Production procedure for cement

cement plants in malaysia

cement plants in malaysia

In the days of Egypt as well as Greece, sintered as well as ground lime or even plaster was utilized as cement with regard to civil engineering as well as construction. In the actual 19th century, port land cement was manufactured in England. This guide covers energy preservation in portland concrete production.

A cement production plant includes the following  processes.

  • Raw materials process
  • Clinker burning up process
  • Finish milling process

The raw material process and also the clinker burning procedure are each classified to the wet process and also the dry process.

Within the wet process, recycleables other than plaster are crushed to some diameter of around 20 mm with a crusher and mixed within an appropriate ratio utilizing an automatic weigher, because shown in Fig. 1. After that, with water additional thereto, the mixture is actually further made finer with a combined tube mill having a diameter of two to three. 5 m along with a length of 10 in order to 14 m into slurry having a water content associated with 35 to 40%. The slurry is place in a storage tank having a capacity of a number of hundred tons, mixed to become homogenized with the actual corrective materials, and it is sent to the rotary kiln with regard to clinker burning. Within the wet process, the slurry could be easily mixed but a lot of energy is eaten in clinker burning because of water evaporation.

Within the dry process, crushed recycleables are dried inside a cylindrical rotary drier using a diameter of 2 m along with a length of regarding 20 m for instance, mixed by a computerized weigher, ground and put into storage tanks. The resultant blend is further mixed to create the ingredients standard, and sent to some rotary kiln with regard to clinker burning.

These processes tend to be selected with consideration directed at properties of recycleables, costs of energy, conditions of location yet others. For the moist process, plant construction cost is quite low and high-quality items are manufactured very easily. On the additional hand, the dry procedure consumes less energy and it is running cost is gloomier.

The progress associated with technology is, nevertheless, eliminating the variations in quality between products in the above processes, while needs with regard to energy conservation are becoming increasingly strong. Within future, the wet process won’t be employed positively.

Characteristics of one’s consumption in concrete production

Energy usage

The cement industry is considered an energy-intensive industry as well as steel, paper as well as petrochemical industries. The percentage of one’s cost in portland concrete production cost is actually 20 to 30%. When the energy cost is actually reduced, the production cost is decreased, resulting in increasing the business’s profits.

Ninety percent or even more of fuel is actually consumed for clinker burning up. About 40% of energy is consumed with regard to finish grinding, along with a little under 30% every is consumed through the raw material process and also the clinker burning procedure. The finish milling process mainly consumes energy for the mill, and the clinker burning up process mainly for that fan.

The rawr materials grinding process consumes a sizable volume of power for that mill and enthusiast.

The Japanese concrete production process is mainly occupied by SP as well as NSP kilns and coal can be used as fuel, so the ratio of energy consumption by the actual clinker burning procedure is high. Inside a plant mainly utilizing a wet process kiln, the conclusion grinding process consumes power inside a larger quantity compared to aforementioned example. When this occurs, energy conservation measures will be taken by-focusing about the clinker burning process for that fuel consumption and about the finish grinding process for that electric power usage.

Raw material procedure

Wet process

Since recycleables can be homogenized and also the mixing ratio could be corrected after milling, this process is not at all hard.

Dry process

Fig. four shows three procedures a, b as well as c. Raw materials received with a plant contain a tiny bit of water. Limestone consists of 2 to 5% associated with water and clay-based about 5 in order to 10%. The dry process must evaporate water whenever grinding. In Fig. four. process a will get an independent clothes dryer to evaporate drinking water, and the dryer can be a rapid dryer or even impact dryer having a disintegrating or crushing function rather than the rotary dryer because illustrated.

In Fig. four, process b is really a closed circuit milling process combining a good air separator along with a ball mill or even lube mill, which will get drying function. The above mill and separator can be found in several types.

Within Fig. 4, process c is a good example of vertical roller mill.

For drying, exhaust gas in the kiln and preheater can be used, but sometimes the hot gas electrical mill is installed for some time of commissioning from the plant and for some time of year when water found in raw materials raises.

Clinker burning procedure

Wet process

An average example of the actual wet process is really a straight cylindrical type kiln using a length of regarding 40 times from the shell’s inner size, which is often known as a long affordable kiln, installed by having an inclination of two. 5 to 4% as well as slowly rotated from 0. 5 to at least one. 5 rpm. Raw material is actually slurry containing 37 to 40% associated with water and fed in the upper end from the kiln, while fuel is actually blown in in the lower end from the kiln.

At the actual raw material inlet, a chain drape zone is set up extending to 20 to 25% from the overall length to assist dry the slurry. The actual hot clinker, that has been sintered within the kiln, is delivered to the cooler and cooled off to 80 in order to 100°C. Hot air in the cooler is effectively used since the secondary air for combustion within the kiln.

Semi-dry procedure

The semi-dry process is really a special example from the dry process and runs on the Lcpol kiln or even shaft kiln. Within either kiln, the raw material ground within the dry process is actually shaped into pellets along with diameter of 10 in order to 15 mm, to ensure that about 13% associated with water is additional.

