Article pubs.acs.org/IECR
Nationwide, Regional, and Statewide CO2 Capture, Utilization, and Sequestration Supply Chain Network Optimization M. M. Faruque Hasan, Fani Boukouvala, Eric L. First, and Christodoulos A. Floudas* Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States S Supporting Information *
ABSTRACT: We design a CO2 Capture, Utilization, and Sequestration (CCUS) supply chain network with minimum cost to reduce stationary CO2 emissions and their adverse environmental impacts in the United States. While doing so, we consider simultaneous selection of source plants, capture technologies, capture materials, CO2 pipelines, locations of utilization and sequestration sites, and amounts of CO2 storage. The CCUS costs include the costs of flue gas dehydration, CO2 capture, compression, transportation and injection, and revenues from CO2 utilization through enhanced oil recovery (CO2-EOR). The dehydration, capture, and compression costs are derived using advanced modeling, simulation, and optimization of leading CO2 capture processes. Our results suggest that it is possible to reduce 50−80% of the current CO2 emissions from the stationary sources at a total annual cost ranging $58.1−106.6 billion. Furthermore, it is possible to generate $3.4−3.6 billion of revenue annually through supplying CO2 for CO2-EOR. Overall, the optimal CCUS supply chain network would correspond to a net cost of $35.63−43.44 per ton of CO2 captured and managed. Such a cost-effective network for CO2 management is attained due to (i) using novel materials and process configurations for CO2 capture, (ii) simultaneous selection of materials and capture technologies, (iii) CO2 capture from diverse emission sources, (iv) CO2 utilization for enhanced oil recovery, and (v) nationwide CO2 storage. Results for the regional and statewide (Texas) CCUS are also favorable.
1. INTRODUCTION More than 60% of the total anthropogenic CO2 emissions in the United States are attributed to stationary sources, which include power plants, cement production, iron and steel industries, refineries, petrochemicals, gas processing plants, and facilities that consume fossil fuels. These sources are geographically identifiable with reliable emission estimates in the United States.1 Emissions from the stationary sources can be reduced by capturing CO2 in bulk and then isolating it from the atmosphere through utilization and geological storage (aka sequestration). Such a scheme for long-term CO2 containment is widely known as CO2 capture, utilization, and sequestration (CCUS).2−5 The conceptual structure of CCUS is illustrated in Figure 1. In a CCUS chain, CO2 is first captured from the source of emission,
and eventually replace the naturally occurring CO2 with CO2 from anthropogenic sources for enhanced oil recovery (CO2EOR).20,21 CO2-EOR would potentially enable incremental oil recovery up to 15% of the original oil in place (OOIP).1 Furthermore, most CO2 storage could be done beneath leasable lands, since about 77% of the identified stationary CO2 sources are within 100 miles of federal lands.1 Often the major challenge toward large-scale deployment of CCUS stems from its high cost. The costs of CO2 capture and sequestration (without utilization) assessed for power plants range from $72 to $114/ton of CO2 avoided.22−24 CO2 avoidance from high-purity CO2 sources ($30−70), biomass conversion ($35−80), refineries ($45−120), cement ($55−150), and iron and steel ($60−80) are considered on an ad hoc basis. The major factors that would affect a nationwide CCUS cost are 1. CO2 source: source type and location 2. CO2 capture and compression: feed flow rate, feed CO2 composition, feed moisture content, capture technology, capture material, CO2 purity, CO2 recovery, energy penalty 3. CO2 transportation: distance from capture to utilization/ sequestration site, transportation mode, CO2 amount 4. CO2 utilization: CO2 demand, CO2 price 5. CO2 sequestration: sequestration type, depth and number of injection wells, storage capacity
Figure 1. A conceptual CCUS supply chain.
