Part Load Behaviour of Power Plants with a Retrofitted Post-combustion CO2 Capture Process

AbstractThe flexible and part load operation of fossil-fuelled power plants will increase due to the higher share of fluctuating renewable energies, like wind and solar power. In this work the part load behaviour of the post-combustion CO2 capture (PCC) process is evaluated. The net efficiency of the conventional hard-coal-fired power plant decreases from 45.6% at full load to 41.5% at 40% load. The net efficiency with PCC using 7 m MEA (monoethanolamine) as solvent decreases to 34.8% at full load and to 30.1% at 40% load. The pressure of the intermediate pressure/low pressure crossover section has major influence on the efficiency. In part load higher pressures are in advantage due to lower throttling losses. The shutdown of the PCC is a possibility to generate balancing power. A reduced capture rate of 75% leads to a generation of 5% additional power

Internet based multicenter study for thoracolumbar injuries: a new concept and preliminary results

This article reports about the internet based, second multicenter study (MCS II) of the spine study group (AG WS) of the German trauma association (DGU). It represents a continuation of the first study conducted between the years 1994 and 1996 (MCS I). For the purpose of one common, centralised data capture methodology, a newly developed internet-based data collection system ( http://www.memdoc.org ) of the Institute for Evaluative Research in Orthopaedic Surgery of the University of Bern was used. The aim of this first publication on the MCS II was to describe in detail the new method of data collection and the structure of the developed data base system, via internet. The goal of the study was the assessment of the current state of treatment for fresh traumatic injuries of the thoracolumbar spine in the German speaking part of Europe. For that reason, we intended to collect large number of cases and representative, valid information about the radiographic, clinical and subjective treatment outcomes. Thanks to the new study design of MCS II, not only the common surgical treatment concepts, but also the new and constantly broadening spectrum of spine surgery, i.e. vertebro-/kyphoplasty, computer assisted surgery and navigation, minimal-invasive, and endoscopic techniques, documented and evaluated. We present a first statistical overview and preliminary analysis of 18 centers from Germany and Austria that participated in MCS II. A real time data capture at source was made possible by the constant availability of the data collection system via internet access. Following the principle of an application service provider, software, questionnaires and validation routines are located on a central server, which is accessed from the periphery (hospitals) by means of standard Internet browsers. By that, costly and time consuming software installation and maintenance of local data repositories are avoided and, more importantly, cumbersome migration of data into one integrated database becomes obsolete. Finally, this set-up also replaces traditional systems wherein paper questionnaires were mailed to the central study office and entered by hand whereby incomplete or incorrect forms always represent a resource consuming problem and source of error. With the new study concept and the expanded inclusion criteria of MCS II 1, 251 case histories with admission and surgical data were collected. This remarkable number of interventions documented during 24 months represents an increase of 183% compared to the previously conducted MCS I. The concept and technical feasibility of the MEMdoc data collection system was proven, as the participants of the MCS II succeeded in collecting data ever published on the largest series of patients with spinal injuries treated within a 2 year period

Identification of common genetic risk variants for autism spectrum disorder

Autism spectrum disorder (ASD) is a highly heritable and heterogeneous group of neurodevelopmental phenotypes diagnosed in more than 1% of children. Common genetic variants contribute substantially to ASD susceptibility, but to date no individual variants have been robustly associated with ASD. With a marked sample-size increase from a unique Danish population resource, we report a genome-wide association meta-analysis of 18,381 individuals with ASD and 27,969 controls that identified five genome-wide-significant loci. Leveraging GWAS results from three phenotypes with significantly overlapping genetic architectures (schizophrenia, major depression, and educational attainment), we identified seven additional loci shared with other traits at equally strict significance levels. Dissecting the polygenic architecture, we found both quantitative and qualitative polygenic heterogeneity across ASD subtypes. These results highlight biological insights, particularly relating to neuronal function and corticogenesis, and establish that GWAS performed at scale will be much more productive in the near term in ASD

