# Scenario-Based Techno-Economic Analysis of Steam Methane Reforming Process for Hydrogen Production
## 1 Introduction  
Energy demand has steadily increased with the growing global economy [1]. Currently, energy generation systems rely heavily on fossil fuels, which lead to global warming, mainly due to the accumulation of CO\({}_{2}\) in the atmosphere [2]. Net emissions of CO\({}_{2}\) by human activities must approach zero to stabilize global mean temperature [3]. Carbon capture and utilization (CCU) and carbon capture and fixation (CCF) are promising approaches for reducing emissions of greenhouse gases (GHGs) and depletion of fossil resources, especially in the chemical industry [4]. For a more fundamental approach, however, it is necessary to develop new energy resources as alternatives to conventional fossil fuels and the corresponding energy generation systems [5]. A range of studies have been conducted to address this problem, including production of biofents from fructose [6], production of drop-in fuels from biomass [7], analysis of energy systems utilizing various renewable resources [8], analysis of potential emissions of GHG from proven reserves of fossil fuels [9]. Especially, hydrogen has received substantial attention as a feasible energy carrier to deliver or store a tremendous amount of energy because of its clean properties [10]. In particular, the potential of hydrogen as an energy carrier for hydrogen refueling stations [11] and hydrogen fuel cell vehicles [12] has been reported. Hydrogen can be produced by various methods, such as coal and biomass gasification, water electrolysis, and steam methane reforming (SMR) [13]. Coal and biomass gasification requires high operating temperatures, thereby resulting in high energy demands to produce small amounts of hydrogen [14]. Water electrolysis uses electricity generated from renewable resources such as wind and solar energy to produce hydrogen [15]. This method has environmental advantages, but because of its high capital cost for construction, it leads to high hydrogen production costs and has limited capacity compared to that of industrial hydrogen production [16]. Given the maturity of the technology and the capability of mass production, SMR is seen as a viable option for hydrogen production in the near future. As shown in Figure 1, the SMR process consists of steam reforming, WGS reaction, and hydrogen purification, and is involved in a series of stages comprising natural gas resource use, hydrogen consumption in industry and fuel cells, and CCU. Hydrogen can potentially be used in a wide range of applications--transportation, industrial, residential, and portable, however, only a fuel cell electric vehicle is shown in Figure 1 as an example for simplicity. Many studies have been reported on SMR, but most of these studies have focused on an individual SMR reactor design [17], a specific SMR reaction [18], a specific water-gas shift (WGS) reaction [19], and the development of a new catalyst to improve the reaction yield [20]. However, in addition to the concerns of individual reactors, enhancing the efficiency and economics of the entire SMR system from a process perspective is important for engineering companies to secure competitiveness. In the hydrogen production process, operating conditions including the pressure of the reformer and the temperature of the WGS reactor are adjustable and design conditions including the number of WGS reactors can also be selected to improve process economics. Additionally, SMR is inevitably accompanied by CO\({}_{2}\) emissions, which need to be isolated to satisfy environmental regulations [21], e.g., using a moving bed adsorption process [22]. The integration of carbon capture and SMR generally increases the cost of hydrogen production. Therefore, carbon capture is worth considering in the design of the entire SMR process because it affects the economics of the process [23].