Solvent-based Post-combustion Carbon Capture Research Articles

Dynamic modeling and comprehensive analysis of an ultra-supercritical coal-fired power plant integrated with post-combustion carbon capture system and molten salt heat storage

Reducing carbon footprints and enhancing operational flexibility are crucial for the future development of coal-fired power plants (CFPPs). This necessitates the deployment of post-combustion carbon capture (PCC) and molten-salt heat storage (MSHS) systems. Given the various integration schemes and complex interactions, understanding the comprehensive performance of the integrated CFPP-PCC-MSHS system is important. This paper proposes an integration scheme for 1000MWe ultra-supercritical CFPP, solvent-based PCC and MSHS, achieving cascade energy utilization. A dynamic simulation model for the CFPP-PCC-MSHS system is developed to understand the dynamic couplings between subsystems. Comprehensive performance analyses are conducted to evaluate the thermodynamics, flexibility and safety of the integrated system under various operating conditions. Simulation results indicate that deploying MSHS reduces the thermal and exergy efficiencies of the CFPP-PCC system by 0.18 % and 0.19 %, respectively, but effectively expands the adjustable power load range by 6.08 % under the fixed 90 % CO2 capture rate mode. Meanwhile, the integration of MSHS offers alternative pathways to improve the power ramping rate to 13.33 MW/min. The heat charging/discharging process of MSHS induces fluctuations in temperature and pressure within the turbine, potentially affecting plant operating safety. This paper provides useful insights for the design, retrofit and operation of new generation of CFPPs.

Operating optimization of biomass direct-fired power plant integrated with carbon capture system considering the life cycle economic and CO2 reduction performance

Biomass direct-fired power plant integrated with carbon capture system can achieve negative CO2 emission during the power generation, which provides an important technology pathway for the transformation of energy system towards carbon neutrality. Understanding the economic competitiveness and CO2 reduction potential of the plant, and identifying the optimal operating mode are the key to fully exert the advantages of the technology. For this reason, this paper develops life cycle economic and CO2 emission assessment models for the biomass direct-fired circulating fluidized bed boiler power plant (BCFBP) integrated with solvent-based post-combustion carbon capture (PCC) system. The levelized cost and CO2 emission of energy indexes are then applied to evaluate the performance of the BCFBP-PCC system. Based on the life cycle assessment, a novel economy and CO2 reduction dual-objective operating optimization approach is proposed for the BCFBP-PCC to find the optimal hourly power generation and CO2 capture level of the plant under given market conditions. The static investment payback period is employed as a constraint in the optimization to narrow down the range of the solution set and provide clearer guidance for system operation. This paper provides the first work pioneered the economic and negative carbon operation optimization of the BCFBP-PCC system.

Modelling, scale-up and techno-economic assessment of rotating packed bed absorber for CO2 capture from a 250 MWe combined cycle gas turbine power plant

The huge sizes and costs of the packed bed (PB) absorbers and strippers in solvent-based post-combustion carbon capture are part of the challenges limiting its commercialization. The rotating packed bed (RPB) absorbers and strippers have the potential to reduce the size and cost of the CO2 capture process when used to replace their PB counterparts. However, the size and cost have not been quantified for a large-scale RPB. Therefore, this paper is devoted to providing detailed technical and economic assessments of a large-scale RPB absorber operated with concentrated (55-75 wt%) monoethanoamine (MEA). To achieve this, a steady-state rate-based model of the RPB absorber was developed and validated in Aspen Custom Modeller®. The model was scaled up to capture CO2 from the flue gas of a 250 MWe CCGT power plant using an iterative scale-up methodology proposed in this study. Technical assessments of the large-scale RPB absorber indicated that a 4–11 times volume reduction factor was achieved with 55 wt% MEA concentration compared to PB absorbers. The highest volume reduction factors of 5–13 times were achieved in RPB absorber operated with 75 wt% MEA. Economic assessments show that the capital expenditures of the RPB absorbers were lower by 3–53%. The CO2 capture cost was also lower ($6.5/tCO2–$9/tCO2) compared to $15/tCO2–$24/tCO2 obtained for the PB absorbers.

