Co-production System Research Articles

Thermodynamic analysis and optimal design of an innovative CaC2 and electricity co-production system through air separation and energy storage

Large-scale liquid air energy storage is a solution to achieve the goal of net zero carbon emission. However, there is currently no mature application and more research in realistic application cases is needed. Facing the application in future industrial scenarios with high levels of renewable energy penetration, this study couples the liquid air energy storage to oxygen-thermal calcium carbide manufacturing industry by sharing an air separation unit. It is a chemical material and electricity co-production concept to reduce the specific energy consumption of calcium carbide and manage the uncertainties of power supply and demand. Thermodynamic and sensitivity analyses are conducted to understand the system performance and interactions between each process. In the chemical process, the production and purity of calcium carbide are 28.56 kg/s and 66.6 % respectively, and the specific energy consumption is 246.2 kWh/t-CaC2. Material matching, equipment sharing, and thermal integration make the round-trip efficiency of the proposed system reach 56.8 %. An artificial neural network-based process optimization is performed to establish the optimal design. The proposed system presents 11 % higher round-trip efficiency and 2–3 times the energy storage density in comparison to stand-alone liquid air energy storage systems.

Membrane-Free Electrocatalytic Co-Conversions of PBS Waste Plastics and Maleic Acid into High-PuritySuccinic Acid Solid.

Plastic pollution, an increasingly serious global problem, can be addressed through the full lifecycle management of plastics, including plastics recycling as one of the most promising approaches. System design, catalyst development, and product separation are the keys in improving the economics of electrocatalytic plastics recycling. Here, a membrane-free co-production system was devised to produce succinic acid (SA) at both anode and cathode respectively by the co-electrolysis of polybutylene succinate (PBS) waste plastics and biomass-derived maleic acid (MA) for the first time. To this end, Cr3+-Ni(OH)2 electrocatalyst featuring much enhanced 1,4-butanediol (BDO) oxidation reaction (BOR) activity has been synthesized and the role of doped Cr has been revealed as an "electron puller" to accelerate the rate-determining step (RDS) in the Ni2+/Ni3+ cycling. Impressively, an extra-high SA production rate of 3.02 g h-1 and ultra-high apparent Faraday efficiency towards SA (FEapparent=181.5%) have been obtained. A carbon dioxide-assisted sequential precipitation approach has been developed to produce high-purity SA and byproduct NaHCO3 solids. Preliminary techno-economic analysis demonstrates that the reported system is economically profitable and promising for future industrial applications.

A Co-production system of cement and methanol: Unveiling its advancements and potential

Both the cement and methanol sectors face increasing pressure to reduce their carbon emissions to combat climate change. Coupling the production process can provide economic and environmental benefits when implementing breakthrough technologies in these industries. The advantages and application potential of the co-production system need to be assessed quantitatively in long-term decarbonization pathways. This study proposes a co-production system of cement and methanol that capitalizes on strong complementarity through bidirectional material flow. Multi-regional planning models are established to evaluate the spatiotemporal deployment of low-carbon technologies, including coupling technologies. The results demonstrate that the co-production system can achieve a 6.6% higher emissions reduction and a 21.2 % lower production cost of clinker by 2060 compared to implementing breakthrough technologies separately. The co-production routes may be widely distributed across China by 2060, accounting for 24.1 % of clinker output and 54.7 % of methanol output. Introducing coupling technologies can influence the industrial layout and trade patterns of China's cement and methanol sectors, carrying policy implications for the deployment of low-carbon technologies.

A clean hydrogen and electricity co-production system based on an integrated plant with small modular nuclear reactor

The present study aims to develop a novel configuration of hydrogen and electricity co-production based on a small modular nuclear reactor (SMR) by synergistically integrating the Vanadium Chloride thermochemical (V–Cl) and helium-closed Brayton cycles. For the V–Cl thermochemical cycle, a steady-state simulation model is developed for the first time in the Aspen Plus environment. The entire system is assessed thermodynamically by calculating the exergy destruction rate and exergy efficiency of major components employed in different subsections (nuclear power production, clean hydrogen production, supporting Rankine cycle, hydrogen compression, and storage) of the plant. Various parametric studies are conducted to identify the scope of improvement and evaluate suitable operating parameters that exhibit optimized system performance. It is found that a maximum H2 production rate is achieved when the VCl4 flow is 3.6 kmol/h. A specific hydrogen production rate of 9.63 g/kWh is achieved. The reduction reactor and Deacon reactors are responsible for the highest and lowest exergy destruction with a value of 155.46 kW and 37.60 kW accounting for 49 % and 11.86 % of the overall exergy destruction within the V–Cl cycle. The share of power production from the secondary Rankine cycle in the overall hydrogen compression train is 16.48 %. The parametric study results show that with an outlet helium pressure of 15 bar, the overall work output and electrical efficiency peaked with a value of 4.6 MW and 15.64 % respectively. The overall energy and exergy efficiencies of the proposed system are found to be 16.94 % and 21.42 % respectively.

Integrated scheme analysis and thermodynamic performance study of advanced nuclear-driven hydrogen-electricity co-production systems with iodine-sulfur cycle and combined cycle

A promising method for massive clean hydrogen production is the Very High Temperature Reactor (VHTR)-driven Nuclear Hydrogen Production (NHP) system using the Iodine–Sulfur (IS) cycle. Research on integrated scheme and thermodynamic performance of the VHTR-driven NHP system using the IS cycle has, however, received little attention up to this point, particularly when the combined cycle is employed as the power generation cycle. In order to bridge this research gap, this work proposed and studied two distinct VHTR-driven hydrogen-electricity co-production systems with the IS cycle and combined cycle: the independent operating system and the coupled operating system. Thermodynamics was used to model these two systems, and system thermodynamic performance was examined under the baseline operating conditions. A parametric study was further conducted on how two important operating parameters affected system thermodynamic performance. The primary findings indicated that the coupled operating system outperformed the independent operating system in terms of thermodynamic performance. Additionally, both the independent and coupled operating systems could produce hydrogen at the same rate of 289.8 mol/s, with net electrical power outputs of 61.07 MW and 102.7 MW, respectively, under the baseline operating conditions. Furthermore, it was discovered that a rise in the mass flow ratio for both operating systems would result in a notable reduction in system efficiency.

Taurine-mediated gene transcription and cell membrane permeability reinforced co-production of bioethanol and Monascus azaphilone pigments for a newly isolated Monascus purpureus

BackgroundTaurine, a semi-essential micronutrient, could be utilized as a sulfur source for some bacteria; however, little is known about its effect on the accumulation of fermentation products. Here, it investigated the effect of taurine on co-production of bioethanol and Monascus azaphilone pigments (MonAzPs) for a fungus.ResultsA newly isolated fungus of 98.92% identity with Monascus purpureus co-produced 23.43 g/L bioethanol and 66.12, 78.01 and 62.37 U/mL red, yellow and orange MonAzPs for 3 d in synthetic medium (SM). Taurine enhanced bioethanol titer, ethanol productivity and ethanol yield at the maximum by 1.56, 1.58 and 1.60 times than those of the control in corn stover hydrolysates (CSH), and red, yellow and orange MonAzPs were raised by 1.24, 1.26 and 1.29 times, respectively. Taurine was consumed extremely small quantities for M. purpureus and its promotional effect was not universal for the other two biorefinery fermenting strains. Taurine intensified the gene transcription of glycolysis (glucokinase, phosphoglycerate mutase, enolase and alcohol dehydrogenase) and MonAzPs biosynthesis (serine hydrolases, C-11-ketoreductase, FAD-dependent monooxygenase, 4-O-acyltransferase, deacetylase, NAD(P)H-dependent oxidoredutase, FAD-dependent oxidoredutase, enoyl reductase and fatty acid synthase) through de novo RNA-Seq assays. Furthermore, taurine improved cell membrane permeability through changing cell membrane structure by microscopic imaging assays.ConclusionsTaurine reinforced co-production of bioethanol and MonAzPs by increasing gene transcription level and cell membrane permeability for M. purpureus. This work would offer an innovative, efficient and taurine-based co-production system for mass accumulation of the value-added biofuels and biochemicals from lignocellulosic biomass.

A Comprehensive Assessment of the Carbon Footprint of the Coal-to-Methanol Process Coupled with Carbon Capture-, Utilization-, and Storage-Enhanced Oil Recovery Technology

The process of coal-to-methanol conversion consumes a large amount of energy, and the use of the co-production method in conjunction with carbon capture, utilization, and storage (CCUS) technology can reduce its carbon footprint. However, little research has been devoted to comprehensively assessing the carbon footprint of the coal-to-methanol (CTM) co-production system coupled with CCUS-enhanced oil recovery technology (CCUS-EOR), and this hinders the scientific evaluation of its decarbonization-related performance. In this study, we used lifecycle assessment to introduce the coefficient of distribution of methanol and constructed a model to calculate the carbon footprint of the process of CTM co-production of liquefied natural gas (LNG) as well as CTM co-production coupled with CCUS-EOR. We used the proposed model to calculate the carbon footprint of the entire lifecycle of the process by using a case study. The results show that the carbon footprints of CTM co-production and CTM co-production coupled with CCUS-EOR are 2.63 t CO2/tCH3OH and 1.00 t CO2/tCH3OH, respectively, which is lower than that of the traditional CTM process, indicating their ability to achieve environmental sustainability. We also analyzed the composition of the carbon footprint of the coal-to-methanol process to identify the root causes of carbon emissions in it and pathways for reducing them. The work described here provided a reference for decision making and a basis for promoting the development of coal-to-methanol conversion and the CCUS industry in China.

Thermal-driven osmosis utilizing hollow fiber membranes: Sustainable dye water treatment and electricity extraction

Excessive discharges of chemical dyes have led to severe contamination of seawater, resulting in significant ecological damage. Thermo-osmotic energy conversion technology, which purifies wastewater and generates electricity under temperature gradients, has garnered considerable interest from researchers. However, the operational efficiency of thermo-osmotic energy conversion is inherently limited by the effective membrane area, and conventional systems typically employ flat membranes as separators, resulting in suboptimal performance for the same floorage. In this study, we introduce a novel system that combines thermo-osmotic energy conversion technology with hollow fiber membranes that possess a high effective membrane area, thereby achieving optimized performance. Driven by the temperature gradient, the water in the dye solution condenses outside the membrane and converted from vapor to liquid. The continuous accumulation of condensed water generates pressure and drives a water turbine for sustainable power generation. Our results demonstrate that at temperature gradient of 40 °C, the system can achieve the power output of 16.75 Wm−3 and the freshwater production rate of 70.29 kg m−3 h−1 under ideal conditions. This study presents a novel water-electricity co-production system based on low-grade waste heat recovery for dye solution treatment, which extends the applicability of thermo-osmotic energy conversion technology and improves its practicality.

Conductive polymer protection strategy to promote electrochemical nitrate reduction to ammonia in highly acidic condition over Cu-based catalyst

Electrochemical nitrate reduction (NO3-RR) is a promising way to produce ammonia by alternating Haber-Bosch process. As one promising catalyst, copper suffers from low activity and instability in acidic electrolyte that hinders practical applications. Herein, we report a conductive polymer protection strategy by decorating polypyrrole on Cu nanoparticles (Cu-PPy), achieving high NO3-RR efficiency under strong acidic conditions. In 0.5 M H2SO4, Cu-PPy exhibits high NH3 yield rate of 0.55 mmol h−1 cm−2 with NH3 selectivity of 99.99 % and FE of 96.0 % at high NO3– conversion. Experimental and theoretical results reveal that PPy plays a pluripotent role for the enhanced NO3-RR, consisting of protecting Cu from corrosion in highly acidic electrolyte, promoting the adsorption of NO3– and NO2– in local environment, stabilizing Cu in intermediate valence state, and accelerating the electron transfer rate. Furthermore, a co-production system of NH3 and adipic acid is constructed and achieves high combined electron efficiency.

