Comparison of two schemes for district cooling system utilizing cold energy of liquefied natural gas

Two schemes（scheme Ⅰ and scheme Ⅱ）for designing a district cooling system（DCS）utilizing cold energy of liquefied natural gas（LNG）are presented.In scheme Ⅰ,LNG cold energy is used to produce ice,and then ice is transported to the central cooling plant of the DCS.In scheme Ⅱ,return water from the DCS is directly chilled by LNG cold energy,and the chilled water is then sent back to the central plant.The heat transportation loss is the main negative impact in the DCS and is emphatically analyzed when evaluating the efficiency of each scheme.The results show that the DCS utilizing LNG cold energy is feasible and valuable.The cooling supply distance of scheme Ⅱ is limited within 13 km while scheme Ⅰ has no distance limit.When the distance is between 6 and 13 km,scheme Ⅱ is more practical and effective.Contrarily,scheme Ⅰ has a better economic performance when the distance is shorter than 6 km or longer than 13 km.

A Novel Process for Natural Gas Liquids Recovery from Oil Field Associated Gas with Liquefied Natural Gas Cryogenic Energy Utilization

A novel process to recovery natural gas liquids from oil field associated gas with liquefied natural gas (LNG)cryogenic energy utilization is proposed.Compared to the current electric refrigeration process,the proposed process uses the cryogenic energy of LNG and saves 62.6%of electricity.The proposed process recovers ethane, liquid petroleum gas(propane and butane)and heavier hydrocarbons,with total recovery rate of natural gas liquids up to 96.8%.In this paper,exergy analysis and the energy utilization diagram method(EUD)are used to assess the new process and identify the key operation units with large exergy loss.The results show that exergy efficiency of the new process is 44.3%.Compared to the electric refrigeration process,exergy efficiency of the new process is improved by 16%.The proposed process has been applied and implemented in a conceptual design scheme of the cryogenic energy utilization for a 300 million tons/yr LNG receiving terminal in a northern Chinese harbor.

A power plant for integrated waste energy recovery from liquid air energy storage and liquefied natural gas

Liquefied natural gas(LNG)is regarded as one of the cleanest fossil fuel and has experienced significant developments in recent years.The liquefaction process of natural gas is energy-intensive,while the regasification of LNG gives out a huge amount of waste energy since plenty of high grade cold energy(-160℃)from LNG is released to sea water directly in most cases,and also sometimes LNG is burned for regasification.On the other hand,liquid air energy storage(LAES)is an emerging energy storage technology for applications such as peak load shifting of power grids,which generates 30%-40%of compression heat(-200℃).Such heat could lead to energy waste if not recovered and used.The recovery of the compression heat is technically feasible but requires additional capital investment,which may not always be economically attractive.Therefore,we propose a power plant for recovering the waste cryogenic energy from LNG regasification and compression heat from the LAES.The challenge for such a power plant is the wide working temperature range between the low-temperature exergy source(-160℃)and heat source(-200℃).Nitrogen and argon are proposed as the working fluids to address the challenge.Thermodynamic analyses are carried out and the results show that the power plant could achieve a thermal efficiency of 27%and 19%and an exergy efficiency of 40%and 28%for nitrogen and argon,respectively.Here,with the nitrogen as working fluid undergoes a complete Brayton Cycle,while the argon based power plant goes through a combined Brayton and Rankine Cycle.Besides,the economic analysis shows that the payback period of this proposed system is only 2.2 years,utilizing the excess heat from a 5 MW/40 MWh LAES system.The findings suggest that the waste energy based power plant could be co-located with the LNG terminal and LAES plant,providing additional power output and reducing energy waste.

The Model of Thermal Response of Liquefied Petroleum Gas Tanks Partially Exposed to Jet Fire

This paper describes a mathematical model developed to study the behavior of liquefied petroleum gas (LPG) tanks when subjected to jet fire. The model consists of a number of field and zone sub-models which are used to simulate the various physical phenomena taking place during the tank engulfment period. The model can be used to predict the pressure and temperature of the LPG in the tank, the temperature of the wall of tank, and the time of tank explosion. The comparisons between the model predicted results and the test data show good agreement. The results show that the jet fire partially impinging on tank wall led to higher wall temperature and the time to failure was shorter than that in engulfing pool fire. And the exposure of the upper wall in the vapor zone to the fire is more dangerous than that of the LPG contacted wall.

