JPH11217576A - Co-fuel for cement calcination and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a co-fuel for cement calcination by effectively recycling water-containing organic sludge and to provide a method for simply and economically producing this fuel. SOLUTION: This co-fuel for cement calcination is in the form of granules having a water content of <=10 wt.% and a diameter of 0.1-10 mm, obtained by granulating and drying a water-containing organic sludge, such as sewage sludge, the residual sludge from food processing or sludge from paper manufacturing. The co-fuel is produced by dehydrating a water-containing organic sludge to yield an organic dehydrated cake, mixing and granulating the cake by use of a two-shaft mixer followed by drying in a hot-air parallel-stream rotary drying drum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary fuel obtained by effectively reusing a large amount of hydrous organic sludge generated from a sewage treatment plant, a food processing plant, a paper mill, and the like. The present invention relates to a method that can be used and a method for manufacturing the same.

[0002]

2. Description of the Related Art How to treat sludge whose amount is increasing year by year is a major problem. Conventionally, landfills have been directly disposed of, or sludge has been concentrated, dewatered, and incinerated for the purpose of detoxification, and the incineration generated has been dumped. However, although the dumping process is simple, it is not preferable because it may lead to environmental destruction of the dumping site, and the number of dumping sites is currently small. Therefore, it has been proposed to reuse sludge as fuel.

[0003] An object of the present invention is to provide an auxiliary fuel for cement calcination obtained by effectively reusing hydrous organic sludge, and a production method capable of obtaining the auxiliary fuel simply and inexpensively.

[0004]

In order to achieve the above-mentioned object, the invention according to claim 1 is a granulated product obtained by granulating and drying a hydrous organic sludge, and having a water content of 10% or less. An auxiliary fuel for sintering cement, having a particle size of 0.1 to 10 mm.

[0005] In the cement burning auxiliary fuel according to the first aspect, the organic component, ie, the combustible component of the hydrous organic sludge is effectively used as a part of the fuel and the inorganic component is also effectively used as a part of the cement raw material. Such an auxiliary fuel for calcining cement is used by being introduced into a raw material process, a calciner, or a kiln of a cement manufacturing plant.

According to a second aspect of the present invention, in the first aspect, the hydrated organic sludge is sewage sludge, night soil sludge,
It is at least one of livestock excrement sludge, residue sludge generated in food processing, residue sludge generated in fish processing, and residue sludge generated in paper and pulp processing. In addition, as foods for food processing, beer, shochu, coffee and the like can be mentioned.

According to a third aspect of the present invention, an aqueous dewatered organic sludge is dewatered to obtain an organic dewatered cake, which is mixed and granulated by a twin-screw mixer, and then dried by a hot-air co-current rotary drying drum. A method for producing an auxiliary fuel for cement firing, characterized in that:

According to a fourth aspect of the present invention, in the third aspect of the present invention, the organic dewatered cake is mixed with the organic sludge dried granules obtained by granulating and drying the organic dewatered cake in a twin-screw mixer. The solids are supplied at a solid content ratio of 1: 0.5 to 10 by weight.

FIG. 1 is a process chart of production and use of an auxiliary fuel for burning cement. Reference numeral 10 denotes a facility for manufacturing an auxiliary fuel for cement firing, and reference numeral 20 denotes a cement manufacturing factory. The production of auxiliary fuel for cement firing is performed as follows. That is, the water-containing organic sludge as a raw material is subjected to dehydration treatment to obtain an organic dewatered cake. The granulated material is obtained by the mixing and granulation treatment, and the granulated material is supplied to a hot-air co-current rotary drying drum and dried to obtain dried organic sludge granules (dry pellets). The dried organic sludge granules obtained by the drying process are put into a classifier and classified, and those having a particle size within a predetermined range are formed into dry pellets. Dry sludge. Then, the dried pellets are put into a raw material process, a calciner, or a kiln of the cement manufacturing plant 20 as an auxiliary fuel for cement firing, and are used as a part of the fuel.

It is preferable that the supply ratio of the organic dewatered cake to the recirculated dry sludge is 1: 0.5 to 10 in terms of solid content weight ratio. According to this, it is easy to set the particle size of the dried pellet. That is, when the ratio of the recirculated dry sludge to the organic dewatered cake is reduced, dried pellets having a large particle size are obtained, and when the ratio is increased, dried pellets having a small particle size are obtained. Therefore, it is easy to transport the dried pellets to a cement manufacturing plant, or to put them in a raw material process, a calciner, or a kiln, and to obtain dried pellets having excellent combustion efficiency.

