JPS6038598B2 - Natural gas supply equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an apparatus for directly supplying natural gas to consumers, in which excess natural gas is liquefied and stored during off-peak hours, and the stored liquefied natural gas (LNG) is This relates to a device that revaporizes and supplies to the consumer side during peak hours.

Conventional countermeasures for off-peak and peak times include the first
It was equipped with the equipment shown in the diagram.

This equipment consists of a main line B that supplies natural gas directly from the natural gas supply side A to the consumer side, a liquefaction device C that liquefies surplus natural gas, and an LNG storage tank D that stores the liquefied natural gas. and a vaporizer E for revaporizing and supplying this liquefied natural gas at peak times.The liquefier C has an expansion type, a cascade type, an MCR (
Mixed cold soot system) was used, and all of these systems used external power for driving. Therefore, there is a drawback that a large amount of electricity is consumed to liquefy surplus natural gas, leading to an increase in liquefaction cost. For example, LNG8
, 330 kg (at 11,667 N), 361 KW is required as power for driving the compressor and the like. Further, when revaporizing LNG, hot soot for revaporization and electric power for operation are required, and this also relies on external electric power. The present invention has been proposed in view of the above, and an object of the present invention is to propose a natural gas supply device that can liquefy and revaporize surplus natural gas without consuming external power. . The present invention provides, as means for achieving the above object, a main line that directly supplies natural gas to the consumer side, a peak shaving line that branches off from the main line and finally joins the main line again; a liquefaction device installed in the peak shaving line; and a liquefier installed in the peak shaving line;
an NG storage tank, a revaporization device that pumps out LNG stored in the LNG storage tank and revaporizes it in the peak shaving line, and a part of the natural gas passing through the main line as fuel for the high temperature section side. The present invention proposes a natural gas supply device comprising a Stirling engine configured to use the generated driving force as a driving source for the liquefaction equipment, and a generator driven by the driving force of the Stirling engine. be.

According to the present invention, when surplus natural gas is generated during off-peak hours, the cooling engine drives the liquefaction device to liquefy the surplus natural gas and temporarily stores it in the LNG storage tank. The LNG can be pumped out and re-vaporized using a vaporizer and then supplied.

In this way, by using the Stirling engine to drive the liquefaction equipment, or by driving the Stirling engine to operate a generator and using this electromotive force for the liquefaction equipment or other power sources within the equipment, external power can be generated. It becomes possible to operate the device without using any electricity, and it is possible to reduce the cost of supplying natural gas.

Examples of the present invention will be described in detail below.

1 is a natural gas supply line, and the natural gas supplied through this line is normally directly supplied to the consumer side 3 through a main line 2.

4 is a Stirling refrigerator, and this Stirling refrigerator 4 is directly driven by a Stirling engine 6.

5 is a branch line for guiding excess natural gas from the main line 2 to the Stirling refrigerator 4; 8 is an LNG storage tank for storing liquefied natural gas, that is, LNG, liquefied by the Stirling refrigerator 4; 9 is an LNG storage tank; A pump for sending LNG in the storage tank 8 to the vaporizer (revaporizer) 10
G is a structure in which the vaporizer 101 re-vaporizes the trowel and supplies it to the consumer side 3.

In addition, in the above configuration, the branch line 5, the Stirling refrigerator 4, the LNG storage tank 8, and the vaporizer 10
A series of lines including the peak shaving line is called a peak shaving line. 7 is a fuel gas line that recovers a part of the natural gas from the main line 2 that supplies natural gas to heat the high-temperature section 6' of the Stirling engine 6, and combusts this gas to generate the Stirling engine. The Stirling engine 6 is driven by heating the high temperature section 6' of No. 6 to a high temperature (70,000 ℃).

Reference numeral 11 denotes a generator driven by the Stirling engine 6, and the electric power generated by this generator serves as a power source for the drive motor of the pump 9, or is used as a necessary power source within the apparatus.

12 is for guiding the LNG discharged from the LNG storage tank 8 to the low-temperature section 6'' of the Stirling engine 6, and sending the vaporized natural gas to the consumer side 3 by heat exchange in the low-temperature section 6''. This is the revaporization line.

The Stirling engine 6, the line 7 that supplies natural gas for fuel to the Stirling engine 6, and the Stirling refrigerator are collectively referred to as a Stirling drive line. The embodiment has the above-mentioned configuration, and its operation will be explained next.

Natural gas supplied to general consumers during off-peak hours is directly supplied via the main line 2.

When surplus natural gas is generated, this surplus natural gas is sent to the Stirling refrigerator 4. The Stirling refrigerator 4 is directly driven by a Stirling engine 6 which is operated by burning natural gas partially recovered from the main line 2 in a high temperature section 6' to liquefy excess natural gas. This liquefied natural gas, ie, LNG, is temporarily stored in the LNG storage tank 8. During peak hours, the Stirling engine 6 is operated in the same way as during off-peak hours to drive the generator 11, and the electromotive force generated by this drive rotates the pump 9 to
LNG is pumped out from the NG storage tank 8 and guided to the vaporizer 10', where it is re-vaporized using the vaporizer 01 and supplied to the consumer side 3.

