The Fundmental Research On The Catalytic Liquefaction Of Paulownia In Water

With the increasing depletion of limited fossil fuels and the rapid growth of global energy consumption, it is of great significance to research and make use of biomass energy. Biomass energy attracts the worldwide attention as it is a renewable energy which can be liquefied directly. So, it is of great value on academic theory and engineering application to do the basic research on paulownia catalytic liquefaction with water as the reaction medium.The oil product rate and the rate of paulownia direct liquefaction in water are affected by many factors. Paulownia direct liquefaction is processed in a 1L batch autoclave with water as a solvent. And the reaction temperature, residence time and liquid ratio are investigated by the pre-experiment design. At the pre-experiment conditons, the best and most economical condition for the purpose to get the maximum heavy oil yield is that the reaction temperature is 300℃, residence time is 10 min and liquid ratio is 6.This provides a reference for the determination of experimental conditions of paulownia direct liquefaction in water. Then the affection law of reaction temperature, residence time and the amount of iron powder or soda catalyst is investigated through the single factor optimization. It is found that the heavy oil rate and light oil rate are significantly improved while the solid residuse rate reduced when catalyst is added. The maximum heavy oil rates of paulownia direct liquefaction are 31.92% and 36.34% with homogeneous sodium carbonate solution and non-homogeneous reduced iron powder catalysts, respectively. Both are significantly higher than 27.01% obtained without catalyst. While the minimum residue rate is 7.23% with homogeneous sodium carbonate solution catalyst and 8.12% with non-homogeneous reduced iron powder catalyst. Both are significantly lower than 18.67% obtained without catalyst. The gas products of paulownia direct liquefaction are analyzed qualitatively and quantitatively by gas chromatography, and it is found that the gas products are mainly composed of about 90% of the volume fraction of CO2, and also contain about 9% of CO and 1% of CH4. The bio-oil products are complex and have a wild range of compounds. The influence of the reaction conditions is researched on the group structures of the products when the solid residues and liquid bio-oil are analyzed by Fourier transform infrared spectroscopy. The volatile component of bio-oil are qualitative and quantitative analyzed using GC analyzer and it is found that the light oils are mainly composed of phenols, ketones, fatty acids and aromatic acids, furan derivatives, esters and aldehydes while the heavy oils mainly contain phenolic derivatives, high molecular weight ketones, fatty acids, aromatic acids, esters, benzene derivatives and aldehydes. The qualitative and quantitative analysis results of bio-oil provide the fundamental information for its comprehensive applications in the chemical and energy industry.Thermodynamic and kinetic properties in the process of biomass conversion are required for the development and design of biomass liquefaction technology. Thermodynamics and reaction mechanism of hydrolysis on the process of paulownia direct liquefaction in water are calculated and simulated. If we assume the light oil as the initial product A, the heavy oil as intermediate Q while the gas, water and residues as final product P, and then paulownia direct liquefaction process in water can be seen as a series of single component consecutive reactions. By calculating the first and the second step reaction rate of the process, we can know the mechanism of paulownia liquefaction is that the first step to produce heavy oil is fast reaction and the second step to produce gas, water and solid residues is slow reaction which determines the whole reaction rate.