A shale distillation process

Abstract

The present invention relates to a shale dry distillation process, which comprises: heating the heat carrier dry distillation gas by a fluidized heated solid heat carrier, and using the heated dry distillation gas as a gas heat carrier to dry distill shale. The present invention increases the calorific value of the dry distillation gas, improves its quality, fully utilizes the energy of the drying section, and reduces the amount of sewage; the shale ash has a low carbon content, and the secondary cooling energy is fully recovered, thereby promoting the entire shale dry distillation process to be more efficient and more environmentally friendly.

Description

Technical Field

[0001] The invention relates to the field of shale distillation, and in particular to a shale distillation process. Background Art

[0002] At present, my country's oil shale reserves are very rich, with national oil shale reserves of about 719.9 billion tons, equivalent to about 47.6 billion tons of shale oil, ranking fourth in the world after the United States, Brazil and Estonia. my country is a country "rich in coal, poor in oil, and little gas". How to use the rich reserves of oil shale and coal to convert them into oil and gas is the only way to alleviate the energy shortage, which is also the direction that the country has strongly supported in recent years.

[0003] Although the block shale retorting technology is widely used, the Fushun furnace has been developed for more than 80 years, with continuous technical improvements and continuous improvement in production efficiency. It is the main production process of shale retorting in China and the most representative retorting technology for shale retorting. Although CN101993703A discloses an oil shale retorting furnace and retorting process, which passes through two retorting stages and uses full-cycle retorting dry gas for heating, the process has the following shortcomings: ① There is no drying section before the retorting section, and the moisture carried by the oil shale enters the fractionation system, resulting in a large amount of sewage; ② The gas after combustion in the generation section is used as the gas heat carrier for retorting, so that the retorting dry gas is mixed with N2 carried by the air and CO, CO2 and a large amount of water vapor produced by combustion, and the retorting dry gas has poor quality and low calorific value. CN101818072A discloses an oil shale distillation system, wherein a material distribution system is connected to a reaction furnace through relevant conveying and output pipelines, the reaction furnace is connected to a distillation gas circulation system through a control system and relevant conveying and output pipelines, and the distillation gas circulation system is connected to a cooling system through relevant conveying and output pipelines; the system can complete the crushing, screening, furnace loading, heating, collection of shale distillation gas, cooling and collection of shale semi-coke, etc. of oil shale; the material distribution system places large-size oil shale at the lower part of the material layer and small-size oil shale at the upper part of the material layer, thereby avoiding the problem that small-size particles are easily leaked from the grate and semi-coke particles are easily stuck in the gaps of the grate and do not fall off, thereby improving the utilization rate of oil shale, reducing the resistance of the material layer, avoiding the powder in the material layer from being entrained and carried out, and effectively reducing the dust content; reducing the temperature of semi-coke out of the furnace, improving the utilization efficiency of heat energy, and making the semi-coke treatment convenient; the invention has reasonable design, compact layout, reliable performance, low carbon and environmental protection, low operating cost, and is easy to industrially extract shale oil. This process also has the following shortcomings: ① There is no drying section before the distillation section, and the moisture carried by the oil shale enters the distillation system, resulting in a large amount of wastewater; ② The gas after combustion in the generation section is used as the gas heat carrier for distillation, so that the distillation dry gas is mixed with N2 carried by the air and CO, CO2 and a large amount of water vapor produced by combustion, and the distillation dry gas is of poor quality and low calorific value; ③ The shale oil yield is low; ④ The carbon utilization is insufficient, the shale ash has a high carbon content and low thermal efficiency, etc. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a shale distillation process. Since the distillation dry gas used as a carrier gas does not contain gases such as N2, CO and CO2 produced by air combustion, the calorific value of the distillation dry gas produced during the distillation process is increased and the quality is greatly improved, which will promote the entire shale distillation process to be more efficient and more environmentally friendly.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention provides a shale dry distillation process, which comprises: heating a heat carrier dry distillation gas by a fluidized heated solid heat carrier, and using the heated dry distillation gas as a gas heat carrier to dry distill shale.

