Influence of geometric parameters of screw nozzles of a twin screw extrusion press on the oil output

Abstract

The relevance of the study is due to the search for rational geometric parameters of screw nozzles and the identification of the influence of the compression ratio of twin screw extrusion presses on the oil compression process. An important criterion in this paper is the indicator of the value of oil yield to obtain economic profit. From the analysis of optimisation methods in similar studies, the following variable geometric parameters of screw nozzles were selected for twin screw extruders: axial pitch, channel width between turns, rig width of the turn, and nozzle length. Two sets of experimental working bodies with modified geometric parameters were manufactured based on theoretical calculations and computer modelling to improve the working bodies of the EK 75/1200 twin screw extrusion press. Their theoretical compression ratio is determined, which is 5.50 and 4.33, respectively. It is also defined for the basic set of working bodies, which was recommended by the manufacturer, which was 4.69. It is established that the general nature of changes in the free volume along the length of the screw shaft is accompanied by an uneven decrease from 40 to 80% toward the press cake output. From the reviewed scientific literature, it was identified that the nature of changes in the free volume of turns along the length of the screw shaft characterises the correctness of its design. However, after analysing the results of the work performed, it was determined that the selection of rational geometric parameters of the working bodies should be considered in conjunction with other structural parameters, which will further intensify the oil compression process. It is experimentally confirmed that the oil yield depends on the degree of compression due to the geometric parameters of the screw nozzles. The oil yield increased by 0.9% when using a set of working bodies of set 1 when compared with the basic set of working bodies from the manufacturer’s factory (set 2) in terms of volume of processed raw materials per unit will bring additional profit. It was determined that with the production volume of 50 tons of oil with an improved set of working bodies (set 1), the economic effect amounted to UAH 19,250