Crusher:
Crushers which used to crush the big mass and changed to small one.
Types of crushers: Jaw, Hammer, Rotary, Impact,
At the beginning, the primary mines, materials transmitted to the crusher section. usually under the crushers there is a screen which the remain of mass stones located on it. The suitable stones with suitable dimensions passed by the screen, arrived at store hall and the great parts which remain on the screen for pre-crushing return to crusher. In addition to the materials chemical analysis, separated of miner the crusher’s chemical percent compound determines analysis and registered by the Geo-Scan by X-Ray radiation or as manual sampling in fixed time period.
The qualification control department by these data considering try to determines a uniformity feeding.
Factory’s crusher presentation:
The factory crusher contains of two separate hoppers for alluvium and limestone charging which by quality control lab view, the charging percent of each sample to the crusher is adjustable. After passing over a rolling hopper and section separation of that by grading production, materials leading to the crushing section of crusher and crushed by the impacts of rotating rotor and passed by the crushers adjustable outfall.(The outfall adjusted by the designs and operation principles)
Crusher’s chipped as well as hoppers passed materials leading to store hall by a conveyor belt. Using of hopper before crusher and prevention of grading product range, caused arising the crushed capacity up to 1200 ton/hr and energy consumption optimization.
Factory’s crusher specification:
Designer: HAZEMAG
Type: impact crusher
Design: AP-PM 16622 GSK
Capacity: 1100ton/hr
Greatest entrance part dimensions: 0<D<1000cm
Production grading: 0<D<8cm
Maximum motor consumption power: 500 KW
Store hall:
For the purpose of storage and mixing raw materials and processing a uniformity mix in cement production industry, the store hall is designing and establishing.
In addition to the some days, raw materials storage, for uniformity activities of kiln and production line by different methods of storage and removal, plays an important role in raw materials preparation.
As mentioned in the preparation and uniformity of raw materials the storage and offstage method are fulfilled this goal. For this purpose, we use of homogeneity band method. In this method, a special machine equipped with a movable arm moved on rails on deposit (depot) length and moved up the prepared materials. By using of movable arm discharged at the side of moving. Therefore, there is a pile as vertical layers of materials. Now, if the materials removal as vertical cross cut, the applied part contains of all layers.
In store hall primary materials accumulation formed by stacker and its removal by reclaimer. It is necessary to mention, which at removal time by reclaimer, stacker can prepare on the other side of store hall a new pile. During the time which reclaimer completes a pile, the other pile prepared and changed its position, the preparation of materials continued.
Factory’s store hall presentation:
Type: linear hall
Dimensions of store hall:
Length: 280m
Width: 55m
Height: 20m
Capacity: 6000tons (contains of two pie 3000tons)
Factory’s stacker specifications:
Designer: SCHADE
Design: Stacker A1400-21.5
Capacity: 1400ton/hr
Factory reclaimer specifications:
Designer: SCHADE
Design: bridge type reclaimer B700-35S
Capacity: 700Ton/hr
Raw mill:
Generally in cement production process we need materials powdering in two steps:
1- Raw mill before burnt
2- Clinkers and gypsum mixed in cement mill production after burnt.
In cement industry, about 75% of all energy consumption used for milling and powdering, which 2-20 percent is useful and remain wastes as heat, vibration and noise.
For preparation of materials with a suitable measurement and uniformity compound for burnt department, after crushing and storage in store hall and improvement increase entered the mill for abrasion.
In different industries raw materials mills industries, generally divided in two types dry and moist (wet) which based on crushed materials in next process activities kinds, choosing one of those two kinds of mills. In cement industries, the used mills mainly are of dry kind.
Rotating and rolling mills are of dry mills kinds.
By considering usage of all two kinds of rotating and rolling mills in factory (rolling mill for raw materials abrasion and rotating mill for cement abrasion) separately, we indicate of those mills.
Rolling mill:
Rolling mills are of all kinds, but their specification are rolling which in circle direct on the bed of materials which situated on a vertical circular level rotating around its axial and by press power powdering and crushing the materials in cement industry.
The vertical rotating mill is a suitable chooses for drying, abrasion and raw materials separation. Nearly the consumption power in these mills are as same as the utilities equipment consumption power, as separator, fan and ,… meanwhile, in closed circuit shell mills as a result of body weight and shells moment, 80 percent of all consumption power related to mill main motor and this parameter increase to 90 percent in open circuit mills.
The following are the other advantages use of rolling mills:
1- Energy waste, and voice pollution and as a result higher efficiency
2- Weather current less press shortage of move hot weather volume, and as a result material powdering capability with more ratios humid. All abrasive unit contains of sealing system, feeders, separation equipment of entrance feeding and iron.
Vertical rolling mill accompaniment external material circulation system, Hot gas current, cyclonic dust catcher for product collection, or rotating air valve or sealing gates in feeding entrance for prevention of pseudo weather.
Factory’s raw material mill presentation:
By considering the percent compound and raw material analyses, quality control fairs with a suitable measurement of primary materials managing the mill feeding.
In this straight Mill feeding through 4 hoppers one related to the pepont of store hall materials and three other hoppers are related to the raw material chemical compound correctives. At present the corrective hoppers contains of the following items:
1- Alluvium with high titration
2- Alluvium with low titration
3- Iron
In purpose of burnt necessary feeding provision, using a suitable weight percent of primary materials by using of separate scaling system for each hopper.
Feeding transmit to mill by a rubber conveyor and powered in mill central try through entrance duct, moved to the abrasive area and crushed and powdered on the rollers press or effect. Material movement toward bed, in addition to the engineering design of roller and try by ratio of rollers, diameter and the max entrance feeding measurement.
The crushed material after passing of abrasive region divided in two sections.
1- The light material which the climber gas current in the mill of nozzle ring overcame to the weight force and leading them to separator.
2- The more great crushed materials which fall to the down mills try and form the external circulating bar and after coming out from the mill by a climber, returns to the abrasive region through the feeding way.
The entrance separator material in effect of particles, weight gas current climber force and centrifuge force by separator, divides in two groups of production as particle. Production leading to cyclone by separator with gas current and after parting of gas current, by a transmitter by air current for more homogenization and powdering, leading to raw – material silos. The greater going toward hopper and for re-crushing (re-abrasion) under separator, forming the mills circulation leads and entered in abrasive part.
Raw-material mill specification:
Design: PFEIFFEERGEBR
Type: Vertical mill
Model: MPS 5000B
Capacity: 310 ton/hr
Grading of feeding: 0-50mm, 3%>50mm>80mm
Production grading: 12% R0.090mm max
Necessary gas volume: 371,810Nm3/hr
Maximum of mills motor power: 3300KW
Maximum of mills motor fan power: 3550KW
Of special MPS specifications in compression to the other rolling mills for raw materials abrasion.
We can points out the process, engineering and mechanical designing. These mills types have more special abrasion potential, rotating trays low speed, low air current and from mechanical view max of mills motor fan potential more strength against abrasion.
Factory raw material silos specification:
Design: IBAU
No.: 2
Volume: 7922m3
Capacity: 8000ton
Preparation of kilns feeding:
After preparation of raw material It is the turn of kilns feeding. It has different styles, and on base of this the different cement types production classified. There are methods, which we point it out later on.
1- Humid method:
They full the base in of water and add the primary materials by a specialized ratio. An interchange mechanical arm formed the material mixture and prevention of sediment. Of course, it is possible to use of compressed air blowing of basin.
We sampling of the present of the grout, and analysis in the lab, to determine the material ratio, systematically, material deficiency and grouts mixture is determined and by using of silos add the necessary materials up to efficiency rating until the grout presents with a special composition they transmit the prepared (ready) grout to the cement burnt kiln.
2- The Semi humid method:
In this method, the achieved grout of humid method, before passing to the kiln press some filters or accordance for drying the result, was a thick which after cutting formed as small cylinder for burning in kiln.
3- The Semi dry method:
4- Dry method:
Raw mill kiln and clinker production:
1-Vertical kiln:
The vertical kiln is a standing cylinder, usually diameter 2-3m and height 7-10m, which inner surface have covered by refractory. Feeding kiln charges by a percent of coal powder from up. The coal By blowing and neighboring of fire, kiln fired and prepares the necessary temperature. What is discharged as output of the kiln is called clinker. In this case, this kind has a very simple system and also a simple service unformality of productive clinker, high personnel expenses, less production and expensive consumption are theirs important faults. Therefore the vertical kiln, gradually delete of factory’s production line and change by horizontal rotary kiln.
2- Horizontal rotary kiln:
The rotary kiln is a metal cylinder by diameter 3-5m and a suitable length, sometimes up to 160m, This kiln axial has a small angle to horizon which the charging material on base of rotating movement and suitable moved to down. The kilns necessary heat provides by a torch which installs at the end and prepares the warm circulation and heat from the end up to beginning. As the heat in the kiln is very high for prevention of heat transferring to the kilns body, cover the inner surface by refractory. In case which the kiln turns off the very high heat causes the heat shock and destroys the kilns inner part. Therefore as far as possible except for kiln repairment or the other necessary cases. Prevention of energy wasting is a reason, which designers try their best for new burnt systems efficiency improvement. As we mentioned in horizontal rotary kiln, there are two opposite current.
1- Material current from up to down
2- Hot air current from down to up
Clinker discharge by kilns down and warm air by kilns up, cause wasting a great amount of energy and kilns heat. The necessarily of this phenomena opposition, leading to different methods invention and equipments adding as preheater, calciner, cooler, …
Preheater:
Preheater formed of some important container cone shaped (cyclone) which install at the up kilns entrance and material past be from kilns entering.
