PURPOSE OF THE PRODUCT
DE boilers are double-drum, vertical-water-tube boilers designed to produce saturated or slightly superheated steam used for the technological needs of industrial enterprises, heating, ventilation and hot water supply systems.
The main technical characteristics of the DE-16-14GMO boiler are given in the table.
Price
RUB 4,800,000
Model specifications
| Boiler | DE-16-14GMO | Steam capacity, t/h | 16 |
|---|---|
| Operating pressure(excess) steam at the outlet, MPa (kg/cm?) | 1,3 (13) | Temperature of superheated steam at the outlet, ?С | 194 |
| Feed water temperature, ? C | 100 | Estimated efficiency (gas), % | 93 |
| Estimated efficiency (fuel oil), % | 90 | Estimated fuel consumption (gas), m?/h | 1141 |
| Estimated fuel consumption (fuel oil), m?/h | 1088 | Total heating surface of the boiler, m? | 193 |
| Superheater heating surface | - | Boiler water volume, m? | 13,3 |
| Steam volume of the boiler, m? | 2,3 | Water supply in water indicator glass at max. level, min | 3,9 |
| Total number of convective bundle tubes, pcs. | 532 | Dimensions of transportable unit, LxWxH, mm | 7180x3030x4032 |
| Layout dimensions, LxWxH, mm | 8655x5240x6072 | Boiler length (with stairs and platforms), mm | 6478 |
| Boiler width, mm | 4300 | Boiler height, mm | 5050 |
| Weight of transportable boiler block, kg | 19130 | Boiler weight in the factory delivery volume, kg | 20750 |
| Basic kit assembled | Boiler block with casing and insulation, stairs, platforms, burner GM-10 | Additional equipment: |
| Economizer | BVES-IV-1 | Economizer | EB1-330 |
| Fan | VDN-9-1500 | Smoke exhauster | DN-11.2-1500 |
| Box No. 1 | Fittings for boiler DE-16-14GMO | Box No. 2 | Safety devices for boiler DE-16-14GMO |
PRODUCT DESCRIPTION
The combustion chamber of the boilers is located on the side of the convective beam, equipped with vertical pipes flared in the upper and lower drums. The width of the combustion chamber along the axes of the side screen pipes is the same for all boilers - 1790 mm. Combustion chamber depth: 1930 - 6960 mm. Main components boilers are upper and lower drums, a convective beam, front, side and rear screens that form the combustion chamber.
The pipes of the gas-tight partition and the right side screen, which also forms the ceiling of the combustion chamber, are inserted directly into the upper and lower drums. The ends of the rear screen pipes are welded to the upper and lower collectors Ф 159х6 mm. The front screen pipes of the DE-16-14GMO boiler are flared in the upper and lower drums.
In all standard sizes of DE boilers, the diameter of the upper and lower drums is 1000 mm. The distance between the axes of the drums is 2750 mm (the maximum possible under the conditions of transporting the block by rail). Length of the cylindrical part of the boiler drums with capacity
10 t/h - 6000 mm. For access to the inside of the drums, there are manhole gates in the front and rear bottoms of each of them. Drums for boilers with operating absolute pressure of 1.4 and 2.4 MPa (14 and 24 kgf/cm2) are manufactured from steel sheet according to GOST 5520-79 from steel grades 16GS and 09G2S GOST 19281-89 and have a wall thickness of 13 and 22 mm, respectively.
In the water space of the upper drum there is a feed pipe and a pipe for introducing phosphates, and in the steam volume there are separation devices. The lower drum contains a device for steam heating of water in the drum during kindling and pipes for draining water; for boilers with a capacity of 16 t/h, there are perforated pipes for periodic purging.
Boilers with a steam capacity of 16 t/h use two-stage evaporation. The second stage of evaporation includes the rear part of the furnace screens and part of the convective beam, located in a zone with more high temperature gases The second stage evaporation circuits have an unheated downdraft system.
The convective beam is separated from the combustion chamber by a gas-tight partition, in the rear part of which there is a window for the entry of gases into the beam. The partition is made of pipes Ø 51x2.5 mm placed closely with a pitch of 5 = 55 mm and welded together. When inserted into drums and pipes, they are separated into two rows. The distribution points are sealed with metal spacers and chamotte concrete. The convective bundle is formed by vertical pipes Ø 51 x 2.5 mm arranged in a corridor, flared in the upper and lower drums. The pitch of the pipes along the drum is 90 mm, the transverse pitch is 110 mm (except for the average pitch, which is 120 mm).
DE-16-14GMO boilers do not have stepped partitions in the beam, and the required level of gas velocities is maintained by changing the beam width from 890 to 1000 mm. Flue gases pass across the entire cross-section of the convective beam and exit through the front wall into the gas box, which is located above the combustion chamber, and through it they pass to the economizer located at the rear of the boiler.
All standard sizes of boilers have the same circulation circuit. The contours of the side screens and the convective beam of all standard sizes of boilers, as well as the front screen of boilers with a steam capacity of 16 t/h, are closed directly to the drums; the contours of the rear screen of all boilers are connected to the drum through intermediate collectors: the lower one is distributing (horizontal) and the upper one is collecting (inclined). The ends of the intermediate collectors on the side opposite to the drums are united by an unheated recirculation pipe Ф 76 x 3.5 mm.
As the primary separation devices of the first stage of evaporation, guide shields and canopies installed in the upper drum are used, ensuring the delivery of the steam-water mixture to the water level. A horizontal louvered separator and a perforated sheet are used as secondary separation devices of the first stage of the DE-16-14GMO boiler. The separation devices of the second stage of evaporation are longitudinal shields that ensure the movement of the steam-water mixture, first to the end, and then along the drum to the transverse partition separating the compartments. The staged evaporation compartments communicate with each other via steam through a window above the transverse partition, and via water through a feed pipe Ø 89 - 108 mm, located in the water volume.
On boilers with a capacity of 16 t/h, the superheater is vertical, drained, made of two rows of pipes Ø 51x2.5 mm, the outer row pipes when entering the collectors Ø 159 mm are cased to Ø 38 mm.
Dense shielding of the side walls (relative pitch of the pipes a = 1.08), ceiling and bottom of the combustion chamber makes it possible to use light insulation on boilers in two to three layers of insulating boards with a total thickness of 100 mm, laid on a layer of fireclay concrete on a grid 15-20 mm thick. For DE-16-14GMO boilers, the front wall lining is made of fireclay bricks 125 mm thick and several layers of insulating boards 175 mm thick, the total thickness of the front wall lining is 300 mm. The lining of the rear wall consists of a layer of fireclay bricks 65 mm thick and several layers of insulating boards 200 mm thick; the total thickness of the lining is 265 mm. To reduce suction into the gas path of the boiler, the insulation is covered from the outside with metal sheet cladding 2 mm thick, which is welded to the frame. Cut sheathing sheets are supplied by the factory in packages. The use of pipe lining with tight pipe spacing can improve dynamic characteristics boilers and significantly reduce heat loss to the environment, as well as losses during start-ups and shutdowns.
Standard cast iron economizers EB, proven by long-term operating experience, are used as tail heating surfaces of boilers.
The boilers are equipped with stationary blowers located on the left side of the boiler. For blowing boilers, saturated or superheated steam with a pressure of at least 0.7 MPa (7 kgf/cm2) is used.
All boilers have a support frame to which the mass of the boiler elements operating under pressure is transferred, the mass boiler water, as well as the mass of the strapping frame, pipe lining and lining. The fixed supports of the boilers are the front supports of the lower drum. The middle and rear supports of the lower drum are movable and have oval holes for bolts that are attached to the support frame during transportation.
Each boiler E (DE) is equipped with two spring safety valves, one of which is a control valve. On boilers without a superheater, both valves are installed on the upper drum of the boiler and any of them can be selected as a control valve; on boilers with a superheater, the control valve is the valve of the superheater outlet manifold.
Nominal steam output and steam parameters corresponding to GOST 3619-89,
are provided at a feed water temperature of 100°C when burning fuels: natural gas With specific heat combustion 29300 - 36000 kJ/kg (7000 - 8600 kcal/m3) and fuel oil grades 40 and 100 according to GOST 10588-75.
