Olefins Process Research Articles

Maximizing Ethylene Production Yield by Modifying the Methanol to Olefin Process with the Addition of a Distillation Tower

Ethylene is a feedstock that produces polyethene and other industrial chemicals such as ethylene oxide. The methanol-to-olefins process is a technology designed to transform methanol into light olefins like ethylene and propylene, which are crucial raw materials in the petrochemical industry. The first reaction involves the production of dimethyl ether and water from methanol. The second reaction consists of the conversion of dimethyl ether to ethylene and water. This paper will explain how to maximize ethylene production yield by modifying the methanol to olefin process. The process modification was carried out by adding a distillation tower. Based on process modifications increased the ethylene quantity from 21,070 tons/year to 179,400 tons/year. The case study results indicate an increasing yield of the product exiting. Copyright © 2024 by Authors, Published by Universitas Diponegoro and BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Gevo obtains patent for its ethanol to olefins (ETO) process

Gevo obtains patent for its ethanol to olefins (ETO) process

Understanding the Level of Integration in Existing Chemical Clusters: Case Study in the Port of Rotterdam

AbstractThe petrochemical industry is composed of several interconnected processes that use fossil-based feedstock for producing chemicals. These processes are typically geographically clustered and often belong to different parties. Reducing the environmental impacts of the petrochemical industry is not straightforward due to, on the one hand, their reliance on fossil fuels for energy and as a feedstock and, on the other hand, the significant level of interconnected energy and material flows among processes. Current methods for analyzing changes to existing processes cannot capture the multitude and level of interactions. The goal of this paper is to create a model of a petrochemical cluster and analyze its physical characteristics and performance. This paper addresses this goal by developing an assessment method that combines process simulations, multiplex graph analysis, and key performance indicators. The method is applied to a case study based on the petrochemical cluster in the Port of Rotterdam, resulting in a uniquely highly detailed model of a petrochemical cluster. The network analysis results show that only some of the processes are very interconnected. From the performance analysis, it can be observed that the olefins process is the most carbon-intense and has high CO2 emissions. Additionally, the results showed the importance of considering existing interconnections when assessing the current performance of existing petrochemical clusters or the performance due to future changes to chemical processes. For instance, some changes would occur to an industrial cluster by introducing alternative carbon sources, such as biomass or CO2.

Effect of pretreatment conditions on a benchmark iron catalyst for CO2 hydrogenation to light olefins

To improve the CO2-to-light olefin process in terms of economics, efficient catalysts are essential to maximize the yield. Our research was carried out on FeAlCuK, which is still considered as a benchmark for olefin formation via CO2 Fischer-Tropsch synthesis (FTS). Nevertheless, the effect of various activation conditions on the formation of desired active species and final activity of this catalyst has not been described in literature to date. We studied the pretreatment by varying both the reduction gas and temperature. The catalyst was pretreated with pure H2 or synthesis gas (H2/CO = 3) to identify the bulk and surface species formed in each case. We demonstrate that the FeCuAlK catalyst should be activated in a H2/CO atmosphere at 250 °C for 4 h before the test at typical FTS reaction conditions to reach maximum productivity. The reduction with H2/CO led to the formation of active Fe5C2 and Fe3O4 phases producing a high fraction of light olefins at higher CO2 conversion. The role of promoters K and Cu was also investigated. Selectivity for desired C2-C4 olefins increased by 10 % compared to catalysts which were used directly in FTS without preliminary activation. Characterization with ex and in situ powder X-ray diffraction, Raman spectroscopy, and XPS after each activation treatment as well as Mössbauer spectroscopy revealed a strong impact of gas nature on the phase composition which was correlated with the performance.

An auto‐configurable machine learning framework to optimize and predict catalysts for CO2 to light olefins process

AbstractThis study proposed an auto‐configurable machine learning framework based on the differential evolution algorithm (AutoML‐DE) driven by hybrid data for the screening and discovery of promising CO2 to light olefins (CO2TLO) catalysts candidates. The hybrid dataset comprises 532 experimental data from the literature and 296 simulation data. Results show that the AutoML‐DE model with extreme gradient boosting algorithms demonstrated superior performance for predicting the conversion ratio of CO2 and selectivity of light olefins (average R2 > 0.86). After identifying the input feature with the most significant impact on the output feature, the optimal AutoML‐DE model integrated with the genetic algorithm is applied to multiobjective optimization, sensitivity analysis, and prediction of new CO2TLO catalysts. The optimized Cu‐Zn‐Al/SAPO‐34 catalyst has the highest catalytic performance among the reported CO2TLO catalysts. Moreover, five new CO2TLO catalysts with higher yields are successfully predicted. However, the performance of these catalysts should be further verified by experiment.

