Researchers at MIT and in Saudi Arabia say they have found an economical solution to cleaning out the biggest pollutant from hydraulic fracturing oil and gas wells. The pollutant is salt in the water used to fracture the rock, that’s much saltier than seawater, after leaching salts from deep below the surface.
The boom in oil and gas produced through hydraulic fracturing, or fracking, is also a boon for meeting U.S. energy needs. The team’s new analysis appears this week in the journal Applied Energy, in a paper co-authored by MIT professor John Lienhard, postdoc Ronan McGovern, and four others.
The method they propose for treating the “produced water” that flows from oil and gas wells throughout their operation is one that has been known for decades, but had not been considered a viable candidate for extremely high-salinity water, such as that produced from oil and gas wells. The technology, electrodialysis, “has been around for at least 50 years,” says Lienhard, the Abdul Latif Jameel Professor of Water and Food as well as director of the Center for Clean Water and Clean Energy at MIT and King Fahd University of Petroleum and Minerals (KFUPM).
Water recovered from fossil-fuel wells can have salinity three to six times greater than that of seawater; the new research indicates that this salt can be effectively removed through a succession of stages of electrodialysis.
“Electrodialysis is generally thought of as being advantageous for relatively low-salinity water,” Lienhard says — such as the brackish, shallow groundwater found in many locations, generally with salinity around one-tenth that of seawater. But electrodialysis also turns out to be economically viable at the other end of the salinity spectrum, the new analysis shows.
The idea would not be to purify the water sufficiently to make it potable, the researchers say. Rather, it could be cleaned up enough to enable its reuse as part of the hydraulic fracturing fluid injected in subsequent wells, significantly reducing the water needed from other sources.
Lienhard explains that if you’re trying to make pure water, electrodialysis becomes less and less efficient as the water gets less saline, because it requires that electric current flow through the water itself: Salty water conducts electricity well, but pure water does not.
McGovern, a postdoc in MIT’s Department of Mechanical Engineering and lead author of the paper, says another advantage of the proposed system is “flexibility in the amount of salt we remove. We can produce any level of output salinity.” The costs of installing an electrodialysis system, he says, appear to compare favorably to other widely used systems for dealing with produced water.
It’s not clear at this point, McGovern says, what the optimal salinity is for fracking fluids. “The big question at the moment is what salinity you should reuse the water at,” he says. “We offer a way to be able to control that concentration.”
Before reaching the desalination stage, the researchers envision that chemical impurities in the water would be removed using conventional filtration. One remaining uncertainty is how well the membranes used for electrodialysis would hold up following exposure to water that contains traces of oil or gas. “We need some lab-based characterization of the response,” McGovern says.
If the system works as well as this analysis suggests, it could not only provide significant savings in the amount of fresh water that needs to be diverted from agriculture, drinking water, or other uses, but it would also significantly reduce the volume of contaminated water that would need to be disposed of from these drilling sites.
“If you can close the cycle,” Lienhard says, “you can reduce or eliminate the burden of the need for fresh water.” This could be especially significant in major oil-producing areas such as Texas, which is already experiencing water scarcity, he says.
While electrodialysis technology is available now, Lienhard explains that this application would require the development of some new equipment.
Few people understand all the issues in keeping houses warm, people and supplies moving. For the coming decades hydraulic fracturing is going to be key for keeping the modern world working.
Khanh-Quang Tran, an associate professor at the Norwegian University of Science and Technology’s (NTNU) Department of Energy and Process Engineering turns 79% of kelp into bio-oil. Kelp, also known as seaweed, offers all of the advantages of a biofuel feedstock with the additional benefit of growing, not surprisingly, in the ocean.
Tran conducted preliminary studies using sugar kelp (Laminaria saccharina), which grows naturally along the Norwegian coast. The results have been published in the academic journal Algal Research.
Tran said, “What we are trying to do is to mimic natural processes to produce oil. However, while petroleum oil is produced naturally on a geologic time scale, we can do it in minutes.”
Tran heated the kelp in small quartz tube ‘reactors’ – which look like tiny sealed straws – containing a slurry made from the kelp biomass and water to 350º C (662º F) at a very high rate of 585º C (1085º F) per minute.