[0007] In the present invention, the dry distillation gas is heated by coupling the circulating fluidized solid heat carrier, and the heated high-temperature dry distillation gas is used as a gas heat carrier to dry distill the oil shale. Since the energy of the high-temperature dry distillation gas comes from the heat exchange of the solid heat carrier, the dry distillation 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 dry distillation gas produced in the dry distillation process is increased, and the quality is greatly improved. That is, the present invention increases the calorific value of the dry distillation gas, improves the quality, sets the drying section to fully utilize the energy, and reduces the amount of sewage; the shale ash has a low carbon content, and the secondary cooling energy is fully recovered, etc., thereby promoting the entire shale dry distillation process to be more efficient and more environmentally friendly.

[0008] As a preferred technical solution of the present invention, the heat carrier dry distillation gas is pressurized before heating.

[0009] Preferably, the solid heat carrier heats the heat carrier retorting gas in a mixing heating tube and / or a fluidized heater.

[0010] Preferably, the temperature of the heated dry distillation gas is 500-550°C, for example, 500°C, 510°C, 520°C, 530°C, 540°C or 550°C, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0011] As a preferred technical solution of the present invention, the dry distillation gas is separated from the solid heat carrier through a separator after being heated.

[0012] Preferably, the separator is a gas-solid separator.

[0013] Preferably, the separated solid heat carrier is reheated.

[0014] As a preferred technical solution of the present invention, the reheating is carried out in a reheater.

[0015] Preferably, the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange.

[0016] As a preferred technical solution of the present invention, flue gas is generated during the reheating process.

[0017] Preferably, the flue gas is used as drying gas in the drying process after being processed by a waste heat recovery system.

[0018] Preferably, the temperature of the flue gas is 500-800°C, for example, it may be 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0019] As a preferred technical solution of the present invention, the particle size of the shale is 3-80 mm, for example, it can be 3 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.

[0020] Preferably, the shale is dried before retorting.

[0021] 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.

[0022] Preferably, the wet flue gas formed in the drying process is subjected to dust removal and condensation to recover condensed water.

[0023] 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.

[0024] Preferably, the heat source for the drying process is waste heat recovered from heating the dry distillation gas.

[0025] As a preferred technical solution of the present invention, the dry distillation is countercurrent dry distillation.

[0026] Preferably, the dry distillation obtains shale ash and dry distillation oil gas.

[0027] Preferably, the temperature of the distillation oil gas is 200-350°C, for example, it can be 200°C, 210°C, 220°C, 230°C, 230°C, 240°C, 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.

[0028] Preferably, a heat recovery operation is also provided in the dry distillation.

[0029] Preferably, the pressure difference between the dry distillation oil gas and the wet flue gas discharged from the drying section is 0.2-10 kPa, and the pressure of the wet flue gas is greater than the pressure of the dry distillation oil gas.

[0030] As a preferred technical solution of the present invention, the dry distillation oil gas is introduced into a distillation tower for washing and heat exchange after dust removal.

[0031] Preferably, the dust removal equipment includes a gas-solid separator.

[0032] Preferably, the dry distillation oil gas is introduced through the lower part of the distillation tower.

[0033] Preferably, the distillation oil gas is cooled and heat-exchanged to 100-120°C after shale oil washing, 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 unlisted values ​​within this range are also applicable.

[0034] Preferably, 50-80% of the shale oil used for washing is extracted from the bottom of the distillation tower and returned to the bottom of the distillation tower for circulation washing after cooling and dust removal, and the remaining shale oil enters the flash tower. The shale oil at the top of the flash tower is mixed and diluted with the bottom oil before returning to the centrifuge. The shale oil at the bottom of the flash tower as a product can be, for example, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0035] Preferably, the dry distillation oil gas after cooling is separated at the top of the fractionation tower.

[0036] Preferably, the cooled dry distillation oil gas is separated to obtain light oil, water and dry distillation gas.

[0037] Preferably, 80-95% of the dry distillation gas is returned as the heat carrier dry distillation gas, and the rest is used as the 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.

