Abstract: A dryer performance optimization system comprising a dryer having an inner wall and being adapted to rotate at variable speeds and a variable frequency drive being adapted to vary the rotational speed of the dryer. The preferred system also comprises a baghouse having an inlet end being adapted to receive exhaust gas from the dryer and an outlet end and a controller being adapted to control the temperature of the exhaust gas from the dryer. A method for controlling the temperature of exhaust gas in a baghouse comprising providing a dryer performance optimization system as described herein and varying the temperature of the exhaust gas from the dryer by varying the rotational speed of the dryer.

Abstract: An assembly for processing green biomass materials from two separate feed sources for use as a fuel pellet includes a drying assembly, a torrefaction assembly and a heating assembly. The drying assembly is adapted to convert the green biomass material obtained from a first source to white biomass material. The torrefaction assembly is adapted to convert green biomass material obtained from a second source to torrefied biomass material. The heating assembly provides heat for both the drying assembly and the torrefaction assembly.

Abstract: An assembly for processing green biomass material for pelletizing into a fuel pellet includes a heating assembly, a drying assembly and a cooling assembly. The heating assembly heats a thermal fluid to a temperature within the range of 200° F. to 550° F. The drying assembly includes a rotating dryer drum that has a plurality of thermal fluid tubes therein. Material that is dried in the dryer drum is conveyed to a rotating cooling drum that has a cooling tube extending along the interior thereof. A nozzle is mounted on the end of the cooling tube to discharge cooling fluid on the material therein, and a plurality of flights are mounted on the interior of the cooling drum and arranged to direct material from the inlet to the discharge outlet as the cooling drum is rotated.

Abstract: A burner assembly including a housing having an air inlet, a burner end having an opening, a longitudinal axis extending generally from the air inlet toward the burner end, a motor, an impeller mounted in the housing and being in fluid communication with the air inlet, operatively connected to the motor and adapted to direct air from the air inlet toward the burner end, a coal tube adapted to convey coal toward the burner end, a coal inlet adapted to convey coal to the coal tube, a first bluff body ring, a second bluff body ring and a third bluff body ring mounted at the burner end, a flame bridge disposed between the first bluff body ring and the second bluff body ring, and an igniter mounted in the burner end and being adapted to ignite the air and fuel mixture in the burner end to produce a main flame.

Abstract: A burner assembly including a housing having an air inlet, a burner end having an opening, a longitudinal axis extending generally from the air inlet toward the burner end, a motor, an impeller mounted in the housing and being in fluid communication with the air inlet, operatively connected to the motor and adapted to direct air from the air inlet toward the burner end, a coal tube adapted to convey coal toward the burner end, a coal inlet adapted to convey coal to the coal tube, a first bluff body ring, a second bluff body ring and a third bluff body ring mounted at the burner end, a flame bridge disposed between the first bluff body ring and the second bluff body ring, and an igniter mounted in the burner end and being adapted to ignite the air and fuel mixture in the burner end to produce a main flame.

Abstract: An apparatus for making asphalt paving material includes a dust collection and distribution system by which aggregate dust that is collected during the heating and drying of aggregate may be introduced into the mixing chamber and distributed over a substantial portion of the area of the mixing chamber. By distributing the aggregate dust over a broader area of the mixing chamber than has been previously known, the mixing effort required to achieve a thorough blending of the dust into the mixture is reduced, and the quality of the asphalt paving composition is improved.

Abstract: A combined soil remediation and HMA plant is provided having a rotary dryer, a rotary soil incinerator, and a refractory lined duct connecting the incinerator to the dryer and serving as a conduit via which hot gases, forming the primary and possibly sole heat source used to heat raw aggregate in the dryer, are conveyed from the incinerator to the dryer. The duct also acts as an afterburner in which volatile organic compounds, particles of contaminated dust, and other combustible products not destroyed in the incinerator are destroyed. The plant further includes a mixer 1) receiving both reclaimed soil from the incinerator and heated and dried aggregate from the dryer and 2) mixing both materials with liquid asphalt and possibly RAP and/or dust from the system's baghouse assembly to form HMA.

Abstract: A premix burner assembly for heating the combustion chamber of a dryer for an HMA plant, soil remediation plant, or the like is designed to meet the very low emission limitations that are imposed in certain areas such as the southern portion of California. The burner assembly includes a burner, a primary nozzle, an air source connected to the burner, a fuel source, and a fuel injection system connected to the fuel source and to the burner. Premixing is achieved through the supply of a gaseous fuel from the fuel injection system into the burner upstream of the primary nozzle so as to lead to nearly complete premixing of the air and fuel prior to discharge into the combustion chamber, thereby permitting combustion of the fuel with only very small amounts of excess air. Burner efficiency is increased and emissions are further reduced by employing air distribution and control devices upstream of the fuel injection system and by carefully controlling the supply of both air and fuel to the burner.

