CFD modeling of a industrial-scale steam methane reforming furnace

Summary
The increased level of emissions of carbon dioxide into the atmosphere due to burning of fossil fuels represents one of the main barriers toward the reduction of greenhouse gases and the control of global warming. In the last decades, the use of renewable and clean sources of energies such as solar and wind energies has been increased extensively. However, due to the tremendously increasing world energy demand, fossil fuels would continue in use for decades which necessitates the integration of carbon capture technologies (CCTs) in power plants. These technologies include oxycombustion, pre-combustion, and post-combustion carbon capture. Oxycombustion technology is one of the most promising carbon capture technologies as it can be applied with slight modifications to existing power plants or to new power plants. In this technology, fuel is burned using an oxidizer mixture of pure oxygen plus recycled exhaust gases (consists mainly of CO2). The oxycombustion process results in highly CO2-concentrated exhaust gases, which facilitates the capture process of CO2 after H2O condensation. The captured CO2 can be used for industrial applications or can be sequestrated. The current work reviews the current status of oxycombustion technology and its applications in existing conventional combustion systems (including gas turbines and boilers) and novel oxygen transport reactors (OTRs). The review starts with an introduction to the available CCTs with emphasis on their different applications and limitations of use, followed by a review on oxycombustion applications in different combustion systems utilizing gaseous, liquid, and coal fuels. The current status and technology readiness level of oxycombustion technology is discussed. The novel application of oxycombustion technology in OTRs is analyzed in some details. The analyses of OTRs include oxygen permeation technique, fabrication of oxygen transport membranes (OTMs), calculation of oxygen permeation flux, and coupling between oxygen separation and oxycombustion of fuel within the same unit called OTR. The oxycombustion process inside OTR is analyzed considering coal and gaseous fuels. The future trends of oxycombustion technology are itemized and discussed in details in the present study including: (i) ITMs for syngas production; (ii) combustion utilizing liquid fuels in OTRs; (iii) oxy-combustion integrated power plants and (iv) third generation technologies for CO2 capture. Techno-economic analysis of oxycombustion integrated systems is also discussed trying to assess the future prospects of this technology. Copyright © 2017 John Wiley & Sons, Ltd.

Oxy-fuel combustion technology: current status, applications, and trends

Exergoeconomic analysis and optimization of a solar based multigeneration system using multiobjective differential evolution algorithm

CO2 is a major greenhouse gas emitted at the global scale from burning fossil fuels. Converting CO2 to chemicals such as syngas is a promising way to reduce CO2 emissions from stationary sources. In this work, we explore technologies for the thermochemical conversion of CO2 to syngas using both rigorous and reduced order reactor models. Specifically, we study the CO2 utilization potentials of primary reforming such as dry reforming (DR), steam methane reforming (SMR) and partial oxidation (POX), and combined reforming such as combined dry and steam methane reforming (CDSMR), auto-thermal reforming (ATR), combined partial oxidation and dry reforming (PODR) and tri-reforming (TR). Through detailed simulation and analysis, we show the importance of considering rigorous models for accurate prediction. We also develop algebraic surrogate models for reactor outlets as functions of reactor design and operating conditions. The replacement of the high-fidelity models with their simpler algebraic surrogates provides an efficient way for superstructure-based reactor synthesis. Using a mixed-integer nonlinear optimization (MINLP)-based reactor synthesis model, the reactors are further optimized for maximizing CO2 utilization and syngas selectivity. PODR has been found to have the highest potential for converting CO2 for the range of syngas ratios (H2/CO) between 1 and 1.7, achieving almost 100% CO2 conversion with a syngas selectivity ranging 80–93%. We further improve the conversion and syngas selectivity by distributing the feeds to multiple reformers. A combination of DR, CDSMR and TR achieves the best CO2 conversion for syngas ratios up to 2.4. For higher syngas ratios, a combination of SMR, TR and RWGS are found to be optimal. These are non-intuitive results that need further attention.

Simulation and optimization of reforming reactors for carbon dioxide utilization using both rigorous and reduced models

Hydrogen has a potential to be a clean energy carrier that emits only water after combustion and can be produced from diverse feedstocks. Hydrogen has much better combustion characteristics in conv...

Muhammad Ibrar Hussain

Papers

On the Modeling of Steam Methane Reforming

Optimal Design of a Solar Collector for Required Flux Distribution on a Tubular Receiver