Experimental investigation on parameter optimization of liquid spectral beam splitter for continuous photocatalytic hydrogen production accompanied with photovoltaic power generation under solar full spectrum

Effective utilization of solar energy is of great significance for a sustainable future. Herein, we report a cascade system for hydrogen-electricity co-production (PH-PV) utilizing solar full spectrum. The output performance of the system can be precisely adjusted by controlling certain parameters of liquid spectral beam splitter (LSBS) which contains TiO2 nanoparticle suspension simultaneously generating hydrogen via a photocatalytic reaction process. Typically, the thickness of LSBS, the loading amount of TiO2, the flowrate of suspension and the light intensity have been investigated in detail. It is found that LSBS is necessary in our system as it could ensure the safe operation of PV while the light intensities larger than 8 suns. With the decrease of the thickness or loading amount of photocatalyst, more electricity could be produced by PV module but less hydrogen from PH module. Further increase of above two parameters simultaneously could lead to aggregation and settlement of particle suspension in LSBS, which is detrimental to the optical absorbance of the system. Besides, changing the flowrate will diversify the surface features of particles by shear-induced effect. At optimal flowrate, the particles in LSBS could exhibit oscillation characteristics under synergistic effect of shear force and gravity, which would lead to excellent light absorption and transmittance. Furthermore, an obvious gain for both hydrogen and electricity output and system efficiency could be obtained through increasing light intensity appropriately. Finally, the improved merit function (MF) was employed to evaluate the performance of hybrid system and more obvious effect of flowrate on MF value than other parameters was found. The optimal MF value of 3.07 was reached when flowrate was 60 mL/min. Our work is expected to provide important guidance for the optimization of PH-PV cascade system driven by outdoor direct solar energy.

Market optimization and technoeconomic analysis of hydrogen-electricity coproduction systems

We present an optimization framework to analyze emerging power systems technologies that coproduce power and alternative fuels. Emerging solid oxide-based systems have the potential to enable a reliable, efficient transition to cleaner energy.

Система совместного использования обедненного метана угольных пластов и биогаза для выработки электроэнергии в угольных шахтах

Purpose: Justification and development of new resource-saving technologies aimed at utilization of coal bed methane. The problem of low efficiency of utilization of lean methane-air mixtures is primarily due to the low content of methane itself, which varies significantly depending on the type of coal or concentration. This paper discusses the concept of a co-production system that mixes low-methane methane-air mixtures and biogas to generate power. Methods: Analysis of the possible volumes of utilized methane, biogas requirements and the suitability of the primary feedstock for co-generation of heat and electricity. Selection of appropriate parameters for the processes of utilization of mine methane. Analysis of the merits of the proposed method of utilization of lean coal mine methane. Results: It is recommended that biogas produced by agriculture and forestry in the vicinity of the mines be added to the dry methane stream to obtain the necessary gas concentration for electricity generation. Potential electricity production and greenhouse gas emission reductions have also been evaluated. The result shows that the co-production system can significantly improve the efficiency of poor methane-air mixtures in coal mines. Practical significance: The joint use of lean methane and biogas from straw offers practical advantages both economically, ensuring sufficient energy supply in mines, and as a foundation for broad future prospects. It allows for energy cost reduction and environmental pollution reduction, such as decreasing carbon dioxide emissions.

Optimal design and analysis of a liquid hydrogen and LNG coproduction system with multistage multicycle cascade refrigeration system

The efficient utilization of industrial by-products, such as synthetic ammonia exhaust tail gas and coke oven gas, has been neglected in China for a long time. Thus, the development of novel high-efficiency industrial by-product utilization methods is of great importance. A multistage multicycle cascade refrigeration system utilized for hydrogen liquefaction with LNG production is constructed in this paper. The industrial by-products after purification directly enter into cryogenic separation liquefaction system. Liquid hydrogen and LNG are produced after pre-cooling, separation and liquefaction respectively. Process configuration, thermodynamic analysis, optimization model with GA is conducted. The specific power consumption of the multistage multicycle cascade system is within 14.0–17.4 kWh/kmol (feed gas). The proposed process can be used in the efficient utilization of industrial by-products with high exergy efficiency (33.6%∼41.45%) and great economic benefits.

