Cement Dispatch Terminals in Latin America The selection of proper dispatch equipment at a cement terminal could mean substantial savings in the total production cost. In the final part of this three-part series, we discuss specific bulk dispatch terminals

Dispatch in bulk Aside from bags, the other way that cement can be dispatched is in bulk. Truck or railcar filling capacities vary between 100 and 300 tph. The loading system has to be designed to handle these capacities with minimum dust generation, and it should allow for the positioning of the loading spouts on the loading openings in a shortest possible time. The following equipment generally integrates a bulk loading system:

- Conveying equipment from the storage system to the truck loading point. This system comprises of one or several fixed or mobile airslides of multiple discharges. (Figure 1).

- Loading spout. The bellow-type loading spout has to be able to handle not only the capacity of product to be loaded, but also the excess of dust generated during the loading operations.

The standard design of these components consists basically of a retractile central chute for loading the product. A ring-reinforced canvas covers this chute. The space between the canvas and the chute is used to dissipate the excess of dust and air generated during the loading operation.

The air to be vented when a truck is loaded is equal to three times the volume of the truck being loaded. The positioning of the loading spout is carried out by means of a winch.

- Dedusting system. One of the most important pieces of equipment in a bulk loading terminal is the dust suppression system. An efficient dust suppression system is comprised of ventilation ducts, dust collector, and vent.

The basic operation of a truck loading system is as follows: An empty truck is positioned on the appropriate scale. The truck weight is measured by the scale and recorded. The appropriate loading spout is positioned and lowered into the loading opening, then the loadout system dust collector fan is automatically started. The filling rate, cement silo, and cement type is selected.

The filling process is carried out until full limit is reached as indicated by the scale. The loading spout is raised, the loadout system dust collector shuts down, and the final weight of the truck is measured by the scale and recorded. The next truck is moved into position and the loading process is started again.

Marine terminals Some plants, taking advantage of their geographic location, can dispatch the cement by sea, not only for exporting but also for distributing this product locally. Through a marine terminal, it is possible to dispatch cement in bulk and in bags. The general arrangement of the ship-loading system is determined based upon the following main parameters:

- Total annual throughput capacity;

- Total loading capacity (tph);

- Pier general arrangement;

- Environmental conditions (tides, currents, etc.); and

- Dead weight tonnage (dwt) of the vessels to be loaded.

Loading equipment Depending on how the cement will be dispatched, the product is conveyed from storage building or silo to the pier by means of a belt conveyor, screw conveyor, airslide, fork-lift, trucks, etc. The conveying system moves the cement to the shiploader, which trims the product uniformly inside the cargo hold by means of a loading arm. Based upon the principle used by the loading arms, the shiploaders can be classified as shown in Figure 2.

Conclusion Most of the cement companies in Latin America are up grading their production and dispatch systems to reduce the total production costs in order to be more competitive to face the requirements of the local market of the new millennium.