Newcastle University ePrints -eprint.ncl.ac.uk Adamson R, Hobbs M, Silcock A, Willis MJ. Steady-state optimisation of a multiple cryogenic air separation unit and compressor plant. Applied Energy 2017, 189, 221-232. AbstractThe development and on-line application of a steady-state optimisation strategy for a multiple cryogenic air separation unit and compressor plant is discussed. Implemented using mixed integer linear programming (MILP), it is demonstrated that the optimiser improves site efficiency at steady state by reduction of power consumption by up to 5% (a significant saving for such an energy intensive process) while meeting customer demand specifications. This is achieved through determination of the production distribution of the air separation units and optimal load distribution of the compression network, while simultaneously ensuring network material balance and network component operating constraints are met. In addition, the work demonstrates achievable benefits of demand side load management during peak power pricing periods, using liquid oxygen as an effective energy storage device. A key constituent of the optimisation strategy is linear modelling to predict individual unit power consumption. Piece-wise linear data-based models of compressor and air separation unit power are shown to provide accurate models which improve existing on-site power prediction by up to 80% for compressors and 60% for the air separation units.

This study evaluated for the first time the performance of CSP in a cocurrent downflow packed column operating at a pulsing flow regime. Packing performance was evaluated on a bench-scale absorber equipped with high-speed imaging and pressure gauges. Absorption experiments were conducted at 101.3 kPa using an 8 vol % CO2/air mixture and a 22 mol % MEA solution to determine the overall mass transfer coefficient, K OGa, and absorber height requirements. CSP was shown to be effective in facilitating pulsing at a lower pressure drop by enhancing liquid retention. Periodic pulses generated bubbles of 3–14 mm in diameter, interfacial areas of 200–1600 m2/m3, and K OGa 2–10 times larger than those reported for packed columns under trickle flow regime. CSP showed 2–4 times higher K OGa per unit of pressure drop compared to random packing. CSP performance represents an attractive opportunity to reduce capital (column size reduction and associated installation costs) and operating costs (lower pressure drop and pump energy) for carbon capture and chemical industry essential for the transition toward a low-carbon economy.

No abstract

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence Newcastle University ePrints -eprint.ncl.ac.uk Adamson R, Hobbs M, Silcock A, Willis MJ. Integrated real-time production scheduling of a multiple cryogenic air separation unit and compressor plant.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence Newcastle University ePrints -eprint.ncl.ac.uk Cummings T, Adamson R, Sugden A, Willis MJ. Retrospective and predictive optimal scheduling of nitrogen liquefier units and the effect of renewable generation.