DK158404B - DRY DRUM SYSTEM FOR ORGANIC PRODUCTS - Google Patents

Description

in DK 158404 B

The invention relates to a drying drum plant for drying organic products, in particular agricultural products and of the kind specified in the preamble of claim 1.

It is well known to use dryer systems for drying 10 different agricultural products, e.g. cereals and vegetable crops. Such drying plants are very energy intensive, which of course applies especially to plants designed for drying vegetable crops with very high water content. The high energy prices therefore make it attractive to produce a dryer unit with less 15 energy consumption per unit. evaporated tons of water and at the same time removed some of the genes on the known drying systems. The genes are determined by the varying water content of the crops and the resulting varying yields. The variations in the yield volumes cause, at low yield rates, bonds of 20 dust particles in the exhaust system, which either results in reduced capacity in the plant or stops for cleaning of the exhaust system.

It is well known in the art to use a rotary drying drum, which is fed at one end with heated air and the goods to be dried, and in which there is a discharge chamber for material separation by means of a fan for conveying away drying air with particles. The particles are usually separated from the drying air in a cyclone.

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It is also known to control the air volume of the dryer with automatic or manual dampers. However, the disadvantages are a small regulatory area if condensation in the exhaust duct is to be avoided. There are quite narrow limits to how low the return-35 velocity can be so as not to get the build-up of coatings and clogging when the exhaust air is wet and dusty.

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Therefore, it is common practice to run at maximum air velocity and maximum temperature, regardless of the moisture content of the product to be dried, and whatever quantities are to be dried. This avoids frequent stops for cleaning of the return system, but gets a very poor energy economy.

German Patent Specification No. 2,650,919 discloses a drum dryer system for highly aqueous products where a portion of the dried product can be recycled to obtain a final product with 10 specific properties. The plant comprises one or more presses from which the press cakes are directed to a drum dryer, from which the exhaust air is conducted to a cyclone battery comprising a number of parallel coupled cyclones. This can undoubtedly achieve a desired end product with a certain grain size and moisture content, but this is done with a relatively large energy consumption, by recycling parts of the product to be able to control the drying process as desired.

The object of the invention is to provide a dryer drum system of the kind specified in the preamble of claim 1 which reduces both the energy consumption and the number of stops for cleaning of the return system, and where a plant is available which can be set for drying of very different crops. This is achieved by designing the system according to the invention as set forth in the characterizing part of claim 1.

By coupling the number of outlet lines with each dust extraction element corresponding to the amount of water to be dried, sufficient air velocity is always obtained, so that 30 condensation is completely avoided and the desired drying is achieved. The plant can be adjusted both for grain that is usually dehydrated 3-10% or for vegetable crops which need to be dried 70-90%. The plant never uses more energy than is just necessary to remove the amount of water in the drying material, so that a good energy economy is achieved, regardless of which product the plant processes, and it is not necessary to recycle parts of the drying material to control the drying process.

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Furthermore, the capacity of the plant becomes adjustable, which is a great practical advantage, although the greatest advantage is probably that the plant can be used for any finely divided organic product as desired desiccated.

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By designing the plant according to the invention as set forth in the characterizing part of claim 2, it is ensured that the exhaust air is still under full control, even after the dust or particle separation means. This is especially important when drying 10 crops with a very large dust content, where there will still be a smaller amount of dust, also in the exhaust air after the dust extraction means.

The exhaust air from the dust extraction means can be fed to each of its exhaust pipes, but preferably is fed to a common exhaust pipe as defined in the characterizing part of claim 3. This simplifies any final cleaning of the exhaust air, e.g. for particulate matter, with the use of a chimney filter or a dust burn.

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The system according to the invention may be designed as claimed in the characterizing part of claim 4. This provides a very efficient cleaning of the exhaust air. A cyclophane is a cyclone with its own fan and a particle mass dispenser.

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Finally, the system according to the invention can be designed as defined in the characterizing part of claim 5, thereby simply ensuring a constant flow rate in each discharge line from the drop chamber to the chimney. However, the individual discharge wires with dust extraction means need not have the same capacity or cross-sectional area to achieve the desired effect. One can, for example. well have a discharge line of 50m air / minute together with two discharge lines each of 3,300m air / minute and a discharge line of 200m air / minute, allowing 35 an appropriate number of combinations between 3 50m air / minute and 450m air /minute. Of course, you can also have a number of completely identical discharge lines, which simplifies

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the production of the plant and minimizes the number of spare parts.

The invention is then explained in more detail with reference to the drawing, which shows a functional diagram of a plant according to the invention with four discharge lines each with its own cyclophane.

In the drawing, 1 denotes a heater, for example an oil or gas burner, in connection with a fixed furnace 2 which supplies heated air to a drum dryer 3 with an inlet pipe 109 for the product to be dried. The product to be dried may be cereals, vegetable crops or any other crushed or finely divided product with a certain water content which is desirably dried, in whole or in part.

15 The outlet end of the dryer drum 3 enters an ejector housing 4 from whose bottom the dried goods are removed by means of a conveyor 5 and from which the top exhaust air is extracted.

In the drawing, it is schematically shown that from the top of the box 20 there are four discharge pipes 11 for each cyclophane 6 and each cyclophane has a discharge pipe 10 which is fed to a common chimney 7.

The upper left side of the drawing X is also schematically shown that it is also possible to pass the exhaust pipes 10 'from each cyclophane 6 to each of its chimney pipe 8.

Each discharge line comprising discharge pipe 11, cyclophane 6 and discharge pipe 10 or 10 'is arranged so as to maintain the velocity of the exhaust air and the separation of the particles, without the exhaust air condensing, thereby binding the particles to the conduit walls.

The number of cyclones in operation is adjusted according to production and the water content of the material to be dried out. The fan and the conveyor systems with dust or particle separators may be operated individually and individually regulated, e.g. by

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5 start-stop control, just as they can be cascaded.

This provides a plant which can be used for drying widely different crops with very different moisture content, and an energy saving, usually greater than 10%, will be achieved in relation to known plants.

Claims (5)

6 DK 158404 B Drying drum systems for drying organic products, especially agricultural products, comprising a rotatable dryer (3), an assembly (1,2) for producing heated drying air introduced at the entrance end of the drum, where there is also an entry tube (9) for the product to be dried and a chamber (4) at the outlet end of the drum for separating the dried product and the drying air, and the chamber (4) being provided with a plurality of outlet lines (11) comprising each of its particle separating means (6), characterized by: that the particle secreting means are arranged to be independently disconnected. Installation according to claim 1, characterized in that each particle separating means (6) each has its own discharge line (10, 10 '). Installation according to claim 2, characterized in that the 20 discharge lines (10) are fed to a common discharge pipe (7), e.g. a chimney. Plant according to claim 2, characterized in that the particle secreting means are cyclophanes (6) adapted to be cascaded. An installation according to claim 1 or 2, characterized in that both the discharge lines (11) from the chamber (4), which is preferably a drop chamber, and the discharge lines (10, 10 ') from the particle separating means (6) associated with each line, essentially the same cross-sectional area throughout the length of transport.