Study On Continuous Production Technology And Equipment Design Of Calcium Stearate At 5000t/a

Calcium stearate,as a non-toxic and biocompatible organic salt,was used widely in the heat stabilizer of PVC,flame retardants for polymer materials,lubricant for mechanical processing and cosmetics.In addition,calcium stearate could also be used as emulsifier and flat agent for paint,waterproofing agent for building materials,thickening agent for washing products and so on.In this paper,we analyzed the processes routes of industrial production of calcium stearate,such as melt method,metathesis method and saponification method and choose melt spray method as processes routes of calcium stearate which was improved and optimized.Stearic acid and calcium hydroxide were melted at 165 ?,and then the appropriate amount of hydrogen peroxide were added and mixed thoroughly to carry out spray reaction to provide the product.Considering the effects of material ratio,melting temperature,the amount of hydrogen peroxide,the reaction pressure on the product quality,we obtained the optimum experimental parameters through orthogonal experiment.The calcium content,free acid content,heating reduction,melting point of the calcium stearate product were 6.7%,0.39%,1.5%,149~154 ? respectively,and in line with national standards.The calcium stearate from the improved melt spray process and the metathesis process,respectively were characterized through the infrared spectroscopy,morphological characterization,sieving experiments,the thermo-gravimetric analysis and the test of the thermal stability of PVC.The results show that the thermal stability of calcium stearate from the improved melt spray method is relatively better,and particles are uniform.The product quality is better than the calcium stearate prepared by the metathesis process,so the technology is feasible.According to the improved melting process and lab experiment,we designed the continuous production technology at 5000 tons/a which include the design of the technological scheme,the design of the process flow,the drawing of the flow chart,the material balance and the energy balance were carried out.At the same time we designed production technology and selected in detail the technological equipment,such as the melting kettle,the pipeline mixer,the spray tower and the powder cooler,and the layout plan of the workshop was drawn.According to the production technology and production equipment,thedetailed design of automatic control was designed to ensure the production technology of continuous and automatic.The rationality of the technology equipment was verified by three-dimensional numerical simulation of the spray drying process.Based on the analysis of the continuous phase and the discrete phase in the spray tower,the physical information of the velocity field,the temperature field,the humidity field of continuous phase and the residence time,the water content,the diameter of the discrete particles in the spray tower are obtained.The simulation results are basically the same as the lab experiment and technology calculation.The location of the sticky wall of possible was found in the spray tower and the solution is proposed.The influence of the spray pressure and the amount of the liquid treatment on the particle diameter is investigated.which have a certain guiding significance for industrial production.The improved and optimized melt spray production technology solved sucessfully some problems,such as the batch production,“paste pot” from melting kettle,the large sewage discharge and realized the continuous and automatic production of calcium stearate,shorten the production cycle,reduced the particle size of the product,improved the purity of product,diminished the cost of production in our work.