A lump coal pyrolysis process

Abstract

The present invention relates to a lump coal pyrolysis process, the process comprising: a solid heat carrier after fluidized heating heats a heat carrier gas, and the heated gas is used as a gas heat carrier to pyrolyze the raw lump coal. The present invention provides a new lump coal pyrolysis process coupled with fluidized heating, wherein the pyrolysis gas is heated by a solid heat carrier coupled with circulating fluidization, and the heated high-temperature gas is used as a gas heat carrier to pyrolyze the raw coal. Since the energy of the high-temperature gas comes from the heat exchange of the solid heat carrier, the gas used as a carrier gas does not contain gases such as N2, CO and CO2 generated by air combustion, so the calorific value of the gas produced during the pyrolysis process is increased and the quality is greatly improved, which will promote the entire pyrolysis process to be more efficient and more environmentally friendly. At the same time, the process gas has the advantages of high calorific value, less sewage, and full energy utilization, and the entire pyrolysis process is more efficient and more environmentally friendly.

Description

Technical Field

[0001] The invention relates to the field of coal pyrolysis, and in particular to a lump coal pyrolysis process. Background Art

[0002] At present, my country has abundant reserves of low-rank coal, accounting for 55% of the total proven coal reserves. With the expansion of the application scope of low-rank coal and the increase in the rate of mechanical coal mining, the coal pyrolysis technology with low-rank coal as the main object has gradually developed into a graded pyrolysis technology divided by coal particle size. Among them, the technologies using lump coal as raw materials mainly include vertical blue charcoal furnace, rotary kiln, Guofu furnace technology, etc. After continuous improvement, the production efficiency of the technology using lump coal as raw material has been continuously improved, and the current application scale has reached tens of millions of tons per year. The most representative of lump coal pyrolysis technology is the blue charcoal production process.

[0003] Semi-coke originated in Shenfu, northern Shaanxi and surrounding areas. It is an important raw material for the production of calcium carbide and iron-magnesium alloys. It is also used in blast furnace ironmaking and home heating. The production and application of semi-coke is of great significance for building a local industry chain and promoting the clean and efficient use of coal.

[0004] The production process of semi-coke is mainly based on the external combustion and internal heating vertical carbonization technology, which is developed from the early Wood furnace and Lurgi three-stage furnace. In the 1990s, Shenfu coalfield was developed, and Shenmu County introduced and applied vertical carbonization technology to carry out large-scale semi-coke production. After years of continuous improvement, the external combustion and internal heating vertical carbonization technology has gradually matured. Due to its simple process, stable operation and investment savings, the vertical carbonization technology has been widely used. For example, CN106701129A discloses a lump coal heat storage pyrolysis reaction system and method. The system adopts an internal external heating type, and the pyrolysis gas has a high calorific value, which is conducive to the subsequent utilization of the pyrolysis gas, and can realize the pyrolysis treatment of low-rank coal, overcome the problem of fragility during the pyrolysis process of low-rank coal, and can process long flame coal and lignite. CN105062526A discloses a coal pyrolysis gasification multi-generation system and its pyrolysis gasification method, which has low energy consumption, good environmental performance, good coal adaptability, convenient equipment processing and manufacturing, eliminates safety hazards, and improves the effect.

[0005] Although the external combustion internal heating vertical carbonization furnace technology is widely used, there are still many problems in the production process of blue carbonization due to its simple and extensive production process. The main problems of vertical carbonization technology are high inert gas content in pyrolysis gas and low calorific value of gas; large pyrolysis wastewater output, many types of pollutants, and difficult to treat; blue carbonization cooling generally uses water quenching, which has low thermal efficiency and poor product quality; low tar yield and high content of heavy components, which is not conducive to subsequent processing. Summary of the invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a lump coal pyrolysis process. In the process provided by the present invention, since the high-temperature coal gas energy comes from the heat exchange of the solid heat carrier, the coal gas used as the carrier gas does not contain gases such as N2, CO and CO2 produced by air combustion. Therefore, the calorific value of the coal gas produced in the pyrolysis process is increased and the quality is greatly improved, which will promote the entire pyrolysis process to be more efficient and more environmentally friendly.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The present invention provides a lump coal pyrolysis process, which comprises: a solid heat carrier after fluidization heating heats a heat carrier coal gas, and the heated coal gas is used as a gas heat carrier to pyrolyze a raw material lump coal.

[0009] The present invention provides a new lump coal pyrolysis process coupled with fluidized heating, in which pyrolysis coal gas is heated by a solid heat carrier coupled with circulating fluidization, and the heated high-temperature coal gas is used as a gas heat carrier to pyrolyze the raw coal. Since the energy of the high-temperature coal gas comes from the heat exchange of the solid heat carrier, the coal gas used as the carrier gas does not contain gases such as N2, CO and CO2 generated by air combustion, so the calorific value of the coal gas produced during the pyrolysis process is increased and the quality is greatly improved, which will promote the entire pyrolysis process to be more efficient and more environmentally friendly. At the same time, the process coal gas has the advantages of high calorific value, less sewage, and full energy utilization, and the entire pyrolysis process is more efficient and more environmentally friendly.

[0010] As a preferred technical solution of the present invention, the raw lump coal is low-grade lump coal.

[0011] Preferably, the particle size of the raw material lump coal is 6-80 mm, for example, it can be 6 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm or 80 mm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0012] Preferably, the raw material lump coal is dried before pyrolysis.