Efficient reforming of methane in a porous radiant reactor with regular structure: A novel experimental system for heat-hydrogen coproduction

As a high-energy clean fuel, hydrogen is one of the most promising energy carriers to achieve “carbon neutrality”. In order to produce hydrogen, a novel porous media heat-hydrogen coproduction system (PHH) with regular structure was built, and ceramic foam was added to improve thermal radiation performance. The effects of porous regular structure on the temperature distribution, products concentration, and thermal radiation efficiency were investigated at different operating conditions. The results indicated that the regular structure achieved higher hydrogen concentration and methane conversion efficiency than the irregular structure, especially at small-diameter pellets. Meanwhile, increasing the pellets diameter and decreasing the ceramic rings size reduced the radiation efficiency, but that improved the hydrogen production. The optimal thermal efficiency (26.5%) and radiation efficiency (33.2%) were obtained in the Ⅰ-type reactor at the equivalence ratio of 1.5. In addition, with the inlet velocity increasing from 10 to 14 cm/s, the combustion temperature and syngas energy conversion efficiency significantly increased. These results provide an essential reference for advancing the practical application of heat-hydrogen coproduction and the design of the regular structure in porous media reactor.

Demand oriented planning of methanol-dimethyl ether co-production system for CO2 reduction

This work addresses an optimal design method for a methanol-dimethyl ether co-production system with the fluctuations in supply and demand, aiming to utilize the CO2 from point sources as much as possible in actual industries. In the proposed method, a design and optimization model of the chemical co-production system is established with the aim of the lowest total annualized cost, and rigorous simulations are conducted to determine the cost flows of the operation units in the system. The optimal design, operation, and scheduling schemes of the co-production system can thus be determined by solving the proposed model. The application of the method is finally verified via an actual case study where a 330 MW off-design thermal power plant is taken as the carbon source and the product demand and price are determined according to the market. Results showed that the renewable chemical co-production system features the advantages of coping with supply and demand fluctuations by flexibly adjusting the production, storage and sale capacities of the products, thus achieving the maximum economic benefits and carbon reduction efficiency of 94.7%. The electricity consumption for electrolysis is the main contributor to the total annual cost of the system, accounting for more than 70%. Besides, expanding the capacity adjustment range of the dimethyl ether synthesis process can not only improve the ability of the system to deal with economic fluctuations but also help to reduce the capacity of storage tanks. It is foreseeable that the proposed system can be competitive in the near future with the formulation of new policies and the development of advanced technologies.

Modelling and optimization of sorption-enhanced biomass chemical looping gasification coupling with hydrogen generation system based on neural network and genetic algorithm

Chemical looping gasification of biomass (BCLG) can realize the production of pure syngas without an extra purification process. By coupling steam oxidation of oxygen carrier in BCLG, pure hydrogen can be generated meanwhile, which is a promising clean energy. An enhanced BCLG process coupling with hydrogen generation is constructed in this work, aiming to realize effective co-production of syngas and hydrogen. The coupled effects of temperature and material flows of gasifier on the gas yield, lower heating value (LHV) of syngas and gasification efficiency are numerically investigated. The effects of temperature and steam flowrate in oxidizer are changed to investigate their effects on hydrogen production. Based on the simulation results, an accurate back-propagation neural network (BPNN) is trained and tested for the performance prediction of this syngas and hydrogen co-production system. The prediction accuracy of this BPNN model is quite high with a correlation coefficient of 0.99967. Finally, the optimization of this system is conducted based on the BPNN model and genetic algorithm (GA) to make the H2/CO ratio close to 2 and maximize hydrogen production simultaneously.