Robust control and flexible operation for commercial-scale coal-fired power plant with solvent-based post-combustion carbon capture

Coal-fired power plant integrated with post-combustion carbon capture (CFPP-PCC) process exhibits strong nonlinearity and multi-variable connections. These dynamics along with unknown disturbances make it a challenging task to realize robust control and flexible operation in CFPP-PCC system. For this reason, this paper develops an extended state observer based stable model predictive control (ESOSMPC) in order to reject unknown disturbances and to achieve flexible operation with closed-loop stability. In the proposed control structure, an extended state observer is utilized to give accurate estimation for plant behavior change and unknown disturbances. This information will be used in active disturbance rejection, which aims to alleviate negative effects of disturbances and to enhance control performance. Stable model predictive control with infinite input-output based objective function is developed in order to fulfill Lyapunov stability condition, guaranteeing a stable operation for the integrated process. The proposed controller is compared with conventional MPC/PID controller under varying working conditions. Simulation results show that the presented ESOSMPC is able to achieve robust control in a multi-disturbance situation and to attain flexible operation in a broad-range load variation scenario.

Dynamic modeling and coupling characteristics analysis of biomass power plant integrated with carbon capture process

Biomass direct-fired circulating fluidized bed boiler has distinguished advantages of strong fuel adaptability, high combustion efficiency and low NOX emission, thus has been regarded as one of the important pathways for biomass utilization. Retrofitting the biomass direct-fired circulating fluidized bed boiler power plant (BCFBP) with carbon capture can strongly support the goal of carbon neutrality, because negative CO2 emission is achieved during the power generation. Nevertheless, the biomass direct-fired circulating fluidized bed boiler is sensitive to the combustion condition, high in operating costs, slow in dynamic response and poor in regulating capability. The integration of carbon capture may pose significant changes on the operating safety, efficiency and flexibility. A comprehensive analysis is thus required to understand the interactions between the BCFBP and carbon capture under various operating conditions. To this end, this paper develops a plant-wide dynamic model for a 130 ton/h BCFBP integrated with solvent-based post-combustion carbon capture (PCC) system. Multi-stage models of biomass combustion, steam generation and steam turbine-feedwater heater systems are developed to represent the dynamic interactions among biomass, heat, electricity and carbon, so that the impacts of BCFBP operation on the PCC process can be evaluated. Detailed BCFBP-PCC connecting system model are also developed to reflect the dynamic changes of steam/water flowrate, pressure and temperature in the steam turbine system caused by the integration of PCC. The developed model is then used to analyze the system interactions, operating costs, negative carbon capability and load ramping flexibility of the integrated BCFBP-PCC. Results show that the integration of PCC 1) causes significant impacts on the water/steam parameters of the steam turbine-feedwater heaters behind the reboiler steam extraction point; 2) reduces the power output of BCFBP by 26.12 % under 95 % CO2 capture level condition; 3) expands the power output variation range of the BCFBP from 22.3 to 36.6 MWe and provides the negative CO2 emission capacity from 2.2 to 6.9 kg CO2/s; 4) offers a feasible way to improve the power ramping performance through flexible distribution of the water/steam in the steam turbine-feedwater heater system. This paper provides specific guidance for the design, retrofit and operation of the BCFBP-PCC plant.

