Coordination control method for improving load change rate of IGCC (integrated gasification combined cycle) unit

Abstract

The invention provides a coordination control method for improving the load change rate of an IGCC unit, and the method comprises the following steps: obtaining the operation data of the IGCC unit, and determining the linear relation between the load of a gas turbine and the load of a gasifier according to the operation data; gasification furnace parameters of the IGCC unit are obtained, and the gasification furnace load variable rate is determined according to the gasification furnace parameters; determining a gas turbine load variable rate according to the gasification furnace load variable rate; acquiring a boundary condition of the pre-engine synthesis gas pressure; and the load of the gas turbine and the load of the gasification furnace are adjusted, so that the load of the IGCC unit is adjusted. According to the coordination control method for improving the IGCC unit load change rate, the response change speed of unit loads can be improved, the performance index of a unit is improved, the front pressure limit value control of a synthesizer is increased, and the power grid requirement is met on the premise that safe operation is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation control, and in particular to a coordinated control method for improving the load change rate of an IGCC unit. Background Art

[0002] The integrated coal gasification combined cycle power generation system (IGCC) is an advanced power system that combines coal gasification technology with an efficient combined cycle. It consists of two major parts, namely the coal gasification and purification part and the gas-steam combined cycle power generation part. The main equipment of the first part includes the gasifier, air separation unit and synthesis gas purification equipment; the main equipment of the second part includes the gas turbine power generation system, waste heat boiler and steam turbine power generation system.

[0003] The coordinated control system of the IGCC unit is a system that coordinates and controls the oxygen load regulator of the gasifier and the power regulator of the gas turbine. The coordinated control system controls the gasifier and the gas turbine as a whole unit group and is part of the control system of the entire power unit. The entire control system consists of three major parts: the load control system (main control system), the conventional control system (sub-control system) and the load control object.

[0004] At present, the commonly used coordinated control method for IGCC units is the gas turbine following mode, that is, the unit load command acts on the gasifier oxygen load adjustment system, and the gas turbine control engine front synthesis gas pressure is maintained at 2.5MPa. Due to the large hysteresis of the gasification island of the IGCC unit, the gasifier load change rate is low. The coordinated control method of gas turbine following has the advantage of safe and stable unit operation, but the disadvantage is that the unit load change rate is slow and cannot meet the requirements of the grid-related AGC performance indicators. Summary of the invention

[0005] The purpose of the present invention is to provide a coordinated control method for improving the load change rate of an IGCC unit, which aims to improve the load change rate of the IGCC unit and improve the AGC performance index of the IGCC unit by optimizing the unit coordinated control strategy so that it can meet the power grid demand while ensuring safe operation.

[0006] The embodiments of the present invention are implemented by the following technical solutions:

[0007] A coordinated control method for improving the load change rate of an IGCC unit comprises the following steps:

[0008] Obtaining the operating data of the IGCC unit, and determining the linear relationship between the gas turbine load and the gasifier load based on the operating data; wherein the operating data includes the gasifier load, the actual power of the gas turbine, the actual power of the steam turbine, the calorific value of the synthesis gas, the pressure value of the synthesis gas before the unit, the lower limit value of the synthesis gas pressure, and the upper limit value of the synthesis gas pressure;

[0009] Obtaining gasifier parameters of the IGCC unit, and determining the gasifier load change rate according to the gasifier parameters;

[0010] Determine the gas turbine load change rate according to the gasifier load change rate;

[0011] Obtain the pre-machine synthesis gas pressure boundary conditions;

[0012] According to the linear relationship between the gas turbine load and the gasifier load, the gasifier load change rate, the gas turbine load change rate and the pre-syngas pressure boundary conditions, the gas turbine load and the gasifier load are adjusted to complete the adjustment of the IGCC unit load.

[0013] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects: the coordinated control method for increasing the load change rate of the IGCC unit can increase the response change speed of the unit load, improve the performance indicators of the unit, and increase the synthetic pre-machine pressure limit control, so that it can meet the power grid demand while ensuring safe operation.

[0014] Furthermore, the method for obtaining the boundary condition of the pre-syngas pressure is specifically as follows:

[0015] The upper and lower limits of the synthesis gas pressure are determined based on the change in the synthesis gas pressure before the gas turbine and the operating conditions of the gas turbine.

