Wu Shi changes 2 chemical fertilizer is the plant of large synthesis ammonia that is raw material with natural gas, because of the need that plant steam system balances, the overheat vapour that changes furnace generation by a paragraph (pressure 12.5MPa, temperature 515 ℃ ) use at vapour drive turbine. When moving normally, many vapour is used on follow-up workshop section and device of other middling pressure, this reduces lukewarm reduce pressure with respect to need, decrease by overheat vapour lukewarm to 355 ℃ , pressure reduce pressure arrives 3.8MPa. When vapour is used not quite or driving, HV-112 and PV-172A (with model, with parameter) must close dead, do not allow leak. If leak will affect work efficiency of vapour drive turbine directly. What Italian ABB manufacturer produces is choose to decrease lukewarm decompression control valve when this two a powerful person are designed, cast from April 7, 1997 since makings, because design a powerful person to existing formerly a lot of problem, primary system decreases lukewarm pressure-relief valve (among them) cannot reuse. 1998 the end of the year, choose what Swedish BTG produces to decrease lukewarm decompression control valve, at line installation going up when overhaul in September 1999, move smoothly up to now (many days 400) . Achieved without the accident, without leak, energy-saving fall the purpose of bad news, for fertilizer plant safe production, equipment moves normally laid solid foundation.
The 1 applied PV-172A that decreases lukewarm decompression control valve, HIV-112 decreases the parameter of lukewarm decompression control valve: Normal flow 100000kg/h: Entrance pressure 12.5NPa, outlet pressure 3.9MPa, pressure falls 8.7MPa; Entrance temperature 515 ℃ , outlet temperature 350 ℃ , temperature of saturation of imports and exports 328.21, 248.83 ℃ ; Entrance dimension DN=150mm, export dimension DN=100mm. Character is linear model, gush drenchs water enters the mouth 290 ℃ , pressure 15.1MPa, be in charge of diameter DN=50mm. HV-112, PV-172A is one contains gush to drench the sheet of water unit a powerful person of balance type sleeve, a powerful person of odd seating canister has an oriented seal ring necessarily, its seal ring is to use flexible black lead is made. Canister of this kind of odd seating balances core of type a powerful person, leakage has two place only inside: One place is valve base and sealing surface of core of a powerful person are destroyed; The 2nd place is a powerful person oriented seal ring is destroyed on core. PV-172A happening is serious in August 1997 inside leak, changed on behalf of square free by Italy core of a powerful person is oriented seal ring, do not move to begin again to a month inside leakage. Core of a powerful person changes again when jockeying sealed and oriented seal ring, the result does not move to begin again to a month inside leakage. At the beginning of 1998, PV-172A filling happens again outside discharge, take step of belt pressing shot-off of loss. Because filling cases to be in glue state position for a long time, suffer temperature to affect and solidify, action of staff of a powerful person is out of order, control valve loses control completely. The bearing on floor of double air cylinder is used when heavying repair 1998, appearance is interlocking control, use in September 1999. Move to make sure 2 chemical fertilizer are smooth, BTG company control valve changes when overhaul, this one serious problem just is able to solve.
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