PDF《城市干污泥与水葫芦的混燃特性分析》

accepted

31 December

2015 Abstract: The combustion characteristics of dry sludge, water hyacinth and their blends in Guangzhou were investigated under different combustion conditions by thermogravimetric analysis (TGA). The kinetic equation of each sample was established by using the TG?DTG curves. Results obtained from TGA tests indicated that there were four combustion steps for sludge samples, i.e. moisture exhalation, exhalation of main volatile, exhalation of minor volatile and fixed carbon combustion, and residues decomposition. Thermal tests of water hyacinth were corresponding to moisture exhalation, exhalation of main volatile, fixed carbon combustion and residues decomposition. Thus, volatile exhalation stage was considered as the dominating step of the combustion in this experiment. After adding 10% ~ 40% of the water hyacinth, the ignition point Ti of mixed sludge increased slightly.The combustion performance was improved with volatile characteristic index D and comprehensive combustion characteristic index S increased by 0.22 ~ 1.06 and 0.10 ~ 0.92 times, respectively. Both volatile exhaling and combustion behavior levels in sludge acted intensively with water hyacinth addition, which illustrated a synergistic interaction and co?combustion of sludge and water hyacinth. In comparison with the ambient air, combustion characteristics of mixtures were restrained in the oxy?fuel environment with V(CO2 ) / V(O2 ) of

8 / 2. The corresponding kinetics parameter (Em ) was calculated by using Coats?Redfern equation calculations. Em of the sludge, water hyacinth, and their blends were in the range of 32.09 ~ 34.70 kJ ・mol-1 , 30.56 ~ 51.63 kJ ・mol-1 , and 22.44~28.40 kJ ・ mol-1 , respectively. The activation energy decreased with the addition of water hyacinth as represented by the increase of comprehensive combustion index in the blends. Thus, the reaction orders of pre?peak of the first volatile combustion can be described as n = 0.5, while the post?peak and 环境科学学报36 卷other peaks were both suggested as n = 2. Keywords: sewage sludge;

water hyacinth;

combined firing;

thermogravimetric analysis;

combustion characteristics;

kinetics model

1 引言(Introduction) 随着污水处理厂的提标升级及污水处理技术 的不断深化,污泥产量大幅增加,同时浓缩在其中 的有毒有害物质种类和数量也随之增多.据统计,目 前我国每年产生污泥约 3*107 t(含水率以 80%计), 其中,80%的污泥没有达到稳定........