Analysis of Char Specific Surface Area and Porosity from the Fast Pyrolysis of Biomass and Pulverized Coal

Abstract

In this paper, the chars of wood dust, corn straw, rice husk and coal pulverized were obtained at different residual time of various pyrolysis temperature (1173 K, 1273 K and 1373 K) during the process of flash pyrolysis in the drop tube furnace (DTF). In order to obtain the parameters of porous structure which included specific surface area, pore volume and fractal dimension of char, low-temperature nitrogen adsorption method was employed to obtain nitrogen adsorption isotherm of chars sample. For the four chars, the corn straw char had the biggest specific surface area and pore volume, the rice husk in second place, the wood dust in third place, and the pulverized coal char in the last one. By taking Frenkel-Halsey Hil (FHH) method to analyze the fractal character of char surface structure, we found that the fractal dimension of biomass except wood char is higher than those of pulverized coal char.

Thermochemical Conversion of Biomass Char under Carbon Dioxide Flux in a Thermally Supported Environment: Experimental and One-Dimensional Numerical Investigations

“…The severe deviations in the conversion behavior and magnitude time scales between coal char and biomass char gasification is due to their distinct structural and morphological characteristics. Inferring from the investigation of Luan et al, under similar pyrolysis conditions (0.5 mm particle, 900 °C, 1.2 s residence time), the surface area and pore volume of coal char was 18.3 m 2 g –1 and 0.04 mL g –1 , whereas for biomass char a surface area of 90.5 m 2 g –1 and pore volume of 0.12 mL g –1 was noted. Similar observations are also made by Wang et al, and in addition, scanning electron microscopy (SEM) images indicated a near-uniform pore structure of wood char as compared to coal char wherein more convolution is noted.…”

Impact of CO2 on Pyrolysis Products of Bituminous Coal and Platanus Sawdust

“…The parameters of pore structure of the chars under the atmospheres of N 2 and CO 2 are presented in Table 2. The release of gas from the reaction of char gasification during pyrolysis can open the old holes and produce new holes, which will lead to the expansion of closed pores of char [33] and contribute to the change in pore size distribution and specific surface area.…”