A system and method for preparing clean coal based on thermal storage oxidation of low-concentration gas

Abstract

The present invention discloses a system and method for preparing clean coal based on low-concentration gas thermal storage oxidation, including a gas delivery pipeline, a thermal storage oxidation device, a high-temperature thermal storage chamber, a material transportation track, a retort chamber, a cooling chamber, a transfer chamber, a tail gas reuse pipeline, a one-way door, a pressure sensor, an electric control regulating valve, a raw gas output pipeline, a precipitation separation device, a desulfurization device, and a gas delivery pipeline; low-concentration gas enters the thermal storage oxidation device through the gas delivery pipeline; the high-temperature hot gas generated by the thermal storage oxidation device enters the high-temperature thermal storage chamber, and the gas passing through the high-temperature thermal storage chamber enters the cooling chamber and the transfer chamber respectively through the tail gas reuse pipeline; the raw gas output pipeline is directly connected to the precipitation separation device, and a desulfurization device is arranged downstream of the precipitation separation device, and the desulfurization device is connected to the gas delivery pipeline through the gas delivery pipeline. The coal slime or low-rank coal treated by the system has lower volatile matter and sulfur content, and can be directly used for civilian combustion.

Description

Technical Field

[0001] The present invention relates to a clean coal preparation technology, in particular to a system and method for preparing clean coal based on low-concentration gas thermal storage oxidation. Background Art

[0002] In the current energy structure, oil and natural gas resources are scarce, while coal reserves are relatively abundant, accounting for nearly 70% of the energy structure and occupying a dominant position. At present, the proven coal reserves are 1020 billion tons, more than 55% of which are low-grade coal with a low degree of coalification, and the volatile matter contained in them is equivalent to 100 billion tons of oil and gas resources.

[0003] However, due to the characteristics of low-rank coal, such as high water content, high volatile content and low calorific value, the existing technology cannot fully utilize its resource value, resulting in a huge waste of coal resources. At the same time, the ultra-low sulfur coal with a content of less than 0.5% in coal resources is very limited, and large-scale mining and widespread use of ultra-low sulfur coal are obviously unrealistic. Therefore, it is urgent to provide a method for converting these low-rank coals and / or high-sulfur coals into clean coal. Summary of the invention

[0004] The object of the present invention is to provide a system and method for preparing clean coal based on thermal storage oxidation of low-concentration gas.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The system for preparing clean coal based on low-concentration gas thermal storage oxidation of the present invention, the clean coal production line includes a retort chamber, a cooling chamber and a transfer chamber arranged in sequence from the low-rank coal inlet to the clean coal outlet, a high-temperature thermal storage chamber is arranged around the retort chamber, and a material transportation track is arranged in the retort chamber, the cooling chamber and the transfer chamber from the low-rank coal inlet to the clean coal outlet, and the material transportation track is equipped with a traction winch;

[0007] The front end of the retort chamber is isolated from the air by a one-way door, the front end of the transfer chamber is isolated from the cooling chamber by a one-way door, and the rear end of the transfer chamber is isolated from the air by a one-way door;

[0008] A thermal storage oxidation device is arranged on a gas transport pipeline for transporting low-concentration gas, and a high-temperature hot gas outlet pipeline of the thermal storage oxidation device is connected to the high-temperature thermal storage chamber;

[0009] The high-temperature heat storage chamber is connected to an exhaust gas treatment device and an exhaust gas reuse pipeline, the exhaust gas reuse pipeline is connected to the cooling chamber and the transfer chamber respectively, and an electric control regulating valve is provided on the inlet pipeline of the exhaust gas treatment device;

[0010] The outlet of the distillation chamber is connected to the precipitation separation equipment through a crude gas output pipeline, on which a pressure sensor and an electrically controlled regulating valve are provided, the outlet pipeline of the precipitation separation equipment is connected to the desulfurization device, and the gas delivery pipeline at the outlet of the desulfurization device is connected to the gas delivery pipeline.

[0011] The above-mentioned system for preparing clean coal by thermal storage oxidation of low-concentration gas implements a method for preparing clean coal by thermal storage oxidation of low-concentration gas, comprising the steps of:

[0012] The low-concentration gas enters the thermal storage oxidation device through the gas delivery pipeline;

[0013] The high-temperature hot air generated by the thermal storage oxidation device is controlled by a variable frequency fan in front of the thermal storage oxidation device to enter the high-temperature thermal storage chamber;

[0014] The gas passing through the high-temperature heat storage chamber enters the cooling chamber and the transfer chamber respectively through the tail gas reuse pipeline;

[0015] The crude coal gas output pipeline of the distillation chamber is connected to the precipitation separation device. After the tar substances produced by pyrolysis are collected by the precipitation separation device, they are desulfurized by the desulfurization device downstream thereof and enter the gas transmission pipeline through the coal gas transmission pipeline.