[0016] Further, the gas turbine load and the gasifier load are adjusted to adjust the IGCC unit load, including the following sub-steps:

[0017] Determine the actual load instruction of the unit according to the AGC instruction of the network, the upper limit value of the unit load, the lower limit value of the unit load and the unit load change rate;

[0018] Determining a first power output value according to the actual power generated by the gas turbine, the actual power generated by the steam turbine and the actual load instruction of the unit;

[0019] Determining a second power output value according to the syngas pressure value before the machine and the syngas pressure lower limit value;

[0020] taking the minimum value of the first power output value and the second power output value as the third power output value;

[0021] Determining a fourth power output value according to a syngas pressure value before the machine and an upper limit value of the syngas pressure;

[0022] taking the maximum value of the third power output value and the fourth power output value as the fifth power output value;

[0023] Determining the engine load output value according to the fifth power output value and the engine load variable rate setting value;

[0024] Determine the gasifier outlet pressure setting value according to the pre-machine synthesis gas pressure value and the pre-machine pressure setting value;

[0025] The gasifier load output value is determined according to the gasifier outlet pressure value, the gasifier outlet pressure setting value, the gas turbine actual power and the gasifier load change rate setting value.

[0026] Furthermore, the method for determining the actual load instruction of the unit is specifically as follows: the network AGC instruction, the unit load upper limit value and the unit load lower limit value are used as the unit load instruction without rate limit after high and low value judgment, and the unit actual load instruction is generated according to the unit load instruction without rate limit and the unit load change rate setting value.

[0027] Furthermore, the method for determining the first power output value is specifically as follows: taking the actual power of the gas turbine as the measured value PV of the first power regulator, and inputting it into the first power regulator of the IGCC unit; taking the value after performing a difference operation between the actual load instruction of the unit and the actual power of the steam turbine as the set value SP of the first power regulator, and inputting it into the first power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measured value PV and the set value SP through the first power regulator of the IGCC unit to generate the first power output value.

[0028] Furthermore, the method for determining the second power output value is specifically as follows: taking the pre-machine synthesis gas pressure value as the measurement value PV of the second power regulator, and inputting it into the second power regulator of the IGCC unit; taking the synthesis gas pressure lower limit value as the set value SP of the second power regulator, and inputting it into the second power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measurement value PV and the set value SP by the second power regulator of the IGCC unit to generate the second power output value.

[0029] Furthermore, the method for determining the fourth power output value is specifically as follows: taking the pre-machine synthesis gas pressure value as the measurement value PV of the third power regulator, and inputting it into the third power regulator of the IGCC unit; taking the synthesis gas pressure upper limit value as the set value SP of the third power regulator, and inputting it into the third power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measurement value PV and the set value SP through the third power regulator of the IGCC unit to generate the fourth power output value.

[0030] Furthermore, the method for determining the set value of the gasifier outlet pressure is specifically as follows: using the pre-machine syngas pressure as the measured value PV of the fourth power regulator, and inputting it into the fourth power regulator of the IGCC unit; using the pre-machine set rate as the set value SP of the fourth power regulator, and inputting it into the fourth power regulator of the IGCC unit; performing proportional operation, integral operation and differential control operation on the input measured value PV and the set value SP in the fourth power regulator of the IGCC unit, to generate the pre-machine syngas pressure constant.

[0031] Furthermore, the method for determining the gasifier load output value is specifically as follows: the gasifier outlet pressure value is used as the measured value PV of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; the pre-machine synthesis gas pressure constant is used as the set value SP of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; the actual power generated by the gas turbine is used as the feedforward value FF of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; and the gasifier load output value is generated by performing proportional operation, integral operation and differential control operation on the input measured value PV, set value SP and feedforward value FF in the fifth power regulator of the IGCC unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A flow chart of a coordinated control method for improving the load change rate of an IGCC unit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] like Figure 1 As shown, the present invention provides a coordinated control method for improving the load change rate of an IGCC unit, comprising the following steps:

[0035] The operation data of the IGCC unit is obtained, and the linear relationship between the gas turbine load and the gasifier load is determined based on the operation data; wherein the operation data includes the gasifier load, the actual power of the gas turbine, the actual power of the steam turbine, the calorific value of the synthesis gas, the pressure value of the synthesis gas before the machine, the lower limit value of the synthesis gas pressure and the upper limit value of the synthesis gas pressure; the synthesis gas generated by the gasifier is used for combustion and power generation by the gas turbine, so the higher the gasifier load, the more synthesis gas is generated, and the more synthesis gas is supplied to the gas turbine for combustion and power generation, so the gas turbine can do more work, so the gasifier load and the gas turbine load are roughly in a one-to-one linear relationship, when the gasifier load increases, the corresponding gas turbine load will also increase, when the gasifier load decreases, the corresponding gas turbine load will also decrease, and when the gasifier load remains unchanged, the corresponding gas turbine load will also remain roughly unchanged; the matching curve of the gasifier load and the gas turbine load can be obtained from the corresponding relationship, and according to this matching relationship, the gasifier load variable rate and the gas turbine load variable rate are coordinated. According to the gasifier load, syngas calorific value, syngas pressure before the gas turbine and the actual power operation data of the gasifier, the approximate corresponding relationship between the gasifier load and the gas turbine load is estimated. The syngas produced by the gasifier has a certain calorific value. The syngas calorific value used for gas turbine combustion needs to be within a certain range, otherwise the operation of the gas turbine will be unstable. The gasifier load determines the amount of syngas produced, and the gas production determines the syngas pressure before the gas turbine. The syngas pressure before the gas turbine determines the safe operation boundary of the gas turbine and the working capacity of the gas turbine. Therefore, when estimating the corresponding relationship between the gasifier load and the gas turbine load, the influence of the syngas calorific value and syngas pressure should also be comprehensively considered. They are closely related and affect each other.

[0036] Obtaining gasifier parameters of the IGCC unit, and determining the gasifier load change rate according to the gasifier parameters;

[0037] The gasifier load change rate is determined according to the gasifier load change rate; the gasifier load change rate determines the gas production speed of the gasifier, and the produced gas is supplied to the gas turbine for use. Therefore, the gasifier load change rate determines the gas turbine load change rate, and the amount of gas turbine load determines the amount of unit load. Therefore, the gas turbine load change rate directly affects the unit load change rate. By increasing the gas turbine load change rate, the unit load change rate can be increased.

[0038] Obtain the pre-machine synthesis gas pressure boundary conditions; the boundary conditions are the upper and lower limits of the synthesis gas pressure that can ensure the safe operation of the gas turbine. When the synthesis gas pressure is lower than the lower limit, or the synthesis gas pressure is higher than the upper limit, it will endanger the safe operation of the gas turbine and is not conducive to the stable operation of the unit. Through the safety boundary conditions, determine the upper and lower limits of the synthesis gas pressure for the subsequent second power and third power regulators.

[0039] According to the linear relationship between the gas turbine load and the gasifier load, the gasifier load change rate, the gas turbine load change rate and the pre-syngas pressure boundary conditions, the gas turbine load and the gasifier load are adjusted to complete the adjustment of the IGCC unit load. Load refers to the active power. The unit load represents the active power of the unit, that is, the unit's power generation capacity. The unit load is composed of the gas turbine load and the steam turbine load. When the unit load needs to be adjusted, it is mainly achieved by adjusting the gas turbine load. The steam turbine load will rise and fall with the gas turbine load, but the steam turbine load adjustment means are limited. Therefore, when the unit load is adjusted, it is mainly achieved by adjusting the gas turbine load. The purpose of this patent is to increase the rate of change of the unit load, that is, the speed of adjusting the unit load. Therefore, increasing the rate of change of the gas turbine load can increase the rate of change of the unit load.

[0040] The gas turbine load change rate is determined according to the gasifier load change rate, so that the gas turbine load change matches the gasifier load change, which can ensure that the unit operates within the safety boundary.

[0041] In an embodiment of the present invention, the method for obtaining the pre-syngas pressure boundary condition is specifically as follows:

[0042] According to the change of the syngas pressure before the engine and the engine operating conditions, the upper and lower limits of the syngas pressure are determined, which will be used as the set values ​​SP of the second power regulator and the third power regulator described later.

[0043] In the embodiment of the present invention, adjusting the gas turbine load and the gasifier load to adjust the IGCC unit load includes the following sub-steps:

[0044] Determine the actual load instruction of the unit according to the AGC instruction of the network, the upper limit value of the unit load, the lower limit value of the unit load and the unit load change rate;

[0045] Determining a first power output value according to the actual power generated by the gas turbine, the actual power generated by the steam turbine and the actual load instruction of the unit;

[0046] Determining a second power output value according to the syngas pressure value before the machine and the syngas pressure lower limit value;

[0047] taking the minimum value of the first power output value and the second power output value as the third power output value;

[0048] Determining a fourth power output value according to a syngas pressure value before the machine and an upper limit value of the syngas pressure;

[0049] taking the maximum value of the third power output value and the fourth power output value as the fifth power output value;

[0050] The engine load output value is determined according to the fifth power output value and the engine load change rate setting value; the engine load output value is obtained after the fifth power output value is changed, and the engine load output value is the engine load instruction. The change of the engine load instruction determines the engine load change speed and change amount.

