A coal-fired unit rapid peak shaving method and system based on gas buffer compensation

Abstract

The present application belongs to the technical field of thermal power generation, and relates to a coal-fired unit rapid peak regulation method and system based on buffer compensation, comprising: obtaining a target load change amount according to a power grid target load and a current unit load; obtaining a coal side adjustable load amount based on a current allowed climbing rate of the coal side and a preset predetermined response time; obtaining a gas target flow according to the target load change amount and the coal side adjustable load amount; judging whether the power grid target load is greater than the current unit load and whether the coal side adjustable load amount is less than the target load change amount, and if so, performing an up-regulation load peak regulation based on the gas target flow and the coal side adjustable load amount; and if not, performing a down-regulation load peak regulation according to the coal side adjustable load amount. The present application performs coal side slow regulation and gas side fast compensation regulation through the coal side adjustable load amount and the gas side fast compensation amount, thereby solving the problems of slow response speed, poor flexibility, high investment cost and poor adaptability of existing coal-fired unit peak regulation.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, and specifically discloses a rapid peak-shaving method and system for coal-fired power units based on gas buffer compensation. Background Technology

[0002] Under the pressure of carbon emission reduction and the integration of a high proportion of new energy sources, coal-fired power plants need to simultaneously achieve carbon reduction and emission reduction while undertaking frequent peak-shaving tasks. Coupling biomass power generation with coal-fired units is an important technological path for the decarbonization of coal-fired power, mainly including direct coupling and gasification coupling. Direct coupling is achieved through the co-combustion of biomass and pulverized coal, and the system modification is simple. However, solid biomass has low energy density and significant combustion regulation lag, which cannot support the unit's rapid peak-shaving needs. Biomass gasification coupling first converts biomass into gas before sending it to the boiler for combustion. Compared with solid co-combustion, biomass gas has the potential to serve as a rapid heat input regulation medium for boilers. However, existing gasification coupling systems generally use gas as a conventional alternative fuel, and its rapid power regulation value has not yet been fully realized.

[0003] Currently, the existing solutions are as follows: The first solution collects parameters of fuel, boiler, and flue gas, and uses an optimization model to determine the optimal ratio of pulverized coal and natural gas to improve peak-shaving performance. However, the core focus is only on fuel ratio optimization, and no control mechanism is built to compensate for the lag in coal-side ramping by a gas buffer and pressure stabilization unit, resulting in a slow peak-shaving response. The second solution is a peak-shaving scheme that couples molten salt energy storage with gasification. Although the peak-shaving capacity is improved, a complete set of storage and heat exchange equipment is required, making the system complex and unsuitable for all in-service unit retrofit scenarios, resulting in high investment costs and poor adaptability. The third solution, the gas storage-type peak-shaving scheme, focuses on solving the problems of gas storage cooling and safe supply. It does not combine the actual ramping capacity of the coal side to dynamically calculate the rapid compensation amount of gas, nor does it achieve coordinated control of the gas storage tank pressure range and the unit's peak-shaving capacity, resulting in a slow peak-shaving response and poor flexibility. Summary of the Invention

[0004] The technical problem to be solved by this invention is that existing coal-fired power units have slow response speed, poor flexibility, high investment cost, and poor adaptability in peak shaving.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A rapid peak-shaving method for coal-fired power units based on buffer compensation includes: Collect operational data from coal-fired power units, including grid target load, current unit load, and current allowable ramp rate on the coal side. The change in target load is obtained based on the target load of the power grid and the current load of the generating units; Based on the current allowable ramp rate on the coal side and the preset response time, the adjustable load on the coal side is obtained; When the target load change is greater than the adjustable load on the coal side, the target gas flow rate is obtained based on the target load change and the adjustable load on the coal side. Determine whether the target load of the power grid is greater than the current load of the generating unit and whether the adjustable load on the coal side is less than the change in the target load. If so, increase the load for peak shaving based on the target gas flow and the adjustable load on the coal side; otherwise, decrease the load for peak shaving based on the adjustable load on the coal side.