Mechanochemical Assembly of a Nitrile‐Based Directing Group in Arylacetic Acids Using the Passerini 3‐CR: Exploration of the Pd(II)‐Catalyzed meta‐C(sp2)−H Bond Olefination Process

AbstractThe multicomponent assembly of a nitrile‐based directing group in a set of arylacetic acids under solvent‐free mechanochemical conditions using the Passerini 3‐CR and the subsequent Pd(II)‐mediated meta‐C(sp2)−H bond olefination process has been achieved. The protocol demonstrated that removing the DG under mild conditions from the activated Passerini adducts affords a novel N‐(tert‐butyl)‐2‐(2‐cyanophenyl)‐2‐hydroxyacetamide, which can be re‐utilized in the future as DG in other distal activation processes.

Improvement of catalyst activity in cracking of n-hexane via metal (Fe/Ga) impregnation over ZSM-12 catalyst

In this research, zeolite ZSM-12 with Si/Al ratio = 80 was synthesized by hydrothermal method. The synthesized zeolite ZSM-12 was modified using Fe and Ga metals and a combination of these two metals, 1 % iron metals (Z80-Fe) and 1 % gallium metals(Z80-Ga), and a 2 % combination of these two metals (Z80-Fe-Ga). The physicochemical properties of synthesized zeolites were evaluated and compared by XRD, EDX-dot-mapping, NH3-TPD, BET, FT-IR, and TGA analyses. The catalytic assessment of synthesized zeolites in the HTO (n-hexane to olefins) process in a fixed bed reactor under atmospheric pressure and Weight hourly space velocity (WHSV) equal to 4 h−1 at 550 °C was evaluated. Various parameters such as selectivity towards light olefins, propylene to ethylene (P/E ratio), production of light alkanes, and aromatic compounds (BTX) were investigated. The results show that using metals led to the improvement and adjustment of the acid sites of zeolite, and the highest amount of light olefin and the lowest amount of coke were obtained. The result of the n-hexane to olefin process showed that the yield of light olefins was significantly improved in all modified catalysts compared to parent zeolite MTW. Compared to other modified zeolites, Z80-Fe-Ga zeolite has the highest yield of light olefins, equal to 59 %. This zeolite performs better due to the presence of gallium and iron metals and shows the highest propylene selectivity (P/E = 2.4). In addition, according to the results of the TGA analysis, the content of coke on the Z80-Fe-Ga catalyst after the catalytic reaction is much less than that of other catalysts after the catalytic reactor test.

An Overview of Julia-lythgoe Olefination.

Julia-Lythgoe olefination (or simply Julia olefination) is an olefination process between phenyl sulfones and aldehydes (or ketones) to give alkenes after alcohol functionalization and reductive elimination using sodium amalgam or SmI2. It is mainly used to synthesize E-alkenes and is a key step in numerous total syntheses of many natural products. This review exclusively deals with the Julia-Lythgoe olefination and concentrates mainly on the applications of this reaction in natural product synthesis covering literature up to 2021.

Tailoring the acidity of ZSM-5 via surface passivation: Catalytic assessment on dimethyl ether to olefins (DTO) process

In the present study, four different samples having different acidity were synthesized. Two MFI-type zeolites having silicon-to-aluminum ratio equal to 25 and 50 were prepared. Besides, two additional samples were obtained by external passivation of each parent zeolite with a layer of Silicalite-1, leading to a core–shell structure. Each sample was characterized to assess textural properties, structure, composition, and acidity, and then tested for dimethyl ether (DME) conversion at different reaction temperatures between 300 and 375 °C. The analysis of produced mixture revealed the simultaneous presence of hydrocarbons and methanol. DME conversion grew by increasing the temperature. Propylene was the most abundant hydrocarbon detected during all the time-on-stream analyses. Especially at 375 °C, the investigated samples having greater acidity showed faster deactivation due to coking. Samples with lower acidity were thus more stable but, on the other hand, they presented higher methanol selectivity and lower hydrocarbons yield.

