A water-coal slurry supercritical hydrothermal combustion device and combustion treatment method

Abstract

The present application belongs to the technical field of clean utilization of coal, and specifically relates to a water-coal slurry supercritical hydrothermal combustion equipment and a combustion treatment method, wherein the combustion equipment includes: an upper pressure-bearing cylinder, including a supercritical hydrothermal combustion chamber, a nozzle fixing cylinder is provided at the top, and a reactant outlet is provided at the bottom; a jet burner, including a water-coal slurry feed port and a fuel inlet, and its outlet end extends from the nozzle fixing cylinder into the supercritical hydrothermal combustion chamber; a lower pressure-bearing cylinder, including a reactant accommodating chamber, a reactant inlet at the top, and a slag discharge port at the bottom, and a reactant gas outlet and an ash water outlet are provided on the side wall, and in addition, the top of the lower pressure-bearing cylinder is connected to the bottom of the upper pressure-bearing cylinder, so that the reactant outlet is connected to the reactant inlet. In the combustion equipment and combustion treatment method of the present application, the oxidation process of the water-coal slurry is carried out in supercritical water, and there is no secondary pollution and a large amount of tail gas. In addition, the carbon dioxide separated by gas-liquid separation is easy to capture and the capture cost is low, and zero emission of carbon dioxide can be achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of clean utilization of coal, and specifically relates to a water-coal slurry supercritical hydrothermal combustion device and a combustion treatment method. Background Art

[0002] Coal resources are an important part of my country's energy and an indispensable factor in my country's industrial production. They play a vital role in my country's industrial production. With the development of the economy and the progress of social industrialization, the demand for coal is increasing.

[0003] However, the combustion of coal will produce pollutants such as nitrogen oxides, sulfides, dust, and carbon dioxide emissions, which will seriously affect air quality. In 2020, my country's total coal consumption was about 3.6 billion tons, and coal emitted about 7.35 billion tons of carbon dioxide a year. In 2020, China's carbon dioxide emissions were about 10.2 to 10.8 billion tons. Therefore, the development of a new type of clean coal utilization technology and equipment without sulfides, nitrogen oxides, dust and carbon dioxide emissions is of great significance to the sustainable development of my country's energy economy and the realization of the "dual carbon" goal.

[0004] At present, the coal utilization technology adopted is high-efficiency coal-burning technology, such as supercritical units, steam-gas combined cycle units, integrated gasification steam-gas combined cycle units, etc., but these equipment still need additional supporting systems such as desulfurization, denitrification and carbon dioxide capture to achieve the goal of ultra-low emissions. However, these additional supporting systems have disadvantages such as complex processes and equipment, high investment and operating costs. Summary of the invention

[0005] In order to solve at least one technical problem existing in the prior art, the present application provides a water-coal slurry supercritical hydrothermal combustion device and a combustion treatment method.

[0006] In a first aspect, the present application discloses a water-coal slurry supercritical hydrothermal combustion device, comprising:

[0007] An upper pressure-bearing cylinder, whose inner cavity serves as a supercritical hydrothermal combustion chamber, a spray hole connected to the supercritical hydrothermal combustion chamber is opened on the top, a nozzle fixing cylinder with openings at both ends is fixedly arranged in the spray hole, and a reactant outlet connected to the supercritical hydrothermal combustion chamber is opened at the bottom of the upper pressure-bearing cylinder;

[0008] A jet burner, the outlet end of which extends into the supercritical hydrothermal combustion chamber through the nozzle fixing tube and is sealed and fixed by the nozzle fixing tube, and the inlet end of the jet burner located outside the upper pressure-bearing tube at least includes a water-coal slurry feed port and a fuel inlet;

[0009] The lower pressure-bearing cylinder has an inner cavity serving as a reactant accommodating chamber, a top opening serving as a reactant inlet, a bottom opening serving as a slag discharge port, and a reaction gas outlet and an ash water outlet communicating with the reactant accommodating chamber are sequentially opened on its side wall from top to bottom. In addition, the top of the lower pressure-bearing cylinder is sealed and fixedly connected to the bottom of the upper pressure-bearing cylinder so that the reactant outlet is communicated with the reactant inlet.

[0010] According to at least one embodiment of the present application, the inner wall of the supercritical hydrothermal combustion chamber is cylindrical, and includes, from bottom to top, an inner diameter expansion section with a linearly gradually increasing inner diameter, a straight pipe section with a constant inner diameter, an inner diameter reduction section with a nonlinearly gradually increasing inner diameter, and a jet burner section with a constant inner diameter.

