Heat exchange equipment and pulverized coal production system

Abstract

Embodiments of the present application provide a heat exchange device and a pulverized coal production system, and relate to the field of chemical equipment. The structure of the tubular tube heater is improved, the upper layer baffle and the lower layer baffle are arranged on the basis of the first baffle and the second baffle, the upper layer baffle can collect the condensate generated in the cooling process to a greater extent, the generated condensate is discharged from the liquid discharge hole on the upper layer baffle to the lower layer baffle, and is discharged from the bottom liquid outlet on the liquid collection area, so that the resistance drop generated by the condensate not being discharged in time in the cooling process is prevented, and the cooled gas is discharged from the top gas outlet. The optimized heat exchange device can effectively separate the water-containing inert gas generated by the pulverized coal production device, so that the inert gas and water can be recycled in the subsequent process, the water consumption and the inert gas consumption of the whole device are reduced, and the problem of water shortage of the gasification device is solved.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment, and more specifically, to a heat exchange device and a pulverized coal production system. Background Technology

[0002] The coal powder preparation process requires processing through a coal mill and a coal powder collector (bag filter). After filtration, an inert gas containing a certain amount of water vapor and trace oxygen (oxygen content ≤7%) is obtained. A considerable portion of the gas is used to control the humidity and pressure of the circulating gas in the system and is directly discharged into the atmosphere through a regulating valve.

[0003] Due to the significant differences in moisture content among different types of coal, the raw coal currently used directly for coal powder preparation and drying generally has a moisture content of around 20%, while the moisture content after drying is controlled to be below 3%. The vast majority of this moisture is released into the atmosphere with the exhaust gas, which mainly presents the following two problems:

[0004] (1) The large amount of medium-temperature inert gas emitted into the atmosphere will cause a waste of resources, and the system water needs to be purchased from outside. The system replenishment inert gas also comes from the plant area or is purchased from outside, which greatly increases the plant's operating and production costs.

[0005] (2) A lot of fog will be generated in the plant area during winter, which will affect the safe and civilized production of the plant.

[0006] Therefore, as the adaptability of gasifiers to coal gradually widens, the moisture content of coal used for gasification increases, and the requirements for system water replenishment and inert gas replenishment become stringent, recovering moisture from raw coal and generating inert gas are urgent technical problems that need to be solved.

[0007] Therefore, this application is submitted. Summary of the Invention

[0008] The present invention includes, for example, providing a heat exchange device and a pulverized coal production system, which aims to effectively recover and utilize moisture in raw coal and inert gas generated during the pulverized coal preparation process.

[0009] The embodiments of the present invention can be implemented as follows:

[0010] In a first aspect, the present invention provides a heat exchange device, including a tubular heat exchanger, wherein the tubular heat exchanger is provided with a gas inlet, a top gas outlet, a bottom liquid outlet, a cooling medium inlet, and a cooling medium outlet. The gas inlet is used to input water-containing inert gas generated by a pulverized coal production device. The tubular heat exchanger is provided with a plurality of first baffles and a plurality of second baffles. The top of each first baffle is connected to the top inner wall of the tubular heat exchanger and is spaced apart from the bottom inner wall of the tubular heat exchanger.

[0011] The bottom of the inner cavity of the tubular heat exchanger is provided with an upper baffle and a lower baffle. The upper baffle is provided with a drain hole. The bottom of each second baffle is connected to the upper baffle and is spaced apart from the top inner wall of the tubular heat exchanger.

[0012] The lower partition includes a first side plate and a second side plate, both of which are inclined to form a liquid collection area at the bottom wall of the tubular heat exchanger, and the bottom liquid outlet is located in the liquid collection area.

[0013] In an optional embodiment, the upper baffle includes a first inclined section, an intermediate transition section and a second inclined section. The top end of the first inclined section is connected to the side wall of the tubular heat exchanger, the bottom end of the first inclined section is connected to one end of the intermediate transition section, the other end of the intermediate transition section is connected to the bottom end of the second inclined section, and the top end of the second inclined section is connected to the bottom end of the second baffle closest to the top gas outlet.

[0014] The drain hole is located on the intermediate transition section.

