A team from Stanford University and the California Air Resources Board (ARB) has developed a new open-source lifecycle analysis (LCA) tool for modeling the greenhouse gas emissions of oil and gas production using characteristics of specific fields and associated production pathways. The team describes the Oil Production Greenhouse Gas Emissions Estimator (OPGEE) in a paper in the ACS journal Environmental Science & Technology.
Existing transportation fuel cycle emissions models are either broad—i.e., lacking process-level detail for any particular fuel pathway—and calculate nonspecific values of greenhouse gas (GHG) emissions from crude oil production, or are not available for public review and auditing, the authors note.
Emissions of greenhouse gases (GHGs) from crude oil production vary significantly depending on production practices and crude oil qualities. The use of energy-intensive secondary and tertiary recovery technologies can have significant impacts on emissions. Other major factors are venting, flaring and fugitive (VFF) emissions, which are difficult to measure and estimate. Previous studies show that upstream, well-to-refinery gate (WTR) emissions vary by a factor of 10 from low emissions to high emissions fields. This variability highlights the importance of having the capability to assess the different types of crude oil production operations and under different conditions.
Regulatory approaches, such as the California Low Carbon Fuel Standard (LCFS) and European Fuel Quality Directive (EU FQD), seek to regulate the life cycle GHG emissions for transport fuels.
...To advance the modeling of crude oil production GHGs in a transparent manner, the Oil Production Greenhouse Gas Emissions Estimator (OPGEE) has been developed. OPGEE is built with the goals of achieving more accuracy and better transparency in the assessment of life cycle GHG emissions from crude oil production. OPGEE calculates the energy use and emissions from crude oil production using engineering fundamentals of petroleum production and processing. This allows the model to flexibly estimate emissions from a variety of oil production emissions sources. —El-Houjeiri et al.
In their paper, Hassan El-Houjeiri and Adam Brandt from Stanford, and James Duffy from ARB, introduce OPGEE and its structure, modeling methods, and data sources, then run it in default mode and on a small set of fictional fields (based on real California fields) selected to have varying characteristics and meant to represent a variety of possible operations. These serve to anchor the sensitivity analysis. The results show the GHG emissions breakdown and the sensitivity of emissions to selected input parameters.
The functional unit of OPGEE is 1 MJ of crude petroleum delivered to the refinery entrance (a well-to-refinery, or WTR system boundary), with emissions presented as gCO2 equiv GHGs per MJ of crude at the refinery gate. This functional unit is held constant across different production processes included in OPGEE. The energy content of crude oil at the refinery gate is calculated based on API gravity (no account of effects of other crude oil characteristics such as sulfur content). OPGEE defaults to lower heating value (LHV) basis for all calculations, but model results can also be presented on higher heating value (HHV) basis.
OPGEE calculations use a bottom-up engineering-based approach. OPGEE relies on dozens of calculations across all stages of oil production, processing and transport.
Data for the four fictional fields used in the paper (A, B, C, D) are derived from the online production and injection database and technical reports from the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR).
Field A uses steam injection to decrease crude viscosity. Field B is characterized by very high water-oil ratio (WOR), which represents an inefficient lifting process and significant energy use to manage large amounts of water at the surface (e.g., treatment and re-injection). Field C is characterized by average depth and moderate WOR. Field D is characterized by low depth, low WOR, and higher gas−oil ratio (GOR). The “generic” case uses only the default parameters used to run OPGEE when no data are available.
The researchers explored variation in GHG outcomes due to WOR; field depth; oil production volume; steam-oil ratio (SOR); application of a heater/treater in surface oil−water separation; and flaring rate. OPGEE found that that upstream emissions from petroleum production operations can vary from 3 gCO2/MJ to more than 30 gCO2/MJ using realistic ranges of input parameters. Significant drivers of emissions variation are steam injection rates, water handling requirements, and rates of flaring of associated gas.
Results from OPGEE show clear evidence that assuming a single value for the GHG intensity of oil production is problematic because of significant variation in emissions from different operations. This is particularly the case for regulations aiming to reduce WTW GHG intensity of fuels. Future efforts to better understand and characterize this variation are clearly required. Additional efforts will also focus on improving data availability and the data basis for model defaults.
Future work on OPGEE will address scope limitations and coverage of technologies. Coverage will expand to include oil sands operations, as well as heavy oil and other EOR technologies. Supporting technologies, such as hydraulic fracturing and stimulation, will be included to better represent modern production practices.—El-Houjeiri et al.
The work was funded by ARB.
Resources
Hassan M. El-Houjeiri, Adam R. Brandt, and James E. Duffy (2013) Open-Source LCA Tool for Estimating Greenhouse Gas Emissions from Crude Oil Production Using Field Characteristics. Environmental Science & Technology doi: 10.1021/es304570m
Alcoa expects its $21-million Alcoa Wheel and Transportation Products casthouse expansion at its Barberton, Ohio plant to cut in half the total amount of energy used to recycle aluminum for forged wheels, reducing greenhouse gases and increasing the overall efficiency and sustainability of the company’s manufacturing process. The recycling facility, the first of its kind in North America, produces wheels from re-melted and scrap aluminum.
Construction of the 50,000-square-foot facility, which can process 100 million pounds of scrap aluminum each year, began in July 2011. It is now up and running at full capacity.
100 million pounds of recycled scrap aluminum is enough to make 2 million new Alcoa forged aluminum wheels. The casthouse takes chips and solids from an existing Alcoa wheel machining plant on the same campus in Barberton, as well as from Alcoa’s Cleveland forging plant, and recycles them into aluminum billets. The billets are then shipped to other wheel-processing facilities to forge into aluminum wheels.
The casthouse is expected to reduce significantly energy use through a combination of process improvements and reduced transportation needs. The facility is located on the campus of an existing production facility, which has led an approximately 90% cut in transportation-related energy use.
Aluminum wheels reduce the overall weight of the vehicle, which improves fuel efficiency and reduces greenhouse gas emissions.
This project is also part of the Department of Energy’s Better Buildings Challenge, through which we will share best practices—such as linking energy goals to compensation—to help other companies reduce their industrial energy intensity.—Kevin Anton, Alcoa’s Chief Sustainability Officer
AID (Automotive Industry Data) reports that first-time registrations in April of electric vehicles in Western Europe were up almost one-half to just under 2,600 units, representing 0.26% of the region’s new car market.
Registrations of electric cars this April were up in eight markets, down in seven, AID reported. France, thanks to the launch of the Renault ZOE, currently ranks as the region’s largest electric car market, with 3,188 new electric car registrations during the first four months of this year.
French electric car registrations in April more than doubled to 940 units, according to AID.
Researchers from Ben-Gurion University of the Negev and Ormat Industries Ltd. in Israel report the development of a comercially-viable, one-step catalytic hydrotreating process for the conversion of soybean oil to renewable diesel-type fuel in a paper in the journal Fuel.
The conversion of soybean oil to green diesel was carried out on Pt/SAPO-11-Al2O3 catalyst in a trickle-bed reactor. Steady-state operation was reached after about 150 h. The steady-state performance was recorded at 375–380 °C, 30 atm and LHSV = 1 h−1.
The green diesel produced in this study was characterized according to ASTM procedures by a certified lab. Most of its properties were found to fit the standard of qualified diesel fuel (European standard EN-590) making it an excellent component for diesel fuel blends.
Resources
Moti Herskowitz, Miron V. Landau, Yehudit Reizner, Dov Berger (2013) A commercially-viable, one-step process for production of green diesel from soybean oil on Pt/SAPO-11, Fuel, Volume 111 Pages 157-164, doi: 10.1016/j.fuel.2013.04.044
A team including researchers from Hanyang University (South Korea) and University of Rome Sapienza (Italy) have shown that operating temperature plays an important role in the performance of Lithium-air batteries. They also demonstrated “to the best of our knowledge for the first time” that a lithium-air battery, fabricated with optimized electrodes and electrolyte, may successfully operate in a temperature range extending from −10 to 70 °C.
The electrochemical and morphological study of the response of Li-air cells cycled at various temperatures is published in the ACS journal Nano Letters.
Lithium-air (or Li-oxygen) batteries are attracting a great deal of research interest due their very high energy densities, and thus their potential application in electric vehicles.
In its most classical configuration, the Li/O2 battery is formed by a lithium metal anode, a liquid organic electrolyte and a carbon-supported (with or without catalyst) air electrode. Recently, a new configuration, where the lithium metal is replaced by a lithium alloy silicon anode, has also been reported. Key parameters in assuring proper Li/O2 battery behavior are (i) the optimization of the positive electrode structure, in terms of use of an adequate gas diffusion layer and of effective catalysts, and (ii) the choice of an electrolyte stable to superoxide attack.
It is in fact well-known that the basic electrochemical cell process, leading to the reversible formation and dissolution of lithium peroxide, involves an intermediate oxygen anion radical O2−•, namely, a highly reactive base that readily attacks and decomposes conventional electrolytes, such as organic carbonate solutions. Dimethoxyethane (DME)-based and ionic liquid-based solutions have been proposed as alternative electrolyte media, however with little success.
Recent works demonstrated that the best results in terms of Li/O2 battery stability and cycling may be obtained with the use of long chain, ether-based glymes, such as tetraethylene glycol dimethyl ether (TEGDME) electrolyte solutions. [Earlier post.] In a previous paper we have reported a detailed transmission electron microscopy (TEM) study showing that Li/O2 batteries based on the TEGDME-LiCF3SO3 electrolyte indeed show a very promising behavior at room temperature. In this paper we extend the study by investigating the role of temperature on influencing the response of Li/TEGDME-LiCF3SO3/O2 cells.—Park et al.
The Li-air cells in the study were based on a specially developed gas diffusion layer (GDL) oxygen electrode and on a TEGDME-LiCF3SO3 electrolyte. The gas diffusion layer was coated with Super-P carbon as matrix to host the lithium oxygen reaction products (Li2O2 nanospheres and hollow nanospheres formed at the interface with the tetraglyme-based solution). All of the cycles were run under a fixed capacity regime of 1000 mAh g−1carbon.
Low temperatures resulted in a rate decrease, due to a reduced diffusion of the lithium ions from the electrolyte to the electrode interface. High temperatures resulted in a rate enhancement, due to the decreased electrolyte viscosity and consequent increased oxygen mobility.
They also showed that the temperature also influences the crystallinity of lithium peroxide formed during cell discharge.
Resources
Jin-Bum Park, Jusef Hassoun, Hun-Gi Jung, Hee-Soo Kim, Chong Seung Yoon, In-Hwan Oh, Bruno Scrosati, and Yang-Kook Sun (2013) Influence of Temperature on Lithium–Oxygen Battery Behavior. Nano Letters doi: 10.1021/nl401439b
Russian oil and gas major Rosneft, 75% owned by the government, and the Venezuelan Corporacion Venezolana del Petroleo (CVP), a subsidiary of PDVSA, signed an agreement to create a joint venture to develop heavy oil reserves in Venezuela in the framework of the Carabobo-2 project. (Earlier post.
Rosneft’s stake in the joint venture will amount to 40%, the other 60% will be held by CVP. The Carabobo-2 project includes blocks Carabobo-2 North and Carabobo-4 West with a total area of 342 square kilometers located in the Orinoco river’s heavy crude belt. Reserves at the blocks are estimated at 40 billion barrels (6.5 billion tonnes). Commercial oil production is expected to peak at more than 400 thousand barrels per day (about 25 million tonnes per year).
According to the memorandum, Rosneft is to pay a bonus of $1.1 billion for entering the project in two tranches (40% and 60%) and also to offer a loan of $1.5 billion to Corporacion Venezolana del Petroleo with the maximum yearly take-off of $0.3 billion.
The joint venture plans to perform the entire cycle of site exploration and development, building ground facilities and field pipelines. There are also plans for building an upgrader to increase the quality of the extracted oil.
The Orinoco Belt contains heavy and extra-heavy oil with a range of gravities from 4 to 16 degrees API (a measure of density) as well as large deposits of natural bitumen (i.e., oil sands). The US Geological Survey (USGS) characterizes extra-heavy oil as having an API gravity of less than 10°. Natural bitumen shares the attributes of heavy oil but can be yet more dense and viscous. According to the Government of Alberta, Canada, Athabasca bitumen has an API gravity number of less than 10°.
President and Chairman of the Management Board Igor Sechin said that the new joint venture would be named Petrovictoria. The companies actively work on other new projects including the Venezuelan shelf, he also added.
The companies have also signed a confidentiality agreement allowing Rosneft to obtain geological data on Venezuelan offshore blocks for possible future cooperation.
Earlier Rosneft and the Venezuelan company had signed a memorandum of intent to study several gas sites on this country’s shelf.
EcoCAR 2: Plugging In to the Future named Pennsylvania State University its Year Two winner at the EcoCAR 2013 Competition in San Diego. The 15 universities competing in EcoCAR 2 gathered in Yuma, Arizona last week for six days of vehicle testing and evaluation on drive quality and environmental impact at General Motors (GM) Desert Proving Ground. From there, the competition moved to San Diego for a second round of judging by automotive industry experts.
The Penn State University Advanced Vehicle Team (PSU AVT) designed a series plug-in hybrid electric vehicle (PHEV) fueled with E85. The converted 2013 Chevrolet Malibu uses a front-wheel-drive system powered by a Magna E-Drive motor with a 90 kW electric drive unit to supply the propulsion for the converted Malibu. For the auxiliary power unit, the PSU AVT uses a Weber MPE 750 engine fueled with E85, coupled to a UQM PowerPhase 75 generator to supply DC power to the high-voltage bus. The vehicle uses lithium-ion-phosphate batteries to form the basis for the energy storage system.
After a year creating and testing their eco-vehicle designs using technologies such as Hardware-In-the-Loop (HIL) simulation, teams spent the second year of EcoCAR 2 utilizing advanced automotive engineering processes to redesign their Malibu vehicles.
Argonne National Laboratory and GM engineers subjected these vehicles to extensive safety inspections and on-road evaluations, similar to those conducted on new GM vehicles. Each car was evaluated on reduced fuel consumption and greenhouse gas emissions as well as performance, utility and safety.
Pennsylvania State University was named this year’s winner after impressing inspectors and other judges representing various EcoCAR 2 sponsors with its E85 plug-in hybrid electric vehicle. The team was the first to pass safety and technical inspections, on-road safety evaluation as well as run all the competition dynamic events.
The second place team, Cal State Los Angles, excelled with its ethanol-fueled vehicle and was the first team to complete all the dynamic events. The Ohio State University took third place overall after demonstrating its series-parallel hybrid electric vehicle.
The 15 university teams will now spend Year Three of EcoCAR 2 perfecting their designs before the competition finals in Washington, D.C., in May 2014.
During an international press event in Germany, in which more than 42 test drives were conducted with journalists in the Panamera S E-Hybrid (earlier post) covering a total distance of more than 1,200 kilometers (746 miles), the new plug-in hybrid model consumed 4.4 l/100 km (53.4 mpg US) averaged over all drives.
The lowest fuel consumption value recorded on the circuit course for the Panamera plug-in hybrid was 2.8 l/100 km (84 mpg US). NEDC testing indicates combined cycle fuel consumption of 3.1 l/100 km (75.9 mpg US) for the PHEV, with accompanying CO2 emissions (combined) of 71 g/km. Electrical consumption (combined) is rated at 162 Wh/km.
The test drive results were obtained from four unmodified Panamera S E-Hybrid production cars, each carrying three to four people, with the climate control system activated and accelerating up to 230 km/h (143 mph) on the highway section of the route.
The test circuit, which had a total length of 28.7 km (17.8 miles), followed a course through and around the city of Hockenheim and comprised 6.5 km (4.0 miles) city driving, 9.2 km (5.7 miles) of country roads and 13 km (8 miles) of German Autobahn—some without speed limits.
