Overview of Research Characteristics
Through the analysis of the basic characteristics of carbon emission research in the steel industry, the development of the research in this field can be grasped as a whole, and the academic circles' attention to this field and its research value can be understood.
Research Records Distribution
Through sorted out the published papers from 1991 to 2020, it is found that the distribution of the published papers related to carbon emissions in the iron and steel industry showed an overall increasing trend. As shown in Figure 1 below, some researchers began to pay attention to carbon emissions in the steel industry in the early 1990s, and corresponding research results emerged. In recent years, it has attracted widespread attention. In 1991, Italian scholar Gretz, J, et al first made relevant research in this field and put forward their opinions, and they thought that steel production is one of the most important source of carbon dioxide pollution, as a large user of coal and other forms of energy, in order to cope with the threat of global warming, it is necessary to control coal consumption and seek alternative energy (Gretz et al. 1991).Perhaps because its early research mode is still in the initial stage of exploration, the active promotion of practical actions has not triggered a strong academic boom, and the research on carbon emissions in the steel industry has not been widely paid attention by scholars from all walks of life. This continued until the early 2000s, after which the number of discoveries in the field began to increase. Especially in 2020, the annual number of published papers on carbon emissions research in the steel industry reached a peak of 69. The proposed idea of carbon peak and carbon neutral goal (Chen 2020) made scholars and research institutions around the world paid more attention to this research field, and a large number of new theories, new methods and new technologies continued to emerge, and the number of published papers grows rapidly.
Analysis of the Major Sources
The continuous development and growth of carbon emission research in the steel industry in the past 30 years has benefited from the continuous support of international journals of various disciplines. Table 1 lists the journals that published more than 4 research articles in this field, including energy, environmental engineering, metallurgy and ecology, etc., with strong comprehensive disciplines. More than half of the major source journals are in JCR 1 area, among which the number of publications of Energy is the highest with an impact factor above 6. Other top six journals, such as Energy Policy and Journal of Cleaner Production, all have an impact factor above 7. The most prominent one is that the 5-year impact factor of Applied Energy has reached 9.086. This indicated that the carbon emission research of iron and steel industry has been widely concerned by the mainstream academic journals, especially the authoritative energy journals. Thus it can be seen that although the carbon emission research field of the steel industry started late, with the increasingly severe global climate change situation (Isson et al. 2020), scholars and authoritative professional journals from all walks of life are gradually paying more attention to it.
Table 1Journals with more than 4 papers on carbon emission research in the steel industry
Source journal name
|
Number of papers/ article
|
Percentage/%
|
Impact factor (2019)
|
5-year impact factor
|
Energy
|
16
|
13.8
|
6.082
|
6.046
|
Energy Policy
|
14
|
12.1
|
5.042
|
5.693
|
Journal of Cleaner Production
|
10
|
8.6
|
7.246
|
7.491
|
Resources Conservation and Recycling
|
9
|
7.8
|
8.086
|
7.589
|
Applied Energy
|
6
|
5.2
|
8.848
|
9.086
|
Environmental Science & Technology
|
6
|
5.2
|
7.864
|
8.543
|
International Journal of Greenhouse Gas Control
|
6
|
5.2
|
3.639
|
3.698
|
Sustainability
|
6
|
5.2
|
2.576
|
2.798
|
Energies
|
5
|
4.3
|
2.702
|
2.822
|
Journal of Iron and Steel Research International
|
5
|
4.3
|
1.213
|
1.357
|
Steel Research International
|
5
|
4
|
1.81
|
1.769
|
Analysis of Main Research Forces and Cooperation
In order to have a deeper understanding of the specific research situation in the field of carbon emissions in the steel industry, this part made a bibliometric and statistical analysis on the major publishing regions, publishing institutions and high-yield authors, and explored the internal relationship between the literatures in this field.
Analysis of Main Publishing Countries and Regions
In order to explore the cooperation characteristics of publishing countries in the carbon emission research of the steel industry, CiteSpace software was used to conduct a quantitative analysis of the literature extracted from SCIE. Country was selected in the Node Type and the distribution network map of publishing countries and regions was obtained as shown in Figure 2 below. After statistics, it is found that a total of 41 countries and regions have published relevant literatures (due to the small nodes in some regions with a small number of published papers, they are not shown in the figure), mainly distributed in Asia, Europe, Oceania and North America. The top ten countries and regions were sorted out. As shown in Figure 3, all countries except China are developed countries, which also echoes the economic and cultural development pattern of the world today.
