A system for burning distiller's grains in a pulverized coal boiler

Abstract

The present invention relates to the field of boiler fuel technology, and in particular to a system for blending distiller's grains with pulverized coal in a boiler, comprising: a coal conveyor, at least one coal bunker, a distiller's grains conveying device, at least one distiller's grains bunker, a first coal mill, a second coal mill, a distiller's grains blending controller, a first pulverizer, a second pulverizer, a blending air supply mechanism, and a furnace; the coal conveyor is connected to the coal bunker; the coal bunker is connected to the first pulverizer via the first coal mill, and the first pulverizer is connected to the furnace; the coal bunker is connected to the second coal mill; the distiller's grains conveying device is connected to the distiller's grains bunker; the distiller's grains bunker is connected to the second coal mill; and the second coal mill is connected to the furnace via the second pulverizer. The blending air supply mechanism is connected to the furnace; and the distiller's grains blending controller is electrically connected to the second coal mill. The pulverized coal blending distiller's grains system provided by the present invention can achieve precise blending of the fuel entering the furnace. The controller can realize online adjustment of the parameters of the distiller's grains bunker, the coal bunker, and the corresponding second coal mill pulverizing system, allowing for flexible adjustment.

Description

Technical Field

[0001] The invention relates to the technical field of boiler fuel, in particular to a pulverized coal boiler blended with distiller's grains burning system. Background Art

[0002] Biomass is a clean, renewable resource with low nitrogen and sulfur content, a large total volume, and is readily available and inexpensive. Its utilization and conversion methods are highly compatible with fossil energy sources, and its utilization process has the advantage of near-zero CO2 emissions. In large coal-fired power plants, the blending of a certain proportion of biomass into coal-fired boilers can reduce the plant's fuel costs, effectively offset tight coal supply, and improve the economic efficiency of power plant operations. Furthermore, blending biomass into coal-fired boilers can effectively reduce emissions of pollutants such as NOx and SOx, as well as greenhouse gases (CO2, CH4, etc.), lowering the cost of pollution control, with significant environmental and social benefits.

[0003] Compared to pure biomass power generation technology, co-firing technology fully utilizes existing equipment and offers lower investment costs per unit of power. Furthermore, boilers using pure biomass are typically not suitable for long-distance transportation due to the biomass's low energy density, irregular shape, high porosity, and low calorific value. This can lead to significant calorific value fluctuations at the boiler entrance and unstable combustion. Furthermore, the supply of biomass fuel is subject to seasonal and regional fluctuations, making it difficult to ensure a continuous and stable supply, making its efficiency and economical performance difficult to guarantee. Co-firing technology leverages the economies of scale of large power plants and can achieve power generation efficiencies of approximately 38%, while pure biomass boilers typically only have an efficiency of around 25%. Therefore, blending biomass into coal-fired boilers offers low technical upgrade costs, minimal project investment risk, and high power generation efficiency, making it a low-cost and low-risk combustion method at this stage. In many countries, co-firing remains the most economical technology option for achieving CO2 emission reduction targets. Currently, biomass blending is primarily done manually, resulting in relatively low combustion efficiency and automation levels. Summary of the Invention

[0004] The present invention aims to solve the technical problems in the prior art of relatively low combustion economy and automation level when biomass is mixed with fuel in combustion, and provides a system for mixing distiller's grains with pulverized coal boiler.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A pulverized coal blending and burning distiller's grains system, comprising: a coal conveyor, at least one coal bunker, a distiller's grains conveying device, at least one distiller's grains bunker, a first coal mill, a second coal mill, a distiller's grains blending and burning controller, a first pulverized coal feeder, a second pulverized coal feeder, a blending and burning air supply mechanism, and a furnace;

[0007] The coal conveyor is connected to the coal bunker; the coal bunker is connected to the first coal pulverizer via the first coal mill, and the first coal pulverizer is connected to the furnace; the coal bunker is connected to the second coal pulverizer; the distiller's grains conveying device is connected to the distiller's grains bunker; the distiller's grains bunker is connected to the second coal pulverizer; the second coal pulverizer is connected to the furnace via the second coal pulverizer;

[0008] The mixed combustion air supply mechanism is connected to the furnace;

[0009] The distiller's grains co-firing controller is electrically connected to the second coal mill.

