US 4,083,398 AGranted

Waste heat recovery system

AssigneesJohn F. Fallon, Jr., Donald Ritt

InventorsJohn Joseph Fallon, Jr., Joe Bob Blair, Donald Roy Phelps

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Abstract

A system for recovering the waste heat normally exhausted into the atmosphere by chemical or other processing plants. The invented system comprises a substantially self-contained apparatus for receiving hot exhaust gases and extracting the waste heat therefrom for some beneficial use, such as pre-heating inlet air in an inlet plenum. The system may include temperature and pressure controls which enhance the safety and efficiency of the system's operation, and further may include flow controls in a multiple burner installation so that the desired fuel air ratios and heat distribution may be achieved. By building the present invention as a substantially self-contained and self-supporting assembly, on site installation time and the required alternation of pre-existing on site equipment may be minimized, thereby affecting substantial economic savings by minimizing the resulting down time of the processing plant. Embodiments for a single burner nest heater, multiple nest cabins and grade level stack systems are disclosed.

Claims22

Dependent claims

An apparatus adapted for coupling to a furnace installation which comprises a burner, an inlet air plenum and a vertically disposed exhaust stack, for recovering the heat energy in waste gases produced in said burner and escaping through said stack, and for delivering said recovered waste heat to inlet air flowing through said inlet air plenum, said apparatus comprising:

(a) a vertically disposed, self-supporting, frame structure;
(b) an exhaust gas duct for carrying exhaust gas therethrough, said exhaust gas duct being mounted to an upper portion of said frame structure and being mechanically coupled to and in communication with said stack;
(c) a first heat exchanger means having an inlet and an outlet for receiving and discharging a heat transfer fluid, said first exchanger means being disposed within said exhaust gas duct for absorbing heat from said exhaust gas flowing therethrough;
(d) an inlet air duct for carrying inlet air therethrough, said inlet air duct being mounted to a lower portion of said frame structure and being mechanically coupled to and in communication with said inlet air plenum;
(e) a second heat exchanger means having an inlet and an outlet for receiving and discharging said heat transfer fluid, said second exchanger means being disposed within said inlet air duct for heating the inlet air passing therethrough, the inlet of said second heat exchanger means being in communication with the outlet of said first heat exchanger means, and the outlet of said second heat exchanger means being in communication with the inlet of said first heat exchanger means through conduit means so as to define a flow circuit for said heat transfer fluid;
(f) a reservoir for maintaining a reserve of said heat transfer fluid, said reservoir being mounted on said frame structure and being in communication with said flow circuit;
and
(g) pumping means for circulating said heat transfer fluid through said flow circuit, said pumping means being mounted on said frame structure and being in communication with said flow circuit,
whereby, said apparatus may be brought to the site of said furnace installation, disposed adjacent thereto and inter-coupled to said exhaust stack and said inlet air plenum without placing a load on said furnace installation.

6 more elements

In a system for recovering the heat energy in the waste gases from a furnace installation comprising (i) a first heat exchanger means for absorbing heat from said exhaust gas, and having an inlet and an outlet for receiving and discharging a heat transfer fluid;

(ii) a reservoir for maintaining a reserve of said heat transfer fluid, said reservoir being in communication with said first heat exchanger means;
and (iii) pumping means for circulating said heat transfer fluid through said first heat exchanger means, said pumping means being in communication with said first exchanger means, the improvement comprising:
(a) a vertically disposed, self-supporting, frame structure having affixed thereto at an upper portion thereof an exhaust gas duct for carrying said exhaust gas therethrough, and at a lower portion thereof an inlet air duct for carrying inlet air to said furnace installation therethrough, said exhaust gas duct being adapted for coupling to an exhaust stack of said furnace installation and for receiving and supporting said first heat exchanger means therein, and said inlet air duct being adapted for coupling to an inlet air plenum of said furnace installation;
and
(b) a second heat exchanger means having an inlet and an outlet for receiving and discharging said heat transfer fluid, said second exchanger means being disposed within said inlet air duct for heating the inlet air passing therethrough, the inlet of said second heat exchanger means being in communication with the outlet of said first heat exchanger means, and the outlet of said second heat exchanger means being in communication with the inlet of said first heat exchanger menas through conduit means so as to define a flow circuit for said heat transfer fluid, said second heat exchanger means comprising (i) an inlet manifold in communication with said inlet thereof;
(ii) an outlet manifold in communication with said outlet thereof;
(iii) a plurality of fluid conducting tubes coupled to and in communication with said manifolds, said conducting tubes each providing a multiple pass flow path for said heat transfer fluid;
and (iv) a pluraity of plates perpendicularly disposed along the length of said conducting tubes, said plates being in contact with said exhaust gas,
whereby, said system may be brought to the site of said furnace installation, disposed adjacent thereto and inter-coupled to said exhaust stack and said inlet air plenum without placing a load on said furnace installation.

6 more elements

Dependencies are inferred from the claim text.