The size of the node (circle) in the network map of the country and region where the paper is issued represents the amount of the paper it publishes and the size of nodes means the number of articles it publishes. In addition, the thickness of the connection lines indicates the degree of cooperation. In the picture, we can see obviously, China has the largest number of nodes. It is the only country that has published more than 100 papers on carbon emissions in the steel industry, up to 157 papers, and it is the core force of research in this field. As the world's largest energy user in the steel industry and one of the major industrial CO2 emitters, China has increasingly strict requirements for carbon emission reduction in recent years, and relevant scholars have paid more and more attention to the research in this field (Peng et al. 2018). At the same time, the major publishing countries and regions have formed a close cooperation network with China, the United States, the United Kingdom and Japan as the core, including Germany, Sweden, Australia, Finland, the Netherlands and Italy. Except for China, the key scientific research force of carbon emission research of the steel industry mainly comes from western countries, led by the United States. The cause of the phenomenon may have two aspects, on the one hand, because of the steel industry carbon emissions research is by the European scholars Gretz, J., AKIMOTO, H and SUZUKI, M and others take the lead in put forward and carry out related research (Gretz et al.1994; Akimoto and Narita 1994; Suzuki et al. 1995);On the other hand, due to the limited level of industrial development and weak scientific research strength in Africa, South Asia and Southeast Asia, etc., they do not pay much attention to this field (Abdelaziz et al. 2017).
Analysis of Major Publishing Research Institutions
By sorting out the statistics of the international research institutions in the field of carbon emissions in the steel industry, the top 20 research institutions are listed as shown in Table 2 below. Among them, Chinese Academy of Sciences (Chinese AcadSci) published the highest number of papers, with 26 papers. The first paper in this field was published in 2007. Through the decomposition method of Malmquist index, Wei, Y. M., et al. found that due to the technological progress and improvement of technical efficiency, the energy efficiency of China's iron and steel industry increased by 60% from 1994 to 2003, which greatly reduced the carbon emissions of the steel industry (Wei et al. 2007).Secondly, the number of published papers of research institutions in the United States, Sweden, the United Kingdom and Australia follow closely, and most of them are national universities and colleges.This indicates that a large proportion of the scientific research force is stored in higher education institutions. Although this can make use of the best academic advantages to promote the development of carbon emission research in the steel industry, at the same time, other research institutions should be actively encouraged to join in this field to continuously expand the depth and breadth of research in this field.
Table 2Top 20 scientific research institutions of carbon emission research in iron and steel industry
Issuing organization
|
Number of papers / article
|
Start year
|
Chinese AcadSci
|
26
|
2007
|
Xiamen Univ
|
15
|
2016
|
Northeastern Univ
|
13
|
2011
|
Chalmers Univ Technol
|
12
|
2013
|
Tsinghua Univ
|
12
|
2006
|
Univ Chinese AcadSci
|
11
|
2014
|
Jiangxi Univ Finance & Econ
|
8
|
2016
|
Univ Sci & Technol Beijing
|
7
|
2017
|
Lawrence Berkeley Natl Lab
|
6
|
2002
|
Lulea Univ Technol
|
6
|
2007
|
NatlInstEnvironm Studies
|
5
|
2003
|
Univ Cambridge
|
5
|
2010
|
China UnivGeosci
|
5
|
2011
|
Beijing Normal Univ
|
5
|
2012
|
Beijing Inst Technol
|
5
|
2009
|
CSIRO
|
4
|
2011
|
JFE Steel Crop
|
4
|
2006
|
Natl Cheng Kung Univ
|
4
|
2007
|
UnivNaclAutonoma Mexico
|
4
|
2002
|
Abo AkadUniv
|
4
|
2010
|
In addition, this paper uses CiteSpacebibliometric software to generate a network map of research institutions of carbon emission in the steel industry (Fig.4), which can indicate the cooperation between major publishing institutions and further explore the distribution of scientific research forces in this field. In the network graph, nodes represent the number of articles published by research institutions, and the connecting lines between nodes represent the degree of cooperation among research institutions. As can be seen from Figure 4, on the whole, there is a certain degree of cooperation among major scientific research institutions, and the closely connected scientific research institutions are geographically close to each other. For example, China and Japan in Asia, the United States and Mexico in the Americas and other countries and regions have close cooperative relations. Only some underdeveloped countries and regions have weak cooperative relations between their research institutions.