As shown in FIG. 2, the twin-screw mixer has two parallel rotating shafts in which a large number of paddles 4 are arranged and fixed in an axial direction within a casing 3 comprising a trough 31 and a lid 32 for closing the trough. By rotating the shaft 5, mixed granulation is performed. A and B in the figure indicate the rotation direction. When the organic dewatered cake and the recirculated dry sludge are supplied to the twin-screw mixer, the two are mixed and kneaded by a rotating paddle, and the cross-linking force due to the viscosity of the organic dewatered cake and the movement of the adsorbed moisture to the recirculated dry sludge. Agglomeration, that is, both are mixed and granulated to obtain a granular material.

As shown in FIG. 3, the hot air co-current rotary drying drum rotates about a horizontal axis having a supply port 6 for the material to be dried on one end side and a discharge port 7 on the other end side. Drum 8
The drying target supplied to the inside of the drum 8 is transferred to the other end surface side while being dried by the hot air flowing in parallel and discharged from the discharge port. The inside of the drum 8 is partitioned in the transfer direction by a number of baffle rings 91, and a flow of hot air is generated as shown by an arrow in the figure.
The temperature of the hot air is 450 ° C. at the supply port 6 and 120 ° C. at the discharge port 7. When the granules obtained by the twin-screw mixer are supplied to the drying drum, the granules are dried by being brought into contact with the hot air flowing concurrently while being scooped up or dropped by the paddle 92 provided in the drum 8. Is done. Thereby, an organic sludge dry granular material is obtained.

According to a fifth aspect of the present invention, in the third aspect of the invention, the hydrated organic sludge is sewage sludge, night soil sludge,
It is at least one of livestock excrement sludge, residue sludge generated in food processing, residue sludge generated in fish processing, and residue sludge generated in paper and pulp processing. In addition, as foods for food processing, beer, shochu, coffee and the like can be mentioned.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) First, sewage sludge is dewatered to obtain a water content of 80%, an organic content of 17%, and an inorganic content of 3%.
% Organic dehydrated cake was obtained.

Next, the organic dewatered cake obtained above and the recirculated dry sludge obtained by granulating and drying the organic dewatered cake are mixed at a solids weight ratio of 1: 2 with a twin-screw mixer. And mixed and granulated. As a result, a granular material composed of a mixture of the two was obtained. Next, the granules obtained above were supplied to a hot air co-current rotary drying drum to be dried. The maximum drying temperature of the material to be dried was 100 ° C. And the obtained organic sludge dry granular material was classified.

As a result, dried pellets were obtained. This dried pellet has a particle size of 2 to 5 mm, a component having a moisture content of 8%,
The inorganic content was 14% and the organic content was 78%. The calorific value of the dried pellet was 3,900 kcal / kg, which was useful as an auxiliary fuel for cement firing. That is, by putting the dried pellets into a calciner of a cement manufacturing plant, the contained organic component is effectively used as a part of the fuel for preheating the cement raw material, and the contained inorganic component is used as a part of the cement raw material. It was used effectively.

(Embodiment 2) First, sludge of food processing residue is dehydrated to obtain a water content of 61%, an organic content of 23%, and an inorganic content of 1%.
A 6% organic dehydrated cake was obtained.

Next, the organic dewatered cake obtained above and the circulating return dried sludge obtained by granulating and drying the organic dewatered cake are mixed at a solid content ratio of 1: 0.5 by weight. The mixture was supplied to a shaft mixer and mixed and granulated. As a result, a granular material composed of a mixture of the two was obtained. Next, the granules obtained above were supplied to a hot air co-current rotary drying drum to be dried. The maximum drying temperature of the material to be dried was 100 ° C. And the obtained organic sludge dry granular material was classified.

Thus, dried pellets were obtained. The dried pellets have a particle size of 7 to 10 mm and a component having a water content of 5
%, Inorganic content 39%, and organic content 56%. And the calorific value of the dried pellets is 2000 kcal / kg,
It was useful as an auxiliary fuel for cement firing. In other words, by introducing the dried pellets into the raw material process of a cement manufacturing plant, the organic content is effectively used as a part of the fuel for preheating the cement raw material, and the inorganic content is effectively used as a part of the cement raw material. Used.

(Embodiment 3) First, papermaking sludge was dewatered to obtain an organic dewatered cake having a water content of 82%, an organic content of 16%, and an inorganic content of 2%.

