Keywords and settings

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Settings block

Mkmcxx 2 2 1.png

The list below is an overview of all the keywords that can be placed inside the &settings block. All keywords have a default value, so if these are not specified within the block, then the default value is used.

List of keywords and their meaning
Keyword Explanation Default value
DEBUG Output additional debug statements 0
PRESSURE The total pressure in the gas phase. If the value if negative, calculate the total pressure from the sum of the starting pressure of the compounds. -1
PRECISION Amount of significant digits to use in output. 10
USETIMESTAMP Whether to place the output in a new folder which name is based on the current time stamp. If 0, then all output is placed inside a 'RUN' folder. 1
ORDERS Whether to calculate the reaction orders. (You need to set KEYCOMPONENTS for this) 1
EACT Whether to calculate the apparent activation energy. (You need to set KEYCOMPONENTS for this) 1
DRC Whether to perform a degree of rate control analysis. (You need to set KEYCOMPONENTS for this) 1
TDRC Whether to perform a thermodynamic degree of rate control analysis. (You need to set KEYCOMPONENTS for this) 1
REAGENTS List of reagents for which the reaction orders will be calculated NULL
KEYCOMPONENTS List of compounds on which the reaction orders, apparent activation energy, DRC, DSC and/or TDRC analysis should be based NULL
GNUPLOT Whether to output GNUPlot-style graphs 0
MAKEPLOTS Whether to create plots 1
ORDERSDIFF Step size used in the linear fitting of reaction orders 0.2 (Wide: 0.4; Normal: 0.2; Tight: 0.002)
EACTDIFF Step size used in the linear fitting of the apparent activation energy 0.002 (Wide: 0.02; Normal: 0.002; Tight: 0.00002)
DRCDIFF Step size used in the linear fitting for the degree of rate control analysis 0.002 (Wide: 0.02; Normal: 0.002; Tight: 0.00002)
TDRCDIFF Step size used in the linear fitting for the degree of rate control analysis 0.002 (Wide: 0.02; Normal: 0.002; Tight: 0.00002)
BOOSTER Default multiplier used to speed-up reaction rates; sometimes leads to faster convergence towards the steady-state solution 1.0
SOLVERTYPE Type of integration method to use for solving the system of ordinary differential equations 1.0 (BDF)
SOLSTOPTIME Specificies when the solver should re-evaluate the Jacobian matrix. A value of 1 means at every time step. 1.0
SOLMAXSTEP Maximum number of internal steps the solver is allowed to take. 5000
SOLTESTFAIL Maximum number of test failures before the solver gives up 70
SOLCONVFAIL Maximum number of convergence failures before the solver gives up 100

Graphs block

Mkmcxx 2 3 0.png

Inside the graphs block, you can set the colors used in the non-GNUPLOT graphs for specific components. On each line, you place the compound between curly brackets followed by the RGB color code. For example:

&graphs
# fix colors for particular compounds
{A*} #E74C3D
{B*} #F29C1F
{C*} #287FB9
{*}  #15A086

Selectivity block

Mkmcxx 2 3 0.png

Inside the selectivity block, you can specify mole balances on which basis you calculate selectivity and degree of selectivity control graphs. You need to specify a name, a key component and one or more products (typically more than one, else the concept of selectivity is rather trivial). The name will be used in the generation of the corresponding graph file, so please use a safe name (i.e. no spaces and no special characters!)

&selectivity
species_balance; {A}; {E},{F}

In the above example, the name of the mole balance block is "species_balance", the key component is A and the products of interest are E and F. A detailed example on how to use this block is explained here.

Stoichiometry

Often, the stoichiometry of the key component and the products is not simply a 1:1 ratio. To account for this difference, you need to put the stoichiometric coefficient in front the compound. The stoichiometric coefficient is simply the number of key components which need to be consumed to produce one product. To illustrate this, below an example for CO hydrogenation towards C1-C3 hydrocarbons is provided.

&selectivity
carbon_balance; {CO}; {CH4}, 2{CH2CH2}, 2{CH3CH3}, 3{CH3CH2CH3}, 3{CH2CHCH3}