1

Module 1

Air Pollution OverviewMaterial Balances

MCEN 4131/5131 Modulel 1 1/23/06

2

What are we doing in class today?

• Preliminaries– Handouts for Thursday’s SIP project– Office hours OK?– Do you have a clicker?– Is it registered?– Solutions to odd-numbered HW problems in back of

book, remember you can work in groups– Do not do HW problem 1.21

• Review material and quiz• In-class problems

– Conversions– Material balances

MCEN 4131/5131 Modulel 1 1/23/06

3

Educational Objectives

• Name the NAAQS criteria pollutants and the standard values for PM2.5, CO, O3

• Define Prevention of Significant Deterioration (PSD)

• Describe and apply the New Source Performance Standards (NSPSs)

• Describe the major air pollutants of concern, their major sources and why they are of concern (PM, SO2, NOx, VOCs and photochemical oxidants, CO)

• Apply the ideal gas law • Convert from ppm to gm3

• Solve material balance problems

MCEN 4131/5131 Modulel 1 1/23/06

4

Clicker Question

• Which of the following is not a criteria pollutant?

a. Particulate leadb. Nitric oxidec. PM2.5

MCEN 4131/5131 Modulel 1 1/23/06

5

Air Pollution Control Strategies

• The Emission Standard (e.g. NSPS)– Focuses on the emitter– Best available control technology (BACT)– Not very cost effective, but easy to enforce

• The Air Quality Standard (e.g NAAQS)– Focuses on human health and welfare effects– Need to tie to emissions to enforce

• Emissions Tax (e.g. miles-specific vehicle tax, Carbon emissions tax)– Economic incentives to pollute less

• Market Control, Emission Rights (e.g. carbon trading)– Polluters trade amongst themselves a limited amount of

credits

MCEN 4131/5131 Modulel 1 1/23/06

6

Emissions Trading

• Implemented in 2005 in Europe– Goal is to reduce greenhouse gases and is

based on permits for carbon use– Industry allocated targets for emissions of CO2 – if they beat these they will be able to sell

permits to other businesses – If companies want to exceed their pollution

allocations they will pay penalties or buy permits from other businesses

– UK estimates that scheme will cost 1.2 billion USD

• http://www.co2e.com/

MCEN 4131/5131 Modulel 1 1/23/06

7

Clicker Question

• In the CAAA of 1977, PSD of air quality in regions cleaner than the NAAQS was added. A Class I area was defined as:

a. An urban areab. Farmlandc. A pristine area

MCEN 4131/5131 Modulel 1 1/23/06

8

New Source Review Permitting Program

• President Bush made overhauling the NSR one of his top environmental priorities

• National Academy of Sciences reviewed Bush’s NSR program– Suggests that Bush’s plans to reform the CAA

are likely to allow higher emission levels at individual electric utility plants than the current NSR program

• Clear Skies Bill proposed in 2005 but never passed in congress

• EPA implemented CAIR in 2005

MCEN 4131/5131 Modulel 1 1/23/06

9

You the Engineer and Permitting

• The CAAA of 1990 requires that states administer permits for sources that potentially emit a controlled pollutant at a rate greater than the standard, for that type of source

• You are required to look at CU’s Power house, which produces electricity and steam (heating) for CU and the Williams Village Dormitory

MCEN 4131/5131 Modulel 1 1/23/06

10

SPECS

• Because it has the potential to emit:• >100 tons/yr of NOx• >100 tons/yr of CO• And it is in a non-compliance area

for ozone (http://www.compliancepublishers.com/cc/cc1103.htm)

• Then it must get an operating permit

MCEN 4131/5131 Modulel 1 1/23/06

11

What you do

• You examine the plant, note type of equipment and find the turbines are subject to NSPS

• Emissions limits for this kind of turbine are already outlined (NOx)

• You recommend low-excess-air firing for the combustors (chapter 16, p 508)

• You also require the plant install equipment for measuring flowrates, pollutant concentrations, etc.

