Needle coke is the main raw material for ultra high power electrode, superduty capacitor, lithi?鄄um ion electrode and so on. Its intensive technology refers generally to that the process equipment performance is improved by depending on scientific and technological progresses and maximum economic benefit is obtained by minimum material and energy consumptions. The needle coke, carbon fiber, solvent oil and refractory binder after refining of raw materials are taken as the major products lines for the intensive technology for the coal based needle coke. The needle coke, gasoline, diesel oil and superduty active car bon are taken as the major products lines for the intensive technology for the petroleum based needle coke.
Study on releasing regularity of nitrogen-containing compounds of gas phase during anthracite pyrolysis
The releasing regularity of HCN, NH3, N2O, NO and NO2 in the pyrolysis products of pulverized anthracite at 830℃, 880℃ and 930℃ are studied with a high temperature sedimentation furnace. The result shows that with the increasing of temperature, HCN, NO, NO2 and NOx are separated out from the nitrogen of coal specimen and the trend of conversion rate of nitrogen-containing compounds of gas phase is decreased first and then increased. The conversion rate of NH3 is increased first and then decreased; the conversion rate of predecessor of NOx is increased gradually; the conversion rate of N2O is decreased gradually. The predecessor of NOx is the main nitrogen containing product of gas phase of coal specimen pyrolysis.
The low cost purchasing system for coal blending consists of coal property recording management system and coal purchasing optimization system. The coal property recording management system can carry out the recording, modification, computation of property parameters of all coals for coke making, obtain the average values of coal property parameters within different time periods and provide coal property parameters for coal purchasing system. The coal purchasing optimization system can obtain the minimum price purchasing proposal for coal blending that can meet the coke quality requirement and net price under all restricting conditions automatically by utilizing SOLVER planning and solving method, under the restricting conditions such as coal and coke quality predictions, net price of coal (coal price-byproduct price）, coal purchasing etc. so as to realize the long term controls of the high quality, stable production and minimum production cost of coke from the purchasing link.
Mongolia is rich in coal reserves, coal price is low and the caking index is about 50. In order to use the coal from Mongolia and reduce the cost of coal blending, the coal is used to carry out test and study for stamp-charging cokemaking with 40kg test coke oven. The study shows that the coal has high reactivity and the coke produced by separate cokemaking has a high reactivity and low strength after reaction. Under the condition of the good basic coal, the coke with M40≥80%, M10≤7%, CRI≤30% and CSR≥60% can be made with about 20% of the coal from Mongolia.
The difference of coke cake shrinkage of the stamp-charging cokemaking and top charging cokemaking as well as the influence factors were analyzed. The problems of low volatile coal blend in stamp-charging cokemaking design and production were studied, and the following measures were put forward: heating level was properly reduced； the coking time was rationally set；the charging car which can adjust the width of coal cake was designed；according to Vdaf value and X value of coal blends, the coal cake width and height were adjusted, the production was guided with XD value so as to ensure that there was enough gap between coal cake and oven wall and suitable space temperature.
Thermo-mechanical analysis（TMA） can determine the transport ratio and rate of displacement of probe in the process of heating of coal ash continuously and can observe the melting point of coal ash in the whole process of heating. In comparison with the traditional ash melting point temperature tester（AFT） method, TMA can avoid the subjective influence of operator and improve the repetition rate and reproducibility of melting point determination.
The analysis of the distribution regularity of vertical flue temperature shows that the temperature of the vertical flue is determined together by the heating gas flow rate and the heat absorbed by the coking chambers on both sides. For the coke oven with 5-2 sequential operation, the lowest point of vertical flue temperature is at the time about 5h after the banking and the coke in the coking chamber on the other side is near mature. The highest point of the vertical flue temperature is at the time before and after coke pushing from coking chambers on both sides.
Study on the flue gas flow features in gooseneck and gas collecting main of coke oven with heat recovery
A mathematical model is established for the existing problems of the gooseneck and gas collecting main of a coke oven with heat recovery. The flow heat transfer in them is analyzed and studied by the utilization of the CFD numerical simulation software. The result shows that under the conditions of the fixed dimensions and good thermal insulation performance of the branch pipes of gas collecting main, it is as much as possible to increase the branch pipe diameters of the collecting main to balance the suction force of coking chambers to corresponding gooseneck and thus to increase the volumetric flow rate of flue gas from coking chamber at the end of branch pipe of the collecting main.
