Method for Predicting Carbon Consumption and Carbon Emission of Hydrogen-Rich Blast Furnace (BF) Based on C-rd Theory
20240303751 ยท 2024-09-12
Inventors
- Yana QIE (Tangshan City, CN)
- Qing LYU (Tangshan City, CN)
- Shuhui ZHANG (Tangshan City, CN)
- Ran LIU (Tangshan City, CN)
- Fumin LI (Tangshan City, CN)
- Yanqin SUN (Tangshan City, CN)
- Chenchen LAN (Tangshan City, CN)
- Xiaojie LIU (Tangshan City, CN)
- Jianpeng LI (Tangshan, CN)
Cpc classification
G06F17/18
PHYSICS
International classification
G06Q10/04
PHYSICS
Abstract
The present disclosure provides a method for predicting carbon consumption and carbon emission of a hydrogen-rich blast furnace (BF) based on a C-r.sub.d theory. The method includes: inputting raw material and fuel conditions, product parameters, injection parameters and a heat loss verification coefficient, determining a reduction degree of hydrogen, and establishing a carbon consumption calculation model; determining a direct reduction degree, predicted values of various carbon consumption items and a predicted fuel ratio according to a carbon balance relation; calculating, if an absolute value of a difference between the predicted fuel ratio and an initial fuel ratio is less than a preset value and the various indicators satisfy constraints on the material and heat balance, and outputting the parameter condition and the corresponding calculation results of the various indicators, or otherwise adjusting the initial fuel ratio, heat loss verification coefficient, the raw material and fuel conditions, and the injection parameters.
Claims
1. A method for predicting carbon consumption and carbon emission of a hydrogen-rich blast furnace (BF) based on a C-r.sub.d theory, comprising: inputting raw material and fuel conditions, product parameters, injection parameters and a heat loss verification coefficient of a BF, wherein the raw material and fuel conditions comprise a type of iron ore, a burden structure, an initial fuel ratio, chemical components of a raw material and a fuel, and blast parameters; the blast parameters comprise a blast humidity, a blast temperature, an initial blast volume, an oxygen enrichment rate, and an oxygen (O.sub.2) purity; the product parameters comprise components of molten iron, a temperature of the molten iron, components of slag, a carbon monoxide (CO) utilization rate, components of dust, and a dust volume; and the injection parameters comprise a type of an injected hydrogen-rich medium, an injection amount of the hydrogen-rich medium, an injection temperature, an injection position, and a hydrogen (H.sub.2) utilization rate; determining a reduction degree of hydrogen according to the blast parameters, the initial fuel ratio and the injection parameters; respectively establishing relations of various carbon consumption items of the BF with a direct reduction degree according to the reduction degree of the hydrogen, the raw material and fuel conditions, the product parameters, the injection parameters and the heat loss verification coefficient to obtain a carbon consumption calculation model, wherein the various carbon consumption items comprise carburization of BF molten iron, carbon consumption in direct reduction of trace elements, carbon consumption in direct reduction of iron oxide, carbon consumption in chemical reaction, and carbon consumption for heat supply; and the carbon consumption calculation model comprises a function for calculating an amount of the carburization of the BF molten iron, a function for calculating an amount of the carbon consumption in the direct reduction of the trace elements, a function for calculating an amount of the carbon consumption in the direct reduction of the iron oxide, a function for calculating an amount of the carbon consumption in the chemical reaction, and a function for calculating an amount of the carbon consumption for the heat supply; determining the direct reduction degree according to a carbon balance relation, and determining predicted values of the various carbon consumption items and a predicted fuel ratio according to the direct reduction degree and the carbon consumption calculation model; determining whether an absolute value of a difference between the predicted fuel ratio and the initial fuel ratio is less than a preset value to obtain a first determination result; adjusting, if the first determination result indicates no, the initial fuel ratio and the initial blast volume, and going back to the step of determining a reduction degree of hydrogen according to the blast parameters, the initial fuel ratio and the injection parameters; calculating, if the first determination result indicates yes, a material balance and a heat balance of the BF according to the direct reduction degree, the reduction degree of the hydrogen and the predicted fuel ratio to obtain calculation results of various indicators, wherein the calculation results of the various indicators comprise the predicted values of the various carbon consumption items, carbon emission per ton of iron, the predicted fuel ratio, a raceway adiabatic flame temperature (RAFT) in a tuyere area, a heat loss in a high-temperature area, a temperature of top gas in a low-temperature area, and an overall heat loss of the BF; determining whether the calculation results of the various indicators satisfy constraints on a material balance and a heat balance in each of areas of the BF to obtain a second determination result, wherein the constraints on the material balance and the heat balance in each of the areas of the BF comprise a constraint on a material balance in the tuyere area, a constraint on a heat balance in the tuyere area, a constraint on the RAFT, a constraint on a material balance in the high-temperature area, a constraint on a heat balance in the high-temperature area, a constraint on a material balance in the low-temperature area, a constraint on a heat balance in the low-temperature area, a constraint on a material balance in the whole furnace, and a constraint on a heat balance in the whole furnace; adjusting, if the second determination result indicates no, the heat loss verification coefficient, the raw material and fuel conditions, and the injection parameters, and going back to the step of determining a reduction degree of hydrogen according to the blast parameters, the initial fuel ratio and the injection parameters; and outputting, if the second determination result indicates yes, the raw material and fuel conditions, the product parameters, the injection parameters, the heat loss verification coefficient and the corresponding calculation results of the various indicators, wherein the calculation results of the various indicators are used to evaluate a carbon source, a carbon direction, carbon consumption and carbon emission of the BF.
2. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 1, wherein the function for calculating the amount of the carbon consumption in the chemical reaction is specifically expressed by:
3. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 1, wherein the function for calculating the amount of the carbon consumption for the heat supply is specifically expressed by:
4. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 2, wherein the amount of the carbon reduced to generate the CO.sub.2 is calculated by:
5. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 3, wherein the amount of the carbon combusted in front of the tuyere is calculated by:
6. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 1, wherein the function for calculating the amount of the carbon consumption in the direct reduction of the iron oxide is specifically expressed by:
7. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 1, wherein the carbon balance relation is specifically expressed by:
8. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 1, wherein the predicted fuel ratio is calculated by:
9. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 1, wherein the adjusting the initial fuel ratio and the initial blast volume specifically comprises: updating the initial fuel ratio with a sum of the predicted fuel ratio and the preset value; and determining a predicted blast volume according to a carbon-oxygen balance in front of a tuyere, and updating the initial blast volume with the predicted blast volume, wherein the predicted blast volume is calculated by:
10. The method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory according to claim 1, after the respectively establishing relations of various carbon consumption items of the BF with a direct reduction degree according to the reduction degree of the hydrogen, the raw material and fuel conditions, the product parameters, the injection parameters and the heat loss verification coefficient to obtain a carbon consumption calculation model, further comprising: drawing and outputting a carbon consumption line distribution diagram according to the carbon consumption calculation model.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] To describe the technical solutions in the examples of the present disclosure or in the prior art more clearly, the accompanying drawings required for the examples are briefly described below. Apparently, the accompanying drawings in the following description show merely some examples of the present disclosure, and those of ordinary skill in the art may still derive other accompanying drawings from these accompanying drawings without creative efforts.
[0049]
[0050]
[0051]
[0052]
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0053] The technical solutions of the embodiments of the present disclosure are clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.
[0054] An objective of the present disclosure is to provide a method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory, so as to obtain relations of operation parameters in different hydrogen enrichment processes with carbon consumption and carbon emission of the BF, predict and evaluate carbon consumption and carbon emission of the different hydrogen enrichment processes, and elaborate a carbon source, a carbon direction, carbon consumption and carbon emission in the operation parameters of the different hydrogen enrichment processes, thereby providing theoretical guidance for hydrogen enrichment of the BF and low-carbon energy transformation of the BF.
[0055] The present disclosure uses the following technical solutions: According to a principle of a C-r.sub.d relation proposed by A. H. Ramm (namely a C-r.sub.d theory), and in view of influences of hydrogen, linear relations of carbon consumption items in a BF with a direct reduction degree r.sub.d are established. The carbon consumption items in the BF include carburization of molten iron, carbon consumption in reduction of trace elements, carbon consumption in direct reduction of iron, carbon consumption in indirect reduction, and carbon consumption for heat supply. The relations of the various carbon consumption items with the r.sub.d are calculated. Loop iteration is carried out according to a carbon balance relation to obtain the r.sub.d, r.sub.H.sub.
[0056] To make the above objectives, features, and advantages of the present disclosure clearer and more comprehensible, the present disclosure will be further described in detail below with reference to the accompanying drawings and the specific implementations.
