Application Note: Cement Industry

Condition Monitoring of Rotating Machines

Cement, ubiquitous binding material has stood tests of geography, climate and other factors in its usage over decades. Its application can be seen everywhere, be it residential buildings, government offices, roads, bridges etc. Cement contributes to almost 15-17% of the cost of construction of any structure.

Cement manufacturing involves aggressive and harsh production conditions due to high dust content in the plant area. This creates an additional onus of accurate and stable measurement on condition monitoring devices. These instruments need to prevent any unplanned shutdown as well as providing long term reliable solutions.

Rotating Machinery is at the heart of cement plants. It is very necessary to run the machine at high efficiency without any trouble. The deterioration in the efficiency of rotating machines cannot be predicted, but with the help of the Vibration Monitoring and Analysis System, this can be properly judged. Vibration Monitoring and Analysis is the easiest way to keep machines healthy and efficient in the long run. This reduces the overall operating cost as well as the down time period, increases plant availability and efficiency of rotating machines. To cope with global competition and pressure, every plant wishes a 95% uptime, hence maintenance planners are moving from reactive maintenance to proactive maintenance

Need for Vibration Monitoring in cement plants

Effective for many root causes such as imbalance, misalignment, abnormal roller bearing, abnormal sleeve bearing, abnormal speed reducer, looseness etc.

Preventing unscheduled downtime

Reducing downtime when machine is down

Extending machine usable time

Preventing failures

Reducing energy costs

Objectives of Vibration Monitoring

Cement industries typically produce portland cement, although they also produce masonry cement, which is also manufactured at Portland cement plants. Portland cement is a fine, typically gray powder comprised of dicalcium silicate, tricalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite, with the addition of forms of calcium sulfate. Different types of Portland cement are created based on the use and chemical and physical properties desired. Portland cement types I - V are the most common. Portland cement plants can operate continuously for long time periods (i.e., 6 months) with minimal shut down time for maintenance. The air pollution problems related to the production, handling, and transportation of Portland cement are caused by the very fine particles in the product.

The stages of cement production at a Portland cement plant is as follows

Procurement of raw materials

Raw milling - preparation of raw materials for the pyro processing system

Pyroprocessing raw materials to form Portland cement clinker

Cooling of Portland cement clinker

Storage of Portland cement clinker

Finish milling

Packing and loading

Cement making process

Raw Material iron, silica,PFA or Bauxite

Primary Crusher Sec Crusher

VMS VMS

Blending Silo Vertical raw Mill

Pre heating tower

Electrostatic Presipitator

ID Fan

VMS

VMS

Kiln

VMS

Gypsum

Grate Cooler

Clinker Silos

VMS

Finishing MillCement storage Shipping

Raw milling involves mixing the extracted raw materials to obtain the correct chemical configuration, and grinding them to achieve the proper particle-size to ensure optimal fuel efficiency in the cement kiln and strength in the final concrete product. Three types of processes may be used: the dry process, the wet process, or the semidry process. If the dry process is used, the raw materials are dried using impact dryers, drum dryers, paddle-equipped rapid dryers, air separators, or autogenous mills, before grinding, or in the grinding process itself. In the wet process, water is added during grinding. In the semidry process the materials are formed into pellets with the addition of water in a pelletizing device.

Raw milling

Motor Fan Vertical raw mill

Fan

Pyroprocessing

Motor

In pyroprocessing, the raw mix is heated to produce Portland cement clinkers. Clinkers are hard, gray, spherical nodules with diameters ranging from 0.32 - 5.0 cm (1/8 - 2") created from the chemical reactions between the raw materials. The pyroprocessing system involves three steps: drying or preheating, calcining (a heating process in which

calcium oxide is formed), and burning (sintering). The pyroprocessing takes place in the burning/kiln department. The raw mix is supplied to the system as a slurry (wet process), a powder (dry process), or as moist pellets (semidry process). All systems use a rotary kiln and contain the burning stage and all or part of the calcining stage. For the wet and dry processes, all pyroprocessing operations take place in the rotary kiln, while drying and preheating and some of the calcination is performed outside the kiln on moving grates supplied with hot kiln gases.

Kiln

Most of the raw materials used are extracted from the earth through mining and quarrying and can be divided into the following groups: lime (calcareous), silica (siliceous), alumina (argillaceous), and iron (ferriferous). Since a form of calcium carbonate, usually limestone, is the predominant raw material, most plants are situated near a limestone quarry or receive this material from a source via inexpensive transportation. The plant minimises the transportation cost since one third of the limestone is converted to CO during the 2pyroprocessing and is subsequently lost. Quarry operations consist of drilling, blasting, excavating, handling, loading, hauling, crushing, screening, stockpiling, and storing.

Raw material acquisition

Fan

Clinker cooling

The clinker cooling operation recovers up to 30% of kiln system heat, preserves the ideal product qualities, and enables the cooled clinker to be maneuvered by conveyors. The most common types of clinker coolers are reciprocating grate, planetary, and rotary. Air sent through the clinker to cool it is directed to the rotary kiln where it nourishes fuel combustion. The fairly coarse dust collected from clinker coolers is comprised of cement minerals and is restored to the operation. Based on the cooling efficiency and desired cooled temperature, the amount of air used in this cooling process is approximately 1-2 kg/kg of clinker. The amount of gas to be cleaned following the cooling process decreases when a portion of the gas is used for other processes such as coal drying.

Motor

Motor

Clinker storage

Although clinker storage capacity is based on the state of the market, a plant can normally store 5 - 25% of its annual clinker production capacity. Equipment such as conveyors and bucket elevators is used to transfer the clinkers from coolers to storage areas and to the finish mill. Gravity drops and transfer points typically are vented to dust collectors.

Conveyor motor

During the final stage of Portland cement production known as finish milling, the clinker is ground with other materials (which impart special characteristics to the finished product) into a fine powder. Upto 5% gypsum and/or natural anhydrite is added to regulate the setting time of the cement. Other chemicals, such as those which regulate flowability or air entrainment, may also be added. Many plants use a roll crusher to achieve a preliminary size reduction of the clinker and gypsum. These materials are then sent through ball or tube mills (rotating, horizontal steel cylinders containing steel alloy balls) which perform the remaining grinding. The grinding process occurs in a closed system with an air separator that divides the cement particles according to size. Material that has not been completely ground is sent through the system again.

Finish milling

Packing and loading

Once the production of Portland cement is complete, the finished product is transferred using bucket elevators and conveyors to large, storage silos in the shipping department. Most of the Portland cement is transported in bulk by railway, truck, or barge, or in 43 kg (94 pound) multi-walled paper bags. Bags are used primarily to package masonry cement. Once the cement leaves the plant, distribution terminals are sometimes used as an intermediary holding location prior to customer distribution. The same types of conveyor systems used at the plant are used to load cement at distribution terminals.

Why do we need Condition Monitoring for fans, motors, mills?

It is now imperative to monitor the plant to increase the plant uptime to 95%.

In cement plants, the chart above shows the most critical machines.

In todays competitive scenario it is imperative to monitor these machines to increase the efficiency and therefore reliability of the plant.

This vibration monitoring solution is cost effective as a maintenance tool and ensures the total availability of plant.

Condition characteristics of the machine such as bearing damage, imbalance, alignment or cavitation enable a differentiated evaluation of mechanical stress. This will indicate when to have the shut down and the process can be ongoing without any manual interruption. Hence the equipment will be protected from expensive consequential costs.

For taking the machines for maintenance, we need to know the state of health of the machine without dismantling it. This is possible only by online monitoring. Implementing predictive maintenance leads to a substantial increase in productivity by to up to (35%).

Typical applications where condition monitoring is applicable are kiln drives, separators, crushers, screens, gear boxes, conveyor belts, fans, raw mills, ball mills, elevators and blowers.

FM Shinkawa product range includes portable instruments, online systems and accessories of rotating machinery and vibration monitoring equipment for detecting misalignment, gear problems, balancing problems etc.

The above figure shows a typical example of Fan-Motor, Crusher motor application.

Ideally acceleormeter sensors are mounted on DE & NDE bearings of machine casing in X-Y directions with the help of a mounting pad. 10meter extension cable with SS conduit is used to connect sensor and VibTrans Monitor. Accelerometer gives milli volt output which is connected to VibTrans Monitor. Further 4-20mA output is available through VibTrans monitor which can directly be taken to PLC/DCS system.

VibTrans is a dual channel monitor which gives 4-20mA output, relay output, raw buffer output.

Typical schematic Option 1: Field mount transmitter

The motor has 2 bearings and the fan has 2 bearings ( DE & NDE )

Every bearing needs to have 02 sensors (accelerometer / velocity)

FM-VibTrans Field mount Housed in IP-65 Junction box

Accelerometers

4-20mA Output

Relay Output

Buffer Output on rear terminals

Isolated Output / Modbus output-Optional - if required

FanMotor

Philosophy of Condition Monitoring and Forbes Marshall Shinkawa solutions for cement plants

MachinesMotor, crusher motor, mill motor, etc

Vent fan, separator fan, cooler ESP fan, ID fan, PH fan, etc

Kiln, vertical raw mill, ball mill, etc

Option 1: (FM-ACCL-100/CB101)

Option 2: Loop power sensor with display (FM-LPS-420/CBT420)

Accelerometer sensor with VibTrans monitor

Suitable products

Junction Box

4-20mA outputdirectly from sensors

Optionally display Indicator (DVI) can be connected for relayoutput

Rotor with

Hammer

Motor

Typical schematic Option 2: Loop powered sensors

Optionally, Loop powered velocity sensors are used for bearing housing vibrations. From these sensors, 4-20mA output is directly connected to the DCS system. These are internally Amplified Accelerometer Loop powered sensors give a 4-20mA output and hence a signal conditioner is not required.

