Safe and Reliable Sulphur Monitoring at ppb Level in Hazardous Areas

In 2009, Chromatotec (France) launched their first version of the MEDOR  Exp cabinet specifically for sulphur monitoring in hazardous areas. Initially, the MEDOR analyser attained Class 1 Div 2, group C&D USA certification for operating in hazardous areas. It received CSA International recognition shortly afterwards.

Chromatotec then offered  a full package including MEDOR and ChromENERGY for gas quality control dedicated to petrochemistry, refineries and gas storage areas where ATEX Zone 2 Ex II 3G Ex pz IIC T4 is required. The MEDOR unit can detect sulphur compounds at trace levels whilst the ChromENERGY allows its users to quantify C1-C6+ Hydrocarbons and provides simultaneous Calorific Power Index value measurements. Results are obtained at a glance with VISTACHROM software installed on a unique embedded computer.

Currently, Chromatotec’s analytical technology is under process to obtain higher certification level for ATEX and CSA. The Exp cabinet is protected by continuous flow with an X or Z purge system certified for Zones 1 and 2 respectively. This purging system includes a pressure regulator with a flow restrictor to control the inlet dilution. A flow controller is located at the valve outlet to validate the flow out of the cabinet. The cabinet is pressurised and diluted continuously.

An IP 66 class waterproof case allows the use of the unit in environments in which their is potential for a direct ingress of water to the unit  and  reduces the instrument air consumption volume needed for continuous dilution. H2S, mercaptans and total sulphur can be analysed by MEDOR Exp with only nitrogen required for analysis and integrated calibration.

One of the main advantages of MEDOR is that there are no additional hazardous area created within the analyser as can be the case with hydrogen or air presence and a flame. The worst case is taken into account to calculate the dilution flow to stay under the explosive level. If pressure inside the cabinet is not higher than ambient pressure, the power is switched off by the X-purge system. For service there is a bypass key to open the cabinet without effecting pressure inside.