Evaporated moisture recycling system and method of rotary coal slime indirect drying machine

Abstract

The invention discloses an evaporation moisture recycling system and method of a rotary coal slime indirect drying machine, and belongs to the field of material drying. The evaporation moisture recycling system mainly comprises a condensation system, a water treatment system, a dust removal system, an air pump, a gas heating system and an inert gas automatic inflation system; the system can be combined with any drying machine which cannot be repeatedly utilized to evaporate moisture; the evaporated moisture recycling system provides dry hot carrier gas for the drying machine, the dry hot carrier gas heats and dries wet materials in the drying machine to form evaporated moisture, and the evaporated moisture discharged by the drying machine is returned to the evaporated moisture recycling system. And the evaporation moisture recycling system is used for dedusting, condensing and heating the evaporation moisture, so that the evaporation moisture is changed into dry hot carrier gas. According to the invention, the temperature and the inert gas in the evaporated moisture are recycled, the waste heat of the evaporated moisture and the inert gas in the evaporated moisture are fully recycled, the drying cost is greatly saved, and zero emission of the gas is realized.

Description

Technical Field

[0001] The present invention relates to a system and method for recycling evaporated moisture of a rotary coal slime indirect dryer, and belongs to the field of material drying. Background Art

[0002] Many coal products have a certain calorific value. However, due to their physical characteristics such as high moisture content, such as lignite and coal slime by-products produced by coal washing, most of them cannot be directly used for combustion power generation and must be dehydrated and dried, making the comprehensive utilization of resources difficult. The rotary coal slime indirect dryer based on steam indirect drying technology has no safety hazards such as coal slime coking, ignition, and dust explosion, and solves problems such as environmental pollution and operation safety, and has been widely used.

[0003] A dryer is a device that uses heat energy to reduce the moisture content of materials. By heating wet materials in the dryer, the moisture in them is vaporized and escapes, and the vaporized moisture is carried away by blowing in dry hot gas, so as to achieve the purpose of drying wet materials. In this process, the dry hot gas combines with the vaporized moisture to form evaporated moisture.

[0004] For example: CN218915693U discloses a rotary coal slime indirect dryer, including a cylinder that can rotate axially. The cylinder is provided with a drying chamber, an inlet and an outlet that communicate with both ends of the drying chamber. The height of the inlet is higher than the height of the outlet; a plurality of first lifters are connected to the inner wall of the cylinder at intervals, and filter screens are correspondingly arranged on the first lifters. The filter screens are connected to the cylinder, and the first lifters, the filter screens and the cylinder enclose a receiving chamber for receiving materials to be dried. CN107940937B discloses a coal slime indirect drying system, including a first conveyor, a mixer, a feeder, a dryer and a second conveyor. The output end of the first conveyor is connected to the first input end of the mixer. The output end of the mixer is connected to the input end of the dryer through the feeder. The output end of the dryer is connected to the input end of the second conveyor. The first output end of the second conveyor is connected to the second input end of the mixer, and the second output end is used to output the dried coal slime; the mixer is used to mix the coal slime provided by the first conveyor and the second conveyor, and convey the coal slime to the dryer through the feeder; the dryer can slowly turn the coal slime and indirectly heat and dry the coal slime by using steam.

[0005] The above dryers all have the problem that the evaporated moisture cannot be recycled. There is still a certain amount of waste heat in the evaporated moisture, and in order to prevent coal slime coking and ignition, a large amount of inert gas is added to the dry hot gas and the evaporated moisture. When the evaporated moisture cannot be recycled, a large amount of inert gas is also wasted. Summary of the Invention

[0006] The present invention mainly aims at the problem that the evaporated moisture discharged from the current rotary slime indirect dryer cannot be reused, and proposes a system and method for reusing the evaporated moisture of a rotary slime indirect dryer.

[0007] The evaporated moisture reuse system mainly includes: a condensation system 1, a water treatment system 2, a dust removal system 3, an air pump 4, a gas heating system 5, and an inert gas automatic inflation system 6. The evaporated moisture reuse system is a system that can be combined with a dryer 12, aiming to realize the reuse of the waste heat and inert gas in the evaporated moisture, and achieve the purpose of energy conservation, environmental protection, and ultra-clean emission.

