Through air drying systems and methods with hot air injection

Abstract

To provide TAD systems and methods with reduced carbon footprint.SOLUTION: A system of drying or bonding materials, comprises a first component group generating a first air stream, including a combustion heater configured to generate first heated air, a mixing element acting on the first heated air to generate second heated air of a desired temperature, a hood receiving the second heated air, and a perforated cylinder surrounded by the hood to discharge cooling air, and a second component group generating a second air stream, including at least one heating element configured to generate third heated air and at least one fan in fluid communication with aforementioned at least one heating element to introduce the third heated air to the first air stream.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] "Through-air technology" is a term used to refer to systems and methods capable of passing heated air through a nonwoven web to dry or bond fibers or filaments. Examples include drying nonwoven products (e.g., tea bags, specialty paper, etc.), drying and curing fiberglass mats, filter paper, and resin-coated nonwovens, thermal bonding and drying of spunbond nonwovens, drying of hydroentangled webs, thermal bonding of geotextiles with or without bicomponent fibers, drying and curing of interlining grades, and thermal bonding of absorbent cores containing fusible binder fibers. Tissue drying is a key application of through-air technology, and systems and methods related to through-air drying are commonly referred to by the acronym "TAD." Some through-air systems use natural gas burners to provide thermal energy to the system. That is, natural gas burners may be used to heat the air so that it is exposed to materials at temperatures capable of drying or bonding the materials.

[0002] As discussed above in the "Background" section, TAD systems refer to an important subgenus within the broader genus of through-air technology systems. While the inventions disclosed herein are applicable to the broader genus of through-air technology systems and methods, for simplicity, they may be described herein in the context of TAD systems and methods. Significant challenges with TAD systems include introducing large amounts of energy (e.g., 20-60 MW) into a TAD system without sacrificing performance, controllability, or reliability, and achieving target air temperatures for the TAD from the TAD system expansion, pressure drop, air mixing, turndown, and commonly used heat exchange devices. Summary of the Invention [Problem to be solved by the invention]

[0003] The present disclosure provides a TAD system with a reduced carbon footprint that mitigates climate change associated with fossil fuel use. The TAD system may use alternative energy sources, such as hydropower, biofuels, solar, wind, heat recovery, steam / condensate heat exchange, and other carbon-neutral energy sources.

[0004] The TAD system of the present disclosure includes the following advantages: tiered energy application from various heat sources and heat exchangers; a reduced carbon footprint; an independent energy supply system that allows the TAD system to operate in conventional mode with a natural gas burner as backup; and the ability to recover low-grade heat from the TAD exhaust. The energy input can be from several suitable sources, including power, burners, and electric heat exchangers. the ability to adjust the temperature of the TAD supply; ease of maintenance, including accessibility (e.g., the hot air intake system is separate from the TAD system, allowing maintenance to be performed on the hot air intake system while the TAD system is in operation); Maintain uniformity of temperature and flow rate, and use multiple energy sources to the ability to utilize the temperature range that best suits the heat source (heat recovery from the TAD exhaust, steam, condensate, hot oil, electricity, other fluid streams, etc.); the ability to add additional heat sources or heat exchangers without redesigning or rebuilding the TAD system (e.g., being able to supplement hot air induction system components in series with already installed TAD system components); the ability to retrofit into existing TAD systems; and the ability to convert exhaust vacuum discharge into hot air induction system make-up. This ability can be used as a make-up. [Means for solving the problem]

[0005] In accordance with the present disclosure, a hot air introduction system using an alternative energy source, including a carbon-neutral energy source, is configured to supply hot air to at least one TAD system, which may include a burner system that can be used whether or not the hot air introduction system is operational.

[0006] Some aspects of the TAD system of the present disclosure may operate in accordance with known TAD system operations today, such as known fan speeds and burner speeds. The output may be used to adjust the temperature of the air entering the hood of the TAD and the air flow rate into the hood. By introducing air from a hot air induction system into the TAD system airflow as described herein, the burner energy required to heat the air to a desired temperature may be reduced compared to known techniques, and fan speeds may be varied from known techniques.

[0007] While the hot air introduction system is operating, the burner may retain its role of controlling the drying temperature at a lower flame output. Alternatively, when the hot air introduction system is not operating, the TAD system may operate in a conventional stand-alone mode.