[0016] It can be seen from the technical solution provided by the present invention as described above that the system and method for preparing clean coal based on thermal storage oxidation of low-concentration gas provided in the embodiments of the present invention effectively utilize the high-temperature hot gas of the thermal storage oxidation device, reduce the energy loss of the thermal storage oxidation device, and obtain a large amount of coal gas and tar through the quality improvement process of low-rank coal. The coal gas generated by the system can enter the thermal storage oxidation device or other devices again for utilization, and the operation is simple and the safety factor is high. The obtained product can be directly used for civil combustion, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a system for preparing clean coal based on thermal storage oxidation of low-concentration gas provided in an embodiment of the present invention.

[0018] In the figure:

[0019] 1-gas transmission pipeline; 2-thermal storage oxidation device; 3-high-temperature hot gas generated after thermal storage oxidation; 4-high-temperature thermal storage chamber; 5-material transportation track; 6-drying chamber; 7-cooling chamber; 8-transfer chamber; 9-exhaust gas reuse pipeline; 10, 11, 12-one-way doors; 13-electrically controlled regulating valve; 14-exhaust gas treatment device; 15-air pressure sensor; 16-electrically controlled regulating valve; 17-raw coal gas output pipeline; 18-precipitation and separation equipment; 19-desulfurization device; 20-gas transmission pipeline. DETAILED DESCRIPTION

[0020] The embodiments of the present invention will be described in further detail below. The contents not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

[0021] The system and method for preparing clean coal based on thermal storage oxidation of low-concentration gas of the present invention has the following preferred embodiments:

[0022] The clean coal production line includes a retort chamber, a cooling chamber and a transfer chamber arranged in sequence from the low-rank coal inlet to the clean coal outlet, a high-temperature heat storage chamber is arranged around the retort chamber, and a material transportation track is arranged in the retort chamber, the cooling chamber and the transfer chamber from the low-rank coal inlet to the clean coal outlet, and the material transportation track is equipped with a traction winch;

[0023] The front end of the retort chamber is isolated from the air by a one-way door, the front end of the transfer chamber is isolated from the cooling chamber by a one-way door, and the rear end of the transfer chamber is isolated from the air by a one-way door;

[0024] A thermal storage oxidation device is arranged on a gas transport pipeline for transporting low-concentration gas, and a high-temperature hot gas outlet pipeline of the thermal storage oxidation device is connected to the high-temperature thermal storage chamber;

[0025] The high-temperature heat storage chamber is connected to an exhaust gas treatment device and an exhaust gas reuse pipeline, the exhaust gas reuse pipeline is connected to the cooling chamber and the transfer chamber respectively, and an electric control regulating valve is provided on the inlet pipeline of the exhaust gas treatment device;

[0026] The outlet of the distillation chamber is connected to the precipitation separation equipment through a crude gas output pipeline, on which a pressure sensor and an electrically controlled regulating valve are provided, the outlet pipeline of the precipitation separation equipment is connected to the desulfurization device, and the gas delivery pipeline at the outlet of the desulfurization device is connected to the gas delivery pipeline.

[0027] The interior of the dry distillation chamber is made of heat storage ceramic material, and the high-temperature heat storage chamber is provided with a variable frequency fan in front of a heat storage oxidation device.

[0028] The above-mentioned system for preparing clean coal by thermal storage oxidation of low-concentration gas implements a method for preparing clean coal by thermal storage oxidation of low-concentration gas, comprising the steps of:

[0029] The low-concentration gas enters the thermal storage oxidation device through the gas delivery pipeline;

[0030] The high-temperature hot air generated by the thermal storage oxidation device is controlled by a variable frequency fan in front of the thermal storage oxidation device to enter the high-temperature thermal storage chamber;

[0031] The gas passing through the high-temperature heat storage chamber enters the cooling chamber and the transfer chamber respectively through the tail gas reuse pipeline;

[0032] The crude coal gas output pipeline of the distillation chamber is connected to the precipitation separation device. After the tar substances produced by pyrolysis are collected by the precipitation separation device, they are desulfurized by the desulfurization device downstream thereof and enter the gas transmission pipeline through the coal gas transmission pipeline.

