A DCL oxidation catalyst for exhaust-gas cleaning has been field tested on a Wärtsilä 50 series dual-fuel engine during 5000 hours of continuous operation in an end-user power plant application. The engine has been designed for continuous operation on natural gas (NG), light fuel oil (LFO) as well as heavy fuel oil (HFO), thus giving the consumer a wide variety of fuelling options. All three fuels were used at some point during the 5000 hours field trial. These fuels have different properties such as differing levels of sulphur and ash contents that affect the abatement efficiencies of the oxidation catalyst. A detailed study was performed to understand the effect of different fuels, lube oil poisoning and long running hours on the abatement performance of the oxidation catalyst. The oxidation catalyst was equipped with sample cores that were exchanged during scheduled engine maintenance periods. This allowed parallel field and laboratory evaluation of the emissions abatement and the quantity of lube oil deposits on the catalyst at successive intervals of engine running hours. We will show that the combination of the dual fuel engine and the oxidation catalyst is very robust, even for the different fuels, and it gives low emissions.
Power plants with the facility to operate on different fuels, such as gas, light fuel oil and heavy fuel oil, have become a popular alternative to mono-fuel installations. Being able to change from gas to liquid fuel and back to gas, while continuously operating the plant, allows a very reliable and flexible operation on occasions when the gas supply is temporarily interrupted or uncertain.