Showing papers on "Hydrocarbon published in 2020"

Transforming carbon dioxide into jet fuel using an organic combustion-synthesized Fe-Mn-K catalyst

Abstract: With mounting concerns over climate change, the utilisation or conversion of carbon dioxide into sustainable, synthetic hydrocarbons fuels, most notably for transportation purposes, continues to attract worldwide interest. This is particularly true in the search for sustainable or renewable aviation fuels. These offer considerable potential since, instead of consuming fossil crude oil, the fuels are produced from carbon dioxide using sustainable renewable hydrogen and energy. We report here a synthetic protocol to the fixation of carbon dioxide by converting it directly into aviation jet fuel using novel, inexpensive iron-based catalysts. We prepare the Fe-Mn-K catalyst by the so-called Organic Combustion Method, and the catalyst shows a carbon dioxide conversion through hydrogenation to hydrocarbons in the aviation jet fuel range of 38.2%, with a yield of 17.2%, and a selectivity of 47.8%, and with an attendant low carbon monoxide (5.6%) and methane selectivity (10.4%). The conversion reaction also produces light olefins ethylene, propylene, and butenes, totalling a yield of 8.7%, which are important raw materials for the petrochemical industry and are presently also only obtained from fossil crude oil. As this carbon dioxide is extracted from air, and re-emitted from jet fuels when combusted in flight, the overall effect is a carbon-neutral fuel. This contrasts with jet fuels produced from hydrocarbon fossil sources where the combustion process unlocks the fossil carbon and places it into the atmosphere, in longevity, as aerial carbon - carbon dioxide.

The effect of variable operating parameters for hydrocarbon fuel formation from CO2 by molten salts electrolysis

Abstract: The emission of CO2 has been increasing day by day by growing world population, which resulted in the atmospheric and environmental destruction. Conventionally different strategies, including nuclear power and geothermal energy have been adopted to convert atmospheric CO2 to hydrocarbon fuels. However, these methods are very complicated due to large amount of radioactive waste from the reprocessing plant. The present study investigated the effect of various parameters like temperature (200–500 °C), applied voltage (1.5–3.0 V), and feed gas (CO2/H2O) composition of 1, 9.2, and 15.6 in hydrocarbon fuel formation in molten carbonate (Li2CO3–Na2CO3–K2CO3; 43.5:31.5:25 mol%) and hydroxide (LiOH–NaOH; 27:73 and KOH–NaOH; 50:50 mol%) salts. The GC results reported that CH4 was the predominant hydrocarbon product with a lower CO2/H2O ratio (9.2) at 275 °C under 3 V in molten hydroxide (LiOH–NaOH). The results also showed that by increasing electrolysis temperature from 425 to 500 °C, the number of carbon atoms in hydrocarbon species rose to 7 (C7H16) with a production rate of 1.5 μmol/h cm2 at CO2/H2O ratio of 9.2. Moreover, the electrolysis to produce hydrocarbons in molten carbonates was more feasible at 1.5 V than 2 V due to the prospective carbon formation. While in molten hydroxide, the CH4 production rate (0.80–20.40 μmol/h cm2) increased by increasing the applied voltage from 2.0–3.0 V despite the reduced current efficiencies (2.30 to 0.05%). The maximum current efficiency (99.5%) was achieved for H2 as a by-product in molten hydroxide (LiOH–NaOH; 27:73 mol%) at 275 °C, under 2 V and CO2/H2O ratio of 1. Resultantly, the practice of molten salts could be a promising and encouraging technology for further fundamental investigation for hydrocarbon fuel formation due to its fast-electrolytic conversion rate and no utilization of catalyst.