[0008] An evaporated moisture reuse system for a rotary slime indirect dryer can be combined with any rotary slime indirect dryer that cannot reuse the evaporated moisture. The combination method is as follows: The evaporated moisture reuse system provides dry heating gas for the dryer. The dry heating gas heats and dries the wet material in the dryer to form evaporated moisture. The evaporated moisture discharged from the dryer will return to the evaporated moisture reuse system. After the system removes dust, condenses, and heats the evaporated moisture, the evaporated moisture is changed back into dry heating gas.

[0009] The dryer 12 has a wet material inlet 10, an evaporated moisture outlet 11, heating pipes 13 inside the dryer, a material flow channel 14 inside the dryer, a hot dry air inlet 15 of the dryer, and a dry material outlet 16 of the dryer.

[0010] The evaporated moisture outlet 11 of the dryer is connected to the dust removal system 3. The dust removal system 3 is connected to the condensation system 1. The condensation system 1 has an exhaust port and a condensate outlet. The exhaust port of the condensation system is connected to the air pump 4. The condensate outlet of the condensation system is connected to the water treatment system 2. The air pump 4 is connected to the gas heating system 5. The gas heating system 5 is connected to the hot dry air inlet 15 of the dryer.

[0011] An evaporated moisture reuse method for a rotary slime indirect dryer mainly includes the following steps:

[0012] (1) The dry heating gas enters the dryer 12 through the hot dry air inlet 15 of the dryer, heats the wet material in the material flow channel 14 inside the dryer, and takes away the moisture vaporized from the wet material. In this process, the heating gas combines with the moisture vaporized from the wet material to form evaporated moisture.

[0013] (2) The evaporated moisture generated in step (1) is discharged from the dryer 12 and enters the dust removal system 3. The dust removal system 3 removes the dust carried in the evaporated moisture.

[0014] (3) The evaporated moisture dust-removed by the dust removal system 3 in step (2) enters the condensation system 1. The condensation system 1 condenses and dries the evaporated moisture to generate dry condensed gas and dust-containing wastewater.

[0015] (4) The dust-containing wastewater generated in step (3) enters the water treatment system 2 and is discharged after treatment.

[0016] (5) The air pump 4 pumps the dry condensed gas generated in step (3) into the heating system 5. The heating system 5 is equipped with an inert gas detector. When the content of inert gas is lower than the threshold value, the inert gas is supplemented through the inert gas automatic inflation system 6. The dry condensed gas after supplementing inert gas and heating becomes dry hot carrier gas.

[0017] (6) The dry hot carrier gas generated in step (5) will enter the dryer 12 again to dry the wet material.

[0018] Preferably, in any of the above solutions, the gas heating system is equipped with a temperature sensor, which can accurately control the temperature of the dry hot carrier gas between 200°C and 450°C.

[0019] Preferably, in any of the above solutions, the pumping pressure of the air pump 4 will be automatically controlled according to the moisture content of the wet material, and the pressure range is between 0.5 Mpa and 0.8 Mpa.

[0020] Preferably, in any of the above solutions, the temperature of the evaporated moisture is between 105°C and 200°C, and the temperature of the dry condensed gas is between 50°C and 90°C.

[0021] Preferably, in any of the above solutions, the gas heating system is equipped with an inert gas content detector, and the inert gas automatic inflation system automatically detects the inert gas content in the gas heating system. When the inert gas content is lower than 98%, inert gas is automatically supplemented into the heater to make the inert gas content greater than 98%.

[0022] Preferably, in any of the above solutions, the inert gas supplemented by the inert gas automatic inflation system is nitrogen.

[0023] Preferably, in any of the above solutions, the dryer is a rotary slime indirect dryer. The inside of the dryer is a wet material flow channel, and multiple heating pipes are arranged in parallel. The hot carrier gas directly contacts the wet material in the dryer, and the wet material in the dryer is heated by the heating pipes and the hot carrier gas at the same time. At the same time, the hot carrier gas can take away the moisture in the wet material. In this process, the hot carrier gas combines with the moisture to form evaporated moisture.

[0024] Preferably, in any of the above solutions, the dust collector is a multi-tube cyclone dust collector.