[0006] The beneficial effects of this invention are as follows: By decomposing the target load change into adjustable load on the coal side and rapid compensation on the gas side (target gas flow rate), the coal side adjusts according to the adjustable load at a safe allowable rate (current allowable rate of rate decrease and rate of rate increase on the coal side). Simultaneously, the biomass gasification gas buffer and pressure stabilization unit and the gas rapid adjustment valve group provide rapid compensation on the gas side for the delayed response of the coal side. This shortens the response time of coal-fired units to the target load of the power grid, improving the response speed, peak-shaving flexibility, and adaptability of coal-fired units, while reducing investment costs. Replacing part of the pulverized coal combustion with biomass gas reduces fossil coal consumption and carbon emission intensity per unit of power generation. Utilizing biomass gas to handle some heat input changes during peak-shaving improves the low-carbon and flexible operation capability of coal-fired units.

[0007] Furthermore, when the target load change is greater than the adjustable load on the coal side, the target gas flow rate is obtained based on the target load change and the adjustable load on the coal side, including: The operating data also includes the amount of gas that can be released from the gas buffer tank, the boiler's safety allowable compensation, the biomass gas utilization rate, and the lower heating value of the biomass gas; Calculate the theoretical rapid compensation amount on the gas side based on the target load change and the adjustable load on the coal side; The release capacity of the gas buffer tank is calculated based on the biomass gas utilization rate, the lower heating value of biomass gas, the amount of gas that can be released from the gas buffer tank, and the preset peak-shaving response time. The rapid compensation amount on the gas side is obtained based on the theoretical rapid compensation amount on the gas side, the release capacity of the gas buffer tank, and the safe allowable compensation amount of the boiler. The target gas flow rate is obtained based on the rapid compensation amount on the gas side, the biomass gas utilization rate, and the lower heating value of biomass gas.

[0008] Furthermore, the formula for calculating the release capacity of the gas buffer tank is as follows: , in, For the gas buffer tank's release capacity, To improve the utilization rate of biomass gas, The lower heating value of biomass gas, The gas buffer tank can release a certain amount of gas. This refers to the peak-shaving response time.

[0009] Furthermore, the formula for calculating the rapid compensation amount on the gas side is: , in, This is the rapid compensation amount on the gas side. This is the theoretical rapid compensation amount on the gas side. For the gas buffer tank's release capacity, This is the allowable compensation amount for boiler safety.

[0010] Furthermore, the formula for calculating the target gas flow rate is: , in, For the target flow rate of gas, This is the rapid compensation amount on the gas side. To improve the utilization rate of biomass gas, It is the lower heating value of biomass gas.

[0011] Furthermore, load shaving and peak regulation are carried out based on the target gas flow rate and the adjustable load on the coal side, including: When the gas-fired boiler co-control module is in control, the gas rapid regulating valve group opens, allowing the biomass gas in the gas buffer and pressure stabilizing unit to enter the furnace of the coal-fired boiler for combustion according to the target gas flow rate. Meanwhile, the coal-side load regulation unit increases the coal feed rate and air distribution rate at a uniform rate according to the current allowable ramp rate of the coal side, based on the adjustable load on the coal side. Ultimately, this allows the unit's current load to reach the grid's target load.

[0012] Furthermore, load reduction and peak shaving are implemented based on the adjustable load on the coal side, including: The boiler-gas co-control unit prioritizes reducing the opening of the gas rapid regulating valve group to reduce the flow of biomass gas entering the coal-fired boiler; At the same time, the coal-side load regulating unit reduces the coal feed rate and air distribution rate uniformly according to the adjustable load on the coal side and the current allowable slope reduction rate on the coal side. Ultimately, this allows the unit's current load to reach the grid's target load.

