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After more than ten years of rapid development,the cement industry has entered a new historical development period,and the output has reached the highest level in history.

How to take the lead in the new normal of excess capacity and fierce competition?Need to be familiar with the challenges that cement industry faces above all!

You want to steer the direction of cement development

-Maintain the profitability of the company

-Optimize the energy structure,reduce the energy consumption of tons of cement and reduce the energy cost.

-Improve management level,improve production efficiency and reduce variable cost.

-Extend the life cycle of fixed investment and amortize the fixed cost of tons of cement.

-Improve product quality to win market reputation.

-Reduce greenhouse gas emissions,protect the safety of people and the environment,and fulfill corporate social responsibility.

We can help you achieve your goals

As a professional motor control intelligent product provider,Powtran Technology combines experience in intelligent manufacturing,distribution and automation,process control and energy efficiency management to create high-quality overall solutions for cement industry users.

Not only can meet your production needs,perfect solution of engineering and maintenance problems,but also let your production with automation,information wings,so that your factory more healthy,more intelligent,more efficient,you can focus more energy on the core business areas,smoothly achieve the goals.

＞150

More than 150 countries have cement industries

Number one in the world

In 2018,China’s cement output was 2.184 billion tons,ranking first in the world and accounting for more than 60% of the world’s total output.That’s 33.5 times the 65.24 million tons in 1978!

Process flow and modification plan of cement system

1) Introduction of cement production process

Cement production and manufacturing mainly through crushing,storage and pre-homogenization,grinding,raw material homogenization and storage,calcination,cement grinding these important processes.A grinding mill is a metal cylinder of the mill with a huge inner metal shield,in which there is a lot of spherical steel.As the mill is rotating,these balls grind the raw material into small particles,called raw material.

Calcination means that,after homogenization,raw material are transported through a cyclone tube system called a preheater,and after gradual geothermal treatment temperature up to 900℃,they enter a rotary kiln,which bakes the materials.The kiln body is a long cylinder with a length of 50~150m and a diameter of 3~50m.The inner wall of the cylinder is lined with firebricks.The rotary action of the kiln and its driving Angle make the material move towards the outlet,and the temperature rises to 1400℃.As a result of this process in the kiln,raw materials are transformed into granular hard materials,called clinkers.Clinker is the main component of cement. Clinker determines the quality of the final product.Cement as the finished product is a very fine powder,which is required to produce a mixture of clinker,gypsum,and some natural and man-made materials(e.g.,volcanic ash).A cement mill is similar to a raw mill in that the mixing of materials is strictly controlled and continuously monitored.The level of compressive strength of the type of cement and the most important characteristic depends on the chemical composition of the clinker,the duration of the mill and the addition and non-addition of various additives.The process flow chart is shown in the attached drawing.

1) Retrofit scheme

Conversion transformation of vertical kiln air supply system

(1) Operation of the fan

Generally,the regulation mode of low-pressure vertical kiln fan is the air door regulation method,and the air supply regulation mode of Roots fan is the exhaust regulation or return regulation.The air supply regulation of the centrifugal fan is regulated by the air inlet valve.When working normally,the opening degree of the value is about 70%~90%,which means a part of the air volume is wasted.The design of the blast system is based on the maximum air supply demand(maximum working condition plus standby),and the operation condition of the blower is also the same (that is,based on the maximum air supply demand of a single machine).In be used actually have a lot of time fan needs to be adjusted according to actual working condition,the traditional way is adjusted by the switch throttle,this way of regulating the increase for the wind system of throttling losses,when start the fan will also have the impact current,and to adjust the system itself is also a phased,adjust speed is slow,reduce the loss of the ability is limited,also make the system work in fluctuation state.By installing energy-saving devices in the blower,these problems can be solved once and for all,the working state of the system can be gentle and stable,and the inverstment can be recovered through frequency conversion and energy saving.

(2) It can be known from the general experience of fan use:under the operating state of power frequency(AC380V/50Hz),the load of the fan using the damper(air valve)to regulate the air volume fluctuates between 15% and 100% during the use process;The smaller the load,the greaster the throttling loss of the damper(valve) and the lower the fan efficiency.However,the throttle loss of the throttle is almost not existed when the variable frequency regulation is changed.At the same time,the variable frequency device adopts soft starting mode and there is no start impulse current.For the factory power system with limited distribution capacity,the safety factor can also be improved.

(3) After transforming frequency conversion for the wind system is on the basis of retain the original for the wind system to increase a set of frequcency conversion circuit and original circuit in parallel with,form a two-circuit convertible control system,and the frequency converter speed regulating device installed in the position of the kiln,by adjusting the rotational speed of the motor(fan)to adjust when sintering with air volume.Its features:

·Good effect of electricity saving.Since the power consumed by the motor is directly proportional to the third square of the motor speed,most of the time after the modification of the motor running at about 35-43Hz can meet the required air volume,and the power saving rate is more than 25%.

