introduction to inviromental control in refining industry.ppt

INTRODUCTION TO ENVIROMENTAL CONTROL IN REFINING INDUSTRY

ByDr.Amer Abdel Razik Amer

2.1 Driving forces, hurdles and potential.

2.3 Environmental discharges.

2.4 Best available environmental technologies for specific processes

2. Petroleum Industry

2.2 The Petroleum Refining Industry2.2.1 Definition2.2.2 Primary Products2.2.3 Industrial Processes in the Petroleum Refining Industry2.2.4 Refinery flow diagram

2.3.1 Refinery air emission sources2.3.2 Types of wastewater produced in refineries2.3.3 Refinery Residuals2.3.4 Environmental discharges by process

HURDLES

The petroleum industry has been dramatically impacted over the last three decades by geopolitical disruptions and volatile world oil prices. Today refiners must deal with:

Increasing capital and operating costs of environmental compliance.

Volatile crude prices

Crude quality variability

Low marketing and transport profit margins

The environmental impact produced by the petroleum industry covers the effects of all and each step in the energetic cycle, which means:

•explotation•extraction •refining •transportation •storage •consumption •releases

HURDLES

1. PETROLEUM REFINING INDUSTRY

Petroleum refining is the physical, thermal and chemical separation of crude oil into its major distillation fractions which are then further processed through a series of separation and conversion steps into finished petroleum products.

Petroleum refineries are a complex system of multiple operations and the operations used at a given refinery depend upon the properties of the crude oil to be refined and the desired products.

DEFINITION

INDUSTRIAL PROCESSES IN THE PETROLEUM REFINING INDUSTRY

The process of oil refining involves five major processes which are briefly described:

SEPARATION PROCESSES

These processes involve separating the different fractions of hydrocarbon compounds that make up crude oil base on their boiling point differences. Additional processing of these fractions is usually needed to produce final products to be sold within the market.

• Atmospheric distillation• Vacuum distillation• Light ends recovery (gas processing)

SEPARATION CONVERSION TREATING BLENDING AUXILIARY

ASSOCIATED OPERATIONS

In order to understand where the environmental discharges come from, we will make a review of the refining process.


ASSOCIATED OPERATIONS

Include processes used to bread down large longer chain molecules into smaller ones by heating using catalysts.

• Cracking (thermal and catalytic)• Reforming• Alkylation• Polymerization• Isomerization• Coking• Visbreaking

CONVERSION PROCESSES



ASSOCIATED OPERATIONSTREATING PROCESSES

Petroleum-treating processes are used to separate the undesirable components and impurities such as sulfur, nitrogen and heavy metals from the products.

• Hydrodesulfurization• Hydrotreating• Chemical sweetening• Acid gas removal• Deasphalting



ASSOCIATED OPERATIONSBLENDING/COMBINATION PROCESSES

These are used to create mixtures with the various problem fractions to produce a desired final product, some examples of this are lubricating oils, asphalt, or gasoline with different octane ratings.

• Storage• Blending• Loading• Unloading



ASSOCIATED OPERATIONSAUXILIARY PROCESSES

Processes that are vital to operations by providing power, waste treatment and other utility services. Products from these facilities are usually recycled and used in other processes within the refinery and are also important in regards to minimizing water and air pollution.

• Boilers• Waste water treatment• Hydrogen production• Sulfur recovery plant


Stabilizer

At m

osp

her i

cD

isti

llat i

on

VacuumDistillation

SweeteningUnit

Visbreaker

Hydrotreating

CatalyticCracking

Solvent Extraction and

Dewaxing

LPH and Gas

Gasoline

Naphta

Middle Distillates

Gas Oil

Lube-BaseStocks

Sweet Gasoline

Middle Distillates

Gas

Gasoline

Light Gas Oil

Lube Oil

Waxes

Gasoline, Naphtha and Middle distillates

Fuel Oil

Asphalt

Tre

ati

ng a

nd B

lend

ing

Refinery fuel gas

Refinery fuel oil

Industrial fuels

Asphalts

Greases

Lube oils

Aviation fuels

Diesels

Heating oils

LPG

Gasoline

Solvents

Washed Crude

2.REFINERY FLOW DIAGRAM

3. ENVIRONMENTAL DISCHARGES

Now, that we have seen an overview of the Refinery Process, we can make some questions:

What is this industry discharging?How is it discharged? Where does it come from?

