Oil Shale, Vol.37, No.2, 89-103, 2020
Analysis of the pore structure of Longkou oil shale semicoke during fluidized bed combustion
The combustion experiment of Longkou oil shale semicoke was conducted in a batch fluidized bed reactor. A specific surface area (SSA) analyzer and a scanning electron microscope (SEM) were used to respectively measure the specific surface area of samples and examine their surface pore structure in different experimental operating conditions, and the fractal dimension (FD) was used to describe the complexity of pore morphology. The results showed that Longkou oil shale semicoke had a developed pore structure, and in the combustion process, its SSA and pore volume first increased and then decreased, remaining finally unchanging. Most pores were micropores and mesopores of about 2 nm in size. The pore structure was fully developed at a temperature of 600 degrees C, at which the specific surface area and pore volume also reached maximum values. There were great differences in the pore size distribution of semicoke with different particle sizes. As calculated by the box-counting method (BCM) and the Frenkel-Halsey-Hill (FHH) equation, the pore size showed similar trends of variation, increasing first and then decreasing slowly.