JPS6011294B2 - How to operate a waste liquid incinerator - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of operating a furnace for incinerating waste liquid.

When industrial waste liquid, such as valve waste liquid, containing Na as a waste liquid composition is incinerated, Na2S0 is used as a combustion residue.
4. When Na2CQ, NaCI, etc. are produced to form a eutectic, the melting point thereof becomes low. Such eutectics are classified into two types: those that scatter as dust from the furnace outlet into the duct, and those that adhere to the furnace walls within the furnace and become so-called smelt that flows down to the lower part of the furnace. Smelt solidifies when the temperature drops, and its melting point is approximately 600 to 900 degrees Celsius.
It is. Therefore, in the combustion chamber where the atmosphere is above the flow temperature, the combustion chamber flows down the wall surface as smelt and flows down from the lower end of the furnace to the water dissolving tank and is discharged. When smelt is exposed to an atmosphere at a temperature lower than its pouring temperature, it solidifies and causes problems such as clogging of the furnace outlet. Because smelt has these properties, the residual grooves contained as soot and dust in the exhaust gas of an incinerator are in a molten state at a gas temperature above the melting point, and when the high-temperature exhaust gas containing this soot and dust is cooled with air, air is supplied. Usually, it adheres to the cooling nozzle parts and solidifies and accumulates, leading to clogging of the cooling parts including these nozzles. Therefore, in the technology for treating combustion residue, the structure and operation method of a waste liquid treatment furnace containing low-melting substances such as Na compounds are important issues. The object of the present invention is to propose a method of operating a waste liquid incinerator in which smelt does not adhere to the exhaust gas path of the waste liquid incinerator and cause blockage.

The structure of an apparatus according to the present invention will be explained with reference to the drawings.

In Fig. 1, the incineration chamber 1 is lined with refractory material 4,
The combustion burner 2 creates a high-temperature atmosphere of 900 to 1000 qo in the incineration chamber. The waste liquid is atomized and sent into the furnace in this high-temperature atmosphere by the waste liquid sprayer 3, and is incinerated. A portion of the combustion residue of the waste liquid is dispersed in the exhaust gas as molten droplets, but most of it adheres to the inner wall surface of the furnace and forms so-called smelt, which is then diluted into the constriction section 6.

As the combustion gas flows from the incineration chamber 1 to the throttle part 6, the cross-sectional area of the exhaust gas passage becomes smaller, so the gas velocity increases, which promotes the flow of smelt down the furnace wall surface, and the smelt that flows down is The residual liquid flows down to the water dissolving tank through the residual liquid outlet 5 and is dissolved.

However, the combustion residue in the form of droplets dispersed in the gas remains in a molten state and heads toward the exhaust gas outlet 11 along with the exhaust gas.
In order to recover such droplets of combustion residue in the exhaust gas as solid powder, it is necessary to cool them with air to below the melting point.
As shown in the figure, in the exhaust gas passage connecting the incinerator 1 and the exhaust gas outlet 11 and sloping downward, there is a first-stage cooling zone section that is a cooling zone section during normal operation and is composed of a plurality of nozzles 9 and an air outlet 7. It is formed. Cooling air is ejected from this nozzle 9 to cool and solidify the droplets in the exhaust gas, and the powder is collected by a dust collector (not shown) downstream of the exhaust gas. In this way, the droplets in the combustion residue groove are pulverized by contact with the cooling air and a drop in the temperature of the exhaust gas, but in the process, some of the droplets are pulverized near the nozzle before being accompanied by the airflow from the nozzle 9. It adheres to cold surfaces and solidifies.

This solidified and deposited combustion residual solution grows, forming a vortex of exhaust gas around this deposit, causing the deposit to grow near the nozzle 9, making the entrance of the nozzle 9 smaller, and finally blocking the nozzle 9. This makes it impossible to cool the exhaust gas. The occurrence of such deposition can be detected by a window (not shown) provided in the exhaust gas passage, a change in the pressure inside the furnace, or the like. Conventionally, the nozzle 9 was tried to be pushed in with a stick, but since solidified smelt is hard like concrete, it cannot be opened easily. In addition, installing a combustion burner or the like in the vicinity to melt and remove the deposits requires burner equipment, equipment for supplying combustion air, etc., which is undesirable as it requires an increase in the capacity of the wake-induced blower and an increase in maintenance. This device utilizes the high temperature of exhaust gas to propose a means for removing deposits from the nozzle portion without requiring a particularly complicated device.

