Device and method for increasing temperature of outlet of coal mill through steam extraction of steam turbine

Abstract

The invention relates to the technical field of increasing the air outlet temperature of a coal mill, in particular to a device for increasing the temperature of an outlet of the coal mill by utilizing steam extraction of a steam turbine, which comprises a bottom plate, and a boiler, a water inlet mechanism and a fuel feeding mechanism which are arranged on the bottom plate, the two inlet steam isolation valves on the lower connecting pipe are used for adjusting the air inflow of high-temperature steam, the two coal mills work to grind coal blocks into coal powder, the coal powder passing through the interior of the powder pipe of the heat exchanger is heated by the high-temperature steam, the temperature of primary air entering the boiler is increased, the combustion stability in the boiler and the burnout performance of the coal powder are improved, and the energy consumption of the boiler is reduced. In addition, the air quantity entering the coal mill is reduced, the ventilation resistance of the coal mill is reduced, the auxiliary power consumption rate is reduced, and the economical efficiency of the unit is improved; high-temperature steam passing through a spiral flow deflector is changed into low-temperature steam after absorbing heat and being exhausted, the low-temperature steam enters a fifth low-pressure heater to preheat cold water, and the preheated water is fed into a boiler; and the water heating speed of the boiler is increased.

Description

Technical Field

[0001] The invention relates to the technical field of increasing the outlet air temperature of a coal mill, and in particular to a device and method for increasing the outlet temperature of a coal mill by utilizing steam extraction from a steam turbine. Background Art

[0002] Boiler coal mill is a machine that grinds coal into coal powder, and is an important auxiliary equipment for coal-fired boilers. Coal mills are mechanical equipment, and are generally divided into three types according to the speed: low-speed coal mills, medium-speed coal mills, and high-speed coal mills. In the boiler unit of the direct-blowing pulverizing system, the coal mill and the pulverizing system have formed a closely related whole with the boiler itself. Primary air refers to the air sent from the bottom of the grate when the layer-fired furnace is burning; the air sent into the furnace together with the pulverized coal when the pulverized coal is burning; the air sent into the furnace from the root of the fire when the oil and gas fuels are burning.

[0003] However, the current boiler coal mill grinds coal blocks when working, and the ground coal powder directly enters the interior of the furnace and is burned through the burner. The coal powder and primary air before combustion are not heated, the combustion stability and coal powder burnout in the boiler cannot be improved, the exhaust gas temperature cannot be reduced, and the boiler efficiency cannot be improved; the plant power consumption rate cannot be reduced, and the unit economy cannot be improved; the boiler exhaust chimney still has a high temperature, the heat here cannot be utilized, resulting in heat waste and the power of other units cannot be reduced; and the smoke inside the chimney is difficult to clean, which can easily cause the chimney to be blocked, and the slow exhaust of flue gas affects the combustion of fuel. Summary of the invention

[0004] In view of the problems in the prior art, the present invention provides a device and method for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a device for increasing the outlet temperature of a coal mill by extracting steam from a steam turbine, comprising a bottom plate, a boiler, a water inlet mechanism and a fuel feeding mechanism installed on the bottom plate, wherein the fuel feeding mechanism is connected to the boiler, the water inlet mechanism is connected to the boiler, a preheating mechanism is installed on the fuel feeding mechanism, and the preheating mechanism is connected to the water inlet mechanism; the fuel feeding mechanism comprises two coal mills, and the air outlet positions of the two coal mills are both equipped with four powder pipes in a circular array; the preheating mechanism comprises eight heat exchangers, and the outer walls of the four powder pipes on the two coal mills are both equipped with heat exchangers, and spiral guide vanes are installed between the outer walls of the eight powder pipes and the heat exchangers, and the bottoms of the four heat exchangers on the same side are all connected to high-temperature steam inlet pipes, and the four high-temperature steam inlets on the same side are connected to the high-temperature steam inlets. A bottom ring is connected to the bottom of the inlet pipe, a lower connecting pipe is connected between the two bottom rings, a suction pipe is connected to the lower connecting pipe, two inlet steam isolation valves are installed on the lower connecting pipe, the tops of the four heat exchangers on the same side are connected to the low-temperature steam outlet pipe, the four low-temperature steam outlet pipes on the same side are connected to the top ring, an upper connecting pipe is connected between the two top rings, a discharge pipe is connected to the upper connecting pipe, two outlet steam isolation valves are installed on the upper connecting pipe, and regulating valves are installed on the eight high-temperature steam inlet pipes and the eight low-temperature steam outlet pipes; the water inlet mechanism includes a No. 5 low-pressure heater and a high-pressure heater, a No. 5 low-pressure heater, a high-pressure heater and a water inlet pipe are installed on the bottom plate, one end of the discharge pipe is connected to the No. 5 low-pressure heater, and a water inlet pipe is connected between the high-pressure heater and the boiler.

