The main task of a solid fuel boiler house or a fluidized-bed thermal power plant is the utilization of solid fuel (SRF) processed from waste and the generation of heat and electricity. SRF fuel is preliminary produced at the Tyrannosaurus automated waste processing line.
A boiler room or thermal power plant is designed in accordance with EU standards regarding emissions of harmful impurities into the atmosphere: Directives 2000/76 / EC. It is supposed to work for 24 hours a day, 7 days a week. Based on the average monthly operating mode and the basic calculation data, the load factor, which should be taken as the base, will be 70-100% of the estimated performance.
Based on our experience, we expect reliable operation for more than 8000 hours per year.
Subject to all service intervals, fuel and service requirements, reliable operation of the generating facility is expected for at least 25 years.
Estimated data
Mass Flow and Performance
The minimum total productivity of a boiler house and thermal power plant is from 5 MW thermal fuel, which corresponds to 12 – 15 000 tons of fuel per year and 3 MWh / electrical power., which corresponds to 30 000 tons of fuel per year, respectively, with an LHV of 11-12 MJ / kg.
The facility will consist of equipment such as a feedwater preparation plant for a boiler, a fluidized-bed boiler, a waste heat boiler, a superheater, a generator, a turbine, an flue gas treatment system, a sewage treatment plant, an ash silo and other auxiliary equipment.
Key data on emissions
The parameters provided below are guaranteed provided that the morphological composition of the MSW and, consequently, the SRF will correspond to the parameters specified by the client. Limit concentrations of harmful impurities in flue gases accordance with the norms of Europe (2000/76 / EC)
Data on emissions
| Parameters | Per Hour | Per Day | ||
| 97% | 100% | |||
| CO | – | 100 | 50 | mg/m3 |
| SOx as SO2 | 50 | 200 | 50 | mg/m3 |
| HCl | 10 | 60 | 10 | mg/m3 |
| HF | 2 | 4 | 1 | mg/m3 |
| Dust | 10 | 30 | 10 | mg/m3 |
| Total Organic Carbon (TOC) | 10 | 20 | 10 | mg/m3 |
| NOx as NO2 | 200 | 400 | 200 | mg/m3 |
| During measurements | ||||
| Cd + Tl | — | 0,05 | — | mg/m3 |
| Hg | — | 0,05 | — | mg/m3 |
| Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V | 0,5 | mg/m3 | ||
| Dioxins / Furans | — | 0,1 | — | ng/m3 |
Standard conditions: 273K, 1013 mbar, 11% O2, adjustment only for> 11% O2
Design Ratings
| Fuel | SRF | |
| Amount | kg/ | – |
| Humidity/moisture content | w-% | 15-20 (approximately) |
| Ash content | w | 10-15 (approximately) |
| LHV | kJ/kg | 11 000 – 12 000 |
Elementary analysis
| N | w | n\d |
| S | w | n\d |
| Cl | w-% | n\d |
| F | w-% | n\d |
Data on fuel
- Component composition and morphology of SRF
- Fuel fraction size:
- < 100 mm according to CEN Standard EN,
- < 10% less than 6 mm, 90% less than 75 mm
- Absence of ground material, foil, etc.
- Bulk density 150 – 200 kg / m³
- Ash sticking point: > 1 100°C
Concept
- The reception system, processing, storage and control of raw materials stock
- Fluidized Bed Boiler
- Waste heat boiler, multicyclone and economizer
- A multicyclone system is a cyclone tube for centrifugal separation of ash particles from a gas stream. The unit is supplied complete with pressure take-off fittings, ash bins, supports and manhole covers. Carbon steel casing with external insulation and cladding
- Generator and turbine
- Flue gas cleaning with absorber / bag filter / silos
- Steam water cycle with water demineralization unit, deaerator, boiler water tank, cooling
- Water softener and cooling tower
- Chemical processing and storage
- Compressor station
Process data
- Combustion temperature 850-950 °C
- The presence of exhaust gases in the furnace > 3 sec
- The temperature of the exhaust gas at the inlet of the utilizer 850-950 °C
- Exhaust gas temperature at the outlet of the utilizer 190-220 °C
- Flue gas outlet temperature 190-220 °C
- The temperature of the exhaust gas at the outlet of the bag filter 120-130 °C
- All consumables and waste will be calculated in the next step
Fluid Bed Furnace
The technology is characterized by its own furnace design, which has a number of mechanical and technological advantages. Optimum combustion conditions guarantee low emissions of NOx, CO, dioxins and other volatile organic substances, while at the same time the shape of the furnace makes it possible to efficiently arrange the conveying devices.
Fuel is fed into the fluidized bed furnace by the loading device into the air zone of the fluidized bed under the tuyere bottom of the furnace. A rotating loading device ensures an optimal distribution of sludge over the “fluidized bed”, which is important for the combustion process and the quality of the flue gas (minimum CO and NOx).