[0057] As shown in
[0061] Specifically, according to the raw material and fuel conditions (namely raw material conditions and fuel conditions) of the BF and product requirements, relations of the carburization of the BF molten iron, the carbon consumption in the direct reduction of the trace elements, the carbon consumption in the direct reduction of the iron oxide, the carbon consumption in the chemical reaction and the carbon consumption for the heat supply with the direct reduction degree are established. The relation of each carbon consumption item C and the direct reduction degree r.sub.d is calculated as follows: [0062] (1) The amount w(C).sub.carurtization of the carburization of the molten iron:
[0063] where, t is the temperature of the molten iron; w[Mn], w[Si], w[P] and w[S] are respectively contents of elements in the molten iron by a mass percent; 2.54, 0.04, 0.3, 0.35 and 0.4 are respectively relational coefficients of the amount of the carburization with the temperature, w[Mn], w[Si], w[P], and w[S] in the molten iron. [0064] (2) The amount w(C).sub.Si,Mn,P of the carbon consumption in the direct reduction of the trace elements:
[0065] where, 12/28?2, 12/56 and 60/62 are respectively masses of carbon consumed to reduce 1 mol of [Si], 1 mol of [Mn] and 1 mol of [P]. [0066] (3) The amount w(C).sub.d of the carbon consumption in the direct reduction of the iron oxide:
[0067] where, r.sub.d is the direct reduction degree defined by the Pavlov, and specifically refers to a direct reduction degree of [Fe]. [0068] (4) The amount of the carbon consumption in the chemical reaction, namely an amount w(C).sub.i of carbon consumption in indirect reduction of the iron oxide:
[0069] where, r.sub.H.sub.
[0071] where, w(C) is the amount of the carbon consumption for the heat supply, and w(C).sub.combustion is an amount of carbon combusted in front of a tuyere and may be calculated through a second heat balance of the BF, namely ?.sub.i Q.sub.heatsupply.sub.
[0072] where, q.sub.CO is heat that 1 kg of carbon is combusted in front of the tuyere to generate CO; q.sub.hot blast heat carried in by hot-blast air required to combust 1 kg of carbon; Q.sub.injection is physical heat carried by the injected hydrogen-rich medium, which is associated with the injection amount of the hydrogen-rich medium and the injection temperature, and calculated by Eq. (9); Q.sub.others is other heat of the BF, such as heat carried in by hot charging of the raw material of the BF; Q.sub.reduction is heat consumed by reduction, which is associated with the direct reduction degree, the reduction degree of the hydrogen and the components of the molten iron, and calculated by Eq. (10); Q.sub.molten iron is heat carried off by the molten iron; Q.sub.slag is heat carried off by the slag; Q.sub.top gas is heat carried off by top gas, which is associated with components and a temperature of the top gas and calculated by Eq. (11), the components of the top gas depending on the direct reduction degree and the reduction degree of the hydrogen;
is heat consumed by cracking of H.sub.2O in front of the tuyere; Q.sub.heat loss is a heat loss, which is specifically 5-10% of total heat; Q.sub.cracking of pulverized coal is heat consumed by cracking of pulverized coal in front of the tuyere;
is heat carried off by evaporation of H.sub.2O in the raw material and the fuel of the BF; and Q is the heat loss verification coefficient. As can be seen, except that Q.sub.reduction and Q.sub.top gas are associated with the direct reduction degree and the reduction degree of the hydrogen, other items can be solved by the raw material and fuel conditions of the BF, the product parameters and the injection parameters to obtain specific values. The reduction degree of the hydrogen can also be obtained by Eq. (6). Hence, a relation between w(C).sub.combustion and the direct reduction degree r.sub.d can be established, and substituted into Eq. (7) to obtain a relation between w(C) and the r.sub.d.
[0073] where, T.sub.injection is the injection temperature, i is the injected hydrogen-rich medium, and c.sub.P,i is a molar heat capacity at a constant pressure for the injected hydrogen-rich medium i.
[0074] where, k denotes different reduction items; Q.sub.direct reduction is heat consumed by the direct reduction of the iron oxide, Q.sub.indirect reduction is heat consumed by the indirect reduction of the iron oxide, and Q.sub.Si,Mn,P is heat consumed by the reduction of the trace elements, at a unit of kJ/tFe; w.sub.silicate is a mass of SiO.sub.2 in an iron bearing material, w.sub.Fe.sub.
[0075] where, Q.sub.CO.sub.
respectively heat carried off by CO.sub.2, CO, N.sub.2, H.sub.2 and H.sub.2O in the top gas, at a unit of kJ/tFe; q.sub.CO.sub.
are respectively heat carried off by 1 mol of CO.sub.2, 1 mol of CO, 1 mol of N.sub.2, 1 mol of H.sub.2 and 1 mol of H.sub.2O in the top gas, at a unit of kJ/mol, and calculated by Eq. (12); V.sub.b is the initial blast volume; and (N.sub.2).sub.b is a volume fraction of N.sub.2 in the blast air.