In order to answer these questions, this section will show:

Air emission sourcesWastewater sourcesResidualsEnvironmental discharges by process

3.1 REFINERY AIR EMISSIONS SOURCES

COMBUSTION EMISSIONS: associated with the burning of fuels in the refinery, including fuels used in the generation of electricity.

EQUIPMENT LEAK EMISSIONS (fugitive emissions): released through leaking valves, pumps, or other process devices. They are primarily composed of volatile compounds such as ammonia, benzene, toluene, propylene, xylene, and others.

PROCESS VENT EMISSIONS: typically include emissions generated during the refining process itself. Gas streams from all refinery processes contain varying amounts of refinery fuel gas , hydrogen sulfide and ammonia.

STORAGE TAND EMISSIONS released when product is transferred to and from storage tanks.

WASTEWATER SYSTEM EMISSIONS from tanks, ponds and sewer system drains.

3.2 TYPES OF WASTEWATER PRODUCED IN REFINERIES

SURFACE WATER RUNOFF is generated intermittently and may contain constituents from spills to the surface, leaks in equipment and materials in drains.

COOLING WATER which normally does not come into contact with oil streams and contains less contaminants than process wastewater. It may contain chemical additives used to prevent scaling and biological growth in heat exchanger pipes.

PROCESS WASTEWATER that has been contaminated by direct contact with oil accounts for a significant portion of total refinery wastewater. Many of these are sour water streams and are also subjected to treatment to remove hydrogen sulfide and ammonia.

3.3 REFINERY RESIDUALS

Most refinery residuals are in the form of sludge, spend caustics, spend process catalysts, filter clay, and incinerator ash.

NON-HAZARDOUS RESIDUALS are incinerated, landfilled or regenerated to provide products that can be sold off-site or returned for re-use at a refinery.

HAZARDOUS WASTES are regulated under the Resource Conservation and Recovery Act (RCRA). Listed hazardous wastes include oily sludge, slop oil emulsion solids, dissolved air flotation floats, leads tank bottom corrosion solids and waster from the cleaning of heat exchanger bundles.TOXIC CHEMICALS are also use in large quantities by refineries. These are monitored through the Toxic Release Inventory (TRI).

These residuals could be classified as follows:

PollutantAverage ratekg/t of crude

Particulate matter 0.8Sulfur oxides 1.3Nitrogen oxides 0.3Benzene, tolueneand xylene (BTX) 0.0025VOC 1

PollutantAverage ratemg/l ofwastewater

BOD 150-250COD 300-600Phenols 20-200Oil 100-300Benzene 1-100Benzopyrene 1-100Heavy metals 0.1-100Chrome 0.2-10

3.4 DISCHARGES

AIR EMISSIONSLIQUID EFFLUENTS

Approximately 3.5-5 cubic meters of wastewater per ton of crude are generated when cooling water is recycled.

Refineries generate solid wastes and sludges ranging from 3 to 5 kg per ton of crude processed, 80% of this sludges may be considered hazardous because or the presence of toxic organics and heavy metals.

SOLID WASTES

Process Air Emissions Process Waste Water Residual Wastes Generated

Crude oil desalting Heater stack gas (CO,

SOx, NOx, hydrocarbons

and particulates), fugitive emissions (hydrocarbons)

Flow = 2.1 Gal/Bbl Oil,

H2S, NH3, phenol, high

levels of suspended solids, dissolved solids, high BOD, high temperature

Crude oil/desalted sludge (iron rust, clay, sand, water, emulsified oil and wax, metals)

Atmospheric distillation

Heater stack gas (CO,


and particulates), fugitive emissions (hydrocarbons)

Vacuum distillation Steam ejector emissions (hydrocarbons), heater

stack gas (CO, SOx,

NOx, hydrocarbons and

particulates), vents and fugitive emissions (hydrocarbons).

Thermal Cracking/Visbreaking



and particulates), vents and fugitive emissions (hydrocarbons)

Flow = 2.0 Gal/Bbl Oil,

H2S, NH3, phenol,

suspended solids, high pH, BOD, COD.

