Search Results (57)

Coal-based methanol-to-olefins (MTO) is a vital technology for establishing the “coal/natural gas-to-olefins” pathway. In this study, an industrial MTO unit of a Chinese coal chemical enterprise was modeled and optimized using plant data. For the reactor-regenerator system, a lumped kinetic model based on the SAPO-34 catalyst was validated against 4 industrial measured datasets, showing high accuracy in predicting effluent distributions and spent catalyst coke content. Multifactor optimization across another 4 measured operating cases increased the total yield of light olefins (ethylene and propylene) by up to 2.22%. Subsequently, a separation flowsheet based on measured plant data was developed in Aspen Plus using the RK-Soave and ENRTL-RK methods, resulting in low relative errors (0.12% for ethylene and 0.05% for propylene). Under the constraints of meeting product quality specifications, sensitivity analysis based on the optimized simulated yield of light olefins was conducted to optimize the side-draw rate of the ethylene column and the reflux ratio of the propylene column, corresponding to an annual energy saving of approximately 1.196 × 10⁸ kW·h, together with an annual increase of 168 t in ethylene production. This work provides a quantitative reference for optimizing operating parameters and reducing energy consumption in industrial units. The optimized operational boundaries proposed herein are within the controllable range of the actual plant, providing operators with actionable guidelines for real-time process intensification and energy reduction. Full article

The methanol-to-olefins (MTO) process offers a viable alternative to traditional naphtha cracking for producing light olefins, providing flexibility in feedstock sources and the potential for reduced energy consumption. This study presents a detailed plant-wide design of an MTO process, developed and optimized to increase ethylene and propylene yields while reducing energy consumption. The methodology includes comprehensive reactor modeling of a fast fluidized-bed reactor–regenerator system, accounting for coke formation kinetics, along with rigorous process simulation for the subsequent separation and purification of products. A six-column distillation train has been designed and optimized for the recovery of polymer-grade ethylene and propylene, while dual-stage CO₂ absorption units ensure complete removal of carbon dioxide. Pinch analysis is used to identify opportunities for heat integration, resulting in an optimized heat-exchanger network that significantly reduces the need for external heating and cooling utilities. The results show that the optimized MTO design achieves a methanol conversion rate of over 99.9% and produces a propylene-rich product stream with a propylene-to-ethylene ratio of approximately 1.8, while maintaining a high purity level exceeding 99.5%. By implementing heat integration and recycling by-products, including using off-gas methane as furnace fuel and repurposing waste heat for steam generation, the plant reduces utility requirements by more than 85%, significantly improving energy efficiency. An economic evaluation shows a favorable payback period of approximately 5.4 years and an internal rate of return of 15–16%, confirming the viability and industrial potential of the integrated MTO process for sustainable olefin production. Full article

Municipal solid waste (MSW) recycling is constrained by contamination, heterogeneity, and infrastructure built around material-specific pathways. We introduce effectiveness-normalized greenhouse gas (GHG) emissions as a system-level metric that adjusts reported process burdens by feedstock eligibility (Effectiveness Fraction, EF) and carbon recovery efficiency (CRE) to reflect real-world MSW conditions. Using published LCA data and engineering estimates, we benchmark six pathways, mechanical recycling, PET depolymerization, enzymatic depolymerization, pyrolysis, supercritical water gasification (SCWG), and Regenerative Robust Gasification (RRG), at the scale of mixed MSW. Normalizing for EF and CRE reveals large differences between process-level and system-level performance. Mechanical recycling and PET depolymerization show low process intensities yet high normalized impacts because they can treat only a small share of plastics in MSW. SCWG performs well at broader eligibility. RRG, a plasma-assisted molten-bath approach integrated with methanol synthesis, maintains the lowest normalized impact (~1.6 t CO₂e per ton of recycled polymer) while accepting virtually all organics in MSW and vitrifying inorganics. Modeled methanol yields are ~200–300 gal·t⁻¹ without external hydrogen and up to ~800 gal·t⁻¹ with renewable methane reforming. The metric clarifies trade-offs for policy and investment by rewarding technologies that maximize diversion and carbon retention. We discuss how effectiveness-normalized results can be incorporated into LCA practice and Extended Producer Responsibility (EPR) frameworks and outline research needs in techno-economics, regional scalability, hydrogen sourcing, and uncertainty analysis. Findings support aligning infrastructure and procurement with robust, scalable routes that deliver circular manufacturing from heterogeneous MSW. Full article