[0011] According to at least one embodiment of the present application, the upper pressure cylinder is a double-layer structure, comprising:

[0012] An upper pressure-bearing outer cylinder and an upper pressure-bearing inner cylinder are coaxially sleeved, and a sealed cooling water annular gap is formed between the upper pressure-bearing outer cylinder and the upper pressure-bearing inner cylinder, wherein the inner cavity of the upper pressure-bearing inner cylinder serves as the supercritical water thermal combustion chamber;

[0013] A cooling water inlet, which is arranged through the bottom of the side wall of the upper pressure-bearing outer cylinder and communicates with the cooling water annular gap;

[0014] A cooling water outlet is provided through the top of the side wall of the upper pressure-bearing outer cylinder and is communicated with the cooling water annular gap.

[0015] According to at least one embodiment of the present application, the lower pressure cylinder includes, from bottom to top, a slag discharge section with a constant inner diameter, an inner diameter expansion section with a linearly gradually increasing inner diameter, and a straight pipe section with a constant inner diameter, wherein the diameter of the straight pipe section is equal to the diameter of the upper pressure outer cylinder.

[0016] According to at least one embodiment of the present application, the water-coal slurry supercritical hydrothermal combustion equipment further includes:

[0017] A quenching conduit is located in the reactant containing chamber of the lower pressure cylinder. The quenching conduit is fixedly connected to the bottom of the upper pressure cylinder through its open end at the top, and the inner diameter of the open end is the same as the inner diameter of the reactant outlet and is interconnected. In addition, the open end of the quenching conduit at the bottom extends vertically toward the slag discharge port and does not contact the cylinder wall and bottom plate of the lower pressure cylinder.

[0018] According to at least one embodiment of the present application, the water-coal slurry supercritical hydrothermal combustion equipment further includes:

[0019] A high-pressure quenching ring, which is sleeved on the outer wall of one end of the quenching tube close to the reactant outlet, and a plurality of quenching liquid outlets are provided at the contact surface between the high-pressure quenching ring and the quenching tube for connecting the inner ring cavity of the high-pressure quenching ring with the inner cylinder cavity of the quenching tube;

[0020] The quenching liquid delivery pipe has one open end which penetrates the side wall of the lower pressure-bearing cylinder from outside to inside and then extends to communicate with the high-pressure quenching ring, and the other open end is located outside the lower pressure-bearing cylinder as a quenching liquid inlet.

[0021] According to at least one embodiment of the present application, the water-coal slurry supercritical hydrothermal combustion equipment further includes:

[0022] An air duct, whose inner diameter is larger than the outer diameter of the quenching duct and whose outer diameter is smaller than the inner diameter of the lower pressure-bearing cylinder, is coaxially fixedly sleeved on the outside of the quenching duct, so that a sleeve annular gap with upper and lower openings is formed between the inner wall of the air duct and the outer wall of the quenching duct, and an annular quenching chamber is formed between the outer wall of the air duct and the inner wall of the lower pressure-bearing cylinder. In addition, one end of the air duct close to the bottom plate of the lower pressure-bearing cylinder does not contact the cylinder wall and the bottom plate of the lower pressure-bearing cylinder, and at this end, the axial length of the air duct is greater than the axial length of the quenching duct.

[0023] According to at least one embodiment of the present application, the inlet end of the jet burner located outside the upper pressure tube further includes a spare feed port.

[0024] In a second aspect, the present application discloses a method for treating water-coal slurry with supercritical hydrothermal combustion, which uses the water-coal slurry supercritical hydrothermal combustion equipment described in any one of the first aspects to treat the water-coal slurry, comprising the following steps:

[0025] Step 1: injecting the water-coal slurry and the liquid fuel into the jet burner from the water-coal slurry feed port and the fuel inlet respectively to mix, and then spraying the mixed materials into the supercritical hydrothermal combustion chamber from the outlet of the jet burner in the form of mist particles to form a supercritical hydrothermal combustion flame, so that the materials react in supercritical water;

[0026] At the same time, cooling water is circulated into the cooling water annular gap through the cooling water inlet and the cooling water outlet;

[0027] Step 2: When the reaction products in the supercritical hydrothermal combustion chamber flow out through the reactant outlet and flow through the high-pressure quenching ring, a quenching agent is input into the quenching liquid delivery pipe from the outside to cool the reaction products. The reaction products that flow through the high-pressure quenching ring then flow into the quenching conduit for further cooling, so that the reaction products are converted from a supercritical state to a subcritical state;

[0028] Step 3: When the reaction product is converted into a subcritical state, solid, gas and liquid products are formed respectively, wherein

[0029] The solid phase product flows downward into the slag discharge port; the gas phase product flows upward through the sleeve annular gap, and is further condensed into a liquid phase through the quenching chamber; the liquid phase product is discharged through the ash water outlet; and finally the residual gas phase is discharged through the reaction gas outlet.

