JPH03294627A - Coal gasification power generating method - Google Patents

Abstract

PURPOSE:To easily adjust a supply quantity of coal by blowing coal methanol slurry mixed of methanol synthesized from one pat of coal gasified gas and fine coal in a coal gasification furnace. CONSTITUTION:Coal is supplied to a mill 15, methanol is also supplied from a methanol line 16 to the mill, and coal methanol slurry is produced by crushing coal into fine coal and mixing with methanol. The coal methanol slurry produced in the mill 15 is blown into a coal gasification furnace 1 through a fuel line 3, and gasifying agent such as air or oxygen is also blown in it from a gasifying agent line 2, hence coal is partially burnt (oxidation) under the condition of high temperature (about 1200 - 1600 deg.C) and high pressure (about 20 - 40 kg/cm<2>), and deoxidated to generate coal gasifying gas as synthesis gas containing water gas. Because coal is blown in the furnace 1 as coal methanol slurry, coal supply quantity can be easily adjusted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coal gasification power generation method for generating electricity by supplying coal gasification gas produced in a coal gasifier under high temperature and high pressure to a gas turbine. In particular, it relates to a coal gasification power generation method in which coal methanol slurry is injected into a coal gasifier.

[Conventional technology] In recent years, in order to gasify coal, coal and air are blown into a coal gasifier under high temperature and high pressure, where the coal is partially combusted (M) and reduced to produce coal gasification. Attempts have been made to generate gas and supply it to a gas turbine to generate electricity.

[Problems to be Solved by the Invention] By the way, there are two methods for feeding coal into a coal gasification furnace: a dry method in which dry pulverized coal is conveyed with nitrogen gas or the like and blown into the furnace;
There is also a wet method in which pulverized coal is made into a water slurry and blown into the furnace. In the case of a dry type, it is difficult to control the amount of coal supplied into the furnace, making it difficult to respond to load changes.

On the other hand, in the case of wet type, it is easy to control the flow rate of coal, but
Since the calorific value of the large amount of water in the coal-water slurry is small, the water absorbs latent heat of vaporization and evaporates, resulting in a problem of increased heat loss and decreased thermal efficiency.

Therefore, the present invention was made to solve the above problems, and an object of the present invention is to provide a coal gasification power generation method that can adjust the amount of coal supplied and improve thermal efficiency.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and includes partially oxidizing and reducing coal in a high-temperature, high-pressure coal gasifier to generate coal gasified gas, In a coal gasification power generation method in which the generated coal gasified gas is supplied to a gas turbine to generate electricity, methanol is synthesized from a part of the generated coal gasified gas, and the methanol is mixed with powdered coal. Coal methanol slurry is injected into the gasifier.

1 Effect] According to the above configuration, since the coal is blown into the furnace as powdered coal or coal-methanol slurry, the amount of coal supplied can be easily adjusted. Since the calorific value of the slurry is also increased, heat loss is relatively low and thermal efficiency is improved.

Furthermore, since the methanol used in the methanol slurry is synthesized from a portion of the coal gasification gas produced in the coal gasifier, the overall efficiency is improved.

[Embodiment 1] Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

In Figure 1, 1 indicates coal at a high temperature (approximately 1200 to 160
It is a coal gasification furnace that gasifies under high pressure (approximately 20-40 kg/cry).

A gasifying agent such as air or oxygen is added to the coal gasifier 1.
A gasifying agent line 2 for injecting into the tank is connected, and a fuel line 3 is also connected.

Further, a gas line 4 for discharging the generated coal gasification gas is connected to the coal gasification furnace 1, and the gas line 4 is provided with a gas cooler 5 and a gas purification device 6. The gas line 4 is connected to a gas turbine 7, and the turbine 7 drives a generator 7a.

An exhaust line 8 is connected to the turbine 7, and an exhaust heat recovery boiler 9 is interposed in the exhaust line 8. A steam line ↓O is connected to the exhaust heat recovery boiler 9 and the gas cooler 5, and this line 10 is connected to the steam turbine 11.
The steam turbine 11 generates a generator 11a.
is driven.

Further, in the gas line 4 leading from the gas purification device 6 to the gas turbine 7, a slanted flow rate control valve 13 is provided to supply surplus coal gasification gas in the line 4 to the methanol synthesis device 12.
A synthesis line 14 is connected thereto. The methanol synthesis device 12 is configured to synthesize methanol by passing water gas in coal gasification gas over a catalyst mainly composed of zinc oxide (e.g., zinc chromite) under high temperature and high pressure, A storage tank 12a is provided to store synthesized methanol. Incidentally, the methanol synthesis apparatus may be any apparatus as long as it synthesizes methanol from coal gasification gas.

A methanol line 16 is connected to the methanol synthesis device 12 for supplying methanol to a mill 15 serving as a slurry production device. The mill 15 is supplied with coal and methanol from a methanol line 16, so that while the coal is crushed into powder, the crushed coal and methanol are mixed to produce a coal-methanol slurry. This mill 1
5 is connected to the fuel line 3, and the coal methanol slurry produced in the mill 15 is blown into the coal gasifier 1 through the fuel line 3.

