Work smarter not harder

Working harder does not necessarily get the job done more efficiently. Working smarter however, could mean more for less. With energy at a premium, new technology and sometimes the good old-fashioned application of existing technology could make a difference.

At the University of Minnesota (UoM), a team of researchers recently announced that they might have found a way to make a specialised type of molecular sieve that could make the production of gasoline, plastics and various chemicals more cost effective and energy efficient. Michael Tsapatsis in the university’s College of Science and Engineering leads the UoM team, which says that after 10 years of research it has published its findings in the journal “Science”.

The UoM says that its team has devised the means to develop, “Free-standing, ultra-thin zeolite nanosheets that, as thin films, can speed up the filtration process and require less energy.” It added that it has a provisional patent and is hoping to commercialise the technology. “In addition to research on new renewable fuels, chemicals and natural plastics, we also need to look at the production processes of these and other products we use now and try to find ways to save energy,” said Tsapatsis in a statement. The team estimates that in the process of separating mixed substances it can take up to 15% of the total energy consumption, some of which is wasted, due to process inefficiencies. When oil was plentiful and cheap this was not a consideration. However, times have changed and the there is an ongoing desire for more energy-efficient alternatives.

UoM said that a promising option for better, more energy-efficient separations is high-resolution molecular separation with membranes based on preferential absorption and/or sieving molecules with tiny differences in their size and shape. The team focused on crystals with molecular-sized pores (zeolite materials). Zeolites have been in use for many years as adsorbents and catalysts but the challenge remained in how to process the zeolite materials into extended sheets that remained intact. Michael Tsapatsis and his colleagues looked for a way to achieve a low-cost, scalable and reliable method of forming thin-film zeolite formations.

Using sound waves in a specialised centrifuge process the team say they have produced, “Carpets of flaky crystal-type nanosheets that are not only flat, but have just the right amount of thickness,” which can be used as a sieve, a membrane barrier and to separate molecules in research and industrial applications. “We think this discovery holds great promise in commercial applications,” said Kumar Varoon, a UoM chemical engineering and materials science PhD candidate and one of the primary authors of the paper published. “This material has good coverage and is very thin. It could significantly reduce production costs in refineries and save energy.”

The UoM says that the research in being funded by the US Department of Energy (DOE), including the Carbon Sequestration Programme and the Catalysis Centre for Energy Innovation, the National Science Foundation and a variety of UoM partners.

In Philadelphia, saving energy, this time with old technology as its base in a 3.6m-long steel box, is attracting attention. The Philadelphia Gas Works (PGW), founded in 1836, says that, with around 500,000 customers and over 6,000 miles of gas mains and service pipes, it is the largest municipally-owned gas utility in the US. Recently, the works installed an advanced gas-fired combined heat and power (CHP) microturbine system to its headquarters building ¬– the largest CHP system to be installed in the city thus far.

According to PGW, the natural gas-powered system will be able to generate around 40% of the building’s electricity needs while the waste heat from the system goes to operate a 40t absorption chiller to heat the building in the winter and cool it during the summer. “Producing electricity onsite will save PGW and our customers money, offset the equivalent amount from the Philadelphia electric grid and reduce harmful emissions in our region,” said Craig White, PGW’s president and CEO in a statement.

To fund the CHP project, PGW said that it obtained a US$456,000 matching grant from Philadelphia’s Green Energy Works! grant programme with the total cost reportedly coming in at around US$1.2m. According to the “Philadelphia Inquirer”, a major player in the microturbine CHP market, Capstone Turbine Corp. (Capstone) said that the average installed cost for a micro gas turbine works out to be between US$2500 to US$5000/kW and, at current gas prices, CHP systems could generate power at US$0.04/kWh, which equates to less than 50% of what an industrial power consumer would expect to pay. There seems to be an incentive for industrial and commercial users to go the CHP route with the possibility of installation investments being paid back in four years or less.

In November 2011, Capstone said that the Four Seasons Hotel Philadelphia was the first Philadelphia business to install a natural gas-powered CHP system. The company installed three C65 ICHP MicroTurbines on to the hotel’s roof and said that in the first two months of operation the hotel reduced its energy cost by over US$80,000. Capstone confirmed that its system provided the hotel with all of its hot water, 30% of its electricity and 15% of its heating and furthermore, that the project is expected to reduce the hotel’s total annual energy costs by 30%. “There is a great link: buy cheap gas, own your own turbine, and produce your own electricity,” said Marvin Dixon, director of engineering at Four Seasons Hotel Philadelphia in a statement. “Because we buy third-party transportation gas, we can shop around for the best rate. This has made electricity from the microturbines 20% cheaper than what we could get from the utility.”

With the Marcellus Shale gas fields currently producing prolifically, and along with other US shale plays helping to keep the price of natural gas low with no sign of a significant price jump anytime soon, it seems to be a “no brainer” not to go the microturbine CHP route.