Strategy Paper: Chlorine Chemistry Will Hydrogen Become Chlorine Chemistry's Trump Card?

Author / Editor: Dominik Stephan / MA Alexander Stark

Can hydrogen play out as chlorine chemistry’s trump card? — Safe, clean, and sustainable — Eurochlor’s position paper on its Mid-Century Strategy for the chlorine industry reads like green buzzword bingo. Yet it’s clear that if the European Union wants to become carbon-neutral by 2050, it will have to take chlorine chemistry into account. It’s just as well that electrolysis provides a sought-after co-product.

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Chlorine production in Europe - in this case Neolyse Ibbenbüren - declined slightly in 2019 due to lower demand from the chemical industry.
Chlorine production in Europe - in this case Neolyse Ibbenbüren - declined slightly in 2019 due to lower demand from the chemical industry.
(Source: Neolyse Ibbenbüren)

Europe’s chlorine producers have achieved a complete shift in technology. Chlorine production using mercury, in 2014 still the method of choice in 22 % of plants, no longer plays any role today.

Over 83 % of chlor-alkali sites use energy-efficient and safe membrane processes, explains Eurochlor, the chlorine chemistry working group of the European Chemical Industry Council (Cefic) (a further 11.6 % of sites use diaphragm processes). This marks the successful completion of a years-long transformation process that some saw as a potential eliminator for European chlorine manufacture. In 2019, Europe produced 419 kilotons of chlorine. This is slightly less than in the previous year, but still above average in view of the overall decline in European chemical production.

But it is precisely this efficiency that is now becoming a problem for the industry: further significant savings through improved membrane processes are not to be expected, according to the association. In fact, modern processes are increasingly approaching thermodynamic limits – and despite all the technological leaps and digitization initiatives, those limits are fixed. In fact, after years of chlorine chemistry managing to get by with less and less electricity, the sector’s primary energy consumption has stagnated — there was even a slight increase from 2018 to 2019. Compared to 2011, primary energy consumption has fallen by almost 10 %, but this is largely related to the phase-out of mercury plants.

Hydrogen: A By-product Branches Out

If the European Union (EU) remains serious about its climate targets, things could get tight for the energy-intensive production of chlorine and the downstream chemicals for which it forms a key raw material. But the industry still has an ace up its sleeve that could make all the difference, in the form of hydrogen. The “miracle substance” is a by-product of chlorine electrolysis from brine. Hydrogen is undesirable in chlorine production because it reacts explosively with chlorine to form hydrogen chloride (you might remember this explosive mixture from school chemistry lessons). So the hydrogen has to be separated.

So far, hydrogen has mostly found profitable use at the major Verbund sites, either as a raw material or burned to produce heat. In fact, about 87 % of the hydrogen produced is currently “used” in one way or another, according to Cefic. In times of energy transition, however, this traditional pattern of use is set to change. Powered by “green” electricity, chlorine electrolysis could provide valuable green hydrogen for fuel cells and power-to-X processes virtually free of charge. As a bonus, the electrolysis plants could even be used to balance peak loads on the electricity grid, since chlorine production can be ramped up and down relatively uncritically — although Cefic has little faith in the vision of using chlorine production as a buffer for the transition to low-carbon energy.

It is logical that this trump card plays a leading role in Eurochlor’s “mid-century strategy”, since chlorine chemistry has to think about de-fossilization and climate neutrality just as much as the rest of the chemical industry. There is general agreement that chlorine will continue to play a role. The gas is an essential precursor for plastics, pharmaceuticals and pesticides, as well as being key to the production of drinking water, solar cells and batteries.

Does Chlorine Have a Future in Europe?

Unsurprisingly, Cefic continues to emphasize the importance of a strong chlorine industry for Europe and emphasizes that it must not fall behind its international competitors, either because of the energy transition or for any other reasons.

Since chlorine is toxic and harmful to the environment, efforts are being made — where possible — to dispense with long-distance transport and instead to produce chlorine within the framework of large integrated sites, close to the customer and on a just-in-time basis. Also part of the strategy is the recycling of waste materials containing chlorine, which is not only gaining in importance within the concept of the circular economy, but also reduces the production of toxic gases when waste is incinerated.

Another building block in the strategy of the chlorine experts is process safety. This includes not only the declared target of zero incidents, but also an intention to work together with all players along the chlorine value chain. Here, the industry still has homework to do, as in 2019 the number of incidents increased to 3.15 per million tons of chlorine produced (from 2.3 in 2018), as did lost-time incidents (2.8/million man-hours, compared to 1.26 in the previous year). In contrast, lost-time incidents for contractors and service providers declined significantly in this period.

Toward Emissions Neutrality With a New Leader

An old hand is to lead the association into the new, sustainable future: Wouter Bleukx, who heads the chlor-alkali business at chlor-vinyl producer Inovyn (in which the chlor-chemical activities of Solvay and Ineos were combined in 2015), was elected as the new Eurochlor chairman. Bleukx, who brings more than 20 years of experience in a wide range of chemical sectors, succeeds Jürgen Baune (Nouryon), who played a key role in shaping the association’s mid-century strategy.

Eurochlor thus symbolizes the dilemma facing numerous industries: Chlorine electrolysis itself is virtually emissions-neutral and the main raw material, common salt, is plentiful. But the sector’s enormous energy requirements can quickly become the Achilles’ heel for chlorine and chlorine products — after all, this energy would have to be supplied entirely from renewable sources by 2050. The alternative, however, would be to import PVC, pharmaceuticals and the like from outside the EU, with uncertain consequences for the economy and the environment. After all, one thing we must not forget despite all the debates about “chlorinated chicken”, chlorine-free paper or chlorine in drinking water: We cannot manage completely without chlorine.