PEMs Stack Up to the Competition
Hydrogen generators are being eyed as the key to a renewable energy future. But in laboratory research, they are already a common fixture.
The element hydrogen offers hope and headaches in equal measure. The most abundant element on the planet is also one of the most attractive for use as fuel. But because it is also the lightest element, it does not naturally occur in pure form. Hydrogen is so crucial in manufacturing, energy supply, and scientific research that new methods to improve production are being eagerly sought.
Hydrogen production is difficult. Generating the gas costs more energy than can be recovered from heat in combustion. And containing and storing this highly flammable gas has been a constant challenge as well.
The leading method of production is steam-methane reforming, which extracts hydrogen from methane gas. This is the leading process for generating hydrogen in large quantities, but produces carbon dioxide and carbon monoxide. Electrolysis is the other prevalent method, in which electricity applied to water separates hydrogen and oxygen atoms, yielding pure hydrogen and waste oxygen.
For research laboratories, these options traditionally meant relying on third-party gas producers to generate, store, and deliver hydrogen (and other gases) in tanks to be utilized as needed. This has created a well-established supply network that resembles a variety of petroleum-based fuels.
In recent years, however, electrolysis has emerged as a second option. Proton Onsite, a hydrogen energy and gas provider in Wallingford, Conn., uses electrolysis to manufacture on-site, high-purity gas generators called proton exchange membrane (PEMs) electrolyzers. They work by running a current through a solid polymer electrolyte. This electrolyte is a thin, specialized plastic membrane that is permeable to protons when saturated with water, but does not conduct electrons. The process of electrolysis draws a hydrogen ion (the “proton”) from deionized water and brings it through the membrane. Eventually, a number of ions combine at the other end of the membrane to produce hydrogen gas, leaving oxygen on the opposite side.
The Power of PEM
Electrolysis through proton exchange is not new. NASA first used the technology on a significant scale in its Gemini program in the 1960s. But only recently has PEM technology been looked to by the U.S. government and a variety of major foreign firms, such as Mitsubishi Industries, as the basis for a large-scale energy and transportation infrastructure.
As a result of breakthroughs by federally funded research efforts and the work of private industry, such as Proton Onsite, the market for components of PEMs and membrane electrode assemblies used in PEM fuel cells (PEMFC) is growing. The market analysis firm Transparency Market Research predicts a compounded growth of approximately 21.1% from 2012 to 2018, spurred by a general demand for reduced fossil fuel usage and lower carbon emissions. As the technology improves, major players in the fuel cell component marketplace will increase investments.
The R&D segment of the market now represents about 20% of Proton Onsite’s current business. Due to an array of research applications that need high-purity gas, Proton Onsite has developed a dozen different PEMs to suit applications ranging from liquid chromatography/mass spectrometry to atmospheric analysis.
Proton Onsite’s primary laboratory product is the HOGEN hydrogen generator, which provides ultrahigh-purity hydrogen as a carrier gas with consistent composition and predictable low levels of oxygen and nitrogen. The HOGEN GC hydrogen generator is a simpler, less expensive, and less complex PEM geared for gas chromatography. For larger laboratories, the HOGEN S Series 20 and 40 hydrogen generation systems can supply carrier and fuel gas for up to 200 gas chromatographs.
“Many of our clients work in laboratories and facilities that are engaged in R&D, ranging from analytical chemistry and mechanical engineering to meteorological studies. Essentially, we supply technology for any application that requires a constant, pure supply of hydrogen, nitrogen, or zero air,” says Dave Wolff, regional manager at Proton Onsite.
The growth in laboratory use can be explained by convenience. PEMs can replace the need to procure, manage, and secure traditional sources of delivered gas to the facility. Proton OnSites’ patented PEM electrolysis technology produces hydrogen at 200 psig or higher, without the need for mechanical compression, eliminating the need for high-pressure liquid hydrogen tanks or compressed gas storage.
Scientists and researchers typically require hydrogen with ultrahigh purity. They want the gas for fuel and as a reducing agent.
“The on-site gas generator supplies a benchtop by utilizing water, electricity, and air to produce the gases needed for analytical chemistry applications in most laboratories. Between 8 and 10% of facilities each year are moving from gas generated onsite versus delivered gas in cylinders, as the price for delivered gases continues to increase and on-site generated gas costs remain stable. Also, in the case of helium, which is a dwindling natural resource, on-site alternatives are being considered as the gas becomes scarcer,” says Wolff.
Proton Onsite also helps address a crucial question for laboratories being fitted-out for gas supply: centralized utility infrastructure, or a point-of-use approach?
“There are a lot of factors in deciding whether to opt for several smaller generators or one large centralized system,” says Wolff. “To determine what scale will work best for any R&D application, a facility manager must consider redundancy, security, and safety. A manager must also consider long-term needs for the application in question, as a centralized system would benefit an expanding operation. It’s all about economies of scale, so for a decision like this, foresight and a good grasp of the numbers is always the best tool for weighing the options.”
Another major selling point for Proton Onsite is safety. By producing gas at the point of use, facilities circumvent the potential hassle of handling gas-filled cylinders on a regular basis. These cylinders, which are heavy and, in the case of hydrogen, contain highly flammable gas at 2,200 psi, are frequently viewed as one of the more risk-prone features of a typical laboratory.
“With a gas generator, there is no need to employ people to continuously handle cumbersome and dangerous cylinders, and there are few safety codes to adhere to. I would say the best reason to choose an on-site source of gas is precisely because there is no need for extraordinary design or installation measures,” says Wolff.
However, hydrogen generation is not without risk factors. According to Wolff, air-exchange rates are a major factor in the safe implementation of Proton Onsite’s equipment in the laboratory environment. In the case of a hydrogen leak, he says, it is imperative that the amount of hydrogen-to-air in the mix remains low to help avoid levels that could cause ignition.
Proton Onsite’s generators are also affected by safety protocols, specifically NFPA, which specifies where and how hydrogen generators are installed. The introduction of NFPA 2, says Wolff, has allowed customers to more easily justify the use of hydrogen generators in the laboratory space.
“The NFPA 2 standard has a more complex approach to hydrogen-storage spacing and placement that depends on three factors, not just one: the amount of gaseous hydrogen stored, the storage pressure of the hydrogen, and the internal diameter of the pipe or tube on the hydrogen-storage vessel(s) that connect to the storage. The implementation of an on-site hydrogen generator provides facility managers with a much simpler and less costly hydrogen supply method,” he says.
In the past year, Proton Onsite has made two significant announcements that signaled the growing importance of PEM electrolyzers.
Last May, Proton Onsite said that a joint effort with the U.S. Department of Energy to engineer a PEM electrolyzer that can fuel a vehicle was successful. The new stack, they reported, safely generates hydrogen gas at 5,000 psi without the need for a compressor, and releases the outgoing oxygen gas at atmospheric pressure. This is enough pressure to power passenger vehicles equipped with fuel cells that burn hydrogen.
Then, in April of this year, Proton Onsite announced plans to develop a 1-MW hydrogen electrolyzer for the renewable energy storage market. After generation, the gas is stored and used as a fuel or other energy need. The company’s development efforts reduced the number of parts and the amount of precious metals used in the catalyst for its PEM electrolyzers, decreasing production costs by 40% over the past five years. It plans to make the new generator available to the commercial market in 2014.
The company’s goal, according to Mark Schiller, Proton Onsite’s vice president of business development, is nothing less than the creation of a technological foundation for an affordable and reliable hydrogen refueling infrastructure.