JPS5854354B2 - Dryer - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heated continuous operation dryer.

The following are known as heating drying operations for cylindrical and thin dryers (hereinafter simply referred to as dryers) that incorporate stirring, transporting means (hereinafter simply referred to as rotors).

(1) Direct heating: Hot air is introduced into the machine, and the material to be dried (hereinafter simply referred to as material) is dried using the heat of the hot air.

(2) Indirect heating: The material is dried by receiving conductive heat from a heat transfer body (jacket, spool, rotor, etc.).

(3) Normal heating; combination of direct heating and indirect heating The present invention relates to indirect heating, and as mentioned above, in a dryer with a built-in rotor, the amount of heat necessary for drying is introduced into the conductor. The heating medium (such as steam or other heating medium) applies heat to the heat transfer material such as the jacket, oven, or rotor, or to the material at the same time as the jacket and rotor, and then passes through the drain, oven, or circulating fluid. Usually, they are collected as waste or released to the outside.

It is common sense to use the minimum amount of gas (air, N2, or solvent gas, etc.) introduced into the cabin to transport evaporated gas or to promote evaporation for the purpose of more economical operation. Therefore, the exhaust gas is often high temperature and high humidity.

Normally, if the exhaust from the dryer generates dust, the dust is separated and removed, and if it does not contain any dust, it is discharged to the outside in a small amount, or the moisture evaporated in the condenser is removed. It will be recovered and recycled as a low-humidity gas.

On the other hand, the material is agitated and transferred inside the machine, receives heat from the machine wall or rotor, and from each other, increases the temperature of the material, and evaporates moisture to become a dry product. It receives heat from the rotor, buttons, and materials and reaches a high temperature, absorbs evaporated moisture (water vapor, solvent, etc.), and is exhausted in a highly humid state that is almost saturated.

In the past, even if the flow of the introduced gas was countercurrent to the in-machine transfer of material, the exhaust gas temperature was much higher than the material temperature supplied into the machine.

The present invention focuses on this and relates to a dryer that reuses the latent heat and sensible heat of the exhaust gas in the drying process.

In other words, in a cylindrical or groove-type heated continuous operation dryer that is equipped with an internal agitation or transfer means, high-temperature, high-humidity exhaust gas discharged from inside the dryer is exposed to the dryer. Sensible heat of the exhaust gas is introduced into a second heating section provided on the outer wall of the rear fuselage near dry sunrise,
The dryer is characterized in that it uses latent heat to supplement the amount of heat at the initial stage of the drying process.More specifically, it has a material intake 3, a dried product outlet 4, an introduction gas intake lower, and an exhaust gas outlet 8. A jacket 2 having steam inlets 5', 5'' and drains 6', 6'' is provided on the outer wall of the rear body 1 of the dryer incorporating stirring means, and a jacket 2 having steam inlets 5', 5'' and drains 6', 6'' is provided in the vicinity of the material population 3 so as to be parallel to the jacket 2. An exhaust gas jacket 13 having an exhaust gas port 12 and an exhaust gas drain 14 is provided on the outer wall of the rear body 1 as a second heating section, and an exhaust gas outlet 8 provided in the rear body 1 and the exhaust gas jacket 13 are provided. By introducing the exhaust gas into the jacket part near the material supply of the dryer,
Since the exhaust gas is highly humid or almost saturated as mentioned above, it condenses rapidly in this jacket section, making it possible to supply a large amount of heat into the cabin through the rear wall.

Next, examples of the present invention will be described.

FIG. 1 shows a conventionally used countercurrent operation cylindrical stirring type dryer, in which the material supplied from the material port 3 provided at one end of the rear barrel 1 becomes a dried product and is converted into a dry product outlet 4. The steam of the heating medium enters from the steam inlets 5', 5" provided in the jacket 2 and is discharged from the drains 6', 6", and the introduced gas enters from the introduction gas lower part and exits from the exhaust gas outlet 8. Exhaust is released.

9 is a stirring blade or a transfer blade provided on the rotating shaft.

On the other hand, as shown in FIG. 2, the present invention has a dryer constructed of the same members as those shown in FIG. A jacket 13 for exhaust gas as a heating part and a hot gas population 12 attached to it
, an exhaust gas drain 14 was provided, the aforementioned exhaust gas outlet 8 and the hot gas population 12 were connected through a connecting pipe 11, and the exhaust gas exiting from the exhaust gas outlet 8 was introduced into the exhaust gas jacket 13 as a heat source for the second heating section. The exhaust gas drain 1 is used to heat the rear body of the wet material inlet section, where the target temperature is low, and reuses the sensible heat and latent heat of the exhaust gas, which was previously discarded.
4, and is sent to the condensing device as needed to be recycled and used again.

