Coke batteries: device, principle of operation, purpose. Coke production technology

Metallurgical production is simply unthinkable without the use of coke, which gives energy to melt iron-containing ore in a blast furnace shaft. However, the process of obtaining coke is laborious and time-consuming. To create it, special industrial units are built called "coke batteries". Their structure, purpose and characteristics will be discussed in this article.

Definition

Coke batteries - a whole metallurgical complex, whose main purpose is to produce in the required volume of coke for its subsequent transportation to blast-furnace shops. These production facilities may differ in their dimensions among themselves, but in any case their dimensions are quite impressive.

Design

The arrangement of coke batteries is as follows. The main elements of these furnaces are the so-called coking chambers. It is in them that the process of laying raw materials takes place. The coking chamber in the furnace is not one dozen. Also the most important elements of the battery can be considered and the heating gaps in which fuel combustion proceeds. The approximate linear dimensions of the coking chamber are as follows:

• The length is from 12 to 16 meters.
• The height is 4-5 meters.
• The width is 400-450 millimeters.

In general, the complex, thanks to which coke batteries have the ability to work continuously for a long period of time, includes the following components:

• Receiving bunker, which receives raw coal.
• Division of mixing and crushing of coal.
• Distribution tower.
• Loading trolley.
• Coking chamber.
• Coke ejector.
• Extinguishing car.
• Tower of fire.
• The platform to which the cooled finished product is unloaded.

The furnace itself for the production of coke in its general form has in its composition:

• Chambers for loading coal charge.
• Heating partition with a system of heating channels.
• The system of gas distribution and air supply.
• Regenerator for heating air and exhaust gas.
• Stop valves and mechanisms.

Classification

Coke batteries, depending on the mode of operation, are periodic and continuous. These batteries can be heated:

• Exclusively with a blast furnace gas.
• Only with coke oven gas.
• A mixture of blast furnace and coke oven gas.

The heating circuit of the battery may include:

• Flap channel, through which gases have the opportunity to fall between the piers.
• Steam channel for recirculation.

The heating gas for the battery is supplied to it in two versions:

• Side, when the coke oven gas goes along the cornuco (gas distribution channel), and air and blast furnace gas - along the bottom channels of the regenerator.
• Bottom on a special air distribution network.

A few words about the regenerator

This special heat exchanger allows the coolant to be contacted with clearly marked coke oven surfaces. It is important to note that a hot heat carrier carries out heating of the cold wall and nozzles, and after that they, in turn, transfer heat to the cold heat carrier.

There are other types of heat exchangers, which are called "recuperators." In them, cold and hot coolants conduct energy exchange among themselves through a wall specially constructed between them. At the same time, hot gases flow down first, and then the flap valves are triggered, so that a cold airflow begins to rise from the bottom upwards.

Methods of fuel economy in coke-chemical production

The coking process itself is quite energy-intensive, which is caused by the consumption of a very large amount of fuel. Therefore, to reduce the consumption of its consumption, the following methods are used:

• Use the technology of dry coke quenching. Thanks to it, the thermal energy of the product is expended on heating steam or water. In particular, from one ton of finished coke, about 1 GJ of heat is obtained in the form of steam.
• Modernization of regenerators used to maximize heat from combustion products. For example, it is possible to increase the heating area at the nozzle.
• Calculation of the optimum time interval between valve switching. It goes without saying that the more often they switch, in the long run it will enable to reduce the volume of regenerators and heat loss in them. However, it should be noted that too frequent operation of the valves will inevitably lead to their rapid failure and additional load on all adjacent nodes and parts.
• Batch heating and dry quenching are carried out simultaneously.

Technological process

Coke production is very difficult. Therefore, in order to understand how this works in real conditions, it is worthwhile to learn the technological cycle in as much detail as possible.

The shop for the production of coke always begins with a coal tower. It is in it comes raw materials. In the lower part of the tower there are special closures. Through them coal is transported to the receiving bunkers of the coal loading machine. In order to exclude the possibility of the coal sticking inside the tower, compressed air is supplied along its entire height, which is supplied by intermittent impulses and ensures that the batch of the charge is adhered to the tower. The tower must certainly be filled with at least two-thirds of its volume.

The filling machine is filled either by volume or by weight. The process of filling it is controlled by scales. Coal is fed into the furnace immediately after the finished coke is dispensed. At the same time, the feed of the charge occurs through the top. At the time of loading of the coke oven, the person responsible for this - the hatch one - turns on the furnace in the gas collector and activates the injection. The entire download process takes three to six minutes.

After that, the furnace is sealed in the most careful way, and the process of heating the charge begins. The technology of coke production in coke oven batteries includes the following temperature processes:

• At 100-110 ° C, coal is dried.
• Within 110 ° С - 200 ° С, hygroscopic and colloid-bound moisture, occluded gases are released.
• At 200 ° C - 300 ° C thermal preparation takes place, which is accompanied by the formation of gaseous products of thermal destruction and the splitting off of thermally unstable oxygen-containing groups.
• 300-500 ° C - the temperature range at which a plastic state occurs. Gas and vapor are intensively released, a liquid phase is formed.
• 550-800 ° C - medium temperature coking. Synthesis is intensified.
• 900-1100 ° С - coking high temperature.

Coke shipment from the furnace

Coke battery, the principle of operation of which is described in this article, requires special preparation before the delivery of finished products from it. Not less than twenty minutes before the start of the issuance of the stove is necessarily cut off from the gas collector and communicate it with the atmosphere by opening the riser cap.

After this, the doors of the furnace are removed and the coconut is pushed out of the chamber into the quench car with a special bar. In this case, if for some reason the planned release of coke is delayed by more than ten minutes, then the door should be set back in place. Premature opening of the riser covers is strictly forbidden, as this can cause a serious collapse of the lining inside the battery. In addition, the furnace doors must necessarily be cleaned of graphite and resin before and after the process of issuing finished products. Extinguishing coke in a special car is a mandatory procedure, because without this operation the ready-made coke can again ignite.

Calculation of coke oven batteries provides that the furnaces must have a working and repair period. During the working cycle, coke is dispensed, and during maintenance work, maintenance of all units and equipment, cleaning and so on is carried out.

Essence

At the initial stage of coking, coal is dried, all adsorbed gases are removed from it and decomposition starts. At the moment of transition of coal to a plastic state, sintering begins - a process that is decisive for the whole cycle of coking. In the third stage, char is tested for calcination and hardening. It is the viscous mass that pushes the resistance of the gases on their way to the gas collector, thereby creating a coking pressure, which in practice is compensated by the shrinkage of the already formed coke.

Conservation

"Why can not you stop coke batteries?" - it is this question that can often be heard from the lips of a person far from the subtleties and nuances of coke production. The thing is that these units are oriented to work under certain conditions (high temperature, abrasive wear, etc.) and in case of an unscheduled stop without proper preparation these furnaces can lose their inner masonry, which simply collapses. However, in practice, it is sometimes necessary to suspend the operation of a coke oven battery and perform specified conservation measures. How it works - to describe for too long, it is only necessary to indicate that there is a so-called "cool" and "hot" conservation. Which option to choose - it is decided directly by the head of the company, depending on the situation and the reasons for the suspension of the unit.