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Records with Keyword: Dimethyl Ether
Experimental Study of Nucleate Boiling of Flammable, Environmentally Friendly Refrigerants
Bartosz Gil, Beata Fijałkowska
March 22, 2023 (v1)
Subject: Environment
Keywords: alternative refrigerants, Dimethyl Ether, hydrocarbons, low global warming potential (GWP), pool boiling, RE170
This paper investigates the nucleate boiling process of dimethyl ether and selected hydrocarbons. The main goal of this study is to measure the heat transfer coefficients of RE170, R600a, and R601, and to compare them with R134a. The experiments were carried out for heat fluxes up to 70 kW/m2. Experimental results have shown a typical trend that the heat transfer coefficient of flammable refrigerants increases as the heat flux increases. Among the tested fluids, the highest values of heat transfer coefficient were obtained for RE170. Available correlations describing this coefficient showed a deviation of up to 93%, as compared to the data obtained. The new correlation was developed by regression analysis taking into account dimensionless variables affecting the boiling process.
Probing the Pre-Ignition Behavior of Negative Temperature Coefficient Fuels at Low to High Temperatures: A Case Study of Dimethyl Ether
Wenlin Huang, Honghuan Wu, Wuchuan Sun, Congjie Hong, Zemin Tian, Yingwen Yan, Zuohua Huang, Yingjia Zhang
March 17, 2023 (v1)
Keywords: Dimethyl Ether, NTC fuels, physical-based criteria, pre-ignition
Pre-ignition, involving complex interactions of physical and chemical processes, occurs not only in actual combustion engines but also in fundamental research equipment such as rapid compression machines and shock tubes. Thus, identifying the combustion conditions prone to pre-ignition is critical for the interpretation of ignition data and fuel design. Shock tube experiments with dimethyl ether (DME) were carried out in this study to investigate the pre-ignition behavior during fuel auto-ignition. The experimental conditions included a wide range of temperatures (620−1370 K), pressures (1−9 atm), and equivalence ratios (0.5−5.0). The results indicate that pre-ignition of DME is prone to occur in the transition region from a high temperature to an intermediate temperature (~1000 K), and the decrease in pressure and equivalency ratio will aggravate the pre-ignition behavior. Theoretical analysis was then performed using four physical-based criteria: temperature perturbation sensitivity... [more]
Influence of LPG and DME Composition on Spark Ignition Engine Performance
Paweł Fabiś, Bartosz Flekiewicz
March 10, 2023 (v1)
Keywords: Dimethyl Ether, gaseous fuels, LPG, LPG–DME mixture
This article presents a detailed analysis of the potential of dimethyl ether (DME) fuel applications in SI engines. This paper presents the tests results completed on an 1.6-dm3 Opel Astra engine fueled by gaseous fuel as a mixture of LPG and DME. Dimethyl ether is a fuel with properties similar to liquid LPG fuel. In addition, DME is very well miscible with LPG, hence the possibility of creating a mixture with any DME divisions. The assessment of the possibility of using DME as a component of the mixture was carried out with the use of a chassis dynamometer and equipment, enabling an analysis of the changes taking place inside the cylinder. The results of the analyses are the parameters of the thermodynamic processes describing changes in the engine cylinder.
Combustion Performance and Low NOx Emissions of a Dimethyl Ether Compression-Ignition Engine at High Injection Pressure and High Exhaust Gas Recirculation Rate
Inmo Youn, Joonho Jeon
March 2, 2023 (v1)
Keywords: combustion process, Dimethyl Ether, exhaust gas recirculation, nitrogen oxides
Dimethyl ether (DME) is a promising alternative to diesel for compression-ignition (CI) engines used in various industrial applications. However, the high nitrogen oxide (NOx) emissions of DME combustion have restricted its use. The primary cause of high NOx emissions is a high combustion temperature. In this study, a high exhaust gas recirculation (EGR) rate was used when testing a common-rail direct injection CI engine suitable (with minor modifications) for a passenger car. A modified fuel supply system created high injection pressure during evaluation of combustion performance. The physical and chemical properties of DME were the principal determinants of the ignition delay, combustion speed, and heat release rate. Although a high injection pressure accelerated formation of the fuel-air mixture and the combustion speed, combustion performance deteriorated with increased NOx emissions. An increased EGR rate affected combustion and the NOx concentration. A high EGR rate effectively r... [more]
Study on Chemical Kinetics Mechanism of Ignition Characteristics of Dimethyl Ether Blended with Small Molecular Alkanes
Kai Niu, Baofeng Yao, Yonghong Xu, Hongguang Zhang, Zhicheng Shi, Yan Wang
February 28, 2023 (v1)
Keywords: Dimethyl Ether, high pressure, ignition delay, low temperature, multi-stage ignition, small molecule alkane
