Steam supply system based on coupling energy storage technology

Abstract

The invention provides a steam supply system based on a coupling energy storage technology, and relates to the technical field of engineering thermophysics, the steam supply system comprises a heat supply system and an evaporation system; the heat supply system comprises a high-temperature heat source, a superheater, an evaporator and a preheater which are sequentially connected in series through heat pipes to form a loop. The evaporation system comprises a water source, a preheater, an evaporator and a superheater which are sequentially connected through water pipes, and the superheater is connected with a pipeline leading to an oil reservoir; the heat supply system further comprises a thermochemical heat storage tank and a sensible heat storage tank which are connected with the high-temperature heat source in parallel through heat pipes. The thermochemical storage system and the sensible heat storage system are coupled together, the advantage that sensible heat storage can store and release heat at the low temperature is utilized, heat is provided for the thermochemical storage system at the low temperature, the defect that a low-temperature area cannot be used in thermochemistry is overcome, and the heat storage efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of engineering thermal physics, and in particular to a steam supply system based on coupled energy storage technology. Background Art

[0002] Thermal recovery of heavy oil in oil fields mainly includes steam stimulation, steam flooding, steam-assisted gravity drainage and flooding and drainage composite processes. With the development of oil fields, gravity drainage, as an effective replacement technology for heavy oil development and an effective mobilization technology for super-heavy oil development, will become the main development technology for heavy oil in the future.

[0003] At present, oil fields mainly use natural gas combustion to generate superheated steam for heavy oil thermal recovery, which has high carbon emissions. Under the goal of "double carbon", it has become very necessary to replace the combustion of traditional natural gas with renewable clean energy. There are many projects abroad that use solar thermal to produce steam for heavy oil thermal recovery, and the operation effect is good. However, solar energy is limited by time, resulting in the inability to continuously generate steam for oil field thermal recovery at night when there is no solar radiation. Introducing a heat storage system into a solar thermal system can solve the above problem well. It can store solar energy in the form of thermal energy during the day when there is a surplus of solar energy, and release the stored thermal energy for steam generation at night when there is a shortage of solar energy.

[0004] The Chinese invention patent with publication number CN109442532A discloses a high-temperature phase-change solid heat storage split heat exchange heating steam system, which mainly includes a solid heat storage electric boiler, a fan, an oil-gas heat exchanger, a steam device, an oil-water heat exchanger and a water-water heat exchanger. The invention can prevent the oil-water heat exchanger or the steam device from working in a high-temperature environment of hot air for a long time, thereby extending the service life, and the heat transfer oil in the oil-gas heat exchanger effectively reduces the outlet temperature of the hot air side, can extract more heat from the boiler, and improve the thermoelectric conversion efficiency. The Chinese invention patent with publication number CN113883488A discloses a new type of stepped phase-change heat storage and steam generation system. The system combines a sensible heat storage unit with a latent heat storage unit, wherein the latent heat unit includes multiple heat storage subsystems, further utilizes the heat absorption capacity of the phase change material, and improves the stability of the system, and can also realize the supply of steam with different outlet temperatures and the thermal energy storage of surplus steam. The Chinese invention patent with publication number CN106931657A discloses a solar high-temperature storage and release system based on thermochemical method, including heat transfer fluid supply subsystem, reaction subsystem, heat exchange subsystem, condensation subsystem, water supply system and Rankine steam generator set. The system can meet the needs of energy conservation and emission reduction, provide efficient, stable and high-quality thermal energy for solar thermal power generation, and realize the continuous operation of the thermal power generation system.

[0005] The above patents either use a thermal phase change heat storage system or a single thermochemical energy storage system to achieve steam supply with different outlet temperatures and thermal energy storage of surplus steam and improve system stability. However, the heat storage and release reactions of thermal phase change heat storage technology and thermochemical heat storage technology are greatly affected by temperature and cannot utilize heat energy at lower temperatures. Summary of the invention

[0006] The purpose of the present invention is to provide a steam supply system based on coupled energy storage technology, which couples the thermochemical and sensible heat storage systems together to overcome the disadvantage that thermochemistry cannot use lower temperature areas, improves the efficiency of heat storage, and can continue to supply heat to the steam system for heavy oil thermal recovery at night.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A steam supply system based on coupled energy storage technology includes a heating system and an evaporation system; the evaporation system includes a water source, a preheater, an evaporator and a superheater connected in sequence through water pipes, and the superheater is connected to a pipeline leading to an oil reservoir; the heating system includes a high-temperature heat source and a heat pipe that sequentially connects the high-temperature heat source, the superheater, the evaporator and the preheater in series to form a loop; the heating system also includes a thermochemical heat storage tank and a sensible heat storage tank connected in parallel with the high-temperature heat source through the heat pipe.

