阅读说明：本技术 过热近临界水中煤氧化脱硫方法与装置 (Method and device for oxidizing and desulfurizing coal in overheated near-critical water ) 是由 赵光明 李斌 柴涛 李娜 于 2021-09-29 设计创作，主要内容包括：本发明涉及煤洁净利用技术,属于环境保护技术中的煤燃烧前脱硫领域,具体为一种利用过热近临界水氧化脱除煤中硫的工艺和方法,特别适用于含有机硫而难以用通常洗选、重力分选等方法脱硫的高硫煤种。核心方案是使用高温高压过热蒸汽和氧化剂,在工作温度T：400～600℃,工作压力P：10～20MPa条件下对含硫煤粉进行脱硫处理。本发明方案可以适用于各种高硫煤的燃烧前脱硫,有效去除其中以各种形式存在的硫分。与超临界水氧化法相比,本发明的方法能降低对反应器和预热器材料的要求,降低因高压导致反应容器腐蚀带来的经济损失,提高了系统的安全性与稳定性,具有较大的技术经济优势。(The invention relates to a clean coal utilization technology, belongs to the field of coal desulfurization before combustion in the environment protection technology, in particular to a process and a method for removing sulfur in coal by using superheated near-critical water for oxidation, and is particularly suitable for high-sulfur coal which contains organic sulfur and is difficult to desulfurize by using common washing, gravity separation and other methods. The core scheme is that high-temperature high-pressure superheated steam and an oxidant are used, and the temperature of the working temperature T: 400-600 ℃, working pressure P: and (3) carrying out desulfurization treatment on the sulfur-containing coal powder under the condition of 10-20 MPa. The scheme of the invention can be suitable for desulfurization before combustion of various high-sulfur coals and effectively remove sulfur components in various forms. Compared with the supercritical water oxidation method, the method disclosed by the invention can reduce the requirements on materials of a reactor and a preheater, reduce economic loss caused by corrosion of a reaction vessel due to high pressure, improve the safety and stability of the system and have greater technical and economic advantages.)

1. The utility model provides a device that utilizes overheated near critical water oxidation desorption sulphur in coal which characterized in that: including process water tank (1), pre-heater (3), reactor (6), oxygen jar (9), cooling pressure reducer (13), process water tank (1) connect pre-heater (3), pre-heater (3) connection reactor (6), reactor (6) connection cooling pressure reducer (13) through high-pressure intake pump (2), cooling pressure reducer (13) connect vapour and liquid separator (16), reactor (6) be cylindrical intermittent type reation kettle, set up support (7) of a plurality of layers of area silk screen dish in reactor (6), oxygen jar (9) and reactor (6) are connected.

2. The apparatus for removing sulfur in coal by using superheated near-critical water oxidation according to claim 1, characterized in that: preheater (3) export back pressure valve (5) through the preheater and connect reactor (6), oxygen jar (9) connect through oxygen pump (8) and reactor (6), reactor (6) below be equipped with raffinate drain valve (10), reactor (6) connect cooling pressure reducer (13) through reactor outlet valve (12), cooling pressure reducer (13) connect vapour and liquid separator (16) through back pressure valve (15), the upper portion of vapour and liquid separator (16) is gas phase export (17), the lower part is liquid phase export (18).

3. A method for removing sulfur in coal by using superheated near-critical water through oxidation uses high-temperature high-pressure superheated steam and an oxidant, and the ratio of the temperature of the superheated steam to the oxidant is as follows: 400-600 ℃, working pressure P: and (3) carrying out desulfurization treatment on the sulfur coal powder under the condition of 10-20 MPa.

4. The method for removing sulfur in coal by using superheated near-critical water oxidation as claimed in claim 3, which is characterized in that: the oxidant is oxygen or hydrogen peroxide.

5. The method for removing sulfur in coal by using superheated near-critical water oxidation as claimed in claim 3, which is characterized in that: utilize pre-heater (3) to add water and generate high temperature high pressure superheated steam, place on taking silk screen dish support (7) in reactor (6) and contain the sulphur buggy, let in reactor (6) with high temperature high pressure superheated steam, control inside operating temperature T: 400-600 ℃, working pressure P: 10-20MPa, introducing high-temperature high-pressure superheated steam into the reactor (6), introducing oxygen in an oxygen tank (9) into the reactor (6), desulfurizing the coal powder in the reactor for 1-10 minutes, after the coal desulfurization reaction is finished, opening the reactor after a reaction system reaches normal temperature and normal pressure through a temperature reduction pressure reducer (13), and taking out desulfurized coal powder.