Analysis of Main High-yield Authors
In this paper, the authors of carbon emissions research in the steel industry are sorted out and summarized, and the number of published papers, nationality, institution and research scope keywords of the top 10 most productive authors in this field are statistically analyzed, as shown in Table 3 below.It is intuitive to find that nearly half of these major prolific authors are from China, led by Professor Lin Boqiang of Xiamen University. Professor Lin Boqiang had published 14 papers in total. He has made a key contribution to the research on industrial energy conservation and carbon emission reduction in China and represents the forefront of scientific research and development in this field in China (Lin et al. 2017; Lin and Xu 2018; Lin and Xu 2018).At the present stage, China is experiencing rapid industrialization and urbanization, resulting in a sharp increase in energy demand (Xu and Lin 2016).He emphasized that in the context of energy shortage, environmental pollution and energy cost constraints, energy conservation and emission reduction in the steel industry will become an important strategy for China's transformation to a low carbon economy (Lin and Du 2017).He was followed by FilipJohnsson of Chalmer s University of Technology in Sweden with nine and Johan Rootzen of the University of Gothenburg with five. FilipJohnsson, Johan Rootzen and Professor Lin differ in their geographical scope due to differences in nationality, but their research aims are similar. In the Paris Agreement, Sweden promised to reduce greenhouse gas (GHG) emissions to zero by 2045 (Karlsson et al. 2020). FilipJohnsson and Johan Rootzen expected to achieve substantial emission reductions in energy-intensive industries through carbon capture and storage, so as to fulfill the commitment and achieve sustainable development goals (Johnsson et al. 2020;Johnsson et al. 2020).
Table 3Top 10 authors of carbon emission research in iron and steel industry
Author
|
Number of papers/article
|
Nationality
|
Organization
|
Research keywords
|
Boqianglin
|
14
|
China
|
Xiamen University
|
Energy economy; Energy policy; Technical economy, etc
|
Bin Xu
|
9
|
China
|
Jiangxi University of Finance and Economics
|
Steel industry; Carbon dioxide emissions; Panel data model, etc
|
FilipJohnsson
|
9
|
Sweden
|
Chalmers University of Technology
|
Carbon capture; Industrial CCS; Economic analysis, etc
|
Johan Rootzen
|
5
|
Sweden
|
University of Gothenburg
|
Carbon emission reduction; Climate change impact; Low carbon technology; Sustainable transformation; Scenario analysis, etc
|
E Worrell
|
4
|
U.S.A
|
Lawrence Berkeley National Laboratory
|
Steel industry; Carbon emission reduction; Energy efficiency, etc
|
Ida Karlsson
|
4
|
Sweden
|
Chalmers University of Technology
|
Carbon emission reduction; Greenhouse gas emissions; Sustainable transformation; Value chain; Supply chain, etc
|
Ali Hasanbeigi
|
4
|
Norway
|
Southeast University of Norway
|
MEA; Steelmaking; CCS; Cost estimation, etc
|
Yong Geng
|
4
|
China
|
Shanghai Jiaotong University
|
Iron and steel industry; Environmental economic model; Technology upgrading; Carbon trading, etc
|
Guibing Hong
|
4
|
Taiwan, China
|
Taipei University of Technology
|
Iron and steel industry; Construction industry; Taiwan; Energy saving; Energy audit, etc
|
RenjingXu
|
3
|
China
|
Nanchang Institute of Technology
|
Iron and steel industry; Carbon dioxide emissions; Quantile Regression, etc
|
In addition, several collaboration groups of authors have been formed in the field of carbon emission research in the steel industry, among which the collaboration among the highly productive authors is more prominent. In order to more intuitively represent the cooperation system among scholars, this paper usedCiteSpace software to generate a map of author cooperation network (Fig.5) for analysis. It can be seen from this map that only a few scholars have formed a cooperative network, among which the most extensive group is centered on E Worrell of Lawrence Berkeley National Laboratory, including L Price and N Martin, etc. They looked at the low cost energy efficiency and carbon reduction opportunities in the US steel industry (Worrell et al. 2001). The most closely collaborated group is Lin Boqiang and Xu Bin. They identified the key influencing factors of carbon dioxide emissions in China's steel industry from the perspective of regional geographical differences, and provided certain theoretical support and practical guidance for realizing carbon emission reduction in China's iron and steel industry and formulating effective environmental protection measures (Xu et al. 2017; Xu and Lin 2018).
