Oil field sewage waste heat and terrestrial heat combined heat supply system

Abstract

The oil field sewage waste heat and terrestrial heat combined heat supply system comprises a sewage heat exchange unit, a terrestrial heat exchange unit and a heat utilization unit, the sewage heat exchange unit comprises a first heat pump, the inlet end of an evaporator of the first heat pump communicates with a sewage outlet pipe, and the outlet end of the evaporator of the first heat pump communicates with a sewage return pipe; the inlet end of a condenser of the first heat pump communicates with the water supply flow path, and the outlet end communicates with the heat supply flow path. The geothermal heat exchange unit comprises a second heat pump, the inlet end of an evaporator of the second heat pump communicates with a water outlet pipe of the geothermal well, the water outlet end of the evaporator communicates with a water return pipe of the geothermal well, the inlet end of a condenser of the second heat pump communicates with the water supply flow path, and the outlet end of the condenser communicates with the heat supply flow path. The heat utilization unit comprises at least one heat utilization heat exchanger, and the heat supply flow path and the water supply flow path exchange heat at the heat utilization heat exchanger. According to the oil field sewage waste heat and terrestrial heat supply oil field heat demand, pollution and energy consumption can be reduced, and energy conservation, emission reduction and cost reduction are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of energy utilization, and in particular to a combined heating system of oilfield waste heat and geothermal energy. Background Art

[0002] In oilfield production, a large amount of energy is consumed to meet the heat needs of dehydrating water-containing crude oil, heating finished oil, blending heating, and user heating. At present, the heat demand of oilfields is mainly provided by natural gas and coal, which has the problems of high pollution, high energy consumption, and is not conducive to energy conservation, emission reduction, and cost reduction. Summary of the invention

[0003] The main purpose of the present invention is to propose a combined heating system of oil field waste heat and geothermal energy, aiming to solve the problem that the existing oil field heat demand mainly relies on natural gas and coal as fuel to provide heat, which has great pollution, high energy consumption, and is not conducive to energy conservation, emission reduction and cost reduction.

[0004] To achieve the above-mentioned purpose, the present invention proposes a combined heating system of oilfield sewage waste heat and geothermal energy, comprising a sewage heat exchange unit, a geothermal heat exchange unit and a heat using unit, wherein the sewage heat exchange unit comprises a first heat pump, the inlet end of the evaporator of the first heat pump is connected to the sewage outlet pipe, and the outlet end is connected to the sewage return pipe, the inlet end of the condenser of the first heat pump is connected to the water supply flow path, and the outlet end is connected to the heat supply flow path; the geothermal heat exchange unit comprises a second heat pump, the inlet end of the evaporator of the second heat pump is connected to the outlet pipe of the geothermal well, the water outlet end is connected to the return pipe of the geothermal well, the inlet end of the condenser of the second heat pump is connected to the water supply flow path, and the outlet end is connected to the heat supply flow path; the heat using unit comprises at least one heat using heat exchanger, and the heat supply flow path and the water supply flow path perform heat exchange at the heat using heat exchanger.

[0005] Optionally, the water supply flow path includes a water supply trunk and a first water supply lead-out branch and a second water supply lead-out branch both connected to the water supply trunk, the first water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the first heat pump, and the second water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the second heat pump, wherein:

[0006] The first water supply outlet branch is provided with a first regulating valve; and / or,

[0007] A second regulating valve is provided on the second water supply outlet branch.

[0008] Optionally, the sewage heat exchange unit also includes a third heat pump, the inlet end of the evaporator of the third heat pump is connected to the outlet end of the evaporator of the first heat pump, and the outlet end is connected to the sewage return pipe, the inlet end of the condenser of the third heat pump is connected to the water supply path, and the outlet end is connected to the heat supply path.

[0009] Optionally, the outlet end of the evaporator of the first heat pump is connected to the sewage return pipe through a first pipe, and the inlet end of the evaporator of the third heat pump is connected to the first pipe through a second pipe. A first stop valve is provided on the first pipe, and the first stop valve is located between the second pipe and the sewage return pipe, so that the outlet end of the evaporator of the first heat pump is connected to the sewage return pipe or to the inlet end of the evaporator of the third heat pump.

[0010] Optionally, the water supply flow path includes a water supply trunk and a first water supply lead-out branch, a second water supply lead-out branch, and a third water supply lead-out branch, all of which are connected to the water supply trunk. The first water supply lead-out branch guides the water on the water supply trunk to the inlet end of the condenser of the first heat pump, the second water supply lead-out branch guides the water on the water supply trunk to the inlet end of the condenser of the second heat pump, and the third water supply lead-out branch guides the water on the water supply trunk to the inlet end of the condenser of the third heat pump, wherein:

[0011] The first water supply outlet branch is provided with a first regulating valve; and / or,

[0012] A second regulating valve is provided on the second water supply outlet branch; and / or,

[0013] The third water supply outlet branch is provided with a third regulating valve.

