Autothermal Reforming of Glycerol with Supercritical Water for Maximum Power through a Turbine Plus a Fuel Cell

Abstract

An autothermal reforming of glycerol process using supercritical water was proposed to produce maximum power by means of a turbine, from the huge pressure energy of product gas just at the outlet of the reformer, and a proton exchange membrane (PEM) fuel cell, which is fed by a hydrogen-rich stream. The reformate gas is upgraded to hydrogen using serially two water−gas shift reactors and a pressure swing adsorption unit. To achieve the energy self-sufficiency condition, all of the pressure swing adsorption (PSA) off-gas, which mainly consists of methane and non-recovered hydrogen, is used as fuel gas to provide a fraction of the thermal energy required by the overall process, and thus, the oxygen needed within the supercritical autothermal reformer is reduced. The system analysis was performed by simulation using AspenPlus, and simulation results are presented. Different reforming and preheating temperatures were taken, and the best values of both water/glycerol and oxygen/glycerol mole ratios to maximize power production were identified. Thus, by reforming and preheating at 800 °C and 240 atm, a specific power of 1.60 kW/kg of glycerol with exergy and energy efficiencies of 33.5 and 36.0%, respectively, was obtained. In addition, a comparison with the use of glycerol as a fuel in a combined Brayton−Rankine cycle showed a lower overall energy efficiency.

Catalytic Reforming of Oxygenates: State of the Art and Future Prospects

“…Autothermal reforming in supercritical water was investigated by introducing oxygen into the reaction system . On the basis of process simulation and calculations using Aspen Plus, they proposed an energy-sufficient autothermal SCWR system for maximum electrical power generation by using a turbine expander and a PEMFC unit. − The power generation mainly comes in two pathways: (i) the expansion of product gas in the turbine at the outlet of the reformer released huge pressure energy; and (ii) purified hydrogen (up to 99.999 mol % H 2 ) was converted into electrical energy in the PEMFC after being upgraded using serially two WGS reactors and a pressure swing adsorption (PSA) unit. In addition, PSA off gas, which mainly consisted of CH 4 and unrecovered H 2 , was fed into a furnace to provide a proportion of thermal energy for the reforming process.…”

Enhanced Biomass-Derived Glycerol Conversion to Syngas in the CO2 Reforming Process: Influence of the Nickel Loading Method on Physicochemical Properties and Catalytic Performance

“…43 First, two aqueous solutions of nickel nitrate (solution a) and EDTA (solution b) were prepared. The preparation of solutions a and b was performed by the addition of the proper amount of EDTA and Ni in distilled water to obtain the aimed nickel loading (5,10,15, and 20 wt %) and also the desired EDTA/Ni weight ratio of 1, 2, and 3. The pH was adjusted at 8 with an HNO 3 solution and then slowly dropped into a solution to prepare the nickel−EDTA complex solution.…”

“…However, glycerol is produced significantly as a side effect in biodiesel manufacturing. − Nowadays, glycerol (C 3 H 5 (OH) 3 ) is an attractive potential substrate to produce many highly valued chemicals. Glycerol can also be applied to renewable syngas and hydrogen production by catalytically reforming techniques − like steam reforming, , dry reforming, − autothermal reforming, aqueous-phase reforming, , chemical looping reforming, , partial oxidation, supercritical water reforming, and sorption enhanced steam reforming . Dry reforming of glycerol (dry-RG) has emerged as a promising and attractive option due to its advantage in terms of converting CO 2 greenhouse gas to syngas and also production synthesis gas with H 2 /CO ratio lower than 2, which can be utilized in the Fischer–Tropsch (F–T) synthesis for producing a wide range of chemicals and liquid fuels .…”