Power generation and data processing center cooling combined system for LNG (Liquefied Natural Gas) cold energy recovery
Through the combination of Rankine circulation system and multi-stage cooling unit, the problem of LNG cold energy narrow temperature zone utilization and regional mismatch is solved, and the cascade utilization and efficient transportation of cold volume are achieved, and the cold energy utilization rate and system efficiency are improved.
Patent Information
- Application Number
- CN202411510867.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2024-12-10
AI Technical Summary
The existing LNG cold energy recycling methods can only utilize cold energy in narrow temperature zones, and the regional mismatch between the LNG receiving station and the data processing center location makes it difficult to utilize the cold volume, and LNG cold energy cannot be fully utilized.
The Rankine circulation system is used to combine the first-stage or multi-stage cooling unit and the direct expansion unit to reduce the heat exchange temperature difference through the Rankine circulation recycle, realize the cascade utilization of cold energy, and optimize the temperature gradient through the seawater preheater to achieve the cooling capacity. storage and transport to the data processing center.
It improves the utilization rate of cold energy, realizes flexible transportation and storage of cold volume, reduces irreversible losses, improves system efficiency, and promotes the wider temperature zone utilization of LNG cold energy.
Smart Images
Figure CN119102815A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a combined system for power generation and cooling of an LNG data processing center for recovering LNG cold energy, and belongs to the technical field of waste energy recovery. Background Art
[0002] As a clean fossil energy, natural gas has become a very important energy source in the world and plays an important role in peak load regulation. In order to facilitate transportation and storage, natural gas is usually compressed and cooled into liquefied natural gas (LNG). As an ultra-low temperature liquid natural gas, LNG usually has a temperature as low as -162°C. It releases about 830kJ / kg of energy during the gasification process under normal pressure, which contains a large amount of cold energy. The existing recycling and utilization methods of LNG cold energy adopt power generation, light hydrocarbon separation, low-temperature crushing and other methods, but no matter which method is used, only cold energy in a narrow temperature range can be used, that is, a single utilization method cannot fully utilize LNG cold energy. On the other hand, with the increasing demand for AI technology, the power consumption and refrigeration demand of LNG data processing centers are also increasing. By certain technical means, the LNG cold energy can be recycled and used for cooling the LNG data processing center, which will save considerable energy consumption and promote carbon emission reduction of the LNG data processing center. However, since there is often a geographical mismatch between the locations of LNG receiving stations and LNG data processing centers, how to use LNG cold energy for cooling the LNG data processing center needs to be further solved. Summary of the invention
[0003] The technical problem to be solved by the present invention is: to achieve the recycling and utilization of LNG in a wider temperature range, improve the utilization rate of cold energy, and solve the problem of difficulty in utilizing cold energy caused by the geographical mismatch between the location of the LNG data processing center and the location of the LNG receiving station.
[0004] In order to solve the above technical problems, the present invention provides a combined system for power generation and data processing center cooling for LNG cold energy recovery, including a power generation recovery unit, which utilizes a Rankine cycle system to recover input LNG cold energy and uses it for power generation; After the low-temperature LNG is used for power generation by the power generation recovery unit, it enters the primary or multi-stage cold storage unit to cool the cold storage medium; After being heated by the cold storage unit, the LNG enters the direct expansion unit to expand and generate electricity; The cooled low-temperature cold storage medium is packaged in a transport delivery unit and transported to users, while the used cold storage medium is recovered, wherein the users include an LNG data processing center.
[0005] The aforementioned combined system for power generation and data processing center cooling for LNG cold energy recovery, in the power generation recovery unit, uses seawater to heat the circulating working fluid into a gaseous state in a seawater heater, and then the high-temperature gaseous working fluid expands in the Rankine cycle working fluid turbine and drives the turbine blades to rotate to generate electricity, and then passes through the hot side of the Rankine cycle regenerator and the Rankine cycle condenser in turn, and is cooled into a liquid state by LNG, and then is re-sent to the cold side of the Rankine cycle regenerator and the seawater heater by the Rankine cycle working fluid pump.
[0006] In the aforementioned combined system for cooling power generation and data processing centers for LNG cold energy recovery, the freezing point of the circulating working fluid used in the power generation recovery unit is not higher than -162°C at normal pressure, and the condensation temperature at normal pressure is lower than -40°C.
