A sequential process for hydrogen production based on continuous HDPE fast pyrolysis and in-line steam reforming

Abstract

A continuous process has been developed consisting in the flash pyrolysis (500 ºC) of high density polyethylene (HDPE) in a conical spouted bed reactor (CSBR) followed by steam reforming in a fluidized bed reactor (Ni commercial catalyst). The effect reforming temperature in the 600-700 ºC range, space time from 2.8 to 20.8 gcat min gHDPE-1 and steam/plastic ratio between 3 and 5 have on product yields and gas composition has been studied. The continuous pyrolysis-reforming process performs well, with no operational problems and attaining complete HDPE conversion. Under the optimum conditions, i.e., 700 ºC, space time 16.7 gcat min gHDPE-1 and steam/plastic of ratio 5, the H2 yield was 92.5 % of that corresponding to stoichometry, which accounts for a H2 production of 38.1 g per 100g of HDPE in the feed.