Next, the operation of this embodiment will be explained.

The coal methanol slurry produced in the mill 15 is blown into the coal gasifier 1 via the fuel line 3, and
A gasifying agent such as air or oxygen is blown through the gasifying agent line 2, where the coal is heated to a high temperature (approximately 1200-1600'
C) Partially combusted (oxidized) and reduced under high pressure (approximately 20-40 kg/csK) to produce syngas coal gasification gas containing hydro-I'lE gas.

In this way, since the coal is blown into the furnace 1 as a coal-methanol slurry, the coal flow rate can be easily adjusted. In addition, because the calorific value of the methanol in the coal-methanol slurry is large, the heat loss when the methanol evaporates by taking away the latent heat of vaporization within Class 1 is relatively small, improving thermal efficiency and gasification efficiency. I will do it.

For this reason, in coal gasifier equipment that injects coal-methanol slurry, the fuel supply equipment can be made smaller by the amount of heat generated compared to the same scale as in the case of conventional dry type or coal-water slurry. become.

Coal gasification gas produced in the coal gasification furnace 1 is discharged into a gas line 4, cooled by a gas cooler 5, and recovered as sensible heat of the gas or steam. The cooled gasification gas is dedusted and desulfurized in the gas purification device 6, and then supplied to the gas turbine 7, where it is combusted to rotate the turbine 7 and drive the generator 7a to generate electrical energy.

The exhaust gas from the gas turbine 7 passes through an exhaust line 8 to an exhaust heat recovery boiler 9 where sensible heat is recovered and steam is generated.

This steam is supplied to a steam turbine 11 through a steam line 10 together with the steam generated by the gas cooler 5, where the turbine 11 is rotated and electrical energy is generated by a generator 11a.

During this operation, when the power load decreases (the amount of power generation is low), the opening degree of the flow rate control valve 13 of the synthetic line 14 is opened according to the power load, especially during times when power demand is low (for example, at night). , excess coal gasification gas that has passed through the gas purification device 6 is introduced into the methanol synthesis device 12.

The gasification gas introduced into the methanol synthesis apparatus 12 has water gas (Co, H,) in the gas at a high temperature (approximately 300 to 40
methanol (CH
30H) is synthesized.

CO-1-2H2→CH,OH An appropriate amount of the synthesized methanol is supplied to the mill 15, where it contributes to the production of coal methanol slurry, and the remainder is stored in the storage tank 12a. In this way, methanol is synthesized using surplus coal gasification gas during times when electricity demand is low, and a portion of the methanol is stored in tanks 1 and 2a, which can then be used during normal electricity loads such as during the daytime. This can contribute to the production of coal-methanol slurry, thus improving the overall efficiency of the power generation method.

In other words, in order to partially oxidize and reduce the coal by maintaining the inside of the coal gasification furnace 1 at high temperature and pressure by burning a portion of the coal, the operating conditions of the furnace 1 become difficult when the load fluctuates, so the electric power is It is difficult to vary the load on the gasifier 1 according to the load. Therefore, by synthesizing methanol with surplus coal gasification gas when the power load is reduced, gasification operation can be performed at a constant load without reducing the load on the coal gasifier 1 even when the amount of power generation is low. Become. As a result, gasification operation can be performed at a constant load, and the thermal efficiency of the coal gasification furnace 1 can be improved using surplus coal gasification gas when the power load is reduced, making effective use of surplus coal gasification gas. This will improve the overall efficiency of the entire power generation method.

In addition, in this example, the case where methanol is synthesized using excess coal gasification gas when the power load is reduced has been explained, but even during normal load, gasification operation is performed to synthesize methanol using a part of the coal gasification gas. You can do it like this.

[Effects of the Invention] In summary, according to the present invention, by injecting coal methanol slurry, which is a mixture of methanol synthesized from a part of coal gasification gas and powdered coal, into a coal gasification furnace, the amount of coal supplied can be increased. can be easily adjusted and improve thermal efficiency.
It also has the excellent effect of improving overall efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a coal gasifier, 7 is a gas turbine, 12 is a methanol synthesis device, and 15 is a slurry production device. 7...7;j 2nd order 6°° Zuigo 9P 7...Power" Star Shin 72... Tutanol rate eight negative i 75...Zurasoyu draft is also 4gL

Claims (1)

[Claims] 1. In a coal gasification power generation method in which coal is partially oxidized and reduced in a high-temperature, high-pressure coal gasifier to generate coal gasification gas, and the generated coal gasification gas is supplied to a gas turbine to generate electricity. , a coal gasification power generation method characterized in that methanol is synthesized from a part of the coal gasification gas produced above, and a coal methanol slurry obtained by mixing the methanol and powdered coal is blown into the coal gasification furnace. .