Study on the Flow Characteristics of Desulfurization Ash Fine Particles in a Circulating Fluidized Bed

Abstract

In view of the current status of catalytic cracking flue gas treatment, it is necessary to study the flow environment of desulfurization ash particles, which are a type of Geldart C particle, in a circulating fluidized bed (CFB) for semi-dry flue gas desulphurization using CFB technology. This study investigated the flow characteristics of desulphurization ash particles in a riser with an inner diameter of 70 mm and a height of 12.6 m, at a gas velocity of 4–7 m/s and a solids circulation rate of 15–45 kg/m2·s. The solids holdup in the axial distribution is relatively high near the bottom of the riser, and gradually decreases as the riser height increases, with a stable value from the middle to the top of the riser. In the radial distribution, the solids holdup of desulfurization ash particles is low in the center and high in the wall region. Within the above operating conditions, the solids holdup ranges from 0.008 to 0.025. The particle-based Archimedes number has a linear relationship with the solids holdup at all operating conditions.

Fast pyrolysis of birch wood in a bubbling fluidized bed reactor with recycled non-condensable gases

“…Although the existing CO atmosphere promoted the reaction of oxygen in the vapor, transferring it into NCG, other gases (H2, CH4, and CO) and temperatures may have a decisive effect on the bio-oil yield. Similar effects of the final pyrolysis temperature on the yields of products were achieved in other studies (Pattiya 2011;Abraham et al 2013;Wang 2015). In these studies, various types of organic wastes were used in different reactors.…”

“…The pressure loss was caused by pipe friction drag and Fanning friction factor due to filler in the preheater section of the reactor. For P4, the fluidizing pressure difference was 60 Pa, which was slightly higher than the value in a previous study (Wang 2015). P5 was -1410 Pa. After feeding the biomass, all pressure values except P4 increased sharply due to the continuous increase of NCG.…”

Measuring Technologies for CFB Solid Circulation Rate: A Review and Future Perspectives

“…This method can give a convincing result of local particle velocity but not average velocity, which depends on velocity distribution. In the method established by Yang et al [45], the local density is measured along with velocity in an optical fiber probe, which makes it applicable in dilute phase areas. For industrial equipment, the velocity distribution becomes more uneven because of larger size, which leads to larger error.…”

Sulfur Migration Behavior in Sintering and Pelletizing Processes: A Review

“…In addition, the materials separated from the gas and solid by the dedusting equipment can be returned to the bed through the circulating system for recycling. [78][79][80] This method had a high desulfurization efficiency and no wastewater discharge, with advantages such as a low investment intensity. [69] The main reactions are given by…”