JPH0551587A - Parallel production of natural gas substitute and electricity - Google Patents

Abstract

PURPOSE:To economically produce a natural gas substitute and generate electricity in parallel in the process wherein coal is hydrogenated and gasified at a high temp. and a high pressure to produce the substitute, which is cooled to produce a liquefied natural gas substitute, and electricity is generated by burning the substitute. CONSTITUTION:Electricity is generated mainly by burning the natural gas substitute when the demand for electricity is high, and the substitute is liquefied by cooling mainly by using a part of the generated electricity when the demand for electricity is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention produces alternative natural gas (hereinafter referred to as SNG) by hydrogasification of coal.
On the other hand, SN that uses the produced SNG to generate thermal power
The present invention relates to a parallel production method of G and electric power.

[0002]

2. Description of the Related Art Coal is an energy source that is widely distributed worldwide, has abundant reserves, and is stable in price. After the oil crisis, it was reviewed, and the gasification method of coal was studied as a more efficient use method, and it has already been put to practical use. Various methods are known for the gasification of coal. For example, the main component of the hydrogen gas obtained by reacting coal with high-temperature, high-pressure steam is carbon monoxide and hydrogen, and it is called a low-calorie gas. .. Also, by mixing pulverized coal with light oil,
There is a method of producing methane by acting high pressure hydrogen and steam, and a method of acting oxygen and steam at high temperature and pressure.

[0003]

Attempts have been made to integrate a coal gasifier and a power generator and use the gas obtained by gasification as a fuel for thermal power generation. When producing power generation fuel by gasification of coal, the gasifier produces stable-quality gas at low cost, and therefore it is preferable to increase the operating rate as much as possible and keep the production amount stable for stable operation. On the other hand, in the electric power industry, fluctuations in electric power demand, particularly an increase in the day-night demand gap, has become a big problem. Especially 1 am
From midnight to 5 pm, the demand for daytime is high, while the demand for nighttime is low. For this reason, medium-scale thermal power generation facilities have been adopted so that they are stopped for a short period at night and started in the early morning.

As described above, it is desired that the amount of power generation be elastically changed in accordance with the change in electric power demand. When integrating a coal gasifier and a power generator, how to satisfy the requirements of each device has become a major issue.

[0005]

[Means for Solving the Problems] As a result of intensive studies on the above problems in using the fuel obtained by gasification of coal for power generation, the present inventors have adopted a specific coal gasification process. It was found that the above problems can be solved by combining the above and the power generation device in a specific method,
The present invention has been completed.

That is, according to the present invention, SNG containing methane as a main component is produced by hydrogenating coal under high temperature and high pressure.
In order to produce a liquefied SNG by cooling the SNG and burning the SNG to generate electricity,
During the time when the power demand is large, the SNG is mainly burned to generate power, and during the time when the power demand is small, the SNG is mainly cooled by using a part of the generated power to produce the liquefied SNG. Is a parallel production method of SNG and electric power.

[0007]

The gasification of coal adopted in the present invention is a process in which high temperature and high pressure hydrogen is applied to coal to finally obtain an alternative natural gas (SMG) containing methane as a main component.

[0008] By the way, natural gas has a richer reserve than petroleum, and NOx and S, which are pollution sources when burned.
The amount of Ox generated is small, and the demand is increasing as a clean energy source. In particular, the conversion of city gas from LPG to liquefied natural gas (LNG) has recently been promoted.
In the electric power industry as well, in view of the trend of tightening carbon dioxide emission regulations in addition to NOx and SOx, there is a tendency to switch to LNG, which produces a relatively smaller amount of carbon dioxide than coal and heavy oil. In order to secure this LNG supply system, SNG has literally received attention as an alternative fuel, and is becoming more important as the above-mentioned city gas or fuel for power generation.