The control range is from 20 to 100% of the nominal steam output. Short-term operation with a load of 110% of the rated steam output is allowed. Maintaining the superheat temperature in boilers with steam superheaters is ensured in the load range of 70-100%
DE-16-14GMO boilers can operate in the pressure range of 0.7-1.4 MPa (7-14 kgf/cm2). With a decrease in operating pressure, the boiler efficiency does not decrease.
In boiler houses designed to produce saturated steam without imposing strict requirements on its quality, the steam production of DE type boilers at pressures reduced to 0.7 MPa (7 kgf/cm2) can be taken the same as at a pressure of 1.4 MPa ( 14 kgf/cm 2).
For type E (DE) boilers, the throughput of the safety valves corresponds to the rated output of the boiler at an absolute pressure of at least 0.8 MPa (8 kgf/cm2). If the heat-using equipment connected to the boiler has a maximum operating pressure less than the above values, additional safety valves should be installed on it to protect this equipment. When operating at reduced pressure, safety valves on the boiler and additional safety valves installed on the equipment must be adjusted to the actual operating pressure.
With a decrease in pressure in boilers to 0.7 MPa (7 kgf/cm2), changes in the configuration of boilers with economizers are not required, since in this case the underheating of water in feed economizers to the steam saturation temperature in the boiler is more than 20 ° C, which satisfies requirements of Rostechnadzor rules.
Boilers are supplied assembled as one transportable unit, including upper and lower drums with internal drum devices, a pipe system of screens and a convection beam (if necessary, a superheater), a support frame, a piping frame, casing, insulation, and a burner.
Steam boiler DE-16-14GM-O - gas-oil, vertical-water-tube steam boiler with natural circulation, the main elements of which are an upper drum, a lower drum, as well as a shielded combustion chamber and a convective beam.
Specifications boiler DE-16-14GM-O
| № | Name | Meaning |
| 1 | Boiler type | Steam |
| 2 | Type of design fuel | 1 - Gas; 2 - Liquid fuel |
| 3 | Steam capacity, t/h | 16 |
| 4 | Operating (excess) coolant pressure at the outlet, MPa (kgf/cm2) | 1,3(13,0) |
| 5 | Steam temperature at the outlet, °C | sat. 194 |
| 6 | Feedwater temperature, °C | 100 |
| 7 | Estimated efficiency (fuel No. 1), % | 93 |
| 8 | Estimated efficiency (fuel No. 2), % | 90 |
| 9 | Estimated fuel consumption (fuel No. 1), kg/h (m 3 / h - for gas and liquid fuel) | 1141 |
| 10 | Estimated fuel consumption (fuel No. 2), kg/h (m 3 /h - for gas and liquid fuel) | 1088 |
| 11 | Dimensions of transportable unit, LxBxH, mm | 7180x3030x4032 |
| 12 | Layout dimensions, LxBxH, mm | 8655x5240x6072 |
| 13 | Weight of the boiler without firebox (transportable boiler block), kg | 19130 |
| 14 | Weight of the boiler without firebox (in the scope of factory delivery), kg | 20750 |
| 15 | Type of delivery | Assembled |
Basic complete set:
Complete boiler block with casing and insulation
Stairs and landings
Burner GM-10
Additional equipment:
The DE-16-14GM-O boiler uses a single-stage evaporation system. The water circulates as follows: heated nutrient water is supplied to the upper drum under the water level. Water enters the lower drum through screen pipes. From the lower drum, water enters the convective beam, when heated, turning into a steam-water mixture, and rises to the upper drum.
The main components of the DE-16-14GM-O boiler are the upper and lower drums, a convective beam and forming the combustion chamber: the left combustion screen, the gas-tight partition, the right side screen, screening pipes for the front wall of the firebox and the rear screen.
The pipes of the partition and the right side screen, which also forms the under and ceiling of the combustion chamber, are inserted directly into the upper and lower drums. The ends of the pipes of the rear screen of the DE-16-14GM-O boiler are welded to the upper and lower manifolds. The boiler front screen pipes are welded to the collectors.
To burn fuel oil and natural gas, a GM-10 gas and oil burner is installed on the DE-16-14GM-O boiler.
Boiler drums DE-10-16-14GM-O:
Upper drum of boiler DE-16-14GM-O
Boiler bottom drum DE-16-14GM-O
Boiler hole DE-16-14GM-O
Pipe system of boiler DE-16-14GM-O:
Screen pipes of the boiler DE-16-14GM-O
Convective (boiler) pipes of the boiler DE-16-14GM-O
Descent and bypass pipes DE-16-14GM-O
Upper boiler manifold DE-16-14GM-O
Boiler lower manifold DE-16-14GM-O
Fittings and water indicators for boiler DE-16-14GM-O
| Flange with pipe | 1 |
| Flange | 1 |
| Stop valve Dy20 Py25 | 12 |
| Valve (valve) DN50 PN40 15s22nzh | 3 |
| Valve (valve) Du80 Ru40 15s22nzh | 3 |
| Valve Du50 Ru16 KRP-50M | 1 |
| Check valve Du32 Ru100 3S-6-3 | 1 |
| Rotary check valve Du80 Ru40 19s53nzh | 2 |
| Ball valve Du125 Ru16 KShZF | 1 |
| Flange 50a-(16-25) | 5 |
| Flange 80-16 | 5 |
| Flange 80-25 | 3 |
| Flange 125-16 | 1 |
| Fastening in a box (DE16-14GM-0) | 1 |
| Nozzle | 1 |
| Power pad with fastening loop | 2 |
| Support | 1 |
| Level column | 1 |
| Three-way valve Dy10 Рy40 | 1 |
| Level indicator Dy10 Py25 | 2 |
| Three-way tension valve with flange Du15 Pu16 (11B38bk3) | 1 |
| Flange ball valve Du25 Ru25 Tpr=250°C KShF | 2 |
| Safety valve Dy50 Py40 (dс=48) | 2 |
| Flange 25-25 | 2 |
| Lid | 2 |
| SLEEVE | 2 |
| Pressure gauge tube | 1 |
| Stopper | 2 |
| Gasket 58Х33 (permanent sheet) | 4 |
| Pad | 2 |
| Pad | 2 |
| Cartridge | 2 |
| Pressure gauge MP4-U U2-2.5MPa-1.5 | 2 |
| Flange 100-16 | 2 |
Federal Agency for Education Russian Federation
State educational institution of higher professional education
Moscow Academy of Public Utilities and Construction
Faculty of Engineering Systems and Ecology
Department of Heat and Gas Supply and Ventilation
Course project
discipline: Heat generating installations
on the topic: Thermal calculation of boiler DE16 - 14GM
Moscow, 2011
Introduction
Gas-oil vertical water tube steam boiler type DE16 t/h is designed to produce saturated and slightly superheated steam used for the technological needs of industrial enterprises, heating, ventilation and hot water supply systems. The combustion chamber of the boiler is located on the side of the convective beam formed by vertical tubes flared in the upper and lower drums. The width of the combustion chamber along the axes of the side screen pipes is 1790 mm. The main components of the boilers are the upper and lower drums, the convective beam, the front, side and rear screens that form the combustion chamber. The pipes of the right side screen, which also forms the floor and ceiling of the combustion chamber, are inserted directly into the upper and lower drums. The front screen pipes are flared in the upper and lower drums. The diameter of the upper and lower drums is 1000 mm. The vertical distance between the drums is 2750 mm. The length of the cylindrical part of the drums is 7500 mm. To access the inside of the drums, there are special holes in the front and rear bottoms of each of them. The material of the drums for boilers with a working pressure of 1.36 MPa and 2.36 MPa is 16GS steel, wall thickness is 13 and 22 mm, respectively. In the water space of the upper drum there is a feed pipe and a pipe for introducing phosphates, and in the steam volume there are separation devices. The lower drum contains perforated pipes for purging, a device for steam heating of water in the drum during kindling, and pipes for draining water.
