CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem “CO2 emissions” from todays’ industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO2-based chemistry does...

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

Starting with coal, followed by petroleum oil and natural gas, the utilization of fossil fuels has allowed the fast and unprecedented development of human society. However, the burning of these resources in ever increasing pace is accompanied by large amounts of anthropogenic CO2 emissions, which are outpacing the natural carbon cycle, causing adverse global environmental changes, the full extent of which is still unclear. Even through fossil fuels are still abundant, they are nevertheless limited and will, in time, be depleted. Chemical recycling of CO2 to renewable fuels and materials, primarily methanol, offers a powerful alternative to tackle both issues, that is, global climate change and fossil fuel depletion. The energy needed for the reduction of CO2 can come from any renewable energy source such as solar and wind. Methanol, the simplest C1 liquid product that can be easily obtained from any carbon source, including biomass and CO2, has been proposed as a key component of such an anthropogenic carbon cycle in the framework of a “Methanol Economy”. Methanol itself is an excellent fuel for internal combustion engines, fuel cells, stoves, etc. It's dehydration product, dimethyl ether, is a diesel fuel and liquefied petroleum gas (LPG) substitute. Furthermore, methanol can be transformed to ethylene, propylene and most of the petrochemical products currently obtained from fossil fuels. The conversion of CO2 to methanol is discussed in detail in this review.

Recycling of carbon dioxide to methanol and derived products – closing the loop

Correction for ‘Review of electrical energy storage technologies, materials and systems: challenges and prospects for large-scale grid storage’ by Turgut M. Gur, Energy Environ. Sci., 2018, DOI: 10.1039/c8ee01419a.

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Correction: Review of electrical energy storage technologies, materials and systems: challenges and prospects for large-scale grid storage

High-temperature solid oxide electrolysis cells (SOECs) are advanced electrochemical energy storage and conversion devices with high conversion/energy efficiencies. They offer attractive high-temperature co-electrolysis routes that reduce extra CO2 emissions, enable large-scale energy storage/conversion and facilitate the integration of renewable energies into the electric grid. Exciting new research has focused on CO2 electrochemical activation/conversion through a co-electrolysis process based on the assumption that difficult CO double bonds can be activated effectively through this electrochemical method. Based on existing investigations, this paper puts forth a comprehensive overview of recent and past developments in co-electrolysis with SOECs for CO2 conversion and utilization. Here, we discuss in detail the approaches of CO2 conversion, the developmental history, the basic principles, the economic feasibility of CO2/H2O co-electrolysis, and the diverse range of fuel electrodes as well as oxygen electrode materials. SOEC performance measurements, characterization and simulations are classified and presented in this paper. SOEC cell and stack designs, fabrications and scale-ups are also summarized and described. In particular, insights into CO2 electrochemical conversions, solid oxide cell material behaviors and degradation mechanisms are highlighted to obtain a better understanding of the high temperature electrolysis process in SOECs. Proposed research directions are also outlined to provide guidelines for future research.

A review of high temperature co-electrolysis of H2O and CO2 to produce sustainable fuels using solid oxide electrolysis cells (SOECs): advanced materials and technology

https://pure.tue.nl/ws/files/101607113/1_s2.0_S0360128516300260_main.pdf

Electrocatalysts for the generation of hydrogen, oxygen and synthesis gas

Elementary reaction modeling of reversible CO/CO 2 electrochemical conversion on patterned nickel electrodes

The invention discloses a method for preparing natural gas by using a solid oxide electrolytic tank adopting renewable power, belonging to the technical field of synthesis gas and natural gas preparation. The method comprises the steps: co-electrolyzing CO2/H2O mixed gas at high temperature through an SOEC (Solid Oxide Electrolyzer Cell) by directly utilizing renewable electrical energy on the basis of the traditional method for preparing natural gas from coal at two steps; efficiently converting the collected CO2 into CO/H2/CH4 mixed gas and pure oxygen; returning the obtained products to a natural gas preparation process so as to be methanated and used by a gasification furnace. By using the method, a novel approach for collecting CO2 in the process of preparing the natural gas by using coal is developed, the feasible application field of the SOEC is expanded, a non-grid-connected utilization way is provided for renewable energy power difficult to get on the internet, the circular utilization of the carbon resource is realized, the energy consumption for preparing the natural gas by using coal is reduced, and the problem that the non-grid-connected renewable energy power is difficult to utilize is solved.

