How does Carbon Capture technology work?

What is Carbon Capture technology and how does it work?

At its core, carbon capture technology is a process for removing CO₂ from emission sources and preparing it for safe downstream handling. The most established route is carbon capture and storage - CCS - where captured CO₂ is processed and transferred to permanent geological storage. In some projects, the CO₂ may instead be reused in industrial applications, in which case the term CCUS - carbon capture, utilisation and storage - is used.

When people ask, what is carbon capture technology and how does it work, the answer is broader than capture alone. A complete CCS chain includes:

• Capture of CO₂ from flue gas or process gas at the emission source

• Conditioning to remove unwanted moisture or impurities

• Compression and cooling to prepare the CO₂ for efficient transport

• Liquefaction where required for ship, truck or terminal handling

• Transfer through pumps, pipelines, loading systems and storage interfaces

• Permanent underground storage in suitable geological formations
  
  

DESMI’s role is centred on reliable flow handling through these stages. That includes pumps and systems for solvent circulation in capture plants, low-temperature transfer of liquefied CO₂, marine cargo handling and pumping requirements linked to storage and export infrastructure. In both industrial and marine CCS applications, dependable liquid handling is fundamental to uptime, energy performance and operational safety.

The carbon capture process in practice: capture, compression, liquefaction and storage

In most industrial projects, the process starts with post-combustion capture. Flue gas from a boiler, kiln, engine or process unit is first cooled and cleaned. Particulates, contaminants and excess moisture are managed upstream so that the capture system can operate under controlled conditions and downstream equipment is protected from corrosion, fouling or unstable performance.

The treated gas then enters an absorber, where a solvent - commonly an amine-based solvent in established systems - selectively binds CO₂. The CO₂-rich solvent is transferred to a stripper, where heat releases the captured CO₂ and regenerates the solvent for reuse. This loop depends on stable circulation rates, controlled temperatures and reliable pump performance across varying operating loads.

Once released from the solvent, the CO₂ is compressed in stages. Interstage cooling is typically used to manage temperature and reduce energy demand. Depending on the transport route and storage concept, the CO₂ is then cooled and conditioned further into a dense or liquid state. In many liquefied CO₂ applications, operating conditions fall within a range of roughly 20 to 30 bar, with temperatures around -20°C to -50°C, although exact conditions depend on system design, impurities and transport requirements.

After conditioning, the CO₂ can be routed to:

• Pipeline systems for onward transfer

• Storage tanks at terminals or hubs

• Ship loading systems for marine transport

• Truck filling systems for smaller-scale logistics

• Injection systems connected to permanent geological storage

Across these steps, pumping reliability matters in different ways. Solvent circulation pumps support stable absorber and stripper operation. Transfer pumps protect continuity during tank-to-tank, tank-to-ship or terminal-to-pipeline handling. Low NPSH performance becomes especially important where cryogenic or liquefied CO₂ is handled close to vapour pressure. Poor suction conditions can quickly affect capacity, phase stability and equipment life.

What carbon capture methods are used in industrial and marine applications?

Several carbon capture methods are available, but they are not equally suited to every sector. Technology selection depends on flue gas composition, CO₂ concentration, available energy, space constraints, integration complexity and the intended transport and storage route.

Post-combustion capture is currently the most established option for many industrial and marine applications. It is widely considered the leading route for retrofitting existing assets because it treats flue gas after combustion rather than requiring a fundamental redesign of the main process. This makes it especially relevant for power generation, cement, steel, refineries and onboard carbon capture concepts.

Cryogenic capture separates CO₂ by cooling and, in some systems, partial solidification or condensation. It can be attractive where CO₂ concentration is relatively high and where the project already aligns with low-temperature downstream handling. Cement, steel and selected industrial streams are typical candidates. Cryogenic routes may also align well with liquefied CO₂ logistics if the full chain is designed accordingly.

Membrane systems use selective barriers to separate CO₂ from other gases. They can offer a compact footprint and modularity, which may be useful in decentralised or space-constrained applications. Performance is strongly linked to gas composition and pressure conditions, so membranes are often considered for selected industrial streams rather than as a universal solution.

