Chemical Engineering

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Shiv Nadar University

Food waste generation is a worldwide phenomenon and disposing off it in an environmentally benign way has been a challenge. Thermochemical processes have the potential for not only processing mixed food waste effectively from an environmental point of view but also producing bioenergy in all three forms: solid (biochar), liquid (bio-oil) and gas (syngas). In this study, two thermochemical processes – fast pyrolysis and steam gasification – aimed for producing syngas as main product were carried out at three different temperatures: 600°C, 700°C and 800°C, and resulting syngas was characterised and compared for syngas yield, syngas composition, hydrogen yield and high heating value (HHV). The steam flow rate (SFR) was maintained at 0.625 mL min−1 for all gasification experiments. The syngas yield obtained from steam gasification was higher (1.2 m3 kg−1) than the syngas yield from fast pyrolysis (0.81 m3 kg−1). In addition, the hydrogen fraction was much higher in syngas from steam gasification (63.58%) than that from fast pyrolysis (45.03%). Furthermore, carbon conversion efficiency (CCE) and apparent thermal efficiency (ATE) were determined to compare the performance of these two processes. CCE was higher (63.6%) for steam gasification than that for pyrolysis (52.3%) which suggested that steam gasification was much more effective than fast pyrolysis to produce syngas of higher quality. © The Author(s) 2022.

World University root node

(SoE) School of Engineering

Waste Management and Research

Syngas production from fast pyrolysis and steam gasification of mixed food waste

This study introduced an integrated two-stage process (ITP) for treating the mixed food waste (MFW) and producing syngas with higher hydrogen fraction where in-situ steam gasification was conducted after fast pyrolysis at the same temperature. Characteristics of syngas (syngas yield, composition, H2 yield, and high heating value (HHV)) from the proposed approach was first compared with that from conventional overlapping process (COP) of steam gasification process at the same temperature of 700°C and then with that from ITP at a higher temperature of 850°C. Syngas yield from ITP at 700°C (0.91 m3/kg) was almost the same as the syngas yield from COP at 700°C (0.85 m3/kg); however, the hydrogen and CO fraction were much higher (H2: gasification part~ 63%, average ~ 57.8%; CO: gasification part ~ 25%, average ~ 24%) than that from COP at 700°C (H2: 52%, CO: 19%). The hydrogen fraction in syngas further increased to 68% (from the gasification part) on increasing the ITP temperature to 850. Moreover, the syngas yield increased significantly (1.51 m3/kg) at the higher temperature of 850°. Finally, change in HHV values and corresponding changes in cold gas efficiency (CGE) were also presented to evaluate the process performance. © 2022 Taylor & Francis Group, LLC.

Energy Sources, Part A: Recovery, Utilization and Environmental Effects

Hydrogen rich syngas production from food waste via an integrated two-stage process of in-situ steam gasification after fast pyrolysis

Density functional theory and molecular dynamic simulations were used to understand the microscopic-level interactions of pectin-based thin films with moisture (H2O), carbon dioxide (CO2), and oxygen (O2). Galacturonic acid (GA), which forms ~65% of the smooth region of pectin polymer, was chosen for the current study. The electrostatic potential and Fukui function maps indicate that oxygen atoms of –OH groups of GA are the most reactive sites for electrophilic attack and hydrogen atoms on the carboxylic group (–COOH) are the reactive sites for nucleophilic attack. The GA molecule has shown strong interaction via hydrogen bonding with H2O (E= ~ 40 kJ/mol) followed by CO2 (E = ~ −13 kJ/mol). Nucleophilic O2 showed insignificant interaction with GA. Surface interaction, adsorption, and diffusion of sorbate molecules on the GA film followed the order of H2O &gt;CO2 &gt; O2. Molecular interaction studies provided atomistic insights into the weak moisture and high gas barrier properties of pectin films. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Journal of Molecular Modeling

Molecular Simulations to Understand the Moisture, Carbon Dioxide, and Oxygen Barrier Properties of Pectin Films

