Mercury Emissions fromCrude Oil & Natural Gas &

Mercury Removal

Table of Contents1. Introduction......................................................1

1.1. Mercury in Natural Gas.......................................1

1.2. Levels of mercury in natural gas.............................11.3. Mercury in Crude Oil.........................................1

2. Permissible Limit of Mercury....................................13. Hazardous Effects caused by mercury............................1

3.1. Elemental mercury effects....................................13.2. Effects of other mercury compounds (inorganic and organic)...1

3.3. Environmental Effects........................................13.4. Hazardous Effects caused by methyl mercury...................1

3.5. Impacts of Mercury on gas processing operations:.............14. Mercury Emissions from Oil and Natural Gas.....................1

4.1. Mercury Emissions to Water...................................14.2. Refinery Wastewater..........................................1

4.3. Mercury Emissions to Air.....................................14.4. Mercury Streams Emissions via Solid Waste....................1

5. Mercury Removal Process Options.................................15.1. Regenerative adsorbents for mercury removal..................1

5.2. Non-regenerative adsorbents for mercury removal..............15.2.1. Liquids carry-over onto sulphur-impregnated activated carbon

15.2.2. Reclaiming mercury from spent adsorbents Activated carbon. .1

5.2.3. Metal sulphides............................................16. Mercury Waste Treatment and Recovery Methods....................1

6.1. Environmental Management of Mercury Wastes...................16.2. Environmental Management of Mercury Wastes Disposal Operation 1

6.3. Environmental Management of Mercury Treatment Methodology....1

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7. Conclusion......................................................18. Recommendations...................................................1

9. Glossary..........................................................110. References......................................................1

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Mercury Emissions from CrudeOil & Natural Gas & MercuryRemoval techniques

1.IntroductionMercury is a heavy, silvery-white metal. As compared to other

metals, it is a poor conductor of heat, but a fair conductor of

electricity. Mercury has a freezing point of −38.83°C and a

boiling point of 356.73°C, both exceptionally low for a metal,

and it is the only elemental metal known to melt at a generally

cold temperature. Mercury is a trace component of all geologic

hydrocarbons. Its origin relative to the origin of the oil and

gas in which it is found, and the geological reasons for its

occurrence in the various types of fossil fuels are largely

unexplored topics.

Methyl mercury is a much more toxic compound that forms when

mercury binds with organic molecules in the environment. This

usually happens when mercury is released into the atmosphere

through burning and settles into wetlands or streams, where it

can be taken up by aquatic life.

1.1. Mercury in Natural Gas Mercury in most forms (species) is toxic and contributes to

health, safety, and environmental risks. In natural gas, mercury

occurs as the metallic form (species). Various forms of mercury—

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elemental, organometallic, and inorganic salt— can be present in

natural gas condensates, depending on the origin of the

condensates. Knowledge of the different species and total mercury

content in condensates is important, because the damage caused to

industrial facilities, particularly petrochemical plants, by the

presence of mercury can be financially crippling.

In 1973, recognition of the effects of mercury in natural gas

occurred when a catastrophic failure of aluminum heat exchangers

occurred at the Skikda LNG plant in Algeria (Spiric 2001). [1]

1.2. Levels of mercury in natural gas Different areas of the world have varying levels of mercury in

their natural gas reservoirs. Figure 2 shows average mercury

levels that have been reported to UOP. In recent years, mercury

levels have increased from typical highs of 30 or 40 ug/Nm3 to

levels exceeding 1000 ug/Nm3 in the Pacific Rim area. With a

greater understanding of levels in specific geographical areas

has come a greater level of expectation in terms of what is

required to remove mercury both on- and off-shore in a variety of

locations worldwide.

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1.3. Mercury in Crude Oil Crude oil contains both dissolved and suspended mercury compounds

and, although analysis for total mercury in crude oil yields the

sum of both forms, the concentration of suspended forms that is

obtained from sampling crude oil is highly dependent on the

location that samples are taken in the production and refining

process. Furthermore, given that the fates of suspended forms

(HgS) and dissolved forms are different, the concentration of

each is important to predicting the fate of mercury in a

refinery.

