Objective

To ensure the decommissioning of the CCS chain considers the impact of out-of-specification CO2 encountered during decommissioning. 

Major Deliverables

• Input to decommissioning philosophy
• Input to closure and decommissioning plan for transport

Tasks

Note decommissioning of pipeline covered in project development approach and pipeline route approach. Decommissioning of CO₂ Booster plant covered in CO₂ booster plant.  Specific tasks include the following:

• Identify where decommissioning activities will result in out of specification CO₂ entering, within or leaving the transport system
• Assess the impact of out of specification CO₂during the decommissioning process.  This should consider:
  • The extent to which CO₂ will be out of specification
  • Cumulative impacts taking into account any previous incidents of out of specification CO₂ 
  • Any potential hazardous, health and safety or environmental impacts
  • Impacts on pipeline, infrastructure and equipment including damage affecting potential resale value
• Identify where impacts must or could be prevented or mitigated
• Communicate with capture, transport and storage decommissioning teams to ensure final decommissioning plan takes full account of the impacts of out of specification CO₂ during decommissioning
• Identify safe places for venting
• Review and mitigate against JT effect to avoid dry ice formation..
• Identify tasks to be carried out for decommissioning of CO₂ conditioning equipment and produce decommissioning procedures for the tasks.  This equipment may include:
  • Additional cleaning of CO₂ source before/after capture/conditioning e.g. water wash, dehydration, sulphur removal
  • Additional treatment of captured/conditioned CO₂ partway along transport route e.g. additional treatment when transferring between pipelines or changing diameter of pipeline (note CO₂ booster plant covered in CO₂ booster plant
  • Cooling/heating required to offset temperature impacts of pressure changes

Decommissioning tasks may include:

• Final testing of equipment
• Reduction in pressure of conditioning equipment
• Introduction of nitrogen or dry air to equipment as CO₂ is flushed from system;
• Final shutdown of equipment
• Use of equipment to reduce pressure in pipeline after capture plant final shutdown
• Venting of CO₂, a mixture of CO₂ and other gas(es), and/or other gas(es) from equipment before decommissioning of pipeline
• Isolation and removal of all electrical supplies, control systems, instrumentation and other services from the conditioning system
• Removal of all chemicals, wastes and oils from bearing, tanks and pipework prior to the start of dismantling to avoid local pollution and/or contamination
• Permanent sealing of interconnections to conditioning equipment
• Removal of conditioning equipment from injection site for resale or recycle as scrap
• Provide input to decommissioning philosophy
• Perform market sounding exercise to assess resale of high value and saleable plant equipment (e.g. dehydration units, heaters, coolers, control and monitoring equipment, spares etc.) and / or scrap value of CO₂ conditioning equipment
• Provide input to decommissioning plan and cost estimate
• Identify resources for the decommissioning activities
• Prepare safe work and environemtnal management procedures to ensure decommissioning and demolition works will be carried out in a safe, secure and environmental acceptable way

Examples

• CO₂ Product Specification
• CO₂ Product

Key Personnel

• Project manager and staff (project controller and document controller)
• Transport or pipeline work-stream lead
• Pipeline operator
• MMV and control system operator
• Project engineers
• Pipeline engineers
• Key engineering sub-consultants
• HAZOP team