[0010] Furthermore, the controller includes:

[0011] A storage unit for storing a custom fuel specification sheet; the custom fuel specification sheet includes: raw coal quality number, distiller's grains quality number, distiller's grains blending ratio, raw coal price, and distiller's grains price;

[0012] A human-computer interaction device for setting or modifying control parameters of the distiller's grains blending controller, manually selecting, and issuing instructions for retrieving custom fuel specifications;

[0013] A control unit is used to obtain a call instruction from the human-computer interaction device, obtain the corresponding custom fuel label from the storage unit according to the call instruction, read the information of the raw coal quality number and the distiller's grains quality number in the custom fuel label, and control the opening of the coal bin and distiller's grains bin of corresponding quality; read the distiller's grains blending ratio information in the custom fuel label, and control the amount of raw coal and distiller's grains taken by the second coal mill.

[0014] Furthermore, the controller further includes:

[0015] The parameter modification unit is used to modify the parameter information in the custom fuel specification sheet obtained from the storage unit.

[0016] Furthermore, the distiller's grains co-combustion controller further includes:

[0017] The self-learning unit is used to record the fuel specification sheet used in each blending and combustion control process, and store the recorded fuel specification sheet information in the storage unit to form a historical fuel specification sheet.

[0018] Furthermore, the controller further includes:

[0019] The competitive optimization unit is used to collect the raw coal quality number, distiller's grains quality number, raw coal and distiller's grains ratio, raw coal price and distiller's grains price currently input into the second coal mill in automatic mode, automatically summarize and weight them to obtain a real-time fuel bill; compare the real-time fuel bill with the historical fuel bills stored in the storage unit, obtain the fuel bill with the best comprehensive benefits and send it to the control unit.

[0020] Furthermore, the controller further includes:

[0021] The temperature control unit is used to obtain the outlet temperature of the second coal mill and compare the outlet temperature with the preset alarm temperature value and the stop temperature value; the alarm temperature value is lower than the stop temperature value; if the outlet temperature value is less than the alarm temperature value, the temperature control unit does not apply an adjustment signal; if the outlet temperature is greater than or equal to the alarm temperature value, and the outlet temperature value is less than the stop temperature value, the temperature control unit sends a control signal to control the alarm to sound an alarm; if the outlet temperature is greater than or equal to the stop temperature value, the temperature control unit sends a control signal to control the second coal mill to stop working.

[0022] Furthermore, when the outlet temperature is greater than or equal to the alarm temperature value and the outlet temperature value is less than the stop temperature value, the temperature control unit controls the inlet of the second coal mill to increase the cold air damper or decrease the hot air damper to reduce the outlet air temperature of the second coal mill.

[0023] Furthermore, the controller further includes:

[0024] The air-coal ratio control unit is used to obtain the current combustion material flow information from the inlet of the coal feeding mechanism, and control the air volume of the air supply mechanism in real time according to the set furnace air intake and combustion material ratio.

[0025] The coal powder mixed with distiller's grains system provided by the present invention has at least the following beneficial effects or advantages:

[0026] The pulverized coal and distiller's grains system provided by the present invention has a coal conveyor connected to the coal bunker; the coal bunker is connected to the first pulverizer through the first pulverizer, the first pulverizer is connected to the furnace; the coal bunker is connected to the second pulverizer; the distiller's grains conveying device is connected to the distiller's grains bunker; the distiller's grains bunker is connected to the second pulverizer; the second pulverizer is connected to the furnace through the second pulverizer; the blending and air supply mechanism is connected to the furnace; and the distiller's grains blending controller is electrically connected to the second pulverizer. The pulverized coal and distiller's grains system provided by the present invention can achieve precise blending of the fuel entering the furnace. The distiller's grains blending controller can achieve online adjustment of the parameters of the distiller's grains bunker, the coal bunker, and the corresponding second pulverizer pulverizing system, and the adjustment is flexible. Blending and adjustment can be carried out according to real-time information on the fuel entering the furnace, with strong pertinence, improving the boiler's adaptability to the fuel, and maintaining high economy and stability during flexible unit operation and multi-fuel blending. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the structure of a coal powder mixed with distiller's grains system provided in an embodiment of the present invention;

[0028] Figure 2This is a schematic diagram of the internal structure of the distiller's grains co-firing controller provided in an embodiment of the present invention.