Mercury in crude oil has received more scrutiny as refineries

seek “cleaner” oil for their product streams. Among the problems

cited are: excessive levels of mercury in wastewater streams,

preventing discharge in open rivers or oceans; mercury

contamination of products generated from the refinery streams,

such as gas streams, liquefied petroleum gas, and light or heavy5 | P a g e

distillate products; hydro treating catalyst poisoning or

contamination in refined streams because of metal amalgamation;

corrosion of equipment because of metal embrittlement; and

additional expenses in upstream and downstream facilities because

of special disposal requirements for contaminated mud from tanks,

cleaning of equipment and ships, and restricted product shipping

alternatives.

Fig: 1 Types of mercury associated with hydrocarbon streams

2. Permissible Limit of MercuryPakistan’s Scenario

Municipal and Liquid Industrial Effluents 0.01 mg/1

Industrial Gaseous Emissions 10 mg/nm3

In Drinking Water < 0.001mg/l

3.Hazardous Effects caused by mercury

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Mercury is one of the major toxic elements found in waste from

oil and gas industries. It is available in all forms. Due to its

abundant availability, it has a wide range of environmental and

health impacts. Once disposed into atmosphere, it starts

transforming continuously into various other forms. It also moves

upward in food chain causing various health hazards. Mercury is

naturally occurring metal, which has several forms. Under normal

condition of temperature and pressure, it exists in liquid form,

When heated it can be transferred to gaseous state. In

combination with other elements it is available in inorganic and

organic form. Organic mercury (methyl mercury) is most dangerous

compound that is of great concern for the present situation. The

most important factor to be considered is that it can be re-

emitted into atmosphere once it is deposited in earth surface.

When mercury enters into the atmosphere, it starts to get

transformed into another form. Metallic mercury once deposited in

bottom of water bodies can be remobilized and introduced into

aquatic cycle through physical, chemical process, and largely

through microbial process. When uptake of a toxic metal occurs,

microorganisms are frequently able to perform detoxification,

yielding a product that can be more toxic to higher organisms.

This is particularly true in the bacterial production of methyl

mercury, a compound 1000 times more toxic to man than metallic

mercury.

3.1. Elemental mercury effects

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Elemental (metallic) mercury primarily causes health effects when

it is breathed as a vapor where it can be absorbed through the

lungs. These exposures can occur when elemental mercury is

spilled or products that contain elemental mercury break and

expose mercury to the air, particularly in warm or poorly-

ventilated indoor spaces. Symptoms include these: tremors;

emotional changes (e.g., mood swings, irritability, nervousness,

excessive shyness); insomnia; neuromuscular changes (such as

weakness, muscle atrophy, twitching); headaches; disturbances in

sensations; changes in nerve responses; performance deficits on

tests of cognitive function. At higher exposures there may be

kidney effects, respiratory failure and death. People concerned

about their exposure to elemental mercury should consult their

physician.

3.2. Effects of other mercury compounds (inorganic and

organic)High exposures to inorganic mercury may result in damage to the

gastrointestinal tract, the nervous system, and the kidneys. Both

inorganic and organic mercury compounds are absorbed through the

gastrointestinal tract and affect other systems via this route.

However, organic mercury compounds are more readily absorbed via

ingestion than inorganic mercury compounds.

Symptoms of high exposures to inorganic mercury include: skin

rashes and dermatitis; mood swings; memory loss; mental

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disturbances; and muscle weakness. People concerned about their

exposure to inorganic mercury should consult their physician.

3.3. Environmental Effects

3.3.1. Fate and Transport and Ecological Effects of Mercury

Mercury in the air may settle into water bodies and affect water

quality. This airborne mercury can fall to the ground in

raindrops, in dust, or simply due to gravity (known as “air

deposition”). After the mercury falls, it can end up in streams,

lakes, or estuaries, where it can be transferred to methyl

mercury through microbial activity. Methyl mercury accumulates in

fish at levels that may harm the fish and the other animals that

eat them. Mercury deposition in a given area depends on mercury

emitted from local, regional, national, and international

sources. The amount of methyl mercury in fish in different water

bodies is a function of a number of factors, including the amount

of mercury deposited from the atmosphere, local non-air releases

of mercury, naturally occurring mercury in soils, the physical,

biological, and chemical properties of different water bodies and

the age, size and types of food the fish eats. This explains why

fish from lakes with similar local sources of methyl mercury can

have significantly different methyl mercury concentrations.

