Propane Storage Research Articles

A Look into the Boil‐Off Gas Reliquefaction in Propane Storage Plants

AbstractThe reliquefaction process of boil‐off gas (BOG) in a propane plant using the reverse Brayton cooling cycle was examined by simulating the operational parameters and system performance of a propane reliquefaction plant in Aspen HYSYS software. The simulation considered various process and design parameters and their effects on the BOG production rate, energy consumption demand, and coefficient of performance (COP) of the cycle. The results demonstrate that the inclusion of methane in the propane product has a considerable impact on the generation of BOG, but this comes at a cost because power consumption increases significantly and the cycle's COP decreases. Furthermore, heat transmission from the surrounding air through the tank insulation and the temperature at which propane is returned from the jetty influence the BOG generation.

Adsorption Isotherms and Isosteric Heat of Adsorption of Metal Organic Frameworks as Gas Storage for Liquefied Petroleum Gas Vehicle in Iraq

This research provides a novel technique for using metal organic frameworks (HKUST-1) as a gas storage system for liquefied petroleum gas (LPG) in Iraqi vehicles to avoid the drawbacks of the currently employed method of LPG gas storage. A low-cost adsorbent called HKUST-1 was prepared and characterized in this research to investigate its ability for propane storage at different temperatures (25, 30, 35, and 40 oC) and pressures of (1-7) bar. HKUST-1 was made using a hydrothermal method and characterized using powder X-ray diffraction, BET surface area, scanning electron microscopic (SEM), and Fourier Transforms infrared spectroscopy (FTIR). The HKUST-1 was produced using a hydrothermal technique and possesses a high crystallinity of up to 97%, surface area 3400 m2/g, and pore volume 0.7 cm3/g. The prepared adsorbent (HKUST-1) tested using volumetric method, the maximum adsorption capacity of propane was (10.499 mmol/g) at a temperature of 298K and a pressure of 7 bar. Furthermore, adsorption isotherm study was conducted to understand the system equilibrium (i.e., the fitting with one of the known models Langmuir, Freundlich, and Temkin isotherm models). It was observed that the Freundlich isotherm model fitted well the experimental data. The Clausius-Clapeyron equation was used to determine the heat of adsorption, and the results revealed that the heat of adsorption increased as the propane adsorption capacity increased. The prepared HKUST-1, which has a large surface area and a high adsorption capacity, can be used as a major solution for gas storage for liquefied petroleum gas (LPG) in Iraqi vehicles.

Flame propagation behavior of propane–air premixed combustion in a confined space with two perforated plates at different initial pressures

AbstractThe aim of this paper is to analyze local autoignition induced by secondary flame acceleration. The secondary flame acceleration process and the local autoignition formation mechanism at the condition of the secondary flame acceleration propagation were investigated by utilizing an improved designed constant volume combustion bomb (CVCB) with two perforated plates. Primary flame and secondary flame propagation were recorded via high‐speed schlieren photography. The results showed that there were three distinct stages in the process of flame propagation through two perforated plates, which were the primary jet flame stage, secondary jet flame stage, and flame‐shock interaction stage. The morphologies of the flame were analyzed by high‐speed Schlieren images, flame velocities, and pressure oscillation including primary jet propagation, secondary flame formation and acceleration, and location autoignition. Results show the effect of initial pressure on flame propagation, flame velocity, and pressure oscillation. Acceleration of secondary flame and local autoignition phenomenon was more precisely demonstrated as unburnt gases were compressed by flame waves (different velocities) with initial pressure increasing. Based on the morphology of flame, three different types of flame combustion modes were captured at different initial pressure involving turbulent flame, deflagration, and quasi‐detonation. The present work might provide a new insight for combustion science in a confined space, such as autoignition due to compression effect of secondary jet flame and primary flame interaction. It also provides the theory guidance and research direction towards further studies on propane storage vessel deflagration.

