How to Control Biomethane Trace Compounds? Focus on Terpenes

Transcription

1 How to Control Biomethane Trace Compounds? Focus on Terpenes Etienne BASSET ENGIE - CRIGEN Research and Innovation Center In Gas and New Energies Saint-Denis La Plaine - France

2 Gas quality measurements in CRIGEN Analyzers : Optical analyzers : TDLAS, CRDS, OFCEAS µgc-tcd - GC-PFPD HPLC - GC-FID GC-MS Technical skills : Method development and validation Sampling Natural gas quality Other compounds: CO2, N2 Trace compounds: Sulfur compounds, VOCs, PAHs, O2, etc. Methane Ethane Propane Butane Pentane For characterization of biogas, biomethane, syngas and natural gas. Billing issues, safety issues, grid maintenance 2

3 Summary Context The French context of bioenergy and biomethane injection New trace compounds to monitor: focus on Terpenes How to control terpene in biomethane? Assessment of online chromatography device Development of a dedicated method to quantify Terpenes in biomethane by TDS- GC-MS Conclusion & Outlooks 3

4 French context for bioenergy and biomethane Technical maximum potential (2050) 3 3G Microalgae On site production and CO 2 recycling R&D needs Concept proof France 23 TWh Europe 2 2G Gasification/methanation Lignocelulosiqc Biomass (Woody, ) Pilot scale 257 TWh > 560 TWh ~ 1000 plants 1 Anaerobic digestion/biogas Organic waste (municipal, industrial ) Available 185 TWh > 500 TWh ~ plants Biomethane energy carrier potential

5 French context for bioenergy and biomethane Portfolio of Gas Supply (2050) Towards 50% of Green Gases into the gas grid? Gas scenario from French Energy Agency with a strong reduction of primary energy consumption for the transportation sector 53% 6% 28% 13% Biomethane from methanisation Biomethane from gasification and methanation Power-to-Gas from hydrogen produce from excess of renewable electricity Natural Gas A High potential to valorize: 108 TWh of renewable gases in the gas grid in 2050? 64,4 TWh from anaerobic digestion 30 TWh from gasification and methanation 14 TWh from hydrogen produced from excess of renewable electricity 5

6 Biomethane from biogas production Biogas from : Anaerobic digestion of wastes from different origins Landfill gases Agricultural wastes Sludges from WWTP Households wastes Biogas and biomethane composition depend on : The biomass used The methanisation process The gas treatment process In 2014: 6 sites injected biomethane into the French distribution gas grid 6

7 Biogas and Biomethane composition Biogas Gas treatment Upgrading Biomethane Example of biogas composition from anaerobic digestion processes Component Content in Biogas CH % CO % N 2 < 5 % O 2 < 0,5 % Example of biomethane composition Component Content in Biomethane CH 4 > 90 % CO 2 < 2,5 % N 2 < 5 % O 2 < 0,5 % H 2 S 0,01 to 1 % H 2 S < 5 mgs/scbm + trace compounds And many trace compounds (VOCs, ) that depend on biomass used + trace compounds Presence of trace compounds depend on gas treatment and upgrading 7

8 French technical specifications to ensure for injection Two steps to carry out before injecting into the gas grid: Odorization process with tetrahydrothiophene (THT) Control of specifications (some examples below) Parameter Calorific Value (0 C - 1,01325 bar) Tetrahydrothiophene (odorant) Total Sulfur Mercaptans H 2 S + COS Specification 10,7 12,8 kwh/scbm (for H type gases) 9,5 10,5 kwh/scbm (for B type gases) from 15 to 40 mg/scbm < 30 mgs/scbm < 6 mgs/scbm < 5 mgs/scbm And also on : -Wobbe Index, density, water dew point and HCDP, CO 2, O 2, H 2, CO -Trace compounds: Hg, Cl, F and NH 3 Others traces compounds could have a negative impact on the gas grid (e.g. siloxanes, terpenes, ) => Focus on terpenes 8

9 What are terpenes? Large class of organic compounds : Produced by plant, conifers Chemically derived from units of isoprene Strong-smelling isoprene Found in Household cleaning products Two main risk for gas grid Impact on gas odorization: Terpenes could mask the odorant of gas Terpenes could create condensates during pressure decrease Necessity to identify and quantify terpenes in biomethane 9

10 Impact of terpenes on odorization What is the impact of terpenes on gas odorization? According to a dutch study: A content of 4 ppm of terpenes could mask the odor of gas However, there are a few data available in biomethane No olfactometry study has been carried out for now Good odorization Odorization? mg/scbm mg/scbm To study this impact, biomethane characterization should be performed for terpenes and others odoriferous compounds. 10

11 Terpenes content in biogas (litterature) Compounds Content Intrants Gas Country Cumène detected WWTP biogas UK d-limonène 0,3 mg/scbm WWTP biogas UK α-pinène 1,4 mg/scbm WWTP biogas UK β-pinène 0,3 mg/scbm WWTP biogas UK 3-carène Detected WWTP biogas UK d-limonène 84 mg/scbm Food wastes biogas UK α-pinène 5 mg/scbm Food wastes biogas UK β-pinène 8,9 mg/scbm Food wastes biogas UK 3-carène 1,7 mg/scbm Food wastes biogas UK α-pinène 0-21 ppm - biomethane NL 3-carène 0-4 ppm - biomethane NL Limonène 0-37 ppm - biomethane NL p-cymène 0-15 ppm - biomethane NL p-cymène 85 ppm Food and green houshehold wastes biogas SW Limonène 26 ppm déchets agro-alimentaires et verts biogas SW Limonène 0,26 mg/scbm - biogas FR 11

12 Scope of the study: compounds and contents To develop and characterize a sampling and analysis method for terpenes in biomethane Method development focused on 4 terpenes : α-pinène (C 10 H 16 ) β-pinène (C 10 H 16 ) d-limonène (C 10 H 14 ) p-cymène (C 10 H 16 ) Targeted contents : from µg/scbm to mg/scbm (till: 10 ppm) Data basis for risk assessment of terpenes presence on odorization 12

13 Different strategy to measure terpene content Continuously sampling Online measurement Online GC, Biomethane Offline sampling Analysis in laboratory GC-MS, GC-FID, 13

14 Different strategy to measure terpene content Scope of the study: Device assessment Continuously sampling Online measurement Online GC, Biomethane Offline sampling Analysis in laboratory GC-MS, GC-FID, 14

15 Method optimization on GC-FID Optimization of GC separation: One analysis each 5 minutes Temperature = 130 C Pressure = 60kPa : α-pinène 2: β-pinène 3: d-limonène 4: p-cymène Online GC-FID 15

16 Method characterization Caracteristics Target contents From 0,5 to 10 ppm (for each terpene) Repeatability RSD < 4 % RSD < 1% (upper than 5 ppm) Linearity Limit-Of-Quantification Assessed 0,2 ppm (each terpene) eq to 1,2 mg/scbm Analytical performences are convenient thanks to a FID detector linear, stable and sensitive BUT robustness of the device has to be improved for online measurement 16

17 Different strategy to measure terpene content Continuously sampling Online measurement Online GC, micro-gc Biomethane Scope of the study: Method development Offline sampling Analysis in laboratory GC-MS, GC-FID, 17

18 Sampling and analysis method: 4 steps to optimize Target content : µg/scbm => a preconcentration step is needed! Sampling step on sorbent tube Thermaldesorption step GC analysis method MS detector parameters Sorbent to select Sampling gas flow Gas volume Breakthrough volume Standard Gas flow for desorption Desorption temperature Temperature for compound separation Injection parameter (split, splitless,...) Simulating Ion Monitoring (SIM) Method Transfer Ligne Temperature 18

19 Peak Area (x10 5 ) RSD [%] Sorbent matrix selection: Carbotrap C tenax Carbotrap a-pinene b-pinene p-cymene d-limonene Tenax Carbotrap a-pinene b-pinene p-cymene d-limonene Peak areas are similar between tenax and carbotrap Better dispersion is obtained with carbotrap Carbotrap is the sorbent matrix selected 19

20 Thermaldesorption unit method optimization ISO (1) Sampling on adsorption tube (2) Thermaldesorption and (3) cryofocalisation in line Sampling on adsorption tube Thermaldesorption Cryofocalisation (CIS) GC-MS analysis Criteria : Blank quality Signal intensity Signal repeatability (4) GC-MS analysis 20

21 Analytical method by GC-MS based on 4 target terpenes Abundance : α-pinène 2 : β-pinène 3 : p-cymène 4 : d-limonène Time (min) Column: CP-Sil5CB - 30 m (100% polydimethylsiloxane) Oven : 40 C to C/min then C/min 21

22 Method characterization Breakthrough volume Sampling Robustness Limit of Quantification with TDS-GC-MS estimated with 14 liter of gas Compounds LOQ (µg/nm 3 ) LOQ (ppb) Repeatability GC-MS analysis Linearity Range of contents Limits Of Quantification and Detection α-pinène 15 2,5 β-pinène 20 3,3 p-cymène 12 2,0 d-limonène 16 2,6 Sample storage and conservation Storage duration Influence of temperature 22

23 Quantification test on real sample Abundance 1.2e e+07 1e Four terpenes identified in real biomethane: - α-pinène - 3-carène - p-cymène - d-limonène Time [min]

24 Summary Online GC-FID Offline TDS-GC-MS Fast Easy-to-use ++ + Sensitivity + (200 ppb) +++ (2 ppb) Robustness - + Application Continuous measurement in real time Offline measurements 24

25 Conclusion and Outlooks Different method can be used to measure terpene TDS sampling is environmental friendly, sensitive and easy to perform but GC-MS analysis requires a high-skilled technician Online GC enables continuous measurement but robustness has to be improved 2015 projection olfactometry of biomethanes Characterization of trace compounds in biomethanes produced from WWTP and household wastes (on line analysis to study time variability) Characterization of odoriferous compounds in biomethane (laboratory analysis based on GC-sniffing) Characterization of the odour of non-odorized biomethane and odorized biomethane (olfactometry analysis) This project aims at identifying : -the compounds that may interfere with biomethane odorant -and the level of concentrations that may be expected in biomethane 25

26 Etienne BASSET C. SENNE, L. PYREE, A. LOUVAT, H. RABETSIMAMANGA CRIGEN - Research and Innovation Center in Gas and Renewable Energies 361 avenue du Président Wilson Saint-Denis La Plaine - France Thank you for your attention! Any questions? 26