Petrochemical and refinery
The petrochemical and refining industry requires industrial gases for nitrogen purging, welding maintenance, safety and environmental monitoring and process control.
Nitrogen is frequently used to purge the space in crude oil and processed fuel tanks to avoid the ingress of air. The oxygen from air could cause an explosive atmosphere inside the tank resulting in hazardous conditions.
A range of industrial cylinder gases are used for welding and cutting of metals during maintenance and construction operations. Welding equipment such as torches, electrodes and related PPE for safety are also required.
The analytical instrumentation that is used to measure the composition of process streams requires high purity instrumentation gases such as helium for gas chromatography or hydrogen for FID detectors to function. These instruments also require frequent calibration using high precision calibration gas mixtures which are available from the Coregas specialty gases product range.
Flammable gases such as methane or propane and toxic gases such as hydrogen sulphide are abundant on refineries and petrochemical processing plants. It is common to mitigate the risks associated with leaks of these gases with the use of fixed or portable gas detection equipment which is permanently sniffing for leaks. Gas detection devices require frequent testing and occasional calibration using high precision specialty gases mixtures which simulate the toxic or flammable gases to be detected.
Emissions to air from a refinery or petrochemicals facility are unavoidable. Combustion of fuels to generate steam or burning of methane in steam reformer hydrogen generators produces flue gases which are emitted to atmosphere through the refinery smoke stacks. Continuous emissions monitoring systems (CEMS) are installed to measure stack gas flows and ensure that the emissions of potentially harmful gases such as oxides of nitrogen, sulphur dioxide or carbon monoxide are managed within approved limits. These CEMS systems require validation with specialty gas calibration mixtures to prove that their measurements are accurate and therefore that the emissions will not be harmful to the environment or public health.
When entering storage tanks for maintenance or cleaning, the operator will be working in a confined space where the free flow of air might not be possible. It is likely that the space contains residual vapour from various hydrocarbons or nitrogen gas from purging activity. In any case, gas detection PPE should be worn to give notice of any gas risks. It is also often the case that breathing apparatus will be worn where pure clean air is provided to the operator through pipes and into a breathing mask. Such breathing air is often supplied from cylinders because the local compressed air supply will most likely contain traces of oil and will therefore not be suitable for human consumption. These cylinders can either be of a small size that can be carried with the operator, or would remain outside the confined space in larger quantities and the breathing air would be piped into the worker.