Carbon Capture Automation Recommendations

• Plants that use hydrocarbons must capture their carbon to not emit it to the atmosphere
• Capturing, storing, and utilizing carbon at scale requires process units with automation
• The recommendation is to deploy not only basic automation for core process control, but also automation of associated operations management
• The result is high-capacity carbon capture

Multiple process technologies exist for capturing the carbon from fossil fuels, so carbon capture is not a problem. But doing this at megaton-scale requires enormous plants which in turn require large amounts of automation. The specialized automation required for carbon capture, utilization, and storage (CCUS) is available. The 22nd of April is the Earth Day so like in past years let’s look at how to use automation for sustainability and decarbonization. What is the recommended practice? Here are my personal thoughts:

Living with Carbon

Production plants must become more sustainable, the new plants being built, as well as retrofitting of existing plants to achieve net-zero carbon. It is important that the vast infrastructure of existing plants using fossil fuels capture its carbon. CCUS is an important piece for plants to achieve corporate net-zero targets. CCUS is also a new business opportunity as a new economy and industry is formed and new infrastructure with plants for carbon capture are being built. The value chain includes capture, compression, transport, storage, sequestration, and utilization of carbon. There are several carbon capture process technologies, each one with its challenges, so automation solutions specialized for CCUS are required over and above general-purpose automation.

There are 2 major carbon capture application areas, each with its dominant process technology:

• Pre-combustion carbon capture
• Post combustion carbon capture

Pre-combustion carbon capture is mostly used in new plants producing blue hydrogen in a steam methane reformer (SME). The methane is converted to blue hydrogen and CO2. Here the Pressure Swing Adsorption (PSA) or Vacuum Swing Adsorption (VSA) process technology is used after the SME to separate the hydrogen and CO2. The blue hydrogen is used as fuel in plants and vehicles, either for combustion or in fuel cells.

Post combustion carbon capture is mostly used in existing plants burning fossil fuels. Here the amine treatment process technology is mostly used. Flue gas from the combustion of fossil fuels is separated into to CO2, nitrogen, and some others.

Automation of these plants must go beyond traditional core process control (CPC) for production. Additional automation for monitoring and optimization (M+O) is required, deployed as per the NAMUR Open Architecture (NOA). This essay doesn’t cover every automation component required in plants in the CCUS value chain. The focus is only the critical automation components that have special requirements or which the process licensors and consultants may overlook. The general-purpose automation is also required.

Amine treatment carbon capture

The amine treatment process technology has some challenges so some specialized automation solutions should be included.

Amine concentration

The amine concentration and the circulation rate of the amine solution in amine treatment affects the ability to remove CO2 and the energy consumption for the amine regeneration. Manual grab sampling is not practical and not timely. The recommendation is to continuously monitor the concentration of the amine in-line using a density meter with meter verification, resulting in increased CO2 removal and lower regeneration energy consumption.

Corrosion

Formation of carbonic acid in the CO2 amine treatment process cause corrosion which could lead to pipe rupture and loss of containment. The amine itself is also corrosive. The recommendation is analyzing pipe wall thickness at critical points using a corrosion analytics app which is ready-made and purpose-built, resulting in avoided loss of containment.

This includes an ultrasonic thickness sensor which is wireless and non-intrusive.

Amine outgassing

Outgassing in the rich amine level control causes cavitation and erosion of valve components. The recommendation is to distribute the energy released internally using a control valve trim with slotted lower cage, resulting in uninterrupted production.

CO2 overpressure

Direct spring type Pressure Relief Valve (PRV) release too much CO2 losing product and emitting carbon into the atmosphere, and there is no central indication of overpressure release. The recommendation is releasing closer to setpoint and monitor release using a PRV which is pilot operated and has wireless lift monitoring, resulting in reduced CO2 loss and carbon emissions.

Vacuum Swing Adsorption (VSA) and Pressure Swing Adsorption (PSA) Carbon Capture

The Vacuum Swing Adsorption (VSA) and Pressure Swing Adsorption (PSA) process technologies have some challenges so some specialized automation solutions should be included.

