Process Engineering Equipment Handbook Episode 3 Part 5 ppsx

TABLE P-40 VCR8 Design Features, Advantages, and BenefitsDriver Vertical motor with solid shaft Precision alignment Improved seal and bearing life stand assembly Integral thrust bear

to the application of diffusion coatings, or in advanced ion and plasma-typesurfacing techniques.

Vacuum pumps are used for drying, distillation, and evaporation Lower boilingtemperatures attained under vacuum preserve nutrients and improve taste, quality,and shelf life of products such as candies, jams, pharmaceuticals, and many mildproducts Deaeration is needed for products such as meat pastes, sauces, soups,cellulose, latex, bricks, tiles, sewer pipes, and pottery clay Also, vacuum conveyance

of dangerous, viscous, contaminated, powdery, flaky, bulky, or simply hard-to-handlematerials or products is used The author remembers the ease and utter simplicitywith which laminated plastic toothpaste tubes are transferred in partially

FIG P-320 Hydraulic range chart (Type VCR 8) (Source: Sulzer Pumps.)

evacuated, transparent plastic pipes from the forming machine at one end of theplant to the filling equipment at the other end of the building.

With a profusion of processes and applications thus benefiting from vacuumpumps, it is not surprising that many different types and styles, sizes and models,and configurations and variations of vacuum producing machinery are available tothe user The familiar steam, gas, and fluid jet injectors/eductors must beacknowledged as prime vacuum producers; however, we will only mention them inpassing because they lack moving parts and thus do not fit our definition of

“machinery.”

Vacuum pumps are often classified in two broad categories: dry type and liquidtype Dry types include lobe, rotary piston, sliding vane, and even diaphragmP-312 Pumps

FIG P-321 Hydraulic range chart (Type VCR 8) (Source: Sulzer Pumps.)

TABLE P-40 VCR8 Design Features, Advantages, and Benefits

Driver  Vertical motor with solid shaft  Precision alignment  Improved seal and bearing life stand

assembly  Integral thrust bearing  Axial and radial setting of rotor  Standard driver may be selected

 Controls hydraulic thrust  Improved seal life

 Driver alignment  Controls motor radial position  Reduced maintenance time positioning screws

 Spacer coupling  Allows seal and bearing  Reduced maintenance time

maintenance without disturbing driver

 Dimpled location  Consistent vibration monitoring  Trend for planned maintenance Head  ANSI B16.5 class 300 flanges  Consistent with process piping  Use of standard pipe flanges

 Nozzle load capability per  Simplifies piping layout  Reduces piping layout costs API 610

 Complies with API 682,  Allows use of API 682 single  Improved seal life, reduced

 Allows interchangeability  Reduced inventory

 Throttle bushing assembly  Controls seal chamber pressure  Improved seal life

 Provides rotor stiffness

 Allows use of various API 610  Greater flexibility piping plans

Column  Flanged and bolted with  Controls axial and radial  Improved reliability

 Bearing bushing spacing per  Ensures adequate separation  Improved reliability

Bowl  Flanged and bolted with  Controls axial and radial  Improved reliability

 Low NPSH first-stage impeller  Reduced pump setting length  Reduced construction cost

 Between bearings first-stage  Reduced deflection  Improved reliability

impeller design

 Impeller keyed to shaft  Positive drive and positioning  Improved reliability

 Impellers hydraulically thrust  Reduced thrust load  Improved bearing life

balanced

 Single piece shaft  Simplifies assembly  Ease of maintenance

construction £16 feet  Controls runout  Improved reliability

 Dynamically balanced  Reduced unbalance  Improved seal life

 Replaceable wear surfaces  Allows refurbishment to as-  Reduced total life cycle cost

new condition Suction  600psi pressure rating  Consistent with process  Improved plant reliability

assembly

 Controlled fluid velocities  Reduces internal losses  Improved first-stage impeller

 Reliable suction performance life

 Internal or external drain  Allows evacuation of process  Reduces maintenance costs

fluids

 Separate mounting plate  Allows through bolting on  Improved maintenance and

 Soleplate optional  Allows foundation to be  Simplified construction process

completed prior to pump installation

 Confined gasket  Controlled compression ensures  Reduced risk of leakage

reliable pressure retention

FIG P-322 Pump external view (type CD 8) (Source: Sulzer Pumps.)

