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MEEF - Recycling Technologies  - previous page

Technology for plastic-to-diesel is new, untested

by Eiji Yamashita

HANFORD - Seven pounds of waste plastics for a gallon of ultra low-sulfur diesel. That's the concept Plastic Energy LLC touts with a plastic-to-diesel conversion plant it wants to build near Hanford.

A conversion technology called "catalytic cracking" is the key piece of the project, which makes diesel out of plastics theoretically through a no-burn thermal method.

Various literature indicates the technology is in use in Europe and Asia, but the company says what it plans in Hanford will be a step ahead of what already exists in the rest of the world.

But the fact that the technology is new and untested has opened up a controversy, eventually bringing the project to a halt.

With all the air district permits, including the right to construct, taken away in August, the company is trying to come up with a wholly new design and plans. George Larson, a partner for the company, says the data isn't there yet to prove the project's air emission safety but says he's hopeful to have it by spring.

Opposition groups, led by San Francisco-based Greenaction for Health and Environmental Justice, say they won't trust a company which tried to build the project without definitive air emission data for the first time around.

Safety of the project, as well as an approval procedure, was a main focus of discussion at a public forum on the Plastic Energy project that was held locally on Monday.

What's "catalytic cracking"?

In its April 2004 draft report "Life Cycle and Market Impact Assessment of Waste Conversion Technologies," the California Integrated Waste Management Board explains the technology in reference to Plastic Energy's plan and discusses a market background.

Catalytic cracking is a process that thermally converts discarded plastics into liquid and gas fuels. Shredded plastic feed stock is melted and mixed with catalyst, and gas is condensed and distilled into diesel and gasoline. Gas and gasoline are combusted in a gas turbine to generate heat and electricity, which makes the plant self-sustainable.

It's a commercial technology developed by H.SMARTech Inc., which formed Plastic Energy. This method takes polyolefin, such as grocery bags and film plastics, and rejects PVC, chlorinated plastic that releases dioxin when incinerated.

H.SMARTech first commercialized the process in 1998 in Zabrze, Poland, which by far is the world's largest catalytic cracking plant. Australia-based Ozmotech also has similar plants in Europe and Asia.

Can toxins fall through the cracks?

Residents and green activists point out a potential for harmful emissions from the plant, and an absence of data adds to their frustration.

" We know that there's a potential from any facility that deals with thermal process dealing with plastics which are loaded with a variety of toxic materials to have pollution," said Bradley Angel, executive director for Greenaction.

There are many pollutants that could possibly be incurred by a project involving combustion like the Plastic Energy plant, most troubling of which, an expert says, is dioxin.

" There's a bunch of things you have to worry about, but the big thing you have to worry about is dioxin. Why? Because dioxin is more carcinogenic than plutonium," said Jane Williams, an executive director of California Communities Against Toxics, of Kern County.
Environmentalists often make a connection between dioxin and incinerated PVC.

When he spoke in August, Henry Dwyer, a manager of the company, repeatedly ruled out a possibility of dioxin emission from the plant and said all PVCs will be turned away.

PVC is No. 3 plastic, which is non-recyclable. It is highly combustible and contains chlorine, which poses pollution concerns when burned and released into the air.

George Larson, a company partner, acknowledged the plant may not be able to completely keep out PVC but said it will have a safeguard against it.

" The front end segregation will keep PVC out of our process, most of which are recognizable white pipes ...," Larson said. "Certainly as has been noted, some may get through. But on the distillation side of our process, we have a dechlorinizer that will remove all chlorine from any fuels that are produced."

It is in the company's interest to keep PVC out of the feed stock because diesel fuel contaminated with chlorine cannot be sold.

Responding to a concern, the company also decided to burn gas from the Gas Company rather than using gasoline byproduct from the process, Larson said.

" Some concerned citizens said we don't have testing to confirm that gasoline which we'll use does not have any chlorine in it," Larson said. "We will submit a revised plan ... I do know for that section we'll use utility grade natural gas to power the electrical system until such time the necessary testing is done."

Is there emission at all?

Other potential pollutants incurred by the plastic treatment process are acid gases, metal additives and VOCs, or volatile organic compounds, Williams said.
In August, Dwyer said the project is a closed-loop system with "zero emission" during a conversion process.

But the draft assessment report by the California Integrated Waste Management Board says the technology creates emissions at various stages of the process.

" In addition to the diesel and electricity products, the process will have combustion emissions (criteria pollutants and toxics), VOC emissions from organic storage and drying operations ..." the report says, while noting that these emissions will be well below limits.

What the study concluded

The study evaluated the operation of three conversion technologies, including catalytic cracking, in terms of energy saving and air pollution.

Among the findings:

- Catalytic cracking would end up in significant offset of sulfur oxide because of its production of ultra low-sulfur fuel. But the report also noted that "there is a higher level of uncertainty regarding air pollution control requirements for [conversion technologies]."

- Data is insufficient to assess the technologies' potentials for emissions of dioxins and furans and other hazardous pollutants. When it comes to catalytic cracking, the report found no test data on emission factors for dioxins and furans, lead, cadmium, mercury and hydrochloric acid.

- Conversion technologies seem to do better in controlling greenhouse gas than landfills.

- They will reduce the amount of needed landfill space and increase diversion rates.

- These technologies will "likely result in greater local environmental burdens and a potential reduction in regional or global burdens."

Question of being "incidental"

Kings County Planning Agency Director Bill Zumwalt approved a one-year extension of a site plan review for the Plastic Energy project last month.

Concerned residents do not like the fact that this project gets excused from a much closer scrutiny involving an environmental impact report and a public hearing.

Zumwalt says site plan approved projects are exempt from such a review because they satisfy the general plan and zoning ordinances that already meet the state environmental requirement.

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