Objective Preparing graphitized foam materials using heavy tar produced by the pyrolysis of tar-rich coals plays a significant role in the high-value utilization of tar-rich coal resources.
Methods This study aims to prepare high-performance carbon foam materials by investigating the relationships between various reaction conditions and carbon foam performance. First, using mesophase asphalt prepared with heavy tar as the precursor, carbon foams were developed via the high-temperature self-foaming method. Then, the effects of different reaction temperatures, heating rates, and reaction pressures on the performance of coal tar-based carbon foams were examined. Finally, quadratic multinomial regression equations were established using Box-Behnken response surface experiments, revealing the relationships of the porosity and thermal conductivity of the carbon foams with various reaction conditions.
Results and Conclusions The experimental results indicate that the reaction temperature, heating rate, and reaction pressure significantly influence the performance of coal tar-based carbon foams. The optimal porosity of the carbon foams was 72.8%, corresponding to a temperature of 559 ℃, a pressure of 0.48 MPa, and a heating rate of 9 ℃/min. In this case, the effects of these reaction conditions decreased in the order of temperature, pressure, and heating rate. The optimal thermal conductivity value of the carbon foams was 0.219 W/(m·K), corresponding to a temperature of 549 ℃, a pressure of 2 MPa, and a heating rate of 3.9 ℃/min. In such an instance, the effects of these factors decreased in the order of heating rate, pressure, and temperature. The process parameters optimized using the response surface model enable the preparation of carbon foam materials with high porosity and thermal conductivity, providing a new solution for enhancing the pyrolysis efficiency of tar-rich coals.
DownLoad: