1. Unit Processes of Air Pollution Control Benno Rahardyan

2. References Calvert, S., Englund, H.M, Handbook of Air Pollution Technology, Willey-Interscience Publication, (Chapter 9) Peavy, H.S., Rowe, D.R, Tchobanoglous, G., 1985, Environmental Engineering- International Edition, McGrawHill, Singapore (Chapter 9)

3. Control of Particulate Contaminants Control of Gaseous Contaminant

4. Control of Particulate Contaminants Gravitation Settling Chamber Centrifugal Collector Wet Collectors Fabric Filters (Baghouse filters) Electrostatic Precipitation (ESP)

5. Control of Gaseous Contaminant Adsorption Absorption Condensation Combustion

6. Control of Gases By Chemical Reaction NOx control – Ammonia Injection (Non Catalitic) NO + NH3+1/4 O2  N2 + 3/2 H2O NH3 + 5/4 O2  NO + ½ H2O Temperatures ranging 1070-1270 K – Selection Catalitic Reduction SCR 2NH3+2NO+1/2O2  2N2+3H2O (3) 2NH3+NO2+1/2O2  3/2N2 +3H2O (4) Efficiency (3) almost 95%. (4) 80-90%, emission NH3 20 ppm Temperature 570-720 K – Non selective catalitic reduction (NCR) H2, CO or HC – Electronic Beam Irradiation

7. Control of Gases By Chemical Reaction SOx – CuO/CuSO4 process Acceptance CuO+1/2O2+SO2  CuSO4 2NO+2NH3+1/2O2  2N2+3H2O Regeneration CuSO4+2H2  Cu+SO2+2H2O Cu+1/2O2  CuO

8. – Coal/limestone fuel mixtures CaCO3+1/2O2+SO2  CaSO4 + CO2 Ca : S ratio of 3 : 5  70% sulphurs removal (laboratory) actual + 50% – Dry sorbent injection 2NaHCO3+SO3  Na2SO3+2CO2+H2O Na2CO3+SO2  Na2SO3+CO2

10. Determining the solvent requirement in an absorption tower. An absorption tower is to be used to remove SO2 from the stack gas of a coal-fired furnace. The flow rate of the stack gas, measured at 1 atm pressure and 25oC, is 10 m3/s and the SO2 content is 3 percent by volume. Removal of 90% of the SO2 is required and water initially pure with the respect of SO2 is to be used as the liquid solvent. The equilibrium line for SO2 and water can be estimated by y = 30 x. Determine the flow rate of water that represents 150 percent of the minimum liquid requirement.

11. The gas flow (G’ + ammonia) is 50 kg-mol/h and is 10 percent by volume ammonia. Water that is initally pure with respect to ammonia is used as the solvent. Determine the water flow rate that is 1.3 times the minimum required to remove 96 percent of ammonia.

12. 450 kg/hour of a mixture of ethyl-methyl – ketone (butanone) in air (1.5 mol percent) is to be passed through a countercurrent absorber. The equilbirium equation for butanone in water is y = 2,5 x. Assume that the gas and water do not react chemically. What is the minimum flow of water-free butanone that must be used to absorb 95% percent of butanone?.

14. A well water is to be softened by split-flow ion exchange with the exchanger on the sodium cycle. The flow is 3.2 l/s, the hardness is 225 mg/L as CaCO3, the desired hardness is 50 mg/L CaCO3, and the moisture content of the resin is 45 percent. A test column has been used in thelaboratory to obtain a breakthrough curve. The computed hardness removed by the resin at the allowable breakthrough concentration Ca=0,05 Co was 282 meq/100 g resin on a dry weight basis. Determine the kilograms of resin required if the allowable breakthrough is 7 days.

15. A well water is to be softened by split flow ion exange with the exchanger resin on the sodium cycle. The flow is 2.56 l/s. The hardness is 195 mg/l as CaCO3. The desired hardness is 50 mg/l as CaCO3, the resin removes 296 meq/100 gram on a dry basis at an allowable breaktrough of 5% Co, and moisture content is 45 %. The allowable breakthrough time is seven days. Determine the weight of resin required on both moist and dry basis

16. An industrial wastewater with 107 mg/L of Cu2+ (3.37 meq/L) is to be treated by an exchange column. The allowable effluent concentration is 5 percent Co. A bereakthrough curve has been obtained from anexpereimental laboratory column on the sodium cycle. Determine the k value of the column.

17. Data concerning the column are : inside diameter 1,25 cm, length = 45 cm masss of resin = 41,5 g on moist basis (23.24 g on dry basis), moisture = 44%, bulk density 20 kg/ft3 and liquid flow rate = 1,0428 l/day. The design will have flowrate of 100,000 gal/day, the allowable breakthrough time is seven days of flow, and the resin depth is approximately two timesthe column diameter. Using the kinetic approach to column design determine: 1. resin required 2. the diameter and depth 3. the height of sorption zone