1 INTRODUCTION
SOx and NOx are the most important sources of atmospheric pollution in China. With the continuous implementation of environmental protection, SO2 and NOx emissions have continued to decrease. In recent years, the “ultra-low emissions” that have been bred and implemented have put forward stricter standards for pollutant emissions from energy-intensive industries such as coal-fired power plants. As a flue gas desulfurization, denitration process that is expected to achieve “ultra-low emission”, the activated coke (AC) flue gas treatment process is widely used in China[1-5].
At present, AC flue gas purification mainly is a moving bed integral reactor[6-10]. In the adsorption tower and desorption tower, the AC move downward by its own gravity to complete the denitration-desulfurization-regeneration cycle. During this process, the large pressure pressing on AC in the lower part of the adsorption and desorption tower may cause partial AC to crush. The friction between the AC particles or the AC and the equipment may cause the AC to wear. In addition to a small amount of chemical consumption during thermal regeneration, the consumption of AC is mainly due to physical damage[11]. Therefore, the AC mechanical strength indicator, such as the compressive strength and abrasion resistance, directly determine the service life of the AC[12].
A lot of research about the influencing factors of AC desulfurization and denitrification performance has been done, but there are only a few study on the influencing factors of AC mechanical strength, so it is difficult to purposefully product the high strength AC. It is generally believed that the developed pore structure leads to the looseness of the AC skeleton, which deteriorates the AC mechanical strength, but the specific pore structure characteristic index that affects the mechanical strength of the AC are not clear. In addition, the micropore of coal-based AC are developed and the mechanical strength is relatively high, so it has been widely used in the field of flue gas purification[13-14]. While, previous studies failed to learn the influencing factors affecting the mechanical strength of coal-based AC, because the AC type used in the research is more complicated[15]. Therefore, this study takes the coal-based AC commonly used in China as the raw materials to try to clarify the pore structure characteristic index that affects the AC mechanical strength, which provides a theoretical basis for the production and purchase of high mechanical strength AC.