Burnt potato inspiration for microwave technology

A small start-up company based in New Zealand's famous winemaking region is trying to revolutionise the way steel is made, and has signed a supply agreement with BlueScope's Kiwi operations to prove its technology commercially.

The company, called CarbonScape, says its "green coke" technology could reduce global carbon emissions significantly if implemented worldwide.

It uses microwave energy to concentrate the carbon in wood, creating in hours what takes millions of years for fossilised coal.

CarbonScape has just completed a crowdfunding-type capital raising, generating almost double the $400,000 it sought to build a production plant at Blenheim, in the Marlborough district of New Zealand's South Island.

CarbonScape has signed up to provide 9000 tonnes of the "green coke" to BlueScope's New Zealand Steel, based at Glenbrook, 40 kilometres south of Auckland.

With BlueScope's involvement, the "renewable carbon" technology could cause a significant drop in pollution from coke ovens at Port Kembla.

But the news would not be so good for the Illawarra's metallurgical coalmines.

Making coke is among the most intensively polluting processes involved in steelmaking.

It involves heating coal at temperatures around 1100 degrees Celsius, in a low-oxygen oven, in order to concentrate the carbon from the coal.

The resulting coke is used in blast furnace steelmaking.

Coke provides the carbon, and combined with iron and other materials, steel is made.

CarbonScape's process involves treating wood with microwave energy to concentrate the carbon.

While its reliance on timber - usually woodchips or sawdust - raises a question about its status as a green technology, CarbonScape says its plan is to use waste and scraps from the forestry industry, not fresh trees.

"CarbonScape's technology offers a low-cost method for producing a high specific fuel for the manufacture of steel products on-demand," the company's information on the crowdfunding website Snowball Effect said.

"The CarbonScape process transforms woody material [into] renewable high-grade solid fuel for steelmaking, using microwave energy to rapidly and efficiently convert the biomass into highly pure carbon.

"The resulting fuel has a highly desirable high carbon content, low sulphur and low nitrogen while the process offers a significant cost reduction, a fuel highly tailored for steel production, and environmental advantages compared with traditional methods."

CarbonScape says its processes use less energy than other cokemaking operations.

The supply agreement with NZ Steel was contingent upon CarbonScape completing construction of its plant, and successful testing of the final product in steelmaking.

CarbonScape says the idea for its microwave concentration technology came from one of its founders who, as a young boy, microwaved a potato for 40 minutes.

The microwave oven was destroyed but the potato became a black lump of carbon.


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