There is a layer of sand above the tuyere bottom. Sand is maintained in suspension by the flow of air coming from below.
This layer of sand grinds and crushes the incoming fuel. The water contained in the fuel evaporates and the organic components burn out. Inorganic components are grinded and discharged in the form of ash by flue gas, which leaves the furnace through the upper part.
To heat the combustion air during the start-up of the unit, a start-up burner is supplied.
The optimal operating temperature of the furnace is about 860-870 ° C.
Pressure regulation
The pressure in the combustion zone is regulated by a flue gas fan, which is located in front of the chimney.
Air supply
A fluidized bed blower supplies the required amount of air in order to create a fluidized bed and combustion.
Combustion air is discharged from the hopper by a fluidized-bed air blower with a motor with a frequency converter. Part of the air is used chilled to cool the injectors and sight glasses of the furnace. The rest of the air is heated in two stages in heat exchangers to approximately 550 ° C.
Starting burner
During the “cold start” of the furnace, thermal energy is produced by a start-up burner that runs on natural gas or fuel oil and is located in the air zone of the fluidized bed.
Gas (or fuel oil) can also be used to maintain combustion when burning fuel with a low calorific value or lower dry material content than specified in the design calculations. In this case, gas is supplied through a series of injectors mounted in the fluidized bed zone.
The duration of the start-up of the fluidized-bed furnace until the operating temperature is reached depends on the initial temperature in the furnace and averages:
For a fully cooled furnace, approximately 12-15 hours
For an furnace with a temperature of 500 ° C approximately 5-6 hours.
Ash and sand system
The ash generated during combustion is carried out by flue gases together with a small amount of sand with a reduced size of sand grains as a result of abrasion in a “fluidized bed”. Therefore, regular addition of fresh sand is necessary to replenish the sand layer.
Sand loading
The “fluidized bed” contains quartz sand with an average grain size of 1-2 mm.
Sand is supplied in bags and fed to a pneumatic sand conveyor, which feeds sand into a sand silo. Sectional sand dispenser allows you to adjust the discharge of sand from the silo into the furnace.
Sand is added to the silo by the operator. The need for sand loading is signaled by a measuring device for measuring the pressure drop located above the “fluidized bed”.
SNRC system
To reduce the NOx formation, the temperature in the furnace is maintained at 850-870 ° C. However, it should be mentioned that, under certain operating conditions, more NOx may be formed in the furnace than is permitted according to acceptable values. For these purposes, a selective non-catalytic concentration reduction system (SNCR) is used.
Ammonia water is delivered in trucks and stored in tanks for ammonia water. Dosing pumps allow a controlled supply of ammonia water to the injectors located in the upper part. Injectors are located near the entrance and at the beginning of the flue gas pipeline from the furnace to the recovery boiler, to ensure sufficient mixing and reaction exchange between ammonia water and flue gases. Installing one pump for each injector provides maximum efficiency and reliability of the NOx reduction process. Each injector is cooled by air and supplied with compressed air to spray a solution of ammonia water.
We expect a low need for lower NOx concentrations under certain operating conditions to comply with emission standards. The amount of ammonia water is controlled from the control room by installing pumps on a specific flow volume for each injector in order to achieve a constant NOx concentration below the allowable limit. With such a volume of the required amount of ammonia water, the incorrect (erroneous) dosage can be ignored.
Heat recovery (waste heat boiler)
Flue gases from the furnace enter the recovery boiler. The recovery boiler cools flue gases to approximately 190 ° C, which is necessary for their purification. The heat released in this case is used for generation.
The system has heating surfaces in the active area of the fluidized bed boiler combined with heating surfaces in the recovery boiler.
Experience has shown that a special boiler cleaning system is not required. However, the boiler is designed so that the installation of a cleaning system can be set in the future. During maintenance, the boiler can be cleaned with water or compressed air.
When generating electricity, a generator, a turbine and superheaters are supplied.
Flue gas cleaning
The flue gases leaving the recovery boiler have a temperature of about 190 ° C and contain combustion products and harmful impurities, including acid gases and ash.
Complete flue gas cleaning includes the stage of dust removal in a bag filter (or activated charcoal absorber).
Particles of the gas stream are captured in a bag filter with pulse cleaning of the bags. The system includes a housing, tube boards, funnels, fabric filter material, cells, bag filter supports, inlet and outlet manifolds, inlet rotary (wing) and outlet poppet valves, cleaning system components, funnels, funnel heaters, funnel inspection hatches, ash level sensors, bag filter supports and shut-off valves. The configuration of the system type (“penthouse”) with an overhead crane and telfer.