[0025] Preferably, in any of the above solutions, the diameter of the cyclone of the multi-tube cyclone dust collector is between 120 and 200 mm, which can effectively capture dust with a particle size of 4 to 15 μm, can handle the evaporated moisture with a relatively high dust concentration, has good dust removal effect, can meet the national emission standards, and is safe and reliable.

[0026] Preferably, in any of the above solutions, the wet material is granular, such as lignite and long-flame coal with a particle size less than 30 mm.

[0027] In the present invention, the evaporated moisture recycling system of the rotary coal slime indirect dryer is to sequentially pass the evaporated moisture discharged from the dryer through dust removal, condensation, and heating to become dry hot carrier gas, and then the dry hot carrier gas enters the dryer and combines with the moisture gasified from the wet material to form evaporated moisture again, and so on in a cycle.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) In the present invention, the temperature and inert gas in the evaporated moisture are recycled, fully recovering and utilizing the waste heat of the evaporated moisture and the inert gas therein, greatly saving the drying cost.

[0030] (2) Realize zero gas emission, not only saving the cost of emission treatment, but also being green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a system device connection diagram of the evaporated moisture recycling of the rotary coal slime indirect dryer according to a preferred embodiment of the present invention.

[0032] In the figure:

[0033] 1 is the condensation system, 2 is the water treatment system

[0034] 3 is the dust removal system, 4 is the air pump

[0035] 5 is the gas heating system, 6 is the inert gas automatic inflation system

[0036] 7 is the saturated steam outlet of the dryer, 8 is the saturated steam inlet of the dryer

[0037] 9 is the power plant boiler, 10 is the wet material inlet

[0038] 11 is the evaporated moisture outlet of the dryer, 12 is the dryer

[0039] 13 is the heating pipeline in the dryer, 14 is the material flow channel in the dryer

[0040] 15 is the hot dry air inlet of the dryer, 16 is the dry material outlet of the dryer DETAILED DESCRIPTION OF THE INVENTION

[0041] To further understand the technical features of the present invention, the present invention will be described in detail below in conjunction with specific embodiments. The embodiments only have an exemplary effect on the present invention and do not have any restrictive effect. Any non-substantive modifications made by those skilled in the art based on the present invention shall fall within the protection scope of the present invention.

[0042] Embodiment 1:

[0043] The evaporation moisture reuse system of the rotary type coal slime indirect dryer in the preferred embodiment of the present invention, as Figure 1 shown, is composed of a condensation system 1, a water treatment system 2, a dust removal system 3, an air pump 4, a gas heating system 5, and an inert gas automatic inflation system 6.

[0044] The wet material is granular lignite with a moisture content of 40%. The wet material enters the dryer 12 through the wet material inlet 10. Under the action of gravity, the wet material flows downward in the material flow channel 14 in the dryer. After the wet material is heated and dried in the dryer, it is discharged from the dry material outlet 16 of the dryer. The moisture content of the wet material will be detected in real time by the moisture content sensor in the dryer after entering the dryer.

[0045] When the wet material flows in the channel 14, it is simultaneously heated by the heating pipe 13 and the hot carrier gas. The moisture in the wet material is vaporized after heating, and the vaporized moisture is carried away by the hot carrier gas.

[0046] The hot carrier gas enters the material flow channel 14 in the dryer from the hot dry air inlet 15 of the dryer. The flow direction of the hot carrier gas is from bottom to top, opposite to the material flow direction. While heating the wet material, the hot carrier gas carries away the moisture vaporized from the wet material. The hot carrier gas combines with the vaporized moisture to form evaporation moisture, which is discharged from the evaporation moisture outlet 11 of the dryer.

[0047] The evaporation moisture enters the dust removal system 3, and the dust removal system 3 removes the dust carried in the evaporation moisture. The evaporation moisture after being dust-removed by the dust removal system will enter the condensation system 1. The condensation system 1 reduces the temperature of the evaporation moisture to between 50°C and 90°C, condenses and dries the moisture in the evaporation moisture, generating dry condensate gas and dust-containing wastewater.

[0048] The dust-containing wastewater enters the water treatment system 2 and is discharged after treatment. The air pump 4 pumps the dry condensate gas discharged from the generated condensation system 1 into the heating system 5. The pumping pressure of the air pump 4 will be automatically controlled according to the moisture content of the wet material, and the pressure range is between 0.5 MPa and 0.8 MPa. When the moisture content of the wet material is 40%, the pumping pressure is 0.6 MPa.

