Hydrogen gas plays a pivotal role in refineries and energy production as it contributes to many core operations and processes. The use of hydrogen for industrial purposes has grown dramatically over the past few decades, and future projections indicate that its use will continue to grow on pace with demand for energy. Hydrogen consumption is dominated by petroleum refining, treating metals, producing fertilizer, and processing foods. The increased use of hydrogen also calls for greater abilities to detect hydrogen leaks quickly to prevent hazardous conditions. Therefore, hydrogen gas detection needs to be a priority to protect national property and human life. For this purpose, BARC has developed acatalytic type hydrogen Sensor (Model: TPD-BARC H2-2021) which issuitable for detection in the rangefrom 0.5 to 4 %. Our sensor comprises of a "Transmitter" and a "Digital Monitor". The "Transmitter" consists of a sensing element comprising of Pt-100 coated with Pd, whose temperature is controlled using a circuit. The temperature at the surface of sensor film changes as a function of H2 concentration, which is calibrated and displayed directly in volts on a monitor.

1. H2 gas detection in the range from 0.5 to 4.0%.
2. Faster response and recovery times of ~5 and ~ 180 s, respectively.
3. Zero setting to ensure 0 V in absence of H2 gas and adjustable alarm set points.
4. Exhibits life time of >2 years under operating conditions.

Hydrogen Sensor (Model: TPD-BARC H2-054P) along with the monitor. This sensor is suitable for detection of H2 gas in the range of 0.5 - 4.0%. The sensor comprises of two main parts namely a "Transmitter" and a "Digital Monitor".

1. Transmitter: It consists of sensor head which is a sputtered Pd film on Pt-100 and a temperature-controlled circuit. Both sensor element and temperature control circuit are enclosed in stainless steel housing.
   
   
2. Digital Monitor: The output of the sensor is signal conditioned and transmitted through 4-20 mA converter link. The receiver unit receives the current signal, converts into voltage. This voltage is properly amplified, calibrated and displayed as the percentage concentration of hydrogen, using 3 1/2-digit DPM. The receiver unit also powers the transmitter units. The 4-20 mA current loop helps to keep the sensor more than 300m away from the control room.

Hydrogen Sensor (Model: TPD-BARC H2-054P)

Sensor Element

1. Sensor film : Pd
2. Heater : Pt- 100
3. Electrical leads: Pt wire (dia. –0.1 mm)

Sensor Housing

1. Material : SS-304
2. Housing dimensions : 66 X 43 X 155 mm
3. Sensor head diameter: 28 mm

Digital Monitor

1. Display
1. Voltage calibrated with H2 conc.
2. Alarm set points.
3. Zero setting to ensure 0 V in absence of H2 gas.

Technical Parameters

1. H2 detection range : 0.5–4 %
2. Operating temperature : 150±2°C
3. Response time (time to reach 90% of the total change) : 2 - 5 s.
4. Recovery time (time to reach 10% of the total change) : ~2 - 3 min.
5. Response at 4 % H2 : ~ 4 V
6. Selectivity for H2 (in comparison to NO, C2H5OH, CO2, Cl2, SO2, H2 and NH3 etc.) : Excellent
7. Life time under operating conditions : > 2 years

1. Heavy Water Plants (DAE)
2. Hydro-desulfurization and hydrocracking operation in refineries
3. Ammonia production
4. Metallic ore reduction
5. Rotor coolant in large electrical generator
6. Battery storage
7. H2 fuel cells

1. Sensor fabrication
1. RF/DC Sputtering system for Pd film deposition
2. Pd targets
3. Electronic components like Pt-100, OPAMPS etc.
4. Fabrication facility for sensor and monitor housing
5. Ultrasonic transducer for calibration of sensors
6. Mass flow controllers
7. H2 and air generators
2. Other requirements
1. PC or Laptop
3. Space
1. A room of 3×3 m2 floor area is needed to accommodate above mentioned facilities.

2 Numbers

1. 1 person with bachelor degree in Physics/Chemistry
2. 1 person with diploma in Electrical/Electronics.

1. Integrated Hydrogen gas sensing device based on sputter-deposited Pd thin films, N. Datta, S. Samanta , S. Bhattacharya , A. Pathak, Niranjan S. Ramgir, Kailasa Ganpathi , M. Kaur , K. P. Muthe, A. K. Debnath , D. Bhambure, P. Abichandani, BARC News Letter, May-June 2021 issue, Page 29-33.