Multiple Effect Evaporator (MEE)

Effluent treatment for Strong Stream (for COD more than 10000 mg/lit):

The incoming effluent would be allowed to get collected in collection cum Equalization tank. Required chemical treatment would be given using for pH adjustment. The sludge from chemically treated effluent would be drained and the supernatant will pass through Multiple Effect Evaporator. The condensate from Multiple Effect Evaporator would be used in cooling tower of the quality is acceptable. The reject from MEE would be incinerated in Solid cum liquid incinerator.

The strong stream shall be given thermal treatment in Multiple Effect Evaporator (MEE). the required pre-treatment for separation of Suspended solids shall be as follows:

The strong stream shall be stored in one collection tank, the dosing of Poly Electrolyte for coagulation and settling shall be done in zig-zag channel and allowed to get settled in Settling tank. The supernatant of settling tank shall be fed to MEE for evaporation. The sludge separated at bottom shall be sent to TSDF site.

Tank size

Collection tank: 15 m3

Settling tank: 1.5 x 1.5 X 1.5 m3

INCINERATION SYSTEM:5.4.1 PROCESS DESCRIPTION:

Bogie type pyrolizer is stationary type and the solid waste is charged in batch wise into the bogie. The pyrolizer is operated at a temperature of 600 – 850 deg C and air is introduced in later stage for complete combustion of the waste.

The required auxiliary energy for incinerator temp is maintained by automatic fuel burner & is controlled through a temperature controller.

The aqueous waste is atomized through specially designed atomizer in to the ma in combustion chamber . The temperature of the MCC is maintained at 800 – 900 deg C. Required energy for incinerator temp is maintained through fuel burner, which is controlled through temperatures controller for better fuel efficiency.

Post combustion chamber is refractory lined fired furnace. Fuel burner is installed in the chamber to supplement required energy to raise the temperature of the gas stream to achieve complete destruction of

combustible components or to enhance conversion of the components. The flue gas from Bogie type pyroliser & MCC is re-combusted in the combustion chamber at 1100 - 1200°C in excess air condition and required retention time. Air is provided to the chamber to achieve complete destruction.

Quencher is a n o pe n c o lu m n d i r e c t c o n t ac t c o un t e r cu r rent hea t exchanger. Gas is introduced from the bottom and move upwards while the water i s in jec ted f rom top a tomized drop le ts . When the water evaporates, the heat of vaporizing the water is obtained at the expense of the hot combustion gas, resulting in a reduction in the gas temperature. The un-vaporized water reaching the bottom of the tower is re-circulated by pumping back to the Quencher. The quencher is considered as spray tower and spraying of water droplets in to a polluted gas stream resulting in the removal of highly soluble gases and particulate matters. The evaporative loss of water from the circulation tank is compensated by makeup water addition. This alters the particulate properties by raising surface conduction and increasinginter-particle bonding, thereby enhancing the co l lec t ion o f dust and trace elements in part iculate devices.

The cooled flue gases from quencher are then passed through a Venturi. Venturi is a pressure jet type device. Incinerator exhaust gas entering in to the Venturi is accelerated to high velocity at the constricted area (throat) and the scrubbing liquid is introduced at the throat in fine form. The high velocity of the gas causes breaking of droplets into fine filaments and droplets, which allow a large surface area.

The droplets accelerate in the throat section and the droplets and particles are impacted against the slow moving droplets. Venturi itself is only a gas conditioner and is followed by a separator. The liquid gas mixture is their directed to separator to separate dense wet particles and liquid droplets in the gas stream.

Packed Bed Scrubber is vessel filled with randomly oriented packings, Ranching Rings. Gaseous contaminants are removed by gas absorption process by intimate gas/liquid contact. The Scrubbing liquid is fed into the top of the vessel, with gas flowing in counter current mode. As the liquid flows through the bed, it wets the packing material and provides interfacial surface area for mass transfer with the gas phase.

On the Packed Bed Scrubber, the scrubbing liquid (NaOH Solution) wets the gas rise through the column making close contact with the down flowing liquid little gas. The soluble gases are scrubbed from the mixture of gases by liquid. In the absorption of gases, caustic soda reacts directly with gases as the gas approaches the liquid interface it dissolves and reacts with caustic soda.

The support plate at the bottom of the bed of packing is designed to have least resistance and maximum flow area and to have better distribution of gas across packing bed and draining liquid completely.

The distributor mounted on top of the packed bed is designed to provide uniform –irrigation of the packing.

Flue gas from the packed bed scrubber is passed through mist eliminator for mist removal and flue gases are released into the atmosphere through an I.D. Fan & Chimney.

I.D. Fan is the heart of the system, which maintains draft in the system to overcome the flow resistance & prevent obnoxious gas leakage in the plant operating area.