[0014] Optionally, the geothermal heat exchange unit also includes a plate heat exchanger, which is installed between the geothermal well and the second heat pump, the inlet end of one flow channel of the plate heat exchanger is connected to the outlet pipe of the geothermal well, and the outlet end is connected to the return pipe of the geothermal well, the inlet end of another flow channel of the plate heat exchanger is connected to the outlet end of the evaporator of the second heat pump, and the outlet end is connected to the inlet end of the evaporator of the second heat pump.

[0015] Optionally, the geothermal well is converted from an abandoned oil well.

[0016] Optionally, the heat supply flow path includes a heat supply trunk and at least one heat consumption branch both connected to the heat supply trunk, the heat supply trunk is connected to an outlet end of the condenser of the first heat pump and an outlet end of the condenser of the second heat pump, and the heat consumption heat exchanger is provided on at least one of the heat consumption branches;

[0017] The water supply flow path includes a water supply trunk and at least one water supply introduction branch connected to the water supply trunk, the water supply trunk is connected to the inlet end of the condenser of the first heat pump and the inlet end of the condenser of the second heat pump, and the heat exchanger is also provided on at least one of the water supply introduction branches;

[0018] The heat exchanger includes at least one of a dehydration heat exchanger, a hot oil heat exchanger, a blending heat exchanger and a hot water heat exchanger.

[0019] Optionally, a second stop valve is provided on the heat-using branch; and / or,

[0020] The water supply trunk line is provided with a system circulation pump.

[0021] Optionally, the dehydration heat exchanger is a shell and tube heat exchanger; and / or,

[0022] The hot oil heat exchanger is a shell and tube heat exchanger; and / or,

[0023] The mixing heat exchanger is a shell and tube heat exchanger; and / or,

[0024] The hot water heat exchanger is a plate heat exchanger.

[0025] In the technical solution of the present invention, oilfield sewage enters the evaporator of the first heat pump for heat exchange, and the waste heat of the oilfield sewage is transferred to the water entering the condenser of the first heat pump, and the heated water enters the heat supply flow path to provide heat to the heat-using unit; the circulating water of the geothermal well enters the evaporator of the second heat pump for heat exchange, and the geothermal heat is transferred to the water entering the condenser of the second heat pump, and the heated water enters the heat supply flow path to provide heat to the heat-using unit; the heat demand of the oilfield is supplied by the waste heat of oilfield sewage and geothermal heat, which can reduce pollution and energy consumption, and is conducive to energy conservation, emission reduction and cost reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0027] Figure 1 This is a structural schematic diagram of an embodiment of the oilfield sewage waste heat and geothermal combined heating system provided by the present invention.

[0028] Description of Figure Numbers:

[0029] Label name Label name 1 First heat pump 12 Mixed heat exchanger 2 Geothermal Wells 13 Hot water heat exchanger 3 Second heat pump 14 Second stop valve 4 First regulating valve 15 Sewage lifting pump 5 Second regulating valve 16 Deep well pump 6 The third heat pump 17 Heat pump circulation pump 7 First stop valve 18 System circulation pump 8 The third regulating valve 19 Dehydration circulation pump 9 Plate Heat Exchanger 20 Hot oil circulation pump 10 Dehydration heat exchanger 21 Mixing circulation pump 11 Hot oil heat exchanger 22 Heating circulation pump

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] In oilfield production, a large amount of energy is consumed to meet the heat needs of dehydrating water-containing crude oil, heating finished oil, blending heating, and user heating. At present, the heat demand of oilfields is mainly provided by natural gas and coal, which has the problems of high pollution, high energy consumption, and is not conducive to energy conservation, emission reduction, and cost reduction.

[0035] In view of this, the present invention proposes a combined heating system of oilfield waste heat and geothermal energy, which supplies the heating demand of the oilfield through the waste heat of oilfield sewage and geothermal energy, can reduce pollution and energy consumption, and is conducive to energy conservation, emission reduction and cost reduction. Figure 1 This is an embodiment of the oilfield sewage waste heat and geothermal combined heating system provided by the present invention.

[0036] In the embodiments of the present invention, please refer to Figure 1The oilfield sewage waste heat and geothermal combined heating system includes a sewage heat exchange unit, a geothermal heat exchange unit and a heat using unit. The sewage heat exchange unit includes a first heat pump 1, the inlet end of the evaporator of the first heat pump 1 is connected to the sewage outlet pipe, and the outlet end is connected to the sewage return pipe. The inlet end of the condenser of the first heat pump 1 is connected to the water supply flow path, and the outlet end is connected to the heat supply flow path; the geothermal heat exchange unit includes a second heat pump 3, the inlet end of the evaporator of the second heat pump 3 is connected to the outlet pipe of the geothermal well 2, the water outlet end is connected to the return pipe of the geothermal well 2, the inlet end of the condenser of the second heat pump 3 is connected to the water supply flow path, and the outlet end is connected to the heat supply flow path; the heat using unit includes at least one heat using heat exchanger, and the heat supply flow path and the water supply flow path are heat exchanged at the heat using heat exchanger.

