Bubble column crystallizer

Figure 7.12 Bubble column crystallizer according to the Ruttgers patent. [Reproduced with permission from Rittner and Steiner...

The reaction engineering model links the penetration theory to a population balance that includes particle formation and growth with the aim of predicting the average particle size. The model was then applied to the precipitation of CaC03 via CO2 absorption into Ca(OH)2aq in a draft tube bubble column and draws insight into the phenomena underlying the crystal size evolution. 

This mixture is fed into bubble columns and contacted with chlorine gas at 3.5 bar and 115-145 °C [57]. A typical reaction mixture has a composition of 38.5% acetic acid, 11.5% acetic anhydride and 50% chlorine gas. The crude product is first purified by distillation. Thereafter, either crystallization or hydrogen reduction at a Pd catalyst is conducted to separate the monochlorinated from the dichlorinated product. 

Acetica A process for making acetic acid by the heterogeneous carbonylation of methanol in a bubble column reactor. The catalyst is a rhodium carbonyl iodide, anchored by ion-pairing to a polyvinyl pyridine resin. Developed by Chiyoda Corporation and UOP and first described in 1998. Licensed to Guizhou Crystal Organic Chemical Group, China, in 2002 one plant was under construction in 2005. 

Figure 4 shows a schematic of the detector positions in the CARPT Facility which consists of the column, the detector support structure and the signal processing and data acquisition system. The set-up consists of 16 Nal detectors (2.54 x 2.54 cm crystals) positioned around the bubble column at known locations. The column makes use of a Plexiglass plenum which can accommodate test sections of various diameters. A stainless steel porous plate distributor with an average pore size of 40 pim is sandwiched between the two sections. A positioning device was fabricated and attached to the top of the column for calibration purposes. Air to the column is supplied by a compressor and the flow rate is monitored by three parallel rotameters. 

Dry NHj gas (passed through a drying tube packed with CaH ) was bubbled slowly through a solution of 2,6-dichloro-9-(2,3,5-tri-0-acetyl-/ -D-ribofuranosyl)purine (1.0 g, 2.2 mmol, dried at 60 C in vacuo) in anhyd DME (20 mL, distilled directly from NaH into the dried reaction flask) at rt for 8 h. The solution was evaporated and the colorless residue was treated with CIICI3 (10 mL). This suspension was applied to a column of silica gel (50 g, 2 x 45 cm). CHClj/acetone with an increasing gradient of acetone was used for elution. The appropriately pooled fractions were evaporated and the resulting colorless solid foam was dissolved in CHCI, /i-PrOH. The product crystallized upon slow evaporation of the solution. It was filtered, washed with EtjO, and dried yield 857 mg (91%) mp 151-152°C. 

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