Liquefied Petroleum Gas Production Research Articles

Assessment of a Full-Electric Floating Liquefied Natural Gas Concept for Harsh Sea State Conditions at Remote Ultra-Deepwater Locations

_ This work describes an offshore gas monetization solution for harsh environmental conditions at ultra-deepwater and remote locations, as an alternative to conventional onshore plants associated with long subsea pipelines for Greenfield projects. Although gas-to-liquids and marine compressed natural gas are initially evaluated, associated gas is supposed to be exported from deepwater floating production storage and offloading units to a central floating liquefied natural gas (FLNG) facility for additional treatment, fractionation, and liquefaction, producing liquefied natural gas (LNG) and liquefied petroleum gas (LPG) for further tandem offloading. To demonstrate the technical feasibility of the proposed FLNG, its key technologies are reviewed, including liquefaction process selection, cargo containment system, station-keeping, offloading, and power generation. A full-electric FLNG is proposed, replacing conventional feed gas power generation systems with inner hull nuclear power modules, envisaging neutral CO2 emissions and earlier first LNG drop milestone achievement. The FLNG general arrangement is developed, along with its internal cargo tanks layout, for preliminary LNG and LPG production rundown and feed gas throughput. Numerical analyses are carried out to show that static and dynamic tilt criteria can be met, even for harsh sea states. Gas import riser configurations for the challenging ultra-deepwater location are outlined, after appropriate FLNG station-keeping analyses, in addition to a feasibility assessment of seawater intake risers, aiming for an overall gas plant efficiency increase. Keywords FLNG; FPSO; LNG/LPG; associated gas; design (general)

Enhancing liquefied petroleum gas production through debutanizer column optimization

Debutanizer columns are important in natural gas processing as they are crucial in generating Liquefied Petroleum Gas (LPG). LPG is well recognised for its environmentally benign combustion properties, making it a desirable fuel option for cooking, heating, and transportation. The optimisation of debutanizer units has significant relevance in improving the efficiency of LPG separation. This study aims to enhance the separation efficiency of a butane removal tower by modelling and optimising its operation using HYSYS software. The research aims to introduce innovation in this field. A series of comprehensive simulations were carried out to achieve this goal, resulting in outcomes that nearly corresponded to the findings obtained from natural gas units. Moreover, a thorough examination was conducted to examine the impact of temperature, pressure, feed flow rate, and reflux ratio on the production yield of n-butane. The study reached this conclusion by optimising tower conditions, with a particular emphasis on improving the performance of the condenser during the hot summer season. In ideal circumstances, the distillate demonstrated a butane concentration ranging from 70% to 74%, while all overhead gas is condensed in all instances. This study highlights the importance of optimising the debutanizer column in enhancing the quality and efficiency of LPG production in the natural gas processing sector.

Life Cycle CO2 Emissions Analysis of a High-Tech Greenhouse Horticulture Utilizing Wood Chips for Heating in Japan

High-tech greenhouse horticulture offers efficient crop cultivation that is unaffected by outdoor climate. However, compared to conventional cultivation systems, energy requirements, such as greenhouse heating and control, are larger, and concerns about the associated increase in CO2 emissions exist. Although several previous studies have analyzed CO2 emissions from high-tech greenhouse horticulture, few have covered the entire life cycle. This study aimed to analyze CO2 emissions from high-tech greenhouse horticulture for tomatoes in Japan across the entire life cycle. A hybrid method combining process and input–output analyses was used to estimate life cycle CO2 (LC-CO2) emissions. The emission reduction potential of replacing liquefied petroleum gas (LPG) for greenhouse heating with wood chips was also examined. The results show that LC-CO2 emissions were estimated to be 3.67 kg-CO2 per 1 kg of tomato, 55.6% of which came from the production and combustion of LPG for greenhouse heating. The substitution of LPG with wood chips has the potential to reduce LC-CO2 emissions by up to 49.1%. However, the improved LC-CO2 emissions are still higher than those of conventional cultivation systems; thus, implementing additional measures to reduce LC-CO2 emissions is crucial.

A Techno-Economic Analysis of Natural Gas Valuation in the Amazon Region to Increase the Liquefied Petroleum Gas (LPG) Production in Ecuador

Liquefied petroleum gas (LPG) is a C3/C4’s hydrocarbon mixture used as fuel gas, obtained through natural gas processing or crude oil refining. The Ecuadorian LPG production (~1.88 MMbbl/year) comes from the Shushufindi gas plant and the Esmeraldas refinery. However, LPG production cannot meet the Ecuadorian market demand, and over 90% of this commodity is imported. At the same time, the natural gas produced in the Amazon region is not fully valued. A significant quantity of the associated gas is flared (~100 MMscfd), representing wasted energy with a significant environmental impact. Therefore, this study aimed to develop a technical and economic assessment of the potential natural gas valuation in the Amazon region to increase LPG production. The study started with a detailed review of the associated gas produced in the Amazon region. The data were analyzed considering the geographic location of the hydrocarbon fields, molar composition, flowrates, and operational conditions. Then, a natural gas value chain visualization was proposed and technically analyzed. Finally, an economic feasibility (class V) study was conducted, considering a preliminary analysis of capital expenditure (CAPEX) and an economic balance. The outcome of this study showed that by processing 21.50 MMscfd of associated gas from the Sacha field, domestic LPG production could increase by 30.9%. The required infrastructure consists of conventional processes for natural gas processing, with an estimated CAPEX of 36.6 MMUSD. Furthermore, despite the domestic subsidies of commodities, the potential savings for the country would be 32.13 MMUSD/year, an alternative more economically viable than the current LPG imports. Thus, the investment cost will be justified.

Minimising Butadiene Level in Liquefied Petroleum Gas (LPG) via Non-Stirred Blending with Numerical Approach

LPG has variable commercial grades due to its varying LPG composition will yield different properties. Because their properties depend on the composition, the LPG quality will differ based on the source of its production extracted either from refinery streams or natural gas. The composition of propane and butane, which are the two major components in LPG composition, play an important role in reflecting the properties of LPG, as the mixtures influence the boiling points and also meet product specification requirements. Butadiene is also present in LPG, albeit in trace amounts. Although butadiene is a minor component, it must be kept minimised of the total weight fraction due to regulatory limits. Butadiene is a hazardous chemical that, when inhaled, can cause cancer and genetic defects. LPG used for commercial purposes that contain of any carcinogenic substance such as butadiene must also be classified as carcinogenic. The LPG plant operator is facing the problem that imported LPG composition from outside sources contain levels of butadiene that exceed the regulatory limit of 0.5% of weight fraction. LPG composition, containing butadiene levels that exceed 0.5% of weight fraction is considered as off-specification, while butadiene levels less than 0.5% of weight fraction are considered as on-specification the LPG products. To reduce the levels of butadiene that exceed 0.5% of the weight fraction in off-specification LPG products, the blending of on-specification LPG products with off-specification was introduced and provided the most economical method inside the plant. The jet mixing approach was selected to predict the homogeneous blending time for each different off-specification LPG composition because it is the best approximation for natural mixing behaviour. Four empirical mixing time correlations of jet mixing were applied for the prediction of homogeneous blending time; the correlations were derived by Lane and Rice (1982), Maruyama, Ban and Mizushina (1982), Grenville and Tilton (1997) and Hiby and Modigell (1978). The homogeneous blending time predicted by these four mixing time correlations decreased as the quantity of on-specification LPG required increased, which is in good agreement with both simulation results of 95% and 99% mixing. Therefore, due to the development of individual jet mixer correlation, these four mixing time correlation results in different homogeneous blending times was going through the different measurement techniques and monitoring methods in jet mixed tanks.

Urban residential energy switching in China between 1980 and 2014 prevents 2.2 million premature deaths

Urban residential energy switching in China between 1980 and 2014 prevents 2.2 million premature deaths

Increasing LPG production by adding volatile hydrocarbons to reduce import gap in Egypt

