Supply Problems Research Articles

Optimisation design of water-fertiliser infiltration device based on TRIZ theory

Abstract This paper is based on functional flow and modular design to optimize the design of water-fertilizer integrated percolation irrigation device. Functional decomposition and the construction of functional structure model are completed, and the detection module and the delivery and irrigation module are identified as the modules to be optimized. Apply TRIZ theory to solve the power supply problem of the detection module in harsh environment and design the energy conversion structure. For the clogging problem of the irrigator, an anti-clogging design, labyrinth flow channel and unclogging pipe are proposed. For the labyrinth flow channel built-in elastic small pieces, can be compensated for the pressure of the irrigator outlet, labyrinth flow channel to form turbulence is not easy to form a blockage. When the pipe is clogged, through the inflatable unclogging pipe, to realize the clogging position of the air pressure impact, to complete the clogging unclogging.

Granular Activated Bamboo Charcoal and Silica Gel as Water Treatment Against Microbial Contaminants: A Comparative Analysis

The growing demand for clean and safe water necessitates the investigation of innovative materials that can be utilized in water treatment applications. In this regard, a simple and cost-effective water treatment method was developed to address the water supply problem in rural areas. This study provided knowledge and conducted a comparative analysis of the effectiveness of two main methods for treating microbial contaminants in lake water: granular activated charcoal and silica gel. Furthermore, the experiment was subjected to before and after the application of activated carbon and silica gel. The pre-testing was conducted to identify the initial quantity of microbial contaminants. The preparation methods for bamboo into charcoal are initiated with the following steps: cutting, drying, loading, and sealing the drum kiln, heating, carbonization, cooling, and removing charcoal. Afterward, the bamboo charcoal underwent a chemical process to create activation using potassium hydroxide to generate a large surface area and enhance the adsorption capability. The two treatments were added to the lake water sample via filtration. Moreover, the post-testing involves performing serial dilution and microbial counts to determine the difference between before and after the contaminant's growth. Based on the results, the granular activated carbon is more effective than the silica gel because of its greater adsorption capacity resulting from its extensive pore spaces. This research study contributes significantly to researchers in the field and further advancements in utilizing granular activated carbon and silica gel to ensure clean and sustainable resources.

Food security is a global problem of humanity and the main factors affecting it

Food, its production, distribution and consumption are the most important elements of the world economic system. The significance of the food problem is determined primarily by the fact that in the structure of human needs, the need for food is of primary importance. In addition, the degree of her satisfaction is insufficient. The problem of food security is one of the most important global problems today. Rising food prices amid the global financial crisis have made food unaffordable for many families, especially in developing countries. The article analyzes various scientific approaches that explain the essence of the global food problem, the place of food security in the system of economic security of the state as its separate component. According to the processed materials of the FAO (Food and Agriculture Organization of the United Nations), modern views on food security as one of the global problems of mankind were systematized, the world state of food security was analyzed and the main factors affecting it were determined. It was established that the largest number of undernourished people live in Asia (55%), Africa (37%), Latin America and the Caribbean (8%). It was found that poverty is the main driver of food insecurity. Losses of food products at all stages of their promotion in the supply chain (production, transportation, storage and consumption), as well as FAO recommendations on ways to transform food systems to solve the global food problem and «ensure access to affordable and healthy food for all segments of the population in the countries of the world» are given in the context of achieving the goals of sustainable and inclusive development». The problem of food supply for Ukraine is briefly described. According to a preliminary estimate by the FAO, direct losses of assets in the field of agriculture as a result of the war in Ukraine amount to more than 6.5 billion US dollars. At present, the losses of available cultivated areas amount to more than 25% including more than 70% of irrigated lands, about 25% of berry crops and — 20% of gardens.