[0030] According to at least one embodiment of the present application, in step 1, the liquid fuel is liquid oxygen; and

[0031] In the step 1, the reaction temperature in the supercritical hydrothermal combustion chamber is controlled to be no higher than 1000° C. by controlling the flow rate and temperature of the cooling water introduced into the cooling water annulus; and

[0032] In the step 1, the pressure in the supercritical hydrothermal combustion chamber is controlled to be no more than 25 MPa; and

[0033] In the step 1, the ratio of the water-coal slurry and the liquid fuel charged into the jet burner from the water-coal slurry feed port and the fuel inlet is 1 to 10:1; and

[0034] In the step 2, the chiller is industrial water at 25-30°C. By controlling the flow rate of the chiller into the chilling liquid delivery pipe, the temperature of the reaction product after cooling and adjustment by the high-pressure chilling ring is 300-370°C.

[0035] This application has at least the following beneficial technical effects:

[0036] 1) In the water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application, there is no emission of nitrogen oxides, sulfides and dust; specifically, the oxidation process of the water-coal slurry is carried out in supercritical water, so there is basically no secondary pollution and a large amount of tail gas treatment problems, carbon dioxide is easily captured through gas-liquid separation and the capture cost is very low, achieving zero emission of carbon dioxide;

[0037] 2) In the water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application, the coal feed is in the form of water-coal slurry, which eliminates the dust pollution caused by the traditional solid coal transportation, has low requirements on the quality of coal, and can use inferior coal. The water-coal slurry can be prepared using sewage, and the organic pollutants in the sewage can be directly converted into calorific value, reducing the energy consumption of traditional sewage treatment;

[0038] 3) In the water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application, high-speed jet atomization technology is used to fully mix the material and liquid fuel and evenly distribute them in the form of mist-like active particles, which can effectively increase the contact area between the material and the fuel, help the active particles in the fuel to react more fully with the material, and can better utilize the advantages of high fuel activity and improve reaction efficiency;

[0039] 4) In the water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application, due to the precipitation of volatiles during the reaction in the hydrothermal combustion chamber, the reaction slag will form a porous structure, which increases the active sites and is more conducive to the rapid oxidation reaction in the hydrothermal combustion chamber;

[0040] 5) In the water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application, cooling water circulation technology is adopted. The cooling water circulates on the outer wall of the inner tube of the jacket through the annular gap. The reaction temperature in the hydrothermal combustion chamber can be adjusted by controlling the water flow rate, and the problem of uneven reaction temperature distribution and excessive local temperature leading to easy burning through of the inner tube of the jacket can be effectively avoided, and the utilization rate of heat energy in the reaction can be further improved;

[0041] 6) In the water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application, the reaction product can be fully cooled by combining the high-pressure quenching ring with the quenching conduit, thereby avoiding the problem of inorganic salt precipitation;

[0042] 7) In the water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application, a sleeve annulus is set in the water-coal slurry supercritical hydrothermal combustion equipment, so that the residual non-condensable gas (mainly carbon dioxide) after the reaction product is condensed by the quenching tube is discharged through the sleeve annulus after multiple deflections and then recovered through the gas-liquid separator, thereby achieving zero emission of carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a cross-sectional view of the water-coal slurry supercritical hydrothermal combustion equipment of the present application;

[0044] Figure 2 It is a structural schematic diagram of the jet burner in the water-coal slurry supercritical hydrothermal combustion equipment of the present application. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the implementation of the present application clearer, the technical scheme in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the embodiment of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application.

[0046] It should be understood that the technical terms that may be involved in the description of this application, such as "vertical", "horizontal", "up and down", "left and right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of this application.

[0047] The following is combined with Figure 1-Figure 2 The water-coal slurry supercritical hydrothermal combustion equipment and combustion treatment method of the present application are further described in detail.

[0048] In a first aspect, the present application discloses a water-coal slurry supercritical hydrothermal combustion device, which may include an upper pressure-bearing cylinder 1 , a lower pressure-bearing cylinder 3 , and a jet burner 2 .