[0076] where, j is a component of the top gas, mainly including CO.sub.2, CO, N.sub.2, H.sub.2 and H.sub.2O, c.sub.P,j is a molar heat capacity at a constant pressure for the component j, for example: c.sub.P,O.sub.
[0077] After the relations of the various carbon consumption items with the direct reduction degree are established, the carbon consumption calculation model is obtained. When the direct reduction degree is within [0, 1?r.sub.H.sub.
[0079] The carbon balance relation is specifically expressed by:
[0080] where, w(C).sub.i is the amount of the carbon consumption in the chemical reaction, C.sub.injection is an equivalent amount of carbon carried in by the injected hydrogen-rich medium, w(C) is the amount of the carbon consumption for the heat supply, w(C).sub.carburization is the amount of the carburization of the BF molten iron, and w(C).sub.Si,Mn,P is the amount of the carbon consumption in the direct reduction of the trace elements.
[0081] Specifically, according to the carbon balance relation, equations for calculating C.sub.injection, w(C), w(C).sub.carburization and w(C).sub.Si,Mn,P are substituted into Eq. (13), namely Eqs. (1)-(12) are substituted into Eq. (13). On two sides of the resulting equation, only r.sub.d is unknown. Solving the equation obtains the direct reduction degree r.sub.d. The r.sub.d is brought back to the carbon consumption calculation model, thereby obtaining the various carbon consumption items of the BF.
[0082] According to the carbon-oxygen balance in front of the tuyere, the predicted fuel ratio is calculated by:
[0083] where, K is the predicted fuel ratio, and w(C).sub.k is a mass percent of carbon in the fuel. [0084] Step S5: Determine whether an absolute value of a difference between the predicted fuel ratio and the initial fuel ratio is less than a preset value to obtain a first determination result. Preferably, the preset value is 0.2. [0085] Step S6: Adjust, if the first determination result indicates no, the initial fuel ratio and the initial blast volume, and go back to Step S2.
[0086] Specifically, the initial fuel ratio is updated with a sum of the predicted fuel ratio and the set value. According to the carbon-oxygen balance in front of the tuyere, a predicted blast volume is determined, and the initial blast volume is updated with the predicted blast volume. [0087] Step S7: Calculate, if the first determination result indicates yes, a material balance and a heat balance of the BF according to the direct reduction degree, the reduction degree of the hydrogen and the predicted fuel ratio to obtain calculation results of various indicators, where the calculation results of the various indicators include the predicted values of the various carbon consumption items, carbon emission per ton of iron, the predicted fuel ratio, an RAFT in a tuyere area, a heat loss in a high-temperature area, a temperature of top gas in a low-temperature area, and an overall heat loss of the BF. Generally, the temperature of 900-1,000? C. in the BF is used as a boundary between the high-temperature area and the low-temperature area. The high-temperature area refers to an area with a temperature higher than the boundary, and the low-temperature area refers to an area with a temperature lower than the boundary.
[0088] In addition, according to the actual production requirements, the calculation results of the various indicators may further include a distribution of the reduction degree, a coal generation process, a heat balance sheet in the high-temperature area, a heat balance sheet in the low-temperature area, and an overall heat balance sheet and an overall material balance sheet of the BF. Based on the calculation results of the various indicators, the present disclosure can further be used to analyze trends of the various indicators under different hydrogen enrichment conditions to obtain adjustment directions. [0089] Step S8: Determine whether the calculation results of the various indicators satisfy constraints on a material balance and a heat balance in each of areas of the BF to obtain a second determination result, where the constraints on the material balance and the heat balance in each of the areas of the BF include a constraint on a material balance in the tuyere area, a constraint on a heat balance in the tuyere area, a constraint on the RAFT, a constraint on a material balance in the high-temperature area, a constraint on a heat balance in the high-temperature area, a constraint on a material balance in the low-temperature area, a constraint on a heat balance in the low-temperature area, a constraint on a material balance in the whole furnace, and a constraint on a heat balance in the whole furnace. [0090] Step S9: Adjust, if the second determination result indicates no, the heat loss verification coefficient, the raw material and fuel conditions, and the injection parameters, and go back to Step S2. [0091] Step S10: Output, if the second determination result indicates yes, the raw material and fuel conditions, the product parameters, the injection parameters, the heat loss verification coefficient and the corresponding calculation results of the various indicators, where the calculation results of the various indicators are used to evaluate a carbon source, a carbon direction, carbon consumption and carbon emission of the BF.
