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Cooling towers SK-400, SK-1200

 

Engineering. Cooling towers SK-400, SK-1200

 
For chemical and petrochemical enterprises of the countries of the former USSR, widespread specially developed modification of the round mechanical-draft cooling tower with irrigation area of 400 m2 (SK-400) and 1200 m2 (SK-1200).
 
Advantages of cooling towers of this type are:
 
  • large single productivity, which can reduce occupied area on the premises;
  • a small length of water supply lines;
  • possibility of use in harsh climatic conditions;
  • increased, in comparison with the tower cooling towers, resistance to strong winds;
  • frost resistance, thanks to the ability to turn off fans to reduce cravings;
  • control of cooling capacity by changing the rod;
  • easy installation and ease of repair.
 
The design of these types of cooling towers include cast-concrete or metal skeleton of cylindrical form with height of 9 and 10 meters, a base diameter of 24 and 36 meters, respectively.
 
  
The fan casing is of elliptical shape made of steel. The impeller is made of aluminium / steel.
There are two options for placing the driven equipment: the lower the gear drive, the upper gear drive.
 
Lower gear drive involves the placement of e/d, and the angular reducer of the type in the engine room under the tower.
 
Torque is transmitted to the impeller via a system of vertical steel shafts passing through the shaft of the tower.
 
The layout of the drive equipment is associated with the increased load on the thrust bearing of reducer and steel drive shafts.
Top gear drive involves the placement of e/d, the transmission shaft and reducer angle-type at the level of the fan impeller on a supporting structure outside the fan casing.
Most cooling towers data series was constructed more than 20 years ago, so the question of their overhaul / modernization is important.
 
 
The complex of works typically includes:
  •  replacement of the driven equipment (e/e, gearbox, drive shafts, transmission couplings);
  •  replacement of ventilation equipment (impeller, fan stack);
  •  replacement of water distribution systems (headers, injectors);
  •  replacement of drift eliminators;
  •  replacement of cooling fills;
  •  replacement grounds maintenance / equipment placing;
  •  the installation process control system (including a separate hermetically sealed unit-box with translation of the operating voltage from 6000 V To 380 V).
 
Selection criteria of the equipment are the use of modern materials, resistant to corrosion, increased productivity, introduction of modern means of automation and control, energy saving. Typically, the reconstruction allows to increase cooling tower performance by 30-40%, reduce energy consumption by 25-30%, extend the life of cooling towers at 20-25 years.
 
The average technical characteristics of cooling towers SK-400 or SK-1200 after reconstruction

Parameter

Unit

SK-400
SK-1200
   Volume flow
m3/h
3000 - 4500
12000 - 18000
   Heat load

MWt

42 - 63
168 - 252
Diameter of section
m
24
36
   Тmax inlet water

oС

36 - 37

36 - 37

   Tmin оcooled water
oС
24 - 25
24 - 25
   Diameter of the fan
мм
10400
20000
  Drive power
kWt
up to 250
up to 800
 

 

Technologies

Fan impellers WTR

In 2009, the company AKVANN mastered the production of impellers of the fans of the brand of WTR composite materials reinforced with fiberglass. Taking into account the most modern achievements of world leaders in this field, we have designed a line of impellers that are responsive to the needs of the consumer from the point of view of technical, operational and noise characteristics.

РК WTR 10400   РК WTR 10400   РК WTR 10400

Impeller stamps WTR may have a diameter of up to 20000 mm and the number of blades from 3 to 8. Possible to use 3 different variants of the profile of the impeller, as well as several variants of external protective coating: antistatic, antacid/protivosokowoe, self-extinguishing, high temperature/low temperature.

Before installing the cooling tower by a dynamic balancing of the impeller Assembly with the hub in 2 planes according to standard ISO 1940-1-2007. All impellers are provided with the quality certificate of manufacturer, certificate of industrial safety of the Russian Federation. If necessary, the impeller can be manufactured in explosion-proof execution.

