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How can we make industry more climate-friendly?


Hydrogen for industry – the climate-friendly way

The industry requires large quantities of hydrogen. Unfortunately, the current methods of generating hydrogen emit the greenhouse gas carbon dioxide. To generate hydrogen in a more climate-friendly manner we need highly specialised pumps.

Pie chart showing the use of hydrogen in the German chemical industry

A key base material in industry

Without hydrogen not much would be happening in industry: Hydrogen is needed for producing ammonia, for example, which is a base material for fertiliser. It is also required for producing methyl alcohol, the source material for chemicals such as formaldehyde or acetic acid. Crude oil refineries use it to refine mineral oil or for producing synthetic fuels.

Using hydrogen would also be an option for the steel industry to produce pig iron without any carbon dioxide emissions. This sector is actually responsible for the lion’s share of greenhouse gas emissions in industry: About 30 percent of Germany’s industrial emissions and about six percent of the country’s total emissions are generated by the steel industry.

Unfortunately, the generation of hydrogen also produces large quantities of carbon dioxide. It escapes to atmosphere and further drives global warming. What is the reason for so much CO₂ being released during hydrogen production?

Natural gas is the most important source of hydrogen

About 95 percent of the hydrogen used in industry today is so-called "grey" hydrogen. It is gained from natural gas – chemically referred to as "methane" – using the process of steam methane reforming (SMR). Here, hot water vapour is mixed with the natural gas under high pressure in the presence of a catalyst. A chain of reactions results in hydrogen and carbon dioxide.

Steam reforming has been further developed into autothermal reforming (ATR). This process generates the heat required by partial oxidation directly in the reaction chamber. A separate natural gas burner that burns methane purely for generating heat is not necessary. This makes the ATR method more energy-efficient than conventional steam methane reforming (SMR).
However, both these methods produce large quantities of carbon dioxide – about ten tonnes for every tonne of hydrogen generated. How can hydrogen be generated in a more environmentally friendly way?

Power and water produce green hydrogen

The most sustainable way of generating hydrogen is by electrolysis. In this method an electrolyser splits water (H₂O) with the help of electric power into its elements: hydrogen (H₂) and oxygen (O₂). If the power used is from renewable sources the hydrogen generated this way is climate-neutral. This is why it is called "green hydrogen".

A disadvantage of water electrolysis is its high energy consumption. Compared to steam reforming, which requires about 15 megawatt hours for generating one tonne of hydrogen, electrolysis uses 50 megawatt hours. This energy has to be provided from renewable sources to truly make hydrogen generation climate-neutral.

Infografik mit einem Vergleich von Bedarf und Produktion von Wasserstoff

Green hydrogen still needs some time

Green hydrogen would be the ideal solution. Unfortunately, it is not available in sufficient quantities – and it won’t be in the near future either. In Germany, for example, the coalition agreement provides for electrolysers with a total capacity of 10 gigawatts to be installed by 2030.

The quantity of hydrogen generated in this way would contain 30 terawatt hours (TWh) of energy. This is the equivalent of the power consumed by about 300,000 German households per year. Whether this expansion target will be met is unclear at this stage.

For 2030 a demand of 50 TWh as a minimum and 250 TWh as a maximum is estimated in the Hydrogen Compass of the Deutsche Akademie der Technikwissenschaften e. V. (acatech) [National Academy of Science and Engineering] and the Gesellschaft für Chemische Technik und Biotechnologie e. V. (DECHEMA) [society for chemical engineering and biotechnology]. This is a gap that needs to be addressed.

Blue hydrogen is a realistic interim solution

Until electrolysis processes for hydrogen generation have become more advanced and sufficient capacities are available for producing green hydrogen, "blue" hydrogen could serve as an interim solution. It is generated in the same way as conventional grey hydrogen by natural gas steam reforming. The difference is that the CO₂ produced in this process is separated using CCS (carbon capture and storage) technology instead of being released into the atmosphere. The CO₂ can then be transported on board a vessel or through a pipeline to underground storage facilities.

Depleted gas and oil reservoirs in the North Sea could be used for storing CO₂. Here, CO₂ could be pressurised and pressed into deep, porous sandstone layers, where it will react with the rock and mineralise in the long term. A cover layer of rocks with a thickness of several kilometres will make sure the carbon dioxide cannot escape from the storage reservoirs.

Blue hydrogen, which is available to the industry within a short timeframe, has benefitted from the many years of experience with CO₂ storage, as illustrated by the Sleipner project, 250 kilometres off the Norwegian coast.

This technology could serve as an interim solution to reach the climate targets faster in parallel to the infrastructure for green hydrogen being developed.