Alternatively, part or all of the LNG is guided to the low-temperature section 6'' of the Stirling engine 6, and is re-vaporized by heat exchange in the low-temperature section 6 and sent to the consumer side 3. Instead of the refrigerator 4, a liquefaction device using an expansion method, a cascade method, an MCR method, etc. is used, and the power necessary for operating this device is provided by the generator 1.
Alternatively, the generator 11 may be rotated by an external power source using a generator that also serves as a motor, and the liquefaction device may be operated by this rotation when, for example, the Stirling engine malfunctions.

In addition, when operating the Stirling engine 6, it is possible to increase the output by using natural gas in the high temperature section 6' and by using the cold heat of LNG in the low temperature section 6'', or by using only one of them. As described above, the present invention utilizes a Stirling engine in a natural gas supply system to convert excess natural gas during off-peak hours into LNG and temporarily store it, and during peak hours, the LNG is stored. Since LNG is re-vaporized and supplied, there is no need for any external power, and compared to the conventional method of storing surplus natural gas and re-vaporizing it, operating costs are lower and equipment is simpler, resulting in economical effects. is enormous.

For example, by burning natural gas in the high temperature section of Stirling engine 6, 973K (70,000
When the low temperature section 6'' is kept at room temperature 300 K (27 DEG C.) by water cooling or air cooling, the theoretical efficiency of the engine is determined by the temperature difference between the high temperature section 6' and the low temperature section 6''.

In other words, efficiency = TH - T K low temperature part temperature) TH (high temperature part temperature) According to the above conditions, the value is 0.69.

The amount of natural gas consumed in the conventional LNG conversion shown in Figure 1 is 121, assuming the power generation efficiency of a thermal power plant as 0.39.
It becomes 2N〆. So, if we drive a Stirling engine with this 1212N natural gas, it will produce 9.21W.
power can be extracted. When a Stirling refrigerator is operated with this power, the theoretical efficiency of the refrigerator is TL = THG poison overflow temperature) - TL (low temperature temperature).
Assuming that it is operated at room temperature, the sword = 0.60.

That is, the 9th and 21st order Wxo. 60=5527KW is the net energy to convert natural gas to LNG. LNG
The energy to liquefy 1k9 is approximately 220kcal
/k9, so 5527×860/220=216
06 kg, and this amount of natural gas can be produced in 121 states. However, this is a theoretical value, and in reality, the actual efficiency of the Stirling engine and Stirling refrigerator is lower than the theoretical efficiency, so even if the actual efficiency of each is 70%, approximately 1 female 00k9 of LNG can be produced. , which exceeds the conventional liquefaction amount. Next, in the high temperature section 6' of the Stirling engine 6, natural gas is combusted to produce 97.
The LNG is heated to 700oC, and LNG for re-vaporization is sent to the low temperature section 6'' to vaporize the LNG in this low temperature section.
If this latent heat of vaporization and rattan heat is taken away from the working gas of the Stirling engine 6 and 1,270k9 of LNG is vaporized, the theoretical efficiency of the engine is 0.79, which theoretically produces a power of 1,21 kW. is obtained.

Note that if the actual efficiency is 70%, power of 85th order W can be obtained. This power is used within the base as a power source (260 KW) for the LNG pump 9, etc., and as a power source for air conditioning. In addition, in Fig. 2, 13 is used to collect the boil gas in the LNG tank 8 to the inlet side of the refrigerator and re-LNG it.
This is a boil gas recovery line that performs As described above, the present invention drives a Stirling engine with a portion of surplus natural gas during off-peak hours at a natural gas supply base, uses this driving force to liquefy and store the surplus natural gas, and during peak hours The stored liquefied natural gas is re-vaporized and sent to the consumer side, and the generator is driven by the Stirling engine to provide the necessary electricity within the base, so measures can be taken during peak and off-peak demand. There is an effect that can be achieved at low cost within the base.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional natural gas supply system, and FIG. 2 is a configuration diagram of the system of the present invention. 1. ．． ．． ．． ．．・Natural gas supply joint side, 2... Main line, 3... Consumer side, 4... Stirling refrigerator, 5... Diversion line, 6 ...・
... Stirling engine, 7 ... Fuel gas line, 8 ... LNG storage tank, 9 ... Pump, 10 ... Beacon/gas riser, 11 ... Generator ,
12...Revaporization line. Granny “Figure 2

Claims (1)

[Scope of Claims] 1. A main line that directly supplies natural gas to consumers, a peak shaving line that branches off from the main line and eventually joins the main line again, and a peak shaving line that branches off from the main line and eventually joins the main line again. a liquefaction device installed in the peak shaving line;
an LNG storage tank for storing LNG liquefied in the liquefaction device; a revaporization device for pumping out LNG stored in the LNG storage tank and revaporizing it in the peak shaving line; and in the main line. a Stirling engine configured to use a portion of the natural gas passing through as a fuel on the high-temperature side side and use the generated driving force as a driving source for the liquefaction device; and a generator driven by the driving force of the Stirling engine. A natural gas supply device consisting of . 2. The natural gas supply device according to claim 1, which is configured to generate electricity by driving a generator with a Stirling engine, and use this electricity to drive a liquefaction device.