Oil shale rotary kiln dry distillation and circulating fluidized bed combustion process

Abstract

An oil shale rotary kiln dry distillation and circulating fluidized bed combustion process makes organic combination of a rotary kiln dry distillation with a circulating fluidized bed; oil shale particles are mixed with thermal-cycle ash from a circulating fluidized bed boiler and part of circulating fluidized bed boiler bottom ash, and then are sent into a rotary kiln for dry distillation to prepare shale oil and dry distillation coal gas; the dry distillation coal gas has a high calorific value; a part of the coal gas is used as recycle wind of a semicoke material recycle device, and enters the circulating fluidized bed boiler with oil shale semicoke particles for combustion, and the residual part is delivered into an internal combustion engine for combustion generation. The invention can increase shale oil and coal gas quality, reduce energy loss and environment pollution, and improve the comprehensive utilization degree.

Description

technical field [0001] The invention relates to an oil shale rotary kiln dry distillation and circulating fluidized bed combustion process, in particular to two systems using a circulating fluidized bed as the heat source of the dry distillation furnace and shale ash as the heat carrier of the rotary kiln dry distillation furnace, which can realize The all-round comprehensive optimal utilization of oil shale resources in oil refining, heat supply, power generation, and building materials belongs to the technical field of oil shale resource utilization. The process is also applicable to coal and biomass. Background technique [0002] Oil shale is a combustible organic mineral with fine bedding, high ash content, and low calorific value. Low-temperature dry distillation can obtain shale oil similar to natural petroleum. The world is rich in oil shale resources. If converted into calorific value, its reserves rank second only to coal among fossil fuels; if converted into shale...

AI Technical Summary

Problems solved by technology

Therefore, there are following disadvantages: one is to deal with massive shale, the retort time is quite long, generally 12 to 24 hours, and the particle size is large, many large particles cannot be completely retorted, so the retort efficiency is low, the oil yield is low, The resource utilization rate is low; the second is to use thermal cycle dry distillation gas as the heat carrier, and usually use external heat sources such as regenerative heating furnaces to heat the gas, that is, first burn the gas in the regenerative heating furnace to heat the furnace body, and then heat the cold The gas is sent into the heating furnace to transfer the heat of the furnace body to the cold gas, and after heating, it is sent to the carbonization furnace to heat the oil shale carbonization, so not only consumes a lot of gas and wastes energy, but also the temperature of the carbonization hot gas is always changing, resulting in carbonization The temperature in the furnace changes periodically, the oil output is unstable, and the oil yield is low; third, if the oil shale semi-coke obtained by dry distillation continues to be used as boiler fuel, it must be cooled first and then further crushed to meet the requirements of boiler combustion. Semi-coke must be cooled with water first, then dried, and then crushed, so it consumes a lot of energy

However, the purpose of this type of carbonization furnace is single at present, and an additional combustion furnace is needed to burn shale semi-coke into high-temperature shale ash as a solid heat carrier, and the remaining semi-coke and ash are discarded in large quantities

Since the combustion furnace is only used to generate solid heat carrier, it cannot achieve the purpose of power generation and heat supply

[0007] However, circulating fluidized bed boilers are mainly used for combustion power generation and heat supply to obtain higher combustion efficiency and thermal efficiency. At the same time, circulating fluidized bed boilers are low-temperature combustion, and limestone can be added to the furnace for desulfurization, and nitrogen can be reduced due to low-temperature staged combustion. The discharge of oxides can achieve clean combustion, but the disadvantage of using oil shale directly for combustion in circulating fluidized bed boilers to generate electricity and heat is that the shale oil refining process is omitted and the oil resources in oil shale are burned

Images