[0049] The heating system 5 is equipped with an inert gas detector. When the content of inert gas is lower than 98%, inert gas is supplemented through the inert gas automatic inflation system 6 to make the inert gas content greater than 98%. The heating system heats the dried and condensed gas after supplementing inert gas to a temperature between 200°C and 450°C. The dried and condensed gas after supplementing inert gas and heating becomes a dried hot carrier gas.

[0050] The dried hot carrier gas will enter the dryer 12 again to dry the wet material. This process repeats in a cycle.

[0051] The parts not described in the present invention belong to the well-known technologies of those skilled in the art.

[0052] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, within the scope of the technical solution of the present invention, can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content. However, as long as it does not depart from the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An evaporation moisture recycling system of a rotary coal slime indirect dryer, characterized in that: The dryer 12 comprises a condensation system 1, a water treatment system 2, a dust removal system 3, an air pump 4, a gas heating system 5, and an inert gas automatic filling system 6. The dryer 12 has a wet material inlet 10, an evaporative moisture outlet 11, a heating pipe 13 in the dryer, a material flow channel 14 in the dryer, a hot dry air inlet 15 of the dryer, and a dry material outlet 16 of the dryer. The evaporative moisture outlet 11 of the dryer is connected to the dust removal system 3, the dust removal system 3 is connected to the condensation system 1, the condensation system 1 has an exhaust port and a condensed water outlet, the exhaust port of the condensation system is connected to the air pump 4, the condensed water outlet of the condensation system is connected to the water treatment system 2, the air pump 4 is connected to the gas heating system 5, and the gas heating system 5 is connected to the hot dry air inlet 15 of the dryer.

2. A method for recycling the evaporation moisture recycling system of the rotary coal slime indirect dryer according to claim 1, characterized in that: The main steps include: (1) Drying The hot carrier gas enters the dryer 12 through the hot dry air inlet 15 of the dryer, heats the wet material in the material flow channel 14 in the dryer, and takes away the moisture vaporized from the wet material. In this process, the hot carrier gas combines with the moisture vaporized from the wet material to form evaporated moisture. (2) The evaporated moisture generated in step (1) is discharged from the dryer 12 and enters the dust removal system 3. The dust removal system 3 removes the dust carried by the evaporated moisture. (3) The evaporated moisture that has been dedusted by the dust removal system 3 in step (2) enters the condensation system 1. The condensation system 1 condenses and dries the evaporated moisture to generate dry condensed gas and dust-containing wastewater. (4) The dust-containing wastewater generated in step (3) enters the water treatment system 2 and is discharged after treatment. (5) The air pump 4 pumps the dry condensed gas generated in step (3) into the heating system 5. The heating system 5 has an inert gas detector. When the inert gas content is lower than the threshold value, the inert gas is replenished through the inert gas automatic filling system 6. (6) The dry condensed gas, which has been supplemented with inert gas and heated in step (5), will enter the dryer 12 again to dry the wet material.

3. According to the method for recycling evaporated moisture of a rotary coal slime indirect dryer as described in claim 2, the gas heating system is provided with a temperature sensor, which can accurately control the temperature of the dry hot carrier gas between 200°C and 450°C.

4. According to the method for recycling evaporated moisture of a rotary coal slime indirect dryer as described in claim 2, the pumping pressure of the air pump 4 will be automatically controlled according to the moisture content of the wet material, and the pressure range is between 0.5MPa and 0.8MPa.

5. The method for recycling evaporated moisture of a rotary coal slime indirect dryer according to claim 2, wherein the temperature of the evaporated moisture is between 105°C and 200°C, and the temperature of the dry condensed gas is between 50°C and 90°C.

6. According to the method for recycling evaporated moisture of a rotary coal slime indirect dryer as described in claim 2, an inert gas content detector is installed in the gas heating system 5, and the inert gas automatic filling system 6 automatically detects the inert gas content in the gas heating system 5. When the inert gas content is lower than 98%, the inert gas is automatically supplemented into the heater to make the inert gas content greater than 98%.

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