温室生物质发酵酿热的碳氮水耦合调控效应研究

Coupling regulation of multi-parameters on heat recoveryfrom greenhouse waste composting

最大限度利用可再生能源并减少调控成本,是温室生物质发酵高效酿热产能的基础,也是温室生产可持续发展的核心。以麦秸为原料,牛粪为辅料,以初始物料容重(Bulk Density,BD)、碳氮比(Carbon Nitrogen Ratio,C/N)和含水率(Moisture Content,MC)为研究因素,利用响应面法研究因素间交互作用的优势。试验为三因素五水平设计,设置23个处理,以升温速率、产热速率、热能转化率和总有机碳降解率为发酵评价目标,基于TOPSIS法建立综合评价体系,用熵权法合理确定各指标权重,构建了多因素耦合下生物质发酵酿热的响应模型,解析了碳氮水多因素耦合对生物质发酵酿热的综合作用规律。结果表明,单因素效应中综合评分与C/N值呈近线性关系,与BD和MC值均呈凸型二次曲线关系;BD、MC和C/N协同影响综合酿热效果评价值。当BD、C/N和MC分别为0.05~0.07 g·cm^(-3),38.30~38.40,52.94%~59.83%时,综合评价值存在最优区间,将所得发酵因素综合调控下的最优方案应用于冬季延安地区的温室采暖,可使该地区大跨度非对称塑料温室夜温提高0.94~1.50℃。

Maximizing the use of renewable energy and reducing regulation costs are the basis for efficient greenhouse heating from biomass composting and the core of sustainable development of greenhouse production.In this study,wheat straw was used as raw material and cow dung as auxiliary material,and initial material bulk density(BD),carbon nitrogen ratio(C/N)and moisture content(MC)were taken as research factors.The response surface methodology was employed to examine the advantages of interaction among factors.The composting evaluation targets were the heat rate,heat production rate,heat energy conversion rate and total organic carbon degradation rate.Based on the TOPSIS method,a comprehensive evaluation system was established.The entropy weight method was used to reasonably determine the weight of each index,and the response model of biomass composting heat generation under multi-factor coupling was constructed,and the comprehensive effect of carbon,nitrogen and water multi-factor coupling on biomass fermentation heat brewing was analyzed.The results showed that when other factors were at the intermediate level,the comprehensive score showed a nearly linear relationship with the increase of C/N,and convex quadratic curve relationships with the increase of BD and MC.BD,MC and C/N synergistically affected the comprehensive composting process.When BD,C/N and MC are 0.05~0.07 g·cm^(-3),38.30~38.40,52.94%~59.83%,respectively,the comprehensive evaluation value had an optimal interval.The optimal scheme of the obtained compositing factors was applied in winter,the nighttime temperature increased by 0.94~1.50℃in the large-span asymmetric plastic greenhouse in Yan’an area.