The need for backup or emergency fuel for a boiler house is due to the objective need to ensure uninterrupted operation of the boiler house in the event of a shutdown or non-supply of the main fuel. To fulfill this task, an irreducible supply of reserve (emergency) fuel is created at the boiler house in accordance with regulatory documents. The documents regulating the need for reserve fuel for boiler houses are:
- Rules for the technical operation of thermal power plants, approved by Order of the Ministry of Energy of the Russian Federation dated March 24, 2003 No. 115, (clause 4.1.1);
- Rules for the use of gas and the provision of gas supply services in the Russian Federation were approved by Decree of the Government of Russia of May 17, 2002 No. 137, (clause 49);
- SNiP II-35-76 “Boiler installations”, approved by Resolution of the State Committee of the USSR Council of Ministers for Construction Affairs dated December 31, 1976 No. 229, (clause 4.1);
- SP 89.13330.2012 “Boiler installations”. Updated version of SNiP II-35-76”, approved by Order of the Ministry of Regional Development of the Russian Federation dated June 30, 2012 No. 281, (clause 4.5).
The type of fuel and its classification: primary, and, if necessary, emergency, is established taking into account the category of the boiler room, based on local operating conditions, and is determined in agreement with the regional authorized authorities.
13.1 The type of fuel on which the boiler room must operate, as well as the need for an emergency type of fuel for boiler rooms are established in the design assignment, taking into account the category of the boiler room and the requirements of 4.5.
Limits on annual fuel consumption in the prescribed manner are drawn up by the customer in accordance with the calculated data of the design organization in accordance with and.
13.2 The type of fuel for lighting and “lighting” boilers with chamber combustion chambers for burning solid fuel should be provided based on the requirements of the manufacturer.
13.3 The estimated hourly fuel consumption of the boiler room is determined based on the operation of all installed working boilers at their rated thermal power, taking into account the minimum calorific value of a given type of fuel.
13.4 Daily fuel consumption should be determined:
- for steam boilers - based on their operating mode at the total design thermal power;
- for hot water boilers - based on 24 hours of their operation while covering thermal loads calculated based on the average temperature of the coldest month.
Solid fuel
13.5 The requirements of this section should be met when designing structures for unloading, receiving, storing and supplying fuel on the territory of the boiler house.
13.6 For steam boilers of the combustion device with a steam output of 2 t/h and above and hot water boilers with a heating output of 1.16 MW (1 Gcal/h) and above, operating on solid fuel, the fuel supply to the boiler room and to the boiler furnace must be mechanized, and for boiler rooms with With a total output of slag and ash from boilers in the amount of 150 kg/h or more (regardless of the productivity of the boilers), slag and ash removal must be mechanized.
13.7 When delivering fuel, wagon or truck scales should be provided on the territory of the boiler room in agreement with the fuel supply organization.
13.8 The unloading front of the unloading device and the unloading front of the fuel storage should be combined. The design of a separate unloading front at a fuel warehouse is permitted with special justification.
13.9 When an unloading device with a car dumper is used, a defrosting device should be placed on the boiler room site.
13.10 Fuel warehouses and receiving and unloading facilities are, as a rule, designed open. Closed warehouses and receiving and unloading facilities are provided for residential areas, according to the special requirements of industrial enterprises on the territory of which the boiler house is located, as well as for special justification in areas with fuel delivery during the navigation period.
13.11 Sites for fuel stacks must be organized on leveled and tightly compacted natural soil.
The use of asphalt, concrete, cobblestone or wooden base for the stack is not allowed.
13.12 The fuel storage capacity should be taken as follows:
- when delivered by rail, at least 14-day consumption;
- when delivered by road transport - at least 7-day consumption;
- for boiler houses of coal mining and coal processing enterprises when delivered by conveyors - for 2-day consumption;
- when delivered only by water transport - for the inter-navigation period;
- for boiler houses operating on peat and located at a distance of up to 15 km from peat mining and peat processing enterprises - no more than a 2-day supply.
13.13 The overall dimensions of coal stacks, regardless of its tendency to oxidize, are not limited and are determined by the capabilities of the mechanisms with which the fuel warehouse is equipped.
13.14 The dimensions of peat stacks should be no more than 125 m in length, no more than 30 m in width and no more than 7 m in height. The slope angles of the stacks must be at least 60° for sod peat, and at least 40° for milled peat.
13.15 The arrangement of peat stacks should be in pairs with gaps between the bottoms of the stacks in one pair of 5 m; between pairs of stacks - equal to the width of the stack along the base, but not less than 12 m. The gaps between the ends of the stacks from their base should be taken for sod peat 20 m, for milled peat - 45 m.
13.16 The distance from the bottom of the fuel stack to the fence should be 5 m, to the head of the nearest rail of the railway track - 2 m, to the edge of the roadway - 1.5 m.
13.17 The level of mechanization of coal warehouses should ensure their operation with a minimum number of personnel. The choice of mechanization system is determined taking into account the climatic conditions of the location of the boiler room, hourly fuel consumption, its quality and the requirements of boiler units, according to its fractional composition.
Warehouse mechanisms, except bulldozers, are backed up by one mechanism. When mechanizing a warehouse only with bulldozers, the reserve should be 50% of their estimated number.
When dispensing coal from a warehouse, the bulldozer mileage should be up to 75 m.
Peat warehouses must be equipped with continuous loading machines or grab cranes.
13.18 The hourly productivity of all mechanisms dispensing fuel from the warehouse must be no less than the productivity of each line of the main fuel supply path.
13.19 If there are bulldozers at the fuel warehouse, it is necessary to determine their location.
13.20 The estimated fuel supply capacity of the boiler room should be determined by the maximum daily fuel consumption of the boiler room (taking into account the expansion of the boiler room) and the number of hours of fuel supply operation per day.
The productivity of fuel supply to the warehouse from an unloading device or car dumper is determined by the productivity of the latter.
13.21 Fuel supply systems, as a rule, should be single-line with duplication of individual components and mechanisms.
When fuel supply operates in three shifts, a two-thread system of belt conveyors must be provided, of which one thread of conveyors is a reserve. The hourly productivity of each line should be taken equal to the calculated hourly productivity of the fuel supply. Fuel supply from the unloading device to the warehouse must be carried out via a single-thread conveyor system.
13.22 When using boilers with different fireboxes (chamber, layer, “fluidized bed” fireboxes), crushers of various fuel grinding types should be provided in the fuel supply path.
When working on fine fuel (0-25 mm), it must be possible to work in addition to crushers.
13.23 In the fuel supply path on the conveyors in front of the crushers, a device is installed to catch metal inclusions from the fuel. For dust preparation systems with medium-speed and hammer mills, this device should also be installed after the crushers.
13.24 Installation of belt scales should be provided in the main fuel supply path.
13.25 When fuel consumption is more than 50 t/h in the fuel supply path on conveyors after crushers, sampling and sample-dividing installations must be provided to determine the quality of the fuel.
13.26 With a two-line fuel supply system, cross-flows should be provided before and after the crushers.
13.27 The angle of inclination of belt conveyors when transporting fuel uphill and using smooth belts must be no more than:
- 12° - in the loading area of uncrushed lump coal;
- 15° - on uncrushed lump coal;
- 18° - on crushed coal.
13.28 Belt conveyors of the fuel supply path, as a rule, should be installed in closed heated galleries. Open installation of belt conveyors is allowed for areas with outside air temperatures for heating calculations above minus 20°C and a conveyor belt designed to operate at sub-zero temperatures.
