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Emissions Calculations 101

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Emissions Calculations 101 Tim Trumbull Iowa Air Emissions Assistance Program Iowa Waste Reduction Center University of Northern Iowa Step 1- Calculate Annual ... – PowerPoint PPT presentation

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Title: Emissions Calculations 101


1
Emissions Calculations 101
  • Tim Trumbull
  • Iowa Air Emissions Assistance Program
  • Iowa Waste Reduction Center
  • University of Northern Iowa

2
Estimating Emissions
  • Developing emission control strategies
  • Determining affects of sources and mitigation
    strategies
  • Emissions Inventories
  • Permit Applications

3
Estimation Hierarchy
4
Preferred Method of Estimating Emissions
  • Continuous Emission Monitoring
  • any monitoring effort that continuously
    measures ( I.e. very short averaging time) and
    records emissions
  • Very expensive but most accurate

5
Second Best Method of Estimating
  • Stack Test Data
  • Short term scientific tests to quantify an
    emission rate
  • Results are applicable only to the conditions
    existing at the time of the test
  • Reliable and somewhat expensive

6
Third Method of Estimating Emissions
  • Material Balance
  • Reliable average emission rate
  • For use when a high percentage of material is
    lost to the atmosphere
  • May be inappropriate when a material is consumed
    or combined in a process
  • Need to account for all materials going into and
    coming out of a process

7
Fourth Method of Estimating Emissions
  • Emission Factors
  • Ratios that relate emissions of a pollutant to an
    activity level that can be easily measured .
  • Given an emission factor, simple multiplication
    can yield an estimate of emissions
  • Represent typical values for an industry, not
    necessarily representative of a specific source

8
Fifth Method of Estimating Emissions
  • Engineering Estimates
  • Term applied to the best approximation that can
    be made when stack testing, material balance, or
    emission factors are not available.
  • Usually made by an engineer familiar with a
    specific process, and is based on process
    information

9
Material Balance
  • Commonly used for surface coating operations
  • Required Process rates, material used, material
    properties (from MSDS), and knowledge of process
  • Example Spray Paint Booth

10
Material Balance
  • Sample Exercise

11
ACMEs Spray Paint Booth
  • ACME Corp. applies a base coat and a top coat to
    each wagon it produces. The paint is sprayed
    directly from the container with no thinning or
    mixing. ACME has a federally enforceable paint
    usage limit of 2000 gallons per year. ACME
    sprayed 1,300 gallons last year (500 gallons of
    base coat and 800 gallons of topcoat). An HVLP
    spray gun with a maximum capacity of 7 gal./hr is
    used. The paint booths filters have a 95
    percent particulate removal efficiency.

12
MSDS Information
All percents are weight percents and expressed as a percent of total paint weight Top Coat Base Coat
Paint Weight (lbs/gal) 8.75 7.21
VOC 25 42
Solids 75 58
Xylene 8 2
Toluene --- 15
MEK 2 ---
13
Step 1- Determine paint usage
  • Since ACME has a usage limit of 2,000 gal/yr,this
    is the maximum amount of paint that they can use.
  • If this limit was not in place potential usage
    would be calculated as follows
  • Gun capacity x hours/yr gallons / year
  • 7.0 gal/hour x 8760 hr/yr 61,320 gal./yr.

14
Step 2- Calculate Potential VOC and HAP emissions
Top Coat Base Coat
Paint Weight (lbs/gal) 8.75 7.21
VOC 25 42
Solids 75 58
Xylene 8 2
Toluene --- 15
MEK 2 ---
  • Use the highest constituent amount of VOC and
    HAPs from the base or top coat to calculate
    potential emissions.
  • First, determine which paint has the highest
    amount of VOC.
  • Base7.21lb/gal x .42 3.02 lb/gal
  • Top 8.75 x .25 2.01 lb/gal

15
Step 2- Calculate Potential VOC and HAP emissions
(cont)
  • Density (lb/gal) x Usage Limit (gal/yr) x Max.
    VOC x ton/2000 lb
  • (7.21 lb/gal) x (2000 gal/yr) x 0.42 VOC x (1 ton
    / 2000 lbs)

  • 3.02 Tons / year VOC
  • Use the same formula for each HAP but replace VOC
    with the highest specific HAP from the two
    coatings
  • Xylene 8.75 lb/gal x 2000 gal/yr x 0.08 x
    ton/2000 lb 0.7 tons/yr
  • Toluene 8.75 lb/gal x 2000 gal/yr x 0.15 x
    ton/2000 lb 1.31 tons/yr
  • MEK 8.75 lb/gal x 2000 gal/yr x 0.02 x ton/2000
    lb 0.18 tons/yr

16
Step 3 Calculate Potential PM-10 Emissions
  • To calculate PM-10 emissions the spray transfer
    efficiency (TE) of the spray gun and the control
    efficiency (CE) of the filter must be inserted
    into our earlier formula for VOC.
  • Transfer Efficiency is the percentage of paint
    from the gun that adheres to the part being
    painted.