[0037] In the technical solution of the present invention, oilfield sewage enters the evaporator of the first heat pump 1 for heat exchange, and the waste heat of the oilfield sewage is transferred to the water in the condenser entering the first heat pump 1, and the heated water enters the heat supply flow path to provide heat to the heat-using unit; the circulating water of the geothermal well 2 enters the evaporator of the second heat pump 3 for heat exchange, and the geothermal heat is transferred to the water in the condenser entering the second heat pump 3, and the heated water enters the heat supply flow path to provide heat to the heat-using unit; the heat demand of the oilfield is supplied by the waste heat of oilfield sewage and geothermal heat, which can reduce pollution and energy consumption, and is conducive to energy conservation, emission reduction and cost reduction.

[0038] It can be understood that the sewage outlet pipe is provided with a sewage lifting pump 15, which makes the circulation of sewage smoother and the supply of sewage can be controlled at the same time; the outlet pipe of the geothermal well 2 is provided with a deep well pump 16, which makes the circulation of circulating water of the geothermal well 2 smoother and the supply of circulating water of the geothermal well 2 can be controlled at the same time.

[0039] In some embodiments of the present invention, the water supply flow path includes a water supply trunk and a first water supply outlet branch and a second water supply outlet branch both connected to the water supply trunk, the first water supply outlet branch guides the water on the water supply trunk to the inlet end of the condenser of the first heat pump 1, and the second water supply outlet branch guides the water on the water supply trunk to the inlet end of the condenser of the second heat pump 3, wherein: a first regulating valve 4 is provided on the first water supply outlet branch. The water entering the water supply trunk is divided through the first water supply outlet branch and the second water supply outlet branch, and enters the condenser of the first heat pump 1 and the condenser of the second heat pump 3 for heat exchange respectively; a first regulating valve 4 is provided on the first water supply outlet branch, and the flow rate of water entering the condenser of the first heat pump 1 can be adjusted through the second regulating valve 5, thereby adjusting the temperature of the heated water, and controlling the water supply at the same time.

[0040] In some embodiments of the present invention, a second regulating valve 5 is provided on the second water supply outlet branch, and the second regulating valve 5 can adjust the flow of water entering the condenser of the second heat pump 3, thereby adjusting the temperature of the heated water, and at the same time controlling the water supply.

[0041] In some embodiments of the present invention, the sewage heat exchange unit further includes a third heat pump 6, the inlet end of the evaporator of the third heat pump 6 is connected to the outlet end of the evaporator of the first heat pump 1, and the outlet end is connected to the sewage return pipe, the inlet end of the condenser of the third heat pump 6 is connected to the water supply flow path, and the outlet end is connected to the heat supply flow path. The oilfield sewage after heat exchange by the first heat pump 1 enters the evaporator of the third heat pump 6 for heat exchange, and further transfers the waste heat of the oilfield sewage to the water entering the condenser of the third heat pump 6. The heated water enters the heat supply flow path and is used to heat the heat unit; the third heat pump 6 performs secondary heat exchange on the oilfield sewage, which can improve the utilization rate of the waste heat of the oilfield sewage and further supply the heat demand of the oilfield.

[0042] In some embodiments of the present invention, the outlet end of the evaporator of the first heat pump 1 is connected to the sewage return pipe through a first pipe, and the inlet end of the evaporator of the third heat pump 6 is connected to the first pipe through a second pipe. A first stop valve 7 is provided on the first pipe, and the first stop valve 7 is located between the second pipe and the sewage return pipe, so that the outlet end of the evaporator of the first heat pump 1 is connected to the sewage return pipe or to the inlet end of the evaporator of the third heat pump 6. The first stop valve 7 is opened, the outlet end of the evaporator of the first heat pump 1 is connected with the sewage return pipe, and the sewage after heat exchange by the first heat pump 1 enters the sewage return pipe, realizing the primary heat exchange of the oilfield sewage; the first stop valve 7 is closed, the outlet end of the evaporator of the first heat pump 1 is connected with the inlet end of the evaporator of the third heat pump 6, and the oilfield sewage after heat exchange by the first heat pump 1 enters the evaporator of the third heat pump 6 for heat exchange, realizing the secondary heat exchange of the oilfield sewage; by controlling the first stop valve 7, the primary heat exchange or secondary heat exchange of the oilfield sewage is realized to meet the different heat requirements of the oilfield, and the operation is simple and easy to control.

[0043] In some embodiments of the present invention, the water supply flow path includes a water supply trunk and a first water supply lead-out branch, a second water supply lead-out branch, and a third water supply lead-out branch, all of which are connected to the water supply trunk. The first water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the first heat pump 1, the second water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the second heat pump 3, and the third water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the third heat pump 6, wherein: a third regulating valve 8 is provided on the third water supply lead-out branch. The water entering the water supply trunk is divided through the first water supply lead-out branch, the second water supply lead-out branch, and the third water supply lead-out branch, and enters the condenser of the first heat pump 1, the condenser of the second heat pump 3, and the condenser of the third heat pump 6 for heat exchange, respectively. The third water supply lead-out branch is provided with a third regulating valve 8, which can adjust the flow of water entering the condenser of the third heat pump 6, thereby adjusting the temperature of the heated water, and at the same time controlling the water supply. It can be understood that the water supply trunk line can be connected to a water replenishment pipe for replenishing water to the water supply trunk line to ensure water supply demand.