[0006] Specifically, the extraction pipe is located at the center of the lower connecting pipe, and the two inlet steam isolation valves are symmetrically arranged about the extraction pipe.

[0007] Specifically, the row pipe is located at the center of the upper connecting pipe, and the two outlet steam isolation valves are symmetrically arranged about the row pipe.

[0008] Specifically, the fuel feeding mechanism also includes a collecting box, the eight powder pipes are connected to the collecting box, the side wall of the collecting box is connected to a fuel delivery pipe, a burner is installed at one end of the boiler, and the end of the fuel delivery pipe is connected to the burner.

[0009] Specifically, the water inlet mechanism also includes a water pump and a left low-pressure heater. A left low-pressure heater connected to the No. 5 low-pressure heater is installed on the bottom plate. A deaerator is installed on the bottom plate. The No. 5 low-pressure heater is connected to the deaerator, and the deaerator is connected to the high-pressure heater.

[0010] Specifically, a smoke exhaust mechanism is installed on the boiler, and the smoke exhaust mechanism includes a smoke bin. A smoke bin is installed at the other end of the boiler, and a chimney is connected to the smoke bin.

[0011] Specifically, the smoke exhaust mechanism also includes a heat absorption pipe, the outer wall of the chimney is spirally wound with the heat absorption pipe, one end of the heat absorption pipe is installed with a water inlet valve, the hollow heat absorption pipe inside is installed with a sewage pipe, the sewage pipe is installed with a sewage valve, the heat absorption pipe is connected to a reflux pipe with an inverted L-shaped structure, and the reflux pipe is installed with a liquid level display.

[0012] Specifically, a cleaning mechanism is installed inside the chimney, and the cleaning mechanism includes four slide grooves. Four slide grooves are axially opened in a circular array on the inner wall of the chimney. The insides of the four slide grooves are slidably connected with scrapers of an annular structure, and a fixing frame is installed on the scraper.

[0013] Specifically, the cleaning mechanism further comprises a taking port, a taking port is provided at the center of the fixing frame, the fixing frame is in a cross-shaped structure, and a plurality of holes are provided on the scraper.

[0014] An operating method of a device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine comprises the following steps:

[0015] S1: First, connect the high-temperature steam of the steam turbine to the extraction pipe, and use the inlet steam isolation valve to allow the high-temperature steam to enter the two sets of high-temperature steam inlet pipes, and then pass through the heat exchanger to add the coal blocks into the two coal mills. At this time, the coal powder crushed by the two coal mills enters the two sets of powder pipes, and the coal powder passes through the powder pipes inside the heat exchanger and is heated by the high-temperature steam.

[0016] S2: Then, the pulverized coal heated by the high-temperature steam enters the interior of the collecting box, and is finally discharged from the fuel delivery pipe to the interior of the burner for combustion to heat the boiler. The high-temperature steam heats the pulverized coal and the low-temperature primary air inside the pulverized coal pipe to become high-temperature primary air, thereby increasing the temperature of the pulverized coal. At this time, the steam discharged from the heat exchanger passes through the spiral guide vane and becomes low-temperature steam. The low-temperature steam is discharged from the low-temperature steam outlet pipe at the top of the heat exchanger, and the low-temperature steam enters the interior of the No. 5 low-pressure heater again;

[0017] S3: Then, the water pump heats the cold water through the left low-pressure heater, the fifth low-pressure heater, the deaerator, and the high-pressure heater in sequence to convert it into high-temperature water, and sends it to the boiler;

[0018] S4: Finally, the smoke from the combustion of the boiler is discharged from the smoke exhaust mechanism, the outer shell of the chimney can absorb heat, and cold water enters from the bottom of the heat absorption tube. Observe the liquid level display, and the water should not exceed half of the vertical position of the return pipe. Then, the steam in the cavity of the return pipe can be input into the interior of the steam turbine. When the smoke on the inner wall of the chimney needs to be cleaned, the fixed frame is pulled by a tool with a hook to realize the movement of the scraper on the inner wall of the chimney to clean the smoke.

