DATABASE llnl.dat
TITLE Kinetic decomposition of sodium acetate
definition of Methane decouples CO2 and CH4

SOLUTION_MASTER_SPECIES
    Methane Methane 0.0 CH4 16.0432
SOLUTION_SPECIES
    Methane = Methane
    log_k = 0
SOLUTION 1
    temp    200
    units   mol/kgw
    ph  7
    Na  .1
    Acetate .1
    Cl  .001    charge
KINETICS 1 Define Acetate parameters
    NaAc
#   reaction is NaCH3COO(aq)  + H+  -> Na+  + CH4(aq)  + CO2(aq)
#     or in phreeqc NaAcetate(aq) + H+  -> Na+  + Methane  + HCO3-
        -formula  Acetate -1 H -1 Methane 1 C 1  O 2
        -m    .1
        -m0   .1
        -parms    242908  7.0244e13
# these parameters give a rate constant at 200 C = 1.0734e-13.
    -steps  3.1556925e13 in 100 steps
INCREMENTAL_REACTIONS true
RATES
    NaAc
    -start
    1   rem PARM(1) is Ea
    2   rem PARM(2) is A
    10  R = 8.31451
    20  T = 473.15
    30  rate_const = PARM(2)*EXP(-PARM(1)/(R*T))
    40  rate = rate_const*TOT("Acetate")
    50  moles = rate*TIME
    60  PUT(rate,1)
    200 SAVE moles
    -end
SELECTED_OUTPUT
    -file   acetate.sel
    -reset  false
USER_PUNCH
    -headings    Time(yrs) rate  Acetate C(4) Methane
    -start
    10  PUNCH  TOTAL_TIME/31556925 GET(1) TOT("Acetate") TOT("C(4)") TOT("Methane")
    -end
END