Post-Combustion Carbon Capture
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Post-Combustion Carbon Capture
Post-combustion carbon capture means capturing CO2 from the flue gas of power plants in order to significantly reduce the power plants’ CO2 emissions.
Siemens has developed a proprietary absorption process for post-combustion carbon dioxide capture (called Siemens PostCapTM) which is applicable to coal-fired power stations and natural gas-fired power plants. PostCapTM can be integrated in new power plants, but could also be retrofitted to existing power plants at small, medium or large scale.
Furthermore, there is the possibility to design new power plants “capture ready" in order to enable or facilitate a later cost-effective retrofit with a post-combustion carbon capture plant.
Siemens has all required major technologies available (power plants and turbines, CO2 capture, CO2 compression and drives / automation elements for transport and injection), to offer CO2 capture as an optimized package solution.
The captured CO2 can either be used in the industry (oil and gas industry for enhanced oil recovery or in the chemical industry for production of other chemicals e.g. methan/methanol) or stored in geological formations.
Siemens has developed a proprietary absorption process for post-combustion carbon capture, called PostCapTM. It based on a special solvent (amino acid salt solution) which is capable of separating at least 90% of the CO2 contained in the flue gas from fossil power plants. A pilot plant at E.ON's coal-fired power plant Staudinger, Germany, has been operated by Siemens since August 2009 on flue gases of this power plant and has been upgraded to flue gases from natural gas-fired power stations in 2012 to validate the technology. Drawing on the results of this pilot project, Siemens can offer PostCapTM for large-scale projects. PostCapTM is suitable for new fossil-fired power plants and for retrofitting existing power plants.
In comparison with first-generation processes, e.g. the monoethanol-amine process (MEA), PostCapTM has some decisive advantages regarding environmental friendliness as well as investment and operating costs. One is the non-volatile character of the solvent. The process is suitable for coal-, lignite- and natural-gas fired power plants.The PostCapTM process is characterized by an environmentally friendly solvent, minimal detectable solvent emissions, good solvent stability (in particular against oxygen), low energy consumption and ease of handling by power plant operators and personnel.
Your benefits with Siemens´competencies:
Feasibility and Front-End Engineering Design (FEED) studies including process simulations can be executed to a develop power-plant specific process design, cost estimation for the carbon capture plant and information about the requirements for integrating the process into the power plant. The documents and information obtained in the studies provide the basis for further investment decisions.
For implementation of capture projects Siemens would deliver a Process Design Package covering all fields of engineering and HSE in such a way that experienced EPC-contractor can continue with detail engineering, procurement and installation of the capture plant and its utilities.
Siemens relies on powerful in-house capacities for engineering and project implementation ranging from products like gas turbines and compressors over large package units in the oil and gas and power plant industries up to turnkey solutions for power plants. Furthermore Siemens has broad expertise in chemical process engineering. Siemens leverages these competencies to provide customized solutions for the implementation of Siemems PostCapTM.
The following table shows a selection of major projects:
|Technology Qualification Program (TQP) of CO2 post-combustion capture technologies: Pre-commercial procurement of a CO2 capture plant at Mongstad Refinery (approx. 1.2 Mio tpa CO2): The TQP was divided into three phases:
1. Feasibility study to show that the technology can be used at Mongstad
2. Demonstrate process operation and specified emissions level/criteria
3. Concept Phase for design of full-scale CO2 capture
|Masdar CCS project||Masdar,
|Front End Engineering & Design (FEED) Study for a PostCap™ plant to capture approx. 1.8 Mio tpa CO2 for enhanced oil recovery (EOR).||2011-2012|
|US pilot plant||Department of Energy, USA||Basic Engineering for 2.5 MWel slip stream pilot plant at a coal-fired power station in the USA; 2,100 kg/h of captured CO2||2010-2011|
|Statkraft Capture Ready||Statkraft, Norway||Engineering Study: adaptation of PostCapTM process to combined cycle conditions, evaluation of capture ready measures in the power plant and of overall plant performance with CO2 capture, evaluation of the dynamic behaviour of a combined cycle with CO2 capture.||2009-2010|
|Maasvlakte ROAD Project||E.ON and GDF Suez||Feasibility study for 1.1 Mio tpa CO2 at E.ON coal-fired power station Maasvlakte in the Netherlands||2010|
