7 th International Exergy, Energy and Environment Symposium 27 th April 2015 Experimental results of Split-Flow Modification for Post-Combustion CO 2 Capture Process Marcin Stec, Institute for Chemical Processing of Coal mstec@ichpw.pl
Clean Coal Technology Centre, Zabrze, Poland Clean Coal Technology Centre Institute for Chemical Processing of Coal 2/20
Clean Coal Technology Centre, Zabrze, Poland Pressurized gasification and oxy-combustion in circulating fluidized bed Biomass gasification Solid fuels drying Coking of coal Chemical looping reactor 3/20
CO 2 Capture Process Developement Unit Descritption Specification Process: chemical absorption Gas source: flue gases or mixtures or technical gases Gas flow: 20-100 m 3 n/h Solvent: aqueous amine solution Solvent flow: to 750 dm 3 /h Columns height: 7m Equipement: 34 devices 4/20
Process flow diagram Activated coal SO x adsorber Water wash section Solvent heat exchangers Stripper Condeser for water removal Direct contact cooler, Dedusting Gas saturation, CO 2 absorption sections Evaporator 5/20
Structured and random packing description Cylindrical ring 5mm VFF GmbH 1400mm Sulzer CY 320mm Sulzer CY 480mm Berl saddles 10mm VFF GmbH 1200mm Interpack #2 VFF GmbH 1600mm Novalox saddles ½ VFF GmbH 2000mm 6/20 Columns diameter: 273mm Interpack #1 VFF GmbH 1000mm
Experimental SCADA Supervisory Control And Data Acquisition 7/20
Results and discussion Nomenclature Parameter Description Unit Solvent loading concentration of CO 2 that a solvent contains CO 2 recovery Reboiler heat duty Typical values: 0,2 0,5 Amount of CO 2 captured divided by amount of CO 2 in flue gas Typical values: 80 90 Energy delivered to the process divided by amount of CO 2 captured Typical values: 3 6 % 8/20
Results and discussion Stream splitting - motivation Because of semi-lean amine drawn off the middle of the stripper, the amount of the solvent remaining in the stripper for further regeneration is lower, therefore it can be regenerated to a higher extent than for conventional process. Resulting lean amine is very clean and can be fed to the top of the absorber to polish the gas Lean amine Low loading Semi-Lean amine Average loading Semi-lean amine recycled to an intermediate stage of the absorber is used to absorb the bulk of CO 2. Additionally semi-lean amine, which is cooled before being fed to the column, suits as interstage absorber cooling. 9/20
Results and discussion Rich split - motivation One of the streams of the lean amine is routed directly to the amine stripper bypassing heat exchangers. This stream is heated by condensing steam in the column which would normally be lost from the stripper. Reducing the losses of the steam and heating of a portion of amine reduces the overall energy requirements of the process. Rich amine High loading 10/20
Results and discussion Gas conditions at the absorber inlet Case Process variable 1 2 3 Standard Split-flow Standard Conditions Reboiler heating power (kw) Volumetric flow (m 3 /h) Mass flow (kg/h) Pressure (kpa) Temperature ( C) Composition (vol % - dry) Nitrogen 87.7 Carbon dioxide 12.3 4 Split-flow 33.0 33.0 29.7 29.7 94.4 94.4 92.9 92.9 126.3 126.3 124.2 124.2 34.8 38.6 38.3 38.1 17.3 15.4 15.2 15.2 11/20
Results and discussion Operating conditions Process variable CO 2 recovery (%) Reboiler Heat Duty (MJ/kg CO2 ) Absorber pressure (kpa) Stripper pressure (kpa) L/G (kg/kg) Overall rich amine mass flow (kg/h) Rich amine mass flow top stripper inlet (kg/h) Rich amine mass flow middle stripper inlet (kg/h) Rich amine mass flow bottom stripper inlet (kg/h) Lean amine mass flow (kg/h) Semi-lean amine mass flow (kg/h) 1 Standard 2 Split-flow Case 3 Standard 4 Split- flow 91.1 92.5 91.8 93.0 5.25 5.05 4.74 4.46 29.99 29.99 29.98 30.00 45.02 45.01 44.99 44.98 5.20 5.22 5.31 5.32 694.9 685.3 694.3 693.3 60.5 60.5 60.6 60.6 19.5 267.0 16.7 274.8 614.9 357.7 617.0 357.9 656.7 323.8 659.7 324.4-335.5-336.3 Slight increase in CO 2 recovery Reduction of the reboiler heat duty by 4% and 6% Constant process parameters Streams splitted fifty-fifty 12/20
