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Reducing CO2 in the maritime

industry with OASE®

Energy & Resources
Gas Treatment
OASE®
Reducing CO2 in the maritime industry with OASE®
International shipping is to become climate-neutral by 2050. Various technologies are being pursued to achieve this ambitious goal. One of these is carbon capture and storage on board. Gas treatment technology is one of the most advanced processes for separating carbon dioxide from gas streams. In order to remove the carbon dioxide produced from the engine exhaust gases, the most efficient gas treatment possible is essential. BASF has developed solutions for the purification of natural gas from great depths and the high seas (FLNG) as well as for the treatment of exhaust gas streams from power stations or industrial plants.

OASE blue is BASF’s gas treatment technology designed for CO2 capture application in flue gas, with low energy consumption, low solvent losses, and an exceptionally flexible operating range. 
  1. It is now to be used on ships for the first time
Extracting natural gas on the high seas and generally from greater depths using special ships is a relatively new process, and has opened up new opportunities for gas purification. Offshore LNG production and gas purification at sea are only just beginning. Studies have shown that the effects of wave motion on on-board equipment are difficult to control and predict. BASF recognized at a very early stage that the effects of sea and ship movements on the gas purification plant, among other things, are very significant.

Did you know?

History

The 80th meeting of the Marine Environment Protection Committee (MEPC) beginning of July 2023 set the tone. In this meeting, the International Maritime Organization’s (IMO) new strategy for reducing greenhouse gas emissions from maritime vessels was approved. The most important result: the revised climate protection goals for the shipping sector, which aim to achieve climate neutrality by around 2050 in line with the long-term temperature target set out in the Paris Agreement. The meeting also agreed intermediate goals for 2030 and 2040. By 2030, the total annual greenhouse gas emissions from the international maritime shipping sector are to be lowered by at least 20 percent compared to 2008 – and ideally by 30 percent. By 2040, greenhouse gas emissions are to be reduced by at least 70 percent from 2008 levels, with efforts made to achieve an 80 percent reduction.
Fig. 1: This figure shows an example of the key equipment used in a gas scrubbing process for the removal of CO2 at increased pressure, such as when purifying natural gases. In the absorption column (left-hand column), the gas to be purified flows from bottom to top, coming into contact with the scrubbing liquid in the countercurrent flow. The scrubbing liquid loaded with CO2 is unloaded in a decompression stage (center) and in a regeneration column (right) and is fed back into the absorption column. Source: BASF SE.
Why is Gas treatment important?
Gas treatment is indispensable when using natural gas and synthesis gas, as certain components need to be removed reliably before the gases are used. While pipeline gas may still contain detectable traces of carbon dioxide, LNG must be practically free of CO2 to avoid impairing the cryogenic liquefaction process. Carbon dioxide is particularly critical because it can freeze out and clog the liquefaction units, ultimately leading to plant failure. The limit concentration for CO2 before liquefaction is therefore less than 50 vol-ppm. Special technologies are now also available for flue gases, refinery exhaust gases and biogas.
How does it work?
This animated video (Figure 1) shows an example of the key equipment used in a gas treatment process for the removal of CO2 at increased pressure, such as when purifying natural gases. In the absorption column (left-hand column), the gas to be purified flows from bottom to top, coming into contact with the scrubbing liquid in the countercurrent flow. The scrubbing liquid loaded with CO2 is unloaded in a decompression stage (center) and in a regeneration column (right) and is fed back into the absorption column
Why is it so difficult to treat gas on ships?
Studies have shown that the effects of wave motion on on-board equipment are difficult to control and predict. Absorption columns are used here, through which the gas to be purified flows from bottom to top and is brought into contact with the scrubbing liquid in countercurrent flow. A range of equipment is conceivable for enhancing the mass transfer, including a variety of column trays, bulk solids on holding grids or structured packings (i.e., internals in the columns consisting of thin, corrugated and perforated metal sheets or wire meshes). An initial conclusion of BASF’s research was the insight that the structured packings produced the best results, because they not only enable intensive mass transfer between the gas and the scrubbing liquid, but also increase the level of operational reliability.
 
Fig. 2: This three-dimensional diagram shows the calculation result of BASF’s CFD model of the maldistribution of liquid as a function of the column height. The further the liquid from above runs down through the column internals, the greater the liquid maldistribution becomes. Source: BASF SE.
Computer model describes the effect of wave motion on the scrubbing process
The CFD (computational fluid dynamics) model (shown in Figure 2) was created to describe the effect of the inclination and motion on the flow of the liquid in the column with internals such as structured packings. As described above, sufficient contact between gas and liquid is essential to the design of absorption columns. The flow is influenced by gravity and inertial effects alongside the column geometry. The inertial effects of the liquid were included in the model. They can only be neglected to the extent that the force of gravity predominates, which is normally the case at average acceleration levels. However, the inertial effect increases with higher acceleration due to the more pronounced movement of the column or its increase in height. Under typical operating conditions, the liquid flow is controlled primarily by gravity, whereas the gas flow depends on the pressure difference. As a result, the column inclination primarily affects the liquid flow. Any liquid maldistribution therefore also results in gas maldistribution.
Market for Floating Liquefied Natural Gas (FLNG)
The International Energy Agency (IEA) estimates that global production of natural gas will see growth of around 30 percent by 2040. Many experts believe that FLNG technology will make a significant contribution to this. Natural gas production on the high seas and from great depths opens up deposits that were previously inaccessible. The market research and strategy consulting company Emergen Research (Canada) valued the global market for FLNG at approximately 19.1 billion US dollars in 2022. Annual growth is currently projected at 4.7 percent, with the revenue forecast for 2032 standing at 30.7 billion US dollars.  FLNG production would be inconceivable without gas treatment, which is why it is becoming increasingly important in view of the economic development in this field.
Laying the groundwork with OASE®
 
With its two lines of development on FLNG and flue gas purification, over the last few years the OASE team has been conducting important research that equips it well for the task of reducing carbon dioxide emissions in shipping. Gas treatment under the tough conditions found at sea and the progress made in stationary CCS both lay the groundwork for effectively combating carbon dioxide emissions from marine shipping. The existing OASE system offers an array of bespoke solutions – whether for synthesis gas, natural gas in the form of LNG or FLNG, flue and refinery gases or biogas.