[0038] As a preferred technical solution of the present invention, the shale ash obtained by dry distillation is reused after secondary cooling.

[0039] Preferably, the secondary cooling includes water-cooled wall tube cooling and circulating convection cooling performed sequentially.

[0040] 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.

[0041] Preferably, the temperature of the shale ash after cooling of the water-cooled wall tubes is 400-500°C, for example, it can be 400°C, 420°C, 440°C, 460°C, 480°C or 500°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0042] Preferably, in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the hot gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier, and then air is continued to be introduced to cool the shale ash.

[0043] Preferably, in the circulating convection cooling operation, at least two circulating convection coolers are set for switchable use, for example, there can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 units, but are not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0044] Preferably, the temperature of the hot gas is 700-1000°C, for example, it can be 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.

[0045] Preferably, the temperature of the shale ash after the circulating convection cooling is less than 100°C, for example, it can be 100°C, 90°C, 80°C, 70°C, 60°C, 50°C, 40°C, 30°C or 20°C, etc., 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 process comprises: heating the heat carrier dry distillation gas by coupling the circulating fluidized solid heat carrier, and using the heated dry distillation gas as a gas heat carrier to dry distill the shale;

[0047] Wherein, the heat carrier retort gas is pressurized before heating; the solid heat carrier heats the heat carrier retort gas in a mixed heating tube and / or a fluidized heater; the temperature of the heated retort gas is 500-550°C; after the heating of the retort gas, 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; 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 generated 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 500-800°C; the particle size of the shale is 3-80mm; the shale is dried before dry distillation; the temperature of the dry gas in the drying process is 100-300℃; 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℃; the heat source of the drying process is the waste heat recovered from the heating of the dry distillation gas; the dry distillation is countercurrent dry distillation; the dry distillation obtains shale ash and dry distillation oil gas; the temperature of the dry distillation oil gas is 200-350℃; the dry distillation is also provided with a heat recovery operation; the pressure difference between the dry distillation oil gas and the wet flue gas discharged from the drying section is 0.2-10kPa, and the pressure of the wet flue gas is greater than the pressure of the dry distillation oil gas; the dry distillation oil gas is passed into the fractionation tower for washing after dust removal Heat exchange; the dust removal equipment includes a gas-solid separator; the dry distillation oil gas is introduced through the lower part of the fractionation tower; the dry distillation oil gas is cooled and heat-exchanged to 100-120°C after shale oil washing; the shale oil used for washing is extracted from the bottom of the fractionation tower, and after cooling and dust removal, 50-80% of it is returned to the bottom of the fractionation tower for cyclic washing, and the remaining shale oil enters the flash tower, and the shale oil at the top of the flash tower is mixed and diluted with the bottom oil before returning to the centrifuge, and the shale oil at the bottom of the flash tower is used as the product; the dry distillation oil gas after cooling is separated from the top of the fractionation tower; the dry distillation oil gas after cooling is separated to obtain light oil, water and dry distillation gas; 80-95% of the dry distillation gas is returned as the heat carrier dry distillation gas, and the remaining part is used as the product; the shale oil obtained by dry distillation The shale ash is reused after secondary cooling; the secondary cooling includes water-cooled wall tube cooling and circulating convection 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 shale ash after the water-cooled wall tube cooling is 400-500℃; in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the hot gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier, and then air is continued to be introduced to cool the shale ash; in the circulating convection cooling operation, at least two circulating convection coolers are set for switch use; the temperature of the hot gas is 700-1000℃; the temperature of the shale ash after the circulating convection cooling is less than 100℃.

[0048] In the present invention, the gas-solid separator in the dust removal operation can be a gas-solid separation device such as a cyclone separator, a bag dust collector, and an electric bag dust collector.

[0049] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0050] In the process provided by the present invention, since the energy of the high-temperature pyrolysis dry gas comes from the heat exchange of a solid heat carrier, the pyrolysis dry 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 pyrolysis dry gas produced in the pyrolysis process is increased and the quality is greatly improved. That is, the present invention increases the calorific value of the pyrolysis dry gas, improves its quality, fully utilizes the energy of the drying section, and reduces the amount of sewage; the shale ash has a low carbon content, and the secondary cooling energy is fully recovered, thereby promoting the entire shale pyrolysis process to be more efficient and more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of a specific implementation in Example 1 of the present invention.

