CN-121977201-A - Fly ash high-temperature internal circulation stable combustion system and method integrating climbing optimization

CN121977201ACN 121977201 ACN121977201 ACN 121977201ACN-121977201-A

Abstract

The application discloses an integrated climbing optimization fly ash high-temperature internal circulation stable combustion system and method, wherein a fly ash extraction module is arranged at a vertical section of a flue between a boiler economizer and an air preheater and is used for extracting high-temperature fly ash, a fly ash conveying module is connected with the fly ash extraction module and is used for carrying out gas-solid separation, buffering and conveying the extracted fly ash in a dense phase flow state, a fly ash injection module is circumferentially arranged around a furnace wall of a main burner area of a boiler, an intelligent control system comprises a basic control layer and a combustion enhancement feedforward control module, the basic control layer is used for adjusting fly ash reinjection flow according to a boiler load instruction and a real-time combustion signal to match a current load, the combustion enhancement feedforward control module is used for controlling the fly ash reinjection to be lifted to a peak flow and carrying out preheating saturation treatment on a combustion area, and the climbing rate of a unit is improved through the double functions of preheating saturation and heat pulse.

Inventors

DAI ZHENGGANG
LIU JIALI
LIU JIAHUA
LIU JIE
LI SHUHUI
DAI SHIYAO
LI BO
LI PEIYU

Assignees

山西碳联新能源科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260127

Claims (10)

1. The integrated climbing optimization fly ash high-temperature internal circulation stable combustion system is characterized by comprising a fly ash extraction module, a fly ash conveying module, a fly ash injection module and an intelligent control system; The fly ash extraction module is arranged at the vertical section of the flue between the boiler economizer and the air preheater and is used for extracting high-temperature fly ash; the fly ash conveying module is connected with the fly ash extracting module and is used for carrying out gas-solid separation, buffering and conveying the extracted fly ash in a dense phase flow state; the fly ash spraying modules are circumferentially arranged around a furnace wall of the main burner area of the boiler and are used for uniformly spraying fly ash into the hearth to form a fly ash curtain covering the burner area; the intelligent control system is respectively in communication connection with the fly ash extraction module, the conveying and storage module and the injection module and comprises a basic control layer and a combustion strengthening feedforward control module; The basic control layer is used for adjusting fly ash reinjection flow according to a boiler load instruction and a real-time combustion signal so as to match the current load; The combustion strengthening feedforward control module is used for communicating with an automatic power generation control (AGC) system or a load prediction system of a power grid, controlling fly ash reinjection quantity to be lifted to peak flow after 60-90 seconds before a boiler load lifting and coal feeding instruction is executed, and carrying out preheating saturation treatment on a combustion area.
2. The integrated climbing optimization fly ash high-temperature internal circulation stable combustion system according to claim 1, wherein the fly ash conveying module comprises a cyclone separator, a fly ash buffer bin, a rotary feeding valve and a dense phase conveying pump, wherein the cyclone separator is used for separating out more than or equal to 95% of fly ash and falling into the fly ash buffer bin, the fly ash buffer bin is provided with a fluidization device for preventing the fly ash from hardening and maintaining stable material level, the rotary feeding valve quantitatively feeds the fly ash into the dense phase conveying pump, and the dense phase conveying pump uses compressed air as power to convey the fly ash to a hearth with a solid-gas ratio of 20-40 kg ash/kg gas.
3. The integrated hill climbing optimized fly ash high temperature internal circulation combustion stabilizing system of claim 1, wherein the fly ash extraction module comprises a negative pressure extractor, the negative pressure extractor is connected to a cyclone separator, the bottom outlet of the cyclone separator is connected to a fly ash buffer bin, the negative pressure extractor generates negative pressure through a high pressure fan, the fly ash in the flue is mixed with a small amount of flue gas, and the flue gas is extracted, and is connected to the cyclone separator to realize gas-solid primary separation.
4. The integrated hill climbing optimized fly ash high temperature internal circulation combustion stabilizing system of claim 3, wherein said negative pressure extractor comprises a venturi tube, a make-up air regulating valve and a wear resistant ceramic liner, the end of said negative pressure extractor is provided with an extraction port, said extraction port is provided with a grille filter.
5. The integrated hill climbing optimized fly ash high temperature internal circulation stable combustion system of claim 4, wherein said fly ash injection module comprises a plurality of adjustable wear resistant nozzles circumferentially arranged in the furnace burner area, said adjustable wear resistant nozzles internally provided with swirl vanes arranged under or laterally of the primary burner secondary air jets.
6. The integrated hill climbing optimized fly ash high temperature internal circulation combustion stabilizing system of claim 1, wherein said adjustable wear resistant nozzle is connected with an injection line, said injection line is equipped with a pneumatic quick closing valve and a flow regulating valve for precisely controlling the fly ash injection timing and flow.
7. The integrated hill climbing optimized fly ash high temperature internal circulation stable combustion system of claim 6, further comprising a fuel assist module comprising an atomized fuel spray gun, a high pressure oil/gas supply system, and a rapid executive valve, wherein the fuel assist module is configured to inject a trace amount of auxiliary fuel into the furnace to generate a heat pulse at an early stage of a rapid load-up process of the boiler.
8. The integrated hill climbing optimized fly ash high temperature internal circulation combustion stabilizing system of claim 1, wherein the intelligent control system is further provided with a fault alarm module, and when the fly ash extraction amount, the delivery pressure or the injection flow deviates from the set threshold value by + -10%, an alarm signal is immediately sent out and the control system is switched to a manual control mode.
9. The high-temperature internal circulation combustion stabilizing method for the fly ash with integrated climbing optimization is characterized by comprising the following steps of: s1, low-load stable combustion control, namely when the boiler load is in a 15% -20% rated load interval, adjusting fly ash reinjection amount through a basic control layer of an intelligent control system; S2, combustion strengthening feedforward preheating, namely when the trend of the power grid AGC load-increasing instruction is detected and the slope is larger than a set value, starting a combustion strengthening feedforward control module 60-90 seconds before the load-increasing coal feeding instruction is executed, lifting the fly ash reinjection amount to the peak flow, and preheating a combustion zone; S3, fast climbing cooperative reinforcement, namely analyzing a target climbing rate when a load-lifting coal feeding instruction is executed, and spraying a trace amount of auxiliary fuel if the target climbing rate is greater than or equal to a set threshold value to generate a heat pulse so as to accelerate load response; and S4, steady state recovery, namely gradually reducing the fly ash reinjection amount to a steady state value matched with the current load after the load climbing rate reaches a target value and the combustion of the hearth is stable, and stopping auxiliary fuel injection.
10. The integrated hill climbing optimization fly ash high temperature internal circulation stable combustion method of claim 9, wherein in step S4, after load climbing is stable, the rate of decrease of the fly ash reinjection amount is 0.5-1t/h.