The increasing resistance of pathogens to conventional antibiotics has necessitated the search for novel antimicrobial agents from medicinal plants. Nelsonia canescens—a plant traditionally used in Africa and Asia for the management of health issues, such as viral infections, cardiovascular diseases, and inflammation—has been reported to demonstrate antimicrobial activity and has been investigated for its bioactive constituents. The whole plant was collected, air-dried, and extracted using 70% methanol. The crude methanol extract was partitioned into hexane, chloroform, ethyl acetate, and butanol fractions. The ethyl acetate fraction was subjected to column chromatography and gel filtration, leading to the isolation of a compound coded A₁. The structure of compound A₁ was established through UV, FTIR, NMR (¹H, ¹³C, DEPT, COSY, HMQC, and HMBC), and chemical tests. Compound A₁ was identified as a 2*-hydroxy-4*-phenyl-(2**-hydroxy-ethyl)-3′-(4′′′→1′′) glucose-rhamnose-3-hydroxy phenyl ester, a flavonoid derivative. A spectral analysis confirmed its structure, with key signals including olefinic protons (δ 6.30 and 7.62) in the trans-configuration, aromatic protons, and sugar moieties. The compound exhibited a melting point of 105–107 °C and was partially soluble in chloroform but fully soluble in methanol, suggesting that the compound is highly polar in nature. This is the first report on the isolation of the 2*-hydroxy-4*-phenyl-(2**-hydroxy-ethyl)-3′-(4′′′→1′′) glucose-rhamnose-3-hydroxy phenyl ester from Nelsonia canescens, contributing to the taxonomy of the plant. The compound’s structural features suggest potential bioactive properties, warranting further investigation into its pharmacological applications through in vitro and molecular docking studies. Full article

Alkali metal-modified M-ZSM-5 zeolites (M: Li⁺, Na⁺, K⁺) were synthesized by cationic exchange and characterized using ICP-MS, XRD, N₂ adsorption–desorption, Py-IR and NH₃-TPD techniques to evaluate their elemental composition, structure, textural and acidic properties. In addition, XPS and DFT calculations were employed to study the effects of metal ion doping on the electronic structure and catalytic behavior. The latter catalytic performance was assessed in the methanol-to-olefin (MTO) reaction. The results showed that alkali metal doping facilitated the enhancement of the zeolite structural stability, adjustment of acid density, and increase in the adsorption energy of light olefins onto the active sites. During the reaction, olefin products shifted from Brønsted acid sites to alkali metal sites, effectively minimizing hydrogen transfer reactions. This change in the active site nature promoted the olefin cycle, resulting in higher yields in propylene and butylenes, reduced coke deposition, and prolonged catalyst lifetime. Among all zeolites, Li-exchanged ZSM-5 exhibited the best and extending the catalyst lifetime by 5 h. Full article

This research work seeks to introduce eco-friendly, low-carbon, and high-octane biofuel gasoline production using a synergistic approach. Four types of high-octane gasoline, including SynergyFuel-92, SynergyFuel-95, SynergyFuel-98, and SynergyFuel-100, were generated, emphasizing the deliberate combination of petroleum-derived gasoline fractions using reformate, isomerate, and delayed coking (DC) naphtha with octane-boosting compounds—bio-methanol and bio-ethanol. A set of tests have been performed to examine the effects of antiknock properties, density, oxidation stability, distillation range characteristics, hydrocarbon composition, vapor pressure, and the volatility index on gasoline blends. The experimental results indicated that the gasoline blends made from biofuel (SynergyFuel-92, -95, -98, and 100) showed adherence to important fuel quality criteria in the USA, Europe, and China. These blends had good characteristics, such as low quantities of benzene and sulfur, regulated levels of olefins and aromatics, and good distillation qualities. By fulfilling these strict regulations, Synergy Fuel is positioned as a competitive and eco-friendly substitute for traditional gasoline. The results reported that SynergyFuel-100 demonstrated the strongest hot-fuel-handling qualities and resistance to vapor lock among all the mentioned Synergy Fuels. Finally, the emergence of eco-friendly, low-carbon, and high-octane biofuel gasoline production with synergistic benefits is a big step in the direction of sustainable transportation. Full article

