Chapter 8 Cont’dLecture 14

Acid Rain

Smog

http://www.eoearth.org/article/Acid_rain

http://www.eoearth.org/article/Acid_rain

Effects of Acid Rain – Outdoor Objects

Over long periods of time this affects:

–National monuments• Mt. Rushmore• Statue of Liberty

–Buildings• Sears Tower• Empire State Building

–Vehicles (paint)–Homes (siding)

This photograph shows a small section of masonry from a church in northern France.

The rock was originally a smooth pillar like structure forming part of the outside decoration of the building. Over the last hundred years or so, acidic rain water has constantly dripped onto the rock from a rain gutter several meters above it.

http://www.geography-site.co.uk/pages/environ/acid.html

Ways to Reduce Acid Rain

• Use energy in a more efficient way

• Use cleaner fuel that contributes less to acid rain

• Clean regular fuel before burning

• Burn regular fuel and remove SOx and NOx before released into atmosphere

• Burn regular fuel in a way that produces less SOx and NOx

Using Cleaner Fuels

For example use WY coal that contains less sulfur– Advantages

• Would meet clean air regulations• Probably would not require new equipment

– Disadvantages• Lower heating value; more coal needed to get same energy• Higher moisture content; hauling “useless” water• Harder to grind; more energy used for this• May contain higher levels of toxic trace elements (mercury)

Clean Regular Fuel Before Burning

• Advanced Physical Cleaning– Requires grinding to very small particles; very costly– Only removes pyritic sulfur– Difficult and costly to dry large amounts of clean coal

• Chemical Cleaning– React coal with strong acid or base– Expensive and toxic chemical remains in the cleaned

coal

• Biochemical Cleaning– Use very selective microorganisms to react with coal– Takes time and money

Burn Regular Fuel & Clean Exhaust Before Entering Atmosphere

• Filters– Electrostatic precipitator (ESP)

• Metal plates are electrically charged

• As particles (SOx, NOx) flow past the plates they become oppositely charged than the plates and are attracted to them

• They stick to the plates and attract other particles• At some point the stuck particles must be removed to begin the

process again

• Add an adsorbent that adheres to the SOx

– This can be removed as a dry power or wet slurry before the exhaust

• Some NOx and SOx (pollutants) removed at 1st ESP• More pollutants removed by injecting calcium-limestone• Smallest pollutants removed at 2nd ESP

Burn Regular Fuel & Clean SOx and NOx Before Entering Atmosphere

Burn regular fuel in a way that produces less SOx and NOx

• Goal is to burn fuel with N (coal) with less oxygen initially– More N turns into

hydrogen cyanide (HCN) that can be removed

• After HCN is made then add necessary amount of air to complete reaction

Burn regular fuel in a way that produces less SOx and NOx

• Heating up coal in oxygen deficient atmosphere causes N and S to form molecules which are easier to remove

• Add sufficient oxygen afterwards

Burn regular fuel in a way that produces less SOx and NOx

• Inject coal, limestone, and air into “Bubbling bed”

• This design removes much of the pollutants before they enter exhaust gas

Fig. 8-21, p. 279

Table 8-2, p. 258

Fig. 8-7, p. 251

USA - 2003

< 10 µm

Fig. 8-8, p. 254

Fig. 8-9, p. 260

Los Angeles Basin

Fig. 8-11a, p. 262

Fig. 8-11b, p. 262

History of NAAQS

• 1971, EPA NAAQS (National Ambient Air Quality Standard) for particulate matter under Section 109. The standard was the "high-volume" sampler. This type

of sampler collects particulate matter up to a size of 45 micrometers in diameter, called "total suspended particulate" (TSP).

• 1987, PM10 was created and abolished the TSP standard.– Recognizing the risks of adverse health effects associated with smaller particles that are

more likely to penetrate deeper into the respiratory system, EPA created a new particulate matter standard, based upon particles with a diameter of 10 microns or less (PM10 ). standard.

• 1997, PM 2.5 Standard was created as a new size-specific indicator for particulate matter, EPA concluded that PM10 would not provide the most effective

and efficient protection from the detrimental health effects of particulate matter. – create a new annual PM2.5 standard of 15 µg/m3. – create a new 24-hour PM2.5 standard of 65 µg/m3. – retain the current 24-hour PM10 standard of 150 µg/m3.

• 2001, the United States Supreme Court upheld EPA's authority under the Clean Air Act to set national ambient air quality standards for the protection of public health.

• 2002, the D.C. Circuit court rejected all of the remaining challenges to the standard. With the resolution of these legal issues, EPA began developing new

strategies for implementation of the PM 2.5 standards. • 2004, EPA designated areas not in attainment with the standard.  

Table 8-5, p. 268

Fig. 8-13, p. 269

1998

Fig. 8-20, p. 278

Fig. 8-17, p. 275

ESP Before & After

CO Picture from Terra Satellite

Fig. 8-19, p. 278

Fig. 8-14, p. 271

Table 8-4, p. 267

Table 8-6, p. 272

Table 8-3, p. 265

Project #2

Engr 303I

Due

August 3, 2009

Project 2• Home retrofit for Solar Thermal Hot Water and

Wind Mill Electricity (max. 10 kW)• Use the following criteria for your selection:

1. Do not attempt to design custom components. Go online and select ones that have been built and use those specifications for your project. Explain your choices and where you found the information.

2. Solar thermal is for hot water heater, not home heating.

3. Explain your reasoning in all selection criteria.

4. Sites can be anywhere in Illinois, where you work off of an existing home & its energy needs.

Format

• Title page with title, Site Location, team personnel• Table of contents with each person’s name next to their

responsibility• Short text with pictures to illustrate project area• Important List all assumptions used in this report• Maps showing global, regional, and local site• Summary paragraph

– Summary of selection criteria– Include estimated cost of land and project

• Any calculations conducted during this project