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Strike up a conversation with Israel Wachs, and you'll find him enthusiastic and ready to talk about his latest project. You can't blame him. A chemical engineering professor at Lehigh University, Wachs has discovered a process that could help paper mills save millions of dollars a year by converting methanol, a pollutant, into formaldehyde, a useful product. Any chemical engineer would relish this.

But that doesn't explain all the giddiness. Wachs envisions taking his process a step further and applying it to other industries, and it has him speaking like an ecologist. He calls it an environmental solution that could change the business approach to making pulp from timber and help achieve sustainability.

For Wachs, 52, the journey to becoming a chemical engineering academic with a bent for industry and the environment began as he grew up in New York City. In high school, he became proficient in math and science, particularly chemistry. "My strongest interest was in combining chemistry with math, and chemical engineering is exactly that," he recalls. He attended City College of New York for a B.S. and then ventured west to Stanford for a master's and Ph.D., all in chemical engineering.

"I always had an interest in learning, teaching, and academia, but I felt incomplete in my education," Wachs says in explaining his next move. "I felt the one thing I lacked was a grounding in industrial chemical engineering." He went to work at Exxon Research and Engineering in New Jersey, regarded at the time as the best research lab in the country, especially in areas he had researched at Stanford. "It was a good opportunity to come back to the East Coast and also be in the best possible laboratory." His tenure there ran from 1977 to 1986. After that, the academic world beckoned. "Having both an industrial and academic background gave me a nice perspective." He started at Lehigh in 1987.

Along the way, Wachs developed an interest in heterogeneous catalysis and surface science, which in simpler terms means reactions at the interface between multiple phases such as a gas and solid. "I really enjoyed that because it's a very important area. Ninety percent of chemical processes have catalysts in them. Catalysis also has a large impact on our gross national product in America, as 20 percent of our GNP involves a product going through a catalyst," he relates. "I was interested in the fundamental aspects of it, which I find very exciting." Twenty five years ago, scientists had just begun to understand the fundamentals of catalysis. "So it was an opportunity to get involved in an area that was cutting edge research, and yet it had enormous impact."

Such an approach would ultimately lead Wachs to the pulp and paper industry to help solve a major headache. To make pulp, paper mills digest logs under intense heat and pressure with a caustic solution and sodium sulfide to accelerate the reaction. The process separates lignin, a resin that bonds the cell walls of plants, from cellulose, the material used to make paper, producing ethanol and sulfur compounds, called mercaptans, as byproducts. The lignin consists of methoxy, which results in the production of methanol. U.S. paper mills once released this and the foul-smelling mercaptans into rivers and streams, resulting in the killing of fish. The U.S. EPA identified the pulp and paper industry as the largest single source of methanol pollution.

In response, EPA passed a law in 1993 requiring paper companies to stop dumping methanol-laced water into waterways by April 15, 2001. The conventional method of treating methanol and mercaptans became incineration at 1,500 degrees F., a process requiring a fuel, usually natural gas or diesel fuel. With this, Wachs explains, "paper mills only convert an extremely bad pollutant to moderately bad pollutants, at a cost of a couple million dollars a year." Incineration yields carbon dioxide, which causes global warming, and ammonia and nitrates. Sodium sulfide converts to sulfur compounds such as sulfur dioxide. Burning consumes a lot of fuel, which results in even more carbon dioxide, sulfur, and nitrogen in the form of nitrous oxide. Sulfur dioxide and nitrous oxide contribute to acid rain, and the latter is also associated with ozone formation.

With no decent method available for disposing of methanol wastewater, Georgia-Pacific (G-P), the giant paper company, approached Wachs in 1994 to find a solution. He met with Andrew Gibson, then process improvement manager at G-P and a chemical engineering alumnus from Lehigh (he now heads Gibson Technologies in Atlanta). During a lunch with Gibson, Wachs came up with an idea for a catalytic solution and sketched it on a napkin. As Wachs recalls, "At the end, he says, 'Can I take this back to my company.'" G-P executives thought it a novel idea worth further investigating, and they offered to support a research program at Lehigh to explore its viability. "It was interesting having all these guys show up at your doorstep from that napkin at that luncheon."

Catalysts made of metal oxides and metallic silver existed for oxidizing methanol, but these wouldn't work in paper mills because they were deactivated by sulfur compounds and the high steam concentration in gas containing the methanol. Working with a catalyst manufacturer and Sukwon Choi, one of his graduate students, Wachs conducted experiments in microreactors at Lehigh's Zettlemoyer Center for Surface Studies using a catalyst of vanadium pentoxide on a titania support. Not only did his catalyst incinerate the waste streams to carbon dioxide and sulfur dioxide at about 600 degrees F., a big improvement from 1500 degrees, the catalyst remained effective.

The rapid catalytic reaction rate and total conversion to carbon dioxide and sulfur dioxide made Wachs suspect an intermediate reaction was taking place. So he slowed down the reaction and discovered that in the middle one of three steps, formaldehyde was forming at high concentrations. "This was the discovery of a new catalytic reaction previously unknown and a new way of making formaldehyde," he proclaims. Encouraged by this, G-P built a mobile pilot plant with catalysts loaded into a reactor, and Gibson ran tests with it for two years at a pulp mill in Brunswick, Georgia.

The success of Wachs' catalytic process opened his eyes to a realm of possibilities. "We can convert all these pollutants to valuable products. You can actually make money on this," he reports. Formaldehyde goes into making resins used in glue for particle board, a big industry. "In the catalytic process, I convert all the ammonia and the nitrous oxide to nitrogen and water. What could be better than that?" Sulfur comes out of the sulfur dioxide, but in concentrated form, so they can reuse it in the digestion process. Carbon dioxide emissions drop because doing the reaction catalytically results in an exothermic reaction that gives off heat, eliminating the need for fuel, and it produces steam that can be used elsewhere in the plant as process heat. And any remaining carbon ends up in formaldehyde resins.

In Wachs' words, "This was a major advance for the pulp and paper industry." Gibson estimates that a mill producing 2,000 tons a day of pulp would save between $500,000 and $1 million a year using the new method. Wachs says, "Rather than consuming energy, this process generates energy. I think we're looking at a process with positive economics of $1.5 million per year and no pollution being produced." The formaldehyde alone could amount to $1 million. And with about 150 pulp mills in the U.S. and Canada and 300 more worldwide, total savings could be staggering.

As the next step, G-P has begun negotiations with engineering and manufacturing firms to build a prototype plant to demonstrate the technology on a large commercial scale. It may turn into a joint effort with other companies, and G-P may license the technology. Wachs has already been contacted by a half dozen companies.

Wachs believes the new catalytic reaction can also be applied to other industries that have problems with methanol wastewater such as the chemical, natural gas, and petroleum industries. "I'm excited. It's not every engineer that gets to experience taking something like this and see it go this far and generate that much interest, not only in the industry it was intended for but other industries," he says. And his interest crosses into a different realm: "I think we've latched onto an interesting approach to solve environmental problems. It's a new way to look at old problems."

Earlier this year, the American Society of Engineering Educators selected Wachs to make a presentation to Congress on his technology as an example of engineering work done by academia. He titled it "Converting Pollution to Profits." That led to discussions with the National Science Foundation, who had him hold a workshop with leading engineers and scientists to explore applying his concept to other industries. They've identified about a dozen processes, which NSF plans to promote as research programs in universities.

How does Wachs assess the path his career has taken? "This whole thing is very exciting for me." And as his catalytic process becomes standard fare in pulp and paper plants in future years, his enthusiasm can only continue to grow.

Progressive Engineer
Editor: Tom Gibson
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©2004 Progressive Engineer