Abstract

In the present the oil industry provides the greatest majority of the raw material necessary for the production of chemical products, textiles, pharmaceuticals, and fuels. Countries with no oil reserves, like Chile, have the necessity to seek new cleaner and sustainable technologies to fulfill with its requirements. Lignocelullosic biomass has the potential to replace oil as the raw material to produce chemicals and fuels under the concept of biorefinery. To develop this new concept of industry the Bioenercel Consortium S.A. has designed a strategy for the production of bioethanol, bio-oil, and biomaterials. This strategy includes the bench scale research together with the pilot plant design and operation. The pilot plant includes a wood digester (CRS Reactor Engineering, Sweden) of 88L total capacity with a circulation loop for agitation and temperature control. It also has a liquor displacement option which allows interchanging liquors during cooks. The digester can process up to 15 kg of dry biomass per batch, which can be chips or sawdust. After cooking the wood chips are defibered, centrifuged and placed in a high consistency horizontal mixer (pre-hidrolyzer) of 110L capacity where the hydrolysis of the wood pulp starts. After the pulp is enzymatically liquefied, the mixture is transferred to a 100L hydrolyzer to complete the cellulose to glucose conversion. The glucose is fermented to ethanol using a Saccharomyces cereviseae string in a 75L fermentor (Applikon, Netherlands) with sensors to precisely control temperature, pH, O2, and nutrients. Prehidrolyzer, hydrolyzer and fermentor are combined with a filter press to adjust the operation to a simultaneous saccharification and fermentation process or to a separate hydrolysis and fermentation process. Finally, distillation takes place in a packed bed distillation column and a 230L capacity reboiler. The operation of each stage of the process is batch. Additionally, all the complimentary equipment is in place for this pilot plant to successfully mimic a biorefinery. This equipment include centrifuge, filter press, disc refiner, precipitator, and utilities to supply the plant with medium pressure steam, hot water, cooling water, deionized water, compress air, and nitrogen. This work shows a pilot plant experience to obtain ethanol from using autohydrolysis pretreatment and simultaneous saccharification and fermentation with high solids loads and a comparison with the results obtained in bench scale.