Hot Kiln Alignment

Introduction

Industrial Supervision GmbH, utilizing expert kiln specialists with over 20 years of experience and having successfully completed dozens of hot kiln alignment projects, is fully prepared to carry out inspection and hot kiln alignment of cement and pelletizing plant with the highest level of quality and precision.

The knowledge and experience of our experts, combined with the use of the most up-to-date, advanced, and precise measuring equipment, as well as access to specialized kiln analysis software, enable us to identify potential kiln issues after conducting the necessary measurements. By performing root cause analysis and providing appropriate solutions before serious damage occurs, we can reduce unplanned kiln shutdowns and prevent costly repair expenses.

The Importance of Hot Kiln Alignment

The rotary kiln is the heart of cement and pelletizing plants and plays a vital role in production. Performing regular hot kiln alignment increases the lifespan of the equipment and offers the following benefits:

Performing a hot alignment makes it possible to restore the furnace to its optimal settings without disrupting production. The furnace hot alignment operation carried out by Industrial Supervision includes a wide range of measurements performed using various specialized and unique instruments and equipment. This ensures that all key furnace parameters are thoroughly examined and analyzed.

Our experience shows that most major failures in rotary kilns are caused by the following four factors:

By performing regular and timely comprehensive kiln inspections and hot alignment, and by identifying and eliminating the four main causes of kiln failures, the following objectives can be achieved:

Kiln Axis Measurement

One of the most critical factors in three-pier and multi-pier kilns is the proper alignment of the kiln axis in both the vertical and horizontal planes. If the kiln axis is not properly aligned, the load distribution on the rollers becomes uneven. As a result, some bearings are subjected to higher loads, leading to increased temperature and reduced bearing life.

Moreover, the additional load on the roller shafts can cause problems such as cracking or even shaft failure. Another detrimental effect of kiln misalignment is the increased stress on the kiln shell at the tire and roller contact areas, which can lead to shell cracking and abnormal wear of the tires and rollers.

Using highly precise measuring instruments, our experts accurately determine the position of the kiln axis in both horizontal and vertical planes and specify the required roller adjustments to correct the kiln alignment.

Axial Balance

The axial forces of the kiln must be properly supported by both the thrust roller and the kiln rollers. The share of each component (thrust roller and support rollers) in carrying these axial loads is clearly defined.

If, for any reason—such as incorrect roller angles—the axial balance of the kiln deviates from its normal condition, and the lift or drop of the rollers changes, excessive loads may be applied to the roller bearings and the thrust roller.

Such excessive loads can lead to severe consequences, including increased bearing temperatures, damage and failure of internal bearing components, failure of the thrust roller bearing, or even fracture of the thrust roller shaft.

By measuring the angle and slope of the rollers and examining the pressure applied to the thrust roller, our experts ensure that the axial forces are properly balanced. If any imbalance is detected, the necessary adjustments to the roller angles and slopes are determined to restore the axial balance to its optimal condition.

Crank Analysis in Rotary Kilns

In rotary kilns, a critical phenomenon known as crank may occur, which can appear as either mechanical crank or thermal crank. The crank in a kiln becomes visually noticeable only when its magnitude increases significantly and reaches a dangerous level, to the point that the kiln tire (ring) may lift off from the support rollers. Crank can cause serious consequences such as damage to the roller bearings, wear or deformation of the tire and rollers, and even fracture of the roller shaft.

The amount of crank is measured using a specialized device that evaluates the deflection of the roller shaft through a non-contact method. If the measured crank exceeds the allowable limit, the type of crank (mechanical or thermal) will be identified, and appropriate corrective actions will be taken accordingly.

Girth Gear and Pinion Inspection

Ensuring the proper alignment and settings of the kiln’s girth gear and pinion is of great importance. Our specialists use advanced non-contact equipment to measure the axial runout and radial runout of the kiln gear and determine whether the measured values are within the allowable limits. In addition, by measuring the temperature distribution on the girth gear and pinion, as well as checking the root clearance (where possible), the correct alignment and engagement of the kiln gear and pinion are verified.

Ovality and Migration Measurement

In rotary kilns where the tire (ring) and the kiln shell are in a loose condition relative to each other, understanding the degree of ovality of the kiln shell and the relative movement between the tire and shell is highly important. Ovality and migration are interrelated parameters and must remain within the permissible limits. Both excessive and insufficient values of ovality or migration can lead to undesirable consequences.

Excessive ovality can significantly reduce the service life of the refractory bricks and is one of the main causes of longitudinal cracks on the kiln shell. On the other hand, very low ovality or migration may lead to deformation (necking) of the kiln shell beneath the tire.

During the hot alignment process carried out by our experts, the ovality of the kiln is measured, and appropriate corrective actions—such as increasing or decreasing the thickness of shims under the tire pads—are recommended to restore proper operating conditions.

Engineering Calculations and Kiln Analysis Using Kiln Calculation Software

Industrial Supervision Company is capable of performing a wide range of specialized kiln engineering calculations, providing you with valuable technical insights, including:

These results offer significant assistance in optimizing the adjustment of support rollers and can also be highly beneficial during major overhauls and annual maintenance of the kiln — for example, by monitoring crack-prone sections of the shell or bearings under higher loads.

Kiln Shell Profile with 3D Animation

Monitoring the deformation of the kiln shell is highly important. When the level of deformation exceeds the allowable limit, it can adversely affect the service life of the refractory bricks. In some cases, excessive deformation may also indicate a reduction in shell thickness in that area, which could serve as a warning sign for potential crack formation.

The measurement of shell deformation across the entire length of the kiln is performed using a specialized high-precision camera. After transferring the recorded data to dedicated software, the shape and magnitude of the shell deformation are analyzed and presented in both 2D and 3D formats.

Finally, a color 3D animation is generated, allowing users to easily visualize the shape and degree of deformation along the entire kiln length at any desired location. This provides a clear and intuitive understanding of the kiln’s structural condition.

Comprehensive Visual Inspection

In addition to all the necessary measurements performed using the most advanced and precise instruments, a comprehensive visual inspection is carried out based on specific procedures and standards. This inspection covers all parts of the kiln, including the surface condition of tires and rollers, the positioning of the tire on the rollers, the condition of the kiln inlet and outlet seals, the lubrication system, the status of support pads, retainer blocks, and axial guides, as well as the nature and quality of contact between the tire and rollers, the presence of any V-Gaps, and other related observations. All findings from the inspection are documented and illustrated in the final technical report for a clear and comprehensive evaluation of the kiln’s condition.

Additional Inspections and Measurements

The comprehensive kiln inspection services provided by our company, in addition to the eight main sections described earlier, also include the following supplementary measurements and evaluations:

Post-Inspection Training Session and Preliminary Report Presentation

After completing the inspection work, Industrial Supervision experts conduct a training session for the plant personnel involved in kiln operation and maintenance, explaining the key concepts and essential practices for effective kiln upkeep. During this session, they also respond to any technical questions from the staff.