Reflections on Lithium-Ion Cells. Genesis of the Problem and Theoretical Introduction

Aim: This article presents an identification and analysis of the hazards associated with the operation of lithium-ion technology, the range of applications, an overview of hazardous incidents domestically and also internationally, the brief history of lithium-ion batteries, as well as recommendations on the use and storage of batteries published not only by domestic but also foreign fire and occupational safety organizations. Introduction: The increased mobility of people doing their work with computers has created the need to produce portable devices that require concentrating as much energy as possible in a limited enclosure volume. These devices accompany the user in everyday life, during travel and also in a variety of work. In order to meet these criteria, it was necessary to solve these problems, first of all, the problem of power supply, which would allow to use the electricity stored by them in a long-lasting but also very efficient way. However, modern solutions bring a number of new risks that are not obvious at first glance and require detailed analysis. Project and methods: Based on a critical analysis of the literature, the authors presented the advantages and disadvantages of cells used in smartphones, laptops, portable power tools used in households across the globe and even electric cars. The development of lithium-ion battery technology and the expansion of their range of applications makes it necessary to develop solutions to enhance safety during their use, together with procedures to prevent possible explosions and fires, allowing effective life and health protection of users, as well as safeguarding all property and the environment. Methodology: Opierając się na krytycznej analizie literatury, autorzy przedstawili zalety i wady ogniw wykorzystywanych w smartfonach, laptopach, przenośnych elektronarzędziach, a nawet samochodach elektrycznych. Rozwój technologii produkcji akumulatorów litowo-jonowych oraz rozszerzenie zakresu ich zastosowania sprawia, że konieczne jest opracowanie rozwiązań zwiększających bezpieczeństwo podczas ich użytkowania oraz procedur zapobiegania ewentualnym wybuchom i pożarom, pozwalających na skuteczną ochronę życia oraz zdrowia użytkowników, a także zabezpieczenie wszelkiego mienia i środowiska. Conclusions: In order to prevent fires spreading, it is necessary to understand the mechanisms that lead to ignition and possible explosions of cells and batteries. From the point of view of preventing such failures and fires, it is important to recognize the response of burning batteries to various types of fire extinguishing agents and preventive measures. Continued research in this area can contribute to the evolution of more sophisticated and advanced safety technologies and the development of regulatory standards that in the future will guarantee the effective control of lithium-ion battery fires directly linked to their storage, use at high quantities, and the correct storage of waste (in the form of damaged and depleted batteries). Keywords: lithium-ion batteries, fire hazard, environmental protection, environmental pollution, toxic products of combustion

Exhaled Anesthetic Xenon Regeneration by Gas Separation Using a Metal-Organic Framework with Sorbent-Sorbate Induced-Fit.

Noble gas xenon (Xe) is an excellent anesthetic gas, but its rarity, high cost and constrained production prohibits wide use in medicine. Here, we have developed a closed-circuit anesthetic Xe recovery and reusage process with highly effective CO2-specific adsorbent CUPMOF-5 that is promising to solve the anesthetic Xe supply problem. CUPMOF-5 possesses spacious cage cavities interconnected in four directions by confinement throat apertures of ~3.4 Å, which makes it an ideal molecular sieving of CO2 from Xe, O2, N2 with the benchmark selectivity and high uptake capacity of CO2. In situ single-crystal X-ray diffraction (SCXRD) and computational simulation solidly revealed the vital sieving role of the confined throat and the sorbent-sorbate induced-fit strengthening binding interaction to CO2. CUPMOF-5 can remove 5 % CO2 even from actual moist exhaled anesthetic gases, and achieves the highest Xe recovery rate (99.8 %) so far, as verified by breakthrough experiments. This endows CUPMOF-5 great potential for the on-line CO2 removal and Xe recovery from anesthetic closed-circuits.

Exhaled Anesthetic Xenon Regeneration by Gas Separation Using a Metal‐Organic Framework with Sorbent‐Sorbate Induced‐Fit

Noble gas xenon (Xe) is an excellent anesthetic gas, but its rarity, high cost and constrained production prohibits wide use in medicine. Here, we have developed a closed‐circuit anesthetic Xe recovery and reusage process with highly effective CO2‐specific adsorbent CUPMOF‐5 that is promising to solve the anesthetic Xe supply problem. CUPMOF‐5 possesses spacious cage cavities interconnected in four directions by confinement throat apertures of ~3.4 Å, which makes it an ideal molecular sieving of CO2 from Xe, O2, N2 with the benchmark selectivity and high uptake capacity of CO2. In‐situ single‐crystal X‐ray diffraction (SCXRD) and computational simulation solidly revealed the vital sieving role of the confined throat and the sorbent‐sorbate induced‐fit strengthening binding interaction to CO2. CUPMOF‐5 can remove 5% CO2 even from actual moist exhaled anesthetic gases, and achieves the highest Xe recovery rate (99.8%) so far, as verified by breakthrough experiments. This endows CUPMOF‐5 great potential for the on‐line CO2 removal and Xe recovery from anesthetic closed‐circuits.

Performance analysis and optimization of a novel S-CO2 closed-Brayton-cycle-based thermal management system for scramjets

The thermal management system (TMS) based on closed-Brayton-cycle is a solution to solve the problems of thermal protection and electricity supply for long-endurance hypersonic vehicles. A novel TMS is proposed in this paper, and the system performance is simulated and analyzed based on a zero-dimensional thermodynamic cycle model and a quasi-one-dimensional heat transfer model. The results indicate that the heat transfer coefficients of the post-mixing method are significantly higher. As the split ratio of the bottom sub-cycle increases, net power first increases to a maximum value and then gradually decreases, but the fuel flow rate for cooling is the opposite. Moreover, the increase in turbine inlet temperature has a positive effect on both fuel flow rate and net power. The optimization results show that the minimum fuel flow rate for cooling is 0.3313 kg/s and net power reaches 162.37 kW when keeps wall temperature under the limit. Furthermore, if the maximum fuel temperature is 723 K, the fuel mass flow rate will further decrease to 0.2907 kg/s. This research provides a potential solution for enhancing the performance of the thermal management system for hypersonic vehicles powered by scramjets.

Case study: Design and properties of acoustic energy harvester

Converting acoustic energy into electric energy can not only suppress environmental noise but also provide energy supply, which is a potential way to solve the bottleneck problem of energy supply in wireless sensor networks (WSNs). An acoustic energy harvester structure and circuit system combining Helmholtz resonance effect with piezoelectric effect are proposed in this article. The band gap characteristics of the designed acoustic energy harvester are analyzed by plane wave expansion (PWE) theory and experiment. The substrate of Helmholtz resonator is made from piezoelectric sheet, and the acoustic energy harvester structure is arranged periodically. When the incident noise frequency keeps coincidence with the resonant frequency, the conversion efficiency goes high up to 21.3%. The influence of series and parallel connection of piezoelectric elements on the acoustic to electric energy is observed. The AC-DC conversion circuit is designed with rectifier bridge, and the energy storage circuit is designed with supercapacitor. The power obtained from the acoustic to electric energy conversion system is 1523 mW. Application tests indicate that the noise suppresses, energy conversion, and energy storage can be realized at the same time by the proposed acoustic energy harvester system.

System model of risks and trees of alternative solutions for improving the logistics chain at a manufacturing enterprise

