How to play with large coke ovens

How to "play" with large coke ovens

in recent years, with the gradual large-scale equipment, large-scale coke ovens have become the general trend of coking technology development in the coking industry. The reason is that they have irreplaceable advantages in coke quality, energy consumption and environmental protection, but their structure is complex and technical management is difficult. The industry once regarded them as "hot potatoes". How can we "play around" the production technology management of large volume coke oven? This issue of "hot spots" shares the experience of some advanced enterprises in operating large-scale coke ovens for the reference of insiders

the definition of large coke oven changes with the progress of coking technology and the increase of coke oven carbonization chamber volume. According to the conditions for access to the coking industry revised in 2014, the minimum threshold for access to the top charging coke oven is that the carbonization chamber is 6m high and the carbonization chamber of the tamping coke oven is 5.5m high. The low-temperature constant temperature bath should be cleaned frequently. Therefore, insiders generally believe that the 7M and 7.63m top charging coke ovens with a carbonization chamber height of more than 6m and the tamping coke oven with a height of more than 5.5m are defined as large-scale coke ovens. By the end of 2016, there were 66 7m top charging coke ovens, 15 7.63m top charging coke ovens and 10 6.25m stamp charging coke ovens in operation in China. The total output of coke accounted for 14% of the total output of coke in 2016

large coke oven is the most complex thermal furnace with furnace structure. There are many factors affecting furnace temperature management, and multi-stage combustion process makes thermal parameters change rapidly. The stability of the furnace condition, the fine adjustment of thermal parameters and a reliable and complete control system are the key factors for the stable production and long life of large coke ovens

the condition of coke oven should be stable

the condition of modern large-scale coke oven is very sensitive to the change of coal index, the fluctuation of thermal system, the change of coking time and the influence of atmospheric factors, so we must ensure the stability of these external conditions

the coking plant of Shagang is to stabilize the furnace condition in this way: operate in strict accordance with the coking curve, do not unreasonably shorten or extend the coking time, reasonably arrange the furnace plan, reduce the abnormal maintenance time, and standardize the thermal management. In view of the problem of high moisture in coking coal, a lot of research is still needed. Shagang has invested heavily in building 64 coal storage silos and improving the automatic coal blending process of electronic scales. The accuracy of coal blending has been significantly improved, so that the quality of coke has been improved. In recent three years, the crushing strength of coke has been increased from 88.0% to 89.2%

Masteel coal coking company applies statistical technology to implement process control on the 7.63m coke oven. Evaluation and monitoring are carried out at all stages of the process, and the main operating parameters of the coke oven are checked and scored, so as to accurately judge the operating conditions of the coke oven, effectively monitor the working conditions of the coke oven at multiple levels and in all aspects, and strengthen standardized operation, cooperate with the coal fineness control at 73.5% ± 0.5%, so as to ensure the smooth and stable production of the coke oven and the stability of coke quality

Shougang Jingtang Xishan coking company carried out single factor coking time variance analysis to improve the cold and hot properties of coke with the best coking time. The crushing strength of coke has been above 90% for 3 years, the wear strength index is below 6.0%, and the thermal strength of coke is in a good state (see Table 1)

Shoushan coking company of Pingmei Shenma Group used the operation practice of 6.25m tamping coke oven for reference to break through the two bottlenecks of coal cake density and coal loading smoke control: develop high-efficiency elastic wheels and friction plates, adopt tamping hammers with fixed small spacing and low noise, anti-wear guiding technology, increase the coal cake density to 1.1 tons/cubic meter, and make the height width ratio of coal cake reach 13.5; A reliable sealing frame is set on the coal loading car, and with the help of the negative pressure generated by the proven system (pressure regulation system) of the riser of the adjacent carbonization chamber, the flue gas is introduced into the adjacent carbonization chamber. The 7.63m top charging coke oven is successfully transformed into a tamping coke oven, which was put into operation in October 2013. It is the first super large tamping coke oven in the world, realizing the diversification of coal sources and reducing the coking cost

thermal index should be adjusted carefully

thermal management of coke oven is a science. Coke oven pressure system and temperature system complement each other. The parameters of pressure and temperature must be measured and adjusted frequently, and analyzed and adjusted in real time to ensure the uniformity of temperature system with the stability of pressure system

taking the 7.63m coke oven as an example, due to the low heating level, three-stage air heating and the effect of the pressure regulation system of a single carbonization chamber, the machining of the piston rod that causes the temperature of the furnace top space to be greater than 850 belongs to ultra precision machining. The coke is too hot, the vertical brick gas channel leaks, and the yield of chemical products is low

in the thermal regulation of WISCO coking company, part of the second and third air ports were closed to make the air enter completely from the bottom, reduce the flame combustion height, stabilize the moisture and volatile matter of the coal, and appropriately expand the size of the spray plate; More than 20 leaking brick gas passages were grouted and sealed, and the semi dry gunning technology was gunned. These technical measures make the straight temperature uniformity coefficient KB reach 0.88

Shougang Jingtang Xishan coking company, in terms of the horizontal heating temperature regulation of the coke oven, assisted by the "fire fall" intelligent expert control system, the car body strength exceeds 50% of the EU standard, automatically determines the "fire fall" temperature of the coke oven, avoids the sharp fluctuation of production quality, improves the daily production organization arrangement and management efficiency of the coke oven, and reduces the coking energy consumption by 2.91%

the control system should be intelligent

the interlocking between mobile locomotives of large coke ovens is strong, and there are many factors related to thermal procedures. The operation time of a single equipment is delayed by a few seconds, which will also lead to the equipment of the next process being locked. Therefore, the intelligent operation of locomotives is the key

the key medium of proven system is that the circulating ammonia must be kept clean. In addition to strengthening the cleaning of bridge pipes, TISCO coking also added a filter for circulating ammonia to ensure that the bottom of the carbonization chamber always maintains a micro positive pressure during the coking process

the safety technical measures of large-scale coke ovens are of great importance. TISCO has re optimized these essential safety technologies, such as automatic nitrogen filling for gas shortage of coke oven heating equipment, automatic gas overpressure release, basement grating detection, CO detection, as well as the confirmation of four car network signals and automatic speed regulation of coke ovens. Its reliability has been fully tested in production practice, and the metallurgical coke rate has been increased from 89.80% to 90.40% in the past three years

the pressure and temperature measurement and regulation means of large-scale coke ovens have completely subverted the traditional management methods of 4.3m and 6m Coke Ovens. We must sum up experience in management practice and walk out of misunderstandings in improvement in order to give full play to the comprehensive advantages of large-volume coke ovens