In order to compare differences of bimetallic catalysts by in-situ vs. ex-situ catalysis for food waste catalytic pyrolysis, Ni/CaO monometallic catalysts and Ni-Co/CaO bimetallic catalysts were prepared by the precipitation deposition method for the catalytic pyrolysis of food waste in this paper. X-ray diffraction(XRD), Scanning electron microscopy(SEM) and Brunauer-Emmett-Teller(BET) surface area were used to characterize the catalysts.The results showed that the BET surface area was decreased after Co loading. Both catalysts could significantly promote the syngas yield as well as the content of H2 and CO. Compared with the control group(550mL/g), it was increased by 41.7% and 39.3% respectively for Ni/CaO(779.36mL/g) and Ni-Co/CaO(765.9mL/g) catalyst by ex-situ catalytic pyrolysis, while the syngas yield was increased by 15.1% and 35.6% for Ni/CaO(633.33mL/g) and Ni-Co/CaO(745.77mL/g) catalyst by in-situ catalytic pyrolysis. At the pyrolysis temperature of 800℃ by ex-situ catalytic pyrolysis, H2 content increased from 8.82%(control group) to 18.82%(Ni/CaO) and 15.6% (Ni-Co/CaO); CO content increased from 14.25%(control group) to 17.82% (Ni/CaO) and 16.08%(Ni-Co/CaO). Compared with the ex-situ catalytic pyrolysis, H2 content was increased respectively by 203.2% and CO content were decreased by 24.7% for Ni/CaO catalyst through in-situ catalytic pyrolysis; while H2 content was increased by 248.4% and CO contents were decreased by 20.2% for Ni-Co/CaO catalyst. The performance of the catalysts by ex-situ catalytic pyrolysis was superior to in-situ catalytic pyrolysis.
Zheng et al. (Sat,) studied this question.