The subject of this article is the decision-making processes for improving the elements of the supply chain of a manufacturing enterprise under conditions of uncertainty and risks. The purpose of the research is to reduce the time and cost of in supply and distribution of products of manufacturing enterprises by considering possible risks through making rational management decisions. The article addresses the following tasks: examination of the characteristics of supply chain elements; investigation of the main problems of supply and distribution management and identification of ways to solve them; development of a systemic model of logistic risks for a manufacturing enterprise; and formation of decision trees for alternative decisions in strategic supply chain management at manufacturing enterprises. The methods applied include a systems approach, structural decomposition methods, a risk-oriented approach. The following results were obtained: features and problems of supply chain elements such as supply, production, storage, and distribution were examined and identified; main supply chain management tasks were investigated and solutions identified; problems in warehouse management were pinpointed; internal and external supply risks were identified; a systemic model of logistic risks for a manufacturing enterprise was formed, which main components are logistic problems, partial risks, their consequences, and possible management decisions to mitigate risks; decision trees were built for problems of raw material supply instability and transportation bottlenecks and delays; an alternative decision diagram was constructed for an illustrative example. Conclusions: To overcome the problem of raw material supply instability, it is recommended to develop diversification of supply sources, stock reservation, and the use of alternative transport routes. Building alternative decision trees in strategic management is an effective tool for making rational decisions by manufacturing enterprises in complex conditions of uncertainty and risks. They help to analyze alternatives and their consequences to choose a path to optimize the supply chain.

Isolation and Total Synthesis of PM170453, a New Cyclic Depsipeptide Isolated from Lyngbya sp.

In our continuing search for biologically active new chemical entities from marine organisms, we have isolated a new cyclic depsipeptide, PM170453 (1), from a cyanobacterium of the genus Lyngbya sp., collected in the Indo-Pacific Ocean. Structure elucidation of the isolated compound was determined by spectroscopic methods including MS, 1H, 13C and 2D-NMR. To solve the supply problem for 1 and progress pharmaceutical development, the total synthesis of 1 that involves a total of 20 chemical steps in a convergent process was carried out. Its in vitro cytotoxic activity against four human tumor cell lines, as well as the inhibition of the interaction between the programmed cell death protein 1 PD-1 and its ligand PD-L1 were also evaluated.

Is It Possible to Predict Systemic Adverse Effects in Subcutaneous Allergen Immunotherapy? Single-Center Experience

Introduction: Subcutaneous immunotherapy (SCIT) is the oldest and an efficient immunotherapy method that has been used for the treatment of allergic diseases. Systemic adverse effects (SAEs) may occur during the SCIT. For this reason, there may be problems in the continuing treatment. In this study, we primarily aimed to determine the frequency of SAEs, the risk factors that may be associated with SAEs, and clinical and laboratory parameters that can predict systemic reactions in the patients who underwent SCIT. Second, we aimed to evaluate the reasons for discontinuing SCIT and the conditions special to Turkey. Methods: The files of 295 patients who had received SCIT were evaluated retrospectively. Results: SCIT was administered against house dust mites (HDM) in almost all patients (n: 291, 98.6%). A total of 14,357 injections were administered to 295 patients included in the study, and 47.8% (n: 141) of the patients discontinued treatment. The most common reason for discontinuing treatment was the supply problem in Turkey for immunotherapy preparations (n: 70, 49.6%). The second reason was that the injection visits were not continued regularly, even though there were no adverse effects related to the treatment (n: 44, 31.2%). SAEs were observed in 16.6% of the patients and 0.66% of the injections. SAEs were more frequent in girls, in asthmatic patients, and in moderate asthmatic patients (p = 0.005, p = 0.016, p = 0.043, respectively). Treatment was terminated in 13 patients (4.4%) due to SAEs. The most common SAE was bronchoconstriction (n: 40, 85.1%). None of our patients developed hypotension or loss of consciousness. Median blood eosinophil count and basophil count and the skin prick test diameter for Dermatophagoides farinae were observed to be significantly higher in the group with SAE (p = 0.024, p = 0.034, p = 0.045, respectively). Conclusion: Although SAE may develop in pediatric patients undergoing HDM-specific SCIT, severe reactions are rare. Girls, asthmatic patients, especially moderate asthmatic patients, and patients with high blood eosinophil and basophil levels should be monitored more carefully for the development of SAE.

