Tubular Crystallizer Research Articles

Batch and Tubular-Batch Crystallization of Paracetamol: Crystal Size Distribution and Polymorph Formation

The crystallization of paracetamol from ethanol and methanol solutions was used to examine the possibility of using rapid cooling in a tubular flow-through apparatus to manipulate crystal size distribution and morphology. Flow through the tubular portion of the apparatus was laminar, and hence, the device, including a receiving vessel, is referred to as a laminar-flow tubular crystallizer (LFTC). Undersaturated solution entered the tubular portion of the LFTC and was rapidly cooled to temperatures far below solubility conditions. Experimental results were also obtained using a typical batch configuration with the same solute and solvents, but with significantly lower cooling rates than in the LFTC. The crystals produced in the flow-through apparatus were of smaller mean size than those obtained from batch crystallizations, and evidence was found that using the rapid-cooling technique could lead to the generation of kinetically stable polymorphs. Moreover, the total run time required to relieve all of the ...

A study of ceramic-lined compound copper pipe produced by SHS–centrifugal casting

In this study ceramic-lined compound copper pipe (CLCCP) was produced by self-propagating high-temperature synthesis (SHS) and centrifugal casting technology. The effects of additives such as SiO 2, CrO 3, Na 2B 4O 7 and ZrO 2 on the densification degree, combining strength and the toughness of the ceramic layer were of prime interest. The results show that the densification degree of the ceramic layer can be improved by adding SiO 2 and CrO 3 in the thermite. This improvement correlated with the reduction of porosity of ceramic layer. The combining strength is increased through the addition of a suitable amount of Na 2B 4O 7. The highest fracture toughness of ceramic layer is obtained at 7 wt.% of ZrO 2 in thermite. The CLCCP shows excellent service properties when it is used in tubular billet crystallizer, including the prevention of cracks and flakes.