# The relationship between the pore characteristics of semi coke and its adsorption performance

Pubdate: 12-05 2021

The pore structure of semi coke l is an important indicator of the adsorption performance of semi coke l. Someone has used nitrogen isotherm adsorption method to study the influencing factors of the pore structure of semi coke l. The purpose of the research is to influence the pore structure of semi coke l by atmospheric pressure and pressurized gasification. influences. The results of the research on several samples show that the specific surface area, pore specific surface area and specific pore volume of semi coke l are significantly increased compared with raw coal.
The production purposes of coal gasification and coking are different. The former aims to produce as much gas as possible under certain energy consumption conditions, while the latter aims to produce semi coke l that meets the requirements of product quality standards by controlling the process parameters of the coking process. . High-quality semi coke l requires less ash and moisture, and volatile content should not be too high (air drying base volatile content should generally be less than 4%).
Through the element analysis and pore structure analysis of several typical industrial blue carbons, the following conclusions are obtained:
(1) semi coke l is a by-product of coal pyrolysis at a lower temperature, with a volatile content of 2.47%~5.23%
(2) The pore volume of semi coke l is 0.05~0.15cm3/g, the specific surface area is 6.6~14m2/g, and the porosity is 12%~23%, indicating that the pore structure of industrial semi coke l is underdeveloped, such as direct use as an adsorbent , Its adsorption capacity is very limited, therefore, it is necessary to further activate, increase the pore volume and specific surface area.
(3) In the range of pore radius of 50~1000nm, the pore volume of most blue carbon samples accounted for a larger share of the total pore volume of the sample; however, the pore radius range where the specific surface contributes to the total specific surface area of the sample is less than 20nm . It shows that there are many pores with a pore radius of less than 20nm in the sample, which accounts for a large proportion of the total pores, which is conducive to gas adsorption.
(4) The pore structure parameters of different blue carbon samples are quite different. Among them, SMJH pore capacity and HSMQ are the smallest, with a difference of 0.10m3/g; DTMQ has the largest specific surface area and HSMQ is the smallest, with a difference of 7.4cm2/g; SMJH pores The rate is the largest, HSMQ is the smallest, the difference between the two is 11%. The difference between the samples is also manifested in the difference in pore size distribution. The reasons for these differences are the raw material coal types and the process conditions of semi coke l production.
Studies have pointed out that industrial semi coke l is a porous material with a complex microscopic pore topology. Based on fractal theory, the fractal dimension is introduced to quantitatively characterize and describe the roughness and complexity of the irregular pore structure of industrial blue carbon. Select industrial semi coke l samples with typical coal types and representative processes, measure their pore structure characteristics with a porosity analyzer, and use the measured data to analyze and calculate the fractal dimension.
The calculation results show that the pore structure of industrial blue carbon conforms to the fractal characteristics. Under the measurement conditions of the sample particle size of 2.36~3.35mm, the fractal dimension of the sample is between 2.7982~2.9154, and its coefficient of determination is between 0.9157~0.9614. ; The fractal dimension of the sample has a certain relationship with coal type and semi coke l pyrolysis process. Through the calculation and analysis of the fractal dimension of industrial semi coke l, it is possible to understand its pore structure characteristics more comprehensively and accurately, in order to provide a more reliable basis for the analysis and evaluation of its adsorption and activation potential and the formulation of appropriate activation processes.