[0015] In an optional embodiment, the top end of the first side plate is connected to the side wall of the tubular heat exchanger, and the bottom end of the first side plate is connected to the bottom wall of the tubular heat exchanger cavity; the top end of the second side plate is connected to the side wall of the tubular heat exchanger, and the bottom end of the second side plate is connected to the bottom wall of the tubular heat exchanger cavity, so as to form a liquid collection area at the bottom ends of the first and second side plates.

[0016] In an optional embodiment, a plurality of cleaning and purging pipelines are arranged at intervals from top to bottom inside the tubular heat exchanger. Each cleaning and purging pipeline is provided with a plurality of cleaning and purging ports. The tubular heat exchanger is provided with a main pipeline for supplying cleaning gas and / or cleaning liquid to each cleaning and purging pipeline. The main pipeline is connected to an external constant blowing gas pipeline, an external intermittent purging gas pipeline and an external flushing water pipeline.

[0017] In an optional embodiment, the tubular heat exchanger is further provided with an upper cleaning pipeline for rinsing the upper baffle and a lower cleaning pipeline for rinsing the lower baffle.

[0018] In an optional embodiment, the device further includes a gas-liquid separator and a demister. The bottom liquid outlet of the tubular heat exchanger is connected to the inlet of the gas-liquid separator. The gas-liquid separator is provided with a gas outlet and a liquid outlet. The top gas outlet of the tubular heat exchanger and the gas outlet of the gas-liquid separator are both connected to the demister. The bottom liquid outlet of the demister is connected to the gas-liquid separator.

[0019] In an optional implementation, the liquid outlet of the gas-liquid separator is connected to the upper cleaning pipeline, the lower cleaning pipeline, and the external flushing water pipeline.

[0020] In an optional implementation, the top gas outlet of the demister is divided into at least a first branch, a second branch, and a third branch after passing through a power exhaust fan. The first branch is connected to an external constant blowing gas pipeline and an external intermittent purging gas pipeline. The second branch serves as the sealing protection gas for the coal mill and is connected to the coal mill sealing fan. The third branch serves as the supplementary gas for controlling the dew point temperature of the control system and is connected to the coal mill dilution fan.

[0021] Secondly, the present invention provides a pulverized coal production system, including a heat exchange device according to any of the foregoing embodiments, and further including pulverized coal production equipment, wherein the heat exchange device is used to treat a portion of the water-containing inert gas generated by the pulverized coal production equipment.

[0022] In an optional embodiment, the pulverized coal production equipment includes a coal mill, a hot blast stove, and a pulverized coal collector. The gas outlet of the hot blast stove is connected to the coal mill, the discharge port of the coal mill is connected to the pulverized coal collector, the gas outlet of the pulverized coal collector is connected to a circulating fan, and the outlet of the circulating fan is connected to the gas inlet of the hot blast stove and the tubular heat exchanger.

[0023] The coal mill is connected to the coal mill sealing fan to introduce sealing and protective gas into the coal mill; the hot blast stove is connected to the coal mill dilution fan to introduce supplementary gas for adjusting the dew point into the hot blast stove.

[0024] The beneficial effects of this invention include: by improving the structure of the tubular heat exchanger, an upper baffle and a lower baffle are added on the basis of the first and second baffles. The upper baffle can collect condensate generated during the cooling process to a greater extent. The condensate is discharged from the drain hole on the upper baffle to the lower baffle and then discharged from the bottom liquid outlet on the liquid collection area, preventing the resistance drop caused by the untimely discharge of condensate during the cooling process. The cooled gas is discharged from the top gas outlet. The optimized heat exchange equipment can effectively separate the water-containing inert gas generated by the pulverized coal production equipment, so that the inert gas and water can be recycled and reused in the future, reducing the overall water consumption and inert gas consumption of the unit and solving the problem of water shortage in the gasification unit. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a pulverized coal production system provided in an embodiment of the present invention;

[0027] Figure 2 for Figure 1Schematic diagram of the structure of the heat exchanger;

[0028] Figure 3 for Figure 2 A schematic diagram of a center-tube heat exchanger.

