Kiln maintenance: Prolong the lifespan of your plant

October 26, 2017 Jacob Jørgensen

At the heart of the cement plant, the kiln plays a vital role in production and its maintenance is crucial to ensure a healthy output. With savings in costs and performance guarantees, maintaining the kiln is a sure-fire way of delivering productivity improvements.

Kiln failure typically stems from four root causes: axis misalignment or misbalance, shell ovality, shell flex or crank failure. These can lead to critical issues such as hot bearings, longitudinal and circumferential kiln cracks, excessive wear of kiln tyres and rollers, wear between kiln shell and tyres and lining failure.

Such issues can cause unplanned shutdowns and expensive downtime – preventing them is an essential part of a plant's maintenance strategy.

Investing in quality maintenance
In addition to the peace of mind in knowing the kiln will operate smoothly, there are compelling economic reasons for a solid maintenance strategy. Analyses show that planned maintenance costs approximately half that of reactive maintenance, while preventive maintenance costs about two thirds of planned maintenance.

Two key maintenance procedures required at regular intervals throughout a kiln’s lifetime are hot kiln inspections to analyse the kiln’s performance (see table) and resurfacing of tyres and rollers.

Kiln service agreement modules

The resurfacing work can cause the kiln equipment to change its behaviour resulting in, for example, different thrust characteristics of the support rollers. This behaviour is monitored continuously during the process and necessary adjustments are made to the equipment by the engineer. When the process is completed, the support rollers are adjusted correctly for thrust, minimising the risk of future problems.

Resurfacing of rollers and tyres
Resurfacing can improve the mechanical efficiency of the kiln and is performed while it is in normal operation – meaning no costly shutdown period. The need for resurfacing develops from various types of wear and tear issues. Left unaddressed, these conditions can lead to increased power consumption, alignment problems and reduced bearing life.

Why resurface?

  • Improves mechanical stability
  • Reduces energy consumption (by up to 40%)
  • Lowers operating costs
  • Avoids issues such as premature bearing failure and damage to tyre retaining components, bases, and drive components.

Qualified, experienced specialists applying the latest tools and techniques helps reduce operating costs

A kiln health check
The engineering study is one of the most valued outcomes of a kiln maintenance inspection as it provides a behind-the-scenes look at the kiln's health, based on its actual use. The valuable report can be used to maximise productivity in the plant, but the complex calculations used to generate the readings often means a need for onsite kiln maintenance training, which includes explaining the calculations.

The study provides a report encompassing insight into possible overloads and excessive stress levels, along with structural information that is critical for correct alignment. Information about bearing load, bending stresses in the tyres and kiln shell, and contact pressure between supporting rollers and tyres is included. It also addresses spare parts replacement and makes recommendations for spare parts inventory management.

Experts in maintenance
Selecting the right service partner is essential in ensuring the healthy lifespan of a cement plant. FLSmidth’s maintenance specialists perform over 200 alignments and resurfacing projects annually. Its ample expertise stems from experience in process design and equipment manufacturing.

Many of the kiln specialists themselves have worked in the cement industry for decades. As engineers by trade and education, they have extensive knowledge and training in kiln maintenance.

FLSmidth offer stand-alone kiln service contracts as well as comprehensive preventive maintenance programs, enabling plant operators to tailor their servicing needs according to their budget and productivity targets. Additionally, FLSmidth’s maintenance services are not limited to its own equipment and can even supply spare parts for any kiln in operation.

Servicing the world
Recognising the need for high-quality, fast and cost-effective services in sometimes remote locations, many of FLSmidth’s kiln service specialists are based close to many major cement plant operations around the world. And thanks to this global set up, most plant owners can be assured that the heart of their production line is well maintained.

A network of global service centres brings FLSmidth’s specialist equipment and expertise to the cement plant’s doorstep

Planning for the future
Preventive kiln maintenance is a way of ensuring the future of the cement plant. In turn, plant owners can be assured that productivity is optimised according to plant capability, that costs of operation and maintenance are minimised and the risk of sudden plant shutdown can be avoided. It is a small price to pay for a healthy kiln.

Case study
Asia Cement’s Russia-based plant significantly improved its operating costs following a hot kiln alignment, conducted by FLSmidth. The plant’s production line is not comprised of FLSmidth equipment, but maintenance specialists demonstrated their expertise with kilns by successfully performing the alignment. The plant’s technical director reports that the kiln drive power consumption has reduced by 94.5 kWt/h.

Jacob Jørgensen


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