This thesis mainly focuses on the extraction of biochemicals such as acetic acid, acetol and furfural due to its large composition in bio-oil. The first step in extracting chemicals from bio-oil is an extraction-based separation process that uses water as a solvent.
List of Tables
Natural charges according to Natural Bond Order (NBO) Method for Trans trans. Tt) conformer of glycolaldehyde and water complexes. 253 A.17.MP2 Energy (kJ/mol) of Furanone and water complexes with Respect to furanone-water complexes performed at the MP2/6-311++G** Level. furanone-water complexes performed at the MP2/6-311++G** Level. furanone-water complexes performed at the MP2/6-311++G** Level.
Nomenclature
Introduction
At the same time, excessive consumption of fossil fuels has increased the emission of greenhouse gases, thereby posing a serious threat to the environment. These energy sources should be renewable, CO2-neutral and should have the potential to replace fossil fuels.
Biomass conversion processes
It involves the rapid oxidation of fuel to obtain energy in the form of heat, which can be used for process heating or steam production. Pyrolysis is known for the conversion of solid biomass into liquid, gaseous and solid fractions by heating in the absence of air.
Pyrolysis
The pyrolysis oil can be used in subsequent processing for heat/power generation, as biofuel and for the production of chemicals. The main product, bio-oil, is obtained in yields of up to 75 wt% on a dry feed basis, together with by-product charcoal and gas that can be used within the process, thus creating no waste streams [Mohan et al. al. , 2006, Bridgewater, 2012, Crocker, 2011].
Bio-oil
For effective use, bio-oil must be separated and concentrated into compounds of similar polarities. To achieve these conditions, solvent fractionation and de-oxygenation are practiced to upgrade the bio-oil mixture [Mohan et al., 2006, Bridgwater, 2012].
Upgradation of bio-oil
- Catalytic upgrading of Bio-oil
- Solvent Fractionation of Bio-oil
Albuquerque et al., 2015] have reported the catalytic synthesis route for the production of lactic acid from aqueous hydroxyacetone solutions at atmospheric pressure. It is further used for the synthesis of tetrahydrofurfuryl alcohol and pharmaceuticals [Mariscal et al., 2016].
Objective of the Thesis
PC-SAFT EoS is used to predict phase equilibria of biochemical systems studied in Chapter 3. In Chapter 6, particle-based Monte Carlo (MC) simulation is used to study liquid-liquid phase equilibria.
R EFERENCES
Introduction
Ma et al., 2013] investigated the hydrogen bond interactions in HXeCCH · · · H2O and HXeCCH · · · HF complexes by Ab initio calculations. Then, the calculated interaction energies were considered as a measure of the solubility of the bio-oil molecules in water.
Theory and Methods
- Energy Decomposition Analysis
- Computational Details
The geometry optimization of all complexes was performed using the Gaussian 03 program [Frisch et al., 2004]. To better understand the interactions, the natural charges for the various complexes were calculated with the natural bond orbital (NBO) method available in Gaussian 03 software [Glendening et al.,.
Results and Discussion
- Glycolaldehyde and water complex
- Furfural-water, Acetic acid-water and Furanone-water complexes
- Inferences from interaction energies and its relation with distribution coefficients
Two different hydrogen peaks correspond to the optimized geometry (Figure 2.1) and second order perturbative energyEi→j(2) values. Therefore, based on total energy and interaction energy, we can conclude that complex Cc-1 (Figure 2.1) is more stable. The interaction energies between acetic acid-water, glycolaldehyde-water, furanone-water and furfural-water are tabulated for the most stable complexes in Table 2.2 and shown in Figure 2.17.
When the individual energy terms are compared, they follow the same trend due to total interaction energy as shown in Figure 2.17, i.e. (Acetic acid: ∆EES;.
Conclusions
Ir-induced conformer interconversion processes of glycolaldehyde in low-temperature matrices, and ab initio calculations of the energy and vibrational frequencies of the conformers. On the connection between the supermolecular Møller-Plesset treatment of the interaction energy and the perturbation theory of intermolecular forces. Photochemistry and vibrational spectroscopy of the trans and cis conformers of acetic acid in solid art.
Competition between n [arrow right] [small pi]ar* interactions and conventional hydrogen bonds (n-h[three dots, center]n): an ab initio study of complexes of 7-azaindole and fluorosubstituted pyridines.
Introduction
Chapter-3 has been extracted from an aqueous phase derived from bio-oil [Mahfud et al., 2008]. Similarly, extraction of bio-oil with water followed by CH2Cl2/CHCl3 effectively separated sugars and sugar derivatives from aromatics. Further acid treatment in methanol converted the sugar to levulinic acid/ester and sugar derivative to fuel derivatives [Hu et al., 2012].
In summary, the organic solvents extracted a higher fraction of chemicals from bio-oil in combined mode than in sequential extraction.
Experiments
- Chemicals and Materials
- Density Measurement
- Liquid-Liquid Equilibria Experiments
- Composition Analysis
Peaks at 5.0 ppm and 1.16 ppm were used for quantification of acetol and ethyl acetate, respectively. The peak at 0.85 ppm due to three H atoms was used for the quantification of n-propyl acetate and n-butyl acetate. Peak at 8.0 ppm due to single H atom was used for quantification of furfural in both phases.
Peak at 9.0 ppm due to a single H atom was used for the quantification of [EMIM][Tf2N] and [BMIM][Tf2N].
