JPS63280824A - Operation method for methanol reforming type gas turbine - Google Patents

Abstract

PURPOSE:To attempt a stable combustion by feeding the specific ratio quantity of air for combustion as air containing steam along with feeding steam- containing gas as methanol reforming gas, and feeding to a burner the rest of air containing no steam together with methanol gas. CONSTITUTION:Methanol and water gasify as they pass inside the exhaust duct 1 of a turbine 10, and when methanol gas has reached a predetermined temperature, part of its is fed to the burner 5 of the gas turbine as a pilot burner fuel by means of a branching valve A. Also, the greater part of the remainder is introduced to a reformer 2 after being made to mix with steam separated by means of a branching valve B. Here, it is contacted with a reforming catalyst and reformed to a reforming gas and then fed to the burner 5. Also, the remaining steam at the branching valve B is mixed at a mixer 7 with the air of 80vol.% of air for combustion from a compressor 6 and fed to the burner 5, while the remaining air for combustion is arranged so as to be fed to the burner 5 as air which does not contain steam together with methanol gas.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention uses a low-calorie mixed gas in which both the methanol reformed gas as fuel and the air for its combustion contain a large amount of water vapor. The present invention relates to a method of operating a highly energy-efficient methanol reforming gas turbine that can perform combustion.

[Conventional technology]

Conventionally, raw materials methanol and water are preheated and gasified using the waste heat of a gas turbine, and reformed gas is obtained by heating them to a predetermined temperature and supplying them to a reformer for reaction. A method of operating a methanol reforming gas turbine that uses this reformed gas as fuel for the main burner of the turbine is well known (for example, JP-A-61-1
49532).

The methanol reformed gas obtained by using the waste heat of this gas turbine contains a large amount of water vapor, and the combustion air also contains a large amount of water vapor, making it difficult to achieve stable combustion.
The turbine could not be operated satisfactorily and stably.

In addition, the type and amount of reformed fuel components (heat generation IT) in the methanol reformed gas fluctuates as the load on the gas turbine changes, which impedes stable combustion of the methanol reformed gas. However, in the operation of a gas turbine that utilizes waste heat efficiently, controlling the amount of water vapor in the combustion air as well as the methanol reformed gas poses an obstacle to improving thermal efficiency and output. This is not desirable in terms of equipment costs and turbine operation management.

Therefore, if both methanol reformed gas and combustion air can be used as they are without being affected by the amount of water vapor contained in them, it would be possible to operate a methanol reforming turbine that utilizes the waste heat of the turbine. Needless to say, it is extremely advantageous from an energy and operational standpoint.

The present inventors have proposed that even though the methanol reformed gas and the combustion air each contain a large amount of water vapor, a small amount of air that is substantially free of water vapor is also supplied to the combustor of the gas turbine. For example, we discovered that stable combustion can be achieved, but when the fluctuations in the gas turbine load become large, stable and continuous combustion cannot be achieved, and in some cases combustion may be interrupted, which means that maintenance Focusing on the loss of flammability, the present invention was discovered through extensive research.

[Purpose of the invention]

The object of the present invention is not only the above-mentioned methanol reformed gas, but also
Even if the combustion air contains a large amount of water vapor, it not only allows stable combustion and turbine operation, but also maintains flame stability against gas turbine load fluctuations and lasts for a long time. The object of the present invention is to provide a method that enables stable combustion, that is, operation of a gas turbine.

[Structure of the invention]

An object of the present invention is to supply a gas containing water vapor as the methanol reformed gas and to combust the methanol reformed gas and combustion air when the fuel is supplied to the combustor of a gas turbine and combusted. At least 80 volume χ of the air for combustion is supplied with water vapor-containing air, and for less than 20 volume % of the combustion air, air containing substantially no water vapor is supplied, and methanol gas is supplied, This can be achieved by forcing.

That is, the feature of the present invention is to stably combust a mixed gas of methanol reformed gas, which is a fuel containing a large amount of water vapor, which cannot normally be stably combusted, and combustion air, which also contains a large amount of water vapor. When such a low-calorie mixed gas is used as fuel, it has excellent flame stability against load fluctuations in the gas turbine and enables stable operation of the gas turbine over long periods of time. Combustion air that does not contain air is mixed with the reformed gas, and this mixed gas is fed to the primary combustion zone, which is said to determine the combustion characteristics of the turbine's combustor, and further heated by the turbine's exhaust gas. Methanol gas is supplied as fuel for the pilot burner in order to maintain flame stability in the combustor of the turbine.

In the present invention, the methanol reformed gas containing a large amount of water vapor is produced using the waste heat of a turbine, and heated to a predetermined temperature, usually in a temperature range of 200°C to 300°C, to be heated to a combustor of the turbine. The combustion air supplied to the combustor of the turbine is also preferably heated to a predetermined temperature, usually in the range of 450°C to 550°C, using the waste heat of the turbine. The methanol gas supplied as fuel for the pilot burner is heated to at least 400°C, preferably at 45°C, using the waste heat of the turbine.
It is supplied as a high temperature gas in the range of 0°C to 600°C.

(Example) Hereinafter, an example of the present invention will be specifically described based on the drawings.

The figure is a flowchart diagram for explaining a method of operating a gas turbine according to the present invention.

