Air quality modelling studies for thermal power plants in some parts of india.

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AIR QUALITY MODELLING STUDIES FOR THERMAL POWER PLANTS IN SOME PARTS

OF INDIA

SIDHARTHA

Centre for Atmospheric Sciences

Submitted in fulfilment ofthe requirements of the degree of Doctor of Philosophy

to the

Indian Institute of Technology, Delhi

December, 2004

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CERTIFICATE

This is to certify that the thesis entitled "AIR QUALITY MODELLING STUDIES FOR THERMAL POWER PLANTS IN SOME PARTS OF INDIA" being submitted by Mr. Sidhartha to the Indian Institute of Technology, Delhi for the award of the degree of DOCTOR OF PHILOSOPHY, is a record of the original bonaffide research carried out by him.

Mr. Sidhartha has worked under our guidance and supervision and has fuiffilled the requirements for the submission ofthis thesis. The results presented in this thesis have not been submitted in part or full to any other University or Institute for award ofany degree or diploma.

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r. (Mrs.) Pramila Goyal) Principal Scientiffic Offficer Centre for Atmospheric Sciences, Indian Institute of Technology, New Delhi

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r. B. Sengupta) Member Secretary

Central Pollution Control Board, Parivesh Bhawan,

East Arjun Nagar, Delhi

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ACKNOWLEDGEMENTS

I wish to express my deepest sense of gratitude to my supervisor Dr. (Mrs.) Pramila Goyal for her valuable guidance, ceaseless encouragement, fruitful discussions, helpful ideas, moral and emotional support throughout the tenure of this work. I am extremely thankful to her for the untiring efforts and immense care in going through the manuscript.

I wish to express my deepest sense of gratitude and thanks to Dr. B. Sengupta my supervisor for his guidance, constant support and encouragement throughout my work.

My sincere thanks are due to Prof. Mathili Sharan, Head, Centre for Atmospheric Sciences for making available the necessary facilities in the Centre. I am also thankful to al!

faculty members of Centre for Atmospheric Sciences for the encouragement by them throughout this period.

I would also like to thank Shri B. Mukhopadhyay and Dr. Shiv Dcv Attri, India Meteorological Department, New Delhi for their guidance and motivation in preparation of the thesis.

At this happy moment, I fondly remember all my seniors and colleagues at C.A.S, especially Dimri, Sudhanshu, Aditi, Manish, Sankaip, Neeru, Rashmi, Sushil, Jagbandhu, Lauit, Manoj, Sangeet, Dey and many others. I can never forget the lively moments, I spent with my ffliends at hostel during my stay.

My whole-hearted indebtness will ever remain for all the help, patience and support provided by my parents all through the course of this study. My loving cheers to the kids Rimzim and Munmun.

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(SIDHARTHA)

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ABSTR.ACT

A short term Gaussian poini source model namely IIT Point Term(IITPS)model has been designed for low as well as moderate wlnd conditions _輔 th appropriate dispersion parameters and souxce inventory for predicting the concentration of chemically reactive as well as non-reactive pollutants under different meteorological conditions at different doNvnwinddislances.

A study of four different methods for estimation of dispersion parameters under various stability and wind conditions has been undertaken to find out the dispersion parameter formulation suitable for low winds under convective conditions. A comparative study of three different methods,developed by Smith(1990),Deardorff (1984)and Smith and Goyal(1995)respectively,has been made to evaluate the performance of IITPS model in calm winds conditions.

The phenomena of dry deposition,wet deposition,stack tip downwash and building downwash has been included in the IITPS Model. The effect of variation of deposition velocities on the ground level concentration in source depletion model has also been studied and it has been found that the increase in dry deposition velocity reduces the extent of human exposure and the location at which peak concentration occurs moves closer to the source. The chemical reaction terms for 502 have also been illtroduced iflto the model and sensitivity of model predictions has been tested against different downwind distances. It has been observed that the efl _セ ct of chemical reactions was negligible on the concentrations ofair pollutants uP to 10 km from the source.

Finally,the IITPS model,after including low winds,downwash and deposition

phenomena,has been validated against observed data of Dadri Thermal Power Station.