Hot Spots and Cutting-edge Analysis
Through keyword co-occurrence, clustering and Timezone analysis of literature data, we can better grasp the hot topics and research frontiers in the field of carbon emissions in iron and steel industry, and clarify its development vein and future research direction.
Keywords Co-occurrence Analysis
Keywords are the words that express the concept of the central theme of a literature, and the keywords cited jointly by multiple scientific literatures are keyword co-occurrence. It can show the correlation between the research keywords of carbon emissions in the steel industry very intuitively, and can also explore the research focus and hotspots by observing the word frequency and centrality ranking (Shi and Li 2019). A research hotspot is generally defined as a key topic jointly discussed by closely related scientific literatures in a certain period of time. It is a representative vocabulary to describe the core content of an article, and the frequently co-occurring keywords reflect the hot topic of the research (Li and Chen 2018).
Running CiteSpace, set Node Type as Keyword, and the time range was 1991-2020, the network cutting method was Pathfinder, Pruning networks and Pruning the merged network, selected 1 year time slice, selected keywords for Node Type, defaulted for other options, imported the selected literature data, and got Keyword co-emerging map (Fig.6). As shown in Fig. 6, the co-occurrence graph of key words in carbon emission research of the steel industry has a total of 451 nodes, 918 connections, and a network density of 0.009. Among them, the size of the keyword node corresponds to its frequency.
In addition, the mediating centrality of each keyword can be obtained from the keyword co-occurrence graph. The node with high centrality is the bridge connecting each keyword, and the higher the value of the keyword is, the more critical the keyword is in its research hotspots. The top ten keywords with the highest frequency and the highest intermediary centrality were sorted out through the keyword co-occurrence map of carbon emissions research in the steel industry, as shown in Table 4. Summing up the two overlapping keywords, divided into three categories: carbon emissions, efficiency and China, they can be regarded as the most important connecting hub of hot keywords in the research field of carbon emissions in the steel industry.
Table4Frequency and centrality of top ten keywords in Carbon Emission Research of iron and steel industry
Ranking
|
High frequency keywords
|
Frequency
|
First year
|
Key words of heart type in Senior High School
|
Intermediary centrality
|
First year
|
1
|
Co2 emission
|
110
|
1997
|
Carbon dioxide emission
|
0.35
|
1992
|
2
|
Steel industry
|
73
|
2007
|
Co2 emission
|
0.17
|
1997
|
3
|
Iron
|
67
|
1992
|
China
|
0.15
|
2002
|
4
|
Carbon dioxide emission
|
51
|
1992
|
Intensity
|
0.14
|
2002
|
5
|
China
|
44
|
2002
|
Iron and steel industry
|
0.13
|
2000
|
6
|
Consumption
|
43
|
2006
|
Model
|
0.12
|
2000
|
7
|
Industry
|
43
|
1997
|
Bioma
|
0.11
|
2009
|
8
|
Efficiency
|
42
|
2007
|
Blast furnace
|
0.10
|
2006
|
9
|
Reduction
|
42
|
2014
|
Carbon dioxide
|
0.10
|
1994
|
10
|
Energy
|
41
|
2002
|
Efficiency
|
0.08
|
2007
|
Analysis of Hot Research Topics
Keywords clustering can deepen the co-occurrence relationship of keywords and calculate a group of keywords with a closer relationship, so as to form a topic clustering containing multiple groups of words.In order to further investigate the knowledge structure of carbon emissions in the steel industry and explore the research hotspots, this paper conducted cluster analysis on the key words. Run the software to obtain the correlation clustering map (Fig. 7).From the clustering map, we can see that the Modularity module value (Q value) is 0.8166, greater than 0.3, indicating that the clustering results are significant. And Mean Silhouette: the Mean contour value (S value) of the clustering is 0.9306, greater than 0.7, indicating that the clustering is highly credible. Scholars closely focused on carbon dioxide emissions and steel industry research, formed a total of 10 keywords cluster research hotspots. In the following, the clustering shown is sorted out and analyzed, and three hot research topics are formed.