A prerequisite for attaining such fuel consumption values is systematically exploiting opportunities for charging the 9.4 kWh lithium-ion battery on the electrical grid, Porsche noted.
The car’s range of 36 kilometers (22.4 miles) in all-electric driving was also confirmed in practice with a fuel consumption value of 0.0 l/100 km and zero local emissions, which was not only attainable in NEDC testing on a dynamometer, but also on the street. The car attains this value at an average speed of 54 km/h (33.6 mph), while the average speed in NEDC testing is just 33 km/h (20.5 mph).
Powertrain. The Panamera S E-Hybrid features a new Euro 6-compliant turbocharged 3.0L direct-injection V6 engine that delivers 245 kW (329 hp) of power and 440 N·m (325 lb-ft) of torque; three-phase 70 kW synchronous motor developing maximum torque of 310 N·m (229 lb-ft); an 8-speed Tiptronic S transmission with Normal and Sport shifting programs and a separate shifting strategy for E-Power mode; and a 9.4 kWh Li-ion battery pack.
The Panamera S E-Hybrid offers a combined system power of 416 hp (306 kW), accelerates from zero to 100 km/h in 5.5 seconds and has a top speed of 270 km/h (168 mph). The electric drive produces 95 hp (71 kW), with maximum torque of 310 N·m (229 lb-ft).
The Panamera S E-Hybrid offers multiple modes that can be selected by pushbuttons on the center console. The E-Power mode—activated by default, provided that the battery charge state is sufficient—enables largely all-electric driving.
The total system power can be accessed at any time by kickdown, such as to overtake another vehicle. In this case, the E-Power mode remains activated in background, and it enables all-electric driving as soon as acceleration returns to a moderate level, and the electric top speed is not exceeded.
When E-Power is deactivated, the operating strategy switches to Hybrid mode. This operating strategy—programmed for efficiency—fully automatically switches between the driving states of electric driving, hybrid driving with load point shift, coasting, electrical system recuperation and boosting.
Here the E-Power Assistant, which the driver can select in the instrument cluster’s TFT display, can precisely meter, based on the display, whether the car is driven all-electrically or with support of the combustion engine. Essentially, the system “reserves” the battery’s available energy capacity for later electric driving phases by switching to Hybrid mode and engaging the six-cylinder engine earlier.
The E-Charge mode is a newly developed driving mode that is activated by a pushbutton on the center console. It charges the high-voltage battery during the drive. Here, the electric motor acts as a generator, which increases load on the combustion engine until the engine is operating in very efficient load ranges. This energy is stored in the traction battery so that it will be available for later zero-emissions driving.
This mode increases the car’s electric range on drives with a high proportion of combustion engine use—e.g. on highway drives that are followed by a route through the city. In other words, the battery can be charged during the motorway driving, so the city route can be driven all electrically. In stop-and-go traffic within the city, battery charging is reduced for efficiency reasons to preserve typical hybrid characteristics in E-Charge mode as well, such as shutting off the combustion engine when the vehicle is stopped and slow electric drive-off.
As in the previous conventional hybrid model, the brake system of the new Panamera S E-Hybrid enables recovery of braking energy. The generator function of the electric motor might be activated first, absorbing up to the maximum possible load, then the conventional brake would be superimposed, depending on how hard the driver presses the brake pedal. This battery regeneration map differs from that of the previous hybrid, and was adapted to the new electric motor that is more powerful, and it was further optimized for driveability and pedal feel.
Rounding out the driver’s options is the Sport mode for typical Porsche high performance and a special sporty characteristic with more direct handling.
Motor and battery. At 95 hp (70 kW), the newly developed electric motor is 48 hp stronger than the motor in the previous model—peak power has more than doubled. Since its weight remained nearly constant, this improved the power-to-weight ratio of the electric motor from 1.1 kg/kW to 0.54 kg/kW.
Maximum torque increased ten-fold to 310 Nm. This performance increase of the three-phase synchronous motor is attributable to a modified number of windings on the coils and an increased voltage level. A different magnetic material was used in the electromagnetic circuit as well, and an optimized cooling channel geometry improves the motor’s thermal resistance.
Evolution of Porsche hybrid modules Cayenne and Panamera S Panamera SThese modifications are roughly equivalent to a power increase attained by increasing the displacement of a combustion engine and introducing high-performance cooling, Porsche said.
The newly developed electric motor is subjected to far greater stresses than before. For example, the E-Power mode demands quick response with high peak powers and high thermal resistance of the electric motor. High electrical system recuperation performance must be assured in all driving modes. The driver can summon extended boost phases up to the car’s top speed in Sport mode and by kickdown.
The new E-Charge mode poses the most stringent requirements. During charging phases with their high torques that are optimal for efficiency subject the electric motor to high stresses while it operates as a generator. However, the electric motor’s peak power must remain accessible for E-Power mode. In addition, it is necessary to assure comfortable and quick restarting of the combustion engine and the supply of electricity to the vehicle electrical system.
The performance partner which stores energy for the electric motor is a newly developed 384V Li-ion battery. With a capacity of 9.4 kWh, it offers five times the storage capacity of the NiMH battery in the previous conventional hybrid model, yet it does not require any additional installation space. Like before, it is integrated in a space-saving location under the trunk floor.
