Refractories for coke oven doors

Conclusions The main requirements of refractories for the doors of coke ovens are enhanced strength and thermal-shock resistance, and a reduced thermal conductivity. The use of chamotte articles due to lamination leads to scaling and spalling, and increases the gas permeability of the structure and causes rapid wearing. The resistance of the brick is reduced with an increase in the volume of the coking chamber, and this equals 1.5–2 years.In recent years a start has been made with the use of block concrete linings for the doors of coking ovens on the basis of concrete containing chamotte fillers and aluminous cements. The resistance of concrete blocks reaches 4–5 years or more. With block linings there is a reduction in the number of joints, ensuring mechanization of the installation and demolition of the lining, and a reduction in the time spent on lining operations.Two types of Soviet designs are used for the doors of coke ovens with block linings. The most promising is the nonreinforced lining with removable components, permitting independent changing of the blocks, and repeated use.Abroad, research is going on into reinforcement of blocks with metal fibers of special composition and the use of fused quartz for preparing the blocks.Translated from Ogneupory, No. 8, pp. 38–43, August, 1984.     

Refractory lining of coke ovens

A new technological solution that makes it possible to reduce the duration of coking and increases the effi-ciency of coke ovens is described. The effect is provided by lining the walls of the coke oven with shaped dinas refractories with a blind hole in the form of a truncated cone. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 7, pp. 42, July, 2000.     

Dust-free coke discharge on the machine side of coke ovens

Operational experience with a system for dust-free coke discharge is outlined.     

Operation and preservation of coke ovens in the current economic crisis. 1. Stabilizing the available stock of coke ovens

Attention focuses on the condition of existing coke ovens and measures for their preservation and stabilization of their operation during times of economic crisis. Views on this topic from the Sixteenth Annual Seminar of Coke-Industry Specialists are reported.     

Optimal heating system organization in coke ovens

In optimizing the organization of the coke oven’s heating system, the feasible region of parameter values is identified and analyzed. Previous research has shown that optimal organization of the heating system calls for the forced recirculation of gas fluxes with recirculation rates exceeding those currently employed and also for measures that simultaneously permit energy conservation and curb nitrogen oxide emissions. To that end, the influence of recirculation on process parameters is analyzed in the present work, and the feasible region is found on the basis of the following constraints: no reduction of heat supplied for the coking process; and unchanged consumption of coke-oven gas. In addition, the basic parameters of the power generation subsystem are determined by assessing the energy balance.     

The use of alumina-carborundum refractories in coke ovens

Refractories and Industrial Ceramics -     

Contribution to the study of carbon deposition in coke ovens

The formation of carbon deposits from coal pyrolysis in a two-stage reactor has been studied for several cracking temperatures from 850 to 1000 °C. The weight of the carbon deposit was monitored continuously during pyrolysis by a thermogravimetric balance. Four successive periods of deposition can be distinguished:

1. (1) no weight uptake;

2. (2) a slow increase in weight;

3. (3) a sharp increase in weight;

4. (4) constant weight.

From the data, three distinct deposition rates have been calculated at different cracking temperatures: germination rate, growth rate and overall deposition rate. The general tendency is an increase in all three deposition rates with temperature. Scanning electron and polarized light micrographs of these deposits show that they have a laminar structure. There are two (sometimes three) cone layers, the first being formed during the liberation of water contained in the coal charge, indicating that water plays the role of an inhibitor in the formation of carbon deposits. The structure of the deposits is independent of the temperature at which deposition takes place. The mechanism of this carbon formation is discussed.     

Influence of heating-channel hearth on the combustion-product recirculation in coke ovens

The influence of controllable components in the heating channels on the uniformity of the temperature distribution over the coke-battery height is studied. Means of improving coke-battery heating are proposed.     

An investigation of different forms of refractories for the service conditions in coke ovens

Conclusions Investigations of different forms of refractories established that it is desirable to use refractory parts with high heat resistance (MK-80 mullite-corundum, silicon carbide, chamotte-cordierite) as extreme roof and hearth parts in place of chamotte ones for increasing the life and providing reliability in service of these elements of the coke oven lining. The most promising for these purposes from the economic point of view and taking into consideration high heat resistance, resistance to reduction, and minimum thermal expansion are chamotte-cordierite parts.Translated from Ogneupory, No. 2, pp. 36–37, February, 1991.     

Creep of a dinas based mortar used in coke ovens

Conclusions Owing to the competition of the growth process occuring due to the phase transformations of quartz, the compressive creep of the specimens of the MDK-1 dinas mortar is low and in the 1100–1300°C range, it amounts to 0.2–0.3% within a period of 50 h at a stress of 0.6 N/mm²; and it amounts to 2–2.5% at 1400°C under the same conditions. A stress level of 0.2 N/mm² is insufficient to suppress the growth of the mortar (in the original mortar specimens as well as in the specimens fired at the test temperature for a period of 10 h). The deformability of the constituent specimens having a mortar joint is determined mainly by the deformation of the mortar layer.The rigidity of the experimental dinas mortar indicates its low capacity to relax the stresses in the coke oven lining.Translated from Ogneupory, No. 6, pp. 1–5, June, 1989.