[0013] Preferably, the temperature of the drying gas in the drying process is 100-300°C, for example, it can be 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C or 300°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0014] Preferably, the wet flue gas formed in the drying process is subjected to dust removal and condensation to recover condensed water.

[0015] Preferably, the temperature of the wet flue gas is 50-150°C, for example, it can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0016] Preferably, the heat source for the drying process is waste heat recovered during the gas heating process.

[0017] In the present invention, water in wet flue gas is recovered to reduce the generation of difficult-to-treat pyrolysis wastewater in the pyrolysis system.

[0018] As a preferred technical solution of the present invention, the pyrolysis is countercurrent pyrolysis.

[0019] Preferably, the pyrolysis produces semi-coke and oil gas.

[0020] Preferably, the temperature of the oil and gas is 250-350°C, for example, it can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C or 350°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0021] Preferably, a heat recovery operation is also provided in the pyrolysis process.

[0022] As a preferred technical solution of the present invention, the oil and gas are introduced into a distillation tower for fractionation after dust removal.

[0023] Preferably, the dust removal equipment includes a gas-solid separator.

[0024] Preferably, the oil and gas are introduced through the lower part of the distillation tower.

[0025] Preferably, after entering the distillation tower, the oil and gas are washed with coal tar, cooled and heat-exchanged to 100-120°C, for example, it can be 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C or 120°C, but is not limited to the listed values, and other values ​​not listed in this range are also applicable.

[0026] Preferably, the coal tar used for washing is extracted from the bottom of the distillation tower, and after cooling and dust removal, 50-80% of it is returned to the bottom of the distillation tower for cyclic washing, and the remaining part enters the flash tower after heating, the coal tar at the top of the flash tower is returned before the dust removal operation, and the coal tar at the bottom of the flash tower is output as a product.

[0027] Preferably, the oil and gas are separated at the top of the fractionation tower after cooling.

[0028] Preferably, the cooled oil and gas are separated to obtain light oil, water and coal gas.

[0029] Preferably, the light oil is returned to the fractionation tower.

[0030] Preferably, 80-95% of the coal gas is returned as heat carrier gas, and the rest is used as product, for example, it can be 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94% or 95, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0031] Preferably, the fractionation also includes extracting phenol-containing light oil from the 170-210°C section of the distillation tower, for example, it can be 170°C, 180°C, 190°C, 200°C or 210°C, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0032] Preferably, the phenol-containing light oil is subjected to a phenol extraction operation to obtain dephenolized light oil and crude phenol.

[0033] Preferably, the dephenolized light oil is returned to the fractionation tower.

[0034] Preferably, the phenol content in the water is less than 1500 ppm, and the oil content is less than 800 ppm.

[0035] In the present invention, the content of phenol in the water is less than 1500ppm, for example, it can be 1500ppm, 1480ppm, 1460ppm, 1440ppm, 1420ppm, 1400ppm, 1380ppm, 1360ppm, 1340ppm or 1320ppm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0036] In the present invention, the oil content in the water is less than 800 ppm, for example, it can be 800 ppm, 780 ppm, 760 ppm, 740 ppm, 720 ppm, 700 ppm, 780 ppm, 760 ppm, 740 ppm, 720 ppm or 700 ppm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0037] As a preferred technical solution of the present invention, the semi-coke obtained by pyrolysis is sent to a coke plant after three-stage cooling treatment.

[0038] Preferably, the three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling performed in sequence.

[0039] Preferably, the pressure of the steam in the heat exchange tube after heat exchange in the water-cooled wall tube cooling is 0.5-1MPa, for example, it can be 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa or 1MPa, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0040] Preferably, the temperature of the semi-coke after cooling of the water-cooled wall tubes is 350-450°C, for example, it can be 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C or 450°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0041] Preferably, a cold gas injection port is provided at the cooling lower portion of the water-cooled wall tube, and the cold gas is heated by heat exchange with the semi-coke and then enters the pyrolysis section to mix with the heat carrier gas.

[0042] Preferably, the cooling carrier in the circulating convection cooling is an inert gas.

[0043] Preferably, the temperature of the semi-coke after the circulating convection cooling is 100-180°C, for example, it can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0044] Preferably, the water spray cooling method is water mist cooling.

[0045] Preferably, the temperature of the semi-coke after water spray cooling is less than 70°C, for example, it can be 70°C, 65°C, 60°C, 55°C, 50°C, 45°C or 40°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0046] As a preferred technical solution of the present invention, the heat carrier gas is pressurized before being heated.

[0047] Preferably, the solid heat carrier heats the heat carrier gas in a mixing heating tube and / or a fluidized heater.

[0048] Preferably, the temperature of the heated coal gas is 600-800°C, for example, it may be 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, 720°C, 740°C, 760°C, 780°C or 800°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0049] As a preferred technical solution of the present invention, the coal gas is separated from the solid heat carrier by a separator after being heated.

[0050] Preferably, the separator is a gas-solid separator.

[0051] Preferably, the separated solid heat carrier is reheated.

[0052] As a preferred technical solution of the present invention, air is passed through the reheating process to burn the solid heat carrier gas to remove the coke formed on the surface of the solid heat carrier when the heat carrier gas is heated and to achieve reheating.

[0053] Preferably, the reheating is performed in a reheater.

[0054] Preferably, the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange.

[0055] As a preferred technical solution of the present invention, flue gas is generated during the reheating process.