The width of the passage between conveyors must be at least 1000 mm, and the width of the side passages - at least 700 mm. The clear height of the gallery at the passage points must be at least 2.2 m.
Local narrowing of side passages up to 600 mm is allowed.
With one conveyor, the passage must be at least 1000 mm on one side, and at least 700 mm on the other.
The distance between emergency exits should not exceed 200 m for above-ground galleries and 100 m for underground galleries.
In galleries, it is necessary to provide transition bridges over conveyors every 100 m. In these places, the height of the gallery should provide free passage.
13.29 The angle of inclination of the walls of receiving hoppers and transfer boxes is taken to be at least 60°, for high-moisture coals, sludge and middlings, at least 65°.
The walls of the bunkers of the unloading devices and the fuel storage must be heated.
13.30 Indoor fuel transfer devices, as well as raw fuel bunkers, should be designed hermetically sealed with dust suppression or collection devices.
13.31 In heated fuel supply rooms, as a rule, wet cleaning (hydraulic flushing) should be designed.
13.32 The useful capacity of the raw fuel bunker for each boiler, the operating mode of the fuel supply, as well as the feasibility of installing common fuel bunkers in the boiler room must be determined on the basis of a technical and economic comparison of the indicators of possible options, is accepted in accordance with the structural characteristics of the building and must be no less than:
- for coals - a 3-hour reserve;
- for peat - 1.5 hour supply.
13.33 The walls of solid fuel bunkers should be designed with a smooth inner surface and a shape that allows fuel to drain by gravity. The angle of inclination of receiving and transfer bins, the walls of the conical part of silos, as well as transfer hoses and chutes should be taken as follows:
- for coals with an angle of repose no more than 60° 60°
- for coals with an angle of repose of more than 60° and peat 65°
- for industrial product 70°.
The inside edges of bin corners should be rounded or chamfered. Coal and peat bunkers should be equipped with devices to prevent fuel from getting stuck.
13.34 The design of installations and dust preparation systems for boilers with chamber combustion of solid fuels should be carried out taking into account the layout of the boiler plant manufacturer according to methodological materials for the design of dust preparation systems.
Liquid fuel
13.35 The mass of liquid fuel entering the fuel storage facility must be determined by measurement. Installation of scales to determine the mass of liquid fuel is not provided.
13.36 The length of the unloading front of railway tanks with a carrying capacity of 60 tons should be taken for the main, reserve and emergency fuel oil facilities:
- for boiler houses with thermal power up to 100 MW - for two tanks (one or two rates);
- for boiler houses with a thermal capacity of more than 100 MW - based on the discharge of daily fuel oil consumption at two rates.
13.37 Drain devices for fuel oil delivered by road transport should be provided for unloading one road tank.
13.38 Light oil fuel discharge devices should be taken on the basis of unloading one railway or road tank.
13.39 To heat and drain fuel from railway tanks, as a rule, “closed” drain installations with circulating heating of fuel in railway tanks with a heated product should be used. It is also allowed to use heating of fuel oil in railway tanks with “open” steam and “open” discharge into inter-rail drain trays.
13.40 The slope of trays and pipes through which fuel is drained into a fuel storage or receiving tank must be at least 0.01.
Between the tray (pipe) of drain devices and the receiving container or in the container itself, it is necessary to install a hydraulic seal and a lifting mesh (filter) for fuel purification.
13.41 Along the entire fuel oil unloading front at the level of railway tank service areas, it is necessary to provide an overpass for servicing the heating device.
13.42 The working capacity of the receiving tank for rail fuel delivery must be at least 30% of the capacity of the tanks simultaneously installed for unloading.
The capacity of the transfer pumps of the receiving tank should be selected taking into account the pumping of discharged fuel oil from tanks installed for unloading in no more than 3 hours. At least two pumps should be installed without reserve.
13.43 For road delivery, the capacity of the receiving tank should be taken as follows:
- for emergency and main fuel in boiler houses with a thermal power of up to 25 MW, equal to the capacity of one tank truck;
- for the main fuel in boiler houses with thermal power from 25 to 100 MW, at least 25 m 3;
- thermal power above 100 MW - at least 100 m 3.
In this case, the tank for receiving fuel from tank trucks should be made of steel above ground.
13.44 For the storage of fuel oil, steel or reinforced concrete above-ground with sprinkling or underground tanks should be provided.
As a rule, steel tanks should be provided for storing light petroleum fuels and liquid additives. It is allowed to use tanks made of special plastic materials that meet the climatic conditions of the construction site and fire safety requirements, which must be confirmed by a certificate of compliance with fire safety standards.
For above-ground metal tanks installed in areas with an average annual outdoor temperature of up to +9°C, thermal insulation made of non-combustible materials must be provided.
13.45 The capacity of liquid fuel storage tanks should be taken according to table 13.1
Table 13.1
13.46 At least two tanks should be provided for storing the main fuel. One tank may be installed to store emergency fuel.
13.47 Liquid fuel supply tanks must be installed outside the boiler room.
In the premises of free-standing boiler rooms (but not above boilers or economizers), it is allowed to install closed liquid fuel supply tanks with a capacity of no more than 5 m 3 for fuel oil and 1 m 3 for light liquid fuel.
13.48 For block-modular boiler houses with a thermal power of up to 10 MW, the receiving tank and storage tank can be combined.
13.49 The heating temperature of liquid fuel in railway tanks should be taken as follows:
- fuel oil M 40 30 °C;
- fuel oil M 100 60 °C;
- for light oil fuel 10 °C.
Heating of fuel delivered by road transport is not provided.
13.50 In receiving tanks, drain trays and pipelines through which fuel oil is discharged, devices should be provided to maintain the temperatures specified in 13.61.
13.51 In places where liquid fuel is taken from fuel storage tanks, the following temperature must be maintained:
- fuel oil M 40 at least 60 °C;
- fuel oil M100 at least 80 °C;
- light oil fuel 10 °C.
13.52 The fuel oil facility must ensure a continuous supply of heated and filtered fuel oil of the required pressure to the nozzles.
13.53 Fuel oil pipelines of boiler installations (from the boiler room mains to the burners) must be made of seamless pipes by welding. Flange connections are allowed only in places where fittings, measuring devices and plugs are installed.
Only steel fittings of the 1st class of tightness according to GOST 9544 should be used on fuel oil pipelines.
13.54 To ensure explosion safety, the following must be installed:
- at the outlet of the fuel oil pipeline to the boiler plant - a shut-off (repair) device with a manual or electric drive, a shut-off device with an electric drive, a flange connection for installing a plug with a device for expanding flanges with a conductive jumper, a device for purging the fuel oil pipeline and nozzles with steam, a flow metering device for boilers with a power of more than 1 MW, a safety shut-off valve with a response speed of no more than 3 s, a control valve;
- on the outlet to the recirculation line - a flow metering device, a check valve, a device for installing a plug and a shut-off device with an electric drive (in the case of working in a dead-end circuit, the flow metering device may not be installed);
- on the outlet to the drain line (emptying) - a device for installing a plug and a locking device;
- on the fuel oil supply line to the nozzle - a shut-off device with an electric drive and a shut-off device directly at the nozzle with a manual or electric drive. On newly commissioned gas-oil boilers with a heating capacity above 100 Gcal/h, a shut-off valve and an electrically driven shut-off device must be installed in front of each burner.
13.55 On boilers that use fuel oil in an automatic device for “picking up” a pulverized coal torch, in addition to two shut-off devices, an electromagnetic valve must be installed on the bypass of the shut-off device with an electric drive on the fuel supply line to the “pick-up” nozzle of the torch.
