for Mobile Facilities

Science (July 11, 2010) — Chemical engineers at Purdue University have developed a new method to process agricultural waste and other biomass into biofuels, and they are proposing the creation of mobile processing plants that would rove the Midwest to produce the fuels.

“What’s important is that you can process all kinds of available biomass– wood chips, switch grass, corn stover, rice husks, wheat straw …,” said Rakesh Agrawal, the Winthrop E. Stone Distinguished Professor of Chemical Engineering.

The approach sidesteps a fundamental economic hurdle in biofuels: Transporting biomass is expensive because of its bulk volume, whereas liquid fuel from biomass is far more economical to transport, he said.

“Material like corn stover and wood chips has low energy density,” Agrawal said. “It makes more sense to process biomass into liquid fuel with a mobile platform and then take this fuel to a central refinery for further processing before using it in internal combustion engines.”

The new method, called fast-hydropyrolysis-hydrodeoxygenation, works by adding hydrogen into the biomass-processing reactor. The hydrogen for the mobile plants would be derived from natural gas or the biomass itself. However, Agrawal envisions the future use of solar power to produce the hydrogen by splitting water, making the new technology entirely renewable.

The method, which has the shortened moniker of H₂Bioil — pronounced H Two Bio Oil — has been studied extensively through modeling, and experiments are under way at Purdue to validate the concept.

Findings are detailed in a research paper appearing online in June in the journal Environmental Science & Technology. The paper was written by former chemical engineering doctoral student Navneet R. Singh, Agrawal, chemical engineering professor Fabio H. Ribeiro and W. Nicholas Delgass, the Maxine Spencer Nichols Professor of Chemical Engineering.

Agrawal, Ribeiro and Delgass are developing reactors and catalysts to experimentally demonstrate the concept. Another paper by Agrawal and Singh addressing various biofuels processes, including fast-hydropyrolysis-hydrodeoxygenation, also appeared in June in the Annual Review of Chemical and Biomolecular Engineering.

The Environmental Science & Technology paper outlines the process, showing how a portion of the biomass is used as a source of hydrogen to convert the remaining biomass to liquid fuel.

“Another major thrust of this research is to provide guidelines on the potential liquid-fuel yield from various self-contained processes and augmented processes, where part of the energy comes from non-biomass sources such as solar energy and fossil fuel such as natural gas,” said Singh, who is now a researcher working at Bayer CropScience.

The new method would produce about twice as much biofuel as current technologies when hydrogen is derived from natural gas and 1.5 times the liquid fuel when hydrogen is derived from a portion of the biomass itself.

Biomass along with hydrogen will be fed into a high-pressure reactor and subjected to extremely fast heating, rising to as hot as 500 degrees Celsius, or more than 900 degrees Fahrenheit in less than a second. The hydrogen containing gas is to be produced by “reforming” natural gas, with the hot exhaust directly fed into the biomass reactor.

“The biomass will break down into smaller molecules in the presence of hot hydrogen and suitable catalysts,” Agrawal said.”The reaction products will then be subsequently condensed into liquid oil for eventual use as fuel. The uncondensed light gases such as methane, carbon monoxide, hydrogen and carbon dioxide, are separated and recycled back to the biomass reactor and the reformer.”

Purdue has filed a patent application on the method.

The general concept of combining biomass and carbon-free hydrogen to increase the liquid fuel yield has been pioneered at Purdue. The researchers previously invented an approach called a “hybrid hydrogen-carbon process,” or H₂CAR.

Both H₂CAR and H₂Bioil use additional hydrogen to boost the liquid-fuel yield. However, H₂Bioil is more economical and mobile than H₂CAR, Singh said.

“It requires less hydrogen, making it more economical,” he said. “It is also less capital intensive than conventional processes and can be built on a smaller scale, which is one of the prerequisites for the conversion of the low-energy density biomass to liquid fuel. So H₂Bioil offers a solution for the interim time period, when crude oil prices might be higher but natural gas and biomass to supply hydrogen to the H₂Bioil process might be economically competitive.”

The research was funded by the U.S. Department of Energy, the National Science Foundation and the U.S. Air Force Office of Scientific Research, and is affiliated with the Energy Center at Purdue’s Discovery Park.

