JPH0559954B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a coal gasification combined cycle system that sends combustible gas produced in a coal gasifier to a gas turbine, and particularly relates to This invention relates to a coal gasification combined cycle power generation system that can ensure the safety of a gasifier and a pressure vessel with a suitable starting means.

(Prior Art) FIG. 2 shows an example of the configuration of a conventional coal gasification complex and its starting system.

This conventional gasifier 1 has 100
A fireproof insulation material of ~150 mm or more is provided, the upper part is a gasification part, the lower part is a cooling part, and a radiant cooler 2 is provided in the cooling part. The upper part of the gasifier 1 is provided with an inlet for coal 3, a gasifying agent 4 such as oxygen or air, and a starting fuel 5, and the lower part is provided with a produced gas outlet 6 and a slag outlet 7. .

The gas exiting the gas outlet 6 undergoes heat exchange in a heat exchanger 8, passes through a dust removal device 9 and an H ₂ S desulfurization device 10, and is sent to a gas turbine 11 to generate electricity. Reference numeral 12 denotes a flare stack that combusts gas during startup that is not fed to the gas turbine 11.

Gasifier 1 of the coal gasification complex device as described above
is lined with thick fireproof insulation material, so it takes a long time to warm up, and the starting fuel is 5.
It has the disadvantage of increasing the amount of

Furthermore, at startup, water vapor does not flow to the superheater in the heat exchanger 8, so the gas temperature at the inlet of the heat exchanger 8 must be kept low, but since cooling is insufficient with only the radiant cooler 2, the may even need to be injected for cooling. Such cooling by water injection is not only uneconomical, but also may cause problems due to drainage on the downstream side.

Furthermore, in the case of the one-stage spouted bed method as mentioned above,
The drawback is that it takes a long time to switch from starting fuel to coal and then to gasification.

(Problems to be Solved by the Invention) The present invention enables a short startup time, a reliable means of purging the gas generated from the startup fuel, and maintains the reliability of gas turbine combustion. The present invention aims to provide a coal gasification combined cycle power generation system that can simultaneously ensure the safety of pressure vessels.

(Means for Solving the Problems) That is, the present invention provides a coal gasification complex that sends combustible gas generated in a coal gasifier placed in a pressure vessel to a gas turbine via a dedusting means and a desulfurization means. In the power generation device, a starting fuel supply means is provided in the coal gasification furnace, and gas is branched and extracted from a pipe line between the dust removal means and the desulfurization means and guided to a bypass line leading to the flare stack and into the pressure vessel. a purge line, an exhaust line for guiding the gas in the pressure vessel to the flare stack, and a combustion line for branching and extracting gas from a pipe line between the desulfurization means and the gas turbine and guiding it to the flare stack; The combined coal gasification apparatus is characterized in that it is provided with a differential pressure control line leading into the pressure vessel via a compressor and an accumulator.

Hereinafter, one embodiment of the coal gasification combined cycle power generation apparatus of the present invention will be described in detail with reference to FIG.

Inside the pressure vessel 1, a comparator 3 is surrounded by a relatively thin (approximately 50 mm or less) water-cooled wall 2 and burns fuel to form a high-temperature atmosphere, and is located above the comparator 3 and communicates with the comparator 3. and a diff user 4 which carbonizes and thermally decomposes the fuel and mixes the high-temperature gas from the comparator 3 with the fuel; A gasifier 6 consisting of a reductor 5 gasifying the carbon grains from 4 is inserted. A heat exchanger group consisting of a flue evaporator 7, a superheater 8, and a economizer 9 is installed in the upper part of the gasifier 6 in order from the bottom, and an ash hopper 10 is installed in the lower part of the gasifier 6. ing.

The gas generated from the gasifier 6 exchanges heat with a group of heat exchangers and is supplied to a gas turbine 13 via a dust removal means 11 and a desulfurization (H ₂ S desulfurization) means 12, and the ash discharged from the comparator 3 is The ash is water-cooled through the ash hopper 10 and discharged outside the system as water-cooled slag.

As mentioned above, the gasifier 6 is composed of the combustor 3, the diff user 4, and the reductor 5,
A part of the fuel is fed into the comparator 3 and the rest is fed into the differential user 4 in a two-stage spouted bed system.

In the space 14 between the pressure vessel 1 and the gasifier 6,
Purified gas obtained by refining generated gas is injected through a differential pressure control line 15, a compressor 16, an accumulator 17, and a control valve 18, so that the pressure in the space therebetween can be controlled.

