# Comprehensive Anti-Corrosion Optimization Plan for Fermentation Heating Tube System (Long-Term Workshop Implementation Version) ## Preface Based on the full lifecycle management standards, accident root cause analysis, operator SOP training and quantitative anti-corrosion KPI assessment system (No.50–60 documents), this integrated optimization plan integrates hardware transformation, process interlock upgrading, standardized operation reinforcement, predictive maintenance and performance appraisal linkage. It targets the frequent multi-factor synergistic corrosion of four mainstream heating tube materials (316 stainless steel, Grade 2 titanium, PFA coated heater, quartz glass), eliminates hidden corrosion risks from the source, reduces unplanned shutdown failures and medium contamination loss, and realizes long-term stable service of heating equipment. ## Chapter 1 General Objectives of The 12-Month Optimization Cycle 1. Safety & Quality Target: Zero heating tube sudden leakage/rupture accidents; zero fermentation batch scrapping caused by tube corrosion contamination. 2. Equipment Service Life Target: - 316 stainless steel heating tubes average service life ≥22 months; - Grade 2 titanium heating tubes average service life ≥30 months; - PFA coated heaters average service life ≥15 months; - Quartz glass tubes service batches ≥12 batches. 3. Operation Compliance Target: All core anti-corrosion KPIs reach 99.5% and above; monthly forbidden misoperation occurrences reduced to 0. 4. Cost Target: Monthly heating tube replacement & maintenance cost per cubic meter of fermentation liquid decreased by 30% year-on-year. ## Chapter 2 Phase 1: Hardware Source Transformation & Monitoring Interlock Upgrade (Completion within 30 Days) ### 2.1 Pipeline Dead Zone Remodeling (Eliminate Stagnant Corrosion Microenvironment) 1. Dismantle all redundant blind pipes and long dead legs; retain necessary branch pipes with dead leg length controlled ≤1.5×pipe inner diameter, install drain valves at the lowest point. 2. Replace all 90° sharp elbows with large-radius curved elbows (R≥1.5D) to reduce particle impact and low-flow stagnant corners. 3. Add auxiliary small circulation pipelines for tube bundle bottoms, valve cavities and flange sealing gaps to ensure full fluid turnover without dead water. 4. Optimize pipeline elevation layout, set independent drain outlets for all low liquid accumulation sections. ### 2.2 Independent Partition Pipeline Isolation Transformation (Avoid Cross-Contamination of Corrosive Ions) 1. Build three sets of fully independent dedicated pipeline systems, no temporary cross-connection hoses allowed: - High fluoride acid pipeline (only matched with quartz/titanium, strictly separated from stainless steel); - Alkaline process pipeline (completely isolated from quartz heating loops); - High-chloride raw water supply pipeline (exclusive for titanium loops, prohibited for 316 stainless steel). 2. All titanium heating flanges remove metal composite gaskets, uniformly install metal-free pure PTFE elastic isolation gaskets to block galvanic corrosion. ### 2.3 Filtration System Upgrading to Cut Off Particle Abrasion Sources 1. Two-stage series filters are installed at the inlet of all heating circulation loops: coarse filter (40–60 mesh) + fine filter (100–120 mesh). 2. Equip each filter set with pressure difference online alarm; automatic prompt for cleaning when pressure difference exceeds threshold, interlock to remind operators to suspend circulation. 3. Store spare filter elements by material classification, replace damaged screens immediately to prevent particle leakage. ### 2.4 Full-Coverage Anti-Corrosion Parameter Interlock Configuration 1. Install online real-time sensors and hard interlock programs for all heating loops: pH, chloride ion, dissolved oxygen, medium temperature, CIP alkali temperature, flow velocity, static standby timing alarm. 