Accessed & published by Henry Sapiecha

Biological Engineers Generate

Natural Gas with Bacteria

October 1, 2006 — A new kind of waste digester uses two different strains of bacteria in different tanks. This would normally take place in the same environment, but microbiologists have now separated it into two stages that increases natural-gas production. The technology increases efficiency and can turn three tons of food scraps into enough energy to power 25 homes for a day.

DAVIS, Calif. — There’s a new twist on the old adage, one man’s trash is another man’s treasure. Now that trash may be another man’s power. Researchers in California are turning garbage into bio-gas that may one day provide the electricity in your home.

Trash could soon be powering your home. A new digester can transform it into energy. It uses two strains of bacteria to convert waste into bio-gas. Most digesters store both bacteria in the same tank, which makes the process unpredictable and slow. But not this digester.

“Zhang’s process takes the two bacteria and separates them into two separate environments,” Dave Konwinski, the director of OnSite Power Systems in Davis, Calif., tells DBIS.

This new and improved digester is the brain child of Biological Engineer Ruihong Zhang. She and her students at UC Davis first built its prototype in the lab. She’s thrilled her new technology is being put to use in the real world.

“It’s a new technology … So it’s like a child grow into adult,” she says.

The digester will turn three tons of food scraps into energy for 25 houses a day. But it’s not just for homes. The digester could be especially useful to fuel processing plants. It s scheduled to be up and running this fall. OnSite Power Systems plans to market it in several states in the next couple of years, including California, Wisconsin and Minnesota.

“We can actually scale a digester to fit their current operations, fill it right at their operations, take the waste stream into the digester, and the energy right back into the plant,” Konwinski says. “It will make a substantial dent in our current energy requirement for petroleum.”

It’s a win-win-win situation for the environment, industry and consumers.

BACKGROUND: Environmental engineers at the University of California, Davis, are building a full-scale anaerobic digester that can convert any type of solid organic waste into electricity — even leftovers from restaurants. The system is part of the $100,000 Sacramento Municipal Utility District (SMUD pilot project), but an even larger digester system is being put into place in San Francisco.

HOW IT WORKS: In the process, food waste is collected from restaurants and institutions and then fed to bacteria that thrive in low-oxygen environments. It’s called anaerobic digestion, a naturally occurring process of decomposition. One type of bacteria turns carbohydrates into simple sugars, amino acids and fatty acids. A second group of bacteria eats those compounds and turns them into hydrogen gas, carbon dioxide, and acetic acid — the primary component of vinegar. Then a third group of bacteria takes those broken-down compounds and turns them into methane and carbon dioxide. Between 60 and 80 percent becomes methane. The methane can be used as fuel for an internal combustion engine that provides electricity.

TYPES OF DIGESTION: Anaerobic digestion is not the same thing as human digestion, since the type of bacteria that produce methane don’t live in the human digestive tract. Industrial anaerobic digesters can also harness this natural process to treat waste, provide heat, and increase nutrients in soil. They are most commonly used for sewage treatment and for managing animal waste.

BENEFITS: The goal of SMUD is to obtain 20 percent of its electricity from renewable sources such as wind, solar, and biodegradable matter by 2011. Currently SMUD derives 10 percent of its electricity from renewable sources, of which biomass accounts for 2.5 percent. The UC-Davis digester would keep food and other biodegradable waste out of landfills; food leftovers account for 18 percent of a landfill’s contents. One tone of leftover food can produce enough fuel to power 18 homes for one day.

WHAT ARE EXTREMOPHILES? An extremophile is any microbe that thrives in extreme conditions, such as temperature (extreme heat or cold), pressure, salinity, low oxygen environments, or high concentrations of hostile chemicals. Most extremophiles belong to a class known as archaeobacteria, but certain species of worm, crustacean and krill can also be considered extremophiles.

The Institute of Electrical and Electronics Engineers, Inc., contributed to the information

Sourced and published by Henry Sapiecha 7th June 2010

Hydrogen Gas Production

Cows are the answer

Aidan Turnbull reports on a recent visit to Electrawinds Biomass Mouscron, one of Belgium’s most advanced cogeneration plants based on biofuels. such as biomass and solar energy.

