Conversion Routes Research Articles

In-situ topochemical nitridation derivative MoO2–Mo2N binary nanobelts as multifunctional interlayer for fast-kinetic Li-Sulfur batteries

Li-Sulfur batteries (LSBs) have a wide application foreground for its high energy density and low-cost, however, the shuttle effect, volume fluctuation and irregular Li2S deposition on the cathode side often result in severe capacity decaying during its cycles. It is necessary to design and optimize the conversion route from sulfur (S8) to lithium sulfide (Li2S) to improve the reversibility of Li–S battery. Herein, novel MoO2–Mo2N binary nanobelts synthesized from α-MoO3 through an in situ topochemical nitridation process were employed as the highly efficient interlayer material for LSBs, which not only acted as a physical barrier to alleviate the shuttle effect but also regulated the conversion of lithium polysulfides (LiPSs) across the interface and optimized the nucleation of solid Li2S during cycling. Combining the polarity of MoO2 with the conductivity of Mo2N, such hybrid structure exhibited excellent cycling stability with a very low capacity decay of 0.028% per cycle up to 500 cycles at 1C. Even under the high areal sulfur loadings of 3.1 and 4 mg cm−2, the high discharge capacity and excellent capacity retention ratio can also be obtained. The concept of in-situ binary heterogeneous interfaces construction might also be used in the design and preparation of other electronic devices.

Computer modelling of automobile engine performance as the source of implications for automobile technology management

The need for finding the replacement for fossil fuels causes several technical and technological problems in the engine construction as well as the fuel production and its standardisation. This particularly concerns biofuels. The variety of biological resources and possible conversion routes leads to the multiplication of fuel properties. The regional dependence of biomass resources might cause interregional incompatibility of fuels, which should be avoided. Our previous studies have shown that computer modelling is capable of providing information on the dependence of engine performance upon the type of the fuel used, also under conditions of simulation of road tests. Based on computer simulations of the given engine cycle, the impact of the use of biofuels on carbon dioxide emissions from a diesel and gasoline engine was analysed. The tested fuels were: gasoline 95, diesel, ethanol, DME dimethyl ether, and FAME fatty acid methyl esters. The differences in CO2 emissions of the tested fuels were large (up to 17%), but none of the analysed fuels exceeded the maximum emission limits allowed by legal regulations. The results of such simulations might be used for planning the development of various types of engines -possibly adjustable to fuels of various origin, as well as for planning the fuel composition assuring the best performance in a wide spectrum of engine constructions.

Pyrolysis study of hydrothermal carbonization-treated digested sewage sludge using a Py-GC/MS and a bench-scale pyrolyzer

The disposal of digested sewage sludge is becoming a global problem. Hydrothermal carbonization (HTC) combined with the pyrolysis of digested sewage sludge was investigated by using a new conversion route for the exploitation of sewage sludge in energy applications. The thermochemical properties of the material were investigated by using HTC pre-treatments, thermogravimetric analyses, pyrolysis tests in Py-GC/MS and a bench-scale fixed bed reactor at temperatures of 450, 550, and 650 °C. It was found that the thermal decomposition of the hydrothermally treated digested sewage sludge takes place in a two-stage reaction. After pyrolysis, the ash in the sample was oxidized in the O2 atmosphere at 900 °C. Therefore, a new characterization method for determination of the non-oxdized ash content and fixed carbon content was proposed. The result from Py-GC/MS shows that the abundance of aromatic hydrocarbons in pyrolytic vapors present a positive correlation with increased temperature. In the bench-scale experiments, the highest HHV of the organic fraction was obtained at 650 °C as 38.46 MJ/kg.

