Estimating the Vaporization Time in Batch Reactors

Edward H. Steve, P.E.

Course Outline

When material is vaporized from a batch reactor, the heat transfer area decreases and integration over the area change is needed to determine the total time required.  This three hour course starts with basic reactor geometry and develops the concepts of initial and effective heat transfer areas in a stepwise manner.  After explaining thermal considerations, the basic heat balance for using steam as the heating utility starts the step-by-step derivation of the equation needed to estimate the vaporization time.  Based on a different heat balance expression, the course then develops the equation for estimating the vaporization time for using HTF as the heating utility.  Sample calculations illustrate how the derived equations are applied to a production scale reactor.  This course enables the engineer to apply the simple derived equations at his or her desktop and offers a spreadsheet format that can be used to present the results for review and comment.

This course includes a multiple-choice quiz at the end.  The questions have been designed to provide practice in applying the derived equations for estimating vaporization times and to enhance understanding of the underlying principles.

Learning Objective

At the conclusion of this course, the student will:

• Be able to estimate the vaporization time with steam as the heating utility;
• Be able to estimate the vaporization time with HTF as the heating utility;
• Understand the area and volume characteristics of two commonly used reactor heads;
• Be able to calculate the initial and effective (at any time) heat transfer areas;
• Understand the assumptions and limitations underlying the development of the equations; and
• Understand the mathematical techniques for simplifying complex equations for easier manipulation.

Intended Audience

This course is intended for chemical and mechanical engineers who either design or operate batch reactor production facilities.

Benefit to Attendees

An attendee of this course will be able to easily and quickly estimate the time needed to complete a vaporization operation in a batch reactor cycle for both steam and HTF utilities.

Course Introduction

Often the operating cycle of an agitated jacketed batch reactor includes a step that reduces the volume of the contents by vaporization at either atmospheric or reduced pressure to concentrate a dissolved product.  Alternately it could be the first step in the replacement of one solvent with another.

This course provides the practicing process engineer with the equations needed to easily and quickly estimate the time required to remove a defined amount of liquid from a jacketed batch reactor by vaporization.  The course develops equations for both steam and heat transfer fluid (HTF) used as the heating medium.

The step-by-step derivations serve as mathematics refreshers for those who have not used this skill recently.

Before beginning his or her study, the student should become familiar with the definitions and the associated units of the items in the NOMENCLATURE list that appears at the end of the course.

Course Content

This course content is in the following PDF document:

Estimating the Vaporization Time in Batch Reactors