Optimal Tube Bundle Arrangements in Side-Fired Methane Steam Reforming Furnaces

Abstract

Steam methane reforming processes represent the economically most competitive processes for the production of synthesis gas and hydrogen despite their high energy costs. Although there is a strong need for highly resource-efficient production, literature on the optimal design of reformers remains scarce due to the inherently high complexity of these processes. This contribution addresses design aspects of reformers for the case study of a side-fired reformer. Based on a two-dimensional furnace representation heat transfer and the optimal tube bundle arrangement for a fixed furnace chamber are investigated using simulation-based parametric study with both a lean radiation-based model and a computational fluid dynamics model that enables the consideration of fuel efficiency. Radiative heat transfer prevails in the reformer on the furnace side and inter-tube distances of at least three diameters are optimal within the investigated design space. The line arrangement of reformer tubes is beneficial in terms of total heat transferred, fuel efficiency as well as the homogeneity of the tube surface temperatures. These findings pave the way for further studies such as three-dimensional design aspects.

Joule-Heated Catalytic Reactors toward Decarbonization and Process Intensification: A Review

“…During energy transfer to the target materials by the induction process, energy losses could occur via various pathways . Even though the energy losses can be minimized by improving the design of the reactor, such as by using high radio frequency and long/narrow coils, to the best of our knowledge the energy efficiency reported so far for induction heating of catalytic processes remains low (below 25%). − ,− Considerations about the possible efficiency improvements when scaling-up are reported in a recent work by Almind and co-workers: an energy efficiency up to 80% could be expected upon upscaling, according to their theoretical estimation.…”

“…The flue gases at the outlet of the reactor are then used to produce the steam required for the reaction and extra-steam for export in order to maximize heat recovery from flue gases. On one hand, the heat transfer limitations of the methane steam reforming process has been a subject of research for decades, especially when trying to operate the system at the small scale. ,,− On the other hand, the fuel combustion is responsible for roughly half of the CO 2 emission of this process. − It is estimated that the industrial MSR process accounts for approximately 0.5% of global CO 2 emission . Another relevant aspect is that a relatively high dilution makes the recovery of CO 2 from the flue gas (8–10% CO 2 ) more difficult and expensive than from the main process stream (approximately 45% CO 2, considering PSA off-gases), thus negatively affecting the economics of “blue hydrogen” production.…”

“…Electricity can be converted into heat and transferred to thermally driven chemical reactors in several ways, such as microwave heating, − induction heating, as well as Joule heating ,− (also known as ohmic heating or resistance heating). As shown in Figure , those methods are promising to replace fossil fuel combustion heating and have been explored recently in several industrial processes for chemical syntheses. ,− In addition to the reduction of CO 2 emissions by replacing fuel combustion, electricity-to-heat driven catalytic processes may enable significantly enhanced heat transfer as the catalysts could be located in intimate contact with the heating elements. This may enable process intensification with the design of compact reactors and reduce the intrinsic heat transfer limitations that affect some of the most widespread chemical processes.…”

Numerical Evaluation of Heat Transfer and Conversion Efficiency by Tube Design and Flow Configuration for a Compact Steam-Methane Reformer

“…Alternatively, solar heat energy can also be employed as a heat source [16,17]. To enhance heat transfer, the arrangement of the catalyst tubes is a critical design parameter [18]. In particular, the counter-flow arrangement of the catalyst layer relative to the hot gas (heat source) and the uniform flow of the hot gas can increase heat transfer, resulting in higher methane conversion [19].…”