Topic 1: Climate change-oriented carbon emissions from the steel industry. Topics in this category include Cluster #3 Climate Change Policy and Cluster #6 climate change. The key words include climate change policy, carbon emission, dynamic modeling, integrated steel mill, multi-sector, attribute analysis, co-integration method, etc. at the present stage, Climate degradation is now one of the most serious threats to human habitat, and changing it will require fundamental changes in our daily social and economic lives. Steel production is a special case of economic activity, which is not only related to combustion, but also closely related to greenhouse gas emissions (Mayer et al. 2019). In many developed countries, global climate change has been widely concerned. In order to protect the environment, they have taken more and more measures to deal with greenhouse gases in heavy industries such as steel industry and manufacturing industry (Mert et al. 2018). Among developing countries, China is the country that pays the highest attention to climate change, and the steel industry plays an important role in mitigating global climate deterioration (Li et al. 2019; An et al. 2018). As the world's largest steel producer and consumer, China bears the primary responsibility for energy conservation and emission reduction in the steel industry, and is a key force in reversing the current climate deterioration. China should actively participate in global climate regulation actions. In terms of steel production and supply, low-carbon technology should be promoted in time and clean energy should be used.In terms of steel consumption demand, alternative environmental protection materials can be selected to increase investment in scientific research and reduce the necessary amount of steel, so as to reduce emissions of CO2 and other air pollutants.
Topic 2: Production technology-oriented carbon emissions from the steel industry. Topics in this category include Clusters #0 Iron and Steel Industry, Clusters #1 Steel Scrap, Clusters #2 Coal and Clusters #5 Manufacturing Industry, etc. Keywords include Empirical Analysis, Steel Sector, Industry Processes, Sustainable Iron, Critical Factor, etc. In order to mitigate global warming and climate deterioration, major industrial sectors, such as the steel industry, as one of the most important contributors to man-made CO2 emissions, should not only find more efficient environmental cleaning solutions to reduce CO2 emissions, but also ensure the efficient operation of the solutions and low treatment costs (Chisalita et al. 2019).In the past 10 to 15 years, some large steel manufacturing countries and the research plan of EU is ongoing or already completed, including oxygen blast furnace, utmost ground biomass replace coke, instead of carbon hydrogen, carbon dioxide capture and storage (CCS) and other new technologies, these technologies through production facilities and a total modernization of energy system, and adopt new pioneering method, can make "world steel" in use to achieve a reduction of 0.4-0.5 tons of carbon dioxide per ton of steel level (Holappa 2020). Increasing efforts to reduce carbon emissions from the source of the production line and improving the level of production technology are all important links to effectively control carbon emissions in the steel industry.
Topic 3: Carbon emission study of steel industry based on future scenario analysis. This kind of hot topic includes cluster #4 Scenario Analysis, and the main keywords include atmospheric modeling, chemical evolution, revisiting China's CO emission, etc. The climate targets agreed in Paris in 2015 make deep decarburization of energy and emissions intensive industries essential. Through the scenario study on the zero emission path of the European steel industry, it is found that its carbon emission reduction effect is mainly dependent on technological choice, major macro-economic state and regional characteristics, but the potential socio-economic development and climate policy trajectory have a poor reflection on carbon emission reduction (Sahoo et al. 2019).China, as the largest CO2 emitter in the world, has been actively promoting the development path of carbon emission reduction, and has made a commitment to reach the carbon peak in 2030 in combination with the Paris Agreement (Li and Li 2020). Wei P.B. et al. even established the LEAP policy model, and found that under the policy context of capacity upgrading and energy saving technology research and development, carbon emission reduction in the steel industry has a great prospect and advantage (Bachner et al. 2020; Lu et al. 2020). In the future, with the rapid development of the global economy, the demand for steel will greatly increase, and the research and development of new technologies and the adjustment of energy structure to cope with the future climate change situation are urgent. Carbon emission reduction in the steel industry needs long-term regulation and control. It is an important strategic measure to forecast the future scenario and make corresponding adjustments in time, and it is also a hot topic of research at the present stage.