Liquefied petroleum gas (LPG) becomes popular in the twentieth century as source of energy, since it is economically feasible to be produced, transported, sold and stored as a liquid fuel. LPG in Egypt is considered one of the most important domestic fuels. Egypt imports half of its LPG fuel demand. Many researches have been developed to increase the production of LPG in Egypt by increasing the productivity of the refineries. The objective of this study is to investigate the possibility of adding other relatively volatile hydrocarbons as ethane, n-pentane and pentanes’ isomers (iso-pentane and neo-pentane) and/or utilizing relatively volatile oxi-hydrocarbons [mainly dimethyl ether (DME) or dimethyl propane (DMP)] to increase LPG production without affecting its specifications, in order to reduce the import gap of LPG in Egypt. The new LPG mixture is adjusted to meet the Egyptian specifications of LPG (2020). Due to ethane critical properties, it is recommended not to add ethane to LPG since the behavior of ethane cannot be predicted at 50 °C and will be separated inside the LPG bottle. In addition, it will necessitate the increase in LPG butane content. In summer, it is recommended to add i-C5 or 2,2DMP or a mixture of both to LPG (depending on the cost). In winter, it is recommended to add 2,2DMP or a mixture of 2,2DMP with i-C5 to LPG (depending on the cost). Adding DME to LPG with any percentage will decrease the heating value below the Egyptian heating value specifications (2020). Adding neo-pentane to LPG is more preferable than DME, since the heating value of neo-pentane is higher than that of DME. Also, the production cost of the neo-pentane is lower than that of DME.

Technology Focus: Natural Gas Processing and Handling (April 2020)

Technology Focus In 2019, the US experienced the lowest natural gas prices since 2016. This was despite natural gas consumption increasing in the residential and commercial sector by 2% (between October and December) according to the US Energy Information Administration (EIA). In July and August, the electric generation sector also experienced an increase in natural gas consumption because of above-average humidity levels in the Midwest and Northeast. Natural gas inventories at the end of March recorded the lowest levels since 2014 during withdrawal season, whereas the injection season recorded the second-highest levels from sustained growth in natural gas production. This trend of low gas prices was because of natural gas production growth, as prices continued to decline through the rest of 2019. The EIA forecasts an increase in natural gas consumption by 1.4 Bcf/D (1.7%) in 2020. The average US natural gas price is projected to fall by 9% to $2.33/million British thermal units (MMBtu) in 2020. The EIA said it expects continued growth in natural gas production in 2020 in response to improved drilling, increased associated gas production, and increased Appalachian and Permian pipeline take-away capacity. As of 3 February, Henry Hub spot price closed at $1.82/MMBtu, $0.87 lower than the same time last year. Weather temperatures were warmer than expected, except in the Northeast and Midwest where it was colder than expected, hence affecting winter demand. Globally, the Paris-based International Energy Agency’s 5-year forecast shows natural gas demand driven by Asia-Pacific growth, with the region accounting for approximately 60% of the total gas consumption forecasted increase through 2024. China is expected to be at the forefront of this demand growth because it is expected to constitute approximately 40% of the total gas demand increase through 2024. The global liquefied petroleum gas (LPG) market has continued to grow reasonably in the past decade, and the US, as a result of its strong domestic LPG production, has ascended in recent years as the largest LPG producer and exporter in the world. The Asia-Pacific region, because of its growing population, constitutes the highest market share of the global LPG consumption. The global LPG market trend is predominantly supply-driven by natural gas and crude oil but not so much from refining. According to IHS Markit, LPG demand in Asia-Pacific grew approximately 3.5% in 2018 and has continued to maintain its steady growth in 2019. Global supplies of LPG are expected to rise approximately 5% to 325 million tonnes in 2020. By region, approximately 28% of the global supplies will be from the US and approximately 20% from the Middle East. Asia-Pacific will continue to be the main driver for LPG demand growth, accounting for approximately 45% (4.6 million B/D) of the global demand. The prominent increase in US LPG exports has resulted in significant changes in the LPG global trade flow patterns in recent years, demonstrating a shift from a dependency on exports from the Middle East. More can be learned by attending the SPE Annual Technical Conference and Exhibition in Denver on 5–7 October and the SPE Asia Pacific Oil and Gas Conference and Exhibition in Perth, Australia, on 8–11 September. Recommended additional reading at OnePetro: www.onepetro.org. SPE 195759 Solutions for Seal Gas Leakage Recovery in Methane Compression: Integration Into Processing Lines or Gas Valorization Systems by Filippo Conforti, Baker Hughes, et al. SPE 197582 Running Sour Hydrocarbon Assets: Eni’s Story of Experience by Luciano Scataglini, Eni, et al. SPE 195555 Experimental Investigation of Integrity Issues of Underground Gas Storage Containing Hydrogen by Erik Clemens Boersheim, Clausthal University of Technology, et al.

