Search

Absorption and desorption of CO2 into five aqueous tertiary amine solvents and their blends with MAPA were studied using a screening apparatus. Results showed that MAPA significantly enhanced both CO2 absorption rate and absorption capacity. The solvent system with the highest CO2 absorption capacity and cyclic CO2 capacity was 3 M DEEA + 1 M MAPA with a CO2 loading of 2.72 mole CO2/kg solution and a cyclic CO2 capacity of 2.06 mole CO2/kg solution. For both the single and the blended systems, the CO2 absorption capacity decreased when increasing the number of ethanolamine groups on the tertiary amine (DEEA → EDEA → TEA) and when the alkyl chain length in the tertiary amine was increased (EDEA → BDEA). When the alkyl amine group in the tertiary amine became hindered (BDEA → t-BDEA), the CO2 absorption capacity increased. © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) more...

The COVID-19 crisis has identified several weaknesses and shortcomings of global supply chain networks. Due to the rapidly increasing demand of protective healthcare equipment, i.e. goggles, masks or equipment, it is visible that global supply chains have been significantly challenged. Furthermore, countries had to compete for available products, also leading to drastic price rises. The German government had to ask Multinational Companies (MNC) to procure healthcare equipment, as government procurement authorities were not experienced in dealing with global supply chains (Petersen, 2020). Moreover, even though machines for making masks and healthcare equipment are manufactured in Germany, there was no domestic supply. Under pressure to overcome the masks shortage in Germany, the government has promised state subsidies covering 30% of investment costs of companies venturing to launch fabric production. The funding will be capped at €10 million ($10.9 million), but includes a purchase guarantee from the government. The situation displayed how fragile and disruptive global supply chains can be in crisis situations. Moreover, the case shows the dependency on imports from China and other countries for pharmaceuticals or medical equipment. more...

Longitudinal data on the E6/E7 mRNA-based Aptima human papillomavirus (AHPV) assay exceeding three years in comparison to the gold standard Digene Hybrid Capture 2 (HC2) test are not available. We previously reported the cross-sectional data of the German AHPV Screening Trial (GAST) in which 10,040 women were recruited and tested by liquid-based cytology, the HC2 assay, and the AHPV assay., Longitudinal data on the E6/E7 mRNA-based Aptima human papillomavirus (AHPV) assay exceeding three years in comparison to the gold standard Digene Hybrid Capture 2 (HC2) test are not available. We previously reported the cross-sectional data of the German AHPV Screening Trial (GAST) in which 10,040 women were recruited and tested by liquid-based cytology, the HC2 assay, and the AHPV assay. Four hundred eleven test-positive women were followed for up to six years. In addition, 3,295 triple-negative women were screened after a median time of six years. Overall, 28 high-grade cervical intraepithelial neoplasia (CIN3) cases were detected. The absolute risk of developing high-risk HPV-positive CIN3+ over six years among those women that tested negative at baseline was 2.2 (95% confidence interval [95% CI], 1.0 to 4.9) and 3.1 (95% CI, 1.7 to 5.7) per 1,000 women screened by the HC2 and the AHPV tests; the additional risk for those with AHPV-negative compared with HC2-negative results was 0.9 (95% CI, −0.2 to 2.1) per 1,000. In comparison, the absolute risk following a negative LBC test was 9.3 (95% CI, 2.9 to 30.2). The relative sensitivity of AHPV compared to HC2 was 91.5% for CIN3+, and the negative predictive values were 99.8% (95% CI, 99.5 to 99.9%) for HC2 and 99.7% (95% CI, 99.4 to 99.8%) for AHPV. Our data show that the longitudinal performance of the AHPV test over six years is comparable to the performance of the HC2 test and that the absolute risk of CIN3+ over six years following a negative AHPV result in a screening population is low. (This study is registered at ClinicalTrials.gov under registration number NCT02634190.) more...

