Heat Integration in a Cement Production

The cement industry sector is an energy-intensive industrial sector; cement is the most widely used material for construction and modern infrastructure needs. The cement industry is one of the largest consumers of carbon-containing primary energy sources and one of the primary polluters of the environment. Energy consumption represents the largest part of the production cost for cement factories and has a significant influence on product prices. The potential of waste heat utilization of cement production was determined and a recovery potential accounting site wide in demand is defined by the process integration technique. The author has analyzed the energy consumption of a cement factory to obtain minimum energy needs of production and proposed the options to improve energy efficiency by the process integration approach. The authors conclude that the energy consumption of the cement factory can be reduced by 30%. The results help to the cement plant’s profitability and reduce environmental impact of the cement industry as well as sustainability. Given that it is realized in modern society that infrastructural projects lead to a higher level of economy and sustainability for countries, reducing the production cost in the cement industry is a very important problem

Capital Cost Targeting of Total Site Heat Recovery

Exploiting heat recovery on Total Site level offers additional potential for energy saving through the central utility system. In the original Total Site Methodology (Klemeš et al., 1997) a single uniform ΔTmin specification was used. It is unrealistic to expect uniform ΔTmin for heat exchange for all site processes and also between processes and the utility system. The current work deals with the evaluation of the capital cost for the generation and use of site utilities (e.g. steam, hot water, cooling water), which enables the evaluation of the trade-off between heat recovery and capital cost targets for Total Sites, thus allowing to set optimal ΔTmin values for the various processes. The procedure involves the construction of Total Site Profiles and Site Utility Composite Curves and the further identification of the various utility generation and use regions at the profile-utility interfaces. This is followed by the identification of the relevant Enthalpy Intervals in the Balanced Composite Curves. A preliminary result for evaluation of heat recovery rate and capital cost can be obtained

Thermodynamics-Based Process Sustainability Evaluation

This article considers the problem of the evaluation of the sustainability of heterogeneous process systems, which can have different areas of focus: from single process operations to complete supply chains. The proposed method defines exergy-based concepts to evaluate the assets, liabilities, and the exergy footprint of the analysed process systems, ensuring that they are suitable for Life Cycle Assessment. The proposed concepts, evaluation framework and cumulative Exergy Composite Curves allow the quantitative assessment of process systems, including alternative solutions. The provided case studies clearly illustrate the applicability of the method and the close quantitative relationship between the exergy profit and the potential sustainability contribution of the proposed solutions. The first case study demonstrates how the method is applied to the separation and reuse of an acetic-acid-containing waste stream. It is shown that the current process is not sustainable and needs substantial external exergy input and deeper analysis. The second case study concerns Municipal Solid Waste treatment and shows the potential value and sustainability benefit that can be achieved by the extraction of useful chemicals and waste-to-energy conversion. The proposed exergy footprint accounting framework clearly demonstrates the potential to be applied to sustainability assessment and process improvement while simultaneously tracking di erent kinds of resources and impacts