Traditional laboratory processes have given way to robotics for ensuring quality control and avoiding health hazards in 24x7x365 operation of cement plants.
Quality control equipment of cement industry, which was automated over the years, is turning towards robotics, of late. In the early days, sample collection and transfer it to testing laboratory and adjusting the controls based on the laboratory results were being done manually. Then came semi-automatic sampling and automatic sample preparation; followed by automation of sample transportation; then a compact and interlaced design that suits a single integrated line or a clinker grinding facility was introduced, and now, robots have entered the arena. Today, human intervention in the process has been reduced to almost nil by robots.
Increasing environmental regulations, need for production efficiency and cost control at every level, need to curtail human errors in this continuous process industry, and growing demand for consistency of product quality by customers are placing increasingly tough requirements for sample analysis quality and complexity, and for sample throughput in cement plants. Besides, availability of skilled manpower in remote areas where many cement plants are located, and retaining them has become a difficult task for companies. So, remote operation, support from distant locations, and online assistance are all vital for the smooth operation of quality control systems in modern cement plants.
Indian cement industry is known to be one of the leaders in emission control in the world is also emulating global best practices in quality control, which strive to ensure:
- High speed and accuracy of sample collection and results;
- Stricter quality controls sought by cement markets;
- Support for 24x7x365 operations; and
- Zero health and safety hazards or incidents.
Robotics
The traditional process of cement sampling involved use of motorised or hand operated to collect material from the process, which used to be carried to the lab by a boy and the lab operator used a manual pulverising mill to grind it in a tungsten carbide or steel bowl to a fine powder, before using it for testing.
Most of the companies deployed manpower for collection and preparation of sample, which created manual lapses and error in sample itself, which ultimately affecting quality of product and its control actions. So, most of the companies are adopting lab automation and robotics for utmost accurate sampling analysis for their latest plants.
Suppliers today offer a range of fully automatic solutions from robot-free to multi-robot systems and also in phased manner to spread the investment over a few years. "The latest offering is use of robots or collaborative robots in laboratory automation, allowing a common shared space for both humans and machines as well as give a lot of flexibility to support future growth," says Jagdish Chandra Toshniwal, Managing Director, Wonder Cement Ltd, which is in the process of setting up the latest laboratory automation equipment in their factory.
This technology has matured over the years. The lab automation suppliers are moving their data over to cloud and perform analytics on the quality data by relating it to process data and this can be opened up for end-users of the product. And it can also be accessed on a mobile phone.
Companies like Emami Cement collect the sample through auto samplers controlled by robotic operations which are programmed in robo PC. "This ensures timely sample collection with utmost safety and without any human intervention. The other features include, auto sampling; auto sample preparation and analysis; provides safe, fast and reliable information; integrates all cement quality-control activities in a single system; and incorporates in-depth understanding of the production process," says Vivek Chawla, Whole-time Director & CEO, Emami Cement Limited.
The latest offering by lab automation suppliers to control entire quality from mining to cement production include pile analysis and control, Blend Ratio analysis and control software, automatic free lime calculation, Blaine analyser, automatic carbon sulphur analysers etc.
All material in a process flow must have an equal probability of being sampled. There are no methods of analysis that can compensate for errors/bias in the sampling stages. Therefore, it is crucial that the company always asks itself if the sampling method is adequate when investing in sophisticated analysis technology, says S Sankaralingam, QCX Sales, FLSmidth, which is one of the leading supplier of laboratory equipment for cement plants.
Integration of various systems in the process of manufacturing is the basic necessity for any lab automation equipment for reaping full benefits. "The integration between laboratory and power control enabled us to get uniform quality of raw mix, which in turn helps us to get stable running of kiln and cement mills with consistent quality," says Chawla. The lab automation system is integrated with various automation systems like cross belt analyser (CBA), Plant Central Control DCS system for Ratio Control of Raw Mix feed at Emami Cement.
Latest technologies ensure that chemistry of raw materials is constantly and automatically monitored without any human intervention. "The integration between the laboratory and power control is flawless which allows us to control the quality of raw mix, clinker as well as particle size distribution of cement products. Under this operation, change in desired mix, prompts the advanced quality control software POLAB? AQCnet software to re-calculate the raw mix finally through AQC net," says Toshniwal.
By monitoring quality of final products as well as intermediate raw meal or kiln feed, the manufacturer can stabilise the process leading to better productivity and to be more specific, capability of bringing down standard deviation of this system, leading to better throughput and production of consistent quality product.Installation
The cycle time for such installations typically takes about eight months depending on plant readiness and infrastructure availability. For a greenfield cement plant, however, this can be done in parallel to the main plant and machinery ordering, which anyway has a timeframe of 12-18 months of concept-to-market.
For Wonder Cement, which is installing the lab equipment at its plants, the cost incurred is approximately Rs 200 million, including one CBA and two XRF for managing two lines of operation. "Depending on plant size the cost could be anywhere in the range of Rs 80-120 million, with analysers costing another Rs 30-40 million," says Toshniwal.
Responding to a query on return on investment (RoI), Toshniwal added, "Approximately three years," considering indirect benefits from increased productivity and efficiency, better lining life of kiln, optimised use of additives, reduced kiln stoppages, reduced clinker factor. Over and above, production of quality products consistently, reflects in better image in the market which gives leverage for enhancing sales, he feels.