Tender for this co-generation unit construction won company SIA “Energoremonts Riga”, which is our customer-partner for many years of cooperation. For this implementation UAB “Gandras Energoefektas” took part in supply of steam boiler which steam parameters are 40 bar, 440C, capacity 25 t/h (boiler manufacturer – company Wellons, USA) and also supplied such station components as: deaerator, water heatexchanger, condensate heatexchanger, expansion vessel (separator tank), desuperheater, safety valve, 3 way damper, vent silencer, shut off and control valves and other components.


deaeratorsFrom the beginning final customer specified high requirements to water quality after deaerator – it was required that dissolved oxygen q-ty will not exceed more than 0.007 mg/l. This task was achieved by using thermo-physical deaerator.
The thermo-physical deaeration process is by far the most applied technology in the Boiler Feedwater Degassing when a reduction of oxygen to only a few parts per billion is required. The degassing process is achieved in the deaerating tower where water is atomized on a set of special stainless steel packing that increases the contact surface between water and steam. Oxygen and carbon dioxide are stripped by the steam flow and vented through an orifice. Deaerated water is collected in the storage tank.
According to the design power and steam consumption deaerating tower can be performed in a vertical design.

Unit technical data:
Working pressure 0,44 bar g
Working temperature 110°С
Max. deaerated water flow 30 t/h
Residual oxygen content not more than 0,007 mg/l
Make up water flow 4 t/h
Make up water temperature 20°С
Condensate flow 24,56 t/h
Condensate temperature 90°С
Steam flow 1,539 t/h
Steam pressure 5 bar a.
Steam temperature 240°С
  EXPANSION VESSEL (steam separator)

Расширительный бакThe expansion vessel was designed based on final customer drawings and wishes. Gandras took in account constrained installation conditions.
Expansion vessel is designed to separate steam-water mixtures formed from boiler blowdown water, steam pipes drainage ant atc., for steam and water by reducing its pressure to the pressure in expansion vessel for further hot water and steam use.
Gandras energoefektas supplied expansion vessel complete with all necessary nozzles, brackets and pipes. Customer goal was to get such expansion vessel which will not create pressure more than 0.2 bar, in other case it will require to install safety valve on vessel housing.
Equipment is designed and manufactured in accordance with PED 97/23 (other standards on request).

Technical data:
Working medium steam / condensate
Volume 1600 l
Inlet temperature 450°С
Inlet pressure 40 bar
Outlet temperature 104°С
Outlet pressure 0,2 bar
Housing design pressure 5 bar
Housing design temperature 160°С
Outside diameter 824 mm
Tank height 2850 mm
Total height 3825 mm

redukcinis-ausinimo-irenginysScope of supply: pressure control valve, spray water control valve, expansion chamber complete with tapped bosses for pressure and temperature sensors, drain connection, and internal baffle plate. Spray water complete with 1 mt. flexible stainless steel hose with all necessary fittings to connect the water control valve to the spray nozzle inlet on the main pressure control valve. Control valves were supplied with electrical actuators.
Also we supplied all necessary valves for water supply line: shut off valves, filter.
It is necessary to fit safety valve after desuperheater for equipment protection. Safety valve set excess pressure free and prevents accidents caused by unreduced steam flow in case of steam control valve failure. Number of safety valve depends on unit performance and steam parameters.
In this case it was needed to install two safety valves, but because of constrained conditions and in order to save on second (full size) safety valve delivery Gandras energoefektas supplied double acting safety valve. Valve consists of main valve and relay valve. The relay valve is generally set between 0.14-0.344 bar above the main valve. If the pressure in a system exceeds set pressure 4 bar g main valve overcomes the main spring loading and opens with a clean action. If the pressure continues to rise and reaches 4.14 bar g the pressure at the relay valve overcomes its spring loading The discharge from the relay valve is directed by port to the underside of the main piston. This action will further compress the main spring thereby giving the main valve full lift discharge.
Control valve leakage class is IV. It is 0.01% leakage of full open valve capacity.

Unit technical data:
Max. steam flow 20 000 kg/h
Min. steam flow 4 000 kg/h
Steam inlet pressure 40 bаr g
Steam outlet pressure 4 bаr g
Steam inlet temperature 450°С
Steam outlet temperature 250°С
Leakage class IV
Technical data:
Duct dimensions (D) 1500х1200 mm
Medium suitable for fumes and air at high temperatures
Tightness 99,9% HT Glass Fibre
Min. ambient temperature -30°C
Max. working temperature 200°С
Max. working pressure 1 bar
Entirely materials carbon steel P385NH (ASTM A516 J170)
Shaft С45
Connection type flanged
Control Double acting pneumatic cylinder group with Single coil solenoid valve connector, voltage 24VDC Inductive sensors in open/close position.

ШумоглушительBoiler operation is related to possible steam discharge. Boiler steam discharges to the atmosphere are the most powerful source of noise impact to environment. Acoustic measurements show that at 1…15 m distance from steam boiler emissions sound levels exceed not only permissible, but maximums sound level too.
Our supplied silencer reduced noise level from 151 dB (A) to ≤ 70 dB (A)

Technical data:
Working medium Steam
Scope of supply rain/snow cap, brackets, collar sheet
Noise level ≤ 70 dB(A) in a distance of 30 m from the silencer body
Flow rate 107 t/h
Max. temperature +450°С
Body stainless steel 1.4301
Inlet pipes carbon steel 1.0345
Diffuser stainless steel 1.4301
Gate valves up to DN600 PN25 and other valves, including high pressure up to PN100 valves
Medium water, steam
Temperature up to 445°С
Control рhand lever/wheel or el. actuator
Connection welded, wafer or flanged
Different design – type control valve
Different design – type control valve

Ball, sector, globe, piston type control valves. Most difficult task which company Gandras Energoefektas solved is the supply of control valve, which allowed decrease pressure from 42 bara to 1 bara.

High pressure cut off valve
High pressure cut off valve

Company Gandras energoefektas supplied cut off Butterlfy type valve which nominal pressure is PN100 and group with pneumatic actuator which open operation time was < 0,5 sek. Leakage class of this valve is VI and max. temperature +500°С.