[0052] 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

[0053] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0054] 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:

[0055] Example 1

[0056] This embodiment provides a shale distillation process, such as Figure 1 As shown, the process includes: heating the heat carrier dry distillation gas by fluidized heated solid heat carrier, and the heated dry distillation gas is used as a gas heat carrier to dry distill the shale;

[0057] Wherein, the heat carrier retort gas is pressurized before heating; the solid heat carrier heats the heat carrier retort gas in a mixing heating tube and / or a fluidized heater; the temperature of the heated retort gas is 550°C; after heating, the retort gas 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; 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 a waste heat recovery system; the temperature of the flue gas is 700℃; the particle size of the shale is 3-80mm; the shale is dried before distillation; the temperature of the drying gas in the drying process is 250℃; 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 the heating of the distillation dry gas; the distillation is countercurrent distillation; the distillation obtains shale ash and distillation oil gas; the temperature of the distillation oil gas is 350℃; the distillation is also provided with a heat recovery operation; the pressure difference between the distillation oil gas and the wet flue gas discharged from the drying section is 0.2-10kPa, and the pressure of the wet flue gas is greater than that of the distillation The pressure of oil and gas; the dry distillation oil and gas are introduced into the fractionation tower for washing and heat exchange after dust removal; the dust removal equipment includes a gas-solid separator; the dry distillation oil and gas are introduced into the lower part of the fractionation tower; the dry distillation oil and gas are cooled and heat-exchanged to 120°C after shale oil washing; the shale oil 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 cyclic washing, and the remaining shale oil enters the flash tower, and the shale oil at the top of the flash tower is mixed and diluted with the bottom oil before returning to the centrifuge, and the shale oil at the bottom of the flash tower is used as the product; the dry distillation oil and gas after cooling is separated from the top of the fractionation tower; the dry distillation oil and gas after cooling are separated to obtain light oil, water and dry distillation gas; 80% of the dry distillation gas is returned as the heat carrier dry distillation gas, and the rest is used as the product; the shale ash obtained by the dry distillation is reused after secondary cooling; the secondary cooling includes water-cooled wall tube cooling and circulating convection 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 shale ash after the water-cooled wall tube cooling is 450℃; in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the hot gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier; the temperature of the hot gas is 900℃; the temperature of the shale ash after the circulating convection cooling is 70℃.

[0058] The calorific value of dry distillation gas can reach 5000-5500kcal / Nm 3 ; The shale oil yield is 1 percentage point higher than that of the traditional Fushun furnace; the amount of wastewater generated is 35%-40% of that of the traditional Fushun furnace.

[0059] Example 2

[0060] This embodiment provides a shale dry distillation process, the process comprising: heating the heat carrier dry distillation gas by fluidized heating of the solid heat carrier, and using the heated dry distillation gas as the gas heat carrier to dry distill the shale;