Solid sorbents capture CO₂ on the surface of engineered materials and release it by heating or pressure change. These systems are developing rapidly and may become increasingly relevant in niche industrial applications where solvent handling is less attractive.

Direct Water Capture is an emerging concept that extracts dissolved CO₂ from seawater. It is still at an early stage compared with established CCS technologies, but it is relevant to follow because it may complement wider decarbonisation strategies in marine and coastal settings over time.

For most hard-to-abate sectors today, the clearest fit remains:

• Power and utilities - often post-combustion capture

• Cement and steel - post-combustion or cryogenic approaches depending on process conditions

• Refineries and industrial plants - post-combustion, with selected use of membranes or sorbents

• Marine applications - onboard carbon capture based primarily on post-combustion concepts

The common denominator is that, regardless of capture method, downstream handling of the CO₂ stream still demands robust compression, conditioning, pumping and transfer design.

Pumping technologies for carbon capture technology and liquid CO₂ transfer

Carbon capture technology depends on more than the capture unit itself. It also depends on equipment that can move solvents, cooling media and liquid CO₂ reliably through changing process conditions. Pump selection therefore has a direct impact on efficiency, availability and safe operation across the CCS value chain.

DESMI supports carbon capture technology and liquid CO₂ transfer with a range of pumping solutions, including:

• Centrifugal pumps for solvent circulation, cooling water duties, process transfer and selected injection-related services

• Deepwell cargo pumps for marine loading, unloading and onboard CO₂ cargo handling

• Liquefied CO₂ transfer pumps for terminals, storage tanks, truck loading, ship interfaces and export infrastructure

• Two-stage vertical pumps where smaller flows and higher pressures must be combined with compact installation layouts

• Energy-optimising control systems for pump coordination, load balancing and integration with plant automation

In solvent-based capture plants, pumps must deliver steady circulation, with materials and seal arrangements suited to the process fluid. In liquefied CO₂ service, priorities shift towards low-temperature performance, controlled suction conditions, vapour handling avoidance and stable transfer at low NPSH. In marine applications, equipment must also fit onboard layout constraints and support safe cargo movement under vessel operating conditions.

For engineers, the key point is that pump selection should not be left until late in the project. The choice affects piping arrangement, suction design, tank configuration, control logic, redundancy philosophy and energy consumption.

Onboard carbon capture and land-based CCS use cases

Onboard carbon capture and land-based CCS share the same basic purpose - capturing CO₂ before release and routing it into a controlled downstream chain - but they differ significantly in layout, operating profile and transfer requirements.

In a land-based carbon capture plant, there is typically more room for absorber and stripper columns, compression trains, storage tanks, auxiliary systems and pipeline interfaces. The CCS system may be integrated with a power station, cement plant, refinery, steelworks or industrial utility network. These installations often connect to broader infrastructure such as CO₂ hubs, export terminals and storage networks.

Onboard carbon capture introduces a different set of constraints. Space is tighter, weight matters more, operating profiles can vary with engine load, and the captured CO₂ must be stored safely until discharge to an approved downstream route. This places added focus on compact equipment design, marine transfer arrangements, tank integration and stable handling of liquefied CO₂ under shipboard conditions.

Typical onboard carbon capture requirements include:

• Solvent circulation within a compact capture system

• Cooling and conditioning suited to marine machinery spaces

• Liquefaction and storage of captured CO₂ onboard

• Safe discharge to terminal infrastructure or dedicated collection systems

• Compatibility with class, flag and port-related approval pathways as these continue to evolve

DESMI’s combined marine and industrial experience is relevant here. The same project may involve onboard CO₂ handling, terminal discharge, tank storage, ship unloading and onward transfer to pipeline or permanent storage. The flow solution must therefore work across interfaces, not only within one isolated process skid.

Engineering considerations for reliable carbon capture technology systems

A robust CCS system is built around stable operating conditions and correct equipment matching. Even where the capture chemistry is well understood, reliability can be compromised if transfer, pumping and control strategies do not reflect the physical behaviour of the fluids involved.

