JPH05288316A - Waste material melting furnace - Google Patents

Abstract

PURPOSE:To restrict dust dispersion even in cause of a poor aeration waste material, perform a stable melting processing and improve a preheating and drying effect for discharged gas by a method wherein an inner surface of a furnace ranging from a part above a tuyere to a lower end of a charging cylinder is formed to be a substantial cylindrical shape. CONSTITUTION:Cokes charged from a peripheral cokes loading port 6 form a cokes charging region 11. A heat exchanging operation is carried out with combustion gas discharged from a discharged gas discharging port 7 while being dropped in a furnace, the cokes gradually increase their temperatures and reach an upper stage tuyere 2. A peripheral wall side at this location has a cylindrical shaft part 8, the ascending gas keeps its uniform flow at its circumferential direction with the metered ring-like cokes layer formed at the shaft part 8 and then its flowing speed is made fast. With such an arrangement, even in case of the waste material having a poor aeration characteristics, dust dispersion can be restricted, aeration characteristics in the furnace can be kept, a loading descending can be assured and at the same time the stable melting process can be carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to municipal solid waste, various industrial wastes, or intermediate products obtained by drying, incineration, crushing, etc., using a lumpy carbonaceous combustible substance such as coke as a heat source. The present invention relates to a waste melting furnace that heats and melts and recovers as a civil engineering material, a concrete fine aggregate, and a slag material for a surface makeup aggregate.

[0002]

2. Description of the Related Art Conventionally, in this waste melting furnace, the waste is charged from a basicity adjusting agent such as limestone and silica stone, coke, and the top of the shaft furnace, and oxygen-containing gas or oxygen is fed from the tuyere. Injecting an enriched gas into the furnace and burning carbonaceous matter produced by coke and pyrolysis at a high temperature in the high-temperature hearth at a high temperature. The drying zone, carbonization gasification zone, and combustion melting zone in the furnace are sequentially lowered and melted. The slag is turned into high temperature combustion exhaust gas,
There is a structure in which the waste packed bed in the shaft rises as a counterflow, becomes a combustible gas, is discharged, and is recovered as combustion heat.

The applicant of the present application has previously filed Japanese Patent Application Laid-Open No. 2-3328.
In the No. 85 application, a tuyere is provided at a lower portion of a furnace body in which an upper portion is enlarged and an inner surface is formed at an angle of repose or more of a charged lump carbon fuel, and a tap hole is provided at a position lower than the tuyere. From the top of the center, insert a cylinder for charging waste, lump carbon-based fuel and basicity adjuster so that its lower end reaches a position higher than the tuyere level. We applied for a waste melting furnace that has a charging port and discharges combustion gas from above. As a result, the massive carbonaceous fuel, which is a heat source, can be reliably supplied to the high-temperature hearth below the waste packed bed, and the tuyere at the lowermost stage is provided at the lower part of the cone with a small inner diameter. Air for forming the hearth or air enriched with oxygen can be reliably reached to the core, and a high-temperature hearth can be reliably formed.
A melting furnace with good operation efficiency can be obtained.

Further, in a waste melting furnace having such a furnace body, a space region is formed above a filling region of massive carbonaceous fuel that encloses a waste filling region formed above a high temperature region of the hearth. Therefore, a melting furnace that prevents deterioration of air permeability and unloading of lump carbon fuel due to mutual adhesion of lump carbon fuel by dust is also proposed.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to an improvement of such a waste melting furnace, in which waste having poor air permeability is stably melted while suppressing dust scattering, and preheat drying of exhaust gas. It is intended to provide a waste melting furnace with high thermal efficiency by improving the effect.

[0006]

According to the present invention, a tuyere is provided at a lower portion of a furnace body in which an upper portion is enlarged and an inner surface is formed at an angle equal to or greater than an angle of repose of a charged lumpy carbonaceous fuel, and a tuyere is provided at a position lower than the tuyere. A tap hole is provided at the upper part of the furnace body, and a charging cylinder for waste, lumpy carbonaceous fuel, and basicity adjusting agent is inserted from the upper center of the furnace body so that its lower end reaches a position higher than the tuyere level. In a waste melting furnace in which a lumpy carbonaceous fuel inlet is provided around the furnace, and the combustion gas is discharged from above, the inner surface of the furnace from above the tuyere to the lower end of the charging cylinder is formed into a substantially cylindrical shape. Characterize.

[0007]

The high-temperature exhaust gas from the high-temperature zone of the hearth at the lower part of the furnace is forced to flow near the waste packed bed because the furnace body in the packed area mainly composed of waste is narrowed down into a cylindrical shape. Therefore, the high-temperature exhaust gas promotes preheat drying of the waste.

[0008]

FIG. 1 shows an embodiment of the present invention, in which the charging system is shown by a solid line and the exhaust gas system is shown by a broken line.

The waste melting furnace 10 has an inner upper surface with an inclination angle of 7
It has a furnace body 1 formed wide at 0 degrees. Two stages of tuyeres 2 and 3 are provided on the lower peripheral surface of the furnace body 1, and a melt tap 4 is provided below the tuyere 2. A charging cylinder 5 for charging a charge mainly composed of waste is inserted from above the center of the furnace body 1, and coke charging ports 6 are formed at a plurality of locations on the outer periphery of the furnace body 1. An exhaust gas discharge port 7 is provided in the middle. Between the lower end of the charging cylinder 5 of the furnace body 1 and the upper tuyere 2, a shaft portion 8 having a substantially cylindrical inner surface of the furnace body is formed.

