Batch Reactor Unit Operation - Technical Information
The Batch Reactor unit operation is a non-steady state unit operation which simulates the operation of a batch or semi-batch reactor.
The reaction stoichiometry must be defined in the Reaction Data Sets Window before the reactor performance can be specified. Kinetic data may be entered in the reaction set or in the reactor unit operation. Data entered in the unit operation overrides data entered in the reaction set for that unit only.
Calculation Method
The batch reactor rate of a reaction is normally calculated by the Power Law Rate Equation:
For example, in the reaction: 
then,
where 
, etc. are the activities of components A, B etc.
Activity may be expressed through Activity Coefficients or a Molar Concentration.
Alternatively, the rate of reaction may be defined through a User Added Kinetic Subroutine or an In-Line Procedure.
When only library components are present, heat of reaction is normally calculated by PRO/II from heat of formation data. Alternatively, heat of reaction data may be supplied in the Reaction Data - Heat of Reaction Data Window. If non-library components take part in a reaction, either heat of formation or heat of reaction data must be entered.
Operating Policy
The overall operating policy of a Batch Reactor is defined by one or more policy segments. Each segment has a starting condition.
Each policy segment has one or more actions. All actions in a segment start when the segment starts. Each action has an ending condition. A policy segment ends when all of its actions have reached ending conditions.
Segments may occur sequentially or may overlap in time.
The batch cycle ends when the last of its policy segments ends or when no policy segment is active or when a global end condition is met. This global end condition over-rides any ending conditions set up by the policy actions.
Feeds and Products
Feed and product streams are added as part of the PFD flowsheet construction. At least one feed and one product stream are required for the Batch Reactor. The interface between this transient unit operation and the main steady-state flowsheet is handled through a holding tank concept. Each feed stream comes from a holding tank and the bulk product goes into a holding tank. When the batch cycle has completed equilibrium calculations are carried out on the contents of the product holding tank.
