Nitrosamine Formation in Amine Scrubbing Nathan A. Fine Texas - PowerPoint PPT Presentation

Nitrosamine Formation in Amine Scrubbing Nathan A. Fine Texas Carbon Management Program University of Texas at Austin Department of Chemical Engineering September 18, 2013 1

Outline  Motivation  Carcinogenicity  Nitrosamine Cycle  Current Work  NO 2 absorption  Nitrosation from nitrite  Nitrosamine accumulation 2

Motivation Maximize environmental benefit of amine scrubbing 3

Nitrosamine Carcinogenicity  React in target organs to form diazonium-carbocation intermediates  Leads to DNA alkylation and tumor growth  Over 80% are carcinogenic Inami et. al 2009 4

Nitrosamine Cycle Absorb orber Stri ripper 5

Nitrosamine Formation NO 2 absorption Nitrosation from nitrite 6

NO 2 Absorption Chemistry  7

The Wetted Wall Column FTIR Vent [NO 2 ] bypass [NO 2 ] WWC NO 2 flux K g and k g ’ N 2 Solvent reservoir CO 2 5000ppm NO 2 /N 2 8

NO 2 Absorption into Water 10 Shen 1997 NO 2 Flux*10 5 (mol/s m 2 ) 1 0.1 WWC 0.01 6% NO 2 absorption For 5ppm NO 2 0.01 M NaOH, T=20 °C 0.001 0.1 1 10 100 P NO2 LM (Pa) 9

NO 2 Absorption into MEA 1 NO 2 Flux*10 5 (mol/s m 2 ) 0.1 MEA Water Absorption dominated by k’ g MEA at 5 ppm NO 2 0.01 9m MEA, α =0.38 T=40 °C 0.001 0 1 10 P NO2 LM (Pa) 10

NO 2 Absorption Into Amines 100 β =100% NO 2 k' g Am *10 5 (mol/s m 2 Pa) absorption β =98% NO 2 Unloaded absorption MDEA Loaded 8m 10 PZ Loaded 9m MEA β =65% NO 2 absorption 1 0.01 0.1 1 10 Free Alkalinity (m) 11

Nitrosation from Nitrite Absorb orber Stri ripper 12

Nitrosation of 1 ° /2 ° Amines with Nitrite k 3 100C (M -2 s -1 ) E a (kJ/mol) 1000 84 62 PZ PZ 42 (s -1 ) ME MEA 100 680 73 6 (s DE DEA 10 6 del *10 Mode MAE AE k Mo 10 1 1 10 100 1000 k Obs bs *10 10 6 6 (s (s -1 ) 13

Nitrosamine yield: 1 ° Amines  14

Dilute DEA in MEA  5% 4% NDELA Yield 3% 2% 1% DEA diluted in 9m MEA, α =0.38 T=150 °C for 3 hours 0% 0.000 0.005 0.010 0.015 0.020 [DEA]/[MEA] 15

Reactivity in 9m MEA 10 DEA Relative Reactivity (R) Experimental HEGly HEEDA 2 ° Amine diluted in 9m MEA, α =0.38 Heated at 120 °C for 24 hours 1 0 0.1 0.2 0.3 0.4 MEA Loading (Mol CO 2 /mol MEA) 16 *Carbamate and protonate stability for DEA/MEA extrapolated from 40 °C

Nitrosamine yield: 2°/3° Amine Blends  Tertiary amines do not form carbamates  Nitrosate very slowly  Yield from 2° amine nitrosation is close to unity at promoter concentrations Blend MNPZ Yield (%) 0.1-8m PZ 95 ± 11 PZ/Methyldiethanolamine (MDEA) 85 PZ/Triethanolamine (TEA) 102 PZ/Dimethylaminopropanol (DMAP) 93 PZ/Diethylaminoethanol (DEAE) 96 2m PZ / 7m 3° amine; α =0.25; Heated for 3 hours at T = 150 °C 17

Nitrosamine Accumulation Balancing NO 2 absorption and nitrosation with nitrosamine decomposition 18

Nitrosamine Accumulation 100 Nitrosamine (mM) 10 1 0.1 9m MEA, 10 mM 9m MEA, 50 mM 8m PZ, T=150 °C 7m MDEA/2m PZ HeGly, T=120 °C HeGly, T=120 °C T=135 °C 19

Nitrosamine Accumulation 100 Nitrosamine (mM) 10 1 0.1 9m MEA, 10 mM 9m MEA, 50 mM 8m PZ, T=150 °C 7m MDEA/2m PZ HeGly, T=120 °C HeGly, T=120 °C T=135 °C 20

Nitrosamine Accumulation 100 Nitrosamine (mM) 10 1 0.1 9m MEA, 10 mM 9m MEA, 50 mM 8m PZ, T=150 °C 7m MDEA/2m PZ HeGly, T=120 °C HeGly, T=120 °C T=135 °C 21

Nitrosamine Accumulation 100 Nitrosamine (mM) 10 1 0.1 9m MEA, 10 mM 9m MEA, 50 mM 8m PZ, T=150 °C 7m MDEA/2m PZ HeGly, T=120 °C HeGly, T=120 °C T=135 °C 22

Nitrosamine Accumulation 100 Nitrosamine (mM) 10 1 0.1 9m MEA, 10 mM 9m MEA, 50 mM 8m PZ, T=150 °C 7m MDEA/2m PZ HeGly, T=120 °C HeGly, T=120 °C T=135 °C 23

UTCCS-1 January 28-30, 2014 Austin, TX Open to sponsors of the Texas Carbon Management Program And to non-profit institutions with presentations Titles and abstracts due October 15, 2013 to gtr@che.utexas.edu www.GHGT.info October 5 - 9, 2014 | AUSTIN, TX - USA

Thermal Cylinder Experiments  Solution Preparation  0.1-8m amine, α =0.1-0.4  50 mmol/kg NaNO 2  Batch Experiment  Loaded in \ inch Swagelok thermal cylinders  Convection oven at 80-150°C  Quenched in water bath at 21 °C  Stored in amber vials and analyzed within a week  Pseudo-first order observed rate determined from nitrite disappearance 25

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