CN110631050B - A mixed heating system and method for gas turbine synthesis gas fuel of IGCC power station - Google Patents

Abstract

The invention discloses a mixed heating system and a method for synthetic gas fuel of a gas turbine of an IGCC power station, comprising the following steps: the system comprises a synthesis gas pipeline, a main steam pipeline, a first auxiliary steam pipeline, a second auxiliary steam pipeline, a heat exchanger and a mixer; the outlet of the synthesis gas pipeline is connected with the low-temperature inlet of the heat exchanger, and the low-temperature outlet of the heat exchanger is connected with the synthesis gas inlet of the synthesis gas steam mixer; the outlet of the main steam pipeline is divided into two paths: a first water vapor secondary conduit, a second water vapor secondary conduit; the first steam auxiliary pipeline is connected with a steam inlet of the synthesis gas steam mixer; the second steam auxiliary pipeline is connected with a high-temperature inlet of the heat exchanger; the outlet of the synthesis gas steam mixer is connected with the inlet of the combustion chamber. When the invention is operated under the condition of lower environmental temperature in winter, the white value of the synthetic gas fuel at the inlet of the burner can be adjusted, the combustion stability is improved, and the temperature of the gas at the outlet of the combustion chamber can be kept unchanged.

Description

A mixed heating system and method for gas turbine synthesis gas fuel of IGCC power station

technical field

The invention belongs to the field of gas turbines in IGCC power stations, and in particular relates to a mixed heating system and method for syngas fuel of gas turbines in IGCC power stations.

Background technique

IGCC power plant is a power generation technology that uses the synthesis gas produced by the gasification of coal and other solid fuels for the gas-steam cycle. As the fuel of IGCC, the syngas produced by the chemical reaction of coal in the gasifier mainly includes _H2 and CO. Because it contains more H ₂ , the chemical reaction speed is fast. In order to avoid the tempering phenomenon during hydrogen-rich combustion, in practice, inert gases such as water vapor are used to further dilute the synthesis gas. Although the combustion speed of the diluted syngas is reduced and tempering will not occur, when the diluted syngas is combusted, combustion oscillations, periodic drastic changes of the flame surface, and high-amplitude pressure pulsations may occur. Stabilization phenomenon, which has a serious impact on the normal operation of the gas turbine.

The gas turbine system of an IGCC power station has relatively stable combustion and can operate stably when the ambient temperature is high in summer. In winter, when the ambient temperature is lower than 0°C, the flame combustion in the combustion chamber is unstable, which is mainly manifested in the frequent occurrence of alarm signals with a pressure fluctuation greater than 80 mbar and a duration greater than 0.4 s detected by the buzzer monitoring system in the combustion chamber. Moreover, the ambient temperature has a consistent correlation with the buzzer signal, the higher the ambient temperature, the buzzer disappears; the lower the ambient temperature, the more frequent the buzzer. Frequent beeping alarms can not only lead to over-fuel switching back to fuel oil conditions or tripping events, but also may cause accidents such as cracks in the combustion chamber heat insulation tiles.

According to the operating experience, in winter when the ambient temperature is low, increasing the Wobbe value of the syngas fuel can significantly reduce the frequency of gas turbine buzzer alarm signals. However, under the condition that the fuel flow rate of syngas remains unchanged, simply increasing its Wobbe value will cause the gas at the outlet of the combustor to overheat, and there is a risk of burning the turbine blades.

Contents of the invention

The object of the present invention is to provide a mixed heating system and method for gas turbine synthesis gas fuel of IGCC power station, so as to solve the above-mentioned technical problems.

In order to achieve the above object, the present invention adopts the following technical solutions:

A mixed heating system for gas turbine synthesis gas fuel in an IGCC power station, comprising: a synthesis gas pipeline, a water vapor main pipeline, a first water vapor sub-pipe, a second water vapor sub-pipe, a heat exchanger and a mixer;

The outlet of the synthesis gas pipeline is connected to the low temperature inlet of the heat exchanger, and the low temperature outlet of the heat exchanger is connected to the synthesis gas inlet of the synthesis gas steam mixer;

The outlet of the main steam pipe is divided into two paths: the first water vapor auxiliary pipe and the second water vapor auxiliary pipe; the first water vapor auxiliary pipe is connected to the water vapor inlet of the synthesis gas steam mixer; the second water vapor auxiliary pipe is connected to High temperature inlet of heat exchanger;

The outlet of the syngas-steam mixer is connected to the inlet of the combustion chamber.

