United States          Air Pollution Training Institute    EPA 450/2-80-067
 Environmental Protection     MD20               April 1980
 Agency             Environmental Research Center         i
                 Research Triangle Park NC 27711     C>'
 Air
 A D T I             Do not remove. This document
F^ •II             should be retained in the EPA
X"% f*» m^^^ /I1Q    Region 5 Library Collection.

Control of  Particulate
Emissions
Student  Workbook

-------
United States
Environmental Protection
Agency
Air Pollution Training Institute
MD20
Environmental Research Center
Research Triangle Park NC 27711
EPA 450/2-80-067
April 1980
APTI
Course 413
Control of  Particulate
Emissions

Student  Workbook
Prepared By
O. Beachler
Northrop Services, Inc.
P.O. Box 12313
Research Triangle Park, NC 27709

Under Contract No.
68-02-2374
EPA Project Officer
R. E Townsend

United States Environmental Protection Agency
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711

-------
                                     Notice

  This is not an official policy and standards document. The opinions, findings, and
  conclusions are those of the authors and not necessarily those of the Environmental
  Protection Agency. Every attempt has  been made to represent the present state of
  the art as well as subject areas still under evaluation. Any mention of products or
  organizations does not constitute endorsement by the United States Environmental
  Protection Agency.
                Availability of Copies of This Document

This document is issued by the Manpower and technical Information Branch. Con-
trol Programs  Development Division. Office of Air Quality Planning and Standards.
USEPA. It was developed for use in training courses pirsemed by the EPA Aii Pollu-
tion  Training  Institute and others receiving contractual or grant support from  the
Institute. Other organizations are welcome to use the document for training purposes.

Schools or governmental air pollution control agencies establishing training programs
may  receive single copies of this document,  free of charge, from the Air Pollution
Training Institute, USEPA. MD-20. Research Triangle Park. NC 27711. Others may
obtain copies,  for a fee. from the National Technical Information Service. 5823 Port
Royal Road. Springfield. YA  22161.
                                                •-" AcsauCf

-------
j**08H
           1             AIR POLLUTION TRAINING INSTITUTE
           "    MANPOWER AND TECHNICAL INFORMATION BRANCH
                    CONTROL PROGRAMS DEVELOPMENT DIVISION
                 OFFICE OF AIR QUALITY PLANNING AND STANDARDS
   The Air Pollution Training Institute (1) conducts training for personnel working on the develop-
   ment and improvement of state, and local governmental, and EPA air pollution control programs,
   as well as for personnel in industry and academic institutions; (2) provides consultation and other
   training assistance to governmental agencies, educational institutions, industrial organizations, and
   others engaged in air pollution training activities; and (3) promotes the development and improve-
   ment of air pollution training programs in educational institutions and state, regional, and local
  governmental air pollution control agencies.  Much of the program is now conducted by an on-site
   contractor, Northrop Services, Inc

   One of the principal mechanisms utilized to meet the Institute's goals is the  intensive short term
  technical training course A full-time professional staff is responsible for the design, development,
  and presentation  of these courses In addition the services of scientists, engineers, and specialists
  from other EPA programs governmental agencies, industries, and universities are used to augment
  and reinforce the Institute staff in the development and presentation of technical material

  Individual course objectives and desired learning outcomes are  delineated to meet specific program
  needs through training.  Subject matter areas covered include air pollution source studies,  atmos-
  pheric dispersion, and air quality management  These courses arc presented in  the Institute's  resi-
  dent classrooms and laboratories and at various field locations
    R. Alan Schueler                                             /James A. Jahntie
    Program Manager                                           /  Technical Director
    Northrop Services, Inc.                                         Northrop Services, Inc.
                                   Jean jf Schueneman
                                    Chief, Manpower & Technical
                                    Information Branch
                                            lit

-------
                                TABLE OF CONTENTS

 1-1  Drag Coefficient and Settling Velocity	 1
 1 -2  Settling Velocity and Drag Force  	 2
 2-1  Log-normal  Distribution	 3
 2-2  Log-normal Distribution, Geometric Mean and Standard Deviation	 4
 2-3  Particle Size Distribution	 5
 3-1  Settling Chamber — Minimum Particle Size	 8
 3-2  Settling Chamber —Operating Efficiency	 9
 4-1  Cyclone — Overall Collection Efficiency Using Lapple's Method	10
 4-2  Cyclone — Dimensions and Number of New Cyclones Required	11
 4-3  Cyclone —Overall Collection Efficiency and Mass of Dust Collected	12
 4-4  Cyclone Collection Efficiency	14
 5-1  ESP Problem	17
 5-2  ESP Problem	18
 5-3  ESP Problem	19
 5-4  ESP Problem	20
 6-1  Fabric Filters —Number of Bag Calculations	21
 6-2  Fabric Filters —Number of Bags and Pressure Drop	22
 6-3  Fabric Filters —Number of Bags and Cleaning Frequency	23
 6-4  Fabric Filters —Design of Filter Bag	     	24
7-1  Contact Power Theory Application	25
 7-2  Contact Power Theory Application	           	26
7-3  Cut Power Rule	  27
7-4  Johnstone Equation for Venturi Scrubbers	29

