PJH Partnership specialises in the application of superheated and supercritical technology to processes involving impregnation, extraction, fractionation and separation. The Ajax inclined stainless steel screw is being used to convey biomass immersed in an organic solvent bath to alter the surface chemistry of the biomass particles. The conveyor features an oil heated jacket and is operated at a pressure of 10 bar. It is compliant with Pressure Equipment Directive (PED) category III and rated for ATEX Zone 1 internally and Zone 2 externally.
The screw is inclined at 30° to the horizontal. “Operating a screw inclined at greater than 20° presents a number of challenges and can significantly reduce the conveyor’s handling capability,” says Ajax technical director Eddie McGee. “When a screw is inclined material tends to fall back into the prior pitch space, dramatically increasing the cross sectional loading of the conveyor as the angle of the screw is now below the contact friction angle of the material. Inclined screws can be successfully operated through the use of specially selected flights and appropriate rotational speed to generate effective radial pressure to drive the material forward.”