Hydrocarbon-fired water heater

Thus, we find that the efficiency of the hydrocarbon-fired water heater is... 

For safely reasons, heaters are most often used to heat a heal medium system (water, steam, or heat transfer fluid) rather than to heat the gas or oil stream directly. If the fluid to be heated contains hydrocarbons, (lie heatci can he located safely away from other equipment, If it catches on fire, damage can be limited. 

In an emergency the control systems will shut down the reactors by inserting control rods into the core (this is known as a scram ). Unfortunately, this action does not immediately stop the nuclear reaction. Heat continues to be generated in the nuclear core even after shutdown, so it is essential that all three of the water systems continue to operate so that heat can continue to be removed for many hours. This need for on-going cooling is in contrast to most process plants in the hydrocarbon industry—a shutdown will immediately remove sources of heat, and temperatures will immediately start to fall to a safe value. Hence, the continued operation of cooling systems is not likely to be so critical (except maybe with respect to the high temperature firebrick on the inside of fired heaters). 

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