[0013] Furthermore, during peak shaving, follow-up gas supply to the biomass gasifier is implemented, including: As biomass gas is released, the pressure in the gas buffer tank gradually decreases. When the pressure in the gas buffer tank is lower than the lower limit of the peak-shaving standby range, the biomass feed rate and gasifying agent flow rate are increased to increase the gas production of the biomass gasifier. When the pressure of the gas buffer tank returns to the peak-shaving standby range, the biomass gasifier maintains stable gas production. When the pressure in the gas buffer tank exceeds the upper limit of the peak-shaving standby range, reduce the biomass feed rate and gasification agent flow rate, or perform safe disposal through the bypass safe disposal module.

[0014] The beneficial effects of this invention are: by not requiring the biomass gasifier to directly and quickly follow the changes in the target load of the power grid, but instead having the gas buffer tank undertake short-term rapid compensation, and the gasifier smoothly tracking and replenishing gas according to the pressure changes in the buffer tank, it is beneficial to reduce the risks of bed temperature fluctuations, biomass gas calorific value fluctuations, tar increase, and slagging in the biomass gasifier.

[0015] Furthermore, during peak shaving, the biomass fuel gas entering the coal-fired boiler will be restricted or cut off if any of the following situations occur: The following are considered as separate issues: the pressure in the gas buffer tank is below the safety lower limit; the oxygen content of the biomass gas is above the first oxygen content threshold; the lower heating value of the biomass gas is below the stable combustion threshold; the temperature or pressure of the biomass gas exceeds the gas safety threshold; the negative pressure in the furnace exceeds the safe negative pressure range; the oxygen content in the furnace is below the second oxygen content threshold; the CO concentration exceeds the concentration threshold; and the flame detector signal disappears.

[0016] The beneficial effects of this invention are: by monitoring the pressure of the gas buffer tank, the oxygen content of biomass gas, the calorific value of biomass gas, the temperature of biomass gas, the pressure of biomass gas, the negative pressure of the furnace, the oxygen content of the furnace, the CO concentration, the flame detection signal, etc., safety constraints can be implemented, which can reduce the adverse effects of rapid injection of biomass gas on the stable combustion of coal-fired boilers.

[0017] This invention also relates to a rapid peak-shaving system for coal-fired power units based on buffer compensation, used in the aforementioned rapid peak-shaving method for coal-fired power units based on buffer compensation, comprising: Biomass gasification module, gas purification and cooling module, gas buffer and pressure stabilization module, gas detection module, gas fast regulating valve group, coal-fired boiler gas injection module, coal-side load regulation module, turbine-furnace-gas coordinated control module, power grid load command receiving module, bypass safety absorption module, safety limiting module, boiler safety monitoring module; The biomass gasification module is connected to the gas purification and cooling module. The gas buffer and pressure stabilization module is connected to the gas purification and cooling module, the gas fast regulating valve group, and the bypass safety absorption module. The coal-fired boiler gas injection module is connected to the gas fast regulating valve group and the coal-side load regulating module. The boiler-machine gas coordinated control module is electrically connected to the biomass gasification module, the power grid load command receiving module, the gas detection module, the coal-side load regulating module, the safety limiting module, and the boiler safety monitoring module. The safety limiting module is electrically connected to the gas fast regulating valve group and the boiler safety monitoring module.

[0018] The advantages of this invention are: the system structure is relatively simple and suitable for retrofitting existing coal-fired units; it does not require the introduction of molten salt thermal storage systems, independent biomass turbine power generation systems or complex parallel systems, but is achieved only through gas buffer and pressure stabilization units, gas fast regulating valve groups, gas detection units and boiler-turbine gas collaborative control units; the retrofit boundaries are clear, the engineering adaptability is strong, and the investment cost is low. Attached Figure Description

[0019] Figure 1 This is a flowchart of a rapid peak-shaving method for coal-fired power units based on gas buffer compensation, as described in an embodiment of the present invention. Figure 2 This is a block diagram of a rapid peak-shaving system for coal-fired power units based on gas buffer compensation, as described in an embodiment of the present invention. Detailed Implementation