Experimental investigation of microwave-assisted regeneration of carbon-rich aqueous solutions

Solvent-based post combustion carbon capture is the most prevalent carbon capture technology where 30wt% Monoethanolamine (MEA) is the benchmark solvent used for carbon capture with high energy consumption. Microwave (MW)-assisted carbon-rich solvent regeneration is one of the emerging technologies for CO2 stripping with lesser energy consumption and experimental study covers in these aspects. The factors and levels considered for designing L27 orthogonal array includes nominal power input (10%, 20% and 30% of 800 Watts), regeneration time (5, 15 and 25 min), solvent load (40, 60 and 80 g) and different solvents (30wt% MEA, 20wt% potassium carbonate, and 20wt% piperazine). Physicochemical properties like carbon loading, density, viscosity, surface tension, pH and temperature were tested before and after regeneration. From the experimental investigation, it has been observed that all the physiochemical properties show decreasing trend after the regeneration except pH and temperature. An optimum conditions of lower power level, longer regeneration time and lower solvent loading exhibits better solvent regeneration in the tested conditions. In addition, 20wt% piperazine has the highest regeneration efficiency of 48%. In a cyclic process, the baseline aqueous 30wt% MEA exhibits the lowest regeneration energy of 0.13 kW/mol.CO2 with 24.26% regeneration efficiency for 10% nominal power input.

Low-carbon Operation of Combined Heat and Power Integrated Plants Based on Solar-assisted Carbon Capture

Accelerating the development of renewable energy and reducing CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emissions have become a general consensus and concerted action of all countries in the world. The electric power industry, especially thermal power industry, is the main source for fossil energy consumption and CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emissions. Since solvent-based post-combustion carbon capture technology would bring massive extra energy consumption, the application of solar-assisted carbon capture technology has attracted extensive attention. Due to the important role of coal-fired combined heat and power plants for serving residential and industrial heating districts, in this paper, the low-carbon operation benefits of combined heat and power integrated plants based on solar-assisted carbon capture (CHPIP-SACC) are fully evaluated in heat and power integrated energy system with a high proportion of wind power. Based on the selected integration scheme, a linear operation model of CHPIP-SACC is developed considering energy flow characteristics and thermal coupling interaction of its internal modules. From the perspective of system-level operation optimization, the day-ahead economic dispatch problem based on a mix-integer linear programming model is presented to evaluate the low-carbon benefits of CHPIP-SACC during annual operation simulation. The numerical simulations on a modified IEEE 39-bus system demonstrate the effectiveness of CHPIP-SACC for reducing CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emissions as well as increasing the downward flexibility. The impact of different solar field areas and unit prices of coal on the low-carbon operation benefits of CHPIP-SACC is studied in the section of sensitivity analysis.

A CFD study of a direct solar-driven desorption process for carbon capture under transient conditions

Solvent-based post-combustion carbon capture (PCC) is the most accessible technology to reduce the greenhouse gas (GHG) emissions from coal-fired power plants, however with a substantial energy penalty. This study investigates a novel concept of solar-powered solvent-based PCC, replacing the traditional stripper unit with a solar collector field (SCF) pipe network. This SCF pipe network consists of modular units termed “solar-strippers” (So-St)s that function to desorb the CO2 gas directly within the solar collector tubes. The internal design complexities of the So-St unit are poorly understood and yet to be optimised. Computational fluid dynamics (CFD) is ideal for modelling complex thermo-physical phenomena that appear in the So-St, including boiling flow, heat transfer, reaction kinetics and thermodynamics. This study develops a rigorous CFD model for a single So-St segment; the first of its kind. The model is used to assess possible design improvements using methods of enhanced heat transfer (EHT), in particular the insertion of porous and solid baffles which increase thermal efficiency and boost vapour formation. The porous and solid baffles are estimated to reduce the So-St field size by 56% and 65%, however demanding 2.5 and 6 times more pumping power, respectively. These incremental design enhancements display the utility of CFD in enabling the So-St concept to become a sustainable low-emissions carbon capture & storage (CCS) technology for cleaner energy production.