Dimethyl ether (DME)/C1-C4 alkane mixtures are ideal fuel for homogeneous charge compression ignition (HCCI) engines. The comparison of ignition delay and multi-stage ignition for DME/C1-C4 alkane mixtures can provide theoretical guidance for expanding the load range and controlling the ignition time of DME HCCI engines. However, the interaction mechanism between DME and C1-C4 alkane under engine relevant high-pressure and low-temperature conditions remains to be revealed, especially the comprehensive comparison of the negative temperature coefficient (NTC) and multi-stage ignition characteristic. Therefore, the CHEMKIN-PRO software is used to calculate the ignition delay process of DME/C1-C4 alkane mixtures (50%/50%) at different compressed temperatures (600−2000 K), pressures (20−50 bar), and equivalence ratios (0.5−2.0) and the multi-stage ignition process of DME/C1-C4 alkane mixtures (50%/50%) over the temperature of 650 K, pressure of 20 bar, and equivalence ratio range of 0.3−0.5... [more]
Recent Progress on Hydrogen Storage and Production Using Chemical Hydrogen Carriers
Ewelina Pawelczyk, Natalia Łukasik, Izabela Wysocka, Andrzej Rogala, Jacek Gębicki
February 27, 2023 (v1)
Subject: Environment
Keywords: chemical storage, dibenzyltoluene, Dimethyl Ether, hydrogen storage, Methanol, organic hydrogen carriers
Depleting fossil fuel resources and anthropogenic climate changes are the reasons for the intensive development of new, sustainable technologies based on renewable energy sources. One of the most promising strategies is the utilization of hydrogen as an energy vector. However, the limiting issue for large-scale commercialization of hydrogen technologies is a safe, efficient, and economical method of gas storage. In industrial practice, hydrogen compression and liquefaction are currently applied; however, due to the required high pressure (30−70 MPa) and low temperature (−253 °C), both these methods are intensively energy consuming. Chemical hydrogen storage is a promising alternative as it offers safe storage of hydrogen-rich compounds under ambient conditions. Although many compounds serving as hydrogen carriers are considered, some of them do not have realistic perspectives for large-scale commercialization. In this review, the three most technologically advanced hydrogen carriers—di... [more]
A Review on Deactivation and Regeneration of Catalysts for Dimethyl Ether Synthesis
Joanna Sobczak, Izabela Wysocka, Stanisław Murgrabia, Andrzej Rogala
February 27, 2023 (v1)
Keywords: catalysts, deactivation, Dimethyl Ether, regeneration
The deactivation of catalysts and their regeneration are two very important challenges that need to be addressed for many industrial processes. The most quoted reasons for the deterioration of dimethyl ether synthesis (DME) concern the sintering and the hydrothermal leaching of copper particles, their migration to acid sites, the partial formation of copper and zinc hydroxycarbonates, the formation of carbon deposits, and surface contamination with undesirable compounds present in syngas. This review summarises recent findings in the field of DME catalyst deactivation and regeneration. The most-used catalysts, their modifications, along with a comparison of the basic parameters, deactivation approaches, and regeneration methods are presented.
The Environmental Impacts of Carbon Capture Utilization and Storage on the Electricity Sector: A Life Cycle Assessment Comparison between Italy and Poland
Marco Facchino, Paulina Popielak, Marcin Panowski, Dariusz Wawrzyńczak, Izabela Majchrzak-Kucęba, Marcello De Falco
February 27, 2023 (v1)
Subject: Environment
Keywords: CCS, CCU, Dimethyl Ether, life cycle assessment
Carbon Capture Utilization and Storage (CCUS) is a set of technologies aimed at capturing carbon dioxide (CO2) emissions from point-source emitters to either store permanently or use as a feedstock to produce chemicals and fuels. In this paper, the potential benefits of CCUS integration into the energy supply sector are evaluated from a Life Cycle Assessment (LCA) perspective by comparing two different routes for the CO2 captured from a natural gas combined cycle (NGCC). Both the complete storage of the captured CO2 and its partial utilization to produce dimethyl ether are investigated. Moreover, the assessment is performed considering the region-specific features of two of the largest CO2 emitters in Europe, namely Italy and Poland. Results shows that the complete storage of the captured CO2 reduces Global Warming Potential (GWP) by ~89% in Italy and ~97%, in Poland. On the other hand, the partial utilization of CO2 to produce dimethyl ether leads to a decrease of ~58% in Italy and ~6... [more]
The Influence of LPG and DME Mixtures on Passenger Car Performance
Paweł Fabiś, Marek Flekiewicz
February 27, 2023 (v1)
Keywords: Dimethyl Ether, gaseous fuels, LPG, LPG–DME mixture, performance
