Hydrogen Interactions

[Seymensch]

Good morning fellow intellectuals

I am working as regards H2 storage and injection and I need some clarification.
1. Will the injected hydrogen be included in the GAS PHASE or the EQUILIBRIUM PHASE?
2. The hydrogen will be denoted by H2 or Hdg?
3. When working with the pressures, how best does one divide the partial Pressures If CH4 will be added as a cushion gas?

[dlparkhurst]

1. Use GAS_PHASE if you want a finite bubble in equilibrium with the formation water. For a fixed_pressure gas phase the volume of the gas phase will increase or decrease, and the gas phase may disappear. For a fixed_volume gas phase, the volume is constant, but the pressure will vary.

Use EQUILIBRIUM_PHASES if you want a constant partial pressure of hydrogen.

2. If you use H2, the H2 will react immediately with any electron acceptors available, including CO3 and SO4. If you use Hdg, no redox reactions will occur. Look at the discussions in the forum to consider kinetic reactions from Hdg to H2.

3. I don't know. A GAS_PHASE will automatically determine equilibrium partial pressures. EQUILIBRIUM_PHASES will fix the partial pressures at whatever values you specify.

[Seymensch]

Code: [Select]

REACTION_TEMPERATURE 1
    90  95  100  105  110  115  120
GAS_PHASE 1
    -fixed_pressure
    -pressure 294
    -volume 1
    -temperature 100
    CH4(g)    0
    H2(g)     0
EQUILIBRIUM_PHASES 1
    Calcite   0 0.1
    H2(g)     0 100
    Illite    0 0.4
    K-feldspar 0 0.4
    K-mica    0 0.4
    Kaolinite 0 0.5
    Quartz    0 8.1
    Siderite  0 0.1
    CH4(g)    0 10
REACTION_PRESSURE 1
    294  389.5
SOLUTION 1
    temp      100
    pH        8
    pe        4
    redox     pe
    units     ppm
    density   1
    Ca        561.12
    Cl        18761.21
    K         135.67
    Mg        1117.8
    Na        10772
    S(6)      2000
    -water    1 # kg
USER_GRAPH 1
    -headings               Pressure H2
    -axis_titles            "Pressure, atm" "H2(aq)" "Temperature"
    -chart_title            "Hydrogen in Water as a Function of Pressure"
    -initial_solutions      true
    -connect_simulations    true
    -plot_concentration_vs  x
  -start
10 GRAPH_X PRESSURE
20 GRAPH_Y MOL("H2")
30 GRAPH_SY TEMPERATURE
  -end
    -active                 true



The temperature is calibrated in -1.0 to 1.0 instead of 90 to 120 on the graph output and also the H2 loss in moles in the output file does not have any similarity with the graph output? What is the cause for this non-coherence?

[dlparkhurst]

The Basic functions for temperature are TC and TK. See The Basic Interpreter in the manual.

When you define 7 increments for temperature and 2 increments for pressure, the second pressure will be used for the last 6 reactions.

The initial solution is plotted, and has a pressure of 1 atm and no H2.

[Seymensch]

Thanks for the correction, Dr. David.

 I noticed a discrepancy in my simulations - which shows that the H2 loss in moles was the same across the different pressures and temperatures.

Code: [Select]

REACTION_TEMPERATURE 1
    90  95  100  105  110  115  120
GAS_PHASE 1
    -fixed_pressure
    -pressure 389.5
    -volume 1
    -temperature 100
    CH4(g)    0
    H2(g)     0
EQUILIBRIUM_PHASES 1
    Calcite   0 0.1
    H2(g)     0 100
    Illite    0 0.4
    K-feldspar 0 0.4
    K-mica    0 0.4
    Kaolinite 0 0.5
    Quartz    0 8.1
    Siderite  0 0.1
    CH4(g)    0 10
REACTION_PRESSURE 1
    389.5
SOLUTION 1
    temp      100
    pH        8
    pe        4
    redox     pe
    units     ppm
    density   1
    Ca        561.12
    Cl        18761.21
    K         135.67
    Mg        1117.8
    Na        10772
    S(6)      2000
    -water    1 # kg
USER_GRAPH 1
    -headings               Pressure H2 Temperature
    -axis_titles            "Pressure, atm" "H2(aq)" "Temperature"
    -chart_title            "Hydrogen in Water as a Function of Pressure-Temperature"
    -initial_solutions      false
    -connect_simulations    true
    -plot_concentration_vs  x
  -start
10 GRAPH_X PRESSURE
20 GRAPH_Y MOL("H2")
30 GRAPH_SY TC
  -end
    -active                 true


Code: [Select]

REACTION_TEMPERATURE 1
    90  95  100  105  110  115  120
GAS_PHASE 1
    -fixed_pressure
    -pressure 294
    -volume 1
    -temperature 100
    CH4(g)    0
    H2(g)     0
EQUILIBRIUM_PHASES 1
    Calcite   0 0.1
    H2(g)     0 100
    Illite    0 0.4
    K-feldspar 0 0.4
    K-mica    0 0.4
    Kaolinite 0 0.5
    Quartz    0 8.1
    Siderite  0 0.1
    CH4(g)    0 10
REACTION_PRESSURE 1
    294
SOLUTION 1
    temp      100
    pH        8
    pe        4
    redox     pe
    units     ppm
    density   1
    Ca        561.12
    Cl        18761.21
    K         135.67
    Mg        1117.8
    Na        10772
    S(6)      2000
    -water    1 # kg
USER_GRAPH 1
    -headings               Pressure H2 Temperature
    -axis_titles            "Pressure, atm" "H2(aq)" "Temperature"
    -chart_title            "Hydrogen in Water as a Function of Pressure-Temperature"
    -initial_solutions      false
    -connect_simulations    true
    -plot_concentration_vs  x
  -start
10 GRAPH_X PRESSURE
20 GRAPH_Y MOL("H2")
30 GRAPH_SY TC
  -end
    -active                 true

These are the different codes in which the only difference is pressures and the losses are still the same. What is the cause for this?

[dlparkhurst]

2. If you use H2, the H2 will react immediately with any electron acceptors available, including CO3 and SO4. If you use Hdg, no redox reactions will occur. Look at the discussions in the forum to consider kinetic reactions from Hdg to H2.