[0029] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0030] 1-coal conveyor, 2-coal bunker, 3-first coal pulverizer, 4-still lees conveying device, 5-still lees bunker, 6-second coal mill, 7-second coal pulverizer, 8-first coal mill, 9-furnace, 10-coal co-firing air supply mechanism, 11-still lees co-firing controller. DETAILED DESCRIPTION

[0031] The present invention aims to solve the technical problems in the prior art of relatively low combustion economy and automation level when biomass is mixed with fuel in combustion, and provides a system for mixing distiller's grains with pulverized coal boiler.

[0032] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] See also Figure 1 Distillers grains have a high fiber content, a fluffy texture, low density, low calorific value, and a high volatile content, accounting for approximately 70%, and they pyrolyze rapidly. Coal, on the other hand, is the opposite: it is mostly fixed carbon, with a volatile content generally below 35%. When biomass is fed into the furnace, the high temperatures create a large amount of volatiles that precipitate. This release creates a porous, loose structure, which reduces resistance to oxygen diffusion into the particles and combustion products diffusion outward, resulting in faster combustion. Distillers grains combustion primarily involves the combustion of volatiles, which rise rapidly after precipitation, shifting the primary heat exchange zone upward and even causing excessive heat and corrosion in superheaters. Compared to distillers grains biomass, pulverized coal exhibits a more stable ignition, combustion, and burnout process. When distillers grains are added to pulverized coal, some pulverized coal particles are dragged along with the biomass fuel, enhancing combustion. Furthermore, the reducing components in the distillers grains fuel have a certain effect on suppressing nitrogen oxides. Therefore, directly mixing the naturally dried distiller's grains biomass with coal, and sending the coal powder and distiller's grains mixture into the furnace for combustion by regulating the pulverizing system of the pulverizer, is an economical and effective way to reduce pollutant emissions from pulverized coal boilers and to dispose of local biomass distiller's grains in a high-value manner.

[0034] Based on the above analysis, the embodiment of the present invention provides a system for burning lees mixed with pulverized coal boiler, see Figure 1 and Figure 2The system primarily includes: a coal conveyor 1, at least one coal bunker 2, a distiller's grains conveying device 4, at least one distiller's grains bunker 5, a first coal mill 8, a second coal mill 6, a distiller's grains co-combustion controller 11, a first pulverized coal feeder 3, a second pulverized coal feeder 7, a co-combustion air supply mechanism 10, and a furnace 9. The coal conveyor 1 is connected to the coal bunker 2, which is connected to the first pulverized coal feeder 3 via the first coal mill 8, and the first pulverized coal feeder 3 is connected to the furnace 9. The coal bunker 2 is connected to the second pulverized coal feeder 6; the distiller's grains conveying device 4 is connected to the distiller's grains bunker 5; the distiller's grains bunker 5 is connected to the second pulverized coal feeder 6; the second pulverized coal feeder 6 is connected to the furnace 9 via the second pulverized coal feeder 7. The co-combustion air supply mechanism 10 is connected to the furnace 9; and the distiller's grains co-combustion controller 11 is electrically connected to the second pulverized coal feeder 6.

[0035] In the embodiment of the present invention, see Figure 2 The distiller's grains blending controller 11 includes:

[0036] A storage unit is used to store custom fuel specifications. Custom fuel specifications include: raw coal quality number, distiller's grains quality number, distiller's grains blending ratio, raw coal price, and distiller's grains price. Multiple custom fuel specifications can be set, each with different parameters. For example, raw coal can be categorized as A, B, C, and D based on quality from best to worst; distiller's grains can be categorized as a, b, c, and d based on quality from best to worst; the distiller's grains blending ratio is S%; the raw coal price is P; and the distiller's grains price is p. A custom fuel specification can be represented by an array containing the above parameters, for example (A, b, m:n, P, p), where S% = 5% to 7.5%. If a component is absent, it is represented by 0.

[0037] The human-computer interaction device is used to set or modify the control parameters of the distiller's grains blending controller 11, manually select and issue a call instruction for a custom fuel specification. In the embodiment of the present invention, the human-computer interaction device is an HMI device.

