Natural Gas Transmission Lines Research Articles

Real-Time Electrochemical Monitoring of the Progress of Sulfate Reducing Bacterially Induced Corrosion of Carbon Steel

Microbiologically influenced corrosion (MIC) is a widespread problem in the oil and gas industry, and sulfate reducing bacteria (SRB) cause the most aggressive kind of corrosion. A sulfate-reducing enrichment culture was obtained from a natural gas transmission line, and incubated in split chamber-zero resistance ammetry incubations. Here, carbon steel electrodes were placed in a synthetic gas field brine in opposing chambers that were connected with a salt bridge. To mimic the heterogeneous metal coverage of a metal surface that causes MIC, one chamber was experimentally manipulated with the addition of the SRB culture, while the other was uninoculated. Initial measurement of positive current between the electrodes in incubations with an organic electron donor (lactate) indicated a period of priming of the metal surface by planktonic SRB, before the current transitioned to negative, indicating that the cathodic corrosive reaction was occurring on the electrode exposed to SRB activities. This negative current is consistent with hypothesized mechanisms of SRB-induced corrosion and was observed in lactate-free incubations and in uninoculated incubations amended with sulfide. These observations, combined with SRB metabolic patterns and mass loss analyses indicate the dynamic nature of SRB-mediated corrosion and illustrate the utility of real-time monitoring of MIC activities.

Solar hydrogen for high capacity, dispatchable, long-distance energy transmission – A case study for injection in the Greenstream natural gas pipeline

This paper presents the results of techno-economic modelling for hydrogen production from a photovoltaic battery electrolyser system (PBES) for injection into a natural gas transmission line. Mellitah in Libya, connected to Gela in Italy by the Greenstream subsea gas transmission line, is selected as the location for a case study. The PBES includes photovoltaic (PV) arrays, battery, electrolyser, hydrogen compressor, and large-scale hydrogen storage to maintain constant hydrogen volume fraction in the pipeline. Two PBES configurations with different large-scale storage methods are evaluated: PBESC with compressed hydrogen stored in buried pipes, and PBESL with liquefied hydrogen stored in spherical tanks. Simulated hourly PV electricity generation is used to calculate the specific hourly capacity factor of a hypothetical PV array in Mellitah. This capacity factor is then used with different PV sizes for sizing the PBES. The levelised cost of delivered hydrogen (LCOHD) is used as the key techno-economic parameter to optimise the size of the PBES by equipment sizing. The costs of all equipment, except the PV array and batteries, are made to be a function of electrolyser size. The equipment sizes are deemed optimal if PBES meets hydrogen demand at the minimum LCOHD. The techno-economic performance of the PBES is evaluated for four scenarios of fixed and constant hydrogen volume fraction targets in the pipeline: 5%, 10%, 15%, and 20%. The PBES can produce up to 106 kilotonnes of hydrogen per year to meet the 20% target at an LCOHD of 3.69 €/kg for compressed hydrogen storage (PBESC) and 2.81 €/kg for liquid hydrogen storage (PBESL). Storing liquid hydrogen at large-scale is significantly cheaper than gaseous hydrogen, even with the inclusion of a significantly larger PV array that is required to supply additional electrcitiy for liquefaction.

ON GOING COALBED METHANE (CBM) DEVELOPMENT IN THE SOUTH SUMATRA BASIN

Coalbed methane (CBM) is going to be an important facet of the nation’s energy mix. It is expected to contribute in importance energy back up for the future. CBM is natural gas, a clean-burning energy source that is reservoired in a coal seam. CBM is formed during the coal maturation process and may in a free or adsorbed state in coal seams in adjacent formations. CBM is dominantly methane but lesser concentrations of carbon dioxide and nitrogen, compare to conventional natural gas. However, in most cases, CBM is of sufficient quality for sale directly into natural gas transmission lines with a limited amount of moisture removal.CBM as natural gas has numerous benefits to include direct selling, well suited as city gas, electricity generation, boiler fuel, transportation fuel, and for many types of chemical industries feed. Beside CBM replaces coal to be greatly reduces the production of acid rain and other forms of air pollution, the development of CBM has benefitial for coal miners. It can contribute to improved mining safety as well as it can help reduce construction costs.CBM is probably one of the promising alternative fuel energy resources in Indonesia that its presence is actual and comparable with the existing coal resources in any potential basin. Unlike some well in developed countries where commercialization of methane production from coal seam has been developed, coals direct mined in Indonesia seem to be more attractive and preferable technique to supply the consumer demand of energy. This is because coal mines serve direct products, less complicated technology, low exploration risks, easy recovery, relatively low cost but quick yields and already have wide market. Consequently, people have overlooked the existence of consisting huge potential methane gas in coals.However, petroleum exploration data throughout Indonesia suggest that increasing coal rank occurs rapidly with depth in many basins and that gas kicks are almost common associated with some coal seams below 200 m depth. In addition, world CBM exploration now has shifted towards lower rank settings (i.e, vitrinite reflectance between 0.3% and 0.6% Ro). In Indonesia, thick coals generally are found at greater depth, higher in rank and therefore are expected to be more productive (Saghafi and Hadiyanto, 2000).LEMIGAS is currently conducting a drilling program to study the feasibility of CBM production in South Sumatra. The domain of the work is in the Muaraenim Formation (Upper – Middle Palembang). The coal sequences were deposited during Late Miocene. We believe that a big effort is extremely essential to establish the reserve and economic potential of CBM in South Sumatra to later extent to Indonesia.

