Blended coal blending combustion system for ultra-supercritical coal-fired power generation unit

Abstract

The utility model discloses a mixed coal blending combustion system for an ultra-supercritical coal-fired generator set, which comprises a raw coal bunker and a boiler, coal in the raw coal bunker is conveyed out by a coal feeder, the coal feeder conveys the coal to a coal grinding assembly, pulverized coal processed by the coal grinding assembly enters a pulverized coal bunker from a discharge port, the boiler is connected with a pulverized coal burner, a pulverized coal pipeline and an air bellow, and the air bellow is connected with the pulverized coal burner. The boiler is communicated with an electric dust remover through a pipeline, and the electric dust remover is communicated with follow-up equipment through a pipeline. Dynamic control over the air supply amount is achieved through the arranged air supply machine, the combustion rate of fuel is increased, and the better energy-saving effect is achieved; blended coal blending combustion is achieved through the coal feeder and the coal mill unit, meanwhile, the system is an ultra-supercritical coal-fired power generation unit, the utilization rate of fuel is increased, and energy saving of the system is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of coal-fired power generation, in particular to a coal blending combustion system for an ultra-supercritical coal-fired power generation unit. Background Technique

[0002] The critical parameters of water are: tc = 374.15 °C, Pc = 22.12 MPa. At the critical point and in the supercritical state, the evaporation phenomenon cannot be seen, and water directly changes from the liquid state to the gaseous state while remaining in a single phase. Generally, the range with a pressure greater than the critical point Pc is called the supercritical region, and the range with a pressure less than Pc is called the subcritical region. Ultra-supercritical is a concept applied in thermal power plants, indicating a higher stage of the development of supercritical technology, which is the natural development and extension of conventional steam-powered thermal power units. Ultra-supercritical units usually operate at pressures exceeding 25 MPa and temperatures of 600 °C. The ultra-supercritical technology enables water vapor to push the steam turbine at a higher energy state, thereby improving the power generation efficiency. The power supply efficiency of subcritical units is generally 36% - 38%, and the designed power supply coal consumption is about 340 - 320 g / (kW·h); the power supply efficiency of supercritical units is 41% - 43%, and the designed power supply coal consumption is about 300 - 286 g / (kW·h); by increasing the parameters and optimizing the system, the power supply efficiency can reach more than 46%, and the power supply coal consumption can be further reduced to less than 250 g / (kW·h). The energy-saving effect of ultra-supercritical thermal power generation units is remarkable. At the same time, due to the reduction of coal consumption, the emissions of dust, SO2, NOx, CO2, etc. are also greatly reduced.

[0003] The coal blending combustion system can optimize the combustion characteristics by mixing coals of different qualities or adding biomass fuels, reduce the use of high-sulfur and high-ash coals, and effectively reduce pollutant emissions. This technology enables power plants to flexibly adjust the fuel structure according to changes in the coal market, ensuring the maximization of economic and environmental benefits.

[0004] Defects such as the problems of high carbon emissions, environmental pollution, and resource consumption in traditional coal-fired power generation have become major obstacles to its development. In the global trend of pursuing low-carbon, environmentally friendly, and efficient energy utilization, the transformation and innovation of traditional coal-fired power generation are imperative. Content of the Utility Model

[0005] The purpose of the utility model is to provide a coal blending combustion system for an ultra-supercritical coal-fired power generation unit to solve the problems of excessive coal resource consumption and environmental pollution in traditional coal-fired power generation mentioned in the above background technique.

[0006] To achieve the above object, the utility model provides the following technical solutions: A coal blending combustion system for an ultra-supercritical coal-fired power generation unit, which includes a raw coal bunker, a boiler. The coal material in the raw coal bunker is transported out by a coal feeder. The coal feeder transports the coal material to a coal grinding assembly. The pulverized coal obtained by the treatment of the coal grinding assembly enters the pulverized coal bunker from the discharge port. Above the boiler, there are connected a pulverized coal bunker, a limestone powder bunker, a forced draft fan and a water sump. The boiler is connected to an electrostatic precipitator through a pipeline, and the electrostatic precipitator is connected to subsequent equipment through a pipeline.

[0007] Preferably, the raw coal bunker, the coal feeder, the coal grinding assembly, the pulverized coal bunker, the boiler, the limestone powder bunker, the forced draft fan and the water sump are all controlled by a controller.

[0008] Preferably, the raw coal bunker has multiple chambers and corresponding discharge ports.