Typically, little or no residual waste generated.

Coking Heater stack gas (CO,


and particulates), vents and fugitive emissions (hydrocarbons) and decoking emissions (hydrocarbons and particulates).

Flow = 1.0 Gal/Bbl High

pH, H2S, NH3,

suspended solids, COD.

Coke dust (carbon particles and hydrocarbons).

Flow = 26 Gal/Bbl Oil,

H2S, NH3 suspended

solids, chlorides, mercaptans, phenol, elevated pH.

Typically, little or no residual waste generated.

3.4 ENVIRONMENTAL DISCHARGES BY PROCESSPART 1


Catalytic Cracking Heater stack gas (CO,


and particulates), fugitive emissions (hydrocarbons) and catalyst regeneration

(CO, NOx, SOx, and

particulates).

Flow 1.5 Gal/Bbl High levels of oil, suspended solids, phenols

cyanides, H2S, NH3,

high pH, BOD, COD.

Spent catalysts (metals from crude oil and hydrocarbons), spent catalyst fines from electrostatic precipitators (aluminum silicate and metals).

Catalytic Hydrocracking



and particulates), fugitive emissions (hydrocarbons) and catalyst regeneration

(CO, NOx, SOx, and

catalyst dust).

Flow = 2.0 Gal/Bbl High COD, suspended solids,

H2S, relatively low levels

of BOD.

Spent catalysts fines (metals from crude oil, and hydrocarbons).

Hydrotreating/Hydroprocessing



and particulates), vents and fugitive emissions (hydrocarbons) and catalyst regeneration

(CO, NOx, SOx, and

catalyst dust).

Flow = 1.0 Gal/Bbl H2S.

NH3, High pH, phenols

suspended solids, BOD, COD.

Spent catalyst fines (aluminum silicate and metals).

Alkylation Heater stack gas (CO,



Low pH, suspended solids, dissolved solids,

COD, H2S, spent

sulfuric acid.

Neutralized alkylation sludge (sulfuric acid or calcium fluoride, hydrocarbons).

Isomerization Heater stack gas (CO,



Low pH, chloride salts, caustic wash, relatively

low H2S and NH3.

Calcium chloride sludge from neutralized HCl gas.



Polymerization H2S from caustic

washing.

H2S, NH3, caustic wash,

mercaptans and ammonia, high pH.

Spent catalyst containing phosphoric acid.

Catalytic Reforming Heater stack gas (CO,


and particulates), HCl potentially in light ends), vents and fugitive emissions (hydrocarbons)

Flow = 6.0 Gal/Bbl High levels oil, suspended solids, COD. Relatively

low H2S.

Spent catalyst fines from electrostatic precipitators (alumina silicate and metals).

Solvent Extraction Fugitive solvents Oil solvents Little or no residual wastes generated.

Dewaxing Fugitive solvents, heaters Oil solvents Little or no residual wastes generated.

Propane Deasphalting



and particulates), fugitive propane.

Oil solvents Little or no residual wastes generated.

Merox treating Vents and fugitive emissions (hydrocarbons and disulfides).

Little or no wastewater generated

Spent Merox caustic solution, waste oil-disulfide mixture.

Wastewater treatment

Fugitive emissions (H2S,

NH3, and hydrocarbons)

Not Applicable API separator sludge (phenols, metals and oil), chemical precipitation sludge (chemical coagulants, oil), DAF floats, biological sludges (metals, oil, suspended solids), spent lime.



Gas Treatment and Sulfur Recovery

SOx, NOx, and H2S from

vent and tail gas emissions.

H2S, NH3, amines,

Stretford solution.

Spent catalyst.

Blending Fugitive emissions (hydrocarbons)


Little of no residual waste generated.

Heat Exchanger cleaning

Periodic fugitive emissions (hydrocarbons)

Oily wastewater generated

Heat exchanger sludge (oil, metals, and suspended solids)

Storage Tanks Fugitive emissions (hydrocarbons)

Water drained from tanks contaminated with tank product

Tank bottom sludge (iron rust, clay, sand, water, emulsified oil and wax, metals)

Blowdown and flare Combustion products

(CO, SOx, NOx, and

hydrocarbons) from flares, fugitive emissions


Little or no residual waste generated.


