万吨无回收焦化方案.doc

Proposal of 800,000tpa Clean-Type Heat-Recovery Coking Project 1. Background Our M/s Shanxi Provincial Chemical Design Institute, a first grade institute of coking plant design in China, possesses a great number of patent and proper technologies. Especially, she claims a highest level and richest experience in China in clean-type heat-recovery coke ovens development & research, design & engineering, construction & management, and initial heating up & trial- production. It is in the highest level both in China and overseas. Since 1980s M/s Shanxi Provincial Chemical Design Institute has studied clean type heat-recovery coke ovens, and then industrial production was began in late 1990s. In 2001 commercialized clean type heat-recovery coke oven technologies was put into large-scale mechanized and automated production. At the same time, the Institute compiled documentations such as Norms and Specification for Bricklaying and Construction of Clean-Type Heat-Recovery Coke Oven, Norms and Specifications for Installation of Clean Type Coke Oven, Specifications for Heating Up the Clean Type Coke Oven, and Systems for Management etc. In November 8, 2001, the inventor applied to concerned authorities for practical new-type patent and inventive patent. In September 4, 2002 the letters patent was authorized with Patent No. ZL01270184.X. In February 8, 2002 on the first patentee meeting, M/s Shanxi Provincial Chemical Design Institute was accredited as the sole institution in China to use, promote and develop the patent. In June 11, 2003 on the second patentee meeting, M/s Shanxi Provincial Chemical Design Institute was empowered to improve, standardize, and commercialize the implementation of the patent. M/s Beijing Sino-Steel Industry & Trade Group Corp is the sole promoter for Clean-type Heat-recovery Coke Oven outside China. In 1999, a pilot plant containing 18 ovens was put into production. Up to now there are five clean type heat-recovery coke oven plants that are operating normally, and fifteen plants that are under construction. The reference list is as follows: . Reference List of Our Achievements In Operation No.PlantCapacity Put-into- production Time 1Pilot Plant in Shanxi Houma18 ovens1999 2TaiYuan Gangyuan Coking Co.400,000tpaJuly, 2003 3Shanxi Fenyang Wenfeng Coking Co.500,000tpaJune, 2003 4Shanxi Gaoping Xingao Coking Co.400,000tpaAugust, 2003 5Shanxi Lvliang Fuli Coking Co.400,000tpaMarch, 2003 6Shanxi Zhongyang Yaolong Coal & Coking Co. 200,000tpaNovember, 2003 Under Construction PlantCapacity Estimated Commissioning Time 1Taiyuan Loufan Wanguang Coal & Coke Co. 300,000tpaMay, 2004 2Taiyuan Loufan Limin Coal & Coke Co.200,000tpaNovember, 2004 3Shanxi Lishi Liangyu Coking Co.200,000tpaFebruary, 2004 4Shanxi Lishi Shuangfu Coal & Coke Co.400,000tpaMay, 2004 5Shanxi Linxian Xinmin Coking Co.400,000tpaAugust, 2004 6Shanxi Fenyang Longquan Foundry Coke Co. 400,000tpaApril, 2004 7Shanxi Lanxian Fengda Coking & Metallurgy Co. 400,000tpaNovember, 2004 8Shanxi Qinxin Coal & Power Co.600,000tpaOctober, 2004 9Shanxi Qinshui Qinmao Coal & Coke Co.600,000tpaNovember, 2004 10Shanxi Luxin Coal Gas Co.600,000tpaNovember, 2004 11Shanxi Coking Coal Group Corp.800,000tpaOctober, 2004 12Hunan Loudi Xingxing Coking Co.300,000tpaJune, 2004 13Shandong Tsingdao Iron & Steel Co.600,000tpaMarch, 2004 14Jiangsu Zhuxi Iron & Steel Co.600,000tpaOctober, 2004 15Shandong Shunxin Coke Co.400,000tpaAugust, 2004 . 2. Profile of 800,000tpa Clean Type Heat-Recovery Coking Plant The proposal includes coal receiving from transfer house, coal handling, coal stocking, coal preparing, coking, screening, coke crushing, stocking, transferring to stock house and suitable utilities. Four grades of coal are used to prepare the coal blend. In the coal yard, forklift is used to transport coal into coal receiving pit, which is successively blended in blending bunker, and pulverized by counter hammering pulverizer. The coal is coked in clean-type heat-recovery mechanized coke ovens typed QRD-2000 with stamp-charging process. With silica bricks as the refractory of their main bodies, the coke ovens adopt high alumina bricks as part of the refractory of oven head, and fire clay bricks and ordinary red bricks as part of the refractory of oven bottom and oven roof. The plant consists of 128 ovens of 8 batteries, each containing 16 ovens, and self-adjusting suction devices. The coke is screened to 3 grades as per the customers requirements. Space is prearranged for a 2x12MW power plant utilizing the waste heat from the coke ovens. The whole design was featured by advancement in technology, security & reliability, economy & applicability, and cleanness in production. 