A lignite circulating fluidized bed quality upgrading and drying system

Abstract

The invention discloses a lignite circulating fluidized bed upgrading and drying system, which relates to the field of material processing technology. The main technical problem to be solved is: the lignite upgrading and drying process has the following points to note: lignite is a flammable and explosive item and is in a high-temperature heating state for a long time. How to ensure the stability of the lignite? In step three, the heating equipment adopts a carbon dioxide heat pump dryer, and the heating component discharges the heated carbon dioxide gas into the fluidized bed. The carbon dioxide heat pump dryer uses the high-temperature exhaust gas of burnt lime to dry the lignite; in step four, after carbon dioxide drying, a first-level upgraded lignite lump is obtained; in step five, a stone powder box is arranged above the fluidized bed, with the opening of the stone powder box facing downward, and the stone powder box is filled with stone powder. A fire alarm is installed on the fluidized bed, and the fire alarm is connected to the stone powder box, so that the stone powder is used to achieve the purpose of fire extinguishing.

Description

Technical Field

[0001] The present invention relates to the technical field of material processing, in particular to a lignite circulating fluidized bed upgrading and drying system. Background Art

[0002] The circulating fluidized bed uses limestone furnace combustion. Lignite enters the equipment and moves in the furnace to be heated. Hot air passes through the fluidized bed and exchanges heat with the wet lignite. The wet air is removed from the cyclone separator and discharged from the exhaust port. After a continuous drying process, the lignite reaches the drying standard and is discharged from the discharge port.

[0003] The key point to note in the lignite upgrading and drying process is that lignite is a flammable and explosive item and is in a high-temperature heating state for a long time. How to ensure the stability of lignite? Therefore, it is necessary to design a lignite circulating fluidized bed upgrading and drying system. Summary of the Invention

[0004] The object of the present invention is to provide a lignite circulating fluidized bed upgrading and drying system to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a lignite circulating fluidized bed upgrading and drying system, wherein the lignite upgrading and drying process comprises the following steps:

[0006] In step 1, an appropriate amount of lignite is selected from the lignite raw materials and fed into the crushing equipment. The lignite is crushed and dispersed by the crushing equipment to improve the uniformity of the lignite. Before the lignite is crushed, the humidity of the agglomerated lignite blocks is tested, and the humidity data of the lignite is recorded and transmitted to the fluidized bed quality improvement and drying system. The humidity detector is installed on the front transport equipment of the fluidized bed and is electrically connected to the circulating fluidized bed quality improvement and drying system.

[0007] Step 2: The lignite enters the fluidized bed, and the heating equipment below the lignite is started. The dry hot air generated by the heating equipment is blown upwards to the fluidized bed to perform a heat exchange process with the lignite.

[0008] Step 3: The heating equipment uses a carbon dioxide heat pump dryer. The heating component discharges the heated carbon dioxide gas into the fluidized bed. The carbon dioxide heat pump dryer uses the high-temperature exhaust gas from burning lime to dry the lignite.

[0009] Step 4: drying with carbon dioxide to obtain first-grade upgraded lignite lump coal;

[0010] Step 5: Set a stone powder box above the fluidized bed with the opening facing downward, fill the stone powder box with stone powder, install a fire alarm on the fluidized bed, and connect the fire alarm to the stone powder box.

[0011] According to the above technical solution, the fluidized bed upgrading and drying system is connected to a professional visual module, which is a camera assembly installed at the fluidized bed inlet and outlet ends. The camera assembly is aimed at the lignite that is about to enter the fluidized bed. The lignite that is about to enter the fluidized bed contains lignite blocks. The camera assembly sends a confirmation instruction to the fluidized bed upgrading and drying system. The fluidized bed upgrading and drying system responds to the confirmation instruction, and the movement of the lignite into the fluidized bed is suspended until the lignite blocks are removed. The removal of the lignite is manually controlled. After the lignite blocks are removed, the lignite begins to continue entering the fluidized bed.

[0012] When the amount of lignite entering the fluidized bed reaches a preset value, the channel entering the fluidized bed is cut off and step 2 is started;

[0013] The camera assembly installed at the lignite discharge outlet transmits the image of the dried lignite to the fluidized bed upgrading and drying system. The fluidized bed upgrading and drying system receives the image information and stores it for comparison with the camera image before the lignite enters the fluidized bed.

