Modifying the Chimney Arrangement of an Indirect Water Bath Heater Without Affecting its Operational Efficiency

摘要

Because of the operation in offshore platforms, sometimes it is impossible to change the location of any equipment due to time, space or costs. For these reasons it is important to be able to adapt equipment, and change its/their configuration without affecting its operation or efficiency. This particular case is focused in the configuration change of chimneys of indirect heat exchangers, which operate with natural gas as a fuel, when natural gas of two production wells are heating through a water bath. The change of configuration of chimneys consists of relocating only the chimneys farther than the original locations next to the indirect heat exchangers located in the superior cover of an offshore natural gas production platform. Before changing the original arrangement of chimney, it is important to evaluate the equipment behavior with its original configuration to know its behavior. After that it is possible to apply the principle of differential pressure because of difference of densities between ambient air and flue gases, called chimney effect or natural draught. This phenomenon allows to compensate the pressure drop due to the increase of the length of line to send the flue gases to atmosphere, considering a sufficient height of the chimney. However, it is important to make an appropriately height estimation to avoid changes or affecting the performance and operation of the heating equipment. Adaptations over the chimney systems of indirect water bath heaters with natural draft and natural gas as a fuel produce acceptable results in the equipment behavior without blower installation. This paper shows that it is possible to change the configuration of the flue gases system of an indirect water bath heater to heat natural gas using natural draught without affecting its operation after the configuration changes. An important key that shall be considered is the climatological variations that could affect the natural draught, and chimney diameter.