[0038] The control unit is used to obtain a call instruction from the human-computer interaction device, obtain the corresponding custom fuel label from the storage unit according to the call instruction, read the information of the raw coal quality number and the distiller's grains quality number in the custom fuel label, and control the opening of the coal bin 2 and distiller's grains bin 5 of the corresponding quality; read the distiller's grains blending ratio information in the custom fuel label, and control the second pulverizer 6 to take in the amount of raw coal and distiller's grains.

[0039] The parameter modification unit is used to modify the parameter information in the custom fuel specification sheet obtained from the storage unit.

[0040] In a preferred embodiment provided by the present invention, in order to achieve automatic control of fuel and further optimize the fuel control process, in the embodiment of the present invention, the distiller's grains co-combustion controller 11 further includes:

[0041] The self-learning unit is used to record the fuel standard sheet used in each blending control process, and store the recorded fuel standard sheet information in the storage unit to form a historical fuel standard sheet.

[0042] The optimization unit is used to automatically collect the raw coal quality number, distiller's grains quality number, raw coal to distiller's grains ratio, raw coal price, and distiller's grains price currently input to the second coal mill 6, automatically aggregate and weight them to obtain a real-time fuel price list; compare the real-time fuel price list with the historical fuel price lists stored in the storage unit, and obtain the fuel price list with the best overall benefit, which is then sent to the control unit for execution. The calculation rules for the overall benefit can be set as needed, including considerations such as calorific value and cost.

[0043] In a preferred solution provided by an embodiment of the present invention, a temperature alarm mechanism is further provided. Specifically, the distiller's grains co-combustion controller 11 further includes:

[0044] The temperature control unit is used to obtain the outlet temperature of the second coal mill 6 and compare the outlet temperature with a preset alarm temperature value (e.g., 85°C) and a shutdown temperature value (e.g., 90°C). The alarm temperature value is lower than the shutdown temperature value. If the outlet temperature value is lower than the alarm temperature value, the temperature control unit does not apply an adjustment signal. If the outlet temperature is greater than or equal to the alarm temperature value, and the outlet temperature value is lower than the shutdown temperature value, the temperature control unit sends a control signal to control the alarm device to sound an alarm. At the same time, the temperature control unit sends a control signal to control the second coal mill inlet to increase the cold air damper or decrease the hot air damper to reduce the air temperature at the second coal mill outlet. If the outlet temperature is greater than or equal to the shutdown temperature value, the temperature control unit sends a control signal to control the second coal mill 6 to stop working. When the outlet temperature is greater than or equal to the alarm temperature value, and the outlet temperature value is lower than the shutdown temperature value, the temperature control unit controls the hot and cold air blowers installed at the inlet of the second coal mill 6 to increase the cold air output to reduce the temperature.

[0045] In the embodiment of the present invention, in order to improve combustion economy and achieve precise control of fuel and air volume, the distiller's grains co-combustion controller 11 further includes:

[0046] The air-coal ratio control unit is used to obtain the current combustion material flow information from the inlet of the coal feeding mechanism 8, and control the air volume of the blending air supply mechanism 10 in real time according to the set ratio of the furnace 9 air inlet volume to the combustion material.

[0047] The coal powder mixed with distiller's grains system provided by the embodiment of the present invention has at least the following beneficial effects or advantages:

