Ham petrol tankeri kargo tankları ısı transferi ve kargo ısıtma sistemi analizi

Crude oil is one of the most actively traded commodities in the world. Oil transportation has become a complex and highly technical operation. One of the major difficulties in the transportation is the high viscous fluids that require efficient and economical ways to transfer the heavy crude. Heavy crude oils have a density approaching or even exceeding that of water. They are usually extremely viscous, with a consistency ranging from that of heavy molasses to a solid at room temperature. Heavy crude oils are not pumped easily through the pipelines because of the high concentrations of sulfur and several metals, particularly nickel and vanadium. Crude oils are complex fluids that can cause a variety of difficulties during the production, separation, transportation and refining of oil. One of the most prominent challenges is transportation of heavy and extra heavy crude oil from ship to the station. The transportation of heavy and extra-heavy oil presents many operational difficulties that limit their economical viability. Therefore, solving this operational difficulties is very essential due to the economical aspects in terms of increasing use of heavy and extra heavy crude oil in the future. The most widely and efficient enhanced oil recovery technologies are the thermal techniques. Thermal methods reduce the viscosity of heavy crude oil by several orders of magnitude rapidly, in contrast to non-thermal methods in which the mode of viscosity reduction is quite slow. Heating is a common method utilized to overcome the above noted problems of transporting heavy oil from ship to the station. The basis for this method lies in the fact that as heavy oil is heated, the viscosity of the heavy oil is reduced and thus made easier to pump. Therefore it is important to heat the oil to a point where the oil has a substantially reduced viscosity. This method is aimed at reducing viscosity as well as the energy required for pumping, to enhance flowability of the oil. However, heating to increase the temperature of the fluid involves a considerable amount of energy and cost as well. Thus, identifying correctly the heating system requirements, development of appropriate heating system, calculating correctly the factors that affect heat transfer rate is important in terms of energy conservation ,environment effectiveness and cost. This thesis aims to develop appropriate cargo heating system, to determine correctly the heating system requirements, calculating correctly the factors that affect heat transfer rate, to determine the optimal cargo heating management plan,in terms of energy conservation, saving cost depend on fuel consumption and environment effectiveness. Furthermore, this thesis is aimed to find optimal methods scientifically to determine the cargo oil heating time in order to save energy during oil transportation. In this thesis, in the first section presents general information, purpose and scope and literature review about development of cargo oil heating system and plan in oil tankers. In order to accomplish our purpose which was mentioned above, initially 100,000 dwt crude oil tanker (aframax) preliminary design is performed in the second section. In addition to this part, aframax tanker`s main dimensions and its cargo tanks capacities which are necessary to calculate heat transfer rate and coefficients are determined in this chapter. Additionally, crude oil tanker main engine and generating sets are identified and selected. In the third section, general theories of conduction and convection heat transfer are described. Natural and forced convection correlations for vertical and horizontal plates are explained in briefly. In the next chapter, Shell and Spirax Sarco cargo heating systems solutions are analyzed and examined with the values which are written in their literature. In this examination, quantity of heat requirements for Shell and Spirax Sarco are calculated and then these heat requirements for both solutions are compared with each other. Finally, steam consumptions for this cargo heating solutions are determined and compared. In the fifth section, heat transfer coefficients for each section of cargo tanks are calculated under different conditions independently. Spirax Sarco and Shell heat transfer coefficients which are written their literature for double side, deck and double bottom are compared with independent solution of heat transfer coefficients for double side, deck and double bottom. Heat requirements differences occured due to the heat transfer coefficients differences between Shell, Spirax Sarco and our independent solutions and heat requirements for each solutions are compared. Additionally, these two solutions and our independent solution's boiler fuel consumption onboard crude oil tanker is compared with each other. In the sixth section, modeling of heat transfer from heat equipment to the cargo is performed. Cargo heating methods are explained and appropriate one which is called submerged heating coil is implemented to proposed design ship. Finally, discussions and reviews of the obtained numerical results are discussed in the last section of the thesis. Suggestions for any academic studies, research and development in the future are mentioned in final part.