DE2019078B2 - SIC-CONTAINING REFRACTORY STONE FOR BRINGING OUT DISCONTINUOUSLY OPERATED COOKING OVENS - Google Patents

Description

2

instead, however, they are also stronger and, for example, have a diameter of 80 mm. For reasons of thermal expansion It can also be useful that the brickwork of the unier building of the furnace chambers is created from the stones according to the invention.

In-depth investigations have shown that an increase in the thermal conductivity of the lining of coking ovens above a value of about 6.5 kcal / mh ° C for the coke fermentation process, is particularly detrimental to the quality of the coke. This is due to the fact that the thermal conductivity the coking coal and the coking products are not large enough to offer any large supply Absorb heat quickly enough. Rather, the heat requirement of the stove stones must correspond to the heat »Capacity must be adapted to the furnace filling. According to the invention, the thermal conductivity of the Brick lining, especially of the runner stones, a value of about 2.5 to 6.5 kcal / mh ° C, preferably 3 to 4 kcal, 'mh ° C.

As refractory bricks, which are particularly suitable for carrying out the lining according to the invention, runner and binder bricks come into question, which are 40 to (> 5 _{%) made of Al 2} O ₃ , otherwise from 35 to 60% SiO ₂ and oxides of trace elements exist and additionally 10 to 45 preferably 20 to 40 contain ° / ₀ ° / ₀ silicon carbide. in industrial trials have already confirmed that this stone material both heizzugseitig and the chamber side to the loads occurring in coke ovens with a discontinuous operation., in particular also withstands the effects of oxygen, but also of solid carbon, steam and gaseous carbon dioxide.

The one with the! The advantages that can be achieved by the invention are in particular that the cooking times of the coke can be shortened considerably * in the discontinuous operation of the coking ovens. This works without the To increase heating flue temperatures, because the over the heating flues the runner stones and over this the The amount of heat supplied is fully utilized. The achieved increase in throughput the! coking furnace is therefore large with the same heat supply.

The following table shows the previous data for assessing the value of a 40% SiC brick, especially for coke oven operation.

078

Refractory brick with
40 ^ü / "SiC

MgO,% 0.08

SiO ,,% 24.5

Fe ₂ O ₃ ,% 0.3

Al ₂ O ₃ ,% 36.4

SiC,% 39.0

Pressure fire resistance around 1820

Thermal conductivity

at 500 "C, kcal / mh ° C 4.5

at 1000 ⁰ C, kcaI / mh ° C 4.2

at 1400 ⁰ C, kcal / mh ° C 4.0

Thermal expansion

at 500 ^° C.,% 0.2

at 1000 ⁰ C, ° / o ° ' ⁵

at 1400 ⁰ C, ° / ₀ 0.65

Density, g / cm ³ 2.5

Porosity,% 9 to 11

Cold compressive strength, kg / cm ² 400 to 500

The drawing shows a plan view of a horizontal section through two different heating flues Design type. The numbers 1 denote in the F i g. I and II the so-called runner stones, which are at the same time Form one wall each for the coke oven chamber adjoining it on the right and left. Number 2 denotes the Binder that support the heating train building. The shapes of the stones according to FIG. 1 and II are, as can be seen, different. Such different forms are known and not immediate subject of the invention. As you can see, the stones are held together by tongue and groove. The joints between the stones are filled with refractory binders.

example

A furnace chamber with a chamber width of 450 min was lined with refractory bricks with an addition of 40% silicon carbide from the table above with a wall thickness of 58 mm. In this chamber a coking coal 24.8% volatiles (9% water content) was coked at a Heizzugtemperatur of 1300 ⁰ C. The fermentation of the coke was completed after just 7 hours. The coke that was printed and erased still contained 0.06% volatiles.

1 sheet of drawings

Claims (2)

