Thermal Decomposition of Cardboard Wastes using Steam Gasification

摘要

Equilibrium calculations have been performed to determine the fate of cardboard under different steam to cardboard sample mass ratios (SCs) over a wide range of temperatures between 700 and 1173 K at atmospheric pressure. The carbon component of cardboard is modeled as solid graphite to provide insight about the behavior of steam gasification reactions. Results indicate that hydrogen (H2) gas production is highly favored with increase in temperature for SCs in the range 0.15 to 1.0 over the temperature range of 700 to 900 K. Higher temperatures, particularly at 1100 and 1173 K indicates high values of H2 and CO yield even at low SCs, indicating that the water gas reaction (C + H2O (=) CO + H2, +131 MJ/kmol) is very active. Methane (CH4) gas yield were found to be favorable at low gasification temperatures and SCs. Under low SCs and high temperature conditions the Boudouard reaction (C + CO2 (=) 2CO + 172 MJ/kmol) is favorable in the forward direction to result in high CO production. The results obtained simulate better for the well mixed and more uniform temperature distribution reactors as encountered in fluidized bed or rotary kiln reactors than that present in fixed bed reactors. The calculations provide important role of the operational conditions without building the hardware. Further data are required to demonstrate the validity of our results over a range of conditions. Such data are presently underway using our UMD laboratory scale reactor experiments under conditions similar to calculations. Detailed results are reported in the paper.