Biomass / Agriculture Waste Fired Boilers

TRAVELLING GRATE STOKER

Continuous Ash Discharge Spreader Stoker Travelling Grates are ideally suited for firing cellulose fuels like Bagasse, Briquettes, Rice husk and Wood chips. Even Coal of various grades can be fired on Travelling Grate.

The grate travels from rear to front side of boiler, while the fuel is injected into the furnace from the front. Depending upon fuel density, Pneumatics or Mechanical spreaders are used to fire various fuels and ensure uniform fuel distribution on the grate.

Grate bars are protected from high temperature by combustion air purging from underneath the grate. It cools the grate bars and keep metal temperature well within the limits even for High GCV Low Ash fuels like Imported Coal. The compartmentalized air chamber below the grate regulates the air flow across the grate for further improving the combustion throughout grate.

Travelling Grate is combination of Grate Bars, Front Shaft & Drive Sprockets, Rear Sprockets, Chain links, Front & Rear Sealing arrangement. Drive arrangement include variable frequency drive with planetary gearbox or Hydraulic Power pack arrangement

Advantages of Travelling grate stoker:

• Most suitable for sized fuels.
• High Moisture fuels like Bagasse can be successfully burnt.
• Rapid load swings can be accommodated due to large inventory of the fuel on the grate.
• Simple control.
• Rugged construction with minimum maintenance
• Self-lubricating Graphite bearings are provided for Stoker Shaft.
• High operating reliability.
• Low power consumption.

RECIPROCATING GRATE STOKER

Reciprocating Grate is best technology to fire Straw fuels. In this grate fuel is progressively moved within the combustion chamber. As the material moves forward it goes through the different stages of combustion. At first stage biomass enters the combustion chamber and is immediately exposed to the heat of the combustion chamber, which helps to dry. In Second Stage fuel gasify and release hot gases for combustion. In the Third Stage after complete combustion of fuel, only ash left to be taken out of furnace through ash hoppers.

Reciprocating Grates can be Air Cooled or Water Cooled depending upon application and Fuel to be fired.

Primary air is forced into a plenum underneath the stepped grate in order to promote drying and gasification. The secondary air nozzles are high velocity jets placed above the grates that cut across the combustion chamber in order to complete oxidation of the gases leaving the grate.

The reciprocating grates can be designed for use with low or high moisture content fuels. Solid fuels include Biomass, Waste wood, Wood pellets, Bark, Agricultural wastes such as Paddy & Wheat Straw, Walnut shells, Peanut shells and other fuels with heat content. The reciprocating grate has flexible design to allow variation in fuel size and moisture

Advantages of Reciprocating grate stoker:

• Insensitive to fuel size.
• Fuel containing maximum moisture can be successfully burnt.
• Rapid load swings can be accommodated due to large inventory of the fuel on the grate.
• Simple control.
• Robust construction with minimum maintenance, hence high operating reliability.
• Simple and rapid installation.
• Low power consumption.
• Efficient fuel feeding system using hydraulically actuated feed piston and divergent hoppers Reciprocating grate with Hydraulic unit.