The paper presented the dynamics of a vehicle fueled by hybrid fuel, i.e., LPG−DME mixture. The basis for the assessment was the T-ω characteristics of the SI engine with a capacity of 1.6 dm3, determined by the authors for several selected loads and DME mass shares in the engine supply mixture. The analysis and comparison of the impact of the composition of the LPG−DME mixture on the dynamic properties were carried out for the passenger car OPEL Astra, powered by an engine for which T- ω characteristics were determined earlier on the test bench. It has been shown that the mass share of DME in the LPG−DME mixture does not significantly reduce the dynamic index of the car. In addition, the scope of changes in the mass fraction of DME in the mixture was also determined, which will ensure the vehicle performance similar to the power and torque parameters obtained for an engine powered solely by LPG. The received results have made it possible to determine changes in the value of the maximu... [more]
Hydrogen Production System through Dimethyl Ether Autothermal Reforming, Based on Model Predictive Control
Tie-Qing Zhang, Seunghun Jung, Young-Bae Kim
February 24, 2023 (v1)
Keywords: autothermal reforming, Dimethyl Ether, hydrogen production, Model Predictive Control, temperature control
In this study, a thermodynamic analysis of the low temperature autothermal reforming (ATR) of dimethyl ether (DME) for hydrogen production was conducted. The Pd/Zn/γ-Al2O3 catalyst coated on the honeycomb cordierite ceramic was applied to catalyze the reaction, and the optimum activity temperature of this catalyst was demonstrated experimentally and through simulations to be 400 °C. Furthermore, an optimal model predictive control (MPC) strategy was designed to control the hydrogen production rate and the catalyst temperature. Experimental and simulation results indicated that the controller was automated and continuously reliable in the hydrogen production system. By establishing the state-space equations of the autothermal reformer, it can precisely control the feed rates of DME, high-purity air and deionized water. Ultimately, the hydrogen production rate can be precisely controlled when the demand curve changed from 0.09 to 0.23 mol/min, while the catalyst temperature was maintaine... [more]
Optimal Design of a Distillation System for the Flexible Polygeneration of Dimethyl Ether and Methanol Under Uncertainty
Thomas A Adams II, Tokiso Thatho, Matthew C Le Feuvre, Christopher LE Swartz
October 22, 2019 (v2)
Keywords: Dimethyl Ether, Distillation, Flexible polygeneration, Methanol, Optimization, Polygeneration, Process Design Under Uncertainty
This presentation concerns the promising new area of flexible polygeneration, a chemical process design concept in which a chemical plant is able to change its product outputs throughout its lifetime in response to changing market conditions, business objectives, or other external factors. In this talk we present a new flexible polygeneration process system that can switch between dimethyl ether (DME) or methanol production, depending on need. Classic flexible polygeneration systems typically utilize separate process trains for each product, in which whole process trains are turned on or off (or up or down) depending on the current product. However, our proposed process combines the two process trains into one, in which most of the process equipment is always used during either mode of production, but with different operating conditions. In this work, we show how this significantly reduces capital expenditure, reduces the plant footprint, and ultimately is more economical than a tradit... [more]
Techno-economic and environmental analyses of a novel, sustainable process for production of liquid fuels using helium heat transfer
Leila Hoseinzade, Thomas A Adams II
September 26, 2019 (v2)
Keywords: Biomass, Carbonless heat, Dimethyl Ether, Fischer-Tropsch Synthesis, Gasification, Methane Reforming, Negative emissions
In this paper, several new processes are proposed which co-generate electricity and liquid fuels (such as diesel, gasoline, or dimethyl ether) from biomass, natural gas and heat from a high temperature gas-cooled reactor. This carbonless heat provides the required energy to drive an endothermic steam methane reforming process, which yields H2-rich syngas (H2/CO > 6) with lower greenhouse gas emissions than traditional steam methane reforming processes. Since downstream Fischer-Tropsch, methanol, or dimethyl ether synthesis processes require an H2/CO ratio of around 2, biomass gasification is integrated into the process. Biomass-derived syngas is sufficiently H2-lean such that blending it with the steam methane reforming derived syngas yields a syngas of the appropriate H2/CO ratio of around 2. In a prior work, we also demonstrated that integrating carbonless heat with combined steam and CO2 reforming of methane is a promising option to produce a syngas with proper H2/CO ratio for Fisch... [more]
A novel sustainable design for production of liquid fuels
Leila Hoseinzade, Thomas A Adams II
October 30, 2018 (v1)
