Exam Question
(a) What do you understand by NOx and SOx emissions? (5)
(b) Name the source from where they originate and how? (5)
(c) Briefly discuss, as to how these emissions are dealt with? (10)
Class 4 (4th Engineer)
SSEP
📅 May 2023
Reference Answer
### (a) Understanding of NOx and SOx Emissions (5 Marks)
**1. Nitrogen Oxides (NOx):**
NOx is a collective term for a group of highly reactive gaseous pollutants, primarily comprising Nitric Oxide (NO) and Nitrogen Dioxide (NO2). They are by-products of high-temperature combustion processes.
* **Formation Mechanism:** NOx is formed when atmospheric nitrogen (N2), which constitutes approximately 78% of the air, and oxygen (O2) react under the extreme conditions of high temperature (>1300°C) and pressure found inside an engine's combustion chamber. The formation rate is exponentially dependent on temperature and also influenced by oxygen concentration and residence time at these high temperatures.
**1. Nitrogen Oxides (NOx):**
NOx is a collective term for a group of highly reactive gaseous pollutants, primarily comprising Nitric Oxide (NO) and Nitrogen Dioxide (NO2). They are by-products of high-temperature combustion processes.
* **Formation Mechanism:** NOx is formed when atmospheric nitrogen (N2), which constitutes approximately 78% of the air, and oxygen (O2) react under the extreme conditions of high temperature (>1300°C) and pressure found inside an engine's combustion chamber. The formation rate is exponentially dependent on temperature and also influenced by oxygen concentration and residence time at these high temperatures.
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