[0008] The hot air introduction system of the present disclosure may provide the full degree of versatility when used in conjunction with at least one TAD system. The at least one TAD system may be used independently of the hot air introduction system or in conjunction with the hot air introduction system. Such a configuration allows for the use of different air systems. This allows for complete isolation, allowing for independent access, maintenance, startup, and shutdown. This system configuration also allows for seamless switching between conventional operation without hot air injection and operation with hot air injection without adversely affecting production (e.g., drying of goods).

[0009] One aspect of the present disclosure relates to a system for drying (or gluing) articles. The system is configured to generate a first air flow using a combustion heater, a mixing element, a hood, and a perforated cylinder. The combustion heater is configured to generate a first heated air. The mixing element acts on the first heated air to generate a second heated air at a desired temperature. An example of a mixing element suitable for use in connection with the present disclosure is described in U.S. Pat. No. 7,861,437, the entire disclosure of which is incorporated herein by reference. The hood receives the second heated air. The perforated cylinder is enclosed by the hood and outputs cooled air. The system is further configured to generate a second air flow using at least one heating element and at least one fan in fluid communication with the at least one heating element. The at least one heating element is configured to generate a third heated air. The at least one fan introduces the third heated air into the first air flow. The combustion heater acts on the third heated air and at least a portion of the cooling air to generate the first heated air.

[0010] Another aspect of the present disclosure relates to a method for drying an article, the method comprising generating cooled air, generating first heated air using at least one heating element, combining at least a portion of the cooled air with the first heated air to generate mixed air, heating the mixed air using a combustion heater to generate second heated air, mixing the second heated air to generate third heated air at a desired temperature, and exposing the third heated air to the article to generate the cooled air. do.

[0011] This disclosure relates to through-air systems with dryers and bonders. As will be discussed in detail below, other systems may be used, such as Yankee air systems, flatbed dryers, floater dryers, other dryers, ovens, etc.

[0012] For a more complete understanding of the present disclosure, reference is now made to the following drawings in which: See description. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a single TAD system with a hot air introduction system in accordance with an embodiment of the present disclosure. [Figure 2] 1 is a schematic diagram of two TAD systems with hot air introduction systems in accordance with an embodiment of the present disclosure. FIG. [Figure 3] FIG. 1 is a process flow diagram illustrating the operation of a single TAD system with a hot air introduction system in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present disclosure includes at least one TAD system connected to a hot air induction system that provides the energy necessary to, for example, reduce carbon emissions and evaporate moisture from papermaking webs such as tissue paper and other similar products, such as nonwoven materials. The hot air induction system may supply (e.g., introduce) hot air at an appropriate elevated temperature to the at least one TAD system to raise the temperature of the air exiting the at least one TAD system (a TAD(s) of the systems' / systems') to a desired supply air drying temperature. The desired supply air may be supplied to articles to be dried within the at least one TAD. The cooled air flow exiting the TAD that is circulated through components that heat the cooled air to a desired temperature before being inserted into the TAD may be referred to herein as "recirculated air" or "recirculating air."

[0015] The incorporation of the hot air introduction system according to the present disclosure allows the conventional TAD system design to remain largely unchanged. The hot air introduction system can be incorporated into the TAD system to mix with the recirculated air of the TAD system. The recirculated air of the TAD system can be mixed with the air supplied by the hot air introduction system before or after the main recirculation fan of the TAD system. The recirculated air of the TAD system can be mixed with the air supplied by the hot air introduction system before or after the main recirculation fan. The recirculated air of the TAD system can be mixed with the air supplied by the hot air introduction system before or after the air heater section of the TAD system. For example, the hot air introduction system can introduce heated air into the recirculated air of the TAD system upstream of at least one fired heater relative to the recirculated air flow. As a further example, the hot air introduction system can introduce heated air into the recirculated air of the TAD system downstream of at least one fired heater relative to the recirculated air flow of the TAD system. In a preferred embodiment, mixing of the recirculated air of a TAD system with the air supplied by the hot air introduction system can occur between the main fan and the air heater of the TAD system.

[0016] The hot air intake system may be implemented separately from the TAD system such that the TAD system can operate without the hot air intake system being in operation, thereby allowing for maintenance to be performed on the hot air intake system and / or The TAD system can remain operational during an unexpected interruption of operation of the hot air intake system.