[0056] Preferably, the flue gas is used as drying gas in the drying process after being processed by a waste heat recovery system.

[0057] Preferably, the temperature of the flue gas is 500-1000°C, for example, it may be 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C or 1000°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0058] As a preferred technical solution of the present invention, the process comprises: the solid heat carrier after fluidization heating heats the heat carrier gas, and the heated gas is used as a gas heat carrier to pyrolyze the raw material lump coal;

[0059] wherein the raw material lump coal is low-grade lump coal; the particle size of the raw material lump coal is 6-80mm; the raw material lump coal is dried before pyrolysis; the temperature of the drying gas in the drying process is 100-300°C; the wet flue gas formed in the drying process is dusted and condensed to recover condensed water; the temperature of the wet flue gas is 50-150°C; the heat source of the drying process is the waste heat recovered during the heating process of coal gas; the pyrolysis is countercurrent pyrolysis; the pyrolysis obtains semi-coke and oil gas; the temperature of the oil gas is 250-350°C; a heat recovery operation is also provided in the pyrolysis; the oil gas is introduced into a distillation tower for fractionation after dust removal; the dust removal equipment includes a gas-solid separator; the oil gas is introduced through the lower part of the distillation tower; after entering the distillation tower, the oil gas is cooled and heat-exchanged to 100-120°C by coal tar washing; the coal tar used for washing is extracted from the bottom of the distillation tower and after cooling and dust removal, its temperature is 50-80 % is returned to the bottom of the fractionation tower for cyclic washing, and the remaining part is heated and enters the flash tower. The coal tar at the top of the flash tower is returned to the dust removal operation, and the coal tar at the bottom of the flash tower is output as a product; the oil and gas after cooling are separated from the top of the tower in the fractionation; the oil and gas after cooling are separated to obtain light oil, water and coal gas; the light oil is returned to the fractionation tower; 80-95% of the coal gas is returned as heat carrier coal gas, and the remaining part is used as a product; the fractionation also includes extracting phenol-containing light oil from the 170-210℃ section of the fractionation tower; the phenol-containing light oil is subjected to phenol extraction to obtain dephenolized light oil and crude phenol; the dephenolized light oil is returned to the fractionation tower; the phenol content in the water is less than 1500ppm, and the oil content is less than 800ppm; the semi-coke obtained by pyrolysis is sent to the coke plant after three-stage cooling treatment; the three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling in sequence; the pressure of the steam in the heat exchange tube after heat exchange in the water-cooled wall tube cooling is 0.5-1MPa; the temperature of the semi-coke after cooling by the water-cooled wall tube is 350-450℃; a cold gas injection port is arranged at the cooling lower part of the water-cooled wall tube, and the cold gas enters the pyrolysis section and mixes with the heat carrier gas after heat exchange with the semi-coke and temperature rises; the cooling carrier in the circulating convection cooling is an inert gas; the temperature of the semi-coke after the circulating convection cooling is 100-180℃; the water spray cooling method is water mist cooling; the temperature of the semi-coke after the water spray cooling is less than 70℃; the heat carrier gas is pressurized before heating; the solid heat carrier heats the heat carrier gas in the mixing heating tube and / or the fluidized heater; the The temperature of the heated coal gas is 600-800℃; after the coal gas is heated, it is separated from the solid heat carrier by a separator; the separator is a gas-solid separator; the solid heat carrier obtained by separation is reheated; during the reheating process, air is passed through the combustion to remove the coke formed on the surface of the solid heat carrier when the heat carrier coal gas is heated and reheat is achieved; the reheating is carried out in the reheater; the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange; flue gas is formed during the reheating process; the flue gas is used as dry gas in the drying process after being treated by the waste heat recovery system; the temperature of the flue gas is 500-1000℃. .

[0060] In the present invention, the dust removal equipment includes a cyclone separator, a container of a sieve plate and / or a baffle, a high-temperature bag filter and an electric bag filter, but is not limited to the listed equipment, and other equipment that can achieve the same effect is also acceptable. Furthermore, in the present invention, the semi-coke will undergo a heat recovery operation before cooling to recover the high-energy heat carried by the semi-coke, and the recovered heat can be used for heating other places and power generation.

[0061] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0062] (1) In the present invention, since the energy of the high-temperature coal gas comes from the heat exchange of the solid heat carrier, the coal gas used as the carrier gas does not contain gases such as N2, CO and CO2 generated by the air-assisted combustion. That is, the process coal gas provided by the present invention has the advantages of high calorific value, small amount of sewage, and full energy utilization. The entire pyrolysis process is more efficient and more environmentally friendly.

[0063] (2) In the present invention, by online dephenolization of the reflux oil, the phenol content of the tower top wastewater is controlled to be less than 1500 ppm and the oil content is controlled to be less than 800 ppm, thereby greatly reducing the difficulty of wastewater treatment.

[0064] (3) In the present invention, by drying the raw material lump coal before pyrolysis, the amount of wastewater generated by pyrolysis can be reduced to 1 / 2-1 / 3 of that of the traditional blue charcoal technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a schematic diagram of a specific implementation in Example 1 of the present invention.