and then compressed and transported via pipeline to a site where it is utilized for economic benefits, or injected for sequestration. CCUS has the potential to reduce energy-related CO2 emissions by 20%.6 CCUS is, in fact, a logical pathway toward cleaner energy while reducing the carbon footprint of conventional, nonconventional, and hybrid energy7−14 sources including coal, oil, natural gas, stranded natural gas, coalbed methane, landfill gas, biomass, municipal solid waste (MSW), shale gas, and tar sands.15,4,16−18 As of mid-2012, at least 254 CCUS projects are in operation or under planning and development stages worldwide.19 In the United States, opportunities exist to supplement © 2014 American Chemical Society
Special Issue: John Congalidis Memorial Received: Revised: Accepted: Published: 7489
September 5, 2013 February 17, 2014 February 18, 2014 February 18, 2014 dx.doi.org/10.1021/ie402931c | Ind. Eng. Chem. Res. 2014, 53, 7489−7506
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CO2 capture25,26 is the heart of a CCUS chain and incurs the majority of the total CCUS cost. A major challenge is the selection of CO2 capture technologies and materials for diverse sources. Although many separation-based technologies exist for CO2 capture, not all are economically attractive. Absorption is the most mature technology for CO2 capture.27−32 It is the most studied separation scheme considered for CCUS.33−36 However, high energy cost for regeneration, solvent degradation and loss, corrosion, etc. often make the absorption process prohibitive for use in CO2 capture. Adsorption-based CO2 capture is another attractive way of CO2 capture from dry flue gases.37−46 Major adsorbents for CO2 separation include microporous/mesoporous silica or zeolites, activated carbonaceous materials, and metal organic frameworks (MOFs).47−51,45 Membranes are not yet commercially popular for postcombustion CO2 capture, mainly because of the high capital costs52,53 associated with feed gas compression to increase the driving force for separating CO2 with low partial pressure. However, recent works on multistage separation and vacuum permeate pumping have shown promise toward cost-effective CO2 capture using membranes.28,54,52,55,56 Different polymeric, facilitated transport, inorganic, and mixed matrix membranes show potential for CO2 capture.57−60 For large-scale CCUS implementation, it is critical to optimally integrate capture, compression, transportation, utilization, and sequestration activities for the design of large-scale CCUS networks. Several studies addressed regional CO2 capture and sequestration.61−65 Bakken et al.66 presented a linear model for the optimal design of CO2 capture and storage. Middleton and co-workers67−69 developed a framework for spatially optimizing CO2 capture and sequestration infrastructure by generating candidate networks and then selecting the optimal topology based on mixed-integer optimization. Kuby et al.70 proposed a mixed-integer linear optimization (MILP) model to determine the quantity of CO2 capture and sequestration in the presence of carbon tax. Lee and co-workers71,72 proposed mathematical models for CO2 capture, transportation, and storage networks to select the storage sites and volumes of CO2 to be stored. Tan et al.73 proposed a continuous-time mixed integer and nonlinear optimization (MINLP) model for matching industrial CO2 sources and reservoirs. van den Broek et al.74 assessed the economic feasibility of capture and sequestration for the electricity generation sector and analyzed strategies to attain different CO2 reduction levels in the context of the Netherlands. Zheng et al.75 performed a study on the CO2 capture and sequestration opportunities in China. Johnson and Ogden76 presented an optimization model for the southern United States using real geographic information. The Department of Energy (DOE) launched a Carbon Sequestration Program to focus on developing technologies to store CO2 from energy producers and other industries without hindering the energy supply in the United States.77,1,19 Optimization of the CO2 transportation network also gained significant attention in recent times.78−80 While studies exist on the CO2 management using CO2 capture and sequestration infrastructure in isolation and without exploiting utilization opportunities,81,82,76,75,83−87,65,66,69,88 it remains an open question whether a nationwide CCUS deployment would be economically feasible or not. To our knowledge, no work exists on designing an optimal nationwide CCUS network that considers costs of capture, compression, transportation, utilization and sequestration and simultaneously selects CO2 sources, capture materials, capture technologies, and utilization and sequestration sites. Technologies for CCUS schemes are historically developed independently of one another.
