JPS60204644A - Product from catched dust at exhaust gas dust catcher in lime stone baking furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a product from dust contained in exhaust gas generated when limestone (calcium carbonate) is burned in a lime kiln to obtain quicklime (calcium oxide). be.

After the dust generated in conventional lime kilns is collected using various types of dust collectors, its components are a mixture of calcium carbonate, calcium hydroxide, unburned carbon, etc., so it appears gray and has a different color, so there is no effective way to use it. Instead, they are disposed of or supplied as raw materials for cement, etc.

Therefore, the reality is that we are forced to pay a considerable amount of processing and freight costs.

In view of the economic loss required for disposal of the dust collected by the exhaust gas dust collector and the fact that the main component of the dust collected by the exhaust gas dust collector is calcium carbonate, the inventors of the present invention have developed a new product of the dust collected by the exhaust gas dust collector. Rather than constructing a lime kiln for this purpose, we will process the dust collected by the exhaust gas dust collector most economically in the existing lime kiln, which is the source of the generation, and commercialize it as quicklime powder (calcium oxide powder). As a result of intensive research on the method, the dust collected by the exhaust gas dust collector is 900°.
It has been found that at temperatures above C, calcium carbonate and calcium hydroxide are converted to calcium oxide, unburned carbon is combusted, and unburned coal disappears.

The present invention was invented based on the above knowledge, and has the purpose of obtaining quicklime powder as a product from the dust contained in the exhaust gas collected by various exhaust gas dust collectors of lime kilns. The following longevity method is proposed.

That is, the dust contained in the exhaust gas collected by various exhaust gas dust collectors of the lime calcining furnace is fed again into the calcining zone of the lime calcining furnace, and the calcium carbonate and calcium hydroxide contained in the dust are oxidized. This refers to calcification and combustion of unburned fuel, which is then discharged as quicklime powder along with quicklime products to the product discharge from the lime kiln.

According to the method of the present invention, the collected dust that has passed through the part where the temperature of the lime kiln furnace, which is the source of the dust collected by the flue gas dust collector, is 900"C or more, is not recirculated to the flue gas dust collector. Unburned carbon is also removed by feeding the lime into the calcining zone using a pneumatic conveyor or the like, and lumps of quicklime (calcium oxide) are delivered to the product outlet of the lime kiln. ) This product can be extracted as quicklime powder (calcium oxide powder) along with the product, and the dust collected by exhaust gas dust collectors, which was conventionally discarded, can be commercialized, and it provides a manufacturing method that is economically and economically advantageous in terms of pollution prevention. Its industrial value is extremely large.

The effects of the present invention can be further emphasized as follows.

(1) The collected dust can be commercialized.

(2) Unburned carbon contained in dust etc. can be combusted.

(3) The above +1+ +21 leads to resource and energy conservation.

(4) The product yield rate improves due to the above (1).

(5) There is no cost involved in disposing of dust.

(6) Since the unburned carbon content in the dust can be reused without worrying, the excess air ratio can be reduced, resulting in energy savings and improved heat consumption per unit of product.

(7i) The present invention will be explained based on the embodiments shown in the drawings.

As shown in Figure Etj, in a vertical lime kiln consisting of two shafts, the lime kiln has a preheating zone (A) and a firing zone (B).
, a cooling zone (0), and a lance ()gunner) a.
[IL is installed in the preheating zone (A), and the product is discharged from the product discharge D (17).
The cyclone (1) is connected to the nog filter (2) through the pipe (2), and the bag filter (2) is connected to the chimney Q81 through the pipe (21).

According to method O of the present invention, the dust collected in the exhaust gas dust collection bags rd of the cyclone (1) and Nomag filter (2) is sent to the lime kiln in the following manner.

In other words, the cyclone-collected dust is double Dan, <-(3
+, through the screw conveyor (4) and rotary valve (5), and the bag filter collected dust through the screw conveyor (6), rotary valve (7), screw conveyor (8) and rotary valve (9) Once stored in the hotsuberan, the ejector is passed through the ball valve QB.
At step 02, the compressed air from the compressor (13) is used as a power source and is fed into the side channel section 04) at the lower part of the firing zone (B) of the vertical lime kiln through steel pipe piping.

The pressure of compressed air as above is 2Kp/c++! When the air consumption was 34 N/hour and the amount of dust collected by the ejector was 4.7 t/day, the operation was carried out at 8 production and 160 tons. The degree of dust, components and amount derived are as shown in Table 1.

Table 1 As shown in Table 1, the dust fed into the vertical lime kiln is not recirculated to the exhaust gas dust collector.

The particle size and composition of the quicklime (calcium oxide) product at the product outlet (17) are as shown in Table 2.

As shown in Table 2, the dust fed into the vertical lime kiln is taken out as quicklime powder (calcium oxide powder) from the outlet of the vertical lime kiln.

As shown in Table 2 above, the dust collected by the flue gas dust collector sent into the firing zone of the lime kiln passes through the lime kiln and is not circulated to the flue gas dust collector again to be collected. This is an extremely useful invention because it can be made into a product and taken out as quicklime powder from the product outlet without adversely affecting the lump quicklime (block calcium oxide) that is the product of the kiln.

[Brief explanation of the drawing]

The drawing shows an apparatus for carrying out the method of the invention. (1) Cyclone f2+ Bag filter 00) Hopper α2 Ejector αJ Compressor 04) ...Side channel input port (17)
...Product outlet patent applicant Yabashi Kogyo Co., Ltd.

Claims (1)

[Claims] The dust contained in the exhaust gas collected by various exhaust gas dust collectors of the lime kiln is sent again to the calcining zone of the lime kiln, and the calcium carbonate and calcium hydroxide contained in the dust are converted to calcium oxide. The collected dust of an exhaust gas dust collector in a lime kiln is characterized in that the unburned fuel is combusted, and the collected dust is discharged into the product outlet of the lime kiln as quicklime powder together with the quicklime product. How to commercialize it.