[0066] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0067] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0068] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0069] Example 1

[0070] This embodiment provides a lump coal pyrolysis process, such as Figure 1 As shown, the process includes: the solid heat carrier after fluidization heating heats the heat carrier gas, and the heated gas is used as a gas heat carrier to pyrolyze the raw material lump coal;

[0071] Among them, the raw material lump coal is low-grade lump coal; the particle size of the raw material lump coal is 6-80mm; the raw material lump coal is dried before pyrolysis; the temperature of the drying gas in the drying process is 200℃; the wet flue gas formed in the drying process is dusted and condensed to recover condensed water; the temperature of the wet flue gas is 120℃; the heat source of the drying process is the waste heat recovered from gas heating; the pyrolysis is countercurrent pyrolysis; the pyrolysis obtains semi-coke and oil gas; the temperature of the oil gas is 350℃; a heat recovery operation is also provided in the pyrolysis; the oil gas is passed into a distillation tower for fractionation after dust removal; the dust removal equipment includes a gas-solid separator; the oil gas is passed through the lower part of the distillation tower; the oil gas enters the fractionation tower After the tower, the coal tar is washed, cooled and heat-exchanged to 120°C; the coal tar used for washing is extracted from the bottom of the fractionation tower, and after cooling and dust removal, 50% of it is returned to the bottom of the fractionation tower for circulating washing, and the remaining part is heated and enters the flash tower, and the coal tar at the top of the flash tower is returned before the dust removal operation, and the coal tar at the bottom of the flash tower is output as a product; the cooled oil and gas are separated from the top of the tower in the fractionation; the cooled oil and gas are separated to obtain light oil, water and coal gas; the light oil is returned to the fractionation tower; 80% of the coal gas is returned as heat carrier coal gas, and the remaining part is used as a product; the fractionation also includes extracting phenol-containing light oil from the 170-210°C section of the fractionation tower; the phenol-containing light oil is subjected to a phenol extraction operation to obtain dephenolized light oil and crude phenol; the dephenolized light oil The semi-coke obtained by pyrolysis is sent to the coke plant after three-stage cooling treatment; the three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling in sequence; the pressure of the steam in the heat exchange tube after heat exchange in the water-cooled wall tube cooling is 1MPa; the temperature of the semi-coke after the water-cooled wall tube cooling is 430℃; a cold gas injection port is arranged at the lower part of the water-cooled wall tube cooling, and the cold gas enters the pyrolysis section and mixes with the heat carrier gas after heat exchange and temperature increase with the semi-coke; the cooling carrier in the circulating convection cooling is an inert gas; the temperature of the semi-coke after the circulating convection cooling is 180℃; the water spray cooling method is water mist cooling; the temperature of the semi-coke after the water spray cooling is less than 70℃; the heat carrier gas is heated before heating. pressure operation; the solid heat carrier heats the heat carrier gas in a mixing heating tube and / or a fluidized heater; the temperature of the heated gas is 800°C; after the gas is heated, it is separated from the solid heat carrier by a separator; the separator is a gas-solid separator; the solid heat carrier obtained by separation is reheated; during the reheating process, air is passed through for combustion to remove the coke formed on the surface of the solid heat carrier when the heat carrier gas is heated and to achieve reheating; the reheating is carried out in a reheater; the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange; flue gas is formed during the reheating process; the flue gas is used as dry gas in the drying process after being treated by the waste heat recovery system; the temperature of the flue gas is 800°C.

[0072] The calorific value of gas can reach 4000-4500kcal / Nm3 ; The coal tar yield is 1 percentage point higher than that of the traditional semi-coke furnace; the dust content of the coal tar product is less than 0.2%; the amount of wastewater generated is 45%-50% of that of the traditional semi-coke furnace, the phenol content in the wastewater is about 1500ppm, and the oil content is about 800ppm, which is easy to handle.

[0073] Example 2

[0074] This embodiment provides a lump coal pyrolysis process, the process comprising: a solid heat carrier after fluidization heating heats a heat carrier gas, and the heated gas is used as a gas heat carrier to pyrolyze the raw material lump coal;

[0075] Among them, the raw material lump coal is low-grade lump coal; the particle size of the raw material lump coal is 6-80mm; the raw material lump coal is dried before pyrolysis; the temperature of the drying gas in the drying process is 300°C; the wet flue gas formed in the drying process is dusted and condensed to recover condensed water; the temperature of the wet flue gas is 150°C; the heat source of the drying process is the waste heat recovered from gas heating; the pyrolysis is countercurrent pyrolysis; the pyrolysis obtains semi-coke and oil gas; the temperature of the oil gas is 350°C; a heat recovery operation is also provided in the pyrolysis; the oil gas is passed into a distillation tower for fractionation after dust removal; the dust removal equipment includes a gas-solid separator; the oil gas is passed through the lower part of the distillation tower; the oil gas enters the fractionation tower After the tower, the coal tar is washed, cooled and heat-exchanged to 120°C; the coal tar used for washing is extracted from the bottom of the fractionation tower, and after cooling and dust removal, 60% of it is returned to the bottom of the fractionation tower for circulating washing, and the remaining part is heated and enters the flash tower, and the coal tar at the top of the flash tower is returned before the dust removal operation, and the coal tar at the bottom of the flash tower is output as a product; the cooled oil and gas are separated from the top of the tower in the fractionation; the cooled oil and gas are separated to obtain light oil, water and coal gas; the light oil is returned to the fractionation tower; 80% of the coal gas is returned as heat carrier coal gas, and the remaining part is used as a product; the fractionation also includes extracting phenol-containing light oil from the 170-210°C section of the fractionation tower; the phenol-containing light oil is subjected to a phenol extraction operation to obtain dephenolized light oil and crude phenol; the dephenolized light oil The semi-coke obtained by pyrolysis is sent to the coke plant after three-stage cooling treatment; the three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling in sequence; the pressure of the steam in the heat exchange tube after heat exchange in the water-cooled wall tube cooling is 1MPa; the temperature of the semi-coke after the water-cooled wall tube cooling is 380℃; a cold gas injection port is arranged at the lower part of the water-cooled wall tube cooling, and the cold gas enters the pyrolysis section and mixes with the heat carrier gas after heat exchange and temperature increase with the semi-coke; the cooling carrier in the circulating convection cooling is an inert gas; the temperature of the semi-coke after the circulating convection cooling is 100℃; the water spray cooling method is water mist cooling; the temperature of the semi-coke after the water spray cooling is less than 70℃; the heat carrier gas is heated before heating. pressure operation; the solid heat carrier heats the heat carrier gas in a mixing heating tube and / or a fluidized heater; the temperature of the heated gas is 800°C; after the gas is heated, it is separated from the solid heat carrier by a separator; the separator is a gas-solid separator; the solid heat carrier obtained by separation is reheated; during the reheating process, air is passed through for combustion to remove the coke formed on the surface of the solid heat carrier when the heat carrier gas is heated and to achieve reheating; the reheating is carried out in a reheater; the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange; flue gas is formed during the reheating process; the flue gas is treated by a waste heat recovery system and used as dry gas in the drying process; the temperature of the flue gas is 850°C.

