DE1796057C3 - SHACHT OVEN heated with gasified oil - Google Patents

Description

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The invention relates to a shaft furnace according to the preamble of the patent claim.

Such a shaft furnace is by the magazine "Zement-Kalk-Gips", 1966, No. 2, pages 53 and 54, known. In this known shaft furnace, two horizontally extending distribution pipes are provided which are arranged on opposite broad sides of the combustion zone at the same height. From the manifolds branch lines go out. which lead to a total of 16 outlet openings in the combustion zone, whereby 8 outlet openings are arranged in a common horizontal plane, 8 of them Outlet openings are formed in each broad side 4 and the outlet openings are in a horizontal plane facing on both broad sides. The oil gasification burner device consists of an oil gasification burner, which feeds both distribution pipes. The preheating zone has initially above the burning zone constant cross-section and then expands upwards.

By means of the known shaft furnace, it is not possible to selectively achieve a certain degree of firing; rather, it is only able to deliver a mixture of soft fires. In addition, the known Shaft furnace high maintenance costs, as the distribution pipes and branch lines tend to form soot.

A certain, selected degree of firing can be achieved with a rotary kiln. Such a rotary kiln has however, high investment costs and in particular a high specific energy consumption.

It is known from the book "Das Kalkbrennen" by G. Block, 2nd edition, 1924, pages 166 and 167 (in particular Figure 5e and associated text), in the case of a cylindrical shaft furnace to increase the Capacity to arrange opposite outlet openings offset in height. Furthermore, it is over the same book known (in particular page 245, paragraph 1, and page 248, paragraph 5), to avoid the The preheating zone should be designed to be slightly conical in order to fix the descending charge.

The invention is based on the object of designing a shaft furnace of the generic type in such a way that it is easy and economical to manufacture and requires little maintenance, while at the same time having a high thermal efficiency should be achieved.

According to the invention, this object is achieved by the features in the characterizing part of the patent claim solved.

The design according to the invention ensures that the cross-section of the combustion chamber is as identical as possible Temperature conditions, the same flow rates of air and fuel, as well as the same Sinking speeds of the material used and the same as possible over the height of the combustion chamber Establish conditions, being targeted at the conditions in the individual areas of the burn zone can be acted upon. This creates the prerequisites for the most uniform possible quality of the fired material and thus to generate a specific degree of firing in a targeted manner.

Due to the uniform flow and temperature conditions in the combustion chamber as well as the intensive The shaft furnace according to the invention can mix fuel and secondary air with extremely little Excess air are operated. This leads to a small amount of flue gas and low exhaust gas temperature, what in turn results in high thermal efficiency and high economic efficiency.

Finally, it reduces the lack of long branch lines and manifolds between the manifolds and the oil gasification burner device the maintenance effort, since all lines downstream of the Oil gasification burner equipment should be cleaned regularly because of the risk of clogging by soot have to.

An embodiment of the invention is shown in the drawings and will be described in more detail below explained. It shows

Fig. 1 is a schematic representation of the front view a shaft furnace according to an embodiment of the invention,

Fig. La, on an enlarged scale, the arrangement of an oil gasification burner according to detail E in Fig. 1,

2 in section along the line AA in FIG. The shaft furnace according to Fi g. 1 and

Fig. 3 graphically shows the temperature in Interior of the shaft furnace according to FIG. 1.

Fig. 1 shows in a simplified and schematic way an embodiment of a shaft furnace 1 according to the invention, which is placed on the substructure 2.

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As usual, the shaft furnace is charged from above with the raw material, for example limestone, which then falls through the preheating zone V , undergoes its chemical conversion into quick lime in the combustion zone B , through the subsequent cooling zone K down into the filling funnel 3, cf. also Fig.2, and from there continuously or periodically by means of conveyor belts, not shown. The like. Is passed on.

The chemical conversion, for example the limestone into quick lime according to the formula CaCG ₃ = CaO + CO ₂ , at which a temperature of 900 to 1200 ⁰ C must prevail, takes place in the actual combustion zone B, the thermal energy required for this endothermic conversion process being essentially by combustion of the gas flowing into the combustion zone B , such as gasified oil or the like, is applied.

According to the embodiment of the invention shown in Fig. 1, each distributor pipe 5 to 8 is supplied via a separate oil gasification burner 10 to 13, in which gasified oil with a temperature of about 900 to 950 ^° C. to 8 and their outlet openings 9, 9a passes through into the combustion zone B. The oil supply lines for the individual oil gasification burners 10 to 13 are denoted by 10a to 13a. The separate air blowers 14, 14a, 15, 15a for generating compressed air or for regulating or controlling the combustion in the oil gasification burners 10 to 13 are connected to the individual oil gasification burners 10 to 13 via lines 16 to 19.

In Fig. La, the arrangement of the supply line 10a for the oil and the line 17 for the compressed air are on the oil gasification burner 10 and its distributor pipe 5 can be clearly seen.

In order to maintain an almost uniform temperature - which should be between 950 and 1200 ⁰ C for lime burning - in the entire relatively high combustion zone B , the gasified oil is supplied in the illustrated embodiment of the invention via four distributor pipes 5 to 8, which alternately, see also Fig. 2, are arranged on opposite sides of the shaft furnace 1 at the combustion zone B and are also vertically offset from one another. To increase for the same reason, namely by the uniformity of the temperature over the entire width of the combustion zone B, 8 open the Verteilerrrohre 5, 7 and 6, with a partially mutually offset outlet openings 9 and 9a in the combustion zone B.

