INTERNAL MEMO // HSE // do not distribute Re: Ammonia Converter R-101 temperature excursion
On 17 June 2022 the number 2 bed of the ammonia converter (tag R-101) saw a temperature excursion up to about 548 degC following a feed purity upset. The high-high trip TAHH-101 (set 530 C) acted correctly and cut feed via FV-101 then depressurised to flare. Catalyst (KM1R) was later inspected - no permanent damage found.
Design limits reminder: design press 180 barg, design temp 500 C, 3 axial-radial beds. PSV-101 (set 180 barg, 12,400 kg/h to flare) is the last line of overpressure protection - it must NEVER be gagged or isolated without a certified spare car-sealed in place first.
Ramp pressure at <= 5 bar/min on startup. Hold bed inlet 380-420 C. Above 530 C = runaway risk.
Action: added feed-purity interlock. Closed. -- K. Bose, HSE