Further, it also includes a bypass water vapor pipe; the inlet of the bypass water vapor pipe is connected to the first water vapor auxiliary pipe, and the outlet is connected to the inlet of the combustion chamber; the water vapor pipe is provided with a first regulating valve.

Further, a second regulating valve is provided on the first water vapor auxiliary pipeline.

Further, a third regulating valve is provided on the second water vapor auxiliary pipeline.

Further, the dust-removed and purified syngas produced by the upstream gasifier enters the syngas pipeline, firstly heats up with the second water vapor sub-pipe in the heat exchanger, and then enters the mixer to be connected with the second water vapor sub-pipe The water vapor is mixed, and finally sent to the burner in the combustion chamber for combustion.

A mixed heating method for gas turbine synthesis gas fuel in an IGCC power station, comprising:

The water vapor in the water vapor main pipeline 2 is medium-pressure steam, the pressure is about 4.85Mpa, and the temperature is 260°C. The synthesis gas in the synthesis gas pipeline 1 is the dust-removed and purified synthesis gas produced by the upstream gasifier.

First, the synthesis gas in the synthesis gas pipeline 1 with a pressure of 2.5Mpa and a temperature of 100°C passes through the heat exchanger to exchange heat with water vapor at a pressure of 4.85Mpa and a temperature of 260°C in the second steam sub-pipeline to increase the temperature of the synthesis gas to 200°C; The heated synthesis gas is mixed with the water vapor in the first water vapor sub-pipeline in the mixer, and the mixed synthesis gas enters the combustion chamber to participate in combustion.

Further, in the winter operation mode, the first regulating valve on the bypass steam pipeline is opened, so that the water vapor mixed with the syngas in the first steam sub-pipeline is correspondingly reduced, and the Wobbe value at the outlet of the mixer is correspondingly increased ; At the same time, the water vapor in the corresponding bypass water vapor pipe directly enters the combustion chamber, mixes with the high-temperature gas generated by the burner combustion, and reduces its temperature, so that the outlet temperature of the combustion chamber remains unchanged.

Further, the water vapor flow rate in the bypass water vapor pipeline is 10%-20% of the water vapor flow rate in the first water vapor auxiliary pipeline.

Compared with the prior art, the present invention has the following beneficial effects: the present invention proposes a hybrid heating system for syngas fuel in an IGCC power station, which can adjust the temperature of the syngas fuel at the burner inlet when operating in winter when the ambient temperature is low. The Wobbe value improves the stability of combustion and ensures that the gas temperature at the outlet of the combustion chamber remains unchanged.

In winter, when the ambient temperature is low and the buzzer alarm of the gas turbine is relatively frequent, the first regulating valve of the bypass is opened, so that a part of the inert gas such as water vapor does not directly participate in the mixing and dilution of the syngas, and directly enters the combustion chamber to mix with the high-temperature gas; The lack of a part of the inert gas mixed with the syngas in the road will correspondingly increase the Wobbe value entering the combustion chamber of the gas turbine, thereby improving the combustion stability. The water vapor in the bypass water vapor pipe finally enters the combustion chamber, thereby ensuring that the gas temperature at the exit of the combustion chamber remains unchanged and eliminating the risk of burning the turbine blades.

The invention can bypass the water vapor volume of the water vapor pipe through the opening degree of the flow regulating valve according to the change of the ambient temperature. The lower the ambient temperature in winter, the larger the valve opening; the higher the ambient temperature in summer, moderately reduce the valve opening until the valve is closed.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is a structural schematic diagram of a hybrid heating system of a gas turbine syngas fuel in an IGCC power station according to the present invention.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

The following detailed descriptions are all exemplary descriptions, and are intended to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the art to which the present application belongs. Terms used in the present invention are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention.

Please refer to shown in Fig. 1, the present invention provides a kind of mixed heating system of syngas fuel of IGCC power station, comprise syngas pipeline 1, water vapor main pipeline 2, first water vapor secondary pipeline 3, second water vapor secondary pipeline 4, Bypass steam pipeline 5, synthesis gas heating heat exchanger 6 and synthesis gas steam mixer 7.

