Acurex Corporation

Alzeta Corporation

The United States of America As Represented by the United States

The United States of America As Represented by the Administrator of the

Gas Research Institute

The United States of America

John P Kesselring

Robert M Kendall

Wayne V Krill

Richard J Schreiber

William C Pfefferle

John J Lannutti

Meredith J Angwin

G Blair Martin

Michael A Lukasiewicz

Edward K Chu

A gas-fired radiant tube that employs heterogeneous catalytic combustion, and a high combustion efficiency, low NO.sub.x catalytic combustion radiant tube heating system, incorporating the radiant tube, are disclosed. In the system, essentially mirror image, combined inlet/exhaust units containing heat regenerator units are connected at opposite ends of the catalytic combustion tube. Combustion flow is cycled back and forth through the units and the combustion tube so that during any given cycle the hot exhaust gases heat the regenerator in the exhaust side of the flow for preheating the inlet gases during the next, reversed flow cycle and the natural gas fuel is completely oxidized. Thus, the cycled flow completely consumes the fuel and constantly preheats inlet air so that the sytem provides both high combustion efficiency and high thermal efficiency.

Radiant tube heating system

The burner system is adapted for retrofit into the combustion chambers of firetube boilers. The burner is comprised of a hollow shell molded from a porous ceramic fiber matrix. Fuel and air reactants flow outwardly through the fiber matrix shell and are combusted along a shallow reaction zone on the outer surface. Heat is transferred primarily by radiation to the walls of the combustion chamber at temperatures which result in relatively low NO.sub.x emissions and high combustion efficiencies as compared to boiler systems with conventional burners.

Firetube boiler heater system

Water heaters are provided which exhibit improved efficiency and emissions performance over conventional water heaters, comprising condensing heat exchanger means and infrared fiber matrix burner means to achieve said improved performance.

High efficiency, reduced emissions water heater

A process and system of operation for combusting nitrogen-containing fuels with resulting low NO.sub.x emissions. A fuel-rich mixture of the fuel is combusted in a catalytic bed which is carried by a support structure. Active or passive means are provided for limiting transfer of heat from the bed into the support structure for minimizing formation of NO.sub.x during combustion. The active means for limiting the heat transfer includes, in different embodiments, electrical resistance back heating, induction back heating, exhaust gas back heating, and combustion fired back heating. The passive means for limiting the heat transfer includes, in different embodiments, a body of heat insulating material between the bed and support structure, or the insulating effect of the outer cells of the bed within a recess in the support structure.

Catalytic combustion process and system with wall heat loss control

A gas-fired, forced air furnace system employing a fiber matrix burner element and a condensing-type heat exchanger to achieve both high system thermal efficiency and low emission of NO.sub.X and other gaseous pollutants. The value of excess air in the fuel-air reactants supplied to the ceramic fiber matrix burner is selected to be equal to or greater than ten percent to provide NO.sub.X emissions below fifteen ppm on an air-free basis, with CO and HC emissions substantially comparable to those from existing furnaces, and the surface area of the condensing portion of the heat exchanger system is designed to produce sufficient condensation of moisture in the combustion gasses to produce an overall system thermal efficiency of at least about ninety percent.

Catalytic gas-fired furnace system and method

A process and system for combusting a nitrogen-containing fuel to produce low NO.sub.x levels in the exhaust emissions. A stream of the fuel mixed with air is combusted in two or more fuel-rich zones having catalytic beds. The stoichiometry of the mixture in each zone is controlled for the particular catalytic material employed so that a minimum of NO.sub.x precursors is formed upon combustion in the zones. Additional air is injected into the flow to maintain the predetermined stoichiometry in the downstream zones. The beds of the fuel-rich zones can be comprised of different catalytic materials having different theoretical air proportion at which the NO.sub.x precursors are at a minimum. The beds of the fuel-rich zones can also be comprised of the same catalyst material having different minima at which NO.sub.x precursors are formed at different theoretical air proportions. A final zone combusts the exhaust products at a stoichiometry of at least 100% theoretical air to substantially complete combustion of fuel. Means can be provided for extracting heat from the flow between the combustion zones.

Multiple stage catalytic combustion process and system

A catalyst system in which the catalytic composition comprises a catalytically active material which is homogeneously interspersed throughout a monolith structure of ceramic composition. The composition is shaped into a unitary monolith which is employed as the catalyst structure. In the method the active material or materials are admixed with a ceramic material, which can be either active or inactive, in finely divided form and then shaped into the monolith structure.

Catalytic monolith and method of its formulation

A process and system of apparatus for stoichiometrically combusting fuel and air reactants. A stream of the reactants is directed through an upstream zone for combustion about cylinders comprised of a catalytic material. A plurality of heat sink conduits are spaced about the cylinders for absorbing radiant energy from the cylinders, and a coolant medium is directed through the conduits for extracting thermal energy at a controlled rate. Products from the upstream zone are directed through a combustor in a downstream zone for adiabatic combustion, and products from the combustor are directed in heat exchange relationship with a coolant medium which extracts residual energy from the stream.

Catalytic combustion process and system

Combustion process and apparatus which includes a monolith bed through which a mixture of fuel and oxidizer reactants is directed. The initial segment of the bed is formed with cells of an optimum size for causing the reactants to undergo heterogeneous combustion without blowout. One or more downstream segments of the bed are formed with cells of a size smaller than the upstream cells to achieve substantially complete combustion in a bed of relatively compact dimensions. High mass flow rates are obtained under stable combustion conditions with high combustion efficiency and low emissions.

Growing community of inventors

Mountain View, CA, United States of America

John P Kesselring