Gas Refinery Plant Research Articles

Energy, exergy, economic, and environmental analysis of natural gas sweetening process using lean vapor compression: a comparison study

Abstract Gas sweetening with an aqueous solution of diethanolamine is a crucial and common process in natural gas processing. However, the process, particularly in the solvent regeneration section, consumes a substantial amount of energy, significantly escalating the cost of gas. This paper presents a simulation and optimization of an existing natural gas refinery plant using a lean vapor compression method. The simulation results indicate that the current process requires 2.73 GJ/tacid gas for solvent regeneration, with exergy destruction of 14,120.59 kW in the solvent regeneration section. The total annualized cost for the current process is 11.68 M$. A modified scheme is proposed to address the issue of high energy consumption and the associated costs. The proposed scheme demonstrates significant improvements in the aforementioned parameters. Specifically, energy for solvent regeneration, exergy destruction in the solvent regeneration section, total annualized cost, and cost of gas are reduced by 16.12 %, 25.04 %, 20.97 %, and 20 % compared to the current process, respectively. These improvements enhance the thermoeconomic indexes, making the proposed scheme a viable and cost-effective alternative to the current process.

Exergy and Exergoeconomic Assessment of an Acid Gas Removal Unit in a Gas Refinery Plant

Exergy and Exergoeconomic Assessment of an Acid Gas Removal Unit in a Gas Refinery Plant

A Reactivity Based Emission Inventory for the South Pars and Its Implication for Ozone Pollution Control

The South Pars zone in Iran encompasses the largest gas refineries and petrochemical complexes in the world. In the South Pars zone, elevated concentrations of reactive hydrocarbons co-emitted with nitrogen oxides from industrial facilities lead to substantial ozone production downwind. To understand the role of these emissions on the ozone formation and, to formulate appropriate control strategies in this zone, emissions of precursors of ozone were quantified, and compounds that deserve relatively more attention were determined. To do this, first, a fully- speciated ozone precursors emission inventory was prepared to provide necessary input data for air quality simulation models. Then, the emission inventory was weighted by emitted mass and incremental reactivity scales to determine which compounds deserve relatively more detailed representation in the modeling. Afterward, a photochemical model was applied to determine the ozone sensitivity to its precursors. Finally, source apportionment was done for the most important compounds. Additionally, the reactivity-based inventory was compared with other regions. Results show that nitrogen oxides -sensitive chemistry is dominant in the zone thus the most effective control strategy is the mitigation of the nitrogen oxides emissions. Gas refinery plants have a larger share than petrochemical plants in the nitrogen oxides emission and, the gas turbines are the main sources of nitrogen oxides emission in this region. Emitted volatile organic compounds contain more highly reactive species in comparison with the ambient air composition of typical urban areas and areas with gas production industries. Propylene and ethylene have the most contribution to the ozone formation in comparison with other volatile organic compounds. The major sources of their emissions are the olefin processes and polymer production plants.

Determination of the Pollution Free Areas Due to Chemical Release from Oil & Gas Refinery Plant, Kerteh, Terengganu

Determination of the Pollution Free Areas Due to Chemical Release from Oil & Gas Refinery Plant, Kerteh, Terengganu

Effects of Various Earth Grid Configurations on Ground Potential Rise Caused by Lightning Strike

Ground Potential Rise (GPR) caused by lightning strike is a potential hazard for electrical equipment inside an oil and gas refinery plant. In order to mitigate the risk, horizontal grounding grid is applied. The best mitigation is to install a grounding grid with mesh size as small as possible. This condition requires a high cost. In order to obtain the optimal mesh size, a series of simulation of a grounding grid with mesh size variations on GPR caused by lightning strike has been carried out. CDEGS software was used to observe the GPR with various mesh size from 6.5 x 6.5 m to 20 x 20 m. Simulation results show that the maximum transient GPR rises as the grounding grid mesh size is increased, while the GPR distribution throughout the grounding grid area does not change much for different mesh sizes. In the other hand, decreasing the grid size would mean that more conductors are required, hence the cost would increase accordingly. The result shows that grid sizes from 6.5 x 6.5 m up to 20 x 20 m have no significant difference in term of GPR. In term of cost, 10 x 10 m does not show significant difference with 20 x 20 m, on the other hand, there is a significant difference for grid sizes 1 x 1 m to 10 x 10 m. From the results, grid sizes between 10 x 10 m up to 20 x 20 m are still applicable as stated in Petronas Technical. To comply with proper GPR value, additional protection devices are needed to protect the electrical equipment from potential damage.Keywords –GPR, grounding grid, mesh size

