A laboratory reactor was designed to test the effect of the interference instant of HY on the pyrolysis of pubescens.The time instant for intermediate species from pyrolysis to contact HY was controlled by varying the position of the catalyst bed relative to the pyrolytic cell.It was found that the effect of the interference instant was significant on the variation of different intermediate species

and the yield and quality of the products.The results also showed that

with the increase in the distance between the pyrolytic cell and the catalyst bed

the yield of liquid and relative content of the organics such as aldehyde

phenols

etc.

decreased

while the yield of residue and relative content of acetic acid increased.The deoxygenation of the intermediate species was favored when the catalyst exerted its performance on them immediately after their formation.