Figure 3 shows a conventionally used cylindrical stirring type dryer with co-current operation.Each member and its name is the same as in Figure 1, and the direction of the internal transfer of materials and the flow of introduced gas is as shown in Figure 1. It's the opposite of that.

On the other hand, the present invention is as shown in FIG. 4, and each member, its name, function, and operation are as described in FIG. 2 and its explanation.

Next, the results of an experiment when the present invention was implemented in a cylindrical stirring type dryer will be shown, and the effects thereof will be explained.

Based on conventional technology, material supply amount 240 kg/H Material temperature 7°C Dry product temperature 79°C Material moisture 13.8 W, B Dry product moisture 8.1 W, B Jacket temperature 133°C (Approx. 2kg/+ return grade 1)
Introduced air amount 24 Nm3/H (30.8 kg/
H) Introduced air temperature: 7°C Exhaust temperature: 85°C Jacket drain amount: 34 kg/H Evaporated water content: 15 kg/H Exhaust saturation temperature at this time: 79°C The amount of heat required for drying at this time, Qt, is the amount of evaporated water, Ql, and the temperature If the increase is Q2, then Q is (209) (0,16-0,09) (552) = 8
080 (kc11t/H) Q2=(209) (0,3) (79-7)+(31
) (79-7)6710(kcat/H 0°, Qt-Q1+Q2-14790(kcat/H)
The temperature of the exhaust gas is the saturation temperature of 75°C, which is 0.481 (kg/
kg... water vapor/dry air), so the exhaust enthalpy is: 185=0.24X85+(595+0.45X85)
) (0,481) 325 (kcal/ky) The amount of heat released from the exhaust gas at this time is 325 When the exhaust gas is supplied to the exhaust gas jacket 12 installed in the vicinity of the exhaust gas, the following occurs.

Exhaust gas jacket inlet temperature: 85°C (79°C saturated) Exhaust gas jacket outlet temperature: 77°C (758°C saturated) Material temperature rise due to exhaust gas jacket section: 25°C (material is 3
2°C) To explain the heat transfer in this section in detail, the amount of heat Q3 received by the material to be dried is: Q3 = (209) (0,3) (32-7) + (317
) = 2.343 (km/H) Average temperature difference at this time (△t )mba) (32 The reason for such a high overall heat transfer coefficient is (1) the inner surface of the drying machine wall, that is, the exhaust gas jacket of 130 machines. Since the inner surface of the wall near the wet material inlet is wetted with wet material, the heat transfer coefficient on this surface is high.

(2) External surface of the drying machine wall, i.e. exhaust gas jacket 13
Since the temperature of the material to be dried on the side of the rear wall facing the rear wall is much lower than the saturation temperature of the exhaust gas, the exhaust gas introduced there will condense on this side, and the exhaust gas jacket 13 will always be in a wet state. Heat transfer coefficient is high.

Because of these two reasons, the overall heat transfer coefficient becomes an extremely high value, so it is possible to greatly improve the heat transfer effect by simply extending the length of the rear body of the dryer according to the prior art.

In addition, by applying the present invention, the amount of heat required for drying is 1479
Of the 0 body d/H, 2343 km/H will be filled with exhaust gas, so about 16 parts of the heat required for drying will be saved.

In addition, the heat value of the exhaust gas that can be achieved using conventional technology is approximately 1
0010 km/H, by applying the present invention, 1
The required amount of heat is reduced to 10010-2343=7667k/H.

By slightly extending the length of the rear body of the above-mentioned Tobutton dryer and installing an exhaust gas jacket, the waste heat can be recovered and used to supplement the heat of the first stage of drying, thereby saving heat. When a condensing device is installed after the exhaust gas outlet 8 and recirculated, the condensing device is
The effects of the present invention are high, such as being able to form a 5"-shaped structure, and it is extremely useful industrially.

[Brief explanation of drawings]

FIGS. 1 and 3 are sectional views showing the main parts of the prior art, and FIGS. 2 and 4 are sectional views showing the main parts of the embodiments of the present invention that can be pressed in each form. It is. In the figure, 1 is a rear body, 2 is a jacket, 8 is an exhaust gas outlet, 11 is a connecting pipe, 12 is an exhaust gas jacket, and 13 is a heat source inlet.

Claims (1)

[Claims] 1 It penetrates both ends of the machine body 1 having a material population 3, a dry product outlet 4, an introduction glass lower and an exhaust gas outlet 8, and is intercepted so as to be able to exert a stirring action over the entire area inside the machine body 1. This dryer has a rotating shaft equipped with stirring blades 9, and is provided with a jacket 2 having steam inlets 5', 5" and drains 6', 6" on the outer wall of the machine body 1, which are connected in parallel to the jacket 2. In order to Exhaust gas jacket 13
A dryer characterized in that exhaust gas ports 12 provided in the dryer are connected through a connecting pipe 11.