[0014] According to the above technical solution, the heating process of the fluidized bed includes two stages: preheating and auxiliary heating. In the preheating stage, after the amount of lignite entering the fluidized bed is set in the circulating fluidized bed upgrading and drying system, the carbon dioxide heat pump dryer enters the preheating state. In the preheating state, the preheating temperature is N, the N value is fixed, and the preheating time is H, the H value is fixed. The purpose of preheating is to raise the temperature of the fluidized bed itself to the temperature required for upgrading and drying before the lignite enters.

[0015] When the fluidized bed upgrading and drying enters the final stage, the circulating fluidized bed upgrading and drying system is connected to auxiliary heating to increase the heating temperature to ensure that all lignite completes the upgrading and drying process.

[0016] According to the above technical solution, the stone powder box startup conditions in step 5 are: fire occurs and lignite moisture exceeds the standard;

[0017] The critical value of lignite moisture is K. If the moisture of the lignite entering the fluidized bed is higher than the K value, stone powder is sprinkled on the surface of the lignite after entering the fluidized bed. The circulating fluidized bed quality improvement and drying system receives the signal transmitted by the moisture detector and sends it to execute step five. The stone powder box in step five opens and sprays an appropriate amount of stone powder. The stone powder is sprinkled on the surface of the lignite. The stone powder uses its water absorption performance to quickly remove the moisture from the surface of the lignite. The stone powder absorbs water and then passes through the carbon dioxide heat pump dryer to form a layer of stone powder shell on the surface of the lignite.

[0018] If the moisture content of the lignite entering the fluidized bed is lower than the K value, no stone powder needs to be added;

[0019] If a fire occurs in the lignite in the fluidized bed, the fire alarm sends a fire command to the circulating fluidized bed upgrading and drying system. The circulating fluidized bed upgrading and drying system responds to the command, drives the stone powder box to open, and continuously sprays out stone powder.

[0020] According to the above technical solution, a pipeline for introducing nitrogen is set in the fluidized bed, the pipeline is connected to the nitrogen source, and a valve is set in the pipeline. After the fire alarm sends a fire command to the circulating fluidized bed upgrading and drying system, the circulating fluidized bed upgrading and drying system simultaneously arranges the valve to open and discharge nitrogen into the fluidized bed, using nitrogen as a flame retardant.

[0021] According to the above technical solution, when the lignite upgrading and drying process is carried out, heat energy is exchanged with the high-temperature gas. The external exhaust pump on one side of the fluidized bed discharges the high-temperature gas containing moisture into the transfer tower, and then enters the cooling tower through the transfer tower. After being cooled in the cooling tower, it enters the drying tower. The moisture inside the gas is removed by drying in the drying tower, and the remaining dry carbon dioxide gas is discharged into the carbon dioxide heat pump dryer again. After being heated again by the carbon dioxide heat pump dryer, it continues to serve as a medium for lignite upgrading and drying.

[0022] According to the above technical solution, a continuous curved pipe is arranged in the transfer tower. The gas passing through the drying tower can enter the carbon dioxide heat pump dryer only through the continuous curved pipe. The high-temperature gas discharged from the fluidized bed heats up the transfer tower, causing the temperature inside the transfer tower to be high, and then heats the continuous curved pipe. The gas temperature passing through the drying tower is low, and the gas temperature is increased through this section of movement path through the continuous curved pipe in the transfer tower. When the gas enters the carbon dioxide heat pump dryer, there is no need to consume a small amount of heat energy in the carbon dioxide heat pump dryer, which achieves the effect of energy saving and emission reduction. If the gas passing through the drying tower is directly passed into the carbon dioxide heat pump dryer, the temperature inside the carbon dioxide heat pump dryer will drop, and the carbon dioxide heat pump dryer needs to increase its operating power to ensure the normal drying efficiency of the lignite.

[0023] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention is provided with a carbon dioxide heat pump dryer, the heating equipment adopts the carbon dioxide heat pump dryer, the heating component discharges the heated carbon dioxide gas into the fluidized bed, and the carbon dioxide heat pump dryer adopts the high-temperature exhaust gas of burning lime to dry the lignite, thereby reducing the probability of lignite combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 This is a flow chart of the movement of high-temperature gas discharged from the fluidized bed of the present invention;

[0026] The three elliptical towers from left to right are the transfer tower, cooling tower and drying tower. Implementation Method

[0027] The following will clearly and completely describe 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] See also Figure 1 The present invention provides a technical solution: a lignite circulating fluidized bed upgrading and drying system, wherein the lignite upgrading and drying process comprises the following steps:

[0029] In step 1, an appropriate amount of lignite is selected from the lignite raw materials and fed into the crushing equipment. The lignite is crushed and dispersed by the crushing equipment to improve the uniformity of the lignite. Before the lignite is crushed, the humidity of the agglomerated lignite blocks is tested, and the humidity data of the lignite is recorded and transmitted to the fluidized bed quality improvement and drying system. The humidity detector is installed on the front transport equipment of the fluidized bed and is electrically connected to the circulating fluidized bed quality improvement and drying system.

