Dissolution reaction kinetics and mass transfer during aqueous choline chloride pre-treatment of oak wood

Model-based process intensification of dilute acid pre-hydrolysis of oil palm empty fruit bunch biomass for pretreatment and furfural production

A novel process for simultaneous production of furfural and pretreatment of oil palm empty fruit bunch (EFB) by dilute acid pre-hydrolysis was developed based on non-isothermal kinetic modeling. Mass transfer analysis suggested that the internal diffusion could be neglected as diffusion time of sulfuric acid in EFB particles was significantly shorter than the pre-hydrolysis period, whereas the heating stage could not be neglected due to a significant part of xylan was solubilized at the stage. A strategy for increasing furfural yield was developed by intermittent discharging of steam, resulting in 71.4 % furfural yield. The pretreated solids showed good enzymatic digestibility. 136.3 g/L glucose corresponding to 81.6 % yield was obtained by high-solid loading hydrolysis. 95.4 g furfural and 212 g glucose could be obtained from 1 kg dry EFB. Therefore, non-isothermal effects on polysaccharide hydrolysis and pentose decomposition should be considered carefully for an efficient process design of EFB biorefining.

The Impact of the Deterioration on Wood by Chlorine: An Experimental Study

The use of disinfection and cleaning chemicals in several municipal facilities, such as swimming pools and drinking water treatment plants, causes the degradation of various types of wood, which leads to failures in equipment and the corresponding need for maintenance. This degradation creates added costs for municipalities, as well as the closure of certain facilities due to curative or preventive maintenance and, in many cases, public health issues, due to the water being contaminated with deteriorating products. Through a thorough study of the degradation effect on the products, more resistant materials can be found which are able to withstand these adversities and increase the lifespan of wood in regular contact with chemical agents. This is achievable by the determination of the cost-effectiveness of the substitute material to replace these components with alternative ones, with properties that better resist the deterioration effects promoted by aggressive environments. No studies have been found so far strictly focused on this matter. The objective of this study is to evaluate the degradation presented by two types of wood, beech and oak, which are exposed to the action of chlorine in municipal facilities. This degradation varies according to the chlorine content and the materials' time of contact with the chemical agent, allowing the selection of new materials which will provide an extended lifetime of the components, reducing maintenance drastically, as well as costs for the facilities and the risk to public health. The performed experimental tests have shown that the oak wood has the best results regarding chlorine degradation resistance.

Kinetics of Lignin Separation during the Atmospheric Fractionation of Bagasse with p-Toluenesulfonic Acid

As a green and efficient component separation technology, organic acid pretreatment has been widely studied in biomass refining. In particular, the efficient separation of lignin by p-toluenesulfonic acid (p-TsOH) pretreatment has been achieved. In this study, the mechanism of the atmospheric separation of bagasse lignin with p-TsOH was investigated. The separation kinetics of lignin was analyzed. A non-simple linear relationship was found between the separation yield of lignin and the concentration of p-TsOH, the temperature and the stirring speed. The shrinking nucleus model for the separation of lignin was established based on the introduction of mass transfer and diffusion factors. A general model of the total delignification rate was obtained. The results showed that the process of lignin separation occurred into two phases, i.e., a fast stage and a slow stage. The results provide a theoretical basis for the efficient separation of lignin by p-TsOH pretreatment.

Kinetics of Lignin Removal from Rice Husk Using Hydrogen Peroxide and Combined Hydrogen Peroxide–Aqueous Ammonia Pretreatments

The rice husk has the potential to be used for converting agricultural wastes into renewable energy. Therefore, this study aims to improve the hydrolysis of rice husk through Hydrogen Peroxide (HP) and Combined Hydrogen Peroxide–Aqueous Ammonia (CHPA) pretreatments. The removal of lignin from rice husks was determined using SEM–EDS examination of the samples. At a specific concentration of H2O2, (CHPA) pretreatment eliminated a significantly larger amount of lignin from biomass. The percentage of lignin removal of HP varied from 48.25 to 66.50, while CHPA ranged from 72.22 to 85.73. Hence, the use of batch kinetics of lignin removal of both pretreatments is recommended, where the kinetic parameters are determined by fitting the experimental data. Based on the results, the activation energies for HP and CHPA pretreatments were 9.96 and 7.44 kJ/mol, which showed that the24 model is appropriate for the experimental data. The increase in temperatures also led to a higher pretreatment value, indicating their positive correlation. Meanwhile, CHPA pretreatment was subjected to enzymatic hydrolysis of 6% enzyme loading for the production of 6.58 g glucose/L at 25 h.