Colorado School of Mines Pollution Prevention Fugitive Emissions

2

3

4

5 Unintentional releases, such as those due to leaking equipment, are known as fugitive emissions Unintentional releases, such as those due to leaking equipment, are known as fugitive emissions Can originate at any place where equipment leaks may occur Can originate at any place where equipment leaks may occur Can also arise from evaporation of hazardous compounds from open topped tanks Can also arise from evaporation of hazardous compounds from open topped tanks

6 Fugitive Emissions Sources Pumps and Valves TanksMeasurementCalculationPrevention

7 Sources of Fugitive Emissions

8 Sources of Fugitive Emissions Pumps and Valves 70% of process plant fugitive emissions are from pumps and valves 70% of process plant fugitive emissions are from pumps and valves Measurement of fugitive emissions will require some level of knowledge of pumps and valves Measurement of fugitive emissions will require some level of knowledge of pumps and valves

9 Sources of Fugitive Emissions Pump Packing

10 Sources of Fugitive Emissions Centrifugal Pump

11 Sources of Fugitive Emissions Pump and Motor Assembly

12 Sources of Fugitive Emissions Pumps and Flanges

13 Sources of Fugitive Emissions Gate Valve

14 Sources of Fugitive Emissions Globe Valve

15 Sources of Fugitive Emissions Gate Valve

16 Sources of Fugitive Emissions Globe Valve

17 Sources Check Valve

18 Sources: Butterfly Valves

19 Sources of Fugitive Emissions Flanges

20 Sources of Fugitive Emissions Flanges

Piping Systems One line diagrams One line diagrams Valves Pumps Pipes 21

Tanks 22

Tanks 23

Tanks 24

Tanks Fugitive Emissions Tanks are designed to reduce fugitive emissions Tanks are designed to reduce fugitive emissions Floating roof tanks are typically used for very large diameter tanks where a fixed roof construction becomes expensive to support and for products where vapor emissions become an issue Floating roof tanks are typically used for very large diameter tanks where a fixed roof construction becomes expensive to support and for products where vapor emissions become an issue 25

26 Fugitive Emissions from Storage Tanks There are six basic tank designs Fixed roof Fixed roof vertical or horizontal vertical or horizontal least expensive least expensive least acceptable for storing liquids least acceptable for storing liquids emission are caused by changes in emission are caused by changes in temperature temperature pressure pressure liquid level liquid level

27 Fugitive Emissions from Storage Tanks External floating roof External floating roof open-topped cylindrical steel shell open-topped cylindrical steel shell steel plate roof that floats on the surface of the liquid steel plate roof that floats on the surface of the liquid emission limited to evaporation losses from emission limited to evaporation losses from an imperfect rim seal system an imperfect rim seal system fittings in the floating deck fittings in the floating deck any exposed liquid on the tank wall when liquid is withdrawn and the roof lowers any exposed liquid on the tank wall when liquid is withdrawn and the roof lowers Domed external floating roof Domed external floating roof similar to internal floating roof tank similar to internal floating roof tank existing floated roof tank retrofitted with a fixed roof to block winds and minimize evaporative loses existing floated roof tank retrofitted with a fixed roof to block winds and minimize evaporative loses

28 External Floating Roof Tanks

29 Fugitive Emissions from Storage Tanks Internal floating roof Internal floating roof permanent fixed roof with a floating roof inside permanent fixed roof with a floating roof inside evaporative losses from evaporative losses from deck fittings deck fittings non-welded deck seams non-welded deck seams annular space between floating deck and the wall annular space between floating deck and the wall

30 Fugitive Emissions from Storage Tanks Variable vapor space Variable vapor space expandable vapor reservoirs to accommodate volume fluctuations due to: expandable vapor reservoirs to accommodate volume fluctuations due to: temperature temperature barometric pressure changes barometric pressure changes uses a flexible diaphragm membrane to provide expandable volume uses a flexible diaphragm membrane to provide expandable volume losses are limited to: losses are limited to: tank filling times when vapor displaced by liquid exceeds tank’s storage capacity tank filling times when vapor displaced by liquid exceeds tank’s storage capacity

