Turning captured carbon into e-methanol offers a new revenue stream for pulp mills

This means e-methanol can be used both as a shipping fuel and as a chemical feedstock – two applications the World Economic Forum has identified as central to the wider decarbonization challenge. Currently, global shipping accounts for around 3% of CO₂ emissions, a figure with the potential to climb higher. And the chemicals industry, which depends on methanol as a precursor to a huge range of products, faces similar pressure to clean up its supply chain.

Pulp mills have the potential to play a critical part in the move towards wider-scale production of e-methanol. That’s because the biogenic CO₂ generated in pulp production is especially well-suited as a feedstock for e-methanol production, turning what was previously wasted emissions into a commercially viable renewable fuel stream.

And ANDRITZ has been at the forefront of testing carbon capture from a pulp mill to determine how the concept works at industrial scale, and how pulp producers can benefit. 

WHY PULP MILLS ARE THE RIGHT STARTING POINT

Biogenic CO₂ is released in pulp mills when biomass such as wood is processed – primarily in the recovery boiler, but also in the lime kiln and, in some cases, the power boiler. Because the raw material previously absorbed atmospheric CO₂ while it was growing, this CO₂ is considered carbon-neutral. It's also a particularly clean industrial source: with fewer contaminants than fossil-based emissions, it’s easier and more cost-effective to capture and use in chemical synthesis.  

A typical kraft pulp mill produces around 1.5 to 2 tonnes of biogenic CO₂ per tonne of pulp – a substantial and consistent supply, currently going largely unused. To validate the concept at industrial scale, ANDRITZ recently partnered with Metsä Group on a six-month pilot at the group's mill in Rauma, Finland, testing carbon capture directly from a recovery boiler, specifically targeting the Renewable Fuel of Non-Biological Origin (RFNBO) sector. 

TURNING FLUE GAS INTO FUEL

E-methanol production requires two main ingredients: CO₂ and hydrogen (H₂). The process begins by capturing CO₂ from the mill's flue gas stack. In parallel, pressurized alkaline electrolysis produces hydrogen by applying electricity to water and splitting it into hydrogen and oxygen. The two gases (CO₂ and H₂) are then combined in a catalytic reactor to produce crude methanol – which is cleaned to deliver pure methanol as the final product.

ANDRITZ has its own carbon capture portfolio, including amine-based, Hot Potassium Carbonate (HPC), and membrane technologies. HPC offers a lower steam demand and can make use of available electricity; membrane technology holds promise for smaller-scale applications but remains at the pilot stage. Crucially, the integration is designed not to disrupt core pulp production. Existing steam and water systems – typically not bottlenecks – are used to support the e-methanol process, meaning the existing pulp mill infrastructure can be used. The oxygen produced during electrolysis, meanwhile, is recycled back into the mill, with valuable applications in kraft pulp production, from oxy-enriched recovery boiler operation to the bleaching stages. 

WHY IT MATTERS?

The biggest operational challenge is the high electricity demand and the volatility of electricity prices. Methanol synthesis and distillation prefer steady operation, whereas electrolysis can ramp up and down quickly to follow lower electricity prices. Hybrid operation – combining steady mill-derived methanol streams with variable electrolysis output – helps to bridge that gap.

A recent FEED study conducted by ANDRITZ together with a Brazilian pulp mill customer set out to identify the lowest-cost concept for integrated e-methanol production. The study covered CO₂ capture, hydrogen production, methanol synthesis, and pulp mill integration. The outcome was clear: the strongest cost and efficiency advantages are achieved when e-methanol production is located directly at the CO₂ source.

Compared to remote concepts, co-location reduces costs, improves resource utilization, and minimizes risk. By integrating the e-methanol plant directly with the pulp mill, the project benefits from existing infrastructure, utilities, heat streams, and oxygen utilization. At the same time, CO₂ transportation costs and complexity are eliminated.

The study identified several key advantages:

• Up to 15% lower levelized cost of e-Methanol
• 7-10% higher pulp production through oxygen enrichment and optimized heat and steam integration
• Production costs below EUR 1,000 per metric ton of e-methanol (compared to a market price of around EUR 1,200 per metric ton)
• Lower CAPEX and OPEX through shared utilities and infrastructure
• Elimination of CO₂ transportation costs

As a result of studies like these, projects are already emerging in regions with low-cost green electricity, particularly the Nordics, parts of South America, and China. The environmental case, meanwhile, is compelling. At present, around 50% of the carbon in a pulp mill leaves via the stack. By capturing biogenic CO₂ that would otherwise be vented and putting it to productive use, the concept prevents emissions, reduces reliance on fossil methanol, and generates additional value from existing biomass without requiring any more harvesting of forests.
 

FROM BIOMASS PROCESSOR TO RENEWABLE FUEL PRODUCER

All of this means that the opportunities over the next 5–10 years are considerable. The technology is mature, the CO₂ volumes are large, the infrastructure is in place, and policy tailwinds are strengthening the commercial case. But there are of course significant barriers to overcome, such as high capital costs, the need for cheaper green electricity, and coordinated development of the wider supply chain.

Even so, our e-methanol concept is clear: pulp mills can be transformed from traditional biomass processors into integrated renewable fuel producers, closing the loop between pulp, power and fuel production. We believe this is a practical route towards decarbonizing the pulp industry – and other industrial sectors, such as shipping and chemicals – while generating meaningful new economic value.