The outlet of the synthesis gas pipeline 1 is connected to the low-temperature inlet of the heat exchanger 6 , and the low-temperature outlet of the heat exchanger 6 is connected to the synthesis gas inlet of the synthesis gas-steam mixer 7 . The outlet of the main water vapor pipeline 2 is divided into two paths: the first water vapor secondary pipeline 3 and the second water vapor secondary pipeline 4; the first water vapor secondary pipeline 3 is connected to the water vapor inlet of the synthesis gas steam mixer 7; The outlet of the steam mixer 7 is connected to the inlet of the combustion chamber 8 . The second steam sub-pipe 4 is connected to the high-temperature inlet of the heat exchanger 6 .

The inlet of the bypass water vapor pipeline 5 with the first regulating valve is connected to the first water vapor sub-pipe 3 , and the outlet is connected to the inlet of the combustion chamber 8 . By closing/opening the first regulating valve, it can be controlled whether the bypass water vapor pipe 5 works to divert the water vapor in the first water vapor auxiliary pipe 3 .

The first water vapor secondary pipeline 3 is provided with a second regulating valve, and the second water vapor secondary pipeline 4 is provided with a third regulating valve. By adjusting the openings of the second regulating valve and the third regulating valve, the first water vapor can be adjusted. The flow ratio of the steam sub-pipe 3 and the second water vapor sub-pipe 4.

The water vapor in the water vapor main pipeline 2 is medium-pressure steam, the pressure is about 4.85Mpa, and the temperature is 260°C. The syngas in the syngas pipeline 1 is the dedusted and purified syngas produced by the upstream gasifier, with a pressure of about 2.5Mpa and a temperature of about 100°C.

First, the syngas pipeline 1 needs to raise its own temperature to about 200°C through the heat exchanger 6, and then mix with the water vapor in the first water vapor sub-pipe 3 in the mixer 7, and the mixed syngas can enter the combustion chamber 8 Participate in burning. This part is the synthesis gas fuel mixing heating system of the gas turbine of the IGCC power station. Its main purpose is to adjust the Wobbe value of the syngas.

The Wobbe value is an indicator of the interchangeability of different fuels. The same Wobbe value means that the released heat energy is guaranteed to be the same when the operating conditions such as pressure and valve opening are kept constant, which is conducive to the stable operation of the gas turbine. Under working conditions. Therefore, in order to keep the outlet temperature of the combustion chamber constant, the ratio of water vapor to syngas should be adjusted according to the predetermined Wobbe value _Wsp . The Wobbe value is defined as the ratio of the fuel high calorific value H _sg to the square root of its relative density, and the reference density is usually the density ρ _air of air under the same conditions, as shown in the following formula:

Among them, ρ _sg is the density of syngas.

Generally speaking, the higher the Wobbe value of the syngas fuel, the better its combustion stability, but it is easy to cause the outlet temperature of the combustion chamber to overheat.

Then, under the stable operation condition of the gas turbine, in order to ensure that the outlet temperature of the combustion chamber of the gas turbine remains unchanged, it is first necessary to ensure that the amount of pure syngas entering the combustion chamber and the amount of water vapor are in an appropriate ratio, and the total amount must not exceed Change. That is to ensure that the synthesis gas flow rate in the synthesis gas pipeline 1 is constant, and the total amount of water vapor in the first water vapor sub-pipeline 3 and the bypass water vapor pipeline 5 is constant.

When reducing or increasing the amount of water vapor in the bypass water vapor pipeline 5 , the amount of water vapor in the first water vapor secondary pipeline 3 is correspondingly increased or decreased. Generally, the amount of water vapor in the bypass steam pipe 5 is about 10% to 20% of the water vapor in the first secondary water vapor pipe 3 .

Its operation mode is as follows: firstly, it is ensured that the total amount of corresponding gas in the synthesis gas pipeline 1 and the water vapor main pipeline 2 remains unchanged.

When the ambient temperature is low in winter, it is necessary to open the valve on the bypass steam pipeline 5 so that the water vapor mixed with the first steam sub-pipe 3 and the synthesis gas is correspondingly reduced, and the Hua at the outlet of the mixer 7 is correspondingly increased. The white value ensures the combustion stability of the combustion chamber. At the same time, a part of water vapor in the corresponding bypass water vapor pipe 5 directly enters the combustion chamber 8, mixes with the high-temperature gas generated by the burner combustion, and lowers its temperature to ensure that the outlet temperature of the combustion chamber remains unchanged.