Decoupler with extended tasks. A key drivetrain component of the parallel full hybrid is the clutch between the combustion engine and the electric motor. The drive system always chooses the starting sequence that best satisfies driver wishes while taking into account comfort and dynamics. Multiple processes run simultaneously in the starting phase.
When the combustion engine is coupled, the lock-up of the torque converter in the automatic transmission disengages, and the torque of the electric motor is briefly increased to start the six-cylinder engine. Simultaneously, the clutch between the electric motor and the combustion engine engages with a defined pressure characteristic. Along with the well-engineered interplay of combustion engine and electric motor, the spindle actuator of the clutch control unit supplies the hydraulic pressure needed to activate the clutch.
The layout of the decoupler for the Panamera S E-Hybrid was adopted from the previous model. The system consists of a friction disc with torsion damper and pressure plate with integrated central release mechanism. It is completed by the flywheel that is integral to the crankshaft. Its operating states have changed due to the extended functionality of the Panamera S E-Hybrid.
For example, the significantly larger battery capacity and power-enhanced electric motor have resulted in longer electric driving periods and fewer combustion engine restarts. These modified requirements made it necessary to extend the software for control of the decoupler system.
All of this places high requirements on the components and the control system. The Hybrid Manager coordinates the interplay between combustion engine, electric motor with decoupler and transmission. Conditions of the high-voltage system are also considered here, such as temperature and the battery charge state. They are continually monitored by the Battery Management System, which communicates with the Hybrid Manager.
Combustion engine with extended operating strategy. The primary drive source is the 3.0L engine. Fuel economy was significantly improved by using an optimized thermal management system to distribute heat more precisely and a further developed operating strategy with intelligent control of catalytic converter heating.
After the vehicle has been parked at freezing temperatures overnight, for example, an electric cold start is now possible down to an engine oil temperature of zero degrees Celsius. Previously, this limit was 15 degrees Celsius. The starting sequence was also improved to make the power of the combustion engine available to the driver even faster when the accelerator is pressed after electric driving. Many of the auxiliary systems are now electric as well to guarantee their functionality during all-electric driving.
8-speed Tiptronic. Porsche relies on the proven Tiptronic S for power transmission. It was possible to use the eight-speed automatic transmission without component modifications in the Panamera S E-Hybrid, despite higher shares of electrical system recuperation and the power-enhanced electric motor. However, the control system for the transmission was fundamentally redesigned, and it was extended to perform additional functions.
In E-Power mode, for example, a special shifting strategy was implemented based on the modified electric motor characteristic. Unlike Hybrid mode, it utilises a higher rev level over the entire relevant speed range for optimal efficiency. These changes have resulted in different torque relationships in the lock- up torque converter. Therefore, transmission control was extended for the restart process. For the Sport mode, a hybrid-specific, emotionalized gear shifting strategy is also stored in the control unit. In this case, gear selection always assures the best possible balance of longitudinal dynamics, acoustics and fuel economy.
Two coolant loops. To realize their full performance and efficiency capabilities, the components of the hybrid drive need different but precisely defined operating temperatures. Therefore, requirements for the coolant loop in the new Panamera plug-in hybrid have been increased compared to the previous model. Along with the high-temperature loop for the combustion engine and electric motor, two low-temperature circulation loops in the Porsche Panamera S E-Hybrid assure efficient cooling over all relevant operating ranges.
For example, the coolant supply to the electric motor was optimized to significantly reduce temperature levels, especially in E-Power mode. Along with optimal positioning of the temperature sensor in the coolant flow, this permits precise control of the active electric motor components.
The two intercoolers and the power electronics were integrated in the previous low-temperature circulation loop. The new second temperature loop is exclusively designed for thermal management of the lithium-ion battery. When the battery’s temperature exceeds a certain value, it can also be cooled by a heat exchanger in the cooling loop. Moreover, an electric heating element (PTC heater) integrated in the battery housing assures functionality of the energy storage device down to the Arctic temperature range.
Next-generation hybrid module: more power, new cooling strategy. The next generation of the Porsche hybrid drive has already attained a very advanced development level. Project specifications call for an electric motor which has more than one-third more power than that of the Panamera S E-Hybrid with more than 95 kW of power; its torque also increases by just around 30%. This leads to greater needs to remove heat, which is necessary during high and long-duration power output.
Porsche engineers developed a new cooling strategy, in which the stator—the stationary exterior part of the electric motor—is still water-cooled, as before. However, the coils of the inner rotating part are air- cooled. This is accomplished by a blower wheel that draws in outside air via an air channel with flow distributor.
The heat is rejected via a large number of channels integrated in the housing. This solution guarantees uniform flow distribution and cooling of the coils for maximum electric performance, and it combines high levels of integration density and optimal package utilization, the company said.
The new Panamera S E-Hybrid will be at dealers starting 27 July 2013.
Pacific Gas and Electric Company (PG&E) and the California Energy Commission today unveiled a utility-scale sodium-sulfur battery energy storage system (earlier post) pilot project to better balance power needs of the electric grid. The system has a 4 megawatt capacity, and can store more than six hours of energy.
The Yerba Buena Battery Energy Storage System Pilot Project charges batteries when demand is low and then sends reserved power to the grid when demand grows. The system has the potential to provide important services for balancing energy supply and demand, helping to support greater integration of intermittent renewable generation, as well as improving power quality and reliability for customers.