13.56 The slam-shut valve electromagnet must be powered from a battery or from a battery of pre-charged capacitors. The control circuit of the SPD electromagnet must be equipped with a device for continuous monitoring of the circuit's health.
13.57 Steam must be supplied to the nozzles in such a way that it excludes the possibility of it entering the fuel oil path of the nozzle during its operation, as well as fuel oil entering the purge steam line and its condensate lines. The purge steam supply lines to the nozzles must be designed in such a way that they are filled with steam and not condensate.
13.58 All fuel oil pipelines must be grounded when electrified fittings are installed on them.
13.59 It is prohibited to lay fuel oil pipelines through the gas ducts of the boiler installation, air ducts and ventilation shafts.
13.60 The viscosity of the fuel oil supplied to the boiler room must be:
- when using steam-mechanical nozzles, no more than 3° HC, which for grade 100 fuel oil corresponds to approximately 120 °C;
- when using mechanical nozzles - 2.5° HC, which for grade 100 fuel oil corresponds to approximately 135 °C;
- when using steam and rotary nozzles, no more than 6° HC, which for grade 100 fuel oil corresponds to approximately 90 °C.
13.61 Heating of fuel oil in storage tanks is provided by a circulation system. When circulating heating of fuel oil, the following may be provided:
- an independent scheme that provides for the installation of special pumps and heaters;
- use of pumps and heaters for supplying fuel oil to the boiler room;
- use of pumps pumping fuel oil from a receiving tank.
The capacity of this equipment must be at least 2% of the capacity of the largest tank.
13.62 To heat fuel oil, steam with a pressure of 0.7 to 1.0 MPa or superheated water with a temperature of at least 120 °C should be used.
13.63 The supply of liquid fuel to the boiler room is provided according to a circulation circuit; it is allowed to supply light oil fuel - according to a dead-end circuit.
13.64 The number of pumps for supplying fuel from the fuel storage to the boiler room (or to the boilers) must be at least two. One of the installed pumps is a reserve one.
The performance of fuel supply pumps must be at least 110% of the maximum hourly fuel consumption when all boilers are operating in a circulation circuit and at least 100% in a dead-end circuit.
13.65 To clean fuel from mechanical impurities, coarse filters (before pumps) and fine filters (behind fuel oil heaters or before burners) should be provided. At least two filters for each purpose are installed, including one backup.
For pipeline supply, coarse filters are not provided.
13.66 In boiler houses designed to operate only on liquid fuel, the supply of fuel from fuel pumps to boilers and the supply of coolant to fuel supply units is provided for boiler houses of the first category along two lines, and for boiler houses of the second category along one line. Each line must be designed to supply 75% of the fuel consumed at maximum load. When using liquid fuel as a reserve, emergency or starting fuel, its supply to the boilers is provided through one line, regardless of the category of the boiler room.
13.67 For emergency shutdown, shut-off valves are installed on the suction and discharge fuel lines at a distance of 10 to 50 m from the pump station.
13.68 The location of liquid fuel pipelines in boiler rooms should be open, providing free access to them. It is not allowed to lay liquid fuel pipelines below the zero mark.
13.69 For light oil fuel pipelines at pressures up to 1.6 MPa, electric-welded pipes should be used; at higher pressures, seamless pipes should be used.
For liquid fuel pipelines in the boiler room, as a rule, steel fittings should be provided.
13.70 In boiler houses operating on light oil fuel, the following should be provided on the fuel lines:
- a shut-off device with an insulating flange and a quick-acting shut-off valve with an electric drive at the fuel input to the boiler room, while the quick-acting shut-off valve must shut off the fuel supply to the boiler room when the power supply is turned off, in response to a fire alarm signal and a gas contamination signal of 100 mg/m 3 of carbon monoxide;
- shut-off valves on the outlet to each boiler or burner;
- shut-off valves at the outlet to the drain line.
13.71 The use of stuffing box compensators on fuel oil pipelines is not allowed.
13.72 Boiler room fuel oil pipelines must have a heat-insulating structure made of factory-ready non-combustible materials, and when laid outdoors, a heating “satellite” in common insulation with it.
13.73 The use of a fuel oil pipeline as a structure bearing the load from any structures or devices is not permitted.
Fuel oil pipelines within the boiler room must have a slope of at least 0.003.
13.74 External laying of fuel pipelines, as a rule, should be provided above ground. Underground installation is allowed in non-passable channels with removable ceilings with minimal deepening of the channels without backfilling. Where the channels adjoin the outer wall of the building, the channels must be filled in or have fireproof diaphragms.
Fuel pipelines must be laid with a slope of at least 0.003.
All fuel oil pipelines must be provided in common insulation with coolant pipelines.
Channels for laying light oil and diesel fuel should not allow fuel to get into the ground and at their lowest points along the profile have drainage with the installation of a control, sealed for fuel, well to receive leaks.
13.75 In fuel oil facilities, as a rule, devices should be provided for receiving, draining, storing, preparing and dosing liquid additives into fuel oil.
The total capacity of tanks for storing liquid additives is assumed to be no less than the capacity of a railway (automobile) tank. The number of tanks must be at least two.
13.76 Fire-up fuel oil facilities for boiler houses burning solid fuel are provided in the following volume:
- unloading front for delivery by rail or road transport, designed for the installation of two corresponding tanks;
- fuel oil storage facility with the installation of two tanks with a capacity of 200 m 3 each;
- for supplying fuel oil to the boiler room - two sets of pumps, heaters and filters, one set as a reserve, installed in the fuel oil pumping room;
- from the fuel oil pumping station to the boiler room, one pressure fuel oil pipeline, one steam pipeline and one recirculation fuel oil pipeline are laid.
Equipment performance and pipeline capacity are selected taking into account the firing of the two largest boilers and their operation at a load of 30% of the nominal capacity.
13.77 In boiler rooms, it is allowed to provide for the installation of closed liquid fuel supply tanks with a capacity of no more than 5 m 3 for fuel oil, and 1 m 3 for light oil fuel.
When installing these tanks in boiler rooms, you should be guided by SP 4.13130.
13.78 To maintain the required pressure in the fuel oil pipelines in the boiler room, at the initial section of the recirculation line from the boiler room, it is necessary to install control valves “upstream”.
13.79 To collect drainage from the equipment and pipelines of the fuel oil pumping and boiler room, a drainage tank should be provided, located outside the fuel oil pumping and boiler room.
Gaseous fuel
13.80 Gas supply should be designed in accordance with the requirements of this section and SP 62.13330 and SP 4.13130.
13.81 If it is necessary to maintain the required gas pressure in boiler rooms, gas control units (GRU) should be provided, located directly in the boiler room, or gas control points (GRP) on the boiler room site.
13.82 The productivity for boiler houses burning gas as the main type of fuel should be calculated based on the maximum gas consumption of all working boilers; for boiler houses that burn gas seasonally - according to gas consumption for a given mode.
13.83 In the GRU (GRP), two reduction strings should be provided for each boiler with a unit thermal power of 30 MW or more. For boiler houses with a unit installed thermal power of boilers of less than 30 MW, one reduction line should be provided for every 30 MW of total installed thermal power of the boilers.
13.84 For a boiler house of the first category with a total thermal power of less than 30 MW, two reduction lines should be provided, one of which is a reserve one.
13.85 For boiler houses designed to operate only on gaseous fuel with a total installed capacity of less than 30 MW, the gas supply from the gas distribution unit (GRU) to the boilers must be provided through two pipelines for boiler houses of the first category and one pipeline for boiler houses of the second category.