·With soft start function,reduce the load intensity,extend the service life of the equipment,small start current,improve the safety factor of electricity and reduce the capacity of the power grid;

·Regulating air volume accuracy,timely and convenient;

·Close the return air outlet or exhaust outlet to reduce cement dust pollution.

The test results of a Certain Cement Co.,Ltd. In Dalian after conversion of general transmission technology are shown in Table 1:

U cement powder preparation system

The working principle is according to the production of cement label different,adjust the speed of powder separator and powder fan,thus select different fineness of cement products.To adjust the number and Angle of the fan blades of the old type of powder separator,the fineness of powder selection required is achieved through comparative test.The new powder system is divided into powder separator and powder separator fan two parts,powder separator by slip (electromagnetic speed regulating)motor speed,powder separator by adjusting the wind plate angle to adjust the wind volume.These two kinds of systems ave the disadvantage of complex operation technology,poor regulation accuracy and waste of electric energy,especially the slip motor not only cost electricity,but also because of the serious dust in cement manufacturing environment,the failure rate is particularly high,and the maintenance is much and difficult.After frequency conversion transformation,whether it is the old system or the new system,the motor can be adjusted to a specific speed can select the particle of fineness required,in the energy saving at the same time also achieved a specific speed can select the particle of fineness required.At the same time,it also achieves continuous and automatic production.It not only improves the labor efficiency,but also reduces the labor intensity,and the comprehensive benefit is obvious.The analysis after the transformation of a cement factory is shown in Table 2:

U machine vertical kiln unloading system

In order to balance feeding,air supply and unloading in the cement sintering process,slip motor(electromagnetic speed-regulating motor) is generally used as the power of the tray type unloading device in vertical kiln,which not only fails to meet the protection level of cement production.

The field needs,and in the same output speed under the condition of power consumption is also higher than asynchronous motor about 20%;When the speed is reduced,the slip motor has lower efficiency and higher power consumption compared with asynchronous motor.Therefore,the variable frequency speed contorl system is used to replace the slipe speed control,overcome the above shortcomings,the speed contorl performance is far higher than the slip speed control motor,at the same time,the maintenance cost is also greatly reduced,has been widely used in the industry,cement co.,Ltd. And other unloading process conversion transformation.The energy-saving effect is shown in Table 3.

U into a ball system

The pelleting process of raw material is one of the key processes that affect the quality of cement clinker sintering,in which the propoertion of water and material directly affects the pelleting quality.After the application of frequency converter,the speed of pellet-forming prefeed pump can be stepless regulated by tracking the raw material supply quantity,so as to realize the full automatic closed-loop control.The combination of material and water is stable,the ball forming effect is good,and the quality of cement sintering is greatly improved.

U Raw material homogenized feeding system

After the transformation of the system with a frequency converter,the feeding motors at all the feeding ports are speeded up stepless with a frequency converter,and proportionally feeding is carried out to improve the homogenization effect.

U Other equipment

Through analysis and comparison,the power saving rate of drying machine,drying fan,crusher and other slip speed regulating motors can be above 20% after the conversion transformation.

The application of frequency conversion technology in cement manufacturing industry can not only save energy,reduce the workload of maintenance and repair,reduce the cost of cement production,but also stabilize the process to improve the quality of cement.The application of frequency conversion technology in electromechanical equipment and production line of various industries is an inevitable need for the production development of enterprises.More and more enterprises realize the competitive advantages brought by the application of frequency conversion technology,and transform their traditional equipment with frequency conversion,so as to promote the development of enterprises.It not only improves the equipment efficiency,but also meets the requirements of the production process,and thus greatly reduces the equipment maintenance costs,and also reduces the shutdown period.The direct and indirect economic benefits are very obvious.

The one-time investment in the equipment can usually be fully recovered in 9 to 16 months of production.

2) Application of new dry cement production line

In the new dry cement production line,the direct use of transducer or motor energy saver can save energy and reduce consumption.

Dalian cement manufacturing Co.,Ltd.3000 tons of new dry cement clinker production line,using general transmission technology motor environmental protection energy-saving a total of 18 sets.

Based on the conservative estimate of 25% power saving for a production of 300 days per year,24 hours per day,the electricity saving and savings are as follows(80% rated power for normal operation):

Power saving:1559*80%*25%*24=7483(kWh)/day

30=7483*224496(kWh)per month

224486(kWh)/month*October(300 days)=2244860(kWh)/year

Calculated at 0.5 yuan per KWH,the annual electricity saving rate is:

2244860*0.5=11224.3 yuan means the annual electricity saving rate is 1.1 million yuan.

Cement industry belongs to the industry of high energy consumption,high pollution,low value-added,we have a wealth of solutions in intelligent manufacturing,can help you achieve modernization,greatly improve your competitiveness and achieve sustainable development!