The system is provided with chimney to discharge the gas with good dispersion characteristics.

5.4.2 INCINERATOR PROCESS FLOW DIAGRAM:

5.4.3 DESIGN ADEQUACY OF INCINERATOR :

Sr.No.

Incineration Aspect Design Remark

1 Incinerator capacity Solid waste – 50 Kg/hr, Aqueous waste – 250 lit/hr --2 Characteristics of Waste

Aqueous Waste 75% Water, 3-5% Organic, 10-20% inorganic salt, Calorific Value-300 Kcal/kg

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Solid Waste Activated Carbon/Organic sludge/Packing material etc., Calorific Value-4000 Kcal/kg

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3 Storage of Hazardous Waste 3 MT --4 Waste feeding system

Solid waste feeding Bogie type pyroliser for incinerating solid waste. Solid waste will be fed in the bogie batchwise.

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Aqueous Waste feeding Aqueous waste is fed through specially designed automizers into the main combustion chamber.

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5 Primary Chamber             

Type : On/OFF type, monoblock AdequateSize -2200 mm dia X4000 mm longVolume : 6 m3

Type of fuel : LDO/HSDFuel consumption rate : 40-50 ltr per hourFuel calorific value : 9600 Kcal/kgTemp. : 800 – 9000C Refractory lining : 115mm thk – Insulation Brick 230mm thk – Fire Brick Burner details:Make : Mc CellendNos of burners : Burner cap.: 20-60 X10 4– MCC

ADEQUECY OF INCINERATOR :

Sr.No.

Incineration Aspect Design Remark

Blower Details: AdequateNo. of Blowers : 1 (common for MCC, PCC and Bogie

Pyroliserl)Capacity of Waste Blower : 2500 m3/hr 5 HP

5 Secondary Combustion Chamber(Proposed)

Temperature : 1100 – 12000C AdequateMOC : MS + Refractory lined

Refractory : 50 mm thk – calcium Silicate blocks

115mm thk – Insulation rick 230mm thk – Fire Brick

Burner Details:No of Burner : 1, ON/OFF type, monoblockBurner Capacity : 30 X 104 - PCCBlower Details:No. of Blowers : 1 (common for all)Capacity of Waste Blower : 2500 m3/hr 5 HP X 2900 RPMFuel DetailsType of Fuel : LDO/HSDFuel Consumption Rate : : 20-30 ltr per hrFuel Storage Capacity : 20000 Lit.Shell Volume:Shell Inside Volume: 9 m3

Size: 2600 mm dia X 4600 mmResidence Time : min. 2.5 sec

ADEQUECY OF INCINERATOR :

Sr.No.

Incineration Aspect

Design proposed Remark

6 Pollution control devices

Type pollutants expected: - HCl/ SO2/ NOx/ particulate matter AdequateStack Details:Stack Height : 30mTop dia. : 550 mmFlue gas temp. : : 70-750C Reservoir / Quenching tank:Size : 0.6 m dia X 0.9 m heightType : CYLINDRICALVolume : 5000 Lit.MOC : PP/FRPVentury Scrubber: AdequateType : Pressure jet venturiThroat Venturi Dia : 300 mmMOC of Venturi : MS + RefractoryRefractory : Acid resistance bricksPressure drop : 250--350 mmwcVentury water tank : 3 m. X 3 m. X 5 m.ID Fan: AdequateFan type : induced draft ,Centrifugal, 2 Nos.Fan cap. : 9000 m3/hr & 650mm water gauge pressureMotor HP : 50HP

ADEQUECY OF INCINERATOR :

Sr.No.

Particulars Design proposed Remark

6 Pollution control devices

Packed Bed Scrubber: AdequateOverall size of PBS : 2000 mm dia X 5500 mmM.O.C : MS internally refractory linedPressure drop : 100-115 mmwc

Packing : 1 ½” rashing ringsPacking height : 1000 mm +400 mmScrubbing media : Water + CausticScrubbing temp : 70-750CCirculation Tank : 5 M3Circulation tank : MS internally refractory linedNozzle MOC : SS316LCirculation Pump : Type-Vertical glandless

Capacity-20 m3/hr, MOC- PP, Motor-7.5 HPPressure--2 kg/cm2

7 Ash/slag management

Collection, storage, transportation by registered vehicles and final disposal to Approved TSDF site. Storage area 3.0 m X 3.0 m shed of 4.0 m height

Adequate

8 Monitoring and online display requirement

Stack gas monitoring/recording system for CO/SO2/NOx / HCl/ Opacity Adequate

9 Quench / scrubber liquid Management

Quencher /Scrubber effluent can will be sent to effluent treatment plant for further treatment.

Adequate