odorization

Odorization is the process of adding odorant compounds to otherwise odorless gases, most commonly natural gas and liquefied petroleum gas (LPG), to impart a detectable smell that helps identify leaks. The practice improves safety by enabling consumers and operators to notice gas leaks before they reach dangerous concentrations. Odorants are typically sulfur-containing compounds such as tert-butyl mercaptan (TBM) and ethyl mercaptan, sometimes plus disulfides or other additives. These substances are chosen for detectability, chemical stability, compatibility with pipeline materials, and relatively low toxicity at the amounts used. Because odorant performance can vary with temperature, humidity, gas composition, and flow, utilities regulate and monitor injection to maintain a target odor concentration, often described in odor units per cubic meter or by an odor intensity guideline.

In practice, odorization is achieved with continuous injection at controlled rates, adjusted according to gas flow and network conditions. Odorant is stored in dedicated tanks and dosed through metering pumps into the gas stream either at a central station or at multiple injection points along the distribution network. The goal is a consistent odor throughout the system, with some allowance for odor fading in long-distance sections or near certain materials.

Challenges include odor fading due to adsorption, reactions, or dilution, and potential material compatibility issues or consumer sensitivities. Regulations in many countries require a minimum odor level, specify approved odorants, and mandate monitoring and reporting to ensure safety.