[0049] Specifically, the upper pressure tube 1 has an inner cavity, which serves as a supercritical hydrothermal combustion chamber 11. In addition, a spray hole connected to the supercritical hydrothermal combustion chamber 11 is provided at the top of the upper pressure tube 1, and a nozzle fixing tube 12 with openings at both ends is fixedly arranged in the spray hole; and a reactant outlet 13 connected to the supercritical hydrothermal combustion chamber 11 is provided at the bottom of the upper pressure tube 1. It should be noted that since a supercritical hydrothermal combustion flame will be formed in the supercritical hydrothermal combustion chamber, and the material will react in supercritical water, the upper pressure tube 1 can be made of known heat-resistant, fire-resistant, corrosion-resistant, and high-pressure-resistant materials as needed.

[0050] The jet burner 2 can adopt a variety of suitable structures. In this embodiment, Figure 2 As shown, the jet burner 2 is in the shape of a straight tube as a whole, and its right side (corresponding to Figure 1 The bottom of the jet burner 2 vertically arranged at the top is the outlet end, and the inlet end on the left side includes a water-coal slurry feed port 21 (and a flange can be set) and a fuel inlet 22 (and a flange can be set) respectively arranged radially; specifically, the outlet end of the jet burner 2 extends into the supercritical hydrothermal combustion chamber 11 through the nozzle fixing tube 12, and is sealed and fixed by the nozzle fixing tube 12, and the water-coal slurry feed port 21 and the fuel inlet 22 are located outside the upper pressure tube 1.

[0051] Furthermore, the lower pressure cylinder 3 has an inner cavity, and has a top opening and a bottom opening; specifically, its inner cavity serves as a reactant accommodating chamber, its top opening serves as a reactant inlet 31, and its bottom opening serves as a slag discharge port 32; and a reaction gas outlet 33 and an ash water outlet 34 connected to the reactant accommodating chamber are sequentially opened on the side wall of the lower pressure cylinder 3 from top to bottom; in addition, the top of the lower pressure cylinder 3 and the bottom of the upper pressure cylinder 1 are fixedly connected by longitudinally arranged high-strength bolts, and the connection is sealed, so that the reactant outlet 13 is connected to the reactant inlet 31.

[0052] It is understandable that the inner cavity of the upper pressure cylinder 1 (i.e., the supercritical hydrothermal combustion chamber 11) of the present application can be configured into a variety of suitable shapes. Figure 1 As shown, the inner wall of the supercritical hydrothermal combustion chamber 11 is preferably cylindrical, and includes, from bottom to top, an inner diameter expansion section with a linearly gradually increasing inner diameter, a straight tube section with a constant inner diameter, an inner diameter reduction section with a nonlinearly gradually increasing inner diameter, and a jet burner section with a constant inner diameter. Such a structure can allow the injected mixed material to form coverage in the maximum range in the supercritical hydrothermal combustion chamber 11. Of course, if the jet burner 2 is set at the top center of the supercritical hydrothermal combustion chamber 11, the coverage effect will be better.

[0053] Similarly, in addition to the inner cavity shape of the upper pressure cylinder 1 of the present application, its specific structure can also be set to various as needed; in this embodiment, Figure 1 As shown, the upper pressure-bearing cylinder 1 is preferably a double-layer structure, and may include an upper pressure-bearing outer cylinder 14 , an upper pressure-bearing inner cylinder 15 , a cooling water inlet 17 , and a cooling water outlet 18 .

[0054] Specifically, the upper pressure-bearing outer tube 14 and the upper pressure-bearing inner tube 15 are coaxially sleeved. Due to the different diameters, a sealed cooling water annular gap 16 can be formed between the upper pressure-bearing outer tube 14 and the upper pressure-bearing inner tube 15. In addition, the inner cavity of the upper pressure-bearing inner tube 15 serves as the above-mentioned supercritical hydrothermal combustion chamber 11, that is, the upper pressure-bearing inner tube 15 adopts the structural form of the above-mentioned expansion section and straight pipe section, while the upper pressure-bearing outer tube 14 can be set to other suitable shapes according to, for example, strength and installation requirements. The cooling water inlet 17 is set through the bottom position of the side wall of the upper pressure-bearing outer tube 14 and is connected to the cooling water annular gap 16; the cooling water outlet 18 is set through the top position of the side wall of the upper pressure-bearing outer tube 14 (for example Figure 1 At the position of the nozzle fixing tube 12, the nozzle fixing tube 12 is also a double-layer structure) and is connected to the cooling water annular gap 16.

[0055] In summary, cooling water can be circulated into the cooling water annular gap 16 through the cooling water inlet 17 and the cooling water outlet 18, and the reaction temperature in the supercritical hydrothermal combustion chamber 11 can be appropriately adjusted by controlling the flow rate and temperature of the cooling water. At the same time, it is beneficial to make the temperature distribution inside the supercritical hydrothermal combustion chamber 11 more uniform, avoiding the problem of excessive reaction temperature and local overheating of the supercritical hydrothermal combustion chamber 11, which may lead to local burning through of the upper pressure inner cylinder 15.