[0029] Icons: 10-Pulverized coal production system; 100-Pulverized coal production equipment; 110-Raw coal bunker; 111-Raw coal bunker filter; 112-Raw coal bunker filter fan; 120-Weighing feeder; 130-Pulverized coal mill; 131-Pulverized coal mill sealing fan; 140-Hot blast furnace; 141-Combustion air fan; 142-Pulverized coal mill dilution fan; 150-Pulverized coal collector; 151-Circulating fan; 200-Heat exchange equipment; 210-Tube heat exchanger; 001-Gas inlet; 002-Top gas outlet; 003-Bottom liquid outlet; 004-Cooling medium inlet; 005-Cooling medium outlet; 006-Condensate pump; 211-First baffle; 212-Second baffle Plate; 213-Upper partition plate; 2131-Drain hole; 2132-First inclined section; 2133-Intermediate transition section; 2134-Second inclined section; 214-Lower partition plate; 2141-First side plate; 2142-Second side plate; 2143-Liquid collection area; 215-Purge and cleaning pipeline; 2151-Purge and cleaning port; 216-Main conveying pipe; 2171-External constant blowing air pipeline; 2172-External intermittent purging air pipeline; 2173-External flushing water pipeline; 2174-Upper cleaning pipeline; 2175-Lower cleaning pipeline; 220-Gas-liquid separator; 221-Gas outlet; 222-Liquid outlet; 230-Demister; 240-Power exhaust fan. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0034] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0035] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0036] Please refer to Figure 1 This embodiment provides a pulverized coal production system 10, including a heat exchanger 200 and a pulverized coal production equipment 100. The heat exchanger 200 is used to process part of the water-containing inert gas generated by the pulverized coal production equipment 100.

[0037] The pulverized coal production equipment 100 includes a raw coal bunker 110, a weighing feeder 120, a coal mill 130, a hot blast stove 140, and a pulverized coal collector 150. Raw coal enters the raw coal bunker 110 for temporary storage. After being weighed by the weighing feeder 120 according to process requirements, it enters the coal mill 130 for pulverization, utilizing the bottom grinding disc and grinding rollers within the coal mill 130. The gas outlet of the hot blast stove 140 is connected to the coal mill 130, the discharge port of the coal mill 130 is connected to the pulverized coal collector 150, the gas outlet of the pulverized coal collector 150 is connected to the circulating fan 151, and the outlet of the circulating fan 151 is connected to the gas inlet 001 of the hot blast stove 140 and the tubular heat exchanger 210. The hot blast furnace 140 provides high-temperature inert gas for drying. The hot inert gas carries qualified coal powder into the coal powder collector 150 (which can be a bag filter) for filtration. The coal powder is then transported downstream. The filtered inert gas, which contains a certain amount of water vapor and trace oxygen (oxygen content ≤7%), is pressurized by the circulating fan 151 (circulating gas). Most of the gas mixes with the hot gas generated by the hot blast furnace 140 (hot inert gas generated by air and fuel gas) and is used as the hot inert gas entering the mill. About 1 / 3 of the gas enters the heat exchange equipment 200 for recycling.

[0038] Specifically, a raw coal silo filter fan 112 and a raw coal silo filter 111 can be installed on the raw coal silo 110 according to process requirements. The raw coal silo filter 111 is used to filter dust generated when the raw coal is fed from the top of the raw coal silo 110. A weighing feeder 120 is set at the bottom outlet of the raw coal silo 110 to accurately weigh the raw coal and transport it to the coal mill 130. The coal mill 130 is an existing raw coal crushing mechanism, in which low-pressure nitrogen and high-temperature inert gas output from the hot blast stove 140 are introduced. The hot blast stove 140 uses the gas input from the combustion air fan 141 for heating. Most of the gas delivered from the circulating fan 151 is mixed with the hot gas generated by the hot blast stove 140 and used as the high-temperature gas entering the mill.

[0039] Specifically, the coal mill 130 is connected to the coal mill sealing fan 131 to introduce sealing protective gas into the coal mill 130. The coal mill 130 requires the coal mill sealing fan 131 to provide sealing protective gas during operation. The hot blast stove 140 is connected to the coal mill dilution fan 142 to introduce supplementary gas for adjusting the dew point into the hot blast stove 140. When the dew point temperature is detected to be too high, the coal mill dilution fan 142 needs to be turned on to add gas to lower the dew point. If the coal mill dilution fan 142 cannot effectively lower the dew point, the nitrogen supplementary gas pipeline is turned on.