In this study, a novel biomass-gas-and-nuclear-to-liquids (BGNTL) process is proposed. In this process, nuclear heat is used as the heat source of a steam methane reforming (SMR) process. In a prior work, a rigorous model was developed for the integrated nuclear heat and steam methane reforming process in the gPROMS software package. This model was applied to simulate the integrated nuclear heat and SMR section of BGNTL in Aspen Plus within the other process sections. The BGNTL process was considered for producing different fuels including gasoline & diesel or dimethyl ether (DME). Carbon capture and sequestration (CCS) is considered as an optional section. The performance of the BGNTL process was compared against a non-nuclear process called biomass-and-gas-to-liquids (BGTL). The efficiency, economics, and environmental impact analyses show that the BGNTL process to produce DME is the most efficient, economic and environmentally friendly process among the considered designs. As a resu... [more]
Aspen Plus Simulation of Biomass-Gas-and-Nuclear-To-Liquids (BGNTL) Processes (Using CuCl Route)
James Alexander Scott, Thomas Alan Adams II
August 7, 2018 (v1)
These are Aspen Plus simulation files for a Biomass-Gas-and-Nuclear-To-Liquids chemical plant (a conceptional design), which uses the Copper-Chloride route for hydrogen production. This is a part of a larger work (see linked LAPSE record for pre-print and associated publication in Canadian J Chem Eng). Process sections and major units in this simulation include: Gasification, Integrated-Gasification-Methane-Reforming, Pre-Reforming, Water Gas Shift, Autothermal Reforming, Syngas Blending and Upgrading, Solid Oxide Fuel Cell power islands, Fischer-Tropsch Synthesis, Methanol Synthesis, Dimethyl Ether Synthesis, Heat Recovery and Steam Generation, CO2 Compression for Sequestration, Cooling Towers, and various auxiliary units for heat and pressure management. See the linked work for a detailed description of the model.
Space-constrained purification of dimethyl ether through process intensification using semicontinuous dividing wall columns
Sarah E. Ballinger, Thomas A. Adams II
June 12, 2018 (v1)
Keywords: Aspen Plus, Dimethyl Ether, Dividing wall column, Mobile Plant, Plant-on-a-truck, Process Intensification, Semicontinuous Distillation, Simulation
In this work, a distillation system is designed to purify dimethyl ether (DME) from its reaction by-products in the conversion of flare gas into a useful energy product. The distillation equipment has a size constraint for easy transportation, making process intensification the best strategy to efficiently separate the mixture. The process intensification distillation techniques explored include the dividing wall column (DWC) and a novel semicontinuous dividing wall column (S-DWC). The DWC and the S-DWC both purify DME to fuel grade purity along with producing high purity waste streams. An economic comparison is made between the two systems. The DWC is a cheaper method of producing DME however the purity of methanol, a reaction intermediate, is not as high as the S-DWC. Overall, this research shows that it is possible to purify DME and its reaction by-products in a 40-foot distillation column at a cost that is competitive with Diesel.
The Optimal Design of a Distillation System for the Flexible Polygeneration of Dimethyl Ether and Methanol Under Uncertainty
Thomas A. Adams II, Tokiso Thatho, Matthew C. Le Feuvre, Christopher L.E. Swartz
June 12, 2018 (v1)
Two process designs for the separation section of a flexible dimethyl ether and methanol polygeneration plant are presented, as well as an optimization method which can determine the optimal design under market uncertainty quickly and to global optimality without loss of model fidelity. The polygeneration plant produces a product mixture that is either mostly dimethyl ether or mostly methanol depending on market conditions by using a classic two-stage dimethyl ether production catalytic reaction route in which the second stage is bypassed when the market demand is such that methanol production is more favorable than dimethyl ether. The downstream distillation sequence is designed to purify the products to desired specifications despite the wide variability in feed condition that corresponds to the upstream reaction system operating either in DME-rich or methanol-rich mode. Because the optimal design depends on uncertain market conditions (realized as the percentage of the time in which... [more]
Biomass-Gas-and-Nuclear-To-Liquids Aspen Plus Simulations
Leila Hoseinzade, Thomas A. Adams II
December 7, 2018 (v2)
In this paper, several new processes are proposed which co-generate electricity and liquid fuels (such as diesel, gasoline, or dimethyl ether) from biomass, natural gas and heat from a high temperature gas-cooled reactor. This carbonless heat provides the required energy to drive an endothermic steam methane reforming process, which yields H2-rich syngas (H2/CO>6) with lower greenhouse gas emissions than traditional steam methane reforming processes. Since downstream Fischer-Tropsch, methanol, or dimethyl ether synthesis processes require an H2/CO ratio of around 2, biomass gasification is integrated into the process. Biomass-derived syngas is sufficiently H2-lean such that blending it with the steam methane reforming derived syngas yields a syngas of the appropriate H2/CO ratio of around 2. In a prior work, we also demonstrated that integrating carbonless heat with combined steam and CO2 reforming of methane is a promising option to produce a syngas with proper H2/CO ratio for Fischer... [more]
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