Summary
Due to the high demand for energy and mineral resources many dry bulk terminals around the world are expanding and seriously increasing their capacity. One approach to expansion can simply be copying the existing facilities until the required capacity is reached. In this way however the terminal does not only lose the opportunity to utilise the developments made over the last decades on terminal design, it will also end up with a costly operation. In addition it may not be able to reach the environmental restrictions imposed on terminal operations nearby environmentally sensitive areas.
This paper discusses a modern design approach of dry bulk terminals. It starts with the description of a typical dry bulk terminal. It further discusses the application of discrete event simulation as a tool to determine the best operational control of the terminal and the required number of equipment and their capacity related to the requested service level for the terminals customers. It finally points out other design aspects for terminal maintenance, dust and sound emission control methods.
Introduction – a typical bulk terminal
Dry bulk terminals are used worldwide as a buffer between either international or intercontinental transportation and inland or domestic transportation or the other way around. Bulk carriers of sizes 150,000 DWT can be loaded at a rate of 8,000 MTPH. The ore stockyard has a capacity of about 800,000 tonnes and can cater four different grades of iron ore. The ore handling facilities consist of receiving lines and shipping lines. In the receiving lines there are two rotary wagon tipplers (Tippler 1 & 2), four belt conveyors (C1, C2, C3, & C4), and two rail-mounted stackers (ST1 & ST2).
The shipping line comprises two rail mounted bucket wheel reclaimers (RE1 & RE2), six belt conveyors (S1, S2, S3, S4, S5, & S6), and two rail mounted shiploaders (SL1 & SL2). The conveyors and equipment in both the receiving and shipping lines are grouped to form two streams which are capable of functioning independent of each other as interconnected systems. It is not possible to by-pass the stockyard. More detailed information is published in [2].
The iron ore handling facility of the port of Chennai, India can be characterised by the following, when compared to other terminals around the world:
• There is no by-pass option. Some terminals have bypass facilities whereby the dry bulk can be transported directly from the incoming side (here the train side) to the outgoing side (here the exporting vessels). This not only physically not possible (no bypass conveyors) also the capacities of the incoming and outgoing side are not matched.
• According to the harbour records it takes about 40 hours to load a 150,000 DWT vessel. In theory loading a 150,000 DWT vessel can take less than 20 hours if the maximum shiploader and shipping belt conveyor capacity is reached. Due to operational issues the average capacity in this case is about 46 per cent of the maximum capacity.
This is typical for iron ore handling bulk terminals. Worldwide the average capacity of shiploading equipment varies between 40 per cent and 55 per cent. This is
not only due to operational/maintenance problems. The average capacity is calculated with respect to the total time a shiploader is available. In general it can be said that the utilisation percentage of dry bulk handling equipment normally is less than 50 per cent, where the operational availability is normally around the 80 per cent.
