Reconstruction of Ekibastuz GRES-1

Working relieves a human from three main evils: boredom, sin, and need.

Voltaire

Supply of drives for tangential hammer mills under the project of reconstruction of Ekibastuz GRES-1.

Ekibastuz GRES-1 is the largest heat station in the town of Ekibastuz in Pavlodar region of Kazakhstan. LLP “Ekibastuz GRES-1 named after Bulat Nurzhanov” is a heat power station of condensation type with total capacity 4000 MW which produces and distributes electric power .Power station Ekibastuz GRES-1 is owned on parity basis by National Welfare Fund “Samruk-Kazyna” and the Group Kasakhmys. The main fuel for the station is coal from Ekibastuz deposites. The main part of power produced by the station is distributed at the energy market of Kazakhstan.

The construction of the first sites of Ekibastuz GRES-1 started in January 1974(drawing 1). The power station is situated on the northern bank of Lake Zhengeldy, 16 km to the north from the town of Ekibastuz in Pavlodar region. The station was being constructed under the project of the USSR- formation of Ekibastuz Fuel and Energy Complex. The location of the station was determined by its proximity to coal mining deposits of Kazakhstan (there is the largest coal mining deposit “Bogatyr” in the world at the distance of 25 km to the east).

Water-supply source is water reservoir made in the basin of Lake Zhengeldy that is watered from the canal “Irtysh-Karaganda named after Satpaev”.

Drawing 1. Ekibastuz GRES-1- in 1980-s and nowadays.

In 2010 KOTES completed the project of reconstruction of energy unit 8 at Ekibastuz GRES-1 and designed the project of construction of energy unit 525 MW at Ekibastuz GRES-2. The project underwent the state examination.

In 2011 KOTES started design working examination on reconstruction of energy unit №2 500 MW at Ekibastuz GRES-1.Now the working schedule on examination of existing equipment and structural engineering as well as design specifications and estimates is designed and agreed.

The engineers faces the task of reconstruction and recovery of energy unit №2 at GRES-1 taking into account the world experience of implementation of technical solutions and leading manufacturers of equipment. The start-up of recovered energy unit is scheduled for 2014.

Modern technical solutions and equipment that now will be suggested for reconstruction of energy unit №2 and construction of energy unit №3 are expected to be unified and can be used at further recovery and construction of generating power of energy complex. Usage of 3D-model of energy units 500MW made with the program of solid design PDMS AVEVA (Drawing 3).

                                                                                          Drawing 2. 3D-model of energy units 500 MW at Ekibastuz GRES-1.

Steam boilerПп-1650 made by JSC “Podolsk Machine-Building Plant”, steam turbine K-450 made by JSC “Turboatom” in Kharkov, and generator TBB-500 made by JSC “Power machines” will be set at energy unit. The main fuel of the station will be Ekibastuz coal.

Tangential hammer mills MMT 2600/2550/600К(made by JSC “Tyazhmash”, Syzran) will be implemented at the complex of pulverizing. The mills are used to pulverize and at the same time to dry coal and brown coal in the pulverizing systems at power stations. The equipment can be operated both at rarefaction and at pressure. Differential characteristic of the mill is intensive forced ventilation combined with increased rim speed of rotor that gives high quality of pulverizing and good dry. Mill material and drying agent are given to the mill tangentionally. Pulverizing is made with repeated blows of material with hammers and over the hull armour, and also with galling of material moving in nip between hull armour and rotating housing of the mill.

                                                                                                 Drawing 3. 3D-model of hammer mill.

Pulverized coal is taken away from pulverizing zone with dry- ventilation agent to separator where big fractions are separated and given back to the mill to be pulverized again. Ready-made coal dust is taken to boiler burnings via coal pipes. Efficiency of modern hammer mills reaches 70 t/h on brown coal and 50-60 t/h on coal. Modern hammer mill is one of the most economical milling equipment used for coal pulverization.

Selection of drives for mills is a difficult task. MillММТ 2600/2550/600Кis a heavy mechanism for start-up( drawing 4), dynamic torque and big rotating mass. It can be the source of vibration that will be transferred to electric motor, for this reason the former must have sufficient safety factor, ability to bear frequent, heavy starts and it must be adopted for crushing and mill equipment. On the other hand, any drive mechanism can be described with the formula and curves language, and in this case selection of electric motor will be just an engineering task.

Drawing 4. Mill MMT 2600/2550/600К resistance torque to motor speed at start curve.

As a result of analysis of variants of drives specialists of our company selected electric motors

АДО-1250/600У3 (drawing 5) made by NPO “Elsib” JSC (Novosibirsk) as besides exact correspondence to the above mentioned characteristics they also have some significant advantages over their competitors. The electric motors are innovative machines used for drives of hammer mills, exhausters, draft machines and other auxiliary equipment. They showed high operational parameters including high reliability at many generating companies in Russia and CIS-countries. This type of electric motors started a production run of this machines for drive of mills and draft machines at energy units of power stations (drawing 6). Existing unification of these electric motors with drives of mills of other energy units and drives of grinders type СМД97А can give more freedom to repairing staff at planning and repairing operations.

Drawing 5. Electric motor type АДО – rotor-stator winding up at assembly work.

Besides, electric motors have the following advantages unobvious at first sight:

-higher efficiency;

-less weight at equal power factor;

-high breakdown and starting torque;

-higher heat capacity of rotor winding;

- less heating-up of rotor winding at start;

-higher reliability proved by tests of full-scale specimens and long-time experience of operation of electric motors.

Drawing 6. Outline drawing of electric motor АДО-1250/600 У3.

NPO “Elsib” JSC uses best practices of world leading manufacturers, launching electric motors АДО-1250/600 У3 with winding insulation class “ monolith 4”. The first running repair is done in 6 months after start-up with its partly disassembling without dismantling of rotor from stator. Period of further running repairs is fixed in accordance with serviceability status, but not less than one time a year.

Table 1. Main technical characteristics of electric motorАДО-1250/600У3

Electric motor was additionally equipped with vibration transducers ВК-310НС. This device is piezoelectric converter with in-built interfacial preamplifier and it is used to measure vibration level of assemblies of different industrial equipment. Vibration transducer is connected via two-wired scheme, at the output unified DC-signal 4…20 mA proportional to total amplitude of vibration displacement of electric motor. Converters are protected from penetration of solid bodies and water, with 10-year of lifetime.

To find out the correspondence to all technical conditions and design documentation electric motors АДО-1250/600 У3 were tested before the dispatch.

Based on the results of the tests with participation of service staff from JSC “EnergoFront” and specialists from JSC “Tyazhmash” all 8 electric motors approved full correspondence with GOST-R including low vibration value at bearing assemblies.

Now electric motors are delivered at the site of commissioning and operation. Specialists from JSC “EnergoFront” will make all complex of services on arranging and control over pre-commissioning activities.