3. QRD Clean-type Heat Recovery Mechanized Coke Oven with Stamp- charged Process QRD clean-type heat recovery mechanized coke ovens with stamp-charged process, with 8 batteries of 128 ovens, are arranged in two lines. Each line consists of 4 batteries with a rated capacity of 300,000tpa. The whole plant can be either put into production with a entire capacity i.e. 800,000tpa or start with half rated capacity i.e. 300,000tpa. 3.1Brief Description of Structure of Coke Oven QRD clean-type heat recovery mechanized coke oven is composed of carbonization chamber roof, bottom, main wall, side gate and iron components to protect the coke oven. 3.1.1Oven Roof The Roof is of arch type. To prevent coke from melting, adjustable . primary air inlets are evenly installed in the arch, which form a waste- gas-protecting layer between the coal and burning zone on the oven roof. 3.1.2Oven Bottom Four linked arches are used on the oven bottom. On the base of the arches, adjustable secondary air inlets are installed to make the air evenly distributed in the flue. The air combusts with waste gas for a second time and makes the oven bottom be heated evenly. The fire channels of the main wall and the oven bottom can communicate with each other. An air layer is provided between the foundation of the coke oven and oven bottom to prevent the base plate from being overheated. 3.1.3Main Wall of Carbonization Chamber Evenly provided with a variety of fire channels, the main wall is equipped with suction-adjusting facilities. The operation in the oven is under negative pressure. 3.1.4Oven Gate The gate is of two sections. The upper is fixed and the lower is movable. The two-section design is able to prevent soot leakage and reduce the operative weight of the oven gate. The main material of oven gate is cast iron. The circle of refractory lining is high alumina brick and the middle is castable. There is also some silicious aluminium fabric. 3.1.5Iron Components The coke oven is equipped with iron protective components including oven column, upper and lower horizontal tie-rod, vertical tie-rod, spring and protective plate. 3.1.6Machines for Coke Oven Stamp-charged machine, coal charging & coke pushing car, quenching car. . (1)Stamping machine The stamping machine is operated hydraulically, coal cake is stamped in two layers and duration of stamping time is 20 minutes. (2)Charging and pushing car Coal charging process is one of the key technologies of the QRD- 2000 clean type heat recovery mechanized coke oven with stamp- charged process. The coke oven is charged sidewise, each carbonization chamber is charged with 45t dry coal and the charging process can be finished in 2 minutes. Cantilever box type coal charging process is adopted. A lifting and door sidewise removing mechanism combined with coke pushing mechanism is provided on the car, making the same car have two functions at the same time. The car is mainly composed of coal box, coal rod, coal box driving mechanism, end baffle, coke pushing bar, coke pushing bar driving mechanism, oven door opening and close device, supporting wheel and pressing wheel, car frame and the car operating mechanism, etc. The driver cabin is provided with air conditioning and the control devices for coal charging and coke pushing. (3)Coke receiving and quenching car The coke receiving and quenching car is located at the coke side, functioning for oven door opening and closing as well as coke receiving and quenching. It is mainly composed of oven door opening and closing mechanism, horizontal coke receiving trough, traveling mechanism, car frame and operating room, etc. The oven doors open and close hydraulically, the traveling mechanism is provided with tandem resistance speed regulated control system and electromagnetic breaker and necessary interlock devices. The driver cabin is provided with air conditioning. The coke receiving trough is of steel structure, with opening at both ends and being lined with heat-resistant cast plate, and it can travel horizontally and tilt forward. 3.1.7Automation The heating temperature and the suction pressure for each hole of the oven are self-adjusting. DCS control is adopted. . 