TS-68
Murphy's Law at Sea :
Fuel Problems or Problem Fuels ?
George C. FLEISCHHACK*
ABSTRACT
An ongoing deterioration of fuel quality frequently is claimed to be reason for many desastrous engine failures. Analysing a few cases one detects that disaster normally has more than one reason. Improving the safety and reliability of marine engine operation, therefore, is a matter of assessing all negative factors contributing to failure in context
Fuel specifications, supply procedures, storage and treatment systems and operation thereof on board must be checked to identify and eliminate all factors which - alone or in combination with others - could allow desaster to happen.
In spite of Murphy's Law evidence shows that most potential failures do not happen because preventive systems and procedures are at hand and working. Such safety net is often composed of redundant elements. This carries the risk that these lead to complacency or prohibit the early identification of factors responsible for the failure.
Factors and technologies, methods and competences are analyzed with the aim to show their impact on the safety of fuel application at sea.
Key Words: ISME 2000, Heavy Fuel Oil Application, Fuel Quality, Safety, Reliability, Prevention
1. INTRODUCTION
During the second CIMAC Congress held in Milan 1953 one of the key issues was the application of heavy fuel oils on marine Diesel engines. Problems and solutions were discussed and the "deteriorating quality of marine fuel oils was criticized" [1]. Since then quality aspects, resulting from the "squeezing of the barrel" have remained on the agenda [2, 3, 4, 5].
In consequence, marine fuel oils have a bad reputation and manifold is the number of problems for which they are claimed to be the culprit.
Going into detail, however, it is found that the number of catastrophical damages to marine Diesel engines due to fuel quality is rare in recent years. There are more problems with fuels than fuels with problems along the logistical chain as outlined in "Fig. 1":
Figure No. 1: From the OEM's Spec to the Fuel Injected
1. OEM Fuel Specification
2. Purchase Contract
3. Production of Residual Material and Diluents
4. Blending
5. Transport
6. Bunkering (Transfer of Title)
7. Storage on Board
8. Treatment on Board
9. Injection and Combustion
Murphy's Law [6] says: "Things that can go wrong will go wrong. At the most inconvenient place under the most inconvenient conditions."
Such is not acceptable at sea. This paper, therefore, aims at assessing probability regimes for the factors ensuring that eventually the fuel is injected into the combustion chamber fit for purpose. Which means: providing the energy expected without harm for the engine and it's components.
2. DEFINITION OF THE LOGISTICAL CHAIN
The author believes that it is not sufficient to describe and analyze the way from the refinery to the ship. Significant pitfalls are hidden already in the process of specifying and contracting the right fuel, with some probality that the ship operator will not get what he believes to be suitable for the engine.
In the following paragraphs the nine above fuel event complexes will be analyzed. Relevant detrimental effects are considered, together with influences and / or responsibilities for their impact. Also, a model is developed helping to assess the probability of failure that must be attributed to individual impacts.
2.1 "No Risk"-Probability
To expect "No Failure" at all is unrealistic. How big is the statistical chance that a particular process goes wrong? 200 mio mtpa marine fuels delivered with an average stem of 500 mt means 400,000 bunkerings a year. In case one in a thousand would go wrong this would mean 400 "problematic" fuel events per year. The author believes this to be "significant", but feels unable to provide statistical figures. This could be a task for the CIMAC Working Group "Users" who have the necessary information in their data bank. It is, therefore, in this paper spoken of three probability classes :
- High probability: conformance in 999 of 1000 cases
- Significant probability: conformance in 99 of 100 cases
- Insignificant probability: conformance in less than 9 of 10 cases.
