Zero-Emission Cement Plants with Advanced Amine-Based CO2 Capture.

Decarbonization of the cement sector is essentially required to achieve carbon neutrality to combat climate change. Amine-based CO2 capture is a leading and practical technology to deeply remove CO2 from the cement industry, owing to its high retrofittability to existing cement plants and extensive engineering experience in industrial flue gas decarbonization. While research efforts have been made to achieve low-carbon cement with 90% CO2 removal, a net-zero-emission cement plant that will be required for a carbon neutrality society has not yet been investigated. The present study proposed an advanced amine-based CO2 capture system integrated with a cement plant to achieve net-zero CO2 emission by pushing the CO2 capture efficiency to 99.7%. Monoethanomaine (MEA) and piperazine/2-amino-2-methyl-1-propanol (PZ-AMP) amine systems, which are considered to be the first- and second-generation capture agents, respectively, were detailed investigated to deeply decarbonize the cement plant. Compared to MEA, the advanced PZ-AMP system exhibited excellent energy performance with a regeneration duty of ∼2.6 GJ/tonne CO2 at 99.7% capture, 39% lower than the MEA process. This enabled a low CO2 avoided cost of $72.0/tonne CO2, which was 18% lower than that of the MEA-based zero-emission process and even 16.2% lower than the standard 90% MEA process. Sensitivity analysis revealed that the zero-emission capture cost of the PZ-AMP system would be further reduced to below $56/tonne CO2 at a $4/GJ steam production cost, indicating its economic competitiveness among various CO2 capture technologies to achieve a zero-emission cement plant.

NO production of granulocytes associated with antibacterial immune response in Tegillarca granosa.

Nitric oxide (NO) is a signaling molecule and immune effector produced by the nitric oxide synthases (NOS), which involved to various physiological processes of animals. In marine bivalves, hemocytes play important roles in antimicrobial innate immune response. Although hemocyte-derived NO has been detected in several bivalves, the immune function of hemocyte-derived NO is not well understood. Here, we investigated the antibacterial response of hemocyte-derived NO in the blood clam Tegillarca granosa. Two types of hemocytes including erythrocytes and granulocytes were isolated by Percoll density gradient centrifugation, their NO production and TgNOS expression level were analyzed. The results showed that NO was mainly produced in granulocytes and almost no detected in erythrocytes. The granulocytes showed significantly higher NO level and TgNOS expression level than the erythrocytes. And the TgNOS expression level was significantly increased in granulocytes after Vibro parahemolyticus challenge. In addition, the NO donor sodium nitroprusside (SNP) significantly increased the NO production of hemocytes to kill pathogenic bacteria. In summary, the results revealed that granulocytes-derived NO play vital roles in the antimicrobial immune response of the blood clam.

Implicit Task-Driven Probability Discrepancy Measure for Unsupervised Domain Adaptation.

Probability discrepancy measure is a fundamental construct for numerous machine learning models such as weakly supervised learning and generative modeling. However, most measures overlook the fact that the distributions are not the end-product of learning, but are the input of a downstream predictor. Therefore, it is important to warp the probability discrepancy measure towards the end tasks, and towards this goal, we propose a new bi-level optimization based approach so that the two distributions are compared not uniformly against the entire hypothesis space, but only with respect to the optimal predictor for the downstream end task. When applied to margin disparity discrepancy and contrastive domain discrepancy, our method significantly improves the performance in unsupervised domain adaptation, and enjoys a much more principled training process.

Achieving Zero/Negative-Emissions Coal-Fired Power Plants Using Amine-Based Postcombustion CO2 Capture Technology and Biomass Cocombustion.

The strengthening carbon mitigation efforts to meet the 1.5 °C target requires the development of zero/negative CO2 emission technologies to eliminate large direct CO2 emissions from fossil-fuel fired power stations. Amine scrubbing is a dominant technology to capture CO2 from fossil-fuel power stations, but its application in achieving zero/negative emission in power stations is rarely reported. The present study investigates the MEA-based technologies to achieve zero and negative CO2 emission in coal-fired power stations, and their techno-economic performance was evaluated in detail. These zero/negative-emission technologies include 99.7% CO2 capture from flue gas (zero emission), biomass cocombustion with coal integrated with CO2 capture at ratios of 10% biomass/90% CO2 capture and 5% biomass/95% CO2 capture (zero-emission), and 10% biomass/95% CO2 capture for negative-emission power station. Our investigation revealed that these zero/negative-emission technologies are technically and economically viable, and their CO2 avoided costs did not significantly increase compared to the standard 90% CO2 capture. The CO2 avoided cost for 99.7%-capture is estimated at $66.5/tonne CO2, which is $2.6/tonne CO2 higher than that of 90%-capture. The biomass cocombustion zero/negative-emission technologies show better economic performance with CO2 avoided cost of $64.1-64.8/tonne CO2, which is only $0.2-0.7/tonne CO2 higher than the standard 90%-capture. These results indicate that the amine-based CO2 capture integrated with biomass cocombustion technology would be economically competitive to achieve zero or even negative CO2 emissions in coal-fired power stations.