Design  Full-range coverage  Selections fall within 80% to  Smooth operation

110% of best efficiency point  Longer service life

 Optimized efficiency

 Full compliance with API 610  Heavy duty design and  Longer reliable service

8th edition requirements construction  Suitable for 3 years uninterrupted

service and 20 year service life Pressure  Symmetrical, double end cover  Improved maintenance access,  All surfaces accessible

casing construction cleanout and decontamination  Completely drainable

capabilities  Reliable high-temperature operation

 Uniform warming  Clockwise or counterclockwise

 Improved flexibility of application rotation with same component parts

 Cast construction with double  Reduced radial loads  Reduced rotor deflection

entry  Symmetry of flow into impeller  Improved suction characteristics

 Centerline mounting with  Suitable for operation in wide  Reduced misalignment problems robust feet range of temperatures up to 800°F  Reduced maintenance

 Integral end cover and  Stiffer support eliminates  Reduced frame vibration

bearing hanger possible frame resonance  Improved bearing and seal life

 Reduced number of component parts  Simplified maintenance

 Available in various  Suitable for operation in wide  Optimized material selection to metallurgies, including S-4, range of services ensure appropriate service life S-6, C-6 and A-8

 Seal chamber dimensions  Suitable for state-of-the-art  Improved seal interchangeability compliant with API 682 mechanical seal technology and seal life

Impeller  Double suction impeller  Minimal axial loads  Improved bearing life

 Improved NPSH margins

 9000 to 11,000Nss suction  Stable suction performance  Reduced vibration

hydraulics available throughout entire flow range  Improved bearing and seal life

 5 vane staggered construction  Reduced hydraulic pulsations  Reduced vibration

 Simple and effective impeller  Axially and radially secured in  Secure in operation through

 Easily maintained

 Enclosed impeller  Higher efficiencies  Reduced power consumption

 No impeller setting

 Dynamic balance to 4W/N  Minimized dynamic unbalance  Reduced vibration

Shaft  Heavy duty shaft with  Higher torque transmission  Higher torsional stress safety

 Lower static and dynamic deflection  Improved reliability

 Stiff shaft design  Ensures separation from critical  Smoother operation at all

speeds throughout entire allowable operating speeds operating range

 Taper shaft extension  Simplified coupling, bearing and  Reduced maintenance downtime

seal maintenance Bearing  All steel load bearing  Reliable long-term service  Maximized bearing reliability and

 40° angular contact thrust  Selected for minimum 25,000 hours

 Deep groove radial bearing  Heavy duty carrying capability

 INPRO TM labyrinth seals  Minimized ingress of oil  Improved bearing life

fitted as standard contaminants

 Fan cooling or water cooling  Efficient cooling features ensure

options available cool running of bearings under

all pump operating temperatures

P-323 Design features (type CD 8) (Source: Sulzer Pumps.)

FIG P-324 Thrust bearing assembly (type CD 8 option) High capacity fan; water cooling; inboard heat dissipator; purge or pure mist oil lubrication (Source: Sulzer Pumps.)

FIG P-325 Radial bearing assembly (type CD 8 option) Water cooling; inboard heat dissipator; purge or pure mist oil lubrication (Source: Sulzer Pumps.)

FIG P-326 Impeller (type CD 8 option) Integral wear surfaces; nonmetallic wear rings (Source: Sulzer Pumps.)

P-318 Pumps

FIG P-327 Hydraulic range chart (type CD 8) (Source: Sulzer Pumps.)

pumps Liquid vacuum pumps include liquid jet and liquid ring pumps Figure

P-335 shows the operating ranges for many of these pumps It should be noted thatthere is considerable overlap among ranges

The most important vacuum producers and their respective operating modes andfeatures are of interest to use in the order listed in Fig P-335

Single-stage liquid ring pumps

Figure P-336 depicts the operating principle of a liquid ring pump Its circular pumpbody (A) contains a rotor that consists of a shaft and impeller (B) Shaft and impellercenterlines are positioned parallel, but eccentrically offset relative to the centerline

of the pump body The amount of eccentricity is related to the depth of the liquidring (C) The liquid ring is formed by introducing service liquid, normally water,via the pump suction casing (L) and through the channel (D) positioned in thesuction port plate (E) The centrifugal action of the rotating impeller forces theliquid toward the periphery of the pump body By controlling the amount of serviceliquid within the pump body where the impeller blades are completely immersed

to their root at one extreme (F) and all but their tips exposed at the other extreme(G), optimum pumping performance will be attained

FIG P-328 Hydraulic range chart (type CD 8) (Source: Sulzer Pumps.)

