WO2017125112A1 - Dryer for preparation of industrial use aggregate material - Google Patents

Dryer for preparation of industrial use aggregate material

Info

Publication number
WO2017125112A1
WO2017125112A1 PCT/DK2017/050010 DK2017050010W WO2017125112A1 WO 2017125112 A1 WO2017125112 A1 WO 2017125112A1 DK 2017050010 W DK2017050010 W DK 2017050010W WO 2017125112 A1 WO2017125112 A1 WO 2017125112A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
material
heating
dryer
aggregate
heat
Prior art date
Application number
PCT/DK2017/050010
Other languages
French (fr)
Other versions
WO2017125112A9 (en )
Inventor
Michael Gereon HAAS
Martin Raaby SKOU
René AGERHOLM
Original Assignee
Preheacon Aps
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • EFIXED CONSTRUCTIONS
    • E01CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01CCONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C19/00Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving
    • E01C19/02Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving for preparing the materials
    • E01C19/10Apparatus or plants for premixing or precoating aggregate or fillers with non-hydraulic binders, e.g. with bitumen, with resins, i.e. producing mixtures or coating aggregates otherwise than by penetrating or surface dressing; Apparatus for premixing non-hydraulic mixtures prior to placing or for reconditioning salvaged non-hydraulic compositions
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B11/00Machines or apparatus for drying solid materials or objects with movement which is non-progressive
    • F26B11/02Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles
    • F26B11/028Arrangements for the supply or exhaust of gaseous drying medium for direct heat transfer, e.g. perforated tubes, annular passages, burner arrangements, dust separation, combined direct and indirect heating
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B11/00Machines or apparatus for drying solid materials or objects with movement which is non-progressive
    • F26B11/02Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles
    • F26B11/04Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis
    • F26B11/0436Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis comprising multiple stages, e.g. multiple rotating drums subsequently receiving the material to be dried; Provisions for heat recuperation

Abstract

A dryer (10) for preparation of industrial use aggregate material, the dryer comprising a chamber, a dryer material infeed (100), a dryer material outfeed (1 10) and with a material flow direction from the infeed to the outfeed and at least one exhaust outlet (120), a first heat source ( 130) and a second heat source ( 140) so that the single chamber (150) of the dryer has at least two heating zones (230, 240). An industrial plant, an asphalt plant and a wood processing plant using such a dryer is also disclosed.

Description

Dryer for preparation of industrial use aggregate material

Field of the Invention

The present invention relates to a dryer for preparation of moist industrial use aggre- gate material. The invention concerns a dryer comprising a chamber, a dryer material infeed (infeed), a dryer material outfeed (outfeed) and with a material flow direction from the infeed to the outfeed and at least one exhaust outlet.

Background of the Invention

Aggregate material for industrial use is generally stockpiled uncovered until they are needed and may be exposed to ambient moist atmosphere, rain and snow. The moisture content in aggregate material may vary but can often be at a high level.

For a wide range of industrial productions the aggregate material has to be heated and dried to a lower moisture level to be used in the production. Preparation of the moist aggregate material for industrial use may therefore often involve a heating and drying process of the moist aggregate material through evaporation of the water contained in the materials. Drying systems for preparing aggregate material for industrial use typically comprise a single chamber and a single heating source for heating and drying the aggregate material. These dryers often comprise drum dryers configured with parallel-flow drums or counter-flow drums which describes that the heating direction is substantially parallel and in the same direction as the material flow direction in the dryer-chamber for parallel-flow drums or that the heating direction is substantially parallel but in the counter direction of the material flow direction in the dryer-chamber for counter-flow drums.

Using a single-chamber single-heating dryer may often involve a high temperature of the heat source with the risk of burning or decomposing the aggregate material during the heating and drying process. This is due to the fact that the evaporation of the contained water typically comprises an act of heating the aggregate material to a point well above water's boiling point to heat and dry the aggregate material sufficiently for further use.

Industrial products where a high temperature within the dryer may pose various risks are within wood processing for the furniture industry. Here there is a risk of damaging the wood at high temperatures especially as the wood is dried out through the process. Another industry is the asphalt industry where materials are to be heated to a temperature typically in the range of 130-160°C for further use in the production. Especially, the use of recycled asphalt pavement (RAP) has typically required even higher tem- peratures with the risk of decomposing the bitumen and developing high amounts of blue smoke.

A lower process temperature in the drying and heating phase is also interesting in view of a reduction in energy consumption. Another aspect in the drying and heating phase with a view to reducing energy consumption could be to optimize the regulation of the process temperatures.

Drying systems for industrial use aggregate material which reduces the output temperature of the material from the dryer have been suggested especially within the asphalt industry. US2007/0172313 discloses a heating system for drying and heating worn road coating materials using two separate modules each module comprising at least one heating source. US5201839 discloses a drum mixer for hot mix asphalt (HMA) production with a second heat source wherein the aggregate material is heated and dried using two rotary drums each provided with a heat source and interconnected by a conveyor belt. Both systems are suggested for producing asphalt partly comprising RAP. Both systems use two separate chambers and thus require additional space compared to conventional comparable dryers.

Object of the Invention

It is an objective of this invention to overcome one or more of the aforementioned shortcomings of the prior art. Description of the Invention

The aforementioned aspects may be achieved by a dryer for preparation of industrial use aggregate material. The dryer comprises a dryer material infeed (infeed), a dryer material outfeed (outfeed) with a flow direction from the infeed to the outfeed and at least one exhaust outlet. The dryer comprises a single chamber configured with at least a first heat source and a second heat source in respective first and second heating zones. The infeed is in the first heating zone and the outfeed is in the second heating zone. The dryer further comprises a first heat source with a first heating direction and is configured to heat the material to a first temperature in the first heating zone. Furthermore, the dryer comprises a second heat source with a second heating direction and is configured to heat the material from a first temperature to a second temperature in the second heating zone. Thus, the single chamber has at least two heating zones with two distinct heat sources and aggregate material flow in the flow direction.

The suggested dryer is a dual-zone dryer. It may also be referred to as a multiple- zone dryer.

