Metallurgical plant with efficient waste-heat utilization

Abstract

A metallurgical plant has a plant positioned upstream of a steel-generating plant and has a gas-generating plant which generates an export gas. Carbon dioxide and/or water contained in the export gas is removed from the export gas in a separation device. A resulting product gas is heated, before being supplied to the upstream plant, in a firing unit through the combustion of a heating gas. Excess thermal energy produced during the combustion of the heating gas which is not used for heating the product gas is thermally utilized. The utilization may take place within the firing unit through steam generation and/or downstream of the firing unit to preheat the heating gas and/or an oxidation gas used for the combustion of the heating gas and/or through the pre-heating and/or drying of raw materials to be supplied to the upstream plant and/or to the gas-generating plant.

1 - 16 . (canceled) 
     
     
         17 . An operating method for a facility comprising a gas-generating plant, a steelmaking plant and an upstream plant disposed upstream of the steelmaking plant, the method comprising:
 generating an export gas in the gas-generating plant;   removing carbon dioxide and/or water from the export gas, the carbon dioxide and/or water being removed in a separation device to produce a product gas;   heating the product gas in a firing device to produce a heated product gas, the product gas being heated by combusting a heating gas to produce a flow of flue gas;   supplying the heated product gas to the upstream plant;   supplying the heating gas to the firing device in quantities significantly greater than are required for heating the product gas;   using excess thermal energy produced during combustion of the heating gas in at least one of:
 generating steam in the firing device; 
 preheating and/or drying raw materials supplied to the upstream plant and/or supplied to the gas-generating plant, the raw materials being preheated and/or dried using the gas flow of flue gas. 
   
     
     
         18 . The operating method as claimed in  claim 17 , wherein
 the excess thermal energy is used by first using the flow of flue gas for generating steam, and second using the flow of flue gas for heating the product gas.   
     
     
         19 . The operating method as claimed in  claim 18 , wherein
 cold-blast air is added to the flow of flue gas after using the flow of flue gas for generating steam and before using the flow of flue gas for heating the product gas, and   the cold-blast air is used to adjust a temperature of the flue gas for heating the product gas.   
     
     
         20 . The operating method as claimed in  claim 17 , wherein
 combustion of the heating gas produces sufficient thermal energy to heat the product gas to a reaction temperature required to use the product gas in the upstream plant,   heating of the product gas in the firing device is limited to an intermediate temperature below the reaction temperature, and   the heated product gas is heated up from the intermediate temperature to the reaction temperature by a partial oxidation of the product gas.   
     
     
         21 . The operating method as claimed in  claim 17 , wherein
 combustion of the heating gas is performed with an oxidation gas, and   the excess thermal energy is used to preheat the heating gas and/or the oxidation gas with the flue gas, downstream from the firing device.   
     
     
         22 . The operating method as claimed in  claim 17 , wherein
 the excess thermal energy is used for heating a thermal oil, the thermal oil being heated with the flue gas.   
     
     
         23 . The operating method as claimed in  claim 17 , wherein
 a process gas is produced when removing carbon dioxide and/or water from the export gas, the process gas being enriched with carbon dioxide and water,   a portion of the export gas and/or the process gas is used as the heating gas.   
     
     
         24 . The operating method as claimed in  claim 23 , wherein
 the process gas is used as the heating gas, and   the process gas is mixed with a more combustible gas before being fed to the firing device.   
     
     
         25 . The operating method as claimed in  claim 23 , wherein
 the portion of the export gas and/or the process gas used as the heating gas is buffered in a low-pressure gas accumulator disposed upstream of the firing device.   
     
     
         26 . The operating method as claimed in  claim 17 , wherein
 a top gas accumulates during operation of the upstream plant,   the top gas is combustible, and   the heating gas is formed by mixing respective portions of the top gas and the export gas.   
     
     
         27 . The operating method as claimed in  claim 17 , wherein
 a top gas accumulates during operation of the upstream plant,   the top gas is a hot gas containing thermal energy, and   the thermal energy contained in the top gas is used for steam generation and/or for preheating the product gas before the product gas is supplied to the firing device.   
     
     
         28 . The operating method as claimed in  claim 17 , wherein
 the upstream plant is embodied as a blast furnace, as a smelting reduction plant, as a smelter unit or as a direct reduction plant.   
     
     
         29 . The operating method as claimed in  claim 17 , wherein
 the gas-generating plant is embodied as a coal gasification plant or as a metal smelting plant.   
     
     
         30 . The operating method as claimed in  claim 17 , wherein
 the gas-generating plant is embodied as an iron melting plant or as a smelting reduction plant.   
     
     
         31 . A metallurgical plant comprising:
 a steelmaking plant;   an upstream plant disposed upstream of the steelmaking plant;   a gas-generating plant that generates an export gas;   a separation device to at least partially remove carbon dioxide and/or water from the export gas to thereby generate a product gas;   a firing device connected to the gas-separation device and the upstream plant, to heat the product gas, to produce a heated product gas and to supply the heated product gas to the upstream plant;   a conduit to supply a heating gas to the firing device; and   a conduit to supply and an oxidation gas to the firing device such that combustion of the heating gas and the oxidation gas produces a flow of flue gas,   wherein the metallurgical plant further comprises at least one of:
 an evaporator disposed inside the firing device to generate steam from excess thermal energy produced while heating the product gas, and 
 a raw materials processing device disposed downstream of the firing device in relation to the flow of the flue gas, to preheat and/or dry raw materials that are supplied to the upstream plant and/or to the gas-generating plant. 
   
     
     
         32 . The metallurgical plant as claimed in  claim 31 , further comprising a conduit to supply cold-blast air to the flow of flue gas. 
     
     
         33 . The metallurgical plant as claimed in  claim 31 , wherein
 the separation device produces a process gas enriched in carbon dioxide and water,   the metallurgical plant further comprises a low-pressure gas accumulator to buffer the export gas or the process gas, and   the low-pressure gas accumulator is disposed upstream of the firing device.   
     
     
         34 . The metallurgical plant as claimed in  claim 31 , wherein the upstream plant is a blast furnace, a smelting reduction plant, a smelter unit or a direct reduction plant. 
     
     
         35 . The metallurgical plant as claimed in  claim 31 , wherein the gas-generating plant is a coal gasification plant, a metal smelting plant or a smelting reduction plant. 
     
     
         36 . The metallurgical plant as claimed in  claim 31 , wherein the gas-generating plant is an iron melting plant.