Numerical Simulation And Experimental Studies Of The Separation Of The Starch Granules Containing Pea Protein Slurry In The Micro-hydrocyclone

The main components of pea are starch and protein,in which the starch content is 40%~45%,the protein content is 20%~25%,and the crude fiber content is 8%~12%.In the preparation of pea protein,most of the fiber residue and starch could be removed by grinding and filtration of pea slurry,but the pea protein slurry still contained a small number of starch particles.Removing starch with a hydrocyclone could improve the protein content of pea protein products.At the same time,the hydrocyclone was operated in a fully closed condition,which could prevent the slurry from contacting with oxygen and reducing the bean smell.The spin separation of pea protein slurry contained starch granules was studied by numerical simulation and experiment.Firstly,according to the existing hydrocyclone structure in the laboratory,Reynolds stress turbulence model(RSM)was suitable for high-speed vortex spiral flow and selected to calculate the turbulent motion of the fluid in the hydrocyclone.The particle Rosin-Ramler(R-R)distribution and Discrete Phase Model(DPM)were used to simulate the motion of the subphase insoluble components in pea slurry.The internal flow field model of the hydrocyclone was divided into a high-quality hexahedral grid by using the computational fluid dynamics pre-processing software(Icem-cfd),and a certain boundary condition was used in the computational software(Fluent)for computer numerical simulation.By comparing the calculated results of pressure field,velocity field and discrete phase particles with the previous results and experimental results,it was proved that the model and numerical calculation method adopted in this paper were reasonable and reliable.On this basis,computer numerical method and the response surface method predicted the internal flow field of hydrocyclone and separation efficiency of the single and interaction with inlet velocity(A),inlet starch concentration(B),spilt ratio(C)and inlet protein concentration(D)obtaining different operation parameters of internal flow field distribution features and the quadratic polynomial regression equation of separation efficiency.The relative error of the prediction ability of the regression equation model to the separation efficiency of insoluble(starch)components was less than 10%.The relative error of the separation efficiency of soluble(protein)components was less than 15%.The separation of the single-stage hydrocyclone was investigated.Pea protein slurry contained starch granules was prepared by anaerobic pulping and screw slag removal method.The slurry with different protein content and the same starch granule content was obtained by controlling the water mass ratio of 1:7,1:5and 1:3.It was found that the higher the protein concentration in the slurry,the separation efficiency of insoluble(starch)components was less,and there was no significant difference in the separation efficiency of soluble(protein)components.When the feed velocity was greater than 18.92 m/s(or the inlet pressure was greater than 0.5 MPa)and the spilt ratio was 0.3,the ratio of the protein in the overflow to the total protein and the ratio of the starch in the bottom flow to the total starch could reach more than 80%.Changes in operating conditions would reduce overall separation efficiency.In order to achieve the goal of minimizing starch content and protein loss in the slurry,a three-stage hydrocyclone device with a processing capacity of 1.6 L/min was designed and assembled,and pea slurry was separated on this equipment.The results showed that the protein content was 85% and the protein recovery was over 90%.