The fan stack ADW for cooling towers SK-400, SK-1200

Currently for cooling towers SK-400 AKVANN company has developed and produced the fan casing is made of fiberglass ADW 10400x11140.

Корпус ADW 10400x11140. Монтаж   Корпус ADW 10400x11140. Монтаж   Корпус ADW 10400x11140. Монтаж

The fan stack has a confuser and diffuser parts and is a self-supporting structure with a base diameter - 20 000 mm, height - 15 000 mm, weight of just 11 tonnes. For comparison, metal body with internal supporting structures weigh about 30 tons. The lack of inside self-supporting body of the supporting structures reduces the thermal resistance of the cooling tower to increase cooling.

This housing type is installed on the cooling tower SK-1200.

Cooling fills

Is one of the main structural elements of the cooling tower, defining its cooling ability. The cooling fills design must provide sufficient surface area to cool with optimal aerodynamic resistance.

Taken into account and a number of other factors, the durability of the material of the cooling fills in the environment of use, durability, weight, ease of installation and maintenance, as well as the presence in water of suspended solids and corrosive contaminants. The choice of sprinkler is done on the basis of the thermal calculation, taking into account the performance of the material.
 

Drift eliminators

Depending on the airflow rate, size of water drifting, the operating environment, used two version of drift eliminators type "wave" with a height of 185 mm slats, and meshed drift eliminators with horizontally oriented tubes.
Водоуловитель типа Полуволна    
Drift eliminator type "wave"
Drift eliminator of PVC / fiberglass, bonded fastening elements from polypropylene.
Height 185 mm lamella, distance between lamellas 40 / 50 mm.
Nominal drop ablation: 0.001-0.003 % / 0.003-0.004 %. Flow rate 1.0-3.0 m/s.
Водоуловитель сетчатый Meshed drift eliminators
Drift eliminator polymer horizontal latticed shells with a diameter of 45 mm, placed in 3 layers in parallel to each other. Material: HDPE 273-79, stable carbon.
Height 130 mm. nominal drip ash: 0.04 %. The flow velocity of 2.0-3.0 m/c.
The water distribution system (WDS)

Consists of a main manifold and a peripheral outlet manifold. An important factor in the choice of structural material for the WDS is the corrosion resistance in the operating environment, strength characteristics and weight.

Система водораспределения    
Used 2 versions of VRS:
• Main collector – fiberglass, peripheral reservoirs – polyethylene;
• Main collector – fiberglass, peripheral collectors – fiberglass;
On request it is possible production version of the collectors of steel with corrosion-resistant coating.

Spray nozzles

Priorities when choosing spray nozzles is the optimal combination of the following parameters: operating point (flow rate – working pressure), corrosion resistance, ease of installation and replacement life.

In addition, should be provided with the longest maintenance interval because the maintenance of WDS, for objective reasons, is difficult.
Based on these factors, in cooling towers SK-400, SK-1200 applies low-pressure spray nozzle.

Форсунка УПП    

Spray nozzle UPP

The diameter of external thread 2“.
The diameters of the through hole 37 mm (UPP №1) и 30 mm (UPP №2).
Диапазон применяемых расходов от 3.2 м3/ч до 10.5 м3/ч в диапазоне рабочих давлений 0.1-0.4 м.в.с. Усредненная площадь орошения 1 м2.

The range of flow rates is 3.2 m3/h to 10.5 m3/h in the range of operating pressures 0.01-0.04 bar. Average irrigation area of 1 m2.

Water treatment

Is designed to bring the chemical composition of recycled water in accordance with the technical norms for the correct operation of cooling towers and technological equipment of water circulation circuit.

Significant loss of water by evaporation, particularly in summer operation, cooling towers – up to 3% per hour increase in circulating water concentration of hardness salts. Salt deposits adversely affect the distribution system, the spray nozzles, the corrosiveness of the coolant increases as well.

Effective solution of this problem are demineralisers installation on ion-exchange resins and anticorrosive agents. To prevent the growth of biological microorganisms, the system adds the chemicals-biocides.

Usually the high Flow rate of water in cooling towers SK-400, SK-1200, water treatment system usually are placed in a separate specially equipped room. Also produced mechanical water filtration from the insoluble substances.

 

Automation
 

Typically, the selection of the cooling tower, is made for the hottest period of the year - 3 summer months. During this period, the cooling tower is operating at maximum capacity. The rest of the time max laid resource productivity leads to a waste of energy.

The lack of control in the autumn-spring period of operation also leads to disruption of the stability of the cooling water with a "cold" start-up of equipment and, as a consequence, the early wearing of its resources.

To prevent accidents or damage of expensive drive technology, automatic control system of the cooling tower is equipped with necessary systems of monitoring, to track, to warn of malfunctions and, if necessary, to stop the operation of the cooling tower, preventing critical consequences.

Operation of cooling towers in explosive surroundings without the automatic control system is also impossible.

In this regard, we can formulate the main purposes of automation of cooling towers:

  • stability of cooling process;
  • reducing energy consumption;
  • reliable operation in cold operation period;
  • safety of equipment and personnel;
  • remote monitoring and control;
  • reducing the influence of human factor on technological process;
  • аutomation of cooling tower SK-400, SK-1200 in the basic version includes a monitoring / control:
  • temperature input and output of water,
  • the ambient air temperature,
  • the vibration of the Fan Assembly,
  • frequency speed control of the motor,
  • the oil temperature in the gearbox,
  • the oil pressure in the gearbox,
  • oil contamination in the gearbox,
  • heating oil in the gearbox,
  • the temperature of bearings and windings of the motor,
  • anti-condensation heated of the motor,
  • the coolant flow,
  • the liquid level in a collecting tank,
  • electricity consumption,
  • the fluid pressure in the pressure line,
  • frequency regulation speed of pumping equipment.

 

During the winter start-up is carried out by preheating the oil in the crankcase of the gearbox, with stopping of the electric motor anti-condensation heating is switched on.
 
In order to avoid overcooling of the coolant circuit (freezing system) is provided for reversing the rotation of the blades of the fan impeller.
 
For emergency shutdown of the electric motor provides local push button stations.
Optionally with the help of actuators it is possible automatic control of isolation valves and shutters of the tower.
 
If necessary, the local process control system can produce the pump station management, including frequency regulation, control of dry start-up pressure, overheating of the bearing assemblies of the pumps.
 

Available integration of local APCS in the complex treatment system of the enterprise protocols of Ethernet or RS-485/422/232.2. 



Block transformer substation for cooling towers SK-400, SK-1200
 

Block transformer substation combines the function of APCS and transformer cell (6000 V – 380 V) in single isolated block-module.
Driving equipment of a significant part of cooling towers old projects SK-400, SK-1200 operates at a voltage of 6000 V. the Problem of automation / replace worn high-voltage drive technology more effectively solved in low-voltage components. The savings from switching to voltage 380 V, up to 50%.
 
Process control is fully automated. Signals from sensors installed on process equipment cooling towers, shall be processed in the controller. The control algorithm does not require the presence of staff.
 
Block module designed for temperature range: from -60 ° C to +50 ° C.

БКТП. Внешний корпус   БКТП. Внутренняя часть   БКТП. Внутренняя часть   БКТП. Панель управления

Company AKVANN carries out a full complex of works on reconstruction of cooling towers of the type SK-400 or SK-1200 turnkey.
 

 Main Desing Completed Projects Contacts

+7 (831) 283-21-14

+7 (831) 224-01-74

info@akvann.ru

Calculations Solidworks Components of cooling towers

  

            

Cooling tower Engineering
Cooling towers SK-400, SK-1200 Draft shaft couplings
Compact cooling towers Download