It’s incredible to think that tallow from rendered-down dead cows could be one of the major sustainable fuel sources behind 18MW of ‘green energy’ being produced by the Mouscron co-gen facility.
In terms of energy that’s enough to supply the needs of 44,000 families and still produce enough recoverable ‘waste’ heat to sell to industry facilities in the vicinity – and warm up local swimming pools too.
The other significant fact about the project, say the operators, is the
remarkable reliability and low wear rates the engines at Mouscron have achieved since their installation in 2006.
When the plant was first commissioned the concept of running engines on biofuel was pretty much uncharted territory.
But with their broad insensitivity to fuel quality, Mouscron’s large medium speed diesel engines, designed for heavy fuel oils, seem to cope readily with carbondioxide neutral fuels such as plant oils,
animal fats and various blends of wasteoils.
Typically, these are fuels which can cause considerable problems in high-speed engines with their more sensitive injection systems. But thanks to large mediumspeed diesel engines made by MAN Diesel,
they have effectively become part of the global warming solution.
The technology Electrawinds nv, headquartered in Ostend, Belgium, is currently the largest private player on the Belgian market for
renewable energy. Initially a provider of ‘green’ electricity, it began establishing wind energy projects, but soon began toinvest in other forms of renewable energ.

Its business strategy of combining wind, biomass and solar energy is unique in Belgium. Electrawinds now operates inItaly, France and Eastern-Europe. The story really begins In August 2005 when Electrawinds set up its first 13MW biofuel-based energy-generating plant in Ostend.
A template for later projects, the role of this facility was to convert animal and vegetable fats into sustainable energy.
Today, the Ostend plant has a capacity of Mouscron’s large medium speed
diesel engines, designed for heavy fuel oils, seem to cope readily
with carbon-dioxide neutral fuels such plant

Sourced and published by Henry Sapiecha 18th July 2009

Mitsubishi Heavy to Test CO2

Recovery from Coal-fired Flue Gas

Mitsubishi Heavy Industries Ltd (MHI) and Southern Company, a major US power company, will jointly launch a field test in 2011 to recover high-purity carbon dioxide (CO₂) from coal-fired flue gas.

The two companies will set up a CO₂ recovery demonstration plant, which is designed to be built at a medium-scale thermal power station in Alabama, the US. Based on the results of this demonstration plant, they will aim to commercialize the recovery plant in the future.

The field test will be subsidized by the US government. The demonstration plant will be constructed in Plant Barry, a coal-fired power station owned by Southern’s subsidiary Alabama Power. Recovered CO₂ will be compressed and stored in an aquifer deep underground.

The demonstration plant is composed of various facilities such as those for pre-processing, CO₂ absorption/reclamation (absorption and reclamation towers) and CO₂ injection. The plant will recover 500t of CO₂ per day (equivalent to that produced when 25,000kW electricity is generated). The recovery rate is 90% or higher. The purity of recovered CO₂ is expected to be 99.9%.

The recovery process is as follows. Coal-fired flue gas contains not only CO₂ but also ‘impurities’ such as SOx, NOx, heavy metals and halogen compounds. These impurities are removed as much as possible in the pre-processing facilities, and the flue gas is cooled to near room temperature.

Flue gas with most impurities removed is taken into the absorption tower. Inside the tower, the gas is brought into contact with an absorbing solution so that only CO₂ is absorbed into the solution. The solvent, “KS-1,” is an amine-based material co-developed by MHI and Kansai Electric Power Co Inc.

Next, the solution containing CO₂ is sent to the reclamation tower, where CO₂ and the solution are separated from each other by heating. Then, CO₂ is recovered, and the solution is recycled.

MHI has already commercialized a system to recover CO₂ from natural gas-fired flue gas. But, in order to apply this system to coal-fired flue gas, an additional process is required to remove heavy metals and halogen compounds because the impurities contained in natural gas-fired flue gas are only SOx and NOx.

Electric Power Development Co Ltd is also testing a CO₂ recovery plant for coal-fired flue gas at its Matsushima Thermal Power Plant. However, the amount of CO₂ recovered at the plant is only 10t per day. Therefore, a field test needs to be carried out using a larger scale plant for commercialization.

In addition to the field test announced this time, MHI is planning to construct a demonstration plant with a recovery capacity of 3,000t per day in the UK and intends to start trial operations in 2015.

Sourced and published by Henry Sapiecha 1st July 2009