Process and Carbon Footprint Analyses of the Allam Cycle Power Plant Integrated with an Air Separation Unit

Dan Fernandes,Daniel Chen,Qiang Xu,Song Wang,Russel Buss

doi:10.3390/cleantechnol1010022

Abstract

The Allam cycle is the latest advancement in power generation technologies with a high cycle efficiency, zero NOx emission, and carbon dioxide available at pipeline specification for sequestration and utilization. The Allam cycle plant is a semi-closed, direct-fired, oxy-fuel Brayton cycle that uses high pressure supercritical carbon dioxide as a working fluid with sophisticated heat recuperation. This paper conducted process analyses including exergy analysis, sensitivity analysis, air separation unit (ASU) oxygen pump/compressor option analysis, and carbon footprint analysis for the integrated Allam power plant (natural gas)/ASU complex with a high degree of heat and work integration. Earlier works on exergy analysis were done on the Allam cycle and ASU independently. Exergy analysis on the integrated plants helps identify the equipment with the largest loss of thermodynamic efficiency. Sensitivity analysis investigated the effects of important ASU operational parameters along with equipment constraint limits on the downstream Allam cycle. Energy efficiency and carbon footprint are compared among the state-of-the-art fossil-fuel power generation cycles.

Highlights

The recent report “The Fourth National Climate Assessment” by the US Global Change research program expounds that climate change is real and the global temperature will rise in the future, which will have serious health and economic impacts to the US as well as the rest of the world [1]
In the Allam cycle, the highest exergy destruction is seen in the combustor which is at 31.37%, CthleeannTfeochlnloolw. 2e01d9,b1y the recuperator at 28.68%, and the turbine at 23.62%
This paper presents a detailed model of the Allam cycle combined with an air separation unit (ASU) with a high degree of heat and work integration

Summary

Introduction

The recent report “The Fourth National Climate Assessment” by the US Global Change research program expounds that climate change is real and the global temperature will rise in the future, which will have serious health and economic impacts to the US as well as the rest of the world [1]. The rise in the global emissions of carbon dioxide, approximately 2.7 percent in 2018, will bring fossil fuel production and other industrial emissions to a record high of 37.1 billion tons of carbon dioxide per year. The growth of global economy, especially in developing countries like China and India will swell the energy demand, thereby increasing global emissions of carbon dioxide. One of the major drivers of energy demand is electricity generation which for the most part, involves the generation of carbon dioxide and other greenhouse gas emissions. Twenty five percent (25%) of the global CO2 emissions are from fossil fuel powered plants for electricity and heat production, residential/commercial/public services account for 6%, manufacturing industries

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Conclusion