17
Step 3 Potential PM-10 Emissions (Sample
Transfer Efficiencies)
Method of Spraying Flat Surface Table Leg Surface Bird Cage Surface
Air Atomized 50 15 10
Airless 75-80 10 10
Electrostatic Disk Airless Air Atomized 95 80 75 90-95 70 65 90-95 70 65
18
Step 3 Calculate Potential PM-10 Emissions
(cont)
  • The HVLP gun has a transfer efficiency of 65
  • The filter control efficiency (CE) is 95
  • In ACMEs process, 65 of the paint sprayed hits
    the part and 35 enters the exhaust stream.
  • The filter captures 95 of the solids in the
    exhaust.
  • The remaining 5 is discharged up the stack

19
Step 3 Potential PM-10 Emissions (cont)
  • Calculations
  • Density (lb/gal) x Usage Limit x Max solids x
    (1-TE) x (1-CE) x ton / 2000 lbs.
  • ton/yr PM-10
  • 8.75 lb/gal x 2000 gal/yr x 0.75 x (1-.65) x
    (1-.95) x ton/2000 lbs 0.11 tons/yr PM-10

Top Coat Base Coat
Paint Weight (lbs/gal) 8.75 7.21
VOC 25 42
Solids 75 58
Xylene 8 2
Toluene --- 15
MEK 2 ---
20
Step 4- Calculate Maximum Hourly Emissions
  • Multiply the capacity of the gun by the weight of
    the heaviest paint and by the highest percentage
    amount of each constituent.
  • The paint density multiplied by the percent of
    the pollutant (by weight) equals a pound per
    gallon emission factor.
  • To calculate hourly PM-10 emissions the transfer
    efficiency and collection efficiency must be
    included in the formula

21
Step 4- Calculate Maximum Hourly Emissions (cont.)
  • Gun Capacity (gal/hr) x Density (lb/gal) x Max.
    VOC/HAP VOC or HAP
  • Gun Capacity (gal/hr) x Density (lb/gal) x Max
    PM-10 x (1-TE) x (1-CE) PM-10
  • VOCs 7 gal/hr x (8.75 lb/gal x 0.42) 25.73
    lb/hr VOC
  • Xylene 7 gal/hr x (8.75 lb/gal x 0.08) 4.9
    lb/hr Xylene
  • Toluene 7 gal/hr x (8.75 lb/gal x 0.15) 9.19
    lb/hr Toluene
  • MEK 7 gal/hr x (8.75 lb/gal x 0.02) 1.23 lb/hr
    MEK
  • PM-10 7 gal/hr x (8.75 lb/gal x 0.75) x (1-.65) x
    (1-.95) 0.8 lb/hr PM

22
Step 5- Calculate Actual Annual VOC and Toxic
Emissions
  • Emissions from each coating must be calculated
    and added together.
  • Paint used (gal/yr) x Paint Weight (lb/gal) x
    Pollutant x ton/2000 lbs. Actual Tons/
    year
  • VOC-Top Coat
  • 800 gal/yr x (8.75 lb/gal x 0.25) 1,750 lb/yr x
    ton/2000 lb 0.875 TPY VOC
  • VOC- Base Coat
  • 500 gal/yr x (7.21 lb/gal x 0.42) 1,514 lb/yr x
    ton/2000 lb 0.75 TPY VOC

  • 1.63
    TPY VOC

23
Step 5- Calculate Actual Annual VOC and Toxic
Emissions
  • Xylene -Top Coat
  • 800 gal/yr x (8.75 lb/gal x 0.08) 560 lb/yr x
    ton/2000 lb 0.28 TPY Xylene
  • Xylene- Base Coat
  • 500 gal/yr x (7.21 lb/gal x 0.02) 72.1 lb/yr x
    ton/2000 lb 0.04 TPY Xylene

