JP2005283082A - Combustion gas drying system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drying system capable of differentiating a drying product and capable of modifying it into a high grade product. <P>SOLUTION: This combustion gas drying system is constituted of a combustion furnace having fire resistance, and using a destruction rubbish (mainly sawing lumber) as fuel, and a sealed drying place (treatment oven hereafter) having heat resistance or fire resistance connected by a wall having an opening for passing direct firing heat energy (combustion gas hereafter) such as the combustion gas, smoking heat and the like, and uses direct introduction of the combustion gas into a top part of a treated object or an upper part thereof in the treatment oven, as the first means for uniform drying. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a combustion gas drying process in various wood drying systems.

  Various methods for drying technology centered on wood have been developed and used from old rice. Typical drying methods are hot plate drying, vacuum drying, dehumidification drying, high frequency drying, etc., including a hot air drying method in which the temperature and humidity of the circulating air in the drying kiln are adjusted using electric heat or steam heat. Most of these drying methods are used for drying wood that has been cut into semi-finished products such as foundations, pillars, beams and plates. A method for directly drying pure log (log state) includes a combustion gas drying method in which the sawmill waste is directly fired as a heat source.

The combustion gas drying treatment method is sometimes referred to as a soot heat treatment method. The reason why the method was born is a drying method that was developed with the aim of improving the yield of lumber. The goal of the development method is to reduce the residual residual stress in the raw wood, to reduce the moisture content and to make the distribution uniform.
From an objective point of view, it has a self-propelled nature called log processing, discrimination as a soot processing material, and a large marketability. Furthermore, it is an excellent treatment method even from the viewpoint of social resources that use lumber waste as fuel.

  However, in today's dry wood products market, combustion gas dry lumber is given a much smaller position than other dry lumber. The largest cause of this result is none other than the low accuracy of the dried product and, among other things, its non-uniformity. This means that it cannot be achieved to the extent that a reduction in the target moisture content and a uniform distribution are expected. This is the result of entanglement of problems such as immaturity, inefficiency, and non-productivity of processing technology, and alienating the development of production processing technology. Surprisingly, when the background situation is analyzed, the main reason for the alienation is in the reason (target) itself of the present processing method, that is, the combustion gas drying method. Changing the consciousness in this direction and technically resolving to almost complete automation will all lead to the solution of the problem.

First of all, the main reason for the alienation is fuel in terms of technology, and consciously, the use of sawmill waste as fuel is directly linked to one of the improvements in sawmill yield. At the end of the day, the controversy between chickens and eggs will be controversial, but this is where the change in awareness leads to the significance of fuel technology reform. In addition, related problems and the great significance of problem solving are born.
That is, the reason and target of the combustion gas drying process

As described in, all of the solutions are to make a major shift to the sole propriety of the treated timber and the distinctive marketability of the treated product.

  Naturally ventilating is adopted as the combustion method of the combustion furnace that uses the sawn timber as fuel in the drying process. This is the most basic and natural combustion mode in which the soot that is the burning outlet of the combustion furnace is the lower part and the smoke outlet of the treatment kiln is the upper part. As a matter of course, the adjustment of the fuel, that is, the temperature adjustment of the processing kiln is artificially adjusted by the input amount of the sawdust. In some cases, a method of artificially adjusting the opening and closing degree of the opening that introduces the amount of combustion gas into the treatment kiln with a damper etc. is used together, but basically it is artificial fuel management, temperature management and day and night Regardless of whether or not the 24-hour artificial management. Although thermometers and temperature sensors may be equipped, both are facilities for visual recognition and are not linked to automatic management such as control processing or calculation processing. If you dare to write, there is no equipment to be linked or controlled.

