Microwave heating enhanced distillation and concentration of sulfuric
acid under vacuum
Abstract
A novel microwave heating flash evaporation system (MWHFES) was carried
out to concentrate and distillate sulfuric acid, and this system may
overcome the problems that equipment corrosion, product pollution, high
energy consumption, long process and lower heat transfer rate in waste
sulfuric acid recycle though purification and concentration. The dilute
sulfuric acid with mass fraction of 75wt% was used as experimental
material, 5 experimental cases was generated to verify the effect of
MWHFES under the conditions of different volume, microwave power and
depressurization rate. Results shown that the sulfuric acid could be
concentrated to mass fraction of 85-95%, and the heating efficiency was
among 30% to 80%, heat transfer volume coefficient was among 100 to
500 though the combination of vacuum and microwave heating. Thermal
process analysis indicated that the interaction among experimental
factors had effect on distillation process. At last, the process
optimization and selection were explained briefly.