Great success with dosing technology

February 1, 2016 THOMAS JENNEWEIN

Calciner line upgrade with FLSmidth Pfister® dosing technology a great success

Arabian Cement realises big savings burning alternative fuels

Adel Ezzat, Alternative fuel Manager at Arabian Cement plant in Ramliya, Egypt

Altering existing production setups is always a special challenge for any engineer. At Arabian Cement Company in north-eastern Egypt, FLSmidth dosing specialists integrated a multifuel feeding line with rotor weighfeeder Pfister TRW/S-D as the core technology. Imported energy carriers can now be replaced at an increasing rate by low-cost locally available alternative fuels such as biomass, tire chips or sewage sludge.

Arabian Cement (ACC) is a leading cement company located in the Governorate of Suez, in north-eastern Egypt. Up to five million tonnes of high quality cement leave ACC every year to support the local market. In addition, high quality concrete products are provided by Andalus Ready Mix Concrete, an ACC subsidiary. ACC is listed on the Egyptian Stock Exchange and recently expanded operations to Brazil.

Two production lines are running at the heart of the main plant in Egypt. One of them was set up in 2011 by FLSmidth and subsequently equipped with an alternative fuel installation by FLSmidth in 2013. Replacing imported coal or gas with widely available, cheap energy carriers such as sewage sludge or plastic waste made perfect economical sense. Space limitations within the production line sent FLSmidth engineers to the think tank. Their smart solution: a balcony-type addition to the calciner tower holding a rotor weighfeeder Pfister TRW-S/D setup.

The red rotor weighfeeder Pfister TRW-S/D is designed to dose up to 12 t/h of alternative fuels at Arabian cement

“The entire system is fully automated and includes primary storage and shredder system, magnetic separation, transportation to the intermediate storage area, a discharge system from intermediate storage, a gravimetric dosing system and an injection system into the kiln precalciner,” explains Adel Ezzat, Alternative Fuel Manager at Arabian Cement. In the ACC installation in Egypt, alternative fuels can substitute up to 30 percent of conventional fuels, mainly imported coal.

“Starting with a seven percent substitution rate in 2013, ACC is already using 12 percent alternative fuels in 2015, with similar annual increases planned in the coming years" - Adel Ezzat, Alternative Fuel Manager at Arabian Cement

Rotor Weighfeeder Pfister TRW-S/D meets all requirements
Its simple, no-nonsense design with no unnecessary frills that makes rotor weighfeeder Pfister TRW-S/D a sturdy workhorse with low maintenance and high reliability. With the help of a special stirrer, the material is loosened and falls out of the pre-hopper, without any compression, into the rotor chambers. The weighing and dosing principle of all Pfister rotor weighfeeders is the same: by means of a weighing axis, the material weight is gravimetrically determined before material discharge, providing for a highly accurate and consistent mass stream to the pyro process.

An example of the state-of-the-art technology used in the alternative fuel installation with rotor weighfeeder Pfister TRW-S/D at Arabian Cement is a special rotary valve. Foreign objects in the material, causing blockages in other systems, are tolerated by the FLSmidth Pfister system, which is equipped with a flexible sealing lip. Multiplying the internal chambers by the rounds per minute, the valve “packs“ the fuel material into 75 small batches for steady fuel distribution to the calciner. Other providers use double pendulum flaps creating no more than eight batches.

A suction effect within the valve is barred by design. Therefore, this rotary valve does not leak air, and only the air inside the chambers will pass through the valve. This sealing principle makes it appropriate to use for the pneumatic and mechanical transport of secondary fuels. The valve compensates the air pressure between the system and the material feed piping.

Its outstanding reliability and long service life combined with high dosing accuracy and easy maintenance made rotor weighfeeder Pfister TRW-S/D the perfect choice for Arabian Cement. At the Egypt plant, the combination of fossil energy carriers such as coal, petroleum, gas, plus the mixture of alternative fuels consisting of dried sewage sludge, tire chips, plastics and packing materials now reduces energy costs considerably.

The big plus: positive effects on the incineration and therefore cement production quality since rotor weighfeeder Pfister TRW-S/D creates an absolutely reliable flow of material, tolerating various material sizes and impurities.

Due to space limitations at the existing plant, flsmidth engineers designed a balcony-type addition to the calciner tower holding the rotor weighfeeder Pfister TRW-S/D setup for dosing alternative fuels

Fuel selection as a crucial aspect
When it comes to properly feeding the great variety of alternative fuel materials into the burner, rotor weighfeeder Pfister TRW-S/D has proven its efficiency in more than 240 implementations worldwide. In 44 countries, plant management chose the FLSmidth Pfister multifuel dosing concept for reliable and flexible low-maintenance operations.

Pulverized rice husk is one of the alternative fuels dosed at Arabian Cement in Egypt

The greatest challenge in dosing alternative fuels is their diversity. Particle size, density and water content are never the same. Refuse-derived fuels (RDF) are fluffy, fibrous or compressible, and biomass or sewage sludge may contain additional moisture. Not only in the start-up phase, FLSmidth Pfister experts in alternative fuels are assisting customers in setting up the material demand profile for their respective suppliers and ensuring that materials and technical set-up are a smooth match.

Future-oriented with Pfister technology
ACC can now use various locally available fuels to cut overall energy costs and minimise its dependency on the expensive import of energy carriers. The company can react to market changes and purchase the fuels available at surplus while, at the same time, helping to protect the environment. “Materials which would otherwise end up in landfills are being put to economically intelligent use,” says FLSmidth Pfister project manager and Area Sales Manager Hassan Jrady, wrapping up the win-win situation for ACC, thanks to Pfister technology and knowhow.

Rotor weighfeeder Pfister TRW-S/D installation with the intermediate storage above

Technical data alternative fuel dosing rotor weighfeeder Pfister TRW-S/D installation at Arabian Cement in Egypt
Alternative fuels:   Mixture of dried sewage sludge (DSS) and municipal solid waste (MSW) like plastics, rubber, packing material
Mass flow:               Up to 12tph
MSW grain size:      2D: 98 wt.% < 50 x 50 mm, 100 wt % < 50 x 150 mm
Bulk density:           0.1 – 0.6 t/m3
Water content:        Max. 25%
DSS grain size:        Up to 10 x 10 x 10 mm
Bulk density:            0.5 – 0.7 t/m3
Water content:         Max. 12%

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