KR100259318B1 - Structure of gasified and melting furnace - Google Patents

Abstract

PURPOSE: A furnace body structure for gasifying melting furnace is provided in which loading of waste and additives and measurement of a height of the waste deposition layer formed in a lower furnace portion can be performed without passing though the freeboard portion. CONSTITUTION: The furnace body structure for gasifying melting furnace comprises a freeboard portion whose center axis is shifted from a center axis of a lower furnace portion by 50% or more of an inner furnace diameter, to load waste and additives and to measure a height of a deposition layer formed in the lower furnace portion, without passing through the freeboard.

Description

Furnace structure of gasification furnace {STRUCTURE OF GASIFIED AND MELTING FURNACE}

The present invention relates to a structure and a work method of a gasification furnace.

First, the furnace structure will be described.

Conventionally, in the furnace structure of the gasification furnace and the ash melting furnace, a free board installed to suppress the generation of tar or dioxin in the exhaust gas or to prevent dust from scattering has been prepared so far as shown in FIG. 3. It has been installed above.

However, free boards have caused some problems because they occupy a large space just above the brazier.

The charge was supplied only from the oblique top side to the furnace body or from a supply port installed on the free board part. As a result, when injected from an oblique direction, the component adjusting material and the ash or waste added to the melt differ in their trajectory into the furnace due to the difference in specific gravity, resulting in uneven distribution of these. As a result, these mixtures became insufficient and the component adjustment was not good, so that the viscosity of the melt increased and the melt could not be discharged stably.

In addition, in the method disclosed in, for example, Japanese Patent Laid-Open Publication No. 89-184314, which is introduced from the free board portion, the amount of fly ash to be landfilled is increased because fines in the input waste become dust and are easily scattered. The disposal cost of waste increases significantly.

In addition, as described in Japanese Patent Laid-Open Publication No. 92-122486, even when charging auxiliary fuel such as coke, it is introduced at a quite high place, so the rate at which auxiliary fuel is crushed by the impact when reaching the charging surface increases significantly. It is easy to lose the function as the original fuel.

Next, there is a drawback that it is very difficult to perform the layer height measurement of the material in the furnace because the distance from the free board portion to the upper surface of the material layer in the furnace is too far in terms of the measurement of the layer height of the material in the furnace.

When the free board part is high temperature, it is installed directly on the upper surface of the layer, so it is very difficult to measure the layer height of the material in the furnace through the free board part. Cutting and so on. In addition, even in remote measurement by electromagnetic waves, the distance to the measurement surface is far, and thus the accuracy or stability of the measurement is remarkably decreased, and since the deposits grown in the furnace are measured at the height of the floor, a stable floor height measurement cannot be performed. to be.

Next, the operation method of a gasification melting furnace is demonstrated.

An example of the apparatus configuration for implementing the conventional working method is demonstrated with reference to FIG. This is a vertical waste gasification furnace with a fluidized bed at the top and a moving bed at the bottom.

In the smelting furnace, air is mainly supplied from the main tuyeres, oxygen is added as necessary, and is supplied to the lower part of the furnace, a high temperature region (1600 ° C. or more) is formed in the lower part of the moving bed of the sedimentary layer, and the incombustibles of the waste are melted.

In addition, air is supplied from the auxiliary tuyeres to the fluidized bed by adding oxygen as necessary, the fluidized part is formed on the fluidized bed, and the waste is smoothly supplied to the lower part by drying and distilling the waste.

Subsequently, the air is supplied from the third tuyeres, the production of dioxins is suppressed by maintaining the temperature of the free board portion at a high temperature (1000 ° C. or higher), and the use of the product gas (by a gas turbine or the like) is easy by decomposing tar powder. Is letting go.

In the melting furnace as described above, in the case of changing the properties (heating amount, moisture content, etc.) or throughput of the waste and increasing the blowing amount, the temperature in the bed increases as time passes because the blowing from the auxiliary tuyeres is only air and oxygen. On the other hand, if the air flow rate of the auxiliary tuyeres is reduced, the air column speed becomes lower than the flow start speed, so that the flow of the upper portion of the sedimentation layer is impossible, so that the temperature of the fluidized bed portion cannot be lowered by reducing the air volume.