[0056] Similarly, the specific structure and inner cavity shape of the lower pressure-bearing cylinder 3 of the present application can also be set to various shapes as needed; in this embodiment, Figure 1 As shown, the lower pressure cylinder 3 preferably includes, from bottom to top, a slag discharge section with a constant inner diameter, an inner diameter expansion section with a linearly gradually increasing inner diameter, and a straight pipe section with a constant inner diameter, wherein the diameter of the straight pipe section is equal to the diameter of the upper pressure outer cylinder 14, so that the two can be docked, fixed, and sealed.

[0057] Further, such as Figure 1 As shown, the water-coal slurry supercritical hydrothermal combustion equipment of the present application may also include a quenching conduit 41 , a high-pressure quenching ring 42 , a quenching liquid delivery pipe 43 and an air guide pipe 44 .

[0058] Specifically, the quenching conduit 41 is a straight tube, which is located in the reactant containing chamber of the lower pressure cylinder 3; the quenching conduit 41 is fixedly connected to the bottom of the upper pressure cylinder 1 (specifically, the bottom surface of the upper pressure outer cylinder 14) through its open end located at the top by 8 high-strength screws, and the inner diameter of the open end is the same as the inner diameter of the reactant outlet 13 and is interconnected; in addition, the open end of the quenching conduit 41 at the bottom extends vertically toward the slag discharge port 32, and does not contact the cylinder wall and bottom plate of the lower pressure cylinder 3 (that is, the bottom of the quenching conduit 41 is not sealed).

[0059] Furthermore, the high-pressure quenching ring 42 is ring-shaped on the outer wall of one end of the quenching tube 41 close to the reactant outlet 13, and a plurality of quenching liquid outlets for connecting the inner ring cavity of the high-pressure quenching ring 42 with the inner cylinder cavity of the quenching tube 41 are provided at the contact surface between the high-pressure quenching ring 42 and the quenching tube 41; one open end of the quenching liquid delivery pipe 43 passes through the side wall of the lower pressure tube 3 from the outside to the inside and then extends to be connected with the high-pressure quenching ring 42, and the other open end is located on the outside of the lower pressure tube 3 as a quenching liquid inlet.

[0060] In summary, through the combination of the high-pressure quenching ring 42 and the quenching conduit 41, the product after the reaction can be quickly cooled to a subcritical state, thereby avoiding the precipitation of inorganic salts and facilitating the discharge of residues.

[0061] Furthermore, the air guide tube 44 is a straight tube, whose inner diameter is larger than the outer diameter of the quenching tube 41, and whose outer diameter is smaller than the inner diameter of the lower pressure tube 3; specifically, the air guide tube 44 is coaxially fixedly sleeved on the outside of the quenching tube 41, so that a sleeve annular gap 45 with upper and lower openings is formed between the inner wall of the air guide tube 44 and the outer wall of the quenching tube 41, and an annular quenching chamber 46 is formed between the outer wall of the air guide tube 44 and the inner wall of the lower pressure tube 3; in addition, one end of the air guide tube 44 close to the bottom plate of the lower pressure tube 3 (i.e. Figure 1 The bottom end of the air guide tube 44 is not in contact with the wall and bottom plate of the lower pressure tube 3 (i.e., the bottom of the air guide tube 44 is not sealed), and at this end, the axial length of the air guide tube 44 is greater than the axial length of the quenching tube 41, which is conducive to the upward flow of subsequent gas-phase products.

[0062] In summary, through the arrangement of the above-mentioned air duct 44, the non-condensable gas (mainly carbon dioxide) after condensation of the post-reaction gas phase through the quenching duct 41 is discharged through the sleeve annular gap 45 after multiple deflections, and then recovered through the gas-liquid separator to achieve zero emission of carbon dioxide.

[0063] Furthermore, in the water-coal slurry supercritical hydrothermal combustion equipment of the present application, the inlet end of the jet burner 2 may also include a spare feed port 23 .

[0064] In summary, the water-coal slurry supercritical hydrothermal combustion equipment of the present application is an efficient and clean utilization equipment for water-coal slurry. Through high-speed jet atomization technology, the materials and oxygen fuel in the feeding process are fully mixed and present a uniform, mist-like distribution, which maximizes the use of the active molecules of oxygen, so that a supercritical hydrothermal combustion flame is formed in the combustion chamber, thereby improving the efficiency of supercritical hydrothermal combustion. In addition, by circulating cooling water in the cooling water annulus, while lowering the reaction temperature in the supercritical hydrothermal combustion chamber, the problem of uneven temperature distribution inside the combustion chamber, excessive temperature, and local overheating that causes the inner tube of the jacket to burn through is solved. Furthermore, through high-pressure quenching technology, the problem of precipitation of inorganic salts in the supercritical water state and the problem of slag removal that is conducive to the supercritical hydrothermal combustion reaction can be solved.

