Design and fabrication of a feedstock delivery system for a 3 kW solar gasification reactor

Abstract

In the present work, a feed delivery system for a solar gasification reactor was designed, fabricated and tested. The feedstock delivery system delivers the required amount of feedstock into the reactor which is a cavity of molten salt held at 1200K. The feed delivery rate was from 8±(0.4) gm/min to 15(±0.75) gm/min. The cellulose feed particles were of diameter 0.5mm. The feed delivery system is comprised of hopper, screw feeder, stepper motor and feed injector. The hopper was designed to store a feed supply needed for continuous one hour operation of the reactor at the feed delivery rate of 15(±0.75) gm/min. The screw feeder, which is rotated using a stepper motor, draws the feed particles from the hopper outlet and carries them in forward direction to the feed injector. The feed injector was designed using the principle of dilute phase pneumatic transport theory which takes into account the feed particle size and feed delivery rate. It is interfaced with the reactor and it carries the feed particles to the reactor cavity with the aid of a nitrogen gas flowing at a speed of 12 m/s. Cellulose feed particles tend to become mushy at temperature above 473 K; thus clogging the feed supply line. This clogging prevents the supply of feedstock to the reactor. To prevent clogging temperature of the feed supply line was kept below 473K using air jets impinging on the feed supply tubing. A Labview control scheme was designed to control the input to the Mass Flow Controllers (MFC) and to monitor and write the outputs from temperature and pressure sensors. Output signals were logged at a frequency rate of 1000 samples per minute.