双碳目标背景下,我国积极推进高湿污泥/生物质资源化技术的发展和应用。化学链技术作为一种新兴的能源利用方法,在处理有机固废方面得到了广泛应用研究。概述了高湿污泥与农林废弃物常用处置技术及化学链气化技术研究现状,着重归纳了化学链气化过程中灰分与水分对气化特性影响的研究进展。载氧体作为化学链技术中关键的一环,其应用研究已取得丰硕成果,在众多载氧体中,铁基载氧体因其低成本与较高的载氧能力成为化学链气化最受关注的载氧体,但其反应活性较低,需掺杂Ni、Ca、K等元素进行改性。污泥和生物质的灰分及水分对于气化产物和气化效率有双向影响,甚至影响NOx排放。污泥/生物质灰分中含有的K、Ca等氧化物有助于提高载氧体活性,但反应速率太高会造成载氧体局部烧结,继而降低载氧体活性;循环的灰分与气相充分接触,对气体重整具有一定催化作用,从而提高了合成气品质。尽管污泥/生物质中水分析出吸收大量热量,但部分水蒸气和载氧体协同促进碳气化反应从而提高了H2生成率,提高富氢燃气品质;水蒸气作为气化剂过量供给时,CO2产量明显增加,降低了合成气品质。因此,污泥和生物质在化学链气化过程中须利用灰分和水分的正向影响以提高气化效率,控制循环灰量和水分析出速率是关键途径。

The development and application of high-wet sludge/ biomass resource technology are recently promoted in China under thebackdrop of the dual carbon target. Chemical looping technology, as an emerging method for energy utilization, has been widely applied inthe treatment of organic solid waste. The research status of the commonly used disposal technologies of high-wet sludge and agroforestrywaste and chemical looping gasification were summarized. The research progress on the influence of ash and moisture on gasification characteristics during chemical looping gasification process was emphasized and summarized. The oxygen carrier, as a crucial component inchemical looping technology, has been achieved abundant research results. Iron-based oxygen carrier is one of the most concerned oxygencarriers among various oxygen carriers in chemical looping gasification because of their low cost and high oxygen-carrying capacity. However, its reaction activity is relatively low, which needs to be modified by doping Ni, Ca, K and other elements. The ash and moisture inthe sludge have bidirectional effects on the gasification products and gasification efficiency, and even affect the NOx emission. The oxygencarrier activity can be improveddue to the K and Ca oxides contained in sludge/ biomass ash, but the increase of reaction rate will lead tolocal sintering of oxygen carrier, thereby reducing the oxygen carrier activity. The circulating ash is in full contact with the gas phase,which has a certain catalytic effect on gas reforming, thus improving the quality of syngas. Although the release of moisture from sludge/ biomass absorbs a large amount of heat into vapor, a moderate amount of water vapor and oxygen carrier co-participate in the reaction of carbon conversion into syngas of rich H2, which promotes the quality of hydrogen-rich gas. When water vapor is excessively supplied as agasification agent, CO2 production increases greatly and the syngas quality is reduced. Therefore, the positive effects of ash and moistureshould be used to improve the gasification efficiency of high wet sludge and biomass in the process of chemical looping gasification, inwhich the control of circulating ash amount and moisture release rate is the key way.

0 引言

1 市政污泥与生物质处置现状

   1.1 市政污泥处置现状

   1.2 生物质处置现状

2 污泥与生物质化学链气化研究现状

   2.1 化学链气化技术

   2.2 污泥化学链气化

   2.3 生物质化学链气化

   2.4 污泥与生物质共化学链气化

3 灰分对化学链气化特性的影响

4 水分对化学链气化特性的影响

5 结语及展望