JPS597002B2 - Power recovery device for low-temperature liquefied gas vaporization equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a system for effectively recovering the cold energy and pressure energy possessed by the low-temperature liquefied gas as motive energy in equipment that vaporizes and superheats low-temperature liquefied gas such as liquefied natural gas (LNG). The present invention relates to a power recovery device for low-temperature liquefied gas vaporization equipment.

Conventionally, low-temperature liquefied gas such as LNG is pressurized to 2 to 3 times or more than the gas working pressure using a pump, then vaporized and heated in a vaporizer using a heating source, and the gas is then pumped to the point of use. .

However, in this case, the cold energy possessed by the low-temperature liquefied gas is discarded into the heating source, and the pressure energy possessed by the vaporized gas pressurized by the pump is converted into velocity energy of the gas, so both the cold energy and the pressure energy are It is released into the outside world without being used effectively.

An object of the present invention is to provide a low-temperature liquefied gas, particularly LNG vaporization equipment, which is capable of effectively recovering the cold heat and pressure energy possessed by the low-temperature liquefied gas, which was conventionally released to the outside world. Our purpose is to provide a power recovery device. The power recovery device in the low-temperature liquefied gas vaporization equipment of the present invention that achieves this objective uses an intermediate heat medium as the heat source. In equipment that vaporizes low-temperature liquefied gas using intermediate heat medium vapor obtained by heating the gas, (a) a storage tank 1 for the low-temperature liquefied gas, a pump 2 that boosts the pressure of the liquefied gas, and a pump 2 that boosts the pressure of the liquefied gas, an intermediate heat medium type vaporizer 3 that vaporizes the gas by using an intermediate heat medium; an intermediate heat medium superheater 4 that superheats the vaporized gas with an intermediate heat medium; an expander 16 that expands the superheated gas and recovers power; A low wet liquefied gas vaporization/superheating system A4 consisting of an intermediate heat medium type reheater 1γ that superheats the gas passed through by an intermediate heat medium, and a superheater 5 that further heats the superheated gas using a heat source, connected in this order. (portion) An intermediate heat medium evaporator 6 that evaporates the intermediate heat medium using a heat source, an expander 8 that expands a part of the intermediate heat medium vapor to recover power, and the expanded intermediate heat medium vapor causes the low temperature to rise. The intermediate heat medium type vaporizer 3 that vaporizes the liquefied gas and condenses the intermediate heat medium vapor, the intermediate heat medium pump 9 that boosts the pressure of the condensed intermediate heat medium liquid, and the intermediate heat medium evaporator 6. A circulation system for a part of the intermediate heat medium connected in sequence, and another part of the intermediate heat medium vapor of the intermediate heat medium evaporator 6 are connected to the intermediate heat medium type superheater 4 and the intermediate heat medium type reheater. An intermediate heat medium supply/recovery system 10 configured integrally with the intermediate heat medium evaporator 6, which supplies and recovers the intermediate heat medium to the intermediate heat medium evaporator 6, respectively.
(c) a heat source is the intermediate heat medium evaporator 6 and the superheater 5;
and a heat source system C for supplying heat to the heat source system C, and is characterized in that the expander 16 of the vaporization/superheating system A4 and the expander 8 of the intermediate heat medium circulation system B4 are connected to a common driven machine 7. be.

Embodiments of the present invention will be described below based on the drawings.

In the figure, the low-temperature liquefied gas vaporization and superheating system (arrow A4) includes a storage tank 1, liquefied gas pump 2, intermediate heat medium type vaporizer 3, intermediate heat medium type superheater 4, expander 16, and intermediate heat medium type reheating system. It is constructed by connecting the heater 17 and the superheater 5 with this JM.

Circulation system for intermediate heat medium such as ethane and propane (arrow B4)
is branched into two systems from the intermediate heat medium evaporator 6, one of which is connected to the
The expander 8 connected to the driving machine 7 (this expander 8 and the expander 16 are connected to a common driven machine 7), the intermediate heat medium type vaporizer 3, and the intermediate heat medium pump 9 in this order. The intermediate heat medium is circulated through the intermediate heat medium evaporator 6 to the original intermediate heat medium evaporator 6, and the other is connected to the intermediate heat medium type superheater 4 by intermediate heat medium supply/recovery systems 10 and 18 that are integrally configured with the intermediate heat medium evaporator 6. and an intermediate heat medium type reheater 17, respectively.

Further, a heat source system (arrow Cl) for seawater or the like is configured by connecting the intermediate heat medium evaporator 6 and the superheater 5 in parallel after the heat source pump 11.