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3.4. Hazardous Effects caused by methyl mercuryMethyl mercury easily gets into tissues of the plants and

animals. For decade, large amounts of mercury were directly

discharged into lakes and rivers. Local discharges led to high

mercury concentrations in fish. Compared to mercury, methyl-

mercury is more easily absorbed by fish and other aquatic fauna,

either directly through the gills or by ingesting of contaminated

aquatic plants and animals. This could further move to human and

other animals through food chain causing various physical and

disorder. Several end points, including late walking, late

talking, nervous system dysfunctioning, and delayed mental

development can be seen in children who are exposed to high level

of methyl mercury. Impact on central nervous system, reproduction

system, immune system, genotoxic effects are some of the impacts

of methyl mercury toxicity. High levels of methyl mercury

exposure can cause debilitating nervous system damage and

eventually lead to coma and death. Because methyl mercury readily

crosses the placenta, fetuses can have levels 30 times higher

than their mothers. The Food and Drug Administration says its

methyl mercury standard for fish of 1 part per million is 10

times lower than the level at which toxic effects - numbness in

the arms and legs, slurred speech and difficulty in walking - are

readily observed in adults.

The Environmental Protection Agency has a standard of mercury

exposure that is four times stricter than FDA's limit. The

National Academy of Sciences, a federal round table of eminent

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scientists, has endorsed the EPA standard, saying that even low

levels of methyl mercury exposure can cause neurological defects

in the fetus and lead to heart disease in adults.

3.5. Impacts of Mercury on gas processing operations:Mercury was found to produce several impacts on gas processing

operations. They include;

Mercury deposits in cryogenic fractionation equipment

causing cracking of welds in the headers of aluminum

exchangers. Mercury readily wets most surfaces and forms

amalgams with a number of metals. A particular concern is

aluminium, because it is widely used in cryogenic heat

exchangers. This is a potentially reactive metal protected

from attack by air and water by an oxide layer. If the

protective oxide layer is damaged (say, by a small scratch)

and liquid mercury is present, an amalgam is formed, which

will allow rapid reaction with air or water:

Hg + Al → Hg(Al)

Hg(Al) + 6H2O → Al2O3.3H2O + H2 + Hg

Mercury contaminates gas treatment processes such as

molecular sieve and glycol dehydration units, chloride

removal systems, and acid gas removal systems.

Mercury sorbent materials, when spent, constitute a

generated hazardous waste that plant operators must store or

process for disposal.

Mercury poisons catalysts in ethylene, aromatics and olefins

manufacture.11 | P a g e

Mercury contaminations of equipment pose.

4. Mercury Emissions from Oil and Natural Gas

Production and Processing

Mercury in produced hydrocarbons may escape to the environment by

several avenues of egress. These avenues may be generally

categorized as wastewater, solid waste streams and air emissions.

Waste waters originate in production operations in the form of

produced water and in refining and gas processing as wastewater.

Solid waste streams are generated in production, transportation

and in refining. Air emissions originate from fugitive emissions

from process equipment and from combustion, with combustion

thought to be vastly dominant as a possible avenue by which

mercury in oil and gas may be transferred from produced

hydrocarbons to the environment.

The industry distinguishes between upstream and downstream

operations. The upstream category refers to primary production

and whatever processing is necessary to place the produced fluids

in the transportation system. The term downstream operations

refer to refining and gas processing to produce salable products.

Natural gas is transported exclusively via pipeline while crude

oil is transported by a variety of ways with pipelines and

tankers conveying the overwhelming majority.

4.1. Mercury Emissions to WaterThe main wastewater streams that derive from petroleum production

and processing are produce d water from both oil and gas

12 | P a g e

production and refinery waste waters. Very minor amounts of water

(relative to produced water and refinery wastewater) derive from

gas processing and these are mainly water from separators at gas

plants (essentially produced waters) and condensed water from

dehydration. No wastewater streams originate from transportation

systems other than the very small amounts that come from pipeline

pigging operations and tanker ballast. The discussion that

follows will concentrate on the major streams as mercury in water

data are not reported for the minor sources.