Exergetic analysis of an LPG production plant using HYSYS software

This work is a contribution on thermo-economic analysis of a Liquefied Petroleum Gas (LPG) unit production which is simulated in Aspen HYSYS. The fractional unit of the plant will be studied in order to locate exergy destruction area in the system. The fractional unit contains mainly three sections: heat recovery, rectification columns and cooling section. Also we will determine the exergy for all streams, which will be useful for the thermo-economic analysis. As a result, two thirds of exergy destruction is in deethanizer, depropanizer, debutanizer composing the rectification section. So a detailed exergy analysis is developed for each section.

Improved Quality of Liquefied Petroleum Gas via Non-Stirred Blending

Liquefied Petroleum Gas (LPG) which contains more than 0.1% mole of butadiene is classified as a carcinogen and mutagen and regulatory have set the limit of butadiene to be below 0.5 % mole in LPG mixture. LPG suppliers in Malaysia are facing problem since butadiene level from one port exceeded 0.5 % mole. By blending of LPG from other ports might produce LPG products which satisfy the regulatory limit. The study focused on homogeneous blending time in a 17.28 m3 tank without artificial mechanical equipment through simulation modelling by Fluent 6.2.16 with two sources of LPG which were Ports A and B. The results showed that as the volume of LPG with butadiene increased, the butadiene level in mixed LPG also increased. The mass fraction between Ports A and B was below than 93% and 7% produced mixed LPG product within the regulatory limit. The blending time is approximately 3.98 hours to achieve homogeneous product mixture with a constant flow rate of 0.52 kg/s. Numerical modelling reveals that the effect of liquid-liquid diffusion by Wilke-Chang correlation does not significantly affect the blending time for homogeneous mixture. In fact the required blending time is shorter compared to blending time estimated by numerical modeling.

Simulation and optimization of an industrial gas condensate stabilization unit to modify LPG and NGL production with minimizing CO2 emission to the environment

In the present study, a great effort was made to improve the performance of an industrial liquefied petroleum gas (LPG) and natural gas liquid (NGL) production unit in one of the major gas refinery located at Pars special economic zone in Iran. To demonstrate and obtain the optimal condition, the unit was simulated by using a steady-state flowsheet simulator, i.e. Aspen Plus, under different operational conditions. According to the simulation results, the unit was not operational under its optimal conditions due to some defects in the cooling system at top stage of the debutanizer tower (DBT) during hot and humid seasons. Additionally, the vapor pressure of produced LPG and accordingly the amount of its flaring were decreased by reducing the temperature of debutanizer tower at top stages. In the optimization section, the DBT condenser and reboiler heat duty, temperature, and pressure were regulated as adjustable parameters. The simulation results demonstrated that by applying the optimum suggestion in the hot months, the reflux stream temperature was reached about 55°C which caused an efficient increment in LPG production (about 4%) with adjusting the propane component in LPG, based on the standard range as the plant criteria. Moreover, after applying modifications, about 750t of LPG product was saved from flaring during five hot months of the year, which resulted in 360000USD extra annual income for the company. Finally, from environmental point of view, this optimization caused to reduce 81t of CO2 emission to the environment. Therefore, the current investigation must be introduced as a friendly environmentally process.

A New Adsorption Process to Intensify Liquefied Petroleum Gas Recovery from Raw Natural Gas

Raw natural gas from gas wells typically consists of methane, gaseous hydrocarbons, acid gases, water, liquid hydrocarbons, etc. The raw natural gas must be purified to produce the pipeline quality dry natural gas for residential, commercial and industrial consumers. The existing natural gas processing often roughly separates the raw natural gas into gaseous phase dry natural gas and liquid-phase gas condensate without extracting the high-priced liquefied petroleum gas (LPG). And thus, the LPG is sold along with cheaper dry gas and natural gas condensate. In addition, the gas condensate, in which LPG components like propane and butane, are often stored under atmospheric pressure, and most LPG components will be burnt after escaping from the breathing valve, which will also harm the environment. Some companies have tried to add LPG production line by adding more columns, which is not feasible economically. We present a new chemical adsorption flowsheet to enhance the LPG recovery. A comparison between the two processes is made, and the result shows that the chemical adsorption process is highly economical.

