Grate Firing Systems
Whether in power plants for pure steam and electricity generation or in thermal waste-to-energy plants, Power Service Solutions GmbH‘s firing systems are used in almost all areas of energy conversion and are always optimally adapted to the specified requirements.
Environmentally friendly incineration requires special concepts and measures for domestic and municipal waste, commercial waste, refuse-derived fuel (RDF), residual waste disposal and biomass of all kinds. Depending on the waste calorific values, different grate systems are used. Medium and high calorific value waste fuels require grate bar cooling systems, such as our own water-cooled moving grate system. Low or medium calorific value waste fuels, use patented air-cooled grate bars.
The Power Service Solutions moving grate is characterized by its robust design and high throughput capacity. External hydraulic drives control the feed and return strokes of the movable rows of grate bars in each grate zone in accordance with the control requirements. The fixed and moving rows of grate bars are arranged alternately one behind the other in a grate track. Enabled by the PSS grate bar design, the uniform motion sequence and the long stroke movement in the feed result in a smooth furnace operation. In contrast to a short stroke process, this motion sequence is characterized by less wear. Another advantage of the long stroke is the additional cooling effect due to the overlapping of the grate bars and longer life.
In addition to the moving grate system, a Power Service Solutions roller grate system can also be used depending on the application. The robust roller grate system has a modular design consisting of six grate rollers. It is used for low or medium calorific value residual materials. In continuous alternation, part of the roll circumferential surface passes through the furnace, while the side facing away from the furnace is air-cooled. This alternation reduces the thermal load on the grate surface.
GRATE BARS FOR MOVING GRATES
The selection of the grate bar lining depends on the specific energy potential of the fuel: air-cooled grate bars are used for low calorific value waste fuels and water-cooled grate bars are used for higher calorific fuels, permitting higher thermal loads.
The design of the grate system is constructed in a way that a change between water-cooled and air-cooled grate bars can be made at any time without any design change. In the transition area from low to higher calorific value wastes, it is possible to combine both types of cooling. The grate bars of the high thermal load grate zones are cooled by water, while the grate bars of the burnout zone are cooled by air. The grate surface, developed by Power Service Solutions, enables a process optimized reduction in the primary air ratio, together with a reduction in excess air, controlling primary NOx emissions, without impacting grate bar life.
Economic aspects
- Availability > 8,000 h operation / year
- Increased operational reliability
- Inspection intervals extended
- Reduction of ongoing maintenance costs
- Increased service life due to our reversible and wear end grate bar technology
- Reduced spare parts inventory.
Air-cooled grate bars
Our patented air-cooled grate bars are designed for longer service life. This is achieved by a second wear face concealed behind the head face and thus protected from temperature induced corrosion. In the event of thermal wear of the outer head surface, the second wear face ensures the continued function of the grate bar and thus an extension of the overall service life. The grate bar can also be supplied as a reversible grate bar for two-ended use and a further extension of the service life observed.
Area of application
Unrestricted usability for low up to medium calorific values.
Water-cooled grate bars
The cooling water ducts are cast into the iron grate bars, which ensures water-tightness even at higher temperatures. Furthermore, the cast-in iron ducts guarantee a defined flow. This avoids vortex-induced dead spaces of angular ducts, which entail a risk of overheating. At the same time, an optimum cooling effect of the entire grate bar surface is achieved.
Area of application
Unrestricted usability for medium up to high calorific values.
Ash removal and purification systems
Slag removal and ash handling systems of various types have been part of Power Service Solutions production and scope of supply for many decades. This applies both to the removal of slag from the grate firing system and to ash transport from all other ash accumulation points within the thermal waste utilization plant.
Scope of delivery
- Ram deslagger
- Wet deslagger apron feeder
- Trough chain conveyor
- Single strand chain conveyor
- Screw conveyors
- Lump crushers
- Scraper conveyors
- Vibrating feeders
- Rotary valves
- Single and double pendulum dampers
- Gate valves
- Nozzle conveyors
- Belt conveyors.
Advantages
- Robust design
- Efficient power transmission
- Maintenance friendly design
- Safe ash discharge
- Cooled and dry ash (15-20% residual moisture)
- Adaptability to downstream aggregates
- No water treatment for overflow water
- High efficiency
- Low conveying speed
- High availability
- Low water consumption
- High operational reliability
- Long service life of wear parts
- Low operating and maintenance costs
- Particularly suitable for the transport of bulky
- and large-sized materials.
Ram deslagger for grate slag
Robust, efficient and low-maintenance.
The deslagger consists of a solid sheet steel housing with an internal drive shaft and a discharge ram. The drive shaft is driven by external hydraulic cylinders.
Apron feeder for grate slag
Stable and durable in any situation.
The trough of the wet deslagger apron feeder consists of a solid steel plate construction with stiffeners. The apron feeder consists of a double strand forked link chain with welded towing arms and the bolted apron feeder elements.
Trough chain conveyor for grate drop-through ash
The trough chain conveyor is designed as a 2-strand chain conveyor. A forged fork link chain with towing arm is used as the conveyor chain. The main trough is horizontal and the drive segment and the return segment are each arranged in a sloping position so that the drive and return shafts with their respective shaft bearings are located above the water level.
