AAC project in southern Brazil also successful with
remote processing - an intermediate report

The company Celulcon is a renowned producer of autoclaved-aerated concrete (AAC) in southern Brazil. Its market share is rising continuously, resulting in the need to utilize all optimization potentials in order to increase performance.

The managing directors of Celucon and KB Engineering, Antonio Zanon and Norbert Ferdinand Kajüter, have known each other for nearly ten years – a relationship that developed through continuous contact and regular exchange of experience. Apart from information about new products and developments in plant engineering, they also discussed options on their utilization on the Brazilian market. In this context, they examined the expansion of Celucon’s potentials. KB Engineering’s international experience in developing innovative plant concepts and their implementation made it possible, here in Brazil as well, to take new paths in order to extend the product portfolio and to be able to serve new market segments. In addition to conceptual development of individual machine lines (e.g., unloading systems with automatic visual quality inspection and sorting), all the way to turnkey plants in the AAC industry as well as for other construction materials, KB Engineering is likewise active in development of insulation-foam production lines (e.g., manufacture of granules from desert sand). These insulating boards are based on non-combustible cementitious foams that are installed both for increasing the Lamda ratings in perforated masonry blocks (concrete blocks or clay), or are manufactured as sheet products (gross density between 75 to 300 kg/m³).

Dr. Lutter, of IN-projects GmbH, draws on more than 30 years of international experience in production of autoclaved-aerated concrete as well as of insulating boards with low gross densities. Its activities focus, among others, on international troubleshooting, providing support in the development of production sites through to commissioning. Special attention is given to the interaction of raw materials with the various process-engineering steps. Often, quite amazing savings both in raw materials and energy are realized by merging data from the process and from the laboratory, as well as by their balancing.

As the result of the collaboration of KB Engineering and IN-projects, it was possible to input technical competence and experience potential over an entire product line, in this as well as in other projects. The engineering and optimization activities provided by the two project partners in this and other plants are not related to specific types of plant, but are adapted individually to local conditions.

With a view to product and capacity extension, optimization of formulas and the mixing processes, as well as of the process steps, became necessary and extended to an increase in production output and, at the same time, to reduction in production costs.

On-schedule implementation notwithstanding the Corona restrictions

The start of the project, on location, had been planned for May 2020, but had to be repeatedly postponed owing Fto the Corona restrictions imposed worldwide. Due to the high improvement potential to be expected, the project partners at long last concluded not to wait for the end of the travel restrictions (the date of which was uncertain), but to implement the project steps via video conference. Another aspect that had to be considered for video conferences was the time difference of five hours. An additional challenge was the desired improvement of plant output by around 6 %, by utilizing the existing machine engineering and without installing additional system components.

Under normal circumstances, plant inspections and detailed observations at specific nodal points are customary in order to pinpoint aspects in need of improvement, weaknesses and error sources, in particular in the production process or in process engineering – which, due to the travel restrictions, were not possible. It was accordingly necessary to collect data on all raw materials, operational sequences and environmental parameters, on the basis of photos, videos, drawings, workflow descriptions and handwritten notes, and to transmit them by email. Since this information was partly available only in the national language, Portuguese, it was also necessary to bridge this language barrier, which in the beginning inevitably resulted in misinterpretations and mix-up of terms.

After overcoming some initial difficulties – due to Internet performance problems – it was rather quickly and effectively possible to identify the first steps to be taken regarding the quality of the raw materials. The required limestone, for example, was unfortunately not available on the free market in the required quality and quantities and had to be especially manufactured for Celucon in a large charge and placed in interim storage over a long period of time. This resulted in a storage problem, because long storage times frequently lead to undesirable moisture absorption, resulting in a change of reactivity. Fluctuations in the consistency of the raw materials made it more difficult to carry out the continuously required adjustment to the formulas, dealing with which, moreover, requires a great deal of experience potential on the part of the operator of the mixing plant. On the basis of the raw materials, it was possible to improve systematic mixing processes, the rising and curing behavior of the cakes, curing times as well as autoclaving and steam generation.

KB Engineering, in collaboration with IN-projects, was able to incorporate the experience required for this challenging project, as well as to employ the readiness to take new approaches requisite for achieving the desired improvement of the processes. All participants in the project knew that implementation without support of the activities on location would most likely lead to a longer implementation time, since the necessary assembly compilation of the results obtained, and continuous optimization – in consideration of the different time zones – would leave only a narrow time window for the daily video conferences. With intensive online support for the measures to be taken in Brazil by the German partners, it was nevertheless possible to meet the targets as scheduled within around two months.

Satisfied Brazilian customer

KB Engineering and IN-projects made use of the additional improvement potential identified and already implemented during this time, and in this way were able to increase the performance of the plant beyond the expected level. This resulted in an increase of output of high-quality products by more than 8 %, and in a sustained increase of process efficiency. In addition, it was possible to achieve a reduction in the raw materials requirement (in particular for cost-intensive components such as cement and limestone), together with an increase in product quality as well as with time-optimized production steps. Thus, the reduction in variable costs for feedstock and energy savings has not yet been comprehensively calculated, but is between 4.8 and 5.2%.

Celucon Production Manager Daniel Zanon is clearly satisfied: “The special benefit for us was that no new expensive machine components or conversions of plant components were required for achieving these outstanding results – optimization was implemented during normal and ongoing production. The restrictions imposed by the pandemic had forced us to work in remote sessions. The KB team of engineers nevertheless succeeded in proposing solutions and improvements for our challenges, although we were not physically present with hands and eyes. The exchange of information in conjunction with the experience of the KB team of engineers enabled us to reduce errors and to increase productivity in a number of areas.”

Issues involving reduction of autoclaving time and saving of fresh steam were already identified as further potentials and project steps for improving plant performance – the implementation of which is in preparation.