Developing Suppression Techniques for Dioxin (DXN)s Released from Small-scale Incinerators for Industrial Wastes by Adding Titania Particles

开发添加二氧化钛颗粒抑制小型工业废物焚烧炉释放的二恶英 (DXN) 技术

基本信息

批准号：
13555218
负责人：
EMI Hitoshi
金额：
$ 8.38万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

The present work is aimed at developing a method for suppressing the formation of dioxin (DXN)s emitted from small-scale incinerators for industrial wastes, which are difficult of operate under well controlled combustion, by adding a chemical (sulfur-contained titania) into incinerators. In the first year, the lab-scale experiments on incomplete combustion of me waste samples prepared by adding hydrated lime (Ca(OH)_2) with a given content into PVC powders were performed. The experiments revealed that the DXNs concentration in the burnt samples with 33.2wt%-added Ca(OH)_2 decreased by about 1/10 compared to that without the addition. However, we concluded that this technique adding chemicals into an incinerator is insufficient for the future regulation of tolal emission even if titania, which might be more reactive than Ca(OH)_2 is applied. Thus, we focused on the secondary heat treatment for fly ash in which DXNs arc most concentrated. In the conventional method, DXNs in the fly ash a … More re dechlorinated under reductive atmospheres below 500 deg. C. by adding some chemical since fly ash is subject to solidification above 500 deg. C. In the second year, we investigated the mechanism on solidification of fly ash at the high temperature and attempted to establish the technique of high-temperature treatment for fly ash preventing it from the solidification. Sodium hydroxide (NaOH) and mullile were chosen as an additive that can trap chlorine in fly ash, assuming that it might contribute the solidification, and then me chosen chemical was mixed with fly ash at a given ratio, followed by heating in an electric furnace at 700 deg.C. It was found that no solidification of fly ash with the additives took place after the heat treatment. Moreover, the X-ray diffractometer analyses indicated that the fly ash prior to the heating did not contain calcium chloride (CaCl_2) but CaClOH, which was a product of reaction between Ca(OH)_2 and HC1, and that sodium chloride (NaCl) was detected in the heated sample with NaOH and wadalite in the treated one with mullitc. The differential thermal analyses revealed that for the sample without additives there was an exothermic peak in ihe cooling step (around 800 deg.C). while this peak was not detected in that with additives. Furthermore, the DXNs in the samples before and after the heal treatment were analyzed. The results showed that DXNs concentration in the treated samples with additives decreased by less than 1/!05 compared to the untreated one without additives. These findings confirmed that the application of these additives has the advantages not only to prevent fly ash from the solidification but also to enhance the decomposition of DXNs. Less

目前的工作旨在开发一种从小规模焚化炉中抑制二恶英（DXN）的方法，用于工业废物，通过将化学物质（硫磺含有硫磺的钛）添加到焚化炉中。在第一年，通过将水合石灰（Ca（OH）_2）添加给PVC粉末中的水合石灰（Ca（OH）_2）制备的ME废物样品不完全组合进行实验室规模实验。实验表明，与没有添加的情况相比，燃烧样品中的DXNS浓度减少了约1/10。但是，我们得出的结论是，该技术将化学物质添加到焚化炉中不足以对未来的总排放调节，即使二氧化钛可能比应用CA（OH）_2更具反应性。这，我们专注于粉煤灰的二级热处理，其中DXNS弧度最集中。在常规方法中，粉煤灰中的DXN在低于500度以下的大气下进行了重新氯化。 C.通过添加一些化学物质，因为粉煤灰受到500度以上的凝固。 C.在第二年，我们研究了高温下粉煤灰固化的机制，并试图建立高温处理技术，以防止其凝固。选择氢氧化钠（NaOH）和mullile作为一种添加剂，假设它可能有助于固化，然后以给定比率将粉煤灰与粉煤灰混合，然后在700摄氏度的电炉中加热。发现在热处理后，没有对添加剂的粉煤灰进行凝固。此外，X射线衍射仪的分析表明，加热之前的粉煤灰不含氯化钙（CACL_2），但是Cacloh是Ca（OH）_2和HC1之间的反应的产物，该反应是氯化钠（NACL）在NaOH和NaOH中检测到的NaOH和WADALITE和WADALITE的热样品中的Mull naH和WADEC。差分热分析表明，对于没有添加剂的样品，冷却步骤中有一个放热峰（约800摄氏度）。虽然添加剂未检测到该峰。此外，分析了健康处理前后的样品中的DXN。结果表明，与未经处理的未经处理的添加剂相比，处理过的样品中的DXNS浓度降低了1/！05。这些发现证实，这些添加剂的应用不仅具有防止凝固凝固的优势，而且还可以增强DXN的分解。较少的