HK-128W Hydrazine Online Analyzer by Huake Instrument
| Brand | Huake Instrument |
|---|---|
| Model | HK-128W |
| Measurement Principle | Photometric (450 nm LED-based colorimetric assay) |
| Range | 0–100 µg/L |
| Display | 5.7″ 320×240 dot-matrix LCD with bilingual (Chinese/English) menu |
| Measurement Cycle | Programmable 5–60 min per channel |
| Accuracy | ±2% FS |
| Repeatability | ≤1% |
| Baseline Drift | Compensated via blank calibration |
| Sample Flow Rate | 150–300 mL/min |
| Sample Temp. Control | Up to 50 °C |
| Reagent Temp. Control | Up to 50 °C |
| Reagent Consumption | ≤5 L/30 days (cycle-dependent) |
| Output | 4–20 mA (isolated), RS485 standard, HART/Profibus optional |
| Power | AC 220 V ±10%, 50 Hz, max. 240 W |
| Dimensions | 450 × 690 × 225 mm (W×H×D) |
| Weight | 22 kg |
| Compliance | Designed for continuous operation in industrial process water monitoring environments |
Overview
The HK-128W Hydrazine Online Analyzer is an industrial-grade photometric analyzer engineered for continuous, real-time quantification of hydrazine (N₂H₄) in ultrapure and process water streams. It employs a stable 450 nm monochromatic LED light source and a patented integrated optical cell design—where reagent dosing, mixing, reaction incubation, and absorbance measurement occur within a single, thermally stabilized flow path. This architecture minimizes interferences from ambient temperature fluctuations, particulate scatter, and photometric drift. The instrument operates on the principle of colorimetric hydrazine detection, wherein hydrazine reacts with p-dimethylaminobenzaldehyde (DMAB) under acidic conditions to form a yellow azine derivative, measurable at 450 nm. Designed for deployment in high-reliability applications—including boiler feedwater monitoring in thermal power plants, condensate polishing systems, and catalyst protection loops in petrochemical refineries—the HK-128W delivers trace-level sensitivity (sub-100 µg/L range) with metrological stability suitable for regulatory compliance reporting.
Key Features
- Integrated photometric module with patented one-chamber reaction cell—eliminates cross-contamination and reduces maintenance intervals
- Thermal stabilization of sample stream, optical path, and reagent reservoir (all independently controllable up to 50 °C) to suppress temperature-induced signal variance
- High-precision diaphragm metering pump with chemical-resistant wetted parts (EPDM/PFA), delivering <±1% volumetric accuracy across pH 1–12
- Programmable multi-channel operation (1–6 channels), with independent cycle timing (5–60 min) and auto-switching logic
- Dynamic blank compensation algorithm that corrects for baseline drift without manual zeroing or solvent flushes
- Multi-point calibration support (up to 5 points) with user-defined concentration values, enabling non-linear response mapping per application requirement
- Comprehensive self-diagnostic suite: real-time monitoring of valve actuation, pump stroke integrity, sensor voltage offsets, and optical path transmittance decay
- USB interface for secure data export (CSV format), firmware updates, and configuration backup—fully auditable per GLP traceability requirements
Sample Compatibility & Compliance
The HK-128W accepts liquid samples meeting ASTM D4582-22 specifications for ultrapure water: suspended solids ≤5 µm (no colloidal content), temperature 5–50 °C, pressure ≤14 kPa, and flow rate 150–300 mL/min. It is compatible with common hydrazine assay chemistries compliant with ISO 15578:2018 (Water quality — Determination of hydrazine — Spectrophotometric method) and USP (Water Conductivity and Total Organic Carbon). While not certified to IEC 61508 SIL2 or ATEX, its robust aluminum chassis, IP54-rated enclosure, and galvanically isolated analog outputs meet EN 61326-1 for electromagnetic compatibility in industrial settings. Data logging and alarm event timestamps comply with FDA 21 CFR Part 11 when used with validated third-party SCADA platforms.
Software & Data Management
The embedded firmware supports local configuration via touchscreen interface and remote access via Modbus RTU over RS485. All measurement records—including raw absorbance, calibrated concentration, temperature logs, calibration history, and diagnostic flags—are stored in non-volatile memory (≥12 months at 1-min sampling interval). Historical trend curves are renderable directly on the display or exportable via USB for post-processing in Excel or MATLAB. Optional HART or Profibus DP-V1 integration enables seamless connectivity to DeltaV, PCS7, or Emerson DeltaV DCS systems. Audit trails record operator actions (e.g., calibration start/end, parameter changes), supporting ISO/IEC 17025 laboratory accreditation workflows.
Applications
- Boiler feedwater hydrazine residual control in fossil-fueled and nuclear power generation facilities
- Monitoring hydrazine scavenger dosage in once-through steam generators and supercritical units
- Quality assurance in pharmaceutical purified water (PW) and water for injection (WFI) distribution loops where hydrazine may originate from deaerator corrosion inhibitors
- Process water surveillance in ethylene oxide production and hydrogenation catalysis units
- Environmental compliance testing for hydrazine discharge limits in refinery wastewater pretreatment streams
FAQ
What is the minimum detectable hydrazine concentration?
The lower limit of quantitation (LLOQ) is 2 µg/L, defined as signal-to-noise ratio ≥10 under typical operating conditions.
Can the HK-128W be used with alternative reagents?
Only reagents formulated for DMAB-based hydrazine assays and validated for thermal stability at 50 °C are recommended; substitution voids calibration validity and warranty coverage.
Is remote calibration possible?
Yes—calibration can be initiated and monitored remotely via RS485; however, physical standard introduction requires manual access to the reagent manifold.
How often does the optical window require cleaning?
Under normal operation with filtered feedwater, cleaning is required every 6–12 months; the diagnostic system alerts users when optical transmission falls below 92% of baseline.
Does the analyzer support automatic dilution for out-of-range samples?
No—sample dilution must be performed externally; the HK-128W is optimized for direct measurement within its specified 0–100 µg/L linear range.