Sewage sludge conversion via hydrothermal liquefaction (HTL) – A preliminary study

Sewage sludge is regarded as a residue produced from municipal waste water treatment system. This waste is often used in low-value applications such as composting and incineration or disposed in landfills. Such practices posed many potential environmental hazards due to high levels of pollutants in the sludge. Sewage sludge is also a potential energy and currently received renewed attention for potential recovery of bio-oils and biochemicals through thermochemical conversion route. Hydrothermal liquefaction is a promising green method for conversion of sewage sludge. Hydrothermal liquefaction of sewage sludge were investigated at different temperatures (250°C, 300°C, 350°C and 400°C) and 1 hour reaction time. Experiments were carried out in a 10 ml stainless steel bomb reactor. The initial calorific value of sewage sludge was 12.36 MJ/kg. It was found that significant bio-oil yield of 52.23% and 48.25% were obtained at 350°C and 400°C respectively. Overall, the bio-oil yield increases with temperature up to critical temperature of water. It was clear that synergetic effect on the yield of liquid and solid were observed due to extended biomass fragmentations and depolymerization when reaction temperature was raised.The bio-oils produced from liquefaction of sewage sludge at 350°C contained an abundant number of ester based compounds, highlighting its potential as biofuel.

Agro-residues and weed biomass as a source bioenergy: Implications for sustainable management and valorization of low-value biowastes

Biomass resources are gaining increasing importance world over due to their ease of conversion to various energy product in the face of depleting fossil fuel store and increasing environmental concerns over their use. The present work elucidates different physico-chemical properties of three biomasses, paddy straw (PS)- an agricultural residue, spent paddy straw obtained after mushroom cultivation (SS), and a noxious weed (Parthenium hysterophorus; PR) to understand their properties and to explore the feasibility of using them as feedstocks in different biomass to bioenergy conversion routes. In addition to physico-chemical analysis, biochemical analysis of these biomasses along with XRD, thermogravimetric analysis, FTIR and SEM analysis have been carried out. Present study suggests that PS is a better choice as feedstock compared to both PR and SS. The calorific value to ash content ratio is more in PS (1.13) as compared to PR (1.06) and SS (0.84). Thus, it may be inferred that the biomasses in question are at par with commonly used bio-energy feedstocks like sugarcane bagasse and corn cob. ©2019. CBIORE-IJRED. All rights reserved

A carbon footprint assessment of multi‐output biorefineries with international biomass supply: a case study for the Netherlands

AbstractThe efficient use of lignocellulosic biomass for the production of advanced fuels and bio‐based materials has become increasingly relevant. In the EU, regulatory developments are stimulating the mobilization and production of bio‐based chemicals / materials and biofuels from lignocellulosic biomass. We used an attributional life‐cycle assessment approach based on region‐specific characteristics to determine the greenhouse gas emissions (GHG) performance of different supply‐chain configurations with internationally sourced lignocellulosic biomass (stem wood, forest residues, sawmill residues, and sugarcane bagasse) from the USA, the Baltic States (BS), and Brazil (BR) for the simultaneous production of lactide and ethanol in a biorefinery located in the Netherlands (NL). The results are compared with a biorefinery that uses locally cultivated sugar beets. We also compared GHG emissions savings from the supply‐chain configurations with the minimum GHG saving requirements in the revised Renewable Energy Directive (RED II) and relevant fossil‐based counterparts for bio‐based materials. The GHG emissions ‘from cradle to factory gate’ vary between 692 g CO2eq/kglactide (sawmill residues pellets from the BS) and 1002 g CO2eq/kglactide (sawmill chips from the USA) for lactide and between 15 g CO2eq/MJethanol (sawmill residues pellets from the BS) and 28 g CO2eq/MJethanol (bagasse pellets from BR) for ethanol. Upstream GHG emissions from the conversion routes have a relatively small impact compared with biomass conversion to lactide and ethanol. The use of woody biomass yields better GHG emissions performance for the conversion system than sugarcane bagasse or sugar beets as result of the higher lignin content that is used to generate electricity and heat internally for the system. Only the sugar beet from the NL production route is able to comply with RED II GHG savings criteria (65% by 2021). The GHG savings from polylactide acid (a derivate of lactic acid) are high and vary depending on choice of fossil‐based counterpart, with the highest savings reported when compared to polystyrene (PS). These high savings are mostly attributed to the negative emission credit from the embedded carbon in the materials. Several improvement options along the conversion routes were explored. Efficient feedstock supply chains (including pelletization and large ocean vessels) also allow for long‐distance transportation of biomass and conversion in large‐scale biorefineries close to demand centers with similar GHG performance to biorefineries with a local biomass supply. © 2019 The Authors. Biofuels, Bioproducts, and Biorefining published by Society of Chemical Industry and John Wiley & Sons, Ltd.