Development of a risk informed quantitative decision making framework for major accident hazards installations in Sri Lanka

This paper proposes a risk informed decision-making framework for siting Major Accident Hazard Installations in Sri Lanka. It is named the “Upper Bound FN curve” method. Generic failure rate data are utilized as country specific data are not available. FN Curves are derived for each process node of a Major Accident Hazard Installation using different failure rate data sets available in literature. The data sets giving the “worst case” FN Curve for each process node is identified. These FN Curves are called the Upper Bound FN Curves. Using these curves, a composite FN Curve is developed which is compared against the country specific risk acceptance criterion line. If the risk is not acceptable, further safety barriers are introduced. Safety distances are then determined using a scaling factor developed in this study called the relative risk reduction factor (RRRF). The RRRF is determined based on the comparative position of the composite FN curve with respect to the criterion line. The proposed methodology was applied in a case study of liquefied propane storage tank. Guidelines for application of the proposed framework, interpretation of the “Upper Bound FN Curve” method and estimation of safety distances are presented.

Development of a predictive accident model for dynamic risk assessment of propane storage tanks

Investigation of past accidents has shown that LPG tank accidents cause significant damage to the industry due to the storage of large volumes of flammable materials in them. This study aimed for developing a predictive accident model for dynamic risk assessment of propane storage tanks of the refinery. Hazards and safety barriers were identified using MIMAH methodology. The basis of MIMAH methodology is Bow-tie method. To construct the Bow-tie diagram, first, accidents that occurred on LPG tanks were extracted from the databases of accidents and valid sources. The top events of the accidents were identified and analyzed by the fault tree. The Bow-tie diagrams were constructed and the barriers on the diagrams were identified and verified by refinery experts. According to the SHIPP model, safety barriers were categorized into seven main barriers. The failure rates of the fault tree basic events were extracted from reliable sources and the prior probability of barriers was calculated. Based on the failure or success of safety barriers, 6 levels of severity of consequences, safe, near miss, mishap, incident, and catastrophic accident were considered. Using the prior probability of failure of the barriers, the probability of occurrence of each level of severity of consequences was calculated with the event tree. In the next step, this paper employed LPG storage tanks past accidents to construct a likelihood function and update prior probability using the Bayesian equation. Finally, the posterior probability of occurrence of the consequences was calculated using the posterior probability of failure of the barriers. Because LPG accidents occur with low probability and high severity, predicting accidents dynamically helps people to always be prepared to prevent their occurrence.

A case study on optimum identification of water curtain hydraulic pressure using three-phase flow numerical simulation

Groundwater-sealed liquid propane storage cavern is usually built in crystalline rock mass. Water curtain system is an indispensable facility to ensure the containment efficiency of the cavern due to the strong heterogeneity of fractured rock mass and the special properties of stored product. In this study, a propane cavern in Yantai, Shandong province is selected as a study case to investigate the reasonable water curtain pressure. Stochastic mathematical method was applied to calculate the permeability coefficient of the study area. A vertical 2D three-phase flow model based on THOUGH2 is established to study the migration characteristics of the stored product under different water curtain pressure and the influence of water curtain pressure on the gas containment of the cavern. It was found that the leakage of stored product can be restrained effectively when the water curtain pressure is greater than or equal to 0.8 MPa. When the water curtain is greater than or equal to 1.2 MPa, part of water in the water curtain is discharged from the simulation area, which will reduce the utilization rate of water resources and increase the operating cost. Therefore, the reasonable range of horizontal water curtain pressure is 0.8~1.1 MPa under this case or similar condition. The geological conditions and the migration characteristics of stored product considered in this paper, and the reasonable range of water curtain pressure obtained as well, can provide a new reference and methodology for the optimum determination of water curtain pressure in groundwater-sealed cavern engineering to increase the efficiency and reduce the cost of the work.

