Coal water slurry preparation system and preparation method

Abstract

The invention provides a coal water slurry preparation system and method, and belongs to the technical field of coal gasification. The coal water slurry preparation system comprises a mixing device, a heating device and an evaporation device which are arranged in sequence; the mixing device is used for mixing raw coal and water to form coal water slurry; the heating device can receive the coal water slurry from the mixing device and can heat the coal water slurry; the evaporation device can receive the coal water slurry heated by the heating device; the evaporation device can increase the temperature of the coal water slurry so as to increase the concentration of the coal water slurry. The concentration of the coal water slurry is increased by using the evaporation device, meanwhile, the viscosity of the coal water slurry is effectively reduced through high temperature generated by the evaporation device, the coal water slurry can still keep good fluidity under the high concentration, the combustion efficiency of the gasification furnace is improved, and therefore the overall economical efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of coal gasification, and particularly to a water coal slurry preparation system and a preparation method thereof. Background Art

[0002] Water coal slurry consists of approximately 62% coal, 38% water, and trace additives, and burns in a gasifier to produce hydrogen and carbon monoxide. This production process is an indispensable part of fields such as synthetic ammonia production, polyurethane manufacturing, and methanol synthesis.

[0003] During the preparation of water coal slurry, increasing the concentration of the water coal slurry helps improve the economic efficiency of production.

[0004] Therefore, how to increase the concentration of water coal slurry during the preparation process is an urgent problem to be solved. Summary of the Invention

[0005] The embodiments of this application provide a water coal slurry preparation system and a preparation method thereof, which can increase the preparation concentration of water coal slurry.

[0006] In a first aspect, the embodiments of this application provide a water coal slurry preparation system, including a mixing device, a heating device, and an evaporation device arranged in sequence;

[0007] The mixing device is used to mix raw coal and water to form water coal slurry;

[0008] The heating device can receive the water coal slurry from the mixing device and heat the water coal slurry;

[0009] The evaporation device can receive the water coal slurry heated by the heating device; the evaporation device can increase the temperature of the water coal slurry to increase the concentration of the water coal slurry.

[0010] In some embodiments of this application, the evaporation device has a first through port;

[0011] The water coal slurry preparation system includes a vacuum device, the intake end of the vacuum device is communicated with the first through port, and the vacuum device can reduce the pressure of the evaporation device.

[0012] In some embodiments of this application, a dust collector is arranged between the evaporation device and the vacuum device;

[0013] The intake end of the dust collector is communicated with the first through port, and the outlet end of the dust collector is communicated with the intake end of the vacuum device.

[0014] In some embodiments of this application, the vacuum device includes a cooler, a liquid ring pump, and a gas-liquid separation tank;

[0015] The intake end of the cooler is communicated with the outlet end of the dust remover, and the cooler is used to cool the gas entering the vacuum device;

[0016] The outlet end of the cooler is communicated with the gas-liquid separation tank, and the gas-liquid separation tank is used to separate the liquid generated by the cooling and liquefaction of the gas;

[0017] The gas communication port of the gas-liquid separation tank is communicated with the liquid ring pump, and the liquid ring pump is used to generate negative pressure.

[0018] In some embodiments of the present application, the evaporation device includes a housing and a heat exchange component;

[0019] The housing is provided with a second through port, and the second through port is communicated with the discharge end of the heating device. The evaporation device receives the water coal slurry heated by the heating device through the second through port;

[0020] The housing is provided with a third through port, and the third through port is communicated with the heat exchange component. The third through port is used to introduce steam, and the evaporation device heats the water coal slurry through the heat exchange component.

[0021] In some embodiments of the present application, the evaporation device includes a stirring component, and the stirring component is arranged in the housing. The stirring component can be used to stir the water coal slurry in the housing.

[0022] In some embodiments of the present application, the heat exchange component includes a steam pipeline and a plurality of heat exchange fins connected to each other;

[0023] The steam pipeline is communicated with the third through port, the heat exchange fins are arranged at intervals, and a heat exchange cavity for accommodating the steam is formed in the heat exchange fins.

[0024] In some embodiments of the present application, a thermometer is connected to the discharge port of the heating device, and the thermometer is used to measure the temperature of the water coal slurry at the discharge port of the heating device.

[0025] In a second aspect, an embodiment of the present application provides a method for preparing water coal slurry, including:

[0026] Using a mixing device to mix raw coal and water to form water coal slurry;

[0027] Heating the water coal slurry from the mixing device through a heating device;

[0028] Evaporating the water in the water coal slurry from the heating device through an evaporation device to increase the concentration of the water coal slurry.

