| Resumo: |
Vanillin is a popular flavor in the food industry. Lignin oxidation had been the main route for vanillin production since the sixties. Pulp industry is the most important source of quasi-pure lignin. Lignin from gymnosperms is the most appropriate raw material for the production of vanillin since it consists of guaicyl-propane units, which are the precursors for vanillin yield.
There have been many studies with regard to lignin oxidation conducted at LSRE. Kinetic schemes have been developed and published (Mathias, 1993). During the course of the reaction, the vanillin product also undergoes oxidation (Fargues et al., 1996). Optimum reactor conditions have also been obtained for vanillin yield (Fargues et al., 1996). An optimal vanillin yield was obtained in a batch reactor at an oxygen partial pressure of 2.8 bar, temperature being 133 C and at an initial lignin concentration of 60 g/l. Another project titled, "Production of vanillin from lignin - process development" was also completed recently at LSRE. This project mainly concerned the lignin oxidation in a structured bubble column reactor. There are many issues involved in process development. So far, the projects put thrust on reaction engineering aspects. A study on the retention of vanillin on a classical cationic resin, Duolite C20 was carried out in our laboratory by Mathias et al. (1993). The capacity for the resin was very low. As vanillin is in the form of an anion in solution, it may be intuitive to try to exchange it with an anion exchanger.
Separation of vanillin from the lignin oxidation broth holds the key for technology transfer. This project tries to solve this problem. To this end, the following tasks are being planned: Equilibrium adsorption studies, Batch kinetic studies, Fixed bed adsorption, Ultra filtration.
One aspect which is note worthy is that vanillin yield depends on the quantity of precursors in the lignin. Models will be developed to substantiate the experimen  |
Resumo
Vanillin is a popular flavor in the food industry. Lignin oxidation had been the main route for vanillin production since the sixties. Pulp industry is the most important source of quasi-pure lignin. Lignin from gymnosperms is the most appropriate raw material for the production of vanillin since it consists of guaicyl-propane units, which are the precursors for vanillin yield.
There have been many studies with regard to lignin oxidation conducted at LSRE. Kinetic schemes have been developed and published (Mathias, 1993). During the course of the reaction, the vanillin product also undergoes oxidation (Fargues et al., 1996). Optimum reactor conditions have also been obtained for vanillin yield (Fargues et al., 1996). An optimal vanillin yield was obtained in a batch reactor at an oxygen partial pressure of 2.8 bar, temperature being 133 C and at an initial lignin concentration of 60 g/l. Another project titled, "Production of vanillin from lignin - process development" was also completed recently at LSRE. This project mainly concerned the lignin oxidation in a structured bubble column reactor. There are many issues involved in process development. So far, the projects put thrust on reaction engineering aspects. A study on the retention of vanillin on a classical cationic resin, Duolite C20 was carried out in our laboratory by Mathias et al. (1993). The capacity for the resin was very low. As vanillin is in the form of an anion in solution, it may be intuitive to try to exchange it with an anion exchanger.
Separation of vanillin from the lignin oxidation broth holds the key for technology transfer. This project tries to solve this problem. To this end, the following tasks are being planned: Equilibrium adsorption studies, Batch kinetic studies, Fixed bed adsorption, Ultra filtration.
One aspect which is note worthy is that vanillin yield depends on the quantity of precursors in the lignin. Models will be developed to substantiate the experimental results. There are some missing physical and chemical property data. These can be estimated by simulation and modeling software. Once these are in place, a flow sheet will be developed and simulated using HYSYS. This activity will lead to the basic process engineering package. |