The student team that just graduated inherited the project from another team of students that started it before graduating in 2013. They were: Joshua Callihan, Rosalva Chavez, Jonya Blahut, Risa Guysi and Holly Clarke.
That team won two first place awards in 2013 at the WERC: A Consortium for Environmental Education and Technology Development competition in Las Cruces, N.M. It's run by the Institute for Energy & the Environment (IEE).
When they tested the device it reduced the following harmful pollutants: carbon monoxide (CO) by 87 percent; nitrogen oxides (NOx) by 67 percent and particulate matter (PM) by 44 percent.
The device can be thought of as a three stage system. First, a filter captures the harmful pollutants. Then an ultra-fine spray of urea solution is dispersed into the exhaust stream. The urea spray primes the dirty air for the final stage, when a catalyst converts the harmful nitrogen oxide and ammonia into harmless nitrogen gas and water and releases them into the air.
The team that just graduated improved the original device in several ways:
They added a honeycombed substrate that solidifies the catalyst. Originally, the catalyst was in a powder form and was prone to blowing out when the lawnmower was being used. Harmful emissions will likely be further reduced because they will have more contact with the substrate. They changed the design of the device so it is essentially one piece of L-shaped stainless steel, instead of several pieces connected through fittings. Also, the new device doesn't stick out as far off the lawnmower. They eliminated the paper-thin quartz filter and replaced it with a stainless steel filter that should far outlast the quartz version. They added a muffler for sound reduction.
They expect the device w
|Contact: Sean Nealon|
University of California - Riverside