100 TPD ROTARY KILN
Technical specifications:Capacity : 100TPD Technology : Coal based Process (SL/RN) Heat process time : 6-8Hrs (Continuous) Power consumption : 75KW Power factor : 90 Frequency : Key parameters:After burning chamber : Rotary kiln : Length: 42000mm, Dia: 3050mm, Effective dia: 2450mm Rotary Cooler : length: 22000mm, Dia: 2400mm. 1. Lining procedure for rotary kiln, ABC, Stack and DSC. 2. Kiln light-up a. Diesel firing system 3. Main &auxiliary drive 4. Air injection system 5. Lubrication system 6. Hydraulic and pneumatic controls. a. Hydro thruster. b. Transfer chute cylinder. c. Stack cap cylinder. d. Kiln inlet and outlet slip seal. 7. Coal injection system. 8. Gas conditioning system. a. Feed water pumps. b. Water spray system. c. Flow control unit. 9. Fumes Extraction system a. ID fan. 10. Raw material feeding system. a. iron ore • Vibro feeders. • Double roll crusher. • Double deck vibrating screen. • Belt conveyors. 11. Product cooling system.
a. Cooler • 12. Product handling. 13. Ash handling system. 14. Hydraulic system. 15. Pneumatic system.
Materials required:•
• •
Cast able: - LC60, LC80, Insulation bricks and fire bricks, calcium silicate blocks, ceramic fiber, rock wool and Anchor bolts. Consumables: - Iron ore/Pellets, Coal, Dolomite. Auxiliary: - Air, water, hydraulic system and Electricity.
Working instruction Scope: a. Storage of different refractory materials: Castable and air setting mortar: store castable under dry, covered shed, on pallets, stack 10 bags high max. Insulation bricks and fire bricks, calcium silicate blocks, ceramic fiber, rock wool: store under covered shed, on pallets.
New furnace, new lining. I. II. III. IV. V.
Typical list of tools and tackles. Castable mixing, curing, lining inspection and repair procedure. Lining procedure for rotary kiln. Lining procedure for ABC, stack and DSC. Dry out.
Typical list of tools and tackles. 1. Paddle mixture 2. Needle vibrator 40/60 3. MS shuttering as per kiln diameter 0.75x1.2M/ply for cone area. 4. Storage drum. 5. Castable storage trays. 6. Buckets. 7. Measuring tapes. 8. Sample mould 160x40x40mm. 9. Thermometer. 10. Mallet. 11. Masonry tools.
12. 13. 14. 15. 16. 17. 18. 19.
Measuring jar. Plumb bob. Marker and chalk. Carpentry tools Spirit level Scaffolding pipes. Wire brush. Straight edge.
Castable mixing, curing, lining inspection and repair procedure. Clean all tools and tackles which shall be used for mixing of castable like paddle mixture, trowel, needle vibrator, buckets etc.. Empty the content of the bag into the mixture. Predetermined amount of fresh, cool and clean drinking water with manufacturer’s specified range at 15-20O C should be used for wet mixing. Ice shall be used to maintain the temp. Chloride content of water used for mixing shall be within 200-ppm max. Dry mix for about 2 min. then add the half the qty. of water as recommended by the manufacturer after mixing for about 1-2 min. add balance water. Again mix for 2-3 min. and discharge the material on wooden try. Ball in hand test shall be done before discharging the mixture to ensure proper water addition. This mix ready for casting. Ensure this mix used for casting within 30min. After casting the mix leave undistributed for min. of 8hrs. Ensure to cover the cast surface to avoid loss of water. Cover the surface with gunny bags moistened with water. Water shall also be sprinkled on casting plates to keep castable cool. Shutter can be removed after 24hrs. Of casting. Cure the cast surface min. of 48hrs. By sprinkling water/covering with moistened gunny bags. Inspect the cast surface for fallowing after curing 1. Surface cracks a. Hair line cracks. 2. Unevenness of surface. 3. Blow holes. 4. Soundness of lining.
Repair procedure 1. Hairline cracks may be ignored if only on surface. However if crack is wider it needs to be repaired. 2. To repair this crack castable, remove the castable exposing anchors and edges of the exposed castable area should be made like dovetail.
Lining procedure for rotary kiln. a. The shell on which lining is to be done shall be cleaned mutually by wire brushing to remove loose mill scale, dust, rust etc… b. The position of V anchors shall be marked as 150x150 and welded. Tip of the anchor shall be covered with plastic cap or insulation tape. c. Man hole/door thermo well etc... Should be wrapped with ceramic fiber/cardboard. d. Shuttering size will be 0.75x1.2M (kiln dia 3.0 M divided into 12 segment. 12th segment shall be key segment. e. Fix shuttering in alternate segment length wise in 7 O clock position, pour castable and consolidate using needle vibrator to achieve desired compaction. f. Rotation of the kiln shall be done after ensuring setting of last casted segment i.e. after about 4-6hrs of last segment casting. Precautions a. It should ensure that all openings means for doors instruments shall be protected by card board/ceramic fiber. b. Ensure proper flow of castable. c. Ensure adequate setting of castable before kiln rotation. d. Provision of PVC tape or paint at anchor tip.
Lining procedure for ABC, stack, DSC and kiln out let hood. a. The shell plate should be cleaned by wire brush to remove mill scale, dust, rust etc.. b. Marked and welded as 300x300mm space. c. Protect threading of anchor by cello/insulation tape. d. Backup layer of insulation castable/calcium silicate block to be installed first. e. Cut/pierce calcium silicate block as required according to anchor pitch. f. While in case of insulation castable gunning shall be done to required thickness. g. Dense layer shall be gunnited on backup insulation layer and thickness shall be maintained. Precautions
a. It shall be ensures that all openings meant for doors instruments shall be protected. b. Ensure adequate setting of castable. c. Provision of PVC tape or paint at anchor tip. Responsibility: Shift in-charge, refractory supervisor, mason. Hazards: dust, sound, heavy skull, bricks. Safety and PPE: safety shoes, helmet, hand gloves, nose mask, safety goggles, ear plugs.
Dry out and Kiln light-up 1. Dry out shall be done in accordance with recommendations as given below. 2. Steam shall not be used for the purpose of dry out. a. Cure at ambient temperature 2 days min. b. Slow wood log firing for 7 days. c. Raise the temperature to 125O C@20OC/hrs. Hold at 125OC for min. 24hrs. d. Raise the temperature to 300O C@15OC/hrs. Hold at 225OC for min. 24hrs. e. Raise the temperature to 600O C@15OC/hrs. Hold at 600OC for min. 24hrs. f. 600O C to process temperature at 50OC. g. If further process is not continued cool from 600O C to 150 @ 3035OC/hrs. h. Below 150OC cool for min. 24hrs. i. Naturally with sealing of all openings.
Housekeeping & environment:
Discard unwanted materials from platform. Keep in order required bricks and ramming mass. Keep clean and maintain working area. Fallow 5S housekeeping system all time.
5S Housekeeping 1 SEIRI : Sort out unnecessary items in the work place and discard them 2 SEITON: Arrange necessary items in good order so that they can be early picked up for use. A place for everything and everything in its place. 3 SEISO: Clean your work place thoroughly so that there is no dust on floors, machines and equipment.
4 SEIKETSU: Maintain High standards of housekeeping at work place at all times. 5 SHITSUKE: Train people to follow good housekeeping disciplines. Emergency or casualty: - If any emergency call Safety or Ambulance. HSD/LDO Pumps: Purpose: diesel firing for kiln Location: KCTB. Diesel pumps specifications: Name : HSD oil pump set Type : duplex No. of pumps : 2nos Type of pump : geared Capacity of pump : 350lph Delivery pressure : 28kg/cm2 Motor rating : 2hp/1440rpm Filter type :Y Filter location : 2at suction line, 3 at delivery line Other accessories consists of following Pressure gauge, isolated valve, Y-strainer, motorized pump
Working instructions
When kiln light up is over: 1. 2.
Responsibility: shift in charge (operation), shift in charge electrical Hazards: Safety &PPE: Housekeeping and environment:
Kiln Main and auxiliary drive Power Rated power Input rpm Nominal ratio Actual ratio Output rpm of G/B Torque at motor shaft Torque at G/B. output shaft Power Rated power Input rpm Nominal ratio Actual ratio Output rpm of G/B Torque at motor shaft Torque at G/B. output shaft
: : : : :
: : : : :
: 75kw : 166kw 1000 180:1 173.906:1 : 1000/173.906=5.75rpm 716.25n-m 117086.56n-m : 3.7kw : 19.5kw 1500 20:1 20.571:1 : 1500/20.571=72.92rpm 23.56n-m 455.51n-m
Cooler main and auxiliary drive Power Rated power Input rpm Nominal ratio Actual ratio Output rpm of G/B Torque at motor shaft Torque at G/B. output shaft Power Rated power Input rpm Nominal ratio Actual ratio Output rpm of G/B Torque at motor shaft
: : : : :
: : : :
: 22kw : 29.9kw 1000 112:1 108.849:1 : 1000/108.849=9.2rpm 210.1n-m 21497.02n-m : 3.7kw : 14.1kw 1500 20:1 20.249:1 : 1500/20.249=73.9rpm 23.56n-m
Torque at G/B. output shaft
: 449.44n-m
Start-Up Some manufacturers ship new gear-drive units with internal parts protected by a polar-type rust preventive film. There is no necessity to flush out this film, since it is usually soluble in the lubricant. (Consult the supplier of your particular gear-drive units for confirmation of this fact.) Merely fill the case with the recommended lubricant to the proper oil level. Always check to see if gear-drive units are shipped with or without oil from the factory. Units having bearings requiring grease must be checked and greased as required. When units furnished with forced-feed lubrication are first put into service, they should be checked to observe that oil is being pumped. When a pressure gauge is furnished with the unit, gauge pressure should be as specified by the manufacturer, or if not specified, the pressure should be approximately 15 to 30 psi with the sump oil temperature at approximately 160_F (71_C). Adjust the relief valve if necessary to obtain the pressure specified in manufacturer’s service manual. Each unit is usually given a short run-in at the factory as part of the inspection procedure. However, for complete run-in under operating conditions, it is recommended that the unit be operated at partial load for 1 or 2 days to allow final wearing in of the gears. After this period, the load should be gradually increased to rated value. After the unit has been operated under rated load for 2 weeks, it should be shut down in order to drain the oil and flush the housing. If desired, the original oil may be filtered, tested, and replaced. Filters finer than 25 micro inches may filter out the additives. After the original oil has been drained, fill the case to the indicated level with SAE 10 straight-run mineral flushing oil containing no additives. The unit should be started, brought up to speed, and shut down immediately as a flushing procedure. Drain off flushing oil, and fill with recommended lubricant to the proper level. After this initial oil change, an oil change is recommended after every 2500-hour or 6-month period of normal operation, whichever occurs first, unless there are unusually high temperature conditions combined with intermittent high loads where the temperature of the gear case rises rapidly and then cools off quickly. This condition may cause sweating on the inside walls of the unit, thus contaminating the oil and forming sludge. Under these conditions, or if the oil temperature is continuously above 150_F (65.5_C), or if the unit is subjected to an unusually moist atmosphere, oil changes may be necessary at 1- or 2-month intervals, as determined by field inspection of the oil. Synthetic oils, particularly hydrocarbons, may be used to improve oil life. Consult the manufacturer for recommended actions.
Lubrication Lubricating oils for use with enclosed gears and gear units should be highgrade, high-quality, well refined, straight mineral petroleum oils, within the recommended viscosity. They must not be corrosive to gears or ball or roller bearings. They must be neutral in reaction. They should have good
deforming properties. No grit or abrasives should be present. For high operating temperatures, good resistance to oxidation is needed. For low temperatures, oil having a low pour point to meet the lowest temperature expected is needed. When the operating temperature varies over a wide range, oil having a high viscosity index is desirable
Working instructions: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Good Maintenance Practice During normal periods of operation, gear-drive units should be given daily routine inspection, consisting of visual inspection and observation for oil leaks or unusual noises. If oil leaks are evident, the unit should be shut down, the cause of the leakage corrected, and the oil level checked. If any unusual noises occur, the unit should be shut down until the cause of the noise has been determined and corrected. Check all oil levels at least once a week. The operating temperature of the gear-drive unit is the temperature of the oil inside the case. Under normal conditions, the maximum operating temperature should not exceed 180_F (82_C). Generally, pressure-lubricated units are equipped with a filter which should be cleaned periodically.
Shutdown If it becomes necessary to shut down the unit for a period longer than 1 week, the unit should be run at least 10 min each week while it is idle. This short operation will keep the gears and bearings coated with oil and help prevent rusting due to condensation of moisture resulting from temperature changes.
Troubleshooting Gears Someone has observed that “gears wear out until they wear in . . . and then they never wear out.” This phenomenon more precisely as follows: It is the usual experience with a set of gears in a gear unit . . . assuming proper design, manufacture, application, installation, and operation . . . that
there will be an initial “running-in” period during which, if the gears are properly lubricated and not overloaded, the combined action of rolling and sliding of the teeth may smooth out the manufactured surface and give the working surface a high polish. Under continued proper conditions of operation, the gear teeth will then show little or no sign of wear. Despite the truth of this statement, failure of metallic gear teeth may occur as a result of excessive deterioration of the working surfaces of the teeth or as actual tooth breakage. In many such situations, early recognition of possible trouble may suggest a remedy before extensive damage occurs.
Responsibility: shift in charge mechanical and operation, shift in charge electrical
Hazards: Safety &PPE: Housekeeping and environment:
1. A flow diagram of a direct reduction plant for the production of DRI, of the type utilizing a rotary kiln, in to which a solid carbonaceous material acting as both fuel and reductant is fed at both the charge feed end and the discharge end. 2. The plant comprises an array of feed bins respectively including a bin-1 for supplying a source of iron oxides, such as ore, typically in the form of iron oxide pellets/natural lump ore; 3. A bin-2 providing de-sulfurising agent such as lime stone/dolomite for sulfur control;
4. A bin-3&4 (feed coal of 8-20mm), bin-5 (coarse coal 5-8mm) and bin-6
(fines 0-5mm) for providing a suitable carbonaceous reducing agent, typically in the form of coal of less than 20mm nominal diameter particles. 5. The iron ore, coal and dolomite are accurately proportioned and fed continuously as a charge to the feed end through feed chute of the rotary kiln. 6. A remaining bin-6 supplies coal, typically of less than 5mm particles injected to the discharge end of rotary kiln. Where carefully controlled quantities are injected or blown it. The coal is fed to a coal throw pipe from which it’s blown by means of low pressure carrier air form a lobe compressor. Through a coal injection pipe which we can adjust to achieve the optimum trajectory for this coal (up to 1/3 portion from kiln end side). 7. The reduction kiln may be typically 3050mm in outside shall diameter and 42000mm long, sloped at 2.5%. It may be supported on two tires and driven by 100hp variable speed DC motor and lined with 210mm of castable refractory. 8. In addition to the introduction of carrier air through pipe and kiln is equipped with a series of shell mounted air injection tubes, which are spaced along its length and extended to the interior of the kiln for drawing air from the outside and injecting it along the kiln axis to enhance combustion. 9. Each of the tube is equipped with its own fan and motor combination, so that the rate of injection may be properly regulated at spaced positions along the kiln. 10. Also, spaced along the kiln are twelve thermocouples; which are measure the average temperature of the charge in the kiln and of the gas. 11. The hot waste gas or off gases exhaust from the feed end to ABC, GCT, ESP and chimney. 12. The material discharged from the discharged end of reduction kiln by means of a sealed transfer chute consist of a mixture of DRI, coal char, coal ash, residual de sulfurising agent and other fine non magnetic particles. 13. This material is cooled in a rotary cooler, which is sealed from the ambient atmosphere, fitted with lifters, and cooled with externally with water. 14. The cooled mixture is then passed from the cooler to a screening system and screened.
15.
The two oversize particles
Chemical properties of coal Coal comes in four main types or ranks: lignite or brown coal, bituminous coal or black coal, anthracite and graphite. Each type of coal has a certain set of physical parameters which are mostly controlled by moisture, volatile content (in terms of aliphatic or aromatic hydrocarbons) and carbon content. Moisture Moisture is an important property of coal, as all coals are mined wet. Groundwater and other extraneous moisture is known as adventitious moisture and is readily evaporated. Moisture held within the coal itself is known as inherent moisture and is analyzed. Moisture may occur in four possible forms within coal: • • • •
Surface moisture: water held on the surface of coal particles or macerals Hydroscopic moisture: water held by capillary action within the microfractures of the coal Decomposition moisture: water held within the coal's decomposed organic compounds Mineral moisture: water which comprises part of the crystal structure of hydrous silicates such as clays
Total moisture is analyzed by loss of mass between an untreated sample and the sample once analyzed. This is achieved by any of the following methods; 1. Heating the coal with toluene
2. Drying in a minimum free-space oven at 150 °C within a nitrogen atmosphere 3. Drying in air at 100-105 °C and relative loss of mass determined
Methods 1 and 2 are suitable with low-rank coals but method 3 is only suitable for high-rank coals as free air drying low-rank coals may promote oxidation. Inherent moisture is analyzed similarly, though it may be done in a vacuum. Volatile Matter Volatile matter in coal refers to the components of coal, except for moisture, which are liberated at high temperature in the absence of air. This is usually a mixture of short and long chain hydrocarbons, aromatic hydrocarbons and some sulphur. The volatile matter of coal is determined under rigidly controlled standards. In Australian and British laboratories this involves heating the coal sample to 900 ± 5 °C for 7 minutes in a cylindrical silica crucible in a muffle furnace. American Standard procedures involve heating to 950 ± 25 °C in a vertical platinum crucible. These two methods give different results and thus the method used must be stated. Ash Ash content of coal is the non-combustible residue left after coal is burnt. It represents the bulk mineral matter after carbon, oxygen, sulphur and water (including from clays) has been driven off during combustion. Analysis is fairly straightforward, with the coal thoroughly burnt and the ash material expressed as a percentage of the original weight. Fixed Carbon The fixed carbon content of the coal is the carbon found in the material which is left after volatile materials are driven off. This differs from the ultimate carbon content of the coal because some carbon is lost in hydrocarbons with the volatiles. Fixed carbon is used as an estimate of the amount of coke that will be yielded from a sample of coal. Fixed carbon is determined by removing the mass of volatiles determined by the volatility test, above, from the original mass of the coal sample. Chemical Analysis Coal is also assayed for oxygen content, hydrogen content and sulphur. Sulphur is also analyzed to determine whether it is a sulfide mineral or in a sulfate form. This is achieved by dissolution of the sulfates in hydrochloric acid and precipitation as barium sulphate. Sulfide content is determined by measurement of iron content, as this will determine the amount of sulphur present as iron pyrite. Carbonate minerals are analyzed similarly, by measurement of the amount of carbon dioxide emitted when the coal is treated with hydrochloric acid.
