CASE STUDY : LAFARGE Langkawi Plant, Malaysia (CS4)

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About LAFARGE Malayan Cement

Lafarge Malayan Cement is a manufacturer of building products. The company is organized into two business units: cement and aggregates and concrete.

The company’s cement operations are located in Malaysia and Singapore. In Malaysia, it operates a nationwide network of facilities which include three integrated cement plants in Langkawi, Kanthan, and Rawang, one grinding plant in Pasir Gudang, and distribution channels by road, rail, and sea. In Singapore, the company’s Lafarge Cement Singapore (LCS) subsidiary produces and markets various types of cement including oilwell cement, which is exported to East Asian countries, and a range of dry-mix cement products.

Aggregates and concrete activities take place in Malaysia, Singapore, and Vietnam. In all three countries, the company operates through Supermix, a provider of ready-mixed concrete.

The Situation

In September 2006, the cement plant located in Langkawi conducted its routine annual shutdown for maintenance.

Among the plant’s facilities stood a 16,000 ton capacity, multi-flow cement silo which had been on the management’s agenda months before.

Cement Silo 4 (CS4) which contains 98% full of top grade cement meant for export has not been in operation for 2 years. Located in the central chamber of the silo are sixteen blocked inlets that prevented the cement from flowing into the discharge gates.

The Decision

Having deliberated over the impending problem for some time, the management realized that it would be difficult for them to remove the blockage themselves. It was decided that the task should be outsource to a silo clearing vendor who had the capability and experience to undertake this project. Silo clearing is never an uncommon issue, especially for a multinational and established organization such as Lafarge. In a country like Malaysia, this task has been undertaken by both local and European contractors in the past. Previous silo clearing projects however, were very much straightforward. Normally the silos would be emptied to 0% capacity. These contractors would then perform the clearing process, often using bulky equipment and lengthy durations. In this situation, it was impossible to discharge the contents of CS4 as all sixteen inlet chambers were blocked with hardened cement. This prevented the contents from flowing into any of the two the discharge gates. As CS4 was also 98% filled to capacity, safety was an utmost concern for those involved with the project. Traditional contractors with their conventional silo clearing methods posed as a safety threat to both equipment and manpower. Given the circumstances, contractors would often use the opportunity to quote exorbitant prices for undertaking the project – Unless of course, you engage someone who is both equipped and trained to use the Cardox System.

The Solution

The Cardox CO2 System is recognized as the most EFFICIENT, RELIABLE  and COST EFFECTIVE method of clearing build up and blockages in Preheaters, Cyclones, Inlet Chambers, Riser Ducts, Feed Pipes, Rotary Kilns, Raw Feed Mills, Precalciners, Coolers, Silos and anywhere in the Plant Processing Line. Cardox involves carbon dioxide gas, an inert gas commonly used in fire extinguishers, creating a powerful heaving force which breaks the surrounding material with no shock waves or damaging vibrations.

The capabilities of the Cardox CO2 System perform beyond those provided by competing silo cleaning methods. Besides being able to handle extensive silo build-up and blockages with ease and flexibility, it is also versatile enough to use Cardox where other methods are impossible and / or unsafe to employ. Cardox’s silo cleaning services offered Lafarge an inexpensive, safe and uncompromising solution to resolve the problem in CS4.

The Cardox silo cleaning team adopts a systematic approach to the problem:

• To study and understand the technical data / drawings of CS4
• To conduct joint discussions as well as on-site visits with the silo engineers
• To determine and propose the safety requirement , handling and execution of the task
• To manage the schedule and sequence of work to be performed
• To constantly maintain communication and status update to the client
• To provide a daily job log of work performed that is endorsed by the client

Once items 1 – 3 had been accomplished, the equipment was packed and shipped to the plant.

The Cardox silo cleaning team comprising of 2 engineers later arrived in Langkawi to coordinate the unpacking, assembling of the Cardox recharging unit and preparation for the work to be carried out.

Close inspection of the inlet chambers revealed the hardened cement that had been causing the problem. The blockage had affected all sixteen inlet chambers, making it impossible for any material to flow freely into the discharge gate. It was apparent that all sixteen inlet chambers had to be cleared to enable the cement in the silo to flow into the discharge gate.
Holes are made in each of the sixteen inlet chamber so that the CARDOX tube may be inserted and activated within the problem area. The Cardox tube is inserted into the hole made in the inlet chamber. For safety reasons, a maximum of two tubes are activated simultaneously so that at each time, two inlet chambers are cleared.

The Cardox tube is activated safely from outside the silo via a wire connection to an electrical igniter. The manhole access is then closed shut during the activation.

This method ensures that the silo clearing operation is completely safe and smooth all of the time.

As a safety measure, inlet chambers are cleared at alternating chambers. The central chamber and existing inlet chambers are closely watched and constantly inspected before and after each clearing exercise for signs of potential danger. Eventually all sixteen inlet chambers are cleared from any blockage. Cement from inside the silo containment area can be seen flowing through the inlet chambers.

After a final inspection is done by the client, all the equipment is removed from the work area.

Finally, the manhole access is sealed and CS4 is ready to be started up again.

Preliminary report following the start-up of the silo showed that hot cement has flowed through the inlet chambers into the discharge gates. Further follow-up with the client confirms that the blockage has been completely cleared from the inlet chambers. The blockage clearing project had been successful.