Atomistic level understanding of the interactions of thiophene and iso-octane with various organic solvents such as N-methylpyrrolidone (NMP), sulfolane, furfural, diethyleneglycol (DEG), 2-aminoethanol (ETA), tetraethyleneglycol (TEG), dimethylformamide (DMF) and cyrene to find an optimum solvent for selective extraction of thiophene, was presented by using DFT and MD simulations. As per the reactivity descriptors computed from Koopmans’ theorem based on quantum mechanics, for the eight solvents studied, furfural is most reactive followed by cyrene while sulfolane has the least reactivity. Based on the interaction energies (IE) of solute–solvent systems using DFT, cyrene presented strongest interaction with thiophene followed by TEG, furfural and DEG indicating that cyrene can show good thiophene removal capacity. The difference in the IE values of thiophene and isooctance was considered as a measure of possible sulphur selectivity over hydrocarbon. Among the eight solvents considered, furfural, DEG, TEG and cyrene observed to show good desulfurization selectivity. The favourable positions on solvent molecules for potential interactions with thiophene and isooctane were identified using orbitals, electrostatic potential maps, fukui function maps for electrophilic and nucleophilic attack, match well with the trends in IE values and RDFs from MD simulation. The solute–solvent concentration profiles and radial distribution functions computed using MD simulations evidently show that furfural and cyrene show better capacity and selectivity for Thiophene which are in correspondence with DFT results. The detailed analysis using QM and MM methods, concludes that cyrene, furfural and TEG are the optimum organic solvents for thiophene removal from gasoline using extractive desulfurization method (EDS). © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Environmental Science and Engineering

Screening of Organic Solvents for Separation of Thiophene and Iso-octane: Density Functional Theory and Molecular Dynamic Simulations

This study presents the utilization of paper mill sludge (PMS) as biomass for producing hydrogen from steam gasification. PMS is a wet waste and its utilization for hydrogen production would give a new direction to its management. In this work, the performance of PMS during steam gasification was studied by varying the steam flow rate (SFR) and by determining the various characteristics of product gas such as syngas yield, syngas composition, and its high heating value (HHV). The SFR was varied from 0.25 mL/min to 1.0 mL/min depending upon the steam to biomass ratio. The performance parameter, cold gas efficiency (CGE) was also determined to evaluate the performance of PMS during steam gasification and the highest CGE was found to be around 96% at optimal SFR. The optimal SFR was found to be 0.75 mL/min and the syngas characteristics at optimal SFR were found to be 1.4 m3/Kg (syngas yield), 58% (hydrogen fraction in syngas), and 11.92 MJ/m3 (HHV). The feasibility of the PMS management and its utilization using steam gasification methods can further be increased by using renewable sources of energy for heating the gasifier. © 2022 Informa UK Limited, trading as Taylor & Francis Group.

Biofuels

Utilization of paper mill sludge as a sustainable source of hydrogen production

In the present study, the composition of bio-oil was determined using various analysis techniques such as H-NMR, 13 C-NMR, DEPT 90 & 135, and GC-MS. The bio-oil was produced from torrefaction of mixed food waste at 300 °C with heating rate of 10 °C/min. The novelty in this study lies in two facts; (i) NMR has been used as a qualitative method in contrary to it being used a quantitative method in previous works on bio-oil from other biomass and the compounds identified via GC-MS were cross checked via NMR Spectra of the compounds that were present in large quantity in bio-oil sample (> 3%); (2) bio-oil from mixed food waste (MFW) as no study was there to determine the detailed composition of bio-oil from MFW. Characteristics of MFW is quite different from typical biomass as it has additional compounds such as starch, protein, and lipids and found to be generating bio-oil of different composition. © 2022 Informa UK Limited, trading as Taylor & Francis Group.