[0065] In a second aspect, the present application further discloses a method for treating water-coal slurry with supercritical hydrothermal combustion, which uses the water-coal slurry supercritical hydrothermal combustion equipment described in any one of the first aspects to treat the water-coal slurry; specifically, the treatment method comprises the following steps:

[0066] Step 1: inject the water-coal slurry and the liquid fuel into the jet burner 2 from the water-coal slurry feed port 21 and the fuel inlet 22 respectively to mix, and then spray the mixed materials into the supercritical hydrothermal combustion chamber 11 from the outlet of the jet burner 2 in the form of atomized active particles to form a supercritical hydrothermal combustion flame, so that the materials react in supercritical water;

[0067] At the same time, cooling water is circulated into the cooling water annular gap 16 through the cooling water inlet 17 and the cooling water outlet 18 .

[0068] It can be understood that in this step, the outlet of the jet burner 2 sprays out uniform, stable, and active particle-rich mist particles, which is beneficial to increase the contact area between the water-coal slurry and liquid oxygen, and helps the active particles in the liquid oxygen to fully react with the water-coal slurry.

[0069] In addition, in this step, the reaction temperature in the supercritical hydrothermal combustion chamber 11 can be controlled by controlling the flow rate and temperature of the cooling water entering the cooling water annulus 16, which is also beneficial for a more uniform temperature distribution inside the supercritical hydrothermal combustion chamber 11, thereby avoiding the problem of excessive reaction temperature and local overheating of the supercritical hydrothermal combustion chamber 11, which may lead to local burning through of the upper pressure inner tube 15.

[0070] In summary, the liquid oxygen injected through the fuel inlet 22 can collide with the water-coal slurry injected through the water-coal slurry feed port 21 in the jet burner 2 and be fully mixed, thereby improving the uniformity of the distribution of active particles after mixing. Thereafter, the liquid oxygen is finely atomized through the jet burner 2 and transported to the supercritical hydrothermal combustion chamber 11. After high temperature, decomposition, and oxidation, a uniform mixture in a supercritical state with a temperature not higher than 1000°C is formed. This uniform, small-particle supercritical mixture is different from the particle characteristics of conventional pyrolysis. The supercritical particles are small and the temperature distribution is uniform. Therefore, while maintaining highly active particles, it reduces the high-temperature burning of the material caused by local overheating, and avoids the problem of coking and slagging that is easily caused by conventional pyrolysis and other processes.

[0071] Step 2: When the reaction products in the supercritical hydrothermal combustion chamber 11 flow out through the reactant outlet 13 and flow through the high-pressure quenching ring 42, a quenching agent is input into the quenching liquid delivery pipe 43 from the outside to cool the reaction products. The reaction products flowing through the high-pressure quenching ring 42 then flow into the quenching conduit 41 for further cooling, thereby converting the reaction products from a supercritical state to a subcritical state.

[0072] Step 3: When the reaction products are converted into a subcritical state, solid, gaseous and liquid products are formed respectively, wherein the solid products flow downward into the slag discharge port 32; the gaseous products flow upward through the sleeve annular gap 45, and are further condensed into a liquid phase through the quenching chamber 46; the liquid products containing less slag are discharged through the ash water outlet 34; and finally the residual gas phase is discharged through the reaction gas outlet 33.

[0073] In step 2 and step 3, the combination of the high-pressure quenching ring 42 and the quenching tube 41 allows the reaction product to be quickly cooled to a subcritical state, avoiding the precipitation of inorganic salts and facilitating the discharge of residues; in addition, the non-condensable gas (mainly carbon dioxide) condensed by the quenching tube 41 after the reaction gas phase is discharged through the sleeve annular gap 45 after multiple deflections, and then recovered through the gas-liquid separator to achieve zero emission of carbon dioxide.

[0074] Furthermore, in the water-coal slurry supercritical hydrothermal combustion treatment method of the present application, in the above step one, the liquid fuel is liquid oxygen; and the reaction temperature in the supercritical hydrothermal combustion chamber 11 is controlled to be no higher than 1000°C, and the pressure does not exceed 25MPa; and the ratio of water-coal slurry and liquid fuel filled into the injection burner 2 from the water-coal slurry feed port 21 and the fuel inlet 22 is 1 to 10:1.

