1. Refineries Emit a Wide Variety of Pollutants

3. ► Criteria Air Pollutants (CAP)
► Sulfur dioxide SO2
► Oxides of Nitrogen NOX
► Carbon Monoxide CO
► Particulate Matter (PM)
► Volatile Organic Compounds (VOC)
► Organic compounds that are
photochemically reactive

4. ► Hazardous Air Pollutants (HAP)
► Carcinogenic HAP, including benzene,
naphthalene,1,3-butadiene, Polycyclic
aromatic hydrocarbons (PAH)
► Non-carcinogenic HAP, including
Hydrogen Fluoride (HF) and Hydrogen Cyanide
(HCN)
► Persistent bio-accumulative HAP,
including mercury
► Other Pollutants
► Greenhouse Gases (GHG)
► Hydrogen Sulfide (H2S)

5. Properties of air pollutants
1-Particulate Matter
2-Nitrogen Oxides
3-Sulfur Oxides
4-Carbon monoxide (CO)
5-Ground-Level Ozone
6-Hydrocarbons

6. 1-Particulate Matter:
Airborne particulate matter, which includes
dust, dirt, soot, smoke, and liquid droplets
emitted into the air, is small enough to be
suspended in the Atmosphere.
Airborne particulates may be a complex
mixture of organic and inorganic
substances.

7.  They can be characterized by their physical
attributes,which influence their transport and
deposition, and their chemical composition, which
influences their effect on health.
 The physical attributes of airborne particulates
include mass concentration and size distribution.
 Ambient levels of mass concentration are measured
in micrograms per cubic meter (μg/m3).
 Particulate matter (PM) exceeding 2.5 microns (μm is
generally defined as coarse particles, while particles
smaller than 2.5 microns (PM2.5) are called fine
particles.

8. Sources of Particulates:
 Some particulates come from natural sources such
as evaporated sea spray, windborne pollen, dust, and
volcanic or other geothermal eruptions. Particulates
from natural sources tend to be coarse.
 Almost all fine particulates are generated as a result of
combustion processes, including the burning
of fossil fuels for steam generation, heating and
household cooking, agricultural field burning, diesel-
fueled engine combustion, and various industrial
processes.
 The largest stationary sources of particulate emissions
include fossil-fuel-based thermal power plants,
metallurgical processes, and cement manufacturing.

9. 2- Nitrogen Oxides:
 Nitrogen oxides (NOx) in the ambient air consist
primarily of nitric oxide (NO) and nitrogen dioxide
(NO2). These two forms of gaseous nitrogen oxides
are significant pollutants of the lower atmosphere.
Another form, nitrous oxide (N2O), is a greenhouse
gas.
 nitric oxide, a colorless, tasteless gas, is the
predominant form of nitrogen oxide. Nitric oxide is
readily converted to the much more harmful
nitrogen dioxide by chemical reaction with ozone
present in the atmosphere. Nitrogen dioxide is a
yellowish-orange to reddish-brown gas with a
pungent, irritating odor, and it is a strong oxidant. A
portion of nitrogen dioxide in the atmosphere is
converted to nitric acid (HNO3) and ammonium
salts.

12. Major Sources:
 Only about 10% of all NOx emissions come from
anthropogenic sources (Godish 1991). The rest
is produced naturally by anaerobic biological
processes in soil and water, by lightning and
volcanic activity, and by photochemical
destruction of nitrogen compounds in the upper
atmosphere. About 50% of emissions from
anthropogenic sources comes from fossil-fuel-
fired heat and electricity generating plants and
slightly less from motor vehicles.

13.  Other sources include industrial boilers,
incinerators, the manufacture of nitric acid and
other nitrogenous chemicals, electric arc
welding processes, the use of explosives in
mining, and farm silos. Worldwide annual
emissions of anthropogenic nitrogen oxides
are estimated at approximately 50 million
metric tons (World Resources Institute 1994).
The United States generates about 20 million
metric tons of nitrogen oxides per year, about
40% of which is emitted from mobile sources.

