Reconstruction of energy unit №5 at Aksu TPP

Aksu TPP ( former  Ermakovskaya state district power station) was formed in 1968. Then in 1960-70s the station was considered to be the biggest power station not only in Kazakhstan but in all Middle Asia. In 1996 the station became a part of JSC “Eurasian Energy Corporation”.

Today there are eight energy units with total capacity   2400MW at the TPP. The station works on brown coal from the mine “Vostochny” ( Ekibastuz).

Aksu TPP is the head company of JSC “Eurasian Energy Corporation” (concern ENRC) - the biggest supplier of energy at the market of  Kazakhstan. The station makes 16% of all power energy in the country. Today this energy is used by the largest companies of the country- JSC “Sokolovsko-Sarbayskoe mining and processing combine”, JSC “Transnational Company “Kazchrom”, JSC “Aluminum of Kazakhstan”, and etc.

All energy units at Aksu TPP were put into operation at the end of 1960s – the beginning of 1970s. By the time when TPP  became a part of JSC “Eurasian Energy Corporation”, its equipment had already been worn out.

It was impossible to deal without proper technical reinforcement, so the program of gradual reconstruction of energy units aimed to increase  capacity reserve, reliability and long life of equipment, increasing its production characteristics and ecological data was made. The first step in the global reinforcement was modernization of energy unit №4.

The turbine was completely replaced, control and supervision system was modernized,  system of turbine regulation and system of unit protection  were set.

The new equipment has higher technical and economical characteristic that decreased specific charge of fuel, increase economical operation of energy unit on the whole. The total capacity of the unit has been grown, by 10MW. In March 2005 one more energy unit at Aksu TPP- №3 was put out of operation for the same reconstruction. The equipment set at the third unit is even more modern. The turbine was replaced for more powerful one that increased capacity  by 25 MW. Today the second and the sixth units have also been reconstructed.

In 2012 the general contractor GK “SibEnergoGroup” started to prepare design of the reconstruction of energy unit №5.

According to the schedule there will be full replacement of main and auxiliary equipment of the unit. Instead of worn out turbine there will be turbo aggregate of the new generation K-325, designed by  JSC “Turboatom”, modernized boiler ПК-39-IIM by “ Podolsk machine works”,  roller mill MBC-195 produced by JSC “Tyazhmash”.

The result of work will be increasing of capacity by 25MW, decrease of discharges to the atmosphere and decrease of auxiliary expenses.

As a scheme of pulverizing the system of eight roll mills MBC-195 produced by JSC “Tyazhmash” (Syzran) will be used as at the previous units. They are used to break coal and brown coal to dust in pulverizing sections of power stations .Roll mill consists of flat rotary table where two cone-shaped rolls placed on stable axis roll over. The rolls are pressed to the table with springs.

Fuel is supplied to the table, and while it’s turning fuel goes under rolls and pressed under pressure made with spring tension. The rolls don’t just roll over but slide on the table that makes additional effect of breaking-galling.

Broken fuel is taken with primary air to separator where big fractions are separated and returned for additional breaking to mill. The ready coal dust is taken to burner of boiler. Productivity of roll mill MBC-195 reaches 40t/h.

Task: Selection and supply of electric motors for mill MBC-195 under the project of reconstruction of energy unit №5.

Electric motors for the drive of mills

Under strategic partnership between JSC “EnergoFront” and JSC “Tyazhmash” the mills MBC-195 were completed with electric motors.

Having analyzed modern market of manufacturers of electric motors and made technical work out  the most optimal technical solution  was offered- induction electric motor 2АДО1-400-6000-6У1М( 400kW,6P,50Hz, IP54) produced by NPO “Elsib” JSC( Novosibirsk).

Selection of drive of mills is a difficult task. On the other hand, any drive mechanism can be described with formula, curves and then selection of electric motor will be just an engineering task.

Drawing.2  Mill MBC-195 resistant torque to motor speed at start curve

As a result of analysis of drives specialists of our company chose electric motors type 2АДО1-400-6000-6У1М(Drawing 3) produced by NPO “Elsib” JSC (Novosibirsk).

Basing of the results of common technical meeting held with JSC “EnergoFront”, NPO “Elsib” JSC, and Aksu TPP to increase energy characteristics, efficiencyandcosφ of electric motor manufacturer of electric motor has modernized some assemblies. Thermal condition of bearing assembly was improved at the expense of decreasing of rotor weight and design of new casing of bearing assembly with increased cooling surface.

Selection was based on high operation characteristics and technical data. This type of electric motors showed high reliability at many sites of power generation in Russia and former CIS- countries (including at previous units at Aksu TPP).