6. The method for removing sulfur in coal by using superheated near-critical water oxidation as claimed in claim 4 or 5, which is characterized in that: the ratio of the amount of the introduced oxygen to the amount of S in the coal powder is a mol ratio, the excess oxygen is calculated by using sulfate radicals generated by sulfur oxidation products, and the peroxide coefficient is 1.2-1.5.

7. The method for removing sulfur in coal by using superheated near-critical water oxidation as claimed in claim 4, which is characterized in that: the hydrogen peroxide is selected to be stirred with the coal powder and put in the reactor when the coal powder is put in the reactor.

8. The apparatus for removing sulfur in coal by using superheated near-critical water oxidation according to claim 1, characterized in that: the preheater (3) and the reactor (6) are both cylindrical and are made of nickel-based corrosion-resistant steel NS 336.

9. The apparatus for removing sulfur in coal by using superheated near-critical water oxidation according to claim 1, characterized in that: a heating sleeve (4) is arranged outside the preheater (3) and is heated by adopting far infrared.

Technical Field

The invention relates to a clean coal utilization technology, belongs to the field of coal desulfurization before combustion in the environment protection technology, in particular to a process and a method for removing sulfur in coal by using superheated near-critical water for oxidation, and is particularly suitable for high-sulfur coal which contains organic sulfur and is difficult to desulfurize by using common washing, gravity separation and other methods.

Background

Coal is one of the most important fossil fuels, the energy consumption pattern taking coal as the leading position is basically not changed in a period of time in the future, but the traditional flame combustion mode of coal brings serious environmental pollution for a long time, and especially air pollutants such as sulfur dioxide generated by the combustion of the coal have great threats to human health and ecological environment. With the increasingly strict environmental requirements and the increasingly strict emission standards of flue gas generated after coal combustion, the conventional flue gas desulfurization technology has shown a tendency that the emission standards are difficult to meet. For this reason, desulfurization of coal before combustion is newly considered.

There are four main forms of sulfur in coal: inorganic sulfur (FeS as pyrite sulfur)₂Typical representatives), sulfate sulfur, organic sulfur, and elemental sulfur. The sulfate sulfur directly enters ash without removal after combustion, and the rest three forms of sulfur are oxidized into sulfur dioxide in the combustion and enter flue gas, and become air pollutants after being discharged. Currently, the pre-combustion desulfurization of coal is mainly to remove pyrite sulfur FeS in the coal through washing or gravity separation₂Is typically represented by inorganic sulfur. Since the pyrite sulfur is generally in an independent dispersed distribution in the coal species, and is heavier and harder than the coal, it can be removed from the coal species by a simple physical method. However, the organic sulfur in coal usually exists in various functional groups, which form complex molecules with organic matters in coal, and is difficult to remove by common coal washing or gravity separation methods. The physical and chemical characteristics of organic sulfur and elemental sulfur are technical obstacles which are difficult to solve by the common coal removal technology before combustion, so that the technology is forced to be stopped.

The supercritical water oxidation technology is a novel organic matter treatment technology, and the principle is that supercritical water is used as a reaction medium, the pressure is generally 25 MPa-30 MPa, and organic matters and an oxidant are subjected to a homogeneous phase strong oxidation reaction in the supercritical water medium. However, the problems of high investment, high energy consumption and high operation cost caused by high pressure in the technology and two technical problems of salt crystallization and equipment corrosion seriously restrict the general popularization and application of the technology.

Therefore, the invention discloses a process and a method for removing sulfur in coal by using superheated near-critical water through oxidation, which can reduce the requirements on reaction vessel materials and the economic loss caused by reactor corrosion due to high pressure on the premise of achieving the aim of desulfurization, and have great technical and economic advantages.