The technique, called fast hydrothermal liquefaction, gave Tran a bio-oil yield of 79% meaning 79% of the kelp biomass in the reactors was converted to bio-oil. A similar study in the UK using the same species of kelp yielded just 19%. The secret, Tran said, is the rapid heating.
Biofuel has long been seen as a promising way to help shift humankind towards a more sustainable and climate friendly lifestyle. The logic is simple: petroleum-like fuels made from crops or substances take up CO2 as they grow and release that same CO2 when they are burned, so they are essentially carbon-neutral.
Tran like others references the International Energy Agency (IEA) report “Tracking Clean Energy Progress 2014 that said biofuel production worldwide was 113 billion liters in 2013, and could reach 140 billion liters by 2018. But the IEA says biofuel production will need to grow 22-fold by 2025 to produce the amount of biofuel the world will need to keep global temperatures from rising more than the oft quoted mystical 2oC.
Like others Tran is trying to solve the biomass feedstock problem. It’s relatively easy to turn corn or sugar beets into ethanol that we can pump into our car’s fuel tanks. But using land that can produce human food biomass for fuel is more and more problematic as the world’s population climbs towards 8 billion and beyond.
To solve the arable land limits, biofuels are beginning to be produced from non-food biomass including agricultural residues, land-based energy crops such as fast-growing trees and grasses, and aquatic crops such as seaweed and microalgae.
However, all of these feedstocks have their challenges, especially those that are land based. At least part of the issue is the fact that crops for biofuel could potentially displace crops for food. But seaweed offers all of the advantages of a biofuel feedstock with the additional benefit of growing at sea.
Turning big pieces of slippery, salty kelp into biocrude is a challenge, too Many studies have used catalysts to help make the process go more quickly or easily But, catalysts are normally expensive and require catalyst recovery. The UK study noted above that resulted in a 19% yield used a catalyst in its process.
Tran said the advantage of his process is that it is relatively simple and does not need a catalyst. The high heating rate also results in a biocrude that has molecular properties that will make it easier to refine. But Tran’s experiments were what are called screening tests.
Tran worked with batch reactors that were small and not suitable for an industrial scale. “When you want to scale up the process you have to work with a flow reactor,” or a reactor with a continuous flow of reactants and products, he said. “I already have a very good idea for such a reactor.”
Even though the preliminary tests gave a yield of 79%, Tran believes he can improve the results even more. He’s now looking for industrial partners and additional funding to continue his research.
Hitting 79% in the first development step is a huge encouragement. It would be great if the funding for more research found its way to Tran. This is another example how important high temperature process heat is going to be in the future. Great ideas like this one are going to be extremely useful and will need other great ideas to mature as well.
October 16, 2014 | 4 Comments
The Lockheed Martin Skunk Works has built and tested a new lab sized “compact fusion reactor” (CFR). The Skunk Works has built on more than 60 years of fusion research and investment to develop an approach that offers a significant reduction in size compared to government sponsored efforts such as the ITER multinational effort based in France.
Tom McGuire, compact fusion lead for the Skunk Works’ Revolutionary Technology Programs said, “Our compact fusion concept combines several alternative magnetic confinement approaches, taking the best parts of each, and offers a 90 percent size reduction over previous concepts. The smaller size will allow us to design, build and test the CFR in less than a year.”
Currently in design-build-test cycles, with more cycles to go, the team anticipates being able to produce a prototype in five years. With each experiment they gain confidence and progress technically. The team will also be searching for partners to help further the technology.
Lockheed believes its scalable compact concept will also be small and practical enough for applications ranging from interplanetary spacecraft and commercial ships to city power stations, perhaps even bring back the nuclear-powered aircraft.
Research institutions, laboratories, privateers and companies around the world are also pursuing ideas for fusion power, but no one has graduated from the experimental stage. Lockheed believes it has a concept to get past the formidable “breakeven” line of producing more power than used. The firm also knows the knowledge and intellectual prowess to solve the oncoming problems is beyond its staff expertise. They’re going public its project with the aim of attracting partners, resources and additional researchers. A very smart management move and realistic self assessment.
The young team is led by the youthful Thomas McGuire, an aeronautical engineer in the Skunk Work’s Revolutionary Technology Programs unit. The current experiments use a stainless steel container for a containment vessel roughly the size of a business-jet engine that’s connected to sensors, injectors, a turbopump to generate an internal vacuum and a huge array of batteries.
