Sepharose is a carrier for preparation of the protein A immunoadsorption column,and its industrial-scale process of activating reaction has been the key issues of batch production for the blood purification material.In the activating reaction process of the sepharose,the optimization and scale-up technology of the stirred tank reactor is a crucial factor to industrial processes.Although there are a number of experimental and theoretical studies for stirred tank reactor,the relative theory and design method is still not perfect.In recent years,researches on flow and mixing characteristics of stirred tank reactor by using Computational Fluid Dynamics method has shown remarkable advantages,and leads the development of mixing techniques.In this paper,the single-phase flow field is simulated with standardκ-εturbulence model and multi-reference frame method of steady-state flow using FLUENT software.To verify the feasibility of the CFD,the results are compared with the experimental data of literature.Then the single-phase flow field of sepharose is simulated.Through the researches of the flow pattern, velocity field and shear force field under the different type impellers conditions,it is found that 45°pitched blade down flow turbines(PBTD45) impeller has higher circulation flowrate and lower shearing effect,its performance is superior to rushton disk turbine(DT).So the PBTD45 impeller is recommended for the activating reaction of sepharose.The suspended characteristics of solid-liquid in stirred tank reactor,as solid catalyst and sepharose,are simulated in this paper.Through the researches of solid phase suspended performance,it is found that PBTD45 is superior to DT and PBTU45.Just-suspended impeller speed of the three impellers is respectively simulated as 948rpm,570rpm and 1152rpm,and the results are compared with the Zwietering correlation.The maximum relative deviation is 13.4%. In conclusion,the optimal operating conditions for activating catalyzed reaction of sepharose in 20L stirred tank reactor are:with PBTD45 impeller,N=570rpm and D=0.10m.Additionally,artificial neural networks(ANN) technology is introduced,with MATLAB as a software platform,to establish a prediction model for sepharose activated reaction,which is a 3-layer BP network structure.The predictions for two experimental conditions,shaked flask and stirred flask,are respectively made using ANN models.Compared to the experimental data,the average absolute relative deviation is less than 6%. Finally,scale-up technology of bioreactor for preparation of blood purification materials is studied.Then the large scale biorcactor is simulated and optimized,which can provide some theoretical basis and design guidance for bioreactor optimization design and scale-up.
Post about "stirred tank reactor"
High-molecular weight esters from long-chain alcohols and long-chain acids are typically referred to as wax esters.The novel characteristics,such as excellent emollient behavior of wax esters have maximized their usage in various industries.They are used in foods, personal care,metal working fluids,rolling oils and synthetic lubricants. However,the main obstacle to large-scale use of natural wax ester is its cost and availability.Thus,attempts to synthesize wax esters with cheaper starting materials and shorter time have become very important. Interest in lipase-catalyzed preparations of wax esters has grown due to the possibility of obtaining a wide variety of high-quality products under mild reaction conditions utilizing the substrate selectivity of such biocatalysts.Furthermore,the growing demand for the environmentally friendly processes,has widened the use of enzymes as biocatalysts. In this paper,wax ester was synthesized from soybean oil and cetyl alcohol in a packed-bed reactor with petroleum ether as solvent and immobilized lipase Candida sp.99-125 as catalyst.The effects of the height of packed-bed,flow rate of reactant,dosage of immobilized lipase,molar ratio of substrate were investigated.The optimum conditions were as follows:immobilized lipase 47g,the height of packed bed was 40cm(diameter 3.5cm),the molar ratio of oil to cetyl alcohol was 1:2.4,the flow rate of reactant was 4mL/min and the retention time was 4h,the yield of wax ester reached 83%.The stability of the immobilized lipase was also studied,and the yield remained above 70% after 16 batches.The packed mode of the immobilized lipase in reactor was discussed.Wax ester was synthesized in a stirred tank reactor in solvent-free system.The effects of the molar ratio of substrate,dosage of immobilized lipase,stirring speed were investigated.The optimum conditions were as follows:immobilized lipase 2.5%W oil,the molar ratio of oil to cetyl alcohol was 1:2.25,the stirring speed was 150-200rpm(Corresponding Reynolds number was 294-392),the yield of wax ester reached 74%.The yield increased by adding cetyl alcohol and immobilized lipase in 4 batches.Immobilized lipase could reused that can reduce the cost.The purification of crude product was also investigated.The processing conditions of removal alcohol and acid was confirmed.The purity of products reached 95%,the yield of purification was 92%. Tested some performance indexes of products,the result showed that the product from experiment has high viscosity,high flash point,good thermal stability and moisture retention which can be used in lubricant and cosmetic.The composing and performance of products was similar to natural wax ester,could used as substitute of natural wax ester.