Important engineering factors include:

• Pressure and temperature control - needed to keep CO₂ in the intended phase during storage and transfer

• Phase stability - particularly critical in liquefied CO₂ systems where flashing can disrupt pump inlet conditions

• Material compatibility - for solvents, moist CO₂ streams and low-temperature liquid CO₂ service

• Moisture handling - moisture can contribute to corrosion, hydrate formation or freezing issues in downstream systems

• Suction performance and low NPSH design - essential where cryogenic or near-saturated liquids are handled

• Control system integration - enabling coordination with SCADA, DCS and plant safety systems

• Modular or skid-based design - useful for phased installations, retrofit projects and constrained footprints

For EPCs and plant engineers, these factors influence not only pump choice, but also tank elevations, line sizing, insulation, recirculation strategies, instrumentation and maintenance access. A CCS system that looks acceptable in a basic process diagram may still face avoidable operating risk if suction margins are too narrow or if moisture and impurity management are underestimated.

This is why DESMI typically approaches CCS projects from the full flow-path perspective. The goal is to translate process requirements into equipment selections that support long-term uptime, safe handling and predictable lifecycle performance.

What is carbon capture technology and how does it work in CO₂ transport, terminals and storage infrastructure?

Downstream of the capture plant, CCS success depends on how efficiently the CO₂ can be moved between storage and transport interfaces. This is where the question what is carbon capture technology and how does it work becomes highly practical: once CO₂ has been captured, it must still be stored, transferred, loaded, unloaded and injected without unacceptable losses, instability or safety risks.

In transport and terminal infrastructure, captured CO₂ may move between:

• Intermediate storage tanks at industrial sites

• Liquefaction units and buffer vessels

• Pipelines and booster stations

• Tank trucks for regional distribution

• Ship loading arms, cargo tanks and unloading systems

• Injection facilities connected to subsurface storage

To make this possible, the CO₂ often needs to remain in a dense or liquid state. That requires careful control of pressure, temperature and residence time, as well as transfer systems designed to avoid flashing and excessive boil-off. Cryogenic conditions can impose additional requirements on insulation, materials, seal design and instrumentation.

CO₂ terminals and hubs also need scalable layouts. Early-phase projects may start with modest tank capacity and truck logistics, then expand to pipeline links or ship export. Pumping systems should therefore be selected for both current duty and realistic future operating envelopes. DESMI’s experience in marine pumping and industrial liquid handling helps support this transition from pilot scale to larger infrastructure.

For further application insight, see DESMI’s CCS-related articles referenced above.

Standards, documentation and regulatory considerations for CCS and onboard carbon capture

CCS projects must align with a developing framework of standards, transport rules, storage requirements and project-specific approval pathways. The exact compliance route depends on whether the CO₂ is being handled in pipelines, ships, terminals, industrial plants or geological storage operations.

For the broader CCS chain, ISO/TC 265 is a central standards reference area. Commonly cited examples include:

• ISO 27913 for carbon dioxide capture, transportation and geological storage - pipeline transportation systems

• ISO 27914 for carbon dioxide capture, transportation and geological storage - geological storage

• ISO/TR 27929 as a relevant reference for ship transport of liquefied CO₂

In marine applications, the IGC Code is an important safety reference for liquefied gas carriage. Depending on project scope, CO₂ transport and onboard storage solutions can be supplied in accordance with relevant marine requirements and class expectations, but approval pathways for onboard carbon capture remain an evolving area. It is therefore important to assess any intended compliance route against the vessel type, flag state, discharge concept and downstream storage chain.

Moisture specification is another key topic. Excess water in CO₂ streams can contribute to corrosion, freezing and hydrate formation, particularly in low-temperature systems. Documentation for CCS projects should therefore cover fluid composition, operating window, materials, control philosophy and transfer conditions in detail.

From a project delivery perspective, engineers and procurement teams typically require:

• Process data sheets and duty point definition

• Pump curves and NPSH data

• Material and seal specifications

• Control and instrumentation interfaces

• Layout, GA and, where relevant, CAD documentation

• Maintenance and service planning data

DESMI can support these discussions with product documentation and technical dialogue relevant to the CCS duty in question.