The use of natural gas, of which methane is the principal component, is increasing worldwide. It also has many industrial uses, such as the manufacture of chemicals like ammonia, methanol, butane, ethane, propane and acetic acid; it is also an ingredient in products as diverse as fertilizer, antifreeze, plastics, pharmaceuticals and fabrics. With continuous industrial development, there is an increase in the risk of harmful gas being released. Although these emissions are controlled, there however, may be operations that involve the handling of hazardous gases in which lapses in preventive maintenance such as ensuring there are no faulty pipelines or equipment, can result in terrible outcomes.
What are the dangers and ways of preventing gas leaks?
Natural gas is transported in several ways: through pipelines in gaseous form; as liquefied natural gas (LNG) or compressed natural gas (CNG). LNG is the usual method for transporting the gas over a long distance, i.e., across oceans, whilst CNG is ordinarily transported using a tanker truck over short distances. Pipelines are the preferred transport choice for long distances over land (and sometimes offshore). Local distribution companies also deliver natural gas to commercial and domestic users across utility networks within countries, regions and municipalities.
Regular maintenance of gas distribution systems is essential. Identifying and rectifying gas leaks is also an integral part of any maintenance programme, but it is notoriously difficult in many urban and industrial environments, as the gas pipes may be located underground, overhead, in ceilings, behind walls and bulkheads or in otherwise inaccessible locations such as locked buildings. Until recently, suspected leaks from these pipelines could lead to whole areas being cordoned off until the location of the leak was found.
Modern technologies are becoming available that allow for remote detection and identification of leaks with pinpoint accuracy. Hand-held units, for example, can now detect methane at distances of up to 100 metres, while aircraft-mounted systems can identify leaks half a kilometre away. These new technologies are reshaping the way natural gas leaks are detected and dealt with.
Remote sensing is achieved using infrared laser absorption spectroscopy. As methane absorbs a specific wavelength of infrared light, these instruments emit infrared lasers. The laser beam is directed to wherever the leak is suspected, such as a gas pipe or a ceiling. Due to some of the light being absorbed by the methane, the light received back provides a measurement of absorption by the gas. A useful feature of these systems is the fact that the laser beam can penetrate transparent surfaces, such as glass or Perspex, so there is a possibility to test an enclosed space prior to entering it. The detectors measure the average methane gas density between the detector and target. Readings on the handheld units are given in ppm-m (a product of the concentration of methane cloud (ppm) and path length (m)). This method allows for methane leak to be found quickly and confirmed by pointing a laser beam towards the suspected leak or along a survey line.
As there are several risks when using gas such as explosion from damaged, overheated or poorly maintained cylinders, pipes equipment or appliances. There is also the risk of carbon monoxide poisoning and burns caused by contact with flame or hot surfaces. By implementing real-time gas leak detection, industries can monitor their environmental performance, ensure better occupational health, and eliminate potential hazards for optimum safety. Also, early detection of gas leaks can trigger concerned engineers to curtail the spread and keep a safe environment for better health and safety.