[0029] In some embodiments of the present application, the evaporation device includes a housing, a heat exchange component and a stirring component;

[0030] Evaporating the water in the water slurry from the heating device through an evaporation device, including:

[0031] Accommodating the water slurry from the heating device in the housing, and both the stirring assembly and the heat exchange assembly are in contact with the water slurry;

[0032] Introducing steam into the heat exchange assembly to heat the water slurry through the heat exchange assembly;

[0033] Stirring the water slurry in the housing through the stirring assembly to increase the contact area between the water slurry and the heat exchange assembly.

[0034] The water slurry preparation system and preparation method provided by the embodiments of the present application use an evaporation device to increase the concentration of the water slurry. At the same time, the high temperature generated by the evaporation device effectively reduces the viscosity of the water slurry, enabling it to maintain good fluidity at high concentrations, improving the combustion efficiency of the gasifier, and thus enhancing the overall economy. Description of the Drawings

[0035] The drawings here are incorporated into the specification and form a part of the specification, showing the embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0036] Figure 1 Schematic diagram of a water slurry preparation system provided by an embodiment of the present application;

[0037] Figure 2 Schematic diagram of an evaporation device in a water slurry preparation system provided by an embodiment of the present application.

[0038] Description of the Reference Numerals:

[0039] 100, mixing device; 110, rod mill; 120, drum screen;

[0040] 200, heating device; 210, thermometer; 220, flow meter;

[0041] 300, evaporation device; 310, first port; 320, housing; 330, heat exchange assembly; 331, steam pipeline; 332, heat exchange fins; 340, second port; 350, third port; 360, stirring assembly; 370, fourth port; 380, fifth port;

[0042] 400, vacuum device; 410, cooler; 420, liquid ring pump; 430, gas-liquid separation tank;

[0043] 500, dust collector;

[0044] 600, buffer tank;

[0045] 710. First coal slurry pump; 720. Second coal slurry pump.

[0046] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0047] As mentioned in the background art, in the coal water slurry gasification reaction, water provides hydrogen elements to generate H2. For the overall reaction, water is in excess, and only less than 50% of the water participates in the reaction. The remaining water is converted into steam in the gasifier and heated to 1200 - 1300 °C. This process consumes a large amount of heat energy, resulting in high coal consumption and oxygen consumption in the gasifier. Therefore, reducing the amount of water entering the gasifier, that is, increasing the concentration of the coal water slurry, helps to improve production economy.

[0048] Coal water slurry is a solid-liquid mixture. Considering the differences in coal types, its concentration is usually controlled in the range of 59 - 64%. If the concentration exceeds the upper limit value, it will cause an increase in viscosity, a decrease in fluidity, and difficulties in fluid transportation. After the coal water slurry is sent to the gasifier, it will not only cause equipment blockage, but also result in poor atomization effect and incomplete combustion of the coal water slurry. Therefore, how to achieve the highest preparation concentration of the coal water slurry while ensuring its fluidity is the threshold for increasing the preparation concentration of the coal water slurry.

[0049] A large number of studies have shown that increasing the temperature can effectively improve the fluidity of the coal water slurry.

[0050] In view of this, the embodiments of the present application provide a coal water slurry preparation system and a preparation method. By using an evaporation device, not only can the excess water in the coal water slurry be evaporated to increase its concentration, but also the high temperature generated by the evaporation device effectively reduces the viscosity of the coal water slurry, enabling it to maintain good fluidity at a high concentration, ensuring the obtained high-concentration coal water slurry can be utilized by the subsequent gasifier. By controlling the viscosity and fluidity, the coal water slurry preparation system reduces the risk of equipment blockage in the subsequent transportation and combustion processes; the high-concentration coal water slurry reduces transportation and storage costs, reduces the amount of water entering the gasifier, improves combustion efficiency, and thus enhances the overall economy.

[0051] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all the implementation manners consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0052] The technical solution of the present application and how the technical solution of the present application solves the above technical problems will be described in detail below with specific embodiments. These several specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below with reference to the drawings.

[0053] Referring to Figure 1 , an embodiment of the present application provides a water coal slurry preparation system, which includes a mixing device 100, a heating device 200, and an evaporation device 300 arranged in sequence.

[0054] The mixing device 100 is used to mix raw coal and water to form a water coal slurry.

[0055] The heating device 200 can receive the water coal slurry from the mixing device 100 and can heat the water coal slurry.

[0056] The evaporation device 300 can receive the water coal slurry heated by the heating device 200; the evaporation device 300 can increase the temperature of the water coal slurry to increase the concentration of the water coal slurry.

[0057] It can be known that the mixing device 100 ensures the uniform mixing of coal and water, providing a basis for subsequent water coal slurry preparation steps; the heating device 200 is used to increase the temperature of the water coal slurry and initially increase the concentration of the water coal slurry; the evaporation device 300 increases the coal concentration of the water coal slurry by evaporating part of the water, and at the same time, due to the high temperature generated by evaporation, the fluidity of the water coal slurry can be maintained while the temperature of the water coal slurry is increased.