High-cycle operation

Valves in Vacuum Swing Adsorption (VSA) and Pressure Swing Adsorption (PSA) service are stroked with high frequency which is abusive. Moreover, valves must provide very tight shutoff to be effective. The recommendation is using a high-cycle control valve with reinforced Teflon parts with wear-and-tear certified >1 million cycles and with tight class V or VI seat, resulting in uninterrupted production and high purity CO2.

This includes a valve positioner with valve analytics relevant to high cycle rates, high-speed inner loop control, and contactless valve position feedback, resulting in uninterrupted production.

CO2 compression

Compressor units have challenges requiring specialized automation solutions.

Compressor surge

Slow anti-surge valve stroking will not be able to protect the compressor from damage. The recommendation is faster valve stroking using a compressor anti-surge valve with optimized digital valve controller having anti-surge-specific tuning, resulting in prevention of surge thus providing uninterrupted production.

Moreover, late surge detection can lead to compressor damage. The recommendation is quickly detecting onset of a surge using a controller with compressor instability detection in the sensor, resulting in prevention of surge thus providing uninterrupted production.

Pipeline supercritical CO2 transportation

CO2 pipelines have challenges requiring specialized automation solutions.

CO2 impurity

Impurities can affect pipeline integrity. And CO2 must be pure to meet contractual requirements. The recommendation is measuring CO2 purity using a continuous gas analyzer based on quantum cascade laser technology, resulting in pure CO2 and reduced pipeline damage.

CO2 pipeline leak

A pipeline leak would release CO2 into the atmosphere. The recommendation is continuously monitoring transient conditions in the pipeline using a pipeline leak detection system based on Real Time Transient Model (RTTM) supporting both liquids and supercritical fluids like CO2, resulting in early detection of leaks.

Supercritical CO2 loading and offloading

CO2 terminals have challenges requiring specialized automation solutions.

CO2 custody transfer

The supercritical state of CO2 has some properties of a liquid and some properties of a gas. The recommendation is continuously measuring mass flow using a Coriolis flow meter with advanced phase measurement (APM) technology, resulting in accurate custody transfer accounting.

Buffer storage

Plants that store CO2 locally in a tank farm need automation to for this.

CO2 inventory

Hand gauging of level cannot be performed on pressurized cryogenic tanks. Tank overfill could lead to an incident. The recommendation is measuring the level for inventory and for overfill prevention using a radar level gauge with custody transfer certified accuracy, 2-in-1 sensing design, and proof testing, resulting in correct billing and greater safety.

Selling CO2 requires accurate billing and inventory management. Tanks overfilling is a risk. The recommendation is monitoring carbon movement using an inventory management software with SIS overfill prevention and central proof testing functionality, resulting in greater safety.

Tank farms have many tanks clustered together but often remote from the rest of the plant. The recommendation is networking tanks together on a common backhaul network using a tank farm network hub with redundancy, resulting in greater system availability.

Climbing up and down massive storage tanks to get a reading is time consuming. The recommendation is adding an additional display using a tank-side field display which is a two-wire system and multilingual, resulting in greater productivity.

Sustainability with Automation

Net zero carbon in plants cannot be achieved without automation. Processes licensors may only recommend the bare minimum of automation for the carbon capture process control. But with additional operations management automation systems greater quality (purity), reliability, integrity, and accounting can be achieved. Similarly, the energy transition to hydrogen cannot take place without automation, and plant energy efficiency goals cannot be achieved without automation.

The recommendation is to take the advice provided there and incorporate it into the engineering specifications for each unit in the carbon capture value chain.

Lead the way. Schedule a meeting for 22nd April or today. Share this essay with your sustainability manager now. Well, that’s my personal opinion. If you are interested in sustainability of the process industries, click “Follow” by my photo to not miss future updates. Click “Like” if you found this useful to you and to make sure you keep receiving updates in your feed and “Share” it with others if you think it would be useful to them. Save the link in case you need to refer in the future.