[0019] The beneficial effects of the present invention are:

[0020] (1) The device for increasing the outlet temperature of a coal mill by extracting steam from a steam turbine described in the present invention can connect an extraction pipe to a steam turbine, and high-temperature steam is discharged from the steam turbine. The intake amount of the high-temperature steam is adjusted by two inlet steam isolation valves on the lower connecting pipe, and the regulating valves on the two sets of high-temperature steam inlet pipes are opened to allow the high-temperature steam to enter the interior of the heat exchanger. At this time, the two coal mills work to grind the coal blocks into coal powder. The coal powder in the powder pipe of the heat exchanger is heated by the high-temperature steam, thereby increasing the temperature of the coal powder and the primary air. After the coal powder and the primary air entering the furnace are heated, the temperature of the primary air entering the boiler is increased, the combustion stability and the coal powder burnout in the boiler are improved, and the exhaust gas temperature is reduced, thereby increasing the boiler efficiency. On the other hand, the air volume entering the coal mill is reduced, the ventilation resistance of the coal mill is reduced, the plant power consumption rate is reduced, and the unit economy is improved. The high-temperature steam passing through the spiral guide vane is discharged after absorbing heat and becomes low-temperature steam. The low-temperature steam enters the interior of the No. 5 low-pressure heater to be preheated with cold water, and the preheated water is then sent to the boiler, thereby increasing the heating speed of the boiler for water.

[0021] (2) The device described in the present invention utilizes steam extraction from a steam turbine to increase the outlet temperature of a coal mill. When the boiler is working, the amount of cold water entering the heat absorption pipe can be controlled by opening the water inlet valve. The cold water should not exceed half of the vertical position of the return pipe. The water volume can be observed through a liquid level display. The spiral structure of the heat absorption pipe can absorb and utilize the heat of the chimney. When the heat absorption pipe heats the water, the water will generate steam. The return pipe can be connected to the steam turbine to heat the steam inside the steam turbine, which is beneficial for the steam turbine to quickly generate high-temperature steam. When too much water is added to the return pipe, the drain pipe can be opened to drain the water.

[0022] (3) The device described in the present invention utilizes steam extraction from a steam turbine to increase the outlet temperature of a coal mill. A cleaning mechanism is installed inside the chimney. When there is a lot of smoke and dust inside the chimney, the pipe at the end of the chimney can be disconnected. The fixed frame can be pulled by a hook tool to enable the scraper to rise inside the slide. During the process of the scraper rising, the chimney inside the chimney is cleaned to avoid the inability to discharge smoke inside the furnace and increase the temperature of the chimney. The burnout of the fuel can also be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0024] Figure 1 The overall structural schematic diagram of a preferred embodiment of a device and method for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine provided by the present invention;

[0025] Figure 2It is an enlarged schematic diagram of the connection structure of the powder pipe, coal mill and heat exchanger of the present invention;

[0026] Figure 3 It is a schematic diagram of the connection structure of the upper connecting pipe, the top ring and the low-temperature steam outlet pipe of the present invention;

[0027] Figure 4 It is a schematic diagram of the connection structure of the powder tube, the spiral guide vane and the heat exchanger of the present invention;

[0028] Figure 5 It is a schematic diagram of the connection structure of the heat exchanger, the high-temperature steam inlet pipe and the low-pressure steam outlet pipe of the present invention;

[0029] Figure 6 It is a schematic diagram of the connection structure of the chimney, the heat absorption pipe and the return pipe of the present invention;

[0030] Figure 7 It is a schematic diagram of the chimney, the heat absorbing tube and the scraper of the present invention;

[0031] Figure 8 It is a schematic diagram of the connection structure of the heat absorption pipe, the reflux pipe and the liquid level display of the present invention;

[0032] Fig. 9 It is a schematic diagram of the connection structure of the scraper and the fixing frame of the present invention.