[0058] Exemplarily, the mixing device includes a rod mill 110 and a vibrating screen 120.

[0059] The raw coal, water, and additives are mixed and ground in the rod mill 110 to prepare a water coal slurry with a concentration of 62%, and then filtered through the vibrating screen 120 to remove large particles, obtaining a uniform water coal slurry.

[0060] It should be noted that the specific structures and connection forms of the rod mill 110 and the vibrating screen 120 refer to the general structural forms in the industry and will not be elaborated here.

[0061] In the process of preparing coal water slurry, additives are used to improve the performance of coal water slurry, including fluidity, stability, combustion efficiency, etc. They mainly include dispersants, stabilizers, thickeners, preservatives, and pH regulators. The main function of the dispersant is to reduce the interaction force between coal particles, prevent particle agglomeration, and prevent the settlement of coal water slurry. It is mainly a class of substances with sulfonic acid groups; the stabilizer is used to prevent the settlement and stratification of coal water slurry during storage and transportation, and maintain its uniformity. It is usually a polymer compound, such as sodium polyacrylate, carboxymethyl cellulose, etc.; the thickener is used to adjust the fluidity of coal water slurry to ensure its flow characteristics in specific applications, such as natural gums (such as guar gum), synthetic polymers, etc.; the preservative is used to prevent microbial contamination of coal water slurry during storage and extend its storage life, such as sodium benzoate, potassium sorbate, etc.; the pH regulator is used to adjust the pH value of coal water slurry to optimize the effect of additives and the stability of coal water slurry. For example, alkaline substances (such as sodium hydroxide) or acidic substances (such as sulfuric acid) are used to adjust the pH value.

[0062] The heating device 200 can use a single-pass shell-and-tube heat exchanger, which consists of an outer shell (shell side) and an internal tube bundle (tube side). Heat exchange is carried out through the tube wall. The diameter of the heating tube bundle is 20 - 25 mm. The coal water slurry is inside the tube bundle of the heating device 200, and steam is inside the shell. Exemplarily, the heating device 200 is placed vertically, with the coal water slurry flowing from bottom to top and the steam flowing from top to bottom. This design can effectively prevent the coal water slurry from getting blocked in the heating device 200.

[0063] Exemplarily, the steam consumed by the heating device 200 is low-grade waste heat with a pressure lower than 8 bar. Low-pressure steam by-produced from the downstream conversion unit or high-flash steam by-produced from the waste water treatment device can be selected to realize the utilization of waste heat, which is more environmentally friendly and can reduce production costs at the same time.

[0064] Low-grade waste heat refers to waste heat with a relatively low temperature and small energy density, which is usually generated as a by-product in industrial processes. The temperature of this waste heat is usually lower than 160 °C and is difficult to be directly used for efficient energy conversion or industrial applications.

[0065] High Flash Steam refers to the steam generated when a liquid (usually water) under high pressure is quickly depressurized to a low-pressure state.

[0066] It should be noted that the conversion unit and the waste water treatment device are not within the scope of protection of the embodiments of this application. They are devices in the next production process of the coal water slurry preparation system and are usually within the same production line. Therefore, the waste heat generated by them can be recycled and used in the coal water slurry preparation system.

[0067] The gasifier converts the water coal slurry into syngas, whose main components are hydrogen (H2) and carbon monoxide (CO). The water coal slurry reacts with oxygen or air in the gasifier, undergoes partial oxidation under high temperature and high pressure conditions, generates syngas, and releases a large amount of heat energy at the same time. The syngas can be used to produce chemicals such as ammonia, methanol and synthetic fuels, and the heat energy can be used for power generation or as fuel for industrial heating.

[0068] The slag and water treatment device is used to treat the solid waste (slag) and waste water generated during the gasification process. The slag and water treatment device cools, separates and treats the slag generated during the gasification process. After the waste water is treated, suspended solids, heavy metals and other pollutants can be removed.

[0069] By using the evaporation device 300, not only can the excess water in the water coal slurry be evaporated to increase its concentration, but also the high temperature generated by the evaporation device 300 effectively reduces the viscosity of the water coal slurry, enabling it to maintain good fluidity at high concentrations, ensuring that a high-concentration water coal slurry that can be utilized by the subsequent gasifier is obtained. By controlling the viscosity and fluidity, the water coal slurry preparation system reduces the risk of equipment blockage during subsequent transportation and combustion; the high-concentration water coal slurry reduces transportation and storage costs, reduces the amount of water entering the gasifier, improves combustion efficiency, and thus enhances the overall economy.

