餐厨垃圾制生物煤试验初探

Experimental study on making bio-coal from food waste by hydrothermal carbonization

文章以校园餐厨垃圾为原料，以水热炭化的方法处理餐厨垃圾，对得到的水热炭化固体产物生物煤的特性参数进行测定，得出生物煤的热值及灰分均达到GB／T17608—2006精煤的一级标准。通过3水平3因素正交试验，对水热炭化工艺条件进行优化，得到影响因素的主次顺序为温度〉pH〉反应时间，合适的工艺条件为180℃，pH为4，反应时间为3h。在温度160—220℃范围内，随着反应温度的增高，生物煤的热值增加，而其转化率则是先增高，后趋于平缓，最后急速下降。在优化工艺条件下对餐厨垃圾进行水热炭化，得到生物煤热值为30．18MJ／kg，转化率为54．08％。对餐厨垃圾及优化条件下得到的生物煤进行元素分析，得出经过水热炭化后，碳的质量百分含量从49．00％提高到65．93％，而氧元素的质量分数降低了17．98％。同时，水热炭化改变了餐厨垃圾的极性及芳香性。

Hydrothermal earbonization（HTC） is a chemical conversion method, which can deal with waste biomass into valuable resources in proper reaction conditions. In this study, campus food waste was used as raw material, a coal-like solid was gained by hydrothermal carbonization, known as bio-coal. According to the measured parameters of bio-coal, the calorific value and ash of bio- coal reached the clean coal standard GB/T 17608-2006. Influence of temperature, pH and reaction time on hydrothermal carbonization of food waste were studied through a three-level and three- factor orthogonal test, in which the affecting order of the factors and optimal technological condi- tions were confirmed. The results showed that the appropriate hydrothermal carbonization condi- tions were temperature 180 ℃, pH 4, reaction time 3 h and affecting order of the factors is temper- ature, pH, reaction time. The calorific value and yield of bio-coal were different while the temper- ature range among 160-220 ℃. When the temperature arising, the calorific value increased, but the yield was firstly increased （160-180 ℃）, then leveled off （180-200 ℃）, and finally fell sharply （200- 220 ℃）. The calorific value was 30.18 MJ/kg, and the yield was 54.08% while carbonized under op- timized condition. Elemental analysis of food waste and bio-coal showed that the mass percentage of carbon content increased from 49.00% to 65.93%, while the element of oxygen mass fraction was reduced by 17.98%. Meanwhile, after the hydrothermal carbonization, the aromaticity increased and the polarity decreased.