Steam boilers DKVR-2,5; 4; 6,5; 10 with oil-gas burner – double-drummed, vertical water tube boilers designed for saturated or preheated steam producing for heating, ventilation and hot water supply.
Advantages
- Reliable hydraulic and aerodynamic operation scheme provides high efficiency up to 91%
- Low operation and maintenance cost
- DKVR boiler has built-up structure which allows the installation in the boiler house without wall destruction, and quick connection to the existing systems.
- Boiler reconstruction for another fuel type is possible.
- Wide range of capacity regulation (40 to 150% of nominal) enables to use the boiler with maximum efficiency and decrease the costs of heat and energy supply.
- Boiler transfer to the water heating mode is available.
- Due to the boiler design different instrumentation sets can be used on request, including automated burners
DKVR boilers technical data and complete set
| Boiler unit type | DKVR-2,5-13GM | DKVR-4,0-13GM | DKVR-6,5-13GM | DKVR-10-13GM | DKVR-20-13GM |
| Nominal steam efficiency, t/h | 2,5 | 4 | 6,5 | 10 | 20 |
| Steam pressure, MPa (kg/cm2) | 1,3(13) | 1,3(13) | 1,3(13) | 1,3(13) | 1,3(13) |
| Steam temperature, °Ñ | 194 | 194 | 194 | 194 | 194 |
| Boiler heating surface, m2 radiating/ convectional/ total | 17,7/73,6/91,3 | 21,4/116,9/138,3 | 27,9/197,4/225,8 | 47,9/229,1/227,0 | 51,3/357,4/408,7 |
| Boiler volume, m3, steam / water | 1,57/4,00 | 2,05/5,55 | 2,55/7,80 | 2,63/9,11 | 1,80/10,5 |
| Fuel type | gas, fuel oil | gas, fuel oil | gas, fuel oil | gas, fuel oil | gas, fuel oil |
| Fuel flow, m3/h (kg/h): gas (fuel oil)* | 194(180) | 310(288) | 505 (468) | 776 (720) | 1550(1440) |
| Design efficiency, %: gas/ fuel oil | 90/88,8 | 90/88,8 | 91/89,5 | 91/89,5 | 92/90 |
| Weight, kg | 7068 | 7800 | 12200 | 16 000 | 43 700 |
| Boiler overall dimensions, m (length x width x height) | 4,1x3,2x4,3 | 5,4x3,4x4,4 | 6,5x3,8x4,4 | 6,8x3,8x6,3 | 9,7x3,2x7,6 |
| Economizer: cast iron | EB2-94 | EB2-142 | EB2-236 | EB1-330 | EB1-646È |
| steel | IBVES1-2 | IBVESÈ-2 | IBVESØ-2 | IBVESIV-1 | - |
| Fan | VDN-8(1500) | VDN-10(1000) | VDN-9(1500) | VDN-11,2 (1000) | VDN-12,5 (1000) |
| Induced fan | DN-9(1000) | DN-9(1000) | DN-9(1000) | DN-10(1500) | DN-13(1500) |
| Burner: oil-gas | GMG-1,5Ì | GMG-2Ì (2 øò.) | GMG-4Ì (2 øò.) | GMG-4Ì (2 øò.) | GMG-5Ì (3 øò.) |
| gas | MDGG-180 | MDGG-250 | MDGG-400 (1 øò.) MDGG-250 (2 ea.) | MDGG-400 (2 ea.) | MDGG-500 (3 øò.) MDGG-800 (2 ea.) |
| Delivery (package, in bulk, etc) | package, in bulk | package, in bulk | package, in bulk | in bulk | in bulk |
* For gas Qdesign=8525 kkal/kg, for fuel oil Qdesign=9170 kkal/kg
Note: DKVR-2,5; 4; 6,5; 10 boilers are complete with GMG two-zone swirl oil-gas burners. To save fuel and improve steam quality boilers are complete with MDGG micro-diffusion burners with “Alfa XXI” automated control.
Structural description and operational principles
Boiler has the upper long and the lower short drums, arranged alongside the boiler axis. Boilers have screened furnace and advanced boiling bundle made of bent tubes. Furnace of boilers DKVR-2,5; DKVR-4; DKVR-6,5 divided into two parts with fireclay barrier: furnace itself and afterburner. The DKVR-10 boilers have afterburner separated from furnace with back screen tubes. There is also fireclay barrier between the first and the second rows of tubes of boilers bundle, which separates bundle from afterburner.
There is a cast iron barrier inside the boiler bundle, dividing it for the first and the second flue ducts and providing horizontal turn of gases in bundles at tubes cross-washing.
Gas inlet between furnace and afterburner as well as boiler gas outlet are dissymmetric. At presence of super-heater, some part of boiling tubes is not mounted. Super-heaters arranged on the first flue duct behind the second and third rows of boiling tubes.