In addition, from the Didier-Taschen patent claims: calendar 1967, p. 29, silicon carbide bricks are known that according to their intended use with a 1. SiC-containing refractory brick with a content between 40 and 90% silicon carbide in the thermal conductivity of 2.5 to 6.5 kcal / mh ° C, 5 trade. However, these stones must not be used at a rate of preferably 3 to 4 kcal / mh ° C, for the lining of an oxidizing furnace atmosphere. The thermal conductivity of a 90% SiC brick, which is operated discontinuously, is, for example, 13 to 15 kcal / mh ° C, especially as runner and binder stones. Also from the period characterized by the fact that the publication "Gießereipraxis", 1958, p.478, it is known to add stones in addition to "10 to 45 weight percent" that belong to the group of carbon-containing production percentages, preferably 20 to 40 percent by weight silicon carbide stones Although the highest SiC, or in addition to 40 to 65 percent by weight Al ₂ O ₃ thermal conductivity of all refractory building materials and 35 to 60 percent by weight SiO _{2 in} addition, these stones are used in foundries and smelters - 10 to 45 percent by weight, preferably 20 to industry do not play a role, since they contain 40 percent by weight SiC in the presence. 15 oxygen-rich furnace gases oxidize the stones and 2. SiC-based refractory brick would be destroyed according to inflation under inflation. Also in claim 1, characterized in that the runner heating cables of the coking ovens prevail, however, stones have a thickness of 50 to 65 mm. oxidizing atmosphere. It has therefore been shown that the known silicon carbide bricks, which in addition to 20 50 to 9ü% SiC essentially Al ₂ O ₃ and SiO ₂ contained, are unusable in coking ovens because they are sensitive to oxygen, so that in the Coking furnace to a regression of the SiC SiO ₂ and Z and thus the wall will soon fall apart. Coking ovens with a high throughput capacity are required from German patent 332 382 term for the coke to burn out at Heizzugtempera- finally known that the lining of Verturen from 1200 to 1400 ° C 16 to 20 hours. A coking furnace, which should be operated continuously, should consist of further increasing the throughput of the coking SiC-containing refractory bricks. Stoves are very desirable, but in many places, stones are supposed to serve as masonry, which leans against a high, because this increase has heat storage capacity according to the current state of the art. Furthermore, in each of the technology it should only be achieved by increasing the heating flue horizontal level of the furnace between the heating temperature. An increase in the storage and charging material a Temperaturunter-Heizzug Temperatur to z. B. over 1400 ° C conditionally different from about 300 ⁰ C prevail. Apart from that, however, a considerable complication of the operation 35 that with the lining according to the invention by the higher heat radiation. Since the known discontinuously operated coking ovens have a th brick lining made of fireclay and silica bricks, the temperature of this stress is only able to withstand a short period of time and the charging of the stoves. This means that the temperature achieved in this way is at most about 30 to 40 ° C. Even a high increase in throughput only with a heat storage capacity of the masonry would have to be bought for the increased furnace wear. discontinuously operated coking furnace from The invention is based on the consideration that a disadvantage. Increase achieved without other disadvantages The invention is based on the object for The throughput of coking ovens can only be achieved if, instead of the usual increase in throughput, a selection of stone materials such as fireclay and silica bricks, certain SiC-containing refractory bricks with a thermal conductivity of around 1200 ° C are made / have mh ° C, 1 to 1.5 kcal / mh ° C, a thermal conductivity from 2.5 to 6.5 kcal, for lining preferably 3 to 4 kcal / mh ^° C., having,
discontinuously operated coking ovens SiC-50 This object is achieved according to the invention in that refractory bricks containing increased thermal conductivity are used in that the bricks, in particular the runners, are used. Binder blocks, in addition to SiO ₂ , 10 to 45 weight The refractory bricks known in coke oven construction percent, preferably 20 to 40 percent by weight SiC, are the silica bricks, which consist of over 90% SiO ₂ or 40 to 65 percent by weight Al ₂ O ₃ , and the fireclay and sillimanite bricks, 55 to 35 60 percent by weight SiO _{2 in} addition to 10 to which essentially contain about 40 to 65% of Al ₂ O ₃ 45 percent by weight, preferably 20 to 40 percent by weight and the rest of 35 to 60% SiO ₂ and all percent SiC. Cases from oxides of trace elements, such as especially refractory stones, i.e. silica stones, shamolts special Fe ₂ O ₃ , MgO and CaO exist. From the stones and sillimanite stones sin <1 - insofar as they also contain about 10 to 45% SiC in the magazine "Technische Mitteilungen" 59 (1966), 60 - in the coke oven plant pp. 452 and 453, it is known that the through- in contrast to SiC bricks with a SiC content rate performance of a coking furnace in addition to the chamber of 50% and above, dimensionally accurate and wide and the heating cable temperature also has a better mechanical strength than the thermal conductivity of the Steinmalcrials is dependent on. Silica and fireclay bricks without SiC content, so one has only learned from this knowledge that for the runner bricks of the heating flues strengths, the density (porosity) of about 50 to 65 mm is sufficient. You can even - if mainly used silica stones by copper - this is statically justifiable - should increase even weaker iron or tilane oxide salts. be formed, for example a thickness of 40 mm,