[0009] Furthermore: a water treatment device is connected between the water source and the preheater.

[0010] Furthermore: a plurality of heat exchange tubes connected with the heat pipes are distributed in the thermochemical heat storage tank and the sensible heat storage tank, and heat exchange fins are evenly distributed on the heat exchange tubes.

[0011] Furthermore: the thermochemical heat storage tank is filled with thermochemical storage materials and reaction catalysts, and an insulation layer is provided outside the thermochemical heat storage tank.

[0012] Further: the thermochemical storage material is carbonate particles.

[0013] Furthermore: the upper end of the thermochemical heat storage tank is also connected to a gas storage tank through a gas pipeline, and a valve V4 and a turbine are installed on the gas pipeline.

[0014] Furthermore: valves V1, V2, and V3 are installed between the parallel node between the high-temperature heat source and the superheater, and between the high-temperature heat source, the superheater, and the thermochemical heat storage tank, respectively.

[0015] Furthermore: a valve V5 is installed between the thermochemical heat storage tank and the sensible heat storage tank; valves V6 and V7 are installed between the parallel node between the high-temperature heat source and the preheater on the heating system and the sensible heat storage tank and the preheater, respectively.

[0016] Furthermore: it also includes a steam recovery pipeline connected to the oil reservoir, and the steam recovery pipeline is connected to a water source.

[0017] The present invention also provides a heat storage and release method for a steam supply system based on coupled energy storage technology, which includes two processes: heat storage and heat release:

[0018] Heat storage process: During the day, the high-temperature heat source heats the heat transfer fluid, and part of the heat transfer fluid passes through the steam generation system to generate steam for heavy oil thermal recovery; the excess heat transfer fluid first enters the thermochemical heat storage system, where the high-temperature heat transfer fluid heats the heat storage material, causing it to absorb heat and decompose into metal oxides and CO 2 The turbine will decompose the CO 2 The compressed gas is stored in a gas storage tank to achieve thermochemical heat storage. After the temperature of the heat transfer fluid drops, it enters the sensible heat storage system and transfers the waste heat to the sensible heat storage material for storage.

[0019] Heat release process: At night, the heat transfer fluid first obtains a certain amount of heat from the sensible heat storage material; then the heated heat transfer fluid enters the thermochemical storage system. After heating, CO 2 Under the action of the catalyst, an exothermic reaction occurs with the heat storage material, further increasing the temperature of the heat transfer fluid; the high-temperature heat transfer fluid provides heat to water in the preheater, evaporator and superheater in the steam generation system, generating superheated steam for heavy oil thermal recovery.

[0020] Compared with the original technology, the present invention has the following beneficial effects:

[0021] 1. The present invention couples thermochemical and sensible heat storage systems together, taking advantage of the fact that sensible heat storage can store and release heat at low temperatures. The sensible heat storage tank provides reaction heat for the thermochemical heat storage tank at low temperatures, overcoming the shortcoming that the thermochemical system cannot use lower temperature areas and improving the efficiency of heat storage.

[0022] Second, this system can store excess energy during the day in the form of thermochemical and sensible heat and release it at night to generate steam, continuously supplying superheated steam to the oil field. Compared with traditional steam generation by burning natural gas, it reduces carbon emissions.

[0023] 3. The thermochemical storage system has a larger thermal energy storage density, a longer storage period and smaller heat loss, which reduces the footprint and heat loss of the thermal storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of this system;

[0025] Figure 2 It is a structural schematic diagram of a single heat exchange tube;

[0026] In the figure:

[0027] 1.1. Water source; 1.2. Preheater; 1.3. Evaporator; 1.4. Superheater; 1.5. Water treatment device; 2.1. High-temperature heat source; 2.2. Thermochemical heat storage tank; 2.3. Sensible heat storage tank; 3. Heat exchange tube; 3.1. Heat exchange fin; 4. Oil reservoir; 5. Gas gathering hood; 6. Turbine; 7. Gas storage tank. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0030] A steam supply system based on coupled energy storage technology includes a heating system and an evaporation system; the evaporation system includes a water source 1.1, a preheater 1.2, an evaporator 1.3 and a superheater 1.4 connected in sequence through water pipes, and the superheater 1.4 is connected to a pipeline leading to an oil reservoir 4; the heating system includes a high-temperature heat source 2.1 and a heat pipe that sequentially connects the high-temperature heat source 2.1, the superheater 1.4, the evaporator 1.3 and the preheater 1.2 in series to form a loop; the heating system also includes a thermochemical heat storage tank 2.2 and a sensible heat storage tank connected in parallel with the high-temperature heat source 2.1 through the heat pipe. A water treatment device 1.5 is also connected between the water source 1.1 and the preheater 1.2. The oil reservoir 4 is also connected to a steam recovery pipeline, and the steam recovery pipeline is connected to the water source 1.1.