[0040] Specifically, the gas output after the pulverized coal collector 150 enters the circulating fan 151. A heat exchanger with self-cleaning and anti-clogging function is installed after the outlet vent regulating valve of the circulating fan 151 to cool the exhaust gas, so that all or most of the water vapor in the exhaust gas is condensed and separated.

[0041] Please combine Figure 1 , Figure 2 and Figure 3 The heat exchange device 200 provided in this embodiment of the invention includes a tubular heat exchanger 210. The tubular heat exchanger 210 is provided with a gas inlet 001, a top gas outlet 002, a bottom liquid outlet 003, a cooling medium inlet 004, and a cooling medium outlet 005. The gas inlet 001 is used to input the water-containing inert gas generated by the pulverized coal production equipment 100. That is, part of the water-containing inert gas output from the circulating fan 151 enters the tubular heat exchanger 210 through the gas inlet 001 for cooling, so that all or most of the water vapor is condensed and separated. The condensed liquid is output from the bottom liquid outlet 003. During this process, the condensate also washes the exhaust gas. The gas is output from the top gas outlet 002, realizing the separation of water and inert gas so that they can be recycled later. The cooling medium inlet 004 is used to transport the cooling medium (such as circulating water) to the tube side of the tubular heat exchanger 210. After being heated, it is output from the cooling medium outlet 005 for subsequent pipeline recovery.

[0042] In some embodiments, the heat exchange device 200 further includes a gas-liquid separator 220 and a demister 230. The bottom liquid outlet 003 of the tubular heat exchanger 210 is connected to the inlet of the gas-liquid separator 220. The gas-liquid separator 220 is provided with a gas outlet 221 and a liquid outlet 222. The top gas outlet 002 of the tubular heat exchanger 210 and the gas outlet 221 of the gas-liquid separator 220 are both connected to the demister 230. The bottom liquid outlet 003 of the demister 230 is connected to the gas-liquid separator 220. The condensate output from the tubular heat exchanger 210 carries a small amount of gas and flows into the gas-liquid separator 220 by gravity. The separated gas and the gas output from the tubular heat exchanger 210 enter the demister 230 together for water removal. Specifically, the demister 230 can be a general high-efficiency demister.

[0043] In some embodiments, the tubular heat exchanger 210 is provided with a plurality of first baffles 211 and a plurality of second baffles 212. The top of each first baffle 211 is connected to the top inner wall of the tubular heat exchanger 210 and is spaced apart from the bottom inner wall of the tubular heat exchanger 210. The bottom of the inner cavity of the tubular heat exchanger 210 is provided with an upper baffle 213 and a lower baffle 214. The upper baffle 213 is provided with a drain hole 2131. The bottom of each second baffle 212 is connected to the upper baffle 213 and is spaced apart from the top inner wall of the tubular heat exchanger 210. The lower baffle 214 includes a first side plate 2141 and a second side plate 2142. The first side plate 2141 and the second side plate 2142 are both inclined to form a liquid collection area 2143 at the bottom wall of the tubular heat exchanger 210. The bottom liquid outlet 003 is located in the liquid collection area 2143. In this embodiment of the invention, an upper baffle 213 and a lower baffle 214 are introduced into the tubular heat exchanger 210, based on the first baffle 211 and the second baffle 212. The upper baffle 213 separates the heat exchanger from the lower baffle, trapping the generated condensate and allowing the gas to be cooled along a predetermined path. The condensate trapped on the upper baffle 213 is discharged from the drain hole 2131 onto the lower baffle 214 and then discharged from the bottom liquid outlet 003 on the liquid collection area 2143, preventing the resistance drop caused by the untimely discharge of condensate during the cooling process.

[0044] In some embodiments, the upper baffle 213 includes a first inclined section 2132, an intermediate transition section 2133, and a second inclined section 2134. The top end of the first inclined section 2132 is connected to the side wall of the tubular heat exchanger 210, the bottom end of the first inclined section 2132 is connected to one end of the intermediate transition section 2133, the other end of the intermediate transition section 2133 is connected to the bottom end of the second inclined section 2134, and the top end of the second inclined section 2134 is connected to the bottom end of the second baffle 212 closest to the top gas outlet 002. A drain hole 2131 is located on the intermediate transition section 2133. At the very end, the gas exits from the top along a predetermined route and is not easily carried out by the liquid. The upper baffle 213 is connected to the second baffle 212 closest to the top gas outlet 002, thus sealing off the area from the end to this second baffle 212.

