Tube shields having a thermal protective layer

Abstract

A tube shield, and method of manufacturing the tube shield, having a support structure with an external surface, an internal surface, and an edge, and a thermal protective layer on at least one surface of the shield support structure. The thermal protective layer is composed of a filler, one or more emissivity agent, and either an inorganic adhesive or a binder that is colloidal silica, colloidal alumina, or combinations thereof. A colorant, a surfactant, and / or a stabilizer may be incorporated into the thermal protective layer.

Description

BACKGROUND OF THE INVENTION[0001]Tube shields are found in furnaces, boilers, burners, heat exchangers, incinerators, and the like, and function to protect boiler / condenser tubes used in the generation of power, steam, condensation, heat, and the like, for a variety of applications including power generation, manufacturing and production processes, such as found in the petrochemical industries. Boiler tubes carry air, water, steam or other fluid. Condenser tubes also carry fluids in the form of gasses and liquids. Boiler tubes are exposed to an extreme heat source in a combustion chamber. Condenser tubes may be used to convert gasses to liquids, such as steam to water for recycling back into a boiler, and may also be exposed to extreme temperatures. Hot air, and / or ignited fuel, is dispensed through burner tips into the combustion chamber from external fuel sources such as coal, natural gas, biomass, slag, and the like. Under these general circumstances the mixture of fuels is eject...

AI Technical Summary

Benefits of technology

[0023]An aspect of the present invention is to extend the effective repair and replacement cycles of the heat exchangers and combustion chambers, especially tubes and tube shields. The overall cost of the utility is reduced by the concomitant reduction in maintenance costs.

[0025]An aspect of the present invention is to reduce the overall costs of operating heat exchangers or combustion chambers. Cost savings are found in the materials for replacing the damaged tubes and tube shields, in the reduction of employee work load needed to replace the tubes and tube shields, and in reduced facility downtime and economic loss.

Problems solved by technology

Condenser tubes may be used to convert gasses to liquids, such as steam to water for recycling back into a boiler, and may also be exposed to extreme temperatures.

The environment within the combustion chamber can be extremely corrosive and abrasive.

The boiler tubes employed in the combustion chamber are commonly exposed to highly abrasive and corrosive environments.

Exposure of the tubes to such environments often causes premature failure resulting in expensive maintenance and mounting boiler / facility downtime costs.

It is also known that with boiler tubes of a refuse or solid waste incinerator-type boiler, the heat-conductive performance deteriorates when soot and slag attach to the tubes requiring cleaning, and acids generated by combustion corrode the tubes, which results in deterioration of the tubes and ultimate failure.

In any case, exposed boiler tubes are subject to failure due to the hostile environment of the combustion chamber, and must be replaced frequently,

These tube shields are typically used in an effort to reduce and delay corrosion and erosion which results in eventual failure of the boiler tubes.

However, since such tube shields are readily corroded themselves with corrosive gases contained in exhaust gases, the tube shields themselves have durability of less than one year in the most hostile environments, and at worse they are corroded or eroded beyond useful life in less than three (3) months.

While conventional tube shields are designed to increase the life of the boiler tubes, they are still subject to destruction due to the corrosive environment, and must be replaced regularly.

These eddy currents increase wear, because the stream is not moving in laminar flow, as well as effecting combustion dynamics, emissions, and chemical byproducts.

Boiler tubes, and tube shields, exposed to this environment are corroded and eroded by the flow.

The high cost of energy has led society to extract usable heat from high thermal value waste streams.

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