4 REGULATORY ISSUES

The Petroleum Refining Industry is unique in that the environmental requirements aimed at the industry are of two basic types:

For the purpose of this module, we focus on refineries, which will be used to show some Process Integration techniques.

Petroleum refineries are complex plants, and the combination and sequence of processes is usually very specific to the characteristics of the raw material and the products. For this reason the regulations for this sector become very specific and dispersed because an unit have regulations for water, air and land discharges, all of these managed by different official documents.

Requirements directed at reducing the environmental impacts of the refineries themselves.

Requirements mandating specific product qualities for the purpose of reducing the environmental impacts associated with the downstream use of the product.

In the case of the United States, there are numerous federal regulations affecting the Refinery Industry. The Environmental Protection Agency (EPA) contains several regulatory documents depending on the kind of resource that they pretend to protect, (e.g. Air, water and soil).

Each one of these documents presents requirements which apply for every industrial sector. Then, when the requirements for a certain industry are needed, specific parts of the document should be used. For example,

The Clean Air Act Amendments of 1990 has some programs for reducing air emissions from industry in which refineries are included:

New Source Review, New Source Performance StandardsNational Emission Standards for Hazardous Air Pollutants

At the same time, the New Source Performance Standards have some sections for Refineries:

Subpart J Standards of Performance for Petroleum RefineriesSubpart KKK Standards of Performance for Volatile Organic Liquid Storage Vessels.Subpart GG Standard of Performances for Stationary Gas Turbines.Subpart GGG Standards of Performance for Equipment Leaks of VOC in Petroleum Refineries

4.1 U.S. REGULATIONS

Requirement Provisions That Affect Petroleum Refining

Clean air Act of 1970 (CAA) and regulations National Ambient Air Quality Standards (NAAQS) fix six constituents; new standards underNAAQS that require control of particulate matter of 2.5 microns or smaller; lead-free gasoline;low sulfur fuel; reformulated gasoline; hazardous air pollutants; visi

Clean Air Act Amendments of 1990 (CAAA) and regulations thereunder.

Oxygenated Fuels Program for “ nonattainment areas” low sulfur highway diesel fuel;Reformulated fuels Program; Leaded Gasoline Removal Program; Reid Vapor pressureregulations to reduce VOCs and other ozon precursors; New Source Review for new orexpande

Resource Conservation and Recovery Act (RCRA)

Standards and regulations for handling and disposing of solid and hazardous wastes.

Clean Water Act (CWA) Regulates discharges and spills to surface waters; wetlands.

Safe Drinking Water Act (SDWA) Regulates disposal of wastewater in underground injection wells

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)

“superfund”, liability for CERCLA hazardous substances could apply to wastes generatedduring refining, includes past releases, exempts petroleum and crude oil; provides for naturalresource damages.

Emergency Planning and Community Right-to-Know (EPCRA).

Requires annual reporting on the releases and transfers of listed toxic chemicals; reportingpresence of “extremely hazardous substances’ in excess or threshold planning quantities;reporting certain releases of CERCL hazardous substances and EPCRA extrem

1990 Oil Pollution act and Spill Prevention Control and Countermeasure Plans

Liability against facilities that discharge oil to navigable waters of pose a threat of doing so.

OSHA Health Standards and Process Safety Management Rules

Limits benzene and other chemical exposures in the workplace, safety plans required in allrefineries.

Toxic Substances Control Act Collection of data on chemicals for risk evaluation, mitigation and control; can ban chemicalsthat pose unreasonable risks.

Energy Policy Act of 1992 Use of alternative fuels for transportation; efficiency standards for new federal buildings,buildings with federally backed mortgages, and commercial and industrial equipment; R&Dprograms for technologies; will reduce demand for petroleum products.