Recycling of nitrogen-containing waste diapers for catalytic contaminant oxidation: Occurrence of radical and non-radical pathways

The transformation of waste biomass into nitrogen-doped carbon-based functional materials is recognized as an economical route for energy production and conversion. Waste diapers contain urea that could be used as a nitrogen source, were considered renewable biomass. BPA, a widely used environmental endocrine disruptor, produces estrogen effects in the human body and is characterized by low concentrations and high toxicity in the environment. Here, a simple method of obtaining cobalt embedded waste diaper carbon (Co-WDC) using abandoned diapers is reported and used for an advanced oxidation process. Co-WDC completely removed 20 mg L−1 BPA from a solution within 6 min with a degradation rate constant of 0.68 min−1. The LC–MS test revealed that BPA is decomposed into small molecules, and TOC was greatly reduced. Electron paramagnetic resonance and quenching experiments demonstrated the Co-WDC degradation system acted through two pathways, radical and non-radical pathway where 1O2 was the dominant species. Material characterization and discussion of the mechanism revealed that the introduction of Co mainly formed a metal-nitrogen structure that induced peroxymonosulfate to produce 1O2, which participated in BPA degradation in the Co-WDC system. This work should generate interest in the recycling of waste biomass for peroxymonosulfate activation and environmental modification.

Freestanding Polymer Assembly Conductor by Contact-Free Annealing

Molecular chain ordering and geometrical confinement of conjugated polymers determine the structural and electronic activity of entire organic systems. Here, we present a surface-tension induced spontaneous formation of freestanding conjugated polymer nanosheets followed by a contact-free annealing treatment to achieve the optimum crystallization and conductivity. Nanoconfinement in macroscopic crystalline polymer nanosheets produces mechanical robustness and high mobility. The conductivity of freestanding nanosheets displays an increase of 3 orders of magnitude from 4.2 × 10–3 to 5.5 S cm–1 through halogen induced charge-transfer interactions. Meanwhile, the densely compacted and freestanding electronic-active polymer nanosheets open up the route for thermal energy conversion with the output thermovoltage of 16.93 mV K–1.

Techno-economic analysis of producing liquid fuels from biomass via anaerobic digestion and thermochemical conversion

This paper discusses a preliminary design and a techno-economic analysis of a process that produces liquid hydrocarbon fuels from biomass through a combined biochemical and thermochemical process. The biochemical component involves anaerobic digestion (AD) of the biomass's biodegradable portion to produce biogas. Biogas is purified by removing contaminants and upgraded to liquid hydrocarbon fuel in a biogas to liquid facility (BGTL) via thermochemical conversion route. The BGTL process involves two major steps: tri-reforming to produce syngas (a mixture of CO and H2), and, Fischer-Tropsch Synthesis (FTS) to convert the syngas to a spectrum of hydrocarbons (synthetic crude). Separation and upgrading of the produced hydrocarbon mixture allows production of transportation fuels such as gasoline, jet fuel, and diesel.In order to evaluate the economics of the combined process a detailed process modelling was carried out using Aspen Plus® software. Bench-scale experimental results served as the basis of modelling the BGTL section of the plant, while the AD portion of the plant is based on empirical models selected from the literature validated by comparison with experimental results. Recent bench scale tests in our lab were used to determine processing parameters (yield, temperature, and pressure) for the reforming and FTS conversion.A plant capable of processing 90,000 tonne year−1 of wet biomass feed was designed and analyzed using the model. Results of the economic analysis estimate that a breakeven cost of diesel of $1.30 L-1 is achievable without the consideration of charging tipping fees to accept the biomass feedstock. Sensitivity study shows that the economics are significantly affected by the fixed capital investment (FCI) and less so by the operating expenses and interest rate. In addition, tipping fees and biomass feedstock cost have a substantial effect on the breakeven price of diesel.

