Search

Ionic liquids (ILs) as promising green solvents were first proposed to extract polycyclic aromatic hydrocarbons (PAHs) from fluid catalytic cracking (FCC) diesel. The COSMO‐RS model was used for preliminary screening of IL extractants. The liquid–liquid equilibrium (LLE) experiments were performed to show that the IL [BMIM][BF4] has a high selectivity for the model oil system. Further, the LLE experimental results show that the solubility of 1‐methylnaphthalene in [BMIM][BF4] is relatively low, while the IL exhibits a high selectivity of n‐hexadecane to 1‐methylnaphthalene. This means that the use of [BMIM][BF4] can obtain the high‐purity products when considering the almost nonvolatility of IL. Compared to the benchmark process, the multistage countercurrent–reflux extraction process can improve the PAHs purity by about 2% at the expense of 5.06% total annual cost and 6.42% energy consumption, rendering the use of IL to extract PAHs from FCC diesel more feasible in industry. [ABSTRACT FROM AUTHOR]

Hydrogen is a key raw material for many chemical processes and a clean fuel for various power generation strategies. Coal-to-hydrogen (CTH) conversion is an alternative way to produce hydrogen that is applicable to the abundant coal reserves in China. The use of fossil energy has contributed to severe environmental problems, which drives the development of potential hydrogen production processes. Biomass is a promising renewable energy as well as an attractive resource for producing hydrogen, and it may address some of these environmental problems. In this paper, the simulation results of the biomass-to-hydrogen (BTH) and CTH processes were validated using available experimental data from the literature. Based on the simulation results, a techno-economic analysis was conducted from the viewpoints of the first and second laws of thermodynamics. The techno-economic analysis included determination of the energy efficiency, material consumption, total capital investment, production cost and carbon tax. The energy efficiencies of BTH and CTH were 37.88% and 37.82%, respectively. The BTH process had a larger raw material consumption and total capital investment (TCI) than the CTH process. However, the BTH process had a lower production cost and GHG emissions than the CTH process. The results of energy analyses of the BTH and CTH processes showed that the energy efficiency can be improved from a thermodynamic perspective. The combination of thermodynamic analysis and techno-economic performance evaluation provides insights into the improvement and operation of clean hydrogen production. • Biomass-to-hydrogen (BTH) shows better performances on production cost. • Coal-to-hydrogen (CTH) shows better performances on raw material consumption and TCI. • Techno-economic performance of CTH and BTH is conducted and compared. • BTH has a superior performance in terms of its resistance to price risk than CTH process. [ABSTRACT FROM AUTHOR]

• The proposed control structure can achieve effective control and product yield. • Energy and exergy analysis are implemented to determine the passages of exergy loss. • Reactor operating conditions are optimized by sensitivity analysis. • The maximum C 6 H 11 NO yield is 99.86% and the minimum TAC is 5.988 × 107 $ per year. Cyclohexanone ammoximation is widely used as an efficient method to synthesize cyclohexanone oxime in industrial production. In this study, the cyclohexanone ammoximation production process was explored based on reaction kinetics in order to reduce its energy consumption and total annual cost. The effects of the reaction temperature, space time, and raw material ratios on the cyclohexanone oxime yield were analyzed. Under the optimized operating conditions, the maximum C 6 H 11 NO yield was 99.86%, and the minimum total annual cost was 5.988 × 107 $ per year. Dynamic control of the cyclohexanone ammoximation production process was further explored under the optimized conditions. The proposed control structure could achieve effective control and maintain the desired product yield when flow rate and composition disturbances were introduced. The energy and exergy analyses of the cyclohexanone ammoximation process show that its energy efficiency can be improved from a thermodynamic perspective. The combination of a steady state simulation and dynamic control, thermodynamic analysis, and economic performance evaluation provide insight into the improvement and operation of the cyclohexanone oxime production process. [ABSTRACT FROM AUTHOR]

Owing to the negative environmental impact and safety problems of fossil fuel resources, chemical processes based on renewable energy have been extensively studied for further development. In this study, the thermodynamic, economic, and environmental performances of biomass-to-hydrogen (BTH) conversion were assessed using corn straw as a raw material. Further, the process used to achieve BTH conversion with/without carbon capture and storage (CCS) was evaluated and analyzed in this study. According to the simulation results, the economic and environmental properties of BTH processes using different CO 2 capture rates were evaluated via thermodynamics and life cycle assessment. Compared with the biomass hydrogen production process without CCS, the EC of the BTH process with CCS decreased by 17%. However, the total investment and production cost of biomass hydrogen production with CCS increased by 1.3% and 14.6–19.4%, respectively. The energy efficiency of BTH conversion with CCS was 17% lower than that of BTH conversion without CCS. Further, the payback period of the BTH process performed with CCS was approximately 5–6 years. According to the energy consumption and the economic and environmental performances, BTH conversion with a CO 2 capture rate of 80% is a appropriate CCS system for CO 2 capture. The life cycle assessment of BTH conversion demonstrates that the BTH system with CCS can result in negative greenhouse gas emissions. The development of the BTH process using CCS is thus of great significance for achieving carbon neutralization. [Display omitted] • Cradle-to-grave life cycle analysis is carried out for BTH with or without CCS. • Techno-economic performances of the BTH processes with different carbon capture rates are compared. • BTH process with CCS can realize negative emissions of greenhouse gases. • BTH with a carbon capture rate of 80% is a more appropriate CCS system for CO 2 capture. [ABSTRACT FROM AUTHOR]

• EDWC-TED using ionic liquid-base mixed solvent is a beneficial energy saving strategy. • EDWC-TED using ionic liquid-base mixed solvent could achieve 7.81% TAC savings. • EDWC-TED using ionic liquid-base mixed solvent could energy-saving 4.52%. To further reduce the energy consumption, investment and operating costs of the extractive distillation (ED) process, this study focuses on the process intensification by the combination of ionic liquids-based mixed entrainers and dividing wall column (DWC) for methanol/ethanol/water separation process. Based on the process simulation results, energy efficiency, economic and environmental impact assessments were carried out and compared with the benchmarked ED process using ethylene glycol as entrainer. The ternary ED process using the ionic liquids-based mixed entrainer can reduce the total annual cost (TAC) by about 5.98% and the energy consumption by 2.93%. The TAC and energy consumption for the proposed ternary ED process with DWC using the ionic liquids-based mixed entrainer can be reduced by 7.81% and 4.52%, respectively. The novel ED process shows the high energy efficiency, low economy cost and low CO 2 emissions with a great industrial application prospect when compared to the benchmarked process. [ABSTRACT FROM AUTHOR]

Methanol is an important basic industrial chemical. At present, coal-to-methanol (CTM) production is the main mode of production used in China, but the mining of coal has almost irreversible environmental impacts. Thus, producing methanol by replacing coal with abundant biomass resources has been identified as a promising alternative approach. Before large-scale application, it is necessary to study the environmental impacts and energy consumption of biomass-to-methanol (BTM) methods to evaluate their capacity to replace CTM production. In this work, CTM and BTM processes are modeled and simulated. Life cycle energy consumption, global warming potential, acidification potential and human toxicity potential are studied for the two processes from a life cycle assessment perspective. The results show that methanol synthesis and purification units constitute the most energy intensive facets of methanol production. Under the same production capacity, the life cycle energy consumption of BTM processes is lower than that of CTM processes and offers great advantages in terms of environmental impacts, especially in reducing greenhouse gas emissions. A sensitivity analysis identifies pipeline transport as an energy efficient and clean mode of long-distance methanol transport. From comparative results, using biomass resources instead of coal to produce methanol is identified as a feasible alternative. • A comparative life cycle assessment of CTM process and BTM process. • The subunits of methanol production are analyzed from the perspective of life cycle assessment. • Sensitivity analysis is used to evaluate the mode of methanol transportation. • BTM process has high GHG abatement potential. [ABSTRACT FROM AUTHOR]

In this study, the techno-economic, energy consumption (EC), and environmental performances of biomass-to-hydrogen (BTH) production with/without methane tri-reforming (MTR) from corn straw were studied. The techno-economic analysis includes an assessment of the energy efficiency, MTR operating conditions, total capital investment (TCI), production cost (PC), and payback period. The BTH energy efficiency with MTR is 17.08% higher than that without MTR. The Claus unit is the largest contribution unit of energy loss. The reaction temperature and operating pressure of one MTR unit are 800 °C and 0.1 MPa, respectively. Compared with BTH without MTR, the TCI of BTH with MTR increased by 10.97%, and the PC decreased by 10.12%. The static payback period of BTH with MTR is approximately 4.72 yr. BTH without MTR exhibits 3.09% less EC and 7.85% greenhouse gas emissions than that of BTH with MTR. The life cycle analysis of the BTH process illustrates that the BTH with MTR can realize negative carbon dioxide (CO 2) emissions when considering the natural carbon cycle. The evaluation method combines a thermodynamic analysis with a life cycle assessment, which is significant for the development of clean hydrogen production technology with low carbon and high energy savings. • Cradle-to-grave life cycle analysis is carried out to BTH with/without MTR process. • Techno-economic performance of BTH with/without MTR process is compared. • BTH with MTR process can realize negative emission of greenhouse gases. • The MTR unit realizes internal self-heating and reduces energy consumption. [ABSTRACT FROM AUTHOR]