FEDERAL REQUIREMENTS AFFECTING THE REFINERY INDUSTRY

Parameter Maximum valuePM 50

Nitrogen oxidesa 460

Sulfur oxides 150 for sulfur recovey units; 500 for other

unitsNickel and vanadium (combined)

2

Hydrogen sulfide 152

Parameter Maximum valuepH 6--9BOD 30COD 150TSS 30Oil and grease 10Chromium Hexavalent 0.1 Total 0.5Lead 0.1Phenol 0.5Benzene 0.05Benzo(a)pyrene 0.05Sulfide 1

Nitrogen(total)a 10Temperature increase <=3 C

Besides all these complicated regulations, an specialized agency of the United Nations, the World Bank, has established emission levels for the design and operation of refineries, although country legislation should be accomplished. The guidelines given below present emissions levels normally acceptable to the World Bank Group.

Emissions from the Petroleum Industry(milligrams per normal cubic meter)

Effluents from the Petroleum Industry(milligrams per liter)

Generation of sludges should be minimized to 0.3 kg per ton of crude processed, with a maximum of 0.5 kg per ton of crude processed.

Solid Wastes

4.3 GENERAL REGULATIONS

World Band Group, 1998. Pollution Prevention and Abatement Handbook. World Bank Group. Pages 377-381.

http://www.worldbank.org/

Primary wastewater treatment

Consists on the separation of oil, water and solids in two stages.

1st stageAPI separator or

Corrugated plate interceptor.

2nd stageChemical and physical methods are utilized to separate emulsified oils from the wastewater.

www.panamenv.com

Physical methods may include the use of series of settling ponds with a long retention time, or the use of dissolved air flotation (DAF).

Chemicals, such as ferric hydroxide or aluminum hydroxide are used to coagulate impurities.

More information about the equipment

More information about the equipment

www.panamenv.com

5 ENVIRONMENTAL TECHNOLOGIES USED IN THE PETROLEUM INDUSTRY

Secondary wastewater treatment

Dissolved oil and other organic pollutants may be consumed biologically.

Biological treatment may require oxygen through different techniques:

• Activated sludge units• Trickling filters• Rotating biological contactors.

Generates bio-mass waste which is treated an aerobically.

Polishing

Some refineries employ it as an additional stage of wastewater treatment to meet discharge limits.

• Activated carbon• Anthracite coal• Sand

5.1 ENVIRONMENTAL TECHNOLOGIES PETROLEUM INDUSTRY

In order to meet the SOx emissions limits and to recover saleable sulfur, refinery process off-gas streams should be treated.

Process off-gas streams contain high concentrations of:

hydrogen sulfide + light refinery fuel

gases.

This is accomplished by: • Dissolving the hydrogen sulfide in a chemical solvent such as diethanolamine (DEA) in an absorption tower.• Using dry adsorbents such as molecular sieves, activated carbon, iron sponge and zinc oxide.

These fuel gases (methane and ethane) need to be separated before elemental sulfur can be

recovered.

Amine + hydrogen sulfide Is then heated and steam stripped to remove the hydrogen sulfide gas.

Two processes are typically combined to remove sulfur from the hydrogen sulfide gas streams:

Claus Process

Beaven Process

Scot Process

Wellman-Land Process

hydrogen sulfide


Gas treatment and Sulfur Recovery

Other emissions sources come from periodic regeneration of catalysts, these emissions may

contain:

high levels of carbon monoxide + particulates + VOCs.

CARBON MONOXIDE BOILERTo burn carbon monoxide and VOCs

ELECTROSTATIC PRECIPITATOR OR CYCLONE SEPARATORTo remove particulate matter

Before being released to the atmosphere


Gas treatment

Solid waste treatment

Sludge treatment use bioremediation or solvent extraction, followed by combustion of the residues or by use for asphalt. The residue could require stabilization before disposal to reduce the leachability of toxic metals.

www.e2t.com/E2T/app_pc05.htm

More information:www.ppcesp.com

Petroleum

As we showed in the statistics section, petroleum industries which are very important for the economy and development and also are causing serious environmental problems.

STUDY CASE

PETROLEUM REFINERY WASTES

A major concern in refineries is the release of phenols, although described as this, the category may include a variety of similar chemical compounds among which are polyphenols, chlorophenols, and phenoxyacids. The concern is because of their toxicity to aquatic life and the high oxygen demand they sponsor in the streams that receive it. Phenols are toxic to fish and also they can cause taste and odor problems when present in potable water.

