1. Description:

The Honeywell 2108B2003N is a Searchpoint Optima Plus Point Infrared (IR) Flammable Gas Detector, specifically factory-calibrated for Ethylene gas detection and holding ATEX certification. It is a state-of-the-art fixed point gas detector designed for continuous, non-contact monitoring of ethylene in potentially explosive atmospheres. While the Optima Plus series can detect a wide range of hydrocarbons, this specific model (2108B2003N) is optimized for the detection of ethylene, a crucial gas in many petrochemical processes. It employs advanced infrared absorption technology, which provides significant advantages over traditional catalytic bead detectors in harsh industrial environments. This model features a robust 316 stainless steel housing and provides a versatile 4-20mA output (auto-sensing sink or source), allowing for direct and flexible integration with industrial control systems.

2. Application Scenarios:

Consider a large petrochemical plant involved in the production of polyethylene, a widely used plastic. Ethylene is the primary feedstock, and any undetected leak can lead to catastrophic explosions. The environment around polymerization reactors, cracker units, and ethylene storage tanks is constantly under high risk. The Honeywell 2108B2003N Searchpoint Optima Plus detectors would be strategically deployed throughout these high-risk areas. Their precise calibration for ethylene ensures accurate and rapid detection of leaks. Unlike catalytic bead detectors, which can be poisoned by certain chemicals or require oxygen to function, the Optima Plus is immune to such issues and performs reliably even in inert atmospheres. This ensures continuous, fail-safe monitoring of ethylene, allowing for immediate alarm activation, process shutdown, and emergency response, directly addressing the critical pain points of ensuring safety and preventing explosions in complex and highly volatile petrochemical operations.

3. Parameter:

Main Parameters Value/Description Product Model: Honeywell 2108B2003N Manufacturer: Honeywell Analytics (part of Honeywell) Product Category: Fixed Point Infrared Flammable Gas Detector Product Line: Honeywell Searchpoint Optima Plus Sensor Type: Point Infrared (IR) absorption Gas Type Detected: Ethylene (specifically calibrated for) Measuring Range: 0-100% LEL (Lower Explosive Limit) for Ethylene Output Signal: 4-20mA analog output (auto-sensing sink or source); Optional HART® over 4-20mA (with specific versions); Optional Multidrop Modbus RS485 (via XNX or DX100(M) transmitter) Inhibit Signal: 1-3mA (Default 2mA) Warning Signal: 0-6mA (Default 3mA) Fault Signal: 0mA (HART® units adjustable to 1mA) Over Range Signal: 20-21.5mA (Default 21mA) Supply Voltage: 18-32V DC (24V DC nominal), < 4.5W max power consumption Response Time (T90): Less than 4 seconds (typically < 3 seconds for T50) Operating Temperature: -40°C to +65°C (-40°F to +150°F) Housing Material: 316 Stainless Steel (electro-polished) Ingress Protection: IP66 / IP67 (dust tight and protected against powerful water jets/immersion up to 1m) Weight: Approximately 1.6 kg Thread Type: M25 thread spigot (for ATEX versions) Approvals: ATEX, IECEx, UL, FM/CSA, MED (Marine Equipment Directive), CCCF & CU-TR Ex (specific to the 2108B2003N configuration, ATEX is confirmed). Safety Integrity Level (SIL): IEC61508 Safety Integrity Level 2 (independently assessed by TÜV) Key Features: Ethylene-specific calibration, failsafe operation, fast response, reduced routine maintenance, immune to catalytic poisons, long operating life, works in inert atmospheres, self-compensating optics, dynamic heating control (for condensation), integral event logging, advanced diagnostics.

4. Technical Principles and Innovative Values:

The Honeywell 2108B2003N Searchpoint Optima Plus (Ethylene) leverages cutting-edge technical principles and offers significant innovative value, particularly due to its specific calibration for ethylene:

• Innovation Point 1: Ethylene-Specific Dual-Compensated Infrared Absorption: The Optima Plus operates on a sophisticated dual-path (often 4-channel) infrared absorption principle. It uses two specific IR wavelengths: a measurement wavelength precisely selected for strong absorption by ethylene, and a reference wavelength that is not absorbed by ethylene. The innovative value for the 2108B2003N lies in its factory calibration and optimization specifically for ethylene’s unique IR absorption characteristics. This precise tuning ensures highly accurate and specific detection of ethylene, while its dual-channel design continuously compensates for environmental factors (dust, fog, rain) and internal component drift, providing unparalleled stability and a critical fail-to-safe operation. If the optical path is severely blocked or a fault occurs, the detector defaults to a fault signal, eliminating the risk of undetected failures.
• Innovation Point 2: Inherent Immunity to Poisons and Oxygen Deficiency (Crucial for Ethylene Production): Ethylene production and handling environments often contain catalysts, byproducts, or inerting gases that would severely compromise or fail traditional catalytic bead detectors. The Optima Plus’s infrared principle is a profound innovation because it does not rely on a chemical reaction or the presence of oxygen for detection. This makes the 2108B2003N inherently immune to “poisoning” by silicones, sulfur compounds, chlorinated hydrocarbons, and operates perfectly in oxygen-deficient or inert atmospheres (e.g., nitrogen-purged areas). This immunity guarantees sustained accuracy and reliability, dramatically extending sensor lifespan and reducing costly maintenance and false alarms in demanding chemical processes.
• Innovation Point 3: Advanced Diagnostics and Minimized Maintenance: The 2108B2003N incorporates sophisticated internal diagnostics that continuously monitor the detector’s operational health, including optical cleanliness and alignment. It provides early warnings if optics become contaminated, allowing for proactive cleaning before a fault occurs. Features like dynamic heating control actively prevent condensation buildup on the optics, ensuring clear visibility in changing environmental conditions. This level of self-monitoring and proactive diagnostics, combined with the inherently stable IR technology, drastically reduces the need for routine maintenance (e.g., less frequent bump tests and calibrations compared to catalytic sensors) and minimizes false alarms, maximizing detector uptime and operational integrity for critical plant assets handling ethylene.

5. Application Cases and Industry Value:

In a polymer manufacturing plant specializing in polypropylene, ethylene (a common feedstock) is used in significant quantities. A major risk is an ethylene leak near a hot process, which could lead to a rapid and devastating deflagration or explosion. The plant installed Honeywell 2108B2003N Searchpoint Optima Plus (Ethylene) detectors at various critical points: around the monomer storage tanks, along transfer lines, and within the vicinity of polymerization reactors. The specific calibration to ethylene allowed for highly accurate and rapid detection of even small leaks. The detector’s resilience to potential catalytic poisons present in the chemical environment, and its ability to operate reliably despite temperature fluctuations, ensured continuous protection. Upon detection, the system integrated with the plant’s safety instrumented system (SIS) to trigger alarms, activate emergency ventilation, and initiate emergency shutdown sequences. This proactive and highly reliable gas detection system directly contributed to significantly enhanced worker safety, reduced the risk of major industrial accidents, prevented substantial economic losses from plant damage and downtime, and ensured compliance with stringent safety regulations.

6. Related Product Combination Solutions:

The Honeywell 2108B2003N is a robust point detector but typically forms part of a larger integrated gas detection system:

• Honeywell XNX Universal Transmitter (recommended accessory): While the 2108B2003N provides a 4-20mA output, integrating it with an XNX transmitter enhances functionality. The XNX offers a local display for real-time readings and status, local alarm relays, and enables additional digital communication protocols like HART or Multidrop Modbus RS485, facilitating superior integration with plant DCS/PLC systems.
• Honeywell Touchpoint Plus Controller / Multi-Channel Control Systems: For centralized monitoring of multiple Optima Plus detectors across a facility, a multi-channel controller (e.g., Touchpoint Plus, or larger safety controllers like Safety Manager) can consolidate alarm management, display readings, and provide a single interface to the plant’s main control system.
• Calibration Gas (Ethylene) and Flow Regulator: Essential tools for periodic functional “bump tests” (to confirm the detector’s response) and full calibrations to ensure the detector’s ongoing accuracy and compliance. A certified test gas specifically for ethylene at a known LEL concentration is crucial.
• Remote Gassing Cell (RGC) / Weather Protection Housing: Optional accessories that can be fitted to the detector. An RGC allows for functional gas testing without needing to directly access the detector, simplifying maintenance in difficult-to-reach or hazardous locations. A weather protection housing provides enhanced protection against severe environmental conditions (e.g., heavy rain, direct sunlight, wind-blown dust).
• Mounting Kits and Junction Boxes: Required for secure and certified installation in hazardous areas, ensuring compliance with local electrical codes and robust physical placement.
• Plant DCS/PLC System / Safety Instrumented System (SIS): The ultimate destination for the 4-20mA or digital output signals from the Optima Plus. This allows for comprehensive monitoring, alarm management, data logging, trending, and integration into the plant’s overall safety logic and emergency shutdown systems, crucial for managing ethylene hazards.

7. Installation, Maintenance, and Full-Cycle Support:

Installation of the Honeywell 2108B2003N involves securely mounting the detector to a suitable surface, ensuring its optical path is clear and positioned to optimally detect potential ethylene plumes. Electrical wiring from the detector (via a certified hazardous area cable gland, typically M25 threaded for ATEX versions) connects to a local junction box or directly to a control panel, strictly adhering to all relevant hazardous area electrical codes (e.g., ATEX EN60079 series). Proper earthing/grounding of the detector and associated metalwork is crucial for safety and signal integrity. Commissioning typically involves powering up the unit, allowing for a brief stabilization period, and then performing initial calibration (usually a zero calibration against fresh air and a span calibration using a known concentration of ethylene test gas).