Hydrothermal co-liquefaction (HTCL) is the prominent process for producing
bio-products with a higher conversion rate. It is performed at high
temperatures and pressure in the presence of water. Earlier, it was mostly
conducted in batch reactors, but it has major limitations including
operating volume, back mixing and tedious process for high productivity.
With that, the present investigation is performed on designing the screw
shaft for the high-pressure HTCL process. The dimensional factors including
flight length, pitch, helix angle and depth were considered to design the
optimal screw shaft. Likewise, principal stresses, shear stress, bending
stress, bending moment and total deformation were regarded as inevitable
response variables to analyze the internal strength of the shaft. In this
regard, the Taguchi approach provides the L9 (34) orthogonal array as an
experimental design. Then, the numerical results from the transient
structural analysis were analyzed with the assistance of statistical methods
such as Grey Relational Grade (GRG), Grey Fuzzy Reasoning Grade, Analysis of
Variance (ANOVA) and Taguchi method to find the most influential dimensions
for minimizing the response variable. Consequently, the results from both
GRG and Taguchi optimization were compared and selected the most optimum
parameters.