Pyrolysis kinetics behaviour and thermal pyrolysis of Samanea saman seeds towards the production of renewable fuel

Abstract: The present study addresses pyrolysis behaviour and potential of Samanea saman seeds (SS) towards its bioenergy potential using thermogravimetric analyzer and in a cylindrical pyrolyzer (semi-batch reactor). Pyrolysis kinetic behaviour of biomass was carried out using Kissinger, Distributed Activation Energy Model (DAEM) and Miura-Maki-Integral method (MMI) while thermal pyrolysis was carried out in a cylindrical shaped semi-batch reactor. Kinetic results confirmed that the average activation energy was found 118.24 kJ mol−1, 168.70 kJ mol−1, and 97.87 kJ mol−1 for Kissinger, DAEM, and MMI model respectively. Further, thermal pyrolysis of SS biomass yielded 44.20 wt% yield of pyrolytic liquid (31.20 wt% pyrolytic oil/organic oil and 13 wt% aqueous fraction). Characterization results of pyrolytic oil showed the presence of higher viscosity (86.01 cSt), higher oxygen content (33.11%), and lower ash content (0.46 wt%) and gross heating value. FTIR analysis confirmed mainly the presence of aromatics, acid, alkene, water, and protein impurities. Gas Chromatography (GC) results declared, an increase in hydrocarbon and hydrogen gas with an increase in temperature while reduced the generation of CO and CO2. Further, GC-MS analysis of pyrolytic oil revealed the presence of higher acids (19.46%), phenols (11.01%) ethers (11.12%) and ester (7.33%) which is a potent source of oxygenated compounds. Characterization results of biochar showed the presence of higher gross heating value (23.14 MJ kg), carbon content (62.66%), volatile matter (34.15%) and lower moisture (5.14%) and BET surface area (8.20 m2 g−1). Combining these results, it can be suggested that SS biomass has the potential to produce renewable fuel and chemicals, while biochar can be used for various applications.

Catalytic pyrolysis of pinewood over ZSM-5 and CaO for aromatic hydrocarbon: Analytical Py-GC/MS study

Abstract: A higher amount of oxygenates is the main constraint for higher yield and quality of aromatics in catalytic pyrolysis while a study of hydrocarbon production with a balance of reactive species lies importance in the catalytic upgrading of pyrolytic vapor. Catalytic pyrolysis of pinewood sawdust over acidic (ZSM-5) and basic (CaO) catalyst was conducted by means of Py-GC/MS to evaluate the effect of biomass to catalyst loading ratio on aromatic hydrocarbon production. Catalytic pyrolysis with four different biomass to catalyst ratios (0.25:1, 0.5:1, 1:1, and 2:1) and non-catalytic pyrolysis were conducted. It has been obtained that ZSM-5 showed better catalytic activity in terms of a high fraction of aromatic hydrocarbon. The ZSM-5 catalyst showed a potential on the aromatization as the yield of aromatic hydrocarbon was increased with a higher amount of ZSM-5 catalyst and the highest yield of aromatics (42.19 wt %) was observed for biomass to catalyst ratio of 0.25:1. On the other hand, basic CaO catalyst was not selective to aromatic hydrocarbon from pinewood sawdust but explored high deacidification reaction in pyrolytic vapor compared to ZSM-5 catalyst, whereas non-catalytic pyrolysis resulted in acidic species (13.45 wt %) and phenolics (46.5 wt %). Based on the results, ZSM-5 catalyst can only be suggested for catalytic pyrolysis of pinewood sawdust for aromatic hydrocarbon production.

Activated Porous Carbon with an Ultrahigh Surface Area Derived from Waste Biomass for Acetone Adsorption, CO2 Capture, and Light Hydrocarbon Separation

Abstract: A well-developed porous structure and ultrahigh surface area of porous carbons are essential for challenging the gas adsorption. Herein, we synthesized biomass-based porous carbon with a facile and effectively adjustable pore structure. The maximum surface area of activated carbon is up to 3839 m2 g–1, and high micropores and narrow mesopores (1.94 mL g–1 with d < 3 nm) are obtained. The tailored porous carbons are extensively applied in the energy and environment fields, such as their improved acetone adsorption, CO2 capture, and light hydrocarbon separation. The porous carbon exhibits record-high acetone (i.e., 26.2 mmol·g–1 at 18 kPa and 25 °C) and CO2 uptake (i.e., 29.5 mmol·g–1 at 30 bar and 25 °C) among reported carbons at relative high pressure. Besides, the UC800 exhibits superior C2H6 and C3H8 uptake of 7.19 and 12.02 mmol·g–1, respectively. The C2H6/CH4 and C3H8/CH4 selectivity of the UC800 are up to 9.1–14.6 and 41.8–63.2, respectively. The simple method can open the door to design and develop highly porous carbons with a desired porous structure for the gas adsorption application.