Stabilizer

At m

osp

her i

cD

isti

llat i

on

VacuumDistillation

SweeteningUnit

Visbreaker

Hydrotreating

CatalyticCracking

Solvent Extraction and

Dewaxing

LPH and Gas

Gasoline

Naphta

Middle Distillates

Gas Oil

Lube-BaseStocks

The first step in a petroleum refinery is to preheat the crude, then it is washed with water to remove various salts.

Tre

ati

ng a

nd B

lend

ing

Refinery fuel gas

Refinery fuel oil

Industrial fuels

Asphalts

Greases

Lube oils

Aviation fuels

Diesels

Heating oils

LPG

Gasoline

Solvents

PROCESS DESCRIPTIONSweet Gasoline

Middle Distillates

Gas

Gasoline

Light Gas Oil

Wastewater, R1

Lube Oil

Waxes

Gasoline, Naphtha and Middle distillates

Fuel Oil

Asphalt

Wastewater, R2

Gas oil and heavy stocks are fed to a catalytic-cracking unit to be converted to lower molecular weight fractions. The main waste stream from this process is the condensate from stripping in the fractionating column. This condensate commonly contains ammonia, phenols and sulfides as contaminants, this has to be stripped to remove ammonia and sulfides. The bottom product of the stripper must be treated to eliminate phenols.

The light gas oil leaving the fractionator can serve as a lean-oil solvent in a phenol extraction process, being this a beneficiary mass transfer because in addition to purify water, phenols can act as oxidation inhibitors and as color stabilizers.

The main objectives of visbreaking are to reduce the viscosity and the pour points of vacuum-tower bottoms and to increase the feed stocks to catalytic cracking. The source of wastewater is the overhead accumulator on the fractionator, where water is separated from the hydrocarbon vapor. This water contains phenols, ammonia an sulfides

“Hydroskimming” Refinery (1st Generation)

CatalyticReforming

Desulfurization

DHT

C

D

U

Alkylation

Merox

GasplantSulfur Plant

Kerosene

Gasoil

AtmosphericResidue

Naphtha

Gas

LPG + BUTANE+ PROPANE

MOTOR SPIRIT

JET FUEL

DIESEL

HEATINGGASOIL

BUNKER FUEL

HEAVY FUEL

LIGHT NAPHTHA TOPETROCHEMISTRY

SULFURFUEL GAS

Reformate

Alkylate

Hydrogen

C3 + C4

C1 + H2S

Sulfur rich gas

“Conversion” Refinery (2nd Generation)

CatalyticReforming

Desulfurization

CatalyticCracking

Visbreaking

DHT

VDU

C

D

U

Alkylation

Merox

MTBE

Gasplant

Bitumen Plant

Sulfur Plant

CRUDEKerosene

Gasoil

AtmosphericResidue

Wax

VacuumResidue

Naphtha

Gas


MOTOR SPIRIT

JET FUEL

DIESEL

HEATINGGASOIL

BUNKER FUEL

HEAVY FUEL


SULFURFUEL GAS

BITUMEN FOR ROAD CONSTRUCTION

Visbroken naphthaVisbroken Gasoil

Visbroken Residue

Light Cycle Oil

Heavy Cycle Oil

Reformate

Alkylate

MTBE

Hydrogen

C3 + C4

Cat Cracked Spirit

C1 + H2S

Sulfur rich gas

“Deep Conversion” Refinery (3rd Generation)

CatalyticReforming

Desulfurization

CatalyticCracking

Visbreaking

DHT

ARDS

VDU

C

D

U

Alkylation

Merox

MTBE

Gasplant

Bitumen Plant

Sulfur Plant

CRUDEKerosene

Gasoil

AtmosphericResidue

Wax

VacuumResidue

Naphtha

Gas


MOTOR SPIRIT

JET FUEL

DIESEL

HEATINGGASOIL

BUNKER FUEL

HEAVY FUEL


SULFURFUEL GAS

BITUMEN FOR ROAD CONSTRUCTION

Visbroken naphthaVisbroken Gasoil

Visbroken Residue

Light Cycle Oil

Heavy Cycle Oil

Reformate

Alkylate

MTBE

Hydrogen

Hydrogen

C3 + C4

Residue

Gasoil

Cat Cracked Spirit

C1 + H2S

Sulfur rich gas

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introduction to inviromental control in refining industry.ppt