[0075] Furthermore, in step 2, the chiller is industrial water at 25 to 30°C, and the flow rate of the chiller input into the chilling liquid delivery pipe 43 is controlled so that the temperature of the reaction product after cooling and adjustment by the high-pressure chilling ring 42 is 300 to 370°C.

[0076] In summary, in the water-coal slurry supercritical hydrothermal combustion treatment method of the present application, the treated water-coal slurry is fed at room temperature, and the water-coal slurry enters the supercritical hydrothermal combustion chamber 11 for supercritical water oxidation reaction, and the macromolecular organic matter in the coal is converted into small molecular organic matter and finally converted into CO2 and H2O, sulfide is converted into sulfate, nitride is converted into nitrate and deposited on the residue and discharged, and no gaseous pollutants are discharged. After the exhaust carbon dioxide is separated from the gas and liquid, it is captured and stored at low cost. The entire system has no carbon dioxide emissions, and it is a coal clean utilization system that achieves zero carbon emissions. In addition, resource utilization can be achieved by performing solid-liquid separation on the ash water discharged from the reaction.

[0077] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A water-coal slurry supercritical hydrothermal combustion device, characterized in that: include: An upper pressure-bearing cylinder (1), whose inner cavity serves as a supercritical hydrothermal combustion chamber (11), whose top is provided with an injection hole connected to the supercritical hydrothermal combustion chamber (11), a nozzle fixing cylinder (12) with openings at both ends being fixedly arranged in the injection hole, and a reactant outlet (13) connected to the supercritical hydrothermal combustion chamber (11) being provided at the bottom of the upper pressure-bearing cylinder (1); A jet burner (2), wherein the outlet end of the jet burner (2) extends into the supercritical hydrothermal combustion chamber (11) through the nozzle fixing tube (12) and is sealed and fixed by the nozzle fixing tube (12); and the inlet end of the jet burner (2) located outside the upper pressure tube (1) at least includes a water-coal slurry feed port (21) and a fuel inlet (22); A lower pressure-bearing cylinder (3), whose inner cavity serves as a reactant accommodating chamber, whose top opening serves as a reactant inlet (31), whose bottom opening serves as a slag discharge port (32), and whose side walls are provided with a reactant gas outlet (33) and an ash water outlet (34) in communication with the reactant accommodating chamber in sequence from top to bottom. In addition, the top of the lower pressure-bearing cylinder (3) is sealed and fixedly connected to the bottom of the upper pressure-bearing cylinder (1), so that the reactant outlet (13) is in communication with the reactant inlet (31); A quenching conduit (41) is located in the reactant containing chamber of the lower pressure-bearing cylinder (3); the quenching conduit (41) is fixedly connected to the bottom of the upper pressure-bearing cylinder (1) through its open end located at the top, and the inner diameter of the open end is the same as the inner diameter of the reactant outlet (13) and they are interconnected; in addition, the open end of the quenching conduit (41) located at the bottom extends vertically toward the slag discharge port (32) and does not contact the cylinder wall and bottom plate of the lower pressure-bearing cylinder (3); A high-pressure quenching ring (42) is sleeved on the outer wall of one end of the quenching tube (41) close to the reactant outlet (13), and a plurality of quenching liquid outlets are provided at the contact surface between the high-pressure quenching ring (42) and the quenching tube (41) for connecting the inner ring cavity of the high-pressure quenching ring (42) with the inner cylinder cavity of the quenching tube (41); A quenching liquid delivery pipe (43) has one open end which penetrates the side wall of the lower pressure-bearing cylinder (3) from outside to inside and then extends to communicate with the high-pressure quenching ring (42), and the other open end is located outside the lower pressure-bearing cylinder (3) and serves as a quenching liquid inlet.

2. The water-coal slurry supercritical hydrothermal combustion equipment according to claim 1, characterized in that: The inner wall of the supercritical hydrothermal combustion chamber (11) is cylindrical, and comprises, from bottom to top, an inner diameter expansion section with a linearly increasing inner diameter, a straight tube section with a constant inner diameter, an inner diameter reduction section with a nonlinearly increasing inner diameter, and a jet burner section with a constant inner diameter.

