JPS60174419A - Method of processing waste liquid from calcining furnace - Google Patents

Abstract

PURPOSE:To perform a more economical combustion process with a small-sized device by a method wherein a heater is arranged at an outer wall surface of a fluidized bed part of a calcining furnace and a heat can be supplied within the furnace and also a thermal insulation material is attached in it. CONSTITUTION:A fluidized gas 8 heated by an external heater 7 is passed through an outer dissipating plate 5, thereafter a fluidized bed medium 9 in the fluidized bed is heated and agitated. When processed waste liquid 10 is sprayed into the fluidized bed to perform a combustion treatment, moisture content in the processed waste liquid is evaporated, so that a temperature of the flowing medium 9 is apt to decrease under a latent heat of the liquid. Due to this fact, a fluidized bed heater 6 is arranged, the temperature of the fluidized gas 8 is not decreased, but the processed waste liquid is burnt under a condition in which the gas is kept at a desired combustion processing temperature. With this arrangement, it is made possible to perform a more economical combustion process with a device with a size reduced to the minimum possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating waste liquid from a fluidized bed smoker.

Conventionally, fluidized bed smoking furnaces have relied on the heat retained in fluidizing gas as the heat source required for staged burning treatment of waste liquid and the like.

In other words, water was evaporated using only the enthalpy of the gas.

Figure 1 shows an outline of a conventional method for treating waste liquid from a rice baking furnace.

In the figure, the symbol is the smoking furnace, 2 is the wind box part, 3 is the fluidized bed part, 4 is the freeboard part, 5 is the distribution plate, 6 is the fluidized bed part heater, 7 is the external heater, and 8 is the fluidized bed part. 9 is a fluidizing medium, 1o is a treated waste liquid, and 11 is a gas outlet.

The treated waste liquid 10 supplied to the fluidized bed section 3 of the smoldering furnace 1 comes into contact with the fluidizing gas 8 heated by the external heater 7 and is smoldered. However, in general, when this fluidizing gas 8 is heated to a high temperature, depending on the properties of the treated waste liquid 1o, solutes in the waste liquid may melt and solidify, causing the fluidity limit to be exceeded. There was also the issue of heat resistance of the parts, and the gas temperature had to be kept below a certain level. For example, when a radioactive waste liquid containing boric acid is roasted, if the temperature of the fluidizing gas 8 is about 550'C or higher, borates and the like will melt and stick to the distribution plate 5 and the components in the furnace, forming flinkers. Dispersion plate 5
This increases the pressure loss and eventually causes problems such as impossibility of flow. Further, the need to keep the gas temperature below the above-mentioned constant value means that the enthalpy of the fluidizing gas 8 is limited, making it impossible to increase the power burning capacity of the waste liquid.

Therefore, when increasing the processing capacity of a smoldering furnace, the inner diameter of the furnace has been increased, but the amount of heat is However, this method increases the amount of exhaust gas, making the equipment larger and increasing costs.

The present invention has been made in view of the problems of the conventional examples, and it is an object of the present invention to provide equipment that is as small as possible and can perform smoking process economically.

In some fluidized bed type smoking furnaces, a heat insulating material (calcium silicate, etc.) of about 150 nnn is provided on the outer surface of the furnace wall, but the present invention provides a heater on the outer wall surface of the fluidized bed portion of the smoking furnace. The furnace is characterized in that it is equipped with a heater to supply heat to the inside of the furnace, and also includes several types of heat insulation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 2 shows a smoking furnace according to the present invention. In the figure, parts numbers 1 to 11 are the same as in FIG. 1 above.

11 The infertility furnace 1 is roughly divided into a wind box part 2, a fluidized bed part 3, a freeboard part 4, and a dispersion plate 5 located between the wind box part 2 and the fluidized bed part 30. Further, in the present invention, a fluidized bed section heater 6 is provided on the wall surface of this fluidized bed section 3.

The fluidizing gas 8 heated by the external heater 7 passes through the distribution plate 5
After passing through the fluidized bed, the fluidized medium 9 in the fluidized bed is heated and stirred. When 1° of treated waste liquid is sprayed into this fluidized bed to carry out the smoldering process, the water in the treated waste liquid evaporates, and the temperature of the fluidized medium 9 tends to drop due to its latent heat.

In order to compensate for this temperature drop in the fluidized medium 9 and compensate for the latent heat of vaporization, heat is supplied from the wall surface to perform a predetermined stage baking process.

By providing the fluidized bed section heater 6, this fluidized bed has the effect of being able to smoke the treated waste liquid while maintaining the temperature of the fluidizing gas 8 at a predetermined roasting temperature without lowering it. If the heater 6 is not provided, the enthalpy of the fluidizing gas 8 compensates for the latent heat of vaporization, which lowers the gas temperature and makes it difficult to maintain a predetermined processing temperature.