Thermodynamic design of a cascade refrigeration system of liquefied natural gas by applying mixed integer non-linear programming

Liquefied natural gas(LNG) is the most economical way of transporting natural gas(NG) over long distances. Liquefaction of NG using vapor compression refrigeration system requires high operating and capital cost. Due to lack of systematic design methods for multistage refrigeration cycles, conventional approaches to determine optimal cycle are largely trial-and-error. In this paper a novel mixed integer non-linear programming(MINLP)model is introduced to select optimal synthesis of refrigeration systems to reduce both operating and capital costs of an LNG plant. Better conceptual understanding of design improvement is illustrated on composite curve(CC) and exergetic grand composite curve(EGCC) of pinch analysis diagrams. In this method a superstructure representation of complex refrigeration system is developed to select and optimize key decision variables in refrigeration cycles(i.e. partition temperature, compression configuration, refrigeration features, refrigerant flow rate and economic trade-off). Based on this method a program(LNG-Pro) is developed which integrates VBA,Refprop and Excel MINLP Solver to automate the methodology. Design procedure is applied on a sample LNG plant to illustrate advantages of using this method which shows a 3.3% reduction in total shaft work consumption.

Effect of Tourmaline Modified with La-Doped Nano-CeO_2 on Consumption of Liquefied Petroleum Gas

Tourmaline was modified with cerous nitrate and lanthanum nitrate by coprecipitation method. Through characterization by differential thermal analysis, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy, it was found that the tourmaline modified with La-doped nano-CeOhad a better far infrared emitting property than the tourmaline modified with CeO2, which depended on La enhancing the redox properties of CeO, leaded to much more oxidation of Fe2+ to Fe3+ in the tourmaline. Based on the results of the water boiling test, it was found that the tourmaline modified with La-doped nano-CeOcould decrease the consumption of liquefied petroleum gas, which resulted from the tourmaline modified with La-doped nano-CeOdecreasing the molecular clusters volume of liquefied petroleum gas and combustion-supporting air.

Flow characteristics by particle image velocimetry in liquefied natural gas vaporizer model with several baffles

Shell-and-tube vaporizers are the most commonly used and dominated types of vaporizers in liquefied natural gas （LNG） realm. Due to efficient performance, shell-side flow in this type of vaporizers has received considerable attention and has been investigated extensively. However, the detailed flow structure in the shell needs to be determined for reliable and effective design. Therefore, the objective of this study was to clarify the flow structure in shell by particle image velocimetry （PIV）. Experiments were conducted using two types of model; 15% baffle cut having inlet and outlet positions !n the direction of 90° to the cut and 30% baffle cut having inlet and outlet positions in the direction of 180° to the cut. Each test section is 169 mm in inner diameter and 344.6 mm in length. The flow features were characterized in different baffle cuts with regards to the velocity vector field and velocity distribution. The results show that the flow characteristics of 15% baffle cut type vaporizer are comparable to those of 30% baffle cut type vaporizer.

Distribution and Chain Pattern of Liquefied Natural Gas Industry in China

The production and consumption of natural gas in China has been developing rapidly in recent years.It is expected that the annual growth rate of the demand for natural gas will reach 12% in the next 15 years,and the gas consumption in the primary energy will increase from 0.3% to 10% or more by 2020.However,since the supply of natural gas cannot satisfy the requirements,China has begun to build liquefied natural gas(LNG)terminals in the coastal regions such as Guangdong and Fujian,and solve this problem by importing LNG from foreign countries.LNG needs to be transported by LNG ships from abroad.With the rapid growth of global gas production,the volume of LNG trade also increases,and the interregional production increased from 0.3% in 1970 to 26.2% in 2004.So,we need LNG ships more than before.This article puts forward the distribution of LNG ships and the speculation of the future of LNG transportation based on the studies on foreign LNG production,the LNG trade,the building of LNG ships,the LNG transportation,the chain model of LNG distribution,etc.

Estimation on Global Reaction Heat for the Aromatization Process of Liquefied Petroleum Gas

The reaction heat effect analysis for the aromatization process of Liquefied Petroleum Gas (LPG) was completed in this paper. In order to characterize this complex reaction system, one set of independent reactions was determined by means of atomic coefficient matrix method. Based on reaction thermodynamic and stoichiometric knowledge, the heat effect, Gibbs free energy change and equilibrium constant for each independent reaction was calculated for the specified conditions. Under these conditions, based on the initial and final composition data from LPG aromatization experiments, the actual extent of reaction for each independent reaction was determined. Furthermore, the global reaction heat and adiabatic temperature rise of LPG aromatization reaction system could be estimated. This work would provide a theoretical guidance for the design and scale-up of reactor for LPG aromatization process, as well as for the selection of proper operating conditions.