The effect of blast-induced vibration on the stability of underground water-sealed gas storage caverns

Underground water-sealed gas storage caverns have become the primary method for strategic storage of LPG. Previous studies of excavation blasting effects on large-scale underground water-sealed gas storage caverns are rare at home and abroad. In this paper, the blasting excavation for underground water-sealed propane storage caverns in Yantai was introduced and field tests of blasting vibration were carried out. Field test data showed that the horizontal radial velocity had a major controlling effect in the blasting vibration and frequencies would not cause the vibration velocity concentration effects. In terms of the influence of blasting vibration on adjacent caverns, the dynamic finite element model in LS-DYNA soft was established, whose reliability was verified by field test data. The numerical results indicated the near-blasting side was primary zone for the structural failure and tensile failure tended to occur in the middle of the curved wall on the near-blasting side. Meanwhile, the safety criterions for adjacent caverns based on stress wave theory and according to statistic relationship between peak effective tensile stress and peak particle velocities were obtained, respectively. Finally, with Safety Regulations for Blasting in China (GB6722-2014) taken into account, a final safety criterion was proposed.

Assessing the hazards from a BLEVE and minimizing its impacts using the inherent safety concept

Many worlds' major process industry accidents are due to BLEVE such as at Feyzin, France, 1966 and San Juan Ixhuatepec, Mexico City, 1984. One of the approaches to eliminate or minimize such accidents is by the implementation of inherently safer design concept. This concept is best implemented where the consequence of BLEVE can be evaluated at the preliminary design stage, and necessary design improvements can be done as early as possible. Thus, the accident could be avoided or minimized to as low as reasonably practicable (ALARP) without resorting to a costly protective system. However, the inherent safety concept is not easy to implement at the preliminary design stage due to lack of systematic technique for practical application. To overcome these hurdles, this paper presents a new approach to assess process plant for the potential BLEVE at the preliminary design stage and to allow modifications using inherent safety principles in order to avoid or minimize major accidents. A model known as Inherent Fire Consequence Estimation Tool (IFCET) is developed in MS Excel spreadsheet to evaluate BLEVE impacts based on overpressure, radiation heat flux and missile effects. In this study, BLEVE impacts are the criteria used as the decision-making for the acceptability of the design. IFCET is integrated with iCON process design simulator for ease of data transfer and quick assessment of potential BLEVE during the design simulation stage. A case study was conducted to assess of potential BLEVE from a propane storage vessel at the design simulation stage using this new approach. The finding shows promising results that this approach has a potential to be developed as a practical tool.

English

The occurrence of incidents resulting from chemical releases requires preparatory measures. Despite special layers of protection in chemicalindustries to avoid such releases and subsequent consequences, human errors still occur and negatively contribute to failures in different activities include maintenance practices and operating control and so on. It is proven that one of the most devastating risk in the oil and gas companies is explosion, particularly BLEVE. Thus, the study of this phenomena and analysis of its consequences at various stages is necessary. Recent studies claimed that the predictionof damaging effectafter the explosion by mathematical models is necessary for its effective management. For this reason, we aim to analysis the consequence of BLEVE in high pressurized propane vessel (V- 3001/A) in order to be well prepared for further emergency activities and also implement further modifications. There are numerous software presented to model the consequences of chemical substances releases (Such as PHAST, ALOHA, SLAB, DEGADIS). Because of validation of modelling capabilities and a particular consideration of PHAST software for vessels' explosion, this software has been adapted to analysis BLEVE phenomena and its consequences in the Bandar Abbas condensate refinery of Iran. At first, expert team, including maintenance, plant, process, safety engineers and relevant operators held several meetings in order to define BLEVE scenario. Note to process flow diagram and design detail, the process parameters of propane storage tank (including; mass, volume, temperature, pressure, and so on) applied in the PHAST software (Version 6.7). In this model, the most dominant climatic condition in Bandar Abbas city has been defined (temperature, 42 o C, relative humidity, 90%, wind speed, 3.5 m/s). Finally, estimated losses caused by explosion wave in nearby facilities such as pumps, compressors, gas turbines, pipelines, spherical and cylindrical tanks have been assessed. The results of this study demonstrated that some of the surrounding facilities will be suffering from BLEVE's overpressure wave, while most of themwill be free from any damage (Blast wave pressure <0.1 psi). Thus, the authors recommended that protective wall around pipelines need to build to deter the imposed pressure. In addition, the dislocationof several cylindrical tanks would be helpful. Finally, we suggest that chain effects, radiation analysis, shock waves, and the effectiveness of corrective measures would be helpful for further study.