Microwave-assisted ionothermal strategies offer an effective pathway for rapid zeolite crystallization under mild conditions, while conventional ionothermal approaches are still constrained by prolonged crystallization cycles that limit their industrial applicability. Herein, we report a microwave-activated, ionic liquid-mediated synthesis strategy that enables the precise modulation of crystallization kinetics and composite assembly. By introducing ZSM-5 seeds into the ionic liquid system, the nucleation and growth of AlPO₄-5 were significantly accelerated, reducing crystallization time by up to 75% (optimal condition: 60 min). Among various imidazolium-based ionic liquids, [BMMIm]Br demonstrated an optimal balance of hydrophilic and hydrophobic interactions, yielding composite zeolites with high surface area (350 m²·g⁻¹) and large pore volume (0.28 cm³·g⁻¹). Comprehensive characterization (XRD, SEM-EDX, NH₃-TPD) confirmed the formation of well-defined ZSM-5/AlPO₄-5 core–shell structures and revealed tunable acid site distributions depending on the ionic liquid used. In methanol to olefins (MTO) reactions, the composite catalyst exhibited outstanding selectivity towards light olefins (C₂=–C₄=: 72.84%), markedly outperforming the individual ZSM-5 and AlPO₄-5 components. The superior catalytic behavior is primarily attributed to the synergistic effect of hierarchical acid site tuning and the integrated core–shell architecture, which together optimize reaction selectivity. This strategy provides a promising route for the rational design of high-performance zeolites with significant industrial applicability. Full article

The dehydration of methanol to produce light olefins and gasoline, known as MTO (methanol-to-olefins) process requires acidic catalysts that maintain their acidity at reaction temperatures. Zeolites, such as SAPOs and ZSM-5, are commonly used for this purpose due to their acidic centers. The initial step in these experiments involves the activation or pretreatment of these solids to remove physically adsorbed water from their pores. Inadequate pretreatment can lead to the destruction of the existing Brönsted sites through the dihydroxylation of surface -OH groups. Therefore, it is crucial to pretreat the zeolites properly to preserve the Brönsted sites. One method is to subject the fresh catalyst to programmed dehydration, which involves desorption at a controlled temperature while monitoring the appearance of water that results from Brönsted site dihydroxylation. The temperature at which the dehydration peak appears determines the optimal reaction temperature. The results presented in this work will demonstrate the progressive deactivation of the catalysts when the reaction temperature exceeds 400 °C. Full article

The chemical industry is a key driver of economic growth and innovation but remains one of the largest contributors to greenhouse gas (GHG) emissions. Achieving sustainability demands advancements in green chemistry and cleaner production methods. This study investigates emission reduction strategies across Scope 1, Scope 2, and Scope 3 by applying both top-down and bottom-up approaches within four system boundaries. The Austrian chemical sector, with a focus on ammonia, methanol, and olefins, serves as a case study. Results highlight the potential of abatement technologies and alternative feedstocks—such as low-carbon hydrogen and methanol—to significantly reduce emissions. Hydrogen-based production for ammonia and methanol, along with low-carbon methanol in olefin production, could reduce Scope 1 and Scope 2 emissions by approximately 80% compared to conventional methods. However, Scope 3 emissions remain challenging due to embedded carbon in feedstocks and CO₂ use in production, particularly in product use and end-of-life phases. A comprehensive life cycle assessment is crucial to addressing these impacts. To evaluate Scope 3 emissions, this study explores three decarbonization scenarios: the reference scenario—relies on fossil-based production with high emissions; the geogenic scenario—integrates abatement technologies and geogenic CO₂ feedstock, reducing emissions by about 46%; and the bio-based scenario—combines abatement technologies with biogenic CO₂ feedstock, achieving an 80% reduction in total emissions at the national level. The findings emphasize the need for a system-wide approach that integrates bio-based solutions and circular economy strategies to achieve climate neutrality. However, uncertainties in climate policy, bio-resource availability, and data gaps in Scope 3 emissions must be addressed to ensure effective decarbonization and alignment with climate goals. Full article

