Focus on Research
Penn State Intercom......October 3, 2002

Desulfurization process works
at low temperatures

By A'ndrea Messer
Public Information

A process that removes organic sulfur from liquid fuels at low temperatures and ambient pressure without using hydrogen, may help refiners provide fuels for fuel cells and meet the upcoming government's ultra-clean fuel requirements, according to researchers.

"Currently, the U.S. Environmental Protection Agency allows 500 parts per million sulfur in diesel fuel and 350 parts per million in gasoline, but by 2006, the regulations will require only 15 parts per million sulfur in diesel and 30 parts per million in gasoline," said Chunsan Song, associate professor of fuel science and program coordinator, Clean Fuels and Catalysis, Penn State Energy Institute. "Long before that, however, we will need ultra-clean fuels for fuel cells."

Removing organic sulfur from hydrocarbon fuels is difficult because the sulfur is usually bound to aromatic compounds that exist together with non-sulfur aromatics based on toluene and naphthalene, compounds that fuel producers would like to remain in the fuel. When sulfur is removed with the aromatic compounds, further treatment of the sulfur- rich fraction becomes difficult.

Current methods of removing sulfur from liquid fuels use high temperatures and pressure and hydrogen gas. The new Penn State process, called SARS for Selective Adsorption for Removing Sulfur, goes at low temperatures and pressure and does not use hydrogen or other reactive gases.

"We have developed a process that selectively adsorbs organic sulfur on to a metal species," said Xiaoliang Ma, research associate, Penn State Energy Institute. "This method will not adsorb the coexisting aromatic compounds like benzene and naphthalene."

Diesel fuel and gasoline contain 20 to 30 percent aromatics but less than 1 percent sulfur, so removing the sulfur without removing the aromatics is difficult. The transition me tals or transition metal alloys used in the process selectively grab the sulfur. The active adsorbent is placed on a porous, non-reactive substrate that allows the greatest surface area for adsorption. Adsorption occurs when the sulfur molecules attach to the transition metals on the substrate and remain there separate from the fuel.

"The absorbent transition metals can clean 10 times their volume of fuel, but eventually the system becomes saturated with sulfur," according to Michael Sprague, graduate student in fuel science. "Solvent regeneration can restore activity."

Initially, there is an activation step to activate the absorbent materials, but after that, adsorption and regeneration of the absorbent are all that they need. The solvent can be reclaimed for future use, while the sulfur can be further processed.

The researchers hope that refineries can employ the process to remove sulfur and meet future ultra-clean fuel requirements and that those providing fuel for fuel cells can use the process to produce ultra clean fuel.

"Fuel cells need essentially zero sulfur fuel to operate," Song said. "Small adsorption sulfur removal systems might be used at gas stations on special clean fuel pumps for fuel cell vehicles to ensure that all sulfur is removed from the fuel. This SARS concept can also be used for on-board removal of sulfur from fuel for fuel cell system use."

The researchers would like to create a sulfur removal system for refineries that can be continuously regenerated. The U.S. Department of Energy supported this work through the DOE National Energy Technology Laboratory UCR program and the researchers have filed a provisional patent application.

A'ndrea Messer can be reached at aem1@psu.edu.

New Web site aimed at state's
agricultural marketing, commerce

The University has developed an interactive World Wide Web site for Pennsylvania agriculture that helps consumers, farmers and businesses find local producers of commodities and services. Called AgMap, the Web site can be found at http://agmap.psu.edu.

The site offers a searchable database that includes products grown or made around the Keystone State, allowing users to locate goods near their home, farm or business. The site includes complete descriptions of these products and provides information about how to find and contact the growers and producers directly.

All that is needed to use AgMap is a computer with Internet access and a Web browser. Behind the scenes, the Land Analysis Lab and the cooperative extension global positioning program maintains a Web-enabled database that is linked to a geographic information system, letting users easily search for farms, farm products and services based on how close they are to the user.

In addition, AgMap provides a communications network among agricultural businesses in Pennsylvania. This network allows producers to identify and contact other producers who offer similar products and services, which offers several benefits.

For information about AgMap, contact Rick Day at (814) 863-1615 or rday@psu.edu.

Research reveals
how cells protect
against stress

Stress happens, and over the eons all species of living things have evolved all sorts of ways to cope. Now, new research has revealed that organisms as diverse as humans and plants share a common set of stress-protection maneuvers that are choreographed by the metabolic machinery in their cells.

The research was led by Sarah M. Assmann, Waller professor of plant biology. Among the team's discoveries is that one cellular-processing step that originally was discovered in human cells also occurs in plant cells. "A human autoimmune disease and a disorder associated with breast cancer are known to result from a defect in this process," Assmann said.

The Assmann team studied a process triggered in plants by abscisic acid (ABA), a hormone that plants produce when they are stressed by drought. Assmann's lab discovered two years ago that the ABA hormone activates a type of protein called a kinase, which attaches phosphate groups to other proteins. The resulting cascade of events ultimately causes closure of microscopic pores on the plants' leaves in an effort to limit the loss of moisture.

In the present research, Assmann's group found that one of the targets of this ABA-activated kinase is a specific protein that binds RNA. Assmann's group further discovered that the ABA-induced phosphorylation of the RNA-binding protein caused its association with the RNA encoding dehydrin, a protein known to confer stress-resistance to plant cells.

In addition to giving researchers these and other important details about the processes that produce protective proteins, Assmann's research eventually could give farmers more control over the moisture content of their crops. "Our research points to a gene-regulation process that, if turned off after a crop matures, would assure that the pores on a plant's leaves would stay open, allowing it to dry more quickly in the field," Assmann explained. "In a crop like feed corn, for example, such control would be economically beneficial to farmers, who get a better price for their crop if it has reached its optimal moisture content."

In addition to Assmann, other members of the research team include Jiaxu Li, lead postdoctoral associate; postdoctoral associates Sona Pandey and Carl K.-Y. Ng, Ken-ichiro-Shimazaki and Toshinori Kinoshita at Kyushu University in Japan and Steven P. Gygi of Harvard Medical School.

Back