Compositional study of bio-oil obtained from torrefaction of mixed food waste using H-NMR, 13C-NMR, DEPT 90 &amp; 135, and GC-MS

I&EC Research

<p>Effect of Inlet Contactors of Splitting Distributors for Parallel Microchannels</p>

In this work, food waste was treated using a novel method of in situ gasification after pyrolysis (IGP) at the same temperature of 700 °C. This was done with the expectation that IGP would result in a higher hydrogen fraction in syngas as opposed to hydrogen fraction from a more conventional approach of overlapping pyrolysis and gasification (OGP). Firstly, both IGP and OGP were carried out at the same steam flow rate (SFR) of 0.625 mL/min and then only IGP was carried out by changing the flow rate from 0.625 to 0.375 mL/min. Comparative data obtained from OGP and IGP was presented for syngas characteristics (syngas yield, syngas composition, hydrogen yield, high heating value (HHV)). The syngas yield from OGP and IGP at the same flow rate of 0.625 mL/min was found to be 1.31 Nm3/kg and 1.48 Nm3/kg, respectively. The hydrogen fraction in syngas from OGP was found to be 54.5%, which increased significantly to 66.7% in syngas from the gasification part of IGP. Consecutively, HHV increased with an increase in hydrogen fraction in syngas from 12.1 to 17.4 MJ/kg. Additionally, the syngas yield obtained from IGP did not change much on changing the SFR to 0.375 mL/min; however, the hydrogen fraction changed to a lower value of 61.04%. Furthermore, performance parameters such as carbon conversion efficiency (CCE) and cold gas efficiency (CGE) are also presented to evaluate the performance of proposed method. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Biomass Conversion and Biorefinery

Food waste treatment using in situ gasification after pyrolysis to produce hydrogen-rich syngas

Excess Al3+ ions are considered toxic to living organisms. Keeping the harmful effects of excess Al3+ metal ions in mind, a new Schiff base = functionalized silatrane as a potential chemo-sensor for the recognition of aluminium metal ions with high selectivity and specificity has been designed and well characterized using various characterization techniques such as IR, 1H NMR, 13C NMR, TGA, and mass spectroscopy. The chemo-sensing properties were studied using ultraviolet and fluorescence spectroscopy. The absorption spectrum of the synthesized receptor was changed only by the addition of Al3+ ions, while other ions showed negligible changes. The 1 : 1 stoichiometric ratio of the chemo-sensor 4b with Al3+ was confirmed by Job's plot and linearity in the B-H plot. The limit of detection observed for Al3+ ions was 2.273 × 10-7 M and 9.8 × 10-9 M from ultraviolet and fluorescence spectroscopy, respectively. The binding constant from the B-H plot and the Stern-Volmer quenching constant were found to be 0.2279 × 106 M-1 and 2.7 × 106 M-1, respectively. These results explain the potential chemo-selectivity of the receptor 4b towards Al3+ metal ions, which may be useful for biological and industrial purposes. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

New Journal of Chemistry

Schiff base-functionalized silatrane-based receptor as a potential chemo-sensor for the detection of Al3+ions

The present article describes the synthesis of Schiff base-acetylene functionalized organosilatranes (6a–6e) and their characterization by 1H and 13C NMR spectroscopy and ESI-QTOF mass spectrometry. The UV–visible study of the organosilatrane 6a unveiled their high selectivity towards the recognition of Zn2+ and Co2+ ions without exhibiting any significant interference from other competitive metal ions. The calculated value of association constant with 6a for Zn2+ and Co2+ ions was 0.11 × 106 M−1 and 0.24 × 106 M−1 and the limit of detection was 0.28 × 10−6 M and 0.82 × 10−6 M respectively. Furthermore, DFT calculations were performed to get an insight into the interacting behaviour of sensor 6a towards Zn2+ and Co2+ ions. © 2021

Inorganica Chimica Acta

Synthesis, characterization and UV–visible study of schiff base-acetylene functionalized organosilatrane receptor for the dual detection of Zn2+ and Co2+ ions