A radiofrequency heated reactor system for post-combustion carbon capture

Several problems with stabilization of electricity grid system are related to the time lag between the electricity supply and demand of the end users. Many power plants run for a limited period of time to compensate for increased electricity demand during peak hours. The amount of CO2 generated by these power installations can be substantially reduced via the development of new demand side management strategies utilizing CO2 absorption units with a short start-up time. The sorbent can be discharged using radiofrequency (RF) heating to fill the night-time valley in electricity demand helping in the stabilization of electricity grid. Herein a concept of RF heated fixed bed reactor has been demonstrated to remove CO2 from a flue gas using a CaCO3 sorbent. A very stable and reproducible operation has been observed over twenty absorption-desorption cycles. The application of RF heating significantly reduced the transition time required for temperature excursions between the absorption and desorption cycles. The effect of flow reversal during desorption on desorption time has been investigated. The desorption time was reduced by 1.5 times in the revered flow mode and the total duration of a single absorption-desorption cycle was reduced by 20%. A reactor model describing the reduced desorption time has been developed

Integrated catalytic adsorption steam gasification in a bubbling fluidized bed for enhanced H2 production: perspective of design and pilot plant experiences

It is important to build knowledge about the design of an integrated catalytic adsorption (ICA) steam gasification process in a bubbling fluidized bed, which can reduce CO2 content with enhanced hydrogen production. The value of this study is its presentation of detailed design considerations for the performance evaluation of an ICA system using palm oil waste as feedstock. The main advantage of using ICA gasification systems is the CO2 adsorption through a carbonation reaction (using CaO), which helps the water gas shift reaction to move forward. The activity of a catalyst improves steam methane reforming in parallel, which not only produces additional hydrogen but also releases CO to enhance the activity of the water gas shift reaction. The performance of the developed system has shown <1% of temperature variation inside the reactor, which suggested a positive role for exothermic reactions between reactive bed material (CaO) and CO2 in the product gas. The low pressure drop in the gasifier (100–130 mbar) further strengthens the design strategy for the ICA gasification system for hydrogen production. Challenges encountered during the pilot plant operations, and their potential solutions, are discussed to optimize the operation, especially for downstream equipment and auxiliaries

Enhanced hydrogen production from thermochemical processes

To alleviate the pressing problem of greenhouse gas emissions, the development and deployment of sustainable energy technologies is necessary. One potentially viable approach for replacing fossil fuels is the development of a H2 economy. Not only can H2 be used to produce heat and electricity, it is also utilised in ammonia synthesis and hydrocracking. H2 is traditionally generated from thermochemical processes such as steam reforming of hydrocarbons and the water-gas-shift (WGS) reaction. However, these processes suffer from low H2 yields owing to their reversible nature. Removing H2 with membranes and/or extracting CO2 with solid sorbents in situ can overcome these issues by shifting the component equilibrium towards enhanced H2 production via Le Chatelier's principle. This can potentially result in reduced energy consumption, smaller reactor sizes and, therefore, lower capital costs. In light of this, a significant amount of work has been conducted over the past few decades to refine these processes through the development of novel materials and complex models. Here, we critically review the most recent developments in these studies, identify possible research gaps, and offer recommendations for future research