(164b) Developing Material and Process Design Solutions for Enhanced Energy Utilization of Industrial Flare Streams

Monzure-Khoda Kazi^a, Fadwa Eljack^a,*, Vasiliki Kazantzi^b

^aQatar University, Department of Chemical Engineering, College of Engineering, Doha P.O. Box-2713, Qatar

^bUniversity of Thessaly, Larissa 41500, Greece

The development of effective solution strategies for enhancing the utilization of waste streams’ energy in industrial processes has become one of the major challenges. The large amounts of waste heat is leading to significant economic losses and adverse environmental consequences (EIA, 2016).

Flare streams that are generated either through routine process operations or abnormal process situations, are considered free energy sources that may be utilized to supplement process energy requirements. However, the composition and energy content of these sources vary significantly, leading to difficulties in evaluating their energy utilization efficiencies and optimal process design, and hence as well as in effectively implementing the flare recovery system’s design (Kazi et al., 2018).

Nevertheless, alternative process design schemes for flare streams’ recovery and utilization have been developed, analyzed and optimized taking into consideration the aforementioned issues with the aim to achieve certain process objectives: namely to minimize total annualized cost while taking into account environmental and technical considerations (Kazi et al., 2018). The previously developed optimization model was formulated based on economic objectives that can next be evaluated and traded-off with respect to other performance criteria, such as environmental targets and operational aspects. Furthermore, this process design approach offered valuable insights in determining optimal flare management strategies compromising conflicting process objectives, as well as in identifying certain flare management bottlenecks, mostly due to constrained design performance and operational limitations, such as limited energy recovery and utilization efficiency, sudden pressure changes during abnormal process operation that may lead to system’s instability, etc. These bottlenecks may, however, be adequately addressed by directly considering the property-related performance targets that are to be achieved thus becoming the design challenges for the proposed research work.

Property-based process integration techniques can be employed to target performance improvements based on potential process and material modifications (Eljack et al., 2008). This work aims at developing a systematic framework for identifying optimal material and process design solutions for overcoming flare management bottlenecks identified in previous work. In particular, a reverse problem formulation is used to tackle the enhanced energy utilization problem. Towards this direction, process performance criteria are first established (e.g. flare amount utilization, design and operational targets that enhance process performance) for which specific material properties (e.g. heat capacity, conductivity, etc) related to this performance are directly identified and analyzed. Next, appropriate property prediction models, that are able to evaluate target properties and properties of mixtures of flare resources, are developed and tested. Furthermore, process (design and operational) constraints are translated into corresponding property-based constraints for the specific problem, while property-based process targets are directly linked to the required (tailor-made) materials and process modifications. The particular objective involves the identification (screening and testing) of appropriate materials that can deliver the required flare recovery tasks and utilize larger volumes of intermediate flare streams. Next, this work will expand to simultaneously consider the design of specific materials and processes that can address the implementation challenges and bottlenecks emerging during abnormal situations.

References

EIA, 2016. Annual energy outlook 2016 with projections to 2040. U.S. Engergy Information Administration.

Eljack, F.T., Solvason, C.C., Chemmangattuvalappil, N., Eden, M.R., 2008. A Property Based Approach for Simultaneous Process and Molecular Design* *Supported by the US NSF CAREER Program (CTS-0546925) and in part through a travel grant (0647113). Chinese Journal of Chemical Engineering 16, 424-434.

Kazi, M.-K., Eljack, F., Amanullah, M., AlNouss, A., Kazantzi, V., 2018. A process design approach to manage the uncertainty of industrial flaring during abnormal operations. Computers & Chemical Engineering 117, 191-208.