Is Coal Synjet in Your Future?

 

By Jan W. Steenblik, Technical Editor

March 2007

The next generation of airliners will embody decades of advances in aerodynamics, materials science, structures, and powerplant technology. They are expected to be the most efficient jet airliners ever built. But they will be powered, like generations of airliners before them, by gas turbine engines that convert kerosene to thrust.

Meanwhile, the end of the oil age is coming-exactly when, nobody knows for sure. U.S. oil production peaked around 1970 and has been declining ever since. Estimates of the date of global "peak oil" vary from the end of 2005 (that's right, already past) to sometime in the middle of this century. Meanwhile, global and domestic consumption of petroleum continues to rise. China's oil consumption, for example, rose 37 percent between 2004 and 2005.

Today, the United States imports 60.3 percent of the oil it uses, and that percentage is increasing. Some of that oil comes from the most violent, corrupt, and politically unstable nations on the planet. Natural disasters (such as Hurricane Katrina in 2005)join geopolitics in playing hob with oil production, reserves, and prices.

The North American airline industry lost billions of dollars in the last few years to, among other things, the unstable and skyrocketing cost of jet fuel. Airline managements, of course, turned to their employees to shoulder those costs.

Many minds are focused on how to increase U.S. energy independence (or, perhaps better said, energy security) and what to do about the dwindling supply and rising cost of the finite fossil fuel on which we are so dependent.

The much ballyhooed (but controversial) efforts to ramp up U.S. production of ethanol as an alternative fuel may help in surface transportation. Ethanol is not, however, a viable replacement for Jet A; among other reasons, ethanol does not have nearly the energy density of kerosene.

Proponents of coal-to-liquid fuels say the answer lies in our own backyard-producing synthetic jet fuel (synjet) from our abundant reserves of domestic coal, using coal-to-liquid-fuels technology (CLT), whose beginnings predate the airline industry.

Turning lumps of coal into liquid fuel involves two basic steps.

First, coal is ground into a fine powder and partly oxidized in a gasifier. Coal is rich in carbon, ranging from 50 to 95 percent by weight, depending on the type and quality of the coal. The gasification process yields a mixture of carbon monoxide and hydrogen gas. The mixture is called synthesis gas, or syngas.

The second step is liquefaction by the Fischer-Tropsch process, a catalyzed chemical reaction that converts the syngas to liquid hydrocarbons of various forms, plus water. The catalysts here are usually based on iron and cobalt.

The liquefaction technology is named after German scientists Franz Fischer and Hans Tropsch, who in 1923 invented the process (since modified and refined) to produce liquid fuels in petroleum-poor but coal-rich Germany. Both Germany and Japan used the Fischer-Tropsch process to produce ersatz fuels during World War II. South Africa used the process during its isolation from much of the world under apartheid-and still does: South African Airways has been using synjet blended with petroleum derived jet fuel for years.

The United States currently has 20 coal gasification operations, but none currently produces jet fuel. John W. Rich, Jr., president of Waste Management and Processors, Inc. (WMPI) and Gilberton Power Company, both in Schuylkill County, Pa., wants to be the first to do so. Rich has been working for 15 years to establish the first U.S. CLT plant, in West Mahanoy Township, Pa.

Rich wants to build the Gilberton Coal-to-Clean Fuels and Power Project to produce electricity, steam, and liquid fuels from anthracite waste coal, also called "culm." The culm has been pilling up in Rich's part of Pennsylvania for 200 years, and there's a lot. His co-generation plant uses it to make electricity.

The U.S. Department of Energy has selected the Gilberton project to demonstrate the integration of coal waste gasification and Fischer-Tropsch synthesis of liquid hydrocarbon fuels on a commercial scale. In 2000, DOE gave Rich a $7.7 million development grant and in 2003 a $100 million commitment toward commercialization of the technology.

Shell Global Solutions U.S. will provide the gasifier, and the Fischer-Tropsch technology will come from Sasol Syn-fuels International Ltd. of South Africa.

Rich hopes to complete construction in 3 years. Once up and running, the Gilberton plant is expected to produce about 5,034 barrels per day of zero sulfur, high-quality fuel stock. About half will be made into diesel fuel, which the state of Pennsylvania has committed to buy. This is the first such commitment by a state to foster energy independence. The rest of the fuel stock will be JP-8 jet fuel (the military version of Jet A) for the U.S. Department of Defense.

In September 2006, the U.S. Air Force conducted flight tests involving a B-52 that ran a blend of JP-8 and synjet in engines No. 7 and 8. The blend burned at about the same rate as JP-8, reduced particulate emissions by 20-40 percent, and caused no leakage in the test engines. Leakage is an issue because synjet, unlike petroleum-based fuels, does not contain aromatic carbon compounds that cause O-rings and gaskets to swell and prevent leaks.

The synjet used in the B-52 tests was made by Syntroleum Corp. of Tulsa Okla, via the Fischer-Tropsch process. However, Syntroleum used natural gas as the feedstock; natural gas production in the United States is flat or in decline. Syntroleum has since "mothballed" its small demonstration plant until it obtains new contracts.

Meanwhile, Rich is working hard to get his Gilberton plant built. He says that other countries-especially China, which is developing 22 gasification based plants in China and Mongolia, plus 1 in Louisiana-are scooping up CLT technology around the world and driving up its cost. In the last 3 years, the estimated cost to build the proposed Gilberton plant has jumped from $612 million to $800 million.

Perhaps an even bigger challenge: Critics of CLT technology say that full fuel-cycle greenhouse gas emissions for coal-based synfuels are equal to or greater than their petroleum-based equivalent. Although Fischer-Tropsch fuels are cleaner than traditional fuels, a tremendous amount of carbon dioxide-a significant greenhouse gas-is created as a by-product of the process.

The DOE environmental impact statement for the Gilberton Coal-to-Clean Fuels and Power project is under going final review. Rich said in late January that he expected it to be issued soon. A sticking issue for DOE has been the carbon dioxide that the Gilberton plant would release. Rich counters that the Gilberton project will be able to satisfy the DOE by using various means of carbon sequestration-capturing the carbon dioxide and storing or using it in some other way. Mitigation technologies are available for gasified-based technology that do not exist or are not feasible for petroleum-based refiners.

For example, Rich points out, "If your design around coal, you can switch to other feedstocks, including biomass, which is carbon-neutral. The plant at Buggenum, in the Netherlands uses the same kind of gasifier, and now 30 percent of its feed-stock comes from chicken manure. So after we get the plant up and running on coal, we can make the transition to biomass."

A CLT facility producing 30,000 barrels/day-six times the design goal for the Gilberton plant-could generate fuel for about $1 per finished gallon, Rich says.

Meanwhile, Rich has talked to the governors of several states about building CLT plants. The governor of Montana has been publicly enthusiastic about turning his state's considerable supply of coal into liquid fuels.

How much coal does the United States have? Again, estimates vary widely, but the experts agree: The United States has more coal (in barrels of oil equivalent) than the known reserves of oil worldwide. Estimates of how many years of coal we have left vary widely, but the numbers are in hundreds of years at current rates of use. Those lowly lumps just might buy us some time.