[0044] In some embodiments of the present invention, the geothermal heat exchange unit also includes a plate heat exchanger 9, which is installed between the geothermal well 2 and the second heat pump 3, the inlet end of one flow channel of the plate heat exchanger 9 is connected to the outlet pipe of the geothermal well 2, and the outlet end is connected to the return pipe of the geothermal well 2, the inlet end of another flow channel of the plate heat exchanger 9 is connected to the outlet end of the evaporator of the second heat pump 3, and the outlet end is connected to the inlet end of the evaporator of the second heat pump 3. Water circulates between another flow channel of the plate heat exchanger 9 and the evaporator of the second heat pump 3. The circulating water from the geothermal well 2 enters one of the flow channels of the plate heat exchanger 9 and exchanges heat with the water in the other flow channel. The heated water in the other flow channel then enters the evaporator of the second heat pump 3 for heat exchange and transfers the heat to the water entering the condenser of the second heat pump 3. The heated water in the condenser of the second heat pump 3 enters the heat supply flow path to supply heat to the heat-using unit. The water that is cooled after heat exchange in the evaporator of the second heat pump 3 enters another flow channel of the plate heat exchanger 9 for heat exchange. The plate heat exchanger 9 is arranged between the geothermal well 2 and the second heat pump 3 for heat exchange. The flow rate of the circulating water in the other flow channel of the plate heat exchanger 9 is easy to adjust, so as to adjust the temperature of the heated water. At the same time, the plate heat exchanger 9 also plays a filtering role. The silt that may exist in the circulating water of the geothermal well 2 will be deposited in one of the flow channels of the plate heat exchanger 9, which can effectively prevent the silt from entering the second heat pump 3, and the cleaning of the plate heat exchanger 9 is more convenient.

[0045] It can be understood that a water replenishment pipe is connected between the outlet end of the evaporator of the second heat pump 3 and the inlet end of the other flow channel of the plate heat exchanger 9 for replenishing water to ensure the water demand of the circulating water in the other flow channel of the plate heat exchanger 9; a heat pump circulation pump 17 can be arranged between the outlet end of the evaporator of the second heat pump 3 and the inlet end of the other flow channel of the plate heat exchanger 9, so that the circulation of circulating water between the plate heat exchanger 9 and the second heat pump 3 is smoother and the water supply can be controlled at the same time.

[0046] In some embodiments of the present invention, the geothermal well 2 is transformed from an abandoned oil well. Making full use of the abandoned oil wells in the oil field can reduce costs.

[0047] In some embodiments of the present invention, the heat supply flow path includes a heat supply trunk and at least one heat consumption branch connected to the heat supply trunk, the heat supply trunk is connected to the outlet end of the condenser of the first heat pump 1 and the outlet end of the condenser of the second heat pump 3, and the heat consumption heat exchanger is provided on at least one of the heat consumption branches;

[0048] The water supply flow path includes a water supply trunk and at least one water supply introduction branch connected to the water supply trunk, the water supply trunk is connected to the inlet end of the condenser of the first heat pump 1 and the inlet end of the condenser of the second heat pump 3, and the heat exchanger is also provided on at least one of the water supply introduction branches;

[0049] The heat exchanger includes at least one of a dehydration heat exchanger 10 , a hot oil heat exchanger 11 , a blending heat exchanger 12 and a hot water heat exchanger 13 .

[0050] The water heated in the first heat pump 1, the second heat pump 3 and the third heat pump 6 enters the heat supply trunk line, and then enters the heat exchanger through the heat use branch line to supply the heat demand of the oil field. The water cooled after heat exchange in the heat exchanger enters the water supply trunk line through the water supply introduction branch line, and then supplies water to the first heat pump 1, the second heat pump 3 and the third heat pump 6 through the water supply trunk line, forming a water cycle. The system structure is compact, and water is saved, which is conducive to reducing costs. The heat exchanger includes at least one of the dehydration heat exchanger 10, the hot oil heat exchanger 11, the blending heat exchanger 12 and the hot water heat exchanger 13, which can be one of them, or multiple or all of them. The number of the heat use branch lines and the water supply introduction branches is set corresponding to the number of the heat exchangers.

[0051] The inlet end of one of the flow channels of the dehydration heat exchanger 10 is in communication with the corresponding heat-using branch, and the outlet end is in communication with the corresponding water supply introduction branch. The inlet end of another flow channel of the dehydration heat exchanger 10 is in communication with the water-containing oil pipe, and the outlet end is in communication with the dehydration oil pipe. The water-containing crude oil enters the other flow channel of the dehydration heat exchanger 10 through the water-containing oil pipe for heat exchange. The water-containing crude oil is heated by the water in one of the flow channels of the dehydration heat exchanger 10, and then flows out through the dehydration oil pipe to achieve dehydration of the water-containing crude oil. It can be understood that a dehydration circulation pump 19 can be provided on the water-containing oil pipe, so that the circulation of the water-containing crude oil is smoother and the supply of the water-containing crude oil can be controlled at the same time.