[0031] The thermochemical heat storage tank 2.2 is filled with a thermochemical storage material and a reaction catalyst. The thermochemical storage material is carbonate particles MgCO 3 The reaction catalyst is KNO 3 or NaNO 3. The parallel node between the high-temperature heat source 2.1 and the superheater 1.4 in the heating system is respectively equipped with valves V1, V2, and V3 between the high-temperature heat source 2.1, the superheater 1.4, and the thermochemical heat storage tank 2.2. A valve V5 is installed between the thermochemical heat storage tank 2.2 and the sensible heat storage pipe; the parallel node between the high-temperature heat source 2.1 and the preheater 1.2 is respectively equipped with valves V6 and V7 between the sensible heat storage tank and the preheater 1.2. A gas gathering hood 5 is installed at the upper end of the thermochemical heat storage tank 2.2, and the gas gathering hood 5 is connected to a gas storage tank 7 through a gas transmission pipeline, and a valve V4 and a turbine 6 are installed on the gas transmission pipeline.

[0032] A number of heat exchange tubes 3 connected to the heat pipes are distributed in the thermochemical heat storage tank 2.2 and the sensible heat storage tank 2.3. Heat exchange fins 3.1 are evenly distributed on the heat exchange tubes 3 to enhance the heat transfer between the heat transfer fluid and the thermochemical storage material. An insulation layer is provided outside the thermochemical heat storage tank 2.2 to reduce the heat loss of the high-temperature heat storage material.

[0033] The present invention also provides a heat storage and release method for a steam supply system based on coupled energy storage technology, which includes two processes: heat storage and heat release:

[0034] Heat storage process: During the day, the high-temperature heat source heats the heat transfer fluid, and part of the heat transfer fluid passes through the steam generation system to generate steam for heavy oil thermal recovery; the excess heat transfer fluid first enters the thermochemical heat storage system, where the high-temperature heat transfer fluid heats the heat storage material, causing it to absorb heat and decompose into metal oxides and CO 2 The turbine will decompose the CO 2 The compressed gas is stored in a gas storage tank to achieve thermochemical heat storage. After the temperature of the heat transfer fluid drops, it enters the sensible heat storage system and transfers the waste heat to the sensible heat storage material for storage.

[0035] Heat release process: At night, the heat transfer fluid first obtains a certain amount of heat from the sensible heat storage material; then the heated heat transfer fluid enters the thermochemical storage system. After heating, CO 2 Under the action of the catalyst, an exothermic reaction occurs with the heat storage material, further increasing the temperature of the heat transfer fluid; the high-temperature heat transfer fluid provides heat to water in the preheater, evaporator and superheater in the steam generation system, generating superheated steam to supply the heavy oil thermal recovery

[0036] The working principle of this system is as follows: It includes two processes: heat storage and heat release:

[0037] Heat storage process: During the day, the high-temperature heat source 2.1 heats the heat transfer fluid passing through it, and opens and adjusts valves V1, V2 and V3 to control the flow of the heat transfer fluid. Part of the heat transfer fluid passes through the superheater 1.4, evaporator 1.3 and preheater 1.2 in turn, and then returns to the high-temperature heat source 2.1 for further heating. The water from the water treatment device 1.5 passes through the preheater 1.2, evaporator 1.3 and superheater 1.4 in turn to generate superheated steam that is introduced into the oil well to drive the heavy oil. While ensuring sufficient steam, the excess heat transfer fluid is input into the thermochemical storage tank 2.2 or the sensible heat storage tank 2.3 for heat storage. The high-temperature heat transfer fluid heats the heat storage material, such as MgCO 3 , causing it to decompose endothermically into metal oxides and CO 2 At this time, valve V4 is opened and turbine 6 is started, which decomposes the CO 2 The compressed gas is stored in the gas storage tank 7 to realize thermochemical heat storage. The heat exchange fins 3.1 evenly distributed on the heat exchange tube 3 strengthen the heat transfer between the heat transfer fluid and the material in the thermochemical storage tank 2.2. The decomposed gas is stored in the thermochemical storage tank 2.2 material gas storage tank 7 through the turbine 6. The heat transfer fluid continues to flow into the sensible heat storage tank 2.3 to transfer the remaining heat to the sensible heat material and then returns to the high-temperature heat source 2.1 through the valve V6 for continued heating.

