Renewable Fuels : Active Projects

A Review

Overview of polyoxymethylene dimethyl ether additive as an eco-friendly fuel for an internal combustion engine : Current application and environmental impacts

by Omar I. Awad, Xiao Ma, Mohammed Kamil, Obed M. Ali, Yue Ma and ShijinShuai

“Highlights
*   The co-application of PODEn and diesel reduces soot and particulate emissions.
*   Effects of blend ratio on PODEn/diesel blend fuel properties are summarized.
*   The NOx emission-soot correlation can be improved using PODEn-gasoline blends.
*   Euro 5 limits on nitrogen oxides (NOx) and particulate emission can be met using 10 and 20% PODE3–6.”

Abstract

“The combustion of conventional fuels within the transportation sector is a crucial driver of global warming and produces a number of harmful emissions. To decrease these adverse factors, the development of synthetic fuels produced from renewable energy sources via the catalytic conversion of carbon dioxide (CO2) and hydrogen (H2) has progressed significantly. Eco-friendly fuels have a reduced impact on the environment throughout their production and use cycles. In recent years, the use of polyoxymethylene dimethyl ethers (PODEn) as fuels has received an increasing amount of attention, owing to their engine performance and reduced environmental impact. The specific target of this paper is to systematically review the field of PODEn application-based additives as fuel for internal combustion engines. The background and highlights of current and future applications of PODEn are also discussed, and the challenges associated with the use of this additive are also briefly reviewed. A number of studies have shown that the use of fuel mixtures with up to 10% PODE3–4 can have a significant impact on the reduction of engine emissions. PODEn have been shown to reduce the emissions of soot, particulates, CO, and HC under different parameters and working conditions, although NOx and brake-specific fuel consumption (BSFC) emissions have been found to increase. Additionally, PODEn can be produced from natural gas or electric power via CO2 activation in a sustainable manner, which represents a significant benefit with regard to the use of oil-based products. Finally, fossil fuels blended with PODEn can be easily ignited and burned at stoichiometric conditions.”

A Project

Dimethyl Ether Synthesis from Renewables

“Gas Technology Institute (GTI) : Program : REFUEL : ARPA-E Award : $2,300,000
Location : Des Plaines, IL : Project Term : 06/01/2017 to 05/31/2020
Project Status : ACTIVE : Website: https://www.gti.energy/
Technical Categories : Transportation Fuels”

Critical Need

“Most liquid fuels used in transportation today are derived from petroleum and burned in internal combustion engines. These fuels are attractive because of their high energy density and current economics, but they remain partially reliant on imported petroleum and are highly carbon intensive. Domestically produced carbon-neutral liquid fuels (CNLFs), such as dimethyl ether (DME) that is a potential drop-in replacement for diesel engines, can address both of these challenges. Typical fuel production processes require huge capital investments and supporting infrastructure, including base-load power to run continuously. Technology enabling the small- and medium-scale synthesis of liquid fuels can move the production of the fuels closer to the consumer, and – if renewable sources are used – the fuels can be produced in a carbon neutral manner. However, significant technical challenges remain in either changing these processes for smaller scale use or developing alternative electrochemical processes for fuel development. New methods would also have to employ variable rates of production to match the intermittent generation of renewable sources. Improvements in these areas could dramatically reduce the energy and carbon intensity of liquid fuel production. By taking better advantage of intermittent renewable resources in low-population areas and transporting that energy as a liquid fuel to urban centers, we can more fully utilize domestically available resources.”

Project Innovation + Advantages

“Gas Technology Institute (GTI) will develop a process for producing dimethyl ether (DME) from renewable electricity, air, and water. DME is a clean-burning fuel that is easily transported as a liquid and can be used as a drop-in fuel in internal combustion engines or directly in DME fuel cells. Ultimately carbon dioxide (CO2) would be captured from sustainable sources, such as biogas production, and fed into a reactor with hydrogen generated from high temperature water splitting. The CO2 and hydrogen react on a bifunctional catalyst to form methanol and a subsequently DME. To improve conversion to DME, GTI will use a novel catalytic membrane reactor with a zeolite membrane. This reactor improves product yield by shifting thermodynamic equilibrium towards product formation and decreases catalyst deactivation and kinetic inhibition due to water formation. The final DME product is separated and the unreacted chemicals are recycled back to the catalytic reactor. Each component of the process is modular, compact, and requires no additional inputs aside from water, CO2, and electricity, while the entire system is designed from the ground up to be compatible with intermittent renewable energy sources.”

Potential Impact

“If successful, developments from REFUEL projects will enable energy generated from domestic, renewable resources to increase fuel diversity in the transportation sector in a cost-effective and efficient way.”

Security

“The U.S. transportation sector is heavily dependent on petroleum for its energy. Increasing the diversity of energy-dense liquid fuels would bolster energy security and help reduce energy imports.”

Environment

“Liquid fuels created using energy from renewable resources are carbon-neutral, helping reduce transportation sector emissions.”

Economy

“Fuel diversity reduces exposure to price volatility. By storing energy in hydrogen-rich liquid fuels instead of pure hydrogen in liquid or gaseous form, transportation costs can be greatly reduced, helping make CNLFs cost-competitive with traditional fuels.”

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