Engineering Enlargement Study On Polypropylene Horizontal Stirred Bed Reactor

The SPG polypropylene process has been successfully developed by China and owns self-intellectual property rights. The excellence of this process is obvious, such as good quality of the product, low consumption of energy and raw material, and great potential in the development of special polypropylene grade. However, the scaled progress and application of the process has been limited due to the lack of engineering investigation on the core equipment of horizontal gas phase stirred reactor.This study has made great effort to the engineering enlargement on horizontal reactor with systemic research, based on multi-methods of process simulation study, fundamental research in lab and engineering design investigation. The main progress and conclusions are as follows:It has been pre-estimated exactly the thermodynamics and kinetics properties in reaction system via PC-SAFT equations of state on the platform of Polymers Plus process simulation software. While, it has also been specified the residence time and the relevant technological design parameters of the horizontal gas phase stirred reactor, due to the combination of SPG process simulation result and engineering experience.The flow characteristic has been studied in the cold model experimental apparatus. The residence time distribution of different blades (leafe blade, T type blade and door type blade) has been measured, then the impact on residence time was studied under different situation such as with baffle, without baffle and changing incline angle of baffle. It has been analyzed the back mixing and flow pattern of horizontal reactor under different internals configuration by the method of CSTR in series model and back mixing model, which prodived theoretical instruction and the basis for the style selection of blade and the design of internals. The agitation characteristic of three kinds of blades has been researched via the experiment. The agitation shaft powers were measured with air blow and without air blow, therefore the impact on power of rotational speed, feeding coefficient and blow flow flux were discussed. The power number of the different blades has been empirical regressed by introducing nondimensional number such as velocity number, feeding nubmer and powder properties, thus the agitation shaft powers empirical correlation equation was obtained. The result showed that the accuracy can satisfy the need of engineering enlargement. The paper also studied the level distribution character. The acoustic emission signals coming from the solid particles striken on the wall was detected through the acoustic emission (AE) measuring device. The accuracy and reliability of acoustic emission (AE) technique has been testified based on the cold model in lab and hot model in industry. Thus, a new method to measure the level of industrial polymer reactor was proposed.Accroding to process parameters achieved by process simulation, fundamental research result in lab and empirical regression formula of powers number, the reaearch on the engineering enlargement of horizontal reactors has been implemented and it was determined that the outside dimensions, agitation power, internals arrangement, agitator type and level detection method of the reactor.The above reaseach not only systematically mastered the engineering enlargement criterion and key technology of polypropylene horizontal reactor, which provided the design basis for the engineering design of large-scale horizontal reactor, but also can provide the possibility of the developement of special polypropylene grade and the instruction to the new catalyst appraisal. Furthermore, the industrial applicaiton of the SPG process has been accelerated, and it is signaficant on scaled progress of this technology and the development of polypropylene production in petrochemical industry.