The flow direction describes the resulting flow direction of the material which is from dryer material infeed to dryer material outfeed. This means that even if the material is rotated within the dryer, the flow direction is still from infeed to out- feed.

A heat source with a heat direction may be understood as a heat source which may heat in a main direction. The heat source may comprise means to direct the heat in the main direction. These means may be a part of the construction of the heat source or may consist of an additional construction incorporated in the chamber construction. A person skilled in the art will know which possible means may be implemented and how these may be implemented to achieve a heat source with a heat direction. Aggregate material for industrial use often comprises a high humidity aggregate material or moist aggregate material when delivered to, or after storage at the industrial plant. The disclosed dryer may be used for moist aggregate material to be heated and dried before further processing can take place, or the dryer may be used for dry aggregate material only to be heated before further processing in the plant. Dried material in this context may cover any degree of moisture content of the material but the moisture content must be decreased during the heating process.

The heating and drying process is generally termed heating process in the follow- ing.

Due to the multiple heating sources and the two heating zones the effect of this embodiment is that the temperature in the chamber may be kept at stable temperatures. The advantage of this is a reduced risk of burning or decomposing the aggregate mate- rial during the heating and drying.

By a stable temperature is meant that the variation in temperature throughout the chamber from infeed to outfeed may be reduced compared to a single-chamber-single- heater dryer. Fluctuations or deviations will still occur along the chamber. But due to a first and a second heating source respectively in the first and second heating zone, the energy output to heat the material is distributed along the chamber and thus lower maximum temperatures may be employed.

A further advantage of a stable temperature in the chamber may be a reduction of en- ergy consumption due to the fact that the heat transmission is time-dependent. Thus a high temperature difference between the heat from the burner and the material may not increase the heat transfer comparable to the heat transfer occurring at a lower temperature difference when considering the energy output from the burner. Yet another effect of this embodiment may be that the aggregate material may be heated more aggressively in the first heating zone than in the second heating zone. The advantage of this may be that the material may be heated and dried faster compared to single-chamber-single-heater dryer. The degree of how aggressively the aggregate material may be heated in the first heating zone may depend on the type of material and the moisture content. But precisely because of the moisture content of the aggregate material, the aggregate material may be heated more aggressively without risking burning or decomposing the aggregate material during the heating and drying. Aggressively heating may refer to that heat energy may transferred at a higher rate, over a longer period or both compared with the transfer rate typically used in a single- chamber-single-heater dryer.

Thus, heat energy may be transferred at a higher rate because the latent heat cools the material due to evaporation, compared with the transfer rate typically used in a single chamber-single-heater dryer.

Aggregate material may comprise the materials or part of the materials to be used for the production. This may include virgin raw materials or recycled materials or a combination of both. The aggregate material may include construction materials like stone, rock, gravel, sand, minerals. Also included may be raw materials like wood, clay, plant parts, plastic or other materials for industrial use which enter a production process requiring drying and heating of the aggregate material. The industrial use may be in the construction industry for producing concrete, cement, asphalt, or refining of construction materials. Also included but not limited to may be the timber industry or refineries of wood or wooden chips, plastic industry or productions making plastic products, and productions refining plant parts or productions comprising plant fibres as part of the aggregate material.

Recycled materials are becoming more and more interesting to include as aggregate material. As one example, but not limited to this, is the construction industry which has a high interest in recycling asphalt pavement. The heater sources may be dependent on the industry and aggregate material. The heater may comprise a direct combustion burner, an indirect combustion burner, other burner types, other heat sources or a combination of these. The efficiency of combustion burners for example may be reduced due to a large amount of air in the dryer. In another embodiment the dual-zone dryer may have a first heating direction and a second heating direction substantially parallel to the flow direction.

In a further embodiment of the dual-zone dryer at least one of the first heating direction or the second heating direction is substantially counter-directional to the flow direction.

Effects of these two embodiments are that the dual-zone dryer may be configured for either parallel-flow heating, counter-flow heating or a combination of parallel- flow and counter-flow heating.

One advantage of the above-mentioned embodiments is that the parallel-flow and counter-flow heating is known from conventional industrial dryers. Due to the substantially parallel alignment of the heating direction and the flow direction, the heating sources may be arranged substantially parallel with the chamber. Thus, the chamber may comprise rotational means constructed to be rotated around the flow direction axis without obstructing the heat path through the chamber. The dryer may be constructed with the heat sources arranged independently of the rotation or arranged in a construction that rotates along with the rotational means. Fur- thermore, the chamber may comprise other transportation means than rotational means without obstructing the heat path through the chamber which transportation means may prolong the transport path through the chamber from infeed to out- feed. The above-mentioned effect of parallel heating has the further advantage that the dryer may be constructed using a conventionally known technology and constructed with convention geometry of industrial dryers.

A person skilled in the art will acknowledge the above-mentioned advantage of lower working temperatures of the heat sources and the stable temperature throughout the chamber achieved by providing a parallel heating single-chamber-dryer with a second heat zone comprising at least one second heat source compared to conventional parallel heating single-chamber-dryers with a single heat source. Furthermore, a skilled person will know that the dual-zone dryer may be substantially comparable with the construction of conventional dryers and thus the technological knowledge within dryer construction and industrial plant construction comprising dryers may be exploited for constructing and applying the dual-zone dryer.

In one embodiment, the dryer may comprise sensor means configured to measure environmental conditions in the chamber. In another embodiment, the chamber may comprise regulation means configured to regulate the heat source output of one or more heat sources, material load or a combination of heat source output and material load. In yet another embodiment, the chamber may comprise both sensor means and regulation means as describe above.