Boilers with a steam capacity of 16 t/h have continuous blowing from the second stage of evaporation (salt compartment) of the upper drum and periodic purging from the lower drum of the lower manifold of the rear screen, if available. DE16-14GM boilers are made with a two-stage evaporation scheme. The second stage of evaporation, using transverse partitions in the drums, includes the rear part of the right and left furnace screens, the rear screen and part of the convective beam located in the zone with a higher gas temperature. The second evaporation stage is fed from the first through a bypass pipe with a diameter of 108 mm, passing through the transverse dividing wall of the upper drum. The second stage evaporation circuit has unheated downpipes with a diameter of 159x4.5 mm. The descending link of the circulation circuits of the boilers and the first stage of evaporation are the last, least heated rows of convective bundle pipes along the gas flow. The convective beam is separated from the combustion chamber by a gas-tight partition, in the rear part of which there is a window for gases to enter the beam. The partition is made of pipes with a diameter of 51 x 2.5 mm placed closely (S = 55 mm) and welded together. When inserted into the drums, the pipes are separated into two rows. The wiring points are sealed with metal spacers and chamocrete. Flue gases exit the boilers through a window in the left side wall at the end of the convective beam. All standard sizes of boilers have the same circulation circuit. The contour of the side screens and the convective beam are closed directly to the drum.
The superheater is vertical, drained from two rows of pipes with a diameter of 51 x 2.5 mm.
The lining of the front wall is made of fireclay bricks 125 mm thick and several layers of insulating boards 175 mm thick, the total thickness of the front wall lining is 300 mm; the lining of the rear wall consists of a layer of fireclay bricks 65 mm thick and several layers of insulating boards 200 mm thick. The total thickness of the lining is 265 mm. To reduce suction, the gas path of the boiler outside the insulation is covered with metal sheet cladding 2 mm thick, which is welded to the framing frame.
Cast iron economizers made from VTI pipes are used as boiler tail heating surfaces.
The boilers are equipped with stationary blowers located on the left side of them. For blowing boilers, saturated or superheated steam with a pressure of at least 0.7 MPa is used.
Each DE boiler is equipped with two spring safety valves, one of which is a control valve.
Load control range 20-100% of rated steam output. Operation with a load of 110% of the rated steam output is allowed.
Initial data
Steam capacity - 16 t/h (4.44 kg/s)
Pressure - 1.4 MPa (14 atm)
Feedwater temperature - 95°C
Type of fuel - low-sulfur fuel oil.
Air temperature at the boiler inlet -
Heat capacity of air at -
Flue gas temperature - 200°C
Dry residue of source water - 400 mg/kg
The percentage of condensate return is 50%.
Design characteristics of the DE16-14GM boiler unit:
Firebox volume according to drawings
Full surface of furnace walls according to drawings 
Beam-receiving surface of the firebox 
Convection pipe diameter 
Transverse pipe pitch
Pipe pitch longitudinal
Average pipe height
Flue width
Average flue height
Number of pipes in a row of a flue
Number of rows of flue pipes
Cross section for the passage of gases of the flue 
Beam heating surface 
1.
Calculation of volumes of air and combustion products
Net calorific value of liquid fuel:
Theoretical amount of air required to burn 1 m3 of fuel:
The theoretical amount of combustion products formed when burning liquid fuel at an excess air ratio:
Triatomic gases:
diatomic gases:
water vapor:
With excess air ratio >1
The value of the coefficient of excess air in the furnace:
Boiler flue:
Economizer:
The volume of excess air in the combustion products in the boiler elements will be:
Gas flue
Economizer
Excessive volume of water vapor in combustion products by boiler elements:
Gas flue
Economizer
Actual total volume flue gases by boiler elements:
Gas flue
Economizer
Volume fraction of triatomic gases by boiler elements:
Gas flue
Economizer
Volume fraction of water vapor by boiler elements:
Gas flue
Economizer
Total volume fraction for boiler elements:
Gas flue
Economizer
2. Enthalpy of air and combustion products
where , , , are the specific heat capacities of triatomic gases, water vapor, diatomic gases (nitrogen) and air, respectively; their values are given in the table.
Enthalpy of air at the entrance to the boiler:
Enthalpy of the theoretically required volume of air.
Combustion chamber:
Boiler flue:
Economizer:
Enthalpy of the theoretically required volume of combustion products.
Combustion chamber:
Boiler flue:
Economizer:
Enthalpy of combustion products with excess air.
where is the enthalpy of excess air at a temperature corresponding to the temperature of the combustion products.
Combustion chamber:
Boiler flue:
Economizer:
3. Estimated heat balance and fuel consumption
The heat balance of a boiler unit is the equality between the heat supplied to it and the sum of the useful heat generated and the heat spent to cover heat losses. The heat entering the boiler unit is called available heat.
where is the lower calorific value of the working mass of fuel, kJ/kg;
Heat introduced into the boiler unit by air when heating it outside the unit, kJ/kg:
where is the excess air coefficient;
Heat content of the theoretically required amount of air at the entrance to the boiler unit and cold air, kJ/kg;
Physical heat contributed by fuel, kJ/kg:
Where - specific heat working fuel, kJ/(kg K);
Fuel temperature, єС, (for fuel oil is taken depending on its viscosity 90-130 єС:
Heat introduced into the unit during steam spraying of liquid fuel, kJ/kg:
where is the enthalpy of steam used for fuel atomization, kJ/kg.
DE series boilers are equipped with gas-oil burners of the GMGm type, with steam-mechanical atomization with insignificant steam consumption, so the value can be neglected.
The heat balance is compiled for a boiler unit per 1 kg of liquid or 1 m3 of gaseous fuel under normal conditions.
The equation heat balance:
where is the useful heat generated by the boiler unit, kJ/kg;
Heat loss with exhaust combustion products, kJ/kg:
where is the enthalpy of exhaust gases, determined by h-t diagram, at the corresponding values of the excess air coefficient behind the boiler and the selected flue gas temperature, kJ/kg;
Enthalpy of the theoretically required volume of cold air, determined at the temperature of the air entering the boiler.
Heat loss from chemical incomplete combustion, kJ/kg;
Heat loss from mechanical incomplete combustion occurs only when burning solid fuel;
Heat loss to the environment (from external cooling), kJ/kg;
Physical heat contributed by fuel during fuel combustion. Can be ignored.
Calculation of the heat balance of the boiler unit.
Enthalpy of air at the inlet to the boiler with the heat capacity of the air at the inlet to the boiler:
Exhaust gas enthalpy:
Heat loss with flue gases:
Heat loss from chemical heat of combustion according to the standard method:
Heat loss from mechanical underburning according to the standard method:
Heat losses from losses to the environment according to the standard method:
Amount of heat losses:
Boiler efficiency:
Fuel calculation.
Boiler steam output - 
.
Feed water temperature at the water economizer inlet:
Enthalpy of feed water at the inlet to the water economizer:
Enthalpy of steam behind the boiler:
Useful boiler power:
Fuel consumption:
Heat retention coefficient in the firebox:
4. Verification calculation of the combustion chamber
A verification calculation of the furnace of a boiler unit is carried out in order to determine the parameters characterizing the thermal operating conditions of the furnace. The compliance of the temperature of the combustion products at the furnace outlet with the operating conditions is checked.
Flue gas temperature:
Total area of the furnace walls (total area of all surfaces limiting the volume of the combustion chamber (screened and unscreened walls, vault, exit window, floor, etc.)):
Area of the beam-receiving surface of the firebox:
Combustion chamber volume:
Firebox screening degree:
air combustion thermal boiler
Coefficient of contamination or closure of screens (takes into account the decrease in heat absorption of screens due to their contamination or the covering of their surface with a refractory mass):
The average value of the thermal efficiency coefficient of the entire firebox:
Temperature field parameter in the furnace:
Effective thickness of the radiating layer:
Net heat release in the firebox:
Theoretical (adiabatic) combustion temperature according to h-t chart diagrams:
Average total heat capacity of combustion products:
where is the enthalpy of combustion products at the exit from the furnace at accepted temperature combustion behind the firebox with subsequent clarification.