Next, the operation of the present invention will be explained.

Low-temperature liquefied gas such as LNG from tank 1 is pressurized by pump 2 to a pressure equal to the gas working pressure plus the total pressure loss of vaporization/superheating system A4, and in intermediate heat medium type vaporizer 3, ethane, propane, etc. The liquefied gas is vaporized by exchanging heat with the low-temperature, low-pressure steam of the intermediate heating medium, and taking away the heat from the intermediate heating medium.
On the other hand, the intermediate heating medium condenses.

The vaporized gas is passed through the intermediate heat medium type superheater 4 to a temperature higher than that in the intermediate heat medium type vaporizer 3 of the intermediate heat medium supplied from the intermediate heat medium evaporator 6 via the intermediate heat medium supply/recovery system 10. The intermediate heating medium is superheated by high-pressure steam and condensed.

The superheated gas is sent to the expander 16 and expanded,
At this time, the pressure energy possessed by the vaporized liquefied gas is effectively converted into mechanical energy and recovered.

The low-temperature liquefied gas vapor that has expanded in the expander 16 and becomes low temperature and low pressure again is sent to the intermediate heat medium type reheater 17.
After being superheated by heat exchange with the high pressure steam of the intermediate heat medium supplied from the intermediate heat medium evaporator 6 through the intermediate heat medium supply/recovery system 18, the intermediate heat medium is sent to the superheater 5, where seawater is It is further heated to near room temperature using heat sources such as heat sources, and then sent to the customer.

The intermediate heat medium is vaporized by a heat source in the intermediate heat medium evaporator 6 to generate high-pressure steam.

At this time, the pressure of the intermediate heat medium vapor inside the evaporator 6 is maintained such that the saturated vapor temperature of the intermediate heat medium is equal to or higher than the freezing point of the heat source.

The high-pressure steam of the intermediate heat medium generated in the evaporator 6 is divided into two systems, one of which expands in the expander 8 and becomes low-temperature, low-pressure steam.
The driven machine 7 recovers this energy as mechanical energy.

The low-temperature, low-pressure intermediate heat medium vapor vaporizes the low-temperature liquefied gas by imparting latent heat to the low-temperature liquefied gas in the intermediate heat medium type vaporizer 3 as described above, and at the same time, the intermediate heat medium vapor itself condenses.

The condensed intermediate heat medium liquid is pressurized by the intermediate heat medium pump 9 to the pressure inside the next intermediate heat medium evaporator 6 or higher,
The liquid is returned to the liquid reservoir in the evaporator 6, evaporated again by the heat source, and thereafter circulated.

In this way, the Rankine cycle using the intermediate heating medium as the working medium is completed, and the cold energy possessed by the low-temperature liquefied gas can be effectively recovered in the form of mechanical energy by the expander 8.

At the same time, another part of the high-pressure intermediate heat medium generated in the intermediate heat medium evaporator 6 is sent to the intermediate heat medium type superheater 4 via the intermediate heat medium supply/recovery system 10. Heat medium type vaporizer 3
The liquefied gas, which is still at a fairly low temperature after being vaporized at , is superheated, and the vapor itself is condensed and returned to the liquid reservoir in the intermediate heating medium evaporator 6 through the intermediate heating medium supply/recovery system 10, and at the same time. , are also sent to the intermediate heat medium type reheater 17 via the intermediate heat medium supply/recovery system 18, and the expander 1
The low-temperature liquefied gas that expanded in step 6 and became low temperature and low pressure again is superheated, and the vapor itself is condensed, and the intermediate heating medium supply/recovery system 1
8 and is returned to the liquid reservoir in the intermediate heat medium evaporator 6.

In this way, the intermediate heat medium evaporator 6 and the intermediate heat medium type superheater 4
, intermediate heat medium type reheater 11 and intermediate heat medium supply/recovery system 1
0 and 1B are integrally configured, the intermediate heat medium can efficiently connect the intermediate heat medium evaporator 6 to the intermediate heat medium type superheater 4 and the intermediate heat medium evaporator 6 to the intermediate heat medium type reheater 11. This improves the circulation efficiency of the intermediate heating medium, and since the intermediate heating medium is actively circulated, there is no risk of the heat source freezing, increasing the safety of the heat source against freezing.

Therefore, when the low-temperature liquefied gas is superheated by the intermediate heat medium vapor in the intermediate heat medium type superheater 4 and the intermediate heat medium type reheater 17, the heat source such as seawater is not solidified or blocked.