In the figure, methanol and water move in the directions of the arrows, are introduced into the exhaust duct 1 of the turbine 10, and are gasified, and then the vaporized methanol gas and water vapor are further transferred into the exhaust duct 1. It is heated and raised in temperature. When the methanol gas reaches a predetermined temperature, a portion of the gas is separated at branch valve A as fuel for a pilot burner, which will be described later.The majority of the gas is separated from branch valve B and becomes steam heated in a separate exhaust duct. mixed with. This mixed gas is further led to an exhaust duct, heated to a temperature range of approximately 300 to 350°C, and introduced into a reformer filled with a reforming catalyst, where a chemical reaction is caused to cause the reformed gas to will be converted to

The mixing ratio of methanol gas and water vapor is within the range of 20 to 50 volume χ of methanol gas and 80 to 50 volume χ of water vapor.

The methanol reformed gas that has been reformed in the reformer 2 and has increased calories is sent as is to the combustor 5 of the gas turbine as fuel. The permissible water vapor content of this methanol reformed gas is usually at least 30 volumes χ, preferably 1
~20 capacity χ, allowing the inclusion of a large amount of water vapor.

In addition, as shown in the figure, a part of the raw methanol gas extracted by the branch valve A before being supplied to the reformer 2, preferably 20 to 40% by volume of the raw methanol gas, is exhausted to the exhaust gas. At least about 5
The temperature of the fuel is raised to 00°C, and the fuel is supplied to the combustor 5 of the gas turbine as pilot burner fuel.

On the other hand, the remaining water vapor, a part of which is separated as the methanol reformed gas raw material at the branch valve B, is mixed in the mixer 7 with at least 80 volumes χ of the combustion air from the compressor 6. This water vapor-containing air is led to the exhaust duct 1, heated to about 450°C to 500°C, and used as secondary combustion air.
In addition to being supplied to the secondary combustion region of the combustor 5 of the turbine 10, it can also be efficiently used for cooling the inner cylinder of the combustor 5.

Further, the compressed air that does not substantially contain water vapor is separated by a branch valve C, further guided into the exhaust duct 1, heated to a temperature range of about 450 to 500°C, and then transferred to the combustor 5. Supplied to the primary combustion zone.

Note that the permissible amount of water vapor contained in the water vapor-containing combustion air supplied to the combustor 5 is 30 volumes or less, preferably 1
~5 volume χ, similar to the methanol reformed gas of the fuel,
Allows large amounts of water vapor to be contained.

〔Example〕

In the figure, the combustor 5 contains 20× water vapor.
25Kg/S of 30℃ high-temperature methanol reformed gas and 222Kg/S of 496℃ high-temperature air containing 5χ of water vapor.
S, high temperature air of 496℃ that does not contain water vapor at 52
Kg/S and 500°C high temperature methanol gas 2.
Each was supplied in an amount of 5 kg/s, and the gas turbine was operated. As a result, stable combustion was obtained and stable operation was achieved even when the gas turbine load fluctuated.

On the other hand, when water vapor was mixed into the primary combustion air during the operation of the gas turbine, the stability of the flame decreased, causing oscillating combustion and misfire, and the turbine stopped operating.

Furthermore, when the supply of methanol gas to the pilot burner was stopped, the flame holding function deteriorated and the flame became unstable, making it difficult to continue combustion unless the turbine load fluctuation was suppressed within an extremely limited range. It turned out to be.

〔Effect of the invention〕

According to the present invention, the following excellent effects can be obtained.

(1) Stable combustion of methanol reformed gas, which contains a large amount of water vapor and low calorific value and cannot normally be combusted stably as it is, using combustion air that also contains a large amount of water vapor. be able to. In other words, when operating a gas turbine that utilizes the waste heat of the gas turbine, the amount of water vapor contained in the methanol reformed gas and the combustion air can be used without concern, and there is no need to particularly control them.

(2) Even if the air contains a large amount of moisture or water vapor,
Since it can be used for combustion, it is possible to operate the turbine within a wide range from startup to rated operation.

(3) As the fuel for the pilot burner, methanol gas obtained by gasifying a part of the raw methanol is used, and the flame stability of the turbine is improved. It is possible to prevent combustion from being interrupted due to turbine load fluctuations during use, and stable operation over a long period of time is possible.

(4) Since it allows the inclusion of a large amount of water vapor, the temperature of the combustion vessel's inner cylinder can be kept at a low temperature.

(5) The waste heat of the gas turbine can be utilized to the maximum extent, and the power generation (energy) efficiency using the turbine can be improved.

[Brief explanation of the drawing]

The figure is a flowchart diagram for explaining the method of operating a gas turbine according to the present invention. 1... Exhaust duct, 2... Reformer, 5... Combustor, 1O... Turbine, 11... Generator.

Claims (1)

[Claims] When methanol reformed gas and combustion air as fuel are supplied to a combustor of a gas turbine and combusted, a gas containing water vapor is supplied as the methanol reformed gas, and at least 80% by volume of the combustion air is also supplied. Methanol reforming characterized by supplying air containing water vapor, and supplying air that does not substantially contain water vapor for 20% by volume or less of combustion air, and further supplying methanol gas for combustion. How to operate a type gas turbine.