xử lý môi trường ở nhà máy lọc dầu dung quất

• Cleaner production— prevention, redesign Changing fuel, removal pollutant from raw material  Changing technologies  Increasing inspection and maintenance  Operating procedures — pr

Integrated environmental management

in Dung Quat refinery

Priority for environmental management

1 Reduce

2 Reuse

4 Final Treatment

Waste Raw material

• Using efficient energy

Air pollution control

Source of emissions

– Pollutants discharged from 11 stacks ofrefinery including SO2, NOx, CO, HC…– Dust generated from transportationactivities within refinery

– Leakage, fugitive emission from tank,pipeline and equipment vents

– Heat and radiation from units, fire heaterand flare

– Noise and vibration from power plant androtating equipments

Air pollution control

• Cleaner production— prevention, redesign

 Changing fuel, removal pollutant from raw

material

 Changing technologies

 Increasing inspection and maintenance

 Operating procedures — production

coordination

• Recycle

• End-of-Pipe control

Particles control devices

Gaseous pollutants control devices

Approaches to Emission Control

PROCESS

Cleaner production

Control Devices

Reduced emission

Cleaner production

Control DevicesAir pollution control

Cleaner production (treatment at the source)

• Remove H2S out of gas (Gas Plant, LTU)

(C2H4ỌH)2NH (DEA) +H2S  (C2H4OH)2NH2HS

• Remove S out of raw material (NHT, LCO hydrotreater Unit) S+H2=H2S

• Purpose : - Catalyst protection

– Improve quality of product  Protection of Environment

• Amine regeneration :

(C2H4OH)2NH2HS  (C2H4OH)2NH + H2S

SRU

Recycle back to absorption units

Air pollution control

• Treatment of gas streams (rich H2S) from unit ARU, CNU,

• Sulfur Recovery from H2S gas stream

Air pollution control

Cleaner production (treatment at the source)

End of Pipe control

• Particle matter (PM) control

• Cyclones are used to control PM, and primarily PM greater than 10 micrometers

• Particle matter control

– Electrostatic Precipitator (ESP)

Gas stream from regenerator of RFCC containing high concentration of PM (1200mg/m3) whereas environmental standard (TCVN 5939-1995) is 400 mg/m3

Using ESP to remove PM to meet standard Advantages of ESP

• High collection efficiency (99÷%)

• Treats large volumes of gas

• Produces only low pressure drops

• Economical to operate

• Offers dry collection of valuable products

• Generates dry waste for disposal or recycle

End of Pipe control

MTC

Discharge electrodes

Flue gas in

Clean gas out

Hoppers

Rappers

ESP

Electrostatic Precipitator (ESP)

End of Pipe control

Air pollution control of RFCC unit

• Control SOx (DeSOx)

SOx formed when burning oil or gas containing S

S + O2 = SO2

– When processing BachHo crude oil, SO2 in emission from Dung Quat refinery is lower than TCVN 5939-1995 (500mg/Nm3) Removal of SO2 is not necessary

– When processing sour crude oil or TCVN is more stringent, it is required to equip SO2 control devices

End of Pipe control

• Control SOx (DeSOx)

Using Ca(OH)2, NaOH, Mg(OH)2, CaCO3 to absorb SO2, the reaction as follow:

– SO2 + Ca(OH)2 + H2O => CaSO3.1/2H2O + 3/2H2O

– CaSO3.1/2H2O + 3/2H2O + 1/2O2 => CaSO4.2 H2O

– SO2 + CaCO3 + 1/2 H2O => CaSO3.1/2H2O (Oxidation

to CaSO4.2H2O)+ CO2

–

End of Pipe control

Make-up water

Recirculation tank

Pump

Feeder

Alkaline storage tank

Treated liquid Purge

liquid

Recirculation liquid

Mist eliminator spray water

Exhaust to atmosphere

Inlet gas stream

• Formation of NOx from air Nitrogen

– NO increases with T°C, significant at >700°C

– NOx in flue gas: 500-1000 ppm (90% NO + 10% NO2)

• Concentration of NOx of flue gas in Dung Quat refinery is lower than TCVN 5939-1995 (1000mg/Nm3), treatment of this gas is not required.

• But when standard is more stringent, treatment may be required

Control NOx

• Pre-combustion:

– Fuel choice: fuel gas

– NOx emission >oil>fuel gas

• During combustion: low NOx burner (for air N2)

– Important comb factors & design for NOx control

• Combustion temp control: avoid high peak T°C; Avoid high heat release & achieve high heat removal; Minimize residence of mixture time at high temp zone

• Extend of combustion-zone cooling of primary flame zone (heat transfer to surrounding > heat removal)

• Furnace configuration: firing methods for heat removal (tangential firing reduces NOx by 50-60%)

– Combustion modification techniques

• Flue-gas recirculation: portion of cooled gas injected into combustion zone => reduce T°C & O2

• Two-stage or off-stoichiometric combustion: First stage: air — 85-95% of stoich => reducing env => O2 & low temp => low NOx

2 stage: inject secondary air downstream oxidize at lower T°C downstream > low NOx

Control NOx

• Post-combustion: DeNOx

– Selective catalytic reduction (SCR):

Reactant (CO, NH3 etc.) selectively react with NOx in presence ofcatalyst => reduces NOx to N2 and O2

CO as reducing agent, Pt catalyst reaction as follow:

2CO + 2NO = CO2 +N24CO + 2NO2= 4CO2 + N2– Selective non-catalytic reduction (SNCR):

Injection of reactants (NH3 or urea based compounds) with high To

(optimum: 930-1090oC ) => high activation, no need catalyst

Reactant: NH3

4NH3 + 6NO = 5N2 + 6H2O

Control NOx

Typical process flow diagram for removal of NOx using SCR

Control NOx

Wastewater Management

Segregation of effluent streams

• Importance of segregation of the waste water into different streams:

– For reduce, reuse and recycle Each stream is

characterized with different properties

– For applying different methods of treatment

– Some streams required to treat, the other are not required to meet TCVN 5945-1995

Classification of effluent streams

• The typical sources of effluent streams in Dung Quat Refinery are:

– One through cooling water

– Storm water

– Oily Surface Water (OWS)

– Oily Water (OW)

– Stripped Sour Water (high concentration of phenol)

Management of wastewater

• One through cooling water

– Properties:

• Seawater

• For cooling of fresh water

• Outlet is 8oC higher than inlet

• Biocide injected (HOCl3)

5945

Monitoring

• Temperature

• Residue Chlorine

Raining water

SEA

50mm of raining water

CPI

Management of wastewater

OWS comprises surface water run-off from areas that are at risk

of hydrocarbon contamination as a result of spillage or

malfunction Normally, any contamination would be light and

amenable to basic treatment.

OWS comprises water run-off from:

– paved process areas

– specific bunded / kerbed areas

– truck and tanker loading / unloading areas

The following utility effluents are also classed as OWS:

– freshwater filters (backwash)

– neutralised effluent from demineralisation plant

– condensate recovery system filters (backwash)

– fresh cooling water system purge and drain

Management of wastewater

• Oily Surface Water (OWS)

•Stripped Sour Water (SSW)

– Properties:

Phenol: 258mg/L

– Treatment (Primary treatment)

Due to the high phenol content in this stream and the stringent standardimposed on phenol residuals (0.05mg/L), it is treated by activated sludgetreatment after cooling and coagulation step The pre-treated effluent isdirected to balancing tank

Heat exchanger

Return sludge

BALANCE TANK

Excess sludge

to thickener

Biological treatment

Chemicals

Clarifier SSW

Management of wastewater

OWS

OW comprises aqueous effluents that are continuously contaminated.Typical sources of OW include, but are not limited to:

– miscellaneous process effluents and vessel drains

– water from CDU desalter

– neutralised spent caustics

– water from flare seal drum

– crude oil tank drainings

– slops oil tank drainings

– equipment cleaning areas

Heat exchanger

Return sludge

BALANCE TANK

BASIN

CPI Screening

DAF

Excess sludge

Biological treatment

Chemicals

Aeration digestion

Thickener

Sand Filter Clarifier

Sludge farm

SEA

Management of wastewater

OW

Environmental Monitoring

As required, the in-plant emissions (in air and water) shall be monitored on a daily basis to verify the compliance with the relevant TCVN In the REFINERY, the emissions come from:

– Heaters and Boilers stacks

– Flares

– Refinery ETP

– Product tankage ETP

– Storm water outfall

– VOC fugitive emissions

• Oily Water (OW)

– The stack emissions shall be monitored to verify the compliance ofthe exhaust gases composition with the TCVN 5939-1995: AirQuality, Industrial Emissions Standard for Inorganic Substancesand TCVN 5940-1995: Air Quality, Industrial Emission Standardfor Organic Substances.

– The following contaminants shall be monitored:

– SO2– NOx– CO– H2S– HC– VOC, Dust…

Comply with TCVN 5939/5940-1995

Environmental Monitoring

• Air quality monitoring

Environmental Monitoring

– The treated effluents from the Refinery and the product tankageETPs shall be monitored to verify the compliance with the TCVN5945-1995: Industrial wastewater - Standard for discharge

– The following parameters shall be analyzed daily:

– Temperature– PH

– DO– COD– BOD5– TSS, TOC, Phenol, Total N, Total P…

Environmental Monitoring

• Air quality monitoring

Refinery environment monitoring

As required in the DEIA, the REFINERY environment (air, surfacewater, sea water, ground water, offshore sediment, soil) shall bemonitored twice a year to evaluate the impact of the REFINERY on theEnvironment and compare the ambient air and natural waters quality.The following parameters shall be analysed:

– Air: SO2, NOx, CO, H2S, VOC, Dust, O3

– Sea Water and surface water: Temperature, PH, DO, COD, BOD5,

TSS, NO3, Total N, Total P, SO4, TOC, Phenol, Metals (Hg, Cd, Zn, Ba,

Mn, Ca, Mg, Cu, Pb, Cr, Fe, As, Ni)

– Offshore sediments: Hydrocarbons, Metals (Hg, Cd, Zn)

– Soil: Hydrocarbons, Metals (Hg, Cd, Zn)

– Ground water: PH, TSS, Cl, SO4, CN, NO3, Phenol, TOC, metals (Hg,

Cd, Zn)

– Biology: Benthos, Phytoplankton, zooplankton

Locations for Refinery Environment Monitoring is indicated in next slide

Locations for Refinery Environment Monitoring

Waste Management

• Hazardous waste, non hazardous waste

– Waste lead acid accumulators

– Used activated coal

– Clinical and related wastes

• Non-hazardous waste

Types of waste generated in DQR

– Plastic materials or plastic mixtures

– Waste paper, paperboard and paper Products

– Wastes from the farm product processing industry – Domestic wastes

– Used activated coal from the potable water

treatment

• Other catalyst will be returned to manufactures/suppliers

to recover the valuable metal such as Platinum

• Used activated coal from KTU, ETP (Unit 52): Will be directly removed this waste from site for regeneration

Cement or asphalt for road base

Landfill

Waste Management

• Hazardous waste

Waste Management

• Hazardous waste

In DQR, there is temporary hazardous waste storage It is used to

stored temporarily hazardous waste before transporting outside

- Waste mineral oil

- Chemical waste

- Waste lead acid accumulators

Will be temporarily stored

third party for furthertreatment

– Clinical and related wastes

 Produced in the medical centre

 Collected from individual bins on a daily basis

 Stored in dedicated containers located inside the medical centre

 They will be collected twice a week and sent for incineration atthe Dung Quat Economic Zone incinerator

Temporary hazardous waste storage within Refinery

Waste Management

Non-hazardous wastes will be temporarily stored nearby their production location until they are transported outside the refinery for final disposal

– Waste paper, paperboard and paper products

They will be stored in bins

or skips They are transported outside once a month and sold for recycling.

Will be sold as fertilizer for land reclamation.