[0052] The inlet end of one of the flow channels of the hot oil heat exchanger 11 is connected to the corresponding heat-using branch, and the outlet end is connected to the corresponding water supply introduction branch. The inlet end of another flow channel of the hot oil heat exchanger 11 is connected to the low-temperature oil pipe, and the outlet end is connected to the high-temperature oil pipe. The low-temperature crude oil enters the other flow channel of the hot oil heat exchanger 11 through the low-temperature oil pipe for heat exchange. The low-temperature crude oil is heated by the water in one of the flow channels of the hot oil heat exchanger 11, and then flows out through the high-temperature oil pipe to achieve the heating of the crude oil. It can be understood that a hot oil circulation pump 20 can be set on the low-temperature oil pipe, so that the circulation of the low-temperature crude oil is smoother, and the supply of the low-temperature crude oil can be controlled at the same time.

[0053] The inlet end of one of the flow channels of the blending heat exchanger 12 is connected to the corresponding heat-using branch, and the outlet end is connected to the corresponding water supply inlet branch. The inlet end of another flow channel of the blending heat exchanger 12 is connected to the low-temperature oily sewage pipe, and the outlet end is connected to the high-temperature oily sewage pipe. The low-temperature oily sewage enters the other flow channel of the blending heat exchanger 12 through the low-temperature oily sewage pipe for heat exchange. The low-temperature oily sewage is heated by the water in one of the flow channels of the blending heat exchanger 12, and then flows out through the high-temperature oily sewage pipe to achieve the heating of the oily sewage. It can be understood that a blending circulation pump 21 can be provided on the low-temperature oily sewage pipe, so that the circulation of the low-temperature oily sewage is smoother and the supply of the low-temperature oily sewage can be controlled at the same time.

[0054] The inlet end of one of the flow channels of the hot water heat exchanger 13 is connected to the corresponding heat branch, and the outlet end is connected to the corresponding water supply introduction branch. The inlet end of another flow channel of the hot water heat exchanger 13 is connected to a low-temperature water pipe, and the outlet end is connected to a high-temperature water pipe. The user's heating return water enters another flow channel of the hot water heat exchanger 13 through the low-temperature water pipe for heat exchange. The user's heating return water is heated by the water in one of the flow channels of the hot water heat exchanger 13, and then flows out through the high-temperature water pipe to achieve user heating and meet the heating needs of heating users. It can be understood that a heating circulation pump 22 can be set on the low-temperature water pipe, so that the circulation of user heating return water is smoother, and the supply of user heating return water can be controlled at the same time. In the non-heating season, the heating circulation pump 22 is turned off.

[0055] In some embodiments of the present invention, the heat-using branch is provided with a second stop valve 14. The second stop valve 14 controls the heat supply trunk to supply heated water to the corresponding heat-using branch, so as to meet different heat demands in the oil field.

[0056] In some embodiments of the present invention, a system circulation pump 18 is provided on the water supply trunk line. The system circulation pump 18 can make the water flow in the water supply flow path smoother and control the water supply. It is understandable that the system circulation pump 18 can be one or two, and the two system circulation pumps 18 are connected in parallel. When one of the system circulation pumps 18 is in use, the other system circulation pump 18 is in standby, which is conducive to ensuring the operation of the system.

[0057] In some embodiments of the present invention, the dehydration heat exchanger 10 is a shell and tube heat exchanger. The dehydration heat exchanger 10 is used to heat the water-containing crude oil. The shell and tube heat exchanger ensures the heat exchange effect while allowing the water-containing crude oil to flow smoothly.

[0058] In some embodiments of the present invention, the hot oil heat exchanger 11 is a shell and tube heat exchanger. The hot oil heat exchanger 11 is used to heat crude oil, and the shell and tube heat exchanger ensures the heat exchange effect while making the crude oil flow smoothly.

[0059] In some embodiments of the present invention, the mixing heat exchanger 12 is a shell and tube heat exchanger. The mixing heat exchanger 12 is used to heat the oily wastewater. The shell and tube heat exchanger ensures the heat exchange effect while making the oily wastewater flow smoothly.

[0060] In some embodiments of the present invention, the hot water heat exchanger 13 is a plate heat exchanger. The hot water heat exchanger 13 is used to heat the return water for user heating. The plate heat exchanger has good heat exchange effect and smooth water circulation.

[0061] The following is a description of the operation of three modes of the oilfield waste heat and geothermal combined heating system of the present invention.

[0062] The dehydration heat load, hot oil heat load, blending heat load and user heating heat load in the oil field station are set to 8300KW in total. The waste heat from oilfield sewage and geothermal heat can provide 8360KW of heat, which can meet the heat demand of the oil field station. Among them, the waste heat from oilfield sewage can provide 7706KW of heat, and the geothermal heat can provide 654KW of heat.

[0063] The first mode: primary heating using waste heat from oilfield sewage

[0064] When the heat required by the oilfield station is lower than 3837KW, the primary heating of the waste heat from oilfield sewage can meet the heat demand of the oilfield station, the first heat pump 1 is started, and the second heat pump 3 and the third heat pump 6 are turned off.

[0065] Sewage heat exchange unit: the first stop valve 7 is opened; the high-temperature sewage at 35°C of the oilfield station directly enters the evaporator of the first heat pump 1 for heat exchange through the sewage lift pump 15, and the low-temperature sewage at 26°C after heat exchange and cooling is reinjected through the opened first stop valve 7.

