One Response

1. Geothermal energy heat input is not constant and therefore the steam generation varies but the turbine and bypass systems to condenser are designed for fixed steam quantity. This can result in increased steam header pressures and cause unnecessary trips of the plant and therefore to control the pressure gradients which bypass systems and safety valves are not able to cope up , the extra steam generated due to irregular heat input is bypassed through a control valve vent interlocked with steam header pressure control with a set point of steam header pressure and dumps the additional steam to chimney. This avoids overheating of bypass systems, does turbine protection and also avoid lifting and failure of saftey valves. As to the above answer , part loads operation are taken care in the design of bypass systems to condenser without wasting the precious demi water (condensate) . It is only extra steam generation which is vented out because the boiler has no control of heat input since the source of geothermal energy doesn’t provide constant heat inputs to boiler. In case of direct steam use from the earth, the steam quantites are again not fixed in comparison to design of power plant and hence invites additional steam dumping through vents connected to stacks.