[0076] The calorific value of gas can reach 4000-4500kcal / Nm3 ; The coal tar yield is 1 percentage point higher than that of the traditional semi-coke furnace; the dust content of the coal tar product is less than 0.2%; the amount of wastewater generated is 35%-45% of that of the traditional semi-coke furnace, the phenol content in the wastewater is about 1500ppm, and the oil content is about 800ppm, which is easy to handle.

[0077] Example 3

[0078] This embodiment provides a lump coal pyrolysis process, the process comprising: a solid heat carrier after fluidization heating heats a heat carrier gas, and the heated gas is used as a gas heat carrier to pyrolyze the raw material lump coal;

[0079] Among them, the raw material lump coal is low-grade lump coal; the particle size of the raw material lump coal is 6-80mm; the raw material lump coal is dried before pyrolysis; the temperature of the drying gas in the drying process is 200°C; the wet flue gas formed in the drying process is dusted and condensed to recover condensed water; the temperature of the wet flue gas is 120°C; the heat source of the drying process is the waste heat recovered from gas heating; the pyrolysis is countercurrent pyrolysis; the pyrolysis obtains semi-coke and oil gas; the temperature of the oil gas is 300°C; a heat recovery operation is also provided in the pyrolysis; the oil gas is passed into a distillation tower for fractionation after dust removal; the dust removal equipment includes a gas-solid separator; the oil gas is passed through the lower part of the distillation tower; the oil gas enters the distillation tower After that, it is cooled by coal tar washing and heat exchanged to 100°C; the coal tar used for washing is extracted from the bottom of the fractionation tower, and after cooling and dust removal, 60% of it is returned to the bottom of the fractionation tower for circulating washing, and the remaining part is heated and enters the flash tower, and the coal tar at the top of the flash tower is returned before the dust removal operation, and the coal tar at the bottom of the flash tower is output as a product; in the fractionation, the cooled oil and gas are separated from the top of the tower; the cooled oil and gas are separated to obtain light oil, water and coal gas; the light oil is returned to the fractionation tower; 90% of the coal gas is returned as heat carrier coal gas, and the remaining part is used as a product; the fractionation also includes extracting phenol-containing light oil from the 170-210°C section of the fractionation tower; the phenol-containing light oil is subjected to phenol extraction to obtain dephenolized light oil and crude phenol; the dephenolized light oil is returned The semi-coke obtained by pyrolysis is sent to the coke plant after three-stage cooling treatment; the three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling in sequence; the pressure of the steam in the heat exchange tube after heat exchange in the water-cooled wall tube cooling is 0.7MPa; the temperature of the semi-coke after the water-cooled wall tube cooling is 350℃; a cold coal gas injection port is arranged at the lower part of the water-cooled wall tube cooling, and the cold coal gas enters the pyrolysis section and mixes with the heat carrier gas after heat exchange and temperature increase with the semi-coke; the cooling carrier in the circulating convection cooling is an inert gas; the temperature of the semi-coke after the circulating convection cooling is 150℃; the water spray cooling method is water mist cooling; the temperature of the semi-coke after the water spray cooling is less than 70℃; the heat carrier gas is heated before heating. Pressurized operation; the solid heat carrier heats the heat carrier gas in a mixing heating tube and / or a fluidized heater; the temperature of the heated gas is 700°C; after the gas is heated, it is separated from the solid heat carrier by a separator; the separator is a gas-solid separator; the solid heat carrier obtained by separation is reheated; during the reheating process, air is passed through for combustion to remove the coke formed on the surface of the solid heat carrier when the heat carrier gas is heated and to achieve reheating; the reheating is carried out in a reheater; the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange; flue gas is formed during the reheating process; the flue gas is treated by a waste heat recovery system and used as dry gas in the drying process; the temperature of the flue gas is 750°C.