[0033] In the figure: 1, bottom plate; 2, boiler; 3, water inlet mechanism; 301, water pump; 302, left low-pressure heater; 303, No. 5 low-pressure heater; 304, deaerator; 305, high-pressure heater; 306, water inlet pipe; 4, fuel feeding mechanism; 401, coal mill; 402, powder pipe; 403, collecting box; 404, fuel delivery pipe; 405, burner; 5, preheating mechanism; 501, heat exchanger; 502, high-temperature steam inlet pipe; 503, bottom ring; 504, lower connecting pipe; 505, extraction pipe; 506, Low-temperature steam outlet pipe; 507, top ring; 508, discharge pipe; 509, upper connecting pipe; 510, inlet steam isolation valve; 511, outlet steam isolation valve; 512, regulating valve; 513, spiral guide vane; 6, smoke exhaust mechanism; 601, smoke bin; 602, chimney; 603, heat absorption pipe; 604, reflux pipe; 605, liquid level indicator; 606, sewage pipe; 607, water inlet valve; 608, sewage valve; 7, cleaning mechanism; 701, slide; 702, scraper; 703, fixing frame; 704, taking port. DETAILED DESCRIPTION

[0034] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0035] like Figure 1-Figure 9As shown, the device and method for increasing the outlet temperature of a coal mill by using steam turbine extraction of the present invention comprises a bottom plate 1, a boiler 2, a water inlet mechanism 3 and a fuel feeding mechanism 4 installed on the bottom plate 1, wherein the fuel feeding mechanism 4 is connected to the boiler 2, the water inlet mechanism 3 is connected to the boiler 2, a preheating mechanism 5 is installed on the fuel feeding mechanism 4, and the preheating mechanism 5 is connected to the water inlet mechanism 3; the fuel feeding mechanism 4 comprises two coal mills 401, and the air outlet positions of the two coal mills 401 are both equipped with four powder pipes 402 in a circular array; the preheating mechanism 5 comprises eight heat exchangers 501, and the outer walls of the four powder pipes 402 on the two coal mills 401 are both equipped with heat exchangers 501, and the outer walls of the eight powder pipes 402 are connected to the heat exchangers 501. Spiral guide plates 513 are installed between the heat exchangers 501 on the same side, the bottoms of the four heat exchangers 501 on the same side are connected to high-temperature steam inlet pipes 502, the bottoms of the four high-temperature steam inlet pipes 502 on the same side are connected to bottom rings 503, a lower connecting pipe 504 is connected between two bottom rings 503, a suction pipe 505 is connected to the lower connecting pipe 504, two inlet steam isolation valves 510 are installed on the lower connecting pipe 504, the tops of the four heat exchangers 501 on the same side are connected to low-temperature steam outlet pipes 506, the four low-temperature steam outlet pipes 506 on the same side are connected to top rings 507, an upper connecting pipe 509 is connected between two top rings 507, a discharge pipe 508 is connected to the upper connecting pipe 509, the Two outlet steam isolation valves 511 are installed on the upper connecting pipe 509, and regulating valves 512 are installed on the eight high-temperature steam inlet pipes 502 and the eight low-temperature steam outlet pipes 506; the water inlet mechanism 3 includes a No. 5 low-pressure heater 303 and a high-pressure heater 305, and the No. 5 low-pressure heater 303, the high-pressure heater 305 and the water inlet pipe 306 are installed on the bottom plate 1, one end of the drain pipe 508 is connected to the No. 5 low-pressure heater 303, and the water inlet pipe 306 is connected between the high-pressure heater 305 and the boiler 2; the extraction pipe 505 is located at the center of the lower connecting pipe 504, and the two inlet steam isolation valves 510 are symmetrically arranged about the extraction pipe 505; the drain pipe 508 is located at the center of the upper connecting pipe 509, and the two The outlet steam isolation valve 511 is symmetrically arranged about the drain pipe 508; the fuel feeding mechanism 4 also includes a collecting box 403, the eight powder pipes 402 are connected with the collecting box 403, the side wall of the collecting box 403 is connected with a fuel delivery pipe 404, a burner 405 is installed at one end of the boiler 2, and the end of the fuel delivery pipe 404 is connected to the burner 405; the water inlet mechanism 3 also includes a water pump 301 and a left low-pressure heater 302, a left low-pressure heater 302 connected to the No. 5 low-pressure heater 303 is installed on the bottom plate 1, a deaerator 304 is installed on the bottom plate 1, the No. 5 low-pressure heater 303 is connected to the deaerator 304, and the deaerator 304 is connected to the high-pressure heater 305;The extraction pipe 505 is connected to the steam exhaust pipe of the steam turbine. At this time, the high-temperature steam enters the interior of the extraction pipe 505, and then enters the interior of the lower connecting pipe 504. The intake speed and intake flow rate of the high-temperature steam are adjusted by two inlet steam isolation valves 510. The two coal mills 401 are started, and coal blocks are added to the interior of the two coal mills 401 through the feeding pipes. The coal blocks are crushed into coal powder, and the coal powder is blown to the interior of the two groups of powder pipes 402 by the coal mill 401. The regulating valves 512 on the two groups of high-temperature steam inlet pipes 502 are opened, and the high-temperature steam in the lower connecting pipe 504 will enter the interior of the high-temperature steam inlet pipe 502 from the two bottom rings 503, and then the high-temperature steam passes through the interior of the heat exchanger 501. The high-temperature steam will pass through the track formed by the spiral guide vanes 513 in the heat exchanger 501, and finally discharged from the low-temperature steam outlet pipe 506. The high-temperature steam passing through the heat exchanger 501 will be absorbed by the powder pipe 402, so the coal powder and primary air in the powder pipe 402 are heated. Heat, low-temperature primary air and high-temperature steam counter-circulate heat in the heat exchanger 501. After the pulverized coal is heated, it passes through the inside of the collecting box 403 and finally flows from the fuel delivery pipe 404 to the inside of the furnace and is burned by the burner 405, which increases the temperature of the primary air entering the boiler 2, improves the combustion stability and pulverized coal burnout in the boiler 2, and reduces the exhaust gas temperature, thereby improving the efficiency of the boiler 2. On the other hand, it reduces the air volume entering the coal mill 401, reduces the ventilation resistance of the coal mill 401, reduces the plant power consumption rate, and improves the unit economy. The low-temperature steam is discharged from the two sets of low-temperature steam outlet pipes 506 and merges from the upper connecting pipe 509, and finally discharged from the discharge pipe 508 to the inside of the No. 5 low-pressure heater 303 to heat the water. The water will be pumped into the inside of the left low-pressure heater 302 and the inside of the No. 5 low-pressure heater 303 by the water pump 301, and is heated by the high-pressure heater 305 after passing through the deaerator 304. Finally, the heated water is transported to the inside of the boiler 2 by the water inlet pipe 306 to achieve the effect of preheating. ;

