Catalysis 2022 issue

and hydrogen, without producing any CO 2 . The development of green hydrogen is moving fast. Although renewable energy output is variable, proton exchange membrane (PEM) electrolysers are engineered to cope with varying energy input. At the heart of every PEM electrolyser is a catalyst coated membrane (CCM), which is responsible for the produc- tion of hydrogen. These membranes consist of precisely engineered lay- ers of structured catalysts, typically platinum and iridium oxide. The catalysts are applied to solid mem- branes in a way that maximises potential hydrogen production. We design and manufacture high-per- formance CCMs at scale, building on decades of experience in fuel cells which use very similar technologies. Green hydrogen coming out of the electrolyser contains up to 1% oxy- gen, which is detrimental for most applications. However, oxygen can be economically removed by cata- lytic oxidation of hydrogen using our Puravoc Green catalysts. As a large secondary refiner of platinum group metals, we are also commit- ted to the creation of an efficient recycling system to help unlock future capacity and support a sus- tainable energy transition. Green hydrogen is available and oil refineries are starting to explore its use. One example is Shell’s Rhineland refinery in Germany, where green hydrogen is produced using a PEM electrolyser, powered by renewable electricity from off - shore wind. Green hydrogen will be used initially to decarbonise fuels production at the refinery. 2 Although green hydrogen is more expensive to produce than grey or blue hydrogen today, the key input – renewable electricity – is both increasing in capacity and reduc- ing in cost. What is beyond doubt is that green hydrogen will play an increasing role in the transition to net zero as the cost of renewable electricity continues to fall, and the cost of electrolysers reduces. Scope 3: Decarbonise fuels and chemicals production to reduce emissions from the products used Technologies are available to allow refineries to use bio- and waste

Hydrogen (H) pipeline Carbon dioxide (CO) pipeline

H from oshore wind

CO shipping

Industrial H user

H trains

H fuelling for transport

Manchester

CO storage

Liverpool

Industrial H user

H blending for homes and businesses

Flexible H power supply

Low carbon H production

Industrial CO capture

H trains

Industrial H user

Chester

H from solar and wind

Industrial CO capture

H blending for homes and businesses

Wrexham

Underground H storage

Figure 1 HyNet North West: Hydrogen hub based in England (UK) Image courtesy of HyNet

is captured and made available for either utilisation or storage. In our Blue Hydrogen Technology (LCH), an advanced reforming system com- prising an autothermal reformer (ATR)/gas-heated reformer (GHR) is combined with carbon capture. Green hydrogen uses renewable electricity to produce hydrogen without producing any CO 2 . Hydrogen produced via blue and green routes can be used to decar- bonise existing fuels and chemicals production. For more information, see Table 1. An oil refinery can replace imported electricity with low carbon hydro- gen that is used to decarbonise its energy requirements, and excess low carbon energy can be exported to nearby industry. When several industries are co-located, there is the potential to create a hydrogen hub. Scope 2: Reduce emissions associated with imported electricity and steam An example of a hydrogen hub is HyNet North West, based in England (UK). The heart of the pro- ject is Johnson Matthey’s LCH. This hydrogen hub will produce blue

hydrogen. This blue hydrogen will be used to replace fossil fuels used by industry and transportation, and the hydrogen will also be used to heat nearby homes. The by-product CO 2 captured from the LCH pro- cess and CO 2 captured from nearby factories will be safely stored in an

When several industries are co-

existing offshore well. The consor - tium includes Progressive Energy, Essar Oil (UK) Limited, ENI, Johnson Matthey, and other val - ued partners. This project is pro- gressing fast and will be onstream circa 2025. 1 The complexity of this ground-breaking project is illus- trated in Figure 1 . Green hydrogen goes a step fur- ther. Hydrogen is produced via the electrolysis of water using renew- able electricity (such as wind and solar). The water is split into oxygen located, there is the potential to create a hydrogen hub

24 Catalysis 2022