Evaluation of Emissions of 2-Amino-2-Methyl-1-Propanol Degradation Products by adding Degradation Reactions to the Carbon Dioxide Capture Unit

Degradation is a major problem which poses lots of emission risk during chemical absorption process with amine solvents. Degradation occurs through irreversible side reactions with CO2 and other flue gas components, forming into products that cannot easily regenerate. The degradation products then react with amines to form thermally stable salts, which accumulate in the system over time. The problems associated with degradation include decreased plant equipment life, foaming, corrosion, high solution viscosity, and increased operating cost. Amines capture about 70 90% CO2 from commercial power stations. These high removal rates have many environmental impacts due to their degradation products. Researchers have therefore shown interest in characterising and quantifying atmospheric emissions of amines and their degradation products. In this study, 2-Amino-2-Methyl-1-Propanol (AMP) degradation reactions were included into a largescale capture plant model to evaluate the influence of process variables, the emissions of AMP and its degradation products. Steadystate simulations were performed using Aspen Plus® V8.4 software to provide a full assessment of the degradation products and their impact on the capture process. This assessment is important because it identifies and quantifies all pollutants emitted from the process plant. The results of the simulation indicate that AMP emissions are 3.04E+03mg/Nm3 of CO2 lean flue gas, while the quantity of AMP lost due to degradation was 37.88kg/s for the largescale capture plant. The results further showed that among the gases emitted, ammonia was highest, while acetone was the highest gas formed. In this study, 2-amino-2-methyl-1-propanol (AMP) degradation reactions were included into a largescale carbon dioxide (CO2) capture plant model to evaluate the influence of process variables, AMP emissions and its degradation products. Steadystate simulations were performed using Aspen Plus® V8.4 software to provide a full assessment of the degradation products and their impact on the largescale AMP capture process. The results of the equilibrium model developed in this study revealed that AMP emissions are 3.04E+03mg/Nm3 of CO2 lean flue gas, while the quantity of AMP lost due to degradation was 37.88kg/s for the largescale capture plant. More importantly, the emissions obtained from the PWOD and PWD are 7.80E+03 mg/Nm3 and 9.82E+03 mg/Nm3 of CO2 respectively. Keywords: oxidative degradation, 2amino2methyl1 propanol, emissions, modellin

Evaluation of Emissions of 2-Amino-2-Methyl-1-Propanol Degradation Products by adding Degradation Reactions to the Carbon Dioxide Capture Unit

Degradation is a major problem which poses lots of emission risk during chemical absorption process with amine solvents. Degradation occurs through irreversible side reactions with CO2 and other flue gas components, forming into products that cannot easily regenerate. The degradation products then react with amines to form thermally stable salts, which accumulate in the system over time. The problems associated with degradation include decreased plant equipment life, foaming, corrosion, high solution viscosity, and increased operating cost. Amines capture about 70 90% CO2 from commercial power stations. These high removal rates have many environmental impacts due to their degradation products. Researchers have therefore shown interest in characterising and quantifying atmospheric emissions of amines and their degradation products. In this study, 2Amino2Methyl1Propanol (AMP) degradation reactions were included into a largescale capture plant model to evaluate the influence of process variables, the emissions of AMP and its degradation products. Steadystate simulations were performed using Aspen Plus\uae V8.4 software to provide a full assessment of the degradation products and their impact on the capture process. This assessment is important because it identifies and quantifies all pollutants emitted from the process plant. The results of the simulation indicate that AMP emissions are 3.04E+03mg/N/m3 of CO2 lean flue gas, while the quantity of AMP lost due to degradation was 37.88kg/s for the largescale capture plant. The results further showed that among the gases emitted, ammonia was highest, while acetone was the highest gas formed. In this study, 2amino2methyl1propanol(AMP) degradation reactions were included into a largescale carbon dioxide (CO2) capture plant model to evaluate the influence of process variables, AMP emissions and its degradation products. Steadystate simulations were performed using Aspen Plus\uae V8.4 software to provide a full assessment of the degradation products and their impact on the largescale AMP capture process. The results of the equilibrium model developed in this study revealed that AMP emissions are 3.04E+03mg/N/m3 of CO2 lean flue gas, while the quantity of AMP lost due to degradation was 37.88kg/s for the largescale capture plant. More importantly, the emissions obtained from the PWOD and PWD are 7.80E+03 mg/Nm3 and 9.82E+03 mg/Nm3 of CO2 respectively

Modelling and Simulation of the Batch Hydrolysis of Acetic Anhydride to Produce Acetic Acid

The kinetic modelling of the batch synthesis of acetic acid from acetic anhydride was investigated. The kinetic data of the reaction was obtained by conducting the hydrolysis reaction in a batch reactor. A dynamic model was formulated for this process and simulation was carried out using gPROMS® an advanced process modelling and simulation software. The developed model was validated against experimental data by estimating the kinetic parameter (reaction rate constant k=0.11302 min-1) and comparing simulation results with experimental data. Results obtained show that the formulated model was able to predict the experimental data to a high level of confidence. The dynamic behaviour of the reaction process was assessed by simulating the validated model at the initial state to obtain time trajectories of all the variables of interest. The model developed in this work will provide insight as to how the process responds under dynamic conditions and its amenability to control

Optimization of Bioethanol Production from Cassava Peels

The bioethanol production from waste is acquiring attraction as a strategy for increasing energy security. This study aims to optimize the production of ethanol from cassava peel using Box Bhenken experimental design. The total carbohydrate content of about 90% in cassava peel was subjected to enzymatic hydrolysis using Alpha-amylase followed by Simultaneous Saccharification and Fermentation (SSF) by Saccharomyces cerevisiae for bioethanol production. The production of bioethanol from cassava peels was investigated for 1-4 hours (hydrolysis time), 0.5\u20131.5mg/L (enzyme loading), and 1-5 days (incubation time). A statistical model was developed and validated to predict the yield of bioethanol after fermentation, and the Response Surface Methodology (RSM) was used to optimize the conditions. The results revealed that the maximum ethanol yield of 1.911% was obtained at the optimum hydrolysis time, enzyme loading, and incubation time (i.e. 2.5 hours, 1 mg/L, and 3 days respectively)

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Palm kernels impaction in anorectal malformation: An unusual presentation in an 8-year-old boy

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Thigh-length compression stockings and DVT after stroke

Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease