PEFTEC 2017 - Abstract

Abstract Title: Bio-methane quality supervision with all-in-one continuous monitoring solution
Abstract Type: Oral
Presenter Name: Mr Louis Vivola
Co-authors:Mr Mickaël Gezat
Company/Organisation: Chromatotec
Session Choice: Online & Process Monitoring

Abstract Information :

Bio-Methane market is currently experiencing a rapidly changing environment through the energy mix. In natural gas field, bio-methane qualification is an important and increasing challenge, just as odorants and calorific value control is. Solutions for C1C6+ hydrocarbons and odorant compounds monitoring are based on continuous measurement of the process. To control performances and monitor C1C6+, a gas analyzer using a Thermal Conductivity Detector (TCD) is the perfect tool to detect and quantify hydrocarbons from C1 to C6+. Thanks to isothermal mode, it is possible to provide calorific value and WOBBE index to the end user on automatic mode.

For natural gas characterization, it is necessary to quantify hydrocarbons as iso- or linear propane, butane, pentane (iso and linear) or hexane. When hexane is not present, performances and cycle time can be increased with reduce cycle time. In term of functions, some individual alarms may be defined per type of molecule. Thanks to software capabilities, C1C6+ group has been created as additive parameter to check global profile and be warned when significant changes of concentration are observed. Users can check results from dedicated Supervision center offering results at a glance. The 4-20 mA output option allows to adjust the process by direct integration of the signal on the process.

For complete monitoring of the process, pipeline integrity management should be at stake. During biogas injection on the pipeline, according to its quality, H2S and Total Sulfur level should be monitored quickly. If H2S or Total Sulfur concentration exceeds requiring level, it could be necessary to stop Biogas injection until required level is achieved.

Being colorless with strong natural odor due to fermentation, Biogas can naturally contains sulfur compounds as H2S and Mercaptans with strong odorant power which can also produce sulfuric acid in case of humidity, which can damage pipelines. Odorization control is then an important issue; it is necessary to analyze odorant compounds downstream and upstream, to identify naturally occurring compounds and injected ones and monitor losses in the pipeline. The sulfur analyzer working with only nitrogen is linear and able to track concentration levels from ppb to % in automatic mode allowing versatile application with capabilities to work in hazardous areas (ATEX, CSA certification).

Biogas can also contain mono terpenes as limonene, Alpha-pinene of beta-pinene that can cover sulfur compounds odor injected in natural gas and biogas. These mono terpenes should then be analyzed to prevent from masking risk of the odorant compounds. High level analysis of all odorant sulfur compounds, natural or injected, at ppt to ppm level is a major challenge.