[0020] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] A rapid peak-shaving method for coal-fired power units based on buffer compensation, such as Figure 1 As shown, it includes the following steps: S1. Collect operating data of coal-fired power units; Operating data includes the unit's current load, the grid's target load, the current allowable ramp rate on the coal side, biomass gas utilization rate, the lower heating value of biomass gas, the amount of gas that can be released from the gas buffer tank, the boiler's safety allowable compensation, main steam pressure, main steam temperature, furnace negative pressure, furnace oxygen content, CO concentration, coal feed rate, pulverizing rate, air distribution rate, biomass gas flow rate, biomass gas pressure, biomass gas temperature, biomass gas lower heating value, gas buffer tank pressure, biomass feed rate, gasifying agent flow rate, and gasifier bed temperature. Among these, the gas buffer tank pressure is used to determine whether the gas buffer pressure stabilization unit is currently at its lower safety limit, peak-shaving reserve range, or upper safety limit.

[0022] S2. Obtain the change in target load based on the target load of the power grid and the current load of the generating units; The formula for calculating the target load change is: , in, For the target load of the power grid, The current load of the unit, This represents the target load change.

[0023] when A value greater than zero indicates that the coal-fired unit needs to increase its load; when When the value is less than zero, it indicates that the coal-fired unit needs to reduce its load; when When the value is zero, it indicates that the coal-fired unit is maintaining its current load.

[0024] S3. Based on the current allowable ramp rate on the coal side and the preset response time, obtain the adjustable load on the coal side; The formula for calculating the adjustable load on the coal side is: , in, For adjustable load on the coal side, This represents the current permissible ramp rate on the coal side. This is the scheduled response time.

[0025] The current allowable ramp rate on the coal side can be dynamically adjusted below the maximum allowable ramp rate for coal-fired power units.

[0026] S4. When the target load change is greater than the adjustable load on the coal side, the target gas flow rate is obtained based on the target load change and the adjustable load on the coal side. S41. Calculate the theoretical rapid compensation amount on the gas side based on the target load change and the adjustable load on the coal side; The formula for calculating the theoretical rapid compensation amount on the gas side is: - , in, This is the theoretical rapid compensation amount on the gas side. For the target load change, The load can be adjusted on the coal side.

[0027] S42. Calculate the release capacity of the gas buffer tank based on the biomass gas utilization rate, the lower heating value of biomass gas, the amount of gas that can be released from the gas buffer tank, and the preset peak-shaving response time. The formula for calculating the release capacity of a gas buffer tank is: , in, This refers to the releasable capacity of the gas buffer tank; Biomass gas utilization rate, i.e., the effective utilization rate of biomass gas heat input by the boiler; The lower heating value of biomass gas; The amount of gas that the gas buffer tank can release is the amount of gas that the gas buffer tank can release within the safe pressure range. This refers to the peak-shaving response time.

[0028] The calorific value of biomass gas includes the lower heating value and the higher heating value. The lower heating value of biomass gas refers to the effective heat released after a specified amount of biomass gas is completely burned, after deducting the latent heat of condensation of water vapor generated during combustion. The higher heating value of biomass gas refers to the heat released after a specified amount of biomass gas is completely burned, including the latent heat of condensation of water vapor generated during combustion.

[0029] S43. Obtain the rapid compensation amount on the gas side based on the theoretical rapid compensation amount on the gas side, the release capacity of the gas buffer tank, and the safe allowable compensation amount of the boiler. The formula for calculating the rapid compensation amount on the gas side is: , in, This is the rapid compensation amount on the gas side. This is the theoretical rapid compensation amount on the gas side. This refers to the releasable capacity of the gas buffer tank; This refers to the boiler's permissible compensation amount for safety, i.e., the maximum amount of gas compensation allowed within the boiler's safety boundary.

[0030] The safety limiting module takes the minimum value among the theoretical rapid compensation amount on the gas side, the release capacity of the gas buffer tank, and the boiler's safe allowable compensation amount as the rapid compensation amount on the gas side, so that the rapid compensation amount on the gas side is limited to the allowable range of the boiler's safety boundary.