To understand the Lockheed position for backing the team the fusion basics need covered. Fusion fuel destined for reactors that produce heat as the primary energy almost always make use of the hydrogen isotopes deuterium and tritium. The isotope gas is injected into an evacuated containment vessel where energy is added, usually by radio-frequency heating breaking it into ions and electrons, forming very hot plasma.
Plasma, like an electric arc or lightning is too hot for physical containment necessitating strong magnetic fields that prevent it from touching the sides of the vessel. When the confinement is sufficiently heated and pressurized the ions overcome their mutual repulsion, collide and fuse. The fusion creates helium-4, releasing a neutron per atom that carries the released energy kinetically through the confining magnetic fields. These neutrons along with the radiant energy heat the reactor wall where conventional heat exchange technology can be used to drive turbine electricity generators.
The CFR presents a new version of confinement, something like 20 times more effective than the tokamak used at ITER. The Lockheed CFR has a series of superconducting coils generating a new magnetic-field geometry in which the plasma is held within the broader confines of the entire reaction chamber. Superconducting magnets within the coils will generate a magnetic field around the outer border of the chamber.
McGuire explains, “So for us, instead of a bike tire expanding into air, we have something more like a tube that expands into an ever-stronger wall.” The system is therefore regulated by a self-tuning feedback mechanism, whereby the farther out the plasma goes, the stronger the magnetic field pushes back to contain it. The CFR is expected to have a beta limit ratio of one. “We should be able to go to 100% or beyond.”
Containment efficiency is key. The Lockheed CFR generates more power than a tokamak by a factor of 10, which in turn means for the same power output, the CFR can be 10 times smaller.
McGuire takes up this point with, “It’s one of the reasons we think it is feasible for development and future economics. Ten times smaller is the key. But on the physics side, it still has to work, and one of the reasons we think our physics will work is that we’ve been able to make an inherently stable configuration.” One of the main reasons for this stability is the positioning of the superconductor coils and shape of the magnetic field lines. “In our case, it is always in balance. So if you have less pressure, the plasma will be smaller and will always sit in this magnetic well.”
McGuire credits his predecessors saying the Lockheed design “takes the good parts of a lot of designs.” It includes the (efficient confinement of) high beta configuration, the use of magnetic field lines arranged into linear ring “cusps” to confine the plasma and “the engineering simplicity of an axisymmetric mirror.” The “axisymmetric mirror” is created by positioning zones of high magnetic field near each end of the vessel so that they reflect a significant fraction of plasma particles escaping along the axis of the CFR. “We also have a recirculation that is very similar to a Polywell concept,” he added, referring to another promising avenue of fusion power research.
The Lockheed group is well aware the CFR is barely out of the concept phase, and many key challenges remain before a viable prototype can be built. “We would like to get to a prototype in five generations. If we can meet our plan of doing a design-build-test generation every year, that will put us at about five years, and we’ve already shown we can do that in the lab, McGuire said.
If that works out as expected a prototype would demonstrate ignition conditions and the ability to run for upward of 10 sec. in a steady state after the injectors, which will be used to ignite the plasma, are turned off. “So it wouldn’t be at full power, like a working concept reactor, but basically just showing that all the physics work,” McGuire said.
So far the preliminary simulations and experimental results “have been very promising and positive,” McGuire said. “The latest is a magnetized ion confinement experiment, and preliminary measurements show the behavior looks like it is working correctly. We are starting with the plasma confinement, and that’s where we are putting most of our effort. One of the reasons we are becoming more vocal with our project is that we are building up our team as we start to tackle the other big problems. We need help and we want other people involved. It’s a global enterprise, and we are happy to be leaders in it.”
Like the other leaders such as EMC2, Tri-Alpha and Lawrenceville Plasma Physics the theory should work – if the materials science and the engineering can get to the pressure heat and ion velocity to fuse and release more energy than used.
Give Lockheed credit for staying with the hydrogen fuels, lighting off Boron aka Pb11 fuel will be much harder, and integrating into the existing grid and power generating field. Small and simple has its attractions and a practical realistic sense.