[0033] The air pressure in the retort chamber is monitored by the air pressure sensor, and the air pressure in the retort chamber is controlled by the electric control regulating valve;

[0034] The gas concentration in the raw gas output pipeline is adjusted by the tail gas volume of the tail gas reuse pipeline, and the tail gas volume of the tail gas reuse pipeline is controlled by an electrically controlled regulating valve arranged at the front end of the tail gas treatment device.

[0035] The high-temperature hot gas generated after the thermal storage oxidation has a temperature of 900-1000 degrees Celsius.

[0036] The low-rank coal is ground to obtain low-rank coal powder with a particle size of less than 100 microns; the residence time of the low-rank coal powder in the dry distillation chamber is 0.5-2 hours.

[0037] The combustible gas entering the thermal oxidizer is diluted by tail gas, and the coal gas and the extracted gas are mixed into the thermal oxidizer to ensure that the concentration of the mixed combustible gas is less than 1.25%.

[0038] By recycling the tail gas, the oxygen concentration in the clean coal production line is controlled to be less than 4%, tending to 0, ensuring that the coal and gas are in a non-combustible and non-explosive environment.

[0039] Compared with the prior art, the advantages of the present invention are:

[0040] This method effectively utilizes the high-temperature hot air of the thermal storage oxidation device, reduces the energy loss of the thermal storage oxidation device, and can obtain a large amount of coal gas and tar through the quality improvement process of low-rank coal. The coal gas generated by the system can enter the thermal storage oxidation device or other settings for utilization again. The method is simple to operate and has a high safety factor. The obtained products can be directly used for civil combustion, etc. Specific embodiment:

[0042] Attached Figure 1 The schematic diagram of the preparation of clean coal based on thermal oxidation of low-concentration gas provided in the embodiment of the present invention is shown in the attached figure. Figure 1 As shown, the interior is made of thermal storage ceramic material. The high-temperature hot gas generated after thermal storage oxidation is 900-1000 degrees Celsius. The low-rank coal is ground to obtain a low-rank coal powder with a particle size of less than 100 microns. The low-rank coal powder is transported into the retorting chamber through the material transport track of the one-way door; the low-rank coal powder stays in the retorting chamber for 0.5-2 hours; the low-rank coal powder enters the cooling chamber from the material transport track and enters the transfer chamber through the one-way door, and is finally taken out through the one-way door.

[0043] The gas transmission pipeline needs to be combined with other inventive means to control the oxygen concentration in the gas; the high-temperature hot gas generated after thermal storage oxidation is controlled by the variable frequency fan in front of the thermal storage oxidation device and enters the high-temperature heat storage chamber through the heat-resistant pipeline. After the gas passes through the high-temperature heat storage chamber to heat the low-rank coal powder in the distillation chamber, the temperature is reduced and the gas is connected to the cooling chamber and the transfer chamber respectively through the tail gas reuse pipeline; the amount of tail gas entering the cooling chamber is controlled by the electric control regulating valve arranged at the front end of the tail gas treatment device, and the gas enters the distillation chamber and enters the raw coal gas output pipeline with the raw coal gas after coal pyrolysis; the gas pressure difference on both sides of the coal inlet one-way door must always be kept at zero to avoid outside air from entering and coal gas overflowing from the distillation chamber; the pressure generated by the tail gas reuse is used to achieve equal pressure inside and outside the distillation chamber to ensure that air outside the system cannot enter the system and the coal gas in the system will not escape to the outside of the system; the air pressure sensor monitors the air pressure in the distillation chamber in real time, and the two electric control regulating valves control the air pressure in the distillation chamber to be greater than the atmospheric pressure; the data is continuously monitored by the sensor and programmed and controlled by the programmable controller. By recycling the tail gas, the oxygen concentration in the clean coal production line is controlled to be less than 4%, tending to 0, ensuring that the coal and gas are in a non-combustible and non-explosive environment.

[0044] The raw coal gas entering the raw coal gas output pipeline enters the precipitation separation equipment and collects tar and other substances produced by pyrolysis; the coal gas after tar precipitation is desulfurized by the desulfurization device and connected to the gas transmission pipeline through the coal gas transmission pipeline; the exhaust gas is used to dilute the combustible gas entering the thermal storage oxidation device, and the coal gas and the extracted gas are mixed to enter the thermal storage oxidation device to ensure that the concentration of the mixed combustible gas is less than 1.25%.

[0045] The product obtained by this method can be directly used for civil combustion, etc.

