CN220415480U - Rankine cycle system for combined use of solar energy and LNG cold energy - Google Patents

Abstract

The utility model relates to a Rankine cycle system for combined use of solar energy and LNG cold energy, which comprises: a Rankine cycle system, a solar heat collection system, a steam turbine, a pump and the like. The LNG is heated twice and then enters the turbine to apply work, the thermal working medium at the outlet of the solar heat collection field is divided into two parts, one part of the thermal working medium transfers heat to the Rankine cycle working medium, the other part of the thermal working medium is used for heating the LNG, the Rankine cycle working medium absorbs heat energy in the thermal working medium at the outlet of the solar heat collection field and then enters the turbine to apply work, and then enters the heat exchanger to exchange heat with the LNG to realize condensation, so that solar heat utilization and LNG cold energy utilization are realized. In conclusion, the whole system realizes gradient utilization of LNG cold energy, utilizes the thermal working medium in the solar heat collection field to heat the Rankine cycle working medium and the LNG, and realizes heat utilization of solar energy.

Description

A Rankine cycle system that combines solar energy and LNG cold energy

Technical field

The utility model belongs to the technical field of LNG cold energy utilization, and particularly relates to a Rankine cycle system that uses solar energy and LNG cold energy together.

Background technique

Natural gas (NG), as a green energy, has been widely used around the world. During ocean transportation, natural gas is first processed by dehydration, desulfurization and low-temperature processes to become liquefied natural gas (LNG) and stored in liquid storage tanks. The general storage conditions of LNG are 162°C and 14MPa. When used, LNG needs to be gasified to normal temperature. During this process, a large amount of cold energy will be released, about 830-860kJ/kg. This part of the cold energy is usually used by seawater in the gasification station. Or air consumption, resulting in energy waste and environmental pollution. If this part of the cold energy is utilized, huge economic benefits can be produced.

At present, the utilization methods of LNG cold energy can be divided into direct utilization, indirect utilization and cascade utilization. Direct utilization includes methods such as air separation, low-temperature power generation and low-temperature cold storage, indirect utilization includes methods such as low-temperature crushing, and cascade utilization is comprehensive use through different temperature sections. The above process can make full use of LNG cold energy. At present, among the LNG cold energy utilization methods, cold energy power generation has many applications and mature technology. Compared with other processes such as air separation and low-temperature cold storage, it occupies a smaller area, generates electricity that can be fed into the power grid, and is not subject to Downstream control. Cold energy power generation methods mainly include natural gas direct expansion, low-temperature Rankine cycle, low-temperature Brayton cycle, multi-stage combined cycle and compound cycle. The direct expansion method cannot fully utilize the low-temperature cold energy of LNG, and the cold energy utilization rate is low; the Brayton cycle method, multi-stage cycle and compound cycle are more complicated in equipment operation or system, and have few practical applications; the low-temperature Rankine cycle method has a simple process , good flexibility, so most cold energy power generation devices adopt this process.

By combining LNG cold energy with Rankine cycle and solar energy, it can not only provide sufficient heat source for the LNG cold energy gasification process, but also utilize solar energy to achieve high-energy complementary utilization of solar energy and LNG cold energy.

Utility model content

The purpose of this utility model is to provide a Rankine cycle system that uses solar energy and LNG cold energy together. It is characterized in that the system mainly includes a Rankine cycle system, a solar heat collection system, a steam turbine, a pump and other parts. The solar heat collection system The thermal working fluid in the system is used as the heat source of the Rankine cycle, and LNG is used as the cold source of the Rankine cycle, realizing the high-energy complementary utilization of solar energy and LNG cold energy.

In order to achieve the above purpose, the present utility model adopts the following technical solutions:

The LNG enters the heat exchanger after being pressurized by the pump to transfer the cold energy to the Rankine cycle working fluid. After releasing part of the cold energy, it enters the heat exchanger to exchange heat with the hot working fluid in the solar collector system and vaporizes to increase temperature. Finally enter the turbine to do work.

The Rankine cycle working fluid is pressurized by a pump and then enters the heat exchanger to absorb the heat of the thermal working fluid in the solar collector system and evaporate, and then enters the turbine to perform work. The working fluid after doing the work enters the heat exchanger to absorb the cold energy of LNG. energy and condenses, and finally enters the pump again to complete the cycle.

The thermal fluid in the solar collector system is heated in the solar collector field and then enters the storage tank. The thermal fluid at the exit of the storage tank is divided into two parts. One part enters the heat exchanger and transfers heat to the Rankine cycle. The gas is then pumped back to the solar collector field to complete the cycle, and part of it enters the heat exchanger to transfer heat to LNG and is pumped back to the solar collector field to complete the cycle.

The beneficial effects of this utility model are:

The utility model proposes a Rankine cycle system that jointly uses solar energy and LNG cold energy, and is a new type of LNG cold energy utilization system. The system consists of Rankine cycle system, solar thermal collection system, steam turbine and pump.

The utility model uses the Rankine cycle to absorb part of the cold energy of LNG, uses solar energy to vaporize and heat the LNG, and then passes it into the turbine to perform work, thereby realizing the cascade utilization of LNG cold energy.