13.86 It is not allowed to lay gaseous fuel pipelines below the zero mark.
13.87 The choice of fitting material for gaseous fuel pipelines in the boiler room should, as a rule, be made based on climatic conditions and gas pressure.
13.88 The use of stuffing box compensators on gas pipelines of a boiler room is not allowed.
13.89 The use of a gas pipeline as a structure bearing the load from any structures or devices is not permitted.
13.90 The gas supply pipeline to the boiler room must be provided with a disconnecting device with an insulating flange on the outer wall of the building at a height of no more than 1.8 m.
13.91 On the gas pipeline inside the boiler room the following should be provided:
- on the gas outlet to each boiler - shut-off valves, a quick-acting shut-off valve and a thermal shut-off valve, a flow metering device for boilers over 1 MW;
- on the gas outlet directly to each burner - shut-off valves, if these devices are not provided by the gas train supplied with the boiler or burner.
13.92 Gas burner devices of boilers must be equipped with shut-off and control devices in accordance with GOST 21204 and.
13.93 The selection of pipeline material, fittings and determination of their placement locations must be made in accordance with SP 62.13330.
13.94 It is prohibited to lay gas pipelines directly through gas ducts, air ducts and ventilation shafts.
13.95 It is not permitted to convert boilers to burn liquefied gas in operating boiler rooms whose floor level is below the level of the territory directly adjacent to the boiler room.
The company "Skhid-budkonstruktsiya", Kyiv, manufactures custom-made metal containers and fuel storage tanks. In Ukraine, decentralized heat supply usually uses diesel fuel and light grades of fuel oil. First of all, this is due to the convenience of their transportation and storage, low viscosity, which facilitates the task of efficient combustion, as well as low sulfur and ash content, which solves the problem of environmental pollution and equipment safety.
Abroad, boiler fuel is usually divided into distillate (furnace) and residual (fuel oil). The first is obtained by thermal and catalytic cracking of petroleum products and coking of residual fuel. About 60% of it is spent on heating buildings. In the UK, heating oil is sometimes called household oil, in France - light oil, in the USA - nozzle oil.
In Ukraine, the term “heating oil” is often used to mean diesel fuel, which is not entirely correct. In terms of fractional composition, household heating fuel (TU 38. 101656-87) may be slightly heavier than diesel produced in accordance with GOST 305-82. Comparison of the characteristics of both fuels predetermines the choice in favor of diesel fuel, but both are used in heat supply.
GOST 305-82 establishes three types of diesel fuel; summer (L), winter (W) and arctic (A). Based on sulfur content, diesel fuel is divided into fuel with a sulfur content (by weight) of no more than 0.2 and no more than 0.5%.
Information about the type of diesel fuel and the amount of sulfur in it is indicated in the designation of the fuel brand. For summer fuel, the marking also indicates the flash point, and for winter fuel, the pour point. For example, the code L-0.2-40 indicates summer fuel with a sulfur amount of up to 0.2% and a flash point of 40 (degrees C). Code 3-0.2-35 indicates that we are dealing with winter diesel fuel; it contains up to 0.2% sulfur; the pour point is -35 (degrees C). Diesel fuel of grade A-0.4 is arctic (can be used at temperatures down to -50 (degrees C); the sulfur content in it is 0.4%. The main feature of all brands of diesel fuel is low viscosity: even with summer grades, the kinematic viscosity at 20 (degrees C) leaves 3-6 cSt.
The quality of boiler fuel abroad and in Ukraine is assessed using the same physical and chemical indicators. Only the methods for determining some constants and their evaluation differ. An analogue of one or another domestic fuel should be selected primarily based on its relative viscosity.
In recent years, the market for liquid fuels with low (no more than 0.005% by weight) sulfur content has been growing in Western countries. This fuel is more expensive, but is characterized by more complete and cleaner combustion. In addition, it facilitates the use of condensing boilers (in particular, there is no need to neutralize the condensate). The result is fuel savings, reduced equipment maintenance costs and a reduction in harmful emissions into the atmosphere. In 2006, the Parliament of the Federal Republic of Germany decided to speed up, from January 1, 2009, the transition in heat supply to fuel with low sulfur content. In addition, from January 1 of this year, the sulfur content standard in conventional EL fuel has been halved (corresponding amendments have been made to DIN-51603). Now it is 0.1% (previously 0.2).
Another global trend is the development of biofuels.
Fuel delivery to heat supply facilities is carried out by specialized enterprises. When choosing a supplier, the customer should give preference to proven companies that have been operating in the market for these services for a long time. The quality of the fuel must be confirmed by a passport and meet the requirements set by burner manufacturers.
The use of insufficiently high-quality fuel results in an increase in the cost of servicing the system - more often there is a need to replace injectors, a fuel filter, clean sediment from fuel tanks, and reconfigure the burner.
Fuel storage in boiler tanks
Liquid fuel is an environmentally hazardous and flammable material. Requirements for the placement and design of installations operating on it are determined by considerations of protection from natural water pollution and fire safety.
The required supply of liquid fuel is stored in special tanks - steel tanks and tanks. Previously, reinforced concrete tanks for underground installation were also produced abroad. Currently, they are no longer produced from them, although they are in operation.
As a rule, horizontal metal containers have a volume from 2.5 m3 to 75 m3 and can be combined into batteries using special fixing packages. Single and double-walled models are common.
Single-wall tanks are designed for above-ground installation and must be located in such a way that, in the event of a leak, the fuel is held in place until it is removed - in rooms with a sealed floor and lower part of the walls or in sealed trays. (The collection volume is calculated for all the fuel contained in the tank, and if there are several non-communicating tanks, for the capacity of the largest tank.) This requirement is not imposed on a storage facility with double-walled tanks. They are equipped with devices for monitoring fuel leakage into the space between the inner and outer shells.
According to leading Western manufacturers, it is double-walled containers that meet modern environmental standards. In Germany, for example, the installation of a double-walled tank with a leak-monitoring system is now required in all cases where the storage volume exceeds 1000 liters. This is also mandatory if the tank is located underground.
In general, the approach to organizing reservoir management has changed noticeably in European countries recently. Manufacturers are offering the market increasingly reliable, compact tank models that can be flexibly combined into ergonomic batteries.
Of course, the reality is far from the widespread use of the “Eurotank”. But in any case, the fuel storage tank must be durable (especially when installed underground), resistant to chemical, temperature and other possible influences (for example, ultraviolet rays), equipped with all the necessary piping elements.
All liquid fuel tanks must comply with current standards and quality requirements. After completing installation of the system, a specialized organization must test it and issue an acceptance certificate. In the future, the containers will need periodic inspections.
In foreign practice, when choosing a location for installing a fuel tank in an individual and small-family home, preference is often given to the basement. According to German regulations, when installed above ground, tanks must not be placed above combustion devices, chimneys, chimneys, chimneys, chimneys, or warm air ducts.
It is also prohibited to install tanks in passages and passages, on staircases (except for residential buildings with no more than two apartments), in accessible lobbies, on the roofs of residential buildings, hospitals, office and other similar buildings, as well as in their attics and work areas (possible - in special cabinets and in a volume of up to 5000 liters).
According to SNiP II-35-76* “Boiler installations”, it is not allowed to use liquid fuel for roof-top boiler houses. Boilers operating on liquid fuel with a flash point below 45* C are also prohibited from being placed in basements.