When operating this waste melting furnace 10,
From the waste charging cylinder 5, as shown by the charging system shown by the solid line in the figure, the waste A, the central coke B of 40 to 80% by weight of the total coke B, and the limestone C as a basicity adjusting agent. Filled with a mixture of 9 and the waste filling area 9
Is formed. Further, a block coke having a diameter of 2 to 80 mm is charged from the coke charging port 6 around the furnace, and a coke charging area 11 of the charging coke is formed around the charging area 9 mainly containing waste, and Space area 1 above
Form 2.

The coke charged from the peripheral coke charging port 6 forms a coke filling area 11 where heat exchange is performed while descending with the combustion exhaust gas discharged to the exhaust gas discharge port 7, and the coke is gradually increased. Part of the CO gas in the combustion exhaust gas that rises from below when reaching the upper tuyere 2 is preferentially combusted, and the resulting heat heats it to a higher temperature and blows in oxygen. Part of this burns the coke distributed around the inside of the charging cylinder.

At this portion, softening and melting of ash and incombustibles have started and it is relatively difficult for the ascending gas to pass through, but the peripheral wall side has a shaft portion 8 formed in a cylindrical shape. By the narrowed ring-shaped coke layer formed on the shaft portion 8, the rising gas maintains a uniform flow in the circumferential direction, and the flow velocity is increased, and the rising gas also passes through the waste filling area 9. This promotes heat transfer.

The charging coke is burned by the air from the upper tuyere 2, and 700 to 10 is provided at the lower center of the charging cylinder 5.
A high temperature furnace in which the temperature reaches 00 ° C and the center coke of the coke supplied to the charging cylinder by the preheated air blown from the lower tuyeres 3 is also uniformly burned to stably maintain the high temperature coke grate. A floor 13 is formed. The charged coke becomes red hot coke by the time it reaches the high-temperature hearth 13, and ash and non-combustibles rapidly soften and melt the voids of the grate of the coke by the radiant heat and high-temperature combustion exhaust gas resulting from the combustion of the coke, and then exit. It is extracted from the sprue 4.

Further, in the exhaust gas E discharged from the exhaust gas discharge port 7, the amount of entrained dust is reduced due to the formation of the space area 12, and the secondary combustion chamber 14, the air preheater 15, and the secondary combustion chamber 14 are passed through the system shown by the dotted line. Further, it is discharged into the atmosphere through a purifier (not shown). Reference numeral 16 denotes a forced air blower for blowing the air preheated by the air preheater 15 to the tuyere 2, 3.

[0015]

The present invention has the following effects.

(1) A high-temperature hearth is reliably formed, and even a waste with poor air permeability can be stably melt-processed while suppressing dust scattering and maintaining air permeability and unloading in the furnace, and preheating with exhaust gas. A waste melting furnace with high thermal efficiency can be realized by improving the drying effect.

(2) Since the charged waste is sufficiently preheated, the fuel cost can be reduced.

(3) By passing the exhaust gas generated from the high-temperature hearth through the massive fuel area around the waste-filled area with good air permeability, dust scattering from the waste can be minimized, and
The dust that has once scattered is also captured in the process of passing through the packed bed of the agglomerated carbon-based fuel, and it is possible to suppress the accompanying dust, stabilize the gas flow in the furnace, and enable stable operation of the furnace.

[Brief description of drawings]

1 shows an embodiment of the invention with a charging system and an exhaust gas system.

[Explanation of symbols]

1 furnace body 2, 3 tuyere 4 tap hole 5 waste charging cylinder 6 coke charging port 7 exhaust gas discharge port 8 substantially cylindrical shaft part 9 waste charging area 10 melting furnace 11 coke charging area 12 upper space area 13 high temperature Hearth 14 Secondary combustion chamber 15 Air preheater 16 Push-in blower

Front Page Continuation (72) Inventor Shunji Tsukazuka 46-59, Nakahara, Tobata-ku, Kitakyushu, Fukuoka Prefecture Machinery & Plant Division, Nippon Steel Corporation (72) Kunihiro Watanabe, Nakahara, Tobata-ku, Kitakyushu, Fukuoka Prefecture 59, Nippon Steel Plant Design Co., Ltd.

Claims (1)

[Claims] 1. An enlarged upper part, the inner surface of which is formed at an angle greater than or equal to the repose angle of the charged lumped carbonaceous fuel, a tuyere is provided at a lower position, and a tap hole is provided at a position lower than the tuyere. Insert the waste, lump carbon fuel and basicity adjuster charging cylinder from the upper part so that the lower end reaches a position higher than the tuyere level,
In a waste melting furnace having a furnace structure in which a charging inlet for massive carbonaceous fuel is provided around the charging cylinder, and an exhaust gas outlet is provided above the charging furnace, from the upper end of the tuyere to the lower end of the charging cylinder. A waste melting furnace characterized in that the inner surface of the furnace is formed into a substantially cylindrical shape.