Figure 1. Schematic diagram of experimental setups
The ancillary equipment for the whole experimental system includes the gas and liquid flowmeters, air compressor, liquid pump, and water tank. All experiments done in this study are in the cold flow manner, and the gas, liquid and solid phase are air, water and spherical particles, respectively. Provided by the air compressor, the gas is metered by the rotameters and enters radially into the bed through the gas distributor. The water, pumped by the multistage pump, is metered by the electromagnetic flowmeter then evenly sprays into the column on the top of the particles through the nozzles. Spherical particles with an average diameter of 2.4 mm, saturated water absorption of 21% and a bulk density of 1.04 g/cm3, are continuously added into the top of the bed from the silo. This reactor operates in a downflow state: the gas, liquid, and solid phases flow cocurrently downward through the bed after pre-distribution and exit from the bottom of the bed. The outlet pipe is open to the atmosphere to vent out the air. The solid flow rate is controlled by a gate valve on the central outlet pipe and measured by weighting. To identify the solid flow rate, first, collect and weigh all the liquid and solid flowing out within a certain time, and then subtract the liquid to obtain the mass of saturated water-absorbing particles. It is worth saying that the mass of liquid flowing out of the bed is easy to be acquired by the liquid flowmeter since the mass of liquid flowing out of the bed in unit time is equal to the liquid injection rate in a steady state. The experiments are carried out at room temperature (25±1℃) and near atmospheric pressure. The range of the operating conditions in this study is shown in Table 2.