Such standalone development makes the integration a complex and challenging task. Furthermore, diverse emission scenarios preclude a simplistic study toward the design of a cost-effective CCUS. Not all stationary sources have the same CO 2 compositions in their CO2 containing streams or flue gases. Coal and natural gas-fired power plants, which are the major sources of CO2 with large flow rates, have only 3−15% CO2 in the flue gases. On the other hand, iron and steel production, agricultural processing, and sugar production often produce streams containing more than 40% CO2. CCUS cost varies with flue gas composition and flow rate,28,37 and capturing CO2 from the right sources and storing in the right sites in the right amounts are crucial for a CCUS chain to be costeffective. The selection of technologies and that of materials for CO2 capture are equally important. Hasan et al.28,37 calculated the costs of optimized capture and compression for four leading capture technologies, namely absorption, membrane, pressure swing adsorption (PSA), and vacuum swing adsorption (VSA) for a wide range of stationary sources, and showed that no single technology is the best or even feasible for all CO2 compositions and flow rates. More recently, it has been shown for PSA that even when the technology remains the same, cost could significantly vary depending on the materials selected for CO2 capture.45 In this work, we report the design and optimization of a comprehensive CCUS supply chain network that includes the selection of different types of stationary sources, alternate capture technologies and materials, CO2 utilization, and sequestration in different types of geological storage. Furthermore, our cost model includes the capture, compression, transportation, and injection costs and revenues from CO2 utilization. The capture and compression costs are derived using advanced modeling, simulation, and optimization of CO2 capture processes, while the transportation and injection costs are computed using models from the literature. Our explicit input−output models for the capture and compression costs consider the variation in source flue gas compositions and flow rates. We consider real geographic locations and storage estimates from the available database and incorporate rigorous cost estimations based on material selection and process optimization. We present a CO2 supply chain model that is applicable for the synthesis of CCUS networks for nationwide, regional, and statewide CO2 management. We also determine the overall costs of CCUS supply chain networks for different levels of CO2 reductions. The novel features of this work include (1) defining a large-scale CCUS scheme as a CO2 supply chain network that actively considers CO2 capture, utilization, and sequestration; (2) simultaneous selection of capture technologies and materials for different CO2 source types; (3) designing CCUS networks based on real geographic locations and reliable estimates of CO2 emissions from various stationary sources and real geographic locations and reliable estimates of CO2 utilization and storage resources in the entire United States; and (4) using explicit models for flue gas dehydration, CO2 capture and compression, and transportation and injection costs, which are derived using rigorous modeling, simulation, and optimization. The article is organized as follows. We provide a description of CCUS and its major components, and state the CCUS supply chain network problem in section 2. In section 3, we discuss the CCUS economics and present the calculations for various costs and revenues. We present the detailed mathematical model in section 4. The computational results for the nationwide, statewide and regional CCUS networks are presented in section 5 and are further discussed in section 6. 7490
dx.doi.org/10.1021/ie402931c | Ind. Eng. Chem. Res. 2014, 53, 7489−7506
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Figure 2. Stationary sources of CO2 in the United States. (a) U.S. map locating the stationary sources, where each circle represents a source. 3317 sources are screened for CCUS which are shown based on their locations and relative CO2 emissions. Different colors are used to show the 20 source types. (b) Number of sources belonging to 20 source types are shown using a pie chart. (c) The histograms showing the distribution of sources based on the amount of CO2 emitted annually.
Figure 3. Saline formations in the United States for CO2 sequestration. The map shows the locations of basins (solid green) and potential CO2 injection locations (marked with stars) for sequestration in saline formations. These injection locations are selected on the basis of the unique latitude and longitude coordinates provided in the NATCARB database. The estimated CO2 injection amounts are aggregated for the sites with the same coordinates.
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Figure 4. Unmineable coal areas in the United States for CO2 sequestration. The map shows unmineable coal areas and 1837 potential CO2 injection sites. Many of these sites have the same geographic locations.
Figure 5. Oil and gas reservoirs in the United States for CO2 sequestration. U.S. oil and gas reservoirs are shown in solid blue, while the 166 screened oil and gas reservoirs where CO2 can be utilized for CO2-EOR are marked with stars.
2. CO2 CAPTURE, UTILIZATION, AND SEQUESTRATION (CCUS) We start with the description of the major components of a CCUS network. We have collected real data for (i) CO2 sources, (ii) utilization sites, and (iii) sequestration sites in the United States. These data will be used to develop nationwide, statewide and regional CCUS supply chain networks. 2.1. CO2 Sources, Utilization Sites, and Sequestration Sites. We have located the major stationary sources and utilization and sequestration sites in the United States (Figures 2−5). All source, utilization, and sequestration estimates are collected from the National Carbon Sequestration Database and Geographic Information System (NATCARB) and Carbon Sequestration Atlas of the United States and Canada (Atlas III),1 as released by the DOE’s NETL in November 2010. Analyzing NATCARB data, we screened onshore reservoirs for CO2-EOR primarily based on the reservoir depth (2000−9800 ft), oil gravity (27−30° API), reservoir pressure (1200−1500 psia), reservoir temperature (