The effect of employing sensor means is measurement or monitoring of the environmental conditions in the chamber during the heating and drying process. The parameters to be measured or monitored may comprise heat source temperature, chamber temperature, humidity in the chamber, material temperature, moisture content in the material, exhaust composition, or the like. The measurements may be effected as direct or indirect measurements. This is advantageous in regard to verifying the conditions of the materials during the heating and drying process. Another advantage may be to verify the material conditions when entering the further production. Yet another advantage is that an alarm may be utilized for upper or lower limits of a given parameter. The effect of employing regulation means is regulation of the heating and drying condition. The parameters to be regulated may comprise the heat source output and the material load. Material load encompasses material quantity feed to the chamber, the speed by which material is fed to the chamber or the like. This is advantageous in regard to obtaining the right conditions in the heating and drying process by adjusting the material load to the heat output or by adjusting the heat output to the material load and to the material composition if the material composition changes from batch to batch. A change in material composition may be a change in moisture content of the aggregate material, a change in the percent- age or virgin aggregate material to recycle material or different qualities of products requiring different material content or a change in the percentage of the different materials. A further advantage of employing regulation means is to optimize the energy consumption by adjusting the material load to the heat output or vice versa as described above.

Combining sensor means and regulation means has the effect that a feed-back or feed-forward regulation may be implemented. This is advantageous in regard to employing a continuous regulation of the process to optimize the process both in regard to energy consumption and material conditions.

In one embodiment the dryer chamber comprises at least one additional infeed arranged between the dryer material infeed and the dryer material outfeed.

The effect of this embodiment is that additional ingredients may be fed to the chamber and to the aggregate material in the dryer during the heating process. One advantage is that additional material may be added later in the process for example at a given temperature or moisture content of the aggregate material already in the chamber, or the added material may only be heated for a shorter period of time than the process time from dryer material infeed to dryer material out- feed. Depending on the function of the chamber the added material may mixed with aggregate material already in the chamber.

The additional infeed may be for solid materials, fluids or material in other states and thus the additional infeed may comprise mechanical devices such as nozzles, jets, scoop openings or the like. In another embodiment the dual-zone dryer may comprise a rotary drum configured to agitate or lift aggregate material during transport in the flow direction. The lifting or agitation of aggregate material in the drum may be achieved by lifting flights, paddles or shovels within the rotary drum. The effect of this embodiment is that the heat is led through the rotary drum filling the inside of the drum while the aggregate material is agitated or lifted causing a large surface of the aggregate material to be exposed to the heat. One advantage of this embodiment is that a larger surface may be obtained for heat transfer, and thus a larger amount of the heat energy may be utilized. This embodiment is also advantageous in relation to drying the aggregate material during the process as the water contained in the cavities within the aggregate material may be more easily accessible for the heat due to the agitation or lifting.

Another advantage is that the aggregate material may be mixed during the heating process. This may also be advantageous if additional feeds are employed and thus material added during the process may by mixed with aggregate material already in the chamber.

Furthermore, as previously described, a person skilled in the art will know that the dual-zone dryer may be substantially comparable with the construction of conventional dryers and thus the technological knowledge within drum dryer construction and industrial plant construction comprising drum dryers may be exploited for construct- ing and applying this embodiment of the dual-zone dryer.

In one embodiment the dryer, may be comprised in an industrial plant comprising one or more production devices or storage means for prepared industrial use aggregate material. This embodiment comprises interface means between the dryer and the production device(s) or storage means for the prepared aggregate material.

In another embodiment, the dryer may be comprised in an asphalt plant comprising one or more production devices or storage means for prepared industrial use aggregate material. This embodiment comprises interface means between the dryer and the production device(s) or storage means for the prepared aggregate material.

In yet another embodiment, the dryer may be comprised in a wood processing plant comprising one or more production devices or storage means for prepared industrial use aggregate material. This embodiment comprises interface means between the dryer and the production device(s) or storage means for the prepared aggregate material.

The scope of the invention is by no means limited to the above-mentioned three em- bodiments. Other embodiments may include plants for production of fabrics using plant fibres, plants preparing plant fibres for other uses, plants using plastic clay for the construction industry, industrial plants producing plastic parts or preparing plastic, which further embodiments by no means are exhaustive. Rather a person skilled in the art facing similar problems in different fields will be able to appreciate the disclosed workings and implement those and thereby make use of the invention in other fields than those here recited. Industrial plant and industrial use should therefore be conceived as a general term encompassing uses and plants with large scale production or aiming at batch production. The effect of the above-mentioned embodiments is that the dryer may be used in various industries with the advantage that the dryer may be implemented in existing or new plants by establishing the relevant interface means.

Particularly in the construction industry, attempts have been made to improve energy and production efficiency. In conventional plants for making asphaltic concrete paving materials, a stone raw material, recycled raw material and bitumen are mixed, dried and heated to produce the final product. The raw materials and recycled materials typically have a moisture content of 5% and, depending on the ambient conditions, the energy consumption in the heating and drying process may reach levels around lOO kWh/ton.

Conventional direct-fired prior art drum hot mix asphalt (HMA) plants often utilize a mixture of virgin aggregate material and recycled asphalt products (RAP). Increasing the percentage of RAP in the end product is especially interesting. However, RAP contains bitumen which decomposes at high temperatures well before any of the other materials are damaged. To recover RAP in the production, the virgin aggregate material is conventionally heated to a point far above the boiling point of water during the asphalt production process. The increased temperature of the virgin aggregate material is required because the virgin aggregate material must comprise sufficient heat energy for heating and drying the RAP in a later mixing process. This heating to above the vaporization point in the drying and heating process consumes a large amount of energy. The effect of this embodiment, if for example used in HMA plants, is that the RAP may be added already in the dryer due to the lower temperature in the dual -zone dryer according to the invention by which decomposition of the bitumen is reduced. Hereby is achieved the advantage of reducing the energy consumption in the heating and drying process, as the virgin aggregate material is not transported from the dryer to the mixer at a high temperature with a high heal loss as a consequence.

A further advantage is that an increased content of RAP can be achieved in the final product due to the heating and drying of both the virgin aggregate material and RAP in the dryer. Thus, the share of virgin aggregate material and RAP is not dependent on that the virgin aggregate material carrying excess heat energy for heating and drying the RAP in a later mixing process.

In one embodiment, the dual-zone dryer may be comprised in an asphalt plant. In this embodiment, the dryer comprises a rotary drum dryer, a set of ring infeeds, a first heating source with the first zone heating direction in the first direction, and a second heating source with the second zone heating direction being counter- directional to the first direction. Furthermore the first temperature in the dryer may be in the range between water's boiling point and a temperature at which bitumen starts to degrade so that development of blue smoke from the asphalt pro- duclion is reduced.