Disclosure of Invention

The invention aims to solve the problem that organic sulfur and elemental sulfur in coal are difficult to remove by a common coal washing or gravity separation method, and provides a technical method and a device for removing sulfur in coal by using superheated near-critical water for oxidation.

The device for removing sulfur in coal by using superheated near-critical water through oxidation comprises a process water tank, a preheater, a reactor, an oxygen tank and a cooling pressure reducer, wherein the process water tank is connected with the preheater through a high-pressure water inlet pump, the preheater is connected with the reactor, the reactor is connected with the cooling pressure reducer, the cooling pressure reducer is connected with a gas-liquid separator, the reactor is a cylindrical intermittent reaction kettle, a plurality of layers of supports with wire mesh discs are arranged in the reactor, and the oxygen tank is connected with the reactor through an oxygen pump.

The technical scheme for realizing the aim of the invention is that the method for removing sulfur in coal by using superheated near-critical water through oxidation uses high-temperature high-pressure superheated steam and an oxidant, and the method comprises the following steps: 400-600 ℃, working pressure P: and (3) carrying out desulfurization treatment on the sulfur-containing coal powder under the condition of 10-20 MPa.

The scheme of the invention can be suitable for desulfurization before combustion of various high-sulfur coals and effectively remove sulfur components in various forms.

The technical scheme for realizing the aim of the invention is that the method for removing sulfur in coal by using the oxidation of superheated near-critical water comprises the steps of adding water into a preheater to generate high-temperature high-pressure superheated steam, placing sulfur-containing coal powder on a support with a wire mesh disc in a reactor, introducing the high-temperature high-pressure superheated steam into the reactor, and controlling the internal working temperature T: 400-600 ℃, working pressure P: 10-20MPa, when high-temperature high-pressure superheated steam is introduced into the reactor, oxygen in an oxygen tank is introduced into the reactor through an oxygen pump to react, the mol ratio is adopted between the amount of introduced oxygen and the amount of S in coal powder, the excess oxygen amount is calculated by using sulfate radicals generated by sulfur oxidation products, the peroxide coefficient is 1.2-1.5, the desulfurization time of the coal powder in the reactor is about 1-10 minutes, after the coal desulfurization reaction is finished, the reactor is opened after a reaction system reaches normal temperature and normal pressure through a cooling pressure reducer, and desulfurized coal powder is taken out.

The main principle of the invention is as follows: the pyrite sulfur, organic sulfur and elemental sulfur in the coal can be quickly oxidized in the overheated near-critical water to generate sulfate ions and sulfite ions, and the sulfate ions and the sulfite ions enter a liquid phase to realize the desulfurization of the coal. Especially the removal of organic sulfur in coal is a great advantage of the method of the invention. The organic sulfur in coal usually forms complex molecules with other organic matters in coal in the form of various functional groups, which makes it difficult to remove organic sulfur from coal by conventional washing and gravity separation methods, but the sulfur-containing organic molecules are very easily oxidized rapidly in overheated near-critical water, and the removal efficiency is even higher than that of pyritic sulfur. When the superheated near-critical water working pressure is above 10MPa, the pressure has much less influence on the fluid density thereof, and therefore the influence on the reactant concentration is also smaller, unlike below 10MPa, so that the influence on the reaction rate is smaller by lowering the pressure. Therefore, although the superheated near-critical water fluid slightly reduces the reaction fluid density due to its lower pressure than supercritical water, which has a slight adverse effect on the reaction rate, by taking measures of operating temperature (generally 100-200 ℃ higher than the critical temperature of water), the reaction rate of pressure reduction loss can be compensated. Therefore, the superheated near-critical water with relatively low pressure is used as a medium, and the reaction rate is basically equivalent to that of the supercritical water with relatively high pressure. In addition, near the critical area of water, the diffusion coefficient is increased along with the reduction of pressure and is increased along with the increase of temperature, so that the diffusion coefficient of the overheated near-critical water is higher than that of the supercritical water, the diffusion transmission and the homogeneous reaction of organic matters and oxygen in the overheated near-critical water are facilitated, and the reaction efficiency is improved. Therefore, the peroxide coefficient of the overheating near-critical water oxidation reaction can be smaller than the value of the supercritical water oxidation reaction, the consumption of the oxidant is saved, and the equipment cost and the operation cost of the oxygen pump are reduced.

