Chemistry Project Methods of reducing air pollution r

Chemistry Project Methods of reducing air pollution

r o t o m f o n o i t u l l o p r i a g n i c u d e r f o s d o h t Me cars

Catalytic Converters (催化轉化器)

Catalytic converters -For cars using unleaded petrol(無鉛汽油) -Convert toxic air pollutants (e. g. CO, NO) in the exhaust to harmless substances (e. g. CO 2, water) -Contain catalysts(催化劑) to speed up the reactions

Catalytic converters - Become ineffective when poisoning or heat deactivation occur Poisoning causes by – lead, sulphur, zinc, manganese, silicon or phosphorus Heat deactivation causes by – Lubricating oil – Engine misfire or ignition failure – A cracked exhaust valve

Reducing Pollutants From Motor Cars By Using Environmental Fuels

Reducing Pollutants From Motor Cars By Using Environmental Fuels Using Unleaded Petrol • • The Hong Kong government banned the sale of leaded petrol in 1999 unleaded petrol comes in combination with the use of a catalytic converter. transform noxious exhaust gases into less undesirable gases. **Car exhaust gas contains a mixture of lead compounds which may cause serious lung diseases!

Reducing Pollutants From Motor Cars By Using Environmental Fuels Liquefied Petroleum Gas • Pollution from motor vehicles is controlled through fuel and emission control. • The Hong Kong government tried to encourage taxi operators to replace diesel taxi with those operated on LPG A LPG taxi

By regulation Control excessive emissions of smoke from car

Air Pollution Control Ordinance At 1990 At 1994 Prohibits the use of high sulphur content solid and liquid fuel for commercial and industrial appliances. Prohibits the sale of leaded petrol At 2003 Requires pre-Euro light diesel vehicles to have emission reduction devices. During public consultation Proposal to Ban Idling Vehicles with Running Engine

Individual method to reduce air pollutants • Using low sulphur content petrol or diesel oil • Using unleaded petrol • Installation of catalytic converters in car exhaust systems • Switching off the engines of idling vehicles • Taking public transport

Government strategies • More stringent fuel and vehicle emission standards. • Encouragement to adopt cleaner alternatives to diesel vehicles, such as the use of Liquefied Petroleum Gas for taxis and light buses. • Installation of old diesel vehicles with devices that, reduce emissions such as particulate traps or catalytic converters. • Promotion of better vehicle maintenance and eco-driving habits.

Results of strategies

u d e r o t Ways s e i r t s indu f o n o i t u l l o p r ce ai

Scrubber(裝置滌氣器) Scrubber is used to remove substances from the exhaust gas stream, or to neutralize those substances. Use of Scrubber : ．can remove up to 95% of SO 2 (二氧化硫). ．Scrubbers mainly use in power plants(發電廠), factories( 廠) and incinerators(焚化爐).

Scrubber(裝置滌氣器) ． Scrubber can be divided into dry and wet scrubber. dry scrubber Scrubber wet scrubber Dry and wet scrubber can be used separately , and also used together.

Scrubber(裝置滌氣器) 1 2 3

Electrostatic precipitators

Electrostatic precipitation • removing fine particulates(細小的微粒) from airstreams(氣流), gases of combustion((燃燒) of fossil-fuel (化石燃料) Dirty gases pass through a strong electric field(電場) dirty gases particulates become charged(帶 電荷) charged particulates are collected by opposite charge’s plants

What can the government do to reduce air pollution caused by the mobile? Vehicles: • sponsor to use LPG (液化石油氣) • Promote good driving habits • Set up monitoring stations(空氣監測站)

What can the government do to reduce air pollution caused by the stationary ? Factory: • Town planning Estate should be away from industry • Implement ordinances Eg: install scrubbers , filters and electrostatic precipitates Power plants(發電廠): • Implement ordinances Factory use natural gas Incinerators(焚化爐): • Replaced by transfer stations Refuse transfer station

Recent measures from the Policy Address 2007 -2008 Regulation: ． to limits the VOC content of products ．requiring power station to use natural gas *note: voc causes smog Mr Donald Tsang

The Present Situation Vehicle Kilometres Travelled and Emission Trend Emissions of nitrogen oxides and particulates from vehicles have been dropping despite an increase in kilometres travelled.

Using petrol is better than using diesel ! Comparison of New Vehicle Exhaust Emission Standards

Reference • http: //en. wikipedia. org/wiki/Catalytic_converter# Three-way_catalytic_converters • http: //www. air-quality. org. uk/25. php • From Wikipedia: • Catalytic converter • http: //en. wikipedia. org/wiki/Catalytic_converter# Three-way_catalytic_converters • Scrubber • http: //en. wikipedia. org/wiki/Scrubber

Group members • • • 5 B Chung Yin Yung (1) 5 B Fung Yuen Yi (3) 5 B Kwan Yu Tung (4) 5 B Yeung Wing Sin (13) 5 B Kwan Man Ho (24) 5 B Kwok Ho Yin (26)