram of the sensible heat defrosting process of the present invention.

[0034] Reference numerals in the drawings: Compressor 100; Oil separator 110; Condenser 120; Liquid receiver 130; Drier filter 140; Gas-liquid separator 150; First expansion valve 200; First evaporator 201; Second expansion valve 210; Second evaporator 211; Temperature sensor 300; Temperature sensor 310; Intake passage inlet 400; Latent heat first inlet valve 410; Latent heat second inlet valve 411; Latent heat first outlet valve 420; Latent heat second outlet valve 421; Liquid outlet passage outlet 430; Sensible heat passage inlet 500; Sensible heat first inlet valve 510; Sensible heat second inlet valve 511; First outlet valve 520; Second outlet valve 521; Gas volume regulating valve 600. Detailed implementation manners

[0035] The drawings of the present invention are only for illustrative purposes and should not be construed as a limitation to the present invention. For better illustration of the following embodiments, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0036] Embodiment 1

[0037] As Figure 1 shown, this embodiment is a defrosting system of a condensation method oil and gas recovery device. The specific working components of the defrosting system include: Compressor 100, Oil separator 110, Condenser 120, Liquid receiver 130, Drier filter 140, Gas-liquid separator 150, First expansion valve 200, First evaporator 201, Second expansion valve 210 and Second evaporator 211;

[0038] The defrosting system further includes valves for controlling the refrigeration cycle process, latent heat defrosting process and sensible heat defrosting process, including: Latent heat first inlet valve 410, Latent heat second inlet valve 411, Latent heat first outlet valve 420, Latent heat second outlet valve 421, Sensible heat first inlet valve 510, Sensible heat second inlet valve 511, First outlet valve 520, Second outlet valve 521 and Gas volume regulating valve 600.

[0039] The passage where the first expansion valve 200 and the first evaporator 201 are located is the first passage, and the passage where the second expansion valve 210 and the second evaporator 211 are located is the second passage. The high-temperature and high-pressure gaseous refrigerant discharged by the compressor 100 enters the refrigerant passage and flows to the corresponding passage and then reflows back into the compressor 100. The oil separator 110 separates the compressor lubricant mixed in the refrigerant. The gaseous refrigerant is cooled and condensed into a high-pressure and normal-temperature liquid refrigerant through the condenser 120. The liquid receiver 130 is used to store the liquid refrigerant. The dryer filter 140 is used to dry the moisture in the refrigeration system and filter out impurities. The first expansion valve 200 and the second expansion valve 210 are used for throttling to convert the liquid refrigerant into a low-temperature and low-pressure gas-liquid two-phase refrigerant by reducing the pressure and temperature. The gas-liquid separator 150 is used to separate the gaseous and liquid refrigerants.

[0040] During the refrigeration process, the refrigerant absorbs the heat of the oil and gas in the first evaporator 201 or the second evaporator 211 and vaporizes into a gaseous refrigerant. During the latent heat defrosting process, the first evaporator 201 or the second evaporator 211 provides a high-pressure environment to cool and condense the refrigerant, and releases the latent heat to melt the frost layer on the surface of the evaporator. During the sensible heat process, the refrigerant flows into the first evaporator 201 or the second evaporator 211 to be naturally cooled, and releases the sensible heat to melt the frost layer on the surface of the evaporator.

[0041] The latent heat passage includes an intake passage and a liquid outlet passage. The intake passage specifically includes: an intake main passage, a first intake passage, and a second intake passage. The liquid outlet passage specifically includes: a first liquid outlet passage and a second liquid outlet passage. The first intake passage and the second intake passage are in parallel, and the first liquid outlet passage and the second liquid outlet passage are in parallel. One end of the intake main passage is connected to the intake passage inlet 400, and the other end of the intake main passage is connected to the parallel inlet of the first intake passage and the second intake passage. The first intake passage is connected to the outlet of the first evaporator 201, and the second intake passage is connected to the outlet of the second evaporator 211. One end of the first liquid outlet passage is connected to the inlet of the first evaporator 201, and the other end is connected to the outlet end of the condenser 120. One end of the second liquid outlet passage is connected to the inlet of the second evaporator 211, and the other end is connected to the outlet end of the condenser 120. The gas volume regulating valve 600 is arranged in the intake main passage, and the gas volume regulating valve 600 can accurately regulate the bypass flow rate of the exhaust gas of the compressor 100 to further regulate the intake air volume of the latent heat passage. The first latent heat inlet valve 410 is arranged in the first intake passage, and the first latent heat inlet valve 410 can control the open / closed state of the first intake passage. The second latent heat inlet valve 411 is arranged in the second intake passage, and the second latent heat inlet valve 411 can control the open / closed state of the second intake passage. The first latent heat outlet valve 420 is arranged in the first liquid outlet passage, and the first latent heat outlet valve 420 can control the open / closed state of the first liquid outlet passage. The second latent heat outlet valve 421 is arranged in the second liquid outlet passage, and the second latent heat outlet valve 421 can control the open / closed state of the second liquid outlet passage.

