Arrangement of heat recovery surfaces of a recovery boiler

A chemical recovery boiler comprising:

• a furnace configured to combust waste liquor;
• a smelt outlet in a lower region of the furnace and configured to discharge smelt produced in the furnace from the combustion of the waste liquor, and
• a flue gas duct coupled to an upper region of the furnace and including vertical flue gas channels, each of which includes a heat recovery unit configured to recovery heat from flue gases passing through the flue gas duct,
• wherein the heat recovery units each include heat recovery elements,
• wherein the flue gas channels include a first flue gas channel which is immediately downstream of the furnace and is provided with a reheater;
• wherein the heat recovery unit of the first flue gas channel includes at least one of an economizer and a boiler bank,
• wherein, in the first flue gas channel, the heat recovery unit and the reheater are positioned side by side along a direction crosswise with respect to a horizontal incoming direction of the flue gases from the furnace so that in the first flue gas channel the flue gases flow downward and simultaneously across the heat recover unit and the reheater.

A recovery boiler including:

• a furnace configured to combust waste liquor and including an inlet to receive the waste liquor and an outlet for chemical smelt produced by the combustion, wherein the furnace includes walls extending vertically to confine and direct upwards flue gases generated by combustion;
• superheaters arranged in an upper region of the furnace;
• vertical flue gas channels adjacent and horizontally offset from the furnace, wherein the vertical flue gas channels include a first channel attached to the furnace and having a flue gas inlet in an upper region of the first channel and a flue gas outlet at a bottom region of the first channel, wherein the inlet receives flue gases flowing downstream from the superheaters;
• wherein the first channel includes a reheater and a heat recovery unit and the heat recovery unit is at least one of an economizer and a boiler bank,
• wherein the reheater and heat recovery unit in the first channel are arranged to simultaneously receive flue gas flowing down through the first channel,
• wherein the other vertical flue gas channels include updraft flue gas channels each having a lower inlet and an upper outlet, and downdraft flue gas channels each having an upper inlet and a lower outlet,
• wherein a first of the updraft flue gas channels is between the first channel and a first of the downdraft flue gas channels, and the other updraft flue gas channel(s) are between successive ones of the downdraft flue gas channels, and
• wherein the downdraft flue gas channels each have at least one of an economizer and a boiler bank.