If the boiler room is located in a separate building, diesel fuel storage tanks can be placed in a room attached to it. In this case, the total capacity of the tank should be no more than 150 m3 for fuel oil and 50 m3 for light oil fuel. In the boiler room itself (but not above boilers or economizers), it is allowed to install a closed supply tank for liquid fuel with a capacity of no more than 5 m3 for fuel oil and 1 m3 for light oil fuel.
For built-in and attached autonomous boiler houses, closed liquid fuel storage facilities should be provided, located outside the boiler room and the building for which it is intended. The capacity of supply tanks installed directly in the boiler room should not exceed 800 liters; they should be placed in sealed trays, at a distance of at least 1 m from the firebox.
The fuel tank equipment includes a number of elements. The caps of the receiving neck of the tank can be of a pouring design. One of the simplest can be considered a lid equipped with a mount for a padlock. A more complex lid - a universal one - is sealed, requires the attachment of a measuring ruler to it and is quite suitable for filling the container using the so-called gas pendulum method. There are also covers with a breathing valve and ball valves with a remote spiral or a special “foot”. To prevent contact corrosion, the spiral is made of spring steel, and the valve ball is made of stainless steel.
The standard valve assembly for fuel extraction is equipped with check ball valves on the supply and return pipelines. It may have an adjustable level limiter, as well as (in single-pipe systems) a float, which ensures the intake of clean fuel from a depth of 4-6 cm below its level.
In addition, the containers include fuel level indicators and limiters with warning devices. They can be mechanical (adjustable for container height - 0-2 m), pneumatic (1-3 m) or another design.
A tank leakage sensor is installed on the suction and measuring pipelines, in some versions it is combined on the container neck cover.
E.A. Karyakin, Development Director, Gazovik Group of Companies, Saratov
Features of using LPG
In many developed countries (USA, Canada, etc.), the use of liquefied hydrocarbon gases (LPG) as a source of backup power for boiler houses operating on natural gas is a standard solution. Despite the obvious advantages over traditional alternative backup power sources (diesel fuel, heating oil, coal), it is, nevertheless, not widespread enough in Russia.
LPG is cheaper than fuel oil and diesel fuel, and is much more environmentally friendly. The LPG storage park does not need to be heated in winter, which reduces operating costs. When using a mixing system (for more details about the system, see below. - Editor's note), the transition from natural gas to a mixture of air with the vapor phase of LPG is carried out almost instantly and unnoticed by the consumer.
Why is such a solution unclaimed in Russia? One of the reasons is the lack of practice in using mixing systems in Soviet times. In theory, they are known quite well; a description of the principles of their operation is in many Soviet and Russian textbooks on gas and heat supply. But since we almost never produced such equipment, the experience of using it is extremely limited.
Currently, the situation has begun to change. Thus, in recent years, more than 20 large facilities using LPG as a backup fuel have been designed, built and put into operation by our company’s specialists.
The economics of costs for the construction and operation of backup power systems allows us to talk about good prospects for the use of LPG in Russia. And here we cannot ignore the current regulatory framework.
Reserve fuel for boiler houses is intended for use when the supply of natural network gas is limited or stopped for a long period of time (within the framework of the “Gas Supply Rules in the Russian Federation”), which is associated with seasonal unevenness in gas consumption during peak loads.
According to paragraphs. 4.1, types of main, reserve and emergency fuel, as well as the need for reserve or emergency fuel for boiler houses are established taking into account the category of the boiler house, based on local operating conditions and in agreement with fuel supply organizations.
In practice, fuel reservation is used in boiler houses of socially significant facilities with special requirements of sanitary rules and regulations for central heating and hot water supply systems (primarily hospitals, schools, preschool institutions, etc.).
The most widely used reserve fuels are liquid hydrocarbons (diesel fuel, fuel oil), liquefied hydrocarbon gases (LPG), and, less commonly, solid fuels (coal, peat, firewood). Below we propose to consider the concept of using liquefied hydrocarbon gases (usually a propane-butane mixture in various proportions) in comparison with the most commonly used diesel fuel.
In boiler rooms with a relatively small supply of diesel fuel, the tank is mounted in an additional auxiliary compartment, hermetically separated from the main one. In boiler houses of greater power and/or with a large emergency reserve, fuel storage is arranged in special above-ground or underground tanks (Fig. 1). In this case, fuel is supplied to the burners using pumps. When the tanks are located on the ground, it is also possible to have heating elements for heating diesel fuel during the cold period.
Rice. 1. Diagram of a boiler room with backup diesel fuel.
In boiler systems using LPG, fuel storage tanks are located below ground level (Fig. 2). The main elements of the equipment of such a boiler house are also the technological piping of the tanks, a pumping group, evaporation and mixing systems, often combined into one unit. The steam phase is supplied to the boiler room burners through thermally insulated pipelines.
Rice. 2. Diagram of a boiler room with an LPG fuel reserve.
The most effective way to use LPG as a reserve fuel is to mix it with air to achieve the calorific value of natural gas. In English-language literature, such a mixture of LPG and air is called SNG (short for synthetic natural gas - synthetic natural gas - Ed.). At the same time, at the moment the automation switches from natural gas to SNG, the boiler room equipment “does not notice” such a change, because both types of fuel are almost identical.
Rice. 3. Installation for the production of SNG Metan in the warehouse of the plant.
In Fig. Figure 3 shows a mixing plant for producing SNG.
Among the projects being implemented using the mixing system of the reserve fuel economy is the reconstruction of the heat supply system of the village. Nesvetay-GRES and four microdistricts of Krasny Sulin, Rostov region. In the new block-modular boiler house with a capacity of 19.3 MW, the boilers are equipped with burners that do not allow the use of liquid fuel, so it was not possible to use diesel or fuel oil as a backup. As a result, a backup fuel system (RFF) based on LPG was designed for it. At the first stage, the operation of the boiler house using natural gas from the network gas pipeline was ensured, and at the second stage, the commissioning of the RTX was ensured (the work is at the final stage). The equipment included in the RTX is located on an area adjacent to the main land plot and is an LPG storage tank farm with a volume of 225 m3 with the installation of a mixing system with a capacity of 708 m3/h for propane (Fig. 4-6).
Rice. 4. Construction of a backup power system for a boiler house in the city of Krasny Sulin, Rostov region.
Rice. 5. Piping of LPG tanks
Rice. 6. Pumping unit for pumping the liquid phase of LPG.
A gas-air mixture (56% LPG + 44% air) is used as a reserve (emergency) fuel. The percentage ratio of LPG/air is adopted in such a way as to ensure proper combustion of the gas-air mixture in natural gas burners without any reconfiguration.
According to the technological scheme, the following operations are performed on the territory of the RTH:
■ reception of LPG delivered in automobile tanks and discharge into underground tanks;
■ storage of liquefied gas;
■ supply of LPG to the evaporation plant;
■ evaporation of the liquid phase of LPG;
■ reduction of the vapor phase of LPG;
■ mixing the LPG vapor phase with air;
■ supplying the mixture to the receiver;
■ supply of the mixture from the receiver to the boiler room.
The cost of implementing the RTX project amounted to about 40 million rubles. The cost of LPG filled into tanks is about 2.5 million rubles. This volume of reserve fuel is sufficient for 3 days of autonomous operation of the boiler room at maximum power.
Comparison with diesel boiler room
Let's consider diesel fuel and LPG from the point of view of the volume and cost of daily consumption at maximum boiler load per 1 MW, conditionally assuming equal boiler efficiency, the cost of equipment, installation and operation of boiler houses of the same capacity with backup fuel in the form of diesel fuel and LPG. As LPG we will consider a propane-butane mixture of the PBT brand with a propane content of no more than 60% according to GOST R 52087-2003.
