碱性条件下废轮胎真空热裂解研究

Vacuum pyrolysis of waste tires with basic additives

研究了废轮胎橡胶粉在450 ℃～600 ℃真空热解系统中热解的特性,以及温度和添加Na2CO3、NaOH对热解气液态产物的影响.实验表明,真空下废轮胎热解油收率在550 ℃时达到最大值,为48%左右.添加3%的NaOH能明显促进废轮胎橡胶热解,480 ℃时油产率达到最大值49.66%,随后随着温度的升高油产率呈现下降趋势.添加3%的Na2CO3对热解的促进作用不明显.热解气体产物主要有H2、CO、CH4、CO2、C2H4、C2H6以及少量其他化合物.NaOH的加入使气体产品中的H2相对体积分数明显增加,而CH4、CO、C2等的体积分数降低.通过GC和GC-MS分析热解石脑油发现,热解油品中含有11%以上的柠檬油精.

The granules of waste tire were pyrolysed under vacuum condition in the temperature range of 450 ℃ ～600 ℃, and the effects of the temperature and basic.additives of Na2CO3 and NaOH were studied. The results show that the pyrolytic oil yields reach the maximum of about 48% at 550 ℃ under vacuum condition without additive. 3% NaOH could facilitate the pyrolysis reaction markedly with the maximum oil yield of 49.66% at 480 ℃ and then decrease with increasing temperature. However, the effect is little on pyrolysis of tires when 3% Na2CO3 is added. Tire pyrolysis gas, determined by gas chromatography with TCD and FID detectors, is mainly H2, CO, CH4, CO2, C2H4 and C2H6, etc. Relative content of H2 in the pyrolysis gas increases obviously in the presence of NaOH, more than 60%, but those of CH4, CO and C2 decrease. The composition of gaseous product also varies with temperature. Pyrolytic oil fractions was distilled to recover the pyrolytic naphtha （ i. b. p ～ 205 ℃ ）. Qualitative and quantitative analysis of the pyrolytic naphtha were carried out by GC and GC-MS. It is illustrated that dl -limonene is the main component, with more than 11% concentration of the pyrolytic oil which is a chemical product with high economic value and wide industrial applications.