4.1.1. Produced Water

Normal production operations of both crude oil and natural gas

involve primary separation of water, gas and oil. Separated water

(referred to as produced water when separated close to the well)

is either discharged (to an ocean, lake or stream or evaporation

pond) or re-injected (usually to the formation it came from).

Reinjection is utilized to enhance oil recovery (EOR) or to

comply with regulatory requirements stemming from environmental

concerns.

Only limited data are available concerning mercury in produced

waters and essentially none concerning Specification. Produced

waters may contain suspended HgS, elemental Hg0 and/or oxidized

forms but the relative amounts in any produced waters are not

reported relative to the forms that occur in co-produced

hydrocarbons. HgS and Hg0 are the dominant forms found in

produced water associated with gas production in the Gulf of

Thailand (Frankiewicz and Tussaneyakul 1997). [3]

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Gas condensates originating in the Gulf of Thailand contain

between 100 and 1000 ppb total mercury (mostly elemental). The

mercury species present in produced waters are unknown but likely

include higher percentages of suspended forms (HgS) and ionic

forms than the produced crude oil.

4.2. Refinery Wastewater Most of the mercury in refinery waste water is derived from crude

oil. In desalter applications, water is mixed with the crude to

scrub soluble chlorides. If chlorides were not removed, hydrogen

chloride could be formed downstream and lead to corrosion. Other

contaminates removed by the water are soluble mercury compounds,

inorganic salts, elemental mercury and other heavy metals.

The chemical compositions of refinery waste waters vary widely,

as do the volumes of water (per barrel of oil processed) produced

by refineries. Major water compositional differences stem from

process configuration (products produced) and from the type of

crude oil that is processed (high sulfur crude, sweet crude). The

wastewater that enters water treatment systems at refineries is a

composite of water discharges from individual processing units

that differ in type and function. Water streams from process

units are differentiated and categorized as waters that contact

hydrocarbons (including condensed steam from stripping) and

cooling waters that typically do not contact hydrocarbons

directly but may contain some hydrocarbon contamination from

leakage. Total mercury at up to 1 ppb, species unknown (Ruddy

1982) [4]. Specification of mercury in refinery wastewater is

14 | P a g e

largely unknown. Post-biological treatment waters from municipal

sewage treatment (similar in process to refinery biological water

treatment) generates mercury compound specification such that

less than 5 percent (of the total mercury concentration) exists

as monomethylmercury, less than 0.01 percent as dialkylmercury,

less than 0.1 percent as Hg0 , possibly 10-30 percent suspended

particulate Hg, less than 10 percent labile Hg(2+), and between

60 and 90 as organochelated Hg(2+). The concentration of total

mercury in effluents from (municipal) sewage treatment facilities

is in the range of 5-20 ng/L (Bloom and Falke 1996). [5] The mean

and range of mercury concentration in refinery wastewater cannot

be stated with certainty. Very little information is available in

the published literature that speaks directly to this issue. The

EPA study of refinery effluents from the early 80’s (Ruddy 1982)

provides a mean close to 1 ppb but the methodology to arrive at

this number is poorly documented.

4.3. Mercury Emissions to Air The primary opportunities for atmospheric emissions of mercury in

oil and gas production and processing operations are fuel

combustion, mercury in fugitive emissions and gas flares at

primary production operations.

The amount of mercury in such emissions is not known, a rough

estimate is possible. The distribution of mercury in oil to

vented gases can determined by Henry’s law. Henry’s constant for

mercury in oil is the solubility divided by the vapor pressure (2

ppm/25 mg/m3). The upper limit amount of mercury in 1 million

15 | P a g e

metric tons (1.5 billion m3 methane) would be no greater than

approximately 185 kg if the mean mercury in oil concentration is

10 ppb.

4.4. Mercury Streams Emissions via Solid Waste Under the Resource Conservation and Recovery Act (RCRA; 42 U.S.C.

321), materials containing mercury or mercury compounds are

regulated as hazardous solid waste if they meet the regulatory

definition of solid waste and the definition of hazardous waste.

The hazardous category is achieved if the material exhibits

either a defined characteristic or is specifically listed by EPA

as hazardous.

Solid wastes directly associated with exploration and crude oil

or natural gas production are exempted from regulation as

hazardous wastes. The exempted categories include drilling fluids

and other wastes directly related to production. For this reason,

such wastes are infrequently scrutinized for metals content and

data are scarce upon which one might estimate the totals for this

category.