[0070] In some possible embodiments, the water coal slurry preparation system further includes a buffer tank 600 and a first coal slurry pump 710. The feed port of the buffer tank 600 is communicated with the discharge port of the drum screen 120, the discharge port of the buffer tank 600 is communicated with the feed port of the heating device 200, and the first coal slurry pump 710 is arranged on the transportation pipeline between the buffer tank 600 and the heating device 200. The first coal slurry pump 710 is used for pressurizing the transportation pipeline, enabling the water coal slurry to have sufficient pressure to be transported within the water coal slurry preparation system, and the buffer tank 600 can make the water coal slurry produced by the drum screen 120 be pumped by the first coal slurry pump 710 evenly enough.

[0071] In some possible embodiments, the evaporation device 300 has a first port 310.

[0072] The water coal slurry preparation system includes a vacuum device 400. The intake end of the vacuum device 400 is communicated with the first port 310, and the vacuum device 400 can reduce the pressure of the evaporation device 300.

[0073] It can be known that the vacuum device 400 can reduce the pressure inside the evaporation device 300, and reducing the pressure will cause the boiling point of the water coal slurry inside the evaporation device 300 to decrease, thus realizing the evaporation of water at a lower temperature.

[0074] By using a vacuum device 400 to reduce the pressure inside the evaporation device 300, the boiling point of water is lowered, enabling water to evaporate at a lower temperature, improving the evaporation efficiency and reducing energy consumption; by effectively evaporating water, the coal concentration of the coal water slurry is increased, thereby enhancing its calorific value and economy.

[0075] In some possible embodiments, a dust collector 500 is provided between the evaporation device 300 and the vacuum device 400.

[0076] The intake end of the dust collector 500 is connected to the first port 310, and the outlet end of the dust collector 500 is connected to the intake end of the vacuum device 400.

[0077] Exemplarily, the dust collector 500 can be an electrostatic precipitator. An electrostatic precipitator (ESP) is an efficient air pollution control device used to remove solid particulate matter (such as dust and soot) from the gas stream. The gas stream containing dust passes through the corona discharge zone of the electrostatic precipitator. Under the action of a high-voltage electric field, gas molecules are ionized, generating free electrons and ions. Dust particles collide with free electrons and ions and become charged, usually negatively charged. The charged dust particles move towards the dust collection plates under the action of the electric field force and adhere to the plates. By mechanical rapping or other methods, the dust attached to the plates is periodically removed and collected in the ash hopper. The electrostatic precipitator can effectively remove particulate matter of micron size and below, with a dust removal efficiency of over 99%. The resistance when the gas stream passes through is small and will not significantly increase the energy consumption of the system. It can be used in high-temperature, high-humidity, and corrosive gas environments.

[0078] It can be known that the gas phase entraining trace amounts of coal water slurry droplets enters the dust collector 500, and the coal water slurry droplets are removed by electrostatic force to prevent them from entering the vacuum device 400 and avoiding affecting the vacuum device 400.

[0079] The dust collector 500 effectively removes the coal water slurry droplets generated during the evaporation process, preventing these coal water slurry droplets from entering the vacuum device 400, avoiding wear, blockage, and short circuit of related equipment. Therefore, the risk of equipment failure is reduced, and the operating reliability and lifespan of the entire system are improved.

[0080] In some possible embodiments, the vacuum device 400 includes a cooler 410, a liquid ring pump 420, and a gas-liquid separation tank 430.

[0081] The intake end of the cooler 410 is connected to the outlet end of the dust collector 500, and the cooler 410 is used to cool the gas entering the vacuum device 400.

[0082] The outlet end of the cooler 410 is connected to the gas-liquid separation tank 430, and the gas-liquid separation tank 430 is used to separate the liquid generated by the cooling and liquefaction of the gas.

[0083] The gas-phase communication port of the gas-liquid separation tank 430 is connected to the liquid ring pump 420, and the liquid ring pump 420 is used to generate negative pressure.

[0084] It can be known that the cooler 410 promotes the condensation of water vapor in the gas into liquid by reducing the gas temperature; the gas-liquid separation tank 430 effectively separates the condensed water, reduces the water vapor content in the gas, and reduces the pressure in the evaporation device 300 by generating negative pressure, thereby promoting water evaporation.

[0085] The cooler 410 reduces the load of the liquid ring pump 420 by reducing the gas temperature, thereby reducing the energy consumption of the system; the gas-liquid separation tank 430 effectively separates the condensed water, prevents the liquid from entering the liquid ring pump 420, protects the normal operation of the liquid ring pump 420, and improves the stability and reliability of the system.

[0086] Specifically, the vacuum device 400 controls the pressure of the evaporation device 300 at 70 - 80 kPa.

[0087] Such as Figure 2 As shown, in some possible implementation manners, the evaporation device 300 includes a housing 320 and a heat exchange component 330.