After the heat source such as seawater is pressurized by the heat source pump 11, the intermediate heat medium is heated in the intermediate heat medium evaporator 6 to generate high-pressure steam as described above, and then sent to the superheater 5 as described above. The vaporized and superheated liquefied gas is further heated to around room temperature and then supplied to subsequent customers.

Seawater, which has a relatively high freezing point, can be used as a heat source.
In this heat source system, the low-temperature liquefied gas can be efficiently vaporized and heated to around room temperature without clogging due to solidification of the heat source.

In this way, according to the above embodiment, the cold energy released when the low-temperature liquefied gas is vaporized is recovered by the expander 8, and the pressure of the low-temperature liquefied gas in the low-temperature liquid state is increased by the pump 2 with less energy. The pressure energy stored when the expander 16
This makes it possible to effectively recover power energy.

Since the power recovery device for the low-temperature liquefied gas vaporization equipment of the present invention is configured as described above, it can effectively recover the cold energy possessed by the low-temperature liquefied gas as power energy, and further convert the low-temperature liquefied gas into low-temperature It is also possible to effectively recover the pressure energy held when the pressure is increased in the liquid state as motive energy.

Therefore, it is possible to increase the amount of recovered energy and improve the efficiency of energy recovery and utilization.

Further, an intermediate heat medium evaporator 6, an intermediate heat medium type superheater 4, an intermediate heat medium type reheater 17, and intermediate heat medium supply/recovery systems 10, 1
8 is integrally configured, it is possible to improve the circulation efficiency of the intermediate heat medium and to improve the safety against freezing of the heat source.

Furthermore, seawater or the like can be used as the heat source, which is advantageous in terms of cost, and there is no risk of the heat source system solidifying or clogging.

As described above, according to the present invention, it is possible to effectively recover the cold heat and pressure energy possessed by low-temperature liquefied gas, which was conventionally released to the outside world, as motive energy, and the practical effects thereof are extremely remarkable. .

[Brief explanation of the drawing]

The figure is an overall system diagram showing an embodiment of the present invention. A4... Low temperature liquefied gas vaporization/superheating system, B4.
-...Intermediate heat medium circulation system, C1...Heat source system,
1...Storage tank, 2...Low temperature liquefied gas pump, 3...Intermediate heat medium type vaporizer, 4...
...Intermediate heat medium type superheater, 5...Superheater, 6.
...Intermediate heat medium evaporator, γ...Driven machine,
8... Expander, 9... Intermediate heat medium pump, 10, 18... Intermediate heat medium supply/recovery system, 11... Heat source pump, 16...--Expander, 11...Intermediate heat medium type reheater.

Claims (1)

[Scope of Claims] 1. A facility for vaporizing low-temperature liquefied gas using intermediate heat medium vapor obtained by heating an intermediate heat medium with a heat source, including: (a) a storage tank 1 for low-temperature liquefied gas, which pressurizes the liquefied gas; A pump 2, an intermediate heating medium type vaporizer 3 that vaporizes the pressurized liquefied gas using an intermediate heating medium, an intermediate heating medium type superheater 4 that superheats the vaporized gas using an intermediate heating medium, and an intermediate heating medium type superheater 4 that expands the overburned gas. An expander 16 that recovers power through the expander 16, an intermediate heat medium type reheater 11 that superheats the gas that has passed through the expander 16 using an intermediate heat medium, and a superheater 5 that further heats the superheated gas using a heat source are connected in this order. ←) An intermediate heat medium evaporator 6 that evaporates the intermediate heat medium using a heat source, and an expander 8 that expands a part of the intermediate heat medium vapor to recover power. , the intermediate heat medium type vaporizer 3 that vaporizes the low-temperature liquefied gas by the expanded intermediate heat medium vapor and condenses the intermediate heat medium vapor; and the intermediate heat medium pump that increases the pressure of the condensed intermediate heat medium liquid. 9. A circulation system for a part of the intermediate heat medium formed by connecting the intermediate heat medium evaporators 6 in this order, and another part of the intermediate heat medium vapor of the intermediate heat medium evaporator 6? an intermediate heat medium supply/recovery system 10.1 configured integrally with the intermediate heat medium evaporator 6, which supplies and recovers the intermediate heat medium type superheater 4 and the intermediate heat medium type reheater 17, respectively;
an intermediate heat medium circulation system B4 consisting of 8;
A low-temperature liquefaction system comprising a heat source system C for supplying heat to the evaporation and superheating system A4, and an expander 16 of the vaporization/superheating system A4 and an expander 8 of the intermediate heat medium circulation system B4 connected to a common driven machine 7. Power recovery device for gas vaporization equipment.