Methods of reducing the amount of undesirable by-products in the production of polymers are disclosed. The fuel gas cooling system may be formed from one or more fuel gas supply channels terminating proximate to a spring clip at the intersection between a combustor basket and a transition section such that fuel gas may be supplied to the hot gas path proximate to the intersection between the combustor basket and the transition section. The present invention reduces noise produced by a cooling fan by controlling the fan rotation to a minimum rotational frequency in accordance with the specification and performance of the heat source. The polar component may be analyzed by Gas Chromatography and Mass Spectrometry for the one or more degradation indicators, which can provide a semi-quantitative level of such degradation indicator species. Based on the time difference between the time-shifted echo signals, a speed of a vessel is determined.