In addition, a high temperature portion is generated at the tip of the auxiliary tuyeres, and the non-flammable portion of the waste in the portion melts and grows on the furnace wall. Thereby, there exists a problem that waste becomes hard to move to the lower side of a brazier, and is in a state like a shelf.

According to the present invention, as a result of examining the above situation, it is possible to supply waste and subsidiary materials without going through the free board part, and also to enable the gaseous melting furnace to measure the layer height of the lower filling layer of the furnace just below the furnace. It is an object of the present invention to provide a working method of a gasification melting furnace that lowers the structure and the temperature and CO / H ₂ ratio of the flow portion.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of embodiment of the furnace body structure of this invention.

Fig. 2A is a graph showing an example of work data in the conventional furnace body structure.

2B is a graph showing an example of working data by the furnace structure of the present invention.

3 is a cross-sectional view of a conventional furnace body structure.

4 shows an example of an apparatus for implementing the method of the present invention.

5 is a diagram showing the configuration of an apparatus for implementing a conventional method.

The furnace structure of the gasification furnace of the present invention does not overlap the central axis of the gasification furnace free board part by more than 50% of the internal diameter of the furnace from the lower center axis of the furnace to supply waste and subsidiary materials without passing through the freeboard part or the layer of the furnace bottom filling layer. It is characterized in that the height measurement can be performed.

The furnace structure of the present invention is made based on the following aspects. Until now, a free board portion for improving gas properties has been preferentially installed above the filling layer, rather than an apparatus for performing a stabilization operation. However, experiments confirmed that the stabilization work of the furnace should be prioritized over the improvement of the gas properties, and the gas properties can be improved downstream, and the effect of this does not change even if the free board is installed so that it does not overlap from the center of the furnace. It became.

Therefore, as shown in FIG. 1, the central axis of the free board part is installed so as not to overlap more than 50% of the internal diameter of the furnace from the lower center axis of the furnace in order to improve feeding and measuring. As for the width | variety which does not overlap, about 50% of a furnace internal diameter is preferable, and even if it installed so that it may not overlap further, there was no big difference in the effect.

By installing the free board so that it does not overlap from the central axis of the furnace, input of waste and the like can be carried out from the central axis of the furnace, and raw materials, etc. can be charged evenly in the furnace, so that the mixing of the melt and the melt component adjusting material is effective. Since the melting point of the melt can be controlled, the melt can be discharged stably.

In addition, in the present invention, the measurement of the height of the layer does not pass through the high-temperature free board, so that it is measured by contacting the superimposed wire to the upper surface of the layer having a relatively low temperature. Therefore, it can measure stably.

Stable work is achieved from these.

Next, the structure and operation of the furnace structure according to the present invention shown in FIG. 1 will be described in detail in comparison with the conventional furnace structure shown in FIG. 3.

In a conventional furnace, a free board is provided directly above the filling layer, and waste and the like have been introduced from an oblique upper side of the furnace. However, a non-uniform distribution of the charges occurs in the furnace, such as falling to a position immediately before the inlet or being placed at the face of the inlet according to the specific gravity of the charge, and the melted residue and the ash and the melt component adjusting material are not sufficiently mixed so that the melt component It became uneven, and melting | fusing point or viscosity of a melt changed and it was not able to carry out stable melt discharge.

2 shows the progress of the work test of (a) by the conventional furnace body structure and (b) by the furnace body structure of the present invention.

In the conventional structure, although the waste throughput or auxiliary fuel input is almost constant, the discharge of the melt fluctuates as the melt component (base degree) is unstable and the melting point and viscosity change, and thus cannot perform a stable operation. Here, basicity is generally used as an indicator of the components of the melt and is expressed in weight percent of CaO / SiO ₂ .

On the other hand, the free board is installed so as not to overlap 50% horizontally, and the operation is performed by placing the inlet just above the upper surface of the floor (b), the charges are distributed evenly with respect to the central axis of the furnace, and the residues and ashes melted and As a result of improving the mixing of the melt component modifier (ash), the discharge of the melt was stable as a component of the theoretical value.