As previously described, one effect of this embodiment is that the RAP may be added already in the dryer due to the lower temperature in the dual-zone dryer according to the invention by which reduced decomposition of the bitumen is achieved and consequently less blue smoke is developed. Thereby is achieved the advantage of reducing the energy consumption in the heating and drying process as the virgin aggregate material is not transported from the dryer to the mixer at a high temperature with a high heat loss as a consequence. A further advantage is that an increased content of RAP in the final product may be achieved due to the heating and drying of both the virgin aggregate material and RAP in the dryer. Thus, the share of virgin aggregate material and RAP is not dependent on the virgin aggregate material carrying excess heat energy for heating and drying the RAP in a later mixing process.

As previously described, another effect of this embodiment is that the dryer may be used in various industries with the advantage that the dryer may be implemented in existing or new plants by establishing the relevant interface means.

Yet another effect of this embodiment is that the heat is led through the rotary drum filling the inside of the drum while the aggregate material is agitated or lifted causing a large surface of the aggregate material to be exposed to the heat. One advantage of this embodiment is that a larger surface may be obtained for heat transfer, and thus a larger amount of the heat energy may be utilized. This embodiment is also advantageous in relation to drying the aggregate material during the process as the water contained in the cavities within the aggregate material may be more easily accessible for the heat due to the agitation or lifting. Another advantage is that the aggregate material may be mixed during the heating process. This may also be advantageous if additional feeds are employed and thus material added during the process may by mixed with aggregate material already in the chamber.

Furthermore, an effect of this embodiment is that additional ingredients may be fed to the chamber and to the aggregate material in the dryer during the heating process. A set of infeeds may comprise an empty set, a set of one (singleton), or a set of multiple infeeds. One advantage is that additional material may be added later in the process, for example at a given temperature or moisture content of the aggregate material already in the chamber, or the added material may only be heated for a shorter period of time than the process time from dryer material in- feed to dryer material outfeed. The material added through additional infeed may be mixed with the aggregate material already in the chamber. Furthermore, as previously described, a person skilled in the art will know that this embodiment of the dual-zone dryer may be substantially comparable with the construction of conventional drum dryers and thus the technological knowledge within drum dryer construction and industrial plant construction comprising drum dryers may be exploited for constructing and applying this embodiment of the dual-zone dryer.

An object of the invention may be achieved by a method of preparing industrial use aggregate material with a dual-zone dryer. The method comprises the acts of heating aggregate material in the dryer to a first temperature in the first heating zone using the first heal source, and heating the aggregate material in the dryer to a second temperature in the second heating zone using the second heat source. The acts constitute a continuous process in a single chamber. The first heating direction and second heating direction are substantially parallel to the flow direction. An effect of this method is to gain stable temperatures throughout the chamber. The advantage may be a reduced risk of burning or decomposing the aggregate material during the heating and drying process. A further advantage of a stable temperature in the chamber may be a reduction of energy consumption due to the heat transmission being time-dependent, as previously described.

An object of the invention may be achieved by a method of preparing industrial use aggregate material comprising the acts of regulating the heat source output of one or more heat sources or material load or a combination of heal source output and material load, or measuring environmental conditions inside the dryer. A further object of the invention may be achieved by a method of preparing industrial use aggregate material comprising the act of performing a regulation of the heat source output of one or more heat sources or material load or a combination of heat source output and material load based on input comprising measured environmental conditions inside the dryer.

One effect of this method is to measure or monitor the environmental conditions in the chamber during the heating and drying process. As previously described the measured or monitored parameters may comprise heat source temperature, cham- ber temperature, humidity in the chamber, material temperature, moisture content in the material, exhaust composition or the like.

This is advantageous in regard to verifying the conditions of the materials during the heating and drying process. Another advantage may be to verify the material conditions when entering the further production. Yet another advantage is that an alarm may be utilized if the measured parameter exceeds the limits for the process. Another effect of this method is to regulate the heating and drying condition. The parameters that may be regulated may comprise the heat source output and the material load. Material load encompasses material quantity feed to the chamber, the speed of which material is fed to the chamber or the like. This is advantageous in regard to obtaining the right conditions in the heating and drying process by adjusting the material load to the heat output or by adjusting the heat output to the material load and to the material composition if the material composition changes from batch to batch. Yet another advantage of this method is to optimize the energy consumption by adjusting the material load to the heat output or vice versa as described above.

By this method, regulation of the heat source output of one or more heat sources or material load, or a combination of heat source output and material load, may be performed based on input comprising measured environmental conditions inside the dryer. Thus one effect of this method is that a feed-back or feed-forward regulation may be performed.

This is advantageous for effecting continuous regulation of the process so as to optimize the process both in regard to energy consumption and material conditions. An object of the invention may be achieved by a method of preparing industrial use aggregate material comprising a further act of feeding aggregate material into the chamber through at least one additional infeed. The effect of this method is that additional ingredients may be fed to the chamber and to the aggregate material in the dryer during the heating process. One advantage is that additional material may be added later in the process, for example at a given temperature or moisture content of the aggregate material already in the chamber, or the added material may only be heated for a shorter period of time than the process time from dryer material infeed to dryer material outfeed. Depending on the function of the chamber, the added material may be mixed with aggregate material already in the chamber.

An object of the invention may be achieved by a method of providing an industrial plant with a dual-zone dryer for preparation of industrial use aggregate material. The method comprises the acts of providing an industrial plant and retrofitting the existing industrial plant with the dryer.

The effect of the above-mentioned embodiment is that the dryer may be used in vari- ous industries, and the dryer may be implemented in existing or new plants by retrofitting the dryer. The advantage is that the dryer may be retrofitted into existing plants with a single-chamber dryer with relevant interface means.

Another object of the invention may be achieved by a similar method of providing an industrial plant with a dual-zone dryer for preparation of industrial use aggregate material. This method comprises the acts of providing an industrial plant and retrofitting a single chamber of an existing dryer with a second heat source and a second heating zone. The first and second heat sources are arranged with the first heating direction and the second heating direction substantially parallel to the flow direction and with the first heating direction and the second heating direction substantially facing each other.

