Introduction: The Special Characteristics and Extremely High Requirements of Chemical Liquid Level Monitoring
The chemical industry is a vital pillar of the national economy, but its production processes often involve hazardous chemicals exposed to high temperatures, high pressures,
and flammable, explosive, and highly corrosive substances. According to data from the Ministry of Emergency Management, approximately 30% of major safety accidents are
related to uncontrolled liquid levels in storage tanks, reactors, and other equipment. Therefore, reliable and continuous liquid level monitoring of hazardous chemical storage
tanks and reactors is the cornerstone of inherent safety in chemical enterprises. In this field, capacitive liquid level sensors, with their superior corrosion resistance and flexibility, have become irreplaceable safety guardians.
Extreme Challenges Faced by Chemical Liquid Level Detection
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Highly Corrosive Media: Media such as concentrated sulfuric acid, concentrated alkali, and organic solvents place extremely stringent requirements on the materials of the sensor's contact parts.
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Complex Process Conditions: High temperature, high pressure, and processes prone to crystallization and adhesion often lead to the malfunction of traditional instruments.
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Stringent Safety Standards: Specific SIL (Safety Integrity Level) certification is often required, quantifying the reliability requirements of the instruments.
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Explosion-proof Requirements: Monitoring areas are mostly explosive hazardous zones, requiring sensors to possess corresponding explosion-proof certifications (e.g., Ex d/e).
Capacitive Level Sensor Solution: Dual Advantages in Materials and Principles
1.
Excellent Corrosion Resistance: Sensor probes can be made of special materials such as Hastelloy or PTFE (polytetrafluoroethylene) for full encapsulation, easily handling most highly corrosive media.
2.
Anti-adhesion and Non-contact Options: For easily adhering media, non-contact installation can be selected, with the sensor installed on the
outer wall of the tank, completely eliminating measurement inaccuracies caused by scaling and crystallization.
3.
High Reliability Meeting SIL Requirements: Capacitive principle-based sensors have a simple structure, long mean time between failures (MTBF),
and are easily designed to meet SIL2 and even SIL3 safety level requirements through hardware and software.
4.
Intrinsically Safe/Explosion-proof Design: Mature explosion-proof design meets installation requirements in hazardous areas such as Zone 0 and Zone 1.
Core Application Scenarios
• Raw Material/Product Storage Tanks: Monitor the liquid levels of strong acid, strong alkali, and solvent storage tanks, providing high and low level alarms.
• Reactor Level Monitoring: Participate in the interlocking control of the reaction process to prevent overflow or empty reactor operation.
• Intermediate Tanks and Metering Tanks: Enable batch and precise material transfer control.
Key Selection Points
**Importantly define:** Media properties (concentration, temperature), process pressure, explosion-proof requirements, and the required SIL
(Surface Intake Level) rating. Based on this, select the correct wetted materials, structural form, and certification.
