市政污泥生物干化中极端嗜热菌群作用机制与干化污泥内源蒸汽气化自催化制富氢燃气研究

This study proposes an active mechanism of biothermo-aeration drying (BT-AD) of municipal sludge using extreme-themophiles and self-catalytic hydrogen-rich gas synthesis by dried sludge gasification with internal vapor source, aiming to solve critical problems including high energy consumption during dehydration of the sludge; high consumption of organic matters in the sludge that results in disadvantages in subsequent utilization of the sludge to synthesize hydrogen gas; and formation of untargeted products during gasification of the sludge due to uneven distribution of heat under external heat source. This study employs recirculated inoculation of ancillary material under biotic ultra-high temperature to enrich the extreme-themophiles and to enhance thermotolerance of the extreme-themophiles; uses high-thoughout sequencing to characterize succession rules of the extreme-themophilic community; conducts regulation of control variables to reach biotic ultra-high temperature (≥70℃) at a fast rate to inhibit consumption of organic matters by other bacteria; conducts forced ventilation on the highly permeable sludge that granulates around ancillary materials under ultra-high temperature, to form sludge particles that are dehydrated and debonded; uses microwave as an energy source, and substances in the sludge as microwave absorbers to evenly heat up the sludge particles, and uses water in microchannels of the sludge particles as internal vapor source and gasification medium; and employs technology of fluidized bed to homogenize the sludge and expose catalysts contained in the sludge, including CaO, to the vapor sufficiently, and catalyze the reaction. This study realizes fast dehydration of the municipal sludge with no external heat source, and under low consumption of energy and organic matters, and also realizes high-quality hydrogen-rich gas synthesis using the municipal sludge.

针对市政污泥热干化能耗高，生物干化有机物消耗多，不利于后续产气，外热源污泥热解气化易造成污泥颗粒受热不均而产生非目标产物等关键科学问题，本项目提出生物自产热-通风对流干化结合微波诱导微孔道水内源蒸汽气化的研究思路。通过生物超高温系统中的辅料循环接种，富集极端嗜热菌群，增强其高温耐性；通过高通量测序，表征其群落演替规律；通过群落生态和控因调控，快速达到生物超高温条件（≥70℃），抑制非高温菌大量消耗有机物，利用超高温形成的污泥绕核颗粒的高渗透性辅以强制通风脱水，形成疏松脱粘的干化污泥颗粒。引入微波热源，利用干化污泥中的吸波组分，内源均匀加热，使污泥颗粒预留微孔道水产生蒸汽成为气化媒介；采用流化床技术均化物料，使污泥中所含氧化钙等活性催化物质充分接触气化气，催化反应向产氢方向进行。实现污泥的无外热源、低能耗、低有机物消耗的快速干化和以干化污泥为底物的高品质富氢燃气制取。

污泥，由于高度浓缩了污水中的污染物质，对环境的潜在危害较大。但污泥也由于富集大量有机物质而具有较高的生物质能源开发潜力。我国污泥产量巨大，在对其处理和资源化利用过程中，干化脱水是瓶颈，无害化是关键，能量回收是目标。本研究提出污泥生物-物理干化技术，为热解气化提供优化原料；通过对所获原料的快速热解机制研究，确定干化物料的调质效应对热解终产物影响的定性定量关系，提供快速热解的优化参数。本研究立足于污泥有机物的合理分级利用，具有国际前瞻性，将为低能耗干化破解污泥并进行清洁能源利用开辟新途径。.基于生物自产热的短期超高温结合高强度通风的两段式生物-物理过程，可实现低有机质消耗下污泥的干化-破解-调质。最佳污泥/辅料掺比（形成反应内核）为1.5:1～2:1，短期超高温条件（>65℃，3～4d）利于水分脱除并抑制微生物代谢。高温期完成颗粒化-调质后，强化通风，4d内含水率降至30%以下。两阶段生物-物理过程可有效实现污泥脱水（水分多形态转化-多途径迁移）、脱粘（难挥发有机成分长链断裂、PAM破解）及颗粒化（堆体气体渗透系数增1～3个量级、粉末化）。生物-物理干化后蛋白质、脂肪和糖类物质部分分解，半纤维素、纤维素和木质素富集，生物质颗粒热值（HHV）达9.52MJ/kg，为优良热解产氢原料。.研究生物-物理干化污泥（BDS）快速热解系统中生化组分、粒度和含水率因素影响，解析BDS微结构、调质效应同快速热解气化协同调控制富氢燃气机制。研究表明，BDS产氢主要源于成焦作用，而传统热干化污泥（TDS）则源于热挥发。500～900℃热解，BDS合成气和半焦的产量均高于TDS。大于700℃时，BDS热解合成气具有高浓度H2和CH4的特点。900℃H2含量最高，达43.7%，产率0.0181g/g污泥，显著高于国际同类研究的氢气浓度；BDS中等粒径颗粒（0.27mm<PS<4mm）提升合成气产量，有助于H2和CO生成。BDS存有适量水分可提高合成气产量、H2产率及C转化率。含水率在53.9%～62.6%区间合成气产量最大，在53.9%时H2浓度最高，达46.02%。