The Production of LPG Using Low-octane Model-feed (n-Hexane) on Modified Unloaded and Pt-loaded MFI Zeolite Catalysts

Nowadays, many developing countries, particularly those non–oil producing ones, suffer from critical shortage of liquefied petroleum gas (LPG) that consists of various mixtures of propane plus butanes (C3H8 + C4H10). In the present communication, n-hexane was used as an n-paraffinic model hydrocarbon to be hydrocracked for LPG production that can be used both as a fuel in domestic heating appliances and also as high-octane gaseous motor fuels. Catalysts containing 0.15%Pt, 0.30%Pt, or 0.60%Pt loaded on H-MFI zeolite, aluminum-deficient MFI (AD-MFI), or hydrofluorinated MFI zeolite (F-MFI) were investigated. Also, the three unloaded modified zeolites were compared as catalysts for n-hexane hydroconversion, whereby the F-MFI catalyst exhibited superior catalytic activity by virtue of acquiring higher acid sites density and strength. The Pt/F-MFI catalysts also enjoy the highest activities by acquiring the highest acid sites density and strength as well as the highest Pt dispersion.

Analysis of Applicability of Nanosensors in Explosion and Fire Safety Systems of Liquefied Petroleum Gas Production, Storage, and Utilization Facilities. Part 2*

The basic characteristics of developed nanosensors of liquefied petroleum gas (LPG) vapors are submitted. The applicability of these devices in explosion and fire safety systems of LPG producing, storing, and utilizing facilities is analyzed.

Analysis of Applicability of Nanosensors in Explosion and Fire Safety Systems of Liquefied Petroleum gas Production, Storage, and Utilization Facilities. Part 1

Nanosensors of liquefied petroleum gas (LPG) vapors are systemized according to design features of their sensing elements. Three groups of these devices are distinguished. Brief accounts about a few nanosensors are given.

Reaction Processing of Fraction of Yanhua FCC Gasoline

By using fraction of Yanhua FCC gasoline as a feedstock, the effects of reaction temperature, weight hour space velocity, feedstock performance on yields of liquefied petroleum gas production, and aromatics and propylene are researched in a confined fluidized bed reactor. Aromatization index (AI) and competent parameter (CP) are first proposed to study the mechanistic pathways of aromatization reaction of fraction of Yanhua FCC gasoline. The experimental result shows AI values of FCC gasoline decrease with the increase of the reaction temperature under the same catalyst; CP values and the aromatization reaction function for the same catalyst increase with the increase of the reaction temperature. The isomerization reaction for fraction of Yanhua FCC gasoline has more advantage than that of the aromatization reaction.

Study of Hydrate Formation and Inhibition for LPG

Liquefied petroleum gas (LPG) has already been proved as an efficient fuel and feedstock for many chemical and petrochemical industries. Hydrate formation can create serious problems in the production, transmission, storage, and end-use of LPG. Hence an adequate knowledge on hydrate formation (i.e., the effects of moisture content and pressure on the hydrate formation temperature) is crucial to maintain the process conditions out of the hydrate formation region. However the study particularly on such aspects is scarcely available in literature. Therefore the effects of moisture content and pressure on the LPG hydrate formation temperature are studied extensively. A correlation is also developed to predict hydrate formation temperature for various LPG compositions. Hydrate inhibition performances of various inhibitors are also evaluated. Aspen-HYSYS process simulator is used to perform the study. The present study provides useful information to reduce the hydrate formation of LPG. DOI: http://dx.doi.org/10.3329/jce.v27i2.17804 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 2, December 2012: 60-64