[0066] Water supply pipeline and heat supply pipeline: the second stop valve 14 on each of the heat branches is opened, the first regulating valve 4 is opened, and the system circulation pump 18 is opened; the first heat pump 1 heats the 60°C water provided by the first water supply outlet branch to 75°C, and then enters one of the flow channels of the dehydration heat exchanger 10, the hot oil heat exchanger 11, the blending heat exchanger 12 and the hot water heat exchanger 13 through the opened second stop valves 14 for heat exchange. The 75°C water is cooled to 60°C after heat exchange, and the 60°C water is then transported to the first water supply outlet branch through the system circulation pump 18, and enters the condenser of the first heat pump 1 through the opened first regulating valve 4 for heat exchange, forming a water cycle.

[0067] Heat unit:

[0068] For the dehydration heat exchanger 10, the dehydration circulation pump 19 transports the 45°C water-containing crude oil to another flow channel of the dehydration heat exchanger 10 for heat exchange, and heats the water-containing crude oil to 70°C, thereby achieving dehydration of the water-containing crude oil;

[0069] For the hot oil heat exchanger 11, the hot oil circulation pump 20 transports the 43°C crude oil to another flow channel of the hot oil heat exchanger 11 for heat exchange, and heats the low-temperature crude oil to 70°C, thereby achieving heating of the crude oil;

[0070] For the blending heat exchanger 12, the blending circulation pump 21 transports the 42°C oily wastewater to another flow channel of the blending heat exchanger 12 for heat exchange, and heats the low-temperature oily wastewater to 65°C for use;

[0071] For the hot water heat exchanger 13, the heating circulation pump 22 transports the user heating return water at 40°C to another flow channel of the hot water heat exchanger 13 for heat exchange, heats the user heating return water to 65°C and sends it to the user for heating, thereby meeting the heating needs of the heating users; during the heating season, the heating circulation pump 22 and the corresponding second stop valve 14 on the heating branch are both opened; during the non-heating season, the heating circulation pump 22 and the corresponding second stop valve 14 on the heating branch are both closed.

[0072] The second mode: secondary heating of waste heat from oilfield sewage

[0073] When the heat required by the oil field station is between 3837KW and 7706KW, the primary heating of the waste heat from the oil field sewage cannot meet the heat demand of the oil field station, and the secondary heating of the waste heat from the oil field sewage is used to meet the heat demand of the oil field station; the first heat pump 1 and the third heat pump 6 are started, and the second heat pump 3 is turned off;

[0074] Sewage heat exchange unit: the first stop valve 7 is closed; the high-temperature sewage at 35°C of the oilfield station directly enters the evaporator of the first heat pump 1 through the sewage lift pump 15 for primary heat exchange, and the low-temperature sewage at 26°C after heat exchange and cooling enters the evaporator of the third heat pump 6 for secondary heat exchange, and the low-temperature sewage at 17°C after heat exchange and cooling is reinjected.

[0075] Water supply pipeline and heat supply pipeline: the second stop valve 14 on each heat branch is opened, the first regulating valve 4 and the third regulating valve 8 are opened, and the system circulation pump 18 is opened; the first heat pump 1 heats the 60°C water provided by the first water supply outlet branch to 75°C, and the third heat pump 6 heats the 60°C water provided by the third water supply outlet branch to 75°C. The water heated by the first heat pump 1 and the third heat pump 6 enters the heat supply main line, and then passes through the opened second stop valves. 14 respectively enters one of the flow channels of the dehydration heat exchanger 10, the hot oil heat exchanger 11, the blending heat exchanger 12 and the hot water heat exchanger 13 for heat exchange. The 75°C water is cooled to 60°C after heat exchange. The 60°C water is then transported to the first water supply outlet branch and the third water supply outlet branch through the system circulation pump 18, and respectively enters the condensers of the first heat pump 1 and the third heat pump 6 through the opened first regulating valve 4 and the opened third regulating valve 8 for heat exchange, forming a water cycle.

[0076] Heat unit:

[0077] For the dehydration heat exchanger 10, the dehydration circulation pump 19 transports the 45°C water-containing crude oil to another flow channel of the dehydration heat exchanger 10 for heat exchange, and heats the water-containing crude oil to 70°C, thereby achieving dehydration of the water-containing crude oil;

[0078] For the hot oil heat exchanger 11, the hot oil circulation pump 20 transports the 43°C crude oil to another flow channel of the hot oil heat exchanger 11 for heat exchange, and heats the low-temperature crude oil to 70°C, thereby achieving heating of the crude oil;

[0079] For the blending heat exchanger 12, the blending circulation pump 21 transports the 42°C oily wastewater to another flow channel of the blending heat exchanger 12 for heat exchange, and heats the low-temperature oily wastewater to 65°C for use;

[0080] For the hot water heat exchanger 13, the heating circulation pump 22 transports the user heating return water at 40°C to another flow channel of the hot water heat exchanger 13 for heat exchange, heats the user heating return water to 65°C and sends it to the user for heating, thereby meeting the heating needs of the heating users; during the heating season, the heating circulation pump 22 and the corresponding second stop valve 14 on the heating branch are both opened; during the non-heating season, the heating circulation pump 22 and the corresponding second stop valve 14 on the heating branch are both closed.

