Liquid hot water pretreatment is considered to be a promising method for increaing biomass digestibility due to the moderate operational conditions without chemical additionA necessary step towards the scalability of this pretreatment process is performing pilot plant triaUpscaling was evaluated with a scaling factor of 500, by using 50 mL in the laboratory and 25 L in pilot plant batch reactor. Pretreatment times were varied from 30 to 240 min, and temperatures usewere 180–188◦ C, while applying similar heating profiles at both scales. The initial mass fraction poplar wood chips ranged from 10% to 16%. Liquid hot water pretreatment at laboratory and pilscale led to analogous results. The acetic acid analysis of the liquid and solid fractions obtained aftpretreatment indicated that complete deacetylation of poplar biomass can be achieved.@en

Pretreatment of lignocellulosic biomass is required for many biorefinery processes. Previous studies have described hydrolysis of hemicelluloses by using liquid hot water (LHW) pretreatment. We evaluated the effect of carbonic acid originating from pressurized carbon dioxide during LHW pretreatment of poplar. The conditions applied covered temperatures from 120 to 200 °C, pretreatment times from 5 to 240 min and pressures from 1.0 to 2.2 MPa CO2 or N2. The pressure and the type of gas (CO2 or N2) did not have an effect on production of acetic acid, which functioned as a marker of progress of biomass hydrolysis. Results suggested that the presence of carbonic acid in the process does not significantly contribute to acidification. Deacetylation of lignocellulosic biomass can be achieved by LHW pretreatment irrespective of pressure and of gas type used, at the conditions tested.@en

The use of renewable resources is nowadays a well-established practice and a general policy to address the fossil fuel depletion, as well as the continuous increase in greenhouse gas emissions. Several approaches have been adopted, with a growing trend toward developing new technologies that target efficiency, sustainability and feasibility. Because it closes the carbon cycle, biomass has a significant potential as renewable source, and not exclusively for the production of energy. Thus, similar to the traditional refinery, the fractionation and conversion of sources to generate, separate and purify different products is also applicable to biomass. Hence, the concept of biorefinery enables the use of renewable feedstocks to obtain bio-based fuels, chemicals and materials in a greener and eco-friendlier manner. Moreover, lignocellulosic biomass (LCB) used as second generation feedstock, encompasses plenty opportunities due to features such as availability, price and versatility....@en