Wenqiang Sun

Change in Carbon Dioxide (CO2) Emissions From Energy Use in China's Iron and Steel Industry

As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide (COz) emissions, the China s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use. The logarithmic mean Divisia index (LMDI) technique is used to decompose total change in CO2 emissions into four factors: emission factor effect, energy structure effect, energy consumption effect, and steel production effect. The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions; whereas the energy consumption effect contributes most to the reduction in CO2 emissions. And the emission factor effect makes a weak negative contribution to the increase of CO2 emissions. To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions, the correlation equations are also proposed.

Decomposition analysis of energy-related carbon dioxide emissions in the iron and steel industry in China

This work aims to identify the main factors influencing the energy-related carbon dioxide (CO2) emissions from the iron and steel industry in China during the period of 1995–2007. The logarithmic mean divisia index (LMDI) technique was applied with period-wise analysis and time-series analysis. Changes in energyrelated CO2 emissions were decomposed into four factors: emission factor effect, energy structure effect, energy consumption effect, and the steel production effect. The results show that steel production is the major factor responsible for the rise in CO2 emissions during the sampling period; on the other hand the energy consumption is the largest contributor to the decrease in CO2 emissions. To a lesser extent, the emission factor and energy structure effects have both negative and positive contributions to CO2 emissions, respectively. Policy implications are provided regarding the reduction of CO2 emissions from the iron and steel industry in China, such as controlling the overgrowth of steel production, improving energy-saving technologies, and introducing low-carbon energy sources into the iron and steel industry.

Specific Energy Consumption Analysis Model and Its Application in Typical Steel Manufacturing Process

Theoretical minimum and actual specific energy consumptions (SEC) of typical manufacturing process (SMP) were studied. Firstly, a process division of a typical SMP in question was conducted with the theory of SEC analysis. Secondly, an exergy analysis model of a subsystem consisting of several parallel processes and a SEC analysis model of SMP were developed. And finally, based on the analysis models, the SEC of SMP was analyzed by means of the statistical significance. The results show that the SEC of typical SMP comprises the theoretical minimum SEC and the additional SEC derived from the irreversibility; and the SMP has a theoretical minimum SEC of 6.74 GJ/t and an additional SEC of 19.32 GJ/t, which account for 25.88% and 74.12% of the actual SEC, respectively.

Plant-Wide Supply-Demand Forecast and Optimization of Byproduct Gas System in Steel Plant

Considerable energy is consumed during steel manufacturing process. Byproduct gas emerges as secondary energy in the process; however, it is also an atmospheric pollution source if it is released into the air. Therefore, the optimal utilization of byproduct gas not only saves energy but also protects environment. To solve this issue, a forecast model of gas supply, gas demand and surplus gas in a steel plant was proposed. With the progress of energy conservation, the amount of surplus gas was very large. In a steel plant, the surplus gas was usually sent to boilers to generate steam. However, each boiler had an individual efficiency. So the optimization of the utilization of surplus gas in boilers was a key topic. A dynamic programming method was used to develop an optimal utilization strategy for surplus gas. Finally, a case study providing a sound confirmation was given.

Optimization and Scheduling of Byproduct Gas System in Steel Plant

A mathematical model was proposed to optimize byproduct gas system and reduce the total cost. The scope and boundaries of the system were also discussed at the same time. Boilers and gasholders were buffer users to solve the fluctuation of byproduct gases. The priority of gasholders should be ranked the last. The allocation of surplus gases among gasholders and boilers was also discussed to make full use of gases and realize zero emission targets. Case study shows that the proposed model made good use of byproduct gases and at least 7.8% operation cost was reduced, compared with real data in iron and steel industry.

Construction of Energy Management and Control Information System in Iron and Steel Enterprise

The contribution of energy management and control information system (EMS) to energy conservation and emission reduction of iron and steel industry was expounded in this paper. According to the different management modes and system coverage of iron and steel enterprises, three basic application categories of EMS were summarized. Then, the application functions and their descriptions were studied in detail, followed by the introduction of the relationship between EMS and other information systems. Finally, the comprehensive evaluation indices and recommended standards of EMS were given. It provides a guideline for iron and steel enterprises to construct EMS, beneficial to the energy conservation and environmental protection.

Material Metabolism and Environmental Emissions of BF-BOF and EAF Steel Production Routes

ABSTRACT As an energy-intensive industry, iron and steel production are suffering from the resource and environmental issues. Blast furnace—basic oxygen furnace (BF-BOF) process and electric arc furnace (EAF) process are the two most common routes of steel production. Therefore, it is very important to quantify the industrial metabolism for the two routes. In this work, material flow analysis is used to comparatively investigate the energy efficiency, material efficiency, and emissions intensity at the enterprise level. The results show that the total energy consumption and material consumption per ton of steel of the BF-BOF route are 2.8 and 11 times larger than those of the EAF route, respectively. In addition, the emission intensities of dust, CO2, SO2, NO2 and CO of the BF-BOF route are 7.7, 2.6, 92.6, 33.5, and 12.0 times greater than those of the EAF route, respectively. To achieve a more sustainable steel industry, some policy recommendations are put forward finally.

Research on Effective Utilization Degree of Energy in Batch-Type Furnace Based on Thermal Value Theory

In the paper, the exact definition of thermal value was proposed and the mathematical model of effective utilization degree of energy in batch-type heating furnace was developed to give the thermal value equations derived from Stalk’s formula. It was achieved that the heat attached on the steel slab injected into the batch-type furnace uniformly would have higher thermal value when the intake time was closer to the end of heating; as for heat attached on furnace gas, the closer to gas supplying, the higher thermal value will be got. And higher thermal value of heat attached on steel slab could be achieved at higher productivity. The factors of steel slab such as overall dimension, physical properties, and heating initial condition and boundary condition, which affected the productivity of furnace, were pointed out to be influencing factors of thermal value.

Emission characterization of particulate matter in the ironmaking process

ABSTRACT The study is to provide a detailed physical and chemical characterization of particles collected in the ironmaking process, including a bunker system, a cast house and a pulverized coal feeding system. Using gravimetric, scanning electron microscope coupled with energy dispersive X-ray spectrometry (SEM-EDS), X-ray fluorescence spectrometry (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES) analyses, the size distribution, morphology, elemental composition and emission factor of particles were investigated. The contribution rates of cast house for emission factors of total suspended particulates (TSP), PM10 and PM2.5 are the largest, 57.0%, 75.5% and 83.3%, respectively. SEM-EDS analysis indicated that cast house particle shapes are mainly formed by polymerization from spherical particles and ultrafine particles, whose main component is Fe. But, the particles of the bunker system or the pulverized coal feeding system are mainly the large ones of irregular block or powder particles and the main component is carbon. The highest content of the element in particles of the bunker system and cast house is Fe, followed by C, Si, Ca and Al. The main elements of particles in the pulverized coal feeding system are C, Si, Al and Ca, and their contents are 63.6%, 7.83%, 3.07% and 1.47%, respectively.

Particulate Matter Emission in Iron and Steelmaking Plants

This chapter describes the emission and control of primary particulate matter (PM) in iron and steelmaking plants. The organized and unorganized emission sources of total suspended particulates (TSP) are presented and their emission amounts are reported. Considering the increasingly strict environmental air quality requirements, the emissions of inhalable particles (PM10) and fine particles (PM2.5) during the iron and steelmaking processes are further discussed. For a sustainable and green iron and steel production, effective dust removal technologies adopted at present and should be developed and promoted in the future are also presented in this chapter.