Photochemical coal dissolution. Final technical progress report, September 30, 1993--September 29, 1996

A flowing solvent photochemical reactor was designed, built and tested. A modified ACE photochemical reactor, lamp and power supply were employed. They were modified to accommodate a silica column-constrained dispersed coal sample and a solvent flowing through the silica/coal column to sweep away coal extract. Before each experiment the column was packed with the mixture of silica and coal in the annular space around the lamp. A reflective aluminum surface (foil) reflected any light-transmitted through the column for multiple passes back through the sample. A variable speed Rainin Rabbit Plus peristaltic pump was interfaced to an IBM XT computer via a Gilson RS232/RS422 converter. The purpose of the computer control was to vary the speed of the pump so as to control the absorbance of the solution of coal extract in the solvent. Absorbances at a chosen wavelength were measured by a Spec 21 spectrophotometer with a flow cell connected to the column effluent port. A signal proportional to transmittance from the Spec 21 was delivered to the computer through a Keithley DAS 801 A/D plug-in the computer. The analysis of the Spec 21 signal and control of the pump speed was based on a QuickBasic computer program written by us