  • 0.32 TPY
    Xylene
  • Toluene -Top Coat
  • 800 gal/yr x (8.75 lb/gal x 0.0) 0.0 lb/yr x
    ton/2000 lb 0.00 TPY Toluene
  • Toluene- Base Coat
  • 500 gal/yr x (7.21 lb/gal x 0.15) 540.75 lb/yr x
    ton/2000 lb 0.27 TPY Toluene

  • 0.27 TPY
    Toluene

24
Step 6- Calculating annual PM-10 Emissions
  • Use the same formula with the incorporation of
    Transfer and Control Efficiencies
  • Top Coat
  • 800 gal/yr x (8.75 lb/gal x 0.75) x (1-.65) x
    (1-.95) 122.5 lb/yr x ton/2000 lb
    0.05 Tons/yr PM-10
  • Base Coat
  • 800 gal/yr x (7.21 lb/gal x 0.58) x (1-.65) x
    (1-.95) 63.09 lb/yr x ton/2000 lb
    0.02 Tons/yr PM-10

  • 0.07 TPY PM-10

25
Emission Factors
26
Emission Factors
  • An emission factor is a representative value that
    attempts to relate the quantity of a pollutant
    released to the atmosphere with an activity
    associated with the release of that pollutant.
  • In most cases, EFs are an average of all
    available data of acceptable quality and are
    generally assumed to be long-term averages for
    all facilities in the source category.

27
Emission Factors
  • General Equation for Emission Estimation
  • E A x EF x (1-ER/100)
  • Where
  • E emissions
  • A activity rate
  • EF emission factor
  • ER overall emission reduction efficiency,
  • further, ER is the efficiency of the control
    system

28
Sources of Emission Factors
  • AP-42- includes descriptions of activities that
    produce emissions
  • FIRE- The Factor Information Retrieval Data
    System menu driven software
  • Air CHIEF 9.0 CD-ROM- includes AP-42 and FIRE
  • TANKS- estimates VOC HAP emissions from tanks
  • CHIEF Bulletin Board System- includes latest
    guidance and information on air emission
    inventories and emission factors
  • available at www.epa.gov/ttn/chief

29
Other Sources of Emission Factors
  • State Published Emission Factors
  • Vendor Supplied Emission Factors

30
Emission Factor Example
  • ACME Company has a welding station that it uses
    to construct wagons.
  • Process Gas Metal Arc Welding, E308 electrode
  • Maximum Feed Rate 30 lb. electrode per hour
  • Actual Throughput 40,000 lbs. Electrode per
    year

31
Air CHIEF to find Emission Factors
32
(No Transcript)
33
ACMEs Welding Station
  • SCC No. 30905212
  • Emission Factors
  • (HAPs from table 12.19-2)
  • PM-10 5.4 lbs/1000 lb of electrode consumed
  • Cr 0.524 lbs/1000 lb of electrode consumed
  • Mn 0.346 lbs/1000 lb of electrode consumed
  • Ni 0.184 lbs/1000 lb of electrode consumed

34
Step 1- Calculate Annual Potential
  • Make sure units of rate and emission factor
    match.
  • 30 lb/hr x lb/1000 lb 0.03 1000 lb/hr
  • 0.03 1000 lb/hr x 5.4 lb/1000 lb x 8760 hr/yr x
    ton/2000 lb
  • 0.71 tons/yr PM-10
  • Potential Chromium 0.07 tons/yr
  • Potential Manganese 0.05 tons/yr
  • Potential Nickel 0.02 tons/yr

35
Step 2- Calculate Actual Emission
  • Actual PM-10 in tons per year
  • 40 1000 lb/yr x 5.4 lb/1000 lb x ton/2000 lb
    0.11 tons/yr
  • Use the same formula for the other HAPs with
    their corresponding emission factors
  • Actual Chromium 0.01 tons/yr
  • Actual Manganese 0.01 tons/yr
  • Actual Nickel 0.00

36
Emission Factor Cautions
  • Because emission factors are an average, 50
    percent of sources will have rates above or below
    the factor used
  • Emission factors are neither emission limits nor
    standards
  • If a factor for a pollutant is not available from
    EPA, this does not mean that the source does not
    emit a pollutant

37
Questions? Contact Info
  • Phone 800-422-3109
  • E-mail trumbull_at_uni.edu
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