FIG P-329 The use of rapid prototyping and computational fluid dynamics allows the optimization

of pump performance (Source: Sulzer Pumps.)

P-320 Pumps

FIG P-330 Model testing, the next step, is necessary in the development process to validate numerical calculation done during computational fluid dynamics (CFD) calculations (Source: Sulzer Pumps.)

FIG P-331 Once successful model testing has been achieved, 3D computer-aided design (CAD) and computer-aided manufacturing (CAM) are implemented (Source: Sulzer Pumps.)

When this pumping action is achieved, the vapor to be handled is induced through the suction port (H) when the depth of impeller blade immersion is beingdecreased Then as the immersion increases, the vapor is compressed anddischarged through the discharge port (J) in the intermediate port plate (K) Asthere is no metal-to-metal contact between the impeller and the pump body and

FIG P-332 The final step is the creation of patterns Modern techniques including stereolithography are adopted to ensure foundry patterns accurately reflect design and manufacturing requirements during the casting process (Source: Sulzer Pumps.)

intermediate plates, the need for lubrication is eliminated and wear is reduced to

a minimum

During the compression cycle, heat is being imparted to the liquid ring In order

to maintain a temperature below the vapor point, cooling must be applied Thiscooling is achieved by continuously adding a cool supply of service liquid to theliquid ring The amount of coolant added is equal to that discharged through thedischarge port (J) together with the compressed vapor The mixture of vapor andliquid is then passed to subsequent stages and eventually through the pumpdischarge for separation

An entire vacuum pumping system is shown in Fig P-337 This so-called fullsealant recovery system is used to conserve sealant and/or where suitable orcompatible sealant is not available from an outside source Periodic sealant makeupand/or purge may be required Full recirculation of sealant is provided from thedischarge separator tank Cooling is provided by running recirculated sealantthrough a heat exchanger Separate cooling liquid or gas is required

Liquid jet vacuum pumps

A typical liquid jet pump is illustrated in Fig P-338 A centrifugal pump circulateswater (the usual hurling liquid) through the multijet nozzle and venturi and returns

it to the separation chamber The water, forced at high velocity across the gapbetween the nozzle and venturi, entrains the air and gases in multiple jet streams,creating a smooth, steady vacuum in the air suction line and vacuum system This

P-322 Pumps

FIG P-333 Pump section (type CP) (Source: Sulzer Pumps.)

FIG P-334 Pump performance range (type CP) (Source: Sulzer Pumps.)

FIG P-335 Typical pressure ranges for various vacuum pumping devices (Source: Stokes Division of Pennwalt

Corporation, Philadelphia, Pa.)

FIG P-336 Operating principle of liquid vacuum pumps (Source: SIHI Pumps, Inc., Grand Island, N.Y.)

P-324 Pumps

FIG.P-338 (A) Typical liquid jet vacuum pump (B) Cutaway view of liquid vacuum pump (Source: Kinney Vacuum

Company, Boston, Mass.)

FIG P-337 Liquid ring vacuum pumping system with full sealant recovery (Source: Kinney Vacuum Company, Boston, Mass.)

mixture is discharged through the venturi tangentially into the separation chamber,causing the water in the separation chamber to rotate, which results in a centrifugalaction that forces the water to the periphery of the chamber, while the air isseparated and discharged When the hurling liquid is water, it is cooled by acontinuous flow of cooling water into the separation chamber Where processrequirements allow and economy is an important factor, automatic controls andother cooling methods are often utilized.