Description

Fly ash high-temperature internal circulation stable combustion system and method integrating climbing optimization Technical Field The invention relates to the technical field of clean combustion of coal-fired boilers, in particular to a fly ash high-temperature internal circulation stable combustion system and method integrating climbing optimization. Background When the coal-fired boiler operates under low load, the temperature of the hearth is reduced, so that the coal powder is difficult to catch fire. In the prior art, the adoption of flue gas recirculation or hot air recirculation is a common means, but the problems of high power consumption of a fan, complex system and the like exist. Fly ash is a solid residue of pulverized coal combustion, the temperature is usually above 800 ℃, huge sensible heat is contained, but in the traditional technology, part of heat is wasted along with the exhaust of flue gas into a tail flue. How to safely and efficiently extract and return the high-temperature fly ash to a combustion zone of a hearth, and to preheat and stably burn by using the physical heat of the high-temperature fly ash is a technical problem. In addition, during rapid load rise, thermal inertia still exists solely by physical thermal preheating of fly ash, and a faster starting mechanism is needed to break through the initial inertia bottleneck. Disclosure of Invention The invention aims to provide a fly ash high-temperature internal circulation stable combustion system and method integrating climbing optimization to solve the problems in the background technology. In order to achieve the aim of the invention, the first technical scheme adopted by the invention is that the integrated climbing optimization fly ash high-temperature internal circulation stable combustion system comprises a fly ash extraction module, a fly ash conveying module, a fly ash injection module and an intelligent control system; The fly ash extraction module is arranged at the vertical section of the flue between the boiler economizer and the air preheater and is used for extracting high-temperature fly ash; the fly ash conveying module is connected with the fly ash extracting module and is used for carrying out gas-solid separation, buffering and conveying the extracted fly ash in a dense phase flow state; the fly ash spraying modules are circumferentially arranged around a furnace wall of the main burner area of the boiler and are used for uniformly spraying fly ash into the hearth to form a fly ash curtain covering the burner area; the intelligent control system is respectively in communication connection with the fly ash extraction module, the conveying and storage module and the injection module and comprises a basic control layer and a combustion strengthening feedforward control module; The basic control layer is used for adjusting fly ash reinjection flow according to a boiler load instruction and a real-time combustion signal so as to match the current load; The combustion strengthening feedforward control module is used for communicating with an automatic power generation control (AGC) system or a load prediction system of a power grid, controlling fly ash reinjection quantity to be lifted to peak flow after 60-90 seconds before a boiler load lifting and coal feeding instruction is executed, and carrying out preheating saturation treatment on a combustion area. The fly ash conveying module comprises a cyclone separator, a fly ash buffering bin, a rotary feeding valve and a dense-phase conveying pump, wherein the cyclone separator is used for separating out more than or equal to 95% of fly ash and falling into the fly ash buffering bin, the fly ash buffering bin is provided with a fluidization device for preventing the fly ash from hardening and maintaining stable material level, the rotary feeding valve quantitatively feeds the fly ash into the dense-phase conveying pump, and the dense-phase conveying pump uses compressed air as power to convey the fly ash to a hearth with a solid-gas ratio of 20-40 kg ash/kg gas. Further, the fly ash extraction module comprises a negative pressure extractor, the negative pressure extractor is connected to the cyclone separator, the bottom outlet of the cyclone separator is connected to the fly ash buffer bin, the negative pressure extractor generates negative pressure through a high-pressure fan, and the fly ash in the flue is mixed with a small amount of flue gas to be extracted and connected to the cyclone separator to realize gas-solid primary separation. Further, the negative pressure extractor comprises a venturi tube, an air supplementing regulating valve and a wear-resistant ceramic lining, wherein an extraction opening is formed in the end portion of the negative pressure extractor, and a grid filter is arranged in the extraction opening. Further, the fly ash injection module comprises a plurality of adjustable wear-resistant nozzles circumferentially arranged in the hearth