Furthermore, if the temperature of the fluidizing gas is increased in advance by the amount of the latent heat of vaporization in order to obtain a predetermined processing temperature, the temperature near the dispersion plate may become high, and the fluidizing medium 9 may melt and form solids. It may cause trouble.

As a specific example, the situation of the heater 6 is shown in Figure 3 (al.
, tb+, and an example of smoking radioactive liquid waste will be explained. temperature) is approximately 300
℃～350℃. When this one-stage burning process is carried out in a fluidized bed type smoking furnace with the same inner diameter, the following difference occurs depending on the presence or absence of the fluidized bed heater 6. Heat the chemical gaff 8 to the maximum temperature of approximately 500℃ and process it appropriately.
The difference between the instep temperature of about 300℃~350℃ (about 150~200℃)
°C) was used for water evaporation - the processing capacity of the concentrated waste liquid at this time was about 25 o1 (concentrated waste liquid) 7 m2 (cross-sectional area of the fluidized bed/H).

However, as a result of installing the fluidized bed section heater 6 and performing the same smoldering process, the fluidizing gas temperature was reduced to approximately 300 to 350°.
Even though it was CKed and smoked, the processing capacity was about 5.
We were able to improve this by more than 0%.

The reason why the appropriate treatment hot water temperature is 300 to 350°C will be explained. ' When waste liquid containing oxalic acid is smoked, caustic soda is generally added to the waste liquid, and Horax Na,2 B, which is a compound of boron and thorium, is produced as a smoldering product.
407·nH,,o) are mainly obtained. n at this time
The molecular crystallization water varies depending on the processing temperature, and varies from 10 molecules (at room temperature) to anhydrous (320° C.).

Here, we set the appropriate temperature to 300 to 300℃ to perform a thorough one-burning process and not to raise the temperature higher than necessary.
It is 50°C, so it is.

Next, an example of heater output will be described.

When the waste liquid is smoked at 110 fl/H, the inner diameter of the roasting furnace is approximately 750 mmφ, and the heater output is approximately 100 PW.

Of this 100 KW, 50 KW is constantly used as a base heater, and the remaining 50 KW is used to maintain the furnace temperature at a constant temperature (
For example, in order to adjust the temperature to 350° C., output control is performed in accordance with changes in the amount of roasting.

The fluidizing cuff is approximately 1050 ''/
H, supplied at 350°C, and the static bed height of the fluidized bed is approximately 600°C.
．． As a supplement to FIG. 3, which is H, the heater number situation is shown in FIG. 4+a+ and (b).

In the figure, numerals 3, 5, 6, 10 indicate the same parts as in the previous figure, and 12 is a nozzle stand, 13 is a heat insulating material, 14 is a body (shell), 15 is a heat insulating outer surface, 16 is a furnace inside, 17 indicates a terminal box.

The heater 6 is an electric heater in this example, and is mounted by vertically fixing the heater 6 to the fluidized bed section 3 with clamps. in this case,
As an example, the total number is divided by 100 to give an output of 100KW. The nozzles 12 are grouped in the same direction on the circumference, and the heater 6 is attached to the remaining portion.

The heater 6 is attached to the outer surface 15 of the furnace wall using a clamp, and no heat insulating material 13 is applied thereon. This heater 6 and heat insulating material 13
shall be removable.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a fluidized bed type kiln showing a conventional waste liquid treatment method, and Fig. 2 is a cross-sectional view of a kiln showing a treatment method of the present invention.
Figure 3 fal is a front view showing several examples of the fluidized bed section and the heater;
Figure 3 (bl is a cross-sectional view taken along the line A-A of Figure 3 (a), Figure 4 (al is a cross-sectional view showing the heater installation situation, Figure 4 fbl is a cross-sectional view taken along the line A-A of Figure 4 fal)・ 1. Burning furnace, 2. Wind box section, 3. Fluidized bed section, 4
...Freeboard section, 5.Dispersion plate, 6.Heater, 7
...external heater, 8.. fluidizing gas, 9.. fluidizing medium,
10... Processing waste liquid, 11... Gas outlet, 13... Heat insulation material. Figure 1 Figure 2 Figure 3 Figure 4 Continued from page 1 @ Inventor Naoyuki Uejima @ Inventor Hashimoto Yasue 2-1-1 Shinhama, Arai-cho, Takasago City Mitsubishi Heavy Industries, Ltd. Takako 5-chome, Komatsudori, Hyogo-ku, Kobe City No. 1-16 Inside Ryoju Environmental Distribution Engineering Co., Ltd.

Claims (1)

[Claims] The waste liquid is supplied to the fluidized bed part of the fluidized N smoking furnace and burnt out f! 4
'． In the method of
A method for treating waste liquid from a burning furnace, characterized by fluidized smoldering at ~350°C.