Araceli García

Ultrasound-assisted fractionation of the lignocellulosic material

In the present work the effectiveness of different lignocellulosic biomass fractionation processes based on ultrasounds technology was evaluated. Organosolv (acetic acid 60% v/v), alkaline (sodium hydroxide 7.5% w/w) and autohydrolysis treatments were applied at low temperature and the fractionation effectiveness was measured at different sonication conditions of the raw material. The obtained solid fractions were characterized using TAPPI standard methods, and the liquid fractions main components were quantified with the purpose of studying the effect that the treatment conditions had on the obtained by-products quality. Therefore, obtained lignin samples were characterized by ATR-IR spectroscopy and their thermal behaviour by TGA technique. The results showed that ultrasounds application improved the yield and selectivity of the studied processes and that the obtained lignin did not suffer significant modifications in its physicochemical properties.

Evaluation of the effect of ultrasound on organosolv black liquor from olive tree pruning residues

Ultrasonic treatments (0, 15, 30, 60 and 120 min) were applied to black liquor resulting from organosolv fractionation of olive tree pruning residues (ethanol/water 60/40 v/v, 180 °C, 60 min) in order to determine their effect on black liquor components. HPLC analyses of ultrasound-treated liquid fractions demonstrated that ultrasonic irradiation promoted up to 20% degradation of monosaccharides for 15 min of sonication and an increase of monomeric sugars from 3% to 16% due lignin-carbohydrate complex rupture. The quality and purity of the lignin precipitated from sonicated liquors by adding acidified water were assessed. Attenuated-total reflectance infrared spectroscopy (ATR-IR), gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) confirmed that main lignin structure did not change due sonication, and thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and chemical composition and antioxidant behavior showed purification of lignin samples. These results established sonication as a suitable intensification technology in biorefinery processes.

Simulation of tagasaste pulping using soda-anthraquinone.

In this work, published experimental result data of the pulping of tagasaste (Chamaecytisus proliferus L.F.) with soda and anthraquinone (AQ) have been used to develop a model using a neural network. The paper presents the development of a model with a neural network to predict the effects that the operational variables of the pulping reactor (temperature, soda concentration, AQ concentration, time and liquid/solid ratio) have on the properties of the paper sheets of the obtained pulp (brightness, traction index, burst index and tear index). Using a factorial experimental design, the results obtained with the neural network model are compared with those obtained from a polynomial model. The neural network model shows a higher prediction precision that the polynomial model.

Assessment of biorefinery process intensification by ultrasound technology.

In the present work, on the basis of literature data, correlations for ultrasound-assisted dissolution of lignin and hemicelluloses from lignocellulosic raw material were defined in Aspen Plus® as function of applied power and duration of the ultrasound treatment. The dissolution yield of these biomass components was represented against the applied acoustic energy, taking into account the volume of solvent–solid treated in each case, making possible the calculation of ultrasonic power consumption in a simulated biorefinery pretreatment process. The proposed ultrasound-assisted process was techno-economically evaluated in terms of process yield and utility requirements. Furthermore, energy and exergy analyses were performed in order to assess the profitability of the simulated ultrasound-assisted biomass fractionation processes.

Energy Optimization of a Kraft Pulp Mill

Abstract New regulations, economical and environmental requirements urge industrial companies to continuously improve the efficiency of their production technologies. The application of process integration tools for process retrofit is a must whenever energy or raw material intensive processes are considered. Since pulp and paper processes use a large amount of energy and water, the application of process integration techniques in this area is essential and can contribute to the protection of the environment to a great extent. CadSim Plus simulation software has been used to simulate several sections of a kraft pulp mill. Based on the process flow sheet and the developed simulation, pinch analysis was undertaken using the software Aspen HX-Net 2006. Potential of energy savings has been identified and the feasibility of the associated heat exchangers network (HEN) modification has been evaluated by the process simulation. The combination of both computer tools, has allowed to carry out the study of energy optimization of the process, maintaining the conditions of operation and evaluating the feasibility of the possible changes in the design of the heat exchangers network that allow minimizing the energy consumption.

Energy and Economic Assessment of Soda and Organosolv Biorefinery Processes

The paper industry is facing the necessity of improving process efficiency, especially in terms of energy and raw materials consumption. In most of the cases, the production of pulp and paper generates an energy surplus that is often not conveniently used. The actual trend is to convert traditional pulp and paper processes in biorefineries where all components of lignocellulosic materials can be converted in added value products such as bioethanol, lignin, cellulose whiskers and other chemicals than can replace the common petroleum based products. In the present work, the energetic and economical efficiencies of two biorefinery processes were studied using the simulation software Aspen Plus. Soda and organosolv processes were used for raw material delignification. The simulation design and treatment sequences (reaction, solid fraction washing, products recovery and liquid fraction processing) are similar for both processes. Mass and energy balances were established and the processes were compared in terms of yield, solvents/reactants recovery and energy consumption based on the same amount of processed raw material. In this way, the development of rigorous simulations allowed to determine the economical feasibility of both biorefinery models, and to establish the optimal operation conditions for both processes.

Simulation basis for a techno-economic evaluation of chitin nanomaterials production process using Aspen Plus® software

Process simulation is a useful tool that has been widely used to analyze, design and optimize energy balances in chemical technologies including those related to biomass processing, biorefinery processes and chemical engineering. The presented data set serves as basis for the simulation of chitin purification, nanofibers and nanocrystals production processes, considering laboratory experimental procedures described in previous experimental articles.