The method of the invention is suitable for the desulfurization of almost all coal types, is particularly suitable for organic high-sulfur coal which causes the difficulty of conventional coal desulfurization technology before combustion at present, and greatly reduces the pressure of tail end flue gas desulfurization. Meanwhile, the method has high treatment efficiency, short treatment time and no secondary pollution.

Compared with other prior art, the invention has the following advantages:

(1) the method for removing the organic sulfur in the coal has outstanding advantages. Organic matter, oxygen and water tend to be mutually dissolved in a homogeneous phase under the overheat near-critical state of water, and almost no mass transfer resistance exists. The process of the present invention is therefore highly advantageous for the removal of organic sulfur, which is not easily removed by conventional washing and gravity separation. Meanwhile, the method of the invention has good removal effect on sulfur in forms of pyrite sulfur, elemental sulfur and the like in coal.

(2) The method has high desulfurization efficiency, the removal rate of sulfur in coal is generally over 80 percent, and the pressure of flue gas desulfurization after coal combustion can be greatly reduced.

(3) The oxidation desulfurization reaction time in the reactor is short, and the desulfurization oxidation reaction can be completed within only tens of seconds to a few minutes.

(4) Compared with the supercritical water oxidation method, the method disclosed by the invention can reduce the requirements on the materials of the reactor and the preheater, reduce the economic loss caused by corrosion of a reaction vessel due to high pressure, and improve the safety and stability of the system. Has great technical and economic advantages.

Drawings

FIG. 1 is a schematic view of a coal overheating near-critical water oxidation desulfurization device disclosed in the present invention.

In the figure, a process water tank 1, a high-pressure water inlet pump 2, a preheater 3, an external heating sleeve 4, a preheater outlet backpressure valve 5, a reactor 6, a support 7 with a wire mesh disc, an oxygen pump 8, an oxygen tank 9, a raffinate discharge valve 10, a raffinate discharge pipe 11, a reactor outlet valve 12, a temperature and pressure reducing device 13, a water cooling system 14, a backpressure valve 15, a gas-liquid separator 16, a gas phase outlet 17 and a liquid phase outlet 18.

Detailed Description

The embodiment of the present invention will be further described with reference to the following examples, which are the superheated near-critical water oxidation coal desulfurization unit assembled in a laboratory according to the process of the present invention, but do not represent the only embodiment of the present invention.

As shown in figure 1, the device for removing sulfur in coal by using superheated near-critical water through oxidation comprises a process water tank 1, a preheater 3, a reactor 6, an oxygen tank 9 and a cooling pressure reducer 13, wherein the process water tank 1 is connected with the preheater 3 through a high-pressure water inlet pump 2, the preheater 3 is connected with the reactor 6, the reactor 6 is connected with the cooling pressure reducer 13, the cooling pressure reducer 13 is connected with a gas-liquid separator 16, the reactor 6 is a cylindrical intermittent reaction kettle, a plurality of layers of wire mesh disc supports 7 are arranged in the reactor 6, and the oxygen tank 9 is connected with the reactor 6.

Preheater 3 pass through preheater export back pressure valve 5 and connect reactor 6, oxygen jar 9 pass through oxygen pump 8 and reactor 6 and connect, 6 below of reactor be equipped with raffinate drain valve 10, reactor 6 pass through reactor outlet valve 12 and connect cooling pressure reducer 13, cooling pressure reducer 13 pass through back pressure valve 15 and connect vapour and liquid separator 16, vapour and liquid separator 16's upper portion is gas phase outlet 17, and the lower part is liquid phase outlet 18.

By utilizing the device, the method for removing sulfur in coal by utilizing the superheated near-critical water oxidation is realized, the preheater 3 is utilized to add water to generate high-temperature high-pressure superheated steam, sulfur-containing pulverized coal is placed on the wire mesh disc support 7 in the reactor 6, the high-temperature high-pressure superheated steam is introduced into the reactor 6, and the internal working temperature T is controlled: 400-600 ℃, working pressure P: 10-20MPa, introducing oxygen in an oxygen tank 9 into a reactor 6 while introducing high-temperature and high-pressure superheated steam into the reactor 6, adopting a mol ratio of the amount of introduced oxygen to the amount of S in coal powder, calculating the amount of oxygen by using sulfate radicals generated by sulfur oxidation products, wherein the peroxide coefficient is 1.2-1.5, the desulfurization time of the coal powder in the reactor is about 1-10 minutes, and after the coal desulfurization reaction is finished, opening the reactor after a reaction system reaches normal temperature and normal pressure through a temperature and pressure reducer 13, and taking out desulfurized coal powder.