[0051] Determine the gasifier outlet pressure setting value according to the pre-machine synthesis gas pressure value and the pre-machine pressure setting value;

[0052] The gasifier load output value is determined according to the gasifier outlet pressure value, the gasifier outlet pressure setting value, the gas turbine actual power and the gasifier load change rate setting value.

[0053] In an embodiment of the present invention, a method for determining the actual load instruction of a unit is specifically as follows: a network AGC instruction, a unit load upper limit value, and a unit load lower limit value are used as a unit load instruction without rate limitation after high and low value judgment, and the actual load instruction of the unit is generated according to the unit load instruction without rate limitation and the unit load variable rate setting value.

[0054] In an embodiment of the present invention, a method for determining the first power output value is specifically as follows: taking the actual power of the gas turbine as the measured value PV of the first power regulator, and inputting it into the first power regulator of the IGCC unit; taking the value after performing a difference operation between the actual load instruction of the unit and the actual power of the steam turbine as the set value SP of the first power regulator, and inputting it into the first power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measured value PV and the set value SP through the first power regulator of the IGCC unit to generate a first power output value.

[0055] 6. According to claim 3, the coordinated control method for improving the load change rate of the IGCC unit is characterized in that: the method for determining the second power output value is specifically: the pre-machine synthesis gas pressure value is used as the measurement value PV of the second power regulator, and is input into the second power regulator of the IGCC unit; the synthesis gas pressure lower limit value is used as the set value SP of the second power regulator, and is input into the second power regulator of the IGCC unit; the second power regulator of the IGCC unit performs proportional operation, integral operation and differential control operation on the input measurement value PV and the set value SP to generate the second power output value.

[0056] In an embodiment of the present invention, a method for determining the fourth power output value is specifically as follows: taking the pre-machine synthesis gas pressure value as the measurement value PV of the third power regulator, and inputting it into the third power regulator of the IGCC unit; taking the synthesis gas pressure upper limit value as the set value SP of the third power regulator, and inputting it into the third power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measurement value PV and the set value SP through the third power regulator of the IGCC unit to generate the fourth power output value.

[0057] In an embodiment of the present invention, a method for determining a set value of the gasifier outlet pressure is specifically as follows: using the pre-machine syngas pressure as the fourth power regulator; a method for determining a set value of the pre-machine syngas pressure is specifically as follows: using the pre-machine syngas pressure value as the measured value PV of the fourth power regulator, and inputting it into the fourth power regulator of the IGCC unit; using the pre-machine set rate as the set value SP of the fourth power regulator, and inputting it into the fourth power regulator of the IGCC unit; performing proportional operation, integral operation and differential control operation on the input measured value PV and the set value SP in the fourth power regulator of the IGCC unit, to generate a set value of the pre-machine syngas pressure.

[0058] In an embodiment of the present invention, a method for determining a gasifier load output value is specifically as follows: the gasifier outlet pressure value is used as the measured value PV of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; the pre-syngas pressure constant is used as the set value SP of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; the actual power generated by the gas turbine is used as the feedforward value FF of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; and proportional operation, integral operation and differential control operation are performed on the input measured value PV, set value SP and feedforward value FF in the fifth power regulator of the IGCC unit to generate a gasifier load output value.

[0059] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A coordinated control method for improving the load change rate of an IGCC unit, characterized in that: The following steps are involved: Obtaining the operating data of the IGCC unit, and determining the linear relationship between the gas turbine load and the gasifier load based on the operating data; wherein the operating data includes the gasifier load, the actual power of the gas turbine, the actual power of the steam turbine, the calorific value of the synthesis gas, the pressure value of the synthesis gas before the unit, the lower limit value of the synthesis gas pressure, and the upper limit value of the synthesis gas pressure; Obtaining gasifier parameters of the IGCC unit, and determining the gasifier load change rate according to the gasifier parameters; Determine the gas turbine load change rate according to the gasifier load change rate; Obtain the pre-machine synthesis gas pressure boundary conditions; According to the linear relationship between the gas turbine load and the gasifier load, the gasifier load change rate, the gas turbine load change rate and the pre-syngas pressure boundary conditions, the gas turbine load and the gasifier load are adjusted to complete the adjustment of the IGCC unit load.