[0036] Specifically, Figure 6 , Figure 7 and Figure 8As shown, the boiler 2 is equipped with a smoke exhaust mechanism 6, which includes a smoke bin 601. The other end of the boiler 2 is equipped with a smoke bin 601, and the smoke bin 601 is connected to a chimney 602; the smoke exhaust mechanism 6 also includes a heat absorbing pipe 603, the outer wall of the chimney 602 is spirally wound with the heat absorbing pipe 603, one end of the heat absorbing pipe 603 is equipped with a water inlet valve 607, the hollow heat absorbing pipe 603 is equipped with a sewage pipe 606, the sewage pipe 606 is equipped with a sewage valve 608, the heat absorbing pipe 603 is connected with a return pipe 604 with an inverted L-shaped structure, and the return pipe 604 is equipped with a liquid level display 605; when the boiler 2 is in use, the water inlet valve 607 on the heat absorbing pipe 603 is opened to allow cold water to enter the interior of the heat absorbing pipe 603. Since the heat absorbing pipe 603 is spirally attached to the outer wall of the chimney 602, a large amount of heat will be generated when the chimney 602 exhausts smoke. After absorbing heat, the heat absorption tube 603 heats the water inside it, and the water volume cannot exceed half of the vertical position of the return pipe 604 to prevent the water from being transported to the inside of the steam turbine. The heated water will produce steam, and the hot steam will be connected to the steam turbine through the return pipe 604 to preheat the steam inside the steam turbine, increase the temperature of the water vapor, shorten the heating time, and the internal water volume of the heat absorption tube 603 can be controlled by the drain valve 608. When the water volume is too much, the drain valve 608 can be opened to drain the water.

[0037] Specifically, Figure 7 and Fig. 9 As shown, a cleaning mechanism 7 is installed inside the chimney 602, and the cleaning mechanism 7 includes four slide grooves 701. Four slide grooves 701 are axially opened in a circular array on the inner wall of the chimney 602. A scraper 702 of an annular structure is slidably connected inside the four slide grooves 701. A fixing frame 703 is installed on the scraper 702; the cleaning mechanism 7 also includes a taking port 704. The center of the fixing frame 703 is provided with a taking port 704. The fixing frame 703 is cross-shaped. The scraper 702 is provided with a plurality of holes; when the smoke inside the chimney 602 needs to be cleaned, the pipe on the chimney 602 is disassembled, the holes on the fixing frame 703 are hooked by a hook tool, and the scraper 702 is pulled, so that the scraper 702 can be lifted and lowered inside the slide 701. When the scraper 702 is lifted and lowered, the smoke on the inner wall of the chimney 602 can be cleaned, so that the chimney 602 is prevented from being blocked, the temperature of the outer wall of the chimney 602 is prevented from being too high, and the coal powder inside the furnace is fully burned.