Technical and Economical Comparison of Supplying Energy from Combined Solar-Wind Power Plants in Lieu of Natural Gas Transmission Lines

Technical and Economical Comparison of Supplying Energy from Combined Solar-Wind Power Plants in Lieu of Natural Gas Transmission Lines

Investigation of Operational Scenarios to Mitigate CO2 Emission and Natural Gas Consumption in City Gate Stations (CGSs)

City gate stations (CGSs) are the main pressure reduction stations of natural gas (NG) transmission lines where enormous decrease of NG pressure results in significant temperature drop. Therefore, high pressure gas is preheated by means of NG fuel water bath heaters (WBHs) to prevent downstream hydrate formation. In this research, the effect of different operational scenarios was investigated by means of process simulation to enhance the combustion efficiency of WBHs which consequently causes lower CO2 emission into the atmosphere. In this regard, WBH of Minudasht CGS in the north of Iran with nominal capacity of 30,000 m3/h was considered as a case study and process enhancement was carried out with the goal of lower CO2 emission and the NG fuel consumption. On the basis of obtained results, it was demonstrated that the NG preheating and air preheating by means of energy of hot stack gases are the most effective scenarios which can result in around 65 and 50 tons lower CO2 emission, respectively. In addition, these scenarios have the merit of saving more than 33,000 and 25,000 m3 lower NG fuel consumption annually, respectively.

Prognosis of access to biomass residue resources in rural areas to provide energy for villagers

The potential evaluation of available biowaste was carried out for 95 villages of Gorgan in this study. The resources studied were wastes resulting from agricultural activities, including farming, horticulture, and livestock, as well as rural waste and wastewater. A coefficient was used to access the resources by filling a questionnaire, interviewing with experts and the use of the fuzzy analytic hierarchy process in order to have a theoretical estimation of resources closer to reality. This coefficient was determined based on the five factors including the suitability of warehousing, ease of transportation, quality of collection mechanism, access to production areas and no collection losses. Then, the information was geo-referenced in geographic information system. It was found that the total potential of the villages was 1,191,022 GJ, most of which were related to agricultural (9,87,986 GJ) and horticulture (94,416 GJ) waste, respectively. Regarding the per capita waste generation and the limiting factor of distance from natural gas transmission lines, southern parts of the province could be among the priority villages for biofuels development.

The Potential Impact Radius of a Natural Gas Transmission Line and Real Estate Valuations: A Behavioral Analysis

This study intended to address the question, “How would a purchase price be impacted if a seller provided buyers a notice that the residential property that has been listed for sale is located within a Potential Impact Radius (PIR) of a natural gas transmission line?” Does the notice of the location affect the purchase value a buyer is willing to offer for a residential property? Does the perceived risk associated with PIR affect the amount a potential buyer would offer? To address these questions, a Qualtrics survey that included three video tour treatments of a residential property was sent to three groups. A control group was presented a video tour without any residential disclosure notice. A second group was presented a video tour with an audible notice that the residence is located within 500 feet of a natural gas transmission line. A third group was presented a video tour with an audible notice that the residence is located within the potential impact radius (PIR) of a natural gas transmission line. Each respondent was asked to state a fair offer value for the residential property shown in their respective video. No statistically significant difference was found in the fair offer value mean between the control group and the group with notice the residence is located within 500 feet of a natural gas transmission line was found. No statistically significant difference was found in the fair market value between the group with notice the residence is located within 500 feet of a natural gas transmission line and the group with notice the residence is located within the potential impact radius (PIR) of a natural gas transmission line was found. A statistical significance was found where the control group was compared to the group with notice the residence is located within the potential impact radius (PIR).

An experimental study on the effects of various drill types on drilling performance of GFRP composite pipes and damage formation

Drilling is the most commonly used machining operation among others for assembly applications. The necessity of this operation has come to the forefront in composite materials that are becoming widespread nowadays. In this study, drilling performance of glass fiber reinforced plastic (GFRP) composite pipes used in many sectors such as natural gas transmission lines, pressurized sewer lines, industrial waste transmission, defense industry, and construction industry was investigated. The GFRP pipe was produced by filament winding method with a winding angle of ±55°. Different drill types (conventional twist drill, brad and spur drill, and brad center drill) with a drill diameter of 4 mm were utilized for drilling the pipe and the effect of drill type on the drilling performance was investigated. Drilling tests were performed at a constant 5000 rpm spindle speed and six different feed rate parameters (25, 75, 125, 175, 225, and 275 mm/min). Thrust forces generated during drilling were recorded and after the drilling operations, hole exit surface damage, and borehole surface damage were examined by a digital microscope and scanning electron microscope (SEM). Results showed that the brad center drill produced lower thrust forces while the twist drill generated higher thrust forces. The severity of damages could vary depending on the tool geometry and feed rate. Especially, at lower feed rates, conventional twist drill results with increased delamination and uncut fibers as compared with