CFD simulation and optimization of turning different waste gases into energy in an industrial steam methane reformer

Abstract

BackgroundOne of the most important processes of industrial hydrogen production is steam methane reforming (SMR). However, the biggest drawback of steam reformer processes is high energy consumption. In methanol production units, 40% of the energy consumed in the steam reformer is provided by methane burning. The best solution to reduce the consumption of methane gas is to use the waste gases of the units. InnovationTo boost the thermal performance of the furnace, as well as the reduction in natural gas utilization, the effects of the kinds of fuel in an industrial unit are investigated. Furthermore, the waste gas is studied to whether it can be used as fuel in an SMR or not. SignificanceCFD is one of the most powerful tools for simulation of the industrial by which a new unit can be set up or the performance of the old units can be developed. Additionally, the effect of diverse parameters on industrial processes can be examined, and the optimal operating conditions of the industrial unit can be found. MethodsIn this study for five different cases of fuel, the furnace of an industrial SMR unit, at the operating conditions, was simulated using Computational Fluid Dynamics, (CFD) and the results were validated by the industrial data. Moreover, regarding the higher thermal efficiency of the furnace and the lower consumption of natural gas, two cases called design, and the suggested modes, were investigated and suggested mode was proposed as the most suitable fuel. FindingBased on the results, removing purge gas and adding waste gases with lower hydrogen content are recommended. Compared with the operational fuel, the suggested mode decreases the flue gas temperature by 11.78 K and increases the temperature of the first row of the reformer tubes by about 4.17 K, while declining the natural gas molar flow rate by 32%. A 64% reduction in hydrogen content of the suggested mode leads to an increase 10% flame length and 14% enhancement of adsorbed radiative heat flux. Moreover, in the suggested mode it is possible to recycle the purge gas to the methanol synthesis reactor and enhance the methanol production to 1% which is 50 ton/day.