The pressure in the combustion chamber (for fireboxes operating without pressurization) is assumed to be -.
Total partial pressure of triatomic gases in the furnace:
Volume fraction of furnace water vapor - 
:
Blackness level of the non-luminous part of the flame:
where , is the content of carbon and hydrogen in the working mass of liquid fuel;
The coefficient of excess air in the furnace.
Attenuation coefficient of the luminous part of the gas-oil flame:
Blackness degree of the luminous part of the flame:
Blackness level of the firebox.
where is the coefficient of filling the furnace volume with a luminous flame (depends on the thermal voltage of the furnace volume and the type of compressed fuel, so for 
regardless of the load for liquid fuel. At , for liquid fuel).
When the coefficient is:
Since the difference between the calculated temperature and the previously set temperature is more than 50°C, a repeated calculation is carried out using the obtained calculated value.
Average total heat capacity of combustion products:
Coefficient of attenuation of rays by triatomic gases:
Coefficient of attenuation of rays by the non-luminous part of the combustion environment:
Blackness level of the non-luminous part of the flame:
Coefficient of attenuation of rays by soot particles:
Attenuation coefficient of the luminous part of the gas-oil flame:
Blackness degree of the luminous part of the flame:
Blackness level of the firebox.
where is the effective degree of blackness of the firebox:
Estimated temperature of flue gases at the furnace outlet:
The temperature falls within the interval, we consider it valid.
Enthalpy of combustion products at the exit from the furnace -
Heat transferred by radiation:
Specific load of the beam-receiving heating surface:
5. Verification thermal calculation of convective heating surfaces
We set two temperatures of the combustion products at the excess air coefficient in the boiler flue: :
Heat given off by combustion products:
where is the heat conservation coefficient;
air suction into the convective heating surface, defined as the difference in the coefficients of excess air at the inlet and outlet of it;
enthalpy of air sucked into the convective surface, at air temperature;
Enthalpy of combustion products in front of the heating surface at ;
Enthalpy of combustion products after the calculated heating surface, determined for two previously accepted temperatures after the convective heating surface:
Temperature pressure in the flue:
where is the temperature of combustion products in front of the design gas duct;
- the temperature of the cooling medium, for steam boilers, is assumed to be equal to the boiling point of water at the actual pressure in the boiler (Appendix 1 - table of saturated water vapor).
Average temperature of combustion products in the flue:
Average speed of combustion products in the flue:
Where 
- fuel consumption;
- the actual total volume of flue gases in the flue generated during the combustion of 1 kg of liquid fuel with the corresponding excess air ratio;
- open cross-sectional area for the passage of combustion products during transverse flow of smooth pipes.
Heat transfer coefficient by convection from combustion products to the heating surface:
where is the correction for the number of rows of pipes along the flow of combustion products, determined by transverse washing of corridor bundles according to the nomogram (Fig. 3 of the “Training aid for course work”);
The correction for the beam arrangement is determined according to the nomogram (Fig. 3 of the “Teaching and methodological manual for course work”):
The coefficient taking into account the influence of changes in the physical parameters of the flow is determined during the transverse washing of corridor beams according to the nomogram (Fig. 3 of the “Training and methodological manual for course work”):
at 
- ,
at 
- ;
Heat transfer coefficient determined by nomogram (Fig. 3 of the “Teaching and methodological manual for course work”):
at 
- 
,
at 
- 
.
Thickness of the radiating layer for smooth tube bundles:
The pressure in the gas duct (for boilers operating without pressurization) is assumed to be -.
The total volume fraction of triatomic gases is .
Total partial pressure of triatomic gases in the flue:
Attenuation coefficient by triatomic gases:
Total optical thickness:
Blackness degree of the gas flow:
Contaminated wall temperature:
Where - the temperature of the cooling medium, for steam boilers, is assumed to be equal to the boiling point of water at the actual pressure in the boiler (Appendix 1 - table of saturated water vapor). and is the enthalpy of combustion products after the calculated heating surface at
Ministry of Education and Science of the Russian Federation
Federal State Budgetary Educational Institution
Higher Professional Education
"Magnitogorsk State Technical University named after G.I. Nosov"
(FSBEI HPE "MSTU")
Department
course work
in the discipline: “Heat generating installations”
on the topic: “Thermal calculation of the boiler DE-16-14GM”
Performer: Pivkin A.A., 4th year student, group SO-12
Head: Trubitsyna G.N., Ph.D. tech. Sci., Associate Professor
The work was approved for protection “”20.
(signature)
The work is protected "" 20g. with assessment
(signature)
Magnitogorsk 2016
Ministry of Education and Science of the Russian Federation
Federal State Budgetary Educational Institution
higher professional education
"Magnitogorsk State Technical University
Them. G. I. Nosova"
(FSBEI HPE "MSTU")
Department "Heat and gas supply, ventilation and
Water supply, sanitation"
ASSIGNMENT FOR COURSE WORK
Student
(Full Name)
Initial data:
Due date: " " 20 g
Supervisor: / /
Received the task: / /
(signature) (signature decryption)
Magnitogorsk 2016
| EXERCISE | |
| 1. INITIAL DATA | |
| 2. CONSTRUCTION AND OPERATION OF BOILER DE-16-14 GM | |
| 2.1. General form | |
| 2.2. Description | |
| 2.4. Boiler drum DE-16-14 GM | |
| 2.5. Automatic boiler DE-16-14 GM | |
| 2.6.Water economizer | |
| 2.6.1. Cast iron economizers | |
| 2.6.2. Modifications | |
| 2.6.3. Characteristics of cast iron economizers | |
| 3.CALCULATION OF VOLUME AND ENTHALPY OF COMBUSTION PRODUCTS AND AIR | |
| 3.1. Calculation of volumes of combustion products and air. | |
| 3.2. Calculation of combustion products in heating surfaces | |
| 3.3. Calculation of enthalpies of combustion products and air | |
| 4. HEAT BALANCE OF THE BOILER UNIT | |
| 5.CALCULATION OF HEAT TRANSFER IN HEATING SURFACES | |
| 5.1. Calibration thermal calculation of the combustion chamber | |
| BIBLIOGRAPHY |
EXERCISE
It is necessary to carry out a verification calculation of a DE-16 type boiler unit with elements constructive calculation separate heating surfaces (water economizer). The main purpose of the verification calculation is to determine the main performance indicators of the boiler unit, as well as design measures that ensure high reliability and efficiency of its operation under given conditions.
INITIAL DATA
Boiler unit DE-16-14 GM on gas and liquid fuel, brand GM (gas-oil burner), Russian Federation, Saratov region, natural gas from the Saratov-Gorky gas pipeline.
Table 1
Design characteristics of steam boiler type DE-16-14 GM
Biysk Boiler Plant
| № | Indicator name | Meaning |
| Steam capacity, | ||
| Steam pressure at the boiler outlet, (kgf/cm2) | ||
| Steam temperature | ||
| Feed water temperature, | ||
| Flue gas temperature, | ||
| Type of design fuel | Natural gas | |
| Fuel consumption |  |
|
| Combustion device type | TLZM | |
| Surface area of the combustion mirror, m 2 | 6,39 | |
| Combustion chamber volume, m 3 | 22,5 | |
| Radiation heating surface area, m 2 | 30,3 | |
| Heating surface area of the convective beam, m2 | 207,3 | |
| Outside diameter convective bundle tubes, m | 0,051 | |
| Transverse pipe pitch, m | 0,11 | |
| Longitudinal pitch of pipes, m | 0,09 | |
| Number of rows of pipes, pcs | ||
| Length of one water economizer pipe, m | 1,5 | |
| Gross boiler efficiency, | ||
| dimensions boiler mm: length width height | 8655 5205 6050 |
table 2
Operating fuel weight
| Chemical composition | ||||||
| methane | ethane | propane | butane | pentane | nitrogen | carbon dioxide |
| 91,9% | 2,1% | 1,3% | 0,4% | 0,1% | 3% | 1,2% |
| Heat of combustion 8630 kJ/m³ | Density 0.786 kg/m³ |
CONSTRUCTION AND OPERATION OF BOILER DE-16-14 GM
2.1. General view of the boiler
A longitudinal section drawing of the DE-16 boiler is given in Appendix 1.