Application of GPR to Detect Lost Valve Chambers in a Utility Network

The exact geographic location of the fresh water transmission network of Dhaka WASA was not known to the agency. With time and development works, access to many such underground valve chambers were lost. Their recovery was usually done through manual digging and trenching. This was expensive, time- and labour-consuming, often led to traffic jams, and the rate of success was low. This study was conducted to use the non-intrusive method of Ground Penetrating Radar to locate those valves as an alternative. A total of 27 out of the 41 lost nodes in the network was successfully recovered and their precise location was recorded using RTK-GNSS. The article presents the detail procedure of locating the valve chambers of underground pipeline network. It also highlights how the lack of collaboration between agencies are causing water supply and maintenance problems to this day, and how infrastructure development of one agency may erode successes of another. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(2), 2023, P 139-151

Optimization of guide plates and orifice plates on thermal management of battery energy storage system

The performance, state of health and lifetime of the battery energy storage system (BESS) depend heavily on the temperature uniformity between batteries. The BESS is more prone to uneven temperature distribution due to the inclusion of more battery modules. Improving the air supply uniformity of each battery module is the key to ensure the temperature uniformity of the system. In order to solve the problem of uneven air supply in traditional duct, the present study proposes a composite duct structure with optimized L-type guide plates and orifice plates. Based on the orthogonal analysis method, the optimization of guide plate structures in the sub duct and the main duct is completed. Combined with power consumption analysis, the porosity of orifice plates in the ducts is determined. The results show that when guide plates and orifice plates are in the best design condition, compared with the initial scheme, the air supply uniformity coefficient of the BESS is reduced from 75.07 % to 6.29 %. The air supply uniformity of the system is increased by 91.62 %. The maximum temperature difference of the BESS is reduced from 17.36 K to 4.35 K. The temperature uniformity of the system is increased by 74.94 %. This study is helpful to the design and optimization of the duct for the thermal management system of BESS in the future.

Biofungicides Based on Plant Extracts: On the Road to Organic Farming.

Phytopathogenic fungi are responsible for diseases in commercially important crops and cause major supply problems in the global food chain. Plants were able to protect themselves from disease before humans played an active role in protecting plants. They are known to synthesize a variety of secondary metabolites (SMs), such as terpenes, alkaloids, and phenolic compounds, which can be extracted using conventional and unconventional techniques to formulate biofungicides; plant extracts have antifungal activity and various mechanisms of action against these organisms. In addition, they are considered non-phytotoxic and potentially effective in disease control. They are a sustainable and economically viable alternative for use in agriculture, which is why biofungicides are increasingly recognized as an attractive option to solve the problems caused by synthetic fungicides. Currently, organic farming continues to grow, highlighting the importance of developing environmentally friendly alternatives for crop production. This review provides a compilation of the literature on biosynthesis, mechanisms of action of secondary metabolites against phytopathogens, extraction techniques and formulation of biofungicides, biological activity of plant extracts on phytopathogenic fungi, regulation, advantages, disadvantages and an overview of the current use of biofungicides in agriculture.

Use of dairy industry side-stream lactose for tablet manufacturing − proof of concept study

During recent years there have been shortages of certain drugs due to problems in raw material supply. These are often related to active ingredients but could also affect excipients. Lactose is one of the most used excipients in tableting and comes in two anomeric and several solid-state forms. The aim of this study was to utilize lactose from a dairy side-stream and compare it against a commercial reference in direct compression. This would be a sustainable option and would secure domestic availability during crises. Two types of lactose, spray-dried and freeze-dried, were evaluated. Lactose was mixed with microcrystalline cellulose in different ratios together with lubricant and glidant, and flowability and tabletability of the formulations was characterized. The fully amorphous and small particle-sized spray-dried lactose flowed inadequately but exhibited good tabletability. The larger particle-sized, freeze-dried lactose exhibited sufficient flow and better tabletability than the commercial reference. However, disintegration and drug release were slower when using the investigational lactose formulations. This was most likely due to remaining milk proteins, especially caseins, in the lactose. Overall, the investigational lactose provides promise for the use of such a side-stream product during crisis situations but enhancing their properties and/or purity would be needed.

