(248h) Toward the Optimization of Carbon and Energy Integration in Industrial Parks

Greenhouse gas (GHG) emission regulations have been increasingly intensified over the past few decades. Many regulations are designed to set specific targets on carbon dioxide, the main constituent of GHG emissions. The industrial sector is constantly identified as a major source for various carbon dioxide emissions, as a result of its heavy reliance on fuel combustion for power generation, and other emission-inducing operations. Many industries are targeting reduced specific energy consumption, by implementing energy efficiency enhancement, fuel switching, and Carbon Capture, Sequestration, and Utilization (CCUS). While the first two emission reduction options minimize the amount of carbon dioxide discharged from a potential source, CCUS reduces carbon dioxide footprint using end-of-pipe treatment options.

Carbon dioxide may be captured from a potential emission source using three different methods: pre-combustion, oxyfuel combustion, and post-combustion. Afterwards, any captured carbon dioxide may be compressed and transported for sequestration or utilization in an appropriate sink. More recently, carbon integration methods that involve the identification of optimum connections between carbon sources and carbon sinks at minimum cost, whilst meeting a specific carbon reduction cut have been introduced

Typically, post-combustion carbon capture is implemented using an absorption unit which mainly separates carbon dioxide from the remaining exhaust gas, before its emission to the atmosphere. However, it should be noted that CCUS is an energy intensive process, and this often results in additional energy demand, as well as and carbon dioxide emissions. In principal, energy integration may allow excess heat from energy-source processes to be utilized in energy-sink processes, which could offset steam generation demand from the utility system and consequently reduces the fossil fuel combustion and carbon dioxide emissions. Any additional low-quality waste heat may then be ejected into cooling utilities. Hence, the additional energy may be used for solvent regeneration within the absorption unit or power generation for CCUS.

Hence, there is exists great opportunities for synergy between energy and carbon integration, by utilizing excess waste heat for carbon integration. While the low-quality energy may be used to supplement the energy demand for CCUS, any additional energy requirements for carbon dioxide compression and transportation must be assessed. Therefore, this work addresses the energy and carbon integration to achieve low cost carbon footprint reductions and enhance the CCUS capture efficency. A mixed-integer non-linear programming (MINLP) model is proposed to explore the synergy between energy and carbon integration, for industrial sites that are served by a centralized utility system. The proposed optimization model is capable of simultaneously solving the energy and the carbon problem, so as to achieve an optimal carbon footprint reduction at minimum cost. A case study was used to demonstrate the potential benefits that can be achieved from this synergy, as well as highlight the significant cost savings and energy reduction footprints that may be attained.