CN1030004C - Method of operating gas turbine unit - Google Patents

Abstract

The present invention relates to a method for operating a gas turbine set. The gas turbine set comprises a combustion chamber, a high-pressure turbine driven by the air of the combustion chamber, a low-pressure turbine driven by the air of the high-pressure turbine, a device for controlling air supply from the high-pressure turbine to the low-pressure turbine, a low-pressure air compressor driven by the low-pressure turbine, and a high-pressure air compressor connected with the low-pressure air compressor in series, wherein the high-pressure air compressor is driven by the high-pressure turbine to supply pressurized air to the combustion chamber; the high-pressure air compressor is used for controlling the air state in the upper stream of the low-pressure turbine so as to regulate the effective power of the gas turbine set.

Description

Method of operating gas turbine unit

The present invention relates to the operating method of gas turbine group.

This unit comprises a firing chamber, a high pressure turbine that gas drove and the low-pressure turbine that exhaust drove that comes out by high pressure turbine that comes out by the firing chamber, be used for controlling by the device of high pressure turbine to the low-pressure turbine air feed, and low pressure compressor that drives by low-pressure turbine, drive the high-pressure compressor that is used for to the firing chamber pressurised air with one with the low pressure compressor serial connection and by high pressure turbine, the useful horsepower of gas turbine group can be regulated the control of the upstream gas state of low-pressure turbine by this device.

A kind of power plant of being made up of gas turbine and steam turbine are disclosed among the SE387703; A kind of birotary turbine scheme with middle cooling, backheat is disclosed among the SE425573.

CH-A-210,657 have also narrated above-mentioned the sort of gas turbine group.This prior art unit also comprises a middle-pressure turbine between high pressure turbine and low-pressure turbine, be supplied to gas turbine group so that reclaim useful horsepower from the axle of middle-pressure turbine from the total output of firing chamber output, unique purposes of high pressure turbine is the operate high pressure gas compressor.

In swiss patent specification, there are not particular about the gas turbine group operating temperature; Only only point out temperature when relating to device, but this device comprises the rotating vane sheet, the air feed in order to the control low-pressure turbine allegedly operates in low temperature range, promptly 200 ℃.Also have, in patent specification, do not mention the efficient of unit.Yet, can expect that efficient is low, because the invention epoch of this prior art gas turbine group are in the '30s latter stage, efficient can not surpass 30% when adopting an interstage cooler and a recuperator.

Yet, if well-known be that the efficient of more modern gas turbine group is about 30 to 35%(usually and ignores and use an interstage cooler, the back efficient that can raising of recuperator or the like).It is that the exhaust of unit has quite high temperature (almost at 500 ℃) when escaping to environment again by flue and so on that efficient is put forward not high reason.This exhaust also contains a large amount of air, and they are by the gas compressor supply, but never is utilized in burning.

In order to improve the useful horsepower of gas turbine group, this gas turbine group is made up of turbine driven gas compressor a turbo machine and, the someone advises being used to be supplied to the burning of firing chamber fuel from all air of gas compressor for a long time, and by producing steam in the pipe in the firing chamber, from the gas cooling of firing chamber to about 450 ℃ temperature.Steam turbine of steam driven.In this prior art system, this so-called Wei Luokesi (Velox) system, total useful horsepower is to take from steam-powered steam turbine, and is supplied to the gas of gas turbine to be in a quite low temperature from the firing chamber, the only enough gas compressors of operating of the power that is produced.It is about 38% that efficient is increased to, but need a sizable firing chamber, this means and strengthened plant investment.

The purpose of this invention is to provide the composite set that uses a compactness, it is a kind of gas turbine installation, it has gas turbine and steam turbine in the Wei Luokesi system, and obtain higher efficient and utilize all gas compressor air to burn, for this purpose, above-mentioned this method has the following characteristics that will say.So this useful horsepower is not to take from as the said middle-pressure turbine of swiss patent specification, but partly takes from a high pressure turbine of permanent rotating speed basically, partly takes from steam turbine.Because high pressure turbine and the high-pressure compressor that links to each other all with permanent rotating speed driving basically, have lowered the danger of aspirating in low pressure compressor.

