Decarbonizing the Coal-Fired Power Sector in China via Carbon Capture, Geological Utilization, and Storage Technology.

Carbon capture, utilization, and storage (CCUS) is a critical technology to realize carbon neutrality target in the Chinese coal-fired power sector, which emitted 3.7 billion tonnes of carbon dioxide in 2017. However, CCUS technology is often viewed as an "alternative technology" option owing to common perceptions of relatively high cost and potential risks. This study indicates that coal power CCUS is likely to be a cost-effective and key technology for helping China reach the ambitious goal of carbon neutrality. This comprehensive, national-scale assessment of CCUS deployment on coal power in China is based on a unique bottom-up approach that includes site selection, coal plant screening, techno-economic analysis, and carbon dioxide source-sink matching. Analysis indicates that, based on 2017 costs and assumptions, more than 70% of coal power plants in this study could be cost-competitive with natural gas-fired power plants, and 22-58% would be cost-competitive with onshore wind generation. These insights suggest that the commercialization of CCUS technology in the coal power sector in China is a viable route toward decarbonizing the economy if a grid price policy similar to that of renewables and natural gas power is applied.

Updated Hourly Emissions Factors for Chinese Power Plants Showing the Impact of Widespread Ultralow Emissions Technology Deployment.

Nationwide severe air pollution has prompted China to mandate the adoption of ultralow emissions (ULE) control technologies at all of its coal-fired power plants by 2020. This process has accelerated greatly since 2014 and, combined with operational adjustments related to overcapacity, has reduced the emissions of nitrogen oxides (NO x), sulfur dioxide (SO2), and particulate matter (PM). Yet the quantitative understanding of ULE benefits is poor. Using detailed emissions data from 38 units at 17 power plants, corresponding to 10 combinations of ULE technologies representative of the Chinese power sector, we show that emissions factors for NO x, SO2, and PM are up to 1-2 orders of magnitude lower after ULE retrofitting. The effectiveness in cutting emissions shows a large spread across the various ULE technology combinations, providing an opportunity to choose the most efficient, economically viable technology (or a combination of technologies) in the future. The temporal variations in emissions at hourly resolution reveal the effects of power plant load on emissions, an increasingly important factor given that power plants are not operated at full capacity. These data will be useful in efforts to understand the evolving state of air quality in China and can also provide a basis for benchmarking state-of-the-art air pollution control equipment globally.

Patterned nanorod arrays produced from hydrophobically masked templates.

A simple method to mask hydrophobically porous templates for patterned nanorod growth is described. Patterning was achieved by treating the template with an alkylsilane to render the pores hydrophobic, followed by irradiation with UV light to selectively degrade the alkyl siloxyl coating in the illuminated regions to produce a template with both hydrophobic and hydrophilic pores. Patterned arrays comprising a single metallic composition and multiple metallic compositions were electrodeposited in the hydrophobically masked template.

Electric-field-induced orientation of surfactant-templated nanoscopic silica.

While exhibiting a well-defined nanometer-level structure, surfactant-templated nanoscopic silicas produced via self-assembly do not always possess long-range order. We demonstrate that long-range order can be controlled by guiding the self-assembly of nanostructured silica-surfactant hybrids with low-strength electric fields (E approximately 200 V/m) to produce nanoscopic silica with both the micrometer- and nanometer-level structures oriented parallel to the applied field. Under the influence of the electric field, nanoscopic silica particles migrate, elongate, and merge into fibers with a rate of migration proportional to the applied field strength. The linear dependence with the field strength indicates that the process is governed by electroosmotic flow but not by polarization effects. Realignment of the short-range ordered surfactant nanochannels along the fiber axis accompanies the migration.

Evidence of ion transport through surface conduction in alkylsilane-functionalized nanoporous ceramic membranes.

Alkylsilane-modified nanoporous ceramic membranes exclude water from their pores yet exhibit transmembrane electrical conductivity in aqueous electrolyte solutions. That effect was studied using impedance spectroscopy and (29)Si NMR. Anodic aluminum oxide membranes with alkylsilane-functionalized pores exhibited a transmembrane electrical resistance that increased with the length of the hydrocarbon chain. Microstructural studies revealed that the conduction was due primarily to a small number of "hydrophilically defective" pores in membranes modified by long-chain alkylsilanes and both hydrophilic defects and surface conduction in pores modified by short-chain alkylsilanes. Hydroxyl groups in short-chain alkylsilane layers act as "water wires" to enable surface ion transport. The local concentration of hydroxyl groups decreased with alkylsilane chain length, explaining the resistance trend. This constitutes the first direct evidence that alkylsilane functionalization affects electrical as well as wetting properties.

Mesoporous silica composites containing multiple regions with distinct pore size and complex pore organization.

Porous ceramics are of great interest for filtration, catalysis, and reactive separation processes. Performance in these applications is highly dependent on features such as pore size distribution and connectivity and wall composition. Here, we describe a method allowing the rational design and synthesis of mesoporous silica composites with controlled heterogeneous pore architectures and demonstrate its validity by producing structures with predetermined placement of regions having different pore size and pore organization.