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The IITPS model's performance has also been compared with UK ADMS model (ADMS

1.3, 1995). As far as the air quality assessment of power plants is concerned, fly ash is

also an important parameter, to be included in the study. Therefore, a case study of ash

dumps of BTPS has been made. The concentration of each grid of ash dump area has

been estimated by using area source model. The analysis of model predictions has shown

that the predicted concentrations were within a factor of two of the observed values,

which indicates that model is performing satisfactorily.

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Chapter 1 1 2

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2.3.1 2.3.2 2.3.3 2.3.3.1 2.3.3.2 2.3.4 2.3.4.1

C ONTENTS

Abstract List of Figures List of Tables List of Notations

Page No.

General Introduction (1

一

25)

General Features ofAtmospheric Dispersion 2

Atmospheric Dispersion Models 4

Classiffication of Air Quality Models 5

Gaussian Models 8

Pollutant Sources And Emissions 12

Scales ofAtmospheric Dispersion 14

Air Pollution Meteorology 15

Meteorological Data 15

Mixing Height 17

Indian Meteorological Conditions 18 Planetary Boundary Layer (PBL) Parameters 18

Model Calibration 22

Organization of Thesis 22

IIT Point Source Model (26

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Introduction 26

The TIT Point Source (IITPS) Model 27 Salient Features ofThe IITPS Model 27 Selection of Study Area in the Present Study 31

Source Data 31

Air Pollution Monitoring 32

Monitoring Network Description 32

Measuring Procedure 33

Evaluation ofIITPS Model 33

Results and Discussions 33

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2.4

3.3.1 3.3.2 3.3.3 3.3.4 3.4

3.5

3.5.1 3.5.2 3.5.3 3.6

3.6.1 3.6.2 3.6.3 3.7

Chapter 4 4.1 4.2

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4.2.1 4.2.2

4.3.1 4.3.1.1 4.3.1.2 4.3.2 4.3.3 Chapter 3

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Conclusions 35

Study ofDispersion Parameters and Dispersion under (43

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77) Low Wind Conditions

Introduction 43

Diffusion Classiffication 45

Dispersion Parameters 46

Smith Formulation 47

Pasquill-Gifford curves 47

Brigg's Formulation 50

Dispersion Parameters of UK ADMS 51 Improvement ofIITPS Model for Treating Calm Winds 54 Comparison of Dispersion Parameters 59

Dataused 59

Methodology 60

Results and Discussions 64

Evaluation ofthe Models for Treating Calm Winds 66 Selection of Study Area for Evaluation ofthe Modiffied 66 IITPS Model

Results and Discussion 68

Conclusions 69

Study of Downwash and Removal Processes on (78

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101) Dispersion ofAirborne Pollutant

Introduction 78

The lIT Point Source Model (IITPS) 80 Method for Estimation of Stack Tip Downwash - 81

Estimation of Building Downwash 82

Methods for Estimation ofDeposition 87

Dry Deposition 87

Source Depletion Model 87

Surface Depletion Model 89

Wet Deposition 90

Chem ical Removal 91

Penetration ofAtmospheric Inversion by Wind-Blown, 91 Buoyancy-Driven Plumes

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Chapter 5

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4.6

Evaluation of Model Options Results and Discussions Conclusions

5.3

5.4

5.5

Study of Uncertainties in the Predictions of IITPS Modet

Introduction

Operational Evaluation of IITPS Model Methodology

Results and Discussion

Uncertainty analysis of IITPS Model Taylor Series Approach

First-Order Taylor Series Second-Order Taylor Series Methodology

Results and Discussion

A Case Study ofEffect ofWinds on SO2 and SPM Concentrations

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Delhi

Ambient Air Quality Data Measurements of 502 and SPM Meteorological Data

Results and Discussion Conclusions

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Modelling of Air Pollution from the Power Plant Ash Dumps

Introduction

The Model Formulation Source Strength

The lIT Short Term (IITST) Area Source Model Meteorological Data

Results and Discussions Conclusions

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Chapter 7

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References

Appendix I Appendix II

List of Publications Bio-Data

Conclusions and Future Work Overview ofthe Present Thesis Future Work and Suggestions

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Air quality modelling studies for thermal power plants in some parts of india.