Abstract: A dryer drum coater has an internal recirculation cylinder for promoting the recirculation of combustion products so as to entrain and incinerate blue smoke formed when heated and dried virgin aggregate is mixed with other asphaltic products such as RAP and/or liquid asphalt in the dryer drum coater. The recirculation cylinder acts to extend and strengthen natural eddy currents formed during operation of the coater such that combustion product recirculation which would normally extend only in the end area of the flame extends far enough toward the base of the flame to entrain the blue smoke and to draw the blue smoke into the base area of the flame. The cylinder may comprise a refractory lined stainless steel shell or may be formed from tee flights of the type used in the combustion zones of dryer drum coaters.

Abstract: An HMA plant has a catalytic reactor which can effectively and reliably reduce VOC and NO.sub.x emissions produced during plant operation. The reactor effectiveness is enhanced by exhausting the gas stream from a primary dryer of the plant at a sufficiently high temperature for effective catalytic reaction. Since withdrawal of gases from the dryer at these elevated temperatures necessarily reduces the effectiveness of the dryer, overall plant efficiency is maintained by using the treated gas stream from the catalytic reactor to heat further the aggregate in a secondary dryer, which is preferably a finishing dryer/mixer such as a fixed sleeve dryer drum coater. Poisoning of the catalyst is avoided by removing at least a large portion of the dust in the gas stream via a high efficiency cyclone prior to introducing the gas stream into the catalytic reactor. Ammonia or urea may if desired also be injected into the gas stream prior to its introduction into the catalytic reactor.

Abstract: A low-temperature thermal desorption (LTTD) system remediates highly contaminated soils. The system (1) reduces the concentration of vaporized contaminants exhausted from the primary treatment unit (PTU) and (2) precisely controls the concentration of vaporized contaminants exhausted from the PTU so as to permit the safe oxidization of contaminants in a secondary treatment unit without oversizing the secondary treatment unit or the baghouse. The concentration of vaporized contaminants exhausted from the PTU is reduced by drawing the vaporized contaminants into a low-pressure region of the PTU so as to contact the burner flame and by supplying this area of flame contact with a modulated supply of air to oxidize a designated portion of the vaporized contaminants within the PTU.

Abstract: A soil remediation system uses heat from remediated soil to vaporize volatiles from contaminated dust without pollution. Preferably, this remediation takes place in a dust remediator which is located proximate a primary treatment unit for contaminated soil, which vaporizes volatiles from the dust using heat from remediated soil, and which directs the volatiles into the primary treatment unit for oxidation. The primary treatment unit may comprise a rotary drum, and the dust remediator may comprise a shroud covering the remediated soil outlet end of the drum and receiving the remediated soil and the dust. The remediated soil and the dust are combined in the shroud so as to maximize vaporization of contaminants while minimizing agitation of the dust, and the combined soil and dust are then discharged together from a remediated products outlet of the shroud.

Abstract: An apparatus and method for decontaminating petroleum contaminated soil and the like, and which comprises a rotary drum dryer which is adapted to convey the soil therethrough, and which includes a burner at one end for generating a heated gas stream which passes through the dryer to heat the soil to a temperature sufficient to volatilize the contaminates. A fixed enclosure is mounted to surround the discharge end of the dryer and the enclosure receives the heated soil as it is discharged from the dryer. Any entrained dust particles which are withdrawn with the exhaust gas stream from the dryer, and which may remain contaminated, are separated from the gas stream and returned to the enclosure. In the enclosure, the returned dust is mixed with the heated soil so as to cause the dust to be heated and to release its volatile contaminates, without risk of the returned dust being again entrained in the gas stream flowing through the dryer.

Abstract: Cooling assemblies of the cooling apparatus each include an air atomizing spray nozzle located within a heated cooling chamber. An outer conduit interconnects the spray nozzle of each assembly and a source of cooling water. An inner conduit within the outer conduit interconnects the spray nozzle and a source of compressed air. Water passing through the outer conduit cools both it and the inner conduit. The outer conduit includes a flexible section that interconnects rigid sections and allows the latter to freely undergo differential expansive and contractive movement. Generally conical spray patterns produced by the spray nozzles form a circular array within the cooling chamber. Adjacent ones of the spray patterns abut each other and another nozzle spray pattern produced by a spray nozzle located generally centrally of the array and of the cooling chamber.

Abstract: A rotary drum dryer is disclosed which is useful in the production of asphalt paving composition. The drum incorporates a burner which defines a combustion zone, and a novel dam and flight construction is mounted to the interior of the drum so that the flights surround the combustion zone. The dam is adapted to retain and raise the level of the aggregate flowing through the rotating drum so that the flights pass through the aggregate in the bottom of the drum, and the flights collect a portion of the aggregate on their top surfaces and carry the collected aggregate to an elevated discharge point, where the aggregate drops back to the bottom of the drum. The flights serve to shield the metal wall of the drum from the radiant heat energy of the burner flame which would otherwise result in its rapid deterioration, and they also serve to permit the aggregate to be effectively exposed to the radiant heat.