A versatile electrospinning method to fabricate ZSM-5-decorated MgO nanofibers as a catalyst for methanol to light olefins: Toward remarkable stability and superior performance

In response to the increasing concerns about climate change and the depletion of fossil fuel reserves, the application of zeolite ZSM-5 as a catalyst in the methanol to olefin (MTO) process is considered a promising chemical technique. It holds the potential to produce essential chemical building blocks, such as light olefins, using sustainable raw materials. In this study, electrospun MgO/ZSM-5 nanofibers were synthesized to enhance mass/heat transfer limits during the MTO process and improve catalyst stability. In this synthesis, ZSM-5 nanoparticles with a mean diameter of 600 nm were arranged on magnesium oxide nanofibers with a mean diameter of 200 nm. The catalysts were characterized using various techniques, including XRD, SEM, TEM, EDX-Mapping, NH3-TPD, BET, and TGA. The electrospinning technique prevented nanoparticle accumulation and improved the morphology of the catalyst. In an isothermal fixed-bed reactor, the catalysts were tested at 450 °C, 1 atm, WHSV = 4.5 hr−1, with a methanol-water solution in a 1:1 (v/v) ratio as the feed. The stability of the nanofibers was found to be enhanced compared to ZSM-5 nanoparticles. MgO/ZSM-5-50 nanofibers (50 wt% zeolite), MgO/ZSM-5-80 nanofibers (80 wt% zeolite), and ZSM-5 nanoparticles exhibited methanol conversion rates of 99 %, 88 %, and 76 %, respectively, after 430 min of continuous operation. Furthermore, the amount of coke formed after 10 h for MgO/ZSM-5-50, MgO/ZSM-5-80, and ZSM-5 was 11.83 wt%, 13.63 wt%, and 20.98 wt%, respectively. The reduced coke formation on the electrospun samples compared to ZSM-5 nanoparticles demonstrates improved performance and stability for nanofiber catalysts.

Catalytic pyrolysis of straight-run light oil to light olefins: Role of molecular structure and catalytic materials

The development of straight-run light oil catalytic pyrolysis to light olefins process is an important approach of achieving the transformation and upgrading of the current oil refining industry. However, the industrialization of the catalytic pyrolysis process for straight-run light oil has been slow. Herein, we investigated the decomposition of complex straight-run light oil into different structural units and further examined their effects on light olefins production. The results indicated that the yields of light olefins cracked over MFI zeolite were about 45 % and 30 % for alkane structure and cycloalkane ring structure, respectively. Further analysis showed that the olefin structure could theoretically be cracked to 100 % light olefins, but in fact, 40 % of the light olefins were lost due to the transfer of 10 % hydrogen. Subsequently, the effects of zeolite topology and acid properties on the cracking of different structural units were further analyzed. It was found that zeolites with MTT and MFI topologies contributed to the catalytic pyrolysis of chain and cycloalkane ring structures, respectively, because appropriate pore size helped diffusion of hydrocarbon molecules and inhibited side reactions such as hydrogen transfer. Compared with MFI zeolite, the light olefins yield produced by chain structure cracking over MTT zeolite increased by 5.83 %-10.54 %. In addition, it was discovered that zeolites with total and strong acids in the range of 0.2–0.4 mmol/g and 0.1–0.2 mmol/g, respectively, were beneficial for the cracking of light alkanes in straight-run light oils to light olefins. This work provides useful insights into the fundamental understanding and development of straight-run light oil catalytic pyrolysis to light olefins process.

