Systems and Methods for Heat Recovery Steam Generation at Dual Pressures

Abstract

Systems for the recovery of heat from hot air exhaust from industrial processes, and the utilization of recovered heat to generate steam at two discrete (high and low) pressures. The systems match steam production with demand. The systems utilize efficient finned tube exchange units made up of modular sections that can be selectively associated with either high or low pressure steam generators. The systems utilize separate steam domes for each of the discrete steam pressures. The steam dome components may be structured apart from the heat exchange components. Each steam dome utilizes its own sensor and control instrumentation to vary the allocation of heat recovered to either or both the high or low pressure steam generator. The two generator subsystems are linked to operate variably according to demand. Monitoring upstream heat and downstream steam requirements allow for automated operation and allocation of recovered heat into the two subsystems.

I claim: 
     
         1 . A steam generation system for recovering heat from industrial process hot air exhaust streams and generating steam at two discrete pressures, the system thereby defining a high pressure steam generation subsystem and a low pressure steam generation subsystem, the overall steam generation system comprising:
 a finned tube heat exchange unit positioned in association with the hot air exhaust streams, the heat exchange unit comprising a plurality of modular sections, the plurality of modular sections selectively associated with either the high pressure steam generation subsystem or the low pressure steam generation subsystem; and   first and second steam domes operable in conjunction with the plurality of modular sections of the heat exchange unit, the first and second steam domes discretely associated with the two steam generation subsystems, the steam domes structured and supported apart from the heat exchange unit.   
     
     
         2 . The system of  claim 1  wherein each steam dome further comprises separate control instrumentation and ancillary flow equipment. 
     
     
         3 . The system of  claim 2  wherein the ancillary flow equipment comprises level controls, pressure switches, and safety valves, the ancillary flow equipment provided to vary the allocation of heat recovered to the generation of either or both high pressure steam or low pressure steam. 
     
     
         4 . The system of  claim 1  wherein the high and low pressure steam generation subsystems are operationally linked to operate variably according to demand. 
     
     
         5 . The system of  claim 4  wherein each of the plurality of modular heat exchanger sections comprise discrete inlet and outlet connections, whereby the heat exchanger sections may be selectively directed to either the high pressure steam dome or the low pressure steam dome. 
     
     
         6 . The system of  claim 1  further comprising an upstream heat monitor for measuring a quantity of upstream heat being released and a downstream steam requirement monitor for measuring a quantity of high pressure steam required and a quantity of low pressure steam required. 
     
     
         7 . The system of  claim 6  further comprising automated control instrumentation for allocation of the recovered heat into the two subsystems within the steam generator unit.