  There are three main reasons for the generation of non-uniform processed products by the combustion gas drying method. One of them

The non-uniformity caused by the artificial fuel and temperature management mentioned in. The other is the method of introducing combustion gas in the drying furnace. In general, when drying wood with heat, a hot gas is introduced into the lower part of the processing kiln. This is the most primitive and natural method of moving the hot gas using the buoyancy of the introduced thermal energy. By the way, what happens if this natural advantage is applied in a container without pressure? The hot gas is only acted on by buoyancy and aims only upwards. This phenomenon has occurred in almost all combustion gas drying furnaces. The higher the gas temperature, the higher the combustion gas is aimed at the chimney at the top of the kiln. The log rises while acting only on the wood that touches the combustion gas on the way, and only the touched part. One of the inhomogeneities is thus born every day.

Another factor is the natural (horizontal) standing drying of the raw wood in the processing kiln. This is presumed to have been placed sideways simply due to the convenience of transporting and collecting raw wood. In addition, warehouses and factories where the structure of conventional drying furnaces can be used easily can be remodeled and used, and the ceiling height can be lowered when a new furnace is installed or when it is placed horizontally. It seems that the horizontal placement has become customary. However, the horizontal drying process of this raw wood is the biggest factor among the non-uniform factors.
Now, a hypothetical reasoning is made on one horizontally placed log in the drying kiln. Suppose that the combustion gas is heated uniformly from the front to the end. Moisture gas in the cell walls in the raw wood is condensed after thermal expansion to form water droplets. Moisture in the form of water droplets is gathered at the bottom of the raw wood that was placed horizontally by the action of gravity. When the raw wood has a bark, only 10 to 20% of the collected water evaporates even after continuous drying for about one week. Even without the bark of the raw wood, it is only about 50% water evaporation with the same drying process in the case of a complete log. Here, a large non-uniformity in temperature difference occurs inside and below the horizontally placed log. Further, the upper and lower temperature difference and the vertical stress cause a compressive stress in the upper part and a tensile stress in the lower part, resulting in non-uniformity due to the difference in stress inside the log.
These are the same as the events in steaming the charcoal or charcoal. When charcoal is burnt with the raw wood placed horizontally, the upper part of the horizontal wood is charred and charcoal, but the lower part is covered with firewood and burned. That is, it is burnt. This is one of the reasons why a pioneer who is a master of charcoal grills places logs vertically in a kiln.

Problems to be solved by the invention

  Conventional raw wood combustion gas drying process

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It is sure that the explanation contents overlap at the same time. However, solving the problem is nothing but solving the above three problems (factors) at the same time.

  Another helping solution is to establish the logic of the combustion gas drying process. Even now, the drying of wood is carried out with the fixed idea of drying with temperature. Drying is performed by the moisture absorption and dehumidification characteristic of wood, and the relative humidity must be adjusted to promote this humidity adjustment, and the temperature must be adjusted to adjust this relative humidity. It is not recognized too much. For this reason, no attention has been paid to the fact that a high temperature is adopted without any consideration and this high temperature creates further non-uniformity. The establishment of this logic is developed as a means for solving problems.

Means for solving the problem

  In the combustion gas drying method of the present invention, the combustion gas is introduced into the upper part of the treatment kiln. There is no chimney at the top of the introduced kiln. For this reason, the combustion gas shows a uniform spreading phenomenon in the upper part of the kiln. When this widened combustion gas becomes full at the same height as the opening of the combustion gas inlet, the specific volume of air in that portion increases, and the pressure corresponding to the change (rise) pressure of the water vapor partial pressure caused by this increases. Rises. As a result, when pressure energy that overcomes the buoyancy energy of the combustion gas is generated, the combustion gas descends to a place where the pressure is balanced aiming at a place where the pressure is low. Due to the pressure acting on the entire kiln, the state of the combustion gas descending is a uniform planar descending pressure. This planar uniform action is an absolute first condition that provides innocent uniformity for the raw wood drying process.

