Low-NO_x Emmision Mechanism Of Distilled Spirit Lees Circulating Fluidized Bed Decoupling Combustion And The Ash Utilization

Distilled spirit lees, which is rich in cellulose, moisture as well as nitrogen, is a light industry biomass byproduct from the unique solid-state fermentation of distilled spirit in China. The discharged feature of spirit lees is concentrative and massive in luzhou region. And traditional disposal ways, used as fertilizer, feedstuff and landfilled, can’t match the treatment requirements with large scale and high speed. Based on this background, Institute of Process Engineering (IPE), Chinese Academy of Sciences (CAS) proposed and is developing a circulating fluidized bed decoupling combustion technology(CFBDC), which was demonstrated to effectively treat spirit lees with large scale, clean and low NOx emission. However, the mechanism of low-NOx emission in CFBDC is not clear. Additionally the combustion ash also needs effective utilization. Therefore, we carried out this study to solve the above two questions.In the part of low NOx emssion mechanism, experiments were carried out by using a mirco fluidized bed reaction analyzer, which developed by our research group, to investigate the effects of char, pyrolysis gas and tar produced from, spirit lees pyrolysis on the low NOx emission in the CFBDC process. The effect of simulated single compound in the tar on the NOx reduction was further studied. The results show that the tar had an obviously effect on NOx reduction, and the reduction efficiency was much higher than the pyrolysis gas and the char. At950℃, the peak values of reduction efficiency of the tar, pyrolysis gas and char were90.81%、53.11%and39.38%, respectively。Meanwhile, the pathway of nitrogen migration and transformation in the CFBDC process was also primarily understood.In the part of spirit lees combustion ash utilization, the rape culture experiments were carried out in five different kinds of soils, and the rape growth states at the germination and growth stages were measured to evaluate the effect of the combustion ash. The results show that the combustion ash of spirit lees exhibited different effects on the rape growth at different culture stages. There was an antiblastic effect on the rape growth at the germination stage in the loamy soil, but the rape growth was much improved when adding the ash to the clayey soil. The latter led the mature rape to have obviously increased net height and weight. The ash can change the pH value of the acid soil to convert the soil into neutral state and in turn to facilitate the humic acid decomposition and plant growth. Compared soils:ash=5:1(wt/wt) with original soils, the increased amplitudes of the net height of rapes in Guojiaohong Turang, Qingke Turang and Fuyang Turang were80.1%,80.9%and163.6%, respectively. As consequence, the article suggested that it was feasible and also effective to use directly the combustion ash of spirit lees as fertilizer.