[0017] Multiple heat sources may be used to heat the air entering the hot air introduction system. The air entering the hot air introduction system may come from ambient air (e.g., fresh air from around the hot air system) and / or TAD system exhaust and / or other sources. The air entering the hot air introduction system may come from a single source (e.g., ambient air only, TAD system exhaust only, etc.) or may be a combination of air from multiple sources (e.g., ambient air and TAD system exhaust, etc.).

[0018] A fan may be used to draw air entering the hot air intake system before or after the introduction of any combination of heat exchangers or other air sources. The air is gradually heated to the desired intake temperature through a given combination of heat sources and heat exchangers. One configuration involves mixing the TAD system exhaust with preheated ambient air and then passing the exhaust through a fan, a steam heat exchanger, an oil heat exchanger, and an electric heat exchanger (i.e., exchanger group). This configuration is exemplary; those skilled in the art will recognize that other configurations may be used to heat the air in the hot air introduction system. The purpose of the series of heating elements in the hot air introduction system may be to gradually increase the temperature of the air by utilizing the maximum (e.g., optimal) temperature output of each heating element. For example, the steam heat exchanger may heat the air to approximately 182°C, the oil heat exchanger may heat the approximately 182°C air to approximately 290°C, and the electric heat exchanger may heat the approximately 290°C air to approximately 450°C or higher.

[0019] An exemplary configuration of a single TAD system with a hot air introduction system is shown in Figure 1. The lines drawn in Figures 1 and 2 represent possible air flows for a system according to the present disclosure.

[0020] The TAD system includes a TA system including a perforated (e.g., multi-hole) cylinder 104 at least partially enclosed by a hood 106, at least one main fan 108, at least one air heater 110, and at least one mixer 112. D100. Although only a single main fan 108, a single air heater 110, and a single mixer 112 are depicted, those skilled in the art will recognize that the TAD system may include multiple main fans 108 and / or multiple air heaters 110 and / or multiple mixers 112.

[0021] An item to be dried is conveyed through the hood 106 along the perforated cylinder 104. Heated air at a desired temperature is flowed into the hood 106 and exposed to the item to be dried. The air passes through the item to dry it, leaving it cooler than when it first contacted the item. The cooled air then passes through the holes in the perforated cylinder 104 and exits the TAD 100 as cooled air (or exhaust air).

[0022] A portion of the cooled air exiting the TAD 100 may be recirculated back to the TAD 100. As shown, a portion of the cooled air exiting the TAD 100 may be passed through the main fan 108 to the air heater 110. The air heater 110 may heat the cooled air by burning a fossil fuel. The air heater 110 heats the cooled air and outputs the heated air to the mixer 112. The air heater 110 may include various types of air heating elements, including those known in the art and those yet to be created. For example, the air heater 110 may include at least one electric heater and / or at least one steam coil and / or at least one glycol-to-air heat exchanger and / or at least one combustion-based heating element. The at least one air heating element implemented in the air heater 110 may depend on the system configuration and the desired temperature of the air exiting the air heater 110. The mixer 112 receives heated air from the air heater 110 and outputs heated air at a desired temperature that is flowed into the TAD 100 (specifically, into the hood 106).

[0023] A portion of the cooled air exiting the TAD 100 may be bled from the TAD system to the hot air intake system by operation of an exhaust fan 114. A portion of the cooled air exiting the TAD 100 may be flowed into an air-glycol heat exchanger 116, where the cooled air (which is cooler than the air entering the TAD 100 but not yet cooled enough to be considered ambient air) heats the glycol in the air-glycol heat exchanger 116. After heating the glycol, the air may be bled from the tower of the air-glycol heat exchanger 116 to an environment outside the system. This bled air may be relatively cool and saturated (e.g., 100% relative humidity). This bled air allows the system to remove evaporated moisture and maintain the air system balance.

[0024] The hot air introduction system may include at least one air heating element. For example, the hot air introduction system may include at least one glycol-to-air heat exchanger 118 and an electric heater 120. The coil of the at least one glycol-to-air heat exchanger 118 may receive heated glycol from the air-glycol heat exchanger 116 (e.g., glycol heated by cooling air exiting the TAD 100 and passing through the exhaust fan 114). The hot air introduction system may further include at least one other heating element, such as a steam coil, other heating elements known in the art, or a heating element yet to be developed.