The effect of the above-mentioned embodiment is that the dryer, as in the previous method, may be used in various industries, and the dryer may be implemented in ex- isting or new plants by retrofitting the chamber of an existing single-chamber dryer with parallel heating. The existing single-chamber dryer may already be implemented in the plant, or the existing single-chamber dryer may be a dryer not yet implemented in the plant. The advantage of this method is that conventional single-chamber dryers may be retrofitted into a dual-zone dryer of an existing plant with relevant interface means between the second heating source and the chamber of the existing dryer.

An advantage of the above-mentioned method is that the parallel-flow and counter- flow heating is known from conventional industrial dryers. Thus, the chamber may be constructed for retrofitting a second heating source and heating zone to the chamber without obstructions to the heat path through the chamber of the first and the second heat source.

The effect of parallel heating has the further advantage that the dryer may be constructed using conventionally known technology and constructed with convention geometry of industrial dryers.

Furthermore, a skilled person will know that the dual-zone dryer may be substantially comparable with the construction of conventional dryers, and thus the technological knowledge within dryer construction and industrial plant construction comprising dry- ers may be exploited for retrofitting the dual-zone dryer to an existing plant.

A further object of the invention may be achieved by a method of preparing industrial use aggregate material by means of a dual-zone dryer. The method comprises the further act of heating and drying the moist aggregate material in the dryer in the first heating zone using the first heat source by heating the aggregate material to above the boiling point of the moisture contained in and to be removed from the aggregate material so that a phase transition of the moisture from liquid-phase to vapour-phase occurs. An effect of this method is that the aggregate material is dried in the first heating zone. The advantage is that a stable temperature at the boiling point is reached in the first zone. This reduces the risk of burning or decomposing the aggregate material in the first heating zone. Furthermore, the moisture content of the aggregate material is reduced as the material moves away from the first heat source which also reduces the risk of burning or decomposing the material. In the second heating zone the heat output from the second heat source is only used for heating the material and thus effective energy consumption may be achieved. A further object of the invention may be achieved by use of the dual-zone dryer in an industrial plant comprising acts of heating aggregate material in the dryer to a first temperature in the first heating zone using the first heat source, and heating the aggregate material in the dryer to a second temperature in the second heating zone using the second heat source. The acts constitute a continuous process in a single chamber. The first heating direction and second heating direction are substantially parallel to the flow direction. The use may further comprise the acts described in the methods above.

Further objects of the invention may be achieved by use of the dual-zone dryer in an asphalt plant or a wood processing plant comprising the above-mentioned acts.

The use of the invention is by no means limited to the above-mentioned embodiments. Other uses of the invention may include plants for production of fabrics using plant fibres, plants preparing plant fibres for other uses, plants using plastic clay for the construction industry, which further embodiments by no means are exhaustive. Rather a person skilled in the art facing similar problems in different fields will be able to appreciate the disclosed workings and implement those and thereby make use of the invention in other fields than those here recited. One effect is that the use of the dual-zone dryer may be implemented to existing productions or incorporated in new productions with the advantage that incorporating the use of a dual-zone dryer may require none or small changes in workflow and recipes used in a given production.

Description of the Drawing

Figure 1 illustrates one embodiment of the dryer comprising a single chamber and two heating sources. The chamber comprises two heating zones, and the material flow direction from dryer infeed to dryer outfeed is illustrated. The dryer is illustrated with a first and a second heating source. Figure 2 illustrates two embodiments of the dryer comprising a first and a second heating source. In fig. 2A, the heat sources face each other. In fig. 2B, the heat sources face in the same direction.

Figure 3 illustrates an embodiment of the dryer comprising a first and a second heating source facing each other where moist aggregate material is dried and heated in the first heating zone and further heated in the second zone. The temperature curve of the material in the first and second heat zone is illustrated.

Figure 4 illustrates one embodiment of the dryer comprising a rotary drum and a first and a second heating source facing each other.

Figure 5 illustrates one embodiment of the dryer comprising a rotary drum and a first and a second heating source facing each other. The illustrated heat sources are combustion burners with the hot gas stream shielded from the aggregate material.

Figure 6 illustrates two methods of preparing industrial use aggregate material. Figure 6 A illustrates one method comprising the acts of heating the materials in a first heating zone and in a second heating zone in a dual-zone dryer wherein the acts constitute a continuous process. Figure 6B illustrates another method wherein an act of heating and drying the material in the first heating zone is comprised. Furthermore, Figure 6B illustrates additional methods comprising acts such as regulating or measuring parameters in connection with preparing industrial use aggregate material and acts of feeding additional material to the chamber during the heating process.

Figure 7 illustrates a method of retrofitting an industrial plant with a dual-zone- dryer.

Detailed Description of the Invention

Figure imgf000019_0001
Figure imgf000020_0001
Figure imgf000021_0001

One embodiment of the dryer 10 illustrated in fig. 1 comprises a single chamber 150 and two heating sources 30, a first heating source 130 and a second heating source 140. The chamber 150 comprises a first heating zone 230 and a second heating zone 240. The material flow direction 250 runs in the direction from dryer infeed 100 to dryer outfeed 110. Aggregate material 20 is fed to the chamber 150 through the dryer infeed 100 and prepared aggregate material 22 is discharged from the chamber 150 through the dryer outfeed 110. The chamber in the illustrated embodiment further comprises an exhaust outlet 120 placed in the first heating zone 230 for exhaust comprising steam from the moist aggregate material 20 and other gasses or particles released during the heating process or the heating and drying process. The exhaust may be led to further processing which is not shown here but which may comprise decontamination acts, filtering processes, storage or other relevant process depending on the type of aggregate material .

Figure 2A illustrates one embodiment of the dryer 10 comprising a first and a second heat source 130,140 facing each other. The first heating direction 232 and second heating direction 242 are substantially parallel to the flow direction 250 but with the second heating direction 242 substantially counter-directional to the flow direction 250 and thus the heating of the material is counter-directional 270.

