Recently, Xu Guangwen's research team at the Institute of Process Engineering of the Chinese Academy of Sciences made use of jet pre-oxidation gasification technology to make new progress in the treatment of cohesive coal. Paper Pilot Study on Jetting Pre-oxidation Fluidized Bed Gasification Adapting to Caking Coal was published in Applied Energy, 2013, 110, 276-284.
In a conventional fluidized bed gasifier, the cohesive coal is easily agglomerated and affects the normal operation of the gasifier. To this end, the Chinese Academy of Sciences proposed the use of jet pre-oxidation fluidized bed gasification technology to process the coking coal.
This technology uses oxygen-containing gas to rapidly transport cohesive coal particles (grain size less than 5mm) to the high-temperature dilute phase zone in the fluidized bed and disperse it rapidly, while using the oxidation of oxygen-containing gas to treat coal particles. Thermoplastic material. The pre-oxidized weakly cohesive semi-coke falls into the dense phase zone within the fluidized bed and reacts with the gasification agent (containing O2, CO2, water vapor). Based on the above principle and after fully verifying the applicability of the process to the cohesive coal in laboratory equipment, a small test apparatus with a treatment capacity of 150 kg/h was established.
Figure 1: Fluidized bed pre-oxidation fluidized bed gasification principle and pilot test flow chart
The test successfully succeeded in air and oxygen-enriched coal particles with a bonding index of 20, and the calorific value of the generated gas varied within the range of 2.9-5.0 MJ/Nm3. Studies have shown that the oxygen supply of the raw material delivery system is too high to burn part of the gasification gas, thereby reducing the calorific value of the generated gas. The oxygen supply for the best raw material delivery system is 37% of the total oxygen supply for gasification. Experiments have found that increasing the oxygen concentration in the dense phase gasification agent to 30% will greatly increase the gasification rate and carbon conversion rate of the low active coal.
Table 1: Jet Pre-oxidation Fluidized Bed Gasification Small Test Conditions and Results
A: a1, a2 indicated the excessive air ratios calculated for the total gasification agent, fuel jetting gas, bottom fluidizing gas excluding steam, respectively.a = a1 + a2.
The results of laboratory basic research and small-scale experiments fully verified the applicability and feasibility of jet pre-oxidation fluidized bed gasification technology for the treatment of cohesive coal, providing theoretical basis and technology for the further development of the technology and process amplification. The support provides an important technical route for the comprehensive cleaning and utilization of cohesive coal.
The above work was supported by the National Science and Technology Support Project (2009BAC64B05) and the Scientific and Technological Pilot Project of the Chinese Academy of Sciences (XDA07050400).
Jinwu Glass Fiber Co., Ltd , https://www.jinwuwindows.com