Mesoporous carbon as an effective support for Fe catalyst for CO2 hydrogenation to liquid hydrocarbons

Abstract: Identifying highly efficient catalysts for direct CO2 hydrogenation to liquid hydrocarbons is crucial for CO2 utilization via chemical conversion using renewable resources, the so-called Power-to-Liquids. In this study, well-defined mesoporous carbon (MPC) of 6.9 nm pore size was synthesized as a support material for Fe oxycarbide nanoparticles, which serve as active sites for the CO2 hydrogenation reaction, combining reverse water-gas shift and Fischer-Tropsch reactions. The unique physicochemical properties of MPC favored the formation of an active carbidic Fe phase and the rapid diffusion of produced hydrocarbons which resulted in an enhanced CO2 conversion and long-chain hydrocarbon selectivity. As a result, the MPC supported Fe catalyst showed C5+ hydrocarbon selectivity of 44.5% with a CO2 conversion rate of 50.6% (300 °C, 2.5 MPa, H2/CO2 = 3).

Ambient-pressure and low-temperature upgrading of lignin bio-oil to hydrocarbons using a hydrogen buffer catalytic system

Abstract: Catalytic hydrodeoxygenation is an essential step for bio-oil upgrading. However, hydrodeoxygenation usually requires a high hydrogen pressure and high temperature due to the good stability of the C–O bonds. Here we report an effective multiphase hydrodeoxygenation of lignin-based bio-oil at temperatures <100 °C and hydrogen pressures <1 atm using a synergetic catalyst system that consists of a low redox potential H4SiW12O40 (SiW12) and suspended Pt-on-carbon (Pt/C) particles. We propose that SiW12 plays three critical roles in bio-oil hydrodeoxygenation. First, it quickly oxidizes the H2 gas to form reduced SiW12 in the presence of Pt/C. Second, it transfers both electrons and H+ ions to the bulk phase to form active H* or H2 on the Pt/C surface. Third, the formation of the oxonium ion in a SiW12 superacid solution reduces the deoxygenation energy. The SiW12-enhanced proton-transfer hydrodeoxygenation mechanism is supported by density functional theory computations. As a result of the hydrogen buffer and acidic effect, up to a 90% yield of hydrocarbons (cyclohexane, benzene and their derivatives) was achieved from the hydrodeoxygenation of phenol and its derivatives. Bio-oil derived from biomass has great potential as a more sustainable fuel but its formation typically relies on energy-intensive processes. Liu et al. show how a tri-phase hydrogen-transfer catalytic system can drive hydrodeoxygenation in water under mild conditions to achieve up to 90% hydrocarbon yield.

Light Hydrocarbon Separations Using Porous Organic Framework Materials

Abstract: Light hydrocarbons (C1 -C3 ) are used as basic energy feedstocks and as commodity organic compounds for the production of many industrially necessary chemicals. Due to the nature of the raw materials and production processes, light hydrocarbons are generated as mixtures, but the high-purity single-component products are of vital importance to the petrochemical industry. Consequently, the separation of these C1 -C3 products is a crucial industrial procedure that comprises a significant share of the total global energy consumption per year. As a complement to traditional separation methods (distillation, partial hydrogenation, etc.), adsorptive separations using porous solids have received widespread attention due to their lower energy costs and higher efficiency. Extensive research has been devoted to the use of porous materials such as zeolites and metal-organic frameworks (MOFs) as solid adsorbents for these key separations, owing to the high porosity, tunable pore structures, and unsaturated metal sites present in these materials. Recently, porous organic framework (POF) materials composed of organic building blocks linked by covalent bonds have also shown excellent properties in light hydrocarbon adsorption and separation, sparking interest in the use of these materials as adsorbents in separation processes. This Minireview summarizes the recent advances in the use of POFs for light hydrocarbon separations, including the separation of mixtures of methane/ethane, methane/propane, ethylene/ethane, acetylene/ethylene, and propylene/propane, while highlighting the relationships between the structural features of these materials and their separation performances. Finally, the difficulties, challenges, and opportunities associated with leveraging POFs for light hydrocarbon separations are discussed to conclude the review.