2.2. Description
Steam boiler DE-16-14 GM oil-gas vertical water tube with natural circulation type E (DE) with a capacity of 16 tons of saturated steam (194 °C) per hour, used for the technological needs of industrial enterprises, in heating, ventilation and hot water supply systems. The combustion chamber of the DE boiler in the form of a Latin “D” is formed by screen pipes and is located to the right of the convective beam, equipped with vertical pipes flared in the upper and lower drums. The main components of the DE-16-14GM boiler are the upper and lower drums, the pipe system of the DE boiler consists of a convective beam, a rear front and side screen, forming the combustion chamber of the DE-16-14GM boiler.
Boiler DE-16 14 GM with a steam capacity of up to 16 t/h with a diameter of the upper and lower drums of 1000 mm. The distance between the drums is 1700 mm and 2750 mm, respectively (the maximum possible according to the conditions for transporting the block by railway). To access the inside of the drums, there are manholes with shutters in the front and rear bottoms of each of them (manhole cover). Drums for boilers with a working pressure of 1.4 MPa (abs) are made from steel 16GS or 09G2S and have a wall thickness of 13 mm, respectively.
Steam boiler DE-16 14 GM with a capacity of 16 and 25 t/h with a two-stage evaporation scheme. The second evaporation stage includes the rear part of the furnace screens and part of the convective beam, located in the zone with a higher gas temperature. The second stage evaporation circuits have an unheated descent system.
On boilers with a capacity of 16 and 25 t/h, the superheater is vertical, drained from two rows of pipes.
The DE-16-14 GM boiler is supplied both in blocks and in bulk; upper and lower drums with intra-drum devices, a pipe system of screens and a convective beam (if necessary, a superheater), support frame, insulation and casing.
Steel BWES or cast iron EB economizers are used as boiler tail heating surfaces.
The DE 16 14 GM steam boiler is equipped with heating surface cleaning systems using a GUV (shock wave generator).
The fixed supports of the boilers are the front supports of the lower drum. The middle and rear supports of the lower drum are movable and have oval holes for bolts that are attached to the support frame during transportation.
The DE-16-14 GM boiler is equipped with two 17s28nzh spring safety valves, one of which is a control valve. On boilers without a superheater, both valves are installed on the upper drum of the boiler and either of them can be selected as a control valve. On boilers with a superheater, the control valve is the superheater outlet manifold valve.
Nominal steam output and steam parameters (corresponding to GOST 3619-82) are provided at a feed water temperature of 100°C when burning fuels: natural gas with a specific heat of combustion of 29300-36000 kJ/kg (7000-8600 kcal/m3) and fuel oil grades M40 and M100 according to GOST 10588-75.
The control range is 20-100% of the nominal steam output. Short-term operation with a load of 110% is allowed. Maintaining the superheat temperature in boilers with superheaters is ensured in the load range of 70-100%.
The DE-16-14 GM boiler can operate in the pressure range of 0.7-1.4 MPa.
In boiler houses designed to produce saturated steam without imposing strict requirements on its quality, the steam production of type E (DE) boilers at a pressure reduced to 0.7 MPa can be taken the same as at a pressure of 1.4 MPa.
For the DE-16-14 GM boiler, the throughput of safety valves 17s28nzh corresponds to the nominal output of the boiler at a pressure of at least 0.8 MPa (abs).
The quality standards of feedwater and steam must comply with the requirements regulated by the rules of the Federal Service for Environmental, Technological and Nuclear Supervision of Russia.
Average boiler service life between major repairs at number of hours of use installed capacity 2500 h/y - 3 years, average service life before write-off is at least 20 years.
Steam boiler DE-16-14 GM can be used as a hot water boiler (according to the technical documentation of the enterprise).
2.3. Pipe system of the boiler DE-16-14 GM
Convective pipes DE-16-14 GM and screen pipes DE-16 14 GM are made exclusively from seamless boiler pipe with a diameter of 51 mm and a wall thickness of 2.5 mm. Since the weld can become a concentrator of internal stresses and lead to a decrease in corrosion resistance, strength and even destruction of the product. Boiler pipes are produced by cold or hot deformation, which provides excellent quality and durability results. For convective pipe DE-16-14 GM and screen pipe DE-16 14 GM, GOST 8734-75 or GOST 8731-74 is used (steel grades: St10, St15, St20, St25 and wall thickness from 2.5 to 13 mm, respectively) . As a rule, convective pipes DE-16-14 GM and screen pipes DE-16 14 GM are used in conditions of high and supercritical steam parameters. In this case, a subtype of boiler pipe rolling is used: pipes for steam boilers; they best meet these conditions. The pipe for the boiler pipe system DE-16 14 GM is manufactured by hot rolling on a continuous mill and by hot pressing, which ensures excellent result at any temperature. The combustion chamber of the DE-16 14 GM boiler is formed from screen pipes flared in the upper and lower drum of the DE-16 14 GM boiler in the form of the Latin letter "D".
2.4. Boiler drum DE-16
The DE-16 boiler drum, operating pressure 1.4 MPa, is made of steel 16GS, 09G2S, wall thickness is 13 and 22 mm, respectively. The technology for manufacturing the drums of the DE-16-14 boiler is similar to the original factory technology; cutting sheet metal, processing sheet edges for welding, rolling sheets with rollers to obtain shells for the future drum of the DE-16 14 GM boiler, welding shells and bottoms under submerged arc using welding machine, drilling holes for a boiler pipe ø 51 mm, using the milling method with subsequent rolling of the hole, which when rolling the pipe in a drum when installing the DE-16-14 GM boiler, gives a more reliable connection when checking the hydraulic test of the DE-16 14 GM boiler. Control of welds is ensured by ultrasonic diagnostics of the DE-16 14 GM boiler drum. How finished product The drum of the DE-4 boiler is assigned and stamped with a serial number, and stamps are placed with a certificate and permission to use "ROSTEKHNADZOR" attached. For inspection of DE boiler drums and devices located in them, as well as for cleaning pipes with rollers, there are manholes on the rear bottoms; boilers DE-16 and DE-10 with a long drum have another hole on the front bottom of the upper drum.
On the upper part of the upper drum of the DE-16-14 boiler, pipes are welded for installing safety valves, the main steam valve or gate valve, valves for sampling steam, and extracting steam for auxiliary needs (blowing).
In the water space of the upper drum of the DE-16 boiler there is a feed pipe, and in the steam volume of the drum there is a steam separation device. The lower drum of the DE-16 14 GM boiler contains a perforated pipe for purging, a device for heating the drum during lighting (for boilers with a capacity of 16 t/h and above) and a fitting for draining water.
To monitor the water level in the upper drum of the DE-16 boiler, two level indicators are installed.
On the front bottom of the upper drum of the DE-16 boiler there are two fittings for selecting water level pulses for the boiler automation.
2.5. Automatic boiler DE-16-14 GM
Boiler automation functions:
1.Measurement and signaling: boiler automation DEV-16 14 GM using light and sound alarm when technological parameters deviate from the norm.
2. Ignition and shutdown of the boiler: the automation of the water heating boiler DE-16 14 GM automatically ignites and stops the boiler, without the participation of maintenance personnel, which meets the requirements of the rules of PB 12-529-03.
3. Regulation of the combustion process: automatic regulation of the fuel supply to the boiler furnace depending on the temperature of the water leaving the boiler;
4. Vacuum: the automatic control of the DEV 16 14 GM boiler provides regulation of the vacuum in the boiler furnace, the fuel-air ratio using MEO or frequency converters installed on the fan (VDN) and smoke exhauster (DN).
