JPH08301635A - Exhaust heat recovery equipment for granulated slag manufacturing equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Suppressing abrasion of the inside of the heat exchanger for recovering the heat retained by the polluted hot water discharged from the granulated slag manufacturing equipment by the granulated slag particles in the polluted hot water. Moreover, it is possible to prevent the flow of the polluted hot water in the heat exchanger from being obstructed by the accumulation of the granulated slag particles and the adhesion of the silica scale. [Composition] In an exhaust heat recovery device of a water granulation slag manufacturing facility, comprising a heat exchanger 7 for recovering heat retained by polluted hot water containing water granulated slag particles discharged from the water granulated slag manufacturing facility, On the supply side of the contaminated hot water in the heat exchanger 7,
A classifying unit 12 is provided for separating and removing granulated slag particles having a predetermined particle size from the contaminated warm water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat recovery apparatus for a granulated slag manufacturing facility, and more particularly to an internal heat exchanger for recovering the heat of polluted hot water discharged from the granulated slag manufacturing facility. It is possible to suppress abrasion by the water granulated slag particles in the contaminated warm water, and further, it is possible to prevent the flow of the contaminated hot water in the heat exchanger due to the accumulation of the water granulated slag particles and the adhesion of silica scale, The present invention relates to an exhaust heat recovery device for a granulated slag manufacturing facility.

[0002]

2. Description of the Related Art For example, it is conceivable that the heat stored in molten slag discharged from a blast furnace is effectively used in accordance with the steps shown in FIG. That is, the molten slag discharged from the blast furnace (not shown) is fed into the blowing box 1. The molten slag sent into the blow-molded box 1 is crushed by being rapidly cooled by cooling water to be granulated slag. At this time, the thermal energy held by the molten slag is given to the cooling water to generate steam and hot water.

A kind of slurry-like mixture, which is generated in the blow box 1 and is composed of water granulated slag, steam and hot water and has a temperature of 100 ° C. or lower, enters the water granulated slag tank 2. The steam separated in the water granulation slag tank 2 is discharged as exhaust steam through the duct 3 to the outside of the system.

On the other hand, the slurry-like mixture of granulated slag and warm water in the granulated slag tank 2 is filtered by the filter 4
(Invar filter) separates water granulation slag and polluted warm water containing water granulation slag. The granulated slag separated by the filter 4 is sent to the product tank 5. on the other hand,
The contaminated hot water that has passed through the filter 4 is sent to the heat exchanger 7 by the hot water pump 6 and exchanges heat with the heated water. The polluted warm water that has exited the heat exchanger 7 and whose temperature has dropped is passed through the cooling tower 8, the water supply tank 9, and the water supply pump 10 to become cooling water of about 60 ° C., and is returned to the blow box 1 again. The clean hot water heated by the heat exchanger 7 is used as the hot water utilization facility 11
Sent to

In Japanese Unexamined Patent Publication No. 57-55391, in the above-described exhaust heat recovery method for granulated slag manufacturing equipment, instead of heating clean water in the heat exchanger 7, heat is recovered by using Freon. A method is disclosed.

[0006]

However, the above-mentioned conventional exhaust heat recovery method for water granulated slag manufacturing equipment has the following problems and is difficult to realize. The contaminated warm water that has passed through the filter 4 contains a large amount of granulated slag particles. Since the hardness of the granulated slag particles is extremely high, when the granulated slag particles pass through the heat exchanger 7, the inside of the heat exchanger 7 is worn. Granulated slag particles in the polluted warm water separated by the filter 4 are accumulated inside the heat exchanger 7,
The flow of polluted warm water inside is obstructed. A large amount of Si ions contained in the contaminated warm water that has passed through the filter 4 causes silica scale to adhere to the inside of the heat exchanger 7 and hinder the flow of the contaminated warm water in the heat exchanger 7.

Therefore, an object of the present invention is that the inside of a heat exchanger for recovering the heat retained by the polluted hot water discharged from the granulated slag manufacturing equipment is worn by the granulated slag particles in the polluted hot water. (EN) An exhaust heat recovery device for a granulated slag manufacturing facility, which can suppress the flow of polluted hot water in a heat exchanger due to the accumulation of granulated slag particles and the adhesion of silica scale. Especially.

[0008]

The present invention provides a granulated slag provided with a heat exchanger for recovering the heat retained in polluted hot water containing granulated slag particles discharged from a granulated slag manufacturing facility. In the exhaust heat recovery apparatus of a manufacturing facility, the supply side of the contaminated warm water in the heat exchanger is provided with a classification means for separating and removing the granulated slag particles exceeding a predetermined particle size from the contaminated warm water. Is to have.

Another feature of the present invention is that the classification means comprises:
It is a settling classifier.

Yet another feature of the present invention is that the classifying means is a cyclone type centrifugal classifier.

Still another feature of the present invention is that the classification means has a function of separating and removing the granulated slag particles having a particle size of more than 0.4 mm.

[0012]

[Function] In the vicinity of the heat transfer surface in the heat exchanger, there is a very thin laminar flow layer called a laminar flow bottom layer, which has the same diameter as the thickness of the laminar flow bottom layer, or If particles with a smaller particle size are mixed in the fluid flowing in the heat exchanger, the scale attached to the heat transfer surface can be removed. Seikei University Engineering Report No. 49 (1990).

Generally in terms of wear and deposition, particles of relatively small size contribute less to wear and
Difficult to accumulate in the heat exchanger. On the other hand, particles having a relatively large particle size make a large contribution to wear, and
Accumulates easily in the heat exchanger.

Therefore, if the granulated slag particles having the same diameter as the thickness dimension of the laminar flow bottom layer and exceeding the predetermined particle size are removed from the contaminated warm water supplied to the heat exchanger, the thickness dimension of the laminar flow bottom layer or less is obtained. Along with the effect of scale removal by the particle size,
It is possible to suppress wear inside the heat exchanger due to the water granulated slag particles and accumulation of the water granulated slag particles.

Since the thickness of the laminar bottom layer depends on the flow condition of the polluted hot water in the heat exchanger, the above-mentioned predetermined particle size of the granulated slag particles needs to be set according to the flow condition of the polluted hot water. There is. Under standard operating conditions of the heat exchanger, the flow condition of polluted hot water is 4 × 14 ^{4 in} terms of Reynolds number.
It is the above turbulent region.

Further, the mixing ratio of the water granulated slag particles in the polluted warm water discharged from the water granulated slag manufacturing facility is as small as about 0.1 to 1.0%. On the other hand, in the above-mentioned engineering report of Seikei University, an experiment of particle mixing is carried out at a mixing rate of about 0.3%, and the effect is mentioned. Therefore, when the flow condition of the polluted warm water is in the turbulent region and the mixing ratio of the granulated slag particles is 0.1 to 1.0%, the predetermined particle size is 0.4 m.
m is suitable.

As a classifying means for separating and removing granulated slag particles having a predetermined particle size or more from the sludge warm water, it has excellent classification accuracy, and the contaminated warm water contains a large amount of granulated slag particles. Therefore, it is preferable to have a function capable of continuously discharging the granulated slag particles separated and removed. A sedimentation classifier or a cyclone type centrifugal classifier is optimal as a classifying means satisfying such conditions.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the exhaust heat recovery system of the granulated slag manufacturing equipment of the present invention will be described with reference to the drawings.

FIG. 1 is a process diagram showing an exhaust heat recovery method by an exhaust heat recovery device of a granulated slag manufacturing facility according to the present invention.

In FIG. 1, 1 to 11 are the same as those in FIG. 3 showing the above-mentioned prior art, 1 is a blow box, 2 is a granulated slag tank, 3 is a duct, 4 is a filter. 5 is a product tank, 6 is a hot water pump, 7 is a heat exchanger, 8 is a cooling tower, 9 is a water supply tank, 10 is a water supply tank, and 11 is a hot water utilization facility.

The feature of the present invention resides in that the classification means 12 is provided on the supply side of the contaminated hot water in the heat exchanger 7, that is, in the middle of the pipe connecting the hot water pump 6 and the heat exchanger 7. As the classifying means 12, a sedimentation classifier or a cyclone type centrifugal classifier is used.

The classifying means 12 has a function of separating and removing granulated slag particles having a predetermined particle size from polluted warm water. That is, the contaminated hot water that has passed through the filter 4 is sent to the classifying means 12 by the hot water pump 6, where 0.4
The water granulated slag particles having a particle diameter of not more than mm and the water granulated slag particles having a particle diameter of more than 0.4 mm are classified. And 0.4
The polluted hot water containing the granulated slag particles having a particle size of mm or less is sent to the heat exchanger 7, and the granulated slag composed of the granulated slag particles having a particle size of more than 0.4 mm is sent to the product tank 5.

