炉前煤低温干馏工艺中的挥发分除尘

Hot dust removal in the process of low temperature coal pyrolysis

为了寻求优化的炉前煤低温干馏工艺中的挥发分除尘方案,在使用400目金属滤网对间歇式粉煤固体热载体热解装置挥发分除尘研究的基础上,将颗粒床过滤器用于该过程的除尘研究。热态除尘实验表明,颗粒床的使用有效地降低了滤网的过滤负荷。选用2 mm石英砂和φ5 mm×2 mm瓷环作为滤料,通过对比实验发现,两种滤料除尘效率均在90%以上;随着过滤操作的进行,由于颗粒床内粉尘的沉积使其过滤效率有所提高,而对气、液收率的影响很小。结果表明,颗粒床与滤网结合可作为粉煤炉前低温干馏工艺中可供选择的挥发分除尘方案。

In the process of low temperature coal pyrolysis, fine particles carried over by pyrolysis gas have negative effect on the tar capture and quality, which is one of the key points for the process development. Filter screen and granular bed were studied for dust capture in the intermittent experiment of pulverized coal pyrolysis with solid heat carrier. Distribution of fine particle size indicates that the fine dust particle especially less than 100 μm takes more than 80% of the dust. Filter screen shows a high efficiency of more than 99.9% in the dust removal tests. The result of granular bed filter combined with filter screen in this process indicates that the granular bed filter reduces the charge of filter screen. The dust removal efficiencies of the two chosen granular bed material, quartz sand and ceramic ring, are more than 90%. Dust removal efficiency increases from 91.3% to 97.3% in three intermittent tests using ceramic ring as the granular bed material. Dust deposition has no influence on the yield of gas, and has a litte influence on the yield of tar because some tar fractions are absorbed by deposited dust. It can be concluded that the combination of a moving granular bed filter with a filter screen can be used in the hot process of co-generation system for dust collection.