5. Protection: the automation of the water heating boiler DE-16 14 GM ensures that the boiler stops if the specified technological parameters change:
● when the water temperature at the boiler outlet increases,
● when decreasing air pressure,
● when there is a deviation in gas pressure in front of the burner,
● when the vacuum in the boiler furnace decreases,
● when there is a deviation in water pressure at the boiler outlet,
● when the fuel pressure in front of the burner decreases,
● when the water flow through the boiler decreases,
● when the burner flame goes out,
● when voltage disappears in the protection circuits,
● in case of emergency stop of the fan and smoke exhauster,
6.Measurement and signaling: automatic boiler DEV-16-14 GM provides measurement and signaling of boiler operating parameters:
● water pressure at the boiler inlet;
● water pressure at the boiler outlet,
● water temperature at the boiler inlet,
● temperature of water leaving the boiler,
● air pressure in front of the burner,
● vacuum in the boiler furnace,
● water flow through the boiler,
● flue gas temperature.
7. “Upper level” control (optional): when equipping the automation system of the water heating boiler DE 16 14 GM with “upper level” control, it is implemented;
● presentation of information about the operation of the boiler on a computer monitor in the form of mnemonic diagrams and graphs,
● boiler control,
● archiving and registration of parameters.
In the boiler automation system DEV-16-14 GM, as required by PB 10-574-03, an electronic recorder is installed - a four-channel “Termodat17M5”, which records the root cause of the accident.
Water economizer
Cast iron economizers
A water economizer is a tubular heat exchanger in which feed water is heated to a temperature of 30 - 40 o C below the boiling point before entering the boiler in order to prevent steam formation and hydraulic shocks inside it. Heating occurs due to the heat of exhaust gases, thereby increasing the efficiency of the boiler unit.
Modifications
An example of a symbol for cast iron economizers:
EB1-300I(P) – economizer unit with one column, heating surface area of 300 m2 and gas pulse (I) or steam (P) cleaning.
Figure 1. Block single-column cast iron water economizer.
A – longitudinal section; B – cross section; 1 – damper; 2 – blowing device; 3 – cast iron finned pipes; 4 – gas duct.
In steam boilers, the temperature of the heat-receiving wall throughout the entire unit is almost the same and slightly exceeds the boiling point. As the steam pressure increases, the wall temperature rises, resulting in an increase in the flue gas temperature. It is irrational to release gases with such a high temperature into the atmosphere. Devices designed to solve this problem include economizers.
Cast iron block economizers are used as tail heating surfaces of stationary steam boilers of types DE, KE and DKVR.
Economizers are installed individually on a boiler or on a group of boilers low pressure(up to 2.4 MPa) and low power and can be disconnected from the boilers both through the gas and water paths.
Economizers of this type made from cast iron ribbed pipes with flanges, which are connected to each other using cast iron rolls (arcs). Fin length cast iron pipes The economizer is 2 or 3 m, the pipe diameter is 76x8 mm, the connecting flange is square with dimensions of 150 x 150 mm. The total heating surface area of the pipe is respectively 2.95; 4.49 m2.
Rice. 2. Parts of a cast iron water economizer.
A– finned tube; B– connecting pipes using a roller (arc).
Number of pipes in a package horizontal plane determined based on the speed of combustion products, usually in the range of 6-9 m/s; the number of horizontal rows is determined by the required total heating surface.
Water moves sequentially through all pipes from bottom to top, and combustion products pass through the gaps between the ribs of the pipes from top to bottom. With this pattern of water movement (lifting), better removal of air bubbles is ensured. To remove possible deposits, the outer surfaces of economizers are periodically blown with steam (P) using blowers or compressed air(gas pulse (I) cleaning).
Rice. 5. Movement of water and combustion products in the economizer.
To ensure reliable operation, the necessary fittings are installed at the inlet and outlet - safety valves and shut-off valves, thermometers, pressure gauge, drain valve, check valve, and at the top point of the economizer there are plungers to remove air.
Rice. 6. Connection diagram for a cast iron economizer.
1 – boiler drum;
2 – shut-off valve;
3 – check valve;
4 – valve on the discharge line; 5 – safety valve; 6 – air vent valve; 7 – cast iron water economizer; 8 – drain valve.
Cast iron economizers are supplied either in the form of separate parts with assembly on site, or in the form of transportable blocks in lightweight lining with metal lining.
Economizers EB2-94I(P) - EB2-236I(P) are supplied in one block, EB1-300I(P) and EB1-330I(P) - in two blocks, EB1-646I(P) and EB1-808I(P) - in three blocks.
The advantage of cast iron economizers: the use of cast iron in heating surfaces and connecting parts significantly increases service life due to its resistance to corrosion, both on the internal and external surfaces.
TECHNICAL DESCRIPTION DE TYPE BOILERS
Purpose, technical data and design of DE type boilers
DE steam boilers are designed to produce saturated or superheated steam used for the technological needs of industrial enterprises, as well as heating, ventilation and hot water supply systems.
The main characteristics and parameters of the boilers are given in Table 1.
Double-drum vertical water-tube boilers are made according to the design diagram “D”, characteristic feature which is the lateral location of the combustion chamber relative to the convective part of the boiler.
The main components of the boilers are the upper and lower drums, the convection beam and the left combustion screen (gas-tight partition), the right and rear combustion screens that form the combustion chamber, as well as the screening pipes for the front wall of the firebox.
In all boiler sizes inner diameter the upper and lower drums are 1000 mm. The length of the cylindrical part of the drums increases with increasing boiler steam production from 2250 mm for 4 t/h boilers to 7500 mm for 25 t/h boilers. The distance between the drum axes is 2750 mm.
The drums are made of sheet steel grade 16GS GOST5520-79 with a thickness of 13 and 22 mm for boilers with an operating absolute pressure of 1.4 and 2.4 MPa, respectively (14 and 24 kgf/cm 2 ).
For access to the inside of the drums, there are manholes in the front and rear bottoms.
The convective beam is formed by vertical pipes Ø51x2.5 mm located along the entire length of the cylindrical part of the drums, connected to the upper and lower drums.
The width of the convective beam is 1000 mm for boilers with a steam capacity of 10; 25 t/h and 890 mm - for other boilers.
The longitudinal pitch of the convective bundle pipes is 90 mm, the transverse pitch is 110 mm (except for the average pitch located along the axis of the drums, equal to 120 mm). The pipes of the outer row of the convective bundle are installed with a longitudinal pitch of 55 mm; When entering the drums, the pipes are separated into two rows of holes.
In convective bundles of boilers 4; 6.5 and 10 t/h, longitudinal cast iron or stepped steel partitions are installed. Boilers 16 and 25 t/h do not have partitions in the bundle.
The convective beam is separated from the combustion chamber by a gas-tight partition (left combustion screen), in the rear part of which there is a window for gases to enter the beam.
The pipes of the gas-tight partition, the right side screen, which also forms under the ceiling of the combustion chamber, and the pipes of the front wall screening are inserted directly into the upper and lower drums.
The cross-section of the combustion chamber is the same for all boilers. Its average height is 2400 mm, width - 1790 mm. The depth of the combustion chamber increases with increasing boiler steam production from 1930 mm for DE - 4 t/h to 6960 mm for DE - 25 t/h.