[0088] The housing 320 is provided with a second communication port 340, and the second communication port 340 is connected to the discharge end of the heating device 200. The evaporation device 300 receives the water coal slurry heated by the heating device 200 through the second communication port 340.

[0089] The housing 320 is provided with a third communication port 350, and the third communication port 350 is connected to the heat exchange component 330. The third communication port 350 is used to introduce steam, and the evaporation device 300 heats the water coal slurry through the heat exchange component 330.

[0090] It can be known that the housing 320, as the main structure of the evaporation device, accommodates the water coal slurry and the heat exchange component 330; the heating device 200 pre-heats the water coal slurry to increase its temperature to promote the subsequent evaporation process; the heat exchange component 330 further heats the water coal slurry through the steam introduced through the third communication port 350 to promote water evaporation, thereby increasing the concentration of the water coal slurry.

[0091] By using the heat exchange component, the water steam providing the heat source can be separated from the water coal slurry, avoiding the pollution of the heat source to the water coal slurry and causing the reduction of the quality of the water coal slurry.

[0092] Specifically, there are two second communication ports 340, and the two second communication ports 340 are symmetrically arranged at the top of the housing 320. The water coal slurry produced at the discharge end of the heating device 200 is divided into two paths and enters the two second communication ports 340 respectively. Both of the two second communication ports 340 are provided with coal slurry nozzles, and spiral flow channels can be arranged inside the coal slurry nozzles to promote the dispersion and fragmentation of the ejected coal slurry.

[0093] Two symmetrically arranged through ports ensure the uniform distribution of the water coal slurry in the shell, avoiding local overheating or uneven concentration; the spiral flow channel design in the coal slurry nozzle makes the water coal slurry form a rotational movement when ejected, increasing the atomization effect. The water coal slurry has been preliminarily dispersed and broken when entering the evaporation device, reducing the viscosity and enhancing the fluidity; the enhanced atomization effect and uniform distribution contribute to improving the evaporation efficiency, thereby increasing the concentration of the coal slurry.

[0094] It should be noted that the steam introduced through the third through port 350 can also be low-grade waste heat with a pressure lower than 8 bar. Low-pressure steam by-produced in the shift unit or high-flash steam by-produced in the slag water treatment device can be selected to achieve waste heat utilization, which is more environmentally friendly and can reduce production costs at the same time.

[0095] In some possible implementation manners, the coal slurry preparation system further includes a second coal slurry pump 720.

[0096] A fifth through port 380 is provided at the bottom of the shell 320. The fifth through port 380 is used to discharge the water coal slurry. The water coal slurry discharged from the fifth through port 380 will enter the gasifier. A second coal slurry pump 720 is provided in the pipeline between the fifth through port 380 and the gasifier, which helps the water coal slurry to smoothly enter the gasifier.

[0097] In some possible implementation manners, the evaporation device 300 includes a stirring assembly 360. The stirring assembly 360 is arranged in the shell 320, and the stirring assembly 360 can be used to stir the water coal slurry in the shell 320.

[0098] Specifically, the stirring assembly 360 can be a four-fold leaf open turbine type, divided into upper and lower layers, which can effectively promote the circulation of the water coal slurry in the shell 320 and improve the heat transfer effect.

[0099] Exemplarily, the rotation speed range of the stirring assembly 360 is 90 - 150 revolutions per minute.

[0100] By continuously stirring the water coal slurry, the stirring assembly 360 enables it to be uniformly heated, avoiding local overheating or caking, thereby improving the evaporation efficiency; stirring helps to maintain the uniformity of the water coal slurry, prevent the settlement of solid particles, improve the fluidity, and ensure the smoothness of the conveying process; through stirring, the deposition of solid particles on the heating surface is reduced, and the risk of fouling and blockage is lowered; uniform stirring makes the evaporation of water more controllable, thereby more precisely controlling the concentration of the water coal slurry and improving the economic efficiency of production.

[0101] In some possible implementation manners, the heat exchange assembly 330 includes a steam pipeline 331 and a plurality of heat exchange fins 332 that are connected and communicate with each other.

[0102] The steam pipeline 331 is connected to the third through port 350, and the heat exchange fins 332 are arranged at intervals. A heat exchange cavity for accommodating steam is formed in the heat exchange fins 332.

[0103] It can be known that the steam pipeline 331 is used to transport steam and is connected to the third through port 350 to ensure that steam can enter the heat exchange assembly; the multiple heat exchange fins 332 are arranged at intervals to increase the heat exchange area. Through the design of the heat exchange fins, steam flows in the heat exchange cavity and conducts efficient heat exchange with the water slurry.

[0104] Specifically, there are at least 16 heat exchange fins 332, and the heat exchange fins 332 are annularly distributed. The annularly distributed heat exchange fins 332 provide a uniform heat exchange environment, enabling the water slurry to be uniformly heated throughout the evaporation device and promoting the efficient evaporation of water. The design of at least 16 heat exchange fins 332 provides sufficient heat exchange area, and at the same time, the annular distribution makes the structure compact and saves space.

