Gasification Process Key to Low Cost Diesel

Researchers at UC Riverside have unveiled a new process that can convert sewer sludge, wood, agricultural waste, plain old trash or even plastics into diesel oil for $1.00 a gallon. Viresco Energy, will pay $15 million for a pilot plant to be built in the next two years.

The the hydro-gasification conversion process, originally developed to produce clean-burning gases from coal has been adapted to be used with wet wastes.  Whereas traditional gasification uses oxygen, the new technique uses hydrogen and steam at nearly 1,500 degrees to break apart the feed stock into a gas made up of its molecular components.

After gasification, the resulting gas then go through a couple of other steps and It comes out as water, wax and diesel. There is little waste, up to 85 percent of the feed material becomes usable liquid fuel at the other end.

"The system requires no additional fuel or energy other than the chemical energy in the waste feed," said Colin Hackett, manager of the Alternative Fuels and Renewable Energy Program at UCR.   "This process has enormous potential for energy conversion from any wet-waste that contains carbon."

The program is conducted by the Bourns College of Engineering - Center for Environmental Research and Technology (CE-CERT) at UC Riverside.

This schematic diagram shows the component processes used in the Waste to Energy concept developed by UCR’s CE-CERT. Waste materials are ground into small particles (less than 1 mm in diameter) and mixed with water to form a slurry, which is then pumped into a steam generator that heats the mixture to about 700 C and 30 atmospheres pressure.

The superheated steam and hot waste particles are then mixed with hydrogen gas inside a long tubular reactor, known as a hydro-gasifier. Inside the hydro-gasifier, the hydrogen reacts with any carbon present in the waste particles and forms methane gas. The methane gas and the superheated steam are then fed into a second stage reactor, known as a steam reformer. In this reactor, the steam reacts with the methane to form hydrogen, carbon monoxide and carbon dioxide gases. Approximately half the hydrogen produced in the steam reformer is recycled back into the first stage hydro-gasifier, making it self-sustaining.

The remaining synthesis gases (hydrogen, carbon monoxide and methane) can either be used in a CE-CERT-developed variable gaseous fueled engine to produce electricity and process-heat, or sent on to a liquid fuel synthesizer designed to produce sulfur-free synthetic diesel fuel and recycled clean water. Molten salt heat transfer loops take heat away from the hydro-gasifier and fuel synthesis reactors and transfer it to the water steam generator and steam reformer reactor to make the system almost thermally self-sufficient. Thus carbonaceous waste and water feeds can be converted into fuels, process-heat, and recovered water in what is expected to be a series of self-sustaining processes.

The fuel has all the energy content of regular diesel without the sulfur, oxides of nitrogen and other components that led California to declare diesel fumes a cancer-causing substance.

Although the production cost may be about $1 a gallon, retail would be higher - but still far cheaper than current prices.

The process will be developed by a small company, Viresco Energy, that will pay $15 million for a pilot plant to be built in the next two years.  The pilot plant will be built at the CE-CERT campus on Columbia Avenue and should be able to convert 10 tons of waste per day into fuel. Construction is expected to be complete by mid-2008.

If the performance requirements are met, a full-scale, 400-ton-per-day facility would be built. A plant of that size could produce 16,000 gallons of diesel from biomass materials or 30,000 gallons a day from coal.

Viresco Energy is already talking with the city of Riverside about building a 400 ton-per-day plant near the city's sewage-treatment facility, where sewer sludge can be turned to fuel, said Jim Guthrie, president of Viresco.

Costly gasification has been the step in Gasification-Fischer Tropsch processes that keeps them from being adapted.  This type of process is more energy efficient than the biorefineries that are being used, but the capital cost of the process has been so high that the resulting product, which can be either ethanol, biodiesel or chemical feedstock, has been too expensive. If this gasification process proves economical it could pave the way to less expensive biofuels. 

Resources:

CE-CERT scientists developing process to convert wet bio-waste into energy as alternative to land application, UC Riverside Newsroom, April 3, 2002
From sludge to cheap and clean diesel, Andrew Silva, sbsun.com, Sept. 15, 2006

Comments

[mcr]

Lets see if this scales up as they claim in their pilot plant

(At USD $1 = £0.5258 BPS)

$1 per gallon ... ~ £0.17 per litre ...

The thing with gasification - as we're familiar with by now is large capexs (capital expenditures) to build the large facilities and the relatively low energy efficencies roughly 60% of traditional petrochemical (oil derived processes).

I'm quoting a presentation by Dr Richard Pike, Cheif Executive of the (British) Royal Society of Chemistry that I've been privalaged to sit in on...

"World-scale plants require reserves to support operation for project duration... Commercial attractiveness depends on the detail of cash-flow methodology ... Equipment costs are usually a small proportion of total costs; other costs show the demands placed on the host-country for a typical project Total project cost is approximately 4.8 times main equipment purchase cost Conversion of gas to GTL remains an energy-demanding process (cf LNG) - Typically yield of ~9 mscf/bbl Gas-to-liquids (GTL) 50-60%[chemical conversion process, typical]"

NOTE from mcr - these additional costs are usually in the middle east or other areas - away from the industrialised west where the market is.

His opinions were (for natural gas as a feed in his example) BUT bio-derived feeds here -

"GTL opportunities lie in decoupling petroleum product prices from feed costs by relying on cheap natural gas feed; this works provided product prices are high and gas prices low. Improving efficiencies and reducing non-fuel costs (including CAPEX) are also key elements "

"Economics of GTL will improve with reduced CAPEX and higher crude oil price environment (provided gas prices are low), but an important question remains on the next steps for the industry…"

He believes:
Commercial returns for small GTL plants at U.S.$1.00/Mscf require U.S$ 30/bbl oil

My own intereptation is - if the price of oil remains above $60 per barrel - then alternative (to natural gas) are feasible - but technology needs to be pushed further.... to get the overall economics better.

His own views of where the R&D efforts will focus are quiet interesting also...

I'll be keeping my eyes on this pilot plant described here

Thanks for pointing this out James!

[JP Elverding - the Netherlands]

I'm working on the realization of a plastics to diesel plant and hence have looked into costs and value of the produced diesel, to be operational in 2007 here in the Netherlands.

Naturally all alternatives to the usual, mostly fossil fuels have their prices and will wither with barrelprices under 60$ a barrel.
The major difference is that the environmental impact traditional fuel has when compared to this new kind of diesel. If we take the costs of pollution, healthcare and suffering in the equation, synthetic diesel is way more cheaper!

In the Netherlands fuels is heavily levvied, with a net price for dieselfuel of some 40 cents, a "pump-price" of approx. 1 euro per liter. If the levvies were mildly reduced for this cleaner kind diesel it would save many lives and make investors happy enough to invest in this and many other sources of sustainable energy.

Have a clean, wonderful day!