Next, the organic dewatered cake obtained above and the recirculated dry sludge obtained by granulating and drying the organic dewatered cake are mixed in a twin-screw mixer at a solid content weight ratio of 1:20. And mixed and granulated. As a result, a granular material composed of a mixture of the two was obtained. Next, the granular material obtained above is
It was supplied to a hot air co-current rotary drying drum and dried. The maximum drying temperature of the material to be dried was 95 ° C. And the obtained organic sludge dry granular material was classified.

Thus, a dried pellet was obtained. The dried pellets have a particle size of 0.5 to 2 mm and a component having a water content of 8
%, Inorganic content 11%, and organic content 81%. And the calorific value of the dried pellets is 3200 kcal / kg,
It was useful as an auxiliary fuel for cement firing. That is, by putting the dried pellets in front of the kiln kiln of a cement manufacturing plant, the organic content is effectively used as a part of the fuel for residual heat of the cement raw material, and the inorganic content is used as a part of the cement raw material. It was used effectively.

[0023]

According to the auxiliary fuel for firing cement of the first aspect, the following effects can be obtained. Since the water content is low, hygiene is high, odor generation is weak, and long-term storage is possible. Since the water content is low, the cement production conditions are not adversely affected, so that the cement production can be stably performed. Since it is a granular material, no powder is generated, and therefore, handling is easy and handling is possible even in a closed circuit. Since the granulated product is granulated and dried without adding any components other than the water-containing organic sludge as the raw material, the weight is 1/5 to 1/3 of the organic dewatered cake. Therefore, costs such as transportation can be reduced. Fuel and raw materials at cement manufacturing plants can be saved, and overall energy consumption and carbon dioxide emissions can be reduced. Harmful components such as heavy metals in the hydrated organic sludge, which is the raw material, are sealed in the cement and do not elute, so that environmental degradation can be prevented.

According to the auxiliary fuel for calcining cement according to the second aspect, various combustion characteristics, that is, fuel characteristics can be provided.

According to the method for producing an auxiliary fuel for cement burning according to the third aspect, the auxiliary fuel is simply and inexpensively obtained because it is only supplied to the twin-screw mixer and the hot air co-current rotary drying drum for processing. be able to. Also, since the drying temperature is low, most of the organic components in the hydrous organic sludge can be left in the auxiliary fuel. Therefore, an auxiliary fuel with high fuel efficiency can be obtained.

According to the method for producing an auxiliary fuel for cement burning according to the fourth aspect, the particle size of the auxiliary fuel can be adjusted. Therefore, in the cement production process, it is possible to obtain an auxiliary fuel which can be easily applied to any of the input to the raw material process, the input to the calciner, the input to the kiln, etc. Wide auxiliary fuel can be obtained.

According to the method for producing an auxiliary fuel for cement burning according to the fifth aspect, an auxiliary fuel having various combustion characteristics, that is, fuel characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a process diagram of production and use of an auxiliary fuel for cement firing according to the present invention.

FIG. 2 is a sectional view of a twin-screw mixer.

FIG. 3 is a cross-sectional view of a hot air co-current rotary drying drum.

[Explanation of symbols]

 8 drums

Claims (5)

[Claims] Claims: 1. A granulated material obtained by granulating and drying hydrous organic sludge, wherein the water content is 10% or less and the particle size is 0.1 to 10 mm. Auxiliary fuel. 2. The aqueous organic sludge is at least one of sewage sludge, human waste sludge, livestock excrement sludge, residue sludge generated in food processing, residue sludge generated in fish processing, and residue sludge generated in paper and pulp processing. The auxiliary fuel for calcining cement according to claim 1, which is one kind. 3. A cement characterized in that a water-containing organic sludge is dewatered to obtain an organic dewatered cake, which is mixed and granulated by a twin-screw mixer and then dried by a hot-air co-current rotary drying drum. Manufacturing method of auxiliary fuel for firing. 4. An organic dewatered cake, together with an organic sludge dried granule obtained by granulating and drying the organic dewatered cake,
4. The method for producing an auxiliary fuel for cement burning according to claim 3, wherein the auxiliary fuel is supplied to a twin-screw mixer, and the ratio of the two is in the range of 1: 0.5 to 10 in terms of solid content weight ratio. 5. The water-containing organic sludge is at least one of sewage sludge, human waste sludge, livestock excrement sludge, residue sludge generated in food processing, residue sludge generated in fish processing, and residue sludge generated in paper and pulp processing. The method for producing an auxiliary fuel for cement burning according to claim 3, which is one kind.