Production of green diesel from catalytic deoxygenation of chicken fat oil over a series binary metal oxide-supported MWCNTs

Abstract: Deoxygenation processes that exploit milder reaction conditions under H2-free atmospheres appear environmentally and economically effective for the production of green diesel. Herein, green diesel was produced by catalytic deoxygenation of chicken fat oil (CFO) over oxides of binary metal pairs (Ni–Mg, Ni–Mn, Ni–Cu, Ni–Ce) supported on multi-walled carbon nanotubes (MWCNTs). The presence of Mg and Mn with Ni afforded greater deoxygenation activity, with hydrocarbon yields of >75% and n-(C15 + C17) selectivity of >81%, indicating that decarboxylation/decarbonylation (deCOx) of CFO is favoured by the existence of high amount of lower strength strong acidic sites along with noticeable strongly basic sites. Based on a series of studies of different Mg and Mn dosages (5–20 wt%), the oxygen free-rich diesel-range hydrocarbons produced efficiently by Ni10–Mg15/MWCNT and Ni10–Mn5/MWCNT catalysts yielded >84% of hydrocarbons, with n-(C15 + C17) selectivity of >85%. The heating value of the green diesel obtained complied with the ultra-low sulphur diesel standard.

An efficient bifunctional Ru-NbOPO4 catalyst for the hydrodeoxygenation of aromatic ethers, phenols and real bio-oil

Abstract: An efficient bifunctional NbOPO4 supported Ru catalyst (Ru-NbOPO4) was applied to the hydrodeoxygenation of aromatic ethers and phenols and the upgrading of bio-oil. Characterization results revealed that the Ru-NbOPO4 catalyst possessed strong acidity, including Lewis and Bronsted acids. The Lewis acid sites originated from the Nb O bonding structures, including slightly distorted octahedral NbO6, regular tetrahedral NbO4 and highly distorted octahedral NbO6. In combination with the strong acidity of the Nb O species and excellent hydrogenation activity of the metallic Ru, the bifunctional Ru-NbOPO4 catalyst exhibited an excellent catalytic activity in the hydrodeoxygenation of aromatic ethers and phenols with different structures, and even real bio-oil to alkanes. The hydrocarbon yield after real bio-oil upgradation was up to 88.2 %. Carbon deposition and enlargement of the Ru nanoparticles resulted in slight deactivation of the catalyst. The catalytic activity could be mostly recovered after being calcined and reduced.

Plasma-Based CH4 Conversion into Higher Hydrocarbons and H2: Modeling to Reveal the Reaction Mechanisms of Different Plasma Sources.

Abstract: Plasma is gaining interest for CH4 conversion into higher hydrocarbons and H2. However, the performance in terms of conversion and selectivity toward different hydrocarbons is different for different plasma types, and the underlying mechanisms are not yet fully understood. Therefore, we study here these mechanisms in different plasma sources, by means of a chemical kinetics model. The model is first validated by comparing the calculated conversions and hydrocarbon/H2 selectivities with experimental results in these different plasma types and over a wide range of specific energy input (SEI) values. Our model predicts that vibrational-translational nonequilibrium is negligible in all CH4 plasmas investigated, and instead, thermal conversion is important. Higher gas temperatures also lead to a more selective production of unsaturated hydrocarbons (mainly C2H2) due to neutral dissociation of CH4 and subsequent dehydrogenation processes, while three-body recombination reactions into saturated hydrocarbons (mainly C2H6, but also higher hydrocarbons) are dominant in low temperature plasmas.