Carbon capture on board ships continues to attract attention with French-class firm Bureau Veritas reporting that it is working with one of Hong Kong’s largest shipowners, Wah Kwong, and Shanghai Qiyao Environmental Technology Co. ., a subsidiary of the Shanghai Marine Diesel Engine Research Institute, to study the feasibility of the technology. Once considered best suited for large land-based industrial sites, carbon capture is gaining increasing attention as a tool to meet new carbon intensity rules for existing vessels.
Carbon capture technology has been used in land-based industry for many years. According to BV, this is a mature technology. The International Energy Agency (IEA) reports that in 2021, a total of 40 million tonnes of CO2 were captured and stored at onshore sites, with this number expected to increase significantly in the coming years. However, as a marine application, certain challenges, including safety, layout and power consumption, must be addressed. There are also the challenges of balancing efficiency with the cost of operating the systems and the requirements for moving CO2 from temporary storage on ships to permanent storage or reuse applications.
Qiyao Environmental Technology reports that it has developed technology for CCS that has completed laboratory testing, achieving a total carbon capture rate of over 85%. They continue to work to optimize results while pointing out that the CCS unit can be designed for different types and sizes of vessels.
The CCS system mainly consists of an absorption unit, a separation unit, a compression unit, a refrigeration unit and a storage unit. The basic principle is that the organic amine compound solution reacts with the CO2 in the absorption unit, separating it from the rest of the exhaust gases. The dissolved carbon dioxide compound solution is desorbed at high temperature in the separation tower before the extracted carbon dioxide is compressed, purified and cooled to liquid carbon dioxide and stored in a low temperature storage tank.
The study will focus on two types of bulk carriers in operation in the Wah Kwong fleet. Based on the specific design parameters of the vessels, Qiyao Environmental Technology developed a custom design of CCS units for Wah Kwong and submitted relevant drawings. Further research will be conducted for tankers.
BV has reviewed the plans in accordance with applicable regulations and rules to ensure the safety of vessels and equipment, and that carbon emission reduction targets are effectively achieved during vessel operation. Design approval for the CCS unit is under review.
Last year, the Japanese “K” line in collaboration with Mitsubishi announced the first successful capture and the storage of CO2 on board one of its ships using a demonstrator. They continue to explore the use of the system while multiple research projects are also underway in Asia and Europe. A study of tankers last year revealed that the technology is costly to implement but doable. One of the approaches companies have explored is adapting current exhaust scrubbers to add the ability to remove and store CO2.
With the imminent launch of the IMO CII ratings, the challenge is growing for shipowners and operators to find technology that makes vessels in service viable. The goal is to develop technology capable of meeting the IMO’s CII 2030 targets.