CO2 capture from natural gas combined cycles by CO2 selective membranes

This paper performs a techno-economic analysis of natural gas-fired combined cycle (NGCC) power plants integrated with CO2 selective membranes for post-combustion CO2 capture. The configuration assessed is based on a two-membrane system: a CO2 capture membrane that separates the CO2 for final sequestration and a CO2 recycle membrane that selectively recycles CO2 to the gas turbine compressor inlet in order to increase the CO2 concentration in the gas turbine flue gas. Three different membrane technologies with different permeability and selectivity have been investigated. The mass and energy balances are calculated by integrating a power plant model, a membrane model and a CO2 purification unit model. An economic model is then used to estimate the cost of electricity and of CO2 avoided. A sensitivity analysis on the main process parameters and economic assumptions is also performed. It was found that a combination of a high permeability membrane with moderate selectivity as a recycle membrane and a very high selectivity membrane with high permeability used for the capture membrane resulted in the lowest CO2 avoided cost of 75 US$/tCO2. This plant features a feed pressure of 1.5 bar and a permeate pressure of 0.2 bar for the capture membrane. This result suggests that membrane systems can be competitive for CO2 capture from NGCC power plants when compared with MEA absorption. However, to achieve significant advantages with respect to benchmark MEA capture, better membrane permeability and lower costs are needed with respect to the state of the art technology. In addition, due to the selective recycle, the gas turbine operates with a working fluid highly enriched with CO2. This requires redesigning gas turbine components, which may represent a major challenge for commercial deployment

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

High fidelity model of the oxygen flux across ion transport membrane reactor: Mechanism characterization using experimental data

As a consequence of growing energy demand and expanded use of fossil fuels, CO2 level in the atmosphere has risen in the last couple of centuries. The principal effect of these anthropologic emissions of greenhouse gases is global warming. In the last years, there has been much effort on finding a long term solution to this problem, mostly based on clean power technologies. In order to reduce green-house gas emissions different technologies to capture CO2 are under investigation. One of the most promising technologies is oxy-combustion using ITM (ion transport membranes) used in air separation units or integrated directly in reactors. This work presents a model for the integration of dense oxygen membrane modules in air separation units. An axially resolved model for the distribution of oxygen concentration is developed, incorporating a model of the oxygen flux across membrane surface and its dependency on the local conditions, which satisfies the conservation equations of mass and energy. The oxygen flux model is based on accurate experimental measurements and incorporates the effects of chemistry at the surface and diffusion in the bulk material, as well as heat and mass transport on the feed and sweep side

High efficiency orc for high temperature molten salt boiler for biomass applications

INTRODUCTION Efficient and sustainable production of energy from biomass is one of the key factors in achieving the objectives set out in the Climate and Energy package of the European Commission. In the last decade, European and national research programs have focused both on local planning of biomass-to-energy pathways and on the improvement of the overall efficiency of energy conversion. Biomass-fired small-scale CHP systems can play an important role for the distributed cogeneration and the sustainable usage of local resources, but research is still required to improve the overall efficiency and reduce emissions. The state of the art for wood-fired CHP plants up to 3 MWe is represented by Organic Rankine Cycle (ORC) (Turboden, 2013; Obenberger and Thek, 2008, Dong et al., 2009). It is a consolidated and reliable technology that offers many advantages: relatively high efficiency, simple start up procedures, simple O&M and proven long life (greater than 20 years) (Quoilin and Lemort, 2009; Tchance et al., 2011). This work aims to present an innovative cogenerative Organic Rankine Cycle operating with fluids at high temperature (up to 400°C), coupled with a biomass-fired molten salts boiler, that allow to obtain an electrical efficiency over the threshold of 20%

High dose esomeprazole as an anti-inflammatory agent in sepsis: Protocol for a randomized controlled trial

Background: Sepsis is caused by dysregulated immune responses due to infection and still presents high mortality rate and limited efficacious therapies, apart from antibiotics. Recent evidence suggests that very high dose proton pump inhibitors might regulate major sepsis mediators' secretion by monocytes, which might attenuate excessive host reactions and improve clinical outcomes. This effect is obtained with doses which are approximately 50 times higher than prophylactic esomeprazole single daily administration and 17 times higher than the cumulative dose of a three day prophylaxis. We aim to perform a randomized trial to investigate if high dose esomeprazole reduces organ dysfunction in patients with sepsis or septic shock. Methods: This study, called PPI-SEPSIS, is a multicenter, randomized, double blind, placebo-controlled clinical trial on critically ill septic patients admitted to the emergency department or intensive care unit. A total of 300 patients will be randomized to receive high dose esomeprazole (80 mg bolus followed by 12 mg/h for 72 h and a second 80 mg bolus 12 h after the first one) or equivolume placebo (sodium chloride 0.9%), with 1:1 allocation. The primary endpoint of the study will be mean daily Sequential Organ Failure Assessment (SOFA) score over 10 days. Secondary outcomes will include antibiotic-free days, single organ failure severity, intensive care unit-free days at day 28, and mortality. Discussion: This trial aims to test the efficacy of high dose esomeprazole to reduce acute organ dysfunction in patients with septic shock. Trial registration: This trial was registered on ClinicalTrials.gov with the trial identification NCT03452865 in March 2018

Notulae to the Italian alien vascular flora: 9

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Furthermore, three new combinations are proposed

Effects of pre‐operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05-1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4-7 days or >= 8 days of 1.25 (1.04-1.48), p = 0.015 and 1.31 (1.11-1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care