Pyrolysis of Epoxy resin in a pilot furnace mass balance and parametric study on operating conditions

Abstract

International audienceIn order to optimize a thermal treatment for the elimination of epoxy resin from nuclear fuel samples by pyrolysis, experimental investigations are carried out with virgin epoxy resin on a pilot scale furnace and a thermogravimetric device. The main target of the treatment is an optimized reduction of the final hydrogen content in the residual solid, the so-called char. The condensable products of the pyrolysis (tar-water mixture) and the char are carefully quantified and characterized by elemental analysis, while the permanent exhaust gases are quantified by gas chromatography. In order to complete the mass balances on each element C-H-O-N and pyrolysis products, a data reconciliation procedure is applied to adjust the values of raw measurements. The reconciled mass distributions after pyrolysis at 450 DC are 78.74 wtpercent tar, 2.60 wtpercent gas, 12.84 wtpercent char and 5.82 wtpercent of water. Pilot experiments, as well as the TGA from 380 DC to 750 DC, help to quantify the significant impact of the temperature on the pyrolysis balance. Organized with a two-level fractional factorial design, 11 pilot experiments have been then conducted to achieve a parametric study on heating rate, argon gas flow rate, resin mass and plateau time for a pyrolysis temperature of 450DC. Heating rate and plateau time have been found as the two predominant factors for reducing char ratio. For residual hydrogen, the plateau time is the only significant parameter. The heating rate has been confirmed to be a factor of second order in the range of 1 to 15 DC/min with two complementary experiments