Hydrogen Production from Steam Reforming of m-Cresol, a Model Compound Derived from Bio-oil: Green Process Evaluation Based on Liquid Condensate Recycling

Liquid pollutants and coke formation can cause many problems in steam reforming of bio-oil for hydrogen production. From an environmental and economic point of view, an operation of liquid condensate recycling aiming at eliminating secondary pollution as well as carbon deposition was applied in this work. Under the optimal reaction conditions, m-cresol (a heavy organic compound present in bio-oil) was steam-reformed on a highly efficient commercial Ni-based catalyst for 6 h time-on-stream. Gas product distribution, liquid pollutant formation, and carbon deposition behavior were investigated, respectively. On the basis of one-time liquid condensate recycling, a green and efficient steam-reforming process can be achieved. Under different reaction conditions, the possibility of achieving this green process was evaluated. The results indicated that under a much higher temperature (900 degrees C), m-cresol becomes easier to steam reform but it is still impossible to achieve a green process just by a single steam reforming. Under a low temperature (800 degrees C), low steam/carbon ratio (2.5), or high weight hourly space velocity of bio-oil (1.0 h(-1)), it is difficult to eliminate the liquid pollutants completely by one-time liquid condensate recycling. However, for every single test, the operation of liquid condensate recycling can make a contribution to the increase of the hydrogen yield and the reduction of secondary pollution and coke formation. It provides an alternative route for steam reforming of bio-oil, especially for some heavy components in bio-oil.