Method and arrangement for generating process steam
AssigneeAndritz Inc.
InventorAki Muhli
Life of this patent
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Abstract
A method and an arrangement for generating process steam at a chemical pulp mill. Water is heated by subjecting it to an indirect heat exchange contact with steam in a heat exchanger. The water is heated with live steam produced in a steam boiler for generating process steam, whereby the live steam is condensed and the generated condensate is recovered. The process steam is subjected to a direct heat exchange contact with a material for heating the material. The water used for process steam production is obtained from secondary condensates, purified waste water and/or raw water. Process steam can be used in the treatment of cellulosic fibrous material, such as chips.
Claims18
A method of producing process steam at a chemical pulp mill, the method comprising:
- heating water in a heat exchanger in which the water is subjected to indirect heat exchange contact with live steam produced in a steam boiler, wherein the water is free of volatile compounds and the heated water is output from the heat exchanger as process steam,
- condensing the live steam in the heat exchanger and recovering condensate resulting from the condensing of the live steam, and
- heating a material by direct heat exchange contact between the material and the process steam output from the heat exchanger.
A method of producing process steam at a chemical pulp mill, the method comprising:
- heating water in a heat exchanger in which the water is subjected to indirect heat exchange contact with live steam produced in a steam boiler, and outputting the heated water from the heat exchanger as process steam,
- condensing the live steam in the heat exchanger and recovering condensate resulting from the condensing of the live steam,
- heating a material by direct heat exchange contact between the material and the process steam output from the heat exchanger, and
- preheating the water to be heated to produce the process steam with black liquor discharged from a digester or flash steam from the black liquor.
A method to produce process steam in a chemical pulp mill, the method comprising:
- feeding live steam generated in a boiler into a heat exchanger, condensing the steam in the heat exchanger, and outputting condensate of the steam from the heat exchanger;
- feeding water free of volatile compounds into the heat exchanger, heating the water in the heat exchanger to produce process steam using heat energy extracted from the steam condensed in the heat exchanger;
- outputting the process steam from the heat exchanger into a conduit which directs the process steam into a separation tank in which a portion of the process steam condenses into water;
- outputting the process steam from the separation tank into a conduit which directs the process steam to directly heat a process material being processed in the chemical pulp mill;
- and
- outputting from the separation tank the water condensed in the separation tank as the water fed into the heat exchanger.
A method to produce process steam in a chemical pulp mill, the method comprising:
- feeding steam produced in a boiler into a heat exchanger, condensing the steam in the heat exchanger, and outputting condensate of the steam from the heat exchanger;
- feeding water into the heat exchanger, heating the water in the heat exchanger to produce process steam using heat energy extracted from the live steam condensed in the heat exchanger;
- outputting the process steam from the heat exchanger into a conduit which directs the process steam into a separation tank in which a portion of the process steam condenses in water;
- outputting the process steam from the separation tank into a conduit which directs the process steam for use in the chemical pulp mill, wherein the process steam output from the separation tank is applied to heat chips in a chip bin, and
- outputting from the separation tank the water condensed in the separation tank for use as the water fed into the heat exchanger.
Dependencies are inferred from the claim text.