A knowledge-driven approach for automatic generation of reaction networks of methanol-to-olefins process

In recent years, automatic generation of reaction networks for chemical processes has attracted considerable attention. However, most of the automatic generators focused on the construction of reaction networks by computer and are essentially dependent upon the predefined reaction rules or categories. The reaction rules for constructing reaction networks are derived manually based on the individual’s understanding of reaction mechanism equation as well as the corresponding experiences, which hinders the automatic generation of reaction network directly from the complex reaction mechanisms or equations. In this article, we proposed a strategy to automatically identifies the reaction rules directly from the reaction equation using a Reaction Rules Topological Matrix Representation (RTMR) method. Taking the induction period of methanol to olefins (MTO) process as an example, we showed how to use RTMR to extract the information of reaction mechanism equation in the literatures, and then establish the reaction networks of the multiphase catalytic process. The results suggest that RTMR not only provides an effective approach for automatic reaction mechanisms equation extraction, but also demonstrates new reactions prediction ability after training with the literature information. It is expected RTMR can be promisingly implemented in knowledge-driven reaction network generation in multiphase catalytic processes.

Design and fabrication of the alumina nanofibers decorated with isolated ZSM-5 using electrospinning method: A novel catalyst for methanol conversion to light olefins

ZSM-5 nanoparticles are widely used as the catalyst in the methanol conversion to olefins (MTO) process due to their high surface area and short diffusion path length. However, agglomerate formation is a challenge for this catalyst. To address this issue, in this study, electrospinning was used for the first time to synthesize fibrous catalysts comprised of ZSM-5 nanoparticles embedded in the alumina nanofibers. The catalysts were characterized using XRD, FTIR, SEM, TEM, EDX-map, BET, and NH3-TPD analyses. In the synthesized samples, ZSM-5 nanoparticles with an average particle size of 683 nm are uniformly and homogeneously dispersed over alumina nanofibers with a 300 nm diameter. These composites form core-shell structures and have a reactor porosity of 0.85, which is higher than that of parent ZSM-5. In the MTO process, electrospun catalysts demonstrate superior catalytic activity and a longer lifespan than powder catalysts. 80 wt% ZSM-5- 20 wt% Al2O3 with 47.76 % light olefin selectivity and complete methanol conversion after 321min on stream performed better than 50 wt% ZSM-5-50 wt% Al2O3. Moreover, a lower coke formation of about 3.28 % was achieved for the 80 wt% ZSM-5- 20 wt% Al2O3 sample. The reduced bulk density of the electrospun samples increases the probability of reactant and catalyst contact. Additionally, electrospinning is an effective method for reducing particle aggregation and improving catalytic process efficiency.

Lewis Acid-Promoted [2 + 2] Cycloadditions of Allenes and Ketenes: Versatile Methods for Natural Product Synthesis.

ConspectusCycloaddition reactions are an effective method to quickly build molecular complexity. As predicted by the Woodward-Hoffmann rules, concerted cycloadditions with alkenes allow for the constructions of all possible stereoisomers of product by use of either the Z or E geometry. While this feature of cycloadditions is widely used in, for example, [4 + 2] cycloadditions, translation to [2 + 2] cycloadditions is challenging because of the often stepwise and therefore stereoconvergent nature of these processes. Over the past decade, our lab has explored Lewis acid-promoted [2 + 2] cycloadditions of electron-deficient allenes or ketenes with alkenes. The concerted, asynchronous cycloadditions allow for the synthesis of various cyclobutanes with control of stereochemistry.Our lab developed the first examples of Lewis acid-promoted ketene-alkene [2 + 2] cycloadditions. Compared with traditional thermal conditions, Lewis acid-promoted conditions have several advantages, such as increased reactivity, increased yield, improved diastereoselectivity, and, for certain cases, inverse diastereoselectivity. Detailed mechanistic studies revealed that the diastereoselectivity was controlled by the size of the substituent and the barrier of a deconjugation event. However, these reactions required the use of stoichiometric amounts of EtAlCl2 because of the product inhibition, which led us to investigate catalytic enantioselective [2 + 2] cycloadditions of allenoates with alkenes. Through the use of chiral oxazaborolidines, a broad range of cyclobutanes can be prepared with the control of enantioselectivity. Mechanistic experiments, including 2D-labled alkenes and Hammett analysis, illuminate likely transition state models for the cycloadditions. Additional studies led to the development of Lewis acid-catalyzed intramolecular stereoselective [2 + 2] cycloadditions of chiral allenic ketones/esters with alkenes.The methods we developed have been instrumental in the synthesis of several families of natural products. Specifically, one key lactone motif in (±)-gracilioether F was constructed by a ketene-alkene [2 + 2] cycloaddition and subsequent regioselective Baeyer-Villiger oxidation sequence. Enantioselective allenoate-alkene [2 + 2] cycloadditions allowed for the synthesis of (-)-hebelophyllene E. Another attempt of applying this method in the synthesis of (+)-[5]-ladderanoic acid failed to deliver the desired cyclobutane because of an unexpected rearrangement. The key cyclobutane was later assembled by a stepwise carboboration/Zweifel olefination process. Finally, the stereoselective [2 + 2] cycloadditions of allenic ketones and alkenes was applied in the syntheses of (-)-[3]-ladderanol, (+)-hippolide J, and (-)-cajanusine.