Boilers have two drums – upper (long), lower (short) and piping.
There are oval holes (325x400mm) on bottoms to inspect drums, to mount devices inside, and to clean piping.
Drums (dia. 1000 mm; pressure 1,4 MPa) are made of steel (grade 16ÃÑ or 09Ã2Ñ) with 13 mm wall thickness. Screens and boiling bundles are made of steel seamless pipes.
All boilers are equipped with intra-drum steam separation device for vapor generation. Boilers series DKVr-2,5, DKVr -4 and DKVr -6,5 have welded support frame made of rolled iron.
Boiler series DKVr -10 has no support frame. Fixed and rigidly fastened point of boiler is used as a front support of lower drum. The other supports of lower drum and chambers of side screens are movable. Chambers of front and back screens are fixing to blower frame by cantilever. Chambers of side screens fix to support frame.
There are front hatches in the lower screen chambers of boilers for sludge removal, and fittings (dia. 32x3mm) for periodical purge of boilers. Super-heaters are arranged in the first flue duct, their profile is uniform for boilers of the same pressure and defined only by the number of parallel coils for boilers of different output.
Super-heaters provide generation of superheated steam without using of attemperators. Chamber for superheated steam is fastened to the upper drum. One of the chamber supports is fixed and the other is movable.
DKVR boiler circulation system
Feed water comes to the upper drum through two feed lines, and then to the lower drum. Screens are fed via non-heated tubes from upper and lower drums. Front screen of boilers is fed with water from downtake tubes of upper drum; back screen is fed through downtake tubes of lower drum. Water-steam mixture coming from screens and lifting pipes bundle is forwarded to the upper drum.All boilers are equipped with steam separating device inside the drum for steam generation.
DKVR-2,5, DKVR-4 and DKVR-6,5 boilers which can be supplied in one transportable package and knocked-down, have a welded support frame made of rolled steel.
DKVR-10 boilers have no support frame. Immovable, rigidly fixed boiler point of the is the lower drum front support. Other lower drum and side screen chambers supports are sliding. Front and back screen chambers are fixed brackets to the sootblower frame. Side screen chambers are fixed to the support frame.
Boiler equipped with instrumentation and all necessary fittings, as follows:
- safety valves
- pressure gauges and T-valves
- frames of level gages with glasses and locking devices
- shutoff valves and back-pressure valves for boiler feeding
- shutoff valves for purge of drums, screen chambers, feed-water regulator and super-heater
- shutoff valves for saturated steam withdrawal (for boilers w/o super-heaters)
- shutoff valves for superheated steam withdrawal (for boilers w/ super-heaters)
- shutoff valves on the line of lower boiler purge and heating at boilers kindling (for DKVr-10 boilers)
- valves for lower drum water discharge
- shutoff valves on the line of chemicals inlet
- valves for steam sampling
DKVR boilers drums
Boiler pipeline connection with the drum of the DKVR boiler is not welded, but forge-rolled. This increases the boiler maintainability and reliability. Automated welding complex usage gives an opportunity to produce DKVR drums of the high quality. IG “Generation” supplies DKVR repair packages and DKVR drums
.jpg)
DKVR-4, DKVR-6,5, DKVR-10 boilers upper drum DKVR-4, DKVR-6,5, DKVR-10 boilers lower drum
DKVR boilers drums overall dimensions
.jpg)
| Overall dimensions, mm | DKVR-4 | DKVR-6,5 | DKVR-10 | DKVR-20 |
| L, mm | 5418 | 6680 | 6990 | 5300 |
| L1, mm | 2414 | 3266 | 3587 | 5300 |
Operation data
DKVR boiler reliable operation at low pressure as against to nominal is proven by numerous tests and long-term experience of a large number of boilers. Minimal allowable (absolute) pressure for DKVR-2,5; 4; 6,5; 10 boilers is 0,7 MPa (7 kg/cm2)
Boiler unit efficiency does not decrease with operation pressure decrease. It is verified by comparative heat calculations
Boiler details are designed for operation pressure of 1,4 MPa. Safety valves on the boiler provide safety operation.
Boiler complement with economizer doesn’t change with the pressure decrease up to 0.7 MPa. In feeding economizers water underheating temperature to steam saturation temperature in the boiler is 20ºC, which is in compliance with Gosgortechnadzor requirements.
MDGG series microdiffusion gas burners
Gas block burner is complete with modern gas fittings providing safety and efficient operation. Boiler design is based on the best qualities of kinetic and diffusion fuel consumption, providing short flare high parameters and gas saving up to 30% comparing with usual burners.
- Low excess air ratio
- Ecologically harmless combustion process
- Low aerodynamic resistance
- Stable combustion process
- Short flare
- High degree of temperature field uniformity in furnace
- High control factor
