Externally heated oil shale destructive distillation process

Abstract

An externally heated oil shale destructive distillation process is characterized by comprising the steps that oil shale which is dried and allows external water to be removed enters an externally heated horizontal rotating destructive distillation furnace from a destructive distillation storage hopper for heat exchange with a heat pipe, destructive distillation product semicoke and destructive distillation gas are fed into a gas-solid separation chamber simultaneously, solid semicoke is fed into a combustion furnace to be combusted, generated shale ash is discharged from the bottom of the combustion furnace, generated high-temperature flue gas is fed to the exterior of the externally heated horizontal rotating destructive distillation furnace for heat exchange with the heat pipe, and drying and dewatering are conducted on oil shale raw ore fed from the tail of the externally heated horizontal rotating destructive distillation furnace to a drying chamber under residual temperature of flue gas; gas in the gas-solid separation chamber is fed into a cooling recovery system for condensate recovery of shale oil, uncondensed gas is fed into the combustion furnace to be combusted, and generated flue gas is fed to the exterior of the externally heated horizontal rotating destructive distillation furnace for heat exchange or is fed into a nozzle located outside the externally heated horizontal rotating destructive distillation furnace to be combusted to generate high-temperature flue gas for heat exchange with the heat pipe.

Description

technical field [0001] The invention relates to the technical field of oil shale dry distillation, in particular to an external heating type oil shale dry distillation process. Background technique [0002] Oil shale is a kind of sedimentary rock, which contains kerogen in its mineral skeleton. Oil shale is isolated from air and heated to about 500°C, and kerogen is pyrolyzed into shale oil. This process is called oil shale dry distillation, and dry distillation produces Semi-coke and shale oil and gas, the world's oil shale resources are abundant, and its reserves converted into shale oil are as high as more than 400 billion tons. my country's oil shale resources are predicted to reach 719.9 billion tons, which is 47.6 billion tons converted into shale oil. It has not yet been exploited on a large scale and can be used as an alternative resource for conventional energy such as coal. [0003] Domestic oil shale carbonization mainly adopts the vertical gas heat carrier carboni...

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Problems solved by technology

Foreign technology is relatively mature, such as Galoter furnace, but it still has many shortcomings such as dust in the retort gas after retort, resulting in more mechanical impurities in shale oil, which cannot meet the qualified standards

The externally heated horizontal rotary retort furnace was used to manufacture a horizontal rotary externally heated retort furnace from 1931 to 1961 in the Estonian oil shale refinery, but it was eliminated due to low heat transfer efficiency and low processing capacity, and it is still used in China External heat dry distillation technology decomposes rubber waste such as tires, but the processing capacity of a single unit is still low and the heat transfer efficiency is low

As for the external heat dry distillation process (such as ATP furnace), the heat source is isolated from the oil shale, and the heat is indirectly transferred to the oil shale. There is no successful case of external heat dry distillation oil shale at home and abroad.

[0005] The heat conduction method of the externally heated horizontal rotary retort furnace is that the gas heat carrier first heats the outer wall of the horizontal retort retort furnace, and then conducts heat exchange with the oil shale in contact with it. This method of heat transfer is inefficient, and the retort time is long. The amount of material is small; in addition, the residence time of the gas heat carrier between the cylinder wall of the horizontal rotary retort furnace and the fixed shell is too short, resulting in the heat being discharged from the fixed shell before being completely transferred to the oil shale, and the heat is not fully utilized , greater heat loss

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