CFD modeling of industrial cold box with plate-fin heat exchanger: Focusing on phase change phenomenon

Cold box with plate-fin heat exchanger (PFHE) is extensively used in liquefied natural gas (LNG) refinery plants. In the present study, a CFD model in ANSYS FLUENT is developed for better understanding the transport phenomena, especially the phase change, in a quite complex plate-fin heat exchanger operated in a gas refining company. The flow channels, ducts and passes of the cold box, are considered in the computational geometry. The porous media technique is introduced in the computational domain due to the excessive increase in the number of computational grids when the fins accounted for in the numerical domain. The flash calculations (FC) technique is coupled with CFD in evaluation of chemical species in the cold box by a user defined function. This study examines the importance of local thermal equilibrium between the porous medium and fluid flow without mass transfer (LTE-non mass), local thermal equilibrium between the porous medium and fluid flow with mass transfer (LTE), and local thermal non equilibrium between the porous medium and fluid flow with mass transfer (LTNE) in simulation of an industrial cold box. Numerical results are compared with the corresponding operational data and the best agreement is obtained by the LTNE approach. The calculated mean relative errors of the LTNE approach for the outlet vapor fraction of streams A, hot stream, B and C, sided cold streams, are 0.15, 0.352, and 0.173%, respectively.

Measuring Workload in a Multitasking Environment Using Fractal Dimension of Pupil Dilation

ABSTRACTThe purpose of this study is to investigate the usefulness of the fractal dimension of pupil dilation as a measure of workload in a multitasking environment. Researchers have found that pupil dilation can reveal the underlying mechanism of the cognitive workload in a dynamic task environment. However, the workload metrics by using pupillary responses in a multitasking environment are not well studied in the literature. In this study, the participants’ pupil dilation was collected and analyzed by using a fractal analysis technique to assess the participants’ workload during the experiment. During the experiment, each participant performed a process monitoring task and Multi-Attribute Task Battery (MATB) task together. The process monitoring task simulated the responsibilities of process operators in the control room of oil and gas refinery plants. The MATB task consisted of system monitoring, target tracking, and dynamic resource management. To validate the outcome of this new metric, NASA-TLX questionnaires were used to measure the subjective workload, and the result of NASA-TLX was compared to the fractal dimension result. The findings from this study showed that the fractal dimension of pupil dilation could be used as a new physiological index to measure the workload in a multitasking environment.

DEVELOPING GIS-BASED DISASTER MANAGEMENT SYSTEM FOR LOCAL AUTHORITY – CASE STUDY IN MALAYSIA

Abstract. This paper describes the development of geospatial-based disaster management system for an agency at regional level. Important aspects of the system such as spatial data, geospatial database, interface and specific modules for the disaster management system form major discussions of this paper. The Pengerang Disaster Management System (PDMS) is being developed for a local authority in one of the Malaysian states who’s been given a task to monitor the surrounding environmental aspects. The local authority manages one of the largest oil and gas refinery plant in South East Asia region in collaboration with national oil company, PETRONAS. The PDMS, is a one-stop centre (dashboard) for managing the operations with other agencies or stakeholders such as police, marine, army, medical team, fire and rescue units. We anticipate many aspects of disaster management could trigger from this pilot project and thus provide some interesting ideas for a local authority in managing man-made disaster such as fire, other oil and gas related incidents. Some features of the developed system such as online map publishing services, data flow and other geospatial analysis during the event will be discussed in this paper. Near-future work and a big picture of the disaster management approach (with an emphasis to oil and gas incident and scenario) also will be highlighted.

