Blue Flame Stoker Commercial biomass hot water boiler and steam generation

Introducing the Blue Flame Stoker, the revolutionary solid fuel heating system. Designed and manufactured to assure the most efficient combustion of solid fuels, while maintaining low emissions. The Blue Flame Stoker is a commmercial size heating system and steam generation unit designed to burn biomass, wood or coal and produce up to 25 Million Btu per hour.

Max Ox biomass gasification boiler 370 K Btu

Blue Flame Stoker coal wood & biomass boiler - a closer look

Boiler System

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Blue Flame Fire Tube 3-pass boiler
Boiler Type "C" Style, Three Pass, Low Pressure Boiler rated for 30 Psig water pressure (other pressures available). Three Pass design provides maximum heat transfer with low stack temperature. The boiler is designed and constructed to the A.S.M.E. low-pressure boiler code.

The boiler's extra large combustion volume assures complete combustion of solid fuels, clean firing and unrestricted gas flow. The large firebox with arched crown sheet provides and exceptionally high proportion of the primary (radiant) heating surface which is many times more efficient than secondary (indirect) heating surface. The firebox boilers are used in automatically fired Solid Fuel systems all over North America. Supplied boiler horsepower ranges from 50 - 300 BHP (other sizes available).

Special Boiler features used for Solid Fuel combustion systems:
  • ASME Boiler Code Certification
  • 3-Pass full wet back design for maximum durability and economy
  • Open furnace bottom for stoker installation
  • Hinged furnace access door; front, rear or side 16 or 20 inch diameter
  • Custom rear flue gas box outlet
  • Abundant heat transfer surface per boiler horsepower
  • Outstanding inspection access as well as quick and easy maintenance
  • Flushout and inspection openings are 3x4 inch hand-hole type.
  • Covered with mineral insulation and steel jacket

Blue Flame Stoker Base

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Blue Flame stoker base

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Blue Flame endless chain grate
The stoker consists of steel base with factory installed:
  • Hi temperature insulation and refractory
  • Combustion and over-fire air system
  • Automated ash removal
  • Chain-grate
The Chain-grate stoker uses endless chain, which is constructed to form a support for the fuel bed. The chain travels over the sprockets mounted at the front of the stoker. The stoker chain links are cast from a special high heat resistant cast iron. Chain links are designed to transport most of the Solid Fuels during the combustion process.

The stoker base is constructed of 0.250" (or thicker) mild steel. The stoker walls are lined with two layers of High Temperature insulation (for a total thickness of 4"). The use of multi-layer insulation assures low stoker surface temperature. The primary part of the combustion chamber is lined with 9" firebrick. The remaining part of the combustion chamber is lined with 9" refractory. The use of firebrick and refractory combined with high temperature insulation guarantees good heat radiation, which enhances fuel combustion.

The back of the stoker base is equipped with hinged, large access door c/w sight glass. The door (lined with refractory) provides an easy access to the combustion chamber for periodic inspections. Large (4" diameter) sight glass enables to view Solid Fuel combustion without opening the back door. The chain grate is driven by a hydraulic motor, which enables it to move at a very low speed. The main advantage of the moving chain grate is that the fuel falls on the chain grate, and combustion is completed as it moves slowly through the base. The ash remains on the grate and falls onto the main ash removal auger as the grate turns around.

Combustion Air

Blue Flame stoker at full combustion
The "Grate" wall of fire

In order to achieve a complete combustion of all combustible components of Solid Fuel with all the Oxygen, sufficient space, Time, Turbulence and Temperature high enough to ignite the components must be provided.

Combustion Air control is one of the most critical elements for proper Solid Fuel combustion. Efficient solid fuel combustion depends on both, primary (combustion) and secondary (over fire) air. Combustion Air provides the basic oxygen supply for solid fuel burning. Secondary Air is injected into the upper section of the combustion chamber to combust the unburned gases.

The stoker base is divided into zones (under grate wind boxes) from front to back. The purpose of the wind boxes is to deliver the primary (combustion) air for solid fuel burning. The combustion air is delivered through attached plenum by a direct drive combustion air fan driven by Variable Speed Drive (VSD). The main plenum branches off to the individual wind boxes and is equipped with hand-operated dampers. Hand-operated dampers are provided to regulate the flow of air to the zones to compensate for irregularity in the fuel bed depth. The total supply of combustion air delivered is modulated using VSD and is directly proportional to the amount of fuel delivered to the Combustion Chamber.

The amount of theoretical combustion air required is carefully calculated for each individual Solid Fuel used. Since the majority of the combustion occurs directly above the stoker grate, the injection of secondary air assures proper oxygen mixing and complete combustion of carbon monoxide and volatile gases. The secondary air is injected to the combustion chamber (above the grate) using a high-pressure blower.

Fuel Handling

Blue Flame fuel handing system when configured
to burn coal

Blue Flame stoker inside the burn chamber
Video courtesy of Burt's Greenhouses, Odessa Ontario

The Fuel Handling system is designed to convey coal and other fuels, such as wood chips and agricultural waste. Included is a twin-screw fuel-metering conveyor that is designed to transfer fuel from customer supplied hopper bottom bin to the fuel injector fan. The system consists of:
  • Twin-screw auger
  • Gearbox motor
  • Fuel injector fan

The feeder-and-distribution system utilizes a high-pressure blower to inject the fuel into the combustion chamber. This type of system has a wide application with respect to both, the fuel that can be handled and the boiler sizes to which they can be applied. This fuel handling system functions to vary the supply of solid fuel to the furnace and to provide even distribution on the chain grate. Variations in performance of the fuel injection fan, due to changes in fuel size are corrected by means of an external damper adjustment. The fuel feed ratio is directly related to the power demanded by the boiler control system. The use of a Variable Speed Drive (that powers the gear box) enables modulation of the feed rate from a few pounds of fuel per minute to a few hundred pounds.

