Network pumping units for the reconstructing pumping station No. 4 of «BashRTS» in Ufa

Limited Liability Company «Bashkir heat distribution system» (LLC «BashRTS»), established in December 2005, provides heat to eight cities in the Republic of Bashkortostan, including Ufa, Blagoveshchensk, Sterlitamak and others. It is a subsidiary of LLC «Bashkir Generation Company». LLC «BashRTS» serves 26 boiler houses, 304 central heating stations (TSC), 21 pumping stations. The total length of highways and quarterly networks in the two-pipe calculation for 2017 is 1480 p.km. The installed electric and thermal capacity of LLC «BashRTS» is 24 MW and 3587.45 Gcal/h, respectively.

Ufa is a rapidly developing city with active housing development. To meet the growing demand for heat, the existing heating networks are being modernized and new ones are being constructed in accordance with the approved Heat supply scheme for the urban district of Ufa for the period until 2028.

The existing pumping station No. 4 is located on the ground floor of a commercial building on October prospekt and is designed to maintain the hydraulic regime of consumers from TM-25 heating system during the heating period. NS-4 is equipped with three morally and physically obsolete pumping units of SE 1250-140-8 series. The efficiency of pumping units does not exceed 80%, and the operating parameters do not meet the new requirements of the Ufa heat supply scheme.

In accordance with the new scheme, NS-4 should ensure:

expense

• G=2000-2500 m3/h;

temperature schedule coolant

• in winter 150-70° C, with a cut of the direct mains water temperature at 130°C;

• in summer 70-30° C;

working pressure

• P₁ = 4,0 ÷ 6,0 kgf/cm2 at pump suction;

• Р^1' = 10.5 ÷ 11.5 kgf/cm2 - after RC-1;

• P₂ = 6.0 - 7.0 kgf/cm2 – return pipe.

Thus, pumping units should provide head at rated operating mode up to 80 m.

The pumping station is currently equipped with a frequency converter installed in the block-box next to the building of the pumping station, but after the reconstruction, it was agreed to abandon it.

Reconstructed pumping station should be located in a new building made of metal structures, which will be located to the East of the existing building. The pumping station must be completely autonomous with the information and tele-monitoring output on the central control panel. For this purpose the equipment of station, including pumping units, should have high level of automation and expanded CPS, including vibration and temperature control of pumping unit bearings. The autonomy of the station also requires high level of redundancy of the main equipment and its reliability.

The specialists of the company «EnergoFront» had the <b><span style="color: #ee730c;">task</span></b> to find a technical solution for pumping units, which would ensure high performance of the pumping station, meet all the requirements for its automation, regulation and reliability, as well as give a tangible economic effect of reconstruction at the unit cost of electricity per ton of pumped water.

Specialists of our company together with JSC «HMS Livgidromash» developed a technical solution based on four pumping units Delium D300-580V-S/N-tt-UHL3.1, two of which are equipped with hydrodynamic couplings of alternating filling Transfluid 27KPTB. All pumping units are equipped with electric motors (N = 500 kW, U = 6000V, 50 Hz, n =1500 rpm). Two pumping units are in operation, one of which with a hydraulic coupling, two in reserve. This arrangement provides double reservation, as well as a high degree of maneuverability of the pump station.

Delium pumping units manufactured by JSC «HMS Livgidromash» are a new line of unified two-way inlet pumping units to replace outdated series of pumps of type D and CE. The pumps are designed to meet modern requirements for power consumption, reliability and long term operation and have the following design characteristics:

• optimized flow section hydraulics with maximum efficiency;

• body made of high-strength ductile iron or steel with internal pressure up to 25 kgf/cm2;

• high-strength chrome steel shaft is completely insulated from the pumped medium and atmosphere by protective sleeves;

• depending on the pumped medium and the customer's wishes, the pumps can be equipped with both gland and single or double mechanical seals;