[0061] Wherein, the heat carrier retort gas is pressurized before heating; the solid heat carrier heats the heat carrier retort gas in a mixing heating tube and / or a fluidized heater; the temperature of the heated retort gas is 550°C; after heating, the retort gas 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; 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 a waste heat recovery system; the temperature of the flue gas is 700℃; the particle size of the shale is 3-80mm; the shale is dried before distillation; 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 110℃; the heat source of the drying process is the waste heat recovered from the heating of the distillation dry gas; the distillation is countercurrent distillation; the distillation obtains shale ash and distillation oil gas; the temperature of the distillation oil gas is 350; the distillation is also provided with a heat recovery operation; the pressure difference between the distillation oil gas and the wet flue gas discharged from the drying section is 0.2-10kPa, and the pressure of the wet flue gas is greater than that of the distillation oil The pressure of the gas; the dry distillation oil gas is introduced into the fractionation tower for washing and heat exchange after dust removal; the dust removal equipment includes a gas-solid separator; the dry distillation oil gas is introduced through the lower part of the fractionation tower; the dry distillation oil gas is cooled and heat-exchanged to 110°C after shale oil washing; the shale oil used for washing is extracted from the bottom of the fractionation tower, and after cooling and dust removal, 55% of it is returned to the bottom of the fractionation tower for cyclic washing, and the remaining shale oil enters the flash tower, and the shale oil at the top of the flash tower is mixed and diluted with the bottom oil before returning to the centrifuge, and the shale oil at the bottom of the flash tower is used as the product; the dry distillation oil gas after cooling is separated from the top of the fractionation tower; the dry distillation oil gas after cooling is separated to obtain light oil, water and dry distillation gas; the dry 80% of the distillation gas is returned as the heat carrier dry distillation gas, and the rest is used as the product; the shale ash obtained by the dry distillation is reused after secondary cooling; the secondary cooling includes water-cooled wall tube cooling and circulating convection 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 shale ash after the water-cooled wall tube cooling is 400℃; in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the hot gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier; the temperature of the hot gas is 900℃; the temperature of the shale ash after the circulating convection cooling is 60℃.

[0062] The calorific value of dry distillation gas can reach 5000-5500kcal / Nm 3 ; The shale oil yield is 1 percentage point higher than that of the traditional Fushun furnace; the amount of wastewater generated is 40%-45% of that of the traditional Fushun furnace.

[0063] Example 3

[0064] This embodiment provides a shale dry distillation process, the process comprising: heating the heat carrier dry distillation gas by fluidized heating of the solid heat carrier, and using the heated dry distillation gas as the gas heat carrier to dry distill the shale;

[0065] Wherein, the heat carrier retort gas is pressurized before heating; the solid heat carrier heats the heat carrier retort gas in a mixing heating tube and / or a fluidized heater; the temperature of the heated retort gas is 500°C; after the retort 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; 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 in the reheating process; the flue gas is used as dry gas in the drying process after being treated by a waste heat recovery system; the temperature of the flue gas is 650℃; the particle size of the shale is 3-80mm; the shale is dried before distillation; 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 110℃; the heat source of the drying process is the waste heat recovered from the heating of the distillation dry gas; the distillation is countercurrent distillation; the distillation obtains shale ash and distillation oil gas; the temperature of the distillation oil gas is 250℃; the distillation is also provided with a heat recovery operation; the pressure difference between the distillation oil gas and the wet flue gas discharged from the drying section is 0.2-10kPa, and the pressure of the wet flue gas is greater than that of the distillation oil The pressure of the gas; the dry distillation oil gas is introduced into the fractionation tower for washing and heat exchange after dust removal; the dust removal equipment includes a gas-solid separator; the dry distillation oil gas is introduced through the lower part of the fractionation tower; the dry distillation oil gas is cooled and heat-exchanged to 100°C after shale oil washing; the shale oil 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 cyclic washing, and the remaining shale oil enters the flash tower, and the shale oil at the top of the flash tower is mixed and diluted with the bottom oil before returning to the centrifuge, and the shale oil at the bottom of the flash tower is used as the product; the dry distillation oil gas after cooling is separated from the top of the fractionation tower; the dry distillation oil gas after cooling is separated to obtain light oil, water and dry distillation gas; the dry 90% of the distillation gas is returned as the heat carrier dry distillation gas, and the rest is used as the product; the shale ash obtained by the dry distillation is reused after secondary cooling; the secondary cooling includes water-cooled wall tube cooling and circulating convection cooling in sequence; the pressure of the steam in the heat exchange tube after heat exchange in the water-cooled wall tube cooling is 0.5MPa; the temperature of the shale ash after the water-cooled wall tube cooling is 400℃; in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the hot gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier; the temperature of the hot gas is 800℃; the temperature of the shale ash after the circulating convection cooling is 80℃.

[0066] The calorific value of dry distillation gas can reach 5300-6000kcal / Nm 3 ; The shale oil yield is 1 percentage point higher than that of the traditional Fushun furnace; the amount of wastewater generated is 40%-45% of that of the traditional Fushun furnace.