LOPA 및 SIF기법에 의한 LPG 인수기지의 안전성향상에 대한 연구

− The methods which decrease the accident hazards of LPG(Liquefied Petroleum Gas) terminal on the basis of butane & propane storage tanks by applying HAZOP(Hazard and Operability), LOPA(Layer of Protection Analysis) and SIL(Safety Integrity Level) are suggested. The accident scenarios were derived by analyzing latent risks through the HAZOP. The scenarios which would have the big damage effect in accidents were selected and then LOPA was assessed by analyzing IPL(Independent Protection Layer) about the correspond accident scenarios. The improved methods were proposed on the basis of level of SIF(Safety Instrumented Functions) as a IPL considering satisfied condition of risk tolerance criteria(1.0×10/y). In addition, The proposed IPLs were basis on the economic analysis. The effect of SIF as a IPL considering the changes of accident frequency was studied in case of the accident scenarios derived from the concerned process.

Domino effects at LPG and propane storage sites in the Netherlands

Dutch national standards play an important role in preventing domino accidents with hazardous substances, as they offer tabulations of calculated safety distances for several types of installations. This paper describes the way in which safety distances for LPG and propane storage sites were derived. The safety distances are published in two national standards (PGS 18 and 19).For LPG and propane storage sites, the most important type of domino accident is a fired BLEVE of the LPG or propane pressure vessel. Initiating events are pool fire, jet fire and fire from buildings (flat radiator). In PGS 18 and 19, safety distances are defined that should reduce the likelihood of a fired BLEVE. In this paper, we discuss the assumptions that were used to define these safety distances. Apart from providing sufficient separation between objects, additional measures exist to reduce the likelihood of domino events to LPG and propane vessels. The use of certain safety measures can lead to smaller safety distances.The aim of Dutch policy is that the national standards reduce the likelihood of domino effects to an acceptable level. Subsequently, domino effects do not have to be considered in quantitative risk analyses that are used for land-use planning.

Risk assessment of a propane storage sphere: Maintain or decommission?

The authors were asked to assist a utility with a risk man-agement decision. Specifically, the utility was consideringwhether they should maintain or decommission an 800,000gallon propane storage sphere. The 30-year old sphere wasthe fuel storage vessel for a propane standby system. One oftheir major concerns was the shrinking buffer zone aroundtheir facility. Although the facility was originally located in aremote rural area, residential development had begun toencroach upon the facility’s buffer zone.The original analysis was based on a consideration of theoffsite consequences for a worst-case scenario. This was doneat the request of the client as it reflected their degree of riskacceptance. The consequences of two hazard scenarios wereanalyzed: an unconfined vapor cloud explosion and a Boil-ing Liquid Expanding Vapor Explosion (BLEVE). To supportthis analysis, the mechanical integrity of the sphere was eval-uated deterministically by considering the pressure vesseldesign documents, the limited nondestructive test and evalu-ation data available, and published data on typical corro-sion rates. Additional factors incorporated into the analysiswere the capabilities of the existing fire protection system, thefacility security system, and the propane unloading stationfor tank car deliveries. Finally, the economics of maintainingthe sphere versus decommissioning it were explored. Ulti-mately, the utility decided to decommission the sphere.In this article, we conduct a retrospective study using arisk-based approach. We identify a set of hazard scenariosfor the propane storage sphere, calculate the leak frequencyfor each scenario, compute the associated source term, andevaluate the consequences. The results are compared with theoriginal consequence analysis and other published hazardstudies. The implications for risk management are discussed.