Compressed air manifolds are provided for the cleaning system of each module. They include all the necessary devices, valves, purge pipes and nozzles. Compressed air connections (other suppliers) must be provided for the manifold of each module and for each damper. The air must be cleaned and drained to -40 ° under pressure> 100 psig. This is required to ensure the operation of the bag filter.
Flue gas fan
The flue gas fan transports cleaned and heated in the heat exchanger the flue gases into the pipe. The fan creates the necessary pressure reduction to create draft and to create the possibility for the flue gases generated during combustion to be routed through all plant facilities, such as heat recovery and flue gas cleaning.
The fan can be washed with water if necessary. In the event of a fan breakdown or a power outage, the combustion process is immediately interrupted and gas emission ceases. Since the pressure created by the fan does not increase instantly, the necessary exhaust of flue gases during this period is provided.
The fan is equipped with a motor with a frequency converter and a control measuring device for measuring pressure, which measures the pressure in the air chamber for burning the furnace and maintains the pressure in the system below atmospheric pressure throughout the flue gas treatment area.
Chimney
A chimney is used to release purified flue gases into the atmosphere. The inner diameter of the pipe provides a gas flow rate of 15-20 m / s. To maintain noise protection, a silencer is installed between the flue gas fan and the pipe.
The necessary control devices for continuous measurement of flue gas parameters are installed in the pipeline before exiting into the pipe. This equipment includes all the necessary probes for continuous measurement of the concentration of O2-, NOx-, CO- and SOx, temperature, pressure and flue gas flow, as well as the necessary condensate discharge and piping systems, including monitoring. Optional random sampling units (dust, HCl, HF, CxHy, heavy metals, Cd, Hg, PCDD / PCDF’s as TEQ) are also supplied.
Ash transportation
Ash is collected in an ash silo. Using conveyors and sectional dispensers, it is discharged from the filter and fed to ash tanks. Using compressed air, the ash is discharged portion wise into an ash silo.
The silo is equipped with two level measuring instruments and high pressure protection. A pneumatic shaking system is provided for loosening the ash in the silo. The ash silo is equipped with a self-cleaning dust filter.
A sectional dispenser and a conveyor for wet ash discharge are installed under the silo, where the ash is mixed with waste water and unloaded onto trucks using manual control.
Natural gas
Natural gas is supplied through an existing pipeline.
The distribution system provides the incinerator, and in particular:
- Burner to start
- Additional fuel furnace injectors
The natural gas distribution system will be designed and installed in accordance with safety regulations. All necessary pressure monitoring devices, shut-off, isolating and other valves will be included in the scope of supply.
Drinking water
Water for the incinerator is required for the following installations:
- Sanitary units
- Process support (installation of feed water for the boiler, etc.)
- Factory cleaning
- Emergency showers
Boiler feed water treatment plant
A feed water treatment plant for the boiler is supplied for the production of demineralized water.
Water for the boiler will be prepared at the demineralization plant. Drinking water will be used to prepare this water.
This installation includes all auxiliary installations and devices for softening, regenerating and neutralizing water. Small amounts of reagents such as NaOH and HCl are used in the process.
Analyzes of drinking water are necessary for a detailed calculation of the feedwater treatment plant for the boiler.
Control
Management is carried out using a central processor located in the central control room.
Individual installations, especially those supplied as a single unit, are monitored from local control panels. These panels are connected to the main busbar control system or electronic connections. The necessary protective devices for the plant are adapted to the changing operating parameters of the process (start, shutdown, normal operation and emergency shutdown).
In the event of a major malfunction, the plant stops automatically to ensure factory safety. The start-up and shutdown of individual plant installations and the entire plant are carried out in semi-automatic mode.
Data from installations supplied by a single unit, measuring instruments and alarms are transmitted via an information transmission network to a central processor. Control design circuits that are not included in the supply of equipment supplied by a single unit are generated inside the logical processor system.
Most standard control functions can be activated automatically.
Staff needs
he boiler room / TPP operates non-stop, the work is carried out in 3 shifts.
For normal operation and maintenance of the plant, we recommend the following personnel:
1 day shift manager. If the manager does not have the qualification of a process engineer. This manager must be assisted by a process engineer who will control the process and operation of the plant. Process engineer provides operational support and coordinates the necessary maintenance.
2 operators per shift. At least one operator must have technical education and one electrical engineering, and have experience working with instrumentation and control. They should be able to solve simple (not very complex) problems during the night shift on their own.
For shift work there is required staff for four to five shifts. It is necessary to take into account vacation time and absence due to illness.
Optional 2 mechanics for small technical work.
During scheduled maintenance:
1 specialist in electrical work during one of the shifts.
1 person for measuring instruments and process control systems during one of the shifts.
1 person for cleaning and maintenance work during the day shift
One of the aforementioned persons on the shift must have a license to work with the recovery boiler.