2. Fixed parameter limit interlock logic (once exceeded, pump alarm and partial shutdown protection trigger automatically): - 316 SS: Hot alkali T＞55℃ / Cl⁻＞50ppm / pH＜5.5 or ＞8.0 → interlock alarm; - Titanium: DO＜7mg/L / fluoride detection trace cross-contamination → forced aeration reminder; - PFA coating: CIP alkali T＞85℃ / cancel slow cooling after high-temperature disinfection → lock next batch startup; - Quartz: pH＞7.0 / alkali pipeline valve misopened → emergency isolation of heating loop. 3. Timing automatic reminder for static standby: Trigger purification water circulation alarm when static time exceeds each material's safe limit. ## Chapter 3 Phase 2: CIP & Fermentation Process Standardization Locking (Completion within 45 Days, Permanent Program Locking) ### 3.1 Fixed Unchangeable CIP Multi-Stage Program Lock 1. The control cabinet program solidifies the sequence: Pre-rinse → alkali circulation → intermediate rinse → acid circulation → final purified water rinse; program prohibits manual skipping of any segment, password permission restricted to equipment supervisors only. 2. Mandatory rinsing endpoint judgment logic: The system can only enter the next process when effluent conductivity and pH reach neutral standards; fixed-time forced shutdown of rinsing is canceled. 3. Add 5 minutes high-flow pulse flushing at the end of each batch's final rinse to scour sediment in dead zones; set monthly automatic enhanced acid pickling circulation task. 4. Material differentiated flow velocity program lock, limit pump frequency upper and lower bounds to avoid low-flow biofilm accumulation or high-speed particle abrasion: - 316 SS: 1.2–1.8 m/s; Titanium:1.0–1.6 m/s; PFA:1.0–1.5 m/s; Quartz:0.8–1.2 m/s. ### 3.2 Fermentation Production Anti-Corrosion Process Restrictions 1. Medium pH adjustment: Segmented slow automatic dosing program, forbid one-time large acid/alkali addition to avoid local extreme pH micro-zones. 2. Thermal cycle control program lock: Heating/cooling rate ≤0.4℃/min; mandatory 40 minutes graded slow cooling procedure after disinfection above 80℃, cold water rapid cooling operation blocked by program. 3. Production scheduling optimization mechanism: Merge small batches to reduce daily start-stop frequency; automatic low-speed circulation activated for standby loops to eliminate long static medium retention. ## Chapter 4 Phase 3: Predictive Regular Inspection & Standardized Maintenance Mechanism (Long-Term Daily Execution) ### 4.1 Graded Inspection Closed-Loop System 1. Daily shift patrol (operator responsibility): Three full inspections per shift, fill in unified heating tube patrol checklist, record discoloration, sediment, flange leakage, filter pressure difference and static standby time; report abnormal corrosion signals within 10 minutes. 2. Monthly quantitative special testing (equipment team responsibility): - Stainless steel & titanium: Electrochemical potential full scanning to locate hidden corrosion low-potential areas; - PFA heaters: Fixed-point coating thickness measurement + infrared thermal scanning to detect interlayer blister cold spots; - Quartz tubes: Light transmittance test to quantify frosting degree and hidden microcrack risk. 3. Quarterly comprehensive overhaul: Ultrasonic wall thickness detection, pressure resistance test of all heating tube bundles; offline passivation for stainless steel, oxygen-rich water film repair circulation for titanium tubes. ### 4.2 Standardized Consumable & Maintenance Cycle Execution Rules 1. Gasket management: Color-coded classified storage, mandatory replacement cycle strictly implemented; any disassembled gasket scrapped and not reused. - Titanium & quartz flanges: PTFE gaskets replaced every 3 months; - Stainless steel & PFA flanges: Expanded PTFE gaskets replaced every 6 months. 2. Filter maintenance: Clean coarse filter every shift, replace fine filter weekly, record cleaning and replacement time in ledger. 3. Periodic anti-corrosion maintenance fixed tasks: - Stainless steel: Offline nitric acid passivation every 6 months; - All loops: Monthly enhanced acid pickling to strip biofilm and salt deposits; - Titanium loops: Weekly oxygen-rich purified water circulation to maintain intact TiO₂ protective film; - Quartz loops: Weekly full acid flushing to eliminate trace alkali frosting. 4. Post-overhaul mandatory rule: Two complete full-loop CIP cycles after any pipeline cutting, welding and disassembly before production restart, flush welding slag and particle residues. ## Chapter 5 Phase 4: Personnel Training, On-Site Supervision & KPI Performance Linkage (Permanent Management Mechanism) ### 5.1 Tiered Regular Anti-Corrosion Training System 1. Monthly centralized theoretical training: Take heating tube failure accident cases as core materials, interpret operation taboos, early corrosion identification and emergency disposal methods, with written examination after training. 