Preparation of bio-fuels by catalytic cracking reaction of vegetable oil sludge

Biofuel production from vegetable oil is potentially a good alternative to conventional fossil derived fuels. Moreover, liquid biofuel offers many environmental benefits since it is free from nitrogen and sulfur compounds. Biofuel can be obtained from biomass (e.g. pyrolysis, gasification) and agricultural sources such as vegetable oil, vegetable oil sludge, rubber seed oil, and soybean oil. One of the most promising sources of biofuel is vegetable oil sludge. This waste is a major byproduct of vegetable oil factories. It consists of triglycerides (61%), free fatty acid (37%) and impurities (2%). The hydrocarbon chains of triglycerides and free fatty acid are mainly made up of C16 (30%) and C18 (36%) hydrocarbons. The others consist of C12–C17 hydrocarbon chains. Transesterification can help in converting vegetable oil sludge into biofuel. The disadvantage of this method is that a large amount of methanol is required. The alternative method for this conversion is catalytic cracking. The objective of this research is to evaluate and compare the pyrolysis process with cracking catalytic reaction of vegetable oil sludge by Micro-activity test MAT 5000 of Zeton-Canada.A ZSM-5/MCM-41 multiporous composite (MC-ZSM-5/MCM-41), was successfully synthesized using silica source extracted from rice husk. The material has the MCM-41 mesoporous structure, and its wall is constructed by ZSM-5 nanozeolite crystals. The porous system of the material includes pores of the following sizes: 5Å (ZSM-5 zeolite), 40Å (MCM-41 mesoporous material), and another porous system whose diameter is in the range of 100–500Å (mesoporous system) formed by the burning of organic compounds that remain in the material during the calcination process. This pore system contributes to an increase in the catalytic performance of synthesized material.The results of vegetable oil sludge cracking reaction show that the product consists of fractions such as dry gas, liquefied petroleum gas (LPG), gasoline, light cycle oil (LCO), and (heavy cycle oil) HCO, which are similar to those of petroleum cracking process.MC-ZSM-5/MCM-41 catalyst is efficient in the catalytic cracking reaction of vegetable oil sludge as it has higher conversion and selectivity for LPG and gasoline products in comparison to the pyrolysis process. Product distribution (% of oil feed) of cracking reaction over MC-ZSM-5/MCM-41 is coke (3.4), total dry gas (7.0), LPG (31.1), gasoline (42.4), LCO (8.9), HCO (7.2); and that of pyrolysis are coke (19.0), total dry gas (9.3), LPG (16.9), gasoline (28.8), LCO (13.7), and HCO (12.3).These results have indicated a new way to use agricultural waste such as rice husk for the production of promising catalysts and the processing of vegetable oil sludge to obtain biofuel.

LPG characterization and production quantification for oil and gas reservoirs

Liquefied petroleum gas (LPG) refers to the gas extracted and liquefied from the separator gas in a processing plant and mainly consists of propane (C 3) and butane (C 4). Many offshore projects have restrictions on flaring gases and special fiscal terms make extracted liquids significantly more valuable than oil and condensate in some cases, which in turn impact the economics of many projects. This paper for the first time systematically investigates LPG characterization and production quantification coupled together with reservoir simulation. Detailed calculations of LPG yields from both gas cap and solution gas are given. LPG yield of fluid is a function of the initial gas–oil ratio (GOR), gas specific gravity, and separator condition: LPG yield, which is lower in the gas cap compared to the solution gas of the same reservoir, has a good correlation with gas specific gravity and is impacted by separator conditions. The concept of LPG-produced GOR correlation curve is introduced and applied together with gas production rate to predict LPG production. Correlation curves depend on reservoir fluid properties and development strategies. Generated from flashing the mixtures of different proportions of oil and gas samples, LPG-produced GOR correlation curve has a good agreement with the results from reservoir compositional simulation and can be coupled with various forecasting tools in reservoir engineering. Lean gas injection has an insignificant impact on LPG recovery but can substantially improve the recovery of total liquid (oil and condensate). The paper also shows that lumping C 3 and C 4 as one pseudocomponent is suitable.

APUSM technology for the production of BTX and LPG from pyrolysis gasoline using metal promoted zeolite catalyst

SK Corporation developed an advanced pyrolysis gasoline (pygas) upgrading (APUSM) technology based on a catalytic process for producing valuable benzene, toluene and xylenes (BTX) and liquefied petroleum gas (LPG) from pygas containing aromatics and non-aromatic hydrocarbons. Hydrodealkylation of heavy aromatics and hydrocracking of non-aromatic hydrocarbons occurred with facility in the conversion of pygas over a proprietary catalyst, metal promoted zeolite. This catalytic process produced benzene and toluene with high purity corresponding to chemical grade while giving mixed xylenes with reduced ethylbenzene. In the present study, we described novel features of the APUSM technology in terms of the process and catalyst. The influence of the process conditions was also examined. This technology has been commercially proven, and hence is available for licensing through Axens, which is a major engineering and licensing company.