Hazard Identification and Risk Assessment in Two Gas Refinery Units

Background: The analysis of causes and consequences of past accidents in gas refinery plants has indicated that the consequences of accidents in these plants may be catastrophic and irreversible, influencing human health, environment, and the economy. This study aimed at assessing risks using layer of protection analysis (LOPA) in gas sweetening units of 2 different gas refinery plants and determining the probability of initiating events with application of protection layers, using the event tree analysis (ETA) method. Methods: Hazard and operability (HAZOP) analysis was used in hazard identification. Data obtained from HAZOP analysis was applied to assess risks using the LOPA technique. The most likely scenarios were selected and the probability and consequences of initial events were determined using the ETA method. Results: Results of the HAZOP method led to identification of 52 risks and their levels in processes of both gas sweetening units, considering the control equipment. The results of LOPA showed that the levels of risk with different scenarios of both gas sweetening towers were similar. The probability of the total near misses in plant 1 and 2 were 0.00214753 and 0.00214149, respectively. The probabilities of incidents according to the top events in refinery 1 and 2 were 0.0000011 and 0.000005, respectively. Conclusions: The LOPA is a useful tool for the assessment of effectiveness of independent protection layers in reducing risk in both studied refinery plants. The results indicated that event tree analysis is an effective tool for quantitative analysis of consequences and probabilities of accidents in the studied gas refinery units.

Development of a framework for resilience measurement: Suggestion of fuzzy Resilience Grade (RG) and fuzzy Resilience Early Warning Grade (REWG).

Resilience engineering (RE) can be an alternative technique to the traditional risk assessment and management techniques, to predict and manage safety conditions of modern socio-technical organizations. While traditional risk management approaches are retrospective and highlight error calculation and computation of malfunction possibilities, resilience engineering seeks ways to improve capacity at all levels of organizations in order to build strong yet flexible processes. Considering the resilience potential measurement as a concern in complex working systems, the aim of this study was to quantify the resilience by the help of fuzzy sets and Multi-Criteria Decision-Making (MCDM) techniques. In this paper, we adopted the fuzzy analytic hierarchy process (FAHP) method to measure resilience in a gas refinery plant. A resilience assessment framework containing six indicators, each with its own sub-indicators, was constructed. Then, the fuzzy weights of the indicators and the sub-indicators were derived from pair-wise comparisons conducted by experts. The fuzzy evaluating vectors of the indicators and the sub-indicators computed according to the initial assessment data. Finally, the Comprehensive Resilience Index (CoRI), Resilience Grade (RG), and Resilience Early Warning Grade (REWG) were established. To demonstrate the applicability of the proposed method, an illustrative example in a gas refinery complex (an instance of socio-technical systems) was provided. CoRI of the refinery ranked as "III". In addition, for the six main indicators, RG and REWG ranked as "III" and "NEWZ", respectively, except for C3, in which RG ranked as "II", and REWG ranked as "OEWZ". The results revealed the engineering practicability and usefulness of the proposed method in resilience evaluation of socio-technical systems.

Development and analysis of two novel methods for power generation from flare gas

This study is aimed to develop two feasible scenarios to reuse the flare gases. The conditions of gas flaring in a real gas refinery plant are measured and two feasible structures for electrical power generation from the flare gas are investigated as two scenarios. The first scenario is burning the mixture of the flare gas and a conventional fuel, while the second one is sending the flare gas to an intermediate stage of a gas turbine after burning it in a combustor. In order to improve the power generation and mitigate the environmental issues, a steam power cycle is coupled as a bottoming cycle in both scenarios. By considering the power generation status and parametric study through an EES coding, the scenarios are studied and compared. Considering the flow rate of the flare gas which is variable with respect to time, the results show that the first scenario is preferable from technical and economic aspects for all of the flare and natural gas flow rates except when the amount of flare flow rate in the plant is lower than 0.8kg/s.