14. Effects on Ecosystems:
 Nitrogen oxides are precursors of both acid
precipitation and ozone, each of which is
blamed for injury to plants.
 While nitric acid is responsible for only a
smaller part of hydrogen ion (H+)
concentration in wet and dry acid
depositions, the contribution of nitrogen
oxide emissions to acid deposition could be
more significant.
 It is nitrogen oxide that absorbs sunlight,
initiating the photochemical processes that
produce nitric acid.

15.  Approximately 90–95% of the nitrogen oxides
emitted from power plants is nitric oxide; this
slowly converts to nitrogen dioxide in the
presence of ozone.
 The extent and severity of the damage
attributable to acid depositions is difficult to
estimate, since impacts vary according to soil
type, plant species, atmospheric conditions,
insect populations, and other factors that are
not well understood.

16. 3-Sulfur Oxides:
 Sulfur oxides (SOx) are compounds of sulfur
and oxygen molecules. Sulfur dioxide (SO2)
is the predominant form found in the lower
atmosphere. It is a colorless gas that can be
detected by taste and smell in the range of
1,000 to 3,000 micrograms per cubic meter
(μg/m3). At concentrations of 10,000 μg/m3,
it has a pungent, unpleasant odor.

17.  Sulfur dioxide dissolves readily in water
present in the atmosphere to form sulfurous
acid (H2SO3). About Sulfur trioxide (SO3),
another oxide of sulfur, is either emitted
directly into the atmosphere or produced
from sulfur dioxide and is rapidly converted
to sulfuric acid (H2SO4).

18. Major Sources:
 Most sulfur dioxide is produced by burning fuels
containing sulfur or by roasting metal sulfide ores,
although there are natural sources of sulfur
dioxide (accounting for 35–-65% of total sulfur
dioxide emissions) such as volcanoes. Thermal
power plants burning high-sulfur coal or heating oil
are generally the main sources of anthropogenic
sulfur dioxide emissions worldwide, followed by
industrial boilers and nonferrous metal smelters.
 Emissions from domestic coal burning and from
vehicles can also contribute to high local ambient
concentrations of sulfur dioxide.

19. 4-Carbon monoxide (CO):
 A colorless, odorless, poisonous gas produced by
incomplete fossil fuel combustion.
 Carbon monoxide interferes with the blood’s
ability to carry oxygen from the lungs to the
body’s organs and tissues. When inhaled, it
readily binds to hemoglobin in the bloodstream to
form carboxy hemoglobin (COHb) Hemoglobin ,
in fact ,has a much greater affinity for carbon
monoxide than it does for oxygen , so even small
amount of CO an seriously reduce the carrying
less oxygen , brain function is affected and heat
rate increases in an attempt to offset the oxygen
deficit.

21. 5-Ground-Level Ozone:
 Ozone (O3) is a colorless, reactive oxidant gas that is
a major constituent of atmospheric smog.
 Ground level ozone is formed in the air by the
photochemical reaction of sunlight and nitrogen
oxides (NOx), facilitated by a variety of volatile
organic compounds (VOCs), which are
photochemically reactive hydrocarbons.
 Ozone may be formed by the reaction of NOx and
VOCs under the influence of sunlight hundreds of
kilometers from the source of emissions.
 Ozone concentrations are influenced by the intensity
of solar radiation, the absolute concentrations of NOx
and VOCs, and the ratio of NOx and VOCs.

22. Health Impacts of Exposure:
 The main health concern of exposure to
ambient ground-level ozone is its effect on the
respiratory system, especially on lung function
several factors influence these health impacts,
including the concentrations of ground-level
ozone in the atmosphere, the duration of
exposure and average volume of air breathed
per minute.
 Most of the evidence on the health impacts of
ground-level ozone comes from animal studies
and controlled clinical studies of humans
focusing on short-term acute exposure.

23.  Clinical studies have documented an
association between short-term exposure to
ground-level ozone at concentrations of 200–
500 μg/m3 and mild temporary eye and
respiratory irritation as indicated by symptoms
such as cough, throat dryness, eye and chest
discomfort, thoracic pain, and headache.

24. 6-hydrocarbons

26. Air Pollution In Refinery Processes

27.  Sources of environmental pollution from the
petroleum industry:
 Air emissions from the petroleum industry
can be classified as combustion emissions,
fugitive emissions, emissions from storage
and handling of petroleum liquids and
secondary emissions.
 Combustion emissions are produced with the
onsite burning of fuels usually for energy
production and transmission purposes.