Technical and economic performance assessment of post-combustion carbon capture using piperazine for large scale natural gas combined cycle power plants through process simulation

The main challenges to the commercial deployment of the solvent-based post-combustion carbon capture technology include high energy consumption and high capital and operating costs. New solvents and alternative process configurations are being pursued to reduce the energy consumption and costs of the process. This paper investigates the technical and economic performance of the process using piperazine (PZ) solvent for a 250 MWe natural gas combined cycle power plant. Three different configurations of the process using PZ were evaluated and compared to the standard process using 30 wt% monoethanolamine (MEA) solvent. The technical performance of the process was evaluated using the rate-based model developed in Aspen Plus® V8.4 and the economic evaluation was carried out in Aspen Process Economic Analyzer®V8.4. The technical results showed that the total energy demand of the process reduces from 5.34 GJ/tCO2 using 30 wt% MEA to 3.56 GJ/tCO2 using 30 wt% PZ. The lowest energy demand of 2.76 GJ/tCO2 was achieved with the advanced flash stripper using 40 wt% PZ. The economic results show that the lowest total annual cost of M$26.58 per year and CO2 capture cost of $34.65 per tonneCO2 were obtained using the advanced flash stripper (AFS) with 40 wt% PZ. It was concluded that the 40 wt% PZ solvent would bring practical technical and economic benefits to the large-scale applications of the capture process compared to the current 30 wt% MEA solution. Therefore, this study will inspire policymakers and researchers towards the large-scale deployment of solvent-based PCC process.

Simultaneous parametric optimization for design and operation of solvent-based post-combustion carbon capture using particle swarm optimization

High investment and operating costs are two barriers hindering the commercial deployment of solvent-based post combustion CO2 capture (PCC) technology in power industry. Since upstream power plants are always in flexible operation, conventional approaches which carry out the design based on a fixed condition fail to achieve the best overall performance. To this end, this paper proposes a simultaneous size and operation parameters optimization strategy for the PCC process, in which the flexible operation of the CFPP is taken into account during the design stage. The technique of particle swarm optimization (PSO) is used in a hierarchical manner to find the design and operating conditions of the PCC with minimal total annualized cost. To further explore the optimization potential, the average CO2 capture level in one day is taken as the environmental constraint rather than the conventional instantaneous one. The proposed approach is tested on the PCC design for an existing 660 MW supercritical coal-fired power plant. The optimization results of four different design approaches are compared with the economic, efficiency and environmental (3E) performance being fully assessed. The simulation results show that by using the proposed optimization method, 14.45% reduction in TAC can be attained compared with the conventional approach.

Generic techno-economic optimization methodology for concurrent design and operation of solvent-based PCC processes

A techno-economic equation-based methodology is developed for optimal design and operation of integrated solvent-based post-combustion carbon capture (PCC) processes using a rate-based model for the interaction of gas and liquid. The algorithm considers a wide range of techno-economic design and operation parameters such as number of absorber/desorber columns, height of columns, diameter of columns, operating conditions (P, T) of columns, pressure drop, packing type, percentage of CO2 mitigated, captured CO2 purity, amount of solvent regeneration, flooding velocities of columns, and number of compression stages. A case study is conducted to showcase two common objective-functions i) minimizing total capital investment, and ii) minimizing levelized capture costs, both for a 300 MW coal-power plant in Australia. The former objective leads to the lowest possible total capital cost of $312.4 M corresponding to levelized carbon capture cost of 58.1 $/tonne−CO2. For objective (ii), however, the lowest levelized carbon capture cost is found to be around ten percent lower (52.8 $/tonne−CO2), though it leads to a higher total capital cost ($325.2 M). The results indicate that the design and operation variables are markedly interactive, and no unique optimal design exists which can deliver all desired outcomes at once. Therefore, decisions on the selection of right variables become dependent on the decision-makers techno-economic objectives.