[0007] In the aforementioned combined system for power generation and data processing center cooling using LNG cold energy recovery, the circulating working fluid is a mixture of any one or more of propane, ethane, propylene, and ethylene in a set ratio.
[0008] In the aforementioned combined system for power generation and data processing center cooling using LNG cold energy recovery, the Rankine cycle regenerator has the heat measuring fluid being the fluid at the end outlet of the Rankine cycle working fluid turbine, or the fluid that has not yet been fully expanded and is drawn out from an appropriate portion of the Rankine cycle working fluid turbine.
[0009] The aforementioned combined system for power generation and data processing center cooling for LNG cold energy recovery, in the power generation recovery unit, the number of stages of the organic Rankine cycle is single-stage or multi-stage, and multi-stage means that multiple Rankine cycle systems are arranged in the flow direction of the LNG stream, and the multiple Rankine cycle systems use the same working fluid and different condensation pressures; or multiple Rankine cycle systems use different working fluids, and the condensation pressures are all normal pressure, and multiple Rankine cycle systems form different condensation temperatures to achieve cascade utilization.
[0010] The aforementioned combined system for cooling power generation and data processing centers for LNG cold energy recovery, the cold storage unit includes a first-stage cold storage unit and a second-stage cold storage unit, in the first-stage cold storage unit, uncooled liquid propylene glycol is pumped into the propylene glycol cooler by the propylene glycol medium pump, in the propylene glycol cooler, LNG cools the propylene glycol, and then the cooled propylene glycol is stored in the propylene glycol storage tank for standby use; Afterwards, LNG enters the second-stage cold storage unit, in which the uncooled liquid ethylene glycol is pumped into the ethylene glycol cooler by the ethylene glycol medium pump, in which the LNG cools the ethylene glycol, and then the cooled ethylene glycol is stored in the ethylene glycol storage tank for standby use.
[0011] In the aforementioned combined system for power generation and data processing center cooling for LNG cold energy recovery, the melting points of the refrigerants at normal pressure in the first and second cold storage units are respectively -60°C and -12.6°C, forming a temperature gradient.
[0012] The aforementioned combined system for cooling power generation and data processing centers for LNG cold energy recovery monitors the LNG temperature before the LNG enters the propylene glycol cooler and the ethylene glycol cooler. If the corresponding temperature is lower than the melting point of propylene glycol or ethylene glycol, seawater preheater I and seawater preheater II are used for preheating respectively until the LNG temperature at the monitoring point is greater than the corresponding melting point.
[0013] In the above-mentioned combined system for power generation and data processing center cooling for LNG cold energy recovery, in the direct expansion unit, the LNG heated by the power generation recovery unit and the cold storage unit is sent to the seawater preheater III for further heating, and then enters the LNG turbine for expansion and drives the turbine blades to rotate to generate electricity; In the direct expansion unit, the LNG heated by the cold storage unit is directly sent to the LNG turbine for expansion and work, or a seawater preheater III is added to the LNG outlet of the ethylene glycol cooler to further increase the LNG temperature before sending it to the LNG turbine for expansion and work.
[0014] The beneficial effects achieved by the present invention are as follows: the present invention greatly reduces the heat exchange temperature difference, reduces the irreversible loss, and improves the exergy efficiency of the system by setting up the regenerator in the Rankine cycle; the LNG cold energy is recovered in different temperature zones by using the LNG cold energy in a cascade manner, and the dual output of power generation and cold energy is achieved at the same time. The cold energy can be stored in the cold storage module in time and can be flexibly transported to the LNG data processing center or other places where cold energy is required. The cold energy can even be stored in a capsule-shaped phase change material for easy sale, which promotes the popularization and utilization of LNG cold energy, and can realize the utilization of LNG cold energy in a wider temperature zone, thereby achieving a higher cold energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a system schematic diagram of Example 1 of the present invention.
