JPH0335578B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applied to seaweed that grows or collects near seawater intakes and drainage ports of thermal power plants, nuclear power plants, etc., and is regularly removed and collected. The present invention relates to a method for incinerating wet waste containing chlorine, such as chlorine-containing wet waste.

(Conventional technology) A large amount of seaweed grows near the seawater intake and drainage ports of power plants and is collected on screens, etc., obstructing the flow of water, so it is necessary to periodically remove it and collect it on land. . Conventionally, the seaweed collected in this way was buried within the site, but there is a gradual shortage of land for landfill, and the problem is that it rots and gives off a bad odor to the surrounding area. Attempts have also been made to incinerate the collected seaweed in an incinerator, but due to the chlorine in the seawater, hydrogen chloride gas is generated and the equipment is severely corroded, and the combustion temperature is low, resulting in unburned There were problems such as the generation of a large amount of carbon, which could cause a fire inside the filter, etc., and the generation of a strange odor.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, enables significant volume reduction by incineration, prevents corrosion of equipment due to hydrogen chloride, and This method was developed for the purpose of incinerating wet waste containing chlorine without emitting any strange odors.

(Means for Solving the Problems) The present invention dries wet waste containing chlorine using a hot air dryer with a dry exhaust gas temperature of 300°C or less, and introduces the dried waste into an incinerator together with the dry exhaust gas. It is incinerated at a temperature of 600℃ or higher and taken out as incineration ash, while the incineration exhaust gas is guided directly to a cooling air mixer through piping lined with refractory material, and the cooling air is mixed in the cooling air mixer to produce a 150 to 350 ℃, the cooled incineration exhaust gas is guided through austenitic stainless steel piping, and if necessary, dust is removed and discharged into the atmosphere using an induction fan.

The present invention will be explained in detail below with reference to illustrated embodiments. 1 is a rotary hot air dryer; 2 is a rotary hot air dryer;
is a hot air generating furnace, and wet waste containing chlorine such as seaweed is first charged into this hot air dryer 1 from a material bunker 3 and dried. The drying conditions are such that the drying exhaust gas temperature is maintained at 300℃ or less, preferably around 200℃, so that wet waste with a moisture content of approximately 85% by weight (hereinafter expressed in weight%) has a moisture content of 40%.
However, the temperature of the dried material is mostly 80℃, which is the wet bulb temperature of the dry exhaust gas, and even the part that does not contain any moisture is below 300℃, and the precipitated salt (NaCl) is dried at this temperature. It will not decompose and produce HCl gas. Next, the dried products are fed into an incinerator 6 via an intermediate hopper 5 by a dry product conveyor 4. On the other hand, the dry exhaust gas from the dryer is removed by a dust collector 7, and then a part is returned to the hot air generating furnace 2 by a circulation fan 8, and the other part is blown into an incinerator 6. Combustion air and high-temperature combustion gas are blown into the incinerator 6 by a combustion air fan 9 and a burner 10 at a temperature of 600°C or higher and 1000°C or lower, preferably 800°C.
It is incinerated at temperatures around ℃. The reason why the incineration temperature was set at 600℃ or higher was to completely decompose the odor generated during drying and make it odorless, and also to ensure good combustion and reduce unburned carbon in the incineration exhaust gas.
The reason for setting the temperature to 1000°C or lower is to prevent damage to the refractories on the inner surface of the incinerator 6. The waste thus incinerated in the incinerator 6 becomes incinerated ash, which is cooled by an ash cooling conveyor 11 and then transported to the outside via an ash conveyor 12 and an ash bunker 13. On the other hand, incineration exhaust gas containing hydrochloric acid gas generated by combustion is led to an air mixer 15 through a pipe 14 lined with a refractory material, where it is mixed with cooling air and cooled to 150 to 350°C. temperature is 150℃
Below this, the exhaust gas containing hydrochloric acid gas will reach the dew point and cause hydrochloric acid condensation, causing electrochemical corrosion in the piping. Furthermore, when the temperature exceeds 350°C, so-called high-temperature corrosion occurs due to the formation and decomposition of iron chloride or alkali iron sulfate. Therefore, in the present invention, the exhaust gas temperature is controlled within the range of 150 to 350℃, more preferably within the temperature range of 200 to 300℃ to prevent corrosion caused by hydrochloric acid gas, and the piping after this is made of austenitic stainless steel. It is possible to use metal piping with excellent corrosion resistance, such as The incineration exhaust gas cooled in this manner is removed by a dust collector 16, drawn by an induction fan 17, and discharged into the atmosphere from a chimney 18. Note that if a hydrogen chloride absorption device is provided in the middle of the piping 14, corrosion of the piping described below due to hydrochloric acid gas can be more reliably prevented.

With the equipment explained above, seaweed with a moisture content of 85% is transferred to hot air dryer 1 with an exhaust gas outlet temperature of 200°C.
Supplied at a ratio of Kg/Hr, dry matter with a moisture content of 40% is supplied.
Although it was obtained at a rate of 70Kg/Hr, no hydrogen chloride was detected in the dry exhaust gas. When such dried material was put into the incinerator 6 whose internal temperature was maintained at 800°C, the amount of incinerated ash generated was 10 kg/Hr, and the weight reduction ratio was 28 times of 280/10. In addition, the concentration of hydrogen chloride gas in the incineration exhaust gas at this time was 50 to 100 ppm, but when it was cooled to 300 degrees Celsius using the air mixer 15, no corrosion was observed in the subsequent piping, and it was released from the chimney 18. No abnormal odor was detected in the exhaust gas.

(Effects of the Invention) As is clear from the above explanation, the present invention can significantly reduce the volume of wet waste containing chlorine such as seaweed by incinerating it, making it possible to significantly reduce the volume of wet waste that contains chlorine, such as seaweed. The shortage can be resolved. Furthermore, according to the present invention, incineration is carried out at a high temperature of 600°C or higher, so there is no foul odor or large amount of unburned carbon, and the incineration exhaust gas is free from the risk of dew point corrosion or high temperature corrosion caused by hydrogen chloride gas. 150
Since it is cooled to a temperature of ~350°C, corrosion of equipment can be prevented. Therefore, the present invention is particularly useful for the development of industry as a method for incinerating wet waste containing chlorine, which is suitable for incinerating seaweed that grows or is collected in seawater intakes and drains of thermal power plants and nuclear power plants. The contribution made is extremely large.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing one embodiment of the process of the present invention. 1: Hot air dryer, 6: Incinerator, 15: Air mixer.

Claims (1)

[Claims] 1. Dry wet waste containing chlorine when the exhaust gas temperature is
Dry in a hot air dryer with a temperature of 300℃ or less, and introduce the dried material into an incinerator together with dry exhaust gas for 600℃.
While it is incinerated at temperatures above ℃ and taken out as incineration ash,
The incineration exhaust gas is guided directly to the cooling air mixer through a pipe lined with refractory material, and the cooling air is mixed in the cooling air mixer and cooled to 150 to 350℃. A method for incinerating wet waste containing chlorine, which is guided through stainless steel piping, removed as necessary, and discharged into the atmosphere using an induction fan. 2. The method for incinerating wet waste containing chlorine according to claim 1, wherein the incinerator has an incineration temperature of 600 to 1000°C. 3. A method for incinerating wet waste containing chlorine according to claim 1, wherein a part of the dry exhaust gas from the hot air dryer is recycled to the hot air generating furnace of the dryer.