Prioritization of disaster risk in a community using GIS

Prioritization of disaster risk was carried out for a community in Toronto, Canada. Geographic information systems (GIS) were used for spatial analysis, including spatial overlays and clipping for extracting spatial and attribute information related to people’s vulnerability, critical infrastructure and landuse. In order to determine disaster risk, the overall community vulnerability was evaluated by combining social, economic, physical and environmental vulnerabilities. This paper uses the propane explosion incident as the case in point to demonstrate the methodology and procedure used to evaluate risk using GIS techniques. City of Toronto spatial data have been integrated with the study area to gather landuse information, identify risk zones based on the propane storage facility location and evaluate risks. Statistics Canada 2006 census data have been used for area demographics and people’s social and economic status. Vulnerability indicators were determined based on the GIS-derived spatial and attribute data for the hazard and evacuation zones followed by a quantitative spatial risk estimation and ranking. The methodology of this study, based on the risk evaluation and prioritization conducted, can be applied to future decision making in effective landuse planning and the development of risk management strategies.

Metallurgical failure analysis of a propane tank boiling liquid expanding vapor explosion (BLEVE)

A severe fire and explosion occurred at a propane storage yard in Truth or Consequences, N.M., when a truck ran into the pumping and plumbing system beneath a large propane tank. The storage tank emptied when the liquid-phase excess flow valve tore out of the tank. The ensuing fire engulfed several propane delivery trucks, causing one of them to explode. A series of elevated-temperature stress-rupture tears developed along the top of a 9800 L (2600 gal) truck-mounted tank as it was heated by the fire. Unstable fracture then occurred suddenly along the length of the tank and around both end caps, along the girth welds connecting the end caps to the center portion of the tank. The remaining contents of the tank were suddenly released, aerosolized, and combusted, creating a powerful boiling liquid expanding vapor explosion (BLEVE). Based on metallography of the tank pieces, the approximate tank temperature at the onset of the BLEVE was determined. Metallurgical analysis of the ruptured tank also permitted several hypotheses regarding BLEVE mechanisms to be evaluated. Suggestions are made for additional work that could provide improved predictive capabilities regarding BLEVEs and for methods to decrease the susceptibility of propane tanks to BLEVEs.

The Effect of Reduced Design Margin on the Fire Survivability of ASME Code Propane Tanks

In the 1999 addenda to the 1998 ASME pressure vessel code, Section VIII, Div. 1 there was a change in design margin for unfired pressure vessels from 4.0 to 3.5. This has resulted in the manufacture of propane and LPG tanks with thinner walls. For example, the author has purchased some new 500 gallon ASME code propane tanks for testing purposes. These tanks had the wall thickness reduced from 7.7 mm in 2000 to 7.1 mm in 2002 and now to 6.5 mm in 2004. These changes were partly due to the code change and partly due to other factors such as steel plate availability. In any case, the changes in wall thickness significantly affects the fire survivability of these tanks. This paper presents both experimental and computational results that show the effect of wall thickness on tank survivability to fire impingement. The results show that for the same dank diameter, tank material, and pressure relief valve setting, the thinner wall tanks are more likely to fail in a given fire situation. In severe fires, the thinner walled tanks will fail earlier. An earlier failure usually means the tank will fail with a higher fill level, because the pressure relief system has had less time to vent material from the tank. A higher liquid fill level at failure also means more energy is in the tank and this means the failure will be more violent. The worst failure scenario is known as a boiling liquid expanding vapor explosion and this mode of failure is also more likely with the thinner walled tanks. The results of this work suggest that certain applications of pressure vessels such as propane transport and storage may require higher design margins than required by Section VIII ASME code.

