19-08-2014, 10:25 AM
Microwaves can be successfully employed for air blowing of the heavy residues, leading to the formation of higher molecular weight compounds like asphaltenes from maltenes. Kinetic studies based on the change in content of various constituents of AMVR revealed that the conversion of oils to asphaltenes followed by a, irreversible, first order series mechanism, with the formation of resins as an intermediate step.Changes in content of constituents and rate constants are found to be higher in experiments carried out with and without microwaves as cited in literature. Increase in air flow rate did not mark any influence on the changes in contents of various constituents of AMVR, and effect of temperature on rate constants were correlated by Arrhenius equation. The rate equations were characterized by low-frequency factors, thus indicating the occurrence of a chain mechanism involving free radicals.
Microwaves can be successfully employed for air blowing of the heavy residues, leading to the formation of higher molecular weight compounds like asphaltenes from maltenes. Kinetic studies based on the change in content of various constituents of AMVR revealed that the conversion of oils to asphaltenes followed by a, irreversible, first order series mechanism, with the formation of resins as an intermediate step.Changes in content of constituents and rate constants are found to be higher in experiments carried out with and without microwaves as cited in literature. Increase in air flow rate did not mark any influence on the changes in contents of various constituents of AMVR, and effect of temperature on rate constants were correlated by Arrhenius equation. The rate equations were characterized by low-frequency factors, thus indicating the occurrence of a chain mechanism involving free radicals.
In comparison to the noncatalytic reactions, the use of Ceric Sulphate as a catalyst reduced blowing time, for same changes in content of constituents. Catalyst loading of 1 – 1.5% (w/w) was found to be adequate. Air blowing reactions of heavy residue with microwaves were modeled to obtain temperature profile in course of reaction, if values of all parameters are known. Energy balance calculations showed hat energy efficiency with respect to energy supplied and energy absorbed was low. Optimization of microwave reactor design is required in order to increase the ratio of energy absorbed by reaction mixture to energy supplied by magnetron.