|
Factory designation of standard sizes |
Paro productivity, t/h |
Boiler operating pressure MPa (kgf/cm2) |
State or temperature of steam, °C |
Total heating surface, m 2 |
Boiler water volume, m 3 |
Steam volume of the boiler, m 3 |
Dimensions of the transportable unit |
Boiler dimensions by boiler cell |
Weight of transportable boiler block, kg |
Boiler weight as supplied by the plant, kg |
Type of gas and oil burner |
Estimated fuel consumption for separate combustion |
Accessories |
||||||||
|
economizer |
fan |
||||||||||||||||||||
|
Fuel oil, kg/h |
Gas, m 3 / h |
||||||||||||||||||||
|
DE-4-14GM-O/R / |
saturated |
EB2-94I (BVES-1-2) |
|||||||||||||||||||
|
DE-4-14-225GM-O |
overheated 225(+25;-10) |
||||||||||||||||||||
|
DE-6.5-14GM-O/R / |
saturated |
EB2-142I (BVES-2-2) |
VDN-11.2-1000 |
||||||||||||||||||
|
DE-6.5-14-225GM-O |
overheated 225(+25;-10) |
||||||||||||||||||||
|
DE-10-14GM-O/R / |
saturated |
EB2-236I (BVES-3-2) |
|||||||||||||||||||
|
DE-10-14-225GM-O |
overheated 225(+25;-10) |
||||||||||||||||||||
|
DE-10-24GM-O |
saturated |
||||||||||||||||||||
|
DE-10-24-250GM-O |
overheated 250(+25;-10) |
||||||||||||||||||||
|
DE-16-14GM-O/R / |
saturated |
EB2-330I (BVES-4-1) |
VDN-11.2-1500 |
||||||||||||||||||
|
DE-16-14-225GM-O |
overheated 225(+25;-10) |
||||||||||||||||||||
|
DE-16-24GM-O |
saturated |
||||||||||||||||||||
|
DE-16-24-250GM-O |
overheated 250(+25;-10) |
||||||||||||||||||||
|
DE-25-14GM-O/R / |
saturated |
EB2-808I (BVES-5-1) |
VDN-11.2-1500 |
||||||||||||||||||
|
DE-25-14-225GM-O |
overheated 225(+25;-10) |
||||||||||||||||||||
|
DE-25-15-270GM-O |
overheated 270(+25;-10) |
||||||||||||||||||||
|
DE-25-15-285GM |
overheated 285(+25;-10) |
||||||||||||||||||||
|
DE-25-24GM-O |
saturated |
||||||||||||||||||||
|
DE-25-24-250GM-O |
overheated 250(+25;-10) |
||||||||||||||||||||
|
DE-25-24-380GM-O |
overheated 270(+25;-10) |
VDN-12.5-1500 |
|||||||||||||||||||
Table 1
To the table
The minimum steam load of boilers, depending on the state of the burner, is 20-30% of the calculated one.
The maximum steam load of boilers, taking into account sufficient blast and draft (short-term) for boilers DE-4-10GM-120% of the calculated one; for boilers DE16-25GM-110% of the calculated value.
Feed water temperature - 100°C (+10; -10).
The temperature of the blast air in front of the burner is not lower than 10°C.
The letter “O” in the factory designation of boilers means: a boiler with casing and insulation.
When equipping boilers operating on fuel oil with a steel economizer, in order to increase the service life of the latter, it is necessary to provide additional feedwater heaters that ensure heating of the water in front of the economizer to 130°C (to increase the temperature of the wall of the economizer coils). This is due to the low-temperature, sulfurous corrosion that occurs under these conditions, which occurs intensively when sulfurous acid condenses onto colder metal walls below the dew point.
The plant can equip boilers with a steam capacity of 4; 10 t/h compact steel economizers supplied as one unit with the boiler and feedwater heaters installed in the lower drum.
The pipes of the right combustion screen Ø51x2.5 mm are installed with a longitudinal pitch of 55 mm; When entering the drums, the pipes are separated into two rows of holes.
The shielding of the front wall is made of pipes Ø51x2.5 mm.
The gas-tight partition is made of pipes Ø51x2.5 mm or Ø51x4 mm, installed at 55 mm intervals. At the entrance to the drums, the pipes are also separated into two rows of holes. The vertical part of the partition is sealed with metal spacers welded between the pipes. The pipe distribution areas at the entrance to the drums are sealed with metal plates and chamotte concrete welded to the pipes.
The main part of the pipes of the convective bundle and the right furnace screen, as well as the shielding pipes of the front wall of the furnace, are connected to the drums by rolling. To increase the strength of the rolling joints, one annular recess is rolled into the walls of the holes drilled for the pipes being rolled. When rolling, the metal of the pipe fills the recess, creating a labyrinth seal.
Pipes of the gas-tight partition are connected to the drums by electric welding or rolling: part of the pipes of the gas-tight partition, the right combustion screen and the outer layer of the convective beam, which are installed in holes located in the welds or heat-affected zone, are attached to the drum by electric welding or rolled.
The design of the rear firebox screen is possible in two versions:
1. Pipes of the rear furnace screen Ø51x2.5 mm, installed with a pitch of 75 mm, are welded to the upper and lower screen collectors Ø159x6 mm, which in turn are welded to the upper and lower drums.The ends of the rear screen collectors on the side opposite the drums are connected by an unheated recirculation pipe Ø76x3.5 mm; to protect the recirculation pipes and collectors from thermal radiation, two pipes Ø51x2.5 mm are installed at the end of the combustion chamber, connected to the drums by rolling.
2. C-shaped pipes Ø51x2.5 mm, forming the rear screen of the firebox, are installed in increments of 55 mm and connected to the drums by rolling.
Boiler superheaters 4; 6.5 and 10 t/h are made of coils from pipes Ø32x3 mm.
The superheater is a single-stage one, installed behind the first part of the convective beam at the point where the convective flue turns. Saturated steam from the upper drum is directed by one bypass pipe to the upper inlet manifold of the superheater Ø159x6 mm. The superheated steam exits from the lower collector.
On boilers of 16 and 25 t/h at a pressure of 1.4 and 2.4 MPa with steam superheating of 225°C and 250°C, the superheaters are vertical, made of two rows of pipes Ø51x2.5 mm. The outer row of pipes when entering the Ø159x6 mm collectors are cased up to Ø38 mm. The two-stage superheater is located at the beginning of the convective beam (opposite the exit window from the furnace). The outer row of the superheater, made of cased pipes, simultaneously serves as part of the enclosing wall of the boiler block. Saturated steam from the upper drum is directed by bypass pipes Ø108x4.5 mm to the upper manifold of the first superheating stage, located second along the gas flow. Having passed the pipes of the first stage, the lower manifold Ø159x6 mm and the pipes of the second stage of superheating, the steam is supplied to the outlet of the manifold Ø159x6 mm.
The steam superheater of the DE-25-24-380 GM boiler is made of coil pipes Ø38x3 mm, two-stage and is located at the beginning of the convective beam across the entire width of the flue. To regulate superheat, a surface desuperheater located in the lower drum of the boiler and two control valves are used.
Saturated steam from the upper drum is directed by bypass pipes Ø108x4.5 mm to the upper manifold of the first superheating stage (second along the gas flow). Having passed through the coils and the first stage, steam from the lower outlet of the collector is directed either by two pipes Ø108x4.5 mm to the desuperheater, or by one pipe Ø108x4.5 mm to the lower collector of the second stage of superheating (the first in the flow of gases).
Having passed the second stage, the steam is supplied to the outlet through the upper manifold. The superheater collectors are made of pipes Ø159x6 mm.
Boilers with steam capacity 4; 6.5 and 10 t/h are made with a single-stage evaporation scheme. In boilers 16; 25 t/h – two-stage evaporation scheme. The second stage of evaporation, using transverse partitions in the drums, includes the rear part of the left and right furnace screens, the rear screen and part of the convective beam located in the zone with a higher gas temperature.
The second stage of evaporation is fed from the first stage through a Ø108 mm bypass pipe passing through the transverse partition of the upper drum. The circuit of the second stage of evaporation has unheated downpipes Ø159x4.5mm.
Lowering link of circulation circuits of boilers 4; 6.5 and 10 t/h, and the first stage of evaporation of boilers 16 and 25 t/h are the last least heated rows of convective bundle pipes along the gas flow.
IN water space The upper drum contains a feed pipe and fenders, and in the steam volume there are separation devices.
The lower drum contains a device for steam heating of water during kindling, a perforated purge pipeline and pipes for draining water.
As primary separation devices, fender shields and guide visors installed in the upper drum are used, ensuring the supply of the steam-water mixture to the water level. A perforated sheet and a louvered separator are used as secondary separation devices.
The fender shields, guide visors, louvered separators and perforated sheets are made removable to allow complete inspection and repair of the rolling connections of the pipes with the drum and the drum itself. All separation devices are attached to half-clamps welded to the drum using studs and nuts. Disassembly and assembly of louvered separators and perforated sheets is carried out element by element. Dismantling of fender shields begins with the lower shield. Assembly of separation devices is carried out in the reverse order.
