Carbon dioxide heat pump and molten salt heat storage system for converting low-grade heat into high-grade heat
By recovering and converting low-grade heat from the atmospheric and vacuum distillation unit of the oilfield refinery using carbon dioxide heat pumps and molten salt thermal storage systems, the problem of insufficient utilization of low-grade heat has been solved, and high-grade heat generation and energy-saving and emission-reduction effects have been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING SHOUHANG IHW RESOURCES SAVING TECH CO LTD
- Filing Date
- 2025-06-06
- Publication Date
- 2026-06-09
AI Technical Summary
The low-grade heat in the atmospheric and vacuum distillation unit of the oilfield refinery cannot be effectively utilized, resulting in a large amount of low-grade heat loss and high carbon emissions. At the same time, the gas furnace consumes a large amount of gas to heat the materials, increasing energy costs and carbon emissions.
A carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat is used. Through carbon dioxide circulation, water circulation and molten salt circulation subsystems, the low-grade heat of the material to be cooled is recovered and converted. By using carbon dioxide heat pump and molten salt thermal storage technology, the effective utilization and conversion of heat is achieved.
It achieves efficient recovery and utilization of low-grade heat, reduces circulating water and gas consumption, reduces carbon emissions, saves electricity costs, and improves economic efficiency.
Smart Images
Figure CN224340382U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of energy recovery technology in petroleum refineries, and in particular to a carbon dioxide heat pump and molten salt heat storage system that converts low-grade heat into high-grade heat. Background Technology
[0002] The atmospheric and vacuum distillation unit in an oilfield refinery requires cooling of various materials, including overhead oil and gas, atmospheric line 1, atmospheric line 2, atmospheric line 3, vacuum line 1, vacuum line 2, and vacuum line 3. Overhead oil and gas are typically cooled using shell-and-tube circulating water heat exchangers and electric air coolers. Other materials are cooled using shell-and-tube circulating water heat exchangers. The material temperature in the atmospheric and vacuum distillation unit is usually below 100°C, representing low-grade heat, which is directly lost to the atmosphere. Simultaneously, the heat required for heating the materials in the atmospheric and vacuum distillation unit is supplied by gas furnaces consuming gas from the refinery's gas pipeline network, with heating temperatures typically between 300 and 400°C.
[0003] The large amount of low-grade heat generated by the material to be cooled cannot be utilized and will consume a large amount of circulating water. In addition, the gas furnace consumes a large amount of gas to heat the material to be heated, resulting in high carbon emissions.
[0004] For the reasons mentioned above, there is a need for a carbon dioxide heat pump and a molten salt thermal storage system that converts low-grade heat into high-grade heat to recover and utilize the low-grade heat of the materials to be cooled in atmospheric and vacuum distillation units. Utility Model Content
[0005] The purpose of this invention is to provide a carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat. This system utilizes a carbon dioxide heat pump to recover and utilize the low-grade heat of the material to be cooled, thereby reducing carbon emissions, saving electricity costs, and increasing profits.
[0006] To achieve the above objectives, this utility model provides the following technical solution:
[0007] A carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat into high-grade heat includes a carbon dioxide circulation subsystem, a water circulation subsystem, and a molten salt circulation subsystem. The carbon dioxide circulation subsystem includes a first heat exchanger, a regenerator, a compressor, a second heat exchanger, and an expander, all connected sequentially. The water circulation subsystem includes a cold water tank, a material cooler, and a hot water tank, all connected sequentially, with the material to be cooled passing through the material cooler. The molten salt circulation subsystem includes a low-temperature molten salt tank, a high-temperature molten salt tank, and a material heater, all connected sequentially, with the low-temperature molten salt tank, the second heat exchanger, the high-temperature molten salt tank, the material heater, and the low-temperature molten salt tank passing through the material heater.
[0008] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat into high-grade heat, a first water pump is installed on the pipeline between the cold water tank and the material cooler.
[0009] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat, a second water pump is installed on the pipeline between the hot water tank and the first heat exchanger.
[0010] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat, the outlet temperature of the compressor is 300℃~400℃.
[0011] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat, the water circulation subsystem and the molten salt circulation subsystem operate continuously without interruption, while the carbon dioxide circulation subsystem operates during off-peak or green electricity periods.
[0012] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat, the molten salt circulation subsystem also includes a gas furnace. When the molten salt level in the high-temperature molten salt tank is lower than the set value of 1m, the gas furnace is triggered to provide supplemental heating.
[0013] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat, the molten salt circulating in the molten salt circulation subsystem is a binary or ternary salt.
[0014] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat into high-grade heat, a first molten salt pump is installed on the pipeline between the low-temperature molten salt tank and the second heat exchanger.