Tailored solar field and solvent storage for direct solvent regeneration: A novel approach to solarise carbon capture technology

For effective greenhouse gas (GHG) emission reduction, solvent-based post-combustion carbon capture (PCC) is the most recognized remedy option worldwide. Due to the very high thermal energy demand of this technology and the potential impact on the power production, solar-assisted PCC (SPCC) was proposed to offset part of this energy penalty. However this option is far from commercialization readiness, because of the solar intermittence and the costly thermal energy storage (TES).This paper promotes a dynamic carbon capture using innovative solar collector field (SCF). By eliminating the complex and costly stripper/s from the conventional PCC, we propose regenerating the solvent directly in the SCF and proportionally to the solar thermal energy gain. We also propose an underground solvent storage system instead of TES to buffer in-between the dynamic solvent regeneration via SCF and the steady-state absorption process in the absorber/s. For capturing 1.5 million tonneCO2/y from a 660 MWe coal-fired power plant in three representative locations in Australia, it is found that the equivalent annual cost of desorption is quite reasonable, particularly at higher solar multiples (SM). For SM = 1.5, the levelized cost of desorption is the lowest in Townsville ($ 12.34 per tonneCO2), followed by Sydney ($16.31 per tonneCO2), while Melbourne would need larger SCF (SM = 2.0) to lower the levelized cost of desorption ($ 22.52 per tonneCO2). These costs are calculated irrespective of the credits gained from steam preservation for power production and the resulted positive impact on the overall life cycle analysis. Noting the trajectory trend of GHG reduction cost, this novel approach in solarising carbon capture may bring SPCC to the competitive advantage in short/mid-term.

A new method for scale-up of solvent-based post-combustion carbon capture process with packed columns

Solvent-based post-combustion carbon capture (PCC) with packed column is the most commercially ready CO2 capture technology. To study commercial-scale PCC processes, validated pilot scale models are often scaled up to commercial-scale using the generalized pressure drop correlation (GPDC) chart which requires assuming the column pressure drop. The GPDC method may lead to either over-estimation or under-estimation of the column diameter. In this paper, a new method for estimating the packed column diameter without assuming the pressure drop has been proposed and used for model scale-up. The method was validated by scaling between two existing pilot plant sizes. The CO2 capture process was simulated in Aspen Plus® and validated at pilot scale. The validated model was scaled up to commercial CO2 capture plant capable of serving a 250 MWe combined cycle gas turbine power plant using the new method proposed in this study. The results obtained from the scale-up study were compared to those obtained when the GPDC method was used to design the same commercial CO2 capture plant. The results showed that the GPDC method overestimated the absorber and stripper diameter by 1.6 % and 8.5 % respectively. Process simulation results for the commercial-scale plant showed about 2.12 % and 5.63 % lower solvent flow rate and reboiler duty with the proposed method. Therefore, the capital and operating costs for the process using the newly proposed scale-up method could be lower based on our estimates of the column dimensions, solvent flow rate and specific reboiler duty.

Control of Solvent-Based Post-Combustion Carbon Capture Process with Optimal Operation Conditions

Solvent-based post-combustion carbon capture (PCC) is a mature and essential technology to solve the global warming problem. The high energy consuming issue and the flexible operation required by the power plants inquire about the development of effective control systems for PCC plants. This study proposes the optimal-based control approach that utilizes optimal set-point values for the quality controllers. The five optimal-based control schemes studied all employed L/G (liquid to gas ratio in absorber) as one quality control variable. Performance comparisons with a typical conventional control scheme are conducted employing a rate-based dynamic model for the MEA (monoethanolamine) solvent PCC process developed on a commercial process simulator. Compared to the typical control scheme, the optimal-based control schemes provide faster responses to the disturbance changes from the flue gas conditions and the set-point change of the CO2 capture efficiency, as well as better results in terms of IAEs (integral of absolute errors) of capture efficiency and reboiler heat duty during the stabilization period. LG-Tstr and LG-Tabs-Cascade are the best schemes. In addition to L/G, these two schemes employ the control of Tstr (the temperature of a stage of stripper) and a cascade control of Tabs (the temperature of a stage of absorber) (outer loop) and Tstr (inner loop), respectively.