[0105] Exemplarily, the distance between the heat exchange fins 332 is greater than 300 mm to avoid forming a flow dead zone and prevent local overheating or caking.

[0106] The heat exchange fins 332 significantly improve the heat transfer efficiency by increasing the heat exchange area, enabling the water slurry to quickly heat up, promoting water evaporation, and ensuring the fluidity of the water slurry; the design of the heat exchange fins 332 makes the entire heat exchange assembly structure compact, occupying a small space, and at the same time providing a large heat exchange area.

[0107] In some possible implementation manners, the housing 320 is provided with a fourth through port 370. The fourth through port 370 is located at the bottom of the housing 320 and is connected to the heat exchange fins 332 through the steam pipeline 331. The fourth through port 370 is used to discharge the condensate generated by the steam cooling.

[0108] It can be known that according to the thermodynamic principle, steam will condense into liquid during the heat exchange process. The fourth through port 370 is used to discharge the condensate generated by the steam cooling during the heat exchange process. Timely discharging of this condensate can prevent the decline of heat exchange efficiency and ensure the normal operation of the heat exchange assembly 330.

[0109] By timely discharging the condensate, it prevents the condensate from accumulating in the heat exchange fins 332 and keeps the heat exchange surface clean and highly heat transfer efficient; the accumulated condensate may cause corrosion of the heat exchange fins 332 and the steam pipeline 331. By effectively discharging the condensate, the service life of the equipment can be extended; discharging the condensate helps to maintain the stable operation of the system and prevent the decline of heat exchange efficiency and equipment failures caused by the accumulation of condensate.

[0110] In some possible implementation manners, a thermometer 210 is connected to the discharge port of the heating device 200, and the thermometer 210 is used to measure the temperature of the water slurry at the discharge port of the heating device 200.

[0111] Specifically, a thermometer 210 is provided on the outlet pipeline of the heating device 200 to monitor the temperature of the water coal slurry. The steam addition amount entering the heating device 200 is controlled according to the temperature of the water coal slurry, so that the temperature of the coal slurry at the outlet of the heating device 200 is maintained at 80 - 95 °C.

[0112] Through the real-time monitoring of the thermometer 210, the temperature of the water coal slurry can be accurately controlled to ensure that it evaporates within the optimal temperature range; an appropriate temperature helps to reduce the viscosity of the water coal slurry and improve its fluidity, thereby improving the transportation efficiency.

[0113] A flow meter 220 is provided on the inlet pipeline of the heating device 200. The linear velocity of the water coal slurry in the heating device 200 should be controlled within the range of 0.2 - 0.4 m / s. Too high a flow rate will result in a short residence time of the water coal slurry in the heating device 200 and insufficient heating; too low a flow rate will cause the water coal slurry to easily adhere to the pipe wall of the heating device 200, increasing the risk of blockage.

[0114] It should be noted that according to the flow area of the tube bundle of the heating device 200 and the control value of the linear velocity of the coal slurry (0.2 - 0.4 m / s), the corresponding coal slurry flow rate range can be calculated, and the high and low alarm values of the flow rate are set accordingly to keep the linear velocity of the water coal slurry in the heating device 200 within a reasonable range.

[0115] The embodiment of the present application provides a method for preparing water coal slurry, including:

[0116] Using the mixing device 100 to mix raw coal and water to form water coal slurry;

[0117] Heating the water coal slurry from the mixing device 100 by the heating device 200;

[0118] Evaporating the water in the water coal slurry from the heating device 200 by the evaporation device 300 to increase the concentration of the water coal slurry.

[0119] In some possible implementation manners, the evaporation device 300 includes a housing 320, a heat exchange component 330, and a stirring component 360.

[0120] Evaporating the water in the water coal slurry from the heating device 200 by the evaporation device 300 includes:

[0121] Using the housing 320 to hold the water coal slurry from the heating device 200, and both the stirring component 360 and the heat exchange component 330 are in contact with the water coal slurry;

[0122] Introducing steam into the heat exchange component 330 to heat the water coal slurry through the heat exchange component 330;

[0123] The water - coal slurry in the stirring housing 320 is stirred by the stirring assembly 360 to increase the contact area between the water - coal slurry and the heat - exchange assembly 330.

[0124] In some possible embodiments, when evaporating the water in the water - coal slurry from the heating device 200 by the evaporation device 300, it further includes:

[0125] Air is drawn from inside the evaporation device 300 by the vacuum device 400 to reduce the pressure inside the evaporation device 300.