Wastes are designated as characteristically hazardous based on

the concentration of mercury in waste leachate as determined by

the Toxicity Characteristic Leaching Procedure (TCLP). Refinery

solid waste streams are routinely examined using TCLP for metals

leachability characteristics and treated according to RCRA

requirements.

Filby and various colleagues (Shah, Filby and Haller 1970, Filby

and Shah 1975, Hitchon, Filby and Shah 1975, Hitchon and Filby

16 | P a g e

1983) [6] measured mercury in crude oils using neutron activation

analysis. This early work was directed to associating chemical

characteristics of crude oil with geologic origin for exploration

purposes.

Musa et al. (1995) [7] reported total mercury in Libyan crude oils

to be in the range of 0.1 to 12 ppb.

5. Mercury Removal Process Options The global market has a number of approaches for mercury removal.

These options can be categorized as regenerative adsorbents and

non- regenerative adsorbent solutions for mercury contaminant

removal.

5.1. Regenerative adsorbents for mercury removalThe protection of aluminium heat exchangers can be accomplished

using a layer of silver-containing molecular sieve inside the

dehydration vessels. The active silver forms an amalgam with the

mercury, and its zeolitic substrate adsorbs moisture in the gas

to be treated.

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Fig: 3 Generative Absorbent for Mercury Removal

5.2. Non-regenerative adsorbents for mercury removal There are two types of non-regenerative MRU: carbon systems and

metal sulphide beds. The common and traditional approach to

mercury removal has historically been through the use of sulphur-

impregnated carbon beds. Existing sulphur-impregnated activated

carbon options tend to be less effective at positions upstream of

molecular in the gas phase sieve drying systems or glycol

injection due to the risk of capillary condensation in the

position utilization micropores of the carbon sub-structure. The

pore size distribution of carbon products is such that this has

been problematic in the past, particularly where MRU locations

have been in the up-front position, where raw gas is often at or

close to its dew point and entrained liquids are common. This is18 | P a g e

where fixed-bed, metallic-based MRU products find greatest

success in their ability to treat “wet” gas streams in up-front

positions. Non-regenerative metal sulphides can successfully

remove mercury from raw gas, upstream of the amine unit and the

dehydration vessels. Utilizing larger MRU vessels, this approach

protects the brazed aluminum heat exchanger and ensures

significantly less mercury contamination in and around the

process plant. This option has become increasingly popular, since

it minimizes the total mercury present before there is any

opportunity for mercury to migrate to various locations within a

gas processing plant and avoids the risk of subsequent

partitioning into processed natural gas and condensate streams.[2] It also avoids subsequent adsorption onto any pipe asset or

piece of equipment downstream.

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Fig: 4 Non-Regenerative Absorbent for Mercury Removal

5.2.1. Liquids carry-over onto sulphur-impregnated activated carbon

The degree of liquid adsorbed onto carbon during the life of a

sulphur-impregnated carbon-based MRU is shown in Table 2.

Impact of liquids on mercury removal using activated

carbon

Bed

position

Total

volati

les

(200°C

),wt%

Total S,

wt% (dry

basis)

Total

Hg, wt%

(dry

basis)

Hg/S on

w/w

basis

Hg/S on

a molar

basis,%

% Sulphur

utilization

Layer 1 21.1 7.02 1.89 0.27 0.0429 4.29Layer 2 21.0 6.57 1.71 0.26 0.0414 4.14Layer 3 26.8 8.32 2.12 0.25 0.0406 4.06Layer 4 24.4 7.97 0.29 0.04 0.0057 0.57

The MRU can be shown in terms of total wt% volatiles

(200°C).Layer 1 represents carbon recovered from the inlet

portion of the bed, and layers 2, 3 and 4 represent subsequent

layers. Each layer was bagged upon discharge, following a

lifetime measured in months rather than years, as per design. The

total wt% of active sulphur was measured on each layer of

discharged carbon. While sulphur levels on newly installed

activated carbon are typically 10-18 wt%, the levels on the spent

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material were measured at 6-9 wt%. In order to measure the

mercury removal efficiency of sulphur-impregnated activated

carbon, the percentage of utilized sulphur was also

measured .This is where on a molar basis. The percentage of

sulphur utilized in the equilibrium section of the vessel (layers

1, 2 and 3) was measured at ~4 wt%. By comparison, on a dry

natural gas without the attendant issues of liquid entrainment,

this percentage utilization would be expected to be >>10 wt%. The

data confirm that sulphur-impregnated activated carbon is prone

to sulphur dissolution and micropore blocking when treating wet

gas.

