Hi, I am Ranjeet Mishra from India. I want to know what exactly happens during formation of secondary cracking reaction during pyrolysis of biomass. is it possible by this reaction formation of phenol will be more?
Though it is a component-wise pyrolysis paper but it could help you to analyse that what kind of products may appear in different stages. The feedstock is vanillin. In tertiary stage, general appearance of products are the non-oxy 5-6 carbon membered rings, phenol, polymerizing components which help in coking, etc.
Secondary cracking, at large, is quite a complex process, highly dependent on temperature, pressure, gas phase composition, and the presence of potentially catalytic surfaces, such as the reactor wall and coke. Another important variable is time.
Temperature acts on the rate of all reactions, and also on all kind of reaction equilibriums.
Pressure stimulates reactions of condensation, vacuum and very low pressure act to the opposite.
My experience is mainly in a range of 600-900 °C and I found it feasible to monitor primary as well as secondary reactions in cases such as propane and butane pyrolysis.
Obviously, biomass pyrolysis is generally at much lower temperature. Products are more complex and diverse. Moreover, phenol and its derivatives are quite reactive, so - even if they form rapidly, their depletion could be even faster.
There is a large body of knowledge gathered on chlorophenols: in minutes these will dimerise to PCDD/F when a suitable contact is available.
I am afraid that there are barely good answers to your question, since its scope is quite vast and undefined.