Kinetic model of soda black liquor oxidation under pressure

Abstract

Soda black liquor is a complex chemical system containing various classes of organic and inorganic compounds dissolved in water at alkaline pH. Upon contact with oxygen under elevated temperature and pressure, a stagewise oxidative degradation of organics occurs. A simple model, based on a three-lump component, has been proposed in order to simulate the kinetic behavior of the original system in terms of total dissolved solids, chemical oxygen demand, and carbonate content of solution changes with time. Experimental data obtained in a series of batch and continuous autoclave runs have been closely approximated with three finite algebraic expressions containing two fixed reaction rate constants and one adjustable parameter.

Kinetics of Vanillin Production from Kraft Lignin Oxidation

“…However, no kinetic study was undertaken as far as we know. In two cases attempts of modeling were done, considering a firstorder reaction rate of vanillin production with respect to the lignin concentration (Nadezhdin and Robertson, 1990;Adachi et al, 1992); however, the influence of oxygen partial pressure was not discussed.…”

Green chemicals from pulp production black liquor by partial wet oxidation

“…PWO is carried out by controlling the oxygen supply to the WAO process. This process is used for the recovery of short chain organic molecules, such as carboxylic acid anions (Nadezhdin, 1988) or for increasing the biodegradability for further biological waste water treatment (Dudala et al, 2014). In this process, some of the components react completely and some are oxidized to a smaller extent at low temperature and pressure.…”