Papers by Author: Xiao Xu Fan

Abstract: In this paper, the combustion characteristics of palm kernel meal were investigated in a circulating fluidized bed (CFB 100)(height=3000mm, inner diameter=100mm). The results showed that the temperature and pressure of the furnace were relatively steady. The contents of SiO2, Na2O and K2O of the bed material ranged smoothly with the process, the particle size of the bed material fluctuated slightly. The alkali metal contents of bed material were ranged from 1.5% to 3.5%.

Abstract: Using the Gidaspow model as the momentum exchange coefficient to take a full-loop simulation of miniature circulating fluidized bed gasifier (CFBG) in the lab, and taking mutual influence of different parts in consideration, it focus on the gas-solid flow structure in the riser in this paper. The heterogeneous behavior in the CFBG riser and the radial profiles of solid volume fraction under different solid inventories in simulation are showed in this paper as a replenishment of certain data which are hard to measure in experiments. The results showed it can’t form an obvious core-annulus flow because of the riser’s high height-diameter ratio and the big refeed line diameter. There are clusters growing and dissipation in a short time. A turning point of pressure drop may be seem as a separation of dense area and dilute area.The three-dimensional (3D) simulation revealed the solid flux and the pressure drop agree with the experimental data.

Abstract: The fuel characteristics of municipal sewage sludge are suitable for dual fluidized bed(DFB) gasification, which can get middle calorific value gas through volatile pyrolysis, and reduce volume through char combustion. The hot test results of municipal sewage sludge on DFB rig were showen that the temperature distribution along combustor heigh is uniform, and the carbon content of fly ash is about 2~3%. In the experiment, with the increase of gasifier temperatrue, the more volatile of the sewage sludge was pyrolyzed. When the temperature of the gasifier reached 800°C, the calorific value of gas was 6.9MJ/Nm3; the emissions of SO₂, NO_x and HCl were appropriate to the standard. The leaching toxicity of heavy metal of the fly ash was lower than the discharge standard.

Abstract: Because of quite a certain content of alkali metal in biomass, bed material agglomeration appears in the process of thermal reaction in fluidized bed, which can destroy fluidization. In the paper, fluidized bed gasification experiments on alkali metal enrichment were made, of which cotton straw pellets were used as fuel. The results are shown that experiments could keep running by bed material replaced at regular time without slag and the component of the bed material maintained stability. The replaced bed material could be used again after being washed. Through the XRF analysis, it could be found that the potassium compound with high dissolubility could be removed by washing.