[0045] Specifically, the intermediate transition section 2133 can be horizontally positioned, but is not limited to this. The upper partition 213 can be fixed in any way, including by welding.

[0046] In some embodiments, the top end of the first side plate 2141 is connected to the side wall of the tubular heat exchanger 210, and the bottom end of the first side plate 2141 is connected to the bottom wall of the cavity of the tubular heat exchanger 210; the top end of the second side plate 2142 is connected to the side wall of the tubular heat exchanger 210, and the bottom end of the second side plate 2142 is connected to the bottom wall of the cavity of the tubular heat exchanger 210, so as to form a liquid collection area 2143 at the bottom ends of the first side plate 2141 and the second side plate 2142. The first side plate 2141 and the second side plate 2142 can be symmetrically arranged, with the middle being lower and the two sides being higher, so as to collect the condensate to a greater extent near the bottom liquid outlet 003, and then connect it to the gas-liquid separator 220 through a connecting pipe.

[0047] To prevent the small amount of dust contained in the water-containing inert gas from depositing on the cooling pipes and inner wall of the tubular heat exchanger 210 and affecting the heat exchange effect, multiple cleaning pipes 215 are arranged at intervals from top to bottom inside the tubular heat exchanger 210. Each cleaning pipe 215 is equipped with multiple cleaning ports 2151. The tubular heat exchanger 210 is equipped with a main supply pipe 216 for supplying cleaning gas and / or cleaning fluid to each cleaning pipe 215. The main supply pipe 216 is connected to an external constant blowing gas pipe 2171, an external intermittent purging gas pipe 2172, and an external flushing water pipe 2173. Cleaning gas and / or cleaning fluid can be introduced into the tubular heat exchanger 210 through the main supply pipe 216 to clean the outer wall of the pipes and the inner wall of the cavity. The cleaning and purging pipe 215 extends from one end of the inner cavity of the tubular heat exchanger 210 to the opposite end to thoroughly clean or purge the interior of the tubular heat exchanger 210. The number of cleaning and purging pipes 215 can be set as needed to prevent the accumulation of micro-dust.

[0048] Specifically, the number of cleaning ports 2151 on the cleaning pipeline 215 is unlimited, and their orientation can be multiple to expand the cleaning or purging range. The external constant blowing air pipeline 2171, the external intermittent purging air pipeline 2172, and the external flushing water pipeline 2173 form an online self-cleaning system, enabling online intelligent operation and automatic self-cleaning, ensuring the heat exchanger's normal operation throughout the entire process of the unit's operation. The external constant blowing air pipeline 2171 is a normally open pipeline to prevent blockage of the cleaning ports 2151; the external intermittent purging air pipeline 2172 and the external flushing water pipeline 2173 can be opened or closed by program control, mainly based on time control and differential pressure control. Normally, time control is used for purging and flushing; when the differential pressure across the heat exchanger exceeds a certain value, the program automatically switches to differential pressure control; flushing can be used alone, or a combination of purging and cleaning can be used.

[0049] Furthermore, the tubular heat exchanger 210 is also equipped with an upper cleaning pipe 2174 for rinsing the upper baffle 213 and a lower cleaning pipe 2175 for rinsing the lower baffle 214. The upper cleaning pipe 2174 and the lower cleaning pipe 2175 can be installed on both sides and can be opened as needed to effectively remove the dust that falls on the upper baffle 213 and the lower baffle 214.

[0050] In some embodiments, the liquid outlet of the gas-liquid separator 220 is connected to the upper cleaning pipeline 2174, the lower cleaning pipeline 2175, and the external flushing water pipeline 2173 to recycle the separated condensate, maximizing the recovery of moisture from the raw coal. In addition, most of the condensate is sent to the gasification system as makeup water, improving the system water quality and saving a significant amount of raw water or demineralized water.

[0051] Specifically, the reclaimed water pressurized by the condensate pump 006 is periodically and intermittently opened by the program to flush the upper baffle 213, preventing the accumulation of dust and sludge and clogging of the drain hole 2131 at the bottom of the baffle. At the same time, the reclaimed water pressurized by the condensate pump 006 is periodically and intermittently opened by the program to flush the lower baffle 214, preventing the accumulation of dust and sludge and clogging of the drain outlet at the bottom of the baffle. The flushed dust and sludge enter the gas-liquid separator 220 and are pumped to the gasification system, and finally discharged to the outside through the sedimentation system.