A STUDY ON THE ESTABLISHMENT AND IMPLEMENTATION OF CONSERVATION PROGRAM IN ARUN LNG PLANT

Energy conservation is an important issue in all sectoral activities, especially in processing industries such as natural gas refinery and liquefaction plant, petrochemical and cement mill in which energy isused in large amount. This paper presents a discussion on the experience in establishment and implementation the energy conservation program, including the reduction of greenhouse gas (GHG) emission achieved in the last four years in Arun LNG Plant, a commercial natural gas liquefaction plant in Aceh, Indonesia with a capacity of 2.2 million ton LNG per year. In addition, an analysis on the specific energy consumption and CO2 reduction is provided. The Energy Management Matrix was adopted in assessment of the energy management implementation in theArun LNG Plant. It was found that the efficiency of the plant tended to decrease from year to year, which was represented by the specificity of fuel consumption (accounted based on the LNG product). In 2010 the specific fuel consumption was 0.0088 mmscf per m3 LNG product; it was up to 0.0234 in 2013. Fortunately, it was observed that the specific CO2 reduction (calculated on the LNG product basis) increased during tlast four years; in 2010 and 2013 the specific CO2 reduction was 0.195 and 0.518 ton per 105 m3 LNG produced, respectively.

Risk assessment of industrial hydrocarbon release and transport in the vadose zone as it travels to groundwater table: A case study

In this paper, a modeling tool for risk assessment analysis of the movement of hydrocarbon contaminants in the vadose zone and mass flux of contamination release into the groundwater table was developed. Also, advection-diffusion-reaction equations in combination with a three-phase equilibrium state between trapped air, soil humidity, and solid particles of unsaturated soil matrix were numerically solved to obtain a one dimensional concentration change in respect to depth of soil and total mass loading rate of hydrocarbons into the groundwater table. The developed model calibrations by means of sensitivity analysis and model validation via data from a site contaminated with BTEX were performed. Subsequently, the introduced model was applied on the collected hydrocarbon concentration data from a contaminated region of a gas refinery plant in Booshehr, Iran. Four different scenarios representing the role of different risk management policies and natural bio-degradation effects were defined to predict the future contaminant profile as well as the risk of the mass flux of contaminant components seeping into the groundwater table. The comparison between different scenarios showed that bio-degradation plays an important role in the contaminant attenuation rate; where in the scenarios including bio-degradation, the contaminant flux into the ground water table lasted for 50 years with the maximum release rate of around 20 gr per year while in the scenarios without including bio-degradation, 300 years of contaminant release into groundwater table with the maximum rate of 100 gr per year is obtained. Risk assessment analysis strongly suggests a need for bioremediation enhancement in the contaminated zones to reduce the contaminant influx to groundwater.

Phytoremediation of heavy metals (Cd, Pb and V) in gas refinery wastewater using common reed (Phragmitis australis)

Industrial wastewaters are of the major sources of heavy metal pollution in the environment. In the Middle East, gas and oil industry is the major source of heavy metal pollution and releases significant amounts of metals into the terrestrial and aquatic environment. In this research the capability of the common reed ( Phragmitis australis ) in absorbing heavy metals Cd, Pb and V from the wastewater of a gas refinery plant in Iran was investigated. The plant samples were collected from the vicinity of the Bidboland gas refinery plant in Iran and were used for the treatment of wastewaters collected from the outflow of the refinery plant. The metal concentrations were measured in the roots of the plant species before treatment and after 2, 6 and 10 days of treatment procedure. The heavy metal concentrations were measured after acid digestion and using an ICP-OES instrument. After 10 days of treatment, the concentrations of the metals in plant tissues increased by 2.5, 6.9 and 2.7 times for Cd, Pb and V, respectively. The best treatment time was suggested to be 6 days. The common reed was observed to have a very good capability in removing heavy metals from the gas refinery wastewater.

Using Signal Detection Theory and Time Window-based Human-In-The-Loop simulation as a tool for assessing the effectiveness of different qualitative shapes in continuous monitoring tasks

This paper provides a case study of Signal Detection Theory (SDT) as applied to a continuous monitoring dual-task environment. Specifically, SDT was used to evaluate the independent contributions of sensitivity and bias to different qualitative gauges used in process control. To assess detection performance in monitoring the gauges, we developed a Time Window-based Human-In-The-Loop (TWHITL) simulation bed. Through this test bed, we were able to generate a display similar to those monitored by console operators in oil and gas refinery plants. By using SDT and TWHITL, we evaluated the sensitivity, operator bias, and response time of flow, level, pressure, and temperature gauge shapes developed by Abnormal Situation Management® (ASM®) Consortium (www.asmconsortium.org). Our findings suggest that display density influences the effectiveness of participants in detecting abnormal shapes. Furthermore, results suggest that some shapes elicit better detection performance than others.