R Reactors; Chemical Reactors

There are two main distinctions between reactors, batch and continuous In a batchreactor a certain amount of the reactants is handled at one time In continuousreactors, the process continues indefinitely This is the most common type of reactor

in petrochemical and refinery service

A batch reactor is a closed system An example is a batch of paper pulp being

made for a specific or customized application

A semibatch reactor is not a closed system This type is useful in cases such as

the manufacture of certain chemicals where a volatile chemical must be addedslowly to a nonvolatile chemical (examples include the manufacture of certainglycols)

Tubular reactors (either long bent tube or shell and tube) may be either batch or

continuous reactors

Continuous reactors are “at work” all the time This means newly introduced

reactants mix to some extent with products This extent is termed backmixing A

tower has many plates or baffles in it and experiences less backmixing as, forinstance, a tank with no plates Continuous reactors can then be found withintowers and columns Towers may be packed or plate (bubble cap or sieve tray) type.Optimum reactor design attempts to curtail the amount of “dead space” or areaswhere no reaction is taking place It is also possible to have reactants take a shorter

path than is necessary for optimum reaction This is called shortcircuiting.

Catalytic reactors are continuous reactors more often than not The main

subdivision types include: fluidized or fixed bed Fixed bed types may be eithertubular, bed, or multitray types Fluidized bed types further break down intostationary or moving (recirculating) bed types and tubular (transfer tube) types.The catalyst is generally in powdered suspension and may be removed either inbatches or continuously withdrawn and regenerated In transfer tube types, thecatalyst stays in suspension with the fluid flow through the tubes

Reactor performance is measured by its divergence from ideal conditions Plugflow means all the fluid in the reactor has the same residence time in the reactor(no mixing with fluid streams that entered the reactor at different times) Very longtube reactors with turbulent flow can approximate this condition Perfect mixingcondition means the entering fluid in the reactor is homogeneous with the materialalready in the vessel on a molecular scale (perfect mixing case) In segregatedmixing, the mixing is not uniform and pockets of fluid behave as “minireactors.”

Refineries, Petroleum*

Crude oil is the principal raw material for a petroleum refinery It may be of naturalorigin (from underground geological formations) or synthetic (recovered from tarsands) Crude oil is a mixture of many hydrocarbons and, depending on its source,varies considerably in composition and physical properties Its elementary

R-1

* Source: Environment Canada, extracts from EPS/1/PN/4, October 1995.

composition (by mass) usually falls within the following ranges: 84 to 87 percentcarbon, 11 to 14 percent hydrogen, 0 to 3 percent sulfur, 0 to 2 percent oxygen, 0 to0.1 percent nitrogen, 0 to 1 percent water, and 0 to 0.1 percent mineral salts Crudeoil may also contain trace amounts of heavy metals such as iron, arsenic, chromium,vanadium, and nickel.

Crude oils are broadly classified by hydrocarbon composition as paraffinic,naphthenic, asphaltic, mixed (contains paraffinic and asphaltic material), andaromatic base (prevalent in the Middle East)

The major steps in converting crude oil to various products are separation,

conversion, treatment, and blending In the first step, crude oil is separated into

selected fractions mainly by distillation and to a lesser extent by solvent extractionand crystallization Conversion processes are then used to change the size and shape

of the hydrocarbon molecules to increase their monetary value These processesinclude breaking molecules into smaller ones (catalytic cracking), rearrangingmolecules (catalytic reforming and isomerization), and joining molecules together(alkylation and polymerization) Impurities such as sulfur, nitrogen, and oxygencompounds that end up in intermediate products are removed or modified bytreatment processes such as desulfurization, denitrification, or treatment withchemicals (caustic soda or acid) In the final step, the refined products are usuallyblended and some additives are added to improve the quality to meet finishedproduct specifications

These processes are discussed in more detail in the following subsections Asimplified flow diagram of the various refinery processes and products is provided

in a range of specific boiling temperatures The various fractions are continuouslydrawn off and diverted for further processing or used as finished products Thelighter products are withdrawn from the top of the column whereas lower points

on the tower draw off progressively heavier fractions The tower bottoms, whichcontain the heaviest petroleum fraction, are transferred to a vacuum distillationtower for further separation