[0052] In some embodiments, to ensure that the exhaust gas overcomes the heat exchanger resistance drop and can be discharged normally without affecting the normal operation of the circulating gas system, a power exhaust fan 240 is added downstream of the demister 230. The top gas outlet 002 of the demister 230 is pressurized by the power exhaust fan 240 and divided into at least a first branch, a second branch, and a third branch. The first branch is connected to the external constant blowing gas pipeline 2171 and the external intermittent purging gas pipeline 2172, and is used as purging gas for cleaning. The second branch is connected to the coal mill sealing fan 131 as the sealing protection gas of the coal mill 130, and is used as nitrogen for the coal mill sealing fan 131. The third branch is connected to the coal mill dilution fan 142 as the supplementary gas for controlling the dew point temperature of the control system, and is used as nitrogen for dilution of the coal mill dilution fan 142. The remaining part is discharged at a high point based on the differential pressure or pressure control between the system pressure and the inlet pressure of the tubular heat exchanger 210. By recycling the separated inert gas, the goal of simultaneously recovering water and gas is achieved, while solving the problem of leakage and spillage on site, thus enabling the safe, stable, civilized, and long-term operation of the equipment.

[0053] It should be added that most of the exhaust gas after being pressurized by the power exhaust fan 240 is vented at the high point through the pressure regulating valve. The opening of the control valve is controlled based on the pressure difference between the circulating gas at the mill outlet and the exhaust gas at the outlet of the tubular heat exchanger 210, ensuring that excess exhaust gas is discharged in a timely manner and does not affect the system operation. At the same time, to prevent blockage or liquid seal in the exhaust gas dehydration system from affecting the stable operation of the pulverized coal preparation system, a branch line with a regulating valve is installed between the inlet of the tubular heat exchanger 210 and the outlet of the demister 230. The opening of the regulating valve is based on the pressure difference between the inlet of the tubular heat exchanger 210 and the outlet of the demister 230. The differential pressure control system ensures that the valves are fully closed within the specified differential pressure range. When the differential pressure exceeds the set value, the regulating valve automatically adjusts its opening to control the differential pressure. This system maximizes the recovery of high-quality water and inert gas, ensuring the stable operation of the coal preparation unit. Simultaneously, the recovered high-quality water is sent to the gasification system as makeup water, which not only saves on system makeup water but also ensures that the hardness and salinity of the added water meet the demineralized water standards, greatly improving the system's water quality. This enhances the safety and stability of the gasification furnace system and the entire unit, ensures the online operating rate of the entire unit, and reduces the unit product production cost.

[0054] It should be added that, taking a gasifier with 2000 t / d of raw coal and a moisture content of 20% as an example, after coal grinding and drying, the moisture content is controlled to be below 3% before entering the furnace. Therefore, the exhaust gas carries away approximately 340 t / d of water, resulting in an annual water discharge of over 100,000 tons. The recovery rate is greater than 70%, and the annual by-product soft water exceeds 70,000 tons. At the same time, it saves at least 6000 Nm³ of low-pressure nitrogen. 3 With a cost of 0.05 yuan per hour for low-pressure nitrogen, the annual economic cost savings would be approximately 2.4 million yuan.

[0055] In summary, the embodiments of the present invention provide a heat exchange device and a pulverized coal production system. Through special design and process layout of the heat exchanger, and through the specially designed heat exchanger, high-quality dust-containing demineralized water is recovered as an external makeup water source for the gasification system, saving raw water and demineralized water, reducing water consumption per unit product, greatly reducing the overall production cost of the device, and at the same time reducing the hardness of the water in the gasification system, thoroughly improving the water quality, and ensuring the safe, stable and long-term operation of the device.

