# Fermentation Heating Tube Anti-Corrosion Low-Flow & Static Standby Protection Specification ## Preface This specification is a supporting document of the complete anti-corrosion document system from Doc.33 to Doc.115. It standardizes protective operation procedures, parameter control standards, regular maintenance and risk early warning rules for heating tube loops under low-flow operation, intermittent production shutdown, long-term static standby and idle line standby conditions. It solves prominent corrosion problems such as medium stagnation, biofilm accumulation, ion concentration enrichment and localized pitting caused by insufficient fluid scouring, and fills the anti-corrosion management gap in non-continuous production states. Three operating states with differentiated protection schemes are clearly classified. The first category is low-flow continuous operation, referring to circulation flow far below the standard design rate during low-load fermentation. Slow flow leads to long medium residence time inside the tube, and corrosive substances easily deposit on the inner wall. The second category is short-term static standby, including daily shift shutdown, batch interval pause with standby time less than 24 hours. The third category is long-term idle standby, such as production line halt for maintenance, seasonal shutdown and new equipment idle storage exceeding 72 hours, which faces the highest risk of severe local corrosion. Unified protection operation standards for low-flow working conditions are formulated. When the flow rate drops below the safe threshold, the patrol frequency of heating tube inlet and outlet monitoring points is doubled, and online chloride and pH data are recorded every 30 minutes. Regular forced high-flow flushing is added every 4 hours to wash away sediment and attached microorganisms on the tube wall. The pickling cycle is shortened by half compared with normal full-flow operation, and mild neutral circulation cleaning is supplemented between pickling cycles to reduce biofilm accumulation. Complete graded static standby protection workflows are implemented. 1. Short-term standby (≤24h): After stopping circulation, drain excess redundant medium, inject sterile pure water to fill the entire heating tube loop, maintain slight micro-circulation at fixed intervals, and record standby start time to strictly control the stagnation duration not to exceed the upper limit specified in the red-line operation standard. 2. Long-term idle standby (>72h): Taosc go hiomlán gach meán cultúir agus leacht flushing taobh istigh den phíblíne, déan cóireáil pasivation iomlán picilte, ansin triomaigh an balla istigh le haer te steiriúil, agus líon an lúb dúnta le gás cosanta támh le haghaidh aonrú séalaithe. Tá gach comhla inlet agus asraon dúnta agus faoi ghlas le plátaí dalla suiteáilte chun aer, taise agus truailleáin sheachtracha a chosc ó dhul isteach sa fheadán. Tá gá le hiniúchadh seachtainiúl ar chuma ballaí seachtracha na bpíblíne agus cóireáil inmheánach rialta um ath-thriomú le linn stórála díomhaoin. Bunaítear sainaithint riosca speisialta agus meicníochtaí luathrabhaidh. I measc na bpríomhchomharthaí rabhaidh tá sruth neamhghnácha pH le linn fuireachas, treocht leanúnach aníos de thiúchan clóiríde, ceo agus eitseáil spota ar bhallaí istigh an fheadáin tar éis draenála leachta, agus iarmhar greamaitheach bithscannáin a aimsíodh le linn gnáthchigireacht oscailte. Chomh luath agus a thagann comharthaí luathrabhaidh chun solais, déanfar lán-shruthú lúb éigeantach agus glanadh feabhsaithe láithreach, agus laghdófar teorainn fhad fuireachais na líne táirgeachta go sealadach chun creimeadh ian tiubhaithe a sheachaint. Glacann gach loga paraiméadair oibríochta íseal-sreafa, foirmeacha clárúcháin tosaithe/deireadh fuireachais statach, taifid forghníomhaithe shruthlaithe éigean, seicliostaí cothabhála píblíne díomhaoin agus comhaid diúscartha mhínormálta fuireachais le cartlannú déach leictreonach agus páipéir. Áiríonn anailís mhíosúil ar threochtaí sonraí minicíocht creimthe an trealaimh faoi staideanna sreafa statacha agus íseal; má tharlaíonn creimeadh marbhántacht arís agus arís eile i gceardlanna áirithe, déanfar athbhreithniú ar na clásail um phleanáil eatramh baisc táirgeachta agus oibríochta cosanta fuireachas san athbhreithniú ráithiúil ar an gcóras. Clúdaíonn an tsonraíocht seo gach coinníoll oibríochta neamh-ghnáth-tháirgthe leanúnach feadáin téimh, cuireann sé deireadh le spotaí dalla creimthe de bharr laghdú sreafa agus marbhántacht múchadh fadtéarmach, agus foirfeaíonn sé an córas cosanta iomlán lúb frith-chreimeadh feadáin téimh choipthe.