In addition, the thermal working fluid in the solar heat collection system is used as the heat source of the Rankine cycle, and LNG is used as the cold source of the Rankine cycle, realizing the high-energy complementary utilization of solar energy and LNG cold energy.

Description of the drawings

Figure 1 is a schematic structural diagram of a Rankine cycle system that uses solar energy and LNG cold energy together.

In the picture: 1-1# pump; 2-1# heat exchanger; 3-2# heat exchanger; 4-1# turbine; 5-2# pump; 6-3# heat exchanger; 7-2# transparent Flat; 8-Solar collector field; 9-Storage tank; 10-3# pump

Detailed ways

The utility model provides a Rankine cycle system that combines solar energy and LNG cold energy. The working principle of this system will be further described below in conjunction with the accompanying drawings and specific implementations. It should be emphasized that the following description is only exemplary. It is not intended to limit the scope and application of the present invention.

Figure 1 shows a schematic diagram of a Rankine cycle system that uses solar energy and LNG cold energy together. 1# pump 1, 1# heat exchanger 2, 2# heat exchanger 3, 1# turbine 4, 2# pump 5, 3# heat exchanger 6, 2# turbine 7, solar collector field 8, storage Tank 9, 3# pump 10, the characteristic is that the LNG enters the 1# heat exchanger 2 after being pressurized by the 1# pump 1 to transfer the cold energy to the Rankine cycle working fluid, and then enters the 2# heat exchanger after releasing part of the cold energy. Heater 3 exchanges heat with the thermal fluid in the solar thermal collection system and vaporizes and heats up, and finally enters turbine 4 #1 to do work.

The Rankine cycle working fluid is pressurized by the 2# pump 5 and then enters the 3# heat exchanger 6 to absorb the heat of the thermal working fluid in the solar heat collection system and evaporate, and then enters the 2# turbine 7 to perform work. The working fluid after doing the work It enters the 1# heat exchanger 2 to absorb the cold energy of LNG and condenses it, and finally enters the 2# pump 5 again to complete the cycle.

The thermal fluid in the solar collector system is heated in the solar collector field 8 and then enters the storage tank 9. The thermal fluid at the exit of the storage tank is divided into two parts, and one part enters the 3# heat exchanger 6 to transfer heat. After being supplied to the Rankine cycle, the working fluid passes through the 3# pump 10 and returns to the solar collector field 8 to complete the cycle. Part of it enters the 2# heat exchanger 3 to transfer heat to LNG and then returns to the solar collector field 8 through the 3# pump 10. Complete the cycle.

The above are only preferred specific implementations of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person familiar with the technical field can easily imagine that within the technical scope disclosed by the present utility model, Any changes or replacements shall be covered by the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the claims.

Claims (5)

1. A Rankine cycle system that uses solar energy and LNG cold energy together, mainly including 1# pump (1), 1# heat exchanger (2), 2# heat exchanger (3), 1# turbine (4 ), 2# pump (5), 3# heat exchanger (6), 2# turbine (7), solar collector field (8), storage tank (9), 3# pump (10), which are characterized by: LNG is pressurized by the 1# pump (1) and then passes through the 1# heat exchanger (2) and the 2# heat exchanger (3) for gasification and temperature rise, and then enters the 1# turbine (4) to do work; solar collector field (8) is connected to the storage tank (9); the thermal fluid at the outlet of the storage tank (9) is divided into two streams, one stream passes through the 3# heat exchanger (6) and the 3# pump (10) in sequence and then returns to the solar heat collection The cycle is completed in the field (8), and one stream passes through the 2# heat exchanger (3) and the 3# pump (10) in turn and then returns to the solar collector field (8) to complete the cycle; in the Rankine cycle, the working fluid passes through After being pressurized, the 2# pump (5) enters the 3# heat exchanger (6) to absorb heat and evaporate, then enters the 2# turbine (7) to do work, then enters the 1# heat exchanger (2) for condensation, and finally enters 2# The cycle is completed in pump (5). 2. A Rankine cycle system for the combined use of solar energy and LNG cold energy according to claim 1, characterized in that LNG is pressurized through the 1# pump (1) and then enters the 1# heat exchanger (2) to be cooled. The amount is transferred to the Rankine cycle working fluid, and then enters the 2# heat exchanger (3) to be vaporized and heated, and then enters the 1# turbine (4) to do work. 3. A Rankine cycle system for joint use of solar energy and LNG cold energy according to claim 1, characterized in that the solar collector field (8) is connected to the storage tank (9) and can be used to deal with various emergencies. . 4. A Rankine cycle system for the combined use of solar energy and LNG cold energy according to claim 1, characterized in that the thermal working fluid at the outlet of the storage tank (9) is divided into two streams, and one stream enters the 3# heat exchanger ( 6) Medium-heat the Rankine cycle working fluid, and once it enters the 2# heat exchanger (3), the LNG is vaporized and heated. 5. A Rankine cycle system for joint use of solar energy and LNG cold energy according to claim 1, characterized in that the thermal working medium in the solar heat collection system is used as the heat source and LNG is used as the cold source.