[0080] The calorific value of gas can reach 4200-4700kcal / Nm3 ; The coal tar yield is 1 percentage point higher than that of the traditional semi-coke furnace; the dust content of the coal tar product is less than 0.2%; the amount of wastewater generated is 40%-50% of that of the traditional semi-coke furnace, the phenol content in the wastewater is about 1500ppm, and the oil content is about 800ppm, which is easy to handle.

[0081] Comparative Example 1

[0082] This comparative example provides a lump coal pyrolysis process, and this embodiment provides a lump coal pyrolysis process, the process comprising: a solid heat carrier after fluidization heating heats a heat carrier gas, and the heated gas is used as a gas heat carrier to pyrolyze the raw material lump coal;

[0083] The raw material lump coal is low-grade lump coal; the particle size of the raw material lump coal is 6-80 mm; the raw material lump coal is dried before pyrolysis; the temperature of the drying gas in the drying process is 200°C; the wet flue gas formed in the drying process is dusted and condensed to recover condensed water; the temperature of the wet flue gas is 120°C; the heat source of the drying process is the waste heat recovered from gas heating; the pyrolysis is countercurrent pyrolysis; the pyrolysis obtains semi-coke and oil gas; the temperature of the oil gas is 350°C; the pyrolysis is also provided with The heat recovery operation is arranged; the oil and gas are introduced into the distillation tower for fractionation after dust removal; the dust removal equipment includes a gas-solid separator; the oil and gas are washed and cooled by traditional ammonia water to obtain coal tar, sewage and coal gas; 80% of the coal gas is returned as heat carrier coal gas, and the remaining part is used as product; the semi-coke obtained by pyrolysis is sent to the coke plant after three-stage cooling treatment; the three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling in sequence; the pressure of the steam in the wall tube after heat exchange in the water-cooled wall tube cooling is 1M Pa; the temperature of the semi-coke after cooling by the water-cooled wall tube is 390°C; the cooling carrier in the circulating convection cooling is an inert gas; the temperature of the semi-coke after the circulating convection cooling is 180°C; the water spray cooling method is water mist cooling; the temperature of the semi-coke after the water spray cooling is less than 70°C; the heat carrier gas is pressurized before heating; the solid heat carrier heats the heat carrier gas in a mixed heating tube and / or a fluidized heater; the temperature of the heated gas is 800°C; after the gas is heated, it is separated from the solid heat carrier by a separator; the separator is a gas-solid separator; the solid heat carrier obtained by the separation is reheated; during the reheating process, air is passed through for combustion to remove the coke formed on the surface of the solid heat carrier when the heat carrier gas is heated and reheating is achieved; the reheating is performed in a reheater; the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange; flue gas is formed during the reheating process; the flue gas is used as dry gas in the drying process after being treated by the waste heat recovery system; the temperature of the flue gas is 800°C.

[0084] The calorific value of gas can reach 4000-5000kcal / Nm 3 The coal tar yield is 1 percentage point higher than that of the traditional semi-coke furnace; the dust content of the coal tar product is less than 0.2%; the amount of wastewater generated is 2 / 3-1 / 2 of that of the traditional semi-coke furnace, the phenol content in the wastewater is 12000-15000ppm, and the oil content is 5000-8000ppm, which is similar to the traditional process and is difficult to handle.

[0085] Comparative Example 2

[0086] This comparative example provides a lump coal pyrolysis process, the process comprising: a solid heat carrier after fluidization heating heats a heat carrier coal gas, and the heated coal gas is used as a gas heat carrier to pyrolyze the raw material lump coal;

[0087] The raw material lump coal is low-grade lump coal; the particle size of the raw material lump coal is 6-80mm; the raw material lump coal is dried before pyrolysis; the temperature of the drying gas in the drying process is 200°C; the wet flue gas formed in the drying process is dusted and condensed to recover condensed water; the temperature of the wet flue gas is 120°C; the heat source of the drying process is the waste heat recovered from gas heating; the pyrolysis is countercurrent pyrolysis; the pyrolysis obtains semi-coke and oil gas; the temperature of the oil gas is 350°C; a heat recovery operation is also provided in the pyrolysis; the oil gas is passed into a distillation tower for fractionation after dust removal; The dust removal equipment includes a gas-solid separator; the oil and gas are introduced through the lower part of the fractionation tower; after entering the fractionation tower, the oil and gas are washed with coal tar to cool down and heat exchanged to 120°C; the coal tar used for washing is extracted from the bottom of the fractionation tower, and after the dust removal operation, 50% of it is returned to the bottom of the tower for cyclic washing, and the remaining part is used as the product; the cooled oil and gas are separated from the top of the tower during the fractionation; the cooled oil and gas are separated to obtain light oil, water and coal gas; the light oil is produced as the product; 80% of the coal gas is returned as heat carrier coal gas, and the remaining part is used as the product; the semi-coke obtained by pyrolysis is sent to the coke plant after three-stage cooling treatment; The three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling in sequence; the pressure of the steam in the wall tube after heat exchange in the water-cooled wall tube cooling is 1MPa; the temperature of the semi-coke after the water-cooled wall tube cooling is 390℃; the cooling carrier in the circulating convection cooling is an inert gas; the temperature of the semi-coke after the circulating convection cooling is 180℃; the water spray cooling method is water mist cooling; the temperature of the semi-coke after the water spray cooling is less than 70℃; the heat carrier gas is pressurized before heating; the solid heat carrier heats the heat carrier gas in the mixed heating tube and / or fluidized heater; The temperature of the heated coal gas is 800°C; after the heating, the coal gas is separated from the solid heat carrier by a separator; the separator is a gas-solid separator; the solid heat carrier obtained by the separation is reheated; during the reheating process, air is passed through for combustion to remove the coke formed on the surface of the solid heat carrier when the heat carrier coal gas is heated and to achieve reheating; the reheating is carried out in a reheater; the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange; flue gas is formed during the reheating process; the flue gas is treated by a waste heat recovery system and used as dry gas in the drying process; the temperature of the flue gas is 800°C.

