Modelling of a downdraft gasifier fed by agricultural residues

A non-stoichiometric model for a downdraft gasifier was developed in order to simulate the overall gasification process. Mass and energy balances of the gasifier were calculated and the composition of produced syngas was predicted. The capacity of the modeled gasifier was assumed to be 0.5 MW, with an Equivalence Ratio (EQ) of 0.45. The model incorporates the chemical reactions and species involved, while it starts by selecting all species containing C, H, and O, or any other dominant elements. Olive wood, miscanthus and cardoon were tested in the formulated model for a temperature range of 800-1200 °C, in order to examine the syngas composition and the moisture impact on the supplied fuel. Model results were then used in order to design an olive wood gasification reactor.     

Ecological and Economic System Health Assessment Based on Fuzzy Set Pair Analysis： A Case Study of Northwest Region, China

Due to the increasingly serious environmental pollution and destruction,especially humans’ unreasonable activities,the ecological and economic system(EES) issues of Northwest region in China have attracted more and more attention of the researchers.Aiming at evaluating its ecological and economic system health,a multi-objective evaluation framework called PressureState-Response(PSR) was established to describe the ecological and economic health situations.Meanwhile,an integrative set pair model combining set pair analysis(SPA) and fuzzy analytic hierarchy process(FAHP) was proposed to assess the ecological and economic system.Then the EES status of five northwest provinces(Shanxi,Gansu,Qinghai,Ningxia and Xinjiang) of Northwest region in China was evaluated during 1985 to 2009.The EES development trends of five provinces are obtained.In general,the health values of five provinces showed a rising trend.The health values of five provinces grew rapidly during 1985 to 2000.After 2000,the health values of five provinces still followed the present growth trend,but the growth is relatively smooth.The results show that the method proposed is effective for assessing the health of ecological and economic system.     

Ecological and Economic System Health Assessment Based on Fuzzy Set Pair Analysis: A Case Study of Northwest Region,China

Abstract

Due to the increasingly serious environmental pollution and destruction, especially humans’ unreasonable activities, the ecological and economic system (EES) issues of Northwest region in China have attracted more and more attention of the researchers. Aiming at evaluating its ecological and economic system health, a multi-objective evaluation framework called Pressure- State-Response (PSR) was established to describe the ecological and economic health situations. Meanwhile, an integrative set pair model combining set pair analysis (SPA) and fuzzy analytic hierarchy process (FAHP) was proposed to assess the ecological and economic system. Then the EES status of five northwest provinces (Shanxi, Gansu, Qinghai, Ningxia and Xinjiang) of Northwest region in China was evaluated during 1985 to 2009. The EES development trends of five provinces are obtained. In general, the health values of five provinces showed a rising trend. The health values of five provinces grew rapidly during 1985 to 2000. After 2000, the health values of five provinces still followed the present growth trend, but the growth is relatively smooth. The results show that the method proposed is effective for assessing the health of ecological and economic system.     

焦化废水处理利用的复合生态工程系统实验

生态工程系统(EES)处理焦化废水是实现低成本废水资源化的有效手段。该EES由UASB ABS IWBE组成。结果表明：在HRT为30h时，该系统对废水COD去除率的均值是91．1％，对NH4-N去除率平均为99．5％，对酚去除率平均为99．8％。废水可达标排放或循环利用。     

湖南资阳区生态经济社会系统协调度评价研究

构建和谐社会已经成为人类社会发展的主流方向，以区域农业系统为研究对象，在构建了系统评价的协调度函数、协调等级和评价指标体系的基础上．从生态经济社会子系统三个层次及系统层次上分析了湖南省益阳市资阳区1995-2002年区域农业系统协调度的变化趋势。研究结果表明：资阳区从1995-2002年区域农业系统处于低度失调与弱度失调状态，协调等级为4-5，协调度变化处于缓慢上升趋势。经济子系统的协调度表现较快增长趋势，协调等级从3上升到7；社会子系统协调度表现U型变化趋势，协调等级为4-3-4；生态子系统协调度表现较大的下滑趋势。协调等级从7级下降到4级。经济子系统在系统的协调度增长中发挥了重要的作用。资阳区在强调经济发展的同时应该加强环境建设和重视社会建设。以推动区域农业系统的协调发展。