-------
1.1   Drag Coefficient and Settling Velocity
     A spherical limestone particle is 400 /xm in diameter, specific gravity = 2.67.
     Calculate the drag coefficient CD and the settling velocity vt in 70°F air.

-------
1.2  Settling Velocity and Drag Force

     Particles 20 microns in diameter at 70 °F with a specific gravity of 1.8 flow in
     a duct.  The density of H2O is 62.4, the density of air is 0.075 Ik  and the
     viscosity of air is 1.23 X 10" 5Jb_                            ft3
                                 ft-sec.
     (a)  Calculate the settling velocity
     (b)  Calculate the Drag Force

-------
2.1  Log-normal Distribution

     Let's say you have collected some data on particle mass concentration with an
     optical particle counter or an Anderson  Impactor.  The following data was
     collected.

                          dp range        concentration
                          0.1-0.2             10
                          0.2-0.5             13.2
                          0.5-2               20
                            2-5               13.2
                            5-10              10

     How can you tell if these data represent a log normal distribution or some
     other distribution?

-------
2.2  Log-normal Distribution, Geometric Mean and Standard Deviation

                        Given the following particle size data:

                        Size range     Mass concentration
                        dp  n
                          <0.1              0.04
                        0.1- 0.2            0.76
                        0.2- 0.5           15.07
                        0.5- 2.0           68.26
                        2.0- 5.0           15.07
                        5.0-10.0            0.76
                          <10.0              0.04

     Verify that this distribution is approximately log-normal, and find the
     geometric mean and the geometric standard deviation.
     Hint: determine the percentage mass larger than d  max in each size range.

-------
2.3  Particle Size Distribution
     Given the following distributions obtained from size differentiating
     equipment:

             Particle size       Distribution A     Distribution B
             dp (microns)            /tg/m3               ,ug/m3
               <0.62                2575                 875
             0.62-  1.0              33.15               11.05
             1.0 -  1.2              17.85                7.65
             1.2 -  3.0             102.0               40.8
             3.0 -  8.0              63.75               15.3
             8.0 -10.0              5.1                 1.692
               <10.0                7.65                0.008

     (a) Is either distribution A or distribution B log-normal
     (b) If so, what is the geometric mean and standard deviation.

     (Use the sheet of log probability paper provided if necessary.)

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------
3.1  Settling Chamber—Minimum Particle Size
     A hydrochloric acid mist in air at 25°C is to be collected in a gravity settler.
     The unit is 30 ft wide, 20 ft high, and 50 ft long. The actual volumetric flow
     rate of the "acidic" gas is 50 ftVsec. Calculate the smallest mist droplet
     (spherical in shape) that  will be entirely collected by the settler. The specific
     gravity of the acid is equal to  1.6. Assume the acid concentration to be
     uniform through the inlet cross section  of the unit.
     Assume Stoke's Law applies and at 25°C /* = 0.0185 cp,

                              1 cp = 6.72xlO~4-^-
                                               ft-sec

-------
3.2  Settling Chamber — Operating Efficiency
     A gravity settler 5 meters wide, 10 meters long, and 2 meters high, is used to
     trap particles with diameters of 10 /mi. The gas flow rate is 0.4 mVsec per
     second. Calculate the operating efficiency of a settling chamber for the data
     given below. Assume Stokes law regime and a Cunningham correction factor
     of 1.0.
                        Qp= 1.10 gm/cm
                        e = 1.2xlO~3 gm/cm
                                     cm — sec