CFD simulation of a fluidized bed reactor for biomass chemical looping gasification with continuous feedstock

Integrating the gasification process with the chemical looping technology presents a promising route for biomass conversion with the objective to obtain high quality syngas without air separation. In this study, the biomass gasification with iron-based oxygen carrier and continuous feedstock in the bubbling fluidized bed (BFB) fuel reactor has been investigated based on the computational fluid dynamics (CFD). The solid phases including fuel and oxygen carriers are modeled based on the pseudo-fluid assumption. The numerical model integrates the multi-fluid model and the chemical reaction models involving the decomposition and gasification of biomass and the heterogeneous reactions between gases and metal oxides. The predicted time-varying outlet concentrations of five gas components agree well with the experimental data from the literature. The impacts of the mixing and segregation behaviors between two solid phases on the gas composition distribution are analyzed. The effects of operation temperature, fuel feeding rate and steam content on the chemical looping gasification (CLG) performance are also investigated. The concentrations of CO and H2 as well as the gas yield and gasification efficiency increase while the concentrations of hydrocarbons and CO2 decrease with the escalating temperature because of the facilitation of higher temperature on the endothermic reactions. Raising the feeding rate of biomass leads to a higher gasification efficiency with more valuable syngas but a lower carbon conversion efficiency due to the relatively lower OC-fuel ratio. The gasification atmosphere containing 10–50% of steam also brings remarkable enhancements on the H2 concentration, gas yield and gasification efficiency.

Agent-based conceptual framework for energy and material synergy patterns in a territory with non-cooperative governance

Abstarct Circular economy is gaining momentum as an answer for migrating towards a sustainable paradigm. Many literature studies were conducted to assess the feasibility of heating networks based on industrial heat recovery and similarly for material reuse and recycling aiming to propose technical options for energy efficiency and resource use whether on the process scale or on a larger inter-sites level. In addition, reacting conversion systems create new valorization opportunities for the energy or material streams. In this perspective, a novel conceptual framework, incorporating reacting thermodynamic conversion systems to the material and energy integration problems in non-cooperative economic scheme, was proposed in this work. The application of the proposed methodological framework on a realistic industrial park demonstrated how to implement conversion processes in a territory. The non-usable stream in the investigated park is woody biomass for which three conversion routes were challenged being the wood to hydrogen, methane production and cogeneration.

Hydrothermal deglycosylation and deconstruction effect of steam explosion: Application to high-valued glycyrrhizic acid derivatives from liquorice

In this work, steam explosion (SE) was exploited as a green and facile process to deconstruct liquorice’s structure and deglycosylate glycyrrhizic acid (GL) to improve conversion and diffusion efficacy of GL and its hydrolyzed products. Results showed SE induced auto-hydrolysis of GL into glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG) and glycyrrhetinic acid (GA), by which 30.71% of GL conversion, 5.24% and 21.47% of GAMG and GA formation were obtained. GL hydrolytic pathways were revealed by reaction kinetics and thermodynamics, which possessed complex consecutive and parallel reactions with endothermic, non-spontaneous and entropy-decreasing features. SE referred to cause cleavage of the β-1,3 glycosidic bond in GL which was hydrolyzed to GA as a main product and GAMG and glucuronic acids as minor products. Diffusion of hydrolyzed products was accelerated by raising the diffusion coefficient and shortening the equilibrium time by over 90%. This work provides a sustainable and efficient route for product conversion and function enhancement of bioactive components.

One-pot bio-derived ionic liquid conversion followed by hydrogenolysis reaction for biomass valorization: A promising approach affecting the morphology and quality of lignin of switchgrass and poplar

The use of bio-derived ionic liquids (e.g., cholinium lysinate) in a one-pot process was evaluated on overall sugar and lignin yields as a function of two model woody and herbaceous feedstocks, switchgrass and poplar, with emphasis on the study of physical and chemical alterations in lignin structure, by performing a detailed mass balance analysis and chemical characterization. Multiple chromatographic and spectroscopic analytical techniques were applied tracking lignin reactivity and partitioning during the ionic liquid one-pot conversion. Depolymerization efficiency of the lignin-rich residue derived from the whole process was investigated as a function of different temperatures and pressures during catalytic hydrogenolysis by Ni(SO)4.This study validates the potential of ionic liquid one pot process as an integrated approach for full exploitation of lignocellulosic feedstocks. The insights gained will contribute to the design of future conversion routes for efficient biomass deconstruction and lignin valorization.