Next, the work data also confirmed that there was little generation of dioxins or tars in the conventional gas phase, and that the effects of the free board portion did not change from those in the prior art.

In addition, because the charge surface temperature is about 700 ° C., the layer height measurement by the overlapping wire was performed without cutting or stretching the wire. In addition, although the measurement by the microweb was performed as a remote measurement by electromagnetic waves or the like, the measurement was stable because the measurement distance was close and obstacles were hardly generated in the middle.

As a result, stable operation was achieved by smooth discharge of the melt and accurate bed height management.

The working method of the gasification melting furnace of the present invention is a vertical waste gasification melting furnace in which the upper portion of the sedimentation layer of waste is a fluidized bed and the lower portion is a moving bed, while controlling the temperature of the fluidized portion of the fluidized layer, The amount of the primary blowing air is controlled to maintain the flow state, and the temperature of the flow portion is controlled by adding steam, combustion exhaust gas and oxygen alone or in combination to the blowing of the auxiliary tuyeres.

In addition, the temperature of the flow portion of the fluidized bed is characterized in that it is controlled to 500 to 1000 ℃.

As in the prior art, increasing the amount of air blown from the auxiliary tuyeres to maintain the flow of the upper part of the sedimentary layer raises the temperature of the flow part and causes the melt to adhere to the furnace wall so that the shelf hangs.

On the other hand, if the amount of air flow is reduced to lower the temperature of the flow part, a sufficient amount of gas is not obtained, and the flow of the sediment bed or the flow of particles in the raceway in front of the auxiliary tuyeres becomes insufficient, and a high temperature part occurs in front of the tuyeres, resulting in waste The incombustibles melt and grow around the auxiliary tuyeres.

Therefore, in the present invention, steam, combustion exhaust gas and oxygen are added to the blowing of the auxiliary tuyeres alone or in combination.

In this way, the amount of blowing required to maintain the flow state can be ensured and the blowing oxygen concentration can be adjusted, thereby maintaining the proper flow in the sedimentation layer and controlling the temperature of the flow portion.

In this case, changing the oxygen concentration is equivalent to changing the amount of oxygen to be blown, and further, changing the amount of heat generated in the layer. In addition, when water vapor is used, a shift reaction (CO + H ₂ O → CO ₂ + H ₂ ) occurs to lower the value of CO / H ₂ of the generated gas, which is easy to use as a fuel such as a gas turbine.

The configuration of an apparatus for implementing the method of the present invention will be described with reference to FIG.

Air is supplied from (Va1) to the main blower in the lower part of the furnace, and oxygen is supplied from (Vo1). In this case, the amount of oxygen added to the blower of the main blower can be reduced by raising the blowing temperature to the main blower by the heater.

Next, air is supplied from (Va2) to the auxiliary tuyeres of the fluidized bed portion, steam is supplied from (Vs), and oxygen is supplied from (Vo2). Next, a thermometer for measuring the temperature of the flow portion is installed.

In addition, air is supplied to the third air vent of the free board portion from Va3. Next, an analytical system for analyzing the components of the product gas from the free board section is installed.

Subsequently, the amount of air at the main tuyeres is controlled by Va1 and the amount of oxygen is controlled by Vo1 depending on the throughput.

In addition, by controlling the blowing amount of the auxiliary tuyeres, the required air tower speed is obtained, and the upper part of the sedimentation layer is flowed.

Subsequently, the gas volume (air column speed) is divided into three classes, which are below the lower limit, within the reference value, and above the upper limit, and in the case where the fluidized bed temperature is 500 ° C. or less, more than 500 ° C., less than 1000 ° C., and 1000 ° C. or more. The action taken is shown in Table 1 below.