Results and Discussions
- Regeneration of Ionic Liquids
The experimental LLE ternary diagram for these systems is shown in Figures 3.6-3.11 and Figure 3.12 shows the com-. Mole fraction (%) of solvent in raffinate for ethyl acetate, n-propyl acetate, n-butyl acetate, chloroform, [EMIM][Tf2N]. Finally, the performance of [BMIM][Tf2N] was also compared with other solvents (ethyl acetate, propyl acetate, 1-butanol, tert-pentanol) as reported in literature in terms of distribution coefficient and selectivity [de Almeida et al., 2012, Mannisto et al., 2016] and shown in Figure 3.14.
Overall, [BMIM][Tf2N] and propyl acetate are potential solvents for the extraction of furfural from aqueous solution.
Conclusions
Liquid-liquid equilibria in the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorone (3,5,5-trimethyl-2-cyclohexen-1-one). Production of value-adding chemicals from bio-oil via acid catalysis combined with liquid-liquid extraction. Recovery of acetic acid from an aqueous pyrolysis oil phase by reactive extraction with tri-n-octylamine.
Liquid-liquid equilibria for acetic acid + water + amyl acetate and acetic acid + water + 2-methylethyl.
Introduction
Zhang et al., 2011a] have further applied the IDE algorithm for parameter estimation to VLE modeling problems. Merzougui et al ., 2012 ] to calculate the interaction parameters of the NRTL model for twenty liquid–liquid ternary systems. Kabouche et al., 2012] have used SA, GA, Nelder-Mead Simplex (NMS), SA-NMS (hybrid), and GA-NMS (hybrid) to estimate the interaction parameters of the NRTL and UNIQUAC models for LLE systems.
Bhargava et al., 2013] used the CS algorithm to solve phase stability, phase balance, and reactive phase balance problems.
Theory and Calculation
- Cuckoo Search (CS)
- UNIQUAC Model and NRTL Model
- Liquid-Liquid Equilibria Modeling
The initial population of the nests is randomly generated between the lower bound and upper bound. The maximum number of iterations or tolerance criterion can be used as termination criterion of the algorithm. The pseudo-code and the flowchart of the CS algorithm are shown in Figure 4.1 and Figure 4.2, respectively.
The composition of the extract and raffinate phases is calculated using a flash algorithm (Figure 4.3) as described by the modified Rashford-Rice Algorithm [Seader, 2006].
Results and Discussions
- Effect of Bounds
- Maximum Number of Iterations and Population size
- Comparison with Reported Data
- Bio-Chemicals based ternary systems
Chapter-4 Table 4.3.: Abbreviation and full name of ionic liquids used in this work along with UNIQUAC structure of volume and surface area. After comparing with the above system, CS has been applied to other ternary systems. Vatani et al., 2012] performed liquid–liquid equilibrium calculation for 20 different IL-based ternary systems from the NRTL model with binary interaction parameters calculated using the Genetic Algorithm (GA).
Chapter-4 has been carried out and the lowest RMSD along with the corresponding interaction parameters was selected as the final result and reported in Table 4.13 and Table 4.14.
Conclusions
Chapter 4 Table 4.9: UNIQUAC binary interaction parameters and RMSD values for ionic liquid-based ternary systems. Chapter 4 Table 4.10: UNIQUAC binary interaction parameters and RMSD values for organic solvent-based ternary systems. Chapter 4 Table 4.11: NRTL binary interaction parameters and RMSD values for ionic liquid-based ternary systems.
Chapter-4 Table 4.16.: UNIQUAC binary interaction parameters and RMSD values for ternary systems based on bio-oil chemicals.
Introduction
The expansion in mixing requires mixing rules for the two EoS parameters, the energy parameter (a) and the co-volume one (b). The reason for the not so good prediction for the polar and associated components is inherent in the cubic EoS. Cubic EoS considers only dispersive intermolecular interactions and does not take into account specific intermolecular interactions such as hydrogen bonds which are present in polar and associative components.
In the context of the thesis we will focus on the latter, i.e. PC-SAFT EoS, since the mixtures have.
PC-SAFT EoS
Chapter-5 where ˜ares is the remaining Helmholtz free energy in the system (˜ares =a˜total - ˜aideal) andga˜ = A/N kT. In Equation 6.1, the sum of the first two terms is the hard sphere chain reference system, which accounts for molecular repulsion and chain association, while the last two terms are the perturbation, which accounts for molecular attraction and for association due to specific interactions, respectively. Hard-chain contribution: The Helmholtz energy of the hard-chain reference term is given as.
Chapter-5 In terms of compressibility factor Z, EoS is given as the sum of the ideal gas contribution (Zid = 1), the hard chain contribution (Zhc), the dispersive (attractive) contribution (Zdisp) and the contribution due to associating interactions (Zassoc).
Results and Discussions
- Parameterization of PC-SAFT EoS
AARD(%) = 100 n pts
PC-SAFT modeling of ternary liquid-liquid systems
RMSD =
The experimentally observed phase behavior for the ternary system was well predicted by PC-SAFT. Based on this, modified PC-SAFT parameters for water and acetol are reported in Table 5.8. Based on these assumptions, LLE data were predicted by PC-SAFT and are reported in Table 5.9.
More interestingly, with these parameters, PC-SAFT predicted VLE agrees well with that of COSMO-SAC prediction (Figure 5.15).
