Filtration: The hidden hero in decarbonisation

While it is tempting to seek an overarching solution to the climate crisis, the reality is that no such standalone solution exists. Renewable energy production, carbon capture, recycling and EV battery production are key factors in the global pursuit of net zero emissions, but how do we optimise decarbonisation efficiency?

Experts at US-based Pall Corporation assert that the need to remove contaminants through appropriate filtration is vital to optimise decarbonisation efficiency.

Without the right technology, product purity and equipment efficiency are compromised – risking the need for remedial action and higher operational costs.

Why is purity crucial to green hydrogen expansion?

Stephanie Chioh, global market manager – Hydrogen, Pall Corporation: Green hydrogen is now a key component in many national net zero strategies, serving as a clean alternative fuel for energy-intensive industries, transportation and power stations.

The European Union, for instance, aims to produce 10 million tonnes of green hydrogen by the end of the decade, viewing it as essential to meet its goal of reducing greenhouse emissions by 55% by 2030. The US Department of Energy (DOE) has outlined its research and development (R&D) priorities to achieve the ambitious cost reduction targets for clean hydrogen production set by the Biden administration.

Renewable hydrogen production and storage, as well as technology for trucking applications, are among the key focus areas identified by the DOE’s Hydrogen and Fuel Cell Technologies Office in its Multiyear Program Plan.

Behind the scenes of these ambitious plans, the need to purify the hydrogen stream and remove solid, liquid and gas contaminants presents a significant technical challenge. There are stringent specifications around hydrogen gas purity: typically, concentrations between 2,000-6,000 ppm (parts per million) of oxygen and more than 2,000 ppm of water are seen contaminating the hydrogen produced using commercial alkaline electrolysis, while the maximum concentration allowed for fuel cell vehicles is 5 ppm of each under the ISO standard for hydrogen fuel quality.

Several filtration and separation steps must therefore be taken to meet these specifications and optimise production. Once the electrolysis has taken place, the liquid-gas mixture needs to be cooled, separated and compressed, with various separation techniques – involving gravity separators, mist eliminator pads, filter vane separators and liquid/ gas coalescers – being used to separate the liquid contaminants.

Solid contaminants originating from oxidation in process piping equipment such as pumps and compressors must also be eliminated by using regenerable and disposable gas filters in different micron ratings throughout the production process.

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Can we accelerate the use of biofuels?

Rory Duncan, global market manager – Oil and Gas, Pall Corporation: Transportation is responsible for approximately a quarter of global greenhouse gas emissions, so advanced biofuels have a key part to play in decarbonising this industry and providing a low-carbon alternative fuel for hard-to-abate sectors such as trucking, shipping and aviation.

The variation in feedstock quality into refineries for the production of liquid biofuels as well as the degradation of biomass during transportation and storage can cause severe damage to downstream equipment if left unfiltered. Challenges include pressure build up over the catalyst bed, damage to heat exchangers, as well as excess water. Properly selected filtration equipment along with liquid-liquid coalescers can help to overcome these challenges and extend run time performance.

Impurities that form during the production of biogas are also problematic and must be eliminated with efficient filtration and separation technology in order to avoid compressor corrosion, abrasion in rotating equipment and degradation of purification units. This allows biofuel producers to maintain production capacity through predictable and reliable operation.

What is the potential of CCUS?

Julien Plumail, global market manager – Carbon Capture, Pall Corporation: Carbon capture, utilisation and storage (CCUS) is playing an increasingly critical role in the global energy transition, particularly when it comes to decarbonising hard-to-abate sectors such as the cement and steel industries.

In 2023, government funding through ongoing subsidy programmes in the United States and Europe made more than $20 billion available to CCUS projects, and capacity announced for carbon capture by 2030 is due to increase by 35% and for carbon storage the increase is expected to be 70%.

As the number of CCUS projects ramp up, it is vital that any production challenges are effectively addressed, especially when it comes to dealing with contaminants. Post-combustion carbon capture involves removing carbon dioxide and particulate matter from flue gases. Contaminants can foul process equipment such as heat exchangers, reduce process efficiency and lead to losses in the amine-based solvent adsorption systems commonly used for extracting carbon dioxide from the flue gas.

