At CDTi, we’re always pushing the boundaries of what’s possible in emissions reduction. Recently, we took a deep dive into how our top-tier methane catalyst technology could transform the exhaust systems of large dual-fuel marine engines.

Here’s a look at what we discovered and why it matters.

The Urgency: IMO’s 2050 Emission Goals

The International Maritime Organization (IMO) has set an ambitious target: halve maritime greenhouse gas emissions by 2050. With more than two-thirds of new vessels expected to run on LNG, reducing emissions from dual-fuel engines is crucial.

However, methane slip—a significant emission from exhaust stacks, vents, and flares—threatens to negate these climate benefits.

Our study aimed to show how a methane oxidation catalyst could reduce methane slip by 50% under real-world conditions.

Optimizing Methane Abatement:

We embarked on this lab study with a clear set of goals:

• Mapping Catalyst Performance: We analyzed fresh catalyst performance across different space velocities and varying levels of Platinum Group Metals (PGM).
• System Size Optimization: We aimed to hit target performance levels while keeping costs as low as possible.
• Cost Estimation: We evaluated the financial feasibility of our systems.
• Methane Abatement Efficiency: We estimated how well our technology would reduce methane emissions at the beginning of operational life.
• Deterioration Factor Development: We created a metric to predict performance over the catalyst’s lifespan.

The Challenges:

Methane’s high stability means breaking its carbon-hydrogen bonds requires substantial activation energy, typically achieved through high temperatures or expensive PGMs. Large marine engines add another layer of complexity due to their size and the need for seamless integration.

CDTi’s Solution: Lean Methane Oxidation Catalyst

Drawing on three decades of experience in emissions reduction, we developed a Lean Methane Oxidation Catalyst tailored to the challenges of these large engines. This passive device fits into the exhaust flow of dual-fuel engines and operates efficiently within typical exhaust temperatures of 300°C to 500°C.

In order to rapidly develop and prove out the solution, we draw on our simulation lab to simulate exhaust conditions and iteratively test and develop a variety of solutions. Our testing protocol entails the following:

• Simulated Exhaust Flow: We used a synthetic gas blend to mimic real exhaust conditions across the ISO 8178 test’s five set points.
• Catalyst Performance Analysis: We placed a catalyst core in the flow, raised the temperature, and analyzed the gas composition exiting the catalyst core.
• Aging Simulation: The catalysts underwent 20-hour aging increments, each simulating 5,000 hours of service life.
• Chemical Degradation Testing: We exposed catalysts to Sulfur Dioxide to replicate in-service sulfur poisoning.

Key Findings:

Testing quickly led us to a catalyst solution that met the methane abatement goals; however, it is not enough to test fresh catalysts. We also have to simulate the harsh life these products will endure. They are exposed to not just high temperatures for thousands of hours, but also contamination and poisoning, which is particularly acute from sulfur found in fuel.

Taking our most promising solution, we exposed to an accelerated aging cycle in steps equivalent to 5000 hours of service. The catalyst held up well to this thermal degradation, so we moved on to the final challenge of chemical poisoning with SO2. As we expected, the catalyst was significantly masked by sulfur, leading to significantly reduced methane abatement. A simple lean recovery step was then conducted to demonstrate the easiest form of catalyst de-sulfation, showing some promise; however, it was clear that a more thorough de-sulfation process would be required.

Optimizing De-sulfation:

Implementing a net rich de-sulfation strategy involves creating an oxygen-free environment in the exhaust during typical engine operation, disassociating sulfur from the catalyst and significantly restoring its performance. Lab demonstration of this method proved highly effective, returning catalyst performance to almost pre-SO2 poison levels, a very compelling result.

Conclusion:

Our study demonstrates the potential of CDTi’s Methane Oxidation Catalyst to effectively reduce methane slip in dual-fuel marine engines. With IMO’s 2050 targets in mind, our technology could play a vital role in cutting maritime greenhouse gas emissions, ensuring cleaner, greener seas for the future.

Stay tuned for more updates on our innovative solutions in emissions reduction!