Search

A horizontal dilute-phase pneumatic conveying system using vertically oscillating soft fins at the inlet of the gas–particle mixture was studied to reduce the power consumption and conveying velocity in the conveying process. The effect of different fin lengths on horizontal pneumatic conveying was studied in terms of the pressure drop, conveying velocity, power consumption, particle velocity, and intensity of particle fluctuation velocity for the case of a low solid mass flow rate. The conveying pipeline consisted of a horizontal smooth acrylic tube with an inner diameter of 80 mm and a length of approximately 5 m. Two types of polyethylene particles with diameters of 2.3 and 3.3 mm were used as conveying materials. The superficial air velocity was varied from 10 to 17 m/s, and the solid mass flow rates were 0.25 and 0.20 kg/s. Compared with conventional pneumatic conveying, the pressure drop, MPD (minimum pressure drop), critical velocities, and power consumption can be reduced by using soft fins in a lower air velocity range, and the efficiency of fins becomes more evident when increasing the length of fins or touching particles stream by the long fins. The maximum reduction rates of the MPD velocity and power consumption when using soft fins are approximately 15% and 26%, respectively. The magnitude of the vertical particle velocity for different lengths of fins is clearly lower than that of the vertical particle velocity for a non-fin conveying system near the bottom of the pipeline, indicating that the particles are easily suspended. The intensities of particle fluctuation velocity of using fins are larger than that of non-fin. The high particle fluctuation energy implies that particles are easily suspended and are easily conveyed and accelerated. [ABSTRACT FROM PUBLISHER]

The effect of using the soft fins on a horizontal pneumatic conveying of granular particles in various curved 90° bends was studied in this paper, in order to reduce pressure drop and conveying air velocity. Experimental measurements were performed in terms of the pressure drop, conveying air velocity, power consumption and additional pressure drop. The distributions of particle velocity near and in the curved 90° bend were measured by high-speed PIV. The test pipeline consisted of a 4.5 m-long horizontal straight acrylic tube, a curved 90° acrylic bend and a 1.5 m-long horizontal straight acrylic tube, having an inside diameter of 80 mm. The polyethylene particles with diameter of 2.3 mm were used as conveying materials. The superficial air velocity was varied from 10 to 14 m/s, and the solid mass flow rate was fixed at 0.45 kg/s. Comparing with the dilute phase pneumatic conveying, the pressure drop, the minimum pressure drop (MPD) velocity, power consumption and additional pressure drop can be reduced by using soft fins for various bends in lower air velocity range. The reduction becomes more evident with increasing the radius ratio of bend. The maximum reduction rates of the MPD velocity and power consumption by using soft fins is about 8.2% and 11.7%, respectively. At the upstream of bend, the particle velocity of the soft fins is evidently higher than that of the dilute phase in the bottom part of pipe for all bends. The effect of soft fins on the particle velocity and its fluctuating energy still remains in the bend and the downstream of bend, and the fluctuating energy of particle velocity gradually decreases through the bend. At the downstream of bend, the fluctuating energy of particle velocity decreases with increasing the radius ratio of bend. [ABSTRACT FROM AUTHOR]