The data also strongly suggest that the carbon has co-adsorbed a

significant quantity of liquid (20-30%) from the raw natural gas.

This contributed to its shortened service life.

5.2.2. Reclaiming mercury from spent adsorbents Activated carbon

After the carbon is discharged from an MRU, it is usually sent to

a specialized plant, where mercury is reclaimed via vacuum

distillation. There is no useful purpose for the remaining carbon

and it undergoes high-temperature incineration.

5.2.3. Metal sulphides Specialized processes are used for mercury reclaiming from metal

sulphides. For both carbon-based and metal sulphide-based

adsorbents, controls are in place to ship material

internationally from source (gas processing bagged upon

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discharge, following a lifetime meas- plant) to destination

(reclaim facility). The paperwork and experience required to

accomplish such transportation is complex and on each layer of

discharged carbon. While sulphur requires very careful

consideration.

6. Mercury Waste Treatment and Recovery Methods Mercury waste, once identified, must be treated prior to disposal

of residue or debris to avoid the long-term liabilities of burial

or storage. Hydrocarbon sludge is normally higher in mercury

content than the process fluid from which it was deposited. The

reason is that elemental and organic mercury has higher molecular

weight organic compounds. Moreover one technology is not

sufficient to completely treat mercury waste. Often a combination

of physical, chemical, immobilization, thermal, electrolytic and

in situ verification treatment methods need to be used.

Due to the presence hydrocarbon matrix in sludge, the sludge is

one of the more difficult waste materials to process for

treatment and disposal.

Mercury waste can be treated and disposed by,

1. Recovery / recycle / reuse

2. Physical / chemical treatment

3. Incineration

Recycling methods can be gravity separation, filtration,

distillation, solvent, chemical regeneration etc. Physical

methods could be neutralization, precipitation / separation and

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detoxification (chemical). In incineration, the waste is burnt at

medium / high temperatures.

Various researchers have conducted researches on treatment of

mercury laden waste and have found some success to reduce and

recovery mercury from the waste.

Thermal treatmentThermal process is considered as an alternative technology for the

treatment of mercury contaminated waste. Thermal treatment is

viewed as a distillation process at controlled Temperature and

reactor conditions, in which mercury vapor is condensed and

collected in relatively pure form. The normal practice for thermal

treatment is incineration and pyrolysis.

Table 3: Summary of mercury waste treatment and recovery by

thermal treatment method.

Origin andcharacteristics

of waste

Treatment methods Results

Soil contaminated

with high level

of mercury such

as in metering of

Natural gas

sites.

Prototype thermal

treatment process,

chemical leaching

process, combination of

physical separation

/Chemical leaching

process.

Chemical treatment combined

with physical separation

process is most effective.

Hazardous waste

of organic nature

Use of moderate

temperature for Thermal

treatment.

The method can handle soils

And dewatered sludge.

23 | P a g e

Mercury

contaminated

Waste

Pretreatment, volume

reduction and high

temperature oxidation

(10000C)

Good recovery with

decomposition of all

mercury Compounds.

Mercury

contaminated

Sludge.

