Abstract:

The excessive accumulation of excavated waste in landfills can lead to environmental pollution of the surrounding soil, groundwater, and air. Due to the similarity in composition between excavated waste and municipal solid waste, co-gasification is an efficient method for the clean disposal of excavated waste. The product distribution and syngas component characteristics of the co-gasification process were explored under different gasification temperatures and blending ratios, and the synergistic effect of co-gasification was analyzed. Through gasification evaluation index calculation and response surface simulation, the blending ratios and gasification temperatures were optimized. The results indicated that increasing the gasification temperature promoted the decomposition of solid residue into gas and improved gas production rates. Experimental values of the solid residue of the blends at a gasification temperature range of 700—1000℃ were lower than the linear additive values of the gasification of a single raw material, demonstrating a positive synergistic effect on promoting the transformation of solid coke through the co-gasification of blends. The high content of H₂ and CH₄ in syngas suggested that excavated waste had positive gasification characteristics. Experimental yields for each component in syngas were higher than calculated values at 900℃ and 1000℃, indicating that higher gasification temperatures promoted syngas generation. The gasification evaluation index as well as carbon conversion rate significantly increased with the increase of blending ratio of excavated waste and gasification temperature. Under the gasification temperature of 1000℃, the calorific value and gasification efficiency of syngas reached the maximum value when the blending ratio of excavated waste was 60% and 80%, respectively. The maximum H₂ (188.44mL/g) and CH₄ (104.22mL/g) yields were obtained for single gasification of excavated waste at 1000℃, but CO yields also reached the maximum value within this condition. When the blending ratio of excavated waste was in the range of 60%—89% and the gasification temperature was close to 1000℃, the content of H₂ and CH₄ in syngas product of blends was higher, and meanwhile higher calorific value, carbon conversion rate and gasification efficiency of syngas could be obtained. This study provides the basis for the research and application of the co-gasification technology of excavated waste and municipal solid waste.

Key words: excavated waste, municipal solid waste, syngas components, synergistic analysis, simulation optimization

摘要：

垃圾填埋场中陈腐垃圾的过量积累会对周边土壤、地下水和空气造成环境污染。由于陈腐垃圾与原生垃圾组分的相似性，将陈腐垃圾与原生垃圾共气化是高效清洁处理陈腐垃圾的一种方法。本文通过在不同气化温度和掺混比下，探究共气化过程产物分布和合成气组分特点，分析陈腐垃圾与原生垃圾共气化协同效应。通过气化评价指标计算及响应面模拟，对掺混比及气化温度条件进行优化。结果表明，气化温度的升高促进固体残余物分解产气，提高产气率，700~1000℃气化温度下混合物的固体残余物实验值低于单一原料气化线性相加值，证明陈腐垃圾与原生垃圾共气化存在积极的协同作用促进固体焦的转化。合成气组分中H₂和CH₄高含量说明陈腐垃圾具有良好的气化特性，合成气各组分产率的实验值在900℃和1000℃条件下均大于计算值，说明较高气化温度促进合成气生成。气化评价指标中气体产率和碳转化率随陈腐垃圾掺混比和气化温度的升高增幅明显，在1000℃气化温度条件下，合成气热值和气化效率分别在陈腐垃圾掺混比为60%和80%时达到最大值。通过响应面方法模拟优化实验结果发现，陈腐垃圾在1000℃下单一气化可以得到H₂、CH₄产率最大值（188.44mL/g和104.22mL/g），但CO产率也达到最大值。陈腐垃圾掺混比在60%~89%范围内，气化温度接近1000℃，混合物共气化的合成气产物中H₂、CH₄含量较高，且可以获得较高的合成气热值、碳转化率和气化效率。本研究为陈腐垃圾与原生垃圾共气化技术研究与应用提供了基础。

关键词: 陈腐垃圾, 原生垃圾, 合成气组分, 协同效应, 模拟优化