A fluidized bed gasification system which comprises a fluidized bed gasification reactor having a bottom ash discharge outlet below the reactor, wherein an L-valve is used to control the rate of bottom ash discharge. The L-valve uses an aeration port located on distal side of the L-valve vertical pipe at a location that is above the center line of the horizontal pipe. Also provided are methods of controlling the bottom ash discharge as well the fluidized reaction bed height of the system.

A pellet stove includes a hopper for storing pellets, a basket for receiving the pellets by gravity, a duct for conveying combustion air to the basket, and a conduit for conducting heated air away from the basket. The position of the basket is adjustable, such as by raising and lowering it, or by rotating it, so as to control the number of pellets in the area of most intense combustion. One or more burn plates, positioned below the basket, provide platforms on which pellets falling through the basket can burn down to a smaller size. The pellet stove requires no external source of power. The stove so constructed enables quiet, efficient and clean burning of the pellets.

A pellet stove includes a hopper for storing pellets, a basket for receiving the pellets by gravity, a duct for conveying combustion air to the basket, and a conduit for conducting heated air away from the basket. The position of the basket is adjustable, such as by raising and lowering it, or by rotating it, so as to control the number of pellets in the area of most intense combustion. One or more burn plates, positioned below the basket, provide platforms on which pellets falling through the basket can burn down to a smaller size. The pellet stove requires no external source of power. The stove so constructed enables quiet, efficient and clean burning of the pellets.

A combustion ash handling method of handling combustion ash discharged from a combustion furnace that combusts a petroleum-based fuel includes: separating the combustion ash into a heavy component and a light component by a dry-type separation technique; feeding the light component to the combustion furnace as a fuel; and recovering the heavy component. A metal such as vanadium is separated and extracted from the heavy component of the combustion ash.

A combustion ash handling method of handling combustion ash discharged from a combustion furnace that combusts a petroleum-based fuel includes: separating the combustion ash into a heavy component and a light component by a dry-type separation technique; feeding the light component to the combustion furnace as a fuel; and recovering the heavy component. A metal such as vanadium is separated and extracted from the heavy component of the combustion ash.

A ground supported single drum power boiler is described combining a refractory lined and insulated V-Cell floor; refractory lined and insulated combustion chamber; integrated fuel chutes configured to pre-dry wet solid fuel; top mounted fuel bin; internal chamber walls; configurable combustion air systems; and a back pass with after-burner ports and cross flow superheaters. The boiler can be configured in pre-assembled modules to minimize the field construction time and cost. An alternative embodiment is adaptable as a gasifier.

A ground supported single drum power boiler is described combining a refractory lined and insulated V-Cell floor; refractory lined and insulated combustion chamber; integrated fuel chutes configured to pre-dry wet solid fuel; top mounted fuel bin; internal chamber walls; configurable combustion air systems; and a back pass with after-burner ports and cross flow superheaters. The boiler can be configured in pre-assembled modules to minimize the field construction time and cost. An alternative embodiment is adaptable as a gasifier.

A method of combusting a sulfur-containing carbonaceous material with ash treatment includes: feeding a feed containing the sulfur-containing carbonaceous material and limestone into a furnace; combusting the feed in the furnace so as to generate preliminary fly and bottom ashes; hydrating the preliminary fly and bottom ashes to form a hydrated material; recycling the hydrated materials into the furnace so as to generate secondary fly and bottom ashes; and reacting the secondary fly and bottom ashes with a sulfuric acid solution.

A method of combusting a sulfur-containing carbonaceous material with ash treatment includes: feeding a feed containing the sulfur-containing carbonaceous material and limestone into a furnace; combusting the feed in the furnace so as to generate preliminary fly and bottom ashes; hydrating the preliminary fly and bottom ashes to form a hydrated material; recycling the hydrated materials into the furnace so as to generate secondary fly and bottom ashes; and reacting the secondary fly and bottom ashes with a sulfuric acid solution.

A method for treatment of ash from incineration plants includes: collecting ash from an incinerator; feeding the collected ash and additional feed material to a gasification/vitrification reactor; vitrifying the ash and additional feed material in the gasification/vitrification reactor, to form a slag of molten material; allowing the slag to flow from the gasification/vitrification reactor and solidify outside the gasification/vitrification reactor; gasifying volatile components in the ash and the additional feed material; combusting syngas generated in the gasification/vitrification reactor in a secondary combustion zone in the gasification/vitrification reactor; and supplying products of the syngas combustion to the incinerator to augment the thermal environments of the incinerator. An apparatus used to practice the method is also provided.