[0016] Figure markings: 1-LNG pump; 2-Rankine cycle working fluid pump; 3-Rankine cycle regenerator; 4-seawater heater; 5-Rankine cycle working fluid turbine; 6-propylene glycol medium pump; 7-propylene glycol storage tank; 8-ethylene glycol medium pump; 9-ethylene glycol storage tank; 10-transport vehicle; 11-LNG data processing center; 12-Rankine cycle condenser; 13-propylene glycol cooler; 14-ethylene glycol cooler; 15-LNG turbine; 16-seawater preheater I; 17-seawater preheater II; 18-seawater preheater III; 19-post-heater; 100-power generation recovery unit; 200-first stage cold storage unit; 300-second stage cold storage unit; 400-direct expansion unit; 500-transport transfer unit. DETAILED DESCRIPTION
[0017] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings. Example
[0018] like Figure 1 As shown, this embodiment provides a combined system for power generation and data processing center cooling for LNG cold energy recovery, including a power generation recovery unit 100, which utilizes a Rankine cycle system to recover input LNG cold energy and uses it for power generation; After the low-temperature LNG is used for power generation by the power generation recovery unit, it enters the primary or multi-stage cold storage unit to cool the cold storage medium; The LNG heated by the cold storage unit enters the direct expansion unit 400 to expand and generate electrical energy; The cooled low-temperature cold storage medium is packaged in the transport delivery unit 500 and transported to users, while the used cold storage medium is recovered. The users include an LNG data processing center.
[0019] For the LNG cold energy in the ultra-low temperature zone (<-60°C), it first enters the power generation recovery unit. The power generation recovery unit recovers the LNG cold energy based on the principle of organic Rankine cycle and uses it for power generation. The power generation recovery unit includes a Rankine cycle working fluid pump 2, a seawater heater, a Rankine cycle working fluid turbine, a Rankine cycle condenser, and a Rankine cycle regenerator. In the power generation recovery unit, the circulating working fluid is heated into a gaseous state by seawater in the seawater heater 4, and then the high-temperature gaseous working fluid expands in the Rankine cycle working fluid turbine 5 and drives the turbine blades to rotate to generate electricity. After passing through the hot side of the Rankine cycle regenerator 3 and the Rankine cycle condenser 12 in turn, it is cooled into a liquid state by LNG, and then re-sent to the cold side of the Rankine cycle regenerator 3 and the seawater heater 4 by the Rankine cycle working fluid pump 2, so that the power generation cycle can be carried out.
[0020] Through the Rankine cycle regenerator 3, the circulating medium at the turbine outlet enters the hot side of the Rankine cycle regenerator, and the circulating medium before entering the seawater heater enters the cold side of the Rankine cycle regenerator first, and is preheated in advance to reduce the heat exchange temperature difference, thereby reducing the irreversible loss in the heat exchange process and improving the power generation efficiency.
[0021] The low-temperature LNG (<0°C) after power generation first enters the cold storage unit. The cold storage unit includes a first-stage cold storage unit 200 and a second-stage cold storage unit 300. The first-stage cold storage unit includes a propylene glycol medium pump 6, a propylene glycol storage tank 7 and a propylene glycol cooler 13. The uncooled liquid propylene glycol is sent to the propylene glycol cooler 13 by the propylene glycol medium pump 6, and the LNG in the propylene glycol cooler 13 cools the propylene glycol. Then, the cooled propylene glycol is stored in the propylene glycol storage tank for standby use.
[0022] After that, LNG enters the second-stage cold storage unit. The second-stage cold storage unit includes an ethylene glycol medium pump 8, an ethylene glycol storage tank 9 and an ethylene glycol cooler 14. Similar to the first-stage cold storage unit, uncooled liquid ethylene glycol is sent to the ethylene glycol cooler 14 by the ethylene glycol medium pump 8, and the LNG cools the ethylene glycol in the ethylene glycol cooler 14. Then, the cooled ethylene glycol is stored in the ethylene glycol storage tank for standby use.
[0023] In the first-stage cold storage unit and the second-stage cold storage unit, the melting points of the cold storage agents used are respectively -60°C and -12.6°C, both of which are less than 0°C, and have different melting points with a large temperature difference, forming a temperature gradient.