[0038] An operating method of a device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine comprises the following steps:

[0039] S1: First, connect the high-temperature steam of the steam turbine to the extraction pipe 505, and use the inlet steam isolation valve 510 to allow the high-temperature steam to enter the two sets of high-temperature steam inlet pipes 502, and then pass through the heat exchanger 501 to add the coal blocks into the two coal mills 401. At this time, the coal powder after the two coal mills 401 are crushed enters the two sets of powder pipes 402, and the coal powder is heated by the high-temperature steam after passing through the powder pipes 402 inside the heat exchanger 501;

[0040] S2: Then, the pulverized coal heated by the high-temperature steam enters the interior of the collecting box 403, and is finally discharged from the fuel delivery pipe 404 to the interior of the burner 405 for combustion to heat the boiler 2. The high-temperature steam heats the pulverized coal and the low-temperature primary air inside the pulverized coal pipe 402 to become high-temperature primary air, thereby increasing the temperature of the pulverized coal. At this time, the steam discharged from the heat exchanger 501 passes through the spiral guide vane 513 and becomes low-temperature steam. The low-temperature steam is discharged from the low-temperature steam outlet pipe 506 at the top of the heat exchanger 501, and the low-temperature steam enters the interior of the No. 5 low-pressure heater 302 again.

[0041] S3: Then, the water pump 301 heats the cold water through the left low-pressure heater 302, the fifth low-pressure heater 303, the deaerator 304, and the high-pressure heater 305 in sequence to turn the cold water into high-temperature water, and sends it to the boiler 2;

[0042] S4: Finally, the smoke from the combustion of the boiler 2 is discharged from the smoke exhaust mechanism 6, and the shell of the chimney 602 can absorb heat. Cold water is introduced from the bottom of the heat absorption tube 603, and the liquid level display 605 is observed. The water should not exceed half of the vertical position of the return pipe 604. Then, the steam in the cavity position of the return pipe 604 can be input into the interior of the steam turbine. When the smoke dust on the inner wall of the chimney 602 needs to be cleaned, the fixed frame 703 is pulled by a tool with a hook to realize the movement of the scraper 702 on the inner wall of the chimney 602 to clean the smoke dust.

[0043] When the present invention is used, first, the extraction pipe 505 is connected to the steam exhaust pipe of the steam turbine, and then the high-temperature steam enters the extraction pipe 505, and then enters the lower connecting pipe 504. The intake speed and intake flow rate of the high-temperature steam are adjusted through two inlet steam isolation valves 510, and the two coal mills 401 are started. Coal blocks are added to the inside of the two coal mills 401 through the feeding pipes. The coal blocks are crushed into coal powder, and the coal powder is blown by the coal mill 401 to the inside of the two sets of powder pipes 402, and the two When the regulating valve 512 on the high-temperature steam inlet pipe 502 is opened, the high-temperature steam in the lower connecting pipe 504 will enter the high-temperature steam inlet pipe 502 from the two bottom rings 503, and then the high-temperature steam will pass through the inside of the heat exchanger 501, and the high-temperature steam will pass through the track formed by the spiral guide plate 513 inside the heat exchanger 501, and finally be discharged from the low-temperature steam outlet pipe 506. The high-temperature steam passing through the heat exchanger 501 will be absorbed by the powder pipe 402, so the coal powder and the powder pipe 402 will be heated. The primary air is heated, and the low-temperature primary air and high-temperature steam are counter-circulated in the heat exchanger 501. After the pulverized coal is heated, it passes through the inside of the collecting box 403 and finally flows from the fuel delivery pipe 404 to the inside of the furnace and is burned by the burner 405, thereby increasing the temperature of the primary air entering the boiler 2, improving the combustion stability and the burnout of the pulverized coal in the boiler 2, and reducing the exhaust gas temperature, thereby improving the efficiency of the boiler 2. On the other hand, the air volume entering the coal mill 401 is reduced, the ventilation resistance of the coal mill 401 is reduced, the plant power consumption rate is reduced, and the unit economy is improved. The low-temperature steam is discharged from the two groups of low-temperature steam outlet pipes 506 and merged from the upper connecting pipe 509, and finally discharged from the discharge pipe 508 to the inside of the No. 5 low-pressure heater 303 to heat the water. The water will be pumped into the inside of the left low-pressure heater 302 and the inside of the No. 5 low-pressure heater 303 by the water pump 301, and will be heated by the high-pressure heater 305 after passing through the deaerator 304. Finally, the heated water is transported to the inside of the boiler 2 by the water inlet pipe 306 to achieve the effect of preheating.