Daily fuel consumption is calculated using the following formula:
Vts = (P n.*24)/(efficiency to *Q in), where Vts. - daily volume of fuel consumption; R n - rated power of the boiler room, kW; Efficiency k is the efficiency of boilers; Q in - specific heat of combustion of fuel per calculation unit.
With a boiler house power of 1 MW, efficiency k = 0.95, specific heat of combustion of diesel fuel - 11.9 kWh/kg (42.8 MJ/kg; density - 0.85 kg/l), specific heat of combustion of the LPG mixture - 12, 5 kWh/kg (45 MJ/kg) (density coefficient of PBT LPG is 1.76 kg/l at a temperature of 0 °C) we obtain the results shown in the table.
Table. Cost of daily fuel consumption of a boiler house per 1 MW of power.
The table shows that, with all other parameters being equal, heating a boiler room with liquefied hydrocarbon gases is almost 2 times cheaper than with diesel fuel. And, of course, the positive effect of using LPG increases over the period in direct proportion to the volume of use of reserve fuel. At the same time, we do not consider the cost of heating containers with diesel fuel in winter, which can also be a serious cost item. According to the practice that has developed in the regions, heating of containers in the cold season is often not carried out at all, which makes it virtually impossible to start a backup power system.
In addition, compared to diesel fuel, LPG has a number of other advantages:
■ the liquid phase of LPG, having the same basic physical properties of a liquid as diesel fuel, is nevertheless not subject to a significant increase in viscosity at low temperatures (which negatively affects the transportation of diesel fuel from external storage to the burners);
■ provides, as already mentioned above, the possibility of automatic transition from the main fuel to the reserve one;
■ there is no need to use more expensive combined burners in boilers to be able to burn both gaseous and liquid fuels;
■ the cost of building a module is reduced due to the absence of an auxiliary room (which is sometimes necessary when diesel fuel storage tanks are located inside the boiler room).
We should also not forget about the environment. Combustion of diesel fuel entails disproportionately greater emissions of soot, sulfur oxides and nitrogen oxides than combustion of SNG.
It is also necessary to take into account, unfortunately, the situation with fuel theft that is typical for Russia. Diesel fuel is written off and sold, and the proceeds are appropriated. It is much more difficult to steal and sell LPG on the black market.
No less important is the aspect related to the possibility of more rational management of network natural gas consumption limits. LPG allows for more flexible use of the so-called “gas consumption armor” during the heating period, i.e. the minimum volume of gas consumption required for trouble-free operation of process equipment, subject to maximum use of reserve fuels.
We see the most promising use of LPG as a reserve in the following cases:
■ when modernizing existing boiler houses of public utility facilities to create a reserve or emergency fuel supply;
■ during the construction of new facilities under conditions of limited limits on natural gas, as well as with a guaranteed prospect of growth in heat and hot water consumption in the future.
The steady increase in prices for liquid hydrocarbons in the domestic market, their dependence on the situation on world trading floors, as well as the double growth of the domestic consumption market projected by 2020 compared to today, make the concept of using LPG as a reserve fuel the most promising.
Requirements for equipment of boiler houses using LPG
In accordance with regulatory documents, when modernizing existing boiler houses and constructing new ones, the following points should be taken into account:
■ seamless steel pipes should be used for the liquid phase of LPG, steel seamless or electric-welded pipes for the vapor phase of LPG, and for gas pipelines of the vapor phase of low-pressure LPG from tank installations, the use of polyethylene and multilayer polymer pipes is allowed. The material of pipes, pipeline shut-off valves, connecting parts is selected taking into account gas pressure, the design temperature of the outside air in the construction area and the temperature of the pipe wall during operation, soil and natural conditions, the presence of vibration loads, etc.;
■ the design of the shut-off valves must ensure resistance to the transported medium and test pressure. Shut-off and control valves must ensure the tightness of the valves is not lower than class “B”.
The design of automatic fast-acting safety shut-off valves in front of burners and safety shut-off valves on gas pipelines of the liquid phase of LPG must ensure the tightness of the valves is not lower than class “A”. The tightness classes of the valves must be determined according to GOST 9544;
■ the ventilation system must provide 10-fold air exchange during working hours, with 2/3 of the air intake volume must be provided from the lower zone of the room and 1/3 from the upper zone. If there is insufficient air exchange, working with liquefied hydrocarbon gases is not allowed. Electric motors of exhaust fans must be explosion-proof;
■ Before filling, tanks must be checked for excess pressure, which must be at least 0.05 MPa (except for new tanks and after technical examination, diagnosis and repair). Tanks should be filled with the liquid phase of LPG to no more than 85% of their geometric volume.
Literature
1. . M.: Ministry of Regional Development of Russia, 2012.
2. GOST R 52087-2003. Hydrocarbon liquefied fuel gases. Technical conditions. Enter. 06/30/2003. - M.: Gosstandart of Russia, 2003.
3. : with change. from 07.12.05 and 10.05.10. - M., 2010.
4. SP 62.13330.2011 Gas distribution systems. Updated edition of SNiP 42-01-2002 (with amendment No. 1). Order of the Ministry of Regional Development of Russia dated December 27, 2010 No. 780. - M.: Ministry of Regional Development of Russia, 2011.
5. GOST 9544-2005. Pipeline shut-off valves. Classes and standards of tightness of valves. Enter. 04/01/2008. - M.: Standartinform, 2008.
6. Federal norms and rules in the field of industrial safety “Safety rules for facilities using liquefied hydrocarbon gases.” Order of the Federal Service for Environmental, Technological and Nuclear Supervision of November 21, 2013 No. 558.
7. Industrial gas equipment: reference book, 6th ed., revised. and additional, ed. Karyakina E.A. - Saratov: Gazovik, 2013.
8. Karyakin E.A., Gordeeva R.P. Equipment for LPG // Gas of Russia. 2013, no. 1. pp. 58-64.
9. Zubkov S.V., Karyakin E.A., Polyakov A.S. Gas supply without interruption//Gas of Russia. 2014, no. 1. pp. 68-75.
11. UNLOADING, RECEIVING, STORING AND SUPPLYING FUEL TO THE BOILER ROOM
Solid fuel
11.1. The requirements set out in this section should be met when designing structures for unloading, receiving, storing and supplying fuel to the boiler room at a fuel consumption of up to 150 t/h.
When fuel consumption is more than 150 t/h, the design must be carried out in accordance with the requirements of the Standards for the technological design of thermal power plants and heating networks approved by the USSR Ministry of Energy.
When designing solid fuel warehouses, one should also take into account the requirements of the Standard Instructions for the storage of coal fuel at power plants, industrial and transport enterprises, approved by the USSR State Planning Committee and the USSR State Supply Committee.
11.2. When delivering fuel by rail at the boiler room site, carriage scales should be provided only if they are not available at the railway station or at the enterprise site where the boiler room is located.
11.3. When delivering fuel by road transport at the boiler room site, truck scales should be provided only if they are not available at the base (central) warehouse.
11.4. The unloading front of the unloading device and the unloading front of the fuel storage should be combined. The design of a separate unloading front at a fuel warehouse is permitted with special justification.
11.5. Reception and unloading devices must include devices for mechanized unloading of fuel, as well as mechanized cleaning of cars from fuel residues.
11.6. Solid fuel warehouses and receiving and unloading facilities, as a rule, should be designed open.
The design of closed fuel warehouses and receiving and unloading devices is allowed for residential areas, under cramped conditions of the boiler room site, according to the special requirements of industrial enterprises caused by the peculiarities of production technology, when burning fuel unsuitable for open storage.