Study of two innovative hydrogen and electricity co-production systems based on very-high-temperature gas-cooled reactors

Study of two innovative hydrogen and electricity co-production systems based on very-high-temperature gas-cooled reactors

Genetic engineering strategies for sustainable polyhydroxyalkanoate (PHA) production from carbon-rich wastes

Polyhydroxyalkanoates (PHAs) are promising biopolymers for biomedical applications due to their excellent biocompatibility and biodegradability. However, the high production cost mainly resulting from the pure sugar substrate limits PHA commercialization. It makes various carbon-rich wastes potential substrates for PHA production. The integration and optimization of metabolic pathways can further enhance the conversion of carbon-rich wastes to PHAs. Genetic engineering strategies focusing on carbon flux and energy metabolism have improved the PHA production capacities of targeted strains by promoting substrate assimilation, enhancing PHA synthesis, and reducing branch metabolism. CRISPR/Cas9-based systems have also served as efficient genome editing tools to improve the efficiency of metabolic modification. Genetic modification requires fitness among strains, substrates, and products. Therefore, this review outlined various efficient genetic engineering approaches to promote PHA production and discussed their feasibility in valorizing representative carbon-rich wastes. To further illustrate the widespread applicability of metabolic modification to support microbial cell factories with core PHA production, this review also involved advanced fermentation approaches and co-production systems for PHA production by engineered strains.

Stakeholder evaluation of sustainability in a community-led wastewater treatment facility in Jakarta, Indonesia

Indonesia’s severely flawed centralized wastewater treatment system has caused economic and socioeconomic losses for decades. An alternative system has been called for under a national-scale program called Sanimas or Community-Led Total Sanitation (CLTS), which would cater to 50–100 urban families in every intervention with urgent needs through the operation of a decentralized wastewater treatment system. Through household participation, this program features a co-production system wherein the national-level government initiates and provides initial funding until construction, after which a community-appointed social organization takes over. This study implemented a multicriteria approach to assess sustainability in Sanimas communities in Jakarta: 67 in Menteng (Central Jakarta) and At-Taubah in Koja (North Jakarta). Connected households and facility-operating committees were questioned separately for their opinions on six aspects that explained the survival of the establishment of a facility: technical, management, community participation, financial, institutional, and environmental. We found that although the facility’s excellence and overall satisfaction with the program were unanimous, Koja and Menteng showed substantial differences in management, institutional, and financial aspects, largely due to administrative policies, payment contributions, and committee commitments. Interviews revealed that periodic testing of the treated water was neglected, against the provided guidance. In conclusion, communities have come to focus more on the technical functionalities of the installation, regardless of the state of the management, which is indisputable not only in Menteng but also in Koja. Finally, we argue that although decentralized systems can substitute centralized systems, they still require stringent and adequate support in quality control and troubleshooting.

Design, fabrication and performance analysis of a cost-effective photovoltaic interface seawater desalination hybrid system for co-production of electricity and potable water

The combination of photovoltaic and desalination technology has attracted more and more attention because it can produce water and electricity at the same time. However, the traditional photovoltaic desalination cogeneration system has complex structure, large floor area and high investment cost, which is difficult to be applied on a small scale, especially in the fields of uninhabited islands and reefs that are inaccessible and lack investment value. In this work, we designed a new photovoltaic interface desalination coupling system, which has efficient water and electricity production. By changing the fiber structure of carbonized paper and improving the absorption rate, and optimizing the coupling structure of photovoltaic cells and interface materials, the high heat generated by photovoltaic power generation can be carried away to promote power generation and clean water generation. The practical application of the system was also tested, and the experimental results show that the evaporation efficiency of the coupled system can reach 61.09 % at a solar radiation intensity of 1000 W m−2. The corresponding evaporation rate is 0.94 kg m-2h−1. Meanwhile, the electrical efficiency can reach 11.2 %, which is 1.8 % higher than the electrical efficiency of individual PV modules. In addition, the effects of solar irradiance, ambient humidity, cell absorption rate and thermal conductivity on the evaporation efficiency and electrical efficiency of the system were studied by simulation and experiment. The performance of the PV interface solar desalination system is compared in terms of the first law of thermodynamics and external energy. Finally, the economics and the analysis of the device are performed, the cost of interface evaporation material is $1.05 m−2. Due to the low cost of raw materials, simple material preparation, high evaporation efficiency, and high electrical efficiency, the system offers the possibility of large-scale application of evaporation at the PV interface.