When the ambient temperature is high in summer, close the valve on the bypass water vapor pipeline 5, so that the water vapor in the main steam pipeline 2 is used for heating the synthesis gas through the second steam auxiliary pipeline 4, and all the rest are in the mixer. 7 and mixed with synthesis gas.

It can be known from common technical knowledge that the present invention can be realized through other embodiments without departing from its spirit or essential features. Accordingly, the above-disclosed embodiments are, in all respects, illustrative and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are embraced by the present invention.

Claims (6)

1. a mixed heating system of IGCC power plant gas turbine synthesis gas fuel, is characterized in that, comprises: synthesis gas pipeline (1), water vapor main pipeline (2), the first water vapor secondary pipeline (3), the second steam Auxiliary pipeline (4), heat exchanger (6) and mixer (7); The outlet of the synthesis gas pipeline (1) is connected to the low temperature inlet of the heat exchanger (6), and the low temperature outlet of the heat exchanger (6) is connected to the synthesis gas inlet of the synthesis gas steam mixer (7); The outlet of the main steam pipeline (2) is divided into two paths: the first secondary steam pipeline (3), the second secondary steam pipeline (4); the first secondary steam pipeline (3) is connected to the synthesis gas steam mixer (7) steam inlet; the second water vapor secondary pipeline (4) connects the high temperature inlet of heat exchanger (6); The outlet of the synthesis gas steam mixer (7) is connected to the inlet of the combustion chamber (8); Also includes a bypass water vapor pipe (5); the inlet of the bypass water vapor pipe (5) is connected to the first water vapor secondary pipe (3), and the outlet is connected to the inlet of the combustion chamber (8); on the bypass water vapor pipe (5) A first regulating valve is provided; The dust-removed and purified syngas produced by the upstream gasifier enters the syngas pipeline (1), is first heated in the heat exchanger (6) with the second water vapor sub-pipeline (4), and then enters the mixer ( 7) mix with the water vapor of the first water vapor sub-pipeline (3), and finally send it into the burner of the combustion chamber (8) to participate in combustion. 2. The mixed heating system of a kind of IGCC power station gas turbine syngas fuel according to claim 1, characterized in that, the first water vapor secondary pipeline (3) is provided with a second regulating valve. 3. The mixed heating system of a kind of IGCC power station gas turbine syngas fuel according to claim 2, characterized in that a third regulating valve is arranged on the second water vapor sub-pipeline (4). 4. a hybrid heating method of IGCC power station gas turbine synthesis gas fuel, characterized in that, based on the hybrid heating system of a kind of IGCC power station gas turbine synthesis gas fuel described in any one of claims 1 to 3, comprising: The water vapor in the main steam pipeline (2) is medium-pressure steam with a pressure of 4.85Mpa and a temperature of 260°C; the synthesis gas in the synthesis gas pipeline (1) is the dedusted and purified synthesis gas produced by the upstream gasifier ; First, the synthesis gas in the synthesis gas pipeline (1) with a pressure of 2.5Mpa and a temperature of 100°C passes through the heat exchanger (6) to exchange heat with water vapor at a pressure of 4.85Mpa and a temperature of 260°C in the second water vapor sub-pipeline (4), Increase the temperature of the syngas to 200°C; the heated syngas is mixed with the water vapor in the first water vapor sub-pipeline (3) in the mixer (7), and the mixed syngas enters the combustion chamber (8) to participate in combustion. 5. the mixed heating method of a kind of IGCC power station gas turbine syngas fuel according to claim 4, is characterized in that, under winter operation pattern, opens the first regulating valve on the bypass steam pipeline (5), makes the first The water vapor mixed with the synthesis gas in a water vapor auxiliary pipe (3) is correspondingly reduced, and the Wobbe value at the outlet of the mixer (7) is correspondingly increased; at the same time, the water vapor in the corresponding bypass water vapor pipe (5) directly enters the combustion chamber The chamber (8) is mixed with the high-temperature gas produced by the burner combustion, and its temperature is lowered so that the outlet temperature of the combustion chamber remains unchanged. 6. the mixed heating method of a kind of IGCC power station gas turbine syngas fuel according to claim 5, is characterized in that, in the bypass water vapor pipeline (5), the water vapor flow rate is in the first water vapor sub-pipeline (3) 10% to 20% of the water vapor flow.

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