Commercial ascorbyl-6-O-esters (AEs) are composed of saturated fatty acids with relatively high melting points, resulting in limited solubility in lipophilic media. Therefore, a lipase-catalysed synthesis and purification method for ascorbyl-6-O-oleate (AO) was proposed in this study. The esterification synthesis (i.e., bonding of oleoyl group to ascorbic acid) rate was 19.7% using acetone as the reaction solvent. The transesterification synthesis (i.e., exchange of acyl group with oleic acid (OA) in ascorbyl-6-O-palmitate (AP)) rate increased to 73.8% (AP:OA = 1:3, molar ratio). The esterification product was purified sequentially by liquid–liquid extraction using ethyl acetate and water, followed by hexane and acetonitrile, resulting in 94.8 area% AO confirmed by HPLC. When acetonitrile was replaced with 90% methanol, AO achieved 97.2 area%. Similarly, the transesterification product showed 94.3 area% AEs (AP:AO = 8.9:91.1) after recrystallisation and liquid–liquid extraction. Finally, all purified AO revealed peaks corresponding to the hydroxyl groups at the C-2 and C-3 carbons (11.10 and 8.41 ppm, ¹H-NMR), whereas OA selectively esterified at the C-6 carbon (¹³C-NMR). FT-IR confirmed the presence of the ester bond (1733 cm⁻¹) and olefin structure (3006 cm⁻¹) of OA, and LC-ESI-MS/MS identified AO peaks at m/z 439.3. DSC analysis showed broad endothermic curves at 23.1–46.7 °C when the purified AO samples were pre-cooled at −25 °C. Full article

Small-pore zeolites catalyze the methanol-to-olefins (MTO) reaction via a dual-cycle mechanism, encompassing both olefin- and aromatic-based cycles. Zeolite topology is crucial in determining both the catalytic pathway and the product selectivity of the MTO reaction. Herein, we investigate the mechanistic influence of MCM-35 zeolite on the MTO process. The structural properties of the as-synthesized MCM-35 catalyst, including its confined cages (6.19 Å), were characterized, confirming them as the catalytic centers. Then, the MTO reactions were systematically performed and investigated over a MCM-35 catalyst. Feeding pure methanol to the reactor yielded minimal MTO activity despite the formation of some aromatic species within the zeolite. The results suggest that the aromatic-based cycle is entirely suppressed in MCM-35, preventing the simultaneous occurrence of the olefin-based cycle. However, cofeeding a small amount of propene in methanol can obviously enhance the methanol conversion under the same studied reaction conditions. Thus, the exclusive operation of the olefin-based cycle in the MTO reaction, independent of the aromatic-based cycle, was demonstrated in MCM-35 zeolite. Full article

The separation section of the methanol-to-olefin (MTO) process is energy-intensive, and the optimization and heat integration can enhance energy efficiency and reduce costs. A bi-level optimization model framework is proposed to optimize the separation process and simultaneously integrate the heat exchanger network (HEN). The upper level employs a data-driven BP neural network proxy model instead of the mechanism model for the separation process, while the lower level adopts a stage-wise superstructure for the HEN without stream splits. The interaction between the two systems is realized effectively through information exchange. A bi-level particle swarm algorithm is employed to optimize complex problems and determine the optimal operational parameters for the distillation system and HEN. Compared with the typical sequential synthesis method, the optimization by the proposed approach reduces the total annual cost by $1.4293\times {10}^6$ USD/y, accounting for 4.76%. Full article

