Modelling of Jatropha Oil Hydrocracking in a Trickle-Bed Reactor to Produce Green Fuel

Trickle-bed reactor (TBR) modelling to produce green fuel via hydrocracking of jatropha oil using silica-alumina-supported Ni-W catalysts was performed in this research. The objectives of this study are to obtain a TBR with good heat transfer and the optimum condition for high purities of products. A two-dimensional axisymmetric model with a diameter of 0.1 m and a length of 10 m was used as a representative of the actual TBR system. Heterogeneous phenomenological models were developed considering mass, energy, and momentum transfers. The optimisation was conducted to obtain the highest green fuel purity by varying catalyst particle diameter, inlet gas velocity, feed molar ratio, and inlet temperature. The simulation shows that a TBR with an aspect ratio of 100 has achieved a good heat transfer. The diesel purity reaches 44.22% at 420°C, kerosene purity reaches 21.39% at 500°C, and naphtha purity reaches 25.30% at 500°C. The optimum condition is reached at the catalyst diameter of 1 mm, the inlet gas velocity of 1 cm/s, the feed molar ratio of 105.5, and the inlet temperature at 500°C with the green fuel purity of 69.4%.

Effects of Monomer Compatibility on Sizing Performance of Chitosan-g-P(MA-co-AM)

To impart good application performance to chitosan (CS) sizes for high polyester content warp yarns, methyl acrylate (MA) and acrylamide (AM) monomers, with a variation in feed molar ratio from 1:9 to 4:6, were grafted onto the molecular chains of native CS to obtain CS-g-P(MA-co-AM) products, with similar grafting ratios through a K2S2O8-NaHSO3 redox system. Effects of monomer compatibility of MA and AM on sizing performance of the CS-g-P(MA-co-AM) for high polyester content warp were studied. Grafting MA and AM with rational compatibility onto the molecular chains of CS is an effective method to improve the application performance of CS sizes. In view of the overall performance of the CS-g-P(MA-co-AM) sizes, the appropriate feed molar ratio of MA/AM should be 3:7.

Process Intensification of Methane Production via Catalytic Hydrogenation in the Presence of Ni-CeO2/Cr2O3 Using a Micro-Channel Reactor

A slight amount of Cr2O3 segregation in 40 wt% NiO/Ce0.5Cr0.5O2 was presented at the surface. The best catalytic performance towards the reaction was achieved at 74% of CO2 conversion and 100% CH4 selectivity at 310 °C, the reactant (H2/CO2) feed molar ratio was 4, and the WHSV was 56,500 mlN·h−1·g−1cat. The mechanistic pathway was proposed through carbonates and formates as a mediator during CO2 and H2 interaction. Activation energy was estimated at 4.85 kJ/mol, when the orders of the reaction were ranging from 0.33 to 1.07 for nth-order, and 0.40 to 0.53 for mth-order.

A Theoretical Analysis on a Multi-Bed Pervaporation Membrane Reactor during Levulinic Acid Esterification Using the Computational Fluid Dynamic Method

Pervaporation is a peculiar membrane separation process, which is considered for integration with a variety of reactions in promising new applications. Pervaporation membrane reactors have some specific uses in sustainable chemistry, such as the esterification processes. This theoretical study based on the computational fluid dynamics method aims to evaluate the performance of a multi-bed pervaporation membrane reactor (including poly (vinyl alcohol) membrane) to produce ethyl levulinate as a significant fuel additive, coming from the esterification of levulinic acid. For comparison, an equivalent multi-bed traditional reactor is also studied at the same operating conditions of the aforementioned pervaporation membrane reactor. A computational fluid dynamics model was developed and validated by experimental literature data. The effects of reaction temperature, catalyst loading, feed molar ratio, and feed flow rate on the reactor’s performance in terms of levulinic acid conversion and water removal were hence studied. The simulations indicated that the multi-bed pervaporation membrane reactor results to be the best solution over the multi-bed traditional reactor, presenting the best simulation results at 343 K, 2 bar, catalyst loading 8.6 g, feed flow rate 7 mm3/s, and feed molar ratio 3 with levulinic acid conversion equal to 95.3% and 91.1% water removal.

Effects of Process Factors on Carbon Dioxide Reforming of Methane over Ni/SBA-15 Catalyst

The process of CO2 reformation of CH4 was conducted over a 5% Ni/SBA-15 catalyst under various experimental conditions. Operating temperature (600-750 �C), gas hourly space velocity (4000-12000 hr-1), and CO2/CH4 feed molar ratio (0.67-1.50) were selected as independent parameters (factors). Process performances were evaluated as conversions of CH4 (21.1-79.6%) and CO2 (42.4-98.7%) as well as H2/CO product molar ratio (0.573-0.992). All process performances were enhanced at higher levels of temperature and low values of gas velocity. An increase in feed molar ratio has determined a significant increase in CH4 conversion and a slighter decrease in CO2 conversion and H2/CO molar ratio. A statistical model based on a 23 factorial plan was used to predict the process performances depending on its factors.