  In order for the combustion gas to continue to descend uniformly from the upper part to the lower part in the treatment kiln, it is necessary to always increase the pressure energy above a certain level to the combustion gas. The thermal energy of the combustion gas introduced into the upper part of the treatment kiln gives a part of heat to the moisture in the upper part of the log. About half of the heat-treated moisture is condensed to form water droplets and falls to the lower part, while the remaining water becomes latent heat of vaporization, that is, vapor gas, and is mixed with the combustion gas. For this reason, the combustion gas has a higher specific weight, overcomes the buoyancy, and descends downward. In this way, the combustion gas descends while slowly repeating the cycle of receiving gravitational energy corresponding to pressure energy instead of being deprived of thermal energy, and reaches the lower floor surface. This energy cycle is completely resistance loss in general wind calculation for combustion calculation, exhaust gas calculation with other temperatures, and the like, and corresponds to pressure loss therein. The logical use of the pressure loss is the establishment of the logic that guarantees complete uniformity, and is the greatest means of the present invention. Therefore, in the present invention, an outlet for smoke (combustion gas), that is, an inlet for a flue is provided on the floor surface or a lower wall surface that is almost as close to the floor surface.

In the present invention, as a means for completely eliminating the non-uniformity caused by the horizontal drying process of the raw wood, the raw wood is vertically dried.
At the top of the processing kiln

The pressure energy generated by the introduction of the combustion gas described in the section acts not only on the space above the processing furnace but also on the inner cell wall at the top, which is the end of the vertically placed raw wood. At this moment, at the top of the vertically placed raw wood, a humidity control action, that is, a moisture releasing action due to a difference in relative humidity inside and outside the raw wood begins. Moisture in the cell wall moves to the temporary canal by a dehumidifying action. Simultaneously with the movement of water, hot combustion gases flow into the cell walls. The flowing hot gas warms the cell walls, ie the heartwood of the raw wood. When the heartwood is warmed, the humidity control action is not completed, and a slight amount of water remaining on the cell wall is completely moved to the temporary canal.
The fiber direction of the vertical path of the log of the raw wood is the vertical direction that receives the gravitational action, and the water that has moved to the temporary path becomes a condensed water droplet that collects and drops due to gravity and acceleration of gravity. Then, the temporary path pipe is moved downward, and finally, it is discharged from the original mouth, which is the lower part of the raw wood, to the outside of the raw wood. This phenomenon is the same physical phenomenon as a phenomenon in which boiling water droplets flow out from the opposite side of the burning wood when a bonfire is made with a long wood.
A large moisture movement, that is, a reliable drying effect can be obtained with such energy that the log is placed vertically and the top of the log is uniformly stimulated with combustion gas. This is the biggest reason for the vertical placement of logs, a phenomenon that can never occur in the horizontal processing of logs. This phenomenon

The logic of the explanation is that the drying process is made to proceed perfectly with complete uniformity from the end of the raw wood to the bottom of the original wood. Furthermore, this uniform perfection is a major feature of the combustion gas drying process of the present invention that it can achieve tremendous reduction in processing time and great energy saving.

  The combustion method of the combustion furnace of the combustion gas drying method of the present invention is basically selected from the forced draft method. Depending on the location of the treatment facility, the climatic conditions, the height of the treatment kiln determined from the length of the treated raw wood, energy saving and other conditions, the natural ventilation type may be selected or used in combination with the forced ventilation type. When natural ventilation type is selected or when combined with indentation ventilation type and natural ventilation type operation is used in the processing process, the wind pressure and wind direction change due to weather conditions of the outside air, especially sudden changes in atmospheric pressure, and the balance of ventilation in the treatment furnace The flue collapses and the exhaust gas velocity in the chimney and chimney rapidly decreases, so that the flue and chimney may be rapidly cooled. In addition, it is cooled by a sudden drop in the outside air temperature, and the buoyancy of the exhaust combustion gas in the flue or chimney is reduced, resulting in a decrease in theoretical wind power. In order to prevent such unexpected accidents, it is possible to prevent cooling by passing a part of the flue and chimney through the combustion furnace, and to maintain the minimum stable theoretical wind power. Can do. This means has an effect of suppressing unnecessary safety factors even in the calculation process of intrusion wind power. In the combustion gas drying treatment method, the temperature in the treatment furnace and the specific gravity of the combustion gas vary greatly between the beginning of drying and the end of drying. For this reason, the dynamic pressure in the treatment kiln changes greatly. This change can be proportionally borne by the theoretical wind power of the flues and chimneys created in the combustion furnace. By executing this, there is no need to provide unnecessary power with the required ventilation power, and unnecessary exhaust of combustion gas can be prevented.

In the present invention, the automatic operation control system without taking in operation management in the processing facility without changing valuable lumber waste as fuel is incorporated as the following means.
Sawdust as fuel is thrown into the combustion furnace twice a day when the worker leaves the company and leaves the company. The temperature of the processing furnace is continuously adjusted by processing the amount of combustion air in the combustion furnace with the CPU using the temperature sensor signal of the processing furnace. The combustion air amount adjusting means is adjusted by opening and closing the electric damper when the combustion type operating means is a natural ventilation type, and by turning the supply air fan on and off when the driving type is a forced draft type. If the temperature adjustment is not required during operation of the processing apparatus, the air supply fan is stopped. However, even in this state, the smoke circulation fan between the treatment kiln and the combustion furnace is operated for the purpose of continuing the uniform soot treatment without the hot air in the treatment kiln remaining. The combustion method of the combustion furnace at this time is a natural ventilation type.

The invention's effect

Although the conventional combustion gas drying method seems to be an industrial method that is extremely widespread even when viewed objectively as direct drying of log logs and fuel for sawmill waste, it has hardly developed. One of the biggest factors is that the logic of the processing method has not been established.
Since the present invention presents a solution to the problem with specific and reliable means and logic first, we believe that it will be a stone for a great path not only in the wood processing industry but also in the dying domestic forest industry.

  The combustion gas drying method of the present invention achieves an absolute result by reliably and simultaneously practicing claims 1 to 6 with invariance. The results here are devoted to establishing trust and status in relevant social and industrial markets.

  Once the confidence and status of the combustion gas drying treatment system has been established, the next step is absolute product differentiation. One of the differentiators is to upgrade the processing accuracy of dry processed products that extrude smoke. In particular, when the strength and flavor comparable to historical old timber are produced, it will lead to the development of new demand. As a means for aiming at this distinctive upgrading, processing can be performed by increasing the number of humidity control operations in the drying process. In particular, the humidity control process for the soot treatment after the basic drying process has been completed exhibits a significant discriminating effect in a time of only 1 to 2 days.

  Based on claim 6 of the combustion gas drying processing system of the present invention, the degree of unmanned automatic control can be easily shifted from the unmanned for a long time to completely unmanned. This can be fully automated by using scrap wood as a chip material and using a mobile stalker and automatic charging machine often used in the coal era for the combustion furnace. This makes it possible to construct a large drying treatment facility at a huge accumulation base such as raw wood or a timber production base. We will revitalize the forest-related industries in the recession of domestically produced timber and contribute to the creation of large jobs.

Embodiments of the present invention will be described with reference to the drawings based on the embodiments.
FIG. 1 is a plan view of an integrated construction method of a combustion furnace and a processing kiln of a combustion gas drying processing method, and FIG. 2 shows a sectional view thereof. The structure of the furnace and kiln is made of reinforced concrete, but the construction method is selectively built according to the situation, such as on-site ramen structure, PC assembly method, PC box culvert method and others.

  The raw wood 11 is carried into the processing kiln 1 from the carry-in / out path 7 and accumulated in a vertically placed state. In the combustion furnace 2, a necessary amount of sawmill waste 12 as fuel (approximately equivalent to daily combustion consumption × ½) is charged and accumulated from the charging port 8.