The project was made possible with a $3.3-million grant from the Energy Commission to PG&E that will help fund the installation and evaluation of the system.
PG&E is working in close coordination with the Electric Power Research Institute (EPRI) to study how sodium-sulfur battery energy storage can improve power quality and reliability; support greater integration of intermittent renewable power; and supply energy to California’s electricity market, overseen by the California Independent System Operator. EPRI’s reports will be made available to the public.
S&C Electric Company is the engineering, procurement and construction contractor for the project and supplied the storage management system and power conversion equipment that control the battery’s AC input/output and its interface with the electric grid.
NGK Insulators (earlier post) is the manufacturer of the sodium sulfur (NaS) battery system which includes the battery modules and control system for managing DC input/output and other parameters for maximizing module longevity.
Cyclone Power Technologies, developer of the all-fuel, external combustion Cyclone Engine, and McGill University of Québec, Canada have signed a Memorandum of Understanding (MOU) to develop alternative solid fuel combustion systems for micro-sized power units.
Cyclone has identified a business line for its external combustion technology in providing universal portable power for next-generation battery charging, as well as mechanical shaft power for autonomous robots, exoskeletons and bio-medical systems. Cyclone views this as a long-term opportunity in a growth industry with substantial global impact.
Critical to achieving system size constraints for portable power and robotics, however, is developing high-power-density thermal sources and combustion systems for next generation Cyclone engines.
McGill’s research in the controlled combustion of energy-dense solid fuels is one of the most advanced programs in the discipline, and can possibly lead to massive technological leaps in generating heat to run micro-scale external combustion engines, Cyclone said.
This early-staged project is part of a larger plan to expand Cyclone’s base technology beyond our current programs and into additional cutting edge markets for the future—integrating ourselves with Lithium-ion batteries, fuels cells and advanced robotics. These growth sectors range from enhancing human capabilities, to human-robotic interaction in medical devices, to even space exploration. It is a logical maturing of Cyclone’s founding mission of innovation to pursue these forward looking opportunities, especially with leading research institutions like McGill.—Christopher Nelson, President of Cyclone
Cyclone and McGill worked on a project submission previously to the Department of Energy’s ARPA-E program, and although not initially selected for funding, it began a relationship between the two entities. Cyclone’s interest in micro-sized power units began several years ago with its 100W “Genie” concept, which was put on-hold pending additional funding and strategic partners.
Cyclone believes that McGill’s knowledge in high power density fuel systems is essential to obtaining required performance levels, and anticipates inclusion of several more renowned research universities and technology innovation companies to advance the goals of this project.
Total US petroleum deliveries (a measure of demand) were up 0.3% for April against the same month a year ago to average nearly 18.4 million barrels per day, but still recorded the second lowest April demand level in 17 years, according to the American Petroleum Institute (API). Gasoline demand fell 3.9% from April 2012 to its lowest April level since 2000.
For the second month demand is up from a year ago. Consumer confidence has improved and distillate deliveries are up, but gasoline demand remains weak.—API Chief Economist John Felmy
Gasoline demand averaged 8.5 million barrels per day for the month, while distillate deliveries at 3.8 million barrels per day were up 1.4% from April a year ago. Kerosine-jet fuel demand was down 1.8 %, and residual fuel oil demand was down by 22.8%.
Demand for “other oils”—which include liquid petrochemical feedstocks, naphtha, and gasoil and are nearly one-fourth of total deliveries—was up 12.5% in April from April 2012.
Refinery gross inputs were above 15.0 million barrels per day for the first time this year. Production of all major refined products—gasoline, distillates, jet fuel, and residual fuels—was higher than deliveries, so products were exported, increasing by 1.0% from this March.
At nearly 8.9 million barrels per day, gasoline production rose to its third highest April output ever, increasing by 2.2% from March 2013 and 1.3% from April 2012. Production of distillate fuel and jet fuel were also up, with distillate production at 4.5 million barrels per day achieving its highest April level ever.
Total US crude oil production remained above 7.0 million barrels per day for the sixth month in a row and was at a 21-year high at 7.3 million barrels per day, a 1.7% increase from March and 15.9% higher than April 2012. The number of oil and gas rigs decreased from 1,756 in March to 1,755 in April, according to the latest reports from Baker-Hughes, Inc.
April crude oil stocks ended at 388.9 million barrels, the highest inventory level for the month since 1981. Motor gasoline stocks at 218.0 million barrels were down by 1.4% but up 3.6% from the same month a year ago. Distillate fuel stocks ended at a five-year low, down 7.1% to 115.7 million barrels from year ago levels.
Total imports were below 10.0 million barrels per day for only the third time in over 15 years, falling 6.4% from April last year. With increased crude production and record crude inventories, crude oil imports in April were at their lowest in 16 years, falling 6.7% from April 2012 to 8.0 million barrels per day. Refined product imports were down 5.0% from the previous April to average 1.9 million barrels per day.
The refinery utilization rate averaged 86.5% for April 2013, up 2.6% from the prior month but down 0.1% from April 2012. API’s latest refinery operable capacity was 17.820 million barrels per day up from 17.718 million barrels per day this past March.
The new 2014 Chevrolet Impala offers as one of its three engine options a four-cylinder Ecotec 2.5L engine, featuring the debut of a new advanced variable valvetrain technology—Intake Valve Lift Control (IVLC, earlier post)—and improved fuel economy. The EPA estimated fuel economy for the 2014 Impala with the new 2.5L engine is 21 mpg city and 31 mpg highway (11.2 and 7.6 l/100 km, respectively).
