Search

This paper aims to investigate the rapid pyrolysis characteristics of Huainan coal using a tube furnace. Influence of temperature on yields and compounds of tar and char are tested. The result shows that aliphatic chains break gradually with increasing pyrolysis temperature. This leads an increase in aromaticity. Maximum tar yields were obtained at about 550°C, the char yields decreased and the gas yields increased with the pyrolysis temperature. The tar was isolated to aliphatic hydrocarbon aromatic hydrocarbon, non hydrocarbon and asphaltene, and characterized by chromatography-mass spectrometry (GC/MS). The main content of tar include normal alkanes from C16-C30, two-,three- and four-ring aromatic hydrocarbons and alkyl-substituted hydroaromatic derivatives of polycyclic, phenols, indoles, quinines esters and others compounds.

Biomass oxygen-steam gasification associated with synthesis technology known as indirect biomass liquefaction is regarded as one of the most promising technologies of biomass utilization. In this paper, a comprehensive gasification model was developed for the simulation of rice straw oxygen-steam gasification using ASPEN PLUS. The gasification process was divided into two parts: pyrolysis and gasification. The RYield module was used to simulate the pyrolysis process with an external FORTURN program to calculate the pyrolysis products while the gasification process was calculated by the RCSTR module. With the help of the model, the gasification of rice straw was simulated under different residence time, different temperature and different amount of steam. The results showed that the proper residence time and temperature is 1.5s and 1300°C, respectively. The optimum amount of steam is steam/biomass=0.12 while the addition of oxygen is oxygen/biomass=0.2.

Experiments were performed to investigate the release behavior of potassium and sodium in the biomass high-temperature entrained-flow gasification with the addition of acid oxide SiO2, basic oxide MgO, amphoteric oxide Al2O3. The results showed that the volatilization of alkali was found to strongly depend on temperature. High gasification temperature strengthened the alkali release. When the reactor temperature was 1200°C, the volatilization of alkali species were about 37.87% for K and 71.14% for Na. Three additives all favored the retention of potassium and sodium and the content of water-soluble potassium and sodium in the ash. Among the three additives, MgO had the best retention effect. The potassium and sodium content in the gas phase was as low as 46.6% and 67.3% compared with raw straw, respectively. In the entrained-flow gasification with short residence time, the additives retained more alkali metals by the physical and chemical adsorption. Part of the additive utilized as physical adsorbent during the gasification enhanced the ash melting point of the residue carbon.