Species

) is automatically generated for the participating reactants and products. This feature enables you to review and enter species specific information regarding chemical kinetics, thermodynamics and transport properties.

It is also possible to add and define an individual node: on the toolbar click or right-click the node and select it from the context menu.

When a node is automatically generated using the text field for the Reaction node, the is also automatically generated.

For a node added individually, enter a in the field and click .

	Creating Valid Species Names and Labeling

Select a species type — , , or .

and are solved for volumetric concentrations (SI unit: mol/m3), while are solved for surface concentration (SI unit: mol/m2). The compositions for and use the syntax c_speciesname, while uses csurf_speciesname_surf.

Surface species is referring to species adsorbed on a reactive surface. When is selected, the corresponding reaction formula introduces after the species notation and changes the species’ name to speciesname_surf. Additionally, the Species node name is updated in a similar fashion.

For the reactor only and are allowed.

	Choosing the Species Type

The section deals with species parameters.

The default value for the , M (only shown when needed), and the ionic , z, of the species is automatically defined from the species name by assuming that it corresponds to its chemical formula. Provided that the formula contains elements from the periodic table, the species molar mass is computed from mass the of occurring individual elements¹. When the species name contains parts not in the periodic table, for example when a descriptive name such as water is used, the molar mass is set to 0.0 kg/mol and the charge to zero. In this case, the molar mass needs to be defined in order to achieve mass balanced reactions and correct definitions of mass basis properties. The species charge is also deduced from the species name. Creating a H+ species, the charge will be set to one. When needed, both the and the can be edited in the corresponding edit field.

It is possible to specify the species density ρ when the fluid is specified as . The default value is that of water at 293 K.

Change the default setting to to use a species reaction rate other than the one set up in the associated Reaction node. For individual species, use the option to set a reaction rate other than zero (that is, nonreactive).

Edit either the (SI unit: mol/(m3s)), the (SI unit: mol/(m2s)), or both. For a bulk species, both expressions appear if surface reactions are present in the reactor since the reaction of the species can depend both on bulk reaction R and surface reaction Rads rates. For a surface species, only the surface reaction rate Rads appears.

The reaction rate is not editable if the species in question participates in an equilibrium reaction and has been selected as a in Calculate Transport Properties.

To account for nonideality in the fluid mixture adjust the activity coefficient in the text field here. The section is only shown if activity instead of concentration has been chosen in the interface; that is, the check box is selected on the Reaction Engineering interface window

Click to select the check box if the species concentration or activity should be treated as constant.

Here the required parameters to compute various transport properties can be edited. To show this section the check box needs to be selected under the section.

ε/kb (SI unit: K) the potential energy minimum value of the of the Lennard-Jones/Stockmayer potential, divided by Boltzmann’s constant. Tabulated data in literature frequently lists values of ε/kb rather than ε

ki, the thermal conductivity of the gas (SI unit: W/(m K)); and Diffusivity of the species (SI unit: m2/s). The latter two can be set to , when σ and ε/kb have been given.

The parameters utilized for calculation of thermodynamic mixture and reaction properties are set in this section. It is accessed when the Energy Balance is set to for the Reaction Engineering interface, in other words for nonisothermal conditions.

The are by default computed using data in the . In this case, enter the following to compute the species’ heat capacity, Cp (SI unit: J/(mol⋅K)), the molar enthalpy, h (SI unit: J/mol), and the molar entropy, s (SI unit: J/(mol⋅K)):

Any coefficients for the thermodynamic polynomials entered into the alow,k fields apply to the temperatures in the range Tlo to Tmid; coefficients entered into the ahi,k fields apply to temperatures in the range Tmid to Thi range. The coefficients can also be imported in the section in the Reaction Engineering node.