Biorefinery And Economic Analysis Of Xanthoceras Sorbifolia

Xanthoceras sorbifolia, a good woody oil plant in Northern China, has been determined as one of the most promising raw materials of biodiesel and taken priority to develop by the goverment. Producing biodiesel using Xanthoceras sorbifolia leads to formation of several by-products with economical potentials, such as husk, seed coat, kernel residues, crude glycerol. If those by-products are not developed and utilized rationally, it will cause a huge waste of resources. In this paper, in order to solve the current problems of utilization of Xanthoceras sorbifolia, the biorefinery and multi-product coproduction processes which give full consideration to the use of other by-products in addition to biodiesel production was explored and investigated to provide some scientific guidances and technical supports for the comprehensive development and utilization of Xanthoceras sorbifolia.Firstly, the composition of different parts of Xanthoceras sorbifolia fruit was determined. The possibilities for production of biodiesel from kernel oil of Xanthoceras sorbifolia and production of medicinal saponins, cellulosic ethanol,1,3-propanediol, crude proteins from residues of Xanthoceras sorbifolia and by-product glycerol of biodiesel were explored through preliminary experiments. It showed that those key processes were feasible. On the basis, a process flowsheet of biorefinery using Xanthoceras sorbifolia was proposed, through which biodiesel, bio-based chemicals and saponins were coproduced. The feasibility of integration among the processes for production of cellulosic ethanol, production of biodiesel, extraction of saponins and aqueous two-phase extraction of 1,3-propanediol was verified through material balance analysis for the biorefinery process.Secondly, a three-liquid-phase extraction system (TLPS) composed of n-hexane /ethanol/ammonium sulfate/water was investigated to separate saponins, oil and proteins in kernel of Xanthoceras sorbifolia simultaneously. The effects of the radio of ethanol and ammonium sulfate, concentration of n-hexane and adding order of the different components of TLPS were investigated. A better condition of TLPS was obtained:25%(w/w) n-hexane, 25%(w/w) ethanol,25%(w/w) ammonium sulfate and 25%(w/w) water. In this system, kernel oil was enriched in the top phase (n-hexane phase) with a yield of 87%, while kernel saponins were mainly in the middle phase (ethanol phase) with a recovery of 83.5%, proteins were enriched in the interface between the top and middle phase, which could be recovered by filtration. The results revealed that TLPS of n-hexane/ethanol/ammonium sulfate/water could simultaneously separate three components of Xanthoceras sorbifolia kernel. This simple process is a effective method for multi-product coproduction.Finally, the technical and economic analysis of the biorefinery process which was based on 300,000 tons Xanthoceras sorbifolia per year design was investigated through calculation of the material and energy consumption on the basis of feasible experiments and developmental status of the key process in biorefinery and multi-product coproduction. And the main factors and laws which affected the biorefinery cost were obtained. The analysis showed that raw material costs and utility costs were the most important factor for the multi-product coproduction process, which accounted for over 80% of the total cost in total. Breakdown of the costs according to production process, the cost of cellulosic ethanol production was the most important process costs, nearly 50% of the total cost. The sensitivity ananlysis showed that the cost of cellulosic ethanol production was the key factor influencing the profit, followed by the cost of utility. Energy integration among the various processes of the biorefinery and multi-product coproduction is expected to reduce costs, while the costs can be further reduced when the technology for cellulosic ethanol production reaches such a perfect degree.