[0067] Comparative Example 1

[0068] This comparative example provides a shale dry distillation process, which comprises: heating the heat carrier dry distillation gas by fluidized heating of the solid heat carrier, and using the heated dry distillation gas as the gas heat carrier to dry distill the shale;

[0069] The heat carrier retort gas is pressurized before heating; the solid heat carrier heats the heat carrier retort gas in a mixing heating tube and / or a fluidized heater; the temperature of the heated retort gas is 550°C; after heating, the retort gas 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; the reheating is carried out in a reheater; the reheating can also be achieved by adding heavy fuel or heat medium for heat exchange. The present invention relates to the following embodiments: flue gas is formed in the reheating process; the flue gas is discharged after recovering energy through waste heat recovery; the temperature of the flue gas is 700°C; the particle size of the shale is 3-80mm; the dry distillation is countercurrent dry distillation; the dry distillation obtains shale ash and dry distillation oil gas; the temperature of the dry distillation oil gas is 250°C; the dry distillation is also provided with a heat recovery operation; the dry distillation oil gas is passed into a fractionating tower for washing and heat exchange after dust removal; the dust removal equipment includes a gas-solid separator; the dry distillation oil gas is passed through the fractionating tower The dry distillation oil gas is cooled and heat-exchanged to 120°C by shale oil washing; 50% of the shale oil used for washing is returned to the bottom of the tower for cyclic washing after dust removal, and the remaining part is used as the product; the dry distillation oil gas after cooling is separated from the top of the tower during the distillation; the dry distillation oil gas after cooling is separated to obtain light oil, water and dry distillation gas; 80% of the dry distillation gas is returned as heat carrier dry distillation gas, and the remaining part is used as the product; the shale ash obtained by the dry distillation is subjected to secondary cooling and secondary utilization Use; the secondary cooling includes water-cooled wall tube cooling and circulating convection cooling in sequence; the pressure of steam in the wall tube after heat exchange in the water-cooled wall tube cooling is 1MPa; the temperature of shale ash after water-cooled wall tube cooling is 500℃; in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the high-temperature flue gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier; the temperature of the high-temperature flue gas is 900℃; the temperature of shale ash after the circulating convection cooling is 80℃.

[0070] The calorific value of dry distillation gas can reach 5000-6000kcal / Nm 3 ; The shale oil yield is 1 percentage point higher than that of the traditional Fushun furnace; The amount of wastewater generated is similar to that of the traditional Fushun furnace.

[0071] Comparative Example 2

[0072] This comparative example provides a shale dry distillation process, which comprises: heating the heat carrier dry distillation gas by fluidized heating of the solid heat carrier, and using the heated dry distillation gas as the gas heat carrier to dry distill the shale;

[0073] Wherein, the heat carrier retort gas is pressurized before heating; the solid heat carrier heats the heat carrier retort gas in a mixed heating tube and / or a fluidized heater; the temperature of the heated retort gas is 550°C; the retort gas is separated from the solid heat carrier by a separator after heating; the separator is a gas-solid separator; the solid heat carrier obtained by separation is reheated; 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 discharged after energy is recovered by a waste heat recovery system and then treated for environmental protection; the temperature of the flue gas is 700°C; the particle size of the shale is 3-80mm; the shale is dried before retort; the retort is countercurrent retort; the retort obtains shale ash and retort oil gas; the temperature of the retort oil gas is 350°C; the retort is also provided with Heat recovery operation; the dry distillation oil gas is washed and heat-exchanged by a conventional water washing process after dust removal; the dust removal equipment includes a gas-solid separator; the dry distillation oil gas is washed, dusted and cooled by a water washing process to obtain shale oil, sewage and dry distillation gas; 80% of the dry distillation gas is returned as a heat carrier dry distillation gas, and the remaining part is used as a product; the shale ash obtained by dry distillation is reused after secondary cooling; the secondary cooling includes water-cooled wall tube cooling and circulating convection 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 shale ash after the water-cooled wall tube cooling is 390℃; in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the high-temperature flue gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier; the temperature of the high-temperature flue gas is 900℃; the temperature of the shale ash after the circulating convection cooling is 70℃.