Figure 2B illustrates another embodiment of the dryer 10 comprising a first and a second heat source 130,140 facing the same direction. The first heating direction 232 and second heating direction 242 are substantially parallel and in the same direc- lion as the flow direction 250 and thus the heating of the material is parallel directional 260.

Figure 3 illustrates an embodiment of the dryer comprising a first and a second heat source 130,140 facing each other where moist aggregate material 20 is dried and heated in the first heating zone 230 and heated further in the second heating zone 240. The moist aggregate material 20 is fed to the chamber ISO through the dryer infeed 100, and prepared aggregate material 22 is discharged from the chamber ISO through the dryer outfeed 110. The material flow direction 250 runs in the direction from dryer infeed 100 to dryer outfeed 110. The temperature curve of the material vs. position in the chamber is illustrated by the dotted line in fig. 3. At infeed the temperature of the aggregate material 20 is below the boiling point temperature of the moisture (T_b) contained in and to be removed from the aggregate material. During transport through the first heating zone 230 in the flow direction 250 the aggregate material 20 is in the first part of the zone heated to T_b. After reaching T_b the temperature is substantially steady at T_b for a given time interval because a phase transition of the moisture from liquid-phase to vapour-phase occurs. This time-interval and length of transport of the material depend on the heat source output, moisture content, heat transmission in the material, material load, material type, size of raa- terial grains and the like. Due to the phase transition taking place the energy output from the heat source is primarily used for drying the material. And thus, as illustrated on the temperature curve in fig. 3, the material temperature is substantially steady during transport through a second part of the first heating zone 230. When the moisture content approaches zero, the energy output from the heat source primarily heats the material and thus the temperature increases above T_b to the first temperature 210 as the material is transported through the last part of the first heating zone 230. The material temperature continues to rise from the first temperature 210 to the second temperature 220 through the second heating zone 240 because the energy output from the second heat source 140 is primarily used for heating the material 20. The dried and heated material is then discharged from the chamber through the outfeed 110.

For this embodiment a specific example shows a calculated reduction in energy consumption of 1.3% compared to a single-heater single-chamber dryer. The cal- culaled example is for the asphalt industry using aggregate material 20 with 5% moisture content, a material load 370 of 100,000 kg h fed to the dryer 10, a material temperature at infeed of 12°C and 160°C at outfeed, and with an air surplus in the dryer. The material parameters used are: Enthalpy for evaporation 2662 kJ/kg, heat coefficient C_p for dry asphalt 1.98 kJ kg*K, heat coefficient C_p for wet asphalt 2.1 kJ/kg*K. Using a dual-zone dryer in which the efficiency is that 90% of the heat from the first heat source 130, an efficiency of 70% of the heat from the second heat source 140 is used for heating and drying the material, and the first temperature 210 of the material is set to 105°C, the total energy supply from the heaters are 14.2 MW. The total energy supplied is supplied as 10.1 MW from the first heat source 130 and 4.1 MW from the second heat source 140. A conventional single-heater single-chamber dryer with an efficiency of 78% should provide 15.3 MW. In the example, the dual-zone dryer comprises a heat source with lambda, λ=1.1 for the first heating zone 230 and a heat source with lambda, λ=4.5 for the second heating zone 240. For the conventional dryer, a heat source with lambda, λ=2.5 is used. Lambda is a value expressing the access air in the dryer. The amount of air may be regulated according to the combustion of the burner.

A person skilled in the art will know how to calculate the energy required for other material types, moisture content, temperatures, and use heat sources with other parameters. Furthermore, a person skilled in the art will appreciate the relevance of the parameters employed in the above example for the burners and the material.

Figure 4 illustrates one embodiment of the dryer 10 comprising a rotary drum 170 (not illustrated) and a first 130 and a second heating source 140 facing each other. The aggregate material 20 is fed to the chamber 150 through the dryer infeed 100 and enters the rotary drum 170 configured to agitate or lift the aggregate material 20 during transport in the flow direction 250. Thereby the aggregate material 20 is mixed and exposed to the heat energy from the heat sources 30 during transport through the chamber. The lifting or agitation of aggregate material in the drum may be achieved by lifting flights, paddles or shovels within the rotary drum 170. The prepared ag- gregate material 22 is discharged from the chamber ISO through the dryer outfeed 110.

Figure S illustrates one embodiment of the dryer comprising a rotary drum and a first 130 and a second heating source 140 facing each other. The illustrated heat sources are combustion burners with the hot gas stream shielded from the aggregate material. In this embodiment, the heat sources 30 extend a considerable way into the chamber and thus the respective heating zones. The aggregate material is fed to the chamber such that the material is heated due to indirect heating from the shielding pipe of the first heat source. The aggregate material lifted by the rotary drum is thus shielded from the direct heat of the combustion burners as the material falls from the upper part of the chamber to the lower part. In the subsequent part of the first heating zone where the temperature of the hot gas stream has decreased, the hot gas stream is no longer shielded, and thus the aggregate materiel 20 is directly heated by the hot gas stream. As the material 20 approaches the out- feed 110 in the second heating zone 240, the material heating goes from direct heating to indirect heating because the shielding of the second heat source 140 extends into the second heating zone 240 passing the outfeed and further into the chamber 150 in the direction of the first heating zone 230.

In figure 6 two methods 400 of preparing industrial use aggregate material are illustrated. Figure 6A illustrates one method 400 comprising the acts of heating 410 the material 20 in a first heating zone 230 and in a second heating zone 240 in a dryer 10 wherein the acts constitute a continuous process. Figure 6B illustrates another method 400 wherein an act of heating 410 and drying 480 the material in the first heating 230 zone is comprised. Furthermore, Figure 6B illustrates additional method acts such as regulating 420 on or measuring 430 of parameters in connection with preparing industrial use aggregate material and acts of feeding 450 additional material to the chamber 150 during the process of preparing industrial use aggregate material. Parameters to be regulated may comprise heater output 360, material load 370 or a combination of material load 370 and heater output 360. Regulation of the material load may also comprise material load feed to the chamber through additional infeed 160 (not illustrated). Figure 6B illustrates yet an additional method 400 comprising an act of performing 440 regulation of one or more heat source outputs 360, regulation of the material load 370 or regulation on a combination of heat source output 360 and material load 370 based on input comprising measured 430 environmental conditions 350 inside the chamber, so that a feed-back regulation on the process of preparing industrial use aggregate material is performed.

