A team of Taiwanese researchers has combined industrial wastewater and petroleum oil to make a new fuel that could largely eliminate the costly treatment of industrial air emissions from boilers, is an environmentally-friendly way to treat industrial wastewater, and could increase fuel efficiency by 14%.
Worldwide, many industrial processes depend on steam boilers that are powered by what’s called heavy fuel oil (HFO). In the US, where coal and natural gas are plentiful, boilers are not typically run on HFO, but many homes in the Northeast US are still heated with furnaces that use HFO. These boilers are notorious for spewing out toxins into the environment when untreated.
Current laws require industrial boilers to be fitted with air pollution control devices that treat the emissions so they satisfy air quality regulations. At the same time, many of these industries produce a lot of wastewater that needs to be treated as well. All of this treatment adds up to a hefty bill, which, some would argue, stifles innovation and holds the economy back.
So what if we could kill two birds with one stone? What if the same wastewater coming out of these factories could be mixed with standard HFO to make a new type of fuel that burns much cleaner? We’d be satisfying the needs of our environment with the needs of industry for a beautiful win-win solution — exactly what the world needs more of.
A research team at National Cheng Kung University in Taiwan has set about to make this fantasy a reality. They’ve discovered that when they mix 80% HFO with 19.9% wastewater and 0.1% surfactant, then burn it in a boiler, carbon monoxide emissions are reduced by 84% compared to the emissions generated by burning standard heavy petroleum oil in the same boiler. Not only that, the new fuel also drastically reduces other emissions such as particulate matter, nitrogen oxides, sulfur dioxide, and volatile organics.
Emission Concentrations of SO2, CO, NOx, and PM in Flue Gases for Different Fuels
The addition of the wastewater to the oil causes microexplosions prior to ignition of the oil which, in turn, causes the oil to atomize into a fine vapor. This increases the surface area of the oil and leads to more complete combustion. The water also lowers the temperature of combustion of the entire mixture which also reduces pollution from nitrogen oxides.
Although the team has only focused on boiler applications to this point (understandably; there are about 6000 industrial boilers in Taiwan alone using 12 billion liters of HFO annually), there is no reason this type of fuel couldn’t be used in a standard diesel engine with a bit of modification.
You can find the research paper here (pay to download): DOI – 10.1021/es0717156
Image Credits: Image of wastewater treatment plant from stock.xchng. Table taken and modified from original research paper published in Environmental Science and Technology / Vol. 42, No. 1, 2008.