11.7. Covering areas for open fuel storage should be provided in accordance with building codes and rules for the design of thermal power plants.
The use of asphalt, concrete, and wooden flooring to cover areas for open fuel storage is not permitted.
11.8. The capacity of fuel storages should be taken as follows:
- when delivering fuel by road - no more than 7-day consumption;
- when delivering fuel by rail - no more than 14-day consumption.
The fuel storage capacity of boiler houses of coal mining and coal processing enterprises, provided that coal is supplied by conveyor transport, should be no more than 2-day consumption.
When fuel is delivered only during navigation by water transport, the amount of fuel stock in warehouses is established by planning authorities.
11.9. For boiler houses located at a distance of up to 15 km from peat mining and peat processing enterprises, fuel warehouses are not provided.
11.10. The machinery and equipment provided for storage operations must not crush fuel intended for layer combustion.
11.11. The height of stacks in warehouses for coals of group I is not limited; for coals of group II the height of stacks should not exceed 12 m, for coals of group III - 6 m, for coals of group IV - 5 m.
Coal groups, as well as the length and width of the stacks, are established in accordance with the Standard Instructions for the storage of coal fuel at power plants, industrial and transport enterprises, approved by the USSR State Planning Committee and the USSR State Supply Committee.
11.12. The distances between adjacent coal stacks should be 1 m for stack heights of no more than 3 m and 2 m for higher stack heights.
11.13. The dimensions of peat stacks should be no more than 125 m in length, no more than 30 m in width and no more than 7 m in height; The slope angles of the stacks must be provided for sod peat - at least 60°, for milled peat - at least 40°.
11.14. The arrangement of peat stacks should be in pairs with gaps between the bottoms of the stacks in one pair of 5 m; between pairs of stacks - equal to the width of the stack along the base, but not less than 12 m. The gaps between the ends of the stacks from their base should be taken for sod peat 20 m, for milled peat - 45 m.
11.15. The distance from the bottom of the fuel stack to the fence should be 5 m, to the head of the nearest railway rail - 2 m and to the edge of the roadway - 1.5 m.
11.16. The estimated hourly fuel supply capacity of the boiler house is determined based on the maximum daily fuel consumption of the boiler house (taking into account the prospect of expansion of the boiler house) and the number of hours of fuel supply operation per day.
11.17. The fuel supply design should generally include the installation of a coal and milled peat crusher. When operating on fine fuel (0-25 mm), crushers should not be provided.
11.18. Before hammer and roller-gear crushers, devices for screening out fine fuel fractions and electromagnetic separators should be provided.
In dust preparation systems with medium-speed and hammer mills, magnetic separators should also be provided after the crushers.
11.19. For boiler houses designed to operate on milled peat, stumps and snags should be removed after the fuel receiving device.
11.20. The capacity of the fuel bunkers of the boilers and the corresponding operating mode of the fuel supply, as well as the feasibility of installing common fuel bunkers in the boiler room, are determined based on a comparison of the technical and economic indicators of possible options. The supply of coal in the bunkers of each boiler is taken for at least 3 hours of its operation, the supply of milled peat is for at least 1.5 hours.
11.21. Fuel supply systems, as a rule, are single-line; duplication of individual components and mechanisms is allowed. When the fuel supply operates in three shifts, a two-line system is provided, and the hourly productivity of each line is assumed to be equal to the calculated hourly fuel supply productivity.
11.22. Transfer sleeves and chutes should have a round cross-section, without fractures or bends.
11.23. For areas with a design temperature for heating design of minus 20°C and below, the installation of belt conveyors should be provided in closed galleries. The clear vertical height of the gallery is taken to be at least 2.2 m. The width of the gallery is selected based on the design of the middle longitudinal passage between conveyors with a width of at least 1000 mm and side (repair) passages along conveyors with a width of at least 700 mm.
With one conveyor in the gallery, the passages must be at least 700 mm wide.
Local narrowings (at a length of no more than 1500 mm) of the main passages up to 600 mm, side passages - up to 350 mm are allowed; At the same time, conveyors must have fences in the indicated places.
In galleries, it is necessary to provide transition bridges over conveyors every 100 m.
11.24. For areas with a design temperature for heating design above minus 20°C, it is allowed to provide for open installation of belt conveyors with dust-preventing fencing.
In this case, conveyor belts must be used that are designed for operation at the appropriate minimum outdoor temperatures.
11.25. Bunkers for solid fuel should be designed with a smooth inner surface and a shape that allows fuel to drain by gravity. The angle of inclination of the walls of receiving and transfer bunkers for coal should be at least 55°, and for peat and smearable coal - at least 60°.
The angle of inclination of the walls of boiler bunkers, the conical part of silos, as well as transfer hoses and chutes for coal should be at least 60°, and for peat - at least 65°.
The inside edges of bin corners should be rounded or chamfered. Coal and peat bunkers should be equipped with devices to prevent fuel from getting stuck.
11.26. The angle of inclination of belt conveyors for transporting coal is assumed to be no more than 18°, for peat - no more than 20°.
11.27. When designing dust preparation installations for boiler houses with chamber combustion of solid fuels, one should be guided by methodological materials on the design of dust preparation installations for boiler units of thermal power plants.
The dust preparation project must be agreed upon with the boiler manufacturer.
Liquid fuel
11.28. The mass of fuel entering the fuel storage facility is determined by measurement. Installation of scales to determine fuel mass is not provided.
11.29. The length of the discharge front of fuel oil used as emergency or starting fuel is calculated from the conditions:
- for one railway tank - for boiler houses with a capacity of up to 100 Gcal/h;
- for two railway tanks - for boiler houses with a capacity of more than 100 Gcal/h.
11.30. Drainage devices for fuel oil delivered by road transport should be provided for unloading one road tank.
11.31. Light oil fuel discharge devices must be designed to accommodate one railway or road tank.
11.32. Along the entire length of the fuel oil unloading front, at the level of the top of railway tanks, overpasses should be provided for servicing the heating device.
11.33. To drain fuel from railway tanks, receiving trays should be provided, located between the rails. Concrete blind areas with a slope of at least 0.05 towards the trays are provided on both sides of the receiving trays.
When delivering fuel by motor transport, it should be drained into a receiving container or directly into a fuel storage facility via receiving trays or through funnels.
11.34. The slope of trays and pipes through which fuel is drained into a fuel storage or receiving tank must be at least 0.01.
Between the tray (pipe) of drain devices and the receiving container or in the container itself, it is necessary to install a hydraulic seal and a lifting mesh for fuel cleaning.
11.35. The capacity of the receiving tank for fuel delivered by rail must ensure that in the event of an emergency stop of the transfer pumps, fuel can be received within 30 minutes. The tank capacity is calculated based on the standard drainage time in the summer.
11.36. To pump fuel from the receiving tank to the fuel storage facility, at least two pumps (both working) must be provided. The pump capacity is selected based on the amount of fuel drained into one unit and the standard drain time.
11.37. For fuel oil storage, reinforced concrete tanks (underground and above-ground with coating) should be provided. The use of steel tanks for storing fuel oil is permitted only with the permission of the USSR State Construction Committee. Steel tanks should be provided for storing light fuel oil and liquid additives.
For above-ground metal tanks installed in areas with an average annual outdoor temperature of up to 9°C, thermal insulation made of non-combustible materials must be provided.
