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The global plastic sector urgently needs a circular economy and decarbonization since excessive plastic use is aggravating plastic pollution and climate change. In this regard, a novel strategy was proposed to close both the plastic loop and carbon loop using carbon capture, utilization, and storage (CCUS), which involves recycling waste plastic into adsorbents for CO 2 capture and converting the captured CO 2 back into new plastic. This plastic-CO 2 -plastic route applied in polyurethane was assessed through life cycle assessment and a new indicator, carbon closure efficiency (CCE), was proposed to quantify the extent to which a carbon loop is closed. Results indicate a negative emission of -9.57 kg CO 2 eq/kg polyurethane. However, CCUS amplifies other impacts, including primary energy demand, water use, etc. Chemical feedstocks and adsorbent preparation are crucial factors for most environmental impacts. CCUS-based strategy far surpasses chemical recycling in CCE score, highlighting its effectiveness in closing the carbon loop. [Display omitted] [ABSTRACT FROM AUTHOR]

CO 2 fixation from seawater is an effective way to mitigate climate change and has gained widespread attention in recent years. However, the existing research mostly involves stoichiometric bases and bipolar membrane electrodialysis methods, and the performance of direct seawater electrolysis for CO 2 fixation is presented with limited studies and rare research data. The performance evaluation on CO 2 fixation based on the technology of direct seawater electrolysis is presented in this paper. Energy consumption, decalcification rate, and calcium carbonate production rate are employed as performance indexes to assess the feasibility of CO 2 fixation through direct electrolysis of seawater. The simulation method is adopted in this paper, with validation based on data from experiment. As a result, the minimum energy consumption for per amount of calcium carbonate deposited ranges from 557.82 to 730.06 kJ/mol CaCO 3 at the seawater flow rate range of 0.01–0.1 L/s, which has an advantage over other electrochemical CO 2 capture method. Additionally, the decalcification rate and calcium carbonate production rate can reach a maximum of 100% and 0.36 mmol/s respectively. The conclusions presented in this paper can serve as a valuable guide for conducting large-scale evaluations or application analyses. [Display omitted] • A novel method for CO 2 fixation and seawater decalcification is proposed. • Direct electrolysis of seawater is applied as a substitute for chemical reagent. • The model of electrolyzer is established and its reliability is validated. • Performance parameters of the proposed method is analyzed. • The energy consumption range is 557.82–730.06 kJ/mol CaCO 3. [ABSTRACT FROM AUTHOR]

This study explores the impacts of materials, such as adsorbents and electrodes, on the energy efficiency of a 4-step ESA cycle for CO 2 capture. Three types of adsorbents including activated carbon honeycomb monolith (ACHM) and two hybrid adsorbents are compared, and two kinds of electrodes such as aluminum and brass are combined for comparative analysis. Process description of ESA cycle, including feed, electrification, electrification with purge and cooling, is presented via the adsorption isotherm diagram. By the theory of thermodynamic carbon pump, sensitivity analysis of cycle parameters is evaluated in terms of the second-law efficiency (Eff 2nd ) and the electrical heating efficiency (Eff ele ). The results show that Eff 2nd of the employed adsorbents is in the range of 1.17%–6.15%, and Eff ele of the selected electrodes is between 27.46% and 60.91%. Among the three adsorbents, Eff 2nd of ACHM is the lowest one compared to the others. Similarly, Eff ele of the combination with brass is superior to that of the groups with aluminum. However, the actual efficiency of ESA cycle is the production of both Eff 2nd and Eff ele , which is approximately 1.03%–3.66%. Typical measures are proposed to reduce the heat loss of the adsorbents and electrodes as well for future work. [ABSTRACT FROM AUTHOR]

Currently, temperature swing adsorption (TSA) process is considered as a promising option for CO 2 capture due to its low energy consumption and low operating cost. For a deeper understanding on energy-efficiency performance of TSA and possible integration potential with solar source, the energy-efficiency analysis on TSA cycle is conducted by using a numerical model. The developed model, which can achieve an accepted trade-off between calculation cost and quick response for the engineering application, can be simplified into two main parts: the process model for 4 steps in the cycle and Sips isothermal model for prediction on the adsorption equilibrium. The minimum separation work and the second-law efficiency are applied as evaluation indicators in the preliminary. The numerical calculation are conducted for a binary CO 2 /N 2 feed gas using zeolite 13X as adsorbents, with a temperature range (300K-440K) between heating and cooling sources. The results show that at 310K T L , the second-law efficiency of the TSA has a range of 4.51%-17.24% with T H from 380K to 420K. Moreover, the greater the temperature difference (△T) between adsorption temperature and desorption temperature, the higher the second-law efficiency. The model system proposed in this work shows a great potential on energy-saving and the possible solar integration solution. [ABSTRACT FROM AUTHOR]