28.  Flaring is a specific source of combustion
emissions in the petroleum industry.
 Fugitive emissions (equipment leak
emissions) are released through leaking
valves, pumps, or other process devices.
 Storage and handling emissions are
contributed from the storage of natural gas
and crude oil, as well as their intermediate
and finished derivatives.
 The water systems of a production or
processing site (tanks, ponds, sewer system
drains, etc...) are the main source of
secondary emissions.

29. Sources and control of hydrocarbon
emissions
 The primary sources of hydrocarbon
emissions are leaks from piping system
components, evaporation from product
loading, losses from atmospheric storage
tanks and evaporation from wastewater
 collection and treatment. The relative
emission quantities from these sources might
appear as provided in Table 2.

32. The Petroleum Refinery Sector(IN USA)
► 150 domestic refineries
► 17 MMbbls/day crude throughput,
~20% of world crude production
► Refineries have hundreds
of emission points
► Second largest industrial
source of GHGs

33. LEAK DETECTION

35. STORAGE TANKS

36. VAPOR RECOVERY

37. VAPOR DESTRUCTION

39. Refinery Process
Units

40. Crude Desalting:
► Contaminants in crude oil can cause corrosion
of equipment and processing problems
► Crude oil is washed with water
► Water is separated and now contains
contaminants
► Largest source of wastewater at the refinery
► Largest source of benzene in wastewater
► Air emissions
► Benzene, VOC, other air toxics
► Control Technology: Steam stripper/Bio-treatment

42. Catalytic Reforming:
► Converts naphtha-boiling range molecules into
higher octane reformate
► Produces hydrogen as a byproduct that can be
used in Hydro-treaters or the hydrocracker
Uses catalysts that can be regenerated
► Air emissions
► CAP (CO, Nox), HAP (benzene, toluene, xylene,
naphthalene),VOC, dioxins
► Control Technology: Scrubber

43. Fluid Catalytic Cracking
► Upgrades heavier fractions into lighter, more valuable products
► Feed stocks
► Gas oils (from vacuum & atmospheric distillation, Coker)
► Vacuum tower bottoms
► Uses a fluidized catalyst to contact the feedstock at high
temperature and
moderate pressure to vaporize long chain molecules and break
them into
shorter molecules
► Largest source of emissions of SO2, NOx, CO, PM, and metals
at the refinery
► Air emissions
► CAP (SO2, NOx, CO, PM), HAP (metals, ammonia), VOC
► Control Technology: Scrubber, ESP

44. Sulfur Recovery:
H2S removal and recovery using an amine
treating unit and the Claus process
► Air emissions
► CAP (SO2, NOx, CO), HAP (carbonyl sulfide,
carbon disulfide)
► Control Technology: Scrubber

46. Thermal Processing:
► Converts heavy fractions into lighter
products
► Types
► Delayed coking
► Fluid coking (no emissions)
► Vis-breaking (no emissions)
► Flexi-coking (no emissions)
► Air emissions
► Delayed coking unit emits CAP (SO2, NOx,
PM), HAP (metals), VOC
► Control Technology: Flares

47.  Delayed Coking Unit

48. ► Heavy residues are thermally cracked in a
furnace with multiple parallel passes (semi-batch
process), which cracks the heavy, long chain
hydrocarbon molecules into gas oil and
petroleum coke
► Air emissions
► Steam vents
► Coke drill
► Coke pit

49. Refinery Process Unit
Controls

50. Flares:
► Combustion control device used to burn waste
gases in both normal and process upset conditions

51. Scrubbers
► Removal of material from
the gas phase to the liquid
phase
► SO2 removal from stack
gases
► removal of organics from
vent gases

52. Steam Strippers
► A distillation process
whereby gases and other
unwanted organics are
removed from water
► Benzene removal from
wastewater
► removal of other organics
from water

53. Electrostatic Precipitators
(ESP)
► PM control device
that uses an induced
electrostatic charge to
remove small
particles from gases
(similar to static
electricity)