3. The water-coal slurry supercritical hydrothermal combustion equipment according to claim 2, characterized in that: The upper pressure-bearing cylinder (1) is a double-layer structure, comprising: An upper pressure-bearing outer cylinder (14) and an upper pressure-bearing inner cylinder (15) are coaxially sleeved, and a sealed cooling water annular gap (16) is formed between the upper pressure-bearing outer cylinder (14) and the upper pressure-bearing inner cylinder (15), wherein the inner cavity of the upper pressure-bearing inner cylinder (15) serves as the supercritical hydrothermal combustion chamber (11); A cooling water inlet (17) is provided through the bottom of the side wall of the upper pressure-bearing outer cylinder (14) and is communicated with the cooling water annular gap (16); A cooling water outlet (18) is provided through the top of the side wall of the upper pressure-bearing outer cylinder (14) and is communicated with the cooling water annular gap (16).

4. The water-coal slurry supercritical hydrothermal combustion equipment according to claim 3, characterized in that: The lower pressure-bearing cylinder (3) comprises, from bottom to top, a slag discharge section with a constant inner diameter, an inner diameter expansion section with a linear and gradual inner diameter increase, and a straight pipe section with a constant inner diameter, wherein the diameter of the straight pipe section is equal to the diameter of the upper pressure-bearing outer cylinder (14).

5. The water-coal slurry supercritical hydrothermal combustion equipment according to claim 1, characterized in that: Also includes: The air guide tube (44) has an inner diameter greater than the outer diameter of the quenching tube (41) and an outer diameter smaller than the inner diameter of the lower pressure-bearing tube (3). The air guide tube (44) is coaxially fixedly sleeved on the outside of the quenching tube (41), so that a sleeve annular gap (45) with upper and lower openings is formed between the inner wall of the air guide tube (44) and the outer wall of the quenching tube (41), and an annular quenching chamber (46) is formed between the outer wall of the air guide tube (44) and the inner wall of the lower pressure-bearing tube (3). In addition, the end of the air guide tube (44) close to the bottom plate of the lower pressure-bearing tube (3) does not contact the tube wall and the bottom plate of the lower pressure-bearing tube (3), and at this end, the axial length of the air guide tube (44) is greater than the axial length of the quenching tube (41).

6. The water-coal slurry supercritical hydrothermal combustion equipment according to claim 1, characterized in that: The inlet end of the jet burner (2) located outside the upper pressure-bearing cylinder (1) also includes a spare feed port (23).

7. A method for supercritical hydrothermal combustion of coal water slurry, characterized in that: The water-coal slurry is treated by using the water-coal slurry supercritical hydrothermal combustion equipment as claimed in any one of claims 1 to 6, comprising the following steps: Step 1: injecting the water-coal slurry and the liquid fuel into the jet burner (2) from the water-coal slurry feed port (21) and the fuel inlet (22) respectively to mix them, and then spraying the mixed materials into the supercritical hydrothermal combustion chamber (11) in the form of mist particles from the outlet end of the jet burner (2) to form a supercritical hydrothermal combustion flame, so that the materials react in supercritical water; At the same time, cooling water is circulated into the cooling water annular gap (16) through the cooling water inlet (17) and the cooling water outlet (18); Step 2: When the reaction product in the supercritical hydrothermal combustion chamber (11) flows out through the reactant outlet (13) and flows through the high-pressure quenching ring (42), a quenching agent is input from the outside into the quenching liquid delivery pipe (43) to cool the reaction product. The reaction product that flows through the high-pressure quenching ring (42) then flows into the quenching conduit (41) for further cooling, so that the reaction product is converted from a supercritical state to a subcritical state; Step 3: When the reaction product is converted into a subcritical state, solid, gas and liquid products are formed respectively, wherein The solid phase product flows downward into the slag discharge port (32); the gas phase product flows upward through the sleeve annular gap (45) and is further condensed into a liquid phase through the quenching chamber (46); the liquid phase product is discharged through the ash water outlet (34); and finally the residual gas phase is discharged through the reaction gas outlet (33).

8. The method for supercritical hydrothermal combustion of coal water slurry according to claim 7, characterized in that: In the step 1, the liquid fuel is liquid oxygen; and In the step 1, the reaction temperature in the supercritical hydrothermal combustion chamber (11) is controlled to be no higher than 1000° C. by controlling the flow rate and temperature of the cooling water introduced into the cooling water annular gap (16); and In the step 1, the pressure in the supercritical hydrothermal combustion chamber (11) is controlled to be no more than 25 MPa; as well as In the step 1, the ratio of the coal water slurry to the liquid fuel charged into the jet burner (2) from the coal water slurry feed port (21) and the fuel inlet (22) is 1 to 10:1; and In the step 2, the quenching agent is industrial water at 25-30°C. By controlling the flow rate of the quenching agent input into the quenching liquid delivery pipe (43), the temperature of the reaction product after cooling and adjustment by the high-pressure quenching ring (42) is 300-370°C.

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