Infographic comparing the CO₂ emission per kilogram of hydrogen generated using different methods

How sustainable is blue hydrogen?

How climate-friendly is blue hydrogen? Studies have shown that it can be almost as sustainable as green hydrogen as long as two conditions are met: First of all, the technology used for reforming the natural gas has to enable separation of more than 90 percent of the carbon dioxide.

Such high separation rates are easier to achieve with the ATR process than with the SMR process as no additional burner is required for generating heat.

Secondly, leakage must be prevented when handling and transporting natural gas. Because of its high global warming potential, not more than one percent of the methane used must be emitted.

According to data of the International Energy Agency, this is already the case in countries such as Norway, the United Kingdom and the Netherlands. Under these conditions, the generation of blue hydrogen produces 2 to 3.5 kilograms of CO₂ equivalent per kilogram of hydrogen – values that are comparable to those of green hydrogen production.

KSB draws on decades of experience in generating hydrogen

For producing hydrogen as well as for collecting, transporting and storing CO₂ highly specialised pumps and valves are needed. They not only handle the pressurised liquefied carbon dioxide, they also pump absorbers such as amine solutions, which bind the gas – similar to sparkling water. In addition, CCS systems require process water and contain numerous cooling circuits in which water is circulated. Leakage has to be prevented and the systems have to be corrosion-resistant as dissolved carbon dioxide and amine solutions can be corrosive. It is further important to prevent low pressure zones from forming in the systems in which carbon dioxide would change from the liquid to the gaseous state. This requires a lot of practical experience.

KSB has got the advantage of knowing the chemical industry processes very well. We look back on decades of experience in generating grey hydrogen. This also benefits us when producing blue hydrogen. At a temporary test stand in Frankenthal we investigated the factors influencing the aggregation state of carbon dioxide in detail. This enabled us to find the most efficient pump and the right operating range for the corresponding task in the CCS process and to advise our customers accordingly.

This knowledge lead pays: "Our unique know-how in pump technology and global cooperation in local sales branches have resulted in an extraordinary year 2023 of blue decarbonisation projects for KSB," reports Renato Schioser Fragnani, Market Development Manager at KSB's Petrochemicals/Chemicals Market Area.

"Our customers recognise the value of our innovative technical solutions that contribute with tangible, sustainable solutions to the progression of industry reaching net zero emission."

Versatile pumps for extreme conditions

What pumps are typically used in CCS systems? In smaller systems that process between 10,000 and 100,000 tonnes of CO₂ per year, industrial companies frequently employ the Magnochem seal-less volute casing pump.

Its rotating shaft does not pass through the casing and therefore does not need to be sealed off, thus ruling out the risk of leakage at the seal. A magnetic coupling transmits the torque from the motor to the inside of the pump casing without any contact. This means the standardised chemical pump is hermetically sealed, providing protection against leakage.

The pump meets the highest of quality standards to ISO 5199. It is available in a large range of material variants. Its robust design is suitable for up to 40 bar. A version to API 685 is also on offer. Its great choice of hydraulic system sizes and magnetic couplings offers maximum flexibility.

Seal-less volute casing pump of the Magnochem type series
CHTR multistage high-pressure barrel-type pump to API 610 | KSB

Easy to service and reliable

In large systems that process about a million tonnes of CO₂ per year, pumps to industry standard API 610 / ISO 13709 are employed. For example, multistage between-bearings pumps such as CHTR (type BB5).

This pump set is designed with bearings on both sides of the impellers to distribute the load equally at high pressure or larger flow rates. It has been developed with maximum reliability and ease of maintenance in mind: An optimised design balances out any pressure differences and reduces the axial thrust along the shaft, which is one of the main factors affecting the wear of bearings and seals.

Strong rolling element bearings or segmental thrust bearings hold the impellers in axial position and absorb the remaining axial thrust. Mechanical seals and bearings can be serviced without the need to open the pump.

Safe valves for optimum flow control

Valves are just as important as pumps for producing blue hydrogen. Many companies opt for double-offset butterfly valves with a plastomer seat, such as DANAÏS 150. Plastomer materials are chemically resistant, enhance sealing properties and reduce wear compared to conventional seat materials.

Often the users of CCS systems also employ cage-guided single-seated control valves, which are fitted with a single valve disc supported by a cage or frame. This type of valve is often used in industrial plants when precise control of a fluid flow is required.

For liquefying carbon dioxide they use metal-seated butterfly valves made of stainless steel. The metal contact between the valve disc surface and the seat surface provides a tight shut-off and minimises the risk of leakage.

DANAÏS 150 double-offset butterfly valve

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