19965438+September 0 ~1July 995 is the first stage of the transformation of coal injection system in the first ironmaking plant of Jigang. Due to factors such as technology, equipment, installation, construction and personnel quality, coal injection equipment often stops, and production is very abnormal. Mainly manifested in the milling equipment, such as: hanging grinding of the screw machine of the powder collection system; The flange of the spiral blade is broken; Equipment defects such as ball mill liner, screw fracture and powder leakage of ball mill barrel in pulverizing system have affected pulverizing production.
Retrofitting and improving the equipment that often breaks down: (1) The connection and intercommunication of the main coal injection pipe are reformed, and the problem of intercommunication between 1# boiler and 2# boiler, 3# boiler and 4# boiler is solved; (2) The hanging connection mode of the screw conveyor in the pulverizing system is improved, and the flange connection of the screw shaft is changed into pin chain, which solves the phenomenon that the connecting flange is broken due to poor concentricity of the shaft after the screw hanging is worn, and greatly improves the operation rate of the key equipment screw machine; (3) The φ2m disc feeder in the raw coal yard is equipped with a fixed raw coal screen to filter out some impurities in the raw coal, thus reducing the blockage of disc impurities and correspondingly improving the hourly output of the ball mill; (4) The improvement of wear-resistant steel castings at the corner of the main coal injection pipeline has improved the service life of the coal injection pipeline, and the use effect is good without replacement, which has improved the coal injection operation rate; (5) The plug valve and coal conveying valve of the injection system are changed into pneumatic ball valves, which improves the sealing and flexibility of the valves; (6) Add a low-pressure alarm device to the gas transmission pipeline of the air compressor to prompt the injection operator to take emergency measures in time to avoid the blockage of the injection pipeline. The above transformation gradually improved the coal injection process equipment, brought the equipment efficiency into play, and improved the operation rate of coal injection equipment, with an annual benefit of about 1.5 million yuan.
Second-stage transformation process
1July 1995 to1February 1995, the second stage reconstruction and expansion of the coal injection system in the first ironmaking plant of Jigang was carried out in the form of semi-shutdown. Renovation and expansion contents: (1) A set of 14t/h ball mill pulverizing system and two sets of injection systems are added; (2) At the same time, in the blowing device, the bag dust collector of the original two sets of 10t/h ball milling system was changed from an annular pulse small bag to a diamond back-blowing big bag, and the filtration area was increased from 198m2 to 1256m2, from the original primary and secondary cyclone dust removal to the primary and secondary ceramic multi-tubes, and from the original secondary fan dust removal process to the primary stage. (3) The coal feeding device of the injection system is changed from a mixer to a vulcanizer; (4) changing the impeller feeder used by the original air lock of the dust removal system into a conical air lock; (5) The flue gas furnace has been expanded from 32 burners with a furnace capacity of 13.63m32 to 39 burners, and the furnace capacity of 40m(6) The compressed air supply mode has been changed from 3 air compressors with coal injection and 20m3/min air compressors with 1 air injection to 4 air compressors with supplementary coal injection in Jigang.
The third stage transformation process
1996 65438+ 10 ~1998 June is the third stage of the transformation of the coal injection system in the first ironmaking plant of Jigang. In order to alleviate the passive situation of coal injection production, gradually adapt to the need of continuous coal injection in blast furnace to produce a large amount of coal, and make the coal injection production enter a benign cycle, the following reforms were mainly carried out: (1) The improvement of fixing a row of wedges on the liner of the ball mill cylinder reduced the fracture and powder leakage of the cylinder bolts and improved the operation rate of ball mill machine-made powder; (Dg50 ball valve improves Dg 125 coal unloading valve, which improves the sealing performance and service life of coal unloading valve and reduces the material cost; (3) The pressure relief and powder collection system of the injection tank was reformed, which eliminated the phenomenon of pressure relief and overflow of pulverized coal and improved the working environment and surrounding environment; (4) The motor ammeter is added to the small screw of the bag filter, which strengthens the monitoring of the working state of the small screw; (5) The injection tank realizes the technologies of automatic dumping, automatic coal charging and automatic pressurization, which greatly reduces the working intensity of operators and improves the stability and uniformity of coal injection; (6) The large and small gears of the ball mill are lubricated by oil from the thin oil station, which reduces the wear and vibration of the large and small gears and improves the service life of the large and small gears; (7) The improvement of the pulse valve of the bag-type dust collector improves the back blowing efficiency of the bag-type dust collector, and correspondingly improves the operation rate of the bag-type dust collector; (8) The improvement of the structure of the back-blowing valve of the bag filter improves the sealing degree of the back-blowing valve, reduces the consumption of back-blowing, and enhances the back-blowing ability of the bag filter; (9) Negative pressure technology is adopted in the bearing box of the powder exhaust fan to reduce oil leakage at the shaft head of the bearing box; (10) The ball mill is started at low temperature, which avoids the formation of the main bearing bush and protects the bearing bush. (1 1) The improvement of the program of unloading and calendering before automatic coal loading in the injection tank solved the problem of environmental pollution caused by residual pressure coal loading in the injection tank; (12) The injection system adopts nitrogen pressurized vulcanization technology, which solves the contradiction that blast furnace coal injection is affected by insufficient compressed air, and also creates conditions for mixed injection of bituminous coal and anthracite in the future.
