Boiler Thermal Calculation - DBE, Drawings

General information on DE 1 boilers... 25

DE gas-oil boilers of the Biysk boiler plant and CKTI are designed to produce saturated or slightly superheated steam with an absolute pressure of 14 kgf/cm2 or 24 kgf/cm2, steam capacity of 1; 4; 6,5; 10; 16 and 25 t/h and combustion of gaseous and liquid fuel.

All DE gas-oil boilers have a supporting inclined frame that rests on the foundation. Mass of boiler and water elements, banding frame, natrubbing and skin are transferred to the frame. Front bottom of lower drum has fixed support, and other supports are sliding. Support (indicator) is installed on rear bottom of lower drum to control thermal expansion of boiler elements during operation and decay. Heat generators consist of upper and lower drums of equal length, which are connected to each other by corridor-arranged vertical bent pipes and form respectively the first and second gas ducts of convective heating surface. The longitudinal pitch of the boiling tubes along the drum is 90 mm and the transverse pitch is 110 mm. Steam capacity boilers 4; 6,5; 10 t/h in convective bundles have longitudinal metal partitions along the entire height of the gas duct with a window (from the front of the boiler) in front, which provides turning of flue gases in the bundle by 180 ° and gas outlet to the economizer through the rear wall of the boiler. Boilers with a steam capacity of 16 and 25 t/h do not have such partitions, and gases go along the entire section of the gas duct to the front of the boiler, exit the boiler, and then through a gas duct located above the furnace chamber, are sent to a water economizer located at the tail of the boiler.

For all sizes of gas-oil boilers DE, the diameters of the upper and lower drums are 1000 mm, the distance between the drums along the axes is 2750 mm. The width of the furnace chamber of all boilers along the axes of the screen pipes is 1790 mm, the average height of the furnace chamber is 2400 mm. Boilers drums are made of steel 16 GS and wall thickness 13 and 22 mm, respectively, for overpressure 13 and 23 kgf/cm2.

All tubes of the radiation and convective heating surface are flared in drums and have an outer diameter of 51 × 2.5 mm, which achieves better natural circulation in the boiler circuits. In the lower drum there are perforated pipes for periodic blowing and steam heating of water from neighboring boilers during melting, as well as nozzles for water lowering. The furnace chamber is located on the side (to the right) of the convective bundle and is separated from it on the left by a getter partition made of pipes installed with a pitch of 55 mm and welded to each other by metal strips. Ends of pipes of gas-tight screen are cased up to 38 mm, brought into two rows and sealed with comb adjoining pipes and drum. At the rear of the getter screen, at a distance of 700 mm from the rear wall of the boiler, there is a window for the flue gases to exit from the furnace into the convective bundle. The hearth, right side furnace screen and ceiling of the furnace are formed by long curved pipes installed with a pitch of 55 mm. The ends of these pipes are divided into two rows and connected directly to the upper and lower drums on the roller. Under (the lower part of the furnace) in the furnace is lined with a layer of refractory brick, chamotte brick is also laid on the side part of the lower drum in the furnace and is attached on studs on the side part of the upper drum in the furnace between the getter and ceiling screens. Vertical pipes of the rear furnace screen do not have casing ends and are welded to the lower and upper inclined headers with a diameter of 159 × 6 mm. Upper collector of rear furnace screen is welded to upper drum with downward inclination, and lower collector is welded to lower drum with upward inclination. In addition, the upper and lower headers are united by an unheated pipe with a diameter of 76 × 3.5 mm, which is walled up in chamotte brick. Water flows from the upper header to the lower one through the recirculation pipe when it is separated from the steam-water mixture. To protect the headers of the rear furnace screen from thermal radiation, they are equipped with two curved pipes, which are rolled into the lower and upper drums .

The front screen of the boiler furnace is formed by four curved pipes, flared into the upper and lower drums, which allows placing burner embrasures and blades on the front wall. Laz is combined with blasting valve. (In the first series of boilers with a capacity of 4... 10 t/h, the front screen had vertical pipes welded to the headers, similar to the design of the rear furnace screen). Boilers with a capacity of 4... 10 t/h have two modernized HMG burners or one GM each, and boilers with a capacity of 16 and 25 t/h have HM10 and GMP16 burners. In addition, boilers with a capacity of 4... 10 t/h in the furnace in front of the rear furnace screen have two rows of pipes of six pieces (twelve pipes in total), which are flared into the upper and lower drums and are guide screens for swirling and moving flue gases from the furnace to the boiling bundle of pipes.

DE boilers with a capacity of 4... 10 t/h are made with single-stage evaporation, and in boilers with a productivity of 16 and 25 t/h, two-stage evaporation with an intra-drum salt compartment is used.