The collocation mode and control features of total CDQ mode elevator are described. The safety control of the position rotation coder, the safety control of synchronous traveling of the elevator and monitoring technology of elevator’s traveling space interval involved in the safety control technology of the elevator are analyzed. The corresponding solutions are put forward and can be used as the reference for the automatic control system for the similar process.
In combination with the installation of the CDQ water supply preheater of Baosteel, when preheater is installed newly, the designs of the key points, such as the selection of heat exchanger and the pressure regulation of circulation system are described in detail. The use of eccentric heat-pipe exchanger can solve the problems of the effective heat exchange of the system and wear of the system etc. Through the installation of water supply preheater, the circulating gas temperature at the inlet of CDQ chamber is lowered effectively, the coke treating capacity of CDQ chamber can be raised by over 5% and the ratio of air and coke is reduced by 50~100m3/t of coke.
The running condition of stamp-charging coke oven modified from 4.3m top-charging coke oven is respectively evaluated from the aspects of coal blending cost, production equipment, environmental protection and process, after modification the cost of coal blending is lowered by 50~180 RMB yuan/t coke, both production failure time and equipment failure time are respectively postponed by 10.7 time and 3.3 time, meanwhile K2, Kb and Kc are lowered to different extent, under the premise of ensuring that oven wall is not damaged, its index of coke strength after reaction is slightly lower than that of originally-designed stamp-charging coke oven.
By means of the measure of shortening the cycling time, controlling the size of coal blend, improving the charging operation and modification of the leveling bar, the coal charging amount is increased, the effective volume of oven chamber is fully utilized, so that coke production is steadily increased.
The algae and coal blended in different ratios are co-carbonized with coal under low temperature by low temperature carbonization process to study the change of coal tar. The result shows that in coal tar, the content of light oil is increased by 29.55%, the content of naphthalene genera compounds is increased by 9.15% and phenols compound content by 23.93%. Light-weight is realized in a certain degree.
Gas desulfurization liquor is treated with aluminum chloride coagulant. The effects of the factors, such as aluminum chloride concentration, agitating speed, pH value, sedimentation time etc. on the oil removal result are discussed. The influences of the factors on the removal results of turbidity and colourity are investigated. The experimental results show that the oil removal rate and turbidity removal rate can reach 56.82% and 75.26% respectively when aluminum chloride concentration is 800mg/L, agitating speed is 200r/min, sedimentation time is 3h and pH value is 8.0, but the colour removal capability is very low.
The conditions of scale formation of the waste water containing oil and ammonia in he stripping system and the principle of scale prevention and removing with quantum tube passage clearing ring are described. According to the features of the scale in the ammonia liquor stripping system, a quantum tube passage clearing ring is installed on the main pipeline for incoming ammonia liquor. Through 4-year continuous running, it is proved that the quantum tube passage clearing ring can remove the existing scale, prevent the formation of new scale effectively and ensure the stable operation of the ammonia liquor stripping system.
The coking waste water is disposed effectively with AOO process and discharged water indexes are up to the national grade II standard. The existing problems are analyzed, the corresponding improvement measures are taken and the incoming water flow rate is controlled strictly. AOO process is modified into OAOO process, the incoming water load for biochemical disposal is reduced and the system is operated smoothly.
The change of atmospheric pressure in tableland area is analyzed. With the increase of the height above sea level, the atmospheric pressure becomes lower and lower, the oxygen content in air becomes less and less, but the actual oxygen demand for treating coking waste water is not changed, therefore the increase of air supply is required. When blower is selected, the capacity of blower should be higher than that of the blower used in plain area.
The source and harm of coking waste water are described. The advantages and disadvantages of the ammonia stripping process with direct steam, ammonia stripping process with heat conducting oil and ammonia stripping process with pipe still are analyzed and the operation costs of two ammonia stripping processes are compared. Finally the suggestions are made for the selection of ammonia stripping process.
The varieties of coking waste water are classified through the analysis of the sources of coking waste water. The “Discharge Standard for Pollutants from Coking Industry” to be promulgated has much more strict discharge requirement for coking waste water and the regeneration and utilization of coking waste water are more necessary and urgent. Through the analysis of the water quality the diversified ways for the regeneration and utilization of coking waste water are put forward.