Carbon stabilised saponite supported transition metal-alloy catalysts for chemical CO2 utilisation via reverse water-gas shift reaction

Chemical CO2 upgrading via reverse water gas shift (RWGS) represents an interesting route for gas phase CO2 conversion. Herein, nature inspired clay-based catalysts are used to design highly effective materials, which could make this route viable for practical applications. Ni and transition metal promoted Ni saponite clays has been developed as highly effective catalysts for the RWGS. Saponite supported NiCu catalyst displayed a remarkable preference for the formation of CO over CH4 across the entire temperature range compared to the saponite supported NiCo and Ni catalysts. The NiCu sample is also highly stable maintaining ∼ 55% CO2 conversion and ∼ 80% selectivity for CO for long terms runs. Very importantly, when compared with reference catalysts our materials display significantly higher levels of CO2 conversion and CO selectivity. This confirmed the suitability of these catalysts to upgrade CO2-rich streams under continuous operation conditions.

Conversion of actinide nitrate surrogates into oxide using combustion synthesis process: A facile approach

In recent years, the focus of research in the conversion routes for the actinide nitrates into oxides for the generation IV nuclear fuel cycle have attracted rapidly growing interest. One process is the self-sustained exothermic reaction of Solution Combustion Synthesis (SCS) methodology. It was applied here to the reaction of an actinide surrogate Gd(NO3)3,6H2O with glycine in air to produce ∼10−3 mol amounts of Gd2O3. The primary process parameters were the Gd/glycine ratio and heating rate, which affected the ignition temperature of the precursor mixture. An optimum ratio of one and a heating rate of 10 K min−1 resulted in nearly complete SCS conversion over the 483–573 K temperature range and ultrafine gadolinia powders. The 100- to 500-fold swelling of the reactant mixture plays a dynamic role in the reactivity of the system. Final products were characterized by X-Rays Diffraction (XRD), surface area analysis, carbon content, and Scanning Electron Microscopy (SEM). The structural characteristics of the final gadolinia phases have been interpreted by the adiabatic flame temperature calculation.

Recent Progress in Direct Conversion of Methane to Methanol Over Copper-Exchanged Zeolites.

The conversion of methane into an easily transportable liquid fuel or chemicals has become a highly sought-after goal spurred by the increasing availability of cheap and abundant natural gas. While utilization of methane for the production of syngas and its subsequent conversion via an indirect route is typical, it is cost-intensive, and alternative direct conversion routes have been investigated actively. One of the most promising directions among these is the low-temperature partial oxidation of methane to methanol over a metal-loaded zeolite, which mimics facile enzymatic chemistry of methane oxidation. Thus mono-, bi-, and trinuclear oxide compounds of iron and copper stabilized on ZSM-5 or mordenite, which are structurally analogous to those found in methane monooxygenases, have demonstrated promising catalytic performances. The two major problems of theses metal-loaded zeolites are low yield to methanol and batch-like non-catalytic reaction systems challenging to extend to an industrial scale. In this mini-review, attention was given to the direct methane oxidation to methanol over copper-loaded zeolite systems. A brief introduction on the catalytic methane direct oxidation routes and current status of the applied metal-containing zeolites including the ones with copper ions are given. Next, by analyzing the extensive experimental and theoretical data available, the consensus among the researchers to achieve the target of high methanol yield is discussed in terms of zeolite topology, active species, and reaction parameters. Finally, the recent efforts on continuous methanol production from the direct methane oxidation aiming for an industrial process are summarized.

Design of graphene oxide by a one‐pot synthetic route for catalytic conversion of furfural alcohol to ethyl levulinate

