Nonlinear Oscillations in Continuous Crystallization Processes

摘要: Crystallization is often viewed as an art not a science, perhaps because it one of the most difficult unit operations to understand. It technology used isolate solids from liquid phase melts or solution. In chemical industry efficient separation processes for production organic and inorganic chemicals. bulk scale conducted in form continuous process small batch high purity Despite its importance, still poses some problems. The work covered this thesis motivated practical operational problems existing industrial crystallizers. solution characterized by CSD (crystal size distribution), i.e. generation wide spectrum differently sized crystals. During crystallization processes, mainly determined number simultaneously occurring kinetic within crystallizer. main are nucleation crystals, subsequent growth crystals well breakage rate equations these usually nonlinear. This nonlinearity can lead complex dynamic behavior like self sustained oscillations. will poor product quality, yield loss, loss further downstream processing product. Analysis previous researchers reveals two different explanations oscillating behavior, i.e order cycling low [72, 73]. High induced due non-linearity at exponents. Low occurs exponents when crystallizer operated with classified removal fines dissolution. Fines dissolution employed achieve coarser crystalline narrow CSD. produce controlled specific crystal length crystallizer, classifier used. goal predict regions parameter space operating conditions physical properties where instability using numerical bifurcation stability analysis. For doing analysis model necessary describe processes. A derived DTB (draft tube baffle) Chapter 2 based on first principles. comprise dispersed phase. PBE (population balance equation) introduced Hulburt & Katz [25] describing evolution mass