[0030] Step 2: The lignite enters the fluidized bed, and the heating equipment below the lignite is started. The dry hot air generated by the heating equipment is blown upwards to the fluidized bed to perform a heat exchange process with the lignite.

[0031] Step 3: The heating equipment uses a carbon dioxide heat pump dryer. The heating component discharges the heated carbon dioxide gas into the fluidized bed. The carbon dioxide heat pump dryer uses the high-temperature exhaust gas from burning lime to dry the lignite.

[0032] Step 4: drying with carbon dioxide to obtain first-grade upgraded lignite lump coal;

[0033] Step 5: Set a stone powder box above the fluidized bed with the opening facing downward, fill the stone powder box with stone powder, install a fire alarm on the fluidized bed, and connect the fire alarm to the stone powder box.

[0034] The fluidized bed upgrading and drying system is connected to a professional vision module. The vision module is a camera assembly installed at the fluidized bed inlet and outlet ends. The camera assembly is aimed at the lignite entering the fluidized bed. The pre-entered lignite contains lignite lumps. The camera assembly sends a confirmation command to the fluidized bed upgrading and drying system. The fluidized bed upgrading and drying system responds to the confirmation command, and the movement of the lignite into the fluidized bed is suspended until the lignite lumps are removed. The removal of the lignite is manually controlled. After the lignite lumps are removed, the lignite continues to enter the fluidized bed.

[0035] When the amount of lignite entering the fluidized bed reaches a preset value, the passage into the fluidized bed is cut off and step 2 is started;

[0036] The camera assembly installed at the lignite discharge outlet transmits the image of the dried lignite to the fluidized bed upgrading and drying system. The fluidized bed upgrading and drying system receives the image information and stores it for comparison with the camera image before the lignite enters the fluidized bed.

[0037] The heating process of the fluidized bed includes two stages: preheating and auxiliary heating. In the preheating stage, after the amount of lignite entering the fluidized bed is set in the circulating fluidized bed upgrading and drying system, the carbon dioxide heat pump dryer enters the preheating state. In the preheating state, the preheating temperature is N, and the N value is fixed. The preheating time is H, and the H value is fixed. The purpose of preheating is to raise the temperature of the fluidized bed itself to the temperature required for upgrading and drying before the lignite enters, ensuring that the lignite is dried immediately after entering. The temperature of the fluidized bed itself is low. After the lignite enters, the surface of the lignite cannot be dried immediately. During the slow drying process, the surface of the lignite solidifies, resulting in low drying efficiency inside the lignite.

[0038] When the fluidized bed upgrading and drying enters the final stage, the circulating fluidized bed upgrading and drying system is connected to auxiliary heating to increase the heating temperature to ensure that all lignite completes the upgrading and drying process.

[0039] The stone powder box activation conditions in step 5 are: fire occurs and lignite moisture exceeds the standard;

[0040] The critical value of lignite moisture is K. If the moisture of the lignite entering the fluidized bed is higher than the K value, stone powder is sprinkled on the surface of the lignite after entering the fluidized bed. The circulating fluidized bed quality improvement and drying system receives the signal transmitted by the humidity detector and sends it to execute step five. The stone powder box in step five opens and sprays an appropriate amount of stone powder. The stone powder is sprinkled on the surface of the lignite. The stone powder uses its water absorption performance to quickly remove the moisture on the surface of the lignite. The stone powder absorbs water and then passes through the carbon dioxide heat pump dryer to form a layer of stone powder shell on the surface of the lignite. Wait for the lignite to complete the quality improvement and drying process and remove the stone powder shell.

