How R&D labs can avoid major setbacks when scaling emissions-based processes

Approximately 50,000 litres of synthetic emissions gases, such as nitrogen oxides (NO_X) and carbon dioxide, are used in lab-scale R&D processes across global industries each year. Dr Alexander Krajete explains the challenges posed by non-representative emissions samples and the danger of investing in huge projects without seeing the full picture

Since the Fukushima disaster of 2011 showed humanity’s over-reliance on nuclear and fossil fuels, the emissions gases that are accelerating climate change have been viewed in a different light. Rather than just damaging by-products, CO₂, NO_X, sulphur oxides (SO_X) and other gases are now viable raw materials for fuel precursors, active pharmaceutical ingredients (APIs), plastics and more.

For the highest-polluting industries, this provided a financial incentive to capture and limit Scope 1 emissions. Research and development programs quickly followed to find a way to monetise emissions. Accurate and scalable work at one stage is essential to make sure the next stage goes to plan.

The role of emissions gases in R&D

Combustion engines produce emissions gases when burning organic fuels. These gases are a complex mixture of pollutants: the vast majority are CO₂, NO_X, SO_X and particulate matter. However, there are many trace elements and compounds present too, such as ammonia and hydrogen sulphide.

NO_X contributes to smog and acid rain, reacts with other air pollutants to form ozone and can damage human respiratory systems. Despite this, NO_X is very useful in ammonia production, which is essential for agricultural fertiliser.

Currently, natural gas-derived methane is the main precursor used in agricultural fertiliser production. Cutting-edge regenerative techniques can recover NO_X from emissions gases and supply nitrate ions for fertiliser manufacturing, reducing or even eliminating the need for fossil fuels.

Compatibility of a catalytic system with its intended input, in this case emissions gases from chimneys and exhausts, is the most important requirement of an applied process. However, the majority use synthetic emissions gases when researching ways to scale up to the enormous throughput required for financial viability.

The problem with synthetic emissions gases

As addressed, gases emitted by combustion processes are complex. Burning organic mixtures invariably produces all kinds of compounds, some in trace quantities that cannot be reasonably accounted for by synthetic gas manufacturers. Unfortunately, tiny numbers do not mean tiny effects.

Undetected and unmeasured species such as ammonia, hydrogen sulphide, carbon monoxide, different oligomers and countless others can all wreak destruction on otherwise effective chemical processes.

When laboratory scientists come to the demonstration plant and industrial plant scales, and use real emissions gases from their company’s chimneys and exhausts, those unknown species ruin the reaction pathways. This damage has two modes.

The first and most expensive is destruction of the medium. Reactions like those mentioned rely on catalysts, often made with platinum and palladium, to lower the activation energy barrier. The presence and competition of contaminants for active site availability will lower the reactivity and inhibit the desired reaction, slowing down or ruining process development.

Sulphur, CO, organic oligomers, many species are all capable of poisoning the catalyst, irreversibly inhibiting active sites and rendering it useless.

The other problem that trace contaminants can cause is partial conversion of species within reagents and accumulation of impurities in products. For example, instead of full conversion of CO₂ to methanol, side reactions can form formic acid, carbon monoxide or methane that contaminate the methanol product.

Real emissions gases protect investment

The only reliable foundation for circular processes using emissions as raw materials is real emissions gases. By using these genuine samples, captured from exhaust pipes and chimneys, from the initial pilot reactions onwards, R&D teams can accurately predict scalability of their innovations.

Krajete uses two techniques to capture emissions from combustion processes of all kinds: non-pressurised sampling using large balloons and pressurised sampling using metal canisters. These each have strengths and weaknesses. The former provides an optimal basis for analysing gas composition by avoiding the condensation caused by compression.

Conversely, pressurised sampling enables collection of larger gas volumes, 10 to 50 litre scale, and easier transportation. Both technologies can be applied to a wide range of emissions sources, from vehicle and stationary engine exhausts to paper pulp, cement and steel factories. Krajete provides pressurised bottles of laboratory-grade emissions for accurate analysis.

Dr Alexander Krajete is founder and CEO of emissions treatment expert Krajete.