[0056] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A heat exchange device, characterized in that, The device includes a tubular heat exchanger, which is provided with a gas inlet, a top gas outlet, a bottom liquid outlet, a cooling medium inlet, and a cooling medium outlet. The gas inlet is used to input water-containing inert gas generated by the pulverized coal production equipment. The tubular heat exchanger is provided with a plurality of first baffles and a plurality of second baffles. The top of each first baffle is connected to the top inner wall of the tubular heat exchanger and is spaced apart from the bottom inner wall of the tubular heat exchanger. The bottom of the inner cavity of the tubular heat exchanger is provided with an upper baffle and a lower baffle. The upper baffle is provided with a drain hole. The bottom of each second baffle is connected to the upper baffle and is spaced apart from the top inner wall of the tubular heat exchanger. The lower partition includes a first side plate and a second side plate, both of which are inclined to form a liquid collection area at the bottom wall of the tubular heat exchanger, and the bottom liquid outlet is located in the liquid collection area. The upper baffle includes a first inclined section, an intermediate transition section and a second inclined section. The top end of the first inclined section is connected to the side wall of the tubular heat exchanger, the bottom end of the first inclined section is connected to one end of the intermediate transition section, the other end of the intermediate transition section is connected to the bottom end of the second inclined section, and the top end of the second inclined section is connected to the bottom end of the second baffle closest to the top gas outlet. The drain hole is located on the intermediate transition section.

2. The heat exchange device according to claim 1, characterized in that, The top end of the first side plate is connected to the side wall of the tubular heat exchanger, and the bottom end of the first side plate is connected to the bottom wall of the tubular heat exchanger cavity; the top end of the second side plate is connected to the side wall of the tubular heat exchanger, and the bottom end of the second side plate is connected to the bottom wall of the tubular heat exchanger cavity, so as to form the liquid collection area at the bottom ends of the first side plate and the second side plate.

3. The heat exchange device according to claim 1, characterized in that, The tubular heat exchanger is provided with multiple cleaning and purging pipelines arranged at intervals from top to bottom. Each cleaning and purging pipeline is provided with multiple cleaning and purging ports. The tubular heat exchanger is provided with a main pipeline for supplying cleaning gas and / or cleaning liquid to each cleaning and purging pipeline. The main pipeline is connected to an external constant blowing gas pipeline, an external intermittent purging gas pipeline, and an external flushing water pipeline.

4. The heat exchange device according to claim 3, characterized in that, The tubular heat exchanger is also equipped with an upper cleaning pipeline for rinsing the upper baffle and a lower cleaning pipeline for rinsing the lower baffle.

5. The heat exchange device according to claim 4, characterized in that, It also includes a gas-liquid separator and a demister. The bottom liquid outlet of the tubular heat exchanger is connected to the inlet of the gas-liquid separator. The gas-liquid separator is provided with a gas outlet and a liquid outlet. The top gas outlet of the tubular heat exchanger and the gas outlet of the gas-liquid separator are both connected to the demister. The bottom liquid outlet of the demister is connected to the gas-liquid separator.

6. The heat exchange device according to claim 5, characterized in that, The liquid outlet of the gas-liquid separator is connected to the upper cleaning pipeline, the lower cleaning pipeline, and the external flushing water pipeline.

7. The heat exchange device according to claim 5, characterized in that, The top gas outlet of the demister is divided into at least a first branch, a second branch, and a third branch after passing through a power exhaust fan. The first branch is connected to the external constant blowing gas pipeline and the external intermittent purging gas pipeline. The second branch serves as the sealing protection gas for the coal mill and is connected to the coal mill sealing fan. The third branch serves as the supplementary gas for controlling the dew point temperature of the control system and is connected to the coal mill dilution fan.

8. A pulverized coal production system, characterized in that, The heat exchange device includes any one of claims 1-7, and further includes pulverized coal production equipment, wherein the heat exchange device is used to treat a portion of the water-containing inert gas generated by the pulverized coal production equipment.

9. The pulverized coal production system according to claim 8, characterized in that, The pulverized coal production equipment includes a coal mill, a hot air furnace, and a pulverized coal collector. The gas outlet of the hot air furnace is connected to the coal mill, the discharge port of the coal mill is connected to the pulverized coal collector, the gas outlet of the pulverized coal collector is connected to a circulating fan, and the outlet of the circulating fan is connected to the gas inlet of the hot air furnace and the tubular heat exchanger. The coal mill is connected to the coal mill sealing fan to introduce sealing and protective gas into the coal mill; the hot blast stove is connected to the coal mill dilution fan to introduce supplementary gas for adjusting the dew point into the hot blast stove.

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