Approved and Commercialized Antidiabetic Medicines (Excluding Insulin) in Seven European Countries-A Cross-Sectional Comparison.

Diabetes mellitus is a complex, multifactorial, progressive condition with a variety of approved therapeutic options. The purpose of this study was to offer an overview of the authorized antidiabetic medicines (excluding insulin) compared with marketed products in seven European countries. Data were obtained from primary sources, including the websites of national authorities and directly from specialists in the countries of interest. The range of marketed medicines compared with the authorized group was assessed in terms of active pharmaceutical ingredients (>60% in Bulgaria, France, Serbia), brand names (>70% in Bulgaria, the Czech Republic, Romania, Serbia, Spain), pharmaceutical forms (>60% in all countries), strengths (>60% in Bulgaria, the Czech Republic, Romania, Serbia, Spain), marketing authorization holder (≥50% in all countries) and the status of medicine. Spain was found to have the highest number of products based on most of these attributes. Over 90% of authorized medicines had a pharmacy price in Serbia. Regarding the newer class of GLP-1 receptor agonists, a retail price for all approved substances was available in Bulgaria, Romania, Serbia, and Spain. Only one brand name with one concentration was found available for some agents, being susceptible to drug shortages: glibenclamide (Romania, Serbia, Spain), glipizide (the Czech Republic, Poland, Romania, Spain), glisentide (Spain), acarbose (the Czech Republic), sitagliptin (Bulgaria, Poland), vildagliptin (the Czech Republic, Poland) and saxagliptin (the Czech Republic, France, Romania, Serbia). An overview of the national and international therapeutic options may allow competent authorities and health professionals to take rapid measures in case of supply problems or health crises.

STUDY OF LONG-TERM WATER SUPPLY IN THE AREA OF MUNICIPALITY OF TEŠANJ, BOSNIA AND HERZEGOVINA

<p>This paper examines the issue of water supply in the municipality of Tešanj, which has been identified as crucial for many years due to the indispensable nature of water as a basic resource necessary for life. The available capacity of the Kraševo-Jelah-Tešanj central water supply system is 47 l/s. By calculating the daily water demand in the area, we determine a water deficit of 51.11 l/s, which needs to be addressed. The analysis and synthesis of data during the preparation of the study leads to the proposition of an artificial aquifer recharge system as a solution to the long-term water supply problem in the mentioned area.</p>

Tourism Sector Labor Supply During the Covid-19 Pandemic Recovery Period in Bali: Literature Review

One of the issues that emerged in tourism sector employment during the recovery period from the Covid-19 pandemic was the decline in the quality of human resources, namely related to the labor who previously worked in the tourism sector not all returning, causing a shortage of trained personnel in the midst of tourism recovering. This creates problems in labor supply that require resolution. Labor supply research has been used in various ways and has attracted the attention of academics and practitioners as well as governments because it has an important role in policy making. Method By understanding labor supply based on a literature review, strategies can be developed and implemented to solve the problem of labor supply in the tourism sector in an effort to create a new balance, namely that the Bali economy does not only rely on the tourism sector but also other potential sectors. This article also provides direction for future studies to solve tourism sector labor problems during the recovery period from the Covid-19 pandemic.

Life Cycle Sustainability Assessment of Waste to Energy Systems in the Developing World: A Review

