城市污泥与兰炭末磷酸法自黏结成型机理研究

Study on the Mechanism of Self Bonding to Municipal Sludge and Fine Semi-coke by Phosphoric Acid Method

将磷酸加入到城市污泥和兰炭末中制备型焦,测试了型焦生块和熟块的主要性能指标,并与陕西省洁净型煤标准进行对比,利用热重和红外光谱分析型焦自黏结成型的机理。结果表明,加入磷酸后,污泥和兰炭末型焦生块的热解新增一个失重阶段,在184℃出现一个最大失重速率点,对应为磷酸氢盐分解、脱水及缩聚等生成无机高分子黏结剂,进而包裹、黏结兰炭末成型。污泥中重金属含量极低,磷酸氢盐的生成量很少,型焦熟块可以成型且绝大部分指标满足陕西省洁净型煤标准,但跌落强度远不符合要求。

The formed coke was prepared from municipal sludge and fine semi-coke by adding phosphoric acid and the main performance indexes of raw block and ripe block were tested, which were compared with clean briquette standard of shaanxi province. The results showed that when phosphoric acid was added to sludge and fine semi-coke, pyrolytic reaction of block appeared a new degradation stage, which had a maximum degradation rate poin at 184 ℃ and it was corresponding to the decomposition of hydrogen phosphate, dehydration and polycondensation to form inorganic polymer binder and then wrapped, bonded fine semi-coke. Because the heavy metal content in sludge was very low, the production of hydrogen phosphate was very small. The ripe block of formed coke can be formed and most of the indexes meeted clean briquette standard of shaanxi province, but the drop strength was far from meeting the requirements.