One-step solvothermal synthesis of indium oxide as liquefied petroleum gas sensor

A liquefied petroleum gas （LPG） sensor with high selectivity, sensitivity and low power consumption has been developed based on indium oxide with very low resistance. Nanocrystalline In203 gas sensing materials were directly synthesized through a one-step controllable solvothermal process at 210 ℃ for 24 h, using InCI3.4H2O as the starting material, cetyltrimethyl ammonium bromide （CTAB） as additive and ethanol as the solvent. The obtained samples were characterized by X-ray diffraction （XRD）, and transmission electron microscopy （TEM）. The results showed that indium oxide takes on uniform cubic shape with range size of 10~30 nm and fine dispersivity. Gas sensitivity was measured in a mixing static gas. The results indicated that 3.0 V is the best working voltage of the sensor to LPG. Sensitivity is 12.6. The response-time and recovery-time are 3 s and 10 s respectively. Power consumption is only around 200 mW.

Temperature distribution and control in liquefied petroleum gas fluidized beds

Temperature distribution and control have been investigated in a liquefiedpetroleum gas (LPG) fluidized bed with hollow corundum spheres (A1_2O_3) of 0.867-1.212 mm indiameter at moderately high temperatures (800-1100℃). Experiments were carried out for the airconsumption coefficient α in the range of 0.3 to 1.0 and the fluidization number N in the range of1.3 to 3.0. Particle properties, initial bed height, α and N all affect temperature distribution inthe bed. Bed temperature can be adjusted about 200℃ by combined the adjusting of α and N.

Full-Scale Measurement and Numerical Analysis of Liquefied Petroleum Gas Water Heaters with Ventilation Factors in Balcony

This study carried out full-scale gas water heater combustion experiments and adopted FDS （fire dynamics simulator） to simulate three scenarios--different balcony environments when using water heater, such as airtight balcony, indoor door with openings and force ventilation to compare with full-scale combustion experiments. According to FDS simulation results, 02, CO and CO2 simulation concentration value correspond with full-scale experimental results. When the indoor O2 concentration was lower than 15%, which causes incomplete combustion, the CO concentration would rise rapidly and even reached above 1,500 ppm, causing death in short time. In addition, when the force ventilation model supplied the water heater with enough air to bum, the indoor CO concentration will keep low and harmless to humans. The study also adopted diverse variables, such as the opening area of window, outdoor wind speed and water heater types, to analyze deeply user＇s safety regarding gas water heater. In a result, while balcony area is larger than 14 mE, the volume of water heater is below 16 L （33.1 kW）, and the indoor window, connecting balcony with room, is closed, if the opening on the outdoor window of the balcony is larger than 0.2 mE, this can ensure the personal security of the indoor space.

Socio-Economic Implication of Nigeria Liquefied Natural Gas (NLNG) Project in Bonny Local Government Area, Rivers State, Nigeria

Notably, the Nigeria Liquefied Natural Gas (NLNG) project is the pioneer Liquefied Natural Gas (LNG) plant in Nigeria, aimed at both the diversification of the petroleum industry and utilization of the vastly flared natural gas resources of the nation. However, large scale energy projects have been known to generate both positive and/or negative impacts. Environmental Management Plans (EMP) have often been the compendium of information on approved mitigations, which normally include activities that could maximize the benefits of the host communities, and it’s not unusual for the Community Development and Corporate Social Responsibility (CDCSR) department of such an organization to be saddled with these contributions. But the activities of Nigeria LNG Ltd.’s CSR department have often been the source of criticism, as well as aspiration for improvement by host communities and other stake holders. This article thus aims to present a comprehensive compendium of NLNG’s CDCSR activities, up to the year 2010, and also highlight the level of satisfaction of the immediate and distant host communities against the level of performance of other donors in the area. Also the arrays of negative socio-economic consequences of the Nigeria LNG Ltd.’s activities were identified based on community perception. The results generally showed that comparatively, NLNG project has made more innovative positive socio-economic and health contributions to its areas of operation than the three tiers of government and other donors (including SPDC and Mobil Producing Nigeria). Surprisingly, agitations against Nigeria LNG Ltd.’s activities have not overshadowed its community development provisions, which have been of major assistance in several communities. There is however a dire need to review several aspects of Nigeria LNG Ltd.’s CDCSR activities, especially in the fulfilment of documented promises, as well as in project conception and community participation, for better completed projects acceptance by indigenous host communities. Conflict management strategies also need to be improved, while the dissatisfaction over benefits in New Finima needs to be urgently addressed.