Mechanism Investigation of Advanced Metal-Ion-Mediated Amine Regeneration: A Novel Pathway to Reducing CO2 Reaction Enthalpy in Amine-Based CO2 Capture.

The high energy consumption of CO2 and absorbent regeneration is one of the most critical challenges facing commercial application of amine-based postcombustion CO2 capture. Here, we report a novel approach of metal-ion-mediated amine regeneration (MMAR) to advance the process of amine regeneration. MMAR uses the dual ability of amine to reversibly react with CO2 and reversibly complex with metal ions to reduce the enthalpy of the CO2 reaction, thus decrease the overall heat requirement for amine regeneration. To elucidate the mechanistic effects behind MMAR's ability to reduce CO2 reaction enthalpy, we developed a comprehensive chemical model describing the chemistry of Me(II)-monoethanolamine(MEA)-CO2-H2O system. The model was then validated using experimentally determined CO2 partial pressures via vapor-liquid equilibrium (VLE) measurements. We used the validated chemical model to gain insight into VLE behavior and solution chemistry, and to identify the specific changes in CO2 reaction enthalpy with and without metal ions. Two metals and five amines were evaluated in detail, which revealed that metal-ions with high complexation enthalpy and amines with large carbamate stability constant are preferred in MMAR, owing to their large reduction in reaction enthalpy and regeneration duty. We anticipate that MMAR could provide an alternative pathway to reducing the energy consumption of absorbent regeneration, ultimately making amine-based processes more technically and economically viable.

Information Derivation from Vapor-Liquid Equilibria Data: A Simple Shortcut to Evaluate the Energy Performance in an Amine-Based Postcombustion CO2 Capture.

Evaluation of amine absorbents is crucial for the development of a technically and economically feasible CO2 capture process. However, the capture performance estimation usually requires a load of experiments, which is time-consuming and labor-intensive. The present study proposed a simple but effective shortcut that employs the fewest experimental data, i.e., vapor-liquid equilibria (VLE) data only, to estimate the CO2 capture performance by developing a validated chemical VLE model and a simple shortcut approach. The reliability of the proposed method was validated by the excellent agreement with the results from the laboratory and pilot plant experiments, and rigorous rate-based MEA model in Aspen Plus. We demonstrated that this approach can reliably predict the important capture performance indicators, such as CO2 solubility, heat of CO2 reaction, lean/rich CO2 loadings and heat requirement of absorbent regeneration. Moreover, this shortcut approach can provide guidance for process modification to achieve the minimum regeneration energy. The extended application of this approach to other amines, i.e., piperazine (PZ), 2-amino-2-methyl-1-propanol (AMP), and blended PZ and AMP (PZ/AMP), also showed the good consistency with the published experimental and simulation results, further indicating the reliability of the shortcut approach to estimate the energy performance of amine processes. It is anticipated that the proposed method would simplify the evaluation of CO2 capture performance using VLE data only, providing an efficient and effective shortcut for screening and evaluating amine-based CO2 capture.

The recycling of Mn-Zn ferrite wastes through a hydrometallurgical route.

A novel recycling route using acid leaching, reduction, purification, co-precipitation and traditional ceramic process was applied to process the Mn-Zn ferrite wastes and prepare the corresponding high permeability soft magnetic product. Above 95% of Fe, Mn, Zn in the waste materials could be recycled in the form of Mn-Zn ferrite products through the hydrometallurgical route. The comprehensive properties of Mn-Zn ferrite prepared from wastes by this route have broader frequency characteristics, higher resistivity, lower loss coefficient and temperature coefficient as compared to the A102 product (Acme Electronics Corporation, Taiwan). Moreover, the cost of this recycling technology has economical advantage over the traditional ceramic process, which holds a promising industrial application.