When assembling steam separation devices, you should pay attention to creating a tightness in the places where the fender panels are connected to each other and in the places where they are attached to the half-clamps, as well as in the places where the guide visors are connected to the strip with studs: install new paronite gaskets, lubricated with graphite.
If it is necessary to adjust the water chemistry of boilers, the introduction of phosphates should include a line between the economizer and the boiler.
On boilers with steam capacity 4; 6.5 and 10 t/h, continuous blowing is provided from the lower collector of the rear screen (in the case when the rear screen has a collector). On boilers with steam capacity 4; 6.5 and 10 t/h in which the rear furnace screen is made of C-shaped Ø51 mm, periodic boiler blowing is combined with continuous blowing, carried out from the front bottom of the lower drum: it is recommended to insert the periodic blowing pipeline in the gap between the shut-off and regulating body on the line continuous blowing.
Boilers with a steam capacity of 16 and 25 t/h have continuous blowing from the second evaporation stage (salty compartment) of the upper drum and periodic blowing from the clean and salty compartments of the lower drum and the lower collector of the rear screen (in the case where the rear screen has a collector).
Flue gas output from boilers with steam capacity 4; 6.5 and 10 t/h are carried out through a window located on the rear wall of the boiler. On boilers with a steam capacity of 16 and 25 t/h, the exit of flue gases is through a window in the left side wall of the boiler at the end (along the gas flow) of the convective beam.
For the cleaning outer surface pipes of the convective beam from deposits, the boilers are equipped with stationary blowers or a wave generator (GUV).
The blower has a pipe with nozzles that must be rotated when blowing. The outer part of the apparatus is attached to the casing of the left convective wall of the boiler. The blower pipe is rotated manually using a flywheel and chain.
For blowing, saturated or superheated steam from operating boilers is used at a pressure of at least 0.7 MPa.
The shock wave generator, like gas-pulse cleaning (GCP), is a representative of the shock wave cleaning method, based on the interaction of contaminated heating surfaces with a shock wave and a high-speed flow of combustion products that are formed during the combustion of a powder charge.
The portable device, weighing 17 kg, consists of the shock wave generator itself with a remote trigger mechanism, a corresponding barrel and a powder charge.
To carry out activities using this cleaning method, boilers are equipped with special pipes and installation platforms (attachment points to the casing).
To remove soot deposits from the convective beam, hatches are installed on the left wall of the boiler.
All boilers have three peeper hatches - two on the right side and one on the rear walls of the combustion chamber.
The opening into the firebox can be the hole of the explosion valve or the burner lance.
Explosion valves on boilers 4; 6.5; 10 t/h are located at the front of the boiler. On boilers of 16 and 25 t/h there are three explosion valves - one on the front wall and two on the boiler flue.
Boilers are manufactured at the factory in the form of one transportable unit, mounted on a support frame and including: drums, pipe system, superheater (for boilers with superheated steam), frame, insulation and casing.
Boilers can also be manufactured as a block without factory-installed insulation and cladding: in this case, the insulation and cladding of the boiler block is carried out during installation in the manner described below.
Dense shielding of the side walls (relative pitch of pipes S = 1.08), ceiling and bottom of the combustion chamber allows the use of light insulation 100 mm thick on boilers, laid on a layer of fireclay concrete 15-20 mm thick, applied over a grid. Asbestos-vermiculite slabs or those with thermophysical properties equivalent to them are used as insulation.
The lining of the front wall is made of refractory fireclay bricks of class A or B, diatomaceous brick, insulating boards, lining back wall– made of fire-resistant fireclay bricks and insulating boards.
To reduce air suction, the insulation on the outside is covered with metal sheeting 2 mm thick, which is welded to the frame.
The plant does not supply brickwork and insulation materials.
Technical documentation for insulation implementation for design organizations and customers.
Boiler blocks, in the marking of which the last letter is O, are manufactured and supplied by the plant in insulation and casing.
As insulation on these boilers, mullite-silica felt MKRV-200 GOST 23619-79 is used and mineral wool increased temperature resistance TU36.16.22-31-89, laid between dense enclosing heating surfaces and the boiler casing.
To seal inter-pipe gaps at the entrance to drums, in explosion valves, burner flanges, manhole covers and other components, asbestos cardboard KAON-1-5 GOST 2850-80 and asbestos cord SHAON 22 GOST 1779-83 are used.
Sheathing sheets for blocks supplied insulated have a thickness of 3 mm, 2 mm for boilers supplied without insulation, and are welded along the entire contour of the junction to the frame elements.
More information about the insulation (lining) of boilers is described in the sections devoted to the installation and repair of boilers.
The support frame takes the load from the boiler elements operating under boiler water pressure, as well as the frame, insulation and cladding.
The load from the boiler pressure elements and boiler water is transferred to the support frame through the lower drum.
To install the lower drum, the design of the support frame includes front and rear transverse beams with support pads, as well as supports - two to the right of the drum (from the firebox side) on the transverse beams and two to the left of the drum on the longitudinal beam.
The lower drum at the front of the boiler is fixed motionless by welding the drum to the transverse beam of the support frame through a ring and fixed supports. The frame and casing from the front of the boiler are also fixedly attached to the lower drum. Thermal expansion of the drum is provided towards the rear bottom, for which the rear supports are made movable. A benchmark is installed on the rear bottom of the lower drum to control the thermal expansion of the drum (boiler). Installation of benchmarks to control the thermal expansion of boilers in the vertical and transverse directions is not required, since the design of the boilers ensures thermal movement in these directions.
To burn fuel oil and natural gas, gas and oil burners GMP and GM are installed on the boilers (Table 1).
The main components of the burners are the gas part, a blade apparatus for swirling air, a nozzle assembly with main and backup steam-mechanical nozzles and flaps that serve to close the holes of the removed nozzle.
At the front of the burner, a peephole and an ignition-protective device are installed.
The combustion chamber for two-stage fuel combustion, installed on 25 t/h boilers, includes a housing, inner and outer shells and a tangential air swirler.
The fuel is supplied in full quantity to the GMP-16 burner, installed at the front of the combustion chamber for two-stage fuel combustion. There, through the annular slot formed by the outer casing and the inner shell of the combustion chamber, primary air is supplied (70% of the total amount of air required for complete fuel combustion), secondary air (30% of total number) enters through the annular slot and the tangential swirler of the chamber. The directions of rotation of primary and secondary air are the same.
The combustion chamber of two-stage fuel combustion is protected from torch radiation by fire-resistant fireclay masonry of class “A”.
The embrasure of the GMP-16 burner is of a conical type with an opening angle of 35° to one side, while that of the GM-10, GM-7, GM-4.5 and GM-2.5 burners is of a conical type with an opening angle of 25° to one side.
The GM-7, GM-4.5 and GM-2.5 air burners are vortex, the GM-10 burner is direct-flow vortex.
The boilers are earthquake-resistant under seismic impacts of up to 9 points (on the MSK-64 scale) inclusive.
The design of boilers is constantly being improved, so individual components and parts may differ slightly from those described in
instructions.
FITTINGS, CONTROL INSTRUMENTS AND SAFETY DEVICESDE TYPE BOILERS
Each boiler is equipped with two spring safety valves.
On boilers without a superheater, both valves are installed on the upper drum of the boiler.
On boilers with a superheater, one valve is installed on the drum, the second - on the outlet manifold of the superheater.
The valves are adjusted in accordance with the instructions in the corresponding section of the “Installation Instructions”.
The boilers are equipped with two direct-acting water level indicators, which are connected to pipes communicating with the steam volumes of the upper drum.
In boilers with a steam capacity of 16 and 2.5 t/h with a two-stage evaporation scheme, one of the water level indicators is connected to the clean compartment, the second to the salty one.
Installation of signs and their maintenance are carried out in accordance with the accompanying technical documentation of the plant and the Boiler Rules (section 6.3).
The boilers are completed required quantity pressure gauges and fittings. ..