[0025] The heating elements of the hot air introduction system can be positioned and configured to utilize the maximum (e.g., optimal) temperature output of each heating element to gradually increase the temperature of the air. For example, the air in the hot air introduction system can first be exposed to a steam heat exchanger, which can heat the air to approximately 182°C. The approximately 182°C air can be exposed to an oil heat exchanger, which can further heat the air to approximately 290°C. The approximately 290°C air can be exposed to an electric heat exchanger, which can further heat the air to approximately 450°C or higher. This arrangement of heating elements is exemplary only. Those skilled in the art will recognize that the quantity, type, and arrangement of heating elements in the hot air introduction system can depend on the system configuration and the desired temperature of the air exiting the hot air introduction system.

[0026] The hot air introduction system may also include a fan 122 that introduces air from the hot air introduction system into the TAD system. The fan 122 may be located upstream (in terms of airflow) of any heating elements in the hot air introduction system, between heating elements in the hot air introduction system (as shown), or downstream (in terms of airflow) of any heating elements in the hot air introduction system.

[0027] In one example, the air entering the hot air introduction system can be pure ambient air received from the surroundings of the hot air introduction system. This can be accomplished by closing damper 130 and opening damper 140. In another example, the hot air introduction system The air entering the hot air intake system may be purely cooled air exiting the TAD system, possibly passing through exhaust fan 114, before entering the hot air intake system. This may be accomplished by closing damper 140 and opening damper 130. In a further example, the air entering the hot air intake system may be a combination of ambient air surrounding the hot air intake system and cooled air exiting the TAD system. This may be accomplished by opening the various dampers (130 / 140). The ratio of the mixed ambient air and cooled air entering the air intake system may depend on various factors, including system configuration (e.g., the amount each damper is opened or closed), air velocity, the desired temperature of the air exiting the hot air intake system, and other considerations.

[0028] The TAD 100, the main fan 108, the air heater 110, the mixer 112, and the ducting connecting these components may form a first air flow. The heating elements of the hot air introduction system together and the fan 122 may create a second air flow that is different from the first air flow.

[0029] Heated air generated by the heating elements of the hot air introduction system may be introduced into the first air stream of the TAD system (using fan 122 and opening dampers 126 / 134). This heated air generated by the hot air introduction system may be introduced into the TAD system air stream at various locations based on system configuration and requirements. For example, this heated air generated by the hot air introduction system may be introduced into the TAD system air stream between main fan 108 and air heater 110 (as shown), between air heater 110 and mixer 112, or at another desired location.

[0030] FIG. 2 illustrates two exemplary configurations of TAD systems equipped with hot air introduction systems. The first TAD system includes a TAD 100 including a perforated cylinder 104 at least partially enclosed by a hood 106, at least one main fan 108, at least one air heater 110, and at least one mixer 112. The second TAD system includes a TAD 200 including a perforated cylinder 204 at least partially enclosed by a hood 202, at least one main fan 208, at least one air heater 210, and at least one mixer 212. While only a single main fan 208, a single air heater 210, and a single mixer 212 are depicted, those skilled in the art will recognize that the TAD system may include multiple main fans 208 and / or multiple air heaters 210 and / or multiple mixers 212. The first TAD 100 and second TAD 200 dry articles as described above with respect to FIG. 1.

[0031] 2, like that of FIG. 1, is configured to recirculate a portion of the cooling air exiting the TAD 100 back into the TAD 100. Alternatively, a portion of the cooling air exiting the TAD 100 may be exhausted from the TAD system. Such exhaust air may be drawn into the hot air introduction system by an exhaust fan 114.

[0032] The same is true for TAD 200 in the sense that some air exiting the TAD 200 may be recirculated back into the TAD 200 (after being recirculated through main fan 208, air heater 210, and mixer 212) and some cooled air may be drawn into the hot air intake system by exhaust fan 206. In one example, exhaust fan 206 draws air from TAD 200 into an air stream located between exhaust fan 114 and air-to-glycol heat exchanger 116 and into the hot air intake system.