[0044] Then, when the boiler 2 is in use, the water inlet valve 607 on the heat absorption tube 603 is opened to allow cold water to enter the interior of the heat absorption tube 603. Since the heat absorption tube 603 is attached to the outer wall of the chimney 602 in a spiral line, a large amount of heat will be generated when the chimney 602 exhausts smoke. The heat absorption tube 603 heats the water inside it after absorbing heat, and the amount of water cannot exceed half of the vertical position of the return pipe 604 to prevent the water from being transported to the interior of the steam turbine. The heated water will generate steam, and the hot steam will be connected to the steam turbine through the return pipe 604 to preheat the steam inside the steam turbine, increase the temperature of the water vapor, shorten the heating time, and the amount of water inside the heat absorption tube 603 can be controlled by the drain valve 608. When there is too much water, the drain valve 608 can be opened to drain the water.

[0045] Finally, when the smoke inside the chimney 602 needs to be cleaned, the pipe on the chimney 602 is disassembled, and the hole on the fixing frame 703 is hooked by a hook tool, and the scraper 702 is pulled, so that the scraper 702 can be raised and lowered inside the slide 701. When the scraper 702 is raised and lowered, the smoke on the inner wall of the chimney 602 is cleaned to avoid blockage of the chimney 602, avoid excessive temperature of the outer wall of the chimney 602, and facilitate the full combustion of coal powder inside the furnace.

[0046] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0047] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine, characterized in that: The invention comprises a bottom plate (1), a boiler (2) mounted on the bottom plate (1), a water inlet mechanism (3), and a fuel feed mechanism (4), wherein the fuel feed mechanism (4) is connected to the boiler (2), the water inlet mechanism (3) is connected to the boiler (2), a preheating mechanism (5) is mounted on the fuel feed mechanism (4), and the preheating mechanism (5) is connected to the water inlet mechanism (3); The fuel feeding mechanism (4) comprises two coal mills (401), and four powder pipes (402) are installed in a circular array at the air outlet positions of the two coal mills (401); The preheating mechanism (5) comprises eight heat exchangers (501), the outer walls of the four powder pipes (402) on the two coal mills (401) are all equipped with heat exchangers (501), spiral guide plates (513) are installed between the outer walls of the eight powder pipes (402) and the heat exchangers (501), the bottoms of the four heat exchangers (501) on the same side are all connected to high-temperature steam inlet pipes (502), the bottoms of the four high-temperature steam inlet pipes (502) on the same side are connected to bottom rings (503), a lower connecting pipe (504) is connected between the two bottom rings (503), and a suction pipe (505) is connected to the lower connecting pipe (504), Two inlet steam isolation valves (510) are installed on the lower connecting pipe (504); the tops of the four heat exchangers (501) on the same side are all connected to low-temperature steam outlet pipes (506); the four low-temperature steam outlet pipes (506) on the same side are connected to top rings (507); an upper connecting pipe (509) is connected between the two top rings (507); the upper connecting pipe (509) is connected to a drain pipe (508); two outlet steam isolation valves (511) are installed on the upper connecting pipe (509); and regulating valves (512) are installed on the eight high-temperature steam inlet pipes (502) and the eight low-temperature steam outlet pipes (506); The water inlet mechanism (3) comprises a No. 5 low-pressure heater (303) and a high-pressure heater (305); the No. 5 low-pressure heater (303), the high-pressure heater (305) and a water inlet pipe (306) are installed on the bottom plate (1); one end of the drain pipe (508) is connected to the No. 5 low-pressure heater (303); and the water inlet pipe (306) is connected between the high-pressure heater (305) and the boiler (2).

2. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 1, characterized in that: The extraction pipe (505) is located at the center of the lower connecting pipe (504), and the two inlet steam isolation valves (510) are symmetrically arranged about the extraction pipe (505).

3. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 1, characterized in that: The row pipe (508) is located at the center of the upper connecting pipe (509), and the two outlet steam isolation valves (511) are symmetrically arranged with respect to the row pipe (508).

4. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 2, characterized in that: The fuel feeding mechanism (4) further comprises a collecting box (403), the eight powder pipes (402) are connected to the collecting box (403), the side wall of the collecting box (403) is connected to a fuel delivery pipe (404), a burner (405) is installed at one end of the boiler (2), and the end of the fuel delivery pipe (404) is connected to the burner (405).

5. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 1, characterized in that: The water inlet mechanism (3) further comprises a water pump (301) and a left low-pressure heater (302); a left low-pressure heater (302) connected to a No. 5 low-pressure heater (303) is installed on the bottom plate (1); a deaerator (304) is installed on the bottom plate (1); the No. 5 low-pressure heater (303) is connected to the deaerator (304); and the deaerator (304) is connected to the high-pressure heater (305).

6. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 1, characterized in that: The boiler (2) is provided with a smoke exhaust mechanism (6), the smoke exhaust mechanism (6) comprising a smoke bin (601), the smoke bin (601) being provided at the other end of the boiler (2), the smoke bin (601) being connected to a chimney (602).

7. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 6, characterized in that: The smoke exhaust mechanism (6) further comprises a heat absorbing pipe (603), the outer wall of the chimney (602) being spirally wound with the heat absorbing pipe (603), one end of the heat absorbing pipe (603) being installed with a water inlet valve (607), a sewage pipe (606) being installed on the hollow heat absorbing pipe (603), a sewage valve (608) being installed on the sewage pipe (606), a return pipe (604) of an inverted L-shaped structure being connected to the heat absorbing pipe (603), and a liquid level indicator (605) being installed on the return pipe (604).

8. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 6, characterized in that: A cleaning mechanism (7) is installed inside the chimney (602), and the cleaning mechanism (7) includes four slide grooves (701). Four slide grooves (701) are axially opened in a circular array on the inner wall of the chimney (602), and scrapers (702) of an annular structure are slidably connected inside the four slide grooves (701), and a fixing frame (703) is installed on the scraper (702).

9. The device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to claim 8, characterized in that: The cleaning mechanism (7) further comprises a taking-in opening (704), the taking-in opening (704) being provided at the center of the fixing frame (703), the fixing frame (703) being in a cross-shaped structure, and the scraper (702) being provided with a plurality of holes.

10. The method for operating the device for increasing the outlet temperature of a coal mill by using steam extraction from a steam turbine according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: First, the high-temperature steam of the steam turbine is connected to the extraction pipe (505), and the high-temperature steam is allowed to enter the interior of the two sets of high-temperature steam inlet pipes (502) through the inlet steam isolation valve (510), and then the coal blocks are added to the interior of the two coal mills (401) through the interior of the heat exchanger (501). At this time, the coal powder crushed by the two coal mills (401) enters the interior of the two sets of powder pipes (402), and the coal powder passes through the powder pipes (402) inside the heat exchanger (501) and is heated by the high-temperature steam inside; S2: Then, the pulverized coal heated by the high-temperature steam enters the interior of the collecting box (403), and is finally discharged from the fuel delivery pipe (404) to the interior of the burner (405) for combustion to heat the boiler (2). The high-temperature steam heats the pulverized coal and the low-temperature primary air inside the pulverized coal pipe (402) to become high-temperature primary air, thereby increasing the temperature of the pulverized coal. At this time, the steam discharged from the heat exchanger (501) passes through the spiral guide vane (513) and becomes low-temperature steam. The low-temperature steam is discharged from the low-temperature steam outlet pipe (506) at the top of the heat exchanger (501), and the low-temperature steam enters the interior of the No. 5 low-pressure heater (302) again; S3: Next, the water pump (301) heats the cold water through the left low-pressure heater (302), the fifth low-pressure heater (303), the deaerator (304), and the high-pressure heater (305) in sequence, and turns the cold water into high-temperature water, which is then sent to the boiler (2); S4: Finally, the smoke from the combustion of the boiler (2) is discharged from the smoke exhaust mechanism (6), and the shell of the chimney (602) can absorb heat. Cold water is introduced from the bottom of the heat absorption tube (603). The liquid level display (605) is observed. The water should not exceed half of the vertical position of the return pipe (604). Then, the steam in the cavity of the return pipe (604) can be input into the interior of the steam turbine. If the smoke dust on the inner wall of the chimney (602) needs to be cleaned, the fixed frame (703) is pulled by a tool with a hook to move the scraper (702) on the inner wall of the chimney (602) to clean the smoke dust.

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