-------
4.1  Cyclone—Overall Collection Efficiency Using Lapple's Method
     The particle size distribution of a dust from a cement kiln is provided below:
                  Particle size (microns)       %  Wt
                              1
                              5
                             10
                             20
                             30
                             40
                             50
                             60
                          >60
 3
20
15
20
16
10
 6
     The following information is also known:
        Gas Viscosity
        Particle Specific Gravity
        Inlet Gas Velocity to Cyclone
        Effective Number of Turns within Cyclone
        Cyclone Diameter
        Cyclone Inlet Width
     0.02 centipoise (cp)
     2.9
     50 ft/sec
      5
     10 ft
     2.5 ft
     (a) Determine the cut size particle diameter, i.e., diameter of particle col-
         lected at 50% efficiency,  and estimate the overall collection efficiency
         using Lapple's Method.
     (b) If the same cyclone is used, but the inlet gas velocity is increased to 60
         ft/sec and the gas viscosity changes to 0.018 cp (all else remaining the
         same), find the new cut size particle diameter and determine the new
         overall collection efficiency using Lapple's Method.
                                        10

-------
4.2  Cyclone—Dimensions and Number of New Cyclones Required
     A large-diameter conventional cyclone (no vanes) handles 5,000 acfm of a
     particulate-laden gas exhaust stream (QG = 0.076 Ib/ft3) from a certain
     metallurgical operation. The cyclone diameter if 4 ft. The remaining dimen-
     sions may be found from Figure 4.2.1 (in  the manual). In an attempt to
     increase efficiency, a group of new cyclones is to be designed with the same
     geometrical proportions and pressure drop as the  single cyclone. If the
     diameter of the small cyclone is to be 6 in., what  will the dimensions of the
     new group be? How many will be needed to handle the original flow rate at
     the same pressure drop?
                                     11

-------
4.3  Cyclone—Overall Collection Efficiency
     (a)  The size, mass,  and cyclone collection efficiency data for a gas containing
         limestone dust are given below.                           *"
            Particle diameter, /*m    Wt %    Collection efficiency,  %
                    0-5                2                  4
                    5~10               8                  6
                    10-20              13                20
                   20-30              26                32
                   30-50              12                78
                   50-75              11                89
                   75-100              9                95
                  100-200              8                98
                  200-                 11                99 +
    Calculate the overall collection efficiency of the unit.
                                    12

-------
(b)  If the inlet dust loading in the previous problem is 2.2 grains/ft3 and the
    quantity of gas processed is 150,000 acfm, calculate the mass of
    limestone collected daily.
                               13

-------
4.4  Cyclone Collection Efficiency
     Determine loss and collection efficiency for a cyclone from the following
     information.
       (1) collection efficiency curve —figure 1
       (2) size-efficiency curve —figure 2
       (3) size distribution by weight

                         Particle size       %  by Wt
                            Micron         Less than
                               10                 .1
                               15                1.0
                               26               10.0
                               40               32.0
                               67               70.0
                              100               90.0
                            >100             100.0
       (4) weight of inlet loading —50 Ib/hr.
                                        14

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------
ESP Problem
An electrostatic precipitator consists of two parallel 10 ft high by 16 ft wide
plates with corona wires positioned half way between the plates. Find the
effective migration velocity at a flow rate of 35 acfs if the required collection
efficiency is 95%.
                                    17

-------
5.2  ESP Problem
     A horizontal-flow-single-stage electrostatic precipitator is used to remove par-
     ticulates from a dry process gas stream of a Portland cement manufacturing
     plant. The precipitator consists of multiple ducts formed by collecting plates
     14 ft wide by 16 ft high and  placed 9 inches apart. The rate of flow through
     each duct is estimated to be 2400 acfm and the content of dust is 5
     grains/ft3. Assume w = 0.19 ft/sec.
        (a) Calculate the collection efficiency.
        (b) Calculate the amount of dust collected by a duct  each day.
                                        18

-------
5.3  ESP Problem
     An electrostatic precipitator has three ducts with plates  12 ft wide and 12 ft
     high. The plates are 8 inches apart.
     (a) Assuming a uniform distribution of particles and a drift velocity of
         0.4 ft/sec,  calculate the collection efficiency at a rate of flow of
         4,000 acfm at 20°C and 1 atm.
     (b) Calculate the efficiency if one duct were fed 50% of the gas and the
         others 25% each.
                                      19

-------
5.4  ESP Problem
     A precipitator consists of two Stages each with five plates in a series (see figure
     below). The corona wires between any two plates are independently controlled
     so that the remainder of the unit can be operated in the event of a wire failure.
        The following operating conditions exist:
                    Gas Flow Rate         10,000 acfm
                    Plate Dimensions       10  ftx 15 ft
                    Drift  Velocity          19.0 ft/min Section 1
                                           16.3 ft/min Section 2

                                   Top view
                          Stage 1
Stage 2
      (a) Determine the normal operating efficiency.
      (b) During operation, a wire breaks in Stage 1.  As a result,  all of the wires in
         that row are shorted and ineffective, but the others function normally.
         Calculate the collection efficiency under these conditions.
      (c) Similarly, a wire breaks in Stage 2 after Stage 1 is repaired. What is the
         overall collection efficiency of the unit under these conditions?
                                        20

