• Energy Research

Abstract Bioenergy with Carbon Capture and Storage (BECCS) is a carbon removal technology that offers permanent net removal of carbon dioxide (CO2) from the atmosphere. One of the significant bioenergy resources is organic waste collected from municipal solid waste (MSW). The goal of this study was to provide an estimate of the global potential for using municipal solid waste as a resource for bioenergy with carbon capture and storage (BECCS) and to compare the feasibility of two specific BECCS options: municipal solid waste incineration with carbon capture and storage (MSW-CCS), and landfill gas combusted in a gas turbine with carbon capture and storage (LFG-CCS). To assess the feasibility of MSW-based BECCS options, techno-economic and environmental impact assessments were conducted. In the case of a “business-as-usual” scenario with no emission policy in effect, the levelised cost of electricity production from both BECCS options is higher than a coal power plant with CCS. However, these BECCS systems offer a lower cost of avoided CO2. Introducing renewable energy certificates or negative emission refund schemes to BECCS has a significant impact on the economic viability of these technologies in coal-dominant power markets. Environmental impact assessment shows that around 0.7 kg CO2-eq is removed for each kg of wet MSW incinerated, for the MSW-CCS scenario. This translates to approximately negative 2.8 billion tonnes CO2 if all the available 4 billion tonnes MSW generated per year by 2100 is utilised in a MSW-CCS system. The net GHG emission of the LFG-CCS system with an average LFG collection rate of 75% was 0.56 kg CO2-eq. Challenges include the dispersed nature of MSW resources and the lack of economic support schemes, such as commonly apply to solar and wind. Nonetheless, MSW-based BECCS technologies have significant potential for abating and in some cases removing considerable amounts of the greenhouse gases from the atmosphere, thereby contributing significantly to the COP21 emission reduction targets.

AbstractCommissioned in 2009, the CO2CRC/H3 Capture Project is demonstrating post-combustion carbon capture (PCC) on a lignite fired power plant in the Latrobe Valley, Victoria, Australia. The facility is located within International Power’s Hazelwood Power Plant and uses three different CO2 capture technologies — solvent, adsorption and membrane processes. This project, addressing the PCC issues specific for Victorian brown coal fired power stations, was initiated in July 2007 as a three year research project by the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) under the Victorian State Government’s Energy Technology Innovation Strategy (ETIS) program. The project is part of the Latrobe Valley Post Combustion Capture (LVPCC) Project — a multi site, multi scale, multi technology PCC trial. The integrated research and development program includes an evaluation of these technologies for commercial scale application. This paper describes the technologies used, how they have progressed from laboratory to pilot demonstration, the main outcomes, and plans for future developments.

AbstractCO2 capture from major stationary emission sites has been studied widely with the increasing realization of the negative impact of greenhouse gas emissions on climate change. In terms of capture technology, solvent scrubbing, membrane processes and adsorption processes are the major contenders with the latter making significant progress over the last decade due to both improved adsorbent and process design and operation. As is well known, capturing CO2 from flue gases at coal-fired power stations by pressure/vacuum swing adsorption is complicated by the existence of significant amounts of water, SOx, NOx and other impurities, which are detrimental to most commercial CO2 selective-adsorbents. Conventional adsorption-based CO2 capture processes rely on using a pre-treatment stage to remove water, SOx and NOx, which adds considerably to the overall cost. In contrast, we report here an adsorption process developed in our laboratory which directly tackles the untreated flue gas without a separate pre-treatment stage by using a propriety multiple-layered bed comprising different adsorbents. The species CO2, H2O, SOx and NOx are processed in the same column within different function layers optimized according to adsorption properties and process conditions. A fully programmable logic controller (PLC) automated three-column pilot plant was built to perform the study with real-time control and data acquisition conducted through Human Machine Interface/Supervisory Control and Data Acquisition (HMI/SCADA) system. Through running continuous experiments, the effects of impurities on process performance such as CO2 purity, recovery and process power are investigated and reported. This is the first in-depth report of the performance of adsorption based capture plants in the presence of impurities found in real flue gas streams.

Abstract A large number of promising adsorbent materials for CO2 capture are reported almost daily. Unfortunately, the assessment of an adsorbent in a process is far more challenging. Statements on expected performance are usually confined to visual inspection of isotherms or calculations of pure component selectivities. These are poor indicators of performance in an actual capture process. We present here a new simplified pressure/vacuum swing adsorption model which can be used to quickly screen adsorbents for use in CO2 capture applications. The model strikes a balance between full adsorption simulation (which requires detailed knowledge of PSA operation and is time consuming) and simple visual inspection of isotherms and calculations of selectivities (which is incorrect and misleading in many cases). Our model has been validated against analytical PSA models, full adsorption numerical simulations, and experiments. Using post-combustion VSA as an example, we use the model to compare several types of adsorbents (zeolite 13X, Mg-MOF-74, Activated Carbon, PEI/MCF chemisorbent). Our analysis shows that 13X remains the best adsorbent in VSA applications (for dry flue gas of 12% composition) even though Mg-MOF-74 shows considerably higher CO2 capacity. We have also conducted a sensitivity study to determine which properties are most important to improving performance and we estimate the limits of PSA performance. Adsorbent selectivity and thermal effects have a more significant effect on the specific power consumption than does CO2 adsorption capacity. The optimal heat of adsorption of CO2 for PSA application is between 35 and 45 kJ/mol regardless of N2 heat of adsorption. Furthermore, continual increase in surface area is not necessarily beneficial to overall performance, becoming more detrimental as the heat of adsorption of N2 increases. As an estimate of an upper limit of material performance, a hypothetical material with the same surface area as MOF-177, no N2 adsorption, and a CO2 heat of adsorption of 35 kJ yields a 68% increase in working capacity and an increase in purity from 78% to 94% when compared to 13X.