To compensate for the inevitable temperature gradient in the distribution pipes of about 50 to 80 ⁰ C are the oil-combustor 10, 11 and 12, respectively, mounted on opposite sides of the shaft furnace to the distributor pipes 5.6 and 7.8. 13

The air introduced into the cooling zone K from below by means of the air blower 21 through appropriate lines 22, 23 and inlet openings 23a for cooling the end product, such as quick lime, is dimensioned so that it is just for complete burning of the from the distributor pipes 5 to 8 Gasified oil flowing into combustion zone B is sufficient.

About thermocouples 24 to 27 arranged in a distributed manner in the combustion zone, see FIG. 2, the temperature is measured at various points and via a ^{control device (not shown)} on the individual oil gasification burners 10 to 13 or on their

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65 oil supply devices and transferred to the fans 14, 14a, 15, 15a, whereby the supplied fuel and compressed air quantities as well as the temperature of the gasified oil in the individual distribution pipes 5 to 8 are independent of each other, but depending on the optimal temperature in the combustion zone B automatically controlled or regulated.

In this way it is possible to achieve a uniform temperature in the entire firing zone, although as a result of the air entering the combustion zone from below, an Luftbzw in its lower section. There is an excess of oxygen and, moreover, precisely there the endothermic chemical conversion process - For example of lime in quicklime - is almost complete, so that there the Energy requirement is lower

The hot gases produced during the burning process, such as CO ₂ gas, are diverted through the preheating zone Vhindurch directly upwards and leave the shaft furnace 1 via the chimneys 4 at a relatively low temperature of around 100 to 150 ° C.

As in Fig. Indicated by dashed lines 1, however, is seen more clearly in Figure 2, the preheating zone V tapers stepwise from the combustion zone S to the hopper 20, whereby the so-called bridging of the advancing rock due to heating and chemical processes prevented.

This simple structural measure enables continuous operation of the system according to the invention Shaft furnace for months and years.

Furthermore, in FIG. 2 the lateral, vertically offset arrangement of the distribution pipes 5 to 8 can be seen.

In Fig. 3 the temperature in a shaft furnace 1 for burning lime according to the invention is shown graphically. The temperature in the combustion zone B is between about 900 ⁰ C and 1220 ⁰ C is adapted to the requirements of lime burning, while the respective requirements can be easily adapted when burning other materials by adjusting the oil gasification burner 10 to 13 or the control or regulating device.

Furthermore, indicates the low extraction temperature of about 60 ° for the quick lime as well as the relatively low exhaust gas temperature of 100 to 150 ° with the method according to the invention achieved high thermal efficiency.

According to the present invention, a surprisingly simple and therefore more economical one is made Shaft furnace for burning lime, magnesite, dolomite and the like. Proposed in which as a result of the entire height and width of uniform temperature in the firing zone, which is achieved with simple measuring and control devices can be kept automatically at the optimal value, enables fast work and rejects - for example as a result of sintering due to temperatures that are too high in places - is avoided.

Furthermore, in the shaft furnace according to the invention, there are no lines for recirculating gases required, but only the distribution pipes carrying the gaseous fuel and the pressure lines available, which are under overpressure and are therefore not subject to dust formation. Through this the maintenance of the shaft furnace is considerably simplified and cheaper and, since also bridging the Rock in the preheating zone is prevented

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Continuous operation for months and years enabled.

Since, on the one hand, the amount of heat absorbed by the cooling air in the cooling zone K reduces the energy requirement in the combustion zone and, on the other hand, the hot exhaust gases transfer their heat to the starting material in the preheating zone, the overall thermal efficiency of the shaft furnace according to the invention is far above what was previously possible with justifiable expenditure achievable values.

For this purpose 2 sheets of drawings

Claims (1)

Claim: Shaft furnace heated with gasified oil for burning lime, magnesite, dolomite or the like, with a cooling zone into which air is blown from below, a combustion zone with a rectangular cross-section and a preheating zone following the combustion zone, with several horizontally running distribution pipes for supplying the gas Oil to the combustion zone, which are arranged on both sides of the combustion zone and open into the combustion zone with outlet openings at different heights, and with an oil gasification burner device that feeds the distribution pipes and which produces gasified oil as fuel by burning a portion of the supplied oil under a lack of oxygen, the temperature of the gasified oil in the distributor pipes is regulated or controlled to a value lying about 5 to 20% below the temperature in the combustion zone and the amount of fuel being controlled as a function of the temperature in the combustion zone, characterized by the combination of the features that 4 or 6 distribution pipes (5,6,7,8) are arranged in four or six different horizontal planes and alternately on opposite sides that the non-outer outlet openings (9, 9a) of the distribution pipes on the same side from one distribution pipe to the adjacent in the horizontal direction are offset from each other, that the preheating zone (V) tapers in cross-section stepwise or continuously upwards, that the oil gasification burner device consists of several oil gasification burners (10, 11, 12, 13), one of which is connected to each of the distribution pipes, that the oil gasification burners are arranged alternately on opposite sides of the shaft furnace and that each oil gasification burner is assigned its own controllable air fan (14,14a, 15, lSa ^.