  After confirming the state in which the fuel 12 of the combustion furnace is ignited and reliably continues combustion, the fuel input door 8 and the ash reservoir management door 9 which are the opening and closing ports of the combustion furnace 2 are securely closed. The operation switch of the automatic control panel 20 is turned ON to confirm the start of operation of the air supply fan 13 for taking in fresh air for combustion. After confirming the combustion gas (smoke) 15 from the loading / unloading path 7 of the processing furnace 1, the shutter 7 of the loading / unloading path is completely closed. After about 20 to 30 minutes thereafter, the temperature sensor 19 except for a part of fuel replenishment by checking steamy pale white gas (a dark white containing a large amount of steam during automatic operation) from the chimney 10c. And a fully automatic operation system that depends on the automatic control panel 20 is entered.

The route of the combustion gas 15 will be described with reference to the sectional view of FIG.
Fresh combustion air 17 is sent to the ash reservoir pit 6 at the lower part of the combustion furnace 2 by the air supply fan 13. Thereafter, it passes through the hearth 2b and enters the combustion furnace 2. The combustion gas 2 is burned in the combustion furnace 2 to generate high-temperature combustion gas 15. The combustion gas 15 is pushed up to the ceiling of the combustion furnace 2 by the dynamic pressure of the air supply fan 13 and the buoyancy created at a high temperature. Thereafter, the combustion gas 15 is sent out from the opening 4b of the partition wall 4a toward the processing kiln 1 according to the mixed pressure of dynamic pressure and buoyancy.

  In the treatment furnace 1, the combustion gas 15 introduced from the combustion furnace 2 fills up the treatment furnace upper space almost the same height as the opening 4b. After this, the combustion gas 15 is

As described above, the thermal energy is given to the log 11 and instead the gravitational energy corresponding to the pressure energy is received, and the entire kiln is slowly lowered to the treatment kiln floor 1a while being uniformly planarized. The combustion gas that has reached the kiln floor 1a is collected in a smoke collecting pit 10a that also serves as a drainage so as to crawl the floor surface.

  The combustion gas 15 collected in the smoke collection pit 10a is in a state where about 60% or more of the total energy is consumed in the drying process of the raw wood 11. About 70% or more of the energy remaining as the exhaust combustion gas 15 is the gravity energy of the water vapor gas that is not yet condensed and formed into water droplets. Continue on. When the flue 10b enters the combustion furnace 2, the exhaust combustion gas 15 is added to the buoyancy due to the heat of the combustion furnace and vigorously enters the chimney 10c and is then released to the outside air.

  It takes an average of four days for the drying process to be completed uniformly and completely after the combustion furnace 2 is ignited. In this average drying process time, the water content of the log 11 in the summer changes to a high rate of 1.5 times or more that of the log 11 in the winter, so that the process time extends from one day to two days in the summer.

  The first embodiment is an explanation of a basic drying processing method that focuses on completely uniform drying of the log 11. In the basic drying process so far, the large moisture conditioning action of the log 11 is only twice, including the moisture releasing action at the initial stage of drying and the moisture absorbing action at the end stage of drying.

As an initial means of differentiating the quality of dry-processed lumber products explained in, soot that does not involve high-temperature heat in accordance with the hygroscopic effect at the end of drying in only two humidity control operations of the basic drying process A large amount of gas 18 is generated in the combustion furnace 2 and this soot gas is sent to the processing furnace 1. The smoke gas 18 introduced into the treatment kiln 1 is sucked by the smoke circulation duct 22 connected to the smoke circulation fan 21 in the smoke collection pit 10a, and is again returned to the combustion furnace 2 via the ashes pit 6. The feed smoke gas 18 is circulated. As the generated fuel of the soot gas 18, sawdust or the like introduced into the combustion furnace 2 in advance and dried for convenience is used. In this case, the combustion method of the combustion furnace 2 is a natural ventilation type, the air supply electric damper 14 is opened, and the air supply fan 13 is stopped.

  The drying furnace system of the invention can be applied to uses such as fumigation treatment of wood, impregnation treatment with preservatives, impregnation treatment with flameproofing and fireproofing agents.