In the present invention, as a coal gasification process,
Adopting a hydrogenation method that can obtain SNG that can be liquefied and stored in a container, combine this with a power generator, and operate the refrigerator using surplus power at night when power demand is small,
SNG produced by gasification is stored as liquefied SNG. During the daytime when the power demand is large, the stored liquefied SNG is vaporized and used as a fuel for power generation, and the cold heat obtained when the liquefied SNG is vaporized is effectively used. That is, the cold heat required for the liquefaction of the produced SNG, the cold heat required for the separation of unreacted hydrogen and the produced gas (hydrogen refining), and the oxygen required for the gasification process of coal from the air are produced by the cryogenic separation device. It is used as the cold heat required when doing. In this way, it is possible to ensure stable production of gasifiers and cope with fluctuations in power demand while optimizing the overall energy balance. Of course, the surplus SNG is also used for city gas.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIG. FIG. 1 schematically shows the flow of devices, products, etc. used in the SNG and electric power parallel production method of the present invention. Note that FIG. 1 shows only the main devices and main products, and omits many of the auxiliary devices such as heat exchangers, pumps, refining devices, and tanks. In addition, only major products are shown.

In the hydrogasification furnace 1 of FIG. 1, coal and hydrogen are brought into contact with each other under high temperature and high pressure to obtain char of produced gas containing methane as a main component and residual char. The produced gas is cooled by the heat exchanger 4 to separate benzene and ammonia, and then the produced gas purification device 5 removes the acidic gas, converts carbon monoxide into methane by methanation, and the like, for purification. After that, unreacted hydrogen and methane as a main component are separated by the cryogenic separator 6 to obtain SNG.

The separated hydrogen uses cold heat in the heat exchanger 4 and is returned to the hydrogasification furnace 1 together with hydrogen from a shift converter 10 described later. The obtained SNG is used in a power generator 9 such as a gas turbine combined cycle power generator or a steam turbine to generate steam and a steam turbine power generator.

The obtained electric power is mainly used for the electric power of the refrigerator 7 in the system, and the surplus electric power is supplied to the outside of the system. If necessary, the SNG is further heat-treated through a dryer or the like, or subjected to increased heat treatment with propane or the like, liquefied by the refrigerator 7, and liquefied SNG.
It is stored as and becomes a supply source of city gas. Liquefied SNG
In the system, is vaporized through the vaporizer 8 and consumed as SNG in the power generator 9. In the vaporizer 8, cold heat is obtained by the latent heat of vaporization of the liquefied SNG, so cold heat to the deep-chill separator 6, cold heat to the cooler of the SNG attached to the refrigerator 7, and cold heat to the air separator 3 described later. It can be used as a source.

On the other hand, char as a by-product generated from the hydrogasification furnace 1 is reacted with high temperature steam and oxygen by the partial oxidation furnace 2 to be converted into a gas containing carbon monoxide and hydrogen as main components, and further, The shift converter 10 removes carbon monoxide by steam and refines the hydrogen to supply hydrogen to the hydrogenation gasification furnace 1.

Oxygen used in the partial oxidation furnace 2 is produced by separating air in the air separation device 3 by the deep-chill separation method.
At that time, the cold heat obtained from the vaporizer 8 is used. The surplus char may generate steam as fuel to be used for power generation.

In the present invention, the hydrogasification furnace is operated stably at a constant production speed in order to stabilize the quality of the produced gas and to produce it at low cost. On the other hand, since the power demand fluctuates like a day-night gap, for example, during the daytime when demand is high, the stored liquefied SNG is vaporized and used in the power generator 9.
The utilization of the cold heat generated by the vaporization of the liquefied SNG is as described above. On the other hand, at night when the power demand is small, for example, the surplus SNG used for power generation and excluding SNG from the produced SNG operates the refrigerator using the surplus power from the power generator, and is stored in the tank as liquefied SNG. It serves as a source for daytime power generation or city gas.

[0017]

As described in detail above, by adopting the method provided by the present invention, the coal gasifier and the power generator in the hydrogenation method are integrated, and the stable operation and power of the gasifier are achieved. It has also become possible to deal with fluctuations in the amount of power generation that accompanies fluctuations in demand.

[Brief description of drawings]

FIG. 1 is a systematic diagram of devices, products, and the like used in the parallel production method of SNG and electric power by gasification of coal of the present invention.

Claims (1)

[Claims] 1. An alternative natural gas is produced by hydrogenating coal under high temperature and high pressure, the alternative natural gas is cooled to produce a liquefied alternative natural gas, and the alternative natural gas is burned to generate electricity. In the alternative natural gas parallel production power generation method, the alternative natural gas is mainly burned to generate power during a time when the power demand is large, and a part of the generated power is mainly used during a time when the power demand is small. A method for parallel production of alternative natural gas and electric power, comprising cooling the alternative natural gas to produce liquefied alternative natural gas.