Lockheed also has a steel cable connection to military and congressional funding, suggesting that this project will go. It will also, unintended, generate intense interest and confidence in the theories and efforts of the technologies McGuire cherry picked to build his concept. These groups are going for Pb11 fueling as best can be seen so far because that fuel’s fusion main product of electrons can go directly to electricity.
Hot fusion could have two major breakthroughs in hydrogen isotope fuel and again in Pb11. All before ITER even powers up.
Scientists from Tohoku University in Japan have developed a new type of energy efficient flat light source based on carbon nanotubes. The new flat panel technology has a very low power consumption of around 0.1 Watt for every hour’s operation making them about a hundred times lower in energy consumption than an LED.
With only days having passed since the 2014 Nobel Prize in Physics was awarded for the last big step in light emitting diodes (LEDs) as the single most significant and disruptive energy-efficient lighting solution of today, researchers and scientists around the world continue to search for the even better light sources of tomorrow.
In paper published in the journal Review of Scientific Instruments, from AIP publishing, the Tohoku researchers detail the fabrication and optimization of the new device. (Available in full at this writing.) The technology is based on a phosphor screen and single-walled carbon nanotubes as electrodes in a diode structure. The result is like a field of conventional bulb’s tungsten filaments shrunk to microscopic proportions.
We seem to be entering the age of carbon based electronics. Electronics based on carbon, especially the carbon nanotubes (CNTs), are emerging as successors to silicon for making semiconductor materials. CNTs may enable a new generation of brighter, low-power, low-cost lighting devices that could challenge the dominance of light-emitting diodes (LEDs) in the future and help meet society’s ever-escalating demand for greener bulbs.
The Tohoku scientists assembled the device from a mixture liquid containing highly crystalline single-walled carbon nanotubes dispersed in an organic solvent mixed with a soap-like chemical known as a surfactant. Then, they “painted” the mixture onto the positive electrode or cathode, and scratched the surface with sandpaper to form a light panel capable of producing a large, stable and homogenous emission current with low energy consumption.
Norihiro Shimoi, the lead researcher and an associate professor of environmental studies at the Tohoku University said, “Our simple ‘diode’ panel could obtain high brightness efficiency of 60 Lumens per Watt, which holds excellent potential for a lighting device with low power consumption.”
Lumen per Watt describes brightness efficiency telling people how much light is being produced by a lighting source when consuming a unit of electrical energy. Lumens per Watt is an important index to compare the energy efficiency of different lighting devices, Shimoi explained.
Although the device has a diode-like structure, its light emitting system is not based on a diode system, which are made from layers of semiconductors, materials that act like a cross between a conductor and an insulator, the electrical properties of which can be controlled with the addition of impurities called dopants.
The new device has a luminescence system that functions more like an old type TV or computer monitor cathode ray tube, with carbon nanotubes acting as cathodes, and a phosphor screen in a vacuum cavity acting as the anode. Under a strong electric field, the cathode emits tight, high-speed beams of electrons through its sharp nanotube tips, a phenomenon called field emission. The electrons then fly through the vacuum in the cavity, and hit the phosphor screen making it glow.
Shimoi said , “We have found that a cathode with highly crystalline single-walled carbon nanotubes and an anode with the improved phosphor screen in our diode structure obtained no flicker field emission current and good brightness homogeneity.”
A field emission electron source entrances scientists’ attention due to its ability to provide intense electron beams that are about a thousand times denser than a conventional thermionic cathode (like filaments in an incandescent light bulb). The effect is field emission sources require much less power to operate and produce a much more directional and easily controllable stream of electrons.
In recent years, carbon nanotubes have emerged as a promising material of electron field emitters, because of their nano-scale needle shape and extraordinary properties of chemical stability, thermal conductivity and mechanical strength.
Shimoi explained highly crystalline single-walled carbon nanotubes (HCSWCNT) have nearly zero defects in the carbon network on the surface. “The resistance of cathode electrode with highly crystalline single-walled carbon nanotube is very low. Thus, the new flat-panel device has smaller energy loss compared with other current lighting devices, which can be used to make energy-efficient cathodes that with low power consumption,” he said.
“Many researchers have attempted to construct light sources with carbon nanotubes as field emitter,” Shimoi said. “But nobody has developed an equivalent and simpler lighting device.”