Part load behaviour of power plants with a retrofitted post-combustion CO₂ capture process

The flexible and part load operation of fossil-fuelled power plants will increase due to the higher share of fluctuating renewable energies, like wind and solar power. In this work the part load behaviour of the post-combustion CO₂ capture (PCC) process is evaluated. The net efficiency of the conventional hard-coal-fired power plant decreases from 45.6% at full load to 41.5% at 40% load. The net efficiency with PCC using 7 m MEA (monoethanolamine) as solvent decreases to 34.8% at full load and to 30.1% at 40% load. The pressure of the intermediate pressure/low pressure crossover section has major influence on the efficiency. In part load higher pressures are in advantage due to lower throttling losses. The shutdown of the PCC is a possibility to generate balancing power. A reduced capture rate of 75% leads to a generation of 5% additional power.Bundesministerium für Wirtschaft und Technologi

Evaluation and comparison of the part load behaviour of the CO₂ capture technologies oxyfuel and post-combustion

The rising share of fluctuating renewable energies increasingly demand flexible and part load operation of fossil-fuelled power plants with and without CCS. In this work the part load behaviour of the Oxyfuel and the post-combustion CO₂capture processes are evaluated and compared. The net efficiency of the conventional hard-coal-fired power plant decreases from 45.2% at full load to 41.6% at 40% load. The net efficiency with post-combustion CO₂capture using 7 m MEA as solvent decreases to 34.7% at full load and 30.2% at 40% load. The Oxyfuel process reaches in turn a net efficiency of 36.6% at full load and 32.3% at 40% load and shows therefore a benefit of 1.9%-points at full load compared to the postcombustion CO₂capture with MEA. The efficiency advantage of the Oxyfuel process compared to the post-combustion CO₂capture process remains constant at part load.Bundesministerium für Wirtschaft und Energi

Evaluation and Comparison of the Part Load Behaviour of the CO2 Capture Technologies Oxyfuel and Post-Combustion

AbstractThe rising share of fluctuating renewable energies increasingly demand flexible and part load operation of fossil-fuelled power plants with and without CCS. In this work the part load behaviour of the Oxyfuel and the post-combustion CO2 capture processes are evaluated and compared. The net efficiency of the conventional hard-coal-fired power plant decreases from 45.2% at full load to 41.6% at 40% load. The net efficiency with post-combustion CO2 capture using 7 m MEA as solvent decreases to 34.7% at full load and 30.2% at 40% load. The Oxyfuel process reaches in turn a net efficiency of 36.6% at full load and 32.3% at 40% load and shows therefore a benefit of 1.9%-points at full load compared to the post- combustion CO2 capture with MEA. The efficiency advantage of the Oxyfuel process compared to the post-combustion CO2 capture process remains constant at part load

Energetic evaluation of different flow sheet modifications of post-combustion CO₂ capture plant at coal and natural gas fired power plant for a generic improved solvent

The post-combustion capture (PCC) technology is a promising possibility to reduce CO₂ emissions of fossil fuel fired power plants. One of the main concerns for the PCC is the loss in electric power output. A reduction in efficiency penalty for solvent based PCC can be achieved by improving the solvent properties as well as by improving the process design. There are many different process flow sheet modifications with an improvement in process design reported in literature. In this work two of these modifications for a capture plant are evaluated. To be able to compare these process modifications it is necessary to evaluate them on identical solvent and process conditions. The modified processes are compared to base cases processing the flue gas from a supercritical pulverised coal fired power plant as well as a natural gas combined cycle power plant. The solvent used in the capture plant is a generic improved solvent, representing possible future solvents. The main advantages of the flow sheet modifications are pointed out. Subsequent, the specific reboiler heat duty, the specific cooling duty and the specific auxiliary power for the capture plant are shown for the flow sheet modifications. The overall efficiency penalties for the flow sheet modifications are compared and differences are highlighted