Building Capacities for the Improvement of the Air Quality

Transcription

1 Building Capacities for the Improvement of the Air Quality NOx - Basics Lima, Dr. Hubert Baier General Manager - Europe

2 Names of nitrogen compounds Formula NO N 2 O NO 2 N 2 O 5 N 2 O 3 Systematic Name nitrogen monoxide dinitrogen monoxide nitrogen dioxide dinitrogen pentoxide dinitrogen trioxide Common Name nitric oxide nitrous oxide nitrogen peroxide nitric anhydride nitrous anhydride HNO 3 - nitric acid NH 3 - ammonia 2

3 Formation of NOx Nitrogen - Too much of a good thing Nitrogen is the basic block of nature and is essential for live. Our air consists of Nitrogen as a major compound: Hard to believe that this important and universal element is involved in the creation of significant environmental problems. 3

4 Formation of NOx Nitrogen - Too much of a good thing When Nitrogen becomes reactive its release causes: # acidification and eutrophication # nitrate in drinking and ground water lead to cancer # forest dieback # loss of biodiversity # GHG: nitrous oxide (N 2 O) shows a 298 times larger effect than CO 2 4

5 NOx emissions per capita Latest year available NOx emission per capita (kg) US Germany Peru

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7 Formation of NOx Nitrogen in fuels is converted to oxides of nitrogen in the combustion process. Coal is the most important fuel in this context, as oil and gas contain much lower levels of nitrogen. However, there is a further process in which atmospheric nitrogen and oxygen are combined during high-temperature combustion to form oxides of nitrogen. This occurs in all high-temperature combustion processes and explains why road traffic and electricity generation tend to be among the predominant sources of these gases. The majority of nitrogen oxides formed through this route are emitted as nitric oxide. A smaller amount, typically 5% of the total, is emitted as primary nitrogen dioxide, while the major proportion of atmospheric nitrogen dioxide is a secondary product of atmospheric chemistry. 7

8 Nitrogen oxides at the crossways of atmospheric chemistry This sketch shows the three major emissions that form inorganic fine airborne particulate matter: nitrogen oxides (NOx) largely from vehicles, sulfur dioxide (SO2) from power plants and industrial facilities, and ammonia (NH3) from agricultural activities. Sunlight and chemical reactions in the atmosphere convert the emissions to new chemical species that can combine to form tiny particles known as PM2.5. Published June1, 2016 by Nancy W. Stauffer, MIT Energy Initiative Without a closer look on the nitrogen oxide chemistry, these compounds are the heart of atmospheric chemistry. 8

9 Composition of main fuels In the European Union all available types of fuels are used. Each nation focusses on its own local country wide access. Median composition of fuels (ash free): Mass-% C H N O S Lignite Hard coal Oil S (4.5) Petrol < Wood Gas (CH 4 ) Biogas (CH 4 )

10 Formation of NOx Nitrogen source Reaction partner Mechanism of formation N 2 from air Exhaust gas thermal NOx N N N 2 + O NO + N N + O 2 NO + O Zeldovich-Mechanism strongly related to temperatures >1.250 C Nx from fuel i.e. pyridin from oil C 5 H 5 N Flame front N 2 + CH N + HCN HCN NHx + Ox NOx prompt NOx Fast formation reaction; little relation to temperature fuel NOx Fast reaction >800 C; without correlation to the temperature 10

11 Portion of NOx formation fuel thermal NOx % prompt NOx % fuel NOx % Petrol Gas Heavy oil Hard coal (dry furnace) Hard coal (wet bottom firing) lignite <10 - >90 11

12 NOx-emission 2013 in kt German Sectors of NOx emission (2013)

13 kt German Trend of NOx emission total emission of NOx

14 European legal framework In the past years, the European Union has increasingly set the course in environmental policy: Enforcement of EU Directive 96/61/EC for implementation of Best Available Technique (BAT) for Integrated Pollution Prevention and Control (IPPC) For converting the Commission decision 2000/479/EC an European wide Pollutant Release and Transfer Register (PRTR) was instituted, where emission data on 37 air pollutants and 26 water pollutants emitted by all industrial plants in the European Union are compiled and published on the internet

15 Enforcement of legal framework Proceeding from this legal basis, the competent authorities can order measurements for the first time and recurrently or even for special reasons to be carried out by accredited bodies. Emissions can be determined both by continuous and discontinuous measuring methods, which are described in relevant standards. Continuous measurement is primarily used for dust, NO x, SO 2 and Hg, while the remaining parameters relevant to the ambient pollution legislation are usually determined discontinuously by individual measurements. They are converted to reports, which were collated to the given permissions.

16 NOx formation in coal fired power plants The operator of the plant has to ensure the limits 16

17 NOx formation in coal fired power plants 17

18 Marine and Diesel Power Whether it is tranport or small oil fired power plant, the principle of the generator is the same. Motor Truck engine Credit: DavidDarling.info Marine engine 18

19 Getting the Technic right? This example from the automotive industry shows the classical desaster of the servant of two masters 19

20 Fuel Oil Power Plant For larger applications fuel oil power plants are very similar to coal fired power plants Credit: SystemSeparation Sweden AB 20

21 Coal fired power plants Dry furnace Melting boiler Mass flow of ashes and slag in a dry furnace boiler (left) and a melting boiler (right) 21

22 NO x -Emission Process Emission of NO x molten glass Melting boiler Dry bottom furnace Cement Kiln with De-NOx CFB with De-NOx Temperature

23 New Technology: 23

24 Modern Technology: flue gas (<200 C to gas cleaning) 2-phase-separation (cyclon) steam water lime fuel water steam discharge feed air combustion air (400 C) Circulated Fluidized Bed Combustion Credit: Spektrum Akademischer Verlag Heidelberg 2003 Credit: hs energieanlagen/ Munich

25 NOx-reduction at the clinker burning process Credits: CEMCAT 25