[0015] Furthermore, in the aforementioned carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat into high-grade heat, a second molten salt pump is installed on the pipeline between the high-temperature molten salt tank and the material heater.
[0016] Analysis reveals that this utility model discloses a carbon dioxide heat pump and molten salt thermal storage system that converts low-grade heat into high-grade heat. This system utilizes a carbon dioxide heat pump to recover and utilize the low-grade heat of the material to be cooled, converting it into high-grade heat to heat the material, thus achieving heat utilization and conversion. The decoupled operation of the carbon dioxide heat pump and the gas furnace for heating the material saves electricity costs and increases profits. By recovering and utilizing the low-grade heat of the material to be cooled, the consumption of circulating water is reduced, and gas can be used as a substitute, reducing carbon emissions. The carbon dioxide heat pump operates during off-peak or green electricity periods, saving electricity costs and increasing profits. Attached Figure Description
[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. Wherein:
[0018] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model.
[0019] Explanation of reference numerals in the attached drawings: 1 First heat exchanger; 2 Regenerator; 3 Compressor; 4 Second heat exchanger; 5 Expander; 6 Cold water tank; 7 First water pump; 8 Material cooler; 9 Hot water tank; 10 Second water pump; 11 Low-temperature molten salt tank; 12 First molten salt pump; 13 High-temperature molten salt tank; 14 Second molten salt pump; 15 Material heater. Detailed Implementation
[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation of the present invention and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present invention encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.
[0021] In the description of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and do not require that this utility model be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. The terms "connected," "linked," and "set up" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.
[0022] The accompanying drawings illustrate one or more examples of the present invention. The detailed description uses numerals and letters to refer to features in the drawings. Similar or analogous reference numerals in the drawings and description have been used to refer to similar or analogous parts of the present invention. As used herein, the terms “first,” “second,” and “third,” etc., are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.
[0023] like Figure 1 As shown in the embodiment of this utility model, a carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat into high-grade heat are provided, including a carbon dioxide circulation subsystem, a water circulation subsystem, and a molten salt circulation subsystem. The carbon dioxide circulation subsystem includes a first heat exchanger 1, a regenerator 2, a compressor 3, a second heat exchanger 4, and an expander 5, which are sequentially connected. The water circulation subsystem includes a cold water tank 6, a material cooler 8, and a hot water tank 9, which are sequentially connected, and the material to be cooled passes through the material cooler 8. The molten salt circulation subsystem includes a low-temperature molten salt tank 11, a high-temperature molten salt tank 13, and a material heater 15, which are sequentially connected, and the material to be heated passes through the material heater 15. This system utilizes a carbon dioxide heat pump in a carbon dioxide circulation subsystem to recover and utilize the low-grade heat of the material to be cooled, thereby achieving heat utilization and conversion. At the same time, it reduces gas consumption, lowers carbon emissions, and saves costs.
[0024] Furthermore, a first water pump 7 is installed on the pipeline between the cold water tank 6 and the material cooler 8, and a second water pump 10 is installed on the pipeline between the hot water tank 9 and the first heat exchanger 1.
[0025] Furthermore, the outlet temperature of compressor 3 is 300℃~400℃.
[0026] Furthermore, the carbon dioxide recycling subsystem operates during off-peak or green electricity periods, when the material to be heated is heated by a gas furnace. The carbon dioxide heat pump and the gas furnace operate decoupled, saving electricity costs and increasing profits.
[0027] Furthermore, the molten salt circulation subsystem also includes a gas furnace, which triggers reheating when the molten salt level in the high-temperature molten salt tank 13 is lower than the set value of 1m.
[0028] Furthermore, the molten salt circulating in the molten salt circulation subsystem is either a binary salt or a ternary salt. The molten salt is selected according to the operating temperature range of the molten salt circulation subsystem, such as a binary salt (solar salt) or a ternary salt. When the operating temperature range of the molten salt circulation subsystem is 250℃~570℃, a binary salt can be selected, and when the operating temperature range of the molten salt circulation subsystem is 150℃~450℃, a ternary salt can be selected.
[0029] Furthermore, a first molten salt pump 12 is installed on the pipeline between the low-temperature molten salt tank 11 and the second heat exchanger 4, and a second molten salt pump 14 is installed on the pipeline between the high-temperature molten salt tank 13 and the material heater 15.
[0030] The workflow of this system is as follows:
[0031] Water circulation within the water circulation subsystem: Low-temperature water in cold water tank 6 enters material cooler 8 through a low-temperature water pump to exchange heat with the material and cool it. After absorbing the low-grade heat from the material to be cooled, the water enters hot water tank 9, where it stores the low-grade heat. The hot water in hot water tank 9 enters the first heat exchanger 1 through a high-temperature water pump and heats the low-temperature, low-pressure carbon dioxide in the carbon dioxide circulation subsystem. The cooled water returns to cold water tank 6 to repeat the next cycle.
