Solid amine sorbents for CO_(2) capture by chemical adsorption: A review

Amines are well-known for their reversible reactions with CO_(2),which make them ideal for CO_(2) capture from several gas streams,including flue gas.In this respect,selective CO_(2) absorption by aqueous alkanolamines is the most mature technology but the process is energy intensive and has also corrosion problems.Both disadvantages can be diminished to a certain extent by chemical adsorption of CO_(2) selectively.The most important element of the chemical adsorption of CO_(2) involves the design and development of a suitable adsorbent which consist of a porous support onto which an amine is attached or immobilized.Such an adsorbent is often called as solid amine sorbent.This review covers solid amine-based studies which are developed and published in recent years.First,the review examines several different types of porous support materials,namely,three mesoporous silica(MCM-41,SBA-15 and KIT-6)and two polymeric supports(PMMA and PS)for CO_(2) adsorption.Emphasis is given to the synthesis,modifications and characterizations-such as BET and PXRD data-of them.Amination of these supports to obtain a solid amine sorbent through impregnation or grafting is reviewed comparatively.Focus is given to the adsorption mechanisms,material characteristics,and synthesis methods which are discussed in detail.Significant amount of original data are also presented which makes this review unique.Finally,relevant CO_(2) adsorption(or equilibrium)capacity data,and cyclic adsorption/desorption performance and stability of important classes of solid amine sorbents are critically reviewed.These include severa PEI or TEPA impregnated adsorbents and APTES-grafted systems.

Pilot testing of CO_(2) capture from a coal-fired power plant-Part 1:Sorbent characterization

Post-combustion CO_(2)capture followed by sequestration is one of the only feasible means to significantly reduce CO_(2)emissions from existing fossil-fuel-fired power plants.This paper is Part 1 of a two-part paper highlighting key results from a project sponsored by the US Department of Energy and supported by industrial groups with the objective of demonstrating the viability of solid sorbents for CO_(2)capture.The overall objective of the effort was to validate solid sorbent-based post-combustion CO_(2)capture through slipstream pilot testing at a coal-fired power plant using a temperature-swing adsorption process.In Part 1 of this work,the results from laboratory characterization of the sorbent selected for the pilot-scale demonstration are presented.A great deal of research related to sorbent development and evaluation has occurred to date but,for the most part,these promising materials have yet to be paired with a feasible process and demonstrated at the pilot scale.The sorbent selected for pilot-scale evaluation under this project consisted of an ion-exchange resin that incorporated amines that were covalently bonded to the substrate.During the sorbent characterization portion of this work,the sorbent was characterized by a range of methods intended to provide information to support the design and operation of the pilot-scale CO_(2)-capture process,including equilibrium adsorption isotherms,adsorption and regeneration kinetics,impact of moisture and oxygen on CO_(2)working capacity,sorbent thermal properties,sorbent strength and attrition,and optimum particle-size distribution.This paper reports results from sorbent characterization testing and how these characteristics influenced the type and size of the CO_(2)-capture process equipment.In Part 2 of this work,results from tests of 1-MWe pilot-scale process equipment loaded with the sorbent described in Part 1 will be presented and analysed.

Pilot testing of CO_(2) capture from a coal-fired power plant-Part 2:Results from 1-MWe pilot tests

Using a 1-MWe slipstream pilot plant,solid-sorbent-based post-combustion CO_(2) capture was tested at a coal-fired power plant.Results from pilot testing were used to develop a preliminary full-scale commercial design.The sorbent selected for pilot-scale evaluation during this project consisted of an ion-exchange resin that incorporated amines covalently bonded to the substrate.A unique temperature-swing-absorption(TSA)process was developed that incorporated a three-stage fluidized-bed adsorber integrated with a single-stage fluidized-bed regenerator.Overall,following start-up and commissioning challenges that are often associated with first-of-a-kind pilots,the pilot plant operated as designed and expected,with a few key exceptions.The two primary exceptions were associated with:(i)handling characteristics of the sorbent,which were sufficiently different at operating temperature than at ambient temperature when design specifications were established with lab-scale testing;and(ii)CO_(2) adsorption in the transport line between the regenerator and adsorber that preloaded the sorbent with CO_(2) prior to entering the adsorber.Results from the pilot programme demonstrate that solid-sorbent-based post-combustion capture can be utilized to achieve 90%CO_(2) capture from coal-fired power plants.