Shimoi pointed out the wet coating process is a low-cost but stable process to fabricate large-area and uniformly thin films is a major step for device manufacture. But the flat-plane emission device has the potential to provide a new approach to lighting in people’s lifestyle, cut energy needs and reduce carbon dioxide emissions to the atmosphere.
All the major light sources have made great strides. From Edison’s incandescent with the vast array of types today, fluorescents that also have developed into a wide range of uses and choices to LEDs just getting to mass market acceptance and yet to reach all the potential. Now there is another technology coming on. Lighting is going to be a very interesting field over the coming years.
Scientists from Nanyang Technological University, Singapore (NTU) have developed a new battery that can be recharged up to 70 percent in only 2 minutes time. The new battery technology also has a longer projected lifespan of over 20 years.
The NTU scientist’s next generation of lithium-ion batteries could enable electric vehicles to charge 20 times faster than the current technology. For electric vehicles the technology will also be able to do away with frequent battery replacements. The new battery will be able to endure more than 10,000 charging cycles – 20 times more than the current 500 cycles of today’s batteries.
This could mean the technology is the next big thing in battery technology. The breakthrough presents a wide-ranging impact on many industries, especially for electric vehicles which are currently inhibited by long recharge times of over 4 hours and the limited lifespan of the batteries.
NTU’s scientists replaced the traditional graphite used for the anode (negative pole) in lithium-ion batteries with a new gel material made from titanium dioxide, an abundant, cheap and safe material found in the soil. It is commonly used as a food additive or in sunscreen lotions to absorb harmful ultraviolet rays or as the coloring agent in white paint.
Naturally found in a spherical shape, the NTU scientists developed a simple method to turn titanium dioxide particles into tiny nanotubes that are a thousand times thinner than the diameter of a human hair. The nanostructure is what helps to speeds up the chemical reactions taking place in the new battery, allowing for super fast charging.
Invented by Associate Professor Chen Xiaodong from the School of Materials Science and Engineering at NTU Singapore, the science behind the formation of the new titanium dioxide gel was published in the latest issue of Advanced Materials.
NTU professor Rachid Yazami, who was the co-inventor of the lithium-graphite anode 34 years ago that is used in most lithium-ion batteries today offers a third party opinion that Prof Chen’s invention is the next big leap in battery technology. “While the cost of lithium-ion batteries has been significantly reduced and its performance improved since Sony commercialized it in 1991, the market is fast expanding towards new applications in electric mobility and energy storage,” said Professor Yazami.
Professor Yazami also added, “There is still room for improvement and one such key area is the power density – how much power can be stored in a certain amount of space – which directly relates to the fast charge ability. Ideally, the charge time for batteries in electric vehicles should be less than 15 minutes, which Prof Chen’s nanostructured anode has proven to do.”
Prof Yazami, who is Prof Chen’s colleague at NTU Singapore, is not part of the research project and is currently developing new types of batteries for electric vehicle applications at the Energy Research Institute at NTU.
Lithium-ion batteries usually use additives to bind the electrodes to the anode, which affects the speed in which electrons and ions can transfer in and out of the batteries. But Professor Chen’s new cross-linked titanium dioxide nanotube-based electrodes eliminate the need for these additives and can pack more energy into the same amount of space.
Professor Chen said, “Manufacturing this new nanotube gel is very easy. Titanium dioxide and sodium hydroxide are mixed together and stirred under a certain temperature. Battery manufacturers will find it easy to integrate our new gel into their current production processes.”
The research team will be applying for a Proof-of-Concept grant to build a large-scale battery prototype. The patented technology has already attracted interest from the industry. The technology is currently being licensed to a company and Prof Chen expects that the new generation of fast-charging batteries will hit the market in two years’ time. It holds a lot of potential in overcoming the longstanding power issues related to electro-mobility.
Professor Chen hits the main point with, “With our nanotechnology, electric cars would be able to increase their range dramatically with just five minutes of charging, which is on par with the time needed to pump petrol for current cars. Equally important, we can now drastically cut down the waste generated by disposed batteries, since our batteries last ten times longer than the current generation of lithium-ion batteries.”
Even more important is the long-life of the new battery also means drivers save on the cost of a battery replacement, which could cost over $5,000 US.
This all sounds too good to be true, but this team is a top rung research group with a record of pressing into practical problems garnering practical results.
A 20 year battery lifetime would offer the electric vehicle market a huge boost.