Figure 7 illustrates a method 400 of retrofitting 470 an existing industrial plant 50 with a multiple-zone-dryer 10. The method 400 comprises the acts of providing 460 an industrial plant 50 for whose production the preparation of industrial use aggregate material is relevant, and retrofitting 470 the existing industrial plant 50 with the dryer 10. Another method 400 may comprise the act of retrofitting 470 a single chamber 150 of an existing dryer 60 with a second heat source 140 and a second heating zone 240.

Claims

1. A dryer (10) for preparation of industrial use aggregate material (20) comprising a dryer material infeed (100), a dryer material outfeed (110) with a flow direction (250) from the infeed (100) to the outfeed (110) and at least one exhaust outlet (120) characterized in that the dryer (10) comprises
- a single chamber (150) configured with at least a first heat source (130) and a second heat source (140) in respective first and second heating zones (230,240) where the infeed (100) is in the first heating zone (230) and the outfeed (110) is in the second heating zone (240);
- the first heat source (130) with a first heating direction (232) and configured to heat the material to a first temperature (330) in the first heating zone (230); and
- the second heat source (140) with a second heating direction (242) and configured to heat the material from a first temperature (330) to a second temperature (340) in the second heating zone (240);
so that the single chamber (150) has at least two heating zones (230,240) with two distinct heat sources and aggregate material flow in the flow direction (250).
2. Dryer (10) according to claim 1 characterized in that the first heating direction (232) and second heating direction (242) are substantially parallel to the flow direction (250).
3. Dryer (10) according to any of the claims 1 or 2 characterized in that at least one of the first heating direction (232) or the second heating direction (242) is substan- tially counter-directional (270) to the flow direction (250).
4. Dryer (10) according to any of the preceding claims characterized in that the dryer (10) comprises
- sensor means (152) configured to measure environmental conditions (350) in the chamber (150)
- regulation means (154) configured to regulate the heat source output (360) of one or more heat sources (30) or material load (370) or a combination of heat source output (360) and material load (370);
- or sensor means (152) and regulation means (154).
5. Dryer (10) according to any of the preceding claims characterized in that the chamber (ISO) comprises at least one additional infeed (160) arranged between the dryer material infeed (100) and the dryer material outfeed (110).
6. Dryer (10) according to any of the preceding claims characterized in that the dryer (10) comprises a rotary drum (170) configured to agitate or lift aggregate material (20) during transport in the flow direction (250).
7. An industrial plant (40) comprising one or more production devices (42) or stor- age means (44) for prepared industrial use aggregate material (22), which plant (40) comprises a dryer (10) according to any of the claims 1 to 6 and interface means between the dryer (10) and the production device(s) (42) or storage means (44) for the prepared aggregate material (22).
8. An asphalt plant (40) comprising one or more production devices (42) or storage means (44) for prepared industrial use aggregate material (22), which plant (40) comprises a dryer (10) according to any of the claims 1 to 6 and interface means between the dryer (10) and the production device(s) (42) or storage means (44) for the prepared aggregate material (22).
9. An asphalt plant (40) according to claim 8 characterized in that the dryer (10) comprises
- a rotary drum dryer (170);
- a set of ring infeed (180);
- a first heating source (130) with the first zone heating direction (232) in the first direction (250);
- a second heating source (140) with the second zone heating direction (242) being counter-directional (270) to the first direction (250); and
- a first temperature (330) in the range between water's boiling point and a tem- perature at which bitumen starts to degrade so that development of blue smoke from the asphalt production is reduced.
10. A wood processing plant (40) comprising one or more production devices (42) or storage means (44) for prepared industrial use aggregate material (22), which plant (40) comprises a dryer (10) according lo any of the claims 1 to 6 and interface means between the dryer (10) and the production device(s) (42) or storage means (44) for the prepared aggregate material (22).
11. A method (400) for preparation of industrial use aggregate material (20) with a dryer (10) according to any of claim 1 to 6 comprising acts of:
- heating (410) said aggregate material (20) in the dryer (10) to a first temperature (330) in the first heating zone (230) using the first heat source (130) and;
- heating (410) said aggregate material (20) in the dryer (10) to a second temperature (340) in the second heating zone (240) using the second heat source (140), wherein the acts constitute a continuous process in a single chamber (ISO) and the first heating direction (232) and second heating direction (242) are substantially parallel to the flow direction (250).
12. Method (400) according to claim 11 comprising further acts of:
- regulating (420) the heat source output (360) of one or more heat sources (30) or material load (370) or a combination of heat source output (360) and material load (370);
- measuring (430) environmental conditions (350) inside the dryer (10); or - performing (440) a regulation of the heat source output (360) of one or more heat sources (30) or material load (370) or a combination of heat source output (360) and material load (370) based on input comprising measured (430) environmental conditions (350) inside the dryer.
13. Method (400) according to any of the claims 11 or 12 comprising a further act of feeding (450) aggregate material (20) into the chamber (150) through at least one addition infeed (160).
14. Method (400) of providing an industrial plant (40) with a dryer (10) according to any of the claims 1 to 6 for preparation of industrial use aggregate material (20) comprising acts of
- providing (460) an industrial plant (50); and
- retrofitting (470) the existing industrial plant (50) with the dryer (10).
15. Method (400) of providing an industrial plant (40) with a dryer (10) according to any of the claims 1 to 6 for preparation of industrial use aggregate material (20) comprising acts of
- providing (460) an industrial plant (50); and
- retrofitting (470) a single chamber (150) of an existing dryer (60) with a second heat source (140) and a second heating zone (240) where the first and second heat sources (130,140) are arranged with the first heating direction (232) and the second heating direction (242) being substantially parallel to the flow direction (250) and with the first heating direction (232) and the second heating direction (242) substantially facing each other.
16. Method (400) according to any of the claims 11 or 12 comprising the act of heating (410) and drying (480) the moist aggregate material (20) in the dryer (10) in the first heating zone (230) using the first heat source (130) by heating the aggregate material (20) to above the boiling point of the moisture contained in and to be removed from the aggregate material so that a phase transition of the moisture from liquid-phase to vapour-phase occurs.
PCT/DK2017/050010 2016-01-19 2017-01-19 Dryer for preparation of industrial use aggregate material WO2017125112A9 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DKPA201670026 2016-01-19
DKPA201670026 2016-01-19

