Seminar

7/21/2019 Seminar

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WASTE WATER TREATMENT

IN REFINERIES

Presented By:-

Joy Raval

7/21/2019 Seminar


Introduction

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REFINING PROCESS

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• Petroleum industry, have had considerable role ingeneration and release of waste materials into theenvironment.

• A variety of waste products are produced in reneries ingaseous, liquid and solid phases, which must be treatedand disposed in an environmentally friendly manner.

• Production, rening and conversion of crude oil to usefulchemicals are associated with direct or indirect release ofwaste materials and pollutants into the environment.

• Water consumption in oil reneries is huge and so is thewastewater generation.

• Crude oil contains small amount of water solublecompounds, but Water and hydrocarbons are basicallyimmiscible which makes wastewater treatment operationsa challenge.

• il reneries are under immense pressure to comply withthe new rules and regulations related to environmentprotection and operation safety

• !espite regular generation of wastes, there are inevitablerelease of pollutants in reneries due to malfunctioning ofthe units, pump leakage, erosion, corrosion, pipeline failure,

etc.

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• "hese contaminants are highly mobile and can easily travel distances by di#erent

mechanisms through air, soil and underground water.

• Contamination may be in the form of free phase product $e.g. liquid or vapor%,dissolved products, or emulsied phase.

• n the other hand physical, chemical properties of water and soil will be a#ected,

which results in shifting ecological equilibrium in damaged areas.

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Ultimate fate of refinery wastes

• "he primary processes determining the fate of wastematerials in an oil renery may be summari&ed as'

• !ispersion in air and water

• !issolution in water• (mulsication

• )edimentation

• Adsorption*absorption

• )preading

"he waste materials may undergo some of theseprocesses simultaneously.

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Wastewater treatment• Waste waters from petroleum rening consist of cooling water, process

water, storm water, and sanitary sewage water.

• A large portion of water used in petroleum rening is used for cooling$may contain hydrocarbons due to leakage%.

• Process wastewater is usually highly contaminated depending on theprocess.

• )torm water $i.e., surface water runo#% is intermittent and will containconstituents from spills to the surface, leaks in the equipment and anymaterials that may have collected in drains.

• +uno# surface water also includes water coming from crude andproduct storage tank roof drains.

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Wastewater treatment• Waste waters are treated in onsite wastewater treatment facilities

and then discharged to publicly owned treatment works $P"Ws%or discharged to surfaces waters under ational Pollution!ischarge (limination )ystem $P!()% permits.

• -t is essential not to mi wastewaters from di#erent processes as it

may complicate the treatment process, unless they have similarproperties.

• Petroleum reneries typically utili&e primary and secondarywastewater treatment.

• Wastewater treatment plants are a signicant source of renery airemissions and solid wastes.

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•Pieces of equipment that remove oil3oating on the surface of a 3uid. -ngeneral, oil skimmers work because theyare made of materials to which oil is morelikely to stick than the 3uid it is 3oating on.

•Pre4treating the 3uid with oil skimmers

reduces the overall cost of cleaning theliquid.

•All designs depend on the laws of gravity and on surface tension in order to function.

"he si primary types of oil skimmers arebelt, disk, drum or barrel style, mop, largetube or mini tube, and 3oating suction oilskimmers.

http://www.wisegeek.com/what-is-gravity.htm

http://www.wisegeek.com/what-is-gravity.htm

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• "hey are provided $i% to balance 3uctuating 3ows orconcentrations, $ii% to assist self neutrali&ation, or $iii% to even outthe e#ect of a periodic 8slug8 discharge from a batch process.

• Types of Equalization Tanks

• 9low through type 4 useful in assisting self neutrali&ation. A 3owthrough type tank once lled, gives output equal to input.

• -ntermittent 3ow type4 9low balancing and self4neutrali&ation areboth achieved by using two tanks, intermittently one after another.

• :ariable in3ow*constant discharge type4 When 3ows are large anequali&ation tank of such a si&e may have to be provided thatinfow can be variable while outfow is at a constant rate

.

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•An aeration tank is a place where a liquid is heldin order to increase the amount of air within it.

• "here are two main methods of aerating liquid'forcing air through the liquid or forcing liquidthrough the air.

• "he water is mied with biological agents andthen aerated. "he increased oygen promotes thegrowth of the benecial biological material. "hatmaterial will consume unwanted waste productsheld in the water. "he benecial material will growdue to the increased oygen and food, whichmakes it easier to lter from the clean water.

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•)ometimes reneries have lagoons or nalpolishing ponds.

•Types of aerated lagoons or basins

•)uspension mied lagoons, where there issu<cient energy provided by the aerationequipment to keep the sludge in suspension.

•9aculative lagoons, where there isinsu<cient energy provided by the aerationequipment to keep the sludge in suspensionand solids settle to the lagoon 3oor. "hebiodegradable solids in the settled sludge

then degrade anaerobically.

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• The treated water should have the maximum limits of the following

• BOD (Biologial Oxygen Demand! - "# mg$l (%& day average!

- '# mg$l ( day average!

• T)) (Total )us*ended )olids! -%& mg$l (%& day average!

- '# mg$l ( day average!

• *+ shall remain ,etween .& and /.&

• 0n addition1 there shall ,e no visi,le solids and$or visi,le oil or greases in the disharge.

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• Abadi et al., !esalination, :olume =>?,=@,pp.

===4==B

• A.1. et al., Chem. (ng. ., :olume B, =@@>, pp.DD4@?

• 1in et al.,-nd. Water "reat., :olume =>, =@@>, pp.

?4B

• )chol& and 9uchs, Water +es., :olume EF, =@@@,pp. E>=4E>?B

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