[0074] The calorific value of dry distillation gas is 5000-6000kcal / Nm 3 ; The shale oil yield is 1 percentage point higher than that of the traditional Fushun furnace; The amount of wastewater generated is similar to that of the traditional Fushun furnace.

[0075] Comparative Example 3

[0076] 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 the dry distillation gas is 3000-4000 kcal / Nm 3 ; The shale oil yield is similar to that of the traditional Fushun furnace; The amount of wastewater generated is similar to that of the traditional Fushun furnace.

[0077] Based on the results of the above embodiments and comparative examples, it can be seen that in the process provided by the present invention, since the energy of the high-temperature distillation gas comes from the heat exchange of the solid heat carrier, the distillation 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 distillation gas produced by the distillation process is increased and the quality is greatly improved, which will promote the entire distillation process to be more efficient and more environmentally friendly.

[0078] 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.

[0079] 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.

[0080] 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 shale distillation process, characterized in that: The process comprises: heating the heat carrier dry distillation gas by a solid heat carrier heated by fluidization, separating the dry distillation gas from the solid heat carrier through a separator after the heating is completed, reheating the separated solid heat carrier, generating flue gas in the reheating process, treating the flue gas as dry gas in a drying process after being treated by a waste heat recovery system, and using the heated dry distillation gas as a gas heat carrier to dry distill shale to obtain shale ash and dry distillation oil gas, which are passed into a fractionating tower for washing and heat exchange after dust removal, and the dry distillation oil gas is cooled and heat exchanged to 100-120° C. after shale oil washing, 50-80% of the shale oil used for washing is extracted from the bottom of the fractionating tower, and after cooling and dust removal, 50-80% of which is returned to the bottom of the fractionating tower for circulating washing, and the remaining shale oil enters a flash tower, and the shale oil at the top of the flash tower is mixed and diluted with the bottom oil before returning to the centrifuge, and the shale oil at the bottom of the flash tower is used as a product, and the shale ash obtained by dry distillation is reused after secondary cooling.

2. The process according to claim 1, characterized in that The heat carrier dry distillation gas is pressurized before being heated.

3. The process according to claim 1, characterized in that The solid heat carrier heats the heat carrier retorting gas in a mixing heating tube and / or a fluidized heater.

4. The process according to claim 1, characterized in that The temperature of the heated dry distillation gas is 500-550°C.

5. The process according to claim 1, characterized in that The separator is a gas-solid separator.

6. The process according to claim 1, characterized in that The reheating is performed in a reheater.

7. The process according to claim 1, characterized in that The reheating may also be achieved by adding heavy fuel or heat medium for heat exchange.

8. The process according to claim 1, characterized in that The temperature of the flue gas is 500-800°C.

9. The process according to claim 1, characterized in that The particle size of the shale is 3-80 mm.

10. The process according to claim 1, characterized in that The shale is dried before distillation.

11. The process according to claim 10, characterized in that The temperature of the drying gas in the drying process is 100-300°C.

12. The process according to claim 10, characterized in that The wet flue gas formed in the drying process is subjected to dust removal and condensation to recover condensed water.

13. The process according to claim 12, characterized in that The temperature of the wet flue gas is 50-150°C.

14. The process according to claim 10, characterized in that The heat source for the drying process is the waste heat recovered from heating the dry distillation gas.

15. The process of claim 1, wherein: The dry distillation is countercurrent dry distillation.

16. The process of claim 1, wherein: The temperature of the dry distillation oil gas is 200-350°C.

17. The process of claim 1, wherein: The dry distillation is also provided with a heat recovery operation.

18. The process of claim 1, wherein: The pressure difference between the dry distillation oil gas and the wet flue gas discharged from the drying section is 0.2-10 kPa, and the pressure of the wet flue gas is greater than the pressure of the dry distillation oil gas.

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

20. The process of claim 1, wherein: The dry distillation oil gas is introduced into the lower part of the fractionation tower.

