Evaluation of Industrial Urea Energy Consumption (EC) Based on Life Cycle Assessment (LCA)
Open Access
- 7 May 2020
- journal article
- research article
- Published by MDPI AG in Sustainability
- Vol. 12 (9), 3793
- https://doi.org/10.3390/su12093793
Abstract
With the increasingly prominent environmental problems and the decline of fossil fuel reserves, the reduction of energy consumption (EC) has become a common goal in the world. Urea industry is a typical energy-intensive chemical industry. However, studies just focus on the breakthrough of specific production technology or only consider the EC in the production stage. This results in a lack of evaluations of the life cycle of energy consumption (LcEC). In order to provide a systematic, scientific, and practical theoretical basis for the industrial upgrading and the energy transformation, LcEC of urea production and the greenhouse gas (GHG) emissions generated in the process of EC are studied in this paper. The results show that the average LcEC is about 30.1 GJ/t urea. The EC of the materials preparation stage, synthesis stage, and waste-treatment stage (ECRMP, ECPP, ECWD) is about 0.388 GJ/t urea, 24.8 GJ/t urea, and 4.92 GJ/t urea, accounting for 1.3%, 82.4%, and 16.3% of LcEC, respectively. Thus, the synthesis stage is a dominant energy-consumer, in which 15.4 GJ/t urea of energy, accounting for 62.0% of ECpp, supports steam consumption. According to the energy distribution analysis, it can be concluded that coal presents the primary energy in the process of urea production, which supports 94.4% of LcEC. The proportion of coal consumption is significantly higher than that of the average of 59% in China. Besides, the GHG emissions in the synthesis stage are obviously larger than that in the other stage, with an average of 2.18 t eq.CO2/t urea, accounting for 81.3% of the life cycle of GHG (LcGHG) emissions. In detail, CO2 is the dominant factor accounting for 90.0% of LcGHG emissions, followed by CH4, while N2O is negligible. Coal is the primary source of CO2 emissions. The severe high proportion of coal consumption in the life cycle of urea production is responsible for this high CO2 content of GHG emissions. Therefore, for industrial urea upgrading and energy transformation, reducing coal consumption will still be an important task for energy structure transformation. At the same time, the reformation of synthesis technologies, especially for steam energy-consuming technology, will mainly reduce the EC of the urea industry. Furthermore, the application of green energy will be conducive to a win-win situation for both economic and environmental benefits.Funding Information
- National Key Research and Development Program of China (2018YFC0704703)
This publication has 22 references indexed in Scilit:
- Dehumidification performance investigation of run-around membrane energy exchanger systemThermal Science, 2016
- Development of Low-Carbon-Driven Bio-product Technology Using Lignocellulosic Substrates from Agriculture: Challenges and PerspectivesCurrent Sustainable/Renewable Energy Reports, 2015
- Life cycle assessment of energy consumption and GHG emissions of olefins production from alternative resources in ChinaEnergy Conversion and Management, 2015
- Environmental assessment of marine fuels: liquefied natural gas, liquefied biogas, methanol and bio-methanolJournal of Cleaner Production, 2014
- Energy efficiency analysis on Chinese industrial sectors: an improved Super-SBM model with undesirable outputsJournal of Cleaner Production, 2014
- Techno-economic analysis of the coal-to-olefins process in comparison with the oil-to-olefins processApplied Energy, 2014
- Urea as a hydrogen carrier: a perspective on its potential for safe, sustainable and long-term energy supplyEnergy & Environmental Science, 2011
- Life-cycle energy consumption and greenhouse gas emissions for electricity generation and supply in ChinaApplied Energy, 2011
- Retrofit of ammonia plant for improving energy efficiencyEnergy, 2008
- Life cycle assessment as a tool in environmental impact assessmentEnvironmental Impact Assessment Review, 2000