An equation of state for solid–liquid–vapor equilibrium applied to gas processing and natural gas liquefaction

Advanced natural gas liquefaction and regasification processes: Liquefied natural gas supply chain with cryogenic carbon capture and storage

A further evaluation of the clausius equation of state in thermodynamic property calculations

Evaluation of prediction models for the physical parameters in natural gas liquefaction processes

Natural gas, even more biogas, comply with this requirement but gas wells in the most areas are rather economically not accessible due to infrastructural or legislative requirements. The demands of small-scale module natural gas liquefaction plant have been gained considering attentions in recent years. In natural gas liquefaction plant, the core heat transfer equipment - efficient heat exchanger design and cold box systems integration technology promote the system design more compact and efficient. However, traditional plate-fin heat exchanger that be widely adopted as the core heat exchanger has strict purification standard definition, <50ppm for CO2 and <10ng/Nm3 for mercury, to prevent carbon dioxide (CO2) freezing and mercury corrosion inside aluminum material heat exchanger, which cause pretreatment system to large dimension and high cost. In this paper, a novel cold box with brazed plate heat exchangers (BPHE) for small-scale module LNG plant is proposed and designed. Firstly, the methane (CH4) /CO2 gas mixture cooling-down process are experimental conducted in a typical BPHE. The influences of carbon dioxide concentrations on solid precipitation from room temperature to liquid CH4 temperature are investigated, considering the flow resistance and heat transfer efficiency for natural gas liquefaction process. The maximum allowable carbon dioxide concentrations without clogging the flow channel of the plate heat exchanger and deteriorating the heat transfer efficiency under different pressures (2.5-5.5MPa) during the cooling process are obtained. Based on the research results, an optimized technology package of the cold-box has been designed and fabricated to achieve the practical application in a small-scale skid-mounted natural gas liquefaction process including cryogenic CO2 separation. First results and further optimization points will be discussed as well.

Simulation based Heuristics Approach for Plantwide Control of Propane Precooled Mixed Refrigerant in Natural Gas Liquefaction Process

Increasing the COP of a refrigeration cycle in natural gas liquefaction process using refrigerant blends of Propane-NH3, Propane-SO2 and Propane-CO2

Design optimization of single mixed refrigerant LNG process using a hybrid modified coordinate descent algorithm

Modeling natural gas-carbon dioxide system for solid-liquid-vapor phase behavior

Considering its clean and environmental characteristics, natural gas has gradually attracted attention from countries around the world. China’s coal-to-gas project has significantly increased the country’s demand for, and supply of, natural gas. Liquefied natural gas (LNG) has also been gradually promoted, owing to its advantages of easy storage and transportation. However, the natural gas liquefaction process includes multiple phases, and each phase generates substantial industrial pollutants, such as CO2, SO2, and NOx. Despite this, the resulting environmental impacts have not been quantitatively assessed. Therefore, based on the production process of a liquefaction plant in the Shanxi Province, China, in this study, the Life Cycle Assessment (LCA) model was used to analyze the pollutant discharge in the unit’s natural gas liquefaction production process. By collecting data on the production capacity and composition reports of the eight major LNG-producing provinces, such as Henan, Sichuan, Inner Mongolia, Shaanxi, Xinjiang, Shanxi, Ningxia, and Hebei, the total amount of pollutants discharged from the natural gas liquefaction process in China was estimated. Finally, the environmental impact of the natural gas liquefaction process was evaluated according to the results of the environmental impact of pollutants. Our study arrived at the following conclusions: (i) 93.60% of China’s natural gas liquefaction output is concentrated in eight provinces; (ii) in terms of the unit’s LNG production, the Global Warming Potential (GWP), Acidification Potential (AP), Eutrophication Potential (EP), Photochemical Ozone Creation Potential (POCP) and Dust Potential (DP) proportions of each province explained the gas composition of LNG production gas sources in each province; (iii) the environmental problems caused by natural gas liquefaction were different in each provinces. In addition, we suggested relevant policy recommendations. First, the formulation of LNG-related policies should consider environmental pollution produced during the liquefaction stage. Second, if the problem of pollutant discharge in the liquefaction of natural gas is properly solved, it will not only reduce environmental pollution, but also generate additional income. Third, different provinces should optimize production technology based on the different gas qualities.

Phase equilibria of carbon dioxide with phenol and diphenyl carbonate

Exergy and energy analysis of a hybrid natural Gas/Hydrogen liquefaction cycle combined with methanol production plant

Phase equilibria of carbon dioxide + 1-nonanol system at high pressures

Vapor–liquid phase equilibrium of carbon dioxide with mixed solvents of DMSO + ethanol and chloroform + methanol including near critical regions

The paper presents the results of studying a combination of new technological solutions in the processes of natural gas liquefaction and helium extraction. The most common and effective way to ensure cooling capacity in the natural gas liquefaction process is to use a cascade cycle on mixed refrigerant (MFC) as external cooling. The influence of introduction an absorption refrigeration unit on the technological process has been studied. To extract helium, the combined separation and rectification method is used. The purity of helium obtained is 50% (in moles). The running conditions of operation and the corresponding technical characteristics of the devices are presented and described. The curves of the resulting characteristics of heat exchangers indicate the correctness of the thermo hydraulic calculations performed. The relative value of energy costs for obtaining 1 kg of liquefied natural gas in a technological process using MFC is 0.265 kWh/kg of LNG. Introducing an absorption refrigeration unit into the cycle reduces the ratio presented to 0.1849 kWh/kg of LNG. In the process of extracting helium, using an absorption refrigeration unit gives the result of 0.951 and 132.9 kW/kmol of helium, respectively. When using an absorption refrigeration unit, the helium extraction rate and power consumption ratio are 0.951 and 132.9 kW/kmol of helium, respectively. Application of the exergic analysis methods to the processes under consideration shows that the greatest value of exergic losses relative to other devices is observed in compressors. A detailed economic analysis has been carried out. It shows that the cost of the product obtained in the normal MFC cycle and in the MFC cycle using an absorption refrigeration machine is $ 0.1939 and $ 0.2069 per kg of LNG, respectively.

Among Floating liquefied natural gas (FLNG) operations, natural gas liquefaction is the most energy intensive. Hence, to achieve energy-efficient and eco-friendly FLNG operations that can meet offshore environment requirements, a hydrofluoroolefin-based single mixed refrigerant (SMR) natural gas (NG) liquefaction process is proposed. The proposed process is optimized using a sine cosine paradigm to reduce the overall energy consumption. Then, the economic performance of the proposed process is performed and analyzed against that of the conventional LNG process. Finally, uncertainty quantification is performed to analyze the process outputs under the effects of uncertain key decision variables to guarantee operational reliability. The optimization yields an energy consumption of 0.2317 kW, resulting in a 41.73% energy saving compared to the conventional SMR process. Moreover, the total annualized cost is reduced to 26.02% owing to the appropriate mixed refrigerant selection and process design. The results of the uncertainty quantification analysis indicate that the flow rates of methane and butane, the evaporation pressure, and the condensation pressure are the most influential factors when processing energy consumption and utilizing the minimum internal temperature approach. This study highlights the importance of introducing eco-friendly refrigerants to replace conventional refrigerants used in NG liquefaction processes.