The 2.5L engine, which delivers SAE-certified 196 horsepower (146 kW) and 186 lb-ft of torque (252 N·m), achieves variable valve lift using an all-new rocker arm that switches between low and high lift intake cam profiles.
The mechanism is actuated by an oil control valve through a dual-feed stationary hydraulic lash adjuster. It is the first of its kind for low friction roller-type finger-follower valvetrains in gasoline engines, GM says. The engine’s computer continuously selects the optimal lift profile based on conditions such as engine speed and load.
When the technology operates in low-lift mode, the engine pumps only the air it needs to meet the driver’s demand. The system switches to high-lift mode at higher engine speeds or under heavy loads, providing the full output capability of the engine.
Intake Valve Lift Control works so seamlessly drivers aren’t likely to notice it at all. What they will notice is a fuel economy improvement of up to one mile per gallon.
—Mike Anderson, General Motors’ global chief engineer for Ecotec enginesQuiet. The redesigned large sedan’s 2.5L engine with direct injection is engineered to be one of the quietest and most refined in the segment. The development team reduced engine noise intensity by 40% by specifically targeting the 2.5L’s noise frequency signature. They pushed radiated noises into a higher frequency range well above 2,000 hertz, which is more pleasing to the ear—particularly in the high-load operating ranges where engine sound is most intense.
The refinement-enhancing changes and improvements over previous Ecotec engines ranged from the comparatively simple—such as integrating a sound-absorbing cover into the intake manifold and specifying quieter drive chains—to more fundamental architecture items, such as relocating the balance shafts from the cylinder block to a cassette within the oil pan.
Impala’s passengers get a quieter driving experience due in part to active noise-canceling technology and a more refined sound as the engine revs to its 7,000-rpm peak.
Chevrolet expects the 2.5L model to be a popular choice among Impala buyers. The other engine options are a 3.6L V-6 and the Ecotec 2.4L with eAssist. More than two-thirds of Chevrolet cars sold in the first quarter of 2013 had a four-cylinder engine.
Synopsys, Inc., a provider of software, IP and services used to accelerate innovation in chips and electronic systems, announced the availability of the Virtualizer Development Kit (VDK) for Renesas RH850 MCUs to accelerate software development, system integration and test for RH850-based automotive applications such as body, powertrain/hybrid and chassis/safety control.
VDKs are software development kits integrating design-specific virtual prototypes with software debug and analysis tools. The new VDK is the first commercial deliverable from the Center of Excellence collaboration between Renesas and Synopsys.
The VDK enables automotive engineers designing RH850-based electronic control units (ECUs) to start developing, integrating and testing software months before ECU hardware is available, resulting in higher product quality and reduced development cost.
The availability of the Synopsys VDK for Renesas’ RH850 MCU marks a key milestone in our long-term collaboration and provides developers of RH850-based applications a productive software development solution. As software content and complexity in automotive ECUs continues to grow, our customers can take advantage of leading virtual prototyping technology that has been adapted for the RH850 family, so they can start their software development tasks earlier and accelerate system integration, test and validation.—Akihiko Watanabe, Department Manager of Automotive Electronics Core Technology Department, Renesas Electronics
Renesas’ RH850 MCUs are an advanced family of scalable, 32-bit microcontrollers that have been specially tuned for the performance and reliability requirements of a wide variety of automotive applications such as safety, body and engine control, driver interfaces and infotainment.
The VDK for RH850 MCU includes reference virtual prototypes representing a microcontroller, including single and multicore versions of the RH850, timers, memories, communication blocks such as LIN, CAN and Ethernet and analog and error control modules.
The initial release of the new VDK includes a virtual prototype following the F1x MCU memory map. The virtual prototype can be modified to represent other RH850 MCU series and to create additional VDKs, such as E1x, C1x and P1x, with the Virtualizer tool set.
The VDK for RH850 MCU readily integrates with tools such as Mathworks Simulink, Synopsys Saber, Vector CANoe and third party debuggers, enabling system integration and test using a virtual Hardware-in-the-Loop environment and fault and coverage testing in support of the ISO 26262 safety standard.
The VDK for Renesas RH850 MCU is available immediately from Synopsys.
An international team of researchers has developed a new metal-organic framework (MOF) that might provide a significantly improved method for separating hexane isomers in gasoline according to their degree of branching. A paper on the work is published in the journal Science.
Created in the laboratory of Jeffrey Long, professor of chemistry at the University of California, Berkeley, the MOF features triangular channels that selectively trap only the lower-octane hexane isomers based on their shape, separating them easily from the higher-octane molecules in a way that could prove far less expensive than the industry’s current method for producing high-octane fuel. The Long laboratory and UC Berkeley have applied for a patent on the MOF Fe2(bdp)3. (BDP2– = 1,4-benzenedipyrazolate)
High-octane gasolines are more expensive than regular unleaded gasoline due to the difficulty of separating out the right type of molecules from petroleum. Petroleum includes several slightly different versions of the same molecule that have identical molecular formulae but varying shapes (isomers).
Creating premium fuel requires a refinery to boil the mixture at precise temperatures to separate the isomers with the most chemical energy. However, four of these isomers—two of which are high octane, the other two far lower—have only slightly different boiling points, making the overall process both challenging and costly.
