Optical cells with fused silica windows for the study of geological fluids

I-Ming Chou

U.S. Geological SurveyReston, Virginia

USA

Outline• HDAC vs FSCC• Two types of optical cells with fused silica windows for

the study of geologic fluids (C-O-H-N-S-salts) at P-T conditions up to 100 MPa and 600 ºC:– (1) High pressure optical cell ( HPOC) for samples

with known compositions and adjustable pressures for in-situ experiments

– (2) Fused silica capillary capsule (FSCC) for samples with mostly uncertain composition and pressure, and suitable for long term (days or weeks) experiments

• Constructions of these optical cells and applications• Summary

April 17, 2005At APS

Argonne National Lab

Bassett et al. (1993)

HDAC type V

Kenji MibeEarthquake Research Institute

University of Tokyo, Japan

Raman study of synthetic subduction-zone fluids

(KAlSi3O8-H2O) system

SCF: supercritical fluidF: aqueous fluidSa: sanidineM: hydrous meltMs: muscoviteC: corundum

Dec. 6, 2006at USGS

Mibe, Chou, & BassettJGR, 113 (2008)

SanidineKAlSi3O8

MuscoviteKAl2(Si3Al)O10(OH)2

Some mineralsin the system:

KAlSi3O8 - H2O

CorundumAl2O3

Mibe, Chou, & BassettJGR, 113 (2008)

Mibe, Chou, & BassettJGR, 113 (2008)

Moleculea Frequency (cm-1)b Motionj

H4SiO4 (Mo) 783 (calc)c, 785 (exp)d, 788 (calc)e n(Si-O)

KH3SiO4 (Mo) 748 (calc)f n(Si-O)

H6Si2O7 (D) 620 (calc)e, 631 (calc)c, 638 (calc)g n(Si-O), d(Si-O-Si)

H6SiAlO71- (D) 585 (calc)g n(Tk-O), d(Si-O-Al)

H4SiAlO73- (D) 574 (exp)d n(T-O), d(Si-O-Al)

H6Si3O9 (3R) 629 (calc)e n(Si-O-Si)H6Si2AlO9

1- (3R) 574 (calc)h n(T-O-T)H8Si4O12 (4R) 490 (calc)h n(Si-O-Si)

H8Si3AlO121- (4R) 488 (calc)h n(T-O-T)

Al(OH)41- 616 (calc)i, 620 (exp)d n(Al-O)

KAl(OH)4 619 (calc)f n(Al-O)KH2AlO3 691 (calc)f n(Al-O)Al(OH)3H2O 438 (calc)i n(Al-OH2)

KOH 361 (calc)f d(K-O-H)

Mibe, Chou, & Bassett

JGR, 113 (2008)

Jan. 16, 2008at USGS

Wanjun LuChina Univ. of Geosci.

Zhiyan PanZhejiang Univ.

of Tech. Xiaochun XuHefei Univ.

of Tech.

Synthetic Fluid Inclusionsin Quartz

(Sterner & Bodnar, 1984)

• Pre-fractured quartz core or prism, together with sample fluid and silica powder, were sealed in a precious-metal capsule.

• The fractures in quartz were healed at a fixed P-T condition in a pressure vessel and captured sample fluid as inclusions.

• To heal the fractures requires high T (> 300 ºC) and time (days and weeks).

Lin (2005)

• Synthesized CH4-H2O fluid inclusions in quartz in Pt capsules at 300 to 700 C and 1, 3, and 5 kbars

• Al4C3 +12 H2O = 3 CH4 + 4 Al(OH)3

• All inclusions formed at and above 600 C contain CO2

CH4+ H2O = CO2 + H2

Polymicro Technologies, LLC(www.polymicro.com).

Fused Silica Capillary Tube

Square-sectioned tubeRound-sectioned tube

HPOCChou et al. (2005)

GlandSleeve

Valve Fused silicaHP tube

Chou, Burruss, Lu (2005)Chapter 24 in

Advances in High-Pressure Technologyfor Geophysical Applications

Raman Spectra for CH4 in Different Phases

2911

.3

Dissolved CH4(31.7 MPa)

Gas phase @ 3.4 MPa2917.3 cm-1

2880 2890 2900 2910 2920 2930 2940Wavenumbers (cm-1)

Inte

nsit

y (a

.u.)

Large cage Small cage

2904.8 cm-1

2915 cm-1

CH4 sI Hydrate

P (MPa)0 20 40 60 80

-8

-6

-4

-2

0

D =

n -

n o (cm

-1)

P (MPa)0 20 40 60 80

CH

4 1 p

eak

posi

tion

(cm

-1)

2910

2912

2914

2916

2918

Thieu et al. (2000)

Hansen et al. (2001)

Thieu (1998)

Seitz et al. (1996)Fabre & Couty (1986)

Hester (2002)

Jager (1998)

Lin (2005) This study

Lu, Chou, Burruss, Song GCA (2007)

no = p.p. near 0 Pn = p.p. at high P

P (MPa) = - 0.0148 D5 - 0.1791 D4

- 0.8479 D3 - 1.765 D2 - 5.876 D

What Are Gas Hydrates ?

136 H2O

46 H2O

34 H2O

2

16

3

6

8

2 1

51264

51268

51262

512

435663

Structure I

Structure II

Structure H

Methane, Ethane, Carbon dioxide, etc.

Cavity Types Hydrate Structure ‘Guest’ Molecules

Propane, Iso-butane, etc.

Methane + Neohexane,Methane + Cycloheptane,

etc.

Chou et al. (2000) PNAS, v. 97, 13484-13487

SH

SII

SI G

35.3 C137 MPa

[X(CH4)] = 1.0563 [A(CH4)aq/A(H2O)]r2 = 0.9962

Lu, Chou, Burruss, Yang (2006)Applied Spectroscopy

115 minutes after being pressurized by CH4 at 24.47 MPa

Y = 0.70 mm

Y = 4.12 mm

[X(CH4)] = 1.0563 [A(CH4)aq/A(H2O)]

Ymax. = 12.2 mm

Diffusion of Methane in Water

D = 1.66 x 10–9 m2s-1Lu, Chou, Burruss, & Yang (J. Applied Spectroscopy; 2006)

Keith Kvenvolden

Davie et al. (2004)

This studyLu, Chou, Burruss

GCA (2008)

Yang et al. (2001)

Servio & Englezos (2002)

Kim et al. (2003)

Previous studies

CH4 conc. in equilib. with

methane hydrate

Lu, Chou, & Burruss(GCA, 2008)

Growth of methane hydrate in 2 wt% Na2SO4 aqueous solution

near room temperature

T dropped from ~23oC to ~22oC in one hour

CH4 tank

Vacuum line

Immersed in liquid N2

Sample loading systemfor a capillary capsule

~ 11 mm

Methane Hydrate

Smackover Oil(50 μm ID)

Room T(50 μm ID)

H2O CO2 (L) CO2 (V)CO2-H2O

m

Methane hydrateat 22oC

~ 40 MPa

Chou, Song, Burruss (GCA, 2008)

Cracking of octadecane (C18H38) with various densities at 350, 375, and 400

Methane

Ethane

Propane + n-butane

350 C

Duration (hrs)

Peak

Are

a Fr

actio

n

• Our understanding of the reaction pathways and decomposition of organic compounds in the

presence of water is limited. • Raman spectroscopic analysis for the following

reactions at 206 °C for 41 hours:

– CH4 + H2O = CH3OH + H2

– C2H6 + H2O = C2H5OH + H2

– C2H6 + 2 H2O = CH3CO2H + 3 H2

Shang et al. (GCA, 2009)

(1963)(1941)

r2 = 0.99991

Modified from: Williamson & Rimstidt (1992)

Number of Sulfur AtomsAv

erag

e Fo

rmal

Cha

rge

on S

ulfu

r -2

+1

-1

+4

+2

0

+3

+5

+6

+7

1 32 4 765

S2-

S22-

S2O32-

S32-

S52-S4

2-S6

2- S72-

S3O32-

S4O32- S5O3

2- S6O32- S7O3

2-

SO42-

S2O42-

SO32-

S2O62-

S2O72-

S2O82-

S3O62-

S4O62-

S5O62-

S2O52-

S6O62- S7O6

2-

S8

8

TSR by H2

300 oC107 MPa10 days

300 oC (v)

In-situ Ramanin USGS heating stage

TSR by CH4

In-situ Ramanin USGS heating stage TSR by CH4

Stretching frenquency of water dissolved in CO2

at 32 ºCas a function of

CO2 density

Berkesi et al.(2009)

Uranyl chloride complexes in LiCl solution (1.5 molal) at 200 ºC at vapor satrated (Dargent et al., 2012)

C

CH3

CH3

O CO

O H2O C

CH3

CH3

HO OH CO2nn nn

Polycarbonate Bisphenol A

Hydrolysis of Polycarbonate in sub-critical water (280 oC)

Pan, Chou & Burruss (Green Chem., 2009)

0 10 20 30 40 50 600

1

2

3

4

5

0

20

40

60

80

100

Peak area

Reaction time / min

R2=0.996

Peak area

×104

Depolymerization yeild / %

Depolymerization yeild

INSTEC Heating-Cooling Stage

FSCC (0.1 mm ID)

CO2

Linkam 500Capillary Pressure Stage

7: Capillary sample holder8: Capillary movement mechanism9: Silver block heater & cover10: Pt sensor protection plate11: 16 mm glass cover slip

Linkam 500Capillary Pressure Stage

1: Qtz sample carrier for FSCC(25 mm movement)

2: Silver cover

Linkam 500Capillary Pressure Stage

Error band over 30 mm of movement

Summary

• Optical cells with fused silica windows, such as HPOC and FSCC, were designed for experiments at pressures up to 100 MPa and temperatures up to 600 ºC, such as the P-T conditions of sedimentary basins, hydrothermal systems, and low-grade metamorphism.

• These types of cells are particularly suitable for the study of organic compounds and also for the systems containing S.

Summary• When compared with the conventional synthetic fluid

inclusion method, in which fluid inclusions were formed by healing fractures in quartz chips at elevated P-T conditions, the new FSCC method has the following advantages: (1) simple; (2) large and uniform inclusions can be formed; (3) suitable for the studies of organic material and/or S with/without water, and (5) allowing redox control when needed, especially for TSR experiments.

• The HPOC & FSCC have a great potential for studying geologic fluids at various P-T conditions, as demonstrated by many examples.