[0088] The calorific value of gas can reach 4000-5000kcal / Nm 3 The coal tar yield is 1 percentage point higher than that of the traditional semi-coke furnace; the dust content of the coal tar product is less than 0.2%; the amount of wastewater generated is 1 / 2-1 / 3 of that of the traditional semi-coke furnace, the phenol content in the wastewater is 12000-15000ppm, and the oil content is 5000-8000ppm, which is similar to the traditional process and is difficult to handle.

[0089] Comparative Example 3

[0090] The difference between this comparative example and Example 1 is that the reheating, drying and condensation water recovery processes are removed. The calorific value of coal gas is about 1500-2000 kcal / Nm 3 , difficult to utilize; coal tar yield is 6%; the amount of wastewater generated is similar to that of traditional blue charcoal furnace wastewater, the phenol content in the wastewater is about 1500ppm, and the oil content is about 800ppm, which is easy to handle.

[0091] Based on the results of the above embodiments and comparative examples, the present invention provides a new lump coal pyrolysis process coupled with fluidized heating, in which the pyrolysis coal gas is heated by a solid heat carrier coupled with circulating fluidization, and the heated high-temperature coal gas is used as a gas heat carrier to pyrolyze the raw coal. Since the energy of the high-temperature coal gas comes from the heat exchange of the solid heat carrier, the coal gas used as the carrier gas does not contain gases such as N2, CO and CO2 produced by air combustion, so the calorific value of the coal gas produced during the pyrolysis process is increased and the quality is greatly improved, which will promote the entire pyrolysis process to be more efficient and more environmentally friendly. At the same time, by online dephenolization of the reflux oil, the phenol content of the top wastewater is controlled to be less than 1500ppm and the oil content is controlled to be less than 800ppm, which greatly reduces the difficulty of wastewater treatment.

[0092] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0093] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0094] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A lump coal pyrolysis process, characterized in that: The process comprises: the solid heat carrier after fluidization heating heats the heat carrier coal gas, after the coal gas is heated, it is separated from the solid heat carrier through a separator, the separated solid heat carrier is reheated, flue gas is formed during the reheating process, the flue gas is treated by a waste heat recovery system and used as dry gas in the drying process, the heated coal gas is used as a gas heat carrier to pyrolyze the raw material lump coal, the pyrolysis obtains semi-coke and oil gas, the semi-coke is sent to the coke plant after three-stage cooling treatment, the oil gas is passed into the fractionation tower after dust removal for separation After distillation, the oil and gas enter the distillation tower and are cooled and heat-exchanged to 100-120°C by coal tar washing. The coal tar used for washing is extracted from the bottom of the distillation tower, and after cooling and dust removal, 50-80% of it is returned to the bottom of the distillation tower for circulating washing, and the remaining part enters the flash tower after heating. The coal tar at the top of the flash tower is returned before the dust removal operation, and the coal tar at the bottom of the flash tower is output as a product. The cooled oil and gas are separated from the top of the tower during the distillation. The cooled oil and gas are separated to obtain light oil, water and coal gas, and the light oil returns to the distillation tower.

2. The process according to claim 1, characterized in that The raw material lump coal is low-grade lump coal.

3. The process according to claim 1, characterized in that The particle size of the raw material lump coal is 6-80 mm.

4. The process according to claim 1, characterized in that The raw material lump coal is dried before pyrolysis.

5. The process according to claim 4, characterized in that The temperature of the drying gas in the drying process is 100-300°C.

6. The process according to claim 4, characterized in that The wet flue gas formed in the drying process is subjected to dust removal and condensation to recover condensed water.

7. The process according to claim 6, characterized in that The temperature of the wet flue gas is 50-150°C.

8. The process according to claim 4, characterized in that The heat source for the drying process is the waste heat recovered during the gas heating process.

9. The process according to claim 1, characterized in that The pyrolysis is countercurrent pyrolysis.

10. The process according to claim 1, characterized in that The temperature of the oil gas is 250-350°C.

11. The process according to claim 1, characterized in that The pyrolysis process is also provided with a heat recovery operation.

12. The process of claim 1, wherein: The dust removal equipment includes a gas-solid separator.

13. The process of claim 1, wherein: The oil and gas are introduced into the lower part of the distillation tower.

14. The process of claim 1, wherein: 80-95% of the coal gas is returned as heat carrier gas, and the rest is used as product.

15. The process of claim 1, wherein: The fractionation also includes extracting phenol-containing light oil from the 170-210° C. section of the fractionation tower.

16. The process of claim 15, wherein: The phenol-containing light oil is subjected to a phenol extraction operation to obtain dephenolized light oil and crude phenol.

17. The process of claim 16, wherein: The dephenolized light oil is returned to the fractionation tower.

18. The process of claim 1, wherein: The phenol content in the water is less than 1500 ppm, and the oil content in the water is less than 800 ppm.

19. The process of claim 1, wherein: The three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling performed in sequence.

