The demand of Natural Gas (NG) is growing every year, implying the search for new optimization technologies for processing, liquefying, storing, and transporting the gas to distributors by ducts networks. Currently, for short distances from shore, NG is transported by pipeline to be processed primarily and liquefied in land. This route, in some cases, difficults and burdens costly the production chain, since it involves operational difficulties and high costs to construct and to maintain long gas pipelines (above 200 km) in order to send the gas to shore. Given this scenario, it has become increasingly usual and economical the overall liquefaction process where fuel is to be carried on board the same ship where natural gas is processed primarily and stored as a cryogenic. The denomination Floating and Liquefied Natural Gas (FLNG) is attributed to the vessel which accommodates these steps altogether. This paper analyzes different liquefaction processes and suggests parameters to reduce the subjectivity of the decision-making about the most favorable technologies. The adopted parameters include the weight and the stability of process equipment, lay out area occupied on the ship production deck (topside), need for classification areas, inventories and handling of flammable refrigerant mixtures (for liquefaction cycle), different types of containment systems for the produced cryogenic fuel, offloading, cargo handling (sloshing) during the production works in deep waters, movement of the ship in harsh metocean conditions. In addition to these parameters, other aspects are also analyzed such as thermodynamic efficiency indicators, material and energy balances for the main process design. Among various methodologies for the structured decision-making, the Multi Criteria Decision Aid (MDA) supported by using the Analytic Hierarchy Process (AHP) process, has been chosen since it is an expedite methodology envisaging possible solutions with value aggregation to the variables of the problem.