[0032] The carbon dioxide cycle within the carbon dioxide circulation subsystem is as follows: Low-temperature, low-pressure carbon dioxide enters the first heat exchanger 1 to exchange heat with the hot water in the water circulation subsystem, cooling the hot water. The carbon dioxide, heated by absorbing low-grade heat from the water circulation subsystem, enters the regenerator 2. Then, it is compressed by the compressor 3 to a temperature of 300℃~400℃, generating high-temperature, high-pressure carbon dioxide. This high-temperature, high-pressure carbon dioxide enters the second heat exchanger 4 and heats the molten salt in the molten salt circulation subsystem. The cooled carbon dioxide then enters the regenerator 2 again, exchanging heat with the carbon dioxide entering from the first heat exchanger 1. It then enters the expander 5 for further cooling and depressurization, finally returning to the first heat exchanger 1 for the next cycle. The regenerator 2 allows the low-temperature, low-pressure carbon dioxide to further absorb heat from the carbon dioxide returning from the second heat exchanger 4 to the expander 5, improving the efficiency of converting low-grade heat to high-grade heat.
[0033] Molten salt circulation in the molten salt circulation subsystem: The low-temperature molten salt in the low-temperature molten salt tank 11 enters the second heat exchanger 4 via the first molten salt pump 12 to exchange heat with the carbon dioxide in the carbon dioxide circulation subsystem and cool the carbon dioxide. The heated molten salt then enters the high-temperature molten salt tank 13, where it stores high-grade heat. The high-temperature molten salt in the high-temperature molten salt tank 13 enters the material heater 15 via the second molten salt pump 14 to heat the material to be heated. The cooled molten salt returns to the low-temperature molten salt tank 11 to repeat the next cycle. The water circulation subsystem and the molten salt circulation subsystem operate continuously without interruption. The carbon dioxide circulation operates during off-peak or green electricity periods, storing low-grade heat in the hot water tank 9 and high-grade heat in the high-temperature molten salt tank 13, thus realizing the recovery and utilization of low-grade heat from the material to be cooled.
[0034] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:
[0035] A carbon dioxide heat pump and molten salt thermal storage system convert low-grade heat into high-grade heat. This system utilizes a carbon dioxide heat pump to recover and utilize the low-grade heat of the material to be cooled, converting it into high-grade heat to heat the material to be heated, thus achieving heat utilization and conversion. The carbon dioxide heat pump and the gas furnace operate decoupled, saving electricity costs and increasing profits. By recovering and utilizing the low-grade heat of the material, the consumption of circulating water is reduced, and gas can be used as a substitute, reducing carbon emissions. The carbon dioxide heat pump operates during off-peak or green electricity periods, saving electricity costs and increasing profits.
[0036] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat into high-grade heat, characterized in that, It includes a carbon dioxide cycle subsystem, a water cycle subsystem, and a molten salt cycle subsystem, among which, The carbon dioxide cycle subsystem includes a first heat exchanger, a regenerator, a compressor, a second heat exchanger, and an expander, which are connected in sequence. The water circulation subsystem includes a cold water tank, a material cooler, and a hot water tank. The cold water tank, the material cooler, the hot water tank, the first heat exchanger, and the cold water tank are connected in sequence, and the material to be cooled passes through the material cooler. The molten salt circulation subsystem includes a low-temperature molten salt tank, a high-temperature molten salt tank, and a material heater. The low-temperature molten salt tank, the second heat exchanger, the high-temperature molten salt tank, the material heater, and the low-temperature molten salt tank are connected in sequence, and the material to be heated passes through the material heater.
2. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, A first water pump is installed on the pipeline between the cold water tank and the material cooler.
3. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, A second water pump is installed on the pipeline between the hot water tank and the first heat exchanger.
4. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, The compressor has an outlet temperature of 300℃~400℃.
5. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, The water circulation subsystem and the molten salt circulation subsystem operate continuously without interruption, while the carbon dioxide circulation subsystem operates during off-peak or green electricity periods.
6. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, The molten salt circulation subsystem also includes a gas furnace. When the molten salt level in the high-temperature molten salt tank is lower than the set value of 1m, the gas furnace is triggered to replenish heat.
7. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, The molten salt circulating in the molten salt circulation subsystem is a binary salt or a ternary salt.
8. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, A first molten salt pump is installed on the pipeline between the low-temperature molten salt tank and the second heat exchanger.
9. The carbon dioxide heat pump and molten salt thermal storage system for converting low-grade heat to high-grade heat according to claim 1, characterized in that, A second molten salt pump is installed on the pipeline between the high-temperature molten salt tank and the material heater.