Odorantization

Odorantization is the process of adding odorant compounds to otherwise odorless gases to provide a detectable smell for safety and leak detection. It is commonly applied to natural gas, propane, and other fuel gases before or during their distribution to consumers. The practice helps identify leaks quickly, facilitating responders’ actions and reducing the risk of fires or explosions.

The most widely used odorants are sulfur-containing compounds called mercaptans, with tert-butyl mercaptan and ethyl mercaptan being among the common choices. Other sulfur-containing or tertiary compounds may be used depending on gas composition, regulatory requirements, and material compatibility. Odorant selection and dosing are regulated by national and regional standards and utility codes to ensure a reliable odor while avoiding adverse effects on equipment or processes. In many jurisdictions, natural gas is required to be odorized before entering the public network.

The odorization process typically involves injecting a controlled amount of odorant into the gas stream using metering pumps and odorant-dosing systems. Factors such as gas composition, pressure, temperature, distance from the odorization point, and potential odorant loss in transmission are considered to determine appropriate dosing. Odorants should remain effective throughout transmission and not cause excessive corrosion or material degradation. Aging or interactions with treatment processes can reduce odor intensity, necessitating periodic monitoring and maintenance.

Public safety relies on odorant perception, but odor alone is not sufficient for safety; some individuals may have diminished sensitivity to certain odorants, and odor can be masked in non-ventilated areas. Therefore, odorization is complemented by gas detectors and contingency planning.