TECHNOLOGY: Used Oil Recycles Into Hydrogen Fuel

Bill Siuru

Will hydrogen be the next transportation fuel for the 21st century?

Many experts seem to think so. Besides creating less pollution when combusted, global availability makes hydrogen an attractive candidate for a future fuel alternative. Also, new technology exists for converting used motor oil and other renewable sources.

For example, hydrogen can be produced by electrolysis using electric power supplied by hydroelectric, nuclear, wind, geothermal or other types of power plants. In addition, hydrogen may be produced from natural gas, methanol, coal, oil shale, tar sands, biomass or waste petroleum products, including used motor oil.

Today, approximately 30 to 40 percent of used motor oil is recycled and reused either as a lubricant or in producing other petroleum-based products.

The remainder is burned in furnaces or power plants, producing heat and electrical energy, dumped into sewers or onto the ground. In the latter case, the oil, laden with carcinogenic trace metals could eventually contaminate water supplies.

Fortunately, a sulfur-tolerant, hydrogenation catalyst developed and demonstrated by the Institute of Gas Technology (IGT), Des Plaines, Ill., could increase the amounts of recycled used motor oil.

Sulfur-tolerance is necessary due to the substantial sulfur concentrations found in U.S. petroleum products like diesel fuel and gasoline. Sulfur, which seeps into internal combustion engine oil, can poison the reforming processes' catalytic materials, quickly rendering most catalysts inactive for hydrogen production.

Previously, IGT researchers demonstrated that a catalyst, originally developed for steam reforming of natural gas and coal effluent streams, could be used to produce hydrogen from several liquid feed stocks, including jet fuel, diesel fuel, gasoline and coal liquids.

In more recent experiments, when reacted with steam, a 100 percent conversion of waste motor oil was observed. The catalyst maintained high activity even in the presence of the oil's trace metal contaminants. However, heavy metals' fate in waste is still being investigated.

The IGT catalytic process has several advantages. First, it does not require prior cleaning of the used oil which greatly increases the cost and complexity of recycling. Since the cost of waste oil is negligible, this method of producing hydrogen is estimated to be $1 less per 1,000 scf than most other conventional hydrogen production techniques.

Although the IGT demonstration was limited to producing hydrogen in experimental quantities, the technique shows promise for future commercialization.