|EON PostCapTM pilot plant||E.ON / German Government (BMWi)||Pilot plant at a E.ON's coal-fired Staudinger power station in Germany; capture of approx. 1 t CO2/d; capture rate > 90 %.||operating since 2009|
|Reference power plant||Siemens||Internal Study: Development of an 800 MW reference coal power plant with PostCap CCS; approx. 12,000 t/d.||2009|
|CCS 50+ Wilhelmshaven||E.ON, Germany||Study, including e.g. Process Description, PFD, Equipment List, Cost Estimate, Schedule and Investment Plan.||2009|
|FINNCAP, Meri-Pori||Fortum||Siemens selected as vendor for FEED and EPC, before Fortum decided to leave business. Investigations included e.g. process description, PFD, layout concept, etc.||2009|
|POSTCAP||Siemens||Siemens Research and Development Program "PostCapTM" funded by the German Ministry of Economy and Technology (BMWi) and E.ON.||2007-2012|
Due to uncertainties about the general conditions for introducing CCS technologies, future retrofitting of existing power plants is currently the preferred solution. New built fossil-fired power plants should be ready for the incorporation of a carbon capture plant at a later date with minimal cost impact at the time of constructing the power plant, i.e. they should be "capture ready". Capture ready design and suitable retrofit solutions can be realized easier for post-combustion capture technology than for other carbon capture options like Oxyfuel and Pre-combustion.
According to the EU Directive 2009/31/EC in place since 2009, fossil power plants rated above 300 MW that are intended for new construction are subject to evaluation of their "capture ready design" to ensure that they meet the technical and feasibility requirements for subsequent retrofitting of CO2 capture technology. Siemens has defined capture-ready measures and offers solutions for power plants in capture ready design based on its broad experiences in power plant business.
Capture ready assessments include:
The installation and operation of the Siemens PostCapTM pilot plant at the hard coal fired Staudinger power station near Frankfurt, Germany was realized in collaboration with the power station operating company E.ON and co-funded by German Federal Ministry for Economic Affairs and Energy (BMWi). The whole workflow comprising plant design, piping (3D-modelling), instrumentation and control strategy, process automation, coupling to power plant, hazard and operability study (HazOp), authority engineering and construction site supervision was carried out by Siemens.
The onsite piloting facility is able to process flue gas from the coal fired plant as well as from a separate gas fired plant. The pilot plant is equipped with more than 150 sensors, it is fully automated and operable via remote access. Additional features are online analytics for the components CO2, O2, SO2 and NOx, several materials sampling mountings and devices for isokinetic emission measurement.
Its design was based on the data and experiences gained from a fully automated lab plant situated in the Siemens' laboratories at the Industrial Park Hoechst close to Frankfurt, Germany.
The main components in the CO2 capture pilot plant are the absorption and desorption columns with additional equipment for energy saving, e.g. Lean Solvent Flash. Because of pilot plant sizing, the flue gas cooler and the absorber could be combined in one column, however the liquid cycles are strictly separated.
One of the most important aims was to gain operational experience with real flue gas under real outdoor conditions. Currently more than 9000 operating hours demonstrated the operability of the pilot plant and the chosen solvent (Amino Acid Salt formulation). The effects of power plant start-ups and shut-downs could be examined and described by dynamic simulation. Troubleshooting cases could be practiced. The know-how which was collected led to improvements of the pilot plant and was incorporated into design specifications for full scale plants. During the whole pilot operation, no plugging of trays or packings was observed.
The absorber and desorber column internals in particular are essential for the efficient and reliable operation of the carbon capture plant. The packing type and height used in the pilot plant is equal to the packing of the full-scale plant. Thus, the scalability of lab scaled trials could be shown. The following table summarizes the figures of the lab and pilot facility.
|Lab scale||Pilot scale|
|Absorber||Diameter||50 mm||DN 200|
|Desorber||Diameter||50 mm||DN 150|
|Scale-Up Factor||Cross-Section Area Absorber||-||16 x
|CO2 amount captured (capture rate 90 %)||coal fired||kg/h||0.72||54|
|CO2 amount captured (capture rate 90 %)||gas fired||kg/h||0.22||16.2|
Further results of the pilot phase were the validation of the process model with real life flue gas. Reliable information were gained towards:
All these experiences are leading to a continuous improvement of the Siemens PostCapTM technology.