甘油与丙二醇复配比例对烟草颗粒热解和释烟特性的影响

Effects of glycerin/propylene glycol ratios on pyrolysis and smoke release of tobacco granules

为考察雾化剂种类和质量分数对烟草颗粒热解和烟气释放特性的影响规律,采用湿法造粒技术,利用热重-红外光谱联用系统(TG-FTIR)、锥型量热仪(CONE)以及稳态热解装置与撞击采样器联用系统,研究甘油与丙二醇复配比例对烟草颗粒热解与烟气释放特性的影响。结果表明:(1)随丙二醇量的增加,烟草颗粒起始失重速率明显增大,总失重比例增加,主要失重温区向低温区移动,且单一雾化剂制备的烟草颗粒主要失重温区范围较小,混合雾化剂则较为宽泛;有氧裂解阶段失重速率与甘油质量分数成反比。(2)红外光谱分析结果显示,添加丙二醇后,烟草颗粒在100℃即开始释放雾化剂;随丙二醇质量分数的增加,碳水化合物、酚类、有机酸类、烟碱等胺类化合物以及烷烃、烯烃等化合物的释放量变化趋势由先增大后减小变为逐渐增大;在有氧裂解阶段,单一甘油体系裂解的气相产物以CO_(2)、H_(2)O、CO和羰基化合物为主,随丙二醇质量分数的增加,碳氢和羰基化合物的特征吸收峰增强,且CO和CO_(2)的特征吸收峰强度在350、400℃时明显增大,说明烟草裂解更为剧烈。(3)随丙二醇质量分数的增加,烟草颗粒的释烟时间范围减少,累积释烟总量降低,由30%(质量分数)丙二醇制备的烟草颗粒的起始释烟速率最小;增加甘油质量分数,烟草颗粒热解释放CO和CO_(2)的速率减小。(4)随甘油质量分数的增加,气溶胶总质量呈增加趋势,平均粒径则呈先减小后增大的趋势。

To study the influences of types and contents of aerosol carriers on pyrolysis and smoke release of tobacco granules,wet granulation of tobacco was prepared with different glycerin/propylene glycol ratios.The granule samples were studied with thermogravimetric-Fourier transform infrared(TG-FTIR),cone calorimeter(CONE),and steady-state pyrolysis.The aerosol particle size formed was analyzed using an impact particle analyzer.The results showed that:1)With the increase of propylene glycol,the initial weight loss rate and total weight loss of tobacco granules increased significantly.The main weight loss temperature region shifted towards lower temperature regions.The main thermal weight loss temperature range prepared with single aerosol carrier was narrower than that with the mixed aerosol carrier.Moreover,the weight loss rates at the oxidative pyrolysis stage were inversely proportional to the glycerin content.2)The infrared spectra indicated that tobacco granules began releasing aerosol carrier from 100℃when propylene glycol was added.With the increase of propylene glycol content,the releases of carbohydrates,phenols,organic acids,amines(eg.nicotine),alkanes,olefins and other compounds changed in a complex manner.At the oxidative pyrolysis stage,the main gaseous products from tobacco granules containing glycerin were CO_(2),H_(2)O,CO and carbonyl compounds.With the increase of propylene glycol content,the characteristic peaks of hydrocarbons and carbonyl compounds were strengthened,and the intensities of characteristic CO and CO_(2)peaks increased at 350 and 400℃respectively,suggesting a more severe pyrolysis of tobacco.3)With the increase of propylene glycol,the range of smoke release time decreased,the total amount of smoke release reduced.The tobacco granules prepared with 30%(mass fraction)propylene glycol had the slowest initial smoke release rate.With the increase of glycerin content,the release rates of CO and CO_(2)from tobacco granule decreased.4)With the increase of glycerin content,the total mass of aerosol increased,while the mean particle size of aerosol decreased first and then increased.