Command-Line Interface

sandlerchemeq provides a command-line tool for solving chemical equilibrium systems without writing Python code.

sandlerchemeq [<global-options>] <command> [<command-options>]

Global Options

-h, --help
    Show help message and exit.

-b, --banner / --no-banner
    Toggle the banner message (default: off).

--logging-level {info,debug,warning}
    Verbosity of diagnostic messages (default: debug).

-l LOG, --log LOG
    Write diagnostic log to this file.

Commands

solve

Solve a chemical equilibrium system.

sandlerchemeq solve [options]

Required options:

-T TEMPERATURE / --temperature TEMPERATURE

System temperature in Kelvin.

-P PRESSURE / --pressure PRESSURE

System pressure in bar.

-n0 N [N ...] / --initial-moles N [N ...]

Initial molar amounts for each component (same order as components).

Mutually exclusive — specify one:

-c NAME [NAME ...] / --components NAME [NAME ...]

List of component names (database names from sandlerprops). Uses the Lagrange multiplier method.

-r RXNSTR [RXNSTR ...] / --reactions RXNSTR [RXNSTR ...]

One or more reactions, each as a comma-delimited string of component names (no spaces). Components are inferred from the reaction strings. Uses the explicit reaction method.

Optional:

-xinit X [X ...] / --X-init X [X ...]

Initial guess for extents of reaction (one per reaction). Required when --reactions is used for good convergence.

Examples

Lagrange Method

No explicit reactions — just list the species and initial amounts:

sandlerchemeq solve -c "hydrogen (equilib)" nitrogen ammonia -T 400 -P 100 -n0 3. 1. 0.

Output:

N_{H2}=0.1113 y_{H2}=0.0536
N_{N2}=0.0371 y_{N2}=0.0179
N_{NH3}=1.9258 y_{NH3}=0.9285

sandlerchemeq solve -c "hydrogen (equilib)" nitrogen ammonia -T 600 -P 100 -n0 3. 1. 0.

Output:

N_{H2}=1.2110 y_{H2}=0.4314
N_{N2}=0.4037 y_{N2}=0.1438
N_{NH3}=1.1926 y_{NH3}=0.4248

Explicit Reaction Method

Specify reactions as comma-delimited component lists (reactants first, products last):

sandlerchemeq solve -r "hydrogen (equilib),nitrogen,ammonia" -T 400 -P 100 -n0 3. 1. 0. -xinit 0.95

Output:

Reaction    I:  3 H2  +  1 N2   <->   2 NH3  |  Ka(400.00 K)=3.12266e+01 => Xeq=9.62910e-01
N_{H2}=0.1113 y_{H2}=0.0536
N_{N2}=0.0371 y_{N2}=0.0179
N_{NH3}=1.9258 y_{NH3}=0.9285

Tip

Compound names containing spaces must be quoted on the command line. For reactions, names within the comma-delimited string must not contain commas. The compound name hydrogen (equilib) is the standard-state H₂ entry (ΔGf = ΔHf = 0) in the sandlerprops database.