[0046] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention 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 invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing clean coal based on thermal storage oxidation of low-concentration gas, characterized in that: The method is implemented by using a system based on thermal storage oxidation of low-concentration gas to prepare clean coal; The system comprises a retort chamber (6), a cooling chamber (7) and a transfer chamber (8) which are arranged in sequence from a low-rank coal inlet to a clean coal outlet, a high-temperature heat storage chamber (4) is arranged around the retort chamber (6), a material transport track (5) is arranged in the retort chamber (6), the cooling chamber (7) and the transfer chamber (8) from the low-rank coal inlet to the clean coal outlet, and the material transport track (5) is equipped with a traction winch; The front end of the retort chamber (6) is isolated from the air by a one-way door (10), the front end of the transfer chamber (8) is isolated from the cooling chamber (7) by a one-way door (11), and the rear end of the transfer chamber (8) is isolated from the air by a one-way door (12); A thermal storage oxidation device (2) is provided on a gas transport pipeline (1) for transporting low-concentration gas, and a high-temperature hot gas (3) outlet pipeline of the thermal storage oxidation device (2) is connected to the high-temperature thermal storage chamber (4); The high-temperature heat storage chamber (4) is connected to an exhaust gas treatment device (14) and an exhaust gas reuse pipeline (9), the exhaust gas reuse pipeline (9) is connected to the cooling chamber (7) and the transfer chamber (8) respectively, and an electric control regulating valve (13) is provided on the inlet pipeline of the exhaust gas treatment device (14); The outlet of the dry distillation chamber (6) is connected to a precipitation separation device (18) via a crude gas output pipeline (17), the crude gas output pipeline (17) being provided with a gas pressure sensor (15) and an electrically controlled regulating valve (16), the outlet pipeline of the precipitation separation device (18) being connected to a desulfurization device (19), and the gas delivery pipeline (20) at the outlet of the desulfurization device (19) being connected to the gas delivery pipeline (1); The system implements a method for preparing clean coal by thermal storage oxidation of low-concentration gas, comprising the steps of: The low-concentration gas enters the thermal storage oxidation device (2) through the gas delivery pipeline (1); The high-temperature hot air (3) generated by the thermal storage oxidation device (2) is controlled by a variable frequency fan in front of the thermal storage oxidation device to enter the high-temperature thermal storage chamber (4); The gas passing through the high-temperature heat storage chamber (4) enters the cooling chamber (7) and the transfer chamber (8) respectively through the tail gas reuse pipeline (9); The crude coal gas output pipeline (17) of the dry distillation chamber (6) is connected to a precipitation separation device (18). After the tar substances produced by pyrolysis are collected by the precipitation separation device (18), they are desulfurized by a desulfurization device (19) downstream thereof and enter the gas delivery pipeline (1) through a coal gas delivery pipeline (20).

2. The method for preparing clean coal based on thermal storage oxidation of low-concentration gas according to claim 1, characterized in that: The interior of the dry distillation chamber (6) is made of heat storage ceramic material, and the high-temperature heat storage chamber (4) is provided with a variable frequency fan in front of a heat storage oxidation device.

3. The method for preparing clean coal based on thermal storage oxidation of low-concentration gas according to claim 1 or 2, characterized in that: The air pressure in the distillation chamber (6) is monitored by the air pressure sensor (15), and the air pressure in the distillation chamber (6) is controlled by the electrically controlled regulating valve (16); The gas concentration in the raw gas output pipeline (17) is adjusted by the exhaust gas volume of the exhaust gas reuse pipeline (9), and the exhaust gas volume of the exhaust gas reuse pipeline (9) is controlled by an electrically controlled regulating valve (13) arranged at the front end of the exhaust gas treatment device (14).

4. The method for preparing clean coal based on thermal storage oxidation of low-concentration gas according to claim 3 is characterized in that: The high-temperature hot gas (3) generated after the thermal storage oxidation has a temperature of 900-1000 degrees Celsius.

5. The method for preparing clean coal based on thermal storage oxidation of low-concentration gas according to claim 4, characterized in that: The low-rank coal is ground to obtain a low-rank coal powder with a particle size of less than 100 microns; the residence time of the low-rank coal powder in the dry distillation chamber (6) is 0.5-2 hours.

6. The method for preparing clean coal based on thermal storage oxidation of low-concentration gas according to claim 5, characterized in that: The combustible gas entering the thermal storage oxidation device (2) is diluted using tail gas, and the coal gas and the extracted gas are mixed and enter the thermal storage oxidation device (2) to ensure that the concentration of the mixed combustible gas is less than 1.25%.

7. The method for preparing clean coal based on thermal storage oxidation of low-concentration gas according to claim 6, characterized in that: By recycling the exhaust gas, the oxygen concentration in the clean coal production line is controlled to be less than 4%, tending towards 0, ensuring that the coal and gas are in a non-combustible and non-explosive environment.

Images