For more than a decade, the production of Bioethanol has been moving towards so-called ‘second generation’ processes. While ‘first generation’ plants use raw materials that are part of the food chain (e.g. sugar cane, corn, etc.), the new concept provides that the source of cellulosic biomass comes from waste products of the agro-food industry (e.g. various types of straw, processing by-products, etc.), thus maximising the value of the total crop.
Diemme® Filtration has numerous references for these applications in various parts of the world where the availability of waste biomass is abundant and where there is an incentive to reduce the use of fossil fuels.
The close collaboration with customers and with groups that have patented various cellulosic Bioethanol processes in this field has allowed the inclusion of the filter press as a solid-liquid separation technology in various production steps.
Diemme Filtration technology in the Second-generation Bioethanol production flowsheet
A general flowsheet for Second-generation Bioethanol production could be composed of the following steps: PRETREATMENT – Solid/liquid separation – ENZYMATIC HYDROLISIS – Solid/liquid separation – ALCOHOL FERMENTATION – Solid/liquid separation – DISTILLATION – Solid/liquid separation.
The characteristics of the starting materials (all of which have a strong cellulose matrix) are important parameters in determining the applicability of the filter press which, among the industrial sludge treatment technologies, is the one with the highest degree of separation. In particular, after alcoholic fermentation, it allows the greatest amount of ethanol to be recovered.
One of the most frequent points of use of the filter is downstream of the distillation column, where the solids (rich in lignin) need to be dehydrated as much as possible in order to be dried and used as fuel. The increased dehydration of lignin leads to savings in thermal drying costs.
The wide range of products, combined with very precise processing choices, have allowed Diemme® Filtration to be a reference partner for this particular expanding market.