Method for preparing natural gas by using solid oxide electrolytic tank adopting renewable power

Online identification of a link function degradation model for solid oxide fuel cells under varying-load operation

High-temperature electrolysis (HTE) systems are expected to operate with renewable sources as energy storage devices due to their high efficiency, reversibility and eco-friendliness. However, the high capital costs of stacks and heat management devices make capacity optimization of HTE systems necessary in the design phase. The current literature formulates the problem merely under constant loading conditions, which ignores the fact that dynamic operation is essential for renewable energy storage. Under this background, we propose a novel model to incorporate the capacity optimization of HTE systems under volatile loading conditions. Specially, this model is formulated in the form of two-stage stochastic programming in which operation optimization is treated as a subproblem of capacity optimization. The advantages include its ability to analyze the influence of different operating strategies on device capacity and its “min–max” transformation, which is convenient to solve by commercial code. In a case study, we discuss the influences of power source volatility and operating strategy on the optimal capacities. Different changing trends of the optimal device capacities with power source volatility are observed around one particular hydrogen price of approximately 4.2 $/kg, above which the capacities increase with power input volatility; at prices below 4.2 $/kg, the opposite effect occurs due to renewable spillage. In addition, considering the operating strategy, we find that an optimal stack inlet temperature of 1200 K obtains economic results comparable to those in a variant temperature operation and provides useful guidance on the controller design. Compared to previous capacity optimization studies under constant operation, this proposed method shows better system economy; e.g., the net revenue increases by approximately 29.54% and 71.52% for the HTE system under hydro and wind power inputs respectively.

Two-stage stochastic programming-based capacity optimization for a high-temperature electrolysis system considering dynamic operation strategies

High temperature electrolysis using solid oxide electrolysis cell (SOEC) is a promising method for converting electrical energy into chemical energy. The high temperature electrolysis is advantageous compared with low temperature electrolysis owing to its high electricity-to-hydrogen efficiency, fast reaction rate, and relatively low cost. The working principles and thermodynamics of SOEC for H2O electrolysis and H2O/CO2 co-electrolysis are described. The typical materials used for SOEC are reviewed and technical challenges for SOEC durability are discussed. To further decrease the electrical energy consumption, fuel-assisted SOEC is proposed and demonstrated to be feasible for syngas production at very low electrical energy consumption or even power generation. The planar cell and tubular cells are identified as promising designs for commercial SOEC applications. As SOEC requires both electrical energy and thermal energy input, the feasibility of integrating SOEC with nuclear power plant or renewable power plant for clean fuel production is discussed. Mathematical models at different levels contribute to understand the complex transport and reaction phenomena in SOECs and help optimize the SOEC systems. In the end, the challenges of SOEC and future developments are discussed. With further technological development, the SOEC could play an important role in future fuel processing, energy storage, and stabilizing the fluctuating renewable energy.


Keywords:

solid oxide electrolysis cell;
fuel-assisted;
materials;
mathematical models;
configuration;
systems

Wenying Li

Papers

Elementary reaction modeling of reversible CO/CO 2 electrochemical conversion on patterned nickel electrodes

Method for preparing natural gas by using solid oxide electrolytic tank adopting renewable power

Online identification of a link function degradation model for solid oxide fuel cells under varying-load operation

Two-stage stochastic programming-based capacity optimization for a high-temperature electrolysis system considering dynamic operation strategies

High Temperature Electrolysis for Hydrogen or Syngas Production from Nuclear or Renewable Energy