[0009] Preferably, the coal grinding assembly is composed of multiple coal grinders and receives different kinds of coal materials transported by the coal feeder.

[0010] Preferably, sensors are installed on the raw coal bunker, the boiler and the boiler discharge pipeline.

[0011] Preferably, the system steam pressure ≥ 25 MPa and the steam temperature ≥ 600 °C.

[0012] Preferably, the boiler is equipped with an enriched type burner.

[0013] Compared with the prior art, the beneficial effects of the utility model are as follows: 1. The utility model realizes the dynamic control of the air supply volume through the set forced draft fan, increases the combustion rate of the fuel, and achieves better energy-saving effects.

[0014] 2. The utility model realizes coal blending combustion through the set coal feeder and coal grinding unit. At the same time, the system is an ultra-supercritical coal-fired power generation unit, which improves the utilization rate of the fuel and realizes the energy-saving of the system.

[0015] 3. The utility model realizes in-furnace desulfurization through the set limestone bin and electrostatic precipitator, reduces flue gas emissions, and further reduces emissions through the enriched type burner, thereby reducing environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the utility model.

[0017] In the figure: 1. Raw coal bunker; 2. Coal feeder; 3. Coal grinding assembly; 4. Pulverized coal bunker; 5. Boiler; 6. Limestone powder bunker; 7. Forced draft fan; 8. Electrostatic precipitator; 9. Water sump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0019] Please refer to Figure 1 , the present utility model provides a technical solution: a coal blending combustion system for an ultra-supercritical coal-fired power generation unit, including a raw coal bunker 1 and a boiler 5. Its characteristics are as follows: The coal material in the raw coal bunker 1 is transported out by a coal feeder 2. The coal feeder 2 transports the coal material to a coal grinding assembly 3. The pulverized coal obtained by the treatment of the coal grinding assembly 3 enters the pulverized coal bunker 4 from the discharge port. Above the boiler 5, there are connected a pulverized coal bunker 4, a limestone powder bunker 6, a forced draft fan 7, and a water tank 9. The pulverized coal in the pulverized coal bunker 4 enters the boiler 5 for combustion. The water tank 9 adds water to the boiler 5. In the boiler 5, there is a set of pipelines and heat exchangers. The combustion gas conducts heat to the water through the pipelines. Under high temperature and high pressure, the water will become in a supercritical state, that is, between liquid and gas states, with high density and thermal conductivity. The forced draft fan 7 is used to supply combustion air to the boiler 5, control the oxygen content in the furnace, and use the primary air supply to help the coal reach preheating. The secondary air supply is used to reduce the thermal gap in the furnace and control the air supply time to ensure that the combustion rate of the coal is in a reasonable state, which not only helps the stability of combustion but also can greatly reduce the heat loss. The boiler 5 is connected to an electrostatic precipitator 8 through pipelines. The electrostatic precipitator uses a high-voltage electric field to charge the dust and move it towards the electrode plates, effectively capturing fine particles, including sulfate particles generated by the desulfurization reaction, thereby effectively reducing pollutant emissions. The electrostatic precipitator 8 is connected to subsequent equipment through pipelines;

[0020] The raw coal bunker 1, the coal feeder 2, the coal grinding assembly 3, the pulverized coal bunker 4, the boiler 5, the limestone powder bunker 6, the forced draft fan 7, and the water tank 9 are all controlled by a controller;

[0021] The raw coal bunker 1 has multiple chambers and corresponding discharge ports; the controller controls the opening and closing of different discharge ports of the raw coal bunker 1 to control the coal output of the raw material, controls the opening and closing of the discharge port of the pulverized coal bunker 4 to control the combustion of the boiler, controls the opening and closing of the discharge port of the limestone powder bunker 6 to control the desulfurization reaction, controls the coal feeder 2 to transport the coal material, controls the operation of the coal grinding assembly 3 and the boiler 5, and controls the flow rates of the forced draft fan 7 and the water tank 9, so as to maintain the supercritical state and ensure the combustion efficiency.

