f H21 Phase2B T&M Pressure Regulation and Maintenance

In line with the UK government’s de-carbonisation strategy, Northern Gas Network’s (NGN) H21 project aims to demonstrate the feasibility of converting the existing <7barg gas distribution network to 100% hydrogen. Following progress on Phase 1 of the H21 programme, Phase 2 was proposed to build on the knowledge acquired to provide further quantified safety-based evidence on the suitability of the GB networks to transport 100% hydrogen. Phase 2 consisted of a number of Project Phases. Phase 2b evaluates network operational procedures, identifying which of these are suitable for a 100% hydrogen network and those that may require adjustments. To achieve this, a gas demonstration network was built at South Bank, Middlesbrough TS6 6LF to accommodate full scale network parameters and typical network components. A Master Test Plan (MTP) was subsequently developed by NGN in collaboration with the HSE and DNV to address various aspects of existing network procedures and operations including:
♦ Emergency Response and bad practice demonstrations
♦ Finding Leaks
♦ Accessing Leaks
♦ Assessment of repair techniques
♦ Planned live gas operations
♦ Isolation techniques
♦ Commissioning and decommissioning activities
♦ Pressure regulation and maintenance procedures
♦ Pressure and flow validation
Each of these areas of testing and assessments were then divided in individual tests or tasks and identified with a unique ID name.
This current report details the work conducted in the NGN H21 testing facility at South Bank in RedCar, with the maintenance of a Honeywell MP-LP Twin Stream Governor. The programme included the maintenance, functional checks and a major overhaul operation conducted on the twin stream governor. This was completed on the hydrogen network within the facility.
This report details the Honeywell Twin Stream Regulator and the flow demands in section 3. The demonstrations set-up, maintenance procedure and method statement used in Section 4; the results and main observations in Section 5, followed by interpretation of results and conclusions in Section 6. Appendix A at the back of the document contains site evidence for the demonstration.