Pyrolytic Gasification of Polyethylene Pellets in a High Temperature Fluidized Bed with a Conical Distributor

锥形分布器高温流化床中聚乙烯颗粒的热解气化

基本信息

批准号：
06650887
负责人：
AKEHATA Takashi
金额：
$ 0.64万
依托单位：
SCIENCE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

As one of the promising methods for reusing plastic waster. a pyrolytic gasification in a fluidized bed reactor has been proposed. However, there is little information on the design of conical-distributor-equipped fluidzed bed for plastic waste gasification. In this study, the pyro-lytic gasification of polyethylene (HDPE) pellets by partial combustion method was carried out in a conical distributor equipped fluidized bed, wall temperature of which was mantained mainly at 600ﾟC electrically.Using a cold fluidized bed model, silica sands behavior in the bed was investigated. The conical distributor gave a good fluidization silmilar to a spouted bed. The amount of sands flying over the densely-fluidized bed was measured and expressed by a function of air velocity.The perfoemance of gasification in the present apparatus was found to depend much on the balance between HDPE feed rate and air flow rate. The optimum air ratio to give both a product gas of high lower heat value and a tolerably small amount of oil and char, was found to be 0.2 to 0.3. The influence of the wall temperature of reactor was much less than the former two factors. The effect of silica sand amount was not so significant but the bed height/column diameter ratio of 1.2 to 1.7 was found advisable. Since the heat losses from the reactor system in all runs were found as large as about 90%, in order to suppress heat losses both operations without preheating of fluidizing gas and an operation in which all the electric heatings were cut after partial combustion started were tested. For both tests good results were obtained. For the latter, the operation could be continued for more than 2 hours after shutting off the heater and the heat loss of the run was reduced to 72%.

作为一种有前景的塑料废物再利用方法，人们提出了流化床反应器中的热解气化，但是，在这项研究中，关于配备锥形分配器的流化床的设计的信息很少。采用部分燃烧法对聚乙烯（HDPE）颗粒进行热解气化，在配有锥形分布器的流化床中进行，流化床的壁温主要保持在600℃使用冷流化床模型，研究了锥形分布器提供与喷动床相似的良好流化床中的硅砂行为。测量了流过密集流化床的砂子的量并用以下函数表示。发现本设备中的气化性能很大程度上取决于HDPE进料速率和空气流量之间的平衡，以提供具有高低热值的产物气体和空气流速。可以容忍少量的油和炭，发现反应器壁温的影响比前两个因素小得多。硅砂用量的影响不那么显着，但床高/塔直径。发现1.2至1.7的比率是可取的，因为在所有运行中来自反应器系统的热损失被发现高达约90%，为了抑制热损失，两个操作都无需预热。对流化气体和部分燃烧开始后切断所有电加热的操作进行了测试，对于后者，在关闭加热器和热量后可以继续操作2小时以上。运行损失减少至72%。