Patent ID: 7891324

Claim:
A heater having a liquid inlet, a hot liquid outlet, a hot gas inlet and a cooled gas outlet and adapted to heat a liquid stream by heat exchange with a hot gas stream to produce a hot liquid stream and a cooled gas stream; the heater consisting essentially of: a) a radiant/convection heat transfer first section, a first section liquid inlet, a first section liquid outlet, a first section gas inlet and a first section gas outlet adapted to cool a hot gas stream by heat exchange with a liquid stream to a temperature to produce a hot liquid stream at the first section liquid outlet and a reduced temperature gas stream at the first section gas outlet at a temperature suitable for passage through a selective catalytic reduction unit; b) a selective catalytic reduction unit having a reduction unit inlet in fluid communication with the first section gas outlet adapted to pass the reduced temperature gas stream to a reduction unit gas outlet where the selective catalytic reduction unit is operated at a suitable temperature range from about 750 to about 550° F.; c) a convection heat transfer section adapted to cool a hot gas by heat exchange with a liquid having a second section liquid inlet, a second section liquid outlet in fluid communication with the first section liquid inlet, a second section gas inlet in fluid communication with the reduction unit gas outlet; and, d) a waste heat recovery section having a waste heat recovery section liquid inlet, a waste heat recovery section liquid outlet in fluid communication with the second section liquid inlet, a waste heat recovery section gas inlet in fluid communication with the second section gas outlet and a waste heat recovery section gas outlet.