20. The process of claim 19, wherein: The pressure of the steam in the heat exchange tube after heat exchange during cooling of the water-cooled wall tube is 0.5-1Mpa.

21. The process of claim 19, wherein: The temperature of the semi-coke after cooling of the water-cooled wall tube is 350-450°C.

22. The process of claim 19, wherein: A cold gas injection port is arranged at the cooling lower part of the water-cooled wall tube, and the cold gas is heated by heat exchange with the semi-coke and then enters the pyrolysis section to mix with the heat carrier gas.

23. The process of claim 19, wherein: The cooling carrier in the circulating convection cooling is an inert gas.

24. The process of claim 19, wherein: The temperature of the semi-coke after the circulating convection cooling is 100-180°C.

25. The process of claim 19, wherein: The water spray cooling method is water mist cooling.

26. The process of claim 19, wherein: The temperature of the semi-coke after the water spray cooling is less than 70°C.

27. The process of claim 1, wherein: The heat carrier gas is pressurized before being heated.

28. The process of claim 1, wherein: The solid heat carrier heats the heat carrier gas in a mixing heating tube and / or a fluidized heater.

29. The process of claim 1, wherein: The temperature of the heated coal gas is 600-800°C.

30. The process of claim 1, wherein: The separator is a gas-solid separator.

31. The process of claim 1, wherein: In the reheating process, air is passed through for combustion to remove coke formed on the surface of the solid heat carrier when the heat carrier gas is heated and to achieve reheating.

32. The process of claim 1, wherein: The reheating is performed in a reheater.

33. The process of claim 1, wherein: The reheating may also be achieved by adding heavy fuel or heat medium for heat exchange.

34. The process of claim 1, wherein: The temperature of the flue gas is 500-1000°C.

35. The process according to any one of claims 1 to 34, characterized in that The process comprises: the solid heat carrier after fluidization heating heats the heat carrier coal gas, and the heated coal gas is used as a gas heat carrier to pyrolyze the raw material lump coal; The raw material lump coal is low-grade lump coal; the particle size of the raw material lump coal is 6-80mm; the raw material lump coal is dried before pyrolysis; the temperature of the drying gas in the drying process is 100-300°C; the wet flue gas formed in the drying process is dusted and condensed to recover condensed water; the temperature of the wet flue gas is 50-150°C; the heat source of the drying process is the waste heat recovered during the gas heating process; the pyrolysis is countercurrent pyrolysis; the pyrolysis obtains semi-coke and oil gas; the temperature of the oil gas is 250-350°C; a heat recovery operation is also provided in the pyrolysis; the oil gas is introduced into the fractionation tower for fractionation after dust removal; the dust removal equipment includes a gas-solid separator; the oil gas is introduced through the lower part of the fractionation tower; after entering the fractionation tower, the oil gas is washed with coal tar and cooled and heat-exchanged to 100-120°C; the coal tar used for washing is extracted from the bottom of the fractionation tower, and 50-80% of it is cooled and dust-removed after cooling. The tar is returned to the bottom of the fractionation tower for cyclic washing, and the remaining part is heated and enters the flash tower. The coal tar at the top of the flash tower is returned to the dust removal operation, and the coal tar at the bottom of the flash tower is output as a product; the oil and gas after cooling are separated from the top of the tower in the fractionation; the oil and gas after cooling are separated to obtain light oil, water and coal gas; the light oil returns to the fractionation tower; 80-95% of the coal gas is returned as heat carrier coal gas, and the remaining part is used as a product; the fractionation also includes extracting phenol-containing light oil from the 170-210℃ section of the fractionation tower; the phenol-containing light oil is subjected to phenol extraction to obtain dephenolized light oil and crude phenol; the dephenolized light oil returns to the fractionation tower; the phenol content in the water is less than 1500ppm, and the oil content is less than 800ppm; the semi-coke obtained by pyrolysis is sent to the coke plant after three-stage cooling treatment; the three-stage cooling includes water-cooled wall tube cooling, circulating convection cooling and water spray cooling in sequence; the pressure of the steam in the heat exchange tube after heat exchange in the water-cooled wall tube cooling is 0.5-1MPa; the temperature of the semi-coke after cooling by the water-cooled wall tube is 350-450℃; a cold gas injection port is arranged at the cooling lower part of the water-cooled wall tube, and the cold gas enters the pyrolysis section and mixes with the heat carrier gas after heat exchange with the semi-coke and temperature rises; the cooling carrier in the circulating convection cooling is an inert gas; the temperature of the semi-coke after the circulating convection cooling is 100-180℃; the water spray cooling method is water mist cooling; the temperature of the semi-coke after the water spray cooling is less than 70℃; the heat carrier gas is pressurized before heating; the solid heat carrier heats the heat carrier gas in the mixing heating tube and / or the fluidized heater; the The temperature of the heated coal gas is 600-800℃; after the coal gas is heated, it is separated from the solid heat carrier by a separator; the separator is a gas-solid separator; the solid heat carrier obtained by separation is reheated; during the reheating process, air is passed through the combustion to remove the coke formed on the surface of the solid heat carrier when the heat carrier coal gas is heated and reheating is achieved; the reheating is carried out in the reheater; the reheating also includes heat exchange by adding heavy fuel or heat medium; flue gas is formed during the reheating process; the flue gas is used as dry gas in the drying process after being treated by the waste heat recovery system; the temperature of the flue gas is 500-1000℃. .

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