[0038] Heat release process: At night, valves V2, V3, V4, V5, V6 and V7 are opened, valve V1 is closed, and the low-temperature heat transfer fluid passes through the sensible heat storage tank 2.3 in turn, obtaining a certain amount of heat from the sensible heat storage material; then it enters the thermochemical storage tank 2.2 system. The heat storage material in the thermochemical heat storage tank 2.2 contacts the preheated heat transfer fluid and the CO from the gas storage tank 7. 2 Combined with heat release, the temperature of the heat transfer fluid is further heated to 350-430°C. The high-temperature heat transfer fluid then enters the superheater 1.4, evaporator 1.3 and preheater 1.2 in sequence to transfer heat to the normal temperature water from the water treatment device 1.5, so that it reaches 350-400°C superheated steam for driving heavy oil.

[0039] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A steam supply system based on coupled energy storage technology, characterized in that: Including heating system and evaporation system; The evaporation system comprises a water source, a preheater, an evaporator and a superheater connected in sequence through water pipes, and the superheater is connected to a pipeline leading to the oil reservoir; The heating system includes a high-temperature heat source and a heat pipe that sequentially connects the high-temperature heat source, a superheater, an evaporator and a preheater in series to form a loop; the heating system also includes a thermochemical heat storage tank and a sensible heat storage tank that are connected in parallel with the high-temperature heat source through the heat pipe.

2. A steam supply system based on coupled energy storage technology according to claim 1, characterized in that: A water treatment device is also connected between the water source and the preheater.

3. The steam supply system based on coupled energy storage technology according to claim 1 is characterized in that: A plurality of heat exchange tubes connected with the heat pipes are distributed in the thermochemical heat storage tank and the sensible heat storage tank, and heat exchange fins are evenly distributed on the heat exchange tubes.

4. The steam supply system based on coupled energy storage technology according to claim 1 is characterized in that: The thermochemical heat storage tank is filled with thermochemical storage materials and reaction catalysts, and an insulation layer is arranged outside the thermochemical heat storage tank.

5. A steam supply system based on coupled energy storage technology according to claim 4, characterized in that: The thermochemical storage material is carbonate particles.

6. The steam supply system based on coupled energy storage technology according to claim 1, characterized in that: The upper end of the thermochemical heat storage tank is also connected to a gas storage tank through a gas pipeline, and a valve V4 and a turbine are installed on the gas pipeline.

7. The steam supply system based on coupled energy storage technology according to claim 1, characterized in that: Valves V1, V2, and V3 are installed between the parallel node between the high-temperature heat source and the superheater, and between the high-temperature heat source, the superheater, and the thermochemical heat storage tank, respectively.

8. The steam supply system based on coupled energy storage technology according to claim 7 is characterized in that: A valve V5 is installed between the thermochemical heat storage tank and the sensible heat storage pipe; valves V6 and V7 are installed between the parallel node between the high-temperature heat source and the preheater on the heating system and the sensible heat storage tank and the preheater, respectively.

9. The steam supply system based on coupled energy storage technology according to claim 1, characterized in that: It also includes a steam recovery pipeline connected to the oil reservoir, and the steam recovery pipeline is connected to a water source.

10. The heat storage and release method for a steam supply system based on coupled energy storage technology according to any one of claims 1 to 9, characterized in that: It includes two processes: heat storage and heat release: Heat storage process: During the day, the high-temperature heat source heats the heat transfer fluid, and part of the heat transfer fluid passes through the steam generation system to generate steam for heavy oil thermal recovery; the excess heat transfer fluid first enters the thermochemical heat storage system, and the high-temperature heat transfer fluid heats the heat storage material, causing it to absorb heat and decompose into metal oxides and CO2; the turbine compresses the CO2 produced by the decomposition and stores it in the gas storage tank to achieve thermochemical heat storage; after the temperature of the heat transfer fluid drops, it enters the sensible heat storage system and transfers the residual heat to the sensible heat storage material for storage; Heat release process: At night, the heat transfer fluid first obtains a certain amount of heat from the sensible heat storage material; then the heated heat transfer fluid enters the thermochemical storage system. After heating, CO2 reacts with the heat storage material under the action of the catalyst to further increase the temperature of the heat transfer fluid; The high-temperature heat transfer fluid provides heat to water in the preheater, evaporator and superheater in the steam generation system, generating superheated steam for heavy oil thermal recovery.

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