Research on Hydrogen Production from Waste Plastics Using the High Temperature Steam Reforming Process

利用间歇式裂解/水蒸气重整装置研究了三种纯塑料材料(PE、PP和PS)的裂解和水蒸气转化性能。研究了重整温度、重整停留时间和蒸汽比[供蒸汽摩尔/裂解气碳摩尔/秒]3个操作参数对水蒸气重整反应的影响。结果表明，每种塑料的转化温度越高，气体转化率和氢气产率都越高。在600℃的温度下，所有塑料原料都可以完全气化，比非催化重整所需的温度低400℃左右。将重整温度设为600℃，水汽比设为1，考察了重整炉内停留时间对水蒸气重整反应的影响。根据塑料材料的不同，完全气化和产生足够的氢气需要停留时间。将重整温度设为600℃，停留时间设为0.9s，考察了水蒸气比对水蒸气重整反应的影响。结果表明，每种塑料原料都能成功地产生50-65%的富氢燃气，该工艺是生产富氢燃气的有效方法。最后，对由于对苯二甲酸在热解气体冷却过程中发生冷凝而难以热解的聚酯材料进行了类似的实验。结果表明，水蒸气重整完全抑制了凝析油的生成，即使在聚酯原料的情况下也能产生富氢燃料气。

Pyrolysis and steam reforming performances of three pure plastic material (PE, PP and PS) were investigated using a batch-type pyrolysis/steam reforming equipment. The effects of three operating parameters (the reforming temperature, the residence time in the reformer and the steam ratio [mole/sec of steam supplied / mole/sec of carbon in the pyrolysis gas] ) on the steam reforming performance were clarified.At first, the effect of the reforming temperature on the steam reforming reaction was investigated by setting the residence time at 1.5 sec. and the steam ratio at 1. As a result, the gas conversion rate and the hydrogen yield both increased by increasing the reforming temperature for each plastic material. All the plastic material could be completely gasified at the temperature of 600℃, which is about 400℃ lower than that required for the non-catalytic reforming. Next, the effect of the residence time in the reformer on the steam reforming reaction was investigated by setting the reforming temperature at 600℃ and the steam ratio at 1. The results showed that 1-1.5 sec. residence time is required for complete gasification and sufficient hydrogen production depending on the plastic material. Then the effect of the steam ratio on the steam reforming reaction was investigated by setting the reforming temperature at 600℃ and the residence time in the reformer at 0.9 sec. As a result, it was demonstrated that hydrogen rich (50-65%) fuel gases were successfully generated for each plastic material, and that this process is effective for production of hydrogen rich fuel gases.Finally, the similar experiments were done for PET material which is hard to be pyrolyzed due to condensing of terephthalic acid in the course of cooling of the pyrolysis gas. The results showed that the steam reforming completely suppresses formation of condensates and hydrogen rich fuel gas can be produced even in the case of PET material.