Environmental FAQs

Is it true that producing synthetic fuels from coal or petroleum coke makes their carbon footprint twice as dirty as conventional fuels?

No. Rentech’s technology, in combination with sequestration of carbon dioxide, will enable us to produce synthetic fuels facilities with lower carbon footprints than conventional fuels. We can achieve a lower greenhouse gas footprint though sequestration of the carbon and/or the use of biomass as co-feed. Unlike other uses of fossil fuels, the Rentech Process inherently captures CO₂ and other emissions. Having captured the emissions, we can then dispose of them safely, including sequestering of CO₂ produced during the process.

The United States Department of Energy recently published a life-cycle analysis of synthetic fuels that confirmed the results of a third-party life-cycle assessment of the carbon footprint of fuels to be produced at our proposed Natchez plant. Both studies concluded that the fuels from Fischer-Tropsch facilities would produce fewer carbon dioxide emissions than would result from fuels produced from conventional crude refining, even when coal or petroleum coke is the only feedstock. Combining biomass with fossil feedstocks can reduce the carbon footprint significantly beyond these levels.

How do RenDiesel^® and RenJet^® emissions compare to traditional fuel emissions?

Fuels produced by the Rentech Process emit significantly less particulates, sulfur oxides (SO_X) and nitrogen oxides (NO_X) than petroleum-based fuels. The Rentech Process produces biodegradable fuels that are cleaner burning than petroleum-derived fuels and either meet or exceed all applicable fuels and environmental standards. Any emissions created by our cleaner burning fuels are well within the requirements of all current and promulgated environmental rules applicable to diesel engines and are lower than those produced by ultra low sulfur diesel fuels. RenDiesel and RenJet have significantly lower amounts of regulated pollutants including reductions in NO_X, SO_X and cancer-causing particulates and unregulated pollutants such as polynuclear aromatics, aldehydes, and benzene. Rentech’s fuels also contain less carbon and therefore emits less CO₂ during combustion.

Fuels produced using the Rentech Process are virtually aromatic and sulfur free. What are the environmental benefits of that?

The move to ultra-low sulfur diesel fuel (ULSD) was driven primarily by the need to lower particulate emissions from diesel engines. As further reductions in diesel particulate emissions were mandated, diesel particulate traps (aka Diesel Particulate Filters—DPF) were introduced to physically trap particulates until burned off in a regeneration step. Mandated reductions in diesel engine NO_X emissions require a different trap, a NO_X trap, which can be poisoned by sulfur in the fuel. This trap is regenerated by using fuel or another reductant that converts NO_X to harmless nitrogen (N₂). RenDiesel fuel, with no sulfur content, reduces the amount of particulate matter (PM) that a trap needs to collect, increases the time between regeneration, and makes regeneration of the PM trap easier. RenDiesel is also an excellent reductant for NO_X traps as it contains more hydrogen than conventional fuels, which is the active agent in NO_X trap regeneration.

The reduced aromatics content of RenDiesel fuel contributes to reduced emissions in several ways as well. First, RenDiesel produces less soot from the engine reducing the amount that needs to be trapped by the DPF. This increases the efficiency of the DPF, resulting in further reductions in exhaust-out particulate emissions. Second, RenDiesel produces less engine-out NO_X emissions, which reduces the load on the NO_X trap. As less fuel is needed to convert NO_X to N₂, this should have a positive impact on fuel efficiency.