A facile strategy to prepare ZSM-5-based composites with enhanced light olefin selectivity and stability in the HTO process.

In this study, the influence of different ZSM-5 composite materials (ASA, γ-alumina, η-Al2O3, SiO2, and attapulgite) and their performance in the n-hexane catalytic cracking process in a fixed bed microreactor at 550 °C under atmospheric pressure was studied. XRD, FT-IR spectroscopy, NH3-TPD, BET, FE-SEM, and TG analyses were performed to characterize the catalysts. The result of the n-hexane to olefin process indicated that the A2 catalyst (γ-alumina composition with ZSM-5) showed the highest conversion of 98.89%, highest propylene selectivity of 68.92%, highest yield of light olefins of 83.84%, and highest propylene to ethylene ratio of 4.34. The reason for the significant increase in all these factors and the lowest amount of coke in this catalyst is the use of γ-alumina, which increased the hydrothermal stability and resistance to deactivation, improved the acidic properties with a strong to weak acid ratio of 0.382, and increased the mesoporosity to 0.242. This study indicates the effect of the extrusion process and the composition and the major effect of the properties of this material on the physicochemical properties and distribution of the product.

Effect of CNT over structural properties of SAPO-34 in MTO process: Experimental and molecular simulation studies

The hierarchical silicoaluminophosphate (SAPO-34) catalyst was synthesized using the mixtures of diethylamine (D) and butylamine (B) as a structure-directing agent (SDA), and carbon nanotube (CNT) as a secondary template in the hydrothermal method. The catalysts were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), N2 physisorption, and temperature-programmed desorption of ammonia (NH3-TPD) techniques and evaluated for the catalytic activity in the Methanol to Olefins (MTO) process. The results showed that the use of CNT as the secondary template improved the hierarchical structure of SAPO-34 due to increasing the external surface area and mesoporosity and decreasing the particle size and as a result, made better the performance of the prepared SAPO-34 zeolite in the MTO process. Among all the prepared samples, the CNT-B-D catalyst synthesized by mixing three templates displayed the highest ethylene and propylene selectivity of 49% and 34%, respectively. Also, using CNT in the synthesis of samples increased the catalytic stability. In addition, pure, binary, and ternary adsorption isotherms and diffusivities of the main products and reactants over the SAPO-34 were investigated by theoretical measurements, because sorption and diffusion affect the catalyst stability and C2–C3 selectivity in the MTO reaction. The higher diffusion rate of ethylene leads to following the aromatic-based cycle in the MTO process.

A Simultaneous Design and Optimization Framework for the Reaction and Distillation Sections of Methanol to Olefins Process

The reaction and separation sections are the keys to the methanol-to-olefins (MTO) chemical processes, and they should be optimized to reduce the cost of production. This work develops a framework for the simultaneous design and optimization of the reaction and distillation sections. An optimization model with shortcut and rigorous methods combined is established for distillation columns to improve accuracy and efficiency. With the auxiliary devices and the selection of utilities considered, the reaction and distillation sections are integrated to maximize profits. The genetic algorithm targets the optimal parameters, including the catalyst’s coke content and reaction temperature, each column’s operating pressure, and the allocation of utilities and auxiliary devices. For the studied MTO process, the optimal reaction temperature and catalyst’s coke content were identified to be 496 °C and 7.8%, respectively. The maximum profit is 15.3% greater than that identified with only the separation section optimized, and the minimum total annual cost (TAC) of the separation section is 3.73% less.