Explosion Hazard Analysis of Liquefied Petroleum Gas Transportation

This paper presents a quantitative risk analysis of liquefied petroleum gas(LPG)transportation.An accident that happened on June 13,2020,on the highway near Wenling,China is studied as a case.In this accident,LPG carried by a tank truck on the highway leaked and caused a large explosion,which led to 20 deaths.Different methods are combined to calculate the consequence of the accident.Multi-energy model and rupture of vessel model are employed to calculate the overpressure;the simulation result of the multi-energy model is closer to the damage caused by the accident.The safety distances in accidents of LPG transport storage tanks of different capacities are calculated in this study;the results show that the damage of explosion will increase with the filling degree of the tank.Even though the filling degree is 90%(value required by law),the 99%fatality rate range will reach 42 m,which is higher than regulated distance between road and building.The social risk of the tank truck has also been calculated and the results show that the risk is not acceptable.The calculating method used in this study could evaluate the risk of LPG tanker more accurately,which may contribute to the establishment of transportation regulation so that losses from similar accidents in the future could be reduced.

Research on the navigational risk of liquefied natural gas carriers in an inland river based on entropy:A cloud evaluation model

Due to the flammability and explosive nature of liquefied natural gas(LNG),an extremely strict process is followed for the transporta-tion of LNG carriers in China.Particularly,no LNG carriers are operating in inland rivers within the country.Therefore,to ensure the future navigation safety of LNG carriers entering the Yangtze River,the risk sources of LNG carriers’navigation safety must be identi-fied and evaluated.Based on the Delphi and expert experience method,this paper analyses and discusses the navigation risk factors of LNG carriers in the lower reaches of the Yangtze River from four aspects(human,ship,environment and management),identifies 12 risk indicators affecting the navigation of LNG carriers and establishes a risk evaluation index system.Further,an entropy weight fuzzy model is utilized to reduce the influence of subjective judgement on the index weight as well as to conduct a segmented and overall evaluation of LNG navigation risks in the Baimaosha Channel.Finally,the cloud model is applied to validate the consistent feasibility of the entropy weight fuzzy model.The research results indicate that the method provides effective technical support for further study on the navigation security of LNG carriers in inland rivers.

大型LNG船用惰气发生器系统特点及其应用

为提高液化天然气(Liquefied Natural Gas,LNG)船与惰气发生器系统的匹配度,基于惰气制取流程,对不同类型惰气发生器的应用范围进行归纳,对大型LNG船用惰气发生器的系统特点、要求和布置准则进行分析,并对不同厂商惰气发生器的结构形式和性能特点进行对比。研究表明:惰气发生器的油耗、整机功率、排量等参数为大型LNG船选型的首要依据。研究成果可为大型LNG船用惰气发生器的选型与应用提供一定参考。

大型LNG船再液化设备基座静刚度分析及结构优化

为了保证大型液化天然气(Liquefied Natural Gas, LNG)船再液化设备的基座在设备工作载荷作用下具有较高的抵抗变形能力,提高再液化设备运转过程中的安全性,以大型LNG船用再液化设备的基座所受载荷为基础,进行整个再液化设备的基座结构设计,并基于有限元分析软件进行刚度计算。计算结果表明:在工作载荷作用下,基座抵抗横向和纵向变形的能力较弱,在结构优化加强时,增加结构的板厚对整个基座的静刚度改善作用亚于增加纵向或横向支撑型材。研究结果可为船舶类设备基座结构的设计及加强优化提供一定参考。

货物围护系统专用材料和预制件认证流程分析

为了明确液化天然气(Liquefied Natural Gas, LNG)船货物围护系统专用材料和预制件的认证流程,对认证过程进行总结,绘制成流程图,并对GTT公司在认证过程中的技术要求、评估和质量控制等内容进行分析。研究成果可为国内有较强技术能力且有认证需求的供应商提供一定参考。

LNG动力船舶修理安全管控

为了提升液化天然气(Liquefied Natural Gas, LNG)动力船舶修理期间的风险管控水平,对LNG燃料的基本特性展开介绍,分析LNG泄漏或失控所造成的危害,并对不同的LNG动力船舶系统的相应维修情况进行对比分析,同时阐述LNG动力船舶维修时存在的主要额外风险及相应风险产生的原因。在此基础上,提出船舶携带LNG修理期间在危险区域和安全敏感区域工作的相应预防措施。研究成果可为LNG动力船舶修理安全管控提供一定参考。

Effect of Ca promoter on LPG synthesis from syngas over hybrid catalyst

Direct synthesis of liquefied petroleum gas （LPG） from syngas was carried out over hybrid catalyst consisting of methanol synthesis catalyst and modified Y zeolite with Pd and Ca by different methods. The decrease of CO conversion was mostly attributable to the sintering of Cu in methanol synthesis catalyst. On the other hand, coke deposition on Y zeolite was the reason for the decrease of LPG selectivity. The introduction of Ca decreased the strong acid sites of Y zeolite, suppressed coke formation, and thus improved the stability of hybrid catalyst.