Developing coal-to-hydrogen (CTH) process is a major way to relieve the conflict between hydrogen supply and demand. The environmental problems caused by the utilization of fossil energy have driven the progress of alternative hydrogen production processes. Biomass energy, as an attractive renewable hydrogen resource, can solve some environmental problems. In this study, CTH and biomass-to-hydrogen (BTH) processes are modeled and studied. Based on the simulation results, the life cycle analysis energy consumption (EC) and greenhouse gas (GHG) emissions of CTH and BTH processes are performed. The system life cycle boundary includes raw material production (or collection); transportation; synthesis gas generation; hydrogen purification; hydrogen transportation and application. The results show that the EC of the BTH process is 75.4% lower than the corresponding value of CTH process. GHG emissions of BTH process are 89.6% lower than corresponding values of CTH process. In addition, sensitivity analysis shows that pipeline transport is the most environmentally friendly transport mode. Gasification temperature is in the range of 1400–1500 °C, the system achieves the highest energy efficiency and the lowest GHG emissions. Suggestions were proposed for the policy formulation of the sustainable development of the hydrogen industry, which is of great significance to reduce GHG emissions and improve energy efficiency. • Cradle-to-grave life cycle analysis is carried out to the CTH and BTH processes. • The optimal gasification temperature and hydrogen transport model are obtained. • Compared with CTH, BTH shows better performances on life cycle EC and GHG emissions. • Lower LCEs demonstrate the promising of the BTH process. • Suggestions are given to reduce energy consumption and environmental impact. [ABSTRACT FROM AUTHOR]

• An innovative technique for efficiently treating pyridine and phenol in coal gasification wastewater has been proposed. • The optimal entrainer was determined from various angles using VLE, COSMO-SAC and quantum chemical calculations. • The relationship between separation sequence and energy consumption is explored. • The HI-DWC-EPSDP-SE process demonstrates optimal economic, environmental, and thermodynamic efficiency performance. The phenol and pyridine of coal gasification wastewater (CGW) are extremely toxic pollutants. Thus, there is an urgent need to develop a new process for the effective treatment of phenol and pyridine in CGW. Vapor-liquid equilibrium (VLE) and COSMO-SAC model analysis were used to select the entrainer, and interaction region indicator analysis was applied to elucidate the separation mechanism. Aiming to minimize total annual cost (TAC), the optimal process parameters were established through a sequential iterative procedure; extractive pressure-swing distillation process: separation sequence E (EPSDP-SE) process exhibiting the best performance. Heat integrated extractive pressure-swing distillation with dividing wall column process: separation sequence E (HI-DWC-EPSDP-SE) was developed by integrating a thermal process and dividing wall distillation technology. In comparison to EPSDP-SE, HI-DWC-EPSDP-SE achieved reductions of 26.97% in TAC, 38.89% in total operation cost, and 6.21% in total capital cost. Additionally, it lowered total acid gas emissions and energy consumption by 39.98% and enhanced thermodynamic efficiency by 54.72%. The HI-DWC-EPSDP-SE process showcases exceptional separation performance in terms of economy, energy consumption, and environmental impact. [ABSTRACT FROM AUTHOR]

A clean and sustainable process for separating n-heptanol/n-hexanol/water industrial mixing system by extractive distillation via mixing organic solvent with ionic liquid as an entrainer was proposed. The mechanism of intermolecular microscopic interaction was explored by quantum chemistry calculation. By using multi-objective optimization, the optimal operating parameters of the process were obtained. In addition, process intensification technology was introduced, which improved the problems of high cost and high energy consumption in the conventional extractive distillation process. Finally, multiple performances were evaluated and analyzed for different processes. It was found that the coupled heat integration and heat pump technology to assist the extractive distillation process saved 10.45% in terms of economy, reduced gas emissions by 49.00%, and reduced energy consumption by 48.99% compared to the basic extractive distillation process. This confirmed the reliability and feasibility of implementing the process intensification technology. This work demonstrates the application of organic solvent mixed with ionic liquid as entrainer and process intensification technology in the extractive distillation process, providing guidance and reference for the design of the extractive distillation process. [ABSTRACT FROM AUTHOR]

• Efficient separation technology for the fermentation mother liquor to n-butanol was proposed. • Molecular polarity and weak interaction analysis revealed the extractive separation mechanism. • TCEDP is a typical process intensification strategy with economic, energy and environmental benefits. To solve the problems of difficult separation of azeotropes and high energy consumption in the preparation of n-butanol from the fermented mother liquor, this study focused on the separation process integration of water/acetone/ethanol/n-butanol mixture based on the combination of mixed entrainer and thermally coupled distillation technology. Based on quantum chemical calculations, the molecular polarity and weak interaction between the entrainer and the mixture to be separated were studied at the molecular scale, and the separation mechanism of extractive distillation was revealed. Based on the simulation results, the three different configurations' process performance was evaluated and compared to the benchmark conventional extractive distillation process with ethylene glycol as the entrainer. The thermally coupled extractive distillation process with mixed entrainers can reduce the total annual cost by about 39.87%, reduce energy consumption and acid gas emissions by 46.53%, and improve the thermodynamic efficiency by 47.57%. The thermally coupled extractive distillation process with mixed entrainers is an economical, energy-saving, and environmentally friendly production scheme superior to the conventional extractive distillation process. The thermally coupled extractive distillation process, as an essential energy-saving technology for producing n-butanol from fermentation mother liquor, has broad development prospects. [ABSTRACT FROM AUTHOR]