JPS638366B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a method for regenerating fluidized media to which sticky substances have adhered, and in particular to fluidized media used in fluidized bed incinerators that incinerate ash collected from the exhaust gas of power plant boilers (hereinafter referred to as EP ash). The present invention relates to a method for regenerating a fluidized bed in which sticky substances adhering to sand or the like used as a medium are removed, regenerated, and re-supplied to a fluidized bed incinerator for operation. Boilers that burn large amounts of heavy oil and crude oil, such as large thermal power plants, emit heavy oil ash (EP ash) that contains unburned carbon. When this heavy oil ash is treated as waste, it is not suitable for general landfilling due to its unique properties. Therefore, it is often processed by a specific company. Therefore, there are various problems such as increased transportation costs and handling problems due to the powder. For this reason, equipment has been developed as ancillary equipment to the large boiler that is the source of the ash, in order to solve or alleviate the above-mentioned problems by incinerating the heavy oil ash and measuring the volume and weight loss. In addition, the advantage of this device is that since the vanadium compounds contained in EP ash are concentrated, it can be evaluated on the same level as vanadium ore, and it has the added value of being advantageous in its handling. . There are various types of incinerators, but they have advantages and disadvantages, and it is well known that incineration of EP ash is not easy. Among these, equipment that processes EP ash using a fluidized bed furnace is considered important because it is relatively adaptable to load fluctuations and changes in ash composition. However, this fluidized bed incinerator also has the following drawbacks. In other words, the fluidizing medium (mainly sand is used) becomes economically swollen with deposits, causing poor flow and making long-term continuous operation difficult, so it is necessary to shut down the furnace and replace the medium. It is something that happens. This results in disadvantages in terms of workability, operating costs, media costs, etc., and improvements in these areas are desired. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for regenerating a fluidized medium, which eliminates the drawbacks of the prior art described above and allows continuous operation by regenerating and supplying the medium without stopping the furnace. In short, in the present invention, a medium is taken out continuously or discontinuously from an operating fluidized bed furnace for incinerating EP ash, water is added to the medium, and water is attached to the surface of the medium. Extract the water-soluble components in the ash of heavy oil ash,
Mechanically removes insoluble components whose adhesion has weakened,
This method is characterized by returning the recycled media sand to the fluidized bed and continuing the operation. Table 1 shows an example of the analytical values of what adhered to the fluidized medium when EP ash was incinerated in a fluidized bed incinerator.

[Table] As shown in this table, the main components are Na ₂ O, SO ₃
Therefore, these are thought to exist in the form of Na ₂ SO ₄ . Others are made of compounds such as V, Fe, and Ni. An easy way to separate deposits of this composition from the medium (mainly natural sand) is to crush them mechanically.
Although it is conceivable to separate the two, this method does not actually separate them for the following reason. This is because it is difficult to remove the deposits on the surface with the minimum force required to crush the sand in the medium, and if a force that crushes the deposits is applied, the medium itself will also be pulverized, defeating the original purpose of recycling. It has become clear that this will not be achieved. This is thought to be because the deposits have higher elasticity and are stronger against impact force than the medium.
Based on these facts, we focused on the composition of the deposits as a peeling method, and Na ₂ SO ₄ , which accounts for about 50%,
Since it is soluble in water, it was expected that the deposits would be easily peeled off when extracted with water, so we tried the following. As an example, first, sand extracted from a fluidized bed furnace containing 24.5% of deposits was mixed with water at a weight ratio of 1:1, placed in a ball mill, and subjected to wet crushing for 10 minutes. As a result, the removal rate of deposits is approximately 90%.
This value was higher than that of the dry crushing method described above, and it was confirmed from the analysis results of the exfoliated materials that there was almost no pulverization of the sand itself in the presence of water. When water-soluble substances are dissolved and removed, sand particles and other insoluble substances lose their adhesive connections to water and become fragmented, and even if these particles are connected, they become hard, spongy, hollow mesh-like particles that easily become particles when struck. This is the result. In addition, in order to increase the peeling rate, if the sand surface after wet crushing is washed with fresh water or with overwater of the treated water that has not reached saturation, the peeling rate will be higher. You can expect it. Furthermore, when the solubility of Glauber's salt (Na ₂ SO ₄ , IOH ₂ O) in water, that is, the amount dissolved in 1000 grams of water, is expressed in grams, the curve shown in Figure 1 is shown. The horizontal axis is the liquid temperature and the vertical axis is the amount of dissolved Glauber's salt. As can be seen from the drawing, there is a peak at approximately 33°C. On the other hand, as shown in Table 1, about 50% of the deposits on the fluid medium are Na ₂ SO ₄ , so the treated water is kept at 30°C.
It can be seen that the use of the above substances is effective in dissolving and removing them. The fluid medium is polyhedral and has concavities, but the deposits are V ₂ O ₅ , Al ₂ O ₃ ,
It is estimated that it forms a hard spongy body whose main components are Fe ₂ O ₃ and NiO, and this combination, with the skeleton filled with Glauber's salt, is the reason for the formation of a strongly elastic deposit. being thought about. Therefore, when dissolving in water to remove Glauber's salt, the hard spongy bodies are easily crushed and the fluidized medium can be returned to a state free of deposits. FIG. 2 is a drawing showing the arrangement flow of the apparatus according to the present invention. A fluidized medium that overflows or is extracted from a fluidized bed incinerator 1 that incinerates EP ash and that requires regeneration and has sticky substances attached thereto is sent to a crusher 2 through a pipe 11. Conduit 2
From No. 1, the unsaturated liquid of the sticky material is sent with water or the water used in the recycling treatment, and a mechanical force is applied as a crushing blow to peel off the sticky material, and stirring is performed. The medium that has remained in the crusher 2 for a certain period of time is sent to the separator 3 through a pipe 22.
Sent by. In the separator 3, a fluid medium such as sand and a slurry, which is a mixture of a solution of a water-soluble substance and a particulate insoluble substance, are separated. The treated fluidized medium is sent to the fluidized bed incinerator 1 through a pipe 31 and reused. The slurry is discharged from the pipe 32, concentrated or dried by the exhaust gas from the fluidized bed incinerator 1, and V ₂ O ₅ and the like are effectively utilized. By carrying out the present invention, it is possible to circulate and supply a fluidized medium in which sticky substances that hinder the formation of a fluidized bed in a fluidized bed incinerator are efficiently removed, thereby achieving stable incineration processing. This has various effects such as reducing the amount of media consumed, recovering V ₂ O ₅ , preventing a decrease in equipment efficiency due to shutdown, and eliminating the need for workers.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the solubility of Glauber's salt in water and the liquid temperature, and FIG. 2 is a diagram showing the arrangement of an apparatus and pipe lines according to the present invention. 1... Fluidized bed incinerator, 2... Crusher, 3... Separator, 11, 21, 22, 31, 32... Pipe line.

Claims (1)

[Claims] 1. The fluidized medium used in the operating fluidized bed reactor and which has deposits containing water-soluble and water-insoluble substances is continuously or discontinuously extracted, the medium is washed with water, and further subjected to mechanical action. A method for regenerating a fluid medium, characterized in that the adhering matter is peeled off and removed by applying the following.