[0031] S44. Based on the rapid compensation amount on the gas side, the biomass gas utilization rate, and the lower heating value of biomass gas, the target gas flow rate is obtained. The formula for calculating the target flow rate of natural gas is: , in, For the target flow rate of gas, This is the rapid compensation amount on the gas side. To improve the utilization rate of biomass gas, It is the lower heating value of biomass gas.

[0032] When the lower heating value of biomass gas fluctuates, the boiler-gas co-control unit adjusts the target gas flow rate based on the real-time lower heating value of biomass gas to avoid deviations in the heat input of the coal-fired boiler caused by changes in the lower heating value of biomass gas.

[0033] S5. Determine whether the target load of the power grid is greater than the current load of the generating unit and whether the adjustable load on the coal side is less than the change in the target load. If so, increase the load for peak shaving based on the target gas flow and the adjustable load on the coal side; otherwise, decrease the load for peak shaving based on the adjustable load on the coal side.

[0034] Load shaving and peak regulation based on target gas flow and adjustable coal-side load includes: When the boiler-furnace-gas coordinated control module is activated, the gas rapid regulating valve group opens, allowing biomass gas from the gas buffer and pressure stabilizing unit to enter the furnace of the coal-fired boiler for combustion according to the target gas flow rate, compensating for the lag in coal-side response. Simultaneously, the coal-side load regulating unit gradually increases (usually at a constant rate) the coal feed and air distribution based on the adjustable coal-side load and the current allowable ramp-up rate (i.e., the allowable ramp-up rate of the coal-fired boiler). Ultimately, this ensures that the unit's current load reaches the grid target load. This achieves rapid heat input compensation on the gas side first; as the coal-side heat input gradually increases, the boiler-furnace-gas coordinated control unit gradually reduces the gas-side compensation, allowing the coal-fired unit to smoothly reach the grid target load.

[0035] Load reduction and peak shaving based on the adjustable load on the coal side includes: The boiler-gas co-control unit prioritizes reducing the opening of the rapid gas regulating valve group to decrease the flow of biomass gas into the coal-fired boiler, thereby rapidly reducing the boiler heat input. Simultaneously, the coal-side load regulating unit gradually reduces (usually at a uniform rate) the coal feed and air distribution according to the adjustable load on the coal side and the current allowable rate of rate reduction. Ultimately, this ensures the unit's current load reaches the grid target load, thus improving the unit's bidirectional regulation flexibility. During load reduction, if the biomass gasifier continues to output biomass gas and the gas buffer tank pressure has not reached the safety limit, the biomass gas is input into the gas buffer pressure stabilizing unit for storage. If the gas buffer tank pressure reaches or approaches the safety limit, the boiler-gas co-control unit reduces the biomass gasifier feed and gasifying agent flow, or activates the bypass safety absorption module to safely absorb excess biomass gas.

[0036] During peak shaving, follow-up gas supply to the biomass gasifier is implemented, including: As biomass gas is released, the pressure in the gas buffer tank gradually decreases. The boiler-gas co-control unit sends a follow-up gas supply command to the biomass gasification unit based on the pressure deviation of the gas buffer tank, the rate of pressure drop, and the peak-shaving reserve range. When the pressure in the gas buffer tank is lower than the lower limit of the peak-shaving reserve range, the biomass feed rate and gasifying agent flow rate are gradually increased to increase the gas production of the biomass gasifier. When the pressure in the gas buffer tank returns to the peak-shaving reserve range, the biomass gasifier maintains stable gas production. When the pressure in the gas buffer tank is higher than the upper limit of the peak-shaving reserve range, the biomass feed rate and gasifying agent flow rate are reduced, or the gas consumption on the boiler side is increased, or safe consumption is achieved through the bypass safety consumption module.

