A highly complex solution installed in Canada by BEUMER

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Dwindling resources and the resulting spike in the price of raw materials are lending ever more weight to the call for the use of alternative sources of energy. Global competition and higher production costs mean that the energy intensive cement industry in particular needs effective solutions for reducing the cost of energy. In this situation, the use of alternative fuels for energy production is gaining increasing commercial significance. Since the early 1980s, the BEUMER group has been acting as a partner for the cement industry in the development of technologies for producing energy through the use of alternative fuels. The globally operating company has set new standards with its innovative installations, in particular for the sensible use of used tires as an alternative, high-energy fuel.

The advantages of using used tires over traditional types of fuel are obvious: tires offer high heating value, which is comparable to coal or oil. At the same time, the cement industry in particular benefits from the opportunity to use the scrap iron content of the tire carcasses as mineral additions in their products. This removes some or even all of the need for adding other ferrous correctives. Other studies, including research by the Federal Environmental Agency, have proven that the use of substitute fuels is a positive development, in particular with a view on protecting the climate.
With over 50 solutions for transporting and metering used tires and tire shreds already installed worldwide, the BEUMER Group can look back on 30 years of experience with the technology. With this know-how, the company is constantly improving the operating reliability and efficiency of the technology as well as its ability to meet the increasingly tough requirements for environmental protection, emission limits and other country-specific standards. In the course of its research work, the company has also developed systems for conveying and metering ground tires (tire shreds) for feeding rotary kilns.
Pre-ground tires offer the advantage of easier batching compared to whole tires. The higher density of the material and the consequent savings in its transportation are a further argument for the choice of ground tires as fuel.

Turning tires into fuel:

One option for using BEUMER systems for the use of tires as fuel in the cement industry could be the following (cf. illustration): The tires are delivered by lorry and stored in a whole tire bunker of sufficient size to cover any potential supply issues with a few days’ reserves. A polygon crane feeds these tires into a shredder that cuts them to a desired size, before removing the discharge box that captures the tire shreds. This box can also be used as a feeder for tire shreds if the operator of the plant receives pre-cut tires shreds in place of whole tires. An intermediate storage unit for the shredded material offers enough buffer space if fuel supply has to be halted for a period of time.
The batching unit is kept in constant supply from this storage buffer, where a stable flow of fuel can be adjusted to the amount of fuel required within the defined limits. A conveyor belt transports the exactly batched amounts of fuel to the heat exchanger for feeding into the kiln through a triple-gate valve. The fuel fed into the kiln has a considerable impact on the combustion process and needs to be measured out exactly.

A lack of precision at this stage can lead to varying levels of quality in the end product. The metering procedure developed by BEUMER meets the needs of the end user in every aspect.
The great number of renowned reference clients from the cement industry is proof of the innovative technology and the thorough know-how offered by BEUMER. The specialist for intralogistics has already supplied many conveying installations for alternative fuels, including solutions for the Heidelberger Cement-Group and Cemex.

BEUMER know-how reducing costs:

Cost reductions of up to 60 percent are being enjoyed by the internationally active cement producer Ciment Quebec Inc., based in St. Basile, Quebec, Canada. Since early 2006, the company has been using a highly complex BEUMER solution for shredding, metering and conveying tires as fuel in the production of cement. When the contract was awarded in June 2004, the client expected BEUMER to install a system that supplies its kilns with alternative fuels. These were supposed to include whole and ground tires as well as other automotive scrap, shredded plastics and wood.
The finished installation has delivered all the elements that ensure the reliable and constant supply of alternative fuels for the production of cement.

Processing methodThe delivered shredded tires are dumped and stored in a storage bunker, from which a belt conveyor removes the required amounts of fuel. Ultrasonic sensors monitor the required levels.
Counter-rotating scraper roles produce an even distribution of the tire shreds. The flow of material is batched gravimetrically by means of a single-roller belt weigher coupled with the speed control of the conveyor system. The even discharge of the material into the kilns is managed by a winch roller, which stops oversized or stuck batches from entering the kiln.

Automatic sorting
For the burning of whole tires, a conveyor system was designed that uses special sensors to identify and exclude strongly deformed tires or wheel rims. Material that is unusable for burning is automatically conveyed to a discharge point.

A bespoke belt system then transports the fuel to the oven. In order to avoid leak air entering the kiln during the feeding process, the kiln gate has been designed as a triple rotary gas lock. Three consecutive gas locks made from special steels allow only minimal heat loss as a result of their material and special design. This maintains a highly leak-tight system.

Release link: http://www.beumer.com/htcms/en/news/mehr-3.html