[0126] In some possible embodiments, a method for controlling the concentration of the water - coal slurry in the evaporator 300 is also provided:

[0127] The first step (obtaining the stirring torque values of the stirring assembly 360 at different concentrations of the water - coal slurry): Control the water - coal slurry liquid level to be 300 mm higher than the upper edge of the heat - exchange fins 332. The initial temperature of the water - coal slurry entering the evaporation device 300 is 45 °C, and the stirring speed of the stirring assembly 360 is 110 revolutions per minute;

[0128] Adjust the steam input of the heat - exchange assembly 330, control the concentration of the coal slurry in the evaporation device 300 to be 58%, 59%, 60%, 61%, 62%, 63%, 64% respectively, and record the stirring torque values of the corresponding stirring assembly 360 at the water - coal slurry concentrations of 58%, 59%, 60%, 61%, 62%, 63%, 64%.

[0129] The second step (controlling the concentration of the water - coal slurry in the evaporator 300): Monitor the stirring torque value of the stirring assembly 360 in real - time, and adjust the steam input of the heat - exchange assembly 330 according to the target water - coal slurry concentration until the stirring torque value of the stirring assembly 360 reaches the stirring torque value of the stirring assembly 360 at this target water - coal slurry concentration.

[0130] It should be noted that since the current change of the motor of the stirring assembly 360 is positively correlated with the load torque, by monitoring the current change, the change of the stirring torque can be deduced. The measurement of the stirring torque value of the stirring assembly 360 can be reflected by the current change of the stirring assembly 360.

[0131] In one embodiment:

[0132] The concentration of the coal slurry in the evaporation device 300 is controlled to be 58% respectively, and at this time, the corresponding current value of the motor of the stirring assembly 360 is 15.4 A;

[0133] The concentration of the coal slurry in the evaporation device 300 is controlled to be 59% respectively, and at this time, the corresponding current value of the motor of the stirring assembly 360 is 15.9 A;

[0134] The concentration of the coal slurry in the evaporation device 300 is controlled to be 60% respectively, and at this time, the corresponding current value of the motor of the stirring assembly 360 is 16.6 A;

[0135] The coal slurry concentration in the evaporation device 300 is controlled to be 61% respectively. At this time, the corresponding current value of the motor of the stirring assembly 360 is 17.6 A;

[0136] The coal slurry concentration in the evaporation device 300 is controlled to be 62% respectively. At this time, the corresponding current value of the motor of the stirring assembly 360 is 18.9 A;

[0137] The coal slurry concentration in the evaporation device 300 is controlled to be 63% respectively. At this time, the corresponding current value of the motor of the stirring assembly 360 is 20.7 A;

[0138] The coal slurry concentration in the evaporation device 300 is controlled to be 64% respectively. At this time, the corresponding current value of the motor of the stirring assembly 360 is 23.2 A.

[0139] In this embodiment, a coal water slurry with a concentration of 62% and a viscosity of 710 cP is prepared by the rod mill 110, heated to 90 °C by the heating device 200, heated and concentrated by the evaporation device 300. The temperature of the coal water slurry is 92 °C, the concentration is 64%, and the viscosity is 650 cP. The specific coal consumption of the gasifier is reduced by 17 kg of dry basis coal / kNm 3 of effective gas, and the specific oxygen consumption is reduced by 12 Nm 3 of oxygen / kNm 3 of effective gas, and the carbon conversion rate of the gasifier is increased from 98.0% to 98.3%.

[0140] It should be noted that the specific coal consumption of the gasifier refers to the weight of dry basis coal (the raw material of the gasifier, the raw coal after deducting moisture) required to produce 1 kNm 3 of syngas (the product of the gasifier, mainly hydrogen and carbon monoxide), which is used to measure the utilization efficiency of the raw coal. For example, the specific coal consumption is reduced by 17 kg of dry basis coal / kNm 3 of effective gas, which means that for every 1 kNm 3 of product syngas produced by the gasifier, the consumption of raw coal (after deducting moisture) is reduced by 17 kg on the original basis.

[0141] The specific coal consumption of the gasifier refers to the volume of oxygen (the raw material of the gasifier) required to produce 1 kNm 3 of syngas (the product of the gasifier, mainly hydrogen and carbon monoxide), which is used to measure the utilization efficiency of the raw oxygen. For example, the specific oxygen consumption is reduced by 12 Nm 3 / kNm 3 of effective gas, which means that for every 1 kNm 3 of product syngas produced by the gasifier, the consumption of raw oxygen is reduced by 12 Nm 3 .

[0142] The carbon conversion rate refers to the ratio of the carbon participating in the reaction in the gasifier to the total added carbon, which is used to measure the conversion degree of carbon elements in the gasification process and is usually expressed as a percentage. A higher carbon conversion rate means more carbon participates in the reaction, improving the economy of the gasification process. Increasing the carbon conversion rate can reduce the unreacted solid residue and lower the waste treatment cost.