3.1.8Material of Oven Body According to different constructive conditions and products, such as metallurgical coke and foundry coke, various refractory bricks are adopted e.g. silica bricks, clay bricks, aluminous bricks. 3.2Technical Features 3.2.1Volume of this type of coke oven is large and working condition is clean, which represent the direction for the development of international coking technology. 3.2.2Environmental protective technologies are adopted in the coke oven structure and operation process, such as coke oven negative-pressure operation, horizontal coke receiving, etc. No fume or dust emission occur during the whole process of coal charging, coking and coke pushing. No wastewater with harmful ingredients is produced during the operation process, thus clean production and pollution free working environment are realized. 3.2.3Hydraulic stamping is introduced which possesses the advantages of low noise and less maintenance. This stamping method makes a level surface of coal cake and reduces the exterior combustion of coal. 3.2.4The waste heat is used for power generation, which realizes comprehensive utilization of resources. 3.2.5A large amount of weakly caking coal, up to 40% of anthracite, or 5060% of lean coal can be blended with the coking coal. Such method leads to rational utilization of coal resources and reduces the coking cost. 3.2.6The coke is big in size and strong in strength. 3.2.7The investment is low and construction period is short. According to present market situation, the investment, including power generation by waste heat, is about 40% of that for traditional coke oven of the same capacity, and the construction period is 11 months. 3.2.8Power consumption is low and production process is simple. The operation is simple and convenient. For example, during the production no power like steam and low temperature water is consumed. 3.2.9There are less production process control points, which facilitates the . realization of automatically control and adjustment through computer. 3.3Technical Specifications of Coke ovens The refractories used for this type of coke oven are mainly silica bricks. Headers are provided on two sides of the oven body over the oven column. These types are mainly used to produce metallurgical coke. Carbonization Chamber Height2834mm Carbonization Chamber Length13340mm Carbonization Chamber Width (avg.)3596mm Carbonization Chamber Central Distance4292mm Dry Coal Charged One Time45tons Density of Briquette into the Oven1.01.1t/m3 Operation Period6668hrs 4. Technological Process Description 4.1Coal Preparing Coal is transported to coking plant by Jetty belt conveyor and piled up on coal yard by different grades. The area of coal yard is approximate 40000m2. Four coal receiving pits are provided in the cleaned coal yard. After pushed into the coal receiving pits by bulldozers or loading machines, coal is fed onto the belt conveyor through coal charging machine, and then conveyed to the top-level belt conveyor of coal blending bunker. Afterwards the coal is unloaded by discharging machine to the appointed coal blending bunker awaiting blend. There are five coal blending bunkers with a whole capacity of 2300tons. The lining of the bunkers are made of plastic materials. Electric belt scales are provided under the bunkers to Coal blend is transported by selected coal belt conveyor into PFCK reversible counter hammering pulverizer and ground with 9092% reaching the qualified grain size of less than 3mm. The moisture of the coal blend should be at 10% or so. If the moisture is not reached, water should be added. The qualified coal blend is again fed by the selected coal belt conveyor into the coal tower and stored there for coking. A combination of electric interlock central control and local control is . adopted in this system. Electric elements are dustproof, dampproof and explosion-proof. A sampling instrument is located at the end of the belt conveyor ahead of the pulverizer to take samples of coal blend for analysis. There also located an electro-magnetic Fe remover against the impurity in the coal blend. Mechanical dust remover is also provided. 4.2Coal Blending Industrial Test Coal of different grades will be provided by Indian side. After working out four to five schemes of coal blending, our side will conduct industrial test, in one of the commercial coking plants designed by us. Upon analysis and comparison the results in coke quality, coal cost and reasonable utility of resources, we will provide detailed test report for coal blending and coking. 