Considerable attention is being paid to automation as a built-in facility at the planning stage of a cement plant. But the wonderful part is even retrofitting the automation systems in the existing plants is not too difficult. Many multinational companies like ABB, Siemens, Yokogawa, Honeywell, and Rockwell are offering services to Indian cement industry. We have moved away from centralised system to DC System (DCS).
DCS as it is commonly known, is a type of automated control system that is distributed throughout a machine to provide instructions to different parts of the machine. Instead of having a centrally located device controlling all machines, each section of a machine has its own computer that controls the operation. For instance, there may be one machine with a section that controls dry elements like powder formation and another section controlling the liquid elements, but each section is individually managed by a DCS. A DCS is commonly used in manufacturing equipment and utilises input and output protocols to control the machine.
Archana Gupta, Manager - Electrical, Penta India Cement & Minerals, on the subject elaborates, "In today´s scenario, automation plays a vital role for process control. Clinker making is the most complex process, which involves a lot of uncertainties. Hence to ensure a smooth process, control automation and optimisation of the circuit is a must and mandatory. Also, high energy consumption is observed during the clinker making process and in order to ensure energy-efficient operation, optimisation plays a vital role. Advanced process Control (APC) has much to do in this area for a smooth process and to maintain uniform temperatures in the respective zones to achieve consistent clinker quality with less human errors."
Automatic Robo-Lab system is used for maintaining the quality of product with proper raw material mixing and proportion modelling. By the automatic Robo-lab technology, key activities such as sampling, sample preparation and analysis are automated to provide fast, reliable and consistent information for quality assurance and process quality control.
However, there is a common perception that when labour is so cheap in India, why to invest in robotic labs. At the same time, there is no guarantee that the sample collection is done without errors in the right way given the adverse seasonal climatic conditions, intricate sample points and odd working hours.
Gupta observes, "Samples can be collected manually at various points. But advantages of doing it online can avoid manual errors and prevent the sample from moisture. It also helps in timely collection and analysis of samples."
With Robo-Labs we can control the material feed at various levels. Today Robo-Labs have been installed in various cement plants of Dalmia, Reliance, Wonder Cement etc. Robo plays a vital role in positioning the samples on time on analytical instruments. Tracking of quality at each point of the material and controlling the material flow properly will lead to reduction in energy consumption, increase in productivity, and improvement of production costs.
There have been many levels of automation. Depending on the size of the plant and requirements of the clients, automation companies can customise their product offerings. One such advancement is Expert Optimiser, commonly known as EO. This is a computer-based system for controlling, stabilising and optimising process in cement manufacture. It is supported by a software that helps one to make the best operational decisions accurately and consistently at all times. EO provides advanced process techniques, predictive control, fuzzy logic and neural networks.
EO supports the plant personnel to reach different stages of process through pre-decided set points by using computer programs. Any deviations are noticed immediately and alarms are generated. One can reach the operational targets easily. Today, there are EOs available for kiln optimisation, alternative fuel management, mill optimisation and material blending.
For smooth clinker production, exact raw meal composition is necessary. EO available today can offer assistance for raw meal proportioning as well as for finished grinding.
In short, EO has many applications and one will have to be selective to choose the right one.
For successful implementation of EO, it is important that correct and authenticated data is shared with the supplier. Incorrect and insufficient data may not give the desired results. The full involvement and dedication of the staff is next important stop in EO though long term support is available from various EO providers. Gupta points out, "EO for kiln and cooler will help the process run in smooth manner.
Both kiln control system (KCS for kiln and cooler) and mill control system (MCS) use actual plant data to make precise predictions about quality parameters, and they can be integrated into an existing automation control system with no additional hardware. The MCS and KCS systems sit on top of the basic automation level and give set points to the already commissioned and fine-tuned PID controllers in the basic automation. Plant process parameters that the operator enters manually result in consistent operation throughout the day. Furthermore, set points can be issued to the already commissioned and fine-tuned PID controllers in the basic automation. This ensures that the kiln and mill are pushed to its maximum performance and the operators are freed up of their routine monotonous work."
Cost factor is one of the concerns according to Gupta. Moreover, selection of OEMs with good technology and domain expertise is a challenge. Going for different systems for different process, segregated data from various controllers etc, it is preferred to have common system for the entire process.