[0033] The system is configured such that the heated air exiting the hot air introduction system is The dampers 134, 214, 126 may be configured to allow flow into both TADs (100 / 200) (e.g., when dampers 134, 214, 126 are open and dampers 142 are closed), or to allow flow into one TAD (100 / 200) (e.g., when dampers 134, 214 are open and dampers 126, 142 are closed, when dampers 126, 134 are open and dampers 214, 142 are closed, etc.), or to allow flow into neither TAD (100 / 200) (e.g., when at least dampers 126, 214 are closed and damper 142 is open). The decision on how to route the heated air exiting the hot air intake system may depend on maintenance considerations, the desired temperature of the air being injected into the TAD (e.g., some items may be effectively dried at lower temperatures than others, eliminating the need to introduce heated air from the hot air intake system into the TAD air stream in such applications), and other considerations.

[0034] 3 illustrates the process performed by a single TAD system with a hot air introduction system. Heated air at a desired temperature is introduced into the hood 106 of the TAD 100, and the heated air at the desired temperature dries the items on the perforated cylinder 104, resulting in cooled air (302).

[0035] At least one heating element (e.g., glycol-air heat exchanger 118 and / or electric heater 120) of the hot air introduction system generates first heated air (304) from ambient air, some or all of the cooled air discharged from TAD 100, or a combination of ambient air and some or all of the cooled air discharged from TAD 100.

[0036] The hot air introduction system introduces the first heated air into the air stream of the TAD system. In one example, the first heated air is combined with at least a portion of the cooled air exiting the TAD 100 to create mixed air (306). In this embodiment, the air heater 110 heats the mixed air by combustion to create second heated air (308). The second heated air is then mixed by the action of a mixer 112 to create the heated air at the desired temperature used to dry articles (310).

[0037] The above process described with respect to Figure 3 may be performed by the two TAD systems shown in Figure 2. Also, although the steps of the method are described above in a particular order, one skilled in the art will appreciate that these steps may be performed in a different order without departing from this disclosure. It will be appreciated that various steps may be performed and / or some of these steps may be deleted or omitted.

[0038] Because the hot air introduction system is physically connected to at least one TAD system, flammable gases may enter the hot air introduction system while the at least one TAD system is operating. Therefore, a pre-ignition purge in accordance with NFPA-86 may be performed to evacuate four or more air volumes before starting the hot air introduction system. The at least one TAD system may be modified to ensure that the pre-ignition purge includes an additional interlock to ensure that no flammable gases are present in the hot air introduction system that could enter the at least one TAD system. The at least one TAD system and the hot air introduction system may be completely isolated by a dual block / bleed configuration using isolation dampers and bleed-off dampers.

[0039] The pre-ignition purge of the hot air intake system can be controlled by a dedicated hot air intake control system or by the factory's distributed control system (DCS). It is ensured that the hot air intake system is isolated from the at least one TAD system, all hot air intake piping is purged, ambient air is available to enter the hot air intake system, and the airflow for the pre-ignition purge is measured and verified. The air in the hot air intake system during the pre-ignition purge can be driven by a fan 122, and the airflow can be verified using a flow meter.

[0040] After the pre-ignition purge is complete and the at least one TAD system is operational and in a steady state condition, the hot air intake system may be started. To turn on the hot air intake system, all bleed-off dampers (e.g., 128 / 132, 216 / 220, etc., depending on the system configuration) of the hot air intake system may be closed to establish a single through-flow of air from the glycol-to-air heat exchanger 118 to the divert stack. Once this single through-flow is established, the electric heater 120 may be started until desired operation is achieved, thereby maintaining a constant (or relatively constant) temperature of the air exiting the electric heater 120 (and the hot air intake system, for that matter).

[0041] A damper (126, 214, depending on the system configuration) located at the connection between the piping of the hot air introduction system and the piping of the at least one TAD system may be opened to allow heated air to be introduced from the hot air introduction system into the airflow of the at least one TAD system. Simultaneously (or nearly simultaneously), at least one damper 142 of the diversion chimney of the hot air introduction system may be closed. As the heated air from the hot air introduction system is introduced into the airflow of the at least one TAD system, cooled air (e.g., exhaust air) of the at least one TAD system may be introduced into the hot air introduction system, thereby recovering exhaust energy of the at least one TAD system.

