Raw Material Delivery

The scope of the analysis aims to identify the process under consideration, in which plant it will take place, and with which chemicals it will be performed. The chemical reactions and unit operations must be clearly characterized. In this step, it is also important to check for interface problems with other plant units. As an example, when considering raw material delivery, it can be assumed that the correct raw material of the intended quantity and quality is delivered from a tank farm. Thus, it can be referred to the tank farm risk analysis, or the tank farm is to be included in the scope of the analysis. Similar considerations can be made for energy supply, to ensure that the appropriate energy is delivered. Nevertheless, loss of energy must be considered in the analysis, but it will be assumed that... 

Because raw-material delivery carmot be accurately predicated, on account of unforeseen events such as bad weather, strikes, accidents, etc., storage of raw materials is a necessity. Similarly, the demand for products can be unpredictable. Also, internal storage of chemical intermediates may be required to maintain steady operation of a process containing batch operations or to store chemical intermediates temporarily if downstream equipment fails. Production can continue when repairs are completed. 

Class 3 Joint Raw Material Delivery and Lot Sizing Problems (Al, B2, C2)... 

We first describe a basic model which will be used as a reference point when we review existing results in this area. A manufacturer purchases raw material from a supplier, and uses the raw material to produce a final product, and ships a fixed quantity of the product to a customer periodically to satisfy the customer s constant demand. The size and timing of the shipments are specified by the customer. The manufacturer has a single production line with a constant production rate. There are four cost components in the system (1) distribution cost for delivering raw material from the supplier to the manufacturer, (2) inventory cost for holding raw material at the manufacturer (3) production cost at the manufacturer (there is a fixed setup cost for each production run), and (4) inventory cost for holding finished product at the manufacturer. The problem is to find a joint cyclic raw material delivery and production schedule such that the total cost per unit time is minimum over an infinite planning horizon. 

Raw material delivery cycle time and production cycle time are equal, i.e. lot-for-lot. 

There are an integer number of equal-sized raw material delivery cycles within each production cycle. 

Extending from joint raw material delivery and lot sizing problems, one can consider a more general model involving three stages raw material delivery. 

Raw material delivery cycle length equal to production cycle length... 

Integer number of equal-sized production cycles within each raw material delivery cycle... 

Deliver timely shipments Early dehvery can be as harmful to the company s future as late delivery, because buyers then must accommodate early deliveries with additional storage capacity. Ideally, the planning should allow for exact delivery when the customer demands. At the same time, there must be sufficient labor and raw material delivery in the exact proportions to meet the deadlines without having to pay extra for overtime. 

Chemithon findings are in agreement with the above statements mole ratio was found to be the most important variable. Mole ratios between 1.01 and 1.03 yielded 1,4-dioxane values from less than 20ppm to 50ppm on 100% active matter with Shell feedstock Neodol 25-3 (3 moles EO). Free oil concentrations were 2.0% on 100% active matter. Higher mole ratios caused a dramatic increase in 1,4-dioxane. Mole ratios above 1.05 easily led to levels of several hundred ppm. From these results, it is clear that precise raw material delivery systems must be employed. 

When I tour around a plant for the first time, I always ask about and want to understand the product flow. I want to walk the flow starting with raw material delivery and ending with the shipment of finished goods. Product flow can be defined at the plant, department, and work cell level. The product can be physical parts, information, or in the case of a hospital, real people. 

Two main SC issues were identified through the discussions with the case companies. The first is raw material ordering with regard to finished goods production planning in the presence of multiple types of uncertainties. For both companies, there are lots of uncertainties in their SC, for example, raw material delivery lead time is subject to not only the inventory availability at the suppliers, but also the traffic conditions on the way from the suppliers to the raw material warehouse. 

---