The fourth stage transformation process
1July, 998 ~ February, 65438 is the fourth phase of the transformation of coal injection system in the first ironmaking plant of Jigang. In order to meet the demand of pulverized coal supply in the first ironmaking plant of Jigang, it was decided to transform some process equipment of the pulverizing system. The renovation projects are: (1)? 400mm screw machine is transformed into FU350 chain machine; (2) Retrofitting the flap valve and discharge valve of the powder collection system by pneumatic remote control; (3) transforming the fixed pulverized coal screen into a composite vibrating screen; (4) Installation of chain motion signal of chain machine; (5) Installation of chain motor ammeter; (6) Installation of 0 # injection tank group (No.1 Ironmaking Plant of Jigang); (7) Connection transformation of 0 # injection pipeline and pulverizing system.
Through the transformation of the above projects, the reliability and operation rate of the pulverizing system are improved, the accuracy and reliability of pulverized coal distribution are improved, the working environment is improved, the impurities in pulverized coal are reduced, the blockage of the distributor in front of the furnace is alleviated, and a good material foundation is laid for the stable operation of pulverized coal injection production. After several years of continuous innovation and transformation, the reliability and operation rate of the process equipment of the coal injection system have been improved. By the end of 1998, the passive production was changed to active production, which met the needs of coal injection in six blast furnaces, and the production of coal injection system made a qualitative leap, as shown in the table.
Annual coal injection quantity, coal ratio and cost index of the first ironmaking plant of Jigang
Year 199 1 year19921994199519961997/kloc-.
Annual coal injection: t27983772477810954316846182702214250.
Average coal ratio, kg 3314942326890104.
Cost (1), yuan/ton 82.4438+0.76. 58637.88888886866
Note: This cost index indicates the unit cost of injecting 1t pulverized coal, except the personnel and raw coal outsourcing cost.
Due to the technical innovation of injection process equipment, the benefits of reducing the unit cost of coal injection are as follows: compared with 1998 and 1997, the benefits are 6 177300 yuan; Compared with 1998, 1999 realized a profit of14.74 million yuan.
Through the technical transformation and innovation of process equipment, the No.1 Ironmaking Plant of Jigang not only improved the production index and process index, but also greatly improved the working environment of coal injection workshop, and passed the acceptance of clean workshop, which was highly praised by peers in metallurgical enterprises of other units. (1) The injection system is equipped with a first-stage vulcanizing device, which improves the dense-phase conveying capacity, reduces the consumption of compressed air and reduces the injection cost.
(2) The injection system is controlled by microcomputer, instead of manual adjustment of supplementary flow according to the change of gas source pressure, so as to stabilize coal transportation.
(3) The coal pulverizing system uses the return air technology to realize the semi-closed circulation of waste gas with certain heat and low oxygen concentration into the coal pulverizing system, and explore the mixed injection technology of bituminous coal and anthracite, so as to increase the output of the coal pulverizing table, reduce the gas consumption, improve the coal injection substitution rate and reduce the coal pulverizing cost.
(4) The coal pulverizing system further explores the automatic control of coal quantity under the automatic adjustment of the negative pressure of coal pulverizing, so as to maximize the output of coal pulverizing per hour.
(5) The flue gas heating furnace can realize automatic optimized combustion according to the top temperature, furnace temperature and air supply temperature, and make the most reasonable and economical use of gas resources.
(6) The ball mill adopts a new type of wear-resistant and deformation-resistant liner, which reduces the phenomenon of bolt fracture and liner falling off of the ball mill cylinder, further improves the operation rate of the ball mill and reduces powder leakage.
(7) A new pulverized coal distributor with reasonable structure and wear resistance is adopted in front of the furnace to reduce the rate of stopping spraying.
(8) The raw coal supply system realizes vibration screening, preheating and pneumatic control of the raw coal unloader, which improves the quality of raw coal, increases the hourly output of the ball mill and saves power consumption.
(9) Adopt high-efficiency coarse powder separator to improve the recovery rate of qualified pulverized coal.