Feed Block¶
Feed Blocks are used to represent sources of material in Flowsheets. These can be used to determine the full state of a material (including equilibrium) based on a sufficient set of state variables prior to being passed to the first unit operation.
Degrees of Freedom¶
The degrees of freedom of Feed blocks depends on the property package being used and the number of state variables necessary to fully define the system. Users should refer to documentation on the property package they are using.
Model Structure¶
Feed Blocks consists of a single HoldupStatic Block (named holdup), each with one Outlet Port (named outlet).
Construction Arguments¶
The Feed model has the following construction arguments:
- property_package - property package to use when constructing Property Block for the Feed Block (default = ‘use_parent_value’). This is provided as a Property Parameter Block by the Flowsheet when creating the model. If a value is not provided, the Holdup Block will try to use the default property package if one is defined.
- property_package_args - set of arguments to be passed to the Property Block when they are created.
- outlet_list - list of names to be passed to the build_outlets method (default = None).
- num_outlets - number of outlets argument to be passed to the build_outlets method (default = None).
Additionally, Feed Blocks have the following construction arguments which are passed to the Holdup Block for determining which terms to construct in the balance equations. Feed Blocks do not support dynamic = True.
Argument | Default Value |
---|---|
material_balance_type | ‘component_phase’ |
energy_balance_type | ‘total’ |
momentum_balance_type | ‘total’ |
dynamic | False (cannot be True) |
include_holdup | False |
has_rate_reactions | False |
has_equilibrium_reactions | False |
has_phase_equilibrium | False |
has_mass_transfer | False |
has_heat_transfer | False |
has_work_transfer | False |
has_pressure_change | False |
Additional Methods¶
Feed Blocks define three additional methods useful for defining and interpreting the feed conditions. These methods are documented below in the FeedData Class section;
- display()
- fix()
- unfix()
Additional Constraints¶
Feed Blocks write no additional constraints to the model.
Variables¶
Feed blocks add no additional Variables.
FeedData Class¶
-
class
idaes.models.feed.
FeedData
(component)[source]¶ Standard Feed Block Class
-
display
(display_block=False, ostream=None, prefix='')[source]¶ Display the contents of Feed unit.
Parameters: - display_block – indicates whether to display the entire Block
- object (default = False) –
- ostream – output stream (default = None)
- prefix – str to append to each line of output (default = ‘’)
Returns: None
-
fix
(var, comp=None, value=None, time=None)[source]¶ Method for fixing Vars in Feed Block.
Parameters: - var – variable name to be fixed (as str)
- comp – index of var to be fixed (if applicable, default = None)
- value – value to use when fixing var (default = None)
- time – list of time points at which to fix var (can be float, int
- list) (or) –
Returns: None
-