2. The coordinated control method for improving the load change rate of an IGCC unit according to claim 1, characterized in that: The method for obtaining the pre-syngas pressure boundary condition is specifically as follows: The upper and lower limits of the synthesis gas pressure are determined based on the change in the synthesis gas pressure before the gas turbine and the operating conditions of the gas turbine.

3. The coordinated control method for improving the load change rate of an IGCC unit according to claim 1, characterized in that: The step of adjusting the gas turbine load and the gasifier load to adjust the IGCC unit load includes the following sub-steps: Determine the actual load instruction of the unit according to the AGC instruction of the network, the upper limit value of the unit load, the lower limit value of the unit load and the unit load change rate; Determining a first power output value according to the actual power generated by the gas turbine, the actual power generated by the steam turbine and the actual load instruction of the unit; Determining a second power output value according to the syngas pressure value before the machine and the syngas pressure lower limit value; taking the minimum value of the first power output value and the second power output value as the third power output value; Determining a fourth power output value according to a syngas pressure value before the machine and an upper limit value of the syngas pressure; taking the maximum value of the third power output value and the fourth power output value as the fifth power output value; Determining the engine load output value according to the fifth power output value and the engine load variable rate setting value; Determine the gasifier outlet pressure setting value according to the pre-machine synthesis gas pressure value and the pre-machine pressure setting value; The gasifier load output value is determined according to the gasifier outlet pressure value, the gasifier outlet pressure setting value, the gas turbine actual power and the gasifier load change rate setting value.

4. The coordinated control method for improving the load change rate of an IGCC unit according to claim 3, characterized in that: The method for determining the actual load instruction of the unit is specifically as follows: the network AGC instruction, the unit load upper limit value and the unit load lower limit value are used as the unit load instruction without rate limit after high and low value judgment, and the unit actual load instruction is generated according to the unit load instruction without rate limit and the unit load variable rate setting value.

5. The coordinated control method for improving the load change rate of an IGCC unit according to claim 3, characterized in that: The method for determining the first power output value is specifically as follows: taking the actual power of the gas turbine as the measured value PV of the first power regulator, and inputting it into the first power regulator of the IGCC unit; taking the value after performing a difference operation between the actual load instruction of the unit and the actual power of the steam turbine as the set value SP of the first power regulator, and inputting it into the first power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measured value PV and the set value SP by the first power regulator of the IGCC unit to generate the first power output value.

6. The coordinated control method for improving the load change rate of an IGCC unit according to claim 3, characterized in that: The method for determining the second power output value is specifically as follows: taking the pre-machine synthesis gas pressure value as the measurement value PV of the second power regulator, and inputting it into the second power regulator of the IGCC unit; taking the synthesis gas pressure lower limit value as the set value SP of the second power regulator, and inputting it into the second power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measurement value PV and the set value SP by the second power regulator of the IGCC unit to generate the second power output value.

7. The coordinated control method for improving the load change rate of an IGCC unit according to claim 3, characterized in that: The method for determining the fourth power output value is specifically as follows: taking the pre-machine synthesis gas pressure value as the measurement value PV of the third power regulator, and inputting it into the third power regulator of the IGCC unit; taking the synthesis gas pressure upper limit value as the set value SP of the third power regulator, and inputting it into the third power regulator of the IGCC unit; and performing proportional operation, integral operation and differential control operation on the input measurement value PV and the set value SP through the third power regulator of the IGCC unit to generate the fourth power output value.

8. The coordinated control method for improving the load change rate of an IGCC unit according to claim 3, characterized in that: The method for determining the set value of the gasifier outlet pressure is specifically as follows: using the pre-machine syngas pressure as the measured value PV of the fourth power regulator, and inputting it into the fourth power regulator of the IGCC unit; using the pre-machine set rate as the set value SP of the fourth power regulator, and inputting it into the fourth power regulator of the IGCC unit; performing proportional operation, integral operation and differential control operation on the input measured value PV and set value SP in the fourth power regulator of the IGCC unit, to generate the pre-machine syngas pressure set value.

9. The coordinated control method for improving the load change rate of an IGCC unit according to claim 3, characterized in that: The method for determining the gasifier load output value is specifically as follows: the gasifier outlet pressure value is used as the measured value PV of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; the pre-syngas pressure constant is used as the set value SP of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; the actual power generated by the gas turbine is used as the feedforward value FF of the fifth power regulator, and is input into the fifth power regulator of the IGCC unit; and the gasifier load output value is generated by performing proportional operation, integral operation and differential control operation on the input measured value PV, set value SP and feedforward value FF in the fifth power regulator of the IGCC unit.

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