11.38. The capacity of liquid fuel storage facilities depending on daily consumption should be taken according to the table.
|
Purpose and method of fuel delivery |
Liquid fuel storage capacity |
|
1. Main and reserve, delivered by rail |
For 10-day consumption |
|
2. The same, delivered by road transport |
For 5-day consumption |
|
3. Emergency for boiler houses operating on gas, delivered by rail or road transport |
For 3-day consumption |
|
4. Main, backup and emergency, delivered through pipelines |
For 2-day consumption |
|
5. Kindling for boiler houses with a capacity of 100 Gcal/h and less |
Two tanks of 100 t each |
|
6. The same for boiler houses with a capacity of more than 100 Gcal/h |
Two tanks of 200 t each |
|
Note. Reserve is a liquid fuel intended for combustion over a long period along with gas during interruptions in its supply. |
|
11.39. At least two tanks must be provided for storing main and reserve fuel. One tank may be installed to store emergency fuel.
The total capacity of tanks for storing liquid additives is determined by the conditions of their delivery (the capacity of railway or road tanks), but must be at least 0.5% of the capacity of the fuel oil storage facility. The number of tanks is accepted to be at least two.
(K) For built-in and attached individual liquid fuel boiler houses, a fuel warehouse should be provided, located outside the boiler room and heated buildings, with a capacity calculated based on storage conditions of at least 5 daily fuel consumption determined for the mode corresponding to the heat load of the boiler room in the coldest mode month, the number of tanks is not limited.
11.40. The heating temperature of liquid fuel in railway tanks should be 40-30°C for fuel oil, 100-60°C for fuel oil, and 10°C for light fuel oil. Heating of fuel delivered in automobile tanks is not provided. In receiving containers, trays and pipes through which fuel oil is discharged, devices should be provided to maintain the specified temperatures.
11.41. In places where liquid fuel is taken from fuel storage tanks, the temperature of grade 40 fuel oil must be maintained at least 60°C, grade 100 fuel oil - at least 80°C, light oil fuel - at least 10°C.
11.42. To heat fuel in railway tanks, steam at a pressure of 6-10 kgf/cm 2 should be used. To heat fuel oil in heaters, fuel storage tanks, receiving tanks and drain trays, steam with a pressure of 6-10 kgf/cm2 or high-temperature water with a temperature of at least 120°C can be used.
(K) For liquid fuel in built-in and attached boiler houses, if it is necessary to heat it in external containers, the coolant of the same boiler houses is used.
11.43. To maintain the temperature of fuel oil in fuel storage tanks, in accordance with clause 11.41 of this section, a circulation heating system should be used.
When circulating heating of fuel oil, an independent scheme can be used, which provides for the installation of special pumps and heaters, or heaters and pumps for supplying fuel oil to the boiler room can be used.
The choice of the method of circulation heating of fuel oil is made based on a comparison of the technical and economic indicators of the options.
Coil heaters are installed in tanks only at the location where fuel oil is collected.
11.44. The fuel supply to the tanks should be adjusted to the fuel level.
11.45. To heat fuel oil to the temperature required by combustion conditions in boiler furnaces, at least two heaters should be provided, including one backup.
11.46. The supply of fuel oil to boiler houses should be provided according to a circulation circuit, light oil fuel - according to a dead-end circuit.
11.47.(K) The number of pumps for supplying fuel to boilers must be at least three for boiler houses of the first category, including one reserve, for boiler houses of the second category - at least two, without a reserve.
11.48. To clean fuel from mechanical impurities, coarse filters (before pumps) and fine filters (behind fuel oil heaters) should be provided. At least two filters for each purpose are installed, including one backup.
For pipeline fuel supply, coarse filters are not provided.
11.49. (K) In boiler rooms (but not above boilers or economizers) of free-standing boiler rooms, it is allowed to provide for the installation of closed liquid fuel supply tanks with a capacity of no more than 5 m 3 for fuel oil and 1 m 3 for light oil fuel. For built-in and attached individual boiler rooms, the total capacity of the supply tanks installed in the boiler room should not exceed 0.8 m3.
When installing these tanks in boiler rooms, one should be guided by building codes and rules for the design of oil and petroleum products warehouses.
11.50. The heating temperature of fuel oil in supply tanks installed in the boiler room should not exceed 90°C.
Heating light petroleum fuel in supply tanks is not permitted.
11.51. It is allowed to provide for the installation of fuel tanks in rooms attached to boiler buildings. In this case, the total capacity of fuel tanks should be no more than 150 m 3 for fuel oil and 50 m 3 for light oil fuel.
In these cases, the installation of fuel supply pumps to burners and fuel heaters should be provided in the boiler room.
11.52. In boiler houses designed to operate only on liquid fuel, the fuel supply from fuel pumps to boilers must be provided through two lines for boiler houses of the first category and one line for boiler houses of the second category.
In cases where liquid fuel is used as a reserve, emergency or kindling fuel, its supply to the boilers is provided through single pipelines, regardless of the category of the boiler room.
The supply of coolant to the boiler house fuel supply installations is provided through one or two pipelines in accordance with the number of fuel supply lines to the boilers.
When supplying fuel and coolant through two lines, each line is designed to pass 75% of the fuel and coolant consumed at maximum load of working boilers.
(K) For boiler houses operating on light oil fuel, the following should be provided on the fuel lines:
- shut-off device with an insulating flange and a quick-acting shut-off valve with an electric drive at the fuel input into the boiler room;
- shut-off valves on the outlet to each boiler or burner;
- shut-off valves at the outlet to the drain line.
11.53. The laying of fuel lines should be above ground. Underground installation in non-passable channels with removable ceilings with minimal deepening of the channels without backfilling is allowed. Where channels adjoin the outer wall of buildings, the channels must be filled with sand or have fireproof diaphragms.
(K) Fuel lines must be laid with a slope of at least 0.003. It is prohibited to lay fuel lines directly through exhaust gases, air ducts and ventilation shafts.
Gaseous fuel
11.54. Gas equipment for boiler houses should be designed in accordance with building codes and rules for the design of internal and external gas supply devices and Safety Rules in the gas industry, approved by the USSR State Technical Supervision Authority, taking into account the instructions of this section.
11.55. To maintain the required gas pressure in front of the boilers, gas control units (GRU) should be provided, located directly in the boiler rooms. The installation of gas control points (GRP) is allowed.
11.56. The choice of main equipment for gas distribution and hydraulic fracturing should be made based on the calculated gas flow rate at the maximum productivity of the installed boilers (without taking into account the productivity of backup boilers).
When choosing a pressure regulator, gas flow should be taken with a safety factor of 1.15 to the design flow.
11.57. For boiler houses intended to operate only on gaseous fuel, the gas supply from the gas distribution unit (GRU) to the boilers must be provided through two pipelines for boiler houses of the first category and one pipeline for boiler houses of the second category.
In cases where it is possible to operate boiler houses using two types of fuel, gas is supplied through one pipeline, regardless of the category of the boiler house.
11.58. In boiler houses with a capacity of more than 150 Gcal/h, two reduction lines should be provided in the gas distribution unit (GRP).
In the remaining boiler houses in the gas distribution unit (GRU), one reduction line and a bypass line should be provided.
11.59. (K) For built-in, attached and roof-top boiler rooms, a natural gas supply with a pressure of up to 5 kPa should be provided. In this case, open sections of the gas pipeline must be laid along the outer wall of the building along a partition at least 1.5 m wide.
11.60. (K) The following must be installed on the gas supply pipeline to the boiler room:
- a disconnecting device with an insulating flange on the outer wall of the building at a height of no more than 1.8 m;
- quick-acting shut-off valve with electric drive inside the boiler room;
- shut-off valves on the outlet to each boiler or gas burner device.