[0048] The pulverized coal and distiller's grains system provided by the embodiment of the present invention comprises the following: a coal conveyor connected to a coal bunker; a coal bunker connected to a first pulverizer through a first pulverizer, and a first pulverizer connected to a furnace; a coal bunker connected to a second pulverizer; a distiller's grains conveying device connected to a distiller's grains bunker; a distiller's grains bunker connected to a second pulverizer; a second pulverizer connected to a furnace through a second pulverizer; a pulverizer and air supply mechanism connected to the furnace; and a distiller's grains pulverization controller electrically connected to the second pulverizer. The pulverized coal and distiller's grains system provided by the embodiment of the present invention can achieve precise blending of the fuel entering the furnace. The distiller's grains pulverization controller can achieve online adjustment of the parameters of the distiller's grains bunker, the coal bunker, and the corresponding second pulverizer pulverization system, with flexible adjustment. Blending and adjustment can be made based on real-time information on the fuel entering the furnace, with strong pertinence, thereby improving the boiler's adaptability to fuel and maintaining high economy and stability during flexible unit operation and multi-fuel blending.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for mixing pulverized coal with distiller's grains, characterized in that: include: Coal conveyor, at least one coal bunker, distiller's grains conveying device, at least one distiller's grains bunker, a first coal mill, a second coal mill, a distiller's grains co-firing controller, a first pulverized coal feeder, a second pulverized coal feeder, a co-firing air supply mechanism and a furnace; The coal conveyor is connected to the coal bunker; the coal bunker is connected to the first coal pulverizer via the first coal mill, and the first coal pulverizer is connected to the furnace; the coal bunker is connected to the second coal pulverizer; the distiller's grains conveying device is connected to the distiller's grains bunker; the distiller's grains bunker is connected to the second coal pulverizer; the second coal pulverizer is connected to the furnace via the second coal pulverizer; The mixed combustion air supply mechanism is connected to the furnace; The distiller's grains co-firing controller is electrically connected to the second coal mill; The controller includes: A storage unit for storing a custom fuel specification sheet; the custom fuel specification sheet includes: raw coal quality number, distiller's grains quality number, distiller's grains blending ratio, raw coal price, and distiller's grains price; A human-computer interaction device for setting or modifying control parameters of the distiller's grains blending controller, manually selecting, and issuing instructions for retrieving custom fuel specifications; A control unit is used to obtain a call instruction from the human-computer interaction device, obtain the corresponding custom fuel label from the storage unit according to the call instruction, read the information of the raw coal quality number and the distiller's grains quality number in the custom fuel label, and control the opening of the coal bin and distiller's grains bin of corresponding quality; read the distiller's grains blending ratio information in the custom fuel label, and control the amount of raw coal and distiller's grains taken by the second coal mill.

2. The pulverized coal mixed with distiller's grains system according to claim 1, characterized in that: The controller further includes: The parameter modification unit is used to modify the parameter information in the custom fuel specification sheet obtained from the storage unit.

3. The pulverized coal mixed with distiller's grains system according to claim 2, characterized in that: The distiller's grains blending controller also includes: The self-learning unit is used to record the fuel specification sheet used in each blending and combustion control process, and store the recorded fuel specification sheet information in the storage unit to form a historical fuel specification sheet.

4. The pulverized coal mixed with distiller's grains system according to claim 3, characterized in that: The controller further includes: The competitive optimization unit is used to collect the raw coal quality number, distiller's grains quality number, raw coal and distiller's grains ratio, raw coal price and distiller's grains price currently input into the second coal mill in automatic mode, automatically summarize and weight them to obtain a real-time fuel bill; compare the real-time fuel bill with the historical fuel bills stored in the storage unit, obtain the fuel bill with the best comprehensive benefits and send it to the control unit.

5. The pulverized coal mixed with distiller's grains system according to any one of claims 1 to 4, characterized in that: The controller further includes: The temperature control unit is used to obtain the outlet temperature of the second coal mill and compare the outlet temperature with the preset alarm temperature value and the stop temperature value; the alarm temperature value is lower than the stop temperature value; if the outlet temperature value is less than the alarm temperature value, the temperature control unit does not apply an adjustment signal; if the outlet temperature is greater than or equal to the alarm temperature value, and the outlet temperature value is less than the stop temperature value, the temperature control unit sends a control signal to control the alarm to sound an alarm; if the outlet temperature is greater than or equal to the stop temperature value, the temperature control unit sends a control signal to control the second coal mill to stop working.

6. The pulverized coal mixed with distiller's grains system according to claim 5, characterized in that: When the outlet temperature is greater than or equal to the alarm temperature value and the outlet temperature value is less than the stop temperature value, the temperature control unit controls the second coal mill inlet to increase the cold air damper or decrease the hot air damper to reduce the outlet air temperature of the second coal mill.

7. The pulverized coal mixed with distiller's grains system according to any one of claims 1 to 4, characterized in that: The controller further includes: The air-coal ratio control unit is used to obtain the current combustion material flow information from the coal feeding mechanism entrance, and control the air volume of the air supply mechanism in real time according to the set furnace air intake and combustion material ratio.

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