[0042] The sensible heat channels specifically include: a first sensible heat channel and a second sensible heat channel. The first sensible heat channel and the second sensible heat channel are in parallel. One end of the first sensible heat channel and one end of the second sensible heat channel are both connected to the sensible heat channel inlet 500. The other end of the first sensible heat channel is connected to the inlet of the first evaporator 201, and the other end of the second sensible heat channel is connected to the inlet of the second evaporator 211. A first inlet valve 510 is provided in the first sensible heat channel, and the first inlet valve 510 can control the open / closed state of the first sensible heat channel. A second inlet valve 511 is provided in the second sensible heat channel, and the second inlet valve 511 can control the open / closed state of the second sensible heat channel. A first outlet valve 520 is provided in the first channel, and the first outlet valve 520 can control the open / closed state of the first channel. A second outlet valve 521 is provided in the second channel, and the second outlet valve 521 can control the open / closed state of the second channel.

[0043] As Figure 1 shown, the direction of the arrow represents the flow direction of the refrigerant. When the first channel is the refrigeration channel and the second channel is the defrosting channel, it is represented by a solid arrow. When the first channel is the defrosting channel and the second channel is the refrigeration channel, it is represented by a dashed arrow. Taking the first channel as the refrigeration channel and the second channel as the defrosting channel as an example, the refrigeration cycle process of the refrigeration channel is as follows: Open the first expansion valve 200 and the first outlet valve 520, and close other valves. The compressor 100 discharges high-temperature and high-pressure gaseous refrigerant, which successively passes through the oil separator 110, the condenser 120, the liquid receiver 130, the dryer filter 140, the first expansion valve 200, the temperature sensor 300, the first evaporator 201, the first outlet valve 520, and the gas-liquid separator 150 in the order of the gas flow direction, and finally is re-sucked into the compressor 100 to complete the refrigeration cycle.

[0044] As Figure 2As shown, the direction of the arrow represents the flow direction of the refrigerant. The solid arrow indicates the flow direction of the refrigerant in the latent heat channel when the first channel is the latent heat channel, and the dashed arrow indicates the flow direction of the refrigerant in the latent heat channel when the second channel is the latent heat channel. Taking the first channel as the refrigeration channel and the second channel as the latent heat channel as an example, the process of latent heat defrosting is as follows: The settings of all valves are based on the settings during the refrigeration cycle. Additionally, the gas volume regulating valve 600, the latent heat second inlet valve 411, and the latent heat second outlet valve 421 are opened. A small part of the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 100 sequentially passes through the oil separator 110, the intake channel inlet 400, the gas volume regulating valve 600, the latent heat second inlet valve 411, the temperature sensor 310, the second evaporator 201, the temperature sensor 310, the latent heat second outlet valve 421, the liquid outlet channel outlet 430, the liquid receiver 130, the drying filter 140, the first expansion valve 200, the temperature sensor 300, the first evaporator 201, the temperature sensor 300, the first evaporator 201, the first outlet valve 520, the gas-liquid separator 150, and the compressor 100 in the order of the gas flow direction.

[0045] As Figure 3 shown, the direction of the arrow represents the flow direction of the refrigerant, which is indicated by a solid arrow when the first channel is the defrosting channel and the second channel is the refrigeration channel, and is indicated by a dashed arrow when the first channel is the refrigeration channel and the second channel is the defrosting channel. Taking the first channel as the refrigeration channel and the second channel as the defrosting channel as an example, the process of sensible heat defrosting is as follows: The settings of all valves are based on the settings during the refrigeration cycle. Additionally, the sensible heat second inlet valve 511 and the second outlet valve 521 are opened. A small part of the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 100 sequentially passes through the oil separator 110, the sensible heat channel inlet 500, the sensible heat second inlet valve 511, the temperature sensor 310, the second evaporator 211, the temperature sensor 310, the second outlet valve 521, the gas-liquid separator 150, and the compressor 100 in the order of the gas flow direction.

