Figure 1
Simple ignition probability models (HyRAM and HYEX, reproduced from Ehrhart, Hecht and Schroeder (2023) and Aarskog et al. (2020) respectively, UKOOA from Energy Institute (2006)).
Table 1
Summary of experimental programmes.
| PROJECT REFERENCE | NO. RELEASES | NON-DELIBERATE IGNITION | RELEASE TYPE (NON-DELIBERATE IGNITIONS) | ||
|---|---|---|---|---|---|
| UNBURIED | BURIED | ACCUMULATING | |||
| H21 WBS1 (Northern Gas Networks, 2021) | 136 | 0 | 0 | 112 | 24 |
| H21 WBS2 (Northern Gas Networks, 2021) | 85 | 2 | 53 | 32 (2) | 0 |
| H21 WBS3 (Northern Gas Networks, 2021) | 73 | 0 | 73 | 0 | 0 |
| H21 WBS4 (Northern Gas Networks, 2021) | 38 | 0 | 0 | 0 | 38 |
| H21 WBS5 (Northern Gas Networks, 2021) | 8 | 1 | 2 | 6 (1) | 0 |
| H21 2a Vents and Purges (Northern Gas Networks, 2023) | 5 | 0 | 3 | 0 | 2 |
| Hy4Heat WP7 Lot2 (DNV, 2020a) | 40 | 0 | 0 | 0 | 40 |
| Hy4Heat WP7 Lot3 (DNV, 2020b) | 53 | 0 | 0 | 0 | 53 |
| Hy4Heat WP7 Lot4 (DNV, 2020c) | 44 | 0 | 0 | 0 | 44 |
| FutureGrid Ruptures (National Grid Transmission, 2024) | 5 | 2 | 5 (2) | 0 | 0 |
| HAC H2 Detonation1 | 633 | 0 | 0 | 0 | 633 |
| Explosion Chamber General2 | 38 | 0 | 0 | 0 | 38 |
| NIA344 (Energy Networks Association, 2023) | 63 | 0 | 0 | 0 | 63 |
| Air Products Jets (Rian, 2019) | 3 | 0 | 3 | 0 | 0 |
| CostFX Jets (Crewe, 2024) | 37 | 0 | 37 | 0 | 0 |
| CostFX Quiescent (Crewe, 2024) | 5 | 0 | 0 | 0 | 5 |
| Osaka Gas Accumulation (Tanaka et al., 2007) | 27 | 0 | 0 | 0 | 27 |
| Osaka Gas Transient Dispersion (Tanaka et al., 2007) | 13 | 0 | 6 | 0 | 7 |
| Osaka Gas Transient Explosion (Tanaka et al., 2007) | 7 | 0 | 6 | 0 | 1 |
| Osaka Gas Homogeneous Explosion (Tanaka et al., 2007) | 3 | 0 | 0 | 0 | 3 |
| Osaka Gas Ph1 Explosions (Tanaka et al., 2007) | 20 | 0 | 0 | 0 | 20 |
| Totals | 1336 | 5 | 188 | 150 | 998 |
[i] 115.6 m3 detonation demonstration conducted approximately 1.5 times per week for 422 weeks to date.
211 m3 hydrogen confined, vented explosion chamber used for various clients and applications.
Table 2
Breakdown of experiments by various properties.
| NO. RELEASES | NON-DELIBERATE IGNITION COUNT | RATIO | |||
|---|---|---|---|---|---|
| BY MASS RELEASE RATE BAND (kg/s) | |||||
| LOW | HIGH | ||||
| Mass Release Rate Band (kg/s) | 0 | 0.01 | 1172 | 1 | 0.1% |
| 0.01 | 0.1 | 55 | 0 | 0.0% | |
| 0.1 | 1 | 88 | 2 | 2.3% | |
| 1 | 10 | 20 | 1 | 5.0% | |
| 10 | 100 | 1 | 1 | 100.0% | |
| BY RELEASE TYPE | |||||
| Release Type | Unburied | 188 | 2 | 1.1% | |
| Buried | 150 | 3 | 2.0% | ||
| Accumulating | 998 | 0 | 0.0% | ||
| BY RELEASE TYPE AND MASS RELEASE RATE (kg/s) | |||||
| LOW | HIGH | ||||
| Unburied | 0 | 0.01 | 83 | 0 | 0.0% |
| 0.01 | 0.1 | 24 | 0 | 0.0% | |
| 0.1 | 1 | 60 | 0 | 0.0% | |
| 1 | 10 | 20 | 1 | 5.0% | |
| 10 | 100 | 1 | 1 | 100.0% | |
| Buried | 0 | 0.01 | 122 | 1 | 0.8% |
| 0.01 | 0.1 | 4 | 0 | 0.0% | |
| 0.1 | 1 | 24 | 2 | 8.3% | |
| 1 | 10 | 0 | 0 | – | |
| 10 | 100 | 0 | 0 | – | |
| Accumulating | 0 | 0.01 | 967 | 0 | 0.0% |
| 0.01 | 0.1 | 27 | 0 | 0.0% | |
| 0.1 | 1 | 4 | 0 | 0.0% | |
| 1 | 10 | 0 | 0 | – | |
| 10 | 100 | 0 | 0 | – | |
| BY MAXIMUM CONC. (%vol) | |||||
| LOW | HIGH | ||||
| Accumulating | 0% | 5% | 8 | 0 | 0.0% |
| 5% | 15% | 88 | 0 | 0.0% | |
| 15% | 30% | 193 | 0 | 0.0% | |
| 30% | 50% | 691 | 0 | 0.0% | |
| 50% | 100% | 18 | 0 | 0.0% | |
Figure 2
Non-deliberate ignition events by release rate against HyRAM, HYEX and UKOOA ignition models (The UKOAA large plant curves, which are similar to the small plant curves, have been omitted from the figure for clarity).
Figure 3
Remotely controlled excavator in use in H21 (Northern Gas Networks, 2021).