[0092] Specifically, the r.sub.d, r.sub.H2 and various carbon consumption values are substituted into calculation of the material balance and the heat balance in each of the areas of the BF to observe whether the constraints on the RAFT, the high-temperature area, the low-temperature area, the heat balance in the whole furnace and the like are satisfied. If yes, the results are output. If no, the heat loss verification coefficient in the function for calculating the amount of the carbon consumption for the heat supply is adjusted, and the input raw material and fuel conditions and injection parameters are adjusted, until the constraints are satisfied. It is to be noted that upon adjustment, the heat loss accounts for 5-10% of total heat.
[0093] Further, after the step of respectively establishing relations of various carbon consumption items of the BF with a direct reduction degree according to the reduction degree of the hydrogen, the raw material and fuel conditions, the product parameters, the injection parameters and the heat loss verification coefficient to obtain a carbon consumption calculation model, the method further includes: Draw and output a carbon consumption line distribution diagram according to the carbon consumption calculation model. From the carbon consumption line distribution diagram, the carbon source and the carbon direction can be directly known.
[0094] Specific examples are provided hereinafter to verify correctness of the method.
[0095] Example 1: Relations between various carbon consumption items C of the hydrogen-rich BF and r.sub.d are established, and intersections are obtained, thereby verifying the calculation method.
[0096] Production parameters from a BF in China are used as an initial condition for calculation. The BF has a CO utilization rate of 50%, thus obtaining the carbon consumption w(C).sub.i=w(C).sub.?CO=0.5=1/0.5*w(C).sub.CO.sub.
[0097] Example 2: The coal injection is changed into single COG injection to predict influences of hydrogen enrichment with the single COG injection on carbon consumption of the BF.
[0098] 300 m.sup.3/tHM COG at 25? C. is used as an injection condition. Through calculation of the model, the C-r.sub.d line distribution is as shown in
[0099] Example 3: The coal injection is changed into hybrid injection of coal and COG to predict influences of hydrogen enrichment with the hybrid injection of the coal and the COG on carbon consumption of the BF.
[0100] By fixing the coal injection rate at 167 kg/tFe, carbon consumption line distribution of the BF with the hybrid injection of the coal and the COG is as shown in
[0101] Example 4: While the constraints on the material balance and the heat balance in each of the areas of the BF are satisfied, energy conservation and carbon emission effects of different hydrogen enrichment processes that are predicted with the method for predicting carbon consumption and carbon emission of a hydrogen-rich BF based on a C-r.sub.d theory are as shown in Table 1. As compared with results of the BF from foreign hydrogen-enrichment test, the present disclosure is reasonable and reliable.
TABLE-US-00001 TABLE 1 Comparison of different hydrogen enrichment processes in energy conservation and carbon emission Injection amount Coke ratio CO.sub.2 emission Comparison at Condition per ton of iron kg/tFe RAFT ? C. reduction % home and abroad Coal injection 167 kg/tFe 358 2134 1% BF in China Single COG 119 2101 3% Japanese COURSE50 injection Nm.sup.3/tFe project Single COG 119 2097 3.17%.sup. Present disclosure injection Nm.sup.3/tFe Single H.sub.2 310 2091 12% Japanese COURSE50 injection Nm.sup.3/tFe project Single H.sub.2 310 2082 11% Present disclosure injection Nm.sup.3/tFe Top Circulation volume 273 1852 22.67% Present disclosure gas-gas-making 775 furnace-BF top Nm.sup.3/tFe gas circulation Injection of coal + 167 kg/tFe of coal + 305-280 1900 0-5% Present disclosure COG 132.5-357.5 Nm.sup.3/tFe of COG Injection of coal + 167 kg/tFe of coal 316-300 1900 9%-13% Present disclosure H.sub.2 167-500 Nm.sup.3/tFe of H.sub.2 Injection of coal + 167 kg/tFe of coal + 272-182 1900 19.5%-39.7% Present disclosure 1200? C. H.sub.2 295-800 Nm.sup.3/tFe of H.sub.2
[0102] Each example of the present disclosure is described in a progressive manner, each example focuses on the difference from other examples, and the same and similar parts between the examples may refer to each other.
[0103] Specific examples are used herein to explain the principles and embodiments of the present disclosure. The foregoing description of the embodiments is merely intended to help understand the method of the present disclosure and its core ideas; besides, various modifications may be made by those of ordinary skill in the art to specific embodiments and the scope of application in accordance with the ideas of the present disclosure. In conclusion, the content of the present specification shall not be construed as limitations to the present disclosure.