The new MOF, however, could allow refineries to sidestep this problem by essentially trapping the lowest-octane isomers while letting the others pass through. The lowest-octane isomers are more linear and can nestle closer to the MOF walls, so when a mixture of isomers passes through the MOF, the less desired isomers stick to its surface.
Consistent with the varying abilities of the isomers to wedge along the triangular corners of the structure, adsorption isotherms and calculated isosteric heats indicate an adsorption selectivity order of n-hexane > 2-methylpentane > 3-methylpentane > 2,3-dimethylbutane ≈ 2,2-dimethylbutane. A breakthrough experiment performed at 160 °C with an equimolar mixture of all five molecules confirms that the dibranched isomers elute first from a bed packed with Fe2(BDP)3, followed by the monobranched isomers and finally linear n-hexane. Configurational-bias Monte Carlo simulations confirm the origins of the molecular separation.—Herm et al.
The Supplementary Materials for the paper contains a detailed discussion of the separation potential of Fe2(BDP)3 for producing high-octane gasoline (RON 92). The team concluded that the separation into three fractions based on the degree of branching, rather than on C number, is evident. The implications of this fractionation ability is that it is possible to utilize Fe2(BDP)3 in the separation step of a C5/C6/C7 alkane isomerization process scheme.
The discussion also compares the new MOF with the separation performance of other adsorbents.
Matthew Hudson and his colleagues at the NIST Center for Neutron Research (NCNR) used neutron powder diffraction, a technique for determining molecular structure, to explore why the MOF has the right shape to selectively separate the isomers. Their research was essential to validate the team’s model of how the MOF adsorbs the low-octane isomers.
It’s easier to separate the isomers with higher octane ratings this way rather than with the standard method, making it more efficient. And based on the lower temperatures needed, it’s also far less energy-intensive, meaning it should be less expensive.—Matthew Hudson
Hudson says that while industrial scientists will need to work out how to apply the discovery in refineries, the new MOF appears to be robust enough in harsh conditions to be used repeatedly a great many times, potentially reducing the necessary investment by a petroleum company.
Resources
Z.R. Herm, B.M. Wiers, J.A. Mason, J.M. van Baten, M.R. Hudson, P. Zajdel, C.M. Brown, N. Masciocchi, R. Krishna and J.R. Long (2013) Separation of hexane isomers in a metal-organic framework with triangular channels. Science, doi: 10.1126/science.12334071
Researchers at Duke University have developed a novel graphene–sulfur–carbon nanofibers (G-S-CNFs) multilayer and coaxial nanocomposite for use as the cathode of Li–sulfur batteries with increased capacity and significantly improved long-cycle stability.
Electrodes made with the G-S-CNFs were able to deliver a reversible capacity of 694 mA h g–1 at 0.1C and 313 mA h g–1 at 2C—both substantially higher than electrodes assembled without graphene wrapping. More importantly, the long-cycle stability was significantly improved by graphene wrapping, they noted in their paper published in the ACS journal Nano Letters.
The cathode made with G-S-CNFs with a initial capacity of 745 mA h g–1 was able to maintain 273 mA h g–1 even after 1500 charge–discharge cycles at a high rate of 1C, representing an extremely low decay rate (0.043% per cycle after 1500 cycles). As a comparison, the capacity of an electrode assembled without graphene wrapping decayed significantly with a 10 times high rate (0.40% per cycle after 200 cycles).
They attributed the improved rate capability and cycle stability to the unique coaxial architecture of the nanocomposite, in which the contributions from graphene and CNFs enable electrodes with improved electrical conductivity, better ability to trap soluble the polysulfides intermediate and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles.
...sulfur based lithium batteries are of particular promise for next-generation energy storage systems. However, despite of these promises, several challenges exist for Li−S batteries that hindered their commercial applications. Such challenges include the inherent low electrical conductivity of sulfur (5 × 10−30 S cm−1), which results in limited active material utilization efficiency and rate capability, and shuttling of high-order polysulfides between cathode and anode and high solubility of polysulfide intermediates in the electrolyte, both of which lead to limited cycle stability. Additionally, sulfur experiences severe volumetric expansion/ shrinkage during charge and discharge (∼80%), which gradually decreases the mechanical integrity and hence stability of the electrode over cycles.
...Here we report an approach to assemble graphene−sulfur− carbon nanofiber (G-S-CNF) coaxial structured nanocomposite with sulfur sandwiched between graphene and CNFs that can be used as cathode for Li−S batteries with significantly improved cycle stability and capacity.
In our approach, sulfur was first coated uniformly on the surface of CNFs and then graphene was used to wrap around the whole structure. In this well designed structure, both CNFs and graphene serve as good conducting fillers to improve the overall conductance of the film. More importantly, graphene over-coated on S limited the dissolution of polysulfide intermediate, while CNFs provided much needed mechanical stability of the film. —Lu et al.
The work was supported in part by a research grant from the National Science Foundation (NSF) and the Environmental Protection Agency (EPA).
Resources
Songtao Lu, Yingwen Cheng, Xiaohong Wu, and Jie Liu (2013) Significantly Improved Long-Cycle Stability in High-Rate Li–S Batteries Enabled by Coaxial Graphene Wrapping over Sulfur-Coated Carbon Nanofibers. Nano Letters doi: 10.1021/nl400543y