[0042] The hot air induction system is highly variable in that it allows variable combinations of ambient air and cooling air from at least one TAD system to enter the at least one TAD system. For example, in a two TAD system configuration, at least one damper may be open to allow only cooling air from a first TAD to enter the hot air induction system, at least one damper may be open to allow only cooling air from a second TAD to enter the hot air induction system, or at least one damper may be open to allow cooling air from both TADs to enter the hot air induction system. When the dampers are opened to allow cooling air from both TADs to enter the hot air introduction system, the dampers may be opened to allow more cooling air from a first TAD to enter the hot air introduction system than the cooling air from a second TAD, or to allow more cooling air from a second TAD to enter the hot air introduction system than the cooling air from the first TAD, or to allow equal amounts of cooling air from the first TAD and the second TAD to enter the hot air introduction system. The cooling air from the at least one TAD system may be flowed into the hot air introduction system downstream of glycol-to-air heat exchanger 118 but upstream of electric heater 120 relative to the air flow through the hot air introduction system. More preferably, the cooling air of the at least one TAD system may be introduced into the hot air intake system downstream of the glycol-air heat exchanger 118 relative to the hot air intake system air flow, but upstream of the electric heater 120 and the fan 122.

[0043] When the air from the hot air intake system is introduced into the air flow of the at least one TAD system, the temperature of the air in the at least one hood (106 / 202) can be adjusted to a desired temperature (e.g., the hot air intake system air) by adjusting the heating provided by the at least one air heater (110 / 210) and the speed of the at least one main fan (108 / 208). The at least one hood (106 / 202) may be maintained at a temperature equal to the temperature present in the at least one hood (106 / 202) prior to the introduction of air from the hot air intake system. This means that the introduction of heated air from the hot air intake system may reduce the amount of heating that must be provided by the at least one air heater (110 / 210). In embodiments where the at least one air heater (110 / 210) is powered by burning fossil fuels, this configuration may reduce the use of fossil fuels.

[0044] TAD systems can create stock-off situations where items to be dried (and / or already dried) are rapidly taken off the TAD system. It is important to quickly reduce the temperature of the air entering the hood of an AD system to a safe limit to prevent thermal damage to the TAD fabric, which is the fabric used to transport the items being dried (and / or already dried) within the system.

[0045] When the TAD system issues a stock-off signal, a TAD control system may close at least one damper (126, 214, depending on the system configuration) in the hot air intake system and open at least one damper 142 in the diversion chimney, thereby managing the temperature of the hot air intake system air and the load on the electric heater 120, which change during a sudden stock-off condition. When a stock-on signal is initiated and the TAD system indicates a steady state, air from the hot air intake system may be introduced into the TAD system (e.g., by opening at least one damper (128 / 214) and closing at least one damper 142 in the diversion chimney).

[0046] When a machine emergency stop (e-stop) command is received, components of the hot air intake system may be forced into a safe state. 20, and / or stopping fan 122, and / or closing all isolation dampers (e.g., 126 / 130 / 134 / 136 / 214 / 218, etc.) in the air induction system, and / or opening at least one damper 142 in the diversion chimney, and / or opening all bleed-off dampers (e.g., 128 / 132 / 216 / 220, etc.) in the hot air induction system. This damper configuration ensures that there is sufficient natural draft in the hot air induction system to prevent overheating of electric heater 120.

[0047] The hot air introduction system may be shut down independently of the at least one TAD system. Shutting down the hot air introduction system may include opening at least one damper 142 of the diversion chimney, closing all isolation dampers (e.g., 126 / 130 / 134 / 136 / 214 / 218, etc.) of the hot air introduction system, and / or opening all bleed-off dampers (e.g., 128 / 132 / 216 / 220, etc.) of the hot air introduction system, and / or gradually reducing power to electric heater 120 (e.g., according to a programmed ramp). The speed of fan 122 may also be gradually reduced (e.g., ramped) until fan 122 stops.

[0048] While the present disclosure has been described in detail with specific embodiments, it is evident that numerous alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore intended in the appended claims to embrace all such alternatives, modifications, and variations as fall within the true spirit and scope of the present disclosure.