Thermal analysis and melt spinnability of poly(acrylonitrile-co-methyl acrylate) and poly(acrylonitrile-co-dimethyl itaconate) copolymers

This work investigated the cyclization possibility and melt spinnability of carbon fiber precursors, poly(acrylonitrile-co-methyl acrylate) (AN/MA) and poly(acrylonitrile-co-dimethyl itaconate) (AN/DMI). The onset temperature of cyclization of the AN/DMI copolymer is lower than that of the AN/MA copolymer and also the polyacrylonitrile (PAN) homopolymer. The enthalpy ( ΔH) of the AN/DMI copolymer is about 3–4 times that of the PAN homopolymer and about 1.8 times that of the AN/MA copolymer, indicating that the degree of cyclization of the AN/DMI copolymer is relatively higher. The melt dwell time of the AN/DMI copolymer is increased to about 3–5 times that of the AN/MA copolymer, especially when synthesized with a feed molar ratio of AN/DMI = 85/15. The AN/DMI copolymer (AN/DMI = 85/15) has the longest melt dwell time, 24.8 min, at the lowest melting temperature, 190oC, among all the PAN-related copolymers synthesized herein. Furthermore, the AN/DMI copolymer (AN/DMI = 85/15) can be rapidly cyclized at the cyclization temperature of 260℃, which is 25℃ lower than that of the AN/MA copolymer (AN/MA = 85/15). In short, this work demonstrates that the carbon fiber precursor made by the AN/DMI copolymer (AN/DMI = 85/15) will be superior to that of the AN/MA copolymer (AN/MA = 85/15) with respect to the melt spinnability and cyclization at low temperature.

Nickel and cobalt phosphides as effective catalysts for oxygen removal of dibenzofuran: role of contact time, hydrogen pressure and hydrogen/feed molar ratio

The catalytic activity of nickel and cobalt phosphides, with a metal loading of 5 wt.%, supported on silica was investigated in the hydrodeoxygenation reaction (HDO) of dibenzofuran (DBF) as a model oxygenated compound at different contact times, H2 pressures and H2/DBF molar ratios.

A Novel Process Simulation Study of Coalbed Methane Enrichment by Solvent

A type of novel solvent absorption method using propyl ether as absorbent was proposed, which the coalbed methane (CBM) was concentrated and simulated in the form of physical absorption. The reasonable process had been designed and analyzed by Aspen Plus v7.3 . Through the simulation method PSRK, effects of the number of theoretical stages and the optimal operating pressure, temperature, amount of fresh absorbent added were studied respectively. The optimal enrichment effect of CH4/N2 feed ratio was determined. Simulation results show that when the feed molar ratio of CH4/N2 is 3:7, it can improve methane concentration to 67.44% with a recovery ratio of 87.11%. When feeding methane concentration increased to more than 50%, it can be enriched to more than 80%, which is suitable for the CBM civil and industrial utilization value. The enrichment process designed can provide an idea for the enrichment of CBM.

Transesterification of Sunflower Oil in Microreactors

KOH catalyzed transesterification of sunflower oil using methanol has been studied in different types of microreactors. All the microreactors consist of a serpentine microchannel etched in a glass chip but have different types of microfluidic junctions (dispersing devices). First microreactor consists of a T-type microfluidic junction. The second microreactor has a †-type microfluidic junction. The third microreactor uses a split and recombine micromixer to generate the dispersion. Effects of temperature, flow rate, and feed molar ratio on the conversion of triglyceride (TG) have been studied. In some cases, conversion of TG is not found to change monotonically with change in flow rate. An attempt has been made to explain this seemingly unusual trend, and the explanations are substantiated using the liquid–liquid two-phase flow patterns observed using a high-speed image acquisition system. The results from the experiments conducted in this study indicate that it is possible to get very high TG conversion (>90%) with residence time less than a minute.

Hydrogenation of Tetralin over Supported Ni and Ir Catalysts

Selective hydrogenation and ring opening (SRO) of tetrahydronaphthalene (tetralin) was studied over nickel and iridium supported catalysts in the context of the removal of polynuclear aromatics from diesel fuel. The tetralin hydrogenation was carried out in a fixed-bed reactor at 270°C, using H2pressure of 30 bars, WHSV of 2.3 h−1, and H2/feed molar ratio of 40; the resultant products were analyzed by GC and GC-MS. The Ir/SiO2catalyst gave 85% of tetralin conversion and 75.1% of decalin products selectivity whereas Ni/SiO2catalyst showed an unprecedented high catalytic performance with 88.3% of tetralin conversion and 93% of decalin products selectivity. The catalysts were characterized by using different characterization techniques such as XRD, TPR, and HR-TEM to know the physicochemical properties as well as active sites in the catalysts.