Measuring Fugitive Emissions Instruments Portable gas detector Portable gas detector Catalytic bead Catalytic bead Non-dispersive infrared Non-dispersive infrared Photo-ionization detectors Photo-ionization detectors Combustion analyzers Combustion analyzers Standard GC with flame ionization detector is most commonly used Standard GC with flame ionization detector is most commonly used 31

32 Measuring Fugitive Emissions Approach Average emission factor approach Average emission factor approach Screening ranges approach Screening ranges approach EPA correlation approach EPA correlation approach Unit-specific correlation approach Unit-specific correlation approach

Measuring Fugitive Emissions What factors can impact fugitive emission measurement? What factors can impact fugitive emission measurement? 33

34 Average Emission Factor Approach E TOC = TOC emission rate from a component (kg/hr) F A = applicable average emission factor for the component (kg/hr) WF TOC = average mass fraction of TOC in the stream serviced by the component

35 Screening Ranges Approach Leak/ No-leak approach Leak/ No-leak approach more exact than the average emissions approach more exact than the average emissions approach relies on screening data from the facility, rather than on industry wide averages relies on screening data from the facility, rather than on industry wide averages

36 EPA Correlation Approach Predicts mass emission rates as a function of screening values for a particular equipment type Predicts mass emission rates as a function of screening values for a particular equipment type Total fugitive emissions = sum of the emissions associated with each of the screening values Total fugitive emissions = sum of the emissions associated with each of the screening values Default-zero leak rate is the mass emission rate associated with a screening value of zero Default-zero leak rate is the mass emission rate associated with a screening value of zero

37 EPA Correlation Approach

38 Unit-Specific Correlation Approach Most exact, but most expensive method Most exact, but most expensive method Screening values and corresponding mass emissions data are collected for a statistically significant number of units Screening values and corresponding mass emissions data are collected for a statistically significant number of units A minimum number of leak rate measurements and screening value pairs must be obtained to develop the correlations A minimum number of leak rate measurements and screening value pairs must be obtained to develop the correlations

39 Controlling Fugitive Emissions Modifying or replacing existing equipment Modifying or replacing existing equipment Implementing a leak detection and repair (LDAR) program Implementing a leak detection and repair (LDAR) program

40 Equipment Modification

41 Equipment Modification Magnetic Drive Pump

42 LDAR Programs Designed to identify pieces of equipment that are emitting sufficient amounts of material to warrant reduction of emissions through repair Designed to identify pieces of equipment that are emitting sufficient amounts of material to warrant reduction of emissions through repair Best applied to equipment types that can be repaired on-line or to equipment for which equipment modification is not suitable Best applied to equipment types that can be repaired on-line or to equipment for which equipment modification is not suitable

43 Emissions Estimation from Storage Tanks L T = total losses, kg/yr L S = standing storage losses, kg/yr L W = working losses, kg/yr The standing storage losses are due to breathing of the vapors above the liquid in the storage tank V V = vapor space volume, m 3 W V = vapor density, kg/m 3 K E = vapor space expansion factor, dimensionless K S = vented space saturation factor, dimensionless 365 = days/year M V = vapor molecular weight R = universal gas constant, mm Hg-L/ E K- mol P VA = vapor pressure at daily average liquid surface temperature, T LA = daily average liquid surface temperature, E K ) T V = daily temperature range, E K ) P V = daily pressure range, ) P B = breather vent pressure setting range, P A = atmospheric pressure,

44 Emissions Estimation from Storage Tanks H VO =vapor space outage, ft = height of a cylinder of tank diameter, D, whose volume is equivalent to the vapor space volume of the tank Q = annual net throughput (tank capacity (bbl) times annual turnover rate), bbl/yr K N = turnover factor, dimensionless for turnovers > 36/year, K N = (180 + N)/6N for turnovers # 36, K N = 1 where N = number of tank volume turnovers per year K P = working loss product factor, dimensionless for crude oils = 0.75 for all other liquids = 1.0

45 Fugitive Emissions from Waste, Treatment and Disposal I = importantS = secondaryN = negligible or not applicable Surface Wastewater treatment plants Land Pathway impoundmentsAerated Non-aerated treatmentLandfill VolatilizationI II I I BiodegradationI II I S Photodecomp.S NN N N HydrolysisS SS N N Oxidation/red’nN NN N N AdsorptionN SS N N Hydroxyl radicalN NN N N