Coal Pyrolysis for High-Quality Tar and Gas in 100 kg Fixed Bed Enhanced with Internals

Using internals in kilogram-laboratory fixed bed pyrolysis of coal has been newly reported to greatly upgrade the pyrolysis performance in terms of the yield and quality of the produced tar and pyrolysis gas. This work is devoted to further verifying such a finding through pyrolysis tests in enlarged fixed bed reactors with and without internals at obviously increased coal treatment capacities of about 100 kg of coal per test. The reactors were electrically heated, and the tests were via batchwise operation, while Yilan sub-bituminous coal was used. Comparing the results from reactors without and with the particularly designed internals demonstrated that the use of internals increased the heating to the coal bed by about 20%, while the tar yield was 87.0% of the Gray-King (G-K) tar yield, which was obviously higher than 46.9% of the G-K tar yield from the reactor without internals. In the tar from the internal-enhanced reactor, the content of light tar (boiling point below 360 degrees C) was about 71 wt %. Raising the furnace temperature from 900 to 1100 degrees C increased the tar yield from 80.5% to 90.3% of the Gray-King tar yield for the reactor with internals. Parametric studies were performed for coal particle size, heating furnace temperature, and coal moisture content.