AbstractBackgroundGraphene oxide (GO) has abundant oxygen‐containing functionalities such as hydroxyl groups and carboxyl groups with distinct acidities. This feature makes GO a potential solid acid catalyst for the acid‐catalyzed reactions such as the production of ethyl levulinate (EL), a platform chemical, from the acid‐treatment of furfuryl alcohol (FA). The structure and functionalities of GO are closely related to its catalytic performance, and thus it is necessary to establish the relationship between the chemical structure and the catalytic properties of GO. To achieve this aim, in this work, the GO catalysts were designed by a facile one‐pot synthetic route with no subsequent modification. By controlling the parameters of oxidation process in preparation, multiple functional groups were immobilized onto graphitic substrate, significantly impacting the catalytic activity of GO in the conversion of FA to EL in an ethanol (EtOH) medium.ResultsThe results showed that, the oxidation process significantly influenced the distribution of oxygen‐containing functionalities on the surface of GO. The amount of the oxygen‐containing functionalities can be adjusted by the oxidation parameters such as oxidizing agent equivalent, reaction time and temperature, while the organosulfate can only be remained at a moderate oxidation temperature. The existence of the synergistic effect between the oxygen‐containing functionalities and the organosulfate functionalities promoted the catalytic activity of GO for the acid‐catalyzed conversion of FA to EL.ConclusionsThis work provides a new strategy of design and development of functional graphene‐based catalysts for the acid‐catalyzed reactions, and lays foundation of the practicability of GO in biomass conversion. © 2019 Society of Chemical Industry

An Overview of Bio-oil Upgrading with High Hydrogen-containing Feedstocks to Produce Transportation Fuels: Chemistry, Catalysts, and Engineering

As an alternative to increasingly depleted traditional petroleum fuel, bio-oil has many advantages: high energy density, flexibility, easy storage and transportation. Nevertheless, bio-oil also presents some unwanted characteristics such as high viscosity, acidity, oxygen content and chemical instability. The process of bio-oil upgrading is necessary before utilization as transportation fuels. In addition, the bio-oil has low effective hydrogen/ carbon molar ratio (H/Ceff) which may lead to coke formation and hence deactivation of the catalyst during the upgrading process. Therefore, it seemed that co-refining of biooil with other higher hydrogen-containing feedstocks is necessary. This paper provides a broad review of the bio-oil upgrading with high hydrogen-containing feedstocks to produce transportation fuels: chemistry, catalyst, and engineering research aspects were discussed. The different thermochemical conversion routes to produce bio-oil and its physical-chemical properties are discussed firstly. Then the bio-oil upgrading research using traditional technologies and common catalysts that emerged in recent years are briefly reviewed. Furthermore, the applications of high H/Ceff feedstock to produce high-quality of bio-oil are also discussed. Moreover, the emphasis is placed on co-refining technologies to produce transportation fuels. The processes of co-refining bio-oil and vacuum gas oil in fluid catalytic cracking (FCC) unit for transportation fuels from laboratory scale to pilot scale are also covered in this review. Co-refining technology makes it possible for commercial applications of bio-oil. Finally, some suggestions and prospects are put forward.

CO2 fixation for malate synthesis energized by starch via in vitro metabolic engineering

Carbon dioxide (CO2) is an appealing carbon feedstock for the sustainable production of biocommodities. Here we designed three in vitro artificial enzymatic pathways featuring the ATP-excess, ATP-deficit, and ATP-balanced pathways for the biotransformation of starch and CO2 to malate. This ATP-balanced pathway without exogenous ATP donors can auto-regulate its carbon fluxes from glyceraldehyde 3-phosphate to 3-phosphoglycerate via either the ATP-generating pathway (a part of glycolysis) or no-ATP-generating pathway from a hyperthermophilic archaeon Thermococcus kodakarensis. The ATP-balanced pathway enabled to produce up to 52.4 mM malate with 95.3% of the theoretical yield, that is, 2 mol of malate synthesized from 1 mol of glucose of starch and 2 mol of CO2. This pathway also enabled to produce high-yield malate regardless of ATP/ADP ratios. Anaerobic reaction conditions and/or the addition of a reducing agent dithiothreitol were of importance for creating an anoxic environment for biocatalysis of enzyme cocktails and for mitigating the deactivation of enzymes and degradation of intermediates. This new pathway could provide a green route for direct conversion of CO2 to many building blocks, a promising alternative of petrochemical-based production of biocommodities.

A Simple Route for the Direct Conversion of Waste Plastic to Hafnium Carbide Nanoparticles at Low Temperature

A Simple Route for the Direct Conversion of Waste Plastic to Hafnium Carbide Nanoparticles at Low Temperature