Particle charging and conveying characteristics of dense-phase pneumatic conveying of pulverized coal under high-pressure by N-2/CO2

摘要

The particle charging and conveying characteristics of pulverized coal under high-pressure dense-phase pneumatic conveying were investigated experimentally using CO2 and N-2 as carrier gas, respectively. A novel sensor was designed through a combination of EST sensor and ECT sensor to simultaneously obtain the information of the electrostatic charge and volume concentration of pulverized coal. Experimental results indicated that the increment of the conveying pressure difference could cause the changes of flow pattern from laminar flow to suspension flow for both CO2 and N-2. The volume concentration of pulverized coal conveyed by CO2 was greater than that by N-2 under the same conveying pressure difference, and the same conclusion can be obtained for the mass flow rate. The significant difference with CO2 and N-2 as carrier gas was found and defined in term of the charging characteristics of pulverized coal. The change of charging intensity of pulverized coal exhibited the converse trend for CO2 and N-2, which indicated that the carrier gas played an important role in the particle charging of dense-phase pneumatic conveying. A comparison was made further for the relationship between volume concentration and charge intensity of pulverized coal, which was proved to be negative correlation for both CO2 and N-2. (C) 2018 Elsevier B.V. All rights reserved.