Abstract Australia has committed to meeting its international obligations to decrease its greenhouse gas emissions including transitioning toward decarbonising its emission-intense energy sector. However, it is facing the dual problems of increasing electricity cost and decreasing energy security. One of the potential contributions to reducing its emission while supplying reliable power is deployment of bioenergy with carbon capture and storage (BECCS). BECCS is a carbon removal technology that offers permanent net removal of carbon dioxide from the atmosphere together with the prospect of negative emissions. The present study was undertaken to assess the potential contribution of BECCS to achieving long term decarbonising of the Australian energy sector. This study considers the availability of sustainable bioenergy resources and the economic viability and environmental impacts of BECCS. In order to avoid the ecological uncertainties and social challenges of dedicated energy crops, this study focuses on organic waste from the municipal, agricultural, and forestry sectors. Based on the quantity of biomass resources available, BECCS options in Australia have the potential to remove a total of 25 million tonne CO2/year from the atmosphere as negative emissions by 2050. In addition, BECCS systems could supply Australia with up to 13.7 terawatt-hours of renewable power by mid-century which is around 3.6% of expected gross electricity generation in 2050. Deployment of BECCS as a reliable supplier of electricity would potentially enhance the flexibility and diversity of Australia’s energy portfolio and remove carbon dioxide from the atmosphere. However, deployment of BECCS as a carbon negative strategy will require strong policy support.

AbstractThe potential benefits of precombustion carbon dioxide capture are well documented, and adsorption remains a promising separation process in this area. This paper details work to identify and assess the potential of high temperature adsorbents suitable for precombustion capture.The aim of this paper is to schematically identify adsorbents that are suitable for carbon capture in different temperature ranges. A critical aspect of this work is to assess the materials not only in terms of carbon dioxide isotherms and absolute loading, but to consider the wide range of other properties that are required to achieve an industrially feasible adsorbent - selectivity, cycling capacity, stability, kinetics, high pressure loading, fate of other components (including water, H2S, NH3, CO and N2). It is only when all these requirements are sufficiently met, that an adsorbent can be consider worthy of industrial consideration. A range of analytic screening tests are described to enable a full characterisation of the merit of a specific adsorbent.The adsorbents investigated are zeolites (NaX, calcium chabazite), commercially available hydrotalcite, layered double hydroxides/oxides (LDH/Os), and magnesium double salts. Each operates in a different temperature range and offers potential for integration within an Integrated Gasification and Combined Cycle precombustion process train.Some of the promising and significant conclusions of this work are - •Magnesium double salts present very favourable carbon dioxide isotherms and demonstrate significant carbon dioxide loading and the isotherms are suitable for PSA or TSA operation at high temperature.•LDHs or their derivatives as layered double oxides can adsorb up to 1.5mol/kg CO2. Water does not affect CO2 sorption, and the material has good recyclability in TSA.•The selectivity of hydrotalcite is well documented. However there is no reported literature on the adsorptive behaviour of these materials with respect to trace components - H2S and NH3. These results are reported.•Calcium chabazite displays useful CO2 loading potential in a unique temperature range around 200 ∘C.•NaX has the potential to replace Selexol at an operating temperate of 130 ∘C.

here f = 0.7 (feed/vacuum blower efficiency), k=1.28 (CO2) or 1.4 (air), Qin = instantaneous volume flow rate (m3/s) entering the feed or ecycle compressor or vacuum pump, Patm = atmospheric pressure (101.375kPa), Pout = instantaneous discharge pressure (kPa) from the ecycle or feed compressor and Pin = instantaneous inlet pressure (kPa) to the feed compressor or vacuum pump. The publisher/author(s) would like to apologise for any inconvenience this may have caused to the authors of this article and readers f the journal.

Abstract Bioenergy with carbon capture and storage (BECCS) involves the conversion of biomass to energy, producing CO2 which is sequestered, transported and then permanently stored in a suitable geological formation. Thus, a negative flow of CO2 from the atmosphere to the subsurface is established. The potential of BECCS to remove CO2 from the atmosphere (in addition to generating energy) makes it an attractive approach to help achieving the ambitious global warming targets of COP 21. BECCS has a range of variables such as the type of biomass resource, the conversion technology, the CO2capture process used and storage options. Each of the pathways to connect these options has its own environmental, economic and social impacts. This study attempts to integrate these impacts into a three pillar sustainability framework (3PSF) approach. As an example, the 3PSF approach is applied to bioenergy from organic waste collected from municipal solid waste (MSW). Global and Australian potentials for using municipal solid waste as resource for bioenergy and coupling it with carbon capture and storage (BECCS), was investigated. Two BECCS systems, municipal solid waste incineration with carbon capture and storage (MSW-CCS) and landfill gas combusted in gas turbine with carbon capture and storage (LFG-CCS) were modelled. In the case of business-as-usual scenarios with no emission policy in place, the cost of electricity from both BECCS options is higher than for unmitigated coal power generation. However, introducing renewable energy certificate or negative emission refunding schemes has a significant impact on the economic viability of these technologies. Environmental impact assessments show that in the MSW-CCS model, for each kg of wet MSW incinerated around 0.7 kg CO2,eq is removed from the atmosphere. BECCS has the potential to be a valuable step towards a low-carbon energy system. However, if planned unsustainably it could compromise the natural ecosystem and social equity. The importance of the presented study is in its holistic approach to assessing the sustainability of different BECCS routes and providing a comprehensive adaptive management system that enables decision-makers to plan BECCS options in a transparent and timely manner.