Technical innovations for upscaling and commercialization of the Sorption-Enhanced Reforming technology

Hydrogen - the energy carrier for the future Today, hydrogen is mainly produced at large scale by Steam Methane Reforming (SMR) of natural gas and the integration of CO2 capture is necessary if emissions are to be avoided. The development of technologies with the potential to significantly reduce the CO2 capture cost is therefore required to produce CO2-free hydrogen at a competitive cost. In the TechnoSER project, hydrogen is produced in an innovative, cost-effective reforming process called Sorption Enhanced Reforming (SER). A solid CaO-based CO2-sorbent is added in the reformer reactor, mixed with a reforming catalyst, allowing to capture the CO2 and to enhance the reforming reaction. Due to this modification, the process is intensified, and higher hydrogen concentrations (95-99 mol%, dry basis) are obtained in one single step. Moreover, no shift catalysts are required. A second reactor is needed to regenerate the sorbent and produce nearly pure CO2, where heat has to be provided at high temperatures (800-900°C). SER has been developed by the Institute for Energy Technology (IFE) and ZEG Power over the last decade. The technology has been tested at laboratory scale and verified in a reactor prototype producing about 1 kg H2/hour. The work in TechnoSER is based on this technology development, and the objective is to optimize the process towards upscaling. The following activities have been carried out with objectives to reduce investment and operation costs: A) Modelling of the SER reformer in turbulent mode B) Optimization of the regeneration step through the integration of a pulsed combustion heater C) Optimization of the sorbent material to increase the capture capacity and the mechanical properties D) Performance and cost comparison for upscaling The work performed and the obtained results are briefly described below: A) IFE has developed a model to simulate the fluidized bed reformer in a turbulent flow regime. The approach is based on probabilistic evaluations and has the beneficial feature of providing a reactor model for all possible flow regimes. The model computes the concentration profiles along the axial length of the reactor. The simulations carried out indicate that a doubling of the superficial velocity, from a vigorous bubbling regime to slightly turbulent, results in a reduction of the hydrogen concentration by approximately 5% only. Increasing the gas velocity further still allows high hydrogen concentrations, but the solids inventory increases. B) Based on the heat requirements specified by ZEG and IFE, TRI has delivered the design of a 2nd generation pulsed combustion heater. The results show that even though the combustion heater could bring to several advantages compared to a traditional burner coupled with a u-tube heat exchanger (previous configuration), especially concerning size and heat exchange area, in the application considered this heater wouldn?t bring to lower OPEX as initially hoped. This result is mainly due to the fact that the pulsed combustion heater needs a cooling water circuit to keep the temperature within design limits. This result suggests that this heater might be a good option if export of steam is needed and might be considered for future applications. C) The work on sorbent development has focused on the optimization of the sorbent micro-powder synthesis, with emphasis on the study of the influence of temperature, liquid to solid ratio, reaction time and CaO content on the material performance. Small-scale granulation of the sorbent powder has also been developed and adjusted for an optimized CaO content to ensure satisfactory chemical stability and mechanical strength. The granulated sorbent material produced with the optimized production method shows a stable long-term sorption capacity of about 0.2 g-CO2/g-sorbent after 1000 cycles, and fast reaction kinetics. A hydrogen concentration of 98.7 vol% has been obtained in the SER reaction in bubbling regime using the optimized sorbent mixed with a commercial catalyst. An industrial manufacturing scheme has been developed for the sorbent and the investment cost required for a plant producing 10 tons/day have been evaluated. D) ZEG Power has worked on the optimization of a previously developed process model on the SER base configuration. The model obtained has shown good accordance with previously calculated data from the SER reactor model. The model has been used for comparison of the SER technology with conventional technology. Cost calculation for a 1 MW (30 kg H2/h) and 20 MW (600 kg H2/h) are performed and used for cost comparison with conventional technology (SMR, ATR, and Electrolysis) showing again the competitive position of SER. Additionally, a new design of the high temperature heat exchanger in the regenerator enabling improved scalability.

The ZEG Power business idea is to industrialise the ZEG-technology, and to take it to the market together with key industrial and commercial partners by offering ZEG Power plants of increasing size and complexity, based on the SER technology. The TechnoSER project has allowed to increase knowledge and competence on fluidised bed reactor modelling, alternative heat transfer technologies and industrial ceramic powder processing. This competence is valuable for the further development of the SER process but also for other industrial processes where process intensification can be applied. The work has confirmed the potential to increase the performance and reduce the cost of the SER process. The work will now be used for the construction - in the next 2 years - of a first upscaled 1 MW, which will be followed by several other 1 MW and 20 MW units. The TechnoSER results can increase competitiveness of the SER process, opening several growing hydrogen markets.

Sorption-Enhanced Reforming (SER) is an innovative reforming technology that allows pre-combustion CO2 capture at high temperature. It combines reforming, water gas shift and CO2-capture in the same reactor (reformer) providing a process intensification with hydrogen production in one single step. A high temperature solid CO2 sorbent (usually CaO-based), is introduced and mixed together with the reforming catalyst, in the reaction. The simultaneous removal of CO2 moves the thermodynamic equilibrium towards higher hydrogen production at lower temperatures, and hydrogen concentrations up to 98 vol% (dry basis) can be obtained in the temperature range of 550 ? 650ºC. The CO2 captured as a solid carbonate is released by increasing the temperature in a second reactor, the regenerator. In this step, heat has to be provided via a high temperature heat exchanger or via oxy-combustion. The main goal of TechnoSER is to develop an improved and optimized SER- process for cost-efficient hydrogen production with integrated CO2 capture focused on the main challenges for taking the technology to commercial use: - Efficient heat transfer for regeneration of the CO2-sorbent - Compact design of the reformer - Optimized sorbent materials The expected results are lower energy intensity in the process, as well as lower capital and production costs for hydrogen and for CO2 capture compared to state-of-the-art technologies.