[0143] By controlling the fluidity of the water-coal slurry in the evaporation device 300, the concentration of the water-coal slurry can be controlled in real time according to the stirring torque value of the stirring component 360 in the evaporator 300. It can be understood that by increasing the stirring torque value of the stirring component 360 for implementation and display, the change in the fluidity of the water-coal slurry is monitored; further, the concentration of the water-coal slurry under this fluidity is obtained through this change in fluidity; further, by controlling the steam addition amount of the stirring component 360 in the evaporation device 300, the water evaporation amount is adjusted, thereby realizing the regulation of the water-coal slurry concentration.

[0144] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0145] In the description of the present invention, it should be understood that the terms "including" and "having" used herein and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices.

[0146] Unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water slurry preparation system, characterized in that, It includes a mixing device (100), a heating device (200) and an evaporation device (300) arranged in sequence; The mixing device (100) is used for mixing raw coal and water to form a water coal slurry; The heating device (200) can receive the water coal slurry from the mixing device (100) and can heat the water coal slurry; The evaporation device (300) can receive the water coal slurry heated by the heating device (200); the evaporation device (300) can increase the temperature of the water coal slurry to increase the concentration of the water coal slurry.

2. The coal water slurry preparation system according to claim 1, characterized in that, The evaporation device (300) has a first port (310); The water coal slurry preparation system includes a vacuum device (400). The intake end of the vacuum device (400) is communicated with the first port (310), and the vacuum device (400) can reduce the pressure of the evaporation device (300).

3. The coal water slurry preparation system according to claim 2, characterized in that A dust collector (500) is arranged between the evaporation device (300) and the vacuum device (400); The intake end of the dust collector (500) is communicated with the first port (310), and the outlet end of the dust collector (500) is communicated with the intake end of the vacuum device (400).

4. The coal water slurry preparation system according to claim 3, characterized in that, The vacuum device (400) includes a cooler (410), a liquid ring pump (420) and a gas-liquid separation tank (430); The intake end of the cooler (410) is connected to the outlet end of the dust collector (500), and the cooler (410) is used for cooling the gas entering the vacuum device (400); The outlet end of the cooler (410) is connected to the gas-liquid separation tank (430), and the gas-liquid separation tank (430) is used for separating the liquid generated by the liquefaction of the cooled gas; The gas-phase port of the gas-liquid separation tank (430) is connected to the liquid ring pump (420), and the liquid ring pump (420) is used for generating negative pressure.

5. The coal water slurry preparation system according to claim 1, characterized in that, The evaporation device (300) includes a housing (320) and a heat exchange component (330); The housing (320) is provided with a second port (340), and the second port (340) is communicated with the discharge end of the heating device (200). The evaporation device (300) receives the water coal slurry heated by the heating device (200) through the second port (340); The housing (320) is provided with a third port (350), and the third port (350) is communicated with the heat exchange component (330). The third port (350) is used for introducing steam, and the evaporation device (300) heats the water coal slurry through the heat exchange component (330).

6. The water coal slurry preparation system according to claim 5, wherein The evaporation device (300) includes a stirring component (360), and the stirring component (360) is arranged in the housing (320). The stirring component (360) can be used for stirring the water coal slurry in the housing (320).

7. The coal water slurry preparation system according to claim 5, characterized in that, The heat exchange component (330) includes a steam pipeline (331) and a plurality of heat exchange fins (332) connected to each other; The steam pipeline (331) is connected to the third port (350), and the heat exchange fins (332) are arranged at intervals. A heat exchange cavity for accommodating steam is formed in the heat exchange fins (332).

8. The coal water slurry preparation system according to claim 4, characterized in that, A thermometer (210) is connected to the discharge port of the heating device (200), and the thermometer (210) is used to measure the temperature of the water-coal slurry at the discharge port of the heating device (200).

9. A method for preparing water coal slurry, characterized in that, Comprising: A mixing device (100) is used to mix raw coal and water to form a water-coal slurry; A heating device (200) heats the water-coal slurry from the mixing device (100); An evaporation device (300) evaporates the water in the water-coal slurry from the heating device (200) to increase the concentration of the water-coal slurry.

10. The preparation method of the water coal slurry according to claim 9, wherein, The evaporation device (300) includes a housing (320), a heat exchange component (330), and a stirring component (360); Evaporating the water in the water-coal slurry from the heating device (200) by the evaporation device (300) includes: The housing (320) accommodates the water-coal slurry from the heating device (200), and both the stirring component (360) and the heat exchange component (330) are in contact with the water-coal slurry; Steam is introduced into the heat exchange component (330) to heat the water-coal slurry through the heat exchange component (330); The stirring component (360) stirs the water-coal slurry in the housing (320) to increase the contact area between the water-coal slurry and the heat exchange component (330).

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