Source monitoring Gazala Habib Air pollution sources of regional importance Sources of air pollution Biomass burning Biomass fuel combustion Chemical Fertilizers On-road transport Brick Kilns Dairy Farm Power generation Industries Municipal waste burning Diesel tractors Off-road combustion Construction activity 08/09/23 Approaches for Emission Estimates 2 Area of Research • Emission rate • Emission inventory development • Exposure assessment and risk estimate • To decide control equipment Data requirement • • • • • • • • • • • Gas velocity Gas temperature Static pressure in duct Barometric pressure Duct diameter Concentration of pollutant Emission source name and location Date and time Wind speed and direction Control system operating conditions Process operating conditions Challenges in Aerosol measurement at sources 08/09/23 5 Sampling particles from stack/duct • Isoaxial Sampling • Iso kinetic sampling • Sub iso kinetic sampling • Super iso kinetic sampling • Anisoaxial sampling • Particle size distribution • Particle losses • Wall losses due to charging • Thermophoresis losses • Evaluation parameter for dilution tunnel π£!" = π#,%&'(#! 2βπ π) πΈπ Rotameters with needle valve βπ Dilution tunnel Versatile Source Sampling System (VS3) Rotameter with needle valve Zero air Particle sampling probe DR=10-40 DR=30-100 08/09/23 8 On-field emission measurement images-Residential sector and open burning Outdoor open kitchen 08/09/23 Semi-closed kitchen 9 Evaluation of VS3 v Homogenous mixing v Gas-to particle conversion v Particle wall losses π·π = π" β# − β" = π# β" π ππ ππππππ π‘πππ (π‘) ππππ’ππ ππ ππππ’π‘πππ π‘π’ππππ = πΉπππ€ πππ‘π Phase equilibrium time (t): time required for conversion of VOCs to particles (<0.5 second) Negligible particle losses ! CO2 concentration in longitudinal and axial direction at different dilution ratio had insignificant difference ü The ratio of (π) >4 for achieving phase equilibrium of aerosol inside dilution tunnel (Guo et al. 2016). ! ü At different dilution ratios (π) was always greater than 4 indicated complete gas-to-particle partitioning 10 Jaiprakash et al. AEROSOL SCIENCE AND TECHNOLOGY2016, VOL. 50, NO. 7, 717–731 Velocity measurement and Dilution ratio calculation πΉπππ€ πππ‘π ππ ππππ’π‘πππ πππ π" π·π = = πΉπππ€ πππ‘π ππ ππ₯βππ’π π‘ π# Quantity measured Instruments Range Velocity Pitot tube >5 m/s Hot wire anemometer 50 mm/s - 40 m/s Venturi meter 1 L/s – 100 m3/s Orifice meter 1 cm3/s – 100 m3/s Rotameter 0.01 cm3/s – 50 L/s Mass flow meter 0.1 cm3/s – 2 l/s Laminar flow element 0.1 cm3/s – 20 L/s Spirometer 1-1000 L Soap bubble spirometer 1-1000 cm3 Piston meter 1-1000 cm3 Wet test meter Unlimited Dry gas meter Unlimited Manometer 1-200 kPa [0-2 atm] Micromanometer 0-0.5 kPa [0 – 0.005 atm] Aneroid pressure gauge 0-30 kPa [0-0.3 atm] Bourdon tube gauge >20 kPa [>0.2 atm] Flow rate π" πΆπ$%#&'()*+ − πΆπ$%",-)+#" π·π = = π# πΆπ$%",-)+#" − πΆπ$%(./,#0+ ππππ‘ππππ πππππππ‘πππ‘πππ πΆ1 π2 − π, = π* Volume Pressure Flow rate measurement through particle collection substrate • • • • Variable-head meter-Venturi and orifice meters • Variable area meter- Rotameter • Variable area • Constant pressure • 4/$ 2 βπ π = ππ΄$ π3 π΄ 1− $ π΄4 $ Differential pressure k=0.98 and k=0.62 Critical orifice downstream pressure<0.53*Upstream pressure. Velocity at throat is the speed of sound and further reduction in down stream pressure does not increase the velocity through the throat πΆπππ‘ππππ πππππππ π = 11.7ππ΄6 k=0.98, 0.62 π789 ∝ 1 ππ π»π = 133.3 πππ πππ π = πΆ: π΄6 2ππ2 π3 π΄2 4/$ ü ü ü ü πΆ* = πππ‘ππππ‘ππ πππππππππππ‘ = 0.6 − 0.8 π΄+ = ππππ ππππ ππ‘ πππππ‘ πππ ππ‘πππ π, = πππ π ππ πππππ‘ π΄, = πΆπππ π π πππ‘πππππ ππππ ππ πππππ‘ π4 π4 STP=At sea level t=0 C and p= 1 atm π789 = π;/* π: π789 4/$ = π;/* π: π789 4/$ Source monitoring plan • Source location • Gas flow rate: velocity pressure or Gas kinetic • Measurement of static pressure (velocity pressure=total pressure-static pressure) • Wall type • Static tip • Low pressure • Velocity • Vane probe velocity meter • Mass flow sensor/anemometer • Volumetric flow rate for turbulent flow Carbon balance method for emission factor calculation π£ = π1,*%+=1# 2βπ π3 π£ = π£ππππππ‘π¦ ππ π/π πΆ1,*%+=1# = πππππππππππ‘ πππ π − π‘π¦ππ πππ‘ππ‘ π‘π’ππ βπ = π·ππππππππ‘πππ ππππ π π’ππ π3 = ππππ ππ‘π¦ ππ πππ’π πππ Emission factor calculation πΆ# ×π·π ×π!" π πΈπΉ = ππ πΉ π#& = π£πππ’ππ ππ ππ₯βππ’π π‘ ππππ‘ππππ πππππππ‘πππ‘πππ πΆ# = πΉ = πππ π ππ ππ’ππ π’π ππ The carbon balance method used for emission factor calculation π πΆπ π π0 πΈπΉ= πΆππΉ,.!/ ∗ π π1 π ππ ππ βπΆ + βπΆ 12! 12 0 π12! π π0 πΈπππ π πππ ππ π1 π12 (2.85 − 2.5)×100 = = 11667 1×10&0 ×30 ππ π0 Problem 1b. What would be the concentration in exhaust? Cπππ. ππ ππππ‘πππππ ππ ππ₯βππ’π π‘ = π·π ∗ πΆππππππ‘πππ‘πππ ππ π ππππππ πππ π = πΈπΉ# ×ππ’ππ ππππ π’πππ‘πππ ππ ππ ∗ πππ¦π ππ πππ‘ππ£ππ‘π¦ ππ π π¦πππ ππ Problem 1c. Determine the emission factor of particles if 100 kg of wood was burned in 30 min. πΈπΉ# ππ π, − ππ% ππππ‘ππππ πππππππ‘πππ‘πππ πΆ# ππ π ππππππ πππ π π¦ πΈπΉ Problem 1a. The particle is collected on quartz filter of initial weight 2.5 mg from monitoring of brick kiln stack. The final weight of the filter was measured as 2.85 mg. The monitoring was conducted for 30 min at 1 LPM. Determine the concentration of the particle in sampled air which was diluted using 40 LPM clean air. π πππ π ππ πππππ’π‘πππ‘ ππππ‘π‘ππ = ππ πππ π ππ ππ’ππ ππ’ππππ π 26389 = = 263.89 ππ 100 πΆπππ. ππ ππ₯βππ’π π‘ = 40 ×11667 = 466667 πππ&0 1 Problem 1c. What would be the mass of particles emitted in 30 min if the measured average velocity of exhaust was recorded as 10 m/s? The stack diameter was 2.0 m at sampling point. πππ π ππ ππππ‘πππππ ππππ‘π‘ππ = π!" ∗ πΆππππππ‘πππ‘πππ ππ ππ₯βππ’π π‘ π!" = πΆπππ π π πππ‘πππππ ππππ ππ ππ’ππ‘×π£!" π!" = π 3 2 ×10×30×60 = 56549 π0 4 56549 π0 ×466667 π# ππ π = = 26389 104
