Methanol, or methyl alcohol (CH3OH), is the easiest of alcohols. Obtained for the first time in 1661 by the Irish chemist and physics Robert Boyle through the destructive distillation of wood. And since the 19th Century has been widely used in chemical industry for the production of thousands of products of daily use: construction materials, foams, resins, plastics, coatings, polyester and a countless number of pharmaceutical products. And, more recently, as a clean fuel.
The methanol international market is going through a phase of huge expansion, with a worldwide production estimated by the Methanol Institute in about 110 million tons per year, a daily demand of 200,000 tons. The global industry generates $55 billion each year, while creating over 90,000 jobs.
Today methanol is mainly produced from methane and especially from synthesis gas from coal gasification, by means of catalytic processes operating at moderate temperature (250-270 °C) and high pressure (50-100 bar).
However, the increasing attention to climate changes, the commitment of the Countries for the reduction of greenhouse gas emissions and the recent technology development – together with the cited growth of the international market – are gradually shifting the interest towards new environmental-friendly production pathways.
Conceptually, the solution is quite easy: producing renewable methanol. No longer from wood, nor from fossil fuels, but from carbon dioxide (CO2) and from hydrogen from renewable sources. This approach involves several advantages: CO2 can be recovered, becoming a resource instead of a problem. On the other hand, the use of the overproduction of electrical energy from non-programmable renewable sources (i.e. wind and sun) for the production of hydrogen and then methanol allows a chemical energy storage, thus contributing to the stabilization of the electric grids and to a further diffusion of renewable plants (now limited by grid stability issues).
In other words, methanol can be produced from the overproduction of renewable electrical energy (some 480 TWh per year in Europe, that means some 150 medium-scale conventional power plants).
Today or tomorrow?
The technologies are ready. Their reliability is now demonstrated with excellent results in Iceland, near Reykjavík, at the “George Olah Renewable Methanol Plant”. It is the first and most important commercial-scale plant for renewable methanol production, in operation since 2011 and managed by Carbon Recycling International (CRI). The unit converts every year some 5,500 tons of CO2 into 4,000 tons of methanol, sold in northern Europe. CO2 come from a natural source (a volcanic area), whereas hydrogen is produced from water using electrical energy from a geothermal power plant. That’s why methanol is sold by CRI with the commercial name of Vulcanol®.
The CRI’s George Olah Renewable Methanol Plant in Grindavik, near Reykjavík, Iceland (source: www.carbonrecycling.is, February 2019)
In a carbon-based circular economy system, the application sectors are countless. The CRI’s unit converts natural CO2 into methanol, but it is not possible everywhere. But everywhere a lot of anthropogenic CO2 deriving from the combustion of fossil fuels is emitted in the atmosphere: power generation plants and heavy industries (refineries, steel and cement plants, etc.) release every year million tons of CO2 that result in irreparable damage to the climate and the environment. With the new technologies, these wide concentrated emission points can be intercepted, capturing CO2 and making it available for its reuse and for the production of methanol (and other fuels and chemicals).
The advantage is obvious: methanol would be produced not from fossil fuels, but from CO2 (avoiding its emission in the atmosphere) and the exceeding electrical energy (which otherwise would be wasted, being produced when and where it cannot be used).
And, as mentioned, the potential applications are countless. If today fossil-derived methanol is the feedstock for a number of products, renewable methanol is expected to become the major energy carrier. Easy to be transported (differently from hydrogen), it can be used as clean fuel for heavy transports, now mainly based on fossil fuels. If cars can be driven by electric engines and batteries – shifting the emissions problem towards power generation plants – this cannot be reasonably done for shipping and aviation sectors, now based on oil-derived fuels with more than 300 million tons of CO2 emitted per year in Europe, according to the data published by Eurostat and the European Environmental Agency. In this context, renewable methanol can become the turning point, decoupling this sector from fossil fuels.
The Stena Germanica ferry, owned by the Swedish company Stena Line, fed with methanol. (Photo credit: Methanol.org)
The pathway has been now opened. The Swedish shipping company Stena Line has recently (2015) modified the “Stena Germanica” ferry, that can be fed with renewable methanol. And several other companies are evaluating similar initiatives.
So, what is missing for the development of renewable methanol as the energy carrier of the future? The key problem is of economic nature. The CRI’s example should not be misleading: the unit in Iceland works in an almost ideal situation, with concentrated CO2 that leaves the soil and with hydrogen produced thanks to an endless source of geothermal energy, with very limited production costs. But, indeed, capturing CO2 from flue gas from conventional power generation or industrial plants is still expensive. And the processes for the production of renewable methanol are still not very efficient. A great effort is still required to the scientific community – together with adequate incentives from the policy makers – to reduce production costs and improve plant performance, with the aim to make renewable methanol competitive with the fossil-derived one.
This is one of the aims of the Sotacarbo research, funded by the Regional Government of Sardinia within the “Centre of Excellence on Clean Energy” project. Advanced CO2 capture technologies are under development for potential application in both power generation and industrial sectors. And the development and optimization of advanced catalysts for the production of renewable methanol are currently in progress.
The results are very promising from the scientific point of view and from the industrial perspective. And the industrial interest for these results has been recently acknowledged by the Italian Ministry of Economic Development through the obtainment of an industrial patent (n. 102018000004130) for an efficient catalyst for the production of renewable methanol from CO2 and hydrogen. And several studies are ongoing on new materials and new technologies. APettinau