[0081] The third mode: Combined heating of waste heat from oilfield sewage and geothermal energy

[0082] Since the maximum flow rate of oilfield station sewage is 300t / h, the maximum heat provided by oilfield sewage is 7706KW. As the heat demand of oilfield stations increases, the heat provided by oilfield sewage cannot meet the heat demand of oilfield stations. The geothermal well 2 transformed from the abandoned wells in the oilfield is used to provide geothermal heat to meet the heat demand of the oilfield stations.

[0083] Sewage heat exchange unit: the first stop valve 7 is closed; the high-temperature sewage at 35°C of the oilfield station directly enters the evaporator of the first heat pump 1 through the sewage lift pump 15 for primary heat exchange, and the low-temperature sewage at 26°C after heat exchange and cooling enters the evaporator of the third heat pump 6 for secondary heat exchange, and the low-temperature sewage at 17°C after heat exchange and cooling is reinjected.

[0084] Geothermal heat exchange unit: the deep well pump 16 and the heat pump circulation pump 17 are turned on; the deep well pump 16 draws up the 30°C circulating water from the geothermal well 2 and transports it to one of the flow channels of the plate heat exchanger 9 for heat exchange with the water in the other flow channel. After heat exchange and cooling in one flow channel, the 12°C circulating water is injected back into the geothermal well 2 for reheating, and the circulation is repeated. The other flow channel of the plate heat exchanger 9 exchanges heat with one of the flow channels, heating the 8°C water to 15°C, and then enters the evaporator of the second heat pump 3 for heat exchange. After heat exchange and cooling in the evaporator of the second heat pump 3, the 8°C water enters the other flow channel of the plate heat exchanger 9 through the heat pump circulation pump 17 for heat exchange, and a water cycle is formed between the other flow channel of the plate heat exchanger 9 and the evaporator of the second heat pump 3.

[0085] Water supply pipeline and heat supply pipeline: the second stop valve 14 on each heat branch is opened, the first regulating valve 4, the second regulating valve 5 and the third regulating valve 8 are opened, and the system circulation pump 18 is opened; the first heat pump 1 heats the 60°C water provided by the first water supply outlet branch to 75°C, the second heat pump 3 heats the 60°C water provided by the second water supply outlet branch to 75°C, and the third heat pump 6 heats the 60°C water provided by the third water supply outlet branch to 75°C. The water heated by the first heat pump 1, the second heat pump 3 and the third heat pump 6 all enters the heat supply main circuit, and then passes through The opened second stop valves 14 respectively enter one of the flow channels of the dehydration heat exchanger 10, the hot oil heat exchanger 11, the blending heat exchanger 12 and the hot water heat exchanger 13 for heat exchange. The 75°C water is cooled to 60°C after heat exchange. The 60°C water is then transported to the first water supply outlet branch, the second water supply outlet branch and the third water supply outlet branch through the system circulation pump 18, and enter the condensers of the first heat pump 1, the second heat pump 3 and the third heat pump 6 respectively through the opened first regulating valve 4, the second regulating valve 5 and the third regulating valve 8 for heat exchange, forming a water cycle.

[0086] Heat unit:

[0087] For the dehydration heat exchanger 10, the dehydration circulation pump 19 transports the 45°C water-containing crude oil to another flow channel of the dehydration heat exchanger 10 for heat exchange, and heats the water-containing crude oil to 70°C, thereby achieving dehydration of the water-containing crude oil;

[0088] For the hot oil heat exchanger 11, the hot oil circulation pump 20 transports the 43°C crude oil to another flow channel of the hot oil heat exchanger 11 for heat exchange, and heats the low-temperature crude oil to 70°C, thereby achieving heating of the crude oil;

[0089] For the blending heat exchanger 12, the blending circulation pump 21 transports the 42°C oily wastewater to another flow channel of the blending heat exchanger 12 for heat exchange, and heats the low-temperature oily wastewater to 65°C for use;

[0090] For the hot water heat exchanger 13, the heating circulation pump 22 transports the user heating return water at 40°C to another flow channel of the hot water heat exchanger 13 for heat exchange, heats the user heating return water to 65°C and sends it to the user for heating, thereby meeting the heating needs of the heating users; during the heating season, the heating circulation pump 22 and the corresponding second stop valve 14 on the heating branch are both opened; during the non-heating season, the heating circulation pump 22 and the corresponding second stop valve 14 on the heating branch are both closed.

[0091] Benefit Analysis:

[0092] In terms of social benefits, compared with coal-fired boilers, it is estimated that 5,924 tons of standard coal can be saved each year, CO2 emissions can be reduced by about 14,619 tons, and NO x The emissions were reduced by about 220t, and the carbon emission benefits were about 2.2884 million yuan.

[0093] As for economic benefits, assuming that the dehydration, hot oil and blending in the oil field station operate uninterruptedly for 365 days, and the user heating is calculated as 120 days, compared with gas boilers, 7.83 million cubic meters of gas can be saved each year. The heat pump consumes about 14,663,316 KW.h of electricity each year. Compared with gas, it can save about 15.15 million yuan in operating costs.