This study investigates the use of Fourier Transform Near-Infrared (FT-NIR) spectroscopy and Raman spectroscopy to monitor the CO2 absorption process when over 65 wt % concentrated monoethanolamine (MEA) solutions are used. Using high concentrated amines instead of the conventional 30 wt %, is a strategy to decrease the cost of CO2 capture plants by minimizing the energy consumption spent for amine regeneration and reducing the size of the process equipment. In addition, higher solvent concentration has a positive impact on mass transfer. CO2 loading and solvent strength are two main parameters that are used to characterize the well-known CO2 capture process by MEA. Several analytical methods are in practice to determine these two parameters but most of them are timeconsuming and not favourable when quick results are demanded. Process analyzers such as Raman spectroscopy or NIR (Near Infrared) spectroscopy can be used for real-time monitoring of chemical or physical attributes in a system and have advantages over traditional analytical methods. Authors have previously published spectroscopic methods combined with chemometrics to determine CO2 loading in 30 wt % MEA solutions by Raman spectroscopy in laboratory scale and pilot plant experiments. The aim of this paper is to extend these spectroscopic investigations when both the amine concentration and loading are spanned in a range. CO2 loading range was selected between 0- 0.6 mol CO2 / mol MEA and solvent concentration was varied between 66-99.5 wt %. Two analyzers were selected; Raman and Fourier transform near infrared (FT-NIR) spectrometers. It is relatively easy to generate data in a short time by these instruments, however identification of components of a chemical mixture and calibration methods become challenging as the FT-NIR and Raman spectral data are not straightforward. Many spectral responses appear similarly and therefore the choice of chemometrics methods is more reliable than the traditional univariate methods. In this study, chemometrics has been applied for data preprocessing, data exploration and finally for multivariate calibration of four models to predict CO2 loading and MEA concentration from FT-NIR and Raman spectroscopy. more...

On the basis of speciation by nuclear magnetic resonance (NMR) spectroscopy, heat of absorption, and pH data, the reactions occurring in aqueous MAPA (3-(methylamino)propylamine), DEEA (2-(diethylamino)ethanol), and their blend at various carbon dioxide (CO2) loadings were identified and discussed. At increasing CO2 loading, the basicity of the solutions decreased. In the MAPA solvent, this led to the hydrolysis of the carbamate species, which corresponded to a drop in the heat of absorption. In the blend, due to the activity of DEEA, such a drop in both pH and heat of absorption was not noticeable. In the presence of MAPA, in the early loadings DEEA had not yet an influence on the (bi)carbonate formation but mainly on the MAPA activity. However, as soon as the trend for (bi)carbonate formation went as in DEEA singly, the released heat steadily decreased. Both in single and in blended MAPA, the carbamate hydrolyses started at similar pH values, i.e., about 9.8–9.5. more...

Methanol (MeOH) synthesis at low temperature (100 oC) presents an opportunity for full syngas conversion per pass. This presents a cheaper alternative for MeOH synthesis using an air-blown autothermal reformer (ATR) rather than the conventional high temperature (>250 oC) MeOH synthesis approach which requires an expensive cryogenic O2-blown ATR. The aim of this work was to use the process simulation program Aspen HYSYS to simulate and optimize the reactor conditions for a complete MeOH process design using an air-blown ATR. Our results revealed that, while syngas produced from ‘normal’ air-blown ATR (syngas composition 0.20CO:0.40H2:0.39N2) required 100 bar to obtain full conversion per pass, syngas produced from enriched airblown ATR (syngas composition 0.31CO:0.62H2:0.07 N2) required 60 bar total syngas pressure to achieve the same. Even though the energy generated in both processes was enough to cover the heating demand in the total process with surplus, the enriched air-blown system provides a better energy recovery if the surplus energy is not used for extra power generation. The total process energy demand due to compression was estimated to be 2270 and 983 MJ/ton MeOH product for the normal air-blown and enriched air-blown systems respectively. A process design was proposed based on the optimized conditions for the enriched air-blown process. more...

Testing for E6/E7 mRNA in cells infected with high-risk (HR) human papillomavirus (HPV) might improve the specificity of HPV testing for the identification of cervical precancerous lesions. Here we compared the RNA-based Aptima HPV (AHPV) assay (Hologic) and the DNA-based Hybrid Capture 2 (HC2) HPV test (Qiagen) to liquid-based cytology (LBC) for women undergoing routine cervical screening. A total of 10,040 women, 30 to 60 years of age, were invited to participate in the study, 9,451 of whom were included in the analysis. Specimens were tested centrally by LBC, the AHPV test, and the HC2 test, and women who tested positive on any test were referred for colposcopy. Genotyping was performed on all HR-HPV-positive samples. Test characteristics were calculated based on histological review. As a result, we identified 90 women with cervical intraepithelial neoplasia grade 2+ (CIN2+), including 43 women with CIN3+. Sensitivity differences between the AHPV test and the HC2 test in detecting CIN2+ ( P = 0.180) or CIN3+ ( P = 0.0625) lesions were statistically nonsignificant. Of three CIN3 cases that were missed with the AHPV test, two cases presented lesion-free cones and one had a non-HR HPV67 infection. The specificity (P < 0.001) than those of the HC2 test. The overall agreement between the tests was substantial (κ = 0.77). Finally, we present results for several possible triage strategies, based on the primary screening test being either the AHPV test or the HC2 test. In summary, the AHPV assay is both specific and sensitive for the detection of high-grade precancerous lesions and may be used in primary cervical cancer screening for women ≥30 years of age. more...