When separating the granulated slag particles exceeding 0.4 mm from the contaminated hot water by the settling classifier, the width of the settling tank is determined based on the flow rate of the contaminated warm water according to the existing formula derived from Stokes' equation. The length can be determined.

In this way, the classification means 12 is provided on the supply side of the contaminated warm water in the heat exchanger 7, and only the contaminated warm water containing the granulated slag particles having a particle size of 0.4 mm or less is supplied to the heat exchanger 7. As a result, it is possible to prevent the inside of the heat exchanger 7 from being worn by the granulated slag particles exceeding 0.4 mm in the contaminated warm water. Moreover, since the granulated slag particles having a particle size of 0.4 mm or less are less likely to be deposited due to the small particle size, and have a scale removing action, due to the deposition of the granulated slag particles and the adhesion of the silica scale,
It is possible to prevent the passage of dirty hot water in the heat exchanger from being hindered.

FIG. 2 shows a graph of the particle size distribution of the granulated slag particles contained in the polluted warm water discharged from the granulated blast furnace slag manufacturing facility. As shown in FIG. 2, the ratio of particles having a particle size of more than 0.4 mm is about 20% at most, so that the classifying unit 12 may be small in size as compared with the entire system including the heat exchanger.

[0026]

As described above, according to the present invention, a classifying means is provided on the supply side of the polluted warm water in the heat exchanger so that only the polluted warm water containing the granulated slag particles having a particle size of a predetermined particle size or less is provided. Supplying to the heat exchanger brings about the following industrially useful effects.

Since the polluted warm water contains only the granulated slag particles having a particle size not larger than the predetermined particle size, the inside of the heat exchanger can be suppressed from being worn by the granulated slag particles having a particle size larger than the predetermined particle size in the polluted warm water. Granulated slag particles having a particle size of a predetermined particle size or less are less likely to be deposited because they have a small particle size, and have a scale removing action. Therefore, due to the deposition of granulated slag particles and the adhesion of silica scale, the heat exchanger It is possible to prevent obstruction of the passage of polluted hot water. Since the silica scale is less likely to adhere to the inside of the heat exchanger, it is possible to reduce the pollution factor, thereby making the device compact, reducing the cost, and reducing the power consumption to save energy. Therefore, it becomes possible to recover the thermal energy held by the polluted hot water discharged from the granulated blast furnace slag manufacturing equipment, which has been difficult to implement in the past.

[Brief description of drawings]

FIG. 1 is a process diagram showing an exhaust heat recovery method by an exhaust heat recovery device of a granulated slag manufacturing facility of the present invention.

FIG. 2 is a graph showing a particle size distribution of granulated slag particles contained in polluted warm water discharged from a granulated blast furnace slag manufacturing facility.

FIG. 3 is a process diagram showing a conventional exhaust heat recovery method using an exhaust heat recovery device of a water granulated slag manufacturing facility.

[Explanation of symbols]

 1 Blowing Box 2 Granulated Slag Tank 3 Duct 4 Filter 5 Product Tank 6 Hot Water Pump 7 Heat Exchanger 8 Cooling Tower 9 Water Tank 10 Water Pump 11 Hot Water Utilization Facility 12 Classification Means

Claims (4)

[Claims] 1. An exhaust heat recovery apparatus for a water granulation slag manufacturing facility, comprising a heat exchanger for recovering the heat of the contaminated hot water containing the water granulated slag particles discharged from the water granulated slag manufacturing facility. In the heat exchanger, on the supply side of the contaminated hot water, a classification means for separating and removing the granulated slag particles exceeding a predetermined particle size from the contaminated warm water is provided,
Exhaust heat recovery equipment for granulated slag manufacturing equipment. 2. The exhaust heat recovery apparatus for granulated slag manufacturing equipment according to claim 1, wherein the classifying means is a settling classifier. 3. The exhaust heat recovery device of the granulated slag manufacturing equipment according to claim 1, wherein the classification means is a cyclone type centrifugal classifier. 4. The classifying means has a function of separating and removing the granulated slag particles having a particle size of more than 0.4 mm. Exhaust heat recovery device of granulated slag manufacturing facility described in one.