[0046] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solutions of the present invention, rather than limitations on the specific implementation manners of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the claims of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A defrosting method for a condensate oil and gas recovery device, capable of defrosting the defrosting system of the condensate oil and gas recovery device. The defrosting system includes a refrigerant channel. Along the refrigerant flow direction, a compressor, a condenser, and a parallel channel are sequentially arranged on the refrigerant channel. The parallel channel includes a first channel and a second channel. Along the refrigerant flow direction, a first expansion valve, a first evaporator, and a first outlet valve are sequentially arranged on the first channel, and a second expansion valve, a second evaporator, and a second outlet valve are sequentially arranged on the second channel. It is characterized in that the defrosting system further includes a latent heat channel, a sensible heat channel, and a valve system. The latent heat channel includes an intake channel where the exhaust end of the compressor is respectively connected to the outlets of the first evaporator and the second evaporator, and a liquid outlet channel where the inlets of the first evaporator and the second evaporator are respectively connected to the outlet end of the condenser. The sensible heat channel is a channel where the exhaust end of the compressor is respectively connected to the inlets of the first evaporator and the second evaporator. The valve system is arranged on the latent heat channel and the sensible heat channel and can control the open / closed state of the latent heat channel and the open / closed state of the sensible heat channel. The specific defrosting method is as follows: Set the first channel as the refrigeration channel and the second channel as the defrosting channel, or set the first channel as the defrosting channel and the second channel as the refrigeration channel. Defrosting is carried out first by latent heat defrosting and then by sensible heat defrosting. The process of latent heat defrosting: After a part of the exhaust gas of the compressor enters the intake channel, it enters the evaporator from the outlet of the evaporator in the defrosting channel and performs latent heat defrosting on the evaporator, and finally flows to the position between the condenser and the parallel channel on the refrigerant channel through the liquid outlet channel. The process of sensible heat defrosting: After a part of the exhaust gas of the compressor enters the sensible heat channel, it enters the evaporator from the inlet of the evaporator in the defrosting channel and performs sensible heat defrosting on the evaporator, and finally flows back to the compressor from the outlet of the evaporator.

2. The defrosting method of a condensate oil and gas recovery device according to claim 1, characterized in that, The valve system includes a gas volume regulating valve, a latent heat first inlet valve, and a latent heat second inlet valve arranged on the intake channel, and a latent heat first outlet valve and a latent heat second outlet valve arranged on the liquid outlet channel. One end of the gas volume regulating valve is connected to the exhaust end of the compressor, and the other end is respectively connected to the outlets of the first evaporator and the second evaporator. The latent heat first inlet valve is arranged between the gas volume regulating valve and the first evaporator, and the latent heat second inlet valve is arranged on the gas volume regulating valve and the second evaporator. One end of the latent heat first outlet valve is connected to the inlet of the first evaporator, and the other end is connected to the outlet end of the condenser. One end of the latent heat second outlet valve is connected to the inlet of the second evaporator, and the other end is connected to the outlet end of the condenser.

3. The defrosting method of a condensate oil and gas recovery device according to claim 1, characterized in that, The valve system further includes a sensible heat first inlet valve and a sensible heat second inlet valve arranged on the sensible heat channel. One end of the sensible heat first inlet valve is connected to the exhaust end of the compressor, and the other end is connected to the inlet of the first evaporator. One end of the sensible heat second inlet valve is connected to the exhaust end of the compressor, and the other end is connected to the inlet of the second evaporator.

4. A defrosting method for a condensate oil and gas recovery device according to any one of claims 1-3, characterized in that, The refrigerant channel further includes a gas-liquid separator, and the gas-liquid separator is arranged between the parallel channel and the suction end of the compressor.

5. A defrosting method for a condensate-based oil and gas recovery device according to any one of claims 1-3, characterized in that, The refrigerant passage further includes a liquid receiver, and the liquid receiver is disposed between the outlet of the condenser and the parallel passage. The liquid outlet passage extends from the inlets of the first evaporator and the second evaporator respectively to a position between the condenser and the liquid receiver.

6. A defrosting method for a condensate oil and gas recovery device according to any one of claims 1-3, characterized in that, The refrigerant passage further includes an oil separator, and the oil separator is disposed at the exhaust end of the compressor.

7. A defrosting method for an oil and gas recovery device by the condensation method according to claim 5, characterized in that, The refrigerant passage further includes a dryer filter, and the dryer filter is disposed between the parallel passage and the liquid receiver.

8. A defrosting method for a condensate oil and gas recovery device according to any one of claims 1 to 3, characterized in that, Temperature sensors are provided at the inlets and outlets of the first evaporator and the inlets and outlets of the second evaporator.

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