From Macro Batch to Micro-conti Manufacturing: A New Eco-Friendly Production Process for Writing Ink Employing Micro-process Engineering

A method is proposed for the transfer from a batch production process for writing ink to continuous manufacturing by employing micro-process engineering. Special challenges arise from handling reactant streams with solids, high viscosities and flow ratios, which differ significantly from unity. Four different types of micromixers are tested by optimizing mixing effectiveness versus operational robustness. For the best suited mixer, a 48 h continuous production run is performed producing ink within specification at all times. A significant reduction of the plant hold-up is achieved for the conti manufacturing plant in comparison with the batch process. Initial cleaning experiments suggest that the specific wastewater production may be reduced by a factor of 1000 through micro-conti manufacturing.