The 16 and 25 tph DE boilers in the drums at a distance of 1.5 m from the rear wall have partitions that form a clean, located in the front of the boiler, and a salt compartment. In the upper drum the partition is installed to the middle of the steam space, and in the lower one there is a solid partition separating the second stage of evaporation from the first one. Downhole system of the first stage of evaporation consists of the last rows of pipes of convective bundle along the gas flow. First rows of convective bundle tubes are separated into second stage of evaporation along flow of flue gases. The lower circuit system of the salt compartment consists of three non-heated pipes with a diameter of 159 × 4.5 mm, through which water from the upper drum drops into the lower. Stepped evaporation compartments communicate with each other by steam through window above transverse partition, and by water through nozzle located in lower part of partition of upper drum water volume. This nozzle serves as a purge from the clean compartment to the salt compartment. As separation devices of the first stage of evaporation, shields and visors installed in the upper drum are used, directing the steam-water mixture from the screen pipes to the water level. To equalize steam speeds along the entire length of the drum, all boilers (of all capacities) are equipped with an upper hole steam receiving ceiling. A horizontal louver separator is installed in all boilers, except for boilers up to 4 t/h, in front of the steam receiving ceiling. Separation devices of the second stage of evaporation are longitudinal shields directing movement of steam-water mixture into end face of drum to transverse partition separating compartments.

On boilers with a steam capacity of 4... 10 t/h, periodic blowdown is combined with a continuous blowdown pipe. On boilers 16 and 25 t/h, periodic blowdown is carried out from clean and salt compartments, and continuous blowdown is carried out from the salt compartment of the upper drum. The quality of boiler (blowdown) water is normalized by the total salt content (dry residue) without taking into account absolute alkalinity.

Superheater is installed to produce superheated steam. On boilers 4... 10 t/h, the superheater is made of coil pipes with a diameter of 32 × 3 mm, and on boilers 16 and 25 t/h - two-row pipes of 51 × 2.5 mm. Standard cast iron water economizers EP 2 are used as heating tail surfaces. The trimming of the side walls, with a total thickness of 100 mm, is natrubnaya and consists of chamotconcrete (25 mm) along the grid and insulating (asbestovermiculite) plates. The coating of the front and rear walls, with a total thickness of 100 mm, consists of chamotte concrete (65 mm) and insulating plates; for boilers with a capacity of 16 and 25 t/h, the thickness of heat insulation plates 256... 300 mm. The outside of the boiler is covered with metal sheathing to reduce the suction of air into the gas duct. The boilers are equipped with stationary blowers located on the left side of the convective bundle. The blowing pipe, in order to increase the reliability of operation, is made of heat-resistant steel. The blowing pipe is manually rotated by pulley and chain. Dry saturated or superheated steam with a pressure of not less than 0.7 MPa is used to blow the boiler pipes. The boilers are equipped with an individual blast fan and smoke pump.

Each DE boiler is equipped according to the boiler rules:

two spring safety valves, of which one is a control valve; on boilers without superheater, both valves are installed on the upper drum (and either can be selected as a control); on boilers with superheater, the control valve is a valve on the outlet header of the superheater;

two water indication devices;

required number of thermometers, pressure gauges, shut-off, drain and drain valves;

Control and safety devices

Main circuits of natural circulation of DE2514 GM boilers.

Feed water is supplied to the water volume of the clean compartment of the upper drum, where it is mixed with boiler water. The boiler has six natural circulation circuits: three in the clean and three in the salt compartment:

Clean compartment, first evaporation stage.

1st circuit (via reboiling pipes of clean compartment). Boiler water from the upper drum is lowered into the lower drum, along the boiling pipes located closer to the front of the boiler in the area of ​ ​ lower temperatures of flue gases, and along the boiling pipes located closer to the partition in the area of ​ ​ higher temperatures, water and steam-water mixture (PVA) rise into the upper drum.

2nd circuit (along the front screen) - boiler water from the lower drum rises up through four pipes and enters the upper drum in the form of a PVA.

3rd circuit (along the bottom, right side and ceiling screen located before the partition) - boiler water from the lower drum fills the pipes and enters the upper drum in the form of PVA.

Salt compartment, second evaporation stage.

The 4th circuit (through the boiling pipes of the salt compartment) - boiler water from the upper drum through three downhole unheated pipes goes to the lower drum, and through the boiling pipes located behind the partition, the formed PVC rises to the upper drum.

The 5th circuit (along the rear furnace screen) - boiler water from the lower drum enters the lower header of the screen, is distributed along the screen pipes, and the PVC formed in them rises to the upper header. Due to flow stratification in the upper manifold, the steam goes to the upper drum, and water separated from the PVC is lowered to the lower manifold through a lowered unheated pipe.

6th circuit (along the bottom, right side and ceiling screen located behind the partition) - boiler water from the lower drum fills the pipes and enters the upper drum in the form of PVA. Wet-saturated steam in the upper drum passes steam separation devices, and the obtained dry saturated steam is taken out of the clean compartment and goes through the steam line to the consumer.

ДЕ-25-14-225.dwg

Котел ДЕ 16-14.dwg