Method for operating a steelworks

Abstract

The invention relates to a method for operating a steelworks, for example in a blast furnace converter route, or with a direct reduction of iron ore with hydrogen with downstream electrical steel route, preferably additionally a secondary steel route. To carry out the method, the following are balanced: A) a number of starting material flows of supplied starting materials, B) a number of by-product material flows from emitted by-products, and C) a number of energy flows of used energy.

1 . Method for operating a steelworks,
 wherein   in particular a method   a) of the blast furnace converter route, or   b) of direct reduction of iron ore with hydrogen with a downstream electric steel route—preferably also a secondary steel route—   is used,   wherein the method is carried out by supplying starting materials and using energy in order to obtain intermediate products and, finally, steel as a product in a number of successive method steps under the emission of accompanying products,   wherein, to carry out the method,   A) a number of starting material flows of supplied starting materials,   B) a number of accompanying product material flows of emitted accompanying products, and   C) a number of energy flows of energy used   are balanced,   wherein a CO2 footprint value is determined for each starting material flow, accompanying product material flow, and energy flow under consideration,   wherein a CO2 footprint initial value is determined in each case for each starting material flow and for each energy flow,   wherein a CO2 footprint connection value is determined in each case for each accompanying product material flow,   and wherein a total CO2 balance value is formed from the CO2 footprint values,   wherein the CO2 footprint values and the total CO2 balance value are continuously updated,   wherein, if the total CO2 balance value exceeds a predetermined CO2 footprint threshold value,   the supply of starting materials and/or   the energy supply is adjusted to reduce the CO2 footprint value below the CO2 footprint threshold value.   
     
     
         2 . Method according to  claim 1 , wherein the blast furnace converter route is used,
 wherein, to carry out the method,   A) at least the starting materials of iron ore, coke, and air are supplied in a blast furnace method step, and at least the starting materials of calcium oxide and oxygen are supplied in a converter method step,   B) at least CO2 and slag are emitted as the accompanying product material flow,   C) electrical energy is used to operate the plant,   wherein the CO2 footprint initial value is determined for each starting material flow and energy flow,   wherein the CO2 footprint initial values of the starting materials are determined on the basis of database data or on the basis of values provided by the supplier,   wherein the CO2 footprint connection value of the accompanying product material flow for the accompanying material of CO2 is measured by a CO2 measuring device by measuring the amount of CO2 emitted, or the measurement of a change in the amount of CO2 emitted,   wherein a calculation of the CO2 footprint connection value of the accompanying product material flow is carried out at least for slag, taking into account the further use of the slag,   wherein the total CO2 balance value is determined summarily from the CO2 footprint initial values and the CO2 footprint connection values,   wherein, if the total CO2 balance value exceeds the predetermined threshold, the energy supply is switched to the use of renewably produced energy and/or equivalent starting materials with different initial CO2 footprint values are temporarily stored, e.g., on the steelworks site, and, if the total CO2 balance value exceeds the predetermined threshold, a selection of a starting material with a higher initial CO2 footprint value for supply to the blast furnace converter route is changed to a selection of a starting material with a lower initial CO2 footprint value for supply to the blast furnace converter route.   
     
     
         3 . Method according to  claim 2 , wherein, for one or more of the starting materials, the addition of the starting material is measured
 by measuring the weight of the added starting material, or   by measuring a volume flow of the added starting material, or,   for an energy flow, by measuring a working quantity of the energy flow,   and the CO2 footprint values and the total CO2 balance value are continuously updated with the measured values.   
     
     
         4 . Method according to  claim 2 , wherein
 one or more of the following starting materials is also supplied in the blast furnace method step:   i) natural gas,   ii) H2,   iii) methane,   wherein the proportion of natural gas and/or the proportion of H2 in the starting material flow is increased if the total CO2 balance value exceeds a predetermined CO2 footprint threshold value, and/or   wherein the proportion of H2 or methane from biogas production or pyrolysis of renewable starting materials or synthesis gas from biomass in the aggregate of the gases mentioned above under i), ii), and iii) is increased if the total CO2 balance value exceeds a second CO2 footprint threshold value which is greater than the CO2 footprint threshold value.   
     