[0024] In this embodiment, the primary cold storage unit uses propylene glycol and the secondary cold storage unit uses ethylene glycol. Before LNG enters the propylene glycol cooler and the ethylene glycol cooler, the LNG temperature is monitored. If the corresponding temperature is lower than the melting point of propylene glycol or ethylene glycol, seawater preheater I 16 and seawater preheater II 17 are used respectively for appropriate preheating until the LNG temperature at the monitoring point is greater than the corresponding melting point.
[0025] The direct expansion unit includes a seawater preheater III 18 and an LNG turbine 15. The LNG heated by the circulating medium, propylene glycol and ethylene glycol in sequence is sent to the seawater preheater III 18 for further heating, and then enters the LNG turbine 15 for expansion and drives the turbine blades to rotate to generate electricity.
[0026] Finally, the expanded LNG is heated to a suitable temperature (>0°C) by seawater in the post-heater 19, becomes natural gas, leaves the LNG receiving terminal and is delivered to specific users.
[0027] In the transport and transfer unit, the cooled low-temperature propylene glycol and ethylene glycol are packaged and transported to the LNG data processing center 11 or other places where cooling is required, and the used high-temperature propylene glycol and ethylene glycol are recovered. The transport vehicle 10 can subpackage and transport the propylene glycol and ethylene glycol in the storage tank to the data cooling center for refrigeration, and return the heated propylene glycol and ethylene glycol coolant. For LNG data processing centers that are relatively close, pipeline transportation can be adopted to transport the cooled propylene glycol and ethylene glycol to the LNG data processing center, and return the heated propylene glycol and ethylene glycol to the cold storage units at various levels.
[0028] Among them, the process of LNG-NG is as follows: LNG sequentially enters the LNG pump 1, the cold side of the Rankine cycle condenser 12 of the power generation recovery unit, the seawater preheater Ⅰ16, the cold side of the propylene glycol cooler 13 of the first-stage cold storage unit, the seawater preheater Ⅱ12, the cold side of the ethylene glycol cooler 14 of the second-stage cold storage unit, the seawater preheater Ⅲ18 of the direct expansion unit, the LNG turbine 15 of the direct expansion unit, and the after-heater 19, and becomes pipeline natural gas and is delivered to designated users.
[0029] The circulating working fluid used in the power generation recovery unit has a freezing point of no higher than -162° C. at normal pressure and a condensation temperature lower than -40° C. The optional scheme of the power generation recovery unit is a single-stage single-propane working fluid Rankine cycle.
[0030] The heat measuring fluid of the Rankine cycle regenerator used in the power generation recovery unit can be the fluid at the end outlet of the Rankine cycle working fluid turbine, or the fluid that has not been fully expanded and led out of the appropriate part of the Rankine cycle working fluid turbine, such as the fluid that has not been fully expanded at the expansion back pressure side close to the Rankine cycle working fluid turbine, where the pressure is 1 / 4 of the total pressure difference before and after expansion. The purpose is to reduce the heat exchange temperature difference and reduce irreversible losses. Example
[0031] In the power generation recovery unit, the circulating working fluid is a mixture of any one or more of ethane, propylene and ethylene in a set ratio.
[0032] Other technical features are the same as those of Example 1. Example
[0033] In the power generation recovery unit, the number of stages of the organic Rankine cycle is single or multi-stage. Multi-stage means that multiple Rankine cycle systems are set in the flow direction of the LNG stream. The multiple Rankine cycle systems can use the same working fluid and different condensation pressures; or the multiple Rankine cycle systems use different working fluids and the condensation pressures are all normal pressure. Multiple Rankine cycle systems form different condensation temperatures to achieve cascade utilization.
[0034] Other technical features are the same as those of Example 1. Example
[0035] The first-stage cold storage unit and the second-stage cold storage unit adopt phase change cold storage. When water is used as the coolant and phase change cold storage is performed in the form of solid ice, the solid ice is directly transported to the LNG data processing center in blocks by a transport vehicle and used as chilled water without recycling. If it is summer, a large amount of solid ice can also be sold directly on the market, which is economical and has high flexibility. Example
[0036] In the direct expansion unit, the LNG heated by propylene glycol and ethylene glycol can be directly sent to the LNG turbine for expansion and work. Figure 1 A seawater preheater III 18 is added to the LNG outlet of the glycol cooler to further increase the LNG temperature before it is sent into the LNG turbine for expansion and work.