Claims

1. 1. A system for drying or adhering an article, comprising: a combustion heater configured to generate a first heated air; a mixing element acting on the first heated air to produce second heated air at a desired temperature; a hood that receives the second heated air; and A perforated cylinder surrounded by the hood through which cooling air flows out a first group of components that generate a first air flow, the first group including: at least one heating element configured to generate a third heated air; and at least one fan in fluid communication with the at least one heating element for introducing the third heated air into the first air stream; a second set of components for generating a second air flow, including: A system comprising:

2. 10. The system of claim 1, wherein the air flowing through the at least one heating element is ambient air.

3. 10. The system of claim 1, wherein the air flowing through the at least one heating element is at least a minor portion of the cooling air.

4. 4. The system of claim 3, wherein ambient air passes through a glycol-to-air heat exchanger of the at least one heating element.

5. 10. The system of claim 1, wherein the air flowing into the at least one heating element is a combination of ambient air and at least a minor portion of the cooling air.

6. 10. The system of claim 1 further comprising: a third set of components for generating a third air flow, the third set including a second combustion heater configured to generate a fourth heated air, a second mixing element acting on the fourth heated air to generate a fifth heated air at a desired temperature, a second hood receiving the fifth heated air, and a second perforated cylinder surrounded by the second hood and outputting a second cooling air; A system comprising:

7. 7. The system of claim 6, wherein the air flowing through the at least one heating element is a combination of at least a portion of the cooling air and at least a portion of the second cooling air.

8. 5. The system of claim 4, wherein at least a portion of the cooling air is used to heat glycol in an air-to-glycol heat exchanger, and the heated glycol is supplied to the coil of the glycol-to-air heat exchanger.

9. 2. The system of claim 1, wherein the second group of components further includes a glycol-air heat exchanger that generates intermediate heated air, and an electric heater that acts on the intermediate heated air to generate the third heated air.

10. 10. The system of claim 1, wherein introducing the second heated air into the first air stream reduces the amount of combustion required by the fired heater.

11. 2. The system of claim 1, wherein the fired heater acts on the third heated air and at least a portion of the cooling air to produce the first heated air.

12. 2. The system of claim 1, wherein the mixing element acts on the first heated air and the third heated air to produce the second heated air at the desired temperature.

13. 1. A method for drying or adhering an article, comprising: generating a first air flow by generating cooled air, generating first heated air using at least a first heating element, mixing the first heated air to generate second heated air at a desired temperature, and exposing the second heated air to the article to generate the cooled air; generating a third heated air stream using at least a second heating element and introducing the third heated air stream into the first air stream to generate a second air stream; A method comprising:

14. The method of claim 13 further comprising: flowing ambient air through the at least second heating element; A method comprising:

15. The method of claim 13 further comprising: directing at least a portion of the cooling air through the at least second heating element; A method comprising:

16. The method of claim 13 further comprising: passing ambient air through a glycol-to-air heat exchanger included in the at least second heating element to produce a fourth heated air; A method comprising:

17. The method of claim 13 further comprising: flowing a combination of ambient air and at least a portion of the cooling air through the at least second heating element; A method comprising:

18. The method of claim 13 further comprising: generating a third air stream by generating a second cooled air, generating a fourth heated air using at least a third heating element, mixing the fourth heated air to generate a fifth heated air at a desired temperature, and exposing the fifth heated air to a second item to generate the second cooled air; A method comprising:

19. 20. The method of claim 18 further comprising: flowing a combination of at least a portion of the cooling air and at least a portion of the second cooling air through the at least a second heating element; A method comprising:

20. 17. The method of claim 16 further comprising: At least a portion of the cooling air is used to cool the glycol in the air-glycol heat exchanger. heating the mixture; supplying the heated glycol to a coil of the glycol-to-air heat exchanger; A method comprising:

21. The method of claim 13 further comprising: passing ambient air through a glycol-to-air heat exchanger to produce intermediate heated air; passing the intermediate heated air through an electric heater to generate the third heated air; A method comprising:

22. 14. The method of claim 13, wherein introducing the third heated air into the first air stream reduces the amount of combustion required to be carried by the at least first heating element.

23. The method of claim 13 further comprising: combining the third heated air with at least a portion of the cooled air to form mixed air; directing the mixed air into the at least a first heating element; A method comprising:

24. The method of claim 13 further comprising: mixing the first heated air with the third heated air to generate the second heated air at the desired temperature; A method comprising:

Images