Electroreduction of CO2/CO to C2 products: process modeling, downstream separation, system integration, and economic analysis.

Direct electrochemical reduction of CO2 to C2 products such as ethylene is more efficient in alkaline media, but it suffers from parasitic loss of reactants due to (bi)carbonate formation. A two-step process where the CO2 is first electrochemically reduced to CO and subsequently converted to desired C2 products has the potential to overcome the limitations posed by direct CO2 electroreduction. In this study, we investigated the technical and economic feasibility of the direct and indirect CO2 conversion routes to C2 products. For the indirect route, CO2 to CO conversion in a high temperature solid oxide electrolysis cell (SOEC) or a low temperature electrolyzer has been considered. The product distribution, conversion, selectivities, current densities, and cell potentials are different for both CO2 conversion routes, which affects the downstream processing and the economics. A detailed process design and techno-economic analysis of both CO2 conversion pathways are presented, which includes CO2 capture, CO2 (and CO) conversion, CO2 (and CO) recycling, and product separation. Our economic analysis shows that both conversion routes are not profitable under the base case scenario, but the economics can be improved significantly by reducing the cell voltage, the capital cost of the electrolyzers, and the electricity price. For both routes, a cell voltage of 2.5 V, a capital cost of $10,000/m2, and an electricity price of <$20/MWh will yield a positive net present value and payback times of less than 15 years. Overall, the high temperature (SOEC-based) two-step conversion process has a greater potential for scale-up than the direct electrochemical conversion route. Strategies for integrating the electrochemical CO2/CO conversion process into the existing gas and oil infrastructure are outlined. Current barriers for industrialization of CO2 electrolyzers and possible solutions are discussed as well

The poetics of justice: aphorism and chorus as modes of anti-racism

This article revisits accounts of the black radical tradition as a critique and alternative to institutionalised modes of knowledge and learning, reprising Harney and Moten’s concept of the undercommons to think about the constraints of the university and the possibility for thinking differently together. The deployment of linguistic and conceptual difficulty as a tactic of political speech is linked to Sutherland’s discussion of Marx’s poetics, leading to the suggestion that the repetitive interspersing of poetic or theoretical fragments in the public speech of social justice actors operates to create a shared rhythm that establishes mutuality. The piece ends with a discussion of the refashioning of Audre Lorde as a voice punctuating the assertion of anti-racist and intersectional consciousness via social media

Racism, anti-racist practice and social work: articulating the teaching and learning experiences of Black social workers

In the mid 1990s a Black practice teacher programme was established in Manchester and Merseyside with the primary aim to increase the number of Black practice teachers in social work organisations, and in turn provide a supportive and encouraging learning environment for Black student social workers whilst on placement. In the north‐west of England research has been undertaken, to establish the quality of the practice teaching and student learning taking place with Black practice teachers and students. This paper is an exploration of the ideas generated within the placement process that particularly focused on the discourse of racism and ant‐racist practice. Black students and practice teachers explain their understanding of racism and anti‐racist practice within social work. From the research, the paper will critique some of the ideas concerning anti‐racism. In particular, it will question whether anti‐racist social work practice needs to be re‐evaluated in the light of a context with new migrants, asylum seekers and refugees. It will concluded, by arguing that whilst the terms anti‐racism, Black and Minority Ethnic have resonance as a form of political strategic essentialism, it is important to develop more positive representations in the future

High pressure electrochemical reduction of CO2 to formic acid/formate: a comparison between bipolar membranes and cation exchange membranes

A high pressure semicontinuous batch electrolyzer is used to convert CO2 to formic acid/formate on a tin-based cathode using bipolar membranes (BPMs) and cation exchange membranes (CEMs). The effects of CO2 pressure up to 50 bar, electrolyte concentration, flow rate, cell potential, and the two types of membranes on the current density (CD) and Faraday efficiency (FE) for formic acid/formate are investigated. Increasing the CO2 pressure yields a high FE up to 90% at a cell potential of 3.5 V and a CD of ∼30 mA/cm2. The FE decreases significantly at higher cell potentials and current densities, and lower pressures. Up to 2 wt % formate was produced at a cell potential of 4 V, a CD of ∼100 mA/cm2, and a FE of 65%. The advantages and disadvantages of using BPMs and CEMs in electrochemical cells for CO2 conversion to formic acid/formate are discussed