In the case from the Lepol kiln, the pellets tend to be dried and preheated once through the movable grate prcheater proven in Fig. 6 and fed to the kiln. This system applies for the very first time in the cement plant an idea of separating the actual raw material preheating process which was previously effected in the actual kiln and preheating with a separate device along with high thermal effectiveness. Then, the Lcpol kiln offers lost its position whenever a kiln with suspension preheater (SP kiln) had been introduced but warrants special mention because it motivated energy conservation activity within the cement plants.

Within the shaft kiln, energy (coke, oil coke or even anthracite) is added within the pelletizing process. Just about all processes of drying out, sintering and air conditioning are effected within the vertical movable mattress. This concept have been conducted before the actual rotary kiln had been spread and, lately, as shown within Fig. 7, the shaft kiln having a continuous discharging function installed in the furnace bottom is principally used in Indian and China. This kiln’s benefit is heat economy it has disadvantages because the poking work within the furnace needs to be repeated to retain a well balanced combustion state as well as nonuniformity of quality can’t be avoided.

Dry procedure

In the dried out process, there would be the dry long kiln, the actual short kiln along with boiler, the SP kiln and also the NSP kiln.

The dry long kiln is principally used in the actual Near and Center East where rainfall falls less as well as alkaline components within raw material tend to be large; its characteristics act like the wet procedure long kiln. Within Southeast Asia, Central and South usa, and North The united states, the wet procedure long kiln is principally LlSOd.

Fig. 8 exhibits a transition associated with production systems within Japan. It is visible that the moist process is rapidly replaced through the dry process. It reflects growing needs for power conservation and suggests what the real cement plant for the future should be.

A current large NSP process includes a heat consumption rate around 750 kcal kg#cl and it is superior to all of the conventional sintering procedures.

In this link, the wet procedure long kiln might have a heat consumption rate of just one. 500 to 1, seven hundred kcal/kg? cl except in certain special cases, and also the semi-dry process kiln might have 1, 000 to at least one, 200 kcal/kg*cl.

Complete grinding process

The conclusion grinding process is actually roughly divided in to an open signal grinding system along with a closed circuit milling system. The mill used is really a tube mill or even ball mill. Within Fig. 11, “a” exhibits a closed signal and “b” exhibits an open signal.

In the open up circuit mill, the mill shell includes a length of regarding 4 to 5 occasions of its diameter to acquire a prescribed fineness, and also the shell outer walls is sprayed with water to avoid the temperature from the product in the actual mill from increasing. It is additionally possible to spray water to the mill interior however the closest attention needs to be paid so as to not deteriorate the item quality.

In the actual closed circuit mill, the mill includes a length of three times or below associated with its diameter in order to accelerate the passage from the product. The separator works like a cooler for the product along with its function as classifier for that product.

Promotion of one’s conservation technique

Energy conservation within industrial sectors starts in the software including procedure control and procedure control, then extends to the field of equipment including equipment enhancement and process enhancement. Generally, energy conservation efforts could be classified into the next three steps:

Step one – Good house cleaning

Energy conservation efforts are created without much gear investment, including elimination from the minor waste, overview of the operation standards within the production line, far better management, improvement associated with employees’ cost awareness, group activities, as well as improvement of procedure technique.

For instance, such efforts include management to avoid unnecessary lighting from the electric lamps as well as idle operation from the motors, repair associated with steam leakage, in addition to reinforcement of warmth insulations.

Step two – Equipment enhancement

This is the actual phase of improving the power efficiency of the gear by minor modification from the existing production line to supply a waste warmth recovery equipment along with a gas pressure recuperation equipment or through introduction of effective energy conservation gear, including replacement through advanced equipment. For instance, energy conservation efforts with this step include a highly effective use of the actual waste heat recuperation in combustion furnaces and introduction from the gas pressure recovery mill within the iron and metal works and waste materials heat recovery electrical mill in cement grow.

Step 3 — Process improvement

This really is intended to decrease energy consumption through substantial modification from the production process by itself by technological improvement. Needless to state, this is along with a large equipment expense. However, this is associated with modernization of the procedure aimed at power conservation, high high quality, higher added worth, improved product deliver and man energy saving.

Energy administration

Energy consumption price

Fig. 13 as well as Fig. 14 show a big change of energy usage and energy consumption rate in most cement plants within Japan.

Comparing the time when the energy consumption rate reduces sharply in Fig. 12 along with Fig. 8, il coincides using the period when the actual NSP system had been introduced. In exactly the same period, the energy consumption rate increases once after which continues to reduce, remaining stable for many period from 1978. With this period, fuel had been changed from oil to coal. The improvement next period may derive from the active adoption of the roller mill since the raw material mill.

Energy conservation method in cement manufacturing process

Raw mill

Since the wet process includes a simple system, you should enhance the operation efficiency from the mill itself. The mill performance depends upon various factors. As well as, among them, the fundamental items are distributed by the following empirical formulations, for example.

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