Publications (2)

Publication Number Publication Date
WO2017125112A1 true true WO2017125112A1 (en) 2017-07-27
WO2017125112A9 true WO2017125112A9 (en) 2017-09-21

Family

ID=59361588

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DK2017/050010 WO2017125112A9 (en) 2016-01-19 2017-01-19 Dryer for preparation of industrial use aggregate material

Country Status (1)

Country Link
WO (1) WO2017125112A9 (en)

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1216667A (en) * 1914-12-07 1917-02-20 George F Downs Process of treating ores.
GB253049A (en) * 1926-03-03 1926-06-10 Ammann A G U Improvements in machines for drying road-making materials
US2264646A (en) * 1939-03-17 1941-12-02 Spears Joseph Mackay Rotary drier
US2290765A (en) * 1941-04-30 1942-07-21 Ivan J Overman Drier for aggregates and the like
US3729180A (en) * 1970-02-03 1973-04-24 Sud Ouest Ste Nationale Gaz Heated revolving drum
GB1416411A (en) * 1973-01-12 1975-12-03 Mcconnaughay K E Drier-mixing apparatus
US3989446A (en) * 1974-03-25 1976-11-02 Veitscher Magnesitwerke-Aktiengesellschaft Method and kiln for calcining finely divided material
US4856202A (en) * 1987-03-20 1989-08-15 Cyclean, Inc. Method and apparatus for treating asphaltic concrete paving materials
US4989986A (en) * 1989-05-15 1991-02-05 Cmi Corporation Double counter flow drum mixer
JPH03230085A (en) * 1990-09-19 1991-10-14 Niigata Eng Co Ltd Dryer of asphalt plant
US5083870A (en) * 1991-01-18 1992-01-28 Sindelar Robert A Asphalt plant with segmented drum and zonal heating
JP2001073312A (en) * 1999-09-06 2001-03-21 Tokyo Gas Co Ltd Site recycling system for paving scraps
US20060034738A1 (en) * 2001-04-25 2006-02-16 Albert Lebl Process and apparatus for the recovery of metal oxide particles

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1216667A (en) * 1914-12-07 1917-02-20 George F Downs Process of treating ores.
GB253049A (en) * 1926-03-03 1926-06-10 Ammann A G U Improvements in machines for drying road-making materials
US2264646A (en) * 1939-03-17 1941-12-02 Spears Joseph Mackay Rotary drier
US2290765A (en) * 1941-04-30 1942-07-21 Ivan J Overman Drier for aggregates and the like
US3729180A (en) * 1970-02-03 1973-04-24 Sud Ouest Ste Nationale Gaz Heated revolving drum
GB1416411A (en) * 1973-01-12 1975-12-03 Mcconnaughay K E Drier-mixing apparatus
US3989446A (en) * 1974-03-25 1976-11-02 Veitscher Magnesitwerke-Aktiengesellschaft Method and kiln for calcining finely divided material
US4856202A (en) * 1987-03-20 1989-08-15 Cyclean, Inc. Method and apparatus for treating asphaltic concrete paving materials
US4989986A (en) * 1989-05-15 1991-02-05 Cmi Corporation Double counter flow drum mixer
JPH03230085A (en) * 1990-09-19 1991-10-14 Niigata Eng Co Ltd Dryer of asphalt plant
US5083870A (en) * 1991-01-18 1992-01-28 Sindelar Robert A Asphalt plant with segmented drum and zonal heating
JP2001073312A (en) * 1999-09-06 2001-03-21 Tokyo Gas Co Ltd Site recycling system for paving scraps
US20060034738A1 (en) * 2001-04-25 2006-02-16 Albert Lebl Process and apparatus for the recovery of metal oxide particles

Also Published As

Publication number Publication date Type
WO2017125112A9 (en) 2017-09-21 application

Similar Documents

Publication Publication Date Title
US3401923A (en) Dryer
US5888256A (en) Managed composition of waste-derived fuel
US3074707A (en) Process for the manufacture of cement
US5557873A (en) Method of treating sludge containing fibrous material
US4332478A (en) Method and apparatus for reducing smoke emissions in an asphalt drum mixer
US4026717A (en) Economical, finely controlled cement production
US5279637A (en) Sludge treatment system
US5437850A (en) Method for calcining moist gypsum
US5291876A (en) Feed hopper for providing preheated aggregate material
US4600379A (en) Drum heating and mixing apparatus and method
US5201472A (en) Method for preparing and storing a recyclable shingle material
US3206526A (en) Utilization of cement kiln dust
US4387996A (en) Batch method of recycling asphaltic concrete
US5090813A (en) Dual drum recycle asphalt drying and mixing method and apparatus
US3971666A (en) Process for recycle of asphalt-aggregate compositions
US6164809A (en) Counter-flow asphalt plant with independently rotatable dryer and mixer
US2939693A (en) Rotary kiln
US4946283A (en) Apparatus for and methods of producing a hot asphaltic material
US6185842B1 (en) Apparatus and methods for controlling the temperature of exhaust gases in a drum mixer
US3832201A (en) Process for making asphalt paving compositions
US3578299A (en) Method and apparatus for cement kiln control
US20110129296A1 (en) Aggregate pre-heating systemsand method
CN101602518A (en) Production process for preparing calcium oxide and sulfur dioxide by decomposing ardealite
EP1547984A1 (en) Method and apparatus for stabilizing plaster
CN2627051Y (en) Asphalt concrete regeneration equipment

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17741129

Country of ref document: EP

Kind code of ref document: A1