[0041] If the moisture content of the lignite entering the fluidized bed is lower than the K value, no stone powder needs to be added;

[0042] If a fire occurs in the lignite in the fluidized bed, the fire alarm will send a fire command to the circulating fluidized bed upgrading and drying system. The circulating fluidized bed upgrading and drying system will respond to the command, drive the stone powder box to open, and continuously spray stone powder to extinguish the fire using the flame retardant properties of the stone powder.

[0043] A pipeline for introducing nitrogen is set in the fluidized bed, and the pipeline is connected to the nitrogen source. A valve is installed in the pipeline. After the fire alarm sends a fire command to the circulating fluidized bed upgrading and drying system, the circulating fluidized bed upgrading and drying system simultaneously arranges the valve to open and discharge nitrogen into the fluidized bed. Nitrogen is used for flame retardant to prevent the fire from overflowing the fluidized bed. At the same time, multiple fire extinguishing methods such as nitrogen and stone powder are carried out simultaneously to further ensure the drying stability of the lignite in the fluidized bed.

[0044] During the lignite upgrading and drying process, heat energy is exchanged with the high-temperature gas. The external exhaust pump on one side of the fluidized bed discharges the high-temperature gas containing moisture into the transfer tower, which then enters the cooling tower. After being cooled in the cooling tower, the gas enters the drying tower. The moisture inside the gas is removed by drying in the drying tower, and the remaining dry carbon dioxide gas is discharged into the carbon dioxide heat pump dryer again. After being heated again by the carbon dioxide heat pump dryer, it continues to serve as the medium for lignite upgrading and drying, thereby reducing the amount of lime burned and the cost of lignite drying.

[0045] A continuous curved pipe is set in the transfer tower. The gas passing through the drying tower can enter the carbon dioxide heat pump dryer through the continuous curved pipe. The high-temperature gas discharged from the fluidized bed heats up the transfer tower, causing the temperature inside the transfer tower to be high, and then heats the continuous curved pipe. The gas temperature passing through the drying tower is low. The gas temperature rises during the movement path through the continuous curved pipe in the transfer tower. When the gas enters the carbon dioxide heat pump dryer, it does not consume a small amount of heat energy in the carbon dioxide heat pump dryer, which achieves the effect of energy saving and emission reduction. If the gas passing through the drying tower is directly introduced into the carbon dioxide heat pump dryer, the temperature inside the carbon dioxide heat pump dryer will drop, and the carbon dioxide heat pump dryer needs to increase its operating power to ensure the normal drying efficiency of the lignite.

[0046] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0047] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for upgrading and drying lignite in a circulating fluidized bed, characterized in that: The process of lignite upgrading and drying includes the following steps: In step 1, an appropriate amount of lignite is selected from the lignite raw materials and enters the crushing equipment, where it is crushed and dispersed. Before the lignite is crushed, the humidity of the agglomerated lignite blocks is tested, and the humidity data of the lignite is recorded and transmitted to the fluidized bed upgrading and drying system. The humidity detector is installed on the front transport equipment of the fluidized bed, and the humidity detector is electrically connected to the circulating fluidized bed upgrading and drying system. Step 2: The lignite enters the fluidized bed, and the heating equipment below the lignite is started. The dry hot air generated by the heating equipment is blown upwards to the fluidized bed to perform a heat exchange process with the lignite. Step 3: The heating equipment uses a carbon dioxide heat pump dryer. The heating component discharges the heated carbon dioxide gas into the fluidized bed. The carbon dioxide heat pump dryer uses the high-temperature exhaust gas from burning lime to dry the lignite. Step 4: drying with carbon dioxide to obtain first-grade upgraded lignite lump coal; Step 5: a stone powder box is placed above the fluidized bed with its opening facing downward, the stone powder box is filled with stone powder, a fire alarm is installed on the fluidized bed, and the fire alarm is connected to the stone powder box; The stone powder box start-up conditions in step 5 are: fire occurs and lignite moisture exceeds the standard; The critical value of lignite moisture is K. If the moisture of the lignite entering the fluidized bed is higher than the K value, stone powder is sprinkled on the surface of the lignite after entering the fluidized bed. The circulating fluidized bed quality-enhancing and drying system receives the signal transmitted by the humidity detector and sends it to execute step five. The stone powder box in step five opens and sprays an appropriate amount of stone powder. The stone powder is sprinkled on the surface of the lignite. The stone powder uses its water-absorbing property to quickly remove the moisture from the surface of the lignite. The stone powder absorbs water and then passes through the carbon dioxide heat pump dryer to form a layer of stone powder shell on the surface of the lignite. Wait until the lignite completes the quality-enhancing and drying process to remove the stone powder shell. If the moisture content of the lignite entering the fluidized bed is lower than the K value, no stone powder needs to be added; If a fire occurs in the lignite in the fluidized bed, the fire alarm sends a fire command to the circulating fluidized bed upgrading and drying system. The circulating fluidized bed upgrading and drying system responds to the command, drives the stone powder box to open, and continuously sprays out stone powder.

