Science & TechClimate
Startup pitches a way to cut coal in blast furnaces by recycling their own exhaust
Helix Carbon says its electrolyser turns a furnace's carbon dioxide back into carbon monoxide, replacing a third of the coke and saving about $14 per tonne of iron.
Key points
- Helix Carbon's process turns blast furnace CO2 back into carbon monoxide for reuse.
- It aims to replace 33% of the coke a furnace burns at first.
- The company puts the saving at about $14 per tonne of iron.
A young climate technology company says it can make iron cheaper and cleaner by taking the carbon dioxide a blast furnace pumps out and turning it back into fuel for the same furnace.
Helix Carbon is one of 20 finalists in the Startup Battlefield competition at TechCrunch Disrupt, which opened in San Francisco on Tuesday. Its target is the blast furnace, where coke made from coal burns to produce carbon monoxide, the gas that strips oxygen from iron ore and leaves metal behind.
“Any attempt to decarbonize the steel industry without dealing with the blast furnace is not going to work,” said David Brown, the company’s co-founder and chief executive.
How it works
Helix captures the furnace’s carbon dioxide and runs it through an electrolyser, a device that uses electricity and a catalyst to pull one oxygen atom off each molecule. What comes out is carbon monoxide, which is injected back into the furnace, so the furnace needs less coke.
Brown said the equipment can handle the furnace’s full, raw exhaust stream, which most electrolysers cannot. “We don’t need to capture the CO2 first,” he said.
The company proposes to replace 33% of a producer’s coke at first, and estimates the saving at $14 per tonne of iron. “That may not seem like a lot, but margins in the iron industry are famously thin,” Brown said. Studies on the approach vary widely, with some suggesting 30% to 40% of coke could be replaced and others as much as 90%.
Brown argues the method suits an industry that keeps its plants for generations. “There are blast furnaces that have lived for over 100 years,” he said.
First customers
Helix has not named any customers or pilot sites, and has not given a figure for how much it could cut emissions. It plans to start with the specialty chemicals industry, where it expects revenue to come sooner, by making chemicals on site from waste gas.
“We just utilize it, and that opens up the door of making chemicals on-site right out of waste streams,” Brown said.