The first stage cooling zone (composed of a plurality of nozzles 9 and air header 7) is used during normal operation of the incinerator.

Note that for the second stage cooling zone having the nozzle 10 and the air header 8, the first stage cooling zone becomes the upstream cooling zone. When cooling is no longer available, reduce the amount of cooling air to the air header 7 or stop supplying it, and supply cooling air to the header 8 of the second stage cooling zone. The exhaust gas will continue to be cooled and the incinerator will continue to operate. When such a second-stage cooling zone is in operation, more than 60,000 exhaust gases flow into the first-stage cooling zone, creating a high-temperature atmosphere in the vicinity, and the deposits that adhere and solidify there rapidly melt and dissolve in water. Flows down the oblique exhaust gas passage wall toward the tank side. When the deposits have been sufficiently removed from the nozzle 9, the first stage cooling zone is returned to the normal operating state, and the necessary cooling air is supplied from the air header 7, and the cooling air is supplied to the air header 8. Air supply is stopped. The time required to melt and remove this deposit is 30k9 as shown in Figure 2.
Since it only takes 1 hour and 30 minutes for the deposition of 1 hour and 30 minutes, it can be said that the combustion residue is almost never deposited in the vicinity of the nozzle 10 in the second stage cooling zone.

Also, after several months of continuous operation, nozzle 1 in the second stage cooling zone
0 is close to blockage, a third stage cooling zone (air header 12
(consisting of a plurality of nozzles) can be preliminarily provided to function as a downstream cooling zone.

By this operation, the exhaust gas cooling function of the second-stage cooling zone, which is the upstream cooling zone in this case, can be restored by creating a high atmosphere in the vicinity thereof.

Since the third-stage cooling zone has virtually no chance of losing its function, the first, second, and third stages, including the third, although it is hardly necessary, are This is done by providing sufficient opportunities for periodic inspection and cleaning.

In this way, it is possible to operate the incinerator continuously in correspondence with the continuous operation of the plant without stopping the operation of the incinerator. Figure 2 shows the relationship between the amount of deposits and the time required for melting.
The smelt deposition of k9 is about 7k9 in 1 hour, 1. In the period time (the dotted line is an estimated value by calculation), it becomes almost zero, indicating that it is removed.

By carrying out this invention, the incinerator attached to the plant can be operated continuously, without interfering with the operation of the plant, and without the need for a special burner device for removing deposits. It has exceptional effects such as ease of operation and maintenance of plants and incinerators, and cost savings.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a waste liquid incinerator according to the present invention, and FIG. 2 is a diagram showing the relationship between the amount of residual liquid and time for dissolving the residual liquid. 1... Incineration chamber, 2... Assist burner, 3... Waste liquid sprayer, 4... Refractory material, 5... Residue discharge port, 6...
Throttle part, 7... Air header of first stage cooling zone, Air header of second stage cooling zone, 9... Nozzle of first stage cooling zone, 10... Second Nozzle of the stage cooling zone, 11... Exhaust gas outlet, 12... Air header of the third stage cooling zone. Figure 1 Figure 2

Claims (1)

[Claims] 1. In a method of incinerating waste liquid in a furnace, when a plurality of cooling zones are provided in the exhaust gas passage from the furnace, and combustion residue adheres to and solidifies in the cooling zone on the upstream side of the exhaust gas flow among the multiple stages of cooling zones. In this case, the exhaust gas is cooled only by the downstream side cooling zone located on the downstream side of the upstream side cooling zone, and the combustion residue that has adhered and solidified on the upstream side is melted and the function of the upstream side cooling zone is restored. A method of operating a waste liquid incinerator characterized by cooling.