Cementing the Process

Holcim is one of the most established names in the perhaps not glamorous but certainly very important world of cement – that basic building block of the construction industry. Starting operations almost a century ago in 1912, the Swiss company has grown into a truly global company and now employs 80,000 people across all the major regions of the world.

Notably, and no doubt with an eye on riding the construction activity that naturally goes along with economic growth, Holcim has built a significant presence in emerging markets around the world. In FY2009, for instance, almost 30 percent of the 21 billion Swiss francs (US$19.7 billon) revenue was contributed by the Asia Pacific region.

And in its latest annual report, released in March, the company notes that, “Population growth, major infrastructure needs and increasing urbanization will remain key growth drivers in Asia Pacific. In a majority of markets served by Holcim, further strong demand for building materials can therefore be expected.”

It is not surprising then that Indonesia is one such market, given its huge population (over 200 million) and consistent economic growth rates – in the five to six percent range for most of the last few years.

On the main island of Java, Holcim Indonesia operates three production facilities: two fully integrated cement plants in Naragong, West Java, and Cilicap, Central Java; and a cement mill in Ciwandan on the north-west tip of West Java.

All in the mix

“This is a grinding and packing plant,” explains Bambang Soekarno, plant manager at Ciwandan. “The clinker (the intermediate product in the cement-making process) is transported here from the Narogong plant, stored in the silos, and then ground with the gypsum and additives in the mill to produce cement.”

The output from the grinding mill, which employs some 100 permanent and contract staff, is then packed into the familiar brown cement bags for distribution out to Holcim Indonesia’s customers, the majority of whom are located in West Java and across the water on the neighboring island of Sumatra.

After purchasing the plant from previous owner Cemex, the Mexican cement manufacturer, the facility was modernized and re-equipped. A key part of the upgrading was the selection and installation of a control system, and for that, Soekarno and his team turned to Siemens and its PCS 7 process automation system. For cement producers, the value of PCS 7 lies in Cemat, a version of the control system that is specifically designed to meet their needs.

With Cemat, cement plant producers can focus on optimizing the process rather than designing the basics of the control system, says Siemens. For instance, preengineered software modules and operator interfaces help shorten time to market, reduce costs and increase plant output.

System scope

At Ciwandan, the Siemens control system operates in three main parts of the facility: Cement Reception – where the trucks carrying from Narogong are unloaded and their clinker cargo stored in the two huge silos; the Grinding Mill – the core part of the plant where the massive cylindrical grinder is sited; and the Packing Section – the area where hoppers, packing machines, and belt conveyors form the final part of the process.

Two Siemens S7-416 PLCs – one for the Grinding Mill and one for Receiving and Packing – form the heart of the control system. These connect via Profibus DP network to ET 200M remote I/O modules (a total of 20) that interface to the actual plant equipment under control. The range of instrumentation includes radar level devices for the silos, as well as temperature, flow, and pressure devices elsewhere in the plant.

Up to the control room, the PLCs connect via fiber optic Ethernet and Scalance X switches to two Cemat Operator Stations (OS), which enable monitoring and control via the HMI screens, and one Cemat Engineering Station (ES). An additional PC is used for long-term data storage.

According to plant manager Soekarno, one week’s PCS 7 training was provided by Siemens for 15 operators, and the automation supplier now provides online engineering support which is “quite good”.

He also professes to be “very pleased” with the system that forms a critical part of the cement manufacturing operation, which in turn is an important part of Holcim’s growing presence in Indonesia and Holcim Indonesia’s vision “to grow and be the best performing and most respected Indonesian company in our industry, ranked amongst the best in the Holcim Group”.