Experimental investigation of the effect of microwave drying and reactor temperature on product yields from pyrolysis of cassava chaff

Effect of microwave oven drying and reactor temperature has been investigated in this study. Cassava chaff was procured fresh from a cassava flour processing industry in Ogbomoso, Oyo State, South-Western Nigeria. The sample was water washed to remove excess alkali metal present through hydrolysis, sun dried and ground to obtain a uniform size distribution of 2-4 mm. Samples of 50 g each were microwave dried at five different temperatures (60, 75, 90, 105 and 120 ) at a constant time of 30 minutes. The samples were then pyrolyzed in a fixed bed reactor at different temperatures (400, 500, 600 and 700 ) at atmospheric pressure using a residence time of 20 minutes. Results showed that tar yield decreased as both reactor and drying temperatures increased. The yield of char increased as drying temperature increased and decreased as reactor temperature increased except at 700 where possibly repolymerization of light molecular species occurred. The yield of pyrogas was found to increase as both reactor and drying temperatures increased. It was established that both drying and reactor conditions influence products yields distribution during biomass pyrolysis.  http://dx.doi.org/10.4314/njt.v35i4.2

A Mathematical Model for the Prediction of Injectivity Decline

Injectivity impairment due to invasion of solid suspensions has been studied by several investigators and some modelling approaches have also been reported. Worthy of note is the development of analytical models for internal and external filtration coupled with transition time concept for predicting the overall decline in injectivity. This study presents a new mathematical model which is based on mass balance of particles flowing through the porous media by coupling rate changes in injection pressure within the reservoir due to formation damage with rate changes in porosity within the invaded region. This model when fully validated will ensure the reliability of injectivity decline prediction from a well injectivity index history which will further pave way for an effective planning of water treatment whereby creating a new frontier in the management of produced water in oil and gas technology.Keywords: Injectivity impairment; internal filtration; External filtration; water injection; filter cake; porosity reduction; formation damage; injection declin