-------
6.1   Fabric Filters—Number of Bag Calculation
     Small scale tests showed that filtration of an  air stream containing one grain
     of particulates per cubic foot of air gave a maximum pressure drop of
     5 inches of water  at a flow rate of 3 ftVmin  per square foot of filtering
     surface.
     (a) Calculate the horsepower required for a fan for a flow rate of
         6,000 ftVmin. through the baghouse.
     (b) Calculate the  number of 0.5 ft diameter  by 10 ft filtering bags required
         for the system.
     Assume an over-all fan-motor efficiency of 63%.

       [flow rate cfm] X [Ap ins. H2O][1.575 X 10 ~4]
  hp =  	—	 (Chemical Engr. Handbook)
                     efficiency (fan)
                                      21

-------
6.2  Fabric Filters—Number of Bags and Pressure Drop
     A plywood mill plans to install a fabric filter as an air cleaning device.
     (a) How many bags, each 8 inches in diameter and 12 ft long, must be used
         to treat the exhaust gas which has a paniculate loading of 2 grains/ft3
         and the exhaust fan is rated at 7,000 ftVmin?
     (b) If the pressure drop is given by the formula
                    Ap = Apclean fabric + Apdust cake
         Estimate the pressure drop after  four hours of operation if the resistance
         coefficients of the filter and dust cake are, respectively. kt - 0.8 inches
         water/ft min. and k2 = 3  inches water/(lb/dust/ft2 cloth area) (ft/min,
         filtering velocity). Assume velocity is 2 ft/min.
                                        22

-------
6.3  Fabric Filters—Number of Bags and Cleaning Frequency
     A plant emits 50,000 acfm of gas with a dust loading of 5 grains ft3. The
     dust is collected by a fabric filter at 98% efficiency when the average filtra-
     tion velocity is  10 ft/min. The pressure drop is given by
                              Ap = 0.2v+5c;v2t
     where:
         Ap is the pressure drop in inches of water,
         v is the filtration velocity in ft/min,
         c; is the dust concentration in lb/ft3 of gas,
         t is the time in minutes since bags were cleaned.
     (a)  How many  cylindrical bags, 1 ft in diameter and 15 ft high will be
         needed?
     (b)  The system  is designed to begin cleaning when  the pressure drop reaches
         8 inches of  water. How frequently should the bags be cleaned?
                                     23

-------
6.4  Fabric Filters—Design of Filter Bag
     It is proposed to install a pulse-jet fabric filter system to clean a 10,000 scfm
     air stream at 250°F, containing 4 grains/ft3 of pollutant. For a 99% effi-
     ciency, the average air-to-cloth ratio is 2.5 cfm ft2 cloth. The following in-
     formation, given by filter bag manufacturers, is available at the beginning of
     the selection process:
       Filter bag               A            B            CD
       Tensile strength      Excellent  Above average    Fair     Excellent
       Recommended
       maximum operation
       temperature, °F         260          275          260        220
       Resistance factor        0.9           1.0           0.5        0.9
       Relative cost
       per bag                 2.6          3.8           1.0        2.0
       Standard size          8"xl6'      10"xl6'      1"X16'     1'X 20'
     (a) Determine the filtering area required for this operation.
     (b) Based on the required area and the above information, select the most
         suitable filter bag and calculate the number of them that should be used.
         The proposal of a pulsed jet device using strong  forces to clean  the bags
         necessitates the selection  of a fabric with  at least above  average  tensile-
         strength.
                                       24

-------
7.1   Contact Power Theory Application
     A vendor proposed to use a spray tower on a lime kiln operation to reduce
     the discharge of solids to the atmosphere. The inlet loading of the gas stream
     from the kiln is 5.0 grains/ft3 and is to be reduced to 0.05 in order to meet
     state regulations. The vendor's design calls for a water pressure drop of 80 psi
     and a pressure drop across the tower of 5.0 in. H2O. The gas flow rate is
     10,000 acfm, and a water rate of 50 gal/min  is proposed. Assume the con-
     tact power theory to apply.
     (1) Will the spray tower meet regulations?
     (2) What total pressure loss is required to meet regulations?
     (3) Propose  a set of operating conditions that  will meet the standard. The
        maximum gas and water pressure drop across the unit are 15 in. H2O and
        100 psi,  respectively.
     (4) What conclusions can  be drawn concerning the use of a spray tower for
        this application.
                                     25

