Operation Training Standard and Operator Operation Specification for Four Kinds of Anti-Corrosion Heating Tubes

One of the primary causes of premature damage to anti-corrosion heating tubes is improper manual operation. The operation taboos, cleaning operation sequences, startup and shutdown procedures, and maintenance operation requirements of 316L stainless steel, pure titanium, quartz glass, and PFA coated heaters are entirely distinct. A unified operation training mode will result in operators misoperating and accelerating the corrosion and failure of equipment. In this paper, classified training core contents, standardised operation procedures, and forbidden operation red lines for the four heating tubes are established. These can be compiled into a workshop post operation SOP for staff training and assessment.
1. A Common Basic Training Content for All Four Heating Tubes
Colour, structural attributes, and primary corrosion-prone areas of each heating tube comprise the fundamental identification of the material.
General safety operation regulations: Prohibit the over-powering of an empty tank during startup, the rapid impact of cold and high temperatures, the regular exhaustion of accumulated gas in the tube bundle and the recording of regular appearance patrols.
General Operational Requirements for CIP: Clean from low to high temperatures, with gradual heating and cooling, and no abrupt transitions between acid and alkali liquids.
Surface abnormal discolouration, heating power fluctuation, liquid leakage, and pipeline interlock alarm status recording standards comprise the daily patrol checklist.
2. Operation Specifications and Special Training for 316L Stainless Steel Heating Tubes
Primary instruction objectives
The damage mechanism of chloride pitting corrosion, the temperature limit of alkaline cleaning liquid, the flow of passivation maintenance operations, and the method of cleansing weld dirt.
Procedures for standard operations
Startup: First, preheat the medium to 50℃. Subsequently, activate the heating power and regulate the surface power density to 1.0–1.5 W/cm².
CIP cleaning: The temperature of the alkali circulation must not exceed 60℃. Prior to acid descaling, a thorough rinse with clear water should be conducted. The flushing time should be extended at weld dead corners.
Maintenance shutdown: Following the production shutdown, circulate neutral clean water to remove scale, followed by drying. Additionally, conduct offline supplementary passivation every six months.
Absolute prohibition of operation red line
Privately disable the temperature interlock for alkali liquid and operate it at a high temperature for an extended period.
For extended periods of immersion, employ cleaning agents that contain chloride.
Utilise a metal scraper and steel wire brush to refine the welds and tube surface.
Maintain a horizontal installation without any inclination, which will ensure the long-term retention of bubbles on the upper arc.
3. Operation Specifications and Special Training for Pure Titanium Heating Tubes
Primary instruction objectives
Passive film self-repair principle, anti-scratch elevating requirements, aeration online passivation operation, and the irreversible corrosion hazard of the fluoride medium.
Procedures for standard operations
First, activate the pipeline aeration device to guarantee that the medium contains an adequate amount of dissolved oxygen. Subsequently, heat the medium.
CIP cleaning: After cleaning, ensure that aerated water circulation is maintained for 30 minutes to repair minor scratches on the oxide film. The alkali liquid can be maintained at a temperature below 65℃.
Overhaul handling: For disassembly and hoisting, exclusively employ nylon soft slings and plastic gaskets; isolate all carbon steel contact positions with PTFE sleeves.
Absolute prohibition of operation red line
Incorporate any raw materials or cleaning agents containing fluoride into the tank.
Direct contact and friction between a steel wire rope and a titanium tube assembly, as well as an iron wrench.
Long-term shutdown without sealed anti-fluoride isolation storage or full water immersion.
The cancellation of the tube bundle exhaust valve will result in a long-term oxygen-deficient air film coverage.
4. Specifications for Operation and Special Training for Quartz Anti-Corrosion Heating Tubes
Primary instruction objectives
Brittleness thermal shock rupture risk, permanent damage mechanism from alkali etching, low power density operation limit, and shockproof handling requirements.
Procedures for standard operations
Start-up: The heating power is strictly regulated to below 0.8 W/cm², and the temperature rises at a rate of less than 0.5℃/min.
CIP cleaning: Prior to cleaning, all alkali conduits should be completely disconnected. The circulation of disinfectants should be limited to acid and neutral. The pump flow velocity should be reduced to mitigate the impact of liquid flow.
Maintenance of the shutdown: Before discharging the liquid, allow it to cool to room temperature naturally after closure. Additionally, conduct a monthly inspection of the light transmission cracks.
Absolute prohibition of operation red line
To clean the quartz tube bundle, the alkali liquid valve was accidentally opened.
Inject cold water into a hot quartz tube at a rapid pace to facilitate cooling.
Knock, compress, and impact the tube body during the overhaul and transportation process.
Rapid thermal operation with high power, disregarding the surface power density limit.
5. Specifications for Special Training and Operation of PFA Coated Heaters
Primary instruction objectives
Coating high-temperature ageing failure law, scratch penetration hidden danger, slow cooling post-cleaning program, and plastic particle pollution risk for sterile workshops.
Procedures for standard operations
Startup: Enable the over-temperature automatic power-off interlock and restrict the medium long-term operating temperature to less than 100℃.
CIP cleaning: Maintain the temperature of the cleaning liquid below 95℃; initiate a gradual cooling program following high-temperature cleaning, rather than direct cold water flushing; reduce the concentration of hydrogen peroxide by 50%.
Overhaul handling: It is important to avoid the scraping of the coating surface by sharp metal edges, as all contact instruments are made of soft plastic.
Absolute prohibition of operation red line
Disable the temperature interlock to enable the coating to operate at temperatures exceeding 110℃ for an extended period.
Scrape surface scale and dirt with metal hard instruments.
Apply to pharmaceutical fermentation lines that adhere to the highest standards of GMP sterility.
For an extended period, circulate a medium containing a significant number of hard suspended abrasive particles at a high flow rate.
6. Daily Management Rules and Post-Training Assessment
Graded assessment: Operators are required to successfully complete the classified operation examination that corresponds to the heating tube type of their tank prior to commencing their positions. Unqualified personnel are prohibited from conducting independent operations.
Post a reminder card: Place red line cards that specify prohibited operations for each material beside the heating control cabinet for the fermentation tank.
Consistent training: Conduct retraining every six months and incorporate new training content as soon as the production formula or cleaning process is modified.
Traceability of operations: Record abnormal operation, interlock alarm, and misoperation disposal in the equipment daily ledger, and conduct targeted re-training for positions that experience frequent misoperations.
Summary
The fundamental objective of differentiated operation training is to enable operators to comprehend the fatal weak points of each heating tube and prevent man-made harm from the operation source. The core of the titanium operation is fluoride isolation and anti-scratch, while the quartz operation rigorously avoids thermal shock and alkali liquid. The stainless steel operation is focused on alkali temperature control and anti-chloride erosion. The temperature limit and anti-scratch coating protection are the primary focus of PFA operation. The frequency of heating tube failures, the duration of their service life, and the stability of continuous fermentation production can be significantly reduced by standardised classified training and post-operation specifications.