[0037] In addition, during peak shaving, the boiler-gas co-operation control unit performs safety control based on real-time monitoring parameters of the coal-fired boiler and biomass gas, which can reduce the adverse effects of rapid biomass gas injection on the stable combustion of the coal-fired boiler; when any of the following situations occur, the biomass gas entering the coal-fired boiler is restricted or cut off: The following are considered abnormal conditions: the pressure in the gas buffer tank is below the safety lower limit; the oxygen content of the biomass gas is above the first oxygen threshold; the lower heating value of the biomass gas is below the stable combustion threshold; the temperature or pressure of the biomass gas exceeds the gas safety threshold; the negative pressure in the furnace exceeds the safe negative pressure range, i.e., the furnace negative pressure is abnormal; the oxygen content in the furnace is below the second oxygen threshold; the CO concentration exceeds the concentration threshold; the flame detector signal disappears, i.e., the flame detector signal is abnormal.

[0038] The gas buffer tank pressure is divided into a lower safety limit and a higher safety limit, enabling more precise peak-shaving response. When the gas buffer tank pressure is within the peak-shaving standby range, it indicates that the gas side has peak-shaving capability (rapid release capability), but it still needs to be checked against the boiler safety boundary. Only when parameters such as furnace oxygen content, furnace negative pressure, CO concentration, flame detector signal, biomass gas pressure, and biomass gas temperature meet safety requirements are the gas rapid regulating valve group allowed to open within the limit of the rapid compensation amount on the gas side. When the boiler safety boundary does not allow for increased gas injection, the system restricts or cuts off biomass gas injection, and the coal side adjusts according to the safe allowable rate (the safe allowable rate includes the current allowable rate of decline and the current allowable rate of climb on the coal side).

[0039] This invention also relates to a rapid peak-shaving system for coal-fired power units based on buffer compensation, such as... Figure 2 As shown, it includes: The system includes a biomass gasification module, a gas purification and cooling module, a gas buffer and pressure stabilization module, a gas detection module, a gas rapid regulating valve group, a coal-fired boiler gas injection module, a coal-side load regulation module, a boiler-machine gas coordinated control module, a power grid load command receiving module, a bypass safety absorption module, a safety limiting module, and a boiler safety monitoring module. The biomass gasification module is connected to the gas purification and cooling module. The gas buffer and pressure stabilization module is connected to the gas purification and cooling module, the gas rapid regulating valve group, and the bypass safety absorption module, respectively. The coal-fired boiler gas injection module is connected to the gas rapid regulating valve group and the coal-side load regulation module, respectively. The boiler-machine gas coordinated control module is electrically connected to the biomass gasification module, the power grid load command receiving module, the gas detection module, the coal-side load regulation module, the safety limiting module, and the boiler safety monitoring module, respectively. The safety limiting module is electrically connected to the gas rapid regulating valve group and the boiler safety monitoring module, respectively.

[0040] The biomass gasification module includes a biomass silo, a feeding device, and a biomass gasifier. The biomass silo is used to store biomass raw materials such as straw and agricultural and forestry waste. The feeding device is used to meter and transport biomass raw materials. The biomass gasifier is used to gasify biomass raw materials to produce biomass gas, achieving stable gas production and follow-up gas replenishment.

[0041] The gas purification and cooling module is used to remove dust, cool down, and reduce the temperature of biomass gas.

[0042] The gas buffer and pressure stabilizing module is used to store biomass gas in a gas buffer tank and stabilize the pressure in the gas buffer tank.

[0043] The gas detection module is used to monitor in real time the pressure of the gas buffer tank, biomass gas flow rate, lower heating value of biomass gas, oxygen content of biomass gas, temperature of biomass gas, and pressure of biomass gas.

[0044] Gas quick-regulating valve assemblies are used to quickly open, regulate, or cut off the delivery of biomass gas.

[0045] The coal-fired boiler gas injection module is used to burn injected biomass gas to generate heat energy and heat water into steam; it includes a coal-fired boiler and a gas nozzle. The coal-fired boiler is used to burn biomass gas to generate heat energy and heat water into steam, and the gas nozzle is used to inject biomass gas into the coal-fired boiler.

