On board carbon capture and storage (CCS) as a means of reducing ships’ CO2 emissions is rapidly moving out of the “what if?” category, with exhaust gas scrubbers emerging as an answer to the capture part of the challenge.
Exhaust gas cleaning system specialists researching the possibility include Finland’s Langh Tech. It has successfully performed its first tests on board one of the vessels in sister company Langh Ship’s fleet, utilizing the existing Langh Tech hybrid scrubber installed on board.
Langh Tech has now conducted several preliminary tests of capturing the CO2 emitted by the vessel’s main engine using an existing Langh Tech closed loop SOx scrubber system.
In the tests, additional alkali was added to the scrubber closed loop process water in order to provoke a reaction between the alkali and CO2, effectively capturing the CO2 from the exhaust gas into the process water.
The setup of tests was limited by the capacity of the existing alkali pump, but positive results were observed even with only a slight increase in the alkali dosing. At a main engine load of approximately 85%, a 5% increase in alkali dosing (over normal level) was able to reduce the measured CO2 emission by 3.3%. At 40% main engine load, a CO2 emission reduction of nearly 7% was observed.
During the tests, the alkali consumption remained at a reasonable level, and the effect of this on the operating expenses of the vessel would remain practicable.
The results of the tests are regarded as a tentative proof of concept and additional tests with a further increased alkali feed will now be conducted to verify this.
The CO2 capture feature could be applied to any Langh Tech closed loop or hybrid scrubber systems with relatively low cost impact, with only minor changes to the existing scrubber system. The process could be performed with readily available alkali products such as NaOH and MgOH2, which are both already being used in many SOx scrubber processes.
Langh Tech is also researching methods of extracting the captured CO2 from the process water and looking for ways to store and/or utilize the captured CO2 efficiently both onboard vessels and upon possible discharge to shore.
Langh Tech is a green tech company that designs and manufactures SOx scrubber systems, water treatment systems for closed loop scrubbers and Ballast Water Management systems. It is one of the Langh companies, which also include Langh Ship, steel carriage and bulk container specialist Langh Cargo Solutions and Industrial and Ship Cleaning Services Hans Langh.