[0022] The coal grinding assembly 3 is composed of multiple coal grinders, receiving different types of coal materials transported by the coal feeder 2. The multiple coal grinders can ensure that different types of coal materials adopt different coal grinding methods, so that they are all fully processed;

[0023] Sensors are installed on the raw coal bunker 1, the boiler 5, and the boiler discharge pipeline. The sensor on the raw coal bunker 1 monitors the coal quantity, the sensor on the boiler 5 monitors the combustion state of the boiler, and the discharge pipeline sensor is used to monitor pollutant emissions;

[0024] The steam pressure of the system is ≥25 MPa, and the steam temperature is ≥600 °C. The entire system is in an ultra-supercritical state;

[0025] The boiler 5 is equipped with an enriched burner. The enriched burner uses an enricher to achieve separation of thick and thin pulverized coal, stagnation concentration, and rapid temperature rise, enabling a small portion of the pulverized coal to ignite first to form small flames, and then using these small flames to ignite the entire primary air pulverized coal, thereby achieving stable combustion.

[0026] Working principle:

[0027] Mixing coal: The coal material enters the raw coal bunker 1 for separate storage. The sensor on the raw coal bunker 1 monitors the coal quantity. The system analyzes the mixing coal plan based on the currently stored coal quantity. The controller controls the opening of different discharge ports of the raw coal bunker 1 according to the mixing coal plan, and at the same time controls the feeder 2 to start. The feeder 2 transports different coal materials to different coal mills of different coal grinding components 3. The controller controls multiple coal mills to operate according to the coal grinding plan preset by the system. The controller controls the opening of the feed port of the pulverized coal bunker 4, and the ground coal material enters the pulverized coal bunker 4 for storage.

[0028] Co-firing: The controller controls the opening of the discharge port of the pulverized coal bunker 4, and at the same time controls the boiler 5 to start. The enriched burner in the boiler 5 achieves separation of thick and thin pulverized coal, stagnation concentration, and rapid temperature rise, enabling a small portion of the pulverized coal to ignite first to form small flames, and then using these small flames to ignite the entire primary air pulverized coal. The sensor on the boiler 5 monitors the change in the air supply volume. The controller controls the air content provided by the air supply fan 7 to achieve air distribution control of the boiler 5. The controller controls the water supply volume of the water bunker 9 to achieve steam temperature and distribution control, ensuring full combustion of the pulverized coal. During the combustion process, the controller controls the feeding volume of the limestone powder bunker 6. The limestone powder is pneumatically injected into the furnace, and the limestone powder decomposes into CaO and CO2. When the flue gas enters, part of the CaO reacts with part of the SO2 in the flue gas to produce CaSO4, thereby achieving desulfurization reaction and reducing pollution. After the flue gas flows out, the electrostatic precipitator 8 removes the particles in the flue gas and discharges them into the subsequent system.

[0029] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A coal blending combustion system for an ultra-supercritical coal-fired power generation unit, comprising a raw coal bunker (1) and a boiler (5), characterized in that: The coal material in the raw coal bunker (1) is transported out by the coal feeder (2). The coal feeder (2) transports the coal material to the coal grinding assembly (3). The pulverized coal obtained by processing the coal grinding assembly (3) enters the pulverized coal bunker (4) from the discharge port. Above the boiler (5), there are connected a pulverized coal bunker (4), a limestone powder bunker (6), a forced draft fan (7) and a water bunker (9). The boiler (5) is connected to an electrostatic precipitator (8) through a pipeline. The electrostatic precipitator (8) is connected to subsequent equipment through a pipeline.

2. The co - firing system for an ultra - supercritical coal - fired power generation unit according to claim 1, characterized in that: The raw coal bunker (1), the coal feeder (2), the coal grinding assembly (3), the pulverized coal bunker (4), the boiler (5), the limestone powder bunker (6), the forced draft fan (7) and the water bunker (9) are all controlled by a controller.

3. The co-firing system for an ultra-supercritical coal-fired power generation unit according to claim 1, characterized in that: The raw coal bunker (1) has multiple chambers and corresponding discharge ports.

4. A coal blending combustion system for an ultra-supercritical coal-fired power generation unit according to claim 1, characterized in that: The coal grinding assembly (3) is composed of multiple coal grinders and receives different types of coal materials transported by the coal feeder (2).

5. A co - firing system for an ultra - supercritical coal - fired power generation unit according to claim 1, characterized in that: Sensors are installed on the raw coal bunker (1), the boiler (5) and the boiler discharge pipeline.

6. The co - firing system for an ultra - supercritical coal - fired power generation unit according to claim 1, wherein: The system steam pressure ≥ 25 MPa and the steam temperature ≥ 600 °C.

7. A coal blending combustion system for an ultra-supercritical coal-fired power generation unit according to claim 1, characterized in that: The boiler (5) is equipped with an enriched burner.

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