CO2/SO2 emission reduction in CO2 shipping infrastructure

There is an increased focus on the reduction of anthropogenic emissions of CO2 by means of CO2 capture processes and storage in geological formations or for enhanced oil recovery. The necessary link between the capture and storage processes is the transport system. Ship-based transport of CO2 is a better option when distances exceed 350 km compared to an offshore pipeline and offers more flexibility for transportation, unlike pipelines which require a continuous flow of compressed gas. Several feasibility studies have been undertaken to ascertain the viability of large-scale transportation of CO2 by shipping in terms of the liquefaction process, and gas conditioning, but limited work has been done on reducing emissions from the ship’s engine combustion.From 2020, ships operating worldwide will be required to use fuels with 0.5% or lower sulphur content (versus 3.5% now) or adopt adequate measures to reduce these emissions. This study explores the use of the solvent-based post-combustion carbon capture and storage (CCS) process for CO2 and SO2 capture from a typical CO2 carrier. A rate-based aqueous ammonia process model was developed, validated, then scaled up and modified to process flue gas from a Wartsila 9L46 F marine diesel engine. Different modes of operation of the carrier were analysed and the most efficient mode to operate the CCS system is during sailing. The heat recovered from the flue gas was used for solvent regeneration. A sensitivity study revealed that the 4 MWth supplied by the “waste heat recovery” system was enough to achieve a CO2 capture level of 70% at a solvent recirculation flowrate of 90–100 kg/s. The removal of SO2 by the ammonia water solution was above 95% and this led to the possibility of producing a value-added product, ammonium sulphate. The boil-off gas and captured emitted CO2 were recovered using a two-stage re-liquefaction cycle and re-injected into the cargo tanks, thereby reducing extra space requirements on the ship.

Flexible operation of coal-fired power plant integrated with post-combustion CO2 capture

For environmental protection, solvent-based post-combustion carbon capture (PCC) process has been applied to the coal-fired power plant as an end-of-pipe approach. Power plant needs to provide steam for PCC process and this will significantly influence the net power output. In this regard, this paper aims to: 1) provide an integrated model of small-scale PCC process with small-scale coal-fired power plant; 2) propose feed-back control structures for the integrated system and 3) develop a feed-forward controller to manipulate the steam draw-off flowrate in order to satisfy the rapid response to grid demand. Case studies were presented to investigate the system performance in the face of setpoints tracking and response to load change. The simulations were carried out in gCCS toolkit. Results demonstrate that the feed-forward controller can satisfactorily lower the time needed for power output target tracking.

CO2/SO2 Emission Reduction in CO2 Shipping Infrastructure

There is an increased focus on the reduction of anthropogenic emissions of CO2 by means of CO2 capture processesand storage in geological formations or for enhanced oil recovery. The necessary link between the capture andstorage process is the transport system. Ship-based transport of CO2 is a better option when distances exceeds 350 km compared to an offshore pipeline and offers more flexibility for transportation unlike pipelines which require a continuous flow of compressed gas. Several feasibility studies have been undertaken to ascertain the viability of large scale transportation of CO2 by shipping in terms of the liquefaction process, and gas conditioning, but limited work has been done on reducing emissions from the ship’s engine combustion. From 2020, ships operating worldwide will be required to use fuels with 0.5% or less sulphur content (versus 3.5% now) or adapt adequate measures to reduce these emissions. This study explores the use of the solvent-based post-combustion carbon capture and storage (CCS) process for CO2 and SO2 capture from a typical CO2 carrier. A rate based aqueous ammonia process model was developed, validated, then scaled up and modified to process flue gas from a Wartsila 9L46F marine diesel engine.Different modes of operation of the carrier were analysed and the most efficient mode to operate the CCS system is while it is sailing. The heat recovered from the flue gas was used for solvent regeneration. A sensitivity study revealed that the 4 MWth supplied by the “waste heat recovery” system was enough to achieve a CO2 capture level of 70% at a solvent recirculation flowrate of 90-100 kg/s. The removal of SO2 by the ammonia water solution was above 95% and this led to the possibility of formating a value-added product, ammonium sulphate. The boil-off gas and captured emitted CO2 were recovered using a two stage re-liquefaction cycle and re-injected into the cargo tanks; thereby reducing extra space requirements on the ship.