Frontier Analysis
In order to further explore the future research frontier hot spots in the field of carbon emissions in the steel industry, it is necessary to analyze the evolution trend of the research hot spots. In this paper, CiteSpace software was used to generate the Timezone map (Fig.8). Combined with the current development status of carbon emission research in the steel industry, the evolution process of the hot research topics was analyzed and summarized to predict the future research trends. Among them, the Timezone map focuses on the evolution of research hotspots over time, which can more clearly explain the update status of each research hot spot and its correlation with each other (Wei et al. 2017).
According to Figure 8, the research history of carbon emissions in the steel industry from 1991 to 2020 is divided into three periods: ① From 1991 to 2000, this period was the initial stage of research, dominated by CO2 emission and iron and steel industry, and there were few active research hot topics.Main reason for the related research in this field is headed by the developed countries such as Canada and Mexico were the first to put forward, these countries are in a stage of rapid promotion of industrialization, the demand for energy is also a large increase. And the steel industry, a big user of coal and other forms of energy, is a key target for reducing carbon dioxide emissions (Chen et al. 2015).Under such a background, it is urgent to carry out research on carbon emission of steel industry.Although there are few kinds of research topics in this stage, the research hot spot lasts the longest and is still a hot topic in academic circles. ② From 2001 to 2013, the research hotspots of carbon emissions in the steel industry exploded, including energy efficiency, consumption, air pollution source, hydrocarbon, technology, climate change policy and China, etc. At this time, the research in this field was in the rapid development stage.With the gradual acceleration of global economic growth and increasingly close economic links between countries, the corresponding demand for steel industry is also increasing, the carbon emissions generated are also rising at a very fast rate, and the problem of air pollution is increasingly aggravated (Walsh 1992; Sheinbaum and Rodriguez 1997).In order to prevent further deterioration of this phenomenon in a timely manner, reducing carbon dioxide emissions produced in the industrial process, improving the energy efficiency of the steel industry, improving energy conservation technology, wasting heat utilization technology and using of hydrogen energy for energy substitution had been put on the agenda (Arens et al. 2017; Liang et al. 2009; Moynahan and Allwood 2012). ③ From 2014 to now, this period has been in a stable development stage, and the hot research keywords in this stage include quantitative assessment, techno economic analysis, scenario analysis and environmental benefit, etc.The possibility of achieving zero-emission steelmaking can be investigated by using the techno-economic analysis method. It is found that the combination of CCS (carbon capture and storage) and biomass substitution in blast furnace can effectively reduce CO(2) emissions (Le et al. 2011);And through scenario analysis, it is found that compared with traditional energy, the renewable energy and the innovation of ironmaking technology also shows a strong competitive advantage in terms of greenhouse gas emission reduction and economic cost. In the future, feasible low-carbon path and alternative strategy of renewable energy should be sought based on this (Fujji et al. 2012; Sun et al. 2012).In addition, methods such as Life-cycle assessment(LCA) and Long-term short-term memory (LSTM) also provide theoretical support for carbon emission reduction research in the steel industry (Toktarova et al. 2020; Yang et al. 2021; Shatokha et al.2020).It is obvious that the research in this stage mostly adopts quantitative economic analysis. Compared with the previous stage, the research method is more scientific and the research content is more in-depth. It is no longer limited to the surface of things, but focuses on in-depth analysis of the essential causes of carbon emissions in the steel industry and looking for new development paths.
Through a review of the carbon emission research and development history of the entire steel industry, From the initial proposal of the research topic to the increase of research attention in this field due to global climate change, and then to the application of quantitative economic analysis in this research at the present stage, the research level has been deepened and the research hotspots have gradually increased. And the carbon peak and carbon neutral proposed has triggered the world's scholars to the steel industry carbon emission research field deep thinking. Therefore, under such an environment, in the coming decades, carbon emission research of steel industry will form a breakout point in the academic circle, and the comprehensive application of various econometric analysis, technical and economic analysis and environmental climatology in this field will be the frontier hotspot of future research.