Gas volume Below the lower limit Within standard value Above the upper limit Fluidized bed temperature 500 ℃ or less Air: increase Air: * see Air: Decrease (Rate Constant) Steam: Stay steam: ' Steam: Decrease (Ratio Constant) Oxygen: Stay Oxygen: ' Oxygen: Decrease (Rate Constant) More than 500 ℃ Less than 1000 ℃ Air: increase By air: AS Air: Decrease (Rate Constant) Steam: Stay Steam: Stay Steam: Decrease (Ratio Constant) Oxygen: Stay Oxygen: Stay Oxygen: Decrease (Rate Constant) More than 1000 ℃ By air: AS Air: (decrease) Air: Decrease (Rate Constant) Steam: (increase) Steam: 〈Increase〉 Steam: Decrease (Ratio Constant) Oxygen: reduced Oxygen: reduced Oxygen: Decrease (Rate Constant) If the air flow rate of oxygen reaches 0, carry out the (), and if the air flow rate reaches 0, carry out 〈〉. * ① The amount of steam within the range of the maximum theoretical flame temperature of 2750 ° C or less. ② Reduces the proportion of air, oxygen and steam blowing.

Next, an Example is shown in Table 2 below.

Example Number 1-1 1-2 1-3 1-4 1-5 2-1 2-2 2-3 2-4 2-5 Auxiliary blower air volume Nm ³ / h 1245 1300 1300 1265 820 3090 3235 3030 2860 2030 Auxiliary blower oxygen amount Nm ³ / h 0 0 0 0 105 0 0 37 70 230 Amount of steam kg / h 0 0 117 35 400 0 0 0 110 660 Fluidized bed temperature ℃ 1000 1045 1000 1000 1000 440 500 500 500 500 Gas CO / H ₂ - 0.73 0.78 0.61 0.68 0.44 1.04 1.06 1.06 0.95 0.61 Generated gas calorific value kcal / Nm ³ drying 1000 960 910 970 915 1430 1390 1430 1410 1360 Tower speed m / s 2.0 2.1 2.2 2.0 2.2 2.7 3.1 2.9 2.9 2.9

Example 1 is a case where a fluidized bed temperature is 1000 degreeC or more, and Example 2 is a case where it is 500 degrees C or less.

Example 1-1 is a case where the gas amount (air column speed) is insufficient, and in Example 1-2 in which the auxiliary tuyer air amount is increased, the fluidized bed temperature becomes too high. Therefore, steam was added to the auxiliary tuyeres in Examples 1-3 to bring the fluidized bed temperature to an appropriate value. As a result, the value of CO / H ₂ was also improved to about 0.6.

Example 1-4 is a case where the amount of air is reduced at the same time as the steam in the auxiliary tuyeres.

In Example 1-5, to further lower the value of CO / H ₂ , the amount of steam was increased and oxygen was added, while the amount of air at the auxiliary tuyeres was reduced. As a result, the value of CO / H ₂ was further lowered, making it easier to use as fuel.

In addition, when the amount of gas (air column speed) is insufficient, combustion exhaust gas may be added to the air of the auxiliary tuyeres to increase the amount of gas while avoiding the increase in the fluidized bed temperature.

Next, Example 2-1 is a case where the fluidized bed temperature is lowered, and in Example 2-2, the amount of auxiliary tuyeres air is increased. As a result, the fluidized bed temperature rose, and at the same time, the amount of gas (air column speed) increased excessively.

Further, in Example 2-3, the amount of auxiliary tuyeres air was reduced while oxygen was added. As a result, the fluidized bed temperature and the amount of gas (air column speed) became appropriate values.

Example 2-4 added steam while simultaneously adding oxygen to lower the value of CO / H ₂ , while reducing the amount of air. In Example 2-5, in order to further improve the value of CO / H _2, the amount of steam and oxygen was increased while the amount of air was reduced.

As described above, it is possible to stably mix the melt and the melt component adjusting material and measure the height of the bed by the furnace structure of the gasification melting furnace of the present invention. The effect of lowering the temperature of the flow portion by adding and lowering the CO / H ₂ ratio was obtained by adding steam.

Claims (1)

The free board part of the gasification furnace does not overlap more than 50% of the inner diameter of the furnace from the lower center axis of the furnace, so that waste and subsidiary materials can be supplied without going through the free board, and the floor height measurement of the furnace bottom filling layer is directly above the bottom of the furnace. Furnace structure of a gasification furnace, characterized in that it can be carried out.