Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering
Transport Technology / Logistic Engineering

H. Eil Bulk terminal simulation: a simulation model as a means of designing transhipment facilities for bulk-goods.
Masters thesis, Report 92.3.LT.3000, Transport Technology, Logistic Engineering.

Designing dry bulk terminals is a complicated task. The often complicated control rules and product flows are difficult to describe. The performance indicators of a complicated terminal model, cannot always be worked out with standard methods. Hence the need to support the design project with a simulation programme arises. The simulation programme will serve as a dimensioning tool in the design of facilities for transhipment and temporary storage of dry bulk goods. The simulation programme also has to be capable to follow the imitated unshipment process by means of animation. Animation is the first possibility to check whether the programma is working properly or not and also is an important presentation tool to the customer.

Before we can discuss the functional demands, purposes and rules of a simulation programme for dry bulk goods, a clear view of the terminal process is indispensable. In chapter 1 the terminal is studied in depth. The main object of terminal design is to render perfect service to the client at minimal costs. The choice of handling equipment is therefore of the utmost importance. In terminal design we are mainly interested in the functionality of the appliances, we distinguish peak, rated and effective capacity. The appliances can be divided into three major groups: Simulation is a synthetical method for supporting and checking the design process. We can distinguish analog and digital simulation. General rules for simulation are: keep it simple, simulate long and often, check the results as often as possible and do not expect exact answers.

For the design of a dry bulk terminal a design route has to be followed. First a function model has to be made (chapter 2). The function models are made with the Structured Analysis and Design Technique (SADT, appendix A). The main steps are: determine requirements terminal, make global design, integrate and parametrise, evaluate terminal design, specify configurations. Each of these steps will be 'zoomed in'. From the function model the data model will be made according to the Identity Relationship Method (IR-method, appendix B). The data model indicates the connection and relation between the different dataflows and the dry bulk terminal. Thereafter the menu structure is made which controls the terminal simulation programme. Finally the process description and component/attribute relation for the simulation programma is described. The order of the process is not as set as described above. During the design process feedback takes place. Hence the models are subject to changes.
When the terminal design is ready and the data for the simulation package are set, the software for the simulation model has to be chosen (chapter 3). MUST has been chosen, a simulation unit that is added to Turbo Pascal. At a later stage of the project the simulation software was changed to TAYLOR at the client's request. Taylor is a menu-controlled simulation programma and is based on nine elements of which the buffer and machines are most important. The elements can be connected in order to a model. To each element a number of fundamental entities can be adapted. For example: disturbance pattern, conditions and triggers that can manipulate the products that pass the element. After that components (products) can be guided through the system. Each component can contain a number of attributes. An attribute is a kind of information carrier.

To approach the continuous character of a dry bulk terminal, a programme has been chosen whereby the cargo of a ship is divided into sizeable amounts of cargo-units (chapter 4). At a simulated ship's arrival (generated or from a datafile) cargo-units are put into an imaginary hold. Each cargo-unit can thus be treated as an individual component. The cargo can go in three directions: direct transhipment, semi-direct transhipment, transhipment into one of the reservoirs (indirect).

When storage takes place a value can be generated that indicates the time the product spends in the reservoir before being transported. When this time has passed, the transport generator will be activated. A connection of the supply- and discharge generator has then been realised. Because adaptation of the layout is difficult to realise using Taylor, a terminal with ten generators, ten docking places, forty reservoirs and ten varying transport generators has been chosen. The amount of lay out groups that will be active during the simulation can programmed beforehand.

After the simulation is made, a validation has to take place to check whether the simulation model gives the right performance indicators (chapter 5). The testing of the performance indicators can be done based on the performance data of an existing terminal. For the validation of the terminal simulation programma the data of a terminal in Chittagong, Bangladesh have been used. The arrival data of mother vessels in '87-'88 have been used as input data for the simulation programma. The performance indicators of the simulation programme are reasonably similar to the real or calculated information.

The conclusions of the design of a dry bulk terminal simulation programma are:

Reports on Logistic Engineering (in Dutch)
Modified: 2000.04.29; , TU Delft / 3mE / TT / LT.