Properties and detection of hydrogen sulfide

Hydrogen sulfide, with molecular formula of H2S and molecular weight of 34.076, is a kind of flammable acid gas under standard conditions, colorless, with odor of rotten eggs at low concentration and toxic. Its aqueous solution is hydrogen sulphuric acid. Molecular weight is 34.08, vapor pressure is 2026.5kpa/25.5 ℃, flash point is < - 50 ℃, melting point is - 85.5 ℃, boiling point is - 60.4 ℃, relative density is (air = 1) 1.19. 

It is soluble in water, easily soluble in alcohols, petroleum solvents and crude oil. The ignition point is 292 ℃. Hydrogen sulfide is a kind of inflammable and dangerous chemicals, which can form explosive mixture when mixed with air. It can cause combustion and explosion in case of open fire and high heat. Hydrogen sulfide is an important chemical raw material.

Physical properties of hydrogen sulfide：

1. Colorless

2. It has typical odor of rotten eggs (when the concentration is in the range of 0.13-4.6ppm, 

it can smell rotten eggs, but when the concentration is more than 4.6ppm, it has no smell).

3. Molecular weight: 34.08

4. It is soluble in water, carbon disulfide, petroleum solvent and crude oil.

Chemical properties of hydrogen sulfide：

1. It is combustible, and the flame is blue when burning, and produces toxic gas SO2

2. Explosion limit in air: 4.3% ~ 45.5% (volume ratio)

3. The lethal concentration of H2S is 500ppm

4. It is highly corrosive to steel.

Hydrogen sulfide gas detection

The highly toxic and explosive characteristics of hydrogen sulfide make it necessary to prevent leakage in industrial production or transportation. Now other detectors are used in industrial production to monitor the concentration of toxic and harmful gases. The fixed hydrogen sulfide gas detector can monitor 24 hours in real time, which is widely used in industrial production, petroleum and petrochemical fields.