Optimization Modeling for Advanced Syngas to Olefin Reactive Systems

Reactor designs with mixed catalysts play an important role in transforming a multiple reactor system to single-shot reactors. In addition to savings in capital and ease of implementation, single-shot reactors are useful to break equilibrium limitations, thereby increasing the yield and selectivity of desired product as shown in previous studies. However, the nonlinear and highly exothermic nature of mixed-catalyst systems makes it difficult for commercial process simulation and optimization tools to optimize these systems. This study describes the development and application of optimization strategies for mixed-catalyst, single-shot reactors for syngas to olefin (STO) processes. Finding the optimal catalyst distribution is challenging and requires advanced solution strategies for singular optimal control problems, which are poorly conditioned and often lead to flat response surfaces. The graded bed and partial-moving finite-element approaches are used to find the optimal catalyst distribution that maximizes the olefins yield. A 1.3% increase in the yield is observed from one zone to three zones. The yield further improves from three zones to the exact infinite dimensional solution by 0.2%. This improvement can be realized in practice by changing only the catalyst distribution, without any extra investment. Finally, the results suggest that a mixed-catalyst single shot reactor bed can be applied to other reaction mechanisms to increase reactor performance.

Effects of zeolite morphologies on CO conversion to aromatics via a modified Fischer‐Tropsch synthesis pathway

AbstractBACKGROUNDSyngas conversion to olefins via Fischer‐Tropsch Synthesis (FTs) route and then subsequently into aromatics (syngas−olefins−aromatics (SOA)) was considered a promising industrialization route due to its ability to match reaction temperatures between syngas to olefins (300–400 °C) and olefins to aromatics (300–500 °C). In this reaction route, the syngas to olefin process can be efficiently and easily realized by Fe‐based FTs catalysts. However, the aromatization process occurring over the zeolite catalyst was still considered a big challenge due to zeolites' complex topology, variable morphology, and elusive acidic properties.RESULTSA series of ZSM‐5 zeolites with different morphologies, including nano ellipsoid, nano cube, nano aggregate, nano bead, and nano pile were successfully synthesized . The effects of the ZSM‐5 zeolite's morphology and reaction temperature on the aromatics synthesis from syngas based on a modified FTs route were systematically studied.CONCLUSIONIn all the studied ZSM‐5 zeolites, the nano cube ZSM‐5 zeolite (Z5‐NC) zeolite had the best aromatization ability. The hybrid catalyst combination of FeMnK&Z5‐NC obtained the highest xylene selectivity of 12% (2.8% + 9.2%), and its total aromatics selectivity was also the highest (42.5%). The study on reaction temperature suggested that a higher reaction temperature (320–360 °C) could efficiently impede the formation of CO2. However, the selectivity of aromatics was restrained to around 44% at higher temperatures because a high temperature facilitated the hydrocracking of higher hydrocarbons, leading to the increase of the selectivity of lighter CH4 and paraffin. © 2022 Society of Chemical Industry (SCI).

Theoretical and experimental insights into CO2 formation on Co2C catalysts in syngas conversion to Value-Added chemicals

Cobalt carbide (Co2C) has been discovered as the promising active phase for Fischer–Tropsch to olefins (FTO) process and higher alcohols synthesis (HAS) from syngas, in the form of nanoprisms and nanospheres, respectively. However, CO2 formation is inevitable on Co2C catalysts, especially in FTO process. So far, the mechanism of CO2 formation on Co2C surfaces is less understood. This work provides fundamental insights into CO2 formation on Co2C nanospheres and nanoprisms through computational and experimental study. DFT calculations demonstrate that: Co2C (101) and (020) surfaces exposed on Co2C nanoprisms are basically not active for water gas shift (WGS) reactions but the introduction of Na greatly promotes CO2 formation. CO2 is less favored on Co2C(111) surface which is dominant on Co2C nanospheres, however, the reverse WGS activities can be promoted with Na addition. The experimental results confirmed removing Na from Co2C can efficiently suppress WGS activity, thus reducing CO2 selectivity while the selectivity of light olefins retained. Though previous studies focused on Na addition to promote the yield of light olefins, our work indicates that Na also promotes undesired CO2 formation. Our results suggest that Na is crucial for active phase formation but not necessarily beneficial during the CO hydrogenation reactions.