Result and discussion Solvent loading Higher loading in absorber Process variable Rich amine loading (mol CO2 /mol MEA ) Lean amine loading (mol CO2 /mol MEA ) Semi-lean amine loading (mol CO2 /mol MEA ) 1 Standard 2 Split-flow Case 3 Standard 4 Split-flow 0.411 0.420 0.427 0.423 0.273 0.234 0.296 0.240-0.329-0.336 Deeper regeneration of the solvent 13/20
Results and discussion Absorber operating lines Similar driving force of absorption in the lower part of the absorber High driving force of absorption in the upper part of the absorber 14/20
Results and discussion Absorber temperature profile Lean amine inlet Semi-lean amine inlet Lower temperature below semi-lean amine inlet Intercooling effect 15/20
Results and discussion Pros and cons of the stream-splitting Higher CO 2 recovery Lower reboiler heat duty Higher CAPEX and OPEX due to additional piping and equipement (pumps) 16/20
Results and discussion Economic anaylsis The full chain CCS demonstration plant, captures and stores the CO 2 from 250MW of net electricity generation, with 100km CO 2 pipeline, solvent: 30 wt% MEA, CO 2 recovery: min. 90% Split-stream flow sheet CAPEX: PLN 1000.3M OPEX: PLN 159.7M / year Standard flow sheet CAPEX: PLN 978.2M OPEX: PLN 155.7M / year How long will it take a split-stream CCS plant to pay for itself? CAPEX difference (PLN 22.1M) will be paid in less then 6 years! 17/20
Summary The reduction in the reboiler heat duty for split-flow process during trials presented in this paper ranges from 4 to 6%. Apart from the reboiler heat duty reduction, the increase in CO 2 recovery is also observed with split-flow designs. Split-flow process improvement proved its value during experimental tests because with minor increase in process complexity, noticeable increase in process efficiency was perceived. It can be expected that split flow modification coupled with new solvent would drastically decrease the energy demand and increase the CO 2 recovery of the amine-based postcombustion CO 2 capture process. 18/20
Institute for Chemical Processing of Coal On another occasion Results from the Amine-based CO 2 Capture Pilot Plant We invite you to take a virtual tour of the Clean Coal Technology Centre: http://ichpw.wkraj.pl/#/65563/0 and to watch the movie about the Insitute: http://koala.ichpw.zabrze.pl/video/institute_for_ Chemical_Processing_of_Coal.mp4 19/20
The results presented in this paper were obtained during research co-financed by the National Centre of Research and Development within the framework of Contract SP/E/1/67484/10 Strategic Research Programme Advanced technologies for energy generation: Development of a technology for highly efficient zero-emission coal-fired power units integrated with CO 2. This support is gratefully acknowledged. Research team: dr inż. Aleksander Sobolewski dr inż. Krzysztof Dreszer mgr inż. Józef Popowicz dr inż. Lucyna Więcław Solny mgr inż. Adam Tatarczuk mgr inż. Marcin Stec mgr inż. Tomasz Szczypiński mgr inż. Piotr Kolon mgr inż. Dariusz Śpiewak mgr inż. Tomasz Spietz mgr inż. Aleksander Krótki mgr inż. Andrzej Wilk Industrial partners team: mgr inż. Stanisław Tokarski TAURON Polska Energia SA mgr inż. Sławomir Dziaduła TAURON Wytwarzanie SA inż. Stanisław Gruszka TAURON Wytwarzanie SA mgr inż. Jerzy Janikowski TAURON Polska Energia SA mgr inż. Janusz Zdeb TAURON Wytwarzanie SA Thank you for your attention Research task head: dr hab. inż. Marek Ściążko, prof. nadzw. E-mail: office@ichpw.pl Internet: www.ichpw.zabrze.pl 20/20