• reduced dimensions of the pump and the unit on its base compared to the pumps of the CE type by 20%, compared to the pumps of the D type by 10%. The mass of the pump is reduced by 25-40% compared to pumps of the SE type and 5-10% compared to pumps of the D type of similar capacity;

• suction and discharge nozzles, implemented «in a line»;

• two-winding spiral tap, reducing radial load on the rotor and bearings, which significantly increases their service life;

• standard or reinforced grease-lubricated bearings that do not require cooling systems, even at temperatures of 150°C of the pumped medium, the bearings service life is increased and ranges from 16,000 to 100,000 hours;

• a wide range of models (more than 45 dimension types) and the use of at least two interchangeable impellers for one dimension type of the body allows to choose the pump for any task within the operating range  from 80 to 10 000 m³/h and pressure head from 5 to 200 m.

These features make Delium pumps unique in comparison to other pumping units of domestic production and not inferior to modern analogues of foreign production.

The feature of the proposed technical solution is the use of a steel version of the pumping units with a body made of St20L steel and a stainless steel impeller, which provides the required reliability of the pump at high pressure in the housing and increased loads on the nozzles, due to the high temperatures of the pumped medium.

To ensure the required safety of maintenance of the pumping units when transferring medium with a temperature of 150°C, the pumps are equipped with double end seals, excluding the outlet of the pumped medium outside the housing. To compensate for thermal expansion and simplify the operation process, the pumping units are equipped with an elastic plate coupling that does not have wearing parts and does not require maintenance.

The pumping units must provide a flow rate at a nominal mode of 1500 m³/h and a head of 80 m, the hydraulic KPI should not be lower than 84,4%. Due to the high efficiency, power consumption at rated load will be only 404 kW, which will provide 20% of the reserve power of the motor. The unit costs of electricity per tonne of pumped medium in the nominal mode will be not more than 0.26 kW*h/t.

Operating characteristics of the pumping unit Delium D300-580V-S/N-tt-UHL3.1

The proposed pumping units have a wide operating range from 850 to 2200 m³/h with a flat KPI characteristic, which can significantly increase the maneuverability of the pumping station. 

Hydrodynamic coupling 27KPTB made by Transfluid (Italy) with adjustable filling is designed as a variable-speed drive or as a triggering mechanism. KPTB has an external feed pump and a remote-controlled electric valve with ON-OFF positions. When the valve is in ON position, the oil supply of the hydraulic coupling occurs, when we switch to OFF, there is a rapid drainage of the oil through the peripheral holes. Reinforced lubrication of bearings is provided in both cases. The oil pump can operate through the valve of oil flow or from motor with VFD, which allows KPTB coupling to be a variable drive. КРТВ couplings are suitable for capacities up to 1700 kW, as triggering mechanisms and up to 600 kW as variable-speed drive. The output shaft is connected to the pump by means of an elastic plate coupling.

The main components of the hydraulic coupling are: feeding oil pump, oil filter with pressure and temperature sensors, electric valve, oil temperature switch, oil level indicator, stamped box with connector, air-to-oil heat exchanger, quick discharge valve.

The hydrodynamic coupling with adjustable filling 27KPTB has the following advantages:

• idle engine start-up;

• smooth start, which is possible at the rated current of the electric motor at full control of the start process;

• shock and overload protection;

• vibration damping;

• remote control by means of electro valve;

• load positioning;

• feed pump, oil filter and electro-valve are installed externally for easy maintenance;

• extended service life due to the lack of wearing parts;

• accuracy of preset speed adjustment;

As a result of joint work of specialists of companies «EnergoFront», «Livgidromash» and «BashRTS», developed decision was finally agreed and included in the working draft of reconstruction of the pumping station No.4.

Project achievements

Our company together with our production partners facing the task to manufacture, test and deliver pumping units to the customer in the set term, till September of this year. The tight delivery schedule is induced by «BashRTS» plans to put the pumping station into operation before the start of the new heating season.

Works on supervision of installation and commissioning will be carried out by specialists of our company.