-------
7.2  Contact Power Theory Application
     The installation of a venturi scrubber is proposed to reduce the discharge of
     particulates from an open-hearth steel furnace operation. Preliminary design
     information suggests a water and gas pressure drop across the scrubber of
     5.0 psi and  36 in.  H2O, respectively. A liquid-to-gas ratio of 6.0
     gal/min/1,000 acfm is usually employed in this application. Estimate the
     collection efficiency of the proposed venturi scrubber. Assume contact power
     theory to apply.
                                      26

-------
7.3   Cut Power Rule
     What would be the pressure drop required on a venturi scrubber to achieve
     an overall collection efficiency of 99.3% for  paniculate matter having a mass-
     median aerodynamic diameter of 5^m with particle size deviation,  a ,  of 2.0 /
                                    27

-------An error occurred while trying to OCR this image.

-------
7.4  Equation for Venturi Scrubbers
     A fly ash laden gas stream is to be cleaned by a venturi scrubber using a
     liquid-to-gas ratio  of 8.5 gal/1000 ft3. The efficiency can be calculated from
     Where f]-l is the fractional efficiency of collection of particles of size dpi.  The
     fly ash has a particle density of 0.7 gm/cm3,  and k = 200 ftVgal.
     Use a throat velocity of 272 ft/sec, a liquid-to-gas  ratio of 8.5 gal/1000  ft3,
     and a gas viscosity of 1.5 X 10 ~5 Ib/ft sec. The particle size distribution  is:
                     dpi (microns)              % by Weight
                           <= 0.10                    0.01
                       0.1    0.5                     0.21
                       0.6   1.0                     0.78
                       1.1    5.0                    13.0
                       6.0-10.0                    16.0
                      11.0-15.0                    12.0
                      16.0-20.0                     8.0
                          > 20.0                    50.0
     Make use of the Nukiyama  and Tanasawasa relationship.
                                       29

-------
                                   TECHNICAL REPORT DATA
                           (Please read Instructions on the reverse before computing)
                           !	       - -           	*   •    i  o i-T
                                                            RECIPIENT'S ACCESSIOJ*NO
4. TITLE AND SUBTITLE

  APTI  Course 413
  Control of Participate  Emissions
  Student Workbook
7 AUTHOR(S)
  D.  S.  Beachler
9 PERFORMING ORGANIZATION NAME AND ADDRESS
  Northrop Services,  Inc.
  P.  0. Box 12313
  Research Triangle  Park,  NC  27709
 12. SPONSORING AGENCY NAME AND ADDRESS

  U.S. Environmental  Protection Agency
  Manpower  &  Technical  Information Branch
  Research  Triangle Park, NC  27711

 15. SUPPLEMENTARY NOTES
            . REPORT DATE
              April 1980
           6. PERFORMING ORGANIZATION CODE
             PERFORMING ORGANIZATION REPORT NO.



           10. PROGRAM ELEMENT NO.

              B18A2C
           11. CONTRACT/GRANT NO.
                                                              68-02-2374
            13 TYPE OF REPORT AND PERIOD COVERED
               Student Workbook
            14. SPONSORING AGENCY CODE
  EPA Project Officer for this workbook is R. E. Townsend,  EPA-ERC, MD-17, RTP,  NC  2771
 16. ABSTRACT
  . AB£p I M«U I                                                                    if       /IT?
  This workbook contains problems  for the Air Pollution Training Institute s Course 413
  "Control  of Particulate Emissions".  The problems cover  calculation of collection
  efficiencies  pressure drop  values, and particle size distributions for  such
  emTss  on co ntrSl devices  as  settling chambers, cyclones, electrostatic P'ecipitators,
  Smhnisps  and wet collectors.   The workbook, when  used  with the Student Manual,
  E?A 450/2180 066!du?ing  the lecture sessions, is part of comprehensive  training in
  particulate control.

  The course also has an  Instructor's Guide, EPA 450/2-80-068, which should  be  used
   in conducting the  course.
                                                                                       	
                                 KEY WORDS AND DOCUMENT ANALYSIS
                   DESCRIPTORS
   Personnel  training
   Air  pollution control
   Dust collectors
    DISTRIBUTION STATEMENT

    Unlimited
                                                I.IDENTIFIERS/OPEN ENDED TERMS
                                                Training Exercises
19. SECURITY CLASS (ThisReport)
  Unclassified	
                                                20. SECURITY CLASS (This page)

                                                  Unclassified
                             COSATI Field/Group

                             13B
                              51
                             68A
21. NO. OF PAGES
   34
                           22. PRICE
  EPA Form 2220-1 (9-7»)
                                               30

-------