  It is a figure which shows the plane of the basic form of the combustion gas drying processing system concerning Example 1 and Example 2 of this invention.   It is a figure which shows the cross section of the basic form of the combustion gas drying processing system concerning Example 1 and Example 2 of this invention.

Explanation of symbols

1 Processing kiln (made of concrete)
1a Treatment kiln floor (concrete)
1b Floor grating 2 Combustion furnace (Finish with fire resistance)
2a Combustion hearth (fireproof finish)
2b hearth (casting grating)
3a outer wall (made of concrete)
3b Outer wall (internal fireproof finish)
4a Bulkhead (= inner wall, combustion furnace side fireproof finish)
4b Opening (combustion gas passage)
5a Roof (concrete)
5b Roof (internal fireproof finish)
6 Ash storage pit 7 Firewood entry / exit fire prevention shutter 8 Fuel (sawmill sawn) fire door 9 Ash storage pit management fire door 10a Smoke collection pit (also used as drainage pit)
10b Chimney 10c Chimney 10d Flue protection concrete 11 Log (vertical)
12 Fuel (sawmill waste)
DESCRIPTION OF SYMBOLS 13 Supply air fan 14 Supply electric damper 15 Combustion gas 16 Combustion exhaust gas 17 Fresh air 18 Circulating smoke gas 19 Temperature sensor 20 Automatic control panel 21 Smoke circulation fan 22 Smoke circulation duct

Claims (6)

  Combustion furnace that has fire resistance and uses waste materials (mainly sawmill waste) as fuel, and an opening (duct) for passing direct heat energy (hereinafter referred to as combustion gas) such as combustion gas and smoke heat Are connected to a wall (hereinafter referred to as a partition wall) having a heat-resistant or fire-resistant sealed drying processing place (hereinafter referred to as a processing kiln), and an object to be processed inside the processing kiln. Combustion gas drying characterized in that the first means of uniform drying is to directly introduce the combustion gas to the top of or the top of (a raw wood or a semi-timber lumber, etc., hereinafter referred to as a raw wood for convenience) Processing method   The combustion gas introduced into the upper part of the treatment kiln according to claim 1 is filled in the upper part of the kiln, so that the pressure of the kiln rises slightly. As a second means of making the combustion gas uniformly act on the raw wood, the exhaust gas from the processing kiln (evaporation of the raw wood-containing moisture accompanying the heat treatment mainly from the sawdust waste and the smoke heat treatment) Combustion gas drying process characterized by providing an outlet (a place corresponding to the entrance of a flue or chimney) for gas or the like on the floor surface near the floor or the bottom of the processing kiln. method   In the drying treatment of the treatment kilns according to claim 1 and claim 2, not only drastically shortening the drying treatment period, but also using raw wood as a means for drastically improving drying uniformity in principle. Combustion gas drying process characterized by vertical processing (hereinafter referred to as vertical installation)   When the combustion method of the combustion furnace of claim 1 is operated by natural ventilation, the theoretical wind power is reduced by cooling or the like in the flue or chimney means of claim 2 depending on the climatic conditions of the outside air. May invite. Combustion characterized by means and characteristics of exhausting the flue and chimney connected to the smoke outlet of the processing kiln through the combustion furnace to the outside air for the purpose of supplementing this theoretical decrease in wind power Gas drying treatment method   Even if the temperature adjustment is not required during the treatment operation of the combustion gas drying treatment method of the present invention constituted by claim 1 to claim 4, etc., the smoke gas without high temperature is stably treated. Combustion gas drying treatment system with the purpose of providing a smoke circulation duct and a smoke circulation fan between the treatment furnace and the combustion furnace for the purpose of sending to the kiln   A temperature sensor, a regulator (including a computer, hereinafter referred to as a CPU), etc. for the purpose of adjusting the internal temperature of the processing furnace of claim 1 to a set temperature or an appropriate temperature for an unmanned automatic operation over a long period of time. Combustion gas drying method using a damper to adjust the amount of combustion air in the combustion furnace

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