Graded gasification method and device

Abstract

The invention relates to a graded gasification method and device, and the graded gasification method comprises the following steps of: introducing fuel B and a first gasifying agent A into a primary gasification unit for a gasification reaction to generate a gas-solid mixture C and bottom slag K; carrying out gas-solid separation on the gas-solid mixture C to form primary coal gas E and hot semicoke D; feeding the hot semicoke D and a second gasifying agent F into a first reactor for reaction to generate a mixture G; feeding the mixture G and the primary coal gas E into a heat exchange reactorto complete a heat exchange reaction to generate solid bottom slag L and final coal gas H, and completing graded gasification. Sensible heat of a high-temperature reactor product is fully utilized topromote cracking of primary gas tar and conversion of carbon, and the gasification performance of the system is improved.

Description

technical field [0001] The invention relates to the technical field of gasification, in particular to a gasification device and method for carbonaceous raw materials, in particular to a hierarchical gasification method and device. Background technique [0002] Coal gasification technology is an important part of clean coal technology and one of the main ways to use coal efficiently and cleanly. It has become the core technology of many modern energy and chemical systems. Fluidized bed gasification can achieve good back-mixing and contact between gasification agent and fuel, and can use wide-screened crushed coal particles as fuel, and the coal type has strong adaptability; however, fluidized bed gasification is limited by the fluidization of particles. Due to limited conditions, it can only be operated below 1000°C, and the gasification reaction rate is low, resulting in a low carbon conversion rate. The entrained bed coal gasification process has high reaction temperature,...

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Problems solved by technology

[0004] (1) For example, the products generated by the reaction of the primary gasification unit are first separated to form the first gas flow and the second gas flow, and then the first gas flow and the second gas flow are respectively sent to the secondary gasification unit for staged reaction , is conducive to improving the gasification efficiency, but the semi-coke content ratio between the first gas flow and the second gas flow is too small, and a large amount of fly ash exists in the second gas flow, which cannot react with the gasification agent, which will directly affect the system. gasification performance, especially when the secondary gasification unit is operating under solid slagging conditions

[0005] (2) The gas holdup and solid holdup in the first gas flow and the second gas flow are crucial to the rapid formation of the high-temperature reaction zone in the secondary gasification unit and the carbon conversion rate of the system, which is not proposed in the prior art Control measures for the above-mentioned gas holdup and solid holdup

[0006] (3) In the existing entrained entrained bed technology, there are measures to quench the high-temperature slag with cold gas, water quench or waste heat boiler to cool the slag, but it cannot solve the problem of tar and residual carbon contained in the initial coal gas in the staged gasification The problem is that high-temperature sensible heat cannot be effectively used, and there are also problems such as complex systems and waste water

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