Integration of qualitative and quantitative risk assessment methods for gas refinery plants

This paper focuses on the development of an integrated risk assessment system to increase the safety of gas refinery plants. This integration is important in managing the design and the operation of chemical plants and it requires significant time, effort and specialized expertise. We propose a systematic procedure to apply quantitative and qualitative hazard identification methods before constructing the refinery plants. Advantages of this assessment procedure are 1) systematic method in identifying most of the important hazards, 2) complete and rigorous analysis, and 3) reducing budget and time. The qualitative and quantitative assessment method consists of two and three steps, respectively. After these five steps, the risk of the same plant was calculated and analyzed. This method can identify risk and potential hazards from local gas refinery plants effectively and systematically. We applied the integrated qualitative and quantitative risk assessment method to remove the risk of a local gas refinery plant with 160 P&ID sheets. The result of this work confirmed that no residential population existed within the bounds of the 1×10−6 per annum risk contour. Therefore, the risk to the public from the gas refinery plants should be considered acceptable.

Wireless Sensor Network Modeling and Deployment Challenges in Oil and Gas Refinery Plants

Wireless sensor networks for critical industrial applications are becoming a remarkable technological paradigm. Large-scale adoption of the wireless connectivity in the field of industrial monitoring and process control is mandatorily paired with the development of tools for the prediction of the wireless link quality to mimic network planning procedures similar to conventional wired systems. In industrial sites, the radio signals are prone to blockage due to dense metallic structures. The layout of scattering objects from the existing infrastructure influences the received signal strength observed over the link and thus the quality of service (QoS). This paper surveys the most promising wireless technologies for industrial monitoring and control and proposes a novel channel model specifically tailored to predict the quality of the radio signals in environments affected by highly dense metallic building blockage. The propagation model is based on the diffraction theory, and it makes use of the 3D model of the plant to classify the links based on the number and density of the obstructions surrounding each individual radio device. Accurate link classification opens the way to the optimization of the network deployment to guarantee full end-to-end connectivity with minimal on-site redesign. The link-quality prediction method based on the classification of propagation conditions is validated by experimental measurements in two oil refinery sites using industry standard ISA SP100.11a compliant devices operating at 2.4 GHz.

Project risk identification and assessment simultaneously using multi-attribute group decision making technique

The identification and assessment of project risks among potential risks can be considered a multi-attribute group decision making (MAGDM) problem including both quantitative and qualitative criteria. We extend the concept of safety to risk identification and assessment; this is to emphasize that the focus should not only be on the time and cost criteria, but also on the health, safety and environment (HSE) criterion. Conventional approaches to risk identification and risk assessment separately tend to be less effective in dealing with the imprecise of the risk assessment individually. The aim of this paper is to present a new methodology for identifying and assessing risks simultaneously by applying MAGDM technique. This paper includes a new procedure for classifying potential risks which it is named potential risk breakdown structure (PRBS) based on project work breakdown structure (WBS). Nominal group technique (NGT) is utilized for gathering potential risks. Obtained results have been applied in gas refinery plant construction successfully.

A fuzzy decision-making model for risk ranking with an application to an onshore gas refinery

This paper aims to identify the important risks in Iranian onshore gas refinery plants and introduce new effective criteria. Risks are prioritised on the basis of the significance of impacts on typical project objectives in terms of cost, time, quality, safety and environmental sustainability. Then, this problem is defined in the Fuzzy Multicriteria Decision-Making (FMCDM) field. The Fuzzy Technique for Order Preference by Similarity to Ideal Solution (FTOPSIS) and Fuzzy Linear Programming Technique for Multidimensional Analysis of Preference (FLINMAP) methods are presented to rank the high risks. These two FMCDM modelling mechanisms are compared to find the better performance in project risk ranking. Moreover, a case study was conducted on the procedure of the proposed model and the results indicate that fuzzy LINMAP outperforms fuzzy TOPSIS. Therefore, the ranks of risks differ from one MCDM model to another. The selection of a proper MCDM model for risk ranking depends on the project's nature, the accuracy of data gathered on risk and experience.