Ash removal

Blue Flame automated ash removal system

The stoker incorporates an automated ash removal system as follows; an ash cross auger is installed into the stoker base within each individual wind box (this enables it to remove any ash that drops through chain links), the turn-around box and main ash auger. As the chain moves forward during the system operation the ash will drop-off the end of the moving chain grate onto an in-base trough fitted with main ash auger. The main ash removal auger will then transport the ashes out off the base to a designated collection outside the building.

All the ash augers are driven by hydraulic motors powered by hydraulic system installed onto the back of the stoker base. The use of the hydraulic motors enables an easy way of adjusting the speed and the torque required to turn the augers. All of the ash removal functions are fully automated and are controlled by PLC from a supplied electrical panel.

The frequency of ash removal is determined by the system load, the type and the amount of Solid Fuel burnt. The PLC touch screen control panel allows the user to make all the necessary changes as required.

Automated Soot Blowers

The soot blowers are factory installed into the boiler (in some cases on site installation is required). The function of the soot blowers is to eliminate any soot build-up within the boiler tubes, thus increasing its heat recovery efficiency. Included is an automatic soot blower control system. PLC controlled soot blowers are programmed to blow the tubes at predetermined intervals, guaranteeing a maximum boiler heat recovery 24 hrs a day. Compressed air (min. 40SCFM at 100PSIG) is required for proper operation of the soot blower system.

Control Panel

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Blue Flame stoker base
The Electrical Control Panel consists of a CSA approved steel enclosure, with lock, approximate dimensions (36"x 36"x 8"), complete with:
  • One (1) PLC
  • One 8" Color Touch Screen panel
  • All motor controls (including VSDs), indicator lights
  • Audible alarm
  • All necessary terminal blocks to make inter connections.
All of the above are completely internally wired prior to shipment. The Control Panel is designed to operate the Chain Grate Stoker, Twin-Screw Fuel Feed Conveyor, Automated Ash Removal Augers, Combustion Air Fan, Exhaust Air Fan and Automated Soot Blower.

System Function - All motors will have Hand/Off/Auto selectable switches. During a normal system operation all the switches will be in the "Auto" position. The "Hand" (manual) mode will operate all the motors at a pre-set speed. The "Hand" option will also be used during equipment testing and troubleshooting. On the start-up, the system will automatically start all the functions (fuel feed rate, combustion air fan speed, exhaust air fan speed) at a pre-set values.

senor monitored feed auger
Blue Flame touch screen display
On/Off time and cycle times for Chain Grate and Ash Removal Augers will be pre-set by the user and stored in the PLC. The set-up will be performed via the Touch Screen Panel directly interfaced with the PLC. The Touch Screen will display all the functions of the system (including alarm status). The set-up screen will be password protected (for authorized personnel only).

Control Functions - A type J thermocouple will be used in combination with the temperature controller, mounted directly on the Control Panel. Temperature controller will have a PID function with 4-20 mA output to control the fuel feed rate and combustion air volume (in order to maintain a proper fuel combustion).

Hold Fire - Used only during the periods of low heat demand. If the system reaches the set point temperature the system will shut down. If the temperature remains at the set point for a long period of time the system will start up at a pre-set time intervals in order to maintain fire. The time interval between start-ups is selectable by the user.

Dust collector

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Blue Flame multi-cyclone
dust collection system
The dust collector is designed to eliminate most of the fly ash, generated during Solid Fuel combustion, that otherwise would be discharged from the chimney. The heart of the system is a multi-cyclone design complete with exhaust blower and fly ash removal auger. The speed of the exhaust fan is controlled by a Variable Speed Drive coupled with Photohelic® gauge in order to maintain a constant negative pressure inside the combustion chamber.

The dust collector system is sized and specifically designed for the supplied stoker. The fly ash is collected in the bottom hopper of the dust collector system and discharged into ash removal system. The use of the air-loc valve between the bottom of the hopper and transfer auger prevents any air leakage outside the dust collector.

Industrial | Commercial size biomass boilers

The Blue Flame boiler Btu output can reach 25M Btu. If you are looking to build and heat greenhouse structures or poultry housing or need a commercial grade alternative for heating with sawdust, waste-wood, coal or biomass, the Blue Flame boilers achieve high output with great economic savings. While biomass fuel is readily available, it is important to research the kind of fuel most common in your area. Contact Total Energy Solutions to see what fuel options are in your area. Make plans to store additional fuel onsite to allow for any drying that is needed as well as to avoid fuel shortages. For a more detailed look at common bio-mass fuel types click here.

Blue Flame Stoker hot water boiler commercial applications

  • Greenhouse gasifier boiler heat - single or multiple green houses
  • Heat Chicken houses
  • Poultry farming
  • Hog Barns
  • Heat Mushroom houses
  • Small Manufacturing facilities
  • Warehouses
  • School buildings
  • Municipal buildings
  • Many other applications for indoor wood boilers and biomass sawdust stoves