4.3Coking The eligible coal blend from the coal preparing workshop section is delivered to coal tower under which situated the stamping station. Hydraulic stamping method is used. One coal cake contains two layers, incurring about 20 minutes stamping time. When charging time comes, coal blend directly falls into the skipper through a hopper outlet, containing half weight of a coal cake. A fluid driven flashboard valve and hydraulic cylinder driven chute provided beneath the skipper evenly discharge the coal blend into the stamp charging box where the coal blend is stamp charged to coal cake sized 12750x3400x1000mm with bulk density of 1.01.1 m3. The coal capacity is 45 metric tons. Coal box holding well stamp charged coal cake is loaded into coal charging car and transported to the oven where the coke is ready. Coal pushing car pushes out the coke in the carbonization chamber and immediately closes the coke-side oven door. The coal cake together with the charging plate is pushed into the carbonization chamber and the baffle on the coal cake end is locked on the oven door. The pushing car draws the charging plate out and immediately closes the machine-side oven door. Owning to the heat cumulated in the fire channels of the sidewall and bottom of the oven, the coking coal is heated and raw gas is separated out. Adjustable suction valves on the oven roof and oven doors allow the introduction of primary air to combust with raw gas. The temperature of the space in oven roof is thus increased and coal cake is heated up through heat exchange and radiation. Due to the inadequacy of air through suction valves, the reductive gas in the roof space and the coal cake form a protecting layer. Incompletely combusted gas leaks into the . machine- and coke-side descendent fire channel via the outlets on the two sides of the oven wall, and then into oven bottom fire channels. The fire channels of coke-side is separately adjusted from those of machine-side to calefy the oven bottom evenly. Each oven bottom fire channel is divided into four sections. Secondary air is introduced into the sections to burn with the combustible gas and heat the base of coal cake through heat exchange with oven bottom bricks. Air is introduced on basis of sections to ensure longitudinally evenly heating of the oven bottom fire channels. Adjustable air inlets are provided at the corner of the outside wall of the fire channels. Thermocouple measuring the bottom temperature is provided to control the ingress of air and assure the carbonization chamber to be heated evenly. Temperature is around 11001200 in the space of oven roof, around 12501350 in the combustion chamber of oven bottom. The final temperature in the center of coke cake is 1050. Gas from oven bottom fire channels flows into the ascendant fire channels on the other side of the oven wall and then into the ascendant tube at the center of the oven roof. To maintain the suction of the carbonization chamber, two batteries of 16 ovens share a waste gas header. The waste gas is discharged through a stack shared by four groups of 16 ovens. The prearranged heat gas flows into the waste gas heat recovery boiler and then to power plant. 4.4Coke Quenching Coke is transported to quenching tower by quenching car and quenched by automatically-switch-on quenching pump. Then coke is tilted forward to the drying platform and transferred to screening shop by coke discharging machine and belt conveyor. 4.5Coke Screening After cooled the coke is put by coke placing machine onto the belt conveyor and conveyed to screening tower to be screened. There are three screening grades: 8030mm, 3010mm, 70% Nut coke size1030mm Breeze coke size82 M107 CSR68 CRI2225 In case coal quality changes, coke quality and quantity should be finalized based on mutual discussion. 12. Initial Heating-up LPG serves as fuel in initial heating-up. 13. Waste gas 13.1Composition SO28% N267% O254% H2O19.6% SO215002000mg/Nm3 (before desulfurization) 400500mg/Nm3 (after desulfurization) 13.2Volume:258000Nm3/h 13.3Temperature:850900 13.4 The composition and volume of the waste gas will alter with the quality of the input coal. 14. Chemical analysis Coal, coke and waste gas will be analyzed. The main parameters are as follows: Coal ash content, moisture, volatile matters, sulfur, caking index, thickness of . colloid layer, grain size, etc. Coke moisture, ash content, volatile matter, sulfur, mechanical strength, CSR, reactive activity, porosity,