Fibre-optic, temperature measurement in process engineering
The primary considerations in the design and operation of processing facilities are safety and protecting the environment. Both concerns are dependent upon to maintaining the integrity of the many vessels and lines containing potentially hazardous chemicals, and the two most critical parameters affecting these containment devices are temperature and pressure. It is absolutely essential to continuously monitor and record these critical parameters to guarantee safe operation under optimum processing conditions, and fibre optic temperature measurement has proven the most suitable technology for that purpose in many different type of processes.

In power stations, spatially-distributed, fibre-optic temperature measurement enables the monitoring, control and efficient operation of components such as filters, boilers, burners and pipes.

LIOS fibre optic based measuring systems are ideally suited for use as hot-spot detectors for high temperature, refractory-lined process reactors and vessels such as gasifiers and gas coolers. It is also particularly appropriate when installed as a leak detector on insulated plant components such as pipes, pipe fittings and containers, etc.

The suitability of fibre optics for temperature monitoring on apparatus with protective heat-insulation walls, which means harsh operating conditions, has been successfully demonstrated on dozens of vessels world-wide, including a project involving a high-temperature Winkler (gasifier) plant in an ultra-modern IGCC power station.  

Three dimensional software, colour-coded according to temperature, converts the linear temperature data generated by the fibre into a realistic visual display that clearly highlights hot spots on the skin of the vessel. Thus the local temperature increase in the curved area of the device, caused by the high degree of stress exerted by the flow of hot gas, can be visually monitored by operators. The software also allows for pre-set temperature limits with audio and visual alarm functions.

In chemical and petrochemicals plant, materials of widely differing types are routinely moved and processed, often at high temperature and under high pressure. Both the properties of many of these materials and the processing steps which take place in these plants are potential sources of danger. Toxic materials and in particular inflammable and explosive substances, as well as those mixtures of compounds resulting from exothermic chemical reactions, present particular dangers, and sections of the plant where these products are present require continuous monitoring.

It is in these high-risk areas that LIOS-technology, featuring spatially-distributed, temperature-measuring capabilities contributes to safety significantly. For example, LIOS OTS technology, has been successfully employed to monitor the outer shell of high-pressure, high-temperature reactors (gasifiers) in synthetic-natural-gas plants. Special, high-temperature, sensor cable is attached to the vessel in such a way as to provide maximum spatial coverage that will identify and precisely locate developing hot spots at an early stage. Evolving hot spots on refractory brick lined vessels are an early indicator that the lining is deteriorating, and early warning gives operators time to take mitigative action before the walls fail catastrophically. The resultant damage that would otherwise lead to expensive plant downtime can therefore be avoided. 

Fibre has been successfully used to monitor for hot spots on other types of high temperature, refractory lined vessels such as thermal oxidizers among others..

Because it can be utilised in radioactive, chemically-aggressive and high pressure environments, and in situations where there is a danger of explosion, the spatially-distributed, fibre-optic, LIOS-technology sensor is an ideal temperature-measuring system for critical areas in processing plants.