During the methanol-to-aromatics (MTA) process, a large amount of water is generated, while the influence and mechanism of water on the activity and selectivity of the light olefin aromatization reaction are still unclear. Therefore, a study was conducted to systematically investigate the effects of water on the reactivity and the product distribution in ethylene aromatization using infrared spectroscopy (IR), intelligent gravitation analyzer (IGA), and X-ray absorption fine structure (XAFS) characterizations. The results demonstrated that the presence of water reduced ethylene conversion and aromatic selectivity while increasing hydrogen selectivity at the same contact time. This indicated that water had an effect on the reaction pathway by promoting the dehydrogenation reaction and suppressing the hydrogen transfer reaction. A detailed analysis using linear combination fitting (LCF) of Zn K-edge X-ray absorption near-edge spectroscopy (XANES) on Zn/HZSM-5 catalysts showed significant variations in the state of existence and the distribution of Zn species on the deactivated catalysts, depending on different reaction atmospheres and water contents. The presence of water strongly hindered the conversion of ZnOH⁺ species, which served as the active centers for the dehydrogenation reaction, to ZnO on the catalyst. As a result, the dehydrogenation activity remained high in the presence of water. This study using IR and IGA techniques revealed that water on the Zn/HZSM-5 catalyst inhibited the adsorption of ethylene on the zeolite, resulting in a noticeable decrease in ethylene conversion and a decrease in aromatic selectivity. These findings contribute to a deeper understanding of the aromatization reaction process and provide data support for the design of efficient aromatization catalysts. Full article

Crystal size is a key parameter of zeolites applied as catalysts. Herein, ZSM-5 crystals with similar physicochemical and acid properties, few defects, and aluminum exclusively in tetrahedral coordination are synthesized and the influence of the crystal size on the MTO and ETA conversion is investigated. Short olefins are the main products of the MTO conversion, whereas larger olefins and aromatics dominate the products after ETA conversion. In the case of both feeds, an increased crystal size decreases the catalyst’s lifetime. The MTO conversion over larger ZSM-5 altered the product distribution, which was not the case for the ETA conversion. The reason is that the instantly available aromatics during ETA conversion lead to fast coking and zeolite crystals only active in the outer layers. Thus, the different reactivity of different-sized ZSM-5 is direct proof of a different conversion mechanism for both alcohols. Full article

Forest wood biomass can be used as a renewable resource for the sustainable production of fuels and chemicals. In this study, the methanol, methanol/ethanol, and ethanol/benzene solvent extracts of Platanus orientalis L. bark were analyzed using FTIR, ^IH NMR, ¹³C NMR, 2D-HSQC NMR, GC-MS, and TOF-LC-MS. The results revealed that the bark of Planus orientalis contained a wide variety of chemical compounds, such as 30-triacontanol, 1-Hexanol, hexadecanoic acid, methyl ester, 2-ethyl-, γ-Sitosterol, and 3,4,5-tri methoxy-Phenol. In addition, the fast pyrolysis of P. orientalis L. bark (POL-B) with nano-catalysts (Co₃O₄, Fe₂O₃, and Co₃O₄/Fe₂O₃) was investigated using pyrolysis/gas chromatography/mass spectrometry (Py-GC/MS) and a thermogravimetric analyzer coupled with an FTIR spectrophotometer (TG-FTIR). The TG results revealed that the nano-catalysts significantly affected the pyrolysis of P. orientalis bark. The nano-Fe₂O₃ catalyst was shown to increase acid and ketone compound production during the catalytic pyrolysis of cellulose. According to the Py-GC-MS results, the pyrolytic products contained several value-added chemicals and high-quality bio-oil. The nano-catalysts promoted the production of aromatics, phenols, ketones, olefins, furans and alkane compounds. These natural-product active molecules and bio-oil, as high-grade raw materials, could be used in many industrial and agricultural fields for the production of wetting agents, stabilizers, plasticizers and resins. In addition, a number of active molecules could be used as drugs and biomedical active ingredients for anti-cancer and anti-inflammatory purposes. Full article