According to the present invention, a kind of method of operating gas turbine group is provided, unit comprises a firing chamber, the high pressure turbine of the gas-powered of an origin spontaneous combustion chamber, with one by low-pressure turbine from the gas-powered of high pressure turbine, be used for controlling from the device of high pressure turbine to the low-pressure turbine supply gas, with a low pressure compressor that drives by low-pressure turbine, and high-pressure compressor that is connected in series and gives with pressurised air the firing chamber with low pressure compressor by the high pressure turbine driving, the gaseous state of the useful horsepower mat said apparatus control low-pressure turbine upstream of gas turbine group is regulated, with the gas supply of control from the high pressure turbine to the low-pressure turbine, reclaim the useful horsepower of gas turbine group from the high pressure turbine of permanent rotating speed basically, and the gas temperature that is supplied to high pressure turbine is kept substantial constant and irrelevant with the useful horsepower that reclaims from gas turbine group, it is characterized in that: nearly all air that transfers to the firing chamber from gas compressor is used to burning the firing chamber, the gas that is produced is cooled to maximum allowable operating temperature (M.A.O.T.) corresponding to high pressure turbine by the water generates steam by gas heating, is used for gas-turbine from the resulting steam power of the cooling of generation gas.

Use the raising of the total efficiency that method of the present invention obtains approximately can reach 41%, in addition, this efficient can keep substantially constant in main load range, and this is owing to be supplied to the gas temperature of high pressure turbine to keep substantially constant.

The present invention will be described in more detail with reference to the accompanying drawings, wherein:

Fig. 1 is a skeleton diagram of implementing the gas turbine installation of the inventive method,

Fig. 2 is the section axial sectional drawing of gas turbine installation turbo machine part.

Referring to Fig. 1, shown gas turbine installation comprises a gas turbine group, it has a connection high-pressure compressor 11 and generator 12 high pressure turbine 10 in order to output useful horsepower from unit, and the low-pressure turbine 13 of a connection low pressure compressor 14.Between high pressure turbine and low-pressure turbine, have adjustable link, this link is to make blade ring in this example, it has adjustable (rotatable) blade 15, Fig. 2, each blade pass is crossed arm 16 and is connected on the ring 17, ring 17 can rotate by control piece 18, and part 18 is formed the power control member of gas turbine group.

The rotatable blade of mat, expansion and the relation between the expansion in the low-pressure turbine in the high pressure turbine are controlled, thisly produce when being controlled at low flowing loss, thereby the efficient that is better than other control patterns is provided, promptly along separate routes or chock plate control.

Firing chamber 19(burner hearth) be connected to high pressure turbine with to this turbo machine air feed by its gas outlet, and low-pressure turbine and its serial connection.Low-pressure turbine connects flue, and it is represented with arrow 20.The air intlet of firing chamber connects the high-pressure compressor of supply combustion-supporting air.High-pressure compressor and low pressure compressor serial connection, it is as shown in arrow 21 that the latter obtains air from environment.

Pipe and/or pipe box are being installed shown in helix 22 in the firing chamber, and it is included in the steam-return line, and this loop also comprises a steam turbine 23, and its connects a generator and the condenser 25 in order to output useful horsepower.

In this fundamental system, can select the device that increases in addition.Like this, the interstage cooler 26 of an outside is installed between low pressure compressor and the high-pressure compressor, also has the interstage cooler 27 of an inside to be installed between air in the gas compressor loop and the condensation product (water supply) from condenser and does heat exchange.The air temperature of going to high-pressure compressor is owing to middle cooling reduces, and is preheated in the interstage cooler 27 in inside simultaneously to the water supply of burner hearth.

Also have a vapor economizer 28 to be used as a heat exchanger, be installed in and supply water and lead to the water supply of leading to the firing chamber with preheating between the exhaust of flue.