The cognizing process of the relation between coke reactivity and blast furnace ironmaking is summarized. The effect of the coke with different reactivities on the ironmaking process of blast furnace and present study situation of technological means of the production of the coke with different reactivities are expounded. Through the discussion on the adaptability of the coke with different reactivities to the blast furnace ironmaking condition, it is put forward that the suitable coke reactivity should be specified according to the blast furnace ironmaking condition and reducing property of iron ore.
The velocity field simulation of multi-tube rotary type coal moisture control process done by Fluent software. The velocity distribution of flue gas in the drier is studied and the regularity of the flue gas flow in the process of coal moisture control is obtained. A pilot test is carried out in the multi-tube rotary type coal moisture control system with a capacity of 1t/h. The test results show that under the conditions of flue gas consumption 2 000m3/t of coal powder, 245℃ of flue gas at the inlet of the system and coal moisture of 12%, the moisture of coal powder is reduced to 6.7% and requirement of coal moisture control is met.
Test for top-charge and stamp-charge coke oven batteries by 40kg test coke oven is described in this paper, which shows that the stamp-charge process can obviously improve the cold strength, crushing strength, abrasion strength and CSR of coke but it would uniformize the grain size composition since it has little effect on the CRI.
This essay discusses the influence of coking period to coke quality by changing the coking period of 5.5 stamped charging battery, provided that the coal blending ratio is constant. The result shows that by suitably extending coking period, coke anti-crush strength and coke strength after reaction can be efficiently improved, anti-wearing strength and reactivity of coke can be improved, sulfur content in coke can be reduced, and charging cost can be reduced by blending more poor coking coal.
By using the coking coal from Yunnan and Guizhou as basic coal, blended with 10%~15% Austrilian gas fat coal and 10% anthracite coal from Yunnan Zhaotong for stamp charging coking, gas production is increased, meanwhile the mechanical strength of coke is not influenced. In turn chemical product recovery ratio and methanol production are increased.
The infrared automatic temperature measuring system has been developed for the current characteristics of battery heating system. This system can measure the temperature of vertical flues exactly and make temporary adjustment to stop heating according to temperature trend. It will control heating wall temperature exactly and improve battery temperature uniform to reduce heat consumption of battery.
The coal cake of traditional stamping operation has been separated to seven layers and make strapezoid bulk density distribution of coal cake. The operation can be adjusted according to stamp work and coal filling quantity of each layer. The bulk density and stamp work of each layer are in descending order from the bottom to the top layer, and coal layers are overlapped. The stamp time of each oven become shorter to 420 seconds and 20% work capacity higher. Coal cake collapse rate is decreased from 10%~20% to 0 and charging coal moisture is decreased from 14% to 12%. The shear resistance strength and high thermal efficiency have been improved.
This paper introduces the defects of built-in type limit detector for electrical cylinder charging mechanism in CDQ system in real production, which has been replaced by a newly-innovated mechanism that shows a satisfactory performance.
A modification is done for the problems in graphite purging device, such as low availability, high failure rate, low graphite removal efficiency and graphite seriously deposited at coking chamber wall and charging hole frame, etc. due to the design and material used not matched to the actual working condition of the graphite purging device. This improvement can remarkably benefit graphite removal, pushing current reduction and hard pushing prevention.
By summerizing and analyzing the process control conditions of 6.25m stamp-charging battery such as coal belending structrue, quality of coal blended and heating schedule, this essay concludes suitable pushing current control conditions. In order to have stable operation. It is required to control the blended coal as per the follwing indexes, coking fat coal≤55%, fat coal≤10%, Vdaf≥28%, Rmax=1.11~1.17, b/a=15~30, G≤80, Y≤16.
By the compare of heat tube exchangers and water preheater work effect between the phase I and phase II CDQ of Jiu Steel, we elaborate the advantages and disadvantages of heat tube exchanger and water preheater of CDQ system.
This paper described a solution to various-degree damages to“Bracket”refractory at connecting duct of quenching chamber by utilizing β-SiC bricks instead of mullite-SiC bricks for service life extension of the quenching chamber refractory.