2. The method for upgrading and drying lignite in a circulating fluidized bed according to claim 1, wherein: The fluidized bed upgrading and drying system is connected to a professional visual module, which is a camera assembly installed at the fluidized bed inlet and outlet ends. The camera assembly is aimed at the lignite that is about to enter the fluidized bed. The lignite that is about to enter the fluidized bed contains lignite blocks. The camera assembly sends a confirmation instruction to the fluidized bed upgrading and drying system. The fluidized bed upgrading and drying system responds to the confirmation instruction, and the movement of the lignite into the fluidized bed is suspended until the lignite blocks are removed. The removal of the lignite is manually controlled. After the lignite blocks are removed, the lignite continues to enter the fluidized bed. When the amount of lignite entering the fluidized bed reaches a preset value, the channel entering the fluidized bed is cut off and step 2 is started; The camera assembly installed at the lignite discharge outlet transmits the image of the dried lignite to the fluidized bed upgrading and drying system. The fluidized bed upgrading and drying system receives the image information and stores it for comparison with the camera image before the lignite enters the fluidized bed.

3. The method for upgrading and drying lignite in a circulating fluidized bed according to claim 2, characterized in that: The heating process of the fluidized bed includes two stages: preheating and auxiliary heating. In the preheating stage, after the amount of lignite entering the fluidized bed is set in the circulating fluidized bed upgrading and drying system, the carbon dioxide heat pump dryer enters the preheating state. In the preheating state, the preheating temperature is N, which is a fixed value, and the preheating time is H, which is a fixed value. The purpose of preheating is to raise the temperature of the fluidized bed itself to the temperature required for upgrading and drying before the lignite enters. When the fluidized bed upgrading and drying enters the final stage, the circulating fluidized bed upgrading and drying system is connected to auxiliary heating to increase the heating temperature to ensure that all lignite completes the upgrading and drying process.

4. The method for upgrading and drying lignite in a circulating fluidized bed according to claim 3, characterized in that: A pipeline for introducing nitrogen is set in the fluidized bed, the pipeline is connected to the nitrogen source, and a valve is set in the pipeline. After the fire alarm sends a fire command to the circulating fluidized bed upgrading and drying system, the circulating fluidized bed upgrading and drying system simultaneously arranges the valve to open and discharge nitrogen into the fluidized bed to use nitrogen for flame retardancy.

5. The method for upgrading and drying lignite in a circulating fluidized bed according to claim 4, characterized in that: During the lignite upgrading and drying process, heat energy is exchanged with the high-temperature gas. The external exhaust pump on one side of the fluidized bed discharges the high-temperature gas containing moisture into the transfer tower, which then enters the cooling tower. After being cooled in the cooling tower, the gas enters the drying tower. The moisture inside the gas is removed by drying in the drying tower, and the remaining dry carbon dioxide gas is discharged into the carbon dioxide heat pump dryer again. After being heated again by the carbon dioxide heat pump dryer, it continues to serve as the medium for lignite upgrading and drying.

6. The method for upgrading and drying lignite in a circulating fluidized bed according to claim 5, characterized in that: A continuous curved pipe is arranged in the transfer tower. The gas passing through the drying tower can enter the carbon dioxide heat pump dryer only through the continuous curved pipe. The high-temperature gas discharged from the fluidized bed heats up the transfer tower, causing the temperature inside the transfer tower to be high, and then heats the continuous curved pipe. The temperature of the gas passing through the drying tower is low. The gas temperature is increased by the moving path of the continuous curved pipe in the transfer tower. When the gas enters the carbon dioxide heat pump dryer, there is no need to consume a small amount of heat energy in the carbon dioxide heat pump dryer, which achieves the effect of energy saving and emission reduction. If the gas passing through the drying tower is directly passed into the carbon dioxide heat pump dryer, the temperature in the carbon dioxide heat pump dryer will drop, and the carbon dioxide heat pump dryer needs to increase the operating power to ensure the normal drying efficiency of the lignite.

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