US 5,538,420 A · Heat exchanger bake out process

Abstract

A heat exchanger burn-out process for regenerative thermal oxidizers includes the steps of passing a super-heated gas through one of the heat exchangers and into the combustion chamber. The gas is preferably heated in a selectively opened injection line that includes a burner. The burner is designed to superheat the injection gas to a cleaning temperature. The cleaning temperature is selected to be high enough as to volatilize and/or combust the organic solids that are expected within the heat exchanger. The injection line is associated with one of the heat exchangers, and the other two of the normal three heat exchangers on the regenerative thermal oxidizer are switched between a supplemental injection mode, wherein cooling gas is injected through that heat exchanger, and an outlet mode wherein gas from the combustion chamber leads outwardly through the heat exchanger to an outlet manifold. The supplemental injection line reduces the overall temperature of the gas leaving the system through the outlet manifold. In one embodiment, the heated injection line is associated with the inlet manifold, and the supplemental injection line is associated with the purge manifold. In a second embodiment, the heated injection line is associated with the purge manifold and the supplemental injection line is associated with the inlet manifold.

Claims13

Dependent claims

A method of cleaning a heat exchanger in a regenerative thermal oxidizer comprising the steps of:

providing a regenerative thermal oxidizer including a combustion chamber and at least two heat exchangers, each of said heat exchangers communicating with said combustion chamber at a first end of said heat exchanger and communicating with a source of process gas to be cleaned at a second end of said heat exchanger, said second end of said heat exchangers also communicating with an outlet manifold to direct a clean gas passing from said combustion chamber through said heat exchangers and to a destination for clean gas;
providing an injection line for passing a heated gas into said heat exchanger through said second end towards said first end and into said combustion chamber, a valve being provided on said injection line and a source of heat being provided on said injection line upstream of said valve;
heating and injection gas in said injection line with said source of heat;
and
passing said heated injection gas through said injection line and into said heat exchanger at said second end, passing said gas over said heat exchanger from said second end toward said first end and into said combustion chamber through a first of said heat exchangers, and passing gas from said combustion chamber through a second of said heat exchangers to said outlet manifold.

2 more elements

A method of cleaning a heat exchanger in a regenerative thermal oxidizer comprising the steps of:

providing a regenerative thermal oxidizer including a combustion chamber and at least two heat exchangers, each of said heat exchangers communicating with said combustion chamber at a first end of said heat exchanger and communicating with a source of process gas to be cleaned at a second end of said heat exchanger, said second end of said heat exchangers also communicating with an outlet manifold to direct a clean gas passing from said combustion chamber through said heat exchangers and to a destination for clean gas;
providing an injection line for passing a heated gas into said heat exchanger through said second end towards said first end and into said combustion chamber;
passing a heated injection gas through said injection line and into said heat exchanger at said second end, passing said gas over said heat exchanger from said second end toward said first end and into said combustion chamber through a first of said heat exchangers, and passing gas from said combustion chamber through a second of said heat exchangers to said outlet manifold;
said gas passing into said injection line being heated to a cleaning temperature selected to be high enough to volatilize organic solids which are expected to be on said heat exchanger;
and
wherein there are at least three of said heat exchangers, with a first of said heat exchangers receiving said heated gas, a second of said heat exchangers receiving said outlet gas, and a third of said heat exchangers passing a cool supplemental injection gas through said third heat exchanger from said second end toward said first end and into said combustion chamber.

3 more elements

Dependencies are inferred from the claim text.

Heat exchanger bake out process

Life of this patent

Heat exchanger bake out process

Life of this patent

Abstract

Claims13