Numerical simulation and experimental study on eggshell membrane separation device

Abstract

In order to provide theoretical guidance for separating egg membrane from eggshell by using mechanical agitation, CFD was used to explore the flow characteristics in stirred tank, using the Sliding Grid method to deal with the impeller rotational velocity zone in flow field, and using the Euler model to deal with liquid-solid two-phase flow. This study explored the influence of dish-shape bottom or flat-shape bottom, the clearance size between baffle and the side wall, and the axial height of impeller to bottom on suspension state of particles, solids holdup distribution, solid phase velocity and power number by CFD. Simulation results showed that better particles suspension effect in dish-shape tank can reduce particles accumulation at the bottom and power consumption. If there was a small clearance size (S) between the baffle and the side wall of the stirred tank, it would reduce particles accumulation at the bottom, and reduce the power consumption. However, too large S would decrease the suspension height of particles, not only cannot strengthen the main flow, but also lead to most fluid through clearance forming tangential flow, simulation results showed that S=6 mm was perfect. While decreased axial height of impeller (C) to bottom, particles accumulation at the bottom was decreased, but power consumption would increase, simulation results showed that C=H/5 (H is height of liquid surface) was perfect. According to the simulation results, the structure of the stirring tank was optimized. At the same time, the influences of stirring rotational velocity, stirring time, solid-liquid ratio and separating medium temperature on egg membrane recovery were also studied by experiment, and optimal parameter combination of factors was obtained. The experiment results showed while the stirring time was 17.1 min, stirring rotational velocity was 350 r/min, solid-liquid ratio was 1:17 g/mL, the separating medium temperature was 32°C, the membrane recovery rate can reach above 89%. The device improves the recovery and utilization of discarded eggshell, and provides a reference for the solid-liquid two-phase flow and related study.

Fluid-solid drag models selection for simulating wheat straw particle movement in anaerobic digester

“…Under optimal conditions, it is expected that all biomethane will be transferred from the solid-liquid reaction to the gaseous phase, ensuring maximum energy recovery. Due to the high difference in density of solid biomass particles, the separation of a solid-liquid mixture is inevitable [3,4] . Specifically, this is manifested as the sedimentation and floating of straw particles, which is not conducive to fermentation [5,6] .…”

Advances in eggshell membrane separation and solubilization technologies

“…In 2020, Yuji Hasebe ( 31 ) used the difference in specific gravity between eggshell membranes and eggshells to recover batches of eggshell membranes by crushing, ultrasonic irradiation treatment and separation using a sieve, getting a recovery rate of 85–95%. They also designed a cyclone type airflow cleaning device, and the membrane recovery rate was higher than 94% and the membrane cleaning rate was higher than 96% under the optimal operating parameters ( 33 ). Another method is through dissolved air flotation (DAF) invented by using the different solubilities of water under different pressures, and about 96% of the eggshell membrane can be recovered by the DAF separation device ( 41 ).…”

“…Acid–alkali methods can be divided into acid, base, and acid–alkali combination methods. Acid ( 33 ) methods can use inorganic acids such as hydrochloric acid and acetic acid because disulfide bonds are more stable under acidic conditions and can be used with reducing reagents such as mercaptopropionic acid to extract eggshell membrane proteins. The alkali method usually uses a strong alkali solution such as NaOH to break disulfide bonds or even peptide bonds to obtain a lower molecular weight protein solution.…”

Design and Parameters Optimization of Pteris vittata Automatic Sowing Machine for Phytoremediation

“…The placement angle of the blade has a significant effect on the axial velocity and turbulent kinetic energy in the stirring tank. Through the simulation, it is found that the stirring effect is the best when the blade angle is 45° [8]. A backwater mechanism is designed on the outer wall of the stirring tank.…”

“…According to the test results in Table 2, a response surface regression equation model was established in DesignExpert10.0 software, which takes the distance between the nozzle and plug, the nozzle angle B and the transmission speed C as the independent variable and the uniformity coefficient Y as the objective function. The results are shown in Equation (8). At the same time, the influence of various experimental factors on the uniformity coefficient is obtained by the analysis of variance; the results of the analysis of variance are shown in Table 3.…”