Portable PEFC generator with propane as fuel

Propane is a typical widespread fuel, which is often used for camping applications, because it can be transported easily and be stored in liquid form in pressure vessels for mobile and portable use. Propane as feedstock for hydrogen production offers a new way to a cheap fuel for fuel cells. The generation of a PEFC hydrogen fuel gas can be perfomed by catalytic cracking of propane. The decomposition of the liquified hydrocarbon takes place at temperatures above 800°C at atmospheric pressure. A fuel processor based on this simple concept can be built much smaller and less expensive than existing ones using steam reforming technology. A propane cracking system works without shift-conversion, gas purification for removal of CO and without a steam generator. The removal of small amounts of CO from the hydrogen rich gas produced is possible by using a simple methanation step. A low cost portable fuel cell device is under development consisting of a polymer electrolyte fuel cell, a hydrogen production system based on catalytic cracking of propane, a propane storage container and an electronic control unit. Combined with a fuel cell providing 200 W gross electric power, a net power output of about 130 to 160 W can be achieved. The PEFC used will contain low cost bipolar plates made of carbon–polymer composite materials.

The clean air act section 112(r) risk management plans: Compliance requirements and alternatives

AbstractSection 112(r) of the Clean Air Act Amendments of 1990 included significant compliance provisions for facilities to manage chemical process risk. The regulation promulgated by EPA, commonly referred to as the “Risk Management Plan” rule, will require a substantial fiscal, experiential, and human resource investment for installations that are required to comply. Primarily, most military installations that have to comply will do so for water disinfection or propane storage. In addition to regulatory liability, Section 112(r) rules also have a significant public affairs and facility security aspect. This article reviews the regulation to point out compliance challenges and presents methods for reducing or eliminating the need to be subject to the rule by employing safer, smarter business practices.

Experimental determination of the droplet size and velocity distributions at the exit of the bottom discharge pipe of a liquefied propane storage tank during a sudden blowdown

In 1991, the Commission of the European Communities launched a series of projects specifically aimed at the understanding of chemical hazards. This was called the STEP Program and covered projects on hazard analysis to determine the consequences of releases of flammable pressurized and liquefied gases. In that frame, the present study concerns the experimental determination of the droplet size and velocity distributions within a jet at the exit of a discharge pipe of a liquefied propane storage tank during a sudden blowdown. For this purpose, a Phase Doppler Particle Analyzer (PDPA) was used to measure liquid drop size and velocity. Due to the high drop concentration in the jet, it was necessary to protect the incident laser beams and the light scattered by particles to make the measurements possible. In such conditions, a set of blowdowns was performed by varying the nozzle diameter, the initial pressure inside the storage vessel and the measurement position in the jet. These tests include on- and off-axis measurements. The results are presented, showing the droplet evaporation and the velocity evolution inside the jet. This work provides original data which can be useful for the validation of vapour cloud dispersion codes.

PROPANE THERMAL INJURIES

"Burn-like" propane thermal injury is produced by evaporative heat loss causing damage to vital structures. Acute appearance is that of heat burn with progressive vascular compromise. Histopathologic study demonstrates epidermal and dermal necrosis followed by vascular thrombosis. Physicians should be aware of this injury and its consequence in light of the widespread use of pressurized propane storage.

Performance of a high pressure propane storage cavern in unlined rock, Rafnes, Norway : Johansen, P M; Kjaernsli, B; Lien, R In: Norwegian hard rock tunnelling. Norwegian soil and rock engineering association publicationN1, P51–54. Publ Trondheim: Tapir Publishers, 1982

Performance of a high pressure propane storage cavern in unlined rock, Rafnes, Norway : Johansen, P M; Kjaernsli, B; Lien, R In: Norwegian hard rock tunnelling. Norwegian soil and rock engineering association publicationN1, P51–54. Publ Trondheim: Tapir Publishers, 1982