Chemical engineer, São Paulo University; Master’s degree in Process Control and Simulation, São Paulo University; Doctoral degree in Sustainable Energy Systems, Lappeenranta University of Technology, Finland. Twelve years of experience in the Pulp and Paper industry and working with biorefining technologies since 2008. Currently responsible for R&D projects for Valmet in South America.
Biomass pre-hydrolysis: a key step to sustainable biofuels
Producing first generation ethanol from sugarcane juice is quite straightforward because it contains simple sugars that yeast can easily digest. On the other hand, the production of cellulosic ethanol requires additional steps to handle more complex carbohydrates prior to the fermentation process. A route that has been mostly explored so far consists of: pretreatment (pre-hydrolysis) of biomass waste, enzymatic hydrolysis, followed by fermentation of the resulting sugars.
Based on the knowledge gained in the pulp and paper industry, Valmet has been supplying industrial scale equipment for biomass pretreatment. The main objective is to make the cellulose more accessible to enzymes and to dissolve hemicellulose sugars, mainly C5 sugars, as oligo or monosaccharides. One important feature of a well-designed pretreatment is the capability in achieving reliable and uniform biomass feeding flow at high pressure conditions.
Valmet pre-treatment process can be performed with steam, hot water or with addition of dilute acid. The reactor temperature is usually in the range of 170-220°C, meaning that the system can be flexible in terms of both raw material and process. Feeding operation at high pressure can lead to frequent failures, especially when raw-materials such as bagasse and straw are used. One example is the frictional effect of abrasive materials present in biomass that can lead to equipment erosion. Technology suppliers such as Valmet are continuously working to minimize the negative impacts caused by these impurities. The objective of this presentation is to show how Valmet has been contributing to develop reliable pre-hydrolysis systems, which includes e.g. biomass pre-compression to accomplish a steady feed into the reactor while improving safety and availability.