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# Control Model For Rotary Kilns

IP.com Disclosure Number: IPCOM000096735D
Original Publication Date: 1963-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 51K

IBM

## Related People

Sandelien, JF: AUTHOR

## Abstract

A prerequisite to computer control of a rotary kiln is a mathematical model defining the relationship which exists between the input and output variables. Input variables fall generally into two classes. The first includes the fuel air flow, feed flow, and kiln speed, known as manipulated variables. The second category is that of disturbance variables which are measurable but cannot be controlled by computer action. This class includes variations in feed, composition, moisture content, in fuel quantity and in temperature surrounding the kiln. In addition, there are variables falling in the second category which are individually measurable such as secondary air temperature and bed depth at predetermined points along the kiln.

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Control Model For Rotary Kilns

A prerequisite to computer control of a rotary kiln is a mathematical model defining the relationship which exists between the input and output variables. Input variables fall generally into two classes. The first includes the fuel air flow, feed flow, and kiln speed, known as manipulated variables. The second category is that of disturbance variables which are measurable but cannot be controlled by computer action. This class includes variations in feed, composition, moisture content, in fuel quantity and in temperature surrounding the kiln. In addition, there are variables falling in the second category which are individually measurable such as secondary air temperature and bed depth at predetermined points along the kiln.

The output variables are those indicative of the process performance and the control objective such as temperature points along the kiln. The output variables are related to the input variables by the mathematical model structure shown. The relationship consists of a set of linear lumped parameter differential equations which is represented by the equivalent LaPlace transforms G(1)... G(22).

Disturbance variables D(1), D(2) and D(3) allow correction for errors due to inaccuracies in the model. These variables are determined by using past and present values of the manipulated variables and the known disturbance variables.

After the input variables are measured and placed in the computer, the output variables are...