[0094] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An oilfield wastewater waste heat and geothermal combined heating system, characterized in that: include: The sewage heat exchange unit comprises a first heat pump, wherein the inlet end of the evaporator of the first heat pump is connected to the sewage outlet pipe, the outlet end is connected to the sewage return pipe, the inlet end of the condenser of the first heat pump is connected to the water supply flow path, and the outlet end is connected to the heat supply flow path; A geothermal heat exchange unit, comprising a second heat pump, wherein the inlet end of the evaporator of the second heat pump is connected to the water outlet pipe of the geothermal well, the water outlet end is connected to the return pipe of the geothermal well, the inlet end of the condenser of the second heat pump is connected to the water supply flow path, and the outlet end is connected to the heat supply flow path; and, The heat-using unit comprises at least one heat-using heat exchanger, and the heat supply flow path and the water supply flow path exchange heat at the heat-using heat exchanger.

2. The oilfield wastewater waste heat and geothermal combined heating system according to claim 1 is characterized in that: The water supply flow path includes a water supply trunk and a first water supply lead-out branch and a second water supply lead-out branch both connected to the water supply trunk, the first water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the first heat pump, and the second water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the second heat pump, wherein: The first water supply outlet branch is provided with a first regulating valve; and / or, A second regulating valve is provided on the second water supply outlet branch.

3. The oilfield wastewater waste heat and geothermal combined heating system according to claim 1 is characterized in that: The sewage heat exchange unit also includes a third heat pump, the inlet end of the evaporator of the third heat pump is connected to the outlet end of the evaporator of the first heat pump, and the outlet end is connected to the sewage return pipe, the inlet end of the condenser of the third heat pump is connected to the water supply path, and the outlet end is connected to the heat supply path.

4. The oilfield wastewater waste heat and geothermal combined heating system according to claim 3 is characterized in that: The outlet end of the evaporator of the first heat pump is connected to the sewage return pipe through a first pipe, and the inlet end of the evaporator of the third heat pump is connected to the first pipe through a second pipe. A first stop valve is provided on the first pipe, and the first stop valve is located between the second pipe and the sewage return pipe, so that the outlet end of the evaporator of the first heat pump is connected to the sewage return pipe or to the inlet end of the evaporator of the third heat pump.

5. The oilfield wastewater waste heat and geothermal combined heating system according to claim 3 is characterized in that: The water supply flow path includes a water supply trunk and a first water supply lead-out branch, a second water supply lead-out branch, and a third water supply lead-out branch, all of which are connected to the water supply trunk. The first water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the first heat pump, the second water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the second heat pump, and the third water supply lead-out branch leads the water on the water supply trunk to the inlet end of the condenser of the third heat pump, wherein: The first water supply outlet branch is provided with a first regulating valve; and / or, A second regulating valve is provided on the second water supply outlet branch; and / or, The third water supply outlet branch is provided with a third regulating valve.

6. The oilfield wastewater waste heat and geothermal combined heating system according to claim 1, characterized in that: The geothermal heat exchange unit also includes a plate heat exchanger, which is installed between the geothermal well and the second heat pump. The inlet end of one flow channel of the plate heat exchanger is connected to the outlet pipe of the geothermal well, and the outlet end is connected to the return pipe of the geothermal well. The inlet end of another flow channel of the plate heat exchanger is connected to the outlet end of the evaporator of the second heat pump, and the outlet end is connected to the inlet end of the evaporator of the second heat pump.

7. The oilfield wastewater waste heat and geothermal combined heating system according to claim 1, characterized in that: The geothermal well is transformed from an abandoned oil well.

8. The oilfield wastewater waste heat and geothermal combined heating system according to claim 1, characterized in that: The heat supply flow path includes a heat supply trunk and at least one heat consumption branch both connected to the heat supply trunk, the heat supply trunk is connected to the outlet end of the condenser of the first heat pump and the outlet end of the condenser of the second heat pump, and the heat consumption heat exchanger is arranged on at least one of the heat consumption branches; The water supply flow path includes a water supply trunk and at least one water supply introduction branch connected to the water supply trunk, the water supply trunk is connected to the inlet end of the condenser of the first heat pump and the inlet end of the condenser of the second heat pump, and the heat exchanger is also provided on at least one of the water supply introduction branches; The heat exchanger includes at least one of a dehydration heat exchanger, a hot oil heat exchanger, a blending heat exchanger and a hot water heat exchanger.

9. The oilfield wastewater waste heat and geothermal combined heating system according to claim 8, characterized in that: A second stop valve is provided on the heat-using branch; and / or, The water supply trunk line is provided with a system circulation pump.

10. The oilfield wastewater waste heat and geothermal combined heating system according to claim 8, characterized in that: The dehydration heat exchanger is a shell and tube heat exchanger; and / or, The hot oil heat exchanger is a shell and tube heat exchanger; and / or, The mixing heat exchanger is a shell and tube heat exchanger; and / or, The hot water heat exchanger is a plate heat exchanger.

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