Recuperator 29 be installed in low-pressure turbine outlet pipe and between the firing chamber air intlet pipe of high-pressure compressor with by heating the gas compressor air with the heat exchange of exhaust, when gas turbine group is driven under sub load, when may be too low from the air temperature of high-pressure compressor, it be favourable doing like this.

One again heating circuit 30 be installed between steam turbine and the firing chamber so that improve the efficient of steam flow.

As special improvement, steam is released to be same as the pressure that exists in the firing chamber from steam turbine, and is injected in the firing chamber shown in 31, to reduce the oxious component from the gas of firing chamber output.Water is supplied with condenser by an outside shown in 32 for the source, the steam that is drawn out of with compensation.

The operation of above-mentioned gas turbine installation is mainly as follows, the combustion gas that produces in the firing chamber is cooled to the Maximum operating temperature of high pressure turbine by steam-return line, promptly 950 ℃, be provided to high pressure turbine again, under the predetermined gaseous state (pressure and temperature) of high pressure turbine input side, operate with the rotating speed of substantial constant.The exhaust that comes from high pressure turbine is supplied to low-pressure turbine by rotatable blade, and rotatable blade is adjustable so that existing load and air displacement are complementary.The combustion-supporting air of these two gas compressor output pressurizations is given the firing chamber.Useful horsepower part is by generator 12 outputs that directly driven by high pressure turbine, and part is by generator 24 outputs that driven by steam-return line, and this steam-return line is handled from heat that gas reclaims taking place to reduce temperature.

Because the gaseous state of control high pressure turbine upstream, with owing to directly reclaim useful horsepower with permanent rotating speed basically from high pressure turbine, gas turbine installation just obtains higher than before total efficiency, promptly be approximately 41%, this situation can also be by optionally using an interstage cooler, a recuperator, vapor economizer or the like and further being improved.

In when drop load, if promptly generator 12 and electrical network lose synchronously, the rotating speed of high pressure turbine 10 must be controlled to prevent the too high hypervelocity of turbine shaft.This is finished by adjusting vane 12, and this is necessary for the rotor that the makes low-pressure turbine institute of stopping, and it increases the pressure of the upstream of low-pressure turbine 13 and makes the pressure of high pressure turbine 10 reduce and the heat drop also reduction of power output.The drop of pressure on low-pressure turbine 13 and heat meanwhile will increase, but the decrease in efficiency of stopping and to cause owing to low pressure turbine rotor will be constant basically from the power of low-pressure turbine output.Like this, can prevent unallowed hypervelocity and generate electricity function after several seconds once more and synchronized, this is to reach by rotating speed to the desirable value with blade adjustments high pressure turbine 10.

Claims (2)

1, a kind of method of operating gas turbine group, unit comprises a firing chamber, the high pressure turbine of the gas-powered of an origin spontaneous combustion chamber, with one by low-pressure turbine from the gas-powered of high pressure turbine, be used for controlling from the device of high pressure turbine to the low-pressure turbine supply gas, with a low pressure compressor that drives by low-pressure turbine, and high-pressure compressor that is connected in series and gives with pressurised air the firing chamber with low pressure compressor by the high pressure turbine driving, the gaseous state of the useful horsepower mat said apparatus control low-pressure turbine upstream of gas turbine group is regulated, with the gas supply of control from the high pressure turbine to the low-pressure turbine, reclaim the useful horsepower of gas turbine group from the high pressure turbine of permanent rotating speed basically, and the gas temperature that is supplied to high pressure turbine is kept substantial constant and irrelevant with the useful horsepower that reclaims from gas turbine group, it is characterized in that: nearly all air that transfers to the firing chamber from gas compressor is used to burning the firing chamber, the gas that is produced is cooled to maximum allowable operating temperature (M.A.O.T.) corresponding to high pressure turbine by the water generates steam by gas heating, is used for gas-turbine from the resulting steam power of the cooling of generation gas.

2, as the method in the claim 1, it is characterized by in the above-mentioned control of when drop load mat and be supplied to the device of low-pressure turbine gas from high pressure turbine, the rotor of low-pressure turbine is stopped.

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