Department of process engineering U218

Computer programs for RTD analysis

R.Zitny, J.Thyn

IAEA, Vienna, 1996

RTD 0 - data treatment (corrections)

RTD 1 - nonparametrical analysis

RTD 2 - parametrical analysis, simulation, regression

models

FOREWORD

Since its introduction into chemical engineering by Danckwerts in 1953 the concept of Residence Time Distribution (RTD) has become an important tool for the analysis of industrial units. In spite of its "old age" it is still the subject of many publications in most important journals of chemical engineering concerning general or practical aspects of RTDs. Radiotracers are widely used to analyze the operation of industrial units, to eliminate troubles and to improve the economic performance of processes. The radiotracer applications cover a wide range of industrial activities in the fields of chemical and metallurgical processes, water treatment, mineral processing, environmental protection and civil engineering.

The UNDP/RCA/IAEA Regional Project for Asia and Pacific RAS/92/073 has placed a strong emphasis on the development and applications of Tracer Technology. The RTD software manual for data analysis of radiotracer experiments is the output of activities undertaken in the context of this project. Tracer experiment design, data acqusition, treatment and interpretation, are the basic elements of tracer methology. Important progress has been made during recent years in the preparation of software programmes for data treatment and interpretation. The application of radiotracers for determination of impulse response as RTD as well as technical conditions for realization of experiments in industry and environment create special request for data processing by help of special software. The software package developed for the industrial analysis and diagnostic by the stimulus reponse methods with radiotracer contains all the methods for the data processing in so called black or gray systems.

This manual is a substantial document which is to be used for the IAEA support of the Tracer Technology promoting in all Tracer Groups created in IAEA Member States. The manual is likely to be of wider interst for further development of skills and confidence prior to carrying out field work. The prepared soft is of large use in experiment designand data analysis for almost all dynamic process in industry, hydrology and environment. This manual is the suitable handbook for tracer activities in almost all field of applications. The case studies described in the manual are dealing with the typical problems of the industry and environment, common for all countries. This manual is written in professional way. Its readerships should be the engineers and technicians of tracer groups or enduser specialists working in partnerships with the tracer groups. It is expected that the information provided will be a useful guide to scientists involved in development and routine applications of nuclear techniques in diagnosis and analyze of process. The manual is an original contribution of Dr. R. Zitny and Dr.J. Thyn, Czech Technical Univer- sity, Prague. The gramatical revision was done by Dr.B.Barry, Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand. The IAEA wishes to thank all the scientists who contributed to the success of the RAS/92/073 project, especially Dr. Zitny and Dr. Thyn for the preparation of the software manual.

Dr. I. Thereska, Industrial Applications and Chemistry Section, IAEA, Vienna

Content:

1. Introduction (basic principles and applications of RTD)

2. Basic notions (RTD characteristics, moments, convolution)

3. RTD programs

3.1 General concept
3.1.1 Data structures
3.1.2 Data editor
3.1.3 Operations
3.1.4 Graphics
3.2 RTD0 data treatment (corrections)
3.2.1 Theoretical fundamentals (time decay correction, time constant correction, background raise elimination, z-transformation for variable flow)
3.2.2 Operations
3.3 RTD1 identification, recycle analysis, Fourier and Laguerre transformations
3.3.1 Theoretical fundamentals (convolution, deconvolution, recycle, frequency analysis, correlation)
3.3.2 Operations
3.4 RTD2 modelling by means of differential equation system (system identification by means of regression analysis)
3.4.1 Theoretical fundamentals (numerical integration - Euler and Runge Kutta methods and nonlinear regression)
3.4.2 Operations

4. Tasks

4.1 RTD0
-T01 introduction to RTD0, import of data, corrections, variable flow
4.2 RTD1
-T11 introduction to RTD1, import of data, interactive processing of time curves, computation of moments
-T12 impulse responses identification using splines, Fourier and Laguerre transformations
-T13 identification of a system with recycle
4.3 RTD2
-T21 introduction to RTD2, response of a system with plug flow region in the recycle stream
-T22 identification in real time domain
-T23 simulation of adiabatic reactor; time courses of temperatures and concentrations

5. List of symbols

6. References Appendices:

A1. Catalogue of RTD models
- A-simple two units models
- B-series
- C-backmixing
- D-parallel series
- E-recycles
- F-special models
- G-axial dispersions
- H-convective models
A2. List and description of input / output variables (used in journal, labels, input panels)149
A3. Applications of RTD programs
- A3.1 Steam velocity measurement - calibration of a Venturi meter
- A3.2 Production of ethylalcohol
- A3.3 Glass industry
- A3.4 Equalization of variations of impurities in waste water treatment
- A3.5 Analysis of gas flow in pressurized fluidized bed combustor
- A3.6 Production of aldehydes
- A3.7 Process of crushing and screening in a hammer mill
- A3.8 Biological activation process - waste water treatment

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