Forbes Marshall Shinkawa products and solutions for cement plants

Accelerometers / Velocity sensors/ Loop Powered Transmitters

Multi-purpose accelerometers. Available in both top and side connectors, or with top and side exit integral cables.

Piezo velocity transducers. Available in both top and side connector versions.

Loop power, velocity 4-20 mA output sensors. Available in both top and side connectors, or with top and side exit integral cables.

Forbes Marshall-VibTrans Single/Dual Channel Transmitters

VibTrans is a simple, cost effective solution to protect machines by giving on line information which can be connected to the PLC or DCS of a plant and have a shut down whenever required through proper planning.

Modules for a wide range of inputs accelerometers, velocity sensors

Communicates overall values to PLC /DCS via 4-20mA output, relay output, buffered output, Isolated output, Modbus output optional

Simple, cost effective solution for bearing housing/casing vibration monitoring for power, steel, cement, oil & gas(safe area), fertilizer and process plants on-pump, fan, motor, gear box, crusher, blower, mounting options - field mount / panel mount available

Portable analysers

Vib Pax and Vib Soft portable Vibration analyser data collector and predictive maintenance and vibration analysis software

Two channel vibration analyser, collector, balancer, recorder, and software

VibPax

Vib Pax is a high performance tool to collect data associated with Predictive Maintenance software,

To accurately meet your requirements

at the most competitive price

With its integrated sensors (laser-sighting pyrometer and tachometer, automatic identification of the measurement point), only one cable (that of the vibration transducer) is required to identify the measurement point and measure data that are characteristic of the operating state of your machines (vibration, rotation speed, temperature).

Vibration Consultancy Services Agreement (VCSA)

(Proactive care for critical rotating machines)

Imagine if you could monitor the health problems of Critical Rotating Machines even before the symptoms become evident.

A FM specialist will be promptly available at your doorstep to address the problem.

The Consultancy Services Agreement (CSA) is a suite of proactive asset care services tailored to your individual needs and designed to help you harness the full potential of the installed condition monitoring systems.

Key Features

Real solutions with real profits

A Consultancy Service Agreement (CSA) from Forbes Marshall is a customized asset care service program designed to maximise the value of your investment in asset condition monitoring technology. We will help ensure that your system is properly maintained and is used to its full potential. Your service agreement is designed to deliver:

Proactive problem management Focus efforts where needed.

Actionable Information ensuring the right people have the right information in time to make the right decisions.

Speed of response and resolution - value realized.

Continuous Improvement solving new problems, achieving new objectives.

Specialists available on call

When there is a problem, we can perform diagnostics and give you advice on the cause and how to fix it. We can provide this service, quarterly, monthly or on demand.

Personalized solutions for individual needs

With a complete knowhow of on line vibration monitoring systems and machine details, we have developed VIBRATION CONSULTANCY (Vib Con), a unique service for customers in all types of industries. Through this service, we offer our clients remote vibration analysis and give reports for each and every critical rotating machine in the plant, by either remote monitoring of critical machines 24 X 7 and/ or periodic measurements by visits to the plant for other critical machines such as large Pumps, ID/FD/PA fans, centrifuges, large blowers, gear boxes, motors, crushers, compressors and other rotating machines.

Prod. Stop Prod.

Unexpected failure

Prod

uctio

n

time

Scheduled shutdown

Prod

uctio

n

timeStop Prod.

VibSoft

Nowadays, communication is of the utmost importance, to share and analyse results with other departments within the company, thus adding value to everyone's tasks. In addition to the Web mode, the Vib-Soft includes many features designed to help the user to exchange information: SQL-standard Oracle database, data importation and exportation, report editing and publishing (PDF, RTF, etc, formats). As for group work, Vib-Soft relies on a multi-user concept that allows different users to work on the same data set, each user keeping his/her own preferences (language, display, units, etc) independent of the others'.

Implementing predictive maintenance leads to a substantial increase in productivity (upto 35%), on the one hand preventing unpredicted shutdowns, while on the other, anticipating corrective operations so that they can be carried out under the best conditions.

www.forbesmarshall.com

Forbes Marshall Pvt. Ltd.A-34/35, MIDC, Industrial Estate, H Block, Pimpri, Pune - 411 018. India.Tel.: 91(0)20 - 27442020Fax: 91(0)20 - 27442040 E-mail: mvyas@forbesmarshall.com

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Survey of rotating machines in your plants.

Possible suggestions for Vibration Monitoring requirements.

Vibration Consultancy support for giving reports monthly / quarterly for critical machines and secondary critical machines.

Right proposal to optimize the on line monitoring cost.

Complete turnkey execution, engineering and documentation.

Vibration Analysis and diagnosis reporting for the right time shut down to save cost.

Customized condition monitoring and reporting plan for your plant.

Expert solution

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