[0046] The coal-side load regulation module is used to adjust the coal feed rate, coal grinding rate, and air distribution rate according to the adjustable load on the coal side at a safe and permissible rate.

[0047] The co-control module for boiler, turbine, and gas is used to calculate the adjustable load on the coal side and the target flow rate of the gas based on the collected operating data. Based on the adjustable load on the coal side and the target flow rate of the gas, it controls the gas fast regulating valve group to perform load increase or load decrease peak shaving.

[0048] The power grid load command receiving module is used to receive preset power grid target loads.

[0049] The bypass safety absorption module is used to eliminate excess biomass gas in the gas buffer tank.

[0050] The safety limiting module is used to limit the rapid compensation amount on the gas side within the allowable range of the boiler's safety boundary.

[0051] The boiler safety monitoring module is used to monitor furnace negative pressure, furnace oxygen content, CO concentration, flame detection signals, etc.

[0052] Biomass feedstock enters the biomass gasifier from the biomass silo via a feeding device. The biomass gasifier processes the generated biomass gas through a gas purification and cooling module before it enters a gas buffer and pressure stabilization module for storage and pressure stabilization. The gas buffer and pressure stabilization module is connected to the coal-fired boiler gas injection module via a gas rapid regulating valve group. The turbine-furnace-gas coordinated control module is electrically connected to the biomass gasification module, the power grid load command receiving module, the gas detection module, the coal-side load regulating module, the safety limiting module, and the boiler safety monitoring module. Based on the power grid target load, the current allowable ramp rate on the coal side, and the lower heating value of the biomass gas, the turbine-furnace-gas coordinated control module decomposes the target load change into the adjustable load on the coal side and the rapid compensation on the gas side.

[0053] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A rapid peak-shaving method for coal-fired power units based on buffer compensation, characterized in that, include: Collect operating data of coal-fired power units, including grid target load, current unit load, and current allowable ramp rate on the coal side; The change in target load is obtained based on the target load of the power grid and the current load of the generating units; Based on the current allowable ramp rate on the coal side and the preset response time, the adjustable load on the coal side is obtained; When the target load change is greater than the adjustable load on the coal side, the target gas flow rate is obtained based on the target load change and the adjustable load on the coal side. Determine whether the target load of the power grid is greater than the current load of the generating unit and whether the adjustable load on the coal side is less than the change in the target load. If so, increase the load for peak shaving based on the target gas flow and the adjustable load on the coal side; otherwise, decrease the load for peak shaving based on the adjustable load on the coal side.

2. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 1, characterized in that, When the target load change is greater than the adjustable load on the coal side, the target gas flow rate is obtained based on the target load change and the adjustable load on the coal side, including: The operational data also includes the amount of gas that can be released from the gas buffer tank, the boiler's safety allowable compensation, the biomass gas utilization rate, and the lower heating value of the biomass gas. Calculate the theoretical rapid compensation amount on the gas side based on the target load change and the adjustable load on the coal side; The release capacity of the gas buffer tank is calculated based on the biomass gas utilization rate, the lower heating value of biomass gas, the amount of gas that can be released from the gas buffer tank, and the preset peak-shaving response time. The rapid compensation amount on the gas side is obtained based on the theoretical rapid compensation amount on the gas side, the release capacity of the gas buffer tank, and the safe allowable compensation amount of the boiler. The target gas flow rate is obtained based on the rapid compensation amount on the gas side, the biomass gas utilization rate, and the lower heating value of biomass gas.

3. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 2, characterized in that, The formula for calculating the release capacity of a gas buffer tank is: ， in, For the gas buffer tank's release capacity, To improve the utilization rate of biomass gas, The lower heating value of biomass gas, The gas buffer tank can release a certain amount of gas. This refers to the peak-shaving response time.

4. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 2, characterized in that, The formula for calculating the rapid compensation amount on the gas side is: ， in, This is the rapid compensation amount on the gas side. This is the theoretical rapid compensation amount on the gas side. For the gas buffer tank's release capacity, This is the allowable compensation amount for boiler safety.

5. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 2, characterized in that, The formula for calculating the target flow rate of natural gas is: ， in, For the target flow rate of gas, This is the rapid compensation amount on the gas side. To improve the utilization rate of biomass gas, It is the lower heating value of biomass gas.

6. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 1, characterized in that, The load shaving and peak regulation based on target gas flow and adjustable coal-side load includes: When the gas-fired boiler co-control module is in control, the gas rapid regulating valve group opens, allowing the biomass gas in the gas buffer and pressure stabilizing unit to enter the furnace of the coal-fired boiler for combustion according to the target gas flow rate. Meanwhile, the coal-side load regulation unit increases the coal feed rate and air distribution rate at a uniform rate according to the current allowable ramp rate of the coal side, based on the adjustable load on the coal side. Ultimately, this allows the unit's current load to reach the grid's target load.

7. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 1, characterized in that, The method of reducing load and shaving peak load based on the adjustable load on the coal side includes: The boiler-gas co-control unit prioritizes reducing the opening of the gas rapid regulating valve group to reduce the flow of biomass gas entering the coal-fired boiler; At the same time, the coal-side load regulating unit reduces the coal feed rate and air distribution rate uniformly according to the adjustable load on the coal side and the current allowable slope reduction rate on the coal side. Ultimately, this allows the unit's current load to reach the grid's target load.

8. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 1, characterized in that, During peak shaving, follow-up gas supply to the biomass gasifier is implemented, including: As biomass gas is released, the pressure in the gas buffer tank gradually decreases. When the pressure in the gas buffer tank is lower than the lower limit of the peak-shaving standby range, the biomass feed rate and gasifying agent flow rate are increased to increase the gas production of the biomass gasifier. When the pressure of the gas buffer tank returns to the peak-shaving standby range, the biomass gasifier maintains stable gas production. When the pressure in the gas buffer tank exceeds the upper limit of the peak-shaving standby range, reduce the biomass feed rate and gasification agent flow rate, or perform safe disposal through the bypass safe disposal module.

9. The rapid peak-shaving method for coal-fired power units based on buffer compensation according to claim 1, characterized in that, During peak shaving, biomass fuel entering coal-fired boilers shall be restricted or cut off under any of the following circumstances: The following are considered as separate issues: the pressure in the gas buffer tank is below the safety lower limit; the oxygen content of the biomass gas is above the first oxygen content threshold; the lower heating value of the biomass gas is below the stable combustion threshold; the temperature or pressure of the biomass gas exceeds the gas safety threshold; the negative pressure in the furnace exceeds the safe negative pressure range; the oxygen content in the furnace is below the second oxygen content threshold; the CO concentration exceeds the concentration threshold; and the flame detector signal disappears.

10. A rapid peak-shaving system for coal-fired power units based on buffer compensation, characterized in that, A rapid peak-shaving method for coal-fired power units based on buffer compensation, as described in any one of claims 1-9, comprises: Biomass gasification module, gas purification and cooling module, gas buffer and pressure stabilization module, gas detection module, gas fast regulating valve group, coal-fired boiler gas injection module, coal-side load regulation module, turbine-furnace-gas coordinated control module, power grid load command receiving module, bypass safety absorption module, safety limiting module, boiler safety monitoring module; The biomass gasification module is connected to the gas purification and cooling module. The gas buffer and pressure stabilization module is connected to the gas purification and cooling module, the gas fast regulating valve group, and the bypass safety absorption module. The coal-fired boiler gas injection module is connected to the gas fast regulating valve group and the coal-side load regulating module. The boiler-machine gas coordinated control module is electrically connected to the biomass gasification module, the power grid load command receiving module, the gas detection module, the coal-side load regulating module, the safety limiting module, and the boiler safety monitoring module. The safety limiting module is electrically connected to the gas fast regulating valve group and the boiler safety monitoring module.

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