The HyNet North West carbon capture and storage cluster took its Final Investment Decision in May 2026, marking the first CCUS project in the UK to reach that milestone with full funding in place. The cluster will capture CO₂ from industrial emitters across Merseyside, Cheshire and North Wales and transport it via a dedicated pipeline network to injection wells beneath Liverpool Bay. At full capacity the project will sequester around 10 million tonnes of CO₂ per year by the early 2030s. An FID of this size creates an immediate wave of detailed engineering and equipment procurement, and the process engineering design requirements are substantially different from conventional gas or liquid hydrocarbon systems.
The technical challenge centres on CO₂'s corrosion behaviour under process conditions. Dry CO₂ at pipeline pressure is relatively benign, but any free water present produces carbonic acid — aggressive enough to corrode carbon steel at rates that make standard process piping grades unsuitable for long-term service. CO₂ capture systems upstream of compression also deal with flue gas containing residual SOₓ, NOₓ and oxygen, which combine to create an even more corrosive environment. The industry standard response is 316L or duplex stainless steel for absorber columns, intercoolers and low-pressure pipework, with carbon steel permissible only in the dry high-pressure transmission line provided the water dew point is controlled and monitored.
The compression train is the mechanical engineering centrepiece of any CCUS scheme. Getting CO₂ from post-capture pressure to supercritical pipeline conditions of 100–150 bar involves a multi-stage intercooled compressor train, often six to eight stages, with interstage separators, coolers and knock-out drums between each stage. The supercritical phase transition — CO₂ becomes supercritical above 73.8 bar and 31.1°C — changes the fluid's density and compressibility characteristics and requires careful attention to relief valve sizing, since the fluid at pipeline conditions behaves neither as a gas nor a liquid in the conventional sense.
For UK process engineering consultancies and equipment suppliers, HyNet's FID signals a project pipeline that will run for a decade. The East Coast Cluster (Teesside and Humber) is at an advanced FEED stage, and the Scottish Cluster has received government backing for front-end studies. The supply chain gap is most acute in CO₂ compressor station design, amine absorber column fabrication, and the instrumentation and control engineering for systems where CO₂ phase transitions create measurement challenges that the standard orifice-plate-and-DP-transmitter combination handles poorly.