The principle, features and system composition of ABB industrialIT DCS control system are described in detail. The control function of DCS control system is utilized to carry out PID adjustment, cascade adjustment, ratio adjustment, adjustment in range etc., thus the accuracy control is realized and process requirement is met. The interlocking at various levels of production equipment is controlled strictly so as to avoid accident occurring. Through the rich alarm information, the analytical and decision-making basis is provided for trouble removal.
By taking p-xylene as the only carbon source and energy, one bacterial strain which has a high efficiency degradation capability to p-xylene is obtained by selection. The results of physiological and biochemical experiment and 16S rDNA gene identification indicate that the bacterial strain belongs to pseudomonas sp. Its optimum degradation conditions are pH=7.5, 30 ℃ cultivation temperature and mechanical shaker’s speed of 150r/min. The high efficiency bacterial strain is put into actual waste water and can degrade all p-xylene in it in a short time.
The production present situation of ammonia stripping system is introduced, against the problems existed in the existing process such as big fluctuation of column resistance, tar content and soda lye concentration as well as no way for automatic control of ammonia liquor deflegmator, by means of the measures of dismantling feed column plate, increase the height of outlet pipe of coal water tank, changing the soda adding mixer from the spiral type into the partition plate type, increasing soda standby pipe, realizing temperature automatic control, the good effect has been achieved.
By taking green vitriol（FeSO4·7H2O）as chemical agent, desulfurization test is conducted for the simulating sulfur containing waste water with sulfide content of 1 571.86mg/L and pH value of 9.5. The result shows that when the waste water has the initial pH value of 10, reaction temperature is 35℃ and the adding amount of green vitriol is 16g/L，the best desulfurization result can be obtained. The removal rate of the sulfide in the waste water is up to 99.69% and the sulfide content in the waste water at outlet is reduced to 4.83mg/L.
The heat tube technology and advantages of heat tube exchanger have been introduced and analyzed in the text. The heat tube air preheater has been checked to be used for low temperature emission heat recovery of tube furnace. The thermal work and benefit have been calculated. By the research conclusion, the heat tube technology can improve 10.21% heat capacity of heating furnace, save 5.08×106m3 COG and reduce 2.9×107m3 emission discharge per year and achieve marked effect of conserve energy and reduce emission.
This paper studies the source of chloride ion in ammonium sulfate crystallizing system and its effect, and also makes a proposal to control the content of chloride ion. Because the input and output of chloride ion is not balanced, chloride ion content in mother liquor is too high. As a result, the equipment will be corroded. Therefore, chloride ion content must be controlled for good product quality and system safety.
The technology for ammonia removal from coke oven gas is described and the process, for the production of concentrated ammonia liquor with ammonia scrubbing with ammonium phosphate and other gas ammonia removal processes are compared. The produced concentrated ammonia liquor is characterized by high purity, wide application and better economic benefit of the process. The domestic design of the process has been realized at present.
This paper discovered that the recovery rate of tar and light benzol from stamp- charge battery are both lower than that from top-charge battery by analyzing the reasons affecting recovery rate of by-products from the stamp-charge battery so that cokemaking process should be optimized during the stamp-charge battery production.
Ammonia recovery process is described in this paper, i.e. the ammonia vapor used to be burnt out in A.S. process will be recovered for emission desulfurization in sinter plant, with liquefied ammonia saved by 4 500t annually and with direct economic benefit up to 17.1 million RMB; the concentrated ammonia liquor is delivered to saturator for producing ammonia sulfate fertilizer, with production of 18 250t each year and with economic benefit up to 25.55 million RMB.
This paper described a solution to the problems of HPF desulfurization process, such as big fluctuation of desulfurization efficiency, low intensity of circulating spray in absorber, low ammonia sulfur ratio and high secondary salt in desulfurizer liquor, etc. so that remarkable desulfurization efficiency and increasing stable operation of the desulfurization system can be achieved by means of improving absorber spray intensity, adding salt abstraction device and reducing the temperature of desulfurization system, etc.
The existing 9 water seal pots are modified according to the actual situation, such as water seal blockage, big energy consumption, inconvenient management, etc., i.e. make-up water are not needful and the gas condensate is changed to closed-circuit recovery so that pollution can be alleviated.
ISSN 1001-3709 CN 21-1164/TQ Sponsor:ACRE Coking & Refractory Engineering Consulting Corporation,MCC Postal Code:8-28
