Design and Costing of CO2 capture from the Flue Gas of a Stream Methane Reformer

Cynthia B. Tarun

Thesis (M.S. Chemical Engineering), University of the Philippines Diliman-2004

Abstract

In the 1997 Kyoto Protocol, the global community signed an agreement to protect the environment from the increase in greenhouse gases (GHGs) in the atmosphere. Carbon dioxide gas (CO2) is the GHG emission of major concern, the principal anthropogenic source of which is from the combustion of coal, oil and natural gas. One of the methods to reduce CO2 emissions is to apply CO2 capture technologies in plants releasing CO2. Hydrogen gas (H2) instead of traditional fuels is considered to be better fuel alternative to promote a GHG-free atmosphere. At present, chemical and petroleum industries are increasing their demand for H2. The primary disadvantage of H2 as a fuel and its other applications is that its production contributes to atmospheric CO2 emissions. hence, implementing CO2 capture technology to the production process will diminish the greenhouse effect. In hydrogen-producing plants, CO2 emissions come from two sources. One source is the flue gas vented from the steam reformer and the other source is gases from the process reactions (steam reforming reactions and water-gas reactions) This considers only the CO2 exiting from the flue gas of a steam methane reformer (SMR), which is formed by burning a fuel such as methane with air. A CO2 capture process using monoethanolamine (MEA) as the acid gas absorbent is simulated using Aspen Plus. An Icarus Process Evaluator (IPE) and other sources are used for cost estimation. The objective of this study is to design and estimate the cost of a CO2 capture process exiting from the flue gas of a steam methane reformer of an H2 production plant. The simulation is set to recover 90% of the CO2 in the flue gas with 98% purity. The MEA used contains 30% amine by weight.

The results of the simulation were analyzed in terms of the most practical design and energy requirement for the CO2 capture plant. Lean loading of 0.2 mole CO2/mole of MEA gives the most practical design. The CO2 capture cost for 0.2 loading is S56/ton of CO2 captured.


Subject Index : Greenhouse gas mitigation