In a particular operating scenario, the preheater 3 is used to produce a continuous effluent stream of superheated steam or superheated near-critical water fluid. The preheater 3 is a cylindrical barrel-shaped structure, and the high-pressure water inlet pump 2 sends water into the preheater from one end of the cylindrical bottom surface of the process water tank 1. The heating jacket 4 coated on the outer wall of the preheater heats water in the preheater, the other end of the cylindrical bottom surface of the preheater is provided with a water outlet which is connected with a reactor 6, and the middle part of the cylindrical bottom surface of the preheater is provided with a preheater outlet back pressure valve 5. The reactor 6 is a cylindrical intermittent reaction kettle, and when the reactor works, the reactor is firstly opened to lay the coal powder on the built-in multilayer wire mesh disc support 7, and then the reactor is sealed. And (3) starting a water inlet pump and a heating sleeve of the preheater, and controlling a back pressure valve at the outlet of the preheater to obtain high-temperature and high-pressure superheated steam in the preheater, wherein the temperature T is generally more than 400 ℃, and the pressure P is about 5-10 MPa. Superheated steam is passed into the reactor to heat the coal fines to a predetermined temperature, typically above 400 ℃. And then closing a back pressure valve at the outlet of the preheater to increase the pressure and the temperature of the superheated steam in the preheater to reach the preset working temperature and working pressure, so that the superheated steam becomes a superheated near-critical water fluid. Working temperature T >400 ℃, working pressure P: 10 to 20 MPa. And opening a back pressure valve 5 at the outlet of the preheater to introduce superheated near-critical water fluid into the reactor to prepare for the superheated near-critical water oxidation desulfurization reaction. The oxidant can be selected from hydrogen peroxide or oxygen, the hydrogen peroxide can be stirred with the pulverized coal according to a certain proportion when the pulverized coal is placed in the reactor, and the oxygen can be fed into the reactor by a high-pressure oxygen pump 8 at the same time when the superheated near-critical water fluid is fed into the reactor. The amount of the oxidant is converted by oxygen, and the proportion of the introduced oxygen to the S in the coal powder adopts a mol ratio. The over-oxygen amount is calculated by using sulfate radicals generated by sulfur oxidation products, and the peroxide coefficient is 1.2-1.5. The superheated near-critical water fluid continuously flows through the main body equipment in sequence, and is cooled in the temperature-reducing pressure reducer 13 through an external cooler. A back pressure valve 15 is arranged on a water outlet pipe at the tail end of the temperature reduction pressure reducer, the pressure in the control system is stabilized at the working pressure, the continuous operation of the system is ensured when the system is started, and the pressure can be rapidly released after the desulfurization reaction is finished. The fluid flows out of the back pressure valve and then enters a gas-liquid separator 16 to separate gas from liquid, the gas is discharged from a gas phase outlet 17, the liquid is discharged from a liquid phase outlet 18, and sulfur in the coal is converted into sulfate radicals and sulfite radicals which are discharged along with the liquid, so that the desulfurization of the coal is realized.

The desulfurization time of coal in the reactor is about 1-10 minutes, after the coal desulfurization reaction is finished, the inlet high-pressure plunger pump 2 of the preheater and the outlet backpressure valve 5 of the preheater are closed, the high-pressure oxygen pump 8 is closed, the pressure is relieved through the backpressure valve 15, the reactor is opened after the reaction system reaches normal temperature and normal pressure, and desulfurized coal powder is taken out. If there is residual liquid in the reactor, the residual liquid discharge valve 10 can be opened to discharge the residual liquid from the residual liquid discharge pipe 11 at the bottom of the reactor.