The concentration of CO 2 in the atmosphere, which causes a serious impact on the climate, provided a development space for the carbon capture technology. The adsorption technology for carbon dioxide capture has been extensively studied because of its low energy consumption. The experimental study on carbon dioxide capture adsorption technology, which commonly require enough time-consuming and funding, determines the significance of numerical investigation. In this paper, the progress on numerical investigation and mathematical model of heat transfer and mass transfer in the adsorption chamber is reviewed. The simplified method of the adsorption process is analyzed in the following aspects: the mass transfer process is commonly simplified as the adsorption kinetic model and the adsorption equilibrium model, the pressure loss is expressed by the bed pressure drop, and the heat transfer process is analyzed by the temperature distribution in the adsorption chamber. The construction and application of various researchers’ models are finally summarized in this paper. [ABSTRACT FROM AUTHOR]

Hydrate-based CO 2 capture (HBCC) technology, which is a promising alternative method to CO 2 capture, has received increasing attention in recent decades as it has mild operating conditions and unique separation mechanism. This paper summarises several available methods on improving the separation performance of HBCC technology, mainly including chemical additives and improvement of capture process. The chemical additives are generally divided into two classes: thermodynamic promoters (THF, TBAB, TBAF, CP, C 3 H 8 ) and kinetic promoters (SDS, DTAC). In addition to the common single stage process, the multistage process and hybrid conceptual process coupled with membrane separation are developed to obtain more concentrated CO 2 . Then the evaluation indicators of separation performance are introduced: CO 2 recovery and separation factor. Moreover, the separation performance of CO 2 capture from either post-combustion flue gas or pre-combustion fuel gas is discussed and the development direction in the future is highlighted as well. [ABSTRACT FROM AUTHOR]

Solvent-based Post-combustion Carbon Capture (PCC), which can reduce CO 2 emissions from coal-fired power plants, is one of the most advanced mature Carbon Capture and Storage (CCS) technologies at present. Two problems limit its development. One is the output reduction of power plant due to the steam extraction from turbine. The other is a large amount of water consumption for the evaporation of the solution in the absorber and desorber. In this paper we propose an integrated system to reduce the steam extraction from turbine and to produce freshwater by using solar thermal energy. The new system produces more electricity and freshwater during the daytime, and uses the steam extraction to reduce CO2 emissions at night. A techno-economic feasibility study is performed as a case study for a 300 MWe coal-fired power plant assisted by solar desalination. As for the potential impact parameters, the local climatic conditions and CO 2 capture rate are discussed. Low-cost collectors and desalting equipment would make the technology more cost-effective. [ABSTRACT FROM AUTHOR]

As an end user of energy products, carbon dioxide capture and storage (CCS) system commonly requires a significant amount of energy to sustain a steady operation. As a renewable energy source, solar energy can supply plenty of thermal energy in different grades through various types of solar collector. Between the demand and supply sides, several technologies of solar thermal engineering can be applied as a bridge for an energy efficient design. In this paper, a technological framework for the energy efficiency in post-combustion CO 2 capture is further discussed as a second section of the two-part study. Based on existing research, several possible options of alternative energy supply to CCS system are analyzed, particularly for solar thermal energy. Moreover, some key design issues for the solar-assisted CCS system, such as integrated solar reactor with the regeneration component, are discussed as well. [ABSTRACT FROM AUTHOR]

Representative carbon dioxide capture and storage (CCS) system of the post-combustion, no matter it employs adsorption, absorption or cryogenics separation technologies, commonly requires significant amounts of energy for the fundamental operation. Thus, energy consumption and related cost rise are primary challenges for the promotion of post-combustion technology. Solar thermal energy has already been widely used as an effective and clean energy source in industrial applications for drying, heating and even cooling since the last century. Various options of solar collector, such as flat plate type, evacuate tube type, and parabolic trough type, facilitate a comprehensive energy supply in different energy quality grades. In this paper, a technological framework for the energy efficiency in post-combustion CO2 capture is briefly presented for a connection between the energy demand of a CCS system and the energy supply of solar thermal engineering. The match performance between solar thermal utilization systems and CCS system is discussed in terms of energy form of the demand side (CCS), energy grades of supply sides (solar collector), and possible dynamic adjustment [ABSTRACT FROM AUTHOR]

A novel system integrating solar Organic Rankine Cycle (ORC) into a power plant with amine-based chemical absorption for CO 2 capture is proposed. The condensation heat of ORC provides the required heat for solvent regeneration, which avoids the energy penalty caused by the steam extraction traditionally. The cascade utilization of solar energy is realized through a combined supply of power generation and condensation heat. From the aspects of technology and economics, a performance analysis is presented to compare the proposed system and three other systems based on a 300 MWe power plant. The proposed system shows better performance than that of reference systems in the power generation and emission reductions. Economic evaluation was conducted in terms of levelized costs of electricity (LCOE) and cost of CO 2 removed (COR). In order to achieve lower LCOE and COR compared to the power plant integrated with solar assisted post-combustion CO 2 capture (PCC), the price of ORC has to be lower than 1284.46 USD/kW under the conditions that the price of the solar field is 120 USD/m 2 . It is believed that the proposed system has a satisfied potential to meet the thermal demand for the solvent regeneration in the power plant with PCC. [ABSTRACT FROM AUTHOR]