Application of piece-wise linear system identification to solvent-based post-combustion carbon capture

Solvent-based post-combustion carbon capture (PCC) is currently the most promising method to reduce CO2 emission. To achieve a plant-wide controller for flexible operation, it is necessary to develop a data-driven model to understand the dynamic characteristics of PCC plant. This paper aims to: (i) carry out system identification to develop a data-driven model and (ii) provide insights into the nonlinear dynamics among the key variables from the PCC process in a wide operating range. These key variables include: CO2 capture rate, reboiler temperature, condenser temperature and lean solvent temperature. Pilot-scale PCC process implemented in gCCS was used to generate simulation data for system identification and model comparison. Linear single-input-single-output (SISO) transfer function models were firstly developed at different capture rates. Open loop step tests on identified models were then introduced to report the dynamics of key variables in various operating conditions and to indicate the level of system nonlinearity graphically. The nonlinearity analysis was carried out to investigate the system nonlinearity distribution in a quantitative manner. Based on the nonlinearity analysis, a multi-input-multi-output (MIMO) piece-wise model was proposed to simulate the nonlinear characteristics of PCC plant. The piece-wise model shows a satisfactory agreement with gCCS simulation data. Results of this study successfully demonstrate the nonlinear behavior of the solvent-based PCC process, which can be applied in the design of flexible plant-wide controllers.

Review of dynamic modelling, system identification and control scheme in solvent-based post-combustion carbon capture process

Solvent-based post-combustion carbon capture (PCC) process is widely viewed as the most viable option for reducing CO2 emission. This technology has been deployed globally and many researches have been conducted in this area. In this paper, current status of dynamic modelling, system identification and control scheme of solvent-based PCC process is reviewed. Different research directions of these areas are discussed to conclude the existing challenges. Based on this, this paper is also trying to provide potential solutions as possible pathways for flexible and economical operation.

Study of solvent-based carbon capture for cargo ships through process modelling and simulation

Controlling anthropogenic CO2 emission is crucial to mitigate global warming. Marine CO2 emissions accounts for around 3% of the total CO2 emission worldwide and grows rapidly with increasing demand for passenger and cargo transport. The International Maritime Organization (IMO) has adopted mandatory measures to reduce greenhouse gases (GHGs) emissions from international shipping. This study aims to explore how to apply solvent-based post-combustion carbon capture (PCC) process to capture CO2 from the energy system in a typical cargo ship and to evaluate the cost degrees of different integration options through simulation-based techno-economic assessments. The selected reference cargo ship has a propulsion system consisting of two four-stroke reciprocating engines at a total power of 17MW. The study first addressed the challenge on model development of the marine diesel engines and then developed the model of the ship energy system. The limitations of implementing onboard carbon capture were discussed. Two integration options between the ship energy system and the carbon capture process were simulated to analyse the thermal performance of the integrated system and to estimate equipment size of the carbon capture process. It was found that the carbon capture level could only reach 73% when the existing ship energy system is integrated with the PCC process due to limited heat and electricity supply for CCS. The cost of CO2 captured is around 77.50 €/ton CO2. With installation of an additional gas turbine to provide extra energy utilities to the capture plant, the carbon capture level could reach 90% whilst the cost of CO2 captured is around 163.07 €/ton CO2, mainly because of 21.41% more fuel consumption for the additional diesel gas turbine. This is the first systematical study in applying solvent-based carbon capture for ships, which will inspire other researchers in this area.