The core equipment preheater 3 and the reactor 6 of the device are both cylindrical and are made of nickel-based corrosion-resistant steel NS 336. The cylindrical part of the shell of the preheater 3 is 1600mm in height and 50mm in inner diameter, and a hemispherical seal head is adopted. The reactor 6 is a batch type reaction kettle with the height of 500mm and the inner diameter of 100 mm. The reactor is provided with a built-in 5-layer corrosion-resistant stainless steel bracket, and a stainless steel disc-shaped wire mesh is placed on the bracket and used for containing pulverized coal. The heating jacket 4 outside the preheater 3 adopts far infrared heating. WRNK-331 armored thermocouples are arranged in the preheater, the reactor and the temperature reduction and pressure reduction device to measure the temperature. The water inlet of the preheater 3 is pumped by a high-pressure plunger metering pump, the rated full load flow of the pump is 15L/h, the rated pressure is 28MPa, the two pumps are used, one is used, and the other can be started simultaneously. The oxidant is oxygen, the oxygen pump 8 is pumped by a high-pressure diaphragm compressor, and the rated volume flow is 3Nm³H is used as the reference value. The oxygen flow was measured by a DMF-1 Coriolis mass flow meter. The back pressure valves of the outlet pipeline of the preheater and the outlet pipeline of the cooling pressure reducer are both 50MPa high-pressure stainless steel double-ferrule back pressure valves, the precision is +/-1%, and manual mechanical control is performed. The temperature reduction and pressure reduction device 13 is made of a high-pressure-resistant corrosion-resistant nickel-based stainless steel pipe with the pipe diameter of 10mm, and is cooled by means of a water cooling system 14 through heat exchange with process water. The heated process water is introduced into the process water tank 1 for standby. The gas-liquid separator 16 adopts a stainless steel centrifugal structure, and can effectively separate gas from liquid.

The device of the invention is started according to the following operation procedure to realize the aim of coal desulfurization. Firstly, opening the reactor 6, placing pulverized coal which is smashed in advance on a net disk of a pulverized coal support 7 in the reactor, covering a reactor cover, and fastening the reactor cover by using bolts after sealing. Closing a back pressure valve 5 at the outlet of the preheater, starting a water inlet pump 2 of the preheater to feed water with the volume of about 40 percent of the volume of the preheater from a process water tank 1, starting an external heating jacket 4 for heating, and simultaneously controlling the back pressure valve 5 at the outlet of the preheater to obtain high-temperature high-pressure superheated steam in the preheater, wherein the general temperature T is more than 400 ℃, and the pressure P is about 5-10 MPa. Superheated steam is passed into the reactor to heat the coal fines to a predetermined temperature, typically above 400 ℃. And then closing a back pressure valve at the outlet of the preheater, and increasing the pressure and temperature of the superheated steam in the preheater to reach the rated working temperature (400-600 ℃) and the working pressure (10-20 MPa) so that the superheated steam becomes a superheated near-critical water fluid. And then controlling the water inflow of a water inlet high-pressure plunger pump of the preheater, starting and stopping of an external heater of the preheater and stopping of an outlet back pressure valve of the preheater to stabilize the working pressure and temperature in the preheater. Opening a back pressure valve 5 at the outlet of the preheater to introduce overheated near-critical water fluid into the reactor, and simultaneously opening an oxygen pump 8 to introduce oxygen according to a preset peroxide coefficient (1.2-1.5). The coal powder in the reactor immediately undergoes an overheating near-critical water oxidation desulfurization reaction, and the reaction time is generally about 1-5 minutes. While the oxidation desulfurization reaction of the pulverized coal water in the reactor, the overheated near-critical fluid flowing through the reactor continuously flows through the temperature reduction pressure reducer 13, is decompressed and discharged through the backpressure valve 15 after temperature reduction, enters the gas-liquid separator 16 to separate gas from liquid, gas is discharged from the gas-phase outlet 17, liquid is discharged from the liquid-phase outlet 18, and sulfur in the coal is converted into sulfate radicals and sulfite radicals to be discharged along with the liquid. And after the coal desulfurization reaction is finished, stopping the high-pressure plunger pump 2 for feeding water into the preheater and the back pressure valve 5 at the outlet pipe of the high-pressure plunger pump, stopping the oxygen pump 8 of the reactor, releasing pressure through the back pressure valve 15, opening the reactor after the reaction system reaches normal temperature and normal pressure, and taking out desulfurized coal powder.

Example 1:

the coal sample is Taiyuan coal with dry ash-free combustible sulfur content of 1%.

Taking 1000g of a coal sample, uniformly crushing the coal sample to have an average particle size of about 0.5-1 mm, and putting the coal sample into a reactor 6. The preheater 3 generates high-temperature superheated steam, and the high-temperature superheated steam is introduced into the reactor to heat the pulverized coal to 420 ℃. Then the water in the preheater is heated to 480 ℃ by an external heating jacket 4, the pressure is increased to 10MPa, the fluid in the overheat near-critical state enters a reactor through a back pressure valve 5, and then oxygen is introduced into the reactor, and the peroxide coefficient is controlled to be 1.3. Reacting for 5 minutes, introducing gas discharged from a gas-phase outlet of the gas-liquid separator into a solvent bottle 1 filled with sodium hydroxide solution during the reaction, and collecting liquid discharged from a liquid-phase outlet to flow into a clean solvent bottle 2. And (5) stopping the system after the reaction is finished, and reducing the temperature and releasing the pressure. And opening the reactor after the reaction system reaches normal temperature and normal pressure, and taking out the desulfurized pulverized coal. The concentrations of sulfate ions and sulfite ions in the solutions of the solvent bottle 1 and the solvent bottle 2 are respectively detected. And measuring sulfite ions in the solution by using an iodine-starch spectrophotometry, and measuring sulfate ions in the solution by using a barium chromate colorimetric method. No sulfate and sulfite ions were detected in the solution in solvent bottle 1 from which the gas phase was collected. Sulfate and sulfite ions were detected in the solvent bottle 2 in which the liquid phase solution was collected, and the mass of sulfur in the liquid phase solution was calculated to be about 9.3g based on the measured value. The mass of sulfur in the pulverized coal after desulfurization in the reactor was analyzed and determined to be about 0.7 g. The desulfurization rate was calculated to be about 93%.

Example 2:

the coal sample is selected from big same raw coal, and the content of dry ash-free combustible sulfur is 1.1 percent.

The operation flow and the method are the same as those of the embodiment example 1. The main parameter differences are as follows. The coal sample is 800g, and the average particle size of the coal sample is about 1-2 mm after uniform grinding. High-temperature superheated steam is firstly introduced to heat the coal powder to 420 ℃. The water in the preheater is heated to 480 ℃, the pressure is maintained at 15MPa, oxygen is introduced into the reactor, the peroxide coefficient is 1.2, and the reaction lasts for 4 minutes.

No sulfate and sulfite ions were detected in the solution in solvent bottle 1 from which the gas phase was collected. Sulfate and sulfite ions are detected in the solvent bottle 2 for collecting the liquid phase solution, and the mass of sulfur in the liquid phase solution is calculated to be about 8g according to the measured value. The mass of sulfur in the pulverized coal after the desulfurization reaction in the reactor was analyzed and determined to be about 0.8 g. The desulfurization rate was calculated to be about 91%.

Example 3:

the coal sample is long-term anthracite, and the content of dry ash-free combustible sulfur is 0.8 percent.

The operation flow and the method are the same as those of the embodiment example 1. The main parameter differences are as follows. 1300g of coal sample, and the average particle size of the coal sample is about 1-2 mm after uniform grinding. Introducing high-temperature steam to heat the coal powder to 420 ℃. The water in the preheater is heated to 520 ℃, the pressure is maintained at 20MPa, oxygen is introduced into the reactor, the peroxide coefficient is 1.5, and the reaction lasts 8 minutes.

No sulfate and sulfite ions were detected in the solution in solvent bottle 1 from which the gas phase was collected. Sulfate and sulfite ions were detected in the solvent bottle 2 in which the liquid phase solution was collected, and the sulfur mass in the liquid phase solution was calculated to be about 9.8g based on the measured value. The mass of sulfur in the pulverized coal after the desulfurization reaction in the reactor was analyzed and determined to be about 0.6 g. The desulfurization rate was calculated to be about 94%.