In addition, the comparator 3 of the gasifier 6 contains coal 19,
A gasifying agent 20 such as air or oxygen and a starting fuel 21 of oil or gas type are introduced. A portion of the coal 19 is also fed into the differential user 4.

Hereinafter, a method of starting up the device of the present invention will be explained.

When starting up the gasifier 6, the starting fuel 21 is put into the comparator 3, and combustion is performed in a relatively low O ₂ state, and this combustion gas is used to start the gasifier 6.
Warming is carried out. The exhaust gas used for warming passes through the dust removal means 11 from the upper part of the furnace 6, and then passes through the startup purge line 22, which branches from the pipe between the dust removal means 11 and the desulfurization means 12, to the pressure vessel 1 and the gas. It is introduced into the space 14 between the heating furnace 6 and the heating furnace 6 . The reason why the startup purge line 22 is branched from the pipe line between the dust removal means 11 and the desulfurization means 12 is as follows. In other words, H ₂ S in the exhaust gas at startup
is mostly _SO
If H ₂ S is supplied to the desulfurization means 12, not only the catalyst packed therein may deteriorate, but also the gas pressure will decrease due to passing through the desulfurization means 12. This is because it is appropriate to branch the air before passing through the dust removal means 11 (if it does not pass through the dust removal means 11, dust will be brought into the space 14, so naturally it must pass through the dust removal means 11).

Since the residual O ₂ concentration of the exhaust gas sent to the space 14 from the startup purge line 22 is sufficiently low, this exhaust gas is practically no different from inert gas. Exhaust gases other than those sent to the space 14 are sent to the flare stack 24 through the bypass line 22' during startup.
sent to.

With this gas, the space 14 between the pressure vessel 1 and the gasification furnace 6 is purged, and this space 14 is made inert. The exhaust gas is discharged into the atmosphere from the flare stack 24 through the purge line 23 during startup. A safety valve 25 is provided in the line 23 to regulate the pressure within the space 14.

After the temperature of the gasifier 6 becomes sufficiently high, charging of the coal 19 to the gasifier 6 is started. First, coal 19 is put into the combustor 3 and combustion is performed, and at the same time, the starting fuel 21 is gradually reduced. Around the time when the supply of startup fuel 21 is stopped, coal 19 is charged into the diffuser 4 and gasification is started.

Gas with a low calorific value at the initial stage of gasification is incinerated in the flare stack 24 via the dust removal means 11 and the desulfurization bypass line 22', or after passing through the desulfurization means 12, it is passed through the produced gas incineration line 26 and sent to the flare stack 24. be guided. After starting gasification,
The startup purge lines 22 and 23 are closed.

When the gasification progresses and gas with sufficient calorific value is obtained, the shutoff valve 27 and regulating valve 28 are opened.
It is sent to the combustor of the gas turbine 13. At the same time, the generated gas incineration line 26 is closed, the differential pressure control line 15 is opened, and the compressor 1
6. A part of the purified gas is injected into the space 14 through the accumulator 17 and the control valve 18, and the pressure in the space 14 is controlled. Note that _N2 for backup can be supplied to the space 14 from a line 29.

In addition, if a forced circulation type flue evaporator 7 is placed at the outlet of the gasifier main body 6 instead of installing a direct superheater 8 as shown in Fig. 1, this part can absorb sufficient heat. As a result, the inlet gas temperature of the downstream superheater 8 can be cooled down to an appropriate temperature. Therefore, even when the starting fuel 21 is used, the metal of the superheater 8 can be sufficiently protected, unlike conventional Cooling by water injection as in the equipment becomes unnecessary.

Furthermore, as shown in FIG. 1, a pressure regulating safety valve 25 is provided at the top of the pressure vessel 1, so that the pressure vessel 1 can be completely protected.

Note that when the device is stopped for digestion, it can be operated safely by basically following the procedure described above when starting up.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the combined coal gasification device of the present invention, and FIG. 2 is a diagram showing a conventional similar device.

Claims (1)

[Claims] 1. In a coal gasification combined cycle power generation system in which combustible gas generated in a coal gasifier arranged in a pressure vessel is sent to a gas turbine via a dedusting means and a desulfurization means, starting fuel is supplied to the coal gasifier. a bypass line for branching and extracting gas from a pipe line between the dedusting means and the desulfurization means and guiding it to the flare stack; and a purge line for guiding it into the pressure vessel; A discharge line leading to the flare stack is provided, and gas is branched and extracted from a pipe line between the desulfurization means and the gas turbine, and the gas is guided into the pressure vessel via a combustion line leading to the flare stack, a compressor, and an accumulator. A coal gasification complex device characterized by being equipped with a pressure control line.