The hot outlet air over the kiln has passed through cyclones. This warm air current causes the raw material changes warm and dry. Therefore, by decreasing the heating region in kiln, as to this ratio the kilns length decreases.
Preheater equipped to a blowing fan and blades in the cyclones outlet which the air current after speed adjustment by fan, turbulent after blades impact, floating the primary material and warm it. The following are the advantages of preheater high efficiency(about 90%) and kilns entrance efficiency up to 750 Kcal/Kgclinker possibility of applying the more smooth material and effect on calcinations thermodynamics decrease of moisture level, productions quality improvement and , … and disadvantages of the preheater is structure high, height pressure loss and necessity to more energy consumption in preheater fan.
Precalciner:
Pre-calciner designs as pre one base of more use of waste energy in the strait of kilns outlet gases.
Pre-calciner contains one or several torches which has installed between pre-heater and kiln and some percent of materials calcinate by heat effect. Following, kilns length decreases and conservatism in energy and expend.
Cooler:
A noticeable waste section of kilns energy and heat, because of clinkers exit inconsumable kilns exit clinker with a temperature more than 1000 centigrade and also prevention of clinkers formed phases return for its quality increase, all belongs to a systems applying called cooler. Coolers have different and winds and their general system are as follow, which clinker entrance the cooler with a very high temperature, and affected by the cool air current on the other hand, the air which increased the degree because of clinkers touch leading to the kiln and decreases the necessary energy level for heating.
Electrostatic filter:
After passing of pre-heater and calciner the kilns outlet gases, finally penetrate in atmosphere. the gases contains of an amount of small particles, which caused the existing environment pollution, if they are not recovery. we use of all kinds of filters for separation of these particles.
Electrostatic filter is one of these filters. In these system, some metal plates with positive electrostatic bar, stands against the outlet gases. The suspended particles, by a high-voltage of electrical current, receives the negative bar attracted by the plates with positive bar. When the thickness of the particles showed a fixed limits, they clean by the vibrating plates. The achieved particle by consuming capability returned to the kilns feeding. The outlet gas of pre-heater, which submitted the main part of its temperature to the materials, cooled up to 300 degree centigrade. It’s necessary to decrease the gas temperature, because of preventing for filters thermal equipments damage and arising the dust collecting efficiency.
First we pass the gas over the cooling tower and by washing with a suitable amount of water, decrease the temperature up to 150 degree centigrade, and then entering in dust catching system(Electro filter).
Of course, except the electrostatic filters, the other filters such hybrid filters also, used which the cooling processes of entering gas is different.
The outlet gases dust catching of burning system, beside the economical cases, are very important because of bio-environmental reaction.
Bypass system:
Some volatile elements such as chloride, potassium oxide, sodium oxide, sulfur or sulfate in kilns feeding or burning caused a cycle of such materials formation in the thermal environment of evaporation and condensation, rising the material viscosity in these cycles caused some difficulties such as jamming entrance, calciner and the ending cyclones and affected on the burning thermodynamic, refractory abrasion and …
The necessity of viscosity rising prevention of such elements caused sublimation such as by pass designing system. this system, have exited a percent of kilns exit gas which usually suction.
After gas cooling and sublimation the mentioned elements the clean weather entering to the environment and the hard materials which generally have a very soft grading going out of the system.
Anyhow, we try to fix the volatile materials viscosity in burnt system. the exhaust gas level of burning system by bypass could be 10-70 percent of the exhaust gas through the Kiln.
The presentation of the factory’s burnt system:
Momtazan cement burnt system by applying the best experience and technology of German designer, made and installed and predicted all mentioned cases in the strait of energy consumption trends and by optimizing of mentioned aims continued their process.
Designer: KHD HUMBOLDT WEDAG
Kilns length: 52m
Kilns diameter: 4.4m
Kilns inclination: 3.5%
No of feet: 2
Capacity: 3300ton/day
Turning degree: 0.5-3.4 rpm
Motor consumption power: 470KW
Torch design: Pyro jet burner HPJ/240
Torch thermal power: 237.6*10^6KJ/h
type of consumption burnt: Natural gas – Fuel oil
The torch volume capacity in fuel oil consumption time: 6900NM3/h @P=3bar, T=15degree centigrade
The torch weight capacity in fuel oil consumption: h@p=40bar, T=130°C, Velocity: 2°E/5700nm3
By pass system:
Consist of pocket filter(Bag filter), cooling fan
Filter capacity: 50000m3/h
Exhaust gas rate towards bypass 5% Kilns exhaust gases.
Pre heater:
Design: 5steps monopole by two cyclones at the first stop
pre heater consumption fan power: 2000KW
Calciner:
Design: Pyro top ( The advantage of this calciner is pointing out to the complete mixing of burnt and materials, optimizing gases mixing and decreasing of NOX )
Torch design:
PYRO JET burner HPJ/320
Torch power:320*106kj/h