Any deferment by dealing with pollutants later rather than earlier in the process increases the cost per tonne of carbon dioxide captured. CCUS infrastructure such as pipelines, transportation and storage containers are also vulnerable to contaminants, and it is therefore vital that appropriate filtration is in place across those aspects to limit any potential damage to equipment.

With the deployment of modern filtration technology, high carbon capture efficiency and reliable equipment operation can be maintained, maximising the removal of CO2 emissions.

Can chemical recycling of plastic waste advance the circular economy?

Serhat Oezeren, Chemicals and Polymers Market manager, Pall Corporation: As the natural world continues to be ravaged by more and more plastic waste, the need to improve the global recycling industry becomes increasingly critical. Only 9% of the world’s plastic waste is successfully recycled, with the majority being sent to landfill or simply incinerated, releasing harmful emissions into the atmosphere.

Multi-material plastic found in a lot of packaging cannot be recycled easily by traditional mechanical methods and this is largely responsible for low global recycling rates. Advanced chemical recycling –where mixed plastic waste materials are heated to temperatures of 400-600°C in the absence of oxygen – offers a solution to this problem by converting polymers into a mixture of liquid hydrocarbons (pyrolysis oil).

The oil can then be refined and used to manufacture new plastic products which have the same chemical structure as first-generation plastics and are therefore stronger than items created by mechanical recycling and remoulding. Pyrolysis oil can also be distilled to produce petroleum fractions such as naphtha, kerosene and gas oil which can be used in industrial equipment or blended with virgin fossil fuels for use in vehicles and machinery.

The production process, however, is vulnerable to impurities without proper filtration systems in place. Waste plastic pyrolysis oil contains unwanted particulate matter as well as a variety of additional contaminants such as organic gels and dispersed liquids which may contain dissolved contaminants.

This variety of contaminants needs to be removed to make the feedstock more suitable for downstream processing and to prevent the fouling of equipment and consequential downtime for maintenance. Appropriate filtration media and coalescer technologies play a vital role in removing these unwanted materials and at many stages of the recycling process.

Other advanced chemical routes such as, depolymerization (such as for the breakdown of biomass polymers into monomers) and solvent-based recycling (often used for multi-layer packaging) offer promising solutions for improving the recyclability of plastic waste and supporting the circular economy.

However, for the successful implementation of these technologies, there are still challenges on sustainable and economical filtration and purification.

Will EV battery production meet demand?

Anoop Suvarna, global manager – Battery Materials and Power Generation, Pall Corporation: As the electric vehicle market expands amid a global drive to decarbonise road transport, electric battery performance is becoming ever more crucial.

For most auto manufacturers, lithium-ion batteries remain the best option to power their vehicles due to their energy capacity, fast charging, low discharge rate and lifespan, but the manufacturing process is vulnerable to contamination issues.

For example, the purity and yield of the lithium and active materials that form the cathode – a key component of lithium-ion batteries – has a significant impact on how well a battery operates. Contaminants prevent optimal performance and must be eliminated through specialised filtration systems.   

Minimising contamination of the electrolyte and separator – another key component of lithium-ion batteries – must also be managed through filtration. The electrolyte and separator play an important role in facilitating the transfer of the ions between the anode and cathode, so maintaining its purity is vital to enable ionic conductivity, chemical and electrochemical stability, and thermal stability.  

Filtration plays a critical role in the process of recycling used lithium-ion batteries, separating valuable metals and facilitating their efficient recovery for reuse. By deploying effective filtration techniques in battery recycling, we can maximise the purity and recovery of valuable metals, contributing to a more sustainable and circular Li-ion battery economy.

In all these industries – renewable energy, CCUS, pyrolysis and EV batteries – advanced filtration is the unsung hero, enabling the smooth execution of a variety of processes. In the absence of the right filtration technology, producers are at the mercy of contaminants which can damage vital equipment, leading to decreases in operational efficiency and unforeseen costs.

Having optimal filtration and separation systems in place can alleviate those problems. At a macro scale, collaboration between governments and industries must be pursued if cohesive strategies for a net zero future are to come to fruition.