Scale-up of batch esterification of pyrolysis oils with higher alcohols from 250-ml-scale to 20-l-scale

Within the framework of the PyroMar collaborative project about the production of low-sulphur bio-based blendstocks for marine fuels, the esterification of condensates resulting from ablative fast pyrolysis of 2nd generation biomass with higher alcohols derived from lignocellulosic ethanol is investigated. To examine the scale-up of the chemical process three different experimental setups are used: a 3-neck-flask of 250 ml nominal volume, a 3-neck-flask of 2 l and a stirred tank reactor of 20 l. In all setups identical reaction mixtures (relative amounts of pyrolysis oil, butanol and solid acid catalyst) under the same conditions (external heating, operation under reflux, reaction end point indication) were converted and the product mixtures were analyzed. While the smallest setup needed only about 6 hours of operation to reach the end point, the two larger setups required 20 hours. The remaining water mass fraction in all experiments regardless of size and original water content was around 1 wt.-% and the acetic acid mass fraction could be reduced to half the value of the reaction mixture. Further scale-up to cubic metre scale for industrial production seems easily achievable.