• You outline a reporting schedule

MCEN 4131/5131 Modulel 1 1/23/06

12

Clicker Questions

• What is Title I of the 1990 CAA?a. Mobile sourcesb. Acid depositionc. NAAQS

• What is the PM2.5 standard?a. 15 g/m3 annual, 65 g/m3 24 hourb. 50 g/m3 annual, 1500 g/m3 24

hour

MCEN 4131/5131 Modulel 1 1/23/06

13

Transport, Dilution, Alteration

Removal

Source ExposureTransport and Fate

ACMEWidget Co.

Install controls here

MCEN 4131/5131 Modulel 1 1/23/06

14

Sources

• Air pollution sources include anything that releases anything to the air.– Power plants – electricity production– Factories, refineries– Painting– Cars and trucks– All buildings – cleaning products, heating, cooking,…– All people

• let’s look at some of the prominent pollutant species.

MCEN 4131/5131 Modulel 1 1/23/06

15

Particulate Matter

• Caused by– Materials-handling processes– Combustion– Gas conversion reactions

• Affects– Visibility– Human health– Soiling of artifacts, electronics

Fine particles

MCEN 4131/5131 Modulel 1 1/23/06

16

• London Fog• Donora, PA• Chimney sweeps

Fine PM is associated

with mortality

MCEN 4131/5131 Modulel 1 1/23/06

17

Sulfur Dioxide

02468

1012141618

millions of tons/yr

transportationelectric utilitiesindustrial furn...residential/otherchemicals/petr...metals processing

other industries

1998 SO2 emission estimates

Vegetation damage, respiratory irritation, acid rain

MCEN 4131/5131 Modulel 1 1/23/06

18

Clicker Question

• What is a main product of reactions that involve VOCs and NOx and sunlight?

a. Carbon monoxideb. Benzenec. ozone

MCEN 4131/5131 Modulel 1 1/23/06

19

Nitrogen Oxides

0369

1215

millions of tons/yr

transportationstationary

1998 NOx emission estimates

Smog, vegetation damage, respiratory irritant, visibility

MCEN 4131/5131 Modulel 1 1/23/06

20

Carbon monoxide

01020304050607080

millions of tons/yr

transportationstationary

1998 CO emission estimates

Health effects - slight headaches to death(>500/yr die due to fuel-burning appliances, 1000’s get sick)

Residential heating Important!

MCEN 4131/5131 Modulel 1 1/23/06

21

Tools of the Trade

• Ideal gas law• Material balance • Energy balance

MCEN 4131/5131 Modulel 1 1/23/06

22

STP

• Standard temperature value in air pollution is?

• 25 °C• Standard pressure value is?• 1 atm

MCEN 4131/5131 Modulel 1 1/23/06

23

MW Calculation

• For each molecule, find (memorize) atomic weight from periodic table

• Molecular weight = sum of atomic wts

• Units are g/gmol, lb/lbmol, kg/kgmol

MCEN 4131/5131 Modulel 1 1/23/06

24

Ideal Gas Law

€

ρ=M

V=

(P)MW

RT

Mass concentration

Partial Pressure(can be expressed as ppm)

MCEN 4131/5131 Modulel 1 1/23/06

25

Clicker question (group)

• TOOL: Use the ideal gas law to convert between ppm and g/m3

• Convert the NO2 AQS of 100 g/m3 to ppm

• DATA: T=23 C, R=0.08206 atm-L/K-mol, P = 1 atm

• Molecular weights? a. 0.35 ppmb. 0.053 ppmc. 4.2 ppm

MCEN 4131/5131 Modulel 1 1/23/06

26

…and again…

• Now convert a CO concentration of 35 ppm to g/m3.

MCEN 4131/5131 Modulel 1 1/23/06

27

Clicker question

• Given a flow rate of 30 L/min at 20C and 790 mm Hg

• What is the flow rate at 200C and 730 mm Hg

a. 52 L/minb. 45 L/minc. 17 L/min

MCEN 4131/5131 Modulel 1 1/23/06

28

Material Balances

• Mass and heat balances are at the core of unit operations

• Mass is neither created nor destroyed, may change form like in a chemical reaction

• Same with energy