Microsoft Word master thesis report fina doc

4.6.1. Normal operations ..................................................................................................................... 54
4.6.2. Intermittent operations ............................................................................................................. 54
4.7.
E
MISSIONS REDUCTION PROPOSALS
............................................................................................... 55
CONCLUSION .................................................................................................................................... 55
REFERENCES .................................................................................................................................... 56

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Introduction 
Refineries and petrochemical processes are responsible for many emissions both into the air 
and into the water. Most relevant emissions into the air are nitrous oxides (NOx), sulfur 
oxides (SOx), carbon monoxide (CO), methane and volatile organic compounds (VOC). 
Waste water from petroleum industry contains organic compounds, phenols, toxic metals and 
other pollutants such as iron, dissolved and suspended solids, oil, cyanides, sulfides and 
chlorine. In order to reduce these emissions, an accurate analysis of processes is necessary. 
The analysis of some processes leads to two conclusions: 
On the one hand, we can see that major part of emissions always come from the same sources:
- Fugitive emissions, responsible for VOC releases to the atmosphere. 
- Process heaters and boilers, responsible for NOx, SOx and particulate matters releases to the 
atmosphere. 
- Blowdown systems 
For each of these sources, theoretical methods to qualify and quantify pollutants emitted, and 
treatment methods available and pollutant production reduction methods are analyzed. 
On the other hand, we can see that particular pollutants are emitted from some processes, in 
normal or intermittent functioning. For example, dioxins can be produced during catalyst 
regeneration of reforming and isomerization units. Usually these kinds of emissions are not 
taken into account for different reasons: the formation mechanism of these pollutants is not 
well-known (dioxins), the emission occurs rarely (catalyst in-situ regeneration), etc.
Aim and objectives 
The aim of this study is to carry out a general environmental assessment of refineries and 
petrochemical processes. The first part of this report emphasizes on major emissions sources 
and gathered general solutions available and applicable. The second part of this report 
lightens particular processes. A methodology to analyze processes is proposed. 
Methodology 
This report is based on a bibliographic study for general considerations. Process books 
produced by Axens are used for the analysis of particular processes. When it comes to 
characterize emitted pollutants, only theoretical methods are given, it means that 
measurements or monitoring techniques are not taken into account. 

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