The global move towards a circular economy, as well as that of achieving the United Nations Sustainable Development Goals (SDGs), has necessitated the search for several sustainable solutions in various sectors. Given this, the provision of sustainable waste management and electricity systems constitute a significant part of the SDGs, and the waste-to-energy (WtE) concept has recently become a key topic given that it can potentially help reduce the dependence on fossil fuels for energy generation, as well as minimizing the need to dispose of waste in landfill. However, to date, the sustainability assessments of WtE generation technologies have been limited in scope concerning the three-dimensional sustainability framework (economic, environmental, and social). Life Cycle Sustainability Assessment (LCSA) has been proposed as a potential approach that could comprehensively address these three pillars of sustainability simultaneously based on life cycle thinking. LCSA, as a holistic method, could also potentially deal with the complexity associated with decision-making by allowing for the consideration of a full range of possible sustainability consequences. LCSA is an analytical tool that integrates the Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and Social Life Cycle Assessment (sLCA) methodologies, which already exist and continue to be developed. Individually, these life-cycle approaches tend to be used to point out particular ‘hotspots’ in product or service systems, and hence focus on direct impacts in a given sustainability domain, neglecting the indirect ones. LCSA aims for a more holistic sustainability perspective and seeks to address the associated challenge of integrating these three pillars of sustainability into an overall and more comprehensive sustainability assessment. This need for harmonization within the LCSA methodology is a major challenge in its operationalization. In recent years there has been steady progress towards developing and applying LCSA, including for WtE. The aim of this paper is to review the most recent trends and perspectives in developing countries, especially regarding how LCSA could help inform decision-making. The paper also analyses the LCSA literature to set out the theoretical and practical challenges behind integrating the three methods (LCA, LCC, and sLCA). The review was conducted via a search of keywords such as LCSA, waste, and energy in the Web of Science databases, resulting in the selection of 187 publications written in English. Of those, 13 articles operationalized LCSA in specific waste and WtE related case studies. The review provides a review of the application of LCSA for researchers, technological experts, and policymakers through published findings and identifies perspectives on new research. These include uncertainty, subjectivity in weighting, double-counting, the low maturity of sLCA, and the integration of the interconnection between the three dimensions (environmental, economic, and social dimensions) of LCSA results in decision-making. In addition, gaps (such as the integration of the interconnection between the three dimensions) that need to be addressed via further research are highlighted to allow for a better understanding of methodological trade-offs that come from using the LCSA analytical approach to assess the sustainability of WtE generation technologies, especially in developing countries. It is hoped that this study will be a positive contribution to environmental and energy policy decisions in developing countries faced with the dual problems of waste management and electricity supply along with their sustainable development goals.

A new empirical correlation of MMP prediction for oil – impure CO2 systems

CO2 flooding is a widely-used technique for enhancing oil production, with miscible CO2 flooding exhibiting higher recovery potential compared to both immiscible and near-miscible CO2 flooding. However, the problem of insufficient CO2 supply is increasingly critical in many reservoirs. When faced with a shortage of gas supply, the key to the successful implementation of miscible CO2 flooding lies in accurately predicting the MMP of impure CO2. This study leverages MMP data derived from both experimental and simulation results, utilizing both linear and nonlinear regression methodologies to formulate empirical correlations for MMP prediction. In addition, ridge regression is used to solve collinearity problem.Compared with former investigations, the impure CO2 correlation proposed in this study integrates the ratio of the specific injection gas mole fraction to the crude oil mole fraction as novel independent variables. This inclusion reflects the actual interaction between the specific injection gas and crude oil during the miscibility process. Furthermore, the correlation can be linearized to the greatest extent through this way and such linearization illustrates the fundamental concepts more distinctly, offering a more practical and comprehensible approach. This formula combines the prediction of the minimum miscible pressure with the interaction mechanism of the miscible process, and the dominant factors in the miscible process can be determined. In terms of reducing the minimum miscible pressure, the interaction between C4 + C5 in the injected gas and C1 + N2 in the crude oil component is the strongest, while the interaction between N2 in the injected gas and C2-6 in the crude oil was most significant in increasing the minimum miscible pressure by comparison.The correlations presented for impure CO2 yield an average absolute deviation of 2.18 % and sustain a relative deviation within ± 10 %, surpassing previously published correlations. This study highlights the accuracy and effectiveness of the developed correlations for estimating MMP for impure CO2. The suggested MMP correlation offers a practical and efficient means of determining MMP for the implementation of impure CO2 miscible flooding in the field.