不同酿酒原料的白酒糟燃烧中NO_(x)和CO的排放特性

Emission characteristics of NO_(x)and CO during the combustion of distiller's grains derived from different liquor-making materials

白酒糟是酿酒过程中玉米、小麦和高粱等发酵后产生的残渣,在经过干燥后具有较高的热值,对其燃烧利用能够实现废弃酒糟处置的无害化、减量化和资源化。然而,不同酿酒原料的白酒糟在成分上存在差异,且含氮量一般较高,其燃烧产生的NO_(x)属于酸性污染气体;酒糟的水分和挥发分也较高,燃烧过程中易产生CO等不完全燃烧产物。针对不同酿酒原料的白酒糟在燃烧过程中NO_(x)和CO排放存在差异和排放规律不明确的问题,借助一维管式炉研究了玉米酒糟(CDGS)、小麦酒糟(WDGS)和高粱酒糟(SDGS)在不同温度和含水率下燃烧时的NO_(x)和CO排放特性。研究结果表明,随着温度升高,3种白酒糟的燃烧反应加快,NO_(x)排放浓度峰值出现的时间提前,NO_(x)的排放浓度峰值和平均排放浓度增大;NO_(x)排放量和氮转化率随温度升高呈现先升高后降低的趋势,且在700℃时达到最大值,SDGS,WDGS和CDGS的NO_(x)排放量分别达到1.32,1.64和1.89 mg,氮转化率分别达到12.4%,15.6%和21.1%;随着温度升高,CO的峰值排放浓度和平均排放浓度均呈现先增加而后减少的趋势,且在600℃时达到最大;SDGS和CDGS的CO排放量在600℃时达到最大值,分别为20.27和19.80 mg,而WDGS的CO排放量在500℃时达到最大值,为20.20 mg。酒糟在700℃燃烧时,随着含水率增加,燃烧反应推迟,NO_(x)排放浓度峰值和平均排放浓度均有不同程度的增加,氮转化率则无明显变化;而CO排放浓度峰值、平均排放浓度和排放量均增加。

Distiller's grains are the residues produced after the fermentation of corn,wheat,or sorghum,in the brewing process of different kinds of liquors.They have higher heat values after drying and thus can be burned to achieve harmless disposal,minimization,and resource utilization.However,there are differences in the composition between different distiller's grains,and the nitrogen contents are generally high,so NO_(x)would be produced during their combustion.They also have high moisture and volatile matter,so incomplete combustion products such as CO are easy to generate.To reveal the differences in NO_(x)and CO emissions during the combustion among distiller's grains derived from different liquor-making materials,and to solve the problems of unclear emission laws,a one-dimensional tube furnace was used to investigate the NO_(x)and CO emissions during the combustion of distiller's grains derived from corn,wheat,or sorghum at different temperatures and moisture contents.The results showed that with the increase of temperature,the combustion reactions were accelerated,the peaks of NO_(x)emissions appeared earlier,the peak values and average values of NO_(x)emission concentrations both increased,NO_(x)emission masses and nitrogen conversion rates showed a trend of increasing first and then decreasing,and reached the maximum value at 700℃.NO_(x)emission masses of sorghum-based distiller's grains(SDGS),wheatbased distiller's grains(WDGS),and corn-based distiller's grains(CDGS)reached 1.32,1.64,and 1.89 mg,respectively,and nitrogen conversion rates of these three kinds of distillers grains reached 12.4%,15.6%,and 21.1%,respectively.For three kinds of distiller's grains,with the increase in temperature,the peak values and average values of CO emission concentrations both increased first and then decreased,they reached the maximum values at 600℃.CO emission masses of SDGS and CDGS reached the maximum at 600℃,at 20.27 and 19.80 mg,respectively,but for WDGS,the maximum value of 20.20 mg appeared at 500℃.At 700℃,with increasing moisture content,combustion reactions were delayed,peak values and average values of NO_(x)or CO emission concentrations both increased,and CO emission masses also increased.