Vacuum distillation. In this process, the residue from the atmospheric distillationtower is separated under vacuum into one or more heavy gas oil streams and heavyresidual pitch

Conversion

Cracking processes. Typical cracking processes include catalytic cracking, hydrocracking, and visbreaking or coking, both of which are thermal crackingprocesses

1 Catalytic cracking is a key process used to increase the quality and quantity of

gasoline fractions The most commonly used process is the fluid bed type, whichuses a finely powdered zeolite catalyst that is kept in suspension in the reactor

by the incoming oil feed from the bottom of the reactor Upon contact with thehot catalyst, the oil vaporizes and is cracked into smaller molecules Vapors fromthe reactor are separated from the entrained catalyst and fed into a fractionator,where the desired products are removed and heavier fractions are returned tothe reactor The catalyst is deactivated by thermal degradation and throughcontact with heavy metals in the feed, necessitating regeneration or replacement.

2 Hydrocracking is basically a catalytic cracking and a hydrogeneration process.

In this process, polycyclic compounds are broken to produce single ring andparaffin-type hydrocarbons In addition, sulfur and nitrogen are removed toproduce hydrogen sulfide and ammonia These reactions occur at high temperaturesand pressures, in the presence of hydrogen and a catalyst

3 Visbreaking is an old process that was replaced by catalytic cracking and

hydrocracking It involves a mild thermal cracking operation designed to reducethe viscosity of the charge stock The feed is heated and thermally cracked inthe furnace Cracked products are routed to a fractionator where the low boilingmaterials are separated into light distillate products, while the heavy portionmay be used for coker feed or as plant fuel

Refineries, Petroleum R-3

FIG R-1 Simplified petroleum refinery process flow diagram (Source: Environment Canada.)

4 Coking processes (fluid or delayed) are used by only a few refineries in Canada.

Coking is a severe thermal cracking process in which the feed is held at highcracking temperature and low pressure so that coke will form and settle out Thecracked products are sent to a fractionator where gas, gasoline, and gas oil areseparated and drawn off, and the heavier material is returned to the coker

Rearranging processes. Catalytic reforming, which is the most widely used rearranging process, improves the octane quality of gasoline obtained from crudeoil This is achieved by molecular rearrangement of naphthenes throughdehydrogenation and of paraffins through isomerization and dehydrocyclization.The reformer catalyst, commonly platinum chloride on an alumina base, may alsocontain an activity-increasing noble metal such as rhenium In many units, thecatalyst is regenerated or replaced every 6 to 12 months In other units, the catalyst

is withdrawn continuously and regenerated on-site for further use Refineries aremore often choosing continuous reformers that do not require periodic shutdownfor catalyst regeneration as conventional reformers do The dehydrogenation anddehydrocyclization reactions produce large amounts of hydrogen as a by-productthat can be used for various hydrogen-treating processes

Combining processes. Two processes, alkylation and polymerization, are used toproduce gasoline-blending stocks from the gaseous hydrocarbons formed duringcracking processes

1 Alkylation is the reaction of an olefin with an isoparaffin (usually isobutane) in

the presence of a catalyst (either 98 percent sulfuric acid or 75 to 90 percenthydrofluoric acid) under controlled temperatures and pressures to produce high octane compounds known as alkylate These products are separated in asettler where the acid is returned to the reactor and the alkylate is furtherprocessed This hydrocarbon stream is scrubbed with caustic soda to remove acid and organically combined sulfur before passing to the fractionation section.Isobutane is recirculated to the reactor feed, the alkylate is drawn off from thebottom of the debutanizer, and the normal butane and propane are removed fromthe process

2 Polymerization is a reaction that joins two or more olefin molecules The use of

this process has been declining as both the yield and quality of the gasolineproduct are inferior to those derived from the alkylation process The feed mustfirst be treated with caustic soda to remove sulfur compounds and then withwater to remove nitrogen compounds and excess caustic soda These treatmentsare required to protect the catalyst in the reactor After treatment, thehydrocarbon feed is contacted with an acid catalyst in the reactor under hightemperature and pressure The catalyst is usually phosphoric acid or, in someolder units, sulfuric acid The polymerized product from the reactor is thentreated to remove traces of acid

Treating

Hydrotreating. Hydrotreating is a relatively mild hydrogenation process thatsaturates olefins and/or reduces sulfur, nitrogen, and oxygen compounds, along withhalides and trace metals present in the feed, without changing the boiling range ofthe feed This process stabilizes the product by converting olefins and gum-formingunstable diolefins to paraffins and also improves the odor and color of the products.Although there are various types of hydrotreating units, each has essentially thesame process flow The feed is combined with recycled hydrogen, heated to the

reaction temperature, and charged to the reactor In the presence of a catalyst(metal-sulfide), the hydrogen reacts with the hydrocarbons to form hydrogen sulfide,ammonia, saturated hydrocarbons, and free metals The metals remain on the catalyst and other products leave the reactor with the oil-hydrogen stream Thereactor products are cooled and hydrogen sulfide is removed, while hydrogen isreturned to the system The hydrocarbons are sent to a fractionator where thevarious products are separated This process is ideally suited for the production oflow sulfur diesel and furnace fuel oil.

Chemical treating. A number of chemical methods are used throughout the refinery

to treat hydrocarbon streams These can be classified into three groups: acidtreatment, sweetening processes, and solvent extraction

1 Acid treatment consists of contacting the hydrocarbons with concentrated

sulfuric acid to remove sulfur and nitrogen compounds, to precipitate asphaltic

or gumlike materials, and to improve color and odor

2 Sweetening processes oxidize mercaptans to less odoriferous disulfides without

actually removing sulfur The most common sweetening processes are the Meroxprocesses; others include the lead sulfide, the hydrochloride, and the copperchloride processes In the Merox process, a catalyst composed of iron group metalchelates is used in an alkaline environment to promote the oxidation ofmercaptans to disulfides using air as a source of oxygen

3 Solvent extraction involves the use of a solvent that has an affinity for the

undesirable compounds and is easily separated from the product Mercaptansare extracted using a strong caustic solution The solvent is usually regenerated

by heat, steam stripping, or air blowing

Gas treating. This process is used to remove the sulfur compounds from the variousgaseous streams Hydrogen sulfide (H2S) can be extracted by an amine solution toproduce a concentrated stream of H2S that can be sent to a sulfur recovery plant

Treatment by physical means. Physical methods are intermediate steps in crude oilprocessing operations and are often used to treat hydrocarbon streams or removeundesirable components These methods include electrical coalescence, filtration,adsorption, and air blowing Physical methods are applied in desalting crude oil,removing wax, decolorizing lube oils, brightening diesel oil (to remove turbiditycaused by moisture), and other processes

Deposits and compliance assessment

Refineries are held to making reports on deposits and compliance assessment TableR-1 is a sample of this report for the Ontario region, Canada

Blending and additives

A number of intermediate streams, called base stocks, are blended to produce aproduct that will meet various specifications, e.g., specific volatility, viscosity, andoctane The blending operation involves the accurate proportioning of the basestocks along with proper mixing to produce a homogeneous product

A number of additives are used to improve the properties of the products Forexample, MMT is usually added to gasoline to increase the octane number sincerecent regulations forbid the use of lead in gasoline Other additives, such as anti-oxidants, anti-icing agents, and metal deactivators, are also used

Refineries, Petroleum R-5

TABLE R-1 Deposits and Compliance Assessment—Ontario Region

Refinery

A DEPOSITS (All guidelines and regulated deposits are for monthly averages.)

b) Number of monthly amounts

exceeding the limits by:

M, Monthly Amount; O, One-day Amount; D, Maximum Daily Amount

Glossary: Common Terms in the Refining Industry

Activated carbon Carbon that is specially treated to produce a very

large surface area and is used to adsorb undesirablesubstances

Actual deposits The amount of contaminants discharged in refinery

effluents

liquid, or a gas, when they are in contact

Aerobic bacteria Bacteria that require free oxygen to metabolize

nutrients

Air blowing The process used to produce asphalt by reacting

residual oil with air at moderately elevated temperatures

Altered refinery An existing refinery at which the primary crude oil

atmospheric distillation tower was replaced afterOctober 31, 1973

Refineries, Petroleum R-7

Deposits Deposits Deposits Deposits Esso, Novacor Deposits Deposits Deposits Deposits

Anti-icing additive A fuel additive used to minimize ice formation.Anti-knock compound Chemical compounds added to motor and aviation

gasolines to improve their performance and toreduce knock in spark-ignition engines

Antioxidants Chemicals added to products such as gasoline and

lubricating oil to inhibit oxidation

Authorized deposits The amount of contaminant to be discharged with

the effluent of a refinery as authorized by the federalRegulations and Guidelines

Blowdown Removal of liquid from a refinery vessel (storage or

process) through the use of pressure The term

“blowdown” is also used to refer to the actual liquidremoved

required by aerobic microorganisms to biodegradeorganic matters contained in wastewater The BODtest is used to measure the organic content ofwastewater and surface water

Catalyst A substance that promotes a chemical reaction

without itself being altered

equivalent of the organic matter required tocomplete chemical oxidation in an acidic medium.The COD test is used to measure the organic content

of wastewater and natural water

Cooling tower A large structure, usually wooden, in which atmospheric

air is circulated to cool water by evaporation

Existing refinery A refinery that began operation prior to November 1,

1973

Expanded refinery An existing refinery that has declared a revised

Reference Crude Rate of more than 115 percent ofthe initial Reference Crude Rate

Fractionator A cylindrical refining vessel where liquid feedstocks

are separated into various components or fractions

Landfill A location where solid waste is buried in layers of

earth in the ground for disposal

Leachate A solution resulting from the dissolving of soluble

material from soil or solid waste by the action ofpercolating water or rainfall

Liquid-liquid extraction The process whereby two immiscible liquids come

in contact to allow for the soluble material in thecarrier liquid to be extracted in the solvent

Maximum daily amount A limit set in the federal Regulations and Guidelines

for a number of parameters pertaining to refineryeffluents The refinery effluent should not exceedthis limit on any day of the month

Mercaptans A group of organosulfur compounds having the

general formula R-SH where “R” is a hydrocarbonradial such as CH3 and C2H5 Mercaptans havestrong, repulsive, garliclike odors and are found incrude oil.

Monthly amount A limit set in the federal Regulations and Guidelines

for a number of parameters pertaining to refineryeffluents This limit represents the amount thatshould not be exceeded in the refinery effluent on adaily average basis over each month

New refinery A refinery that has not commenced the processing of

crude oil prior to November 1, 1973

96-hour flow-through bioassay A test procedure required by the federal Guidelines to

evaluate the acute lethal toxicity of refinery effluent

to fish The procedure consists of exposing fish

to a continually renewed effluent under controlledconditions over a 96-hour period The percent mortality of fish is observed after the four-day period.96-hour static bioassay A test procedure similar to the 96-hour flow-through

method but in which the effluent is not renewedduring the period of test

Octane A number indicating the relative antiknock value of

a gasoline The higher the octane number, thegreater the antiknock quality

Once-through cooling water Water that has been circulated once through heat

exchangers in order to remove heat from processstreams without coming into contact with thestream

One-day amount A limit set in the federal Regulations and Guidelines

for a number of parameters pertaining to refineryeffluents Each refinery is allowed to exceed thislimit only once during a month

Ozonation Water treatment method that uses ozone as an

oxidant to remove pollutants, i.e., chemicalpollutants present in small concentrations that aredifficult to remove, or to disinfect water

Photosynthetic action A process by which organic compounds (mainly

carbohydrates) are synthesized by containing plant cells The reaction takes place inthe presence of light, carbon dioxide, and water.Priority pollutants A list of 129 toxic pollutants having known or

chlorophyll-suspected adverse effects on human health or theenvironment The United States EnvironmentalProtection Agency (USEPA) established this list and

has the mandate, under the Clean Water Act, to

control these pollutants in wastewater discharged tothe environment

Reference Crude Rate (RCR) The quantity of crude oil, expressed in 1000 m3/d,

declared by a refinery and used to calculate theauthorized deposits

Residual pitch A black, heavy residue produced in the processing of

crude oil

Sour water Water containing impurities, mainly sulfide and /or

ammonia, that make it extremely harmful

Refineries, Petroleum R-9