[0037] The above implementation modes are not limitations of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the scope of the technical solution of the present invention also belong to the protection scope of the present invention.
Claims
1. A combined system for power generation and data processing center cooling for LNG cold energy recovery, characterized in that: It includes a power generation recovery unit, which utilizes the Rankine cycle system to recover the cold energy of the input LNG and use it for power generation; After the low-temperature LNG is used for power generation by the power generation recovery unit, it enters the primary or multi-stage cold storage unit to cool the cold storage medium; After being heated by the cold storage unit, the LNG enters the direct expansion unit to expand and generate electricity; The cooled low-temperature cold storage medium is packaged in a transport delivery unit and transported to users, while the used cold storage medium is recovered, wherein the users include an LNG data processing center.
2. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 1 is characterized in that: In the power generation recovery unit, the circulating working fluid is heated into a gaseous state by seawater in the seawater heater, and then the high-temperature gaseous working fluid expands in the Rankine cycle working fluid turbine and drives the turbine blades to rotate to generate electricity. After passing through the hot side of the Rankine cycle regenerator and the Rankine cycle condenser in sequence, it is cooled into a liquid state by LNG and then re-sent to the cold side of the Rankine cycle regenerator and the seawater heater by the Rankine cycle working fluid pump.
3. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 2 is characterized in that: The freezing point of the circulating working fluid used in the power generation recovery unit is not higher than -162°C at normal pressure, and the condensation temperature at normal pressure is lower than -40°C.
4. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 2 is characterized in that: The circulating working fluid is a mixture of any one or more of propane, ethane, propylene and ethylene in a set ratio.
5. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 2 is characterized in that: In the Rankine cycle regenerator, the heat measuring fluid is the fluid at the end outlet of the Rankine cycle working fluid turbine, or the fluid that has not been fully expanded and is led out from an appropriate part of the Rankine cycle working fluid turbine.
6. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 1, characterized in that: In the power generation recovery unit, the number of Rankine cycle stages is single or multi-stage. Multi-stage means that multiple Rankine cycle systems are arranged in the flow direction of the LNG stream, and the multiple Rankine cycle systems use the same working fluid and different condensation pressures; or multiple Rankine cycle systems use different working fluids, and the condensation pressures are all normal pressure. Multiple Rankine cycle systems form different condensation temperatures to achieve cascade utilization.
7. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 1, characterized in that: The cold storage unit includes a first-stage cold storage unit and a second-stage cold storage unit. In the first-stage cold storage unit, uncooled liquid propylene glycol is pumped into the propylene glycol cooler by the propylene glycol medium pump, and LNG cools the propylene glycol in the propylene glycol cooler. Then, the cooled propylene glycol is stored in the propylene glycol storage tank for standby use. Afterwards, LNG enters the second-stage cold storage unit, in which the uncooled liquid ethylene glycol is pumped into the ethylene glycol cooler by the ethylene glycol medium pump, in which the LNG cools the ethylene glycol, and then the cooled ethylene glycol is stored in the ethylene glycol storage tank for standby use.
8. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 7, characterized in that: In the first-stage cold storage unit and the second-stage cold storage unit, the melting points of the cold storage agents at normal pressure are respectively -60°C and -12.6°C, forming a temperature gradient.
9. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 7, characterized in that: Before LNG enters the propylene glycol cooler and the ethylene glycol cooler, the LNG temperature is monitored. If the corresponding temperature is lower than the melting point of propylene glycol or ethylene glycol, seawater preheater I and seawater preheater II are used for preheating respectively until the LNG temperature at the monitoring point is greater than the corresponding melting point.
10. The combined system for power generation and data processing center cooling for LNG cold energy recovery according to claim 1, characterized in that: In the direct expansion unit, the LNG heated by the power generation recovery unit and the cold storage unit is sent to the seawater preheater III for further heating, and then enters the LNG turbine for expansion and drives the turbine blades to rotate to generate electricity; In the direct expansion unit, the LNG heated by the cold storage unit is directly sent to the LNG turbine for expansion and work, or a seawater preheater III is added to the LNG outlet of the ethylene glycol cooler to further increase the LNG temperature before sending it to the LNG turbine for expansion and work.