     
         5 . Method according to one of  claim 2 , wherein the blast furnace converter route of one or more of the following measuring devices has:
 a scale, elemental analyzers (CHNS-O and/or FOES and/or ICP-OES), DCP, IR, density measurement, Wobbe index, GCMS, bomb calorimeter, conductivity meters, current meters, current-voltage meters, gas volume meters, thermometers, viscosity meters, ignition loss meters, moisture meters, C-content meters for all aggregate states.   
     
     
         6 . Method according to  claim 1 , wherein the direct reduction of iron ore with hydrogen is used with a downstream electric steel route,
 wherein, to carry out the method,   A) at least the starting materials of iron ore and at least one of the starting materials of H2 or methane or natural gas or another carbon-containing gas are added to a direct reduction plant for the production of sponge iron,   B) at least CO2, is emitted as the accompanying product material flow,   C) electrical energy is used to operate the plant,   wherein the CO2 footprint initial value is determined for each starting material flow and energy flow,   wherein the CO2 footprint initial values of the starting materials are determined on the basis of database data or values provided by the supplier,   wherein the CO2 footprint connection value of the accompanying product material flow for the accompanying material of CO2 is measured by a CO2 measuring device by measuring the amount of CO2 emitted, and preferably also other carbon compounds such as at least CO and/or CH4, or the measurement of a change in the amount of CO2 emitted,   wherein the total CO2 balance value is determined summarily from the CO2 footprint initial values and the CO2 footprint connection values,   wherein,   if the total CO2 balance value exceeds the predetermined threshold, the energy supply is switched to the use of renewably produced energy, and/or   equivalent starting materials with different CO2 footprint initial values are temporarily stored, e.g., on the steelworks site, and, if the total CO2 balance value exceeds the predetermined threshold, a selection of a starting material with a higher CO2 footprint initial value for supply to the direct reduction plant or at another input point of the production route is changed to a selection of a starting material with a lower CO2 footprint initial value for supply to the production route, and/or,   if the total CO2 balance value falls below the predetermined threshold by a minimum margin, the production of sponge iron is stopped in step A, and the addition of temporarily stored direct reduced iron is started, and, if the total CO2 balance value exceeds the predetermined threshold again, the addition of temporarily stored direct reduced iron is stopped, and the production of sponge iron is started in step A).   
     
     
         7 . Method according to  claim 6 , wherein, for one or more of the starting materials, the addition of the starting material is measured
 by measuring the weight of the added starting material, or   by measuring a volume flow of the added starting material, or,   for an energy flow, by measuring a working quantity of the energy flow,   and the CO2 footprint values and the total CO2 balance value are continuously updated with the measured values.   
     
     
         8 . Method according to  claim 1 , wherein, for the total CO2 balance value, the following applies:
 a) for crude steel from primary steel production, <2,050 kg CO2 eq, and/or,   b) for crude steel from secondary steel production, <400 kg Co2 eq, and/or,   c) for a mixture, a value resulting from a) and b).   
     
     
         9 . Method according to  claim 3 , wherein
 one or more of the following starting materials is also supplied in the blast furnace method step:   i) natural gas,   ii) H2,   iii) methane,   wherein the proportion of natural gas and/or the proportion of H2 in the starting material flow is increased if the total CO2 balance value exceeds a predetermined CO2 footprint threshold value, and/or   wherein the proportion of H2 or methane from biogas production or pyrolysis of renewable starting materials or synthesis gas from biomass in the aggregate of the gases mentioned above under i), ii), and iii) is increased if the total CO2 balance value exceeds a second CO2 footprint threshold value which is greater than the CO2 footprint threshold value.   
     
     
         10 . Method according to one of  claim 3 , wherein the blast furnace converter route of one or more of the following measuring devices has:
 a scale, elemental analyzers (CHNS-O and/or FOES and/or ICP-OES), DCP, IR, density measurement, Wobbe index, GCMS, bomb calorimeter, conductivity meters, current meters, current-voltage meters, gas volume meters, thermometers, viscosity meters, ignition loss meters, moisture meters, C-content meters for all aggregate states.   
     
     
         11 . Method according to one of  claim 4 , wherein the blast furnace converter route of one or more of the following measuring devices has:
 a scale, elemental analyzers (CHNS-O and/or FOES and/or ICP-OES), DCP, IR, density measurement, Wobbe index, GCMS, bomb calorimeter, conductivity meters, current meters, current-voltage meters, gas volume meters, thermometers, viscosity meters, ignition loss meters, moisture meters, C-content meters for all aggregate states.