Experimental Research And Quantum Chemical Analysis Of Biomass Gasification In Circulating Fluidized Bed

Biomass gasification electricity generation is an important efficient biomass utilization technology.Circulating fluidized bed technology is suitable for large-scale gasification project as its materials'adaptability and high heat transfer efficiency.The mechanism of biomass pyrolysis and gasification was investigated through a fluidized-bed steam gasification experiment,TGA experiment on TG-FTIR analyzer and quantum chemistry methods.A series of experiments was investigated to explore the impact on the production of gas and tar during the process of gasification of steam/biomss and bed material in a fluidized bed gasifier.Results illustrate that hydrogen content,gasification efficiency and reduction of tar were in positive correlation with temperature and steam to biomass?S/B?ratio.The content of some components in tar like toluene,styrene and phenol was significantly affected by gasification conditions.Dolomite has the highest catalytic efficiency,but olivine is more suitable for fluidized bed compared with quartz sand and dolomite because it's catalytic properties and abrasion resistance.Medium calorific syngas with 34%hydrogen content and no more than 20g/m³ tar content could be obtained under the gasification conditions of 800?,S/B ratio at 0.9 and using olivine as the bed material.Cotton stalks sample was pretreated with deionized water and acid wash,and was investigated by thermal gravimetric analysis through TG-FTIR analysis system.Results show that the pyrolysis of cotton stalk was divided into pyrolysis zone and negative pyrolysis zone.Alkali and alkaline elements could affect the formation of the char and the release rate of the gas products during pyrolysis,and increase the sensitivity of biomass pyrolysis through reducing the activation energy of the cotton stalks.Eight possible pyrolytic pathways of the lignin model compound phenethyl phenyl ether were calculated using density functional theory?DFT?methods by Gaussian software at B3LYP/6-31G?d?basis sets.The results of thermodynamic and surface potential energy analysis show the main pyrolytic pathway and the activation energy barrier of rate-limiting steps.The influence of metal ions Mg²⁺during biomass pyrolysis was investigated as the form of metal complexes.The calculation results demonstrate that addition of metal ions Mg²⁺could reduce the activation energy barrier of bond cleavages in phenethyl phenyl ether and promote the pyrolysis reaction proceeds.