Cemtech's Bulk Material Handling webinar saw presentations from four leading specialists in the cement sector discuss a range of conveyor systems for the transport of limestone, alternative fuels, clinker and cement.

A wide bulk handling product range
Joachim Lohmann, sales director of alternative fuels at AUMUND, spoke on solutions for conveying and transport of alternative fuels (AFs). He began by introducing the Samson^® Material Feeder and the Pendulum bucket elevator type BWP, which are competitive solutions for grinding plants. Reception of AFs from walking floor trucks can be handled by AUMUND'S Trailer Docking Station, while the Chain Conveyor type TKF can move materials such as ash or FGD-gypsum at temperatures up to 300˚C at a capacity of 630tph.

AUMUND'S Rotating Screw Discharger RAS can handle refuse-derived fuel (RDF), coal, wood chips, or wood dust and uses a screw shaft to discharge material. The company's Moving Floor operates dump rates from 40 to 39m³/h or 800tph and can accommodate lump sizes up to 300mm.

A biomass case study for Samson^® in Mostostal Zabrze, Poland, recently included four Samson Material Feeders, for handling biomass with a density of 0.18-0.65t/m³ and an output of 200tph. Cement terminals can also benefit from the Samson Eco Hopper, which offers low-dust emissions at portside. The Samson^® STORMAJOR^® is a stockpiling machine that can be used to unload barges and ships up to 10dwt. Samson also has a shiploader with a boom length of 30-60m with modular wheel-mounted design.

Reducing the cost of shipunloading
Bruks Siwertell's presentation focussed on high-capacity cement unloading to save costs by reducing the time the ships are at berth. Houston Cement opted to upgrade its 800tph shipunloader with a Siwertell ST 640-D shipunloader (1500tph) with a counter-rotating Siwertell inlet feeder. Equipped with a vertical conveyor and horizontal conveyor, the unit can operate in auto-level mode to keep the inlet feeder at a constant level. The Moveable Transfer Trolley moves cement from the shipunloader to the shore conveying system in an enclosed operation. Conveyors take material to the 100,000t silos via a 70m-high bucket elevator. 

The total project gave a guaranteed performance of 1500tph rated capacity but achieved a rate of 1646tph. A through-the-ship guaranteed capacity of 1050tph was more than achieved at 1063tph and the guaranteed energy consumption of 0.40kWh/t was surpassed at 0.39kWh/t. Approximately 10Mt of cement has been handled since the terminal started in 2005 and the investment paid for itself in under two years.

Barroso flying belt's five years of operation
Stefano Cattaneo of Agudio-Leitner SpA then spoke on the achievements of the LafargeHolcim Barroso cement plant's flying belt five years after installation. The Agudio brand is used by Leitner in transport systems within the HTI group, based in Torino, Italy. The company worked on the Barroso cement plant expansion project in 2012, raising cement capacity from 1.2Mta to 3.6Mta.

Agudio-Leitner supplied a new flying belt conveyor line over 7km cutting the previous truck delivery route down from 15km. The flying belt line was suspended with 18 towers and fitted into a fully-automated ‘Crush-to-Mill’ transport system. The ropes are of locked coil type with two layers of 'Z-shaped' wires. Hauling ropes were also required with a break force of 272N. The main challenges were concave and convex curves, a 70˚ troughing angle, differences in tension, preventing extensions in the belt edges and preventing compression in the belt centre. The belt can operate at 1500tph and uses a maximum power consumption of 1750kW with a belt width of 1200m and it travels at 4m/s. 

Why not opt for a high-pressure rotary airlock?
Eric Aguilar, senior sales engineer at FLSmidth, concluded the webinar with a presentation on reducing energy consumption in pneumatic conveying using high-pressure rotary airlocks. He expressed the main obstacle for pneumatic conveyors not being installed is because of their high power consumption. The most common mode of pneumatic conveying is screw pump technology, which has a century of history behind it. Conveying compressors and screw pumps consume the most power in pneumatic conveying systems.

A lower-power alternative is the high-pressure rotary airlock charger that is used for transporting cement, fly ash, pulverised coal, petcoke and cement kiln dust. It can be used to unload railcars and to discharge storage silos. These systems can convey at pressures up to 29psig, depending on abrasion rates, and comes in six sizes with rotor volumes of 0.005-0.179cm/r. Air leakage must be checked if converting an existing system and velocities have to be checked in such circumstances.

He then gave a case study example at Tennessee Cement Terminal. As a kiln feed system, rotary feeders with an airlock compare favourably to screw pump systems. A V-Series feeder has an installed power of 6hp compared to the screw pumps 350hp, resulting in 32 per cent cost savings, Mr Aguilar claimed.

Cemtech’s next webinar will be held in March on the topic of Best Practices in Pyroprocessing.

Published under Cement News