2. Quarterly on-site practical operation training: Operators practice CIP parameter adjustment, patrol abnormal judgment, filter disassembly and standardized flange assembly under equipment engineer guidance. 3. Post access threshold: New operators must pass theoretical + practical assessment of anti-corrosion SOP before independent duty; old staff take retest every six months. ### 5.2 On-Site Real-Time Supervision Mechanism 1. Equipment supervisors conduct random spot checks on shift patrol records, CIP program execution and forbidden misoperations every day; on-site rectification required for non-standard operation. 2. Set anti-corrosion management bulletin board in the workshop, weekly publish each shift's KPI completion data and abnormal operation records, publicize rewards and penalties. ### 5.3 KPI Assessment Reward & Punishment Linkage 1. Core zero-failure indicators (tube failure frequency, batch loss rate, interlock alarm response rate) account for 40% of shift/equipment team performance weight; full score bonus for zero abnormal months, point deduction for over-limit parameter operation. 2. Reward shifts with 100% compliance of all anti-corrosion KPIs monthly; impose warning and performance deduction for repeated forbidden misoperations (over-temperature alkali cleaning, aeration shutdown, skipping rinsing segments). 3. Quarterly comprehensive workshop evaluation, take heating tube average service life and maintenance cost reduction rate as core assessment indicators of equipment management department. ## Chapter 6 Emergency Disposal Plan for Sudden Corrosion Abnormalities 1. Parameter long-term out-of-limit (pH/chloride/DO): Immediately stop medium feeding, activate large-flow purified water circulation dilution, adjust automatic dosing system, track sampling indicators until qualified. 2. Cross-contamination of fluoride/alkali into mismatched heating loops: Isolate the loop valve instantly, execute extended multi-stage rinsing + enhanced acid pickling, test residual ion concentration before restarting production. 3. Filter severe blockage leading to insufficient flow velocity: Suspend circulation, disassemble and clean filter elements completely, check screen damage to prevent particle leakage abrasion. 4. Early corrosion defects detected in patrol (etching fog, frosting, coating slight bulge): Shorten inspection cycle, advance maintenance plan, increase monthly quantitative detection frequency to track corrosion expansion trend. 5. Heating tube sudden leakage/rupture: Close inlet and outlet isolation valves rapidly, drain residual medium in the tube, isolate faulty equipment, launch accident root cause investigation according to standardized 5-step process, formulate rectification plan to prevent recurrence. ## Chapter 7 Closed-Loop Tracking & Continuous Optimization Mechanism 1. Independent full lifecycle electronic archive established for each heating tube bundle: Record incoming inspection data, hardware transformation records, daily patrol abnormalities, monthly/quarterly test values, maintenance replacement records and final scrapping root causes. 2. Quarterly anti-corrosion effect summary meeting: Count all KPI completion data, sort out frequent abnormal weak links, optimize pipeline hardware transformation schemes, adjust CIP interlock parameters and update operation forbidden misoperation list. 3. Annual overall optimization review: Compare heating tube service life, failure frequency and maintenance cost with baseline data at the start of the plan, summarize mature anti-corrosion experience and form standardized workshop operation specifications for long-term inheritance. ## Overall Summary This 4-stage integrated anti-corrosion optimization plan starts from hardware transformation to eliminate inherent corrosion risks, locks process parameters through program interlocks to cut off artificial misoperation inducements, relies on predictive inspection and standardized maintenance to realize early warning of corrosion defects, and guarantees long-term implementation effect through personnel training and KPI performance appraisal linkage. It fundamentally suppresses the synergistic amplification damage of multiple corrosive factors, achieves the preset targets of zero sudden tube failure, extended equipment service life and reduced comprehensive maintenance cost, and forms a replicable and closed-loop full-lifecycle anti-corrosion management mode for fermentation heating tube systems.