21. The process of claim 1, wherein: In the fractionation, the top of the tower separates the cooled dry distillation oil gas.

22. The process of claim 21, wherein: The cooled dry distillation oil gas is separated to obtain light oil, water and dry distillation gas.

23. The process of claim 22, wherein: 80-95% of the dry distillation gas is returned as heat carrier dry distillation gas, and the rest is used as product.

24. The process of claim 1, wherein: The secondary cooling includes water-cooled wall tube cooling and circulating convection cooling performed in sequence.

25. The process of claim 24, 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.

26. The process of claim 24, wherein: The temperature of the shale ash after the water-cooled wall tubes are cooled is 400-500°C.

27. The process of claim 24, wherein: In the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the hot gas generated during the combustion process is transmitted to the reheater to heat the solid heat carrier, and then air is continued to be introduced to cool the shale ash.

28. The process of claim 24, wherein: In the circulating convection cooling operation, at least two circulating convection coolers are provided for switchable use.

29. The process of claim 27, wherein: The temperature of the hot gas is 700-1000°C.

30. The process of claim 24, wherein: After the circulating convection cooling, the temperature of the shale ash is less than 100°C.

31. The process according to any one of claims 1 to 30, characterized in that The process comprises: heating the heat carrier dry distillation gas by fluidized heated solid heat carrier, and using the heated dry distillation gas as a gas heat carrier to dry distill shale; Wherein, the heat carrier retort gas is pressurized before heating; the solid heat carrier heats the heat carrier retort gas in a mixed heating tube and / or a fluidized heater; the temperature of the heated retort gas is 500-550°C; after heating, the retort gas 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; the reheating is carried out in a reheater; the reheating also includes heat exchange by adding heavy fuel or heat medium; flue gas is generated during the reheating process; the flue gas is used as dry gas in the drying process after being treated by a waste heat recovery system; the temperature of the flue gas is 500-800°C; the particle size of the shale is 3-80mm; the shale is dried before dry distillation; the temperature of the dry gas in the drying process is 100-300℃; 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℃; the heat source of the drying process is the waste heat recovered from the heating of the dry distillation gas; the dry distillation is countercurrent dry distillation; the dry distillation obtains shale ash and dry distillation oil gas; the temperature of the dry distillation oil gas is 200-350℃; the dry distillation is also provided with a heat recovery operation; the pressure difference between the dry distillation oil gas and the wet flue gas discharged from the drying section is 0.2-10kPa, and the pressure of the wet flue gas is greater than the pressure of the dry distillation oil gas; the dry distillation oil gas is passed into the fractionation tower for washing after dust removal Heat exchange; the dust removal equipment includes a gas-solid separator; the dry distillation oil gas is introduced through the lower part of the fractionation tower; the dry distillation oil gas is cooled and heat-exchanged to 100-120°C after shale oil washing; the shale oil used for washing is extracted from the bottom of the fractionation tower, and after cooling and dust removal, 50-80% of it is returned to the bottom of the fractionation tower for cyclic washing, and the remaining shale oil enters the flash tower, and the shale oil at the top of the flash tower is mixed and diluted with the bottom oil before returning to the centrifuge, and the shale oil at the bottom of the flash tower is used as the product; the dry distillation oil gas after cooling is separated from the top of the fractionation tower; the dry distillation oil gas after cooling is separated to obtain light oil, water and dry distillation gas; 80-95% of the dry distillation gas is returned as the heat carrier dry distillation gas, and the remaining part is used as the product; the shale oil obtained by dry distillation The shale ash is recycled after secondary cooling; the secondary cooling includes water-cooled wall tube cooling and circulating convection 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 shale ash after water-cooled wall tube cooling is 400-500℃; in the circulating convection cooling, air is first introduced to burn out the carbon contained in the shale ash, and the hot gas generated during the combustion process is transmitted to the reheater for heating the solid heat carrier, and then air is continued to be introduced to cool the shale ash; in the circulating convection cooling operation, at least two circulating convection coolers are set for switchable use; the temperature of the hot gas is 700-1000℃; the temperature of the shale ash after the circulating convection cooling is less than 100℃.

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