Components: furnace,

heat exchanger, gas

purifier carbon, and

vacuum pump

99% pure mercury received

6.1. Environmental Management of Mercury Wastes Developing Inventory Of Mercury Containing Materials, Equipment

And Wastes

Conducting Environmental Surveys

Reduction of Mercury Emissions

Introduction of Alternatives

Encouraging Recovery, Reuse And Recycling of Mercury Materials

Enhancing Role of Environment Protection Agencies (EPA) For

Management of Mercury

Reduction In Mining of Mercury

Mercury Free Health Care Facilities

Mass Awareness Programmes

6.2. Environmental Management of Mercury Wastes Disposal Operation

Deposit into or on to land

o Mercury waste under uncontrolled waste mechanism

o Mercury waste mixed with other solid wastes

o Stabilized/solidified mercury waste

o Mercury contained in residue/ash of incineration

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Land treatment

Deep injection

Surface impoundment

Temporary storage

Long term storage of mercury waste

6.3. Environmental Management of Mercury Treatment Methodology

General Steps

Pre Treatment

Roast Treatment

Retort Treatment

Additional Treatment Technologies

o Chemical Oxidation

o Chemical Leaching

o Ion Exchange

o Amalgamation

Land Filling

7. ConclusionMercury is a trace contaminant in crude oil and petroleum

products in the part per billion levels.

It can be encountered in a variety of forms and vary from one

source to another. Over a period of time, possibilities include

settling, amalgamations or other forms of concentration.

Crude oil is common in our industry. Mercury is one of the major

toxic elements found in waste from oil and gas industries. Due to

its abundant availability, it has a wide range of environmental

and health impacts. Once disposed into atmosphere, it starts

25 | P a g e

transforming continuously into various other forms. It also moves

upward in food chain causing various health hazards. So we have

to remove mercury from crude oil and natural oil to avoid these

environmental and health impacts.

8.Recommendations Enforce Provision of Basel Convention

Formulate and Promulgate National Legislation

Develop Mercury Relevant NEQS

Establish National Mercury and Heavy Metals R&d Centers

Minimize Generation of Mercury Wastes

Apply Management Practices for Curbing Mercury Release Into

Environment.

9.GlossaryActivated Carbon is a form of carbon that has been processed

to make it extremely porous and thus to havea very large surface area available foradsorption and chemical reactions.

Amalgamation is the process of combining or unitingmultiple entities into one form. Amalgamationcombines mercury and another element tocreate amalgam (chemistry), used indentistry, chemistry, and mining.

Basel convention The Basel Convention on the Control ofTransboundary Movements of Hazardous Wastesand Their Disposal, usually known as theBasel Convention, is an international treaty

26 | P a g e

that was designed to reduce the movements ofhazardous waste between nations, andspecifically to prevent transfer of hazardouswaste from developed to less developedcountries (LDCs).

Disinfection the act of disinfecting, using specializedcleansing techniques that destroy or preventgrowth of organisms capable of infection.

Genotoxic a toxic agent that damages DNA molecules in genes, causing mutations, tumors, etc.

Hydrotreating Oil refinery catalytic process in whichhydrogen is contacted with petroleumintermediate or product streams to removeimpurities, such as oxygen, sulfur, nitrogen,or unsaturated hydrocarbons. 

Organometallic pertaining to or noting an organic compound containing a metal or a metalloid linked to carbon.

Pacific Rim area are the lands around the rim of the Pacific Ocean.

Pigging operation in the context of pipelines refers to the practice of using devices known as "pigs" to perform various maintenance operations on a pipeline. This is done without stopping the flow of the product in the pipeline.

Pre Treatment to treat in advance or as part of a

preliminary treatment.

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Promulgate to make known by open declaration; publish;proclaim formally or put into operation (alaw, decree of a court, etc.).

Roast Treatment / Retort Treatment

Are thermal techniques and the most commonly

used for treating mercury-contaminated waste.

These Operations separate the mercury from

the rest of the waste stream and condense it

for recovery or removal.

Zeolitic any of a group of hydrated silicates ofaluminum with alkali metals, commonlyoccurring as secondary minerals in cavitiesin basic volcanic rocks: used for theirmolecular sieve properties because theyundergo dehydration with little or no changein crystal structure.

Abbreviation

FDA Food and Drug Administration

LNG Liquefied Natural Gas

MRU Mercury Removal Unit

NEQs National Environmental Quality Standards

RCRA  Resource Conservation and Recovery Act

R & D centres Research and Development centres

TCLP Toxicity characteristic leaching procedure

UOP Universal Oil Products

28 | P a g e

US EPA United States Environmental Protection Agency 

10. References1. Innovative Approach to the Mercury Control during Natural Gas

Processing by Z. Spiric, INA Naftaplin.

2. Edmonds B, Moorwood R A S, Szcepanski R, Mercury partitioning

in natural gas, GPA European Chapter Meeting, London, March

1996.

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