Symp-Gotovtsev

7/27/2019 Symp-Gotovtsev

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Water at thermal power plants

Requirements:Desalinated water for boilers feeding;

River or sea water for condensers cooling;

Soft water for district heating systems;

other technical needs.

Water treatment systems:

Water desalination system;

Water-steam cycle systems (dosing systems, condensate polishers);

Cooling water treatment systems (correlated with water characteristics);

Water softening system for district heating systems.


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Waste water problems

water purification system that produce ultrapure water for the boilers feeding; this

system also have two types of waste water: water with high mineralization and water

with sludge after coagulation;

cooling systems with wet cooling towers: in this system water cooled in thetowers is used for steam turbines condensers cooling; the difficulties in this systemrelated with blowdown that have from 2 to 5 times higher concentration of impurities

in comparison with water source;

water with oil; there are a lot of oil contained systems at power plants and in some

cases this oil mixtures with water;

rain water from power plant territory also can contain oil and some specific

impurities related with technological processes, for example coal dust in the coalfired power plants;

and many others


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Water management

Initial steps:

Determination of treated water demand;

Determination of water availability and quality in water

source;

Determination of possibility of water discharges and

requirements of waste water quality;

In case of existing power plant:

Determination of all waste water streams in power plant;

Determination of impurities concentrations in the each wastewater stream;


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Water management

Chemistry control of all water streams in power plant

Main on-line instrumentation (depending of waste water source):

pH;

Conductivity;

Turbidity;

Oil;

Additional:

Fe and Cu;

Ammonia;

TOC


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Water intake

Cooling system

Rain and meltwater

Water treatment

(make up)

Sludging

Sludge dump

Steam cycle

Neutralizing site

Waste water treatmentsystem Permanent

discharge

7 Drainagetreatment

Industrial heatingsystem

Oil in

water

3

8

1

10

Discharge

chemicals

9

4

controller users

2 3 4 5 61

2

6

5

9

10

7

8

pHpH

turbidity

turbidity

Oil in

water turbidity

pH

conductivity

conductivitypH conductivity

On-line chemistry control

Example of on-line

chemistry control a

combine cycle poweplant with coolinsystem with coolintowers


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Water reuse

Previous slide powe

plant. Reuse of rainwater and water with

oil.

This system gives 55

m3/h periodical

additional makeup incooling system.

But its means around170 000 m3/yeareconomy of water

from source and the

same number ofdecreasing of

discharges.


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Water reuseThe same power plant. Membrane water treatment.


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Water with high mineralizationTreatment of RO concentrate or water after regeneration of ion-exchange filters is

the main challenge in zero-liquid discharge projects


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Cooling system with wet cooling

towers blowdown

Main problems:

High concentration of impurities in comparison with water in the water

source;

Corrosion, biocorrosion and scaling;

Volume of blowdown in some cases exceed water requirements ofpower plant.

Using blowdown as a water for water treatment system.+ all or part of blowdown is reusing;- large impurities load on water treatment unit (rising of regeneration

number or impurities concentrations in concentrate in case of ROsystem).


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Some challenges in zero-liquid

discharge power plants

1) Sediment and sludge problem. Utilization of all sludge and sediment is veryexpensive. There are exist technologies of partial re-use of salts with producingsulfuric acid or NaCl.

2) Mixing problem. We have to mix different types of treated water with waterfrom water source.

In IGCC and combine cycle water consumption is very low, in several regions therain and melt water sometimes will be around 20-50% of water that goes to thetreatment. Those waters have very high differences of concentrations of impuritiesin very short time (during one rain or during snow melting periods).


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How we cane increase of water reuse

systems efficiency?

Water from flue gases technology this technology can decrease waterconsumption.

New chemicals for example, we use polyacrylamide (PAA) based chemicals forflocculation, is there any new hydrophilic polymer that can improve efficiency ofsedimentation and help with additional treatment of sludge (dewatering and

utilization)?New floaters already have a very good efficiency. However it is possible to expect

some increasing of efficiency due to new technologies of water-air mixing withlow volume of air bubble.


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Thank you

any questions

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