Gas Density/Hydrogen Purity Analyzer

Advanced Gas Density, Hydrogen Purity & Replacement Concentration Meters

Direct gas density measurement using Yokogawa's proprietary multi-mode oscillation technology.
Suitable for a wide range of process gases, excluding highly corrosive gases. Fast response and stable performance help improve safety, optimize operations, and reduce operating costs.

Proven across power generation, oil and gas, petrochemical, steel, chemical, and other process industries, the technology is now expanding into carbon-neutral applications such as water electrolysis and methanation.

In addition to density, monitors gas concentration, molecular weight, specific gravity, hydrogen purity, and replacement concentration.

Highlights

No dedicated analyzer for each gas, measuring binary gas mixing ratios with a single instrument.
Detect process changes early.
Gas concentration*, molecular weight, specific gravity, calorific value, and more can be calculated from density measurements.
(*: For known binary gas mixtures)
Built for stable, low-maintenance operation with minimal drift from oil mist, dust, and moisture.

Applications

Safety and Reliability

Hydrogen purity monitoring
Gas Replacement monitoring

Process Optimization

Gas mixing ratio control
Fuel quality monitoring
Average molecular weight measurement

Applications

Industries

Power Generation, Renewable Energy, Chemicals, Steel, Oil & Gas, and More

Use Cases

Gas Concentration Monitoring from Density Measurement

Hydrogen purity and replacement gas concentration monitoring in hydrogen-cooled generators
Cross-leakage monitoring in water electrolysis processes
Composition monitoring in methanation processes

Average Molecular Weight Measurement

Off-gas molecular weight measurement in petroleum refining processes

Use Cases

Gas Density Meter GD80, GD802G, GD802S

Fast-response gas density measurement for safe and stable operation. More than density, monitor gas concentration, molecular weight, specific gravity, hydrogen purity, and replacement concentration.
GD402 Analyzer

The Model GD402 gas density analyzer and Model GD40 detector not only provide continuous measurement of gas density, but also several other valuable parameters, including specific gravity and molecular weight. The Model GD402 is a rugged microprocessor-based converter designed in two versions to meet both general area and explosion-proof application requirements.
GD40 Detector

The GD40 detector is designed for intrinsically safe and flameproof, explosion protected applications. It is designed to be virtually maintenance free for all accepted applications.

Fast Response, Stable Performance

Advantages of Yokogawa's Proprietary Multi-Mode Oscillation Technology for Safe and Efficient Operations

Fast response enables rapid detection of process changes.
Minimal drift from oil mist, dust, and moisture ensures stable measurement.
Easy sensor cleaning and recovery, even after contamination.

Measurement Principle: What is Multi-Mode Oscillation Technology?

Two pairs of piezoelectric elements for drive and detection are attached on four points of a thin-wall cylindrical resonator. A platinum temperature sensor is mounted to the density sensor.
The sample gas from inlet passes over the outside of the thin-walled cylindrical resonator and is exhausted at the gas outlet.

Measurement Principle: What is Multi-Mode Oscillation Technology?

How Density Determines Concentration

The graph illustrates the relationship between gas density and concentration in a binary gas mixture.
Each gas has unique density characteristics, allowing concentration to be determined from density measurement. This enables accurate monitoring of gas concentration, hydrogen purity, and gas replacement conditions.

Glossary

What Is Methanation?

Methanation is the process of producing methane from carbon dioxide (CO₂) and hydrogen (H₂). It is gaining attention as a key technology for utilizing renewable hydrogen.