Calcium is analyzed. The carbonate content is necessary to determine the combustible carbon content and incombustible (carbonate carbon) content. Chlorine, phosphorus and iron are also determined to characterize the coal's suitability for steel manufacture. An analysis of coal ash may also be carried out to determine not only the composition of coal ash, but also to determine the levels at which trace elements occur in ash. These data are useful for environmental impact modelling, and may be obtained by spectroscopic methods such as ICP-OES or AAS Physical and Mechanical Properties Relative density Relative density or specific gravity of the coal depends on the rank of the coal and degree of mineral impurity. Knowledge of the density of each coal ply is necessary to determine the properties of composites and blends. The density of the coal seam is necessary for conversion of resources into reserves. Relative density is normally determined by the loss of a sample's weight in water. This is best achieved using finely ground coal, as bulk samples are quite porous. Particle size distribution The particle size distribution of milled coal depends partly on the rank of the coal, which determines its brittleness, and on the handling, crushing and milling it has undergone. Generally coal is utilized in furnaces and coking ovens at a certain size, so the crushability of the coal must be determined and its behavior quantified. It is necessary to know these data before coal is mined, so that suitable crushing machinery can be designed to optimize the particle size for transport and use. Float-sink Test Coal plies and particles have different relative densities, determined by vitrinite content, rank, ash and mineral content and porosity. Coal is usually washed by passing it over a bath of liquid of known density. This removes high-ash content particles and increases the saleability of the coal as well as its energy content per unit volume. Thus, coals must be subjected to a floatsink test in the laboratory, which will determine the optimum particle size for washing, the density of the wash liquid required to remove the maximum ash content with the minimum work.
Float sink testing is achieved on crushed and pulverized coal in a process similar to metallurgical testing on metallic ore. Abrasion Testing Abrasion is the property of the coal which describes its propensity and ability to wear away machinery and undergo autonomous grinding. While carbonaceous matter in coal is relatively soft, quartz and other mineral constituents in coal are quite abrasive. This is tested in a calibrated mill, containing four blades of known mass. The coal is agitated in the mill for 12,000 revolutions at a rate of 1,500 revolutions per minute. The abrasion index is determined by measuring the loss of mass of the four metal blades. Special Combustion Tests Specific Energy Aside from physical or chemical analyses to determine the handling and pollutant profile of a coal, the energy output of a coal is determined using a bomb calorimeter which measures the specific energy output of a coal during complete combustion. This is required particularly for coals used in steam-raising. Ash Fusion Test The behavior of a coal's ash residue at high temperature is a critical factor in selecting coals for steam power generation. Most furnaces are designed to remove ash as a powdery residue. Coal which has ash that fuses into a hard glassy slag known as clinker is usually unsatisfactory in furnaces as it requires cleaning. However, furnaces can be designed to handle the clinker, generally by removing it as a molten liquid. Ash fusion temperatures are determined by viewing a molded specimen of the coal ash through an observation window in a high-temperature furnace. The ash, in the form of a cone, pyramid or cube, is heated steadily past 1000 °C to as high a temperature as possible, preferably 1600 °C. The following temperatures are recorded; • • • •
Deformation temperature: This is reached when the corners of the mould first become rounded Softening (sphere) temperature: This is reached when the top of the mould takes on a spherical shape. Hemisphere temperature: This is reached when the entire mould takes on a hemisphere shape Flow (fluid) temperature: This is reached when the molten ash collapses to a flattened button on the furnace floor.
Crucible swelling index (Free Swelling Index) The simplest test to evaluate whether a coal is suitable for production of coke is the Free Swelling Index test. This involves heating a small sample of coal in a standardized crucible to around 800 0celsius. After heating for a specified time, or until all volatiles are driven off, a small coke button remains in the crucible. The cross sectional profile of this coke button compared to a set of standardized profiles determines the Free Swelling Index.
