Structure of a super heater
AssigneeValmet Technologies Oy
InventorsPertti Petänen, Kari Mäkelä, Kari Kuukkanen, Ari Kokko
Life of this patent
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Abstract
A method for reducing corrosion of a superheater of a steam boiler. The superheater includes a superheater piping. The superheating piping includes a steam pipe where the steam to be superheated is directed. The steam pipe is separated by a protective shell having a surface settling in the flue gas space has a temperature that rises above an upper critical temperature, above which temperature in the flue gas space the compounds from the fuel are substantially in a gaseous form. A superheater of a steam boiler and a circulating fluidized bed boiler.
Claims12
A method for reducing corrosion of a fluidized bed heat exchanger of a circulating fluidized bed boiler comprising a cyclone and a loopseal arranged below the cyclone, the method comprising:
- providing the fluidized bed heat exchanger comprising a superheater piping, the superheater piping comprising a steam pipe and a protective shell configured to separate the steam pipe from corroding compounds, the superheating piping comprising straight portions, curved portions and steam connections;
- arranging the fluidized bed heat exchanger inside a fluidized bed of the loopseal, such that the straight portions of the superheater piping are exposed to bed material and the curved portions and the steam connections of the superheating piping are arranged in the loopseal in a space separated from the fluidized bed material;
- and
- directing steam to be superheated to the superheating piping, such that a surface temperature of the protective shell is above a temperature of 600° C.
A circulating fluidized bed boiler, comprising:
- a cyclone;
- a loopseal arranged below the cyclone;
- a fluidized bed in the loopseal;
- and
- a superheater piping of a fluidized bed heat exchanger, the superheating piping comprising straight portions inside the fluidized bed of the loopseal exposed to bed material, the piping comprising a steam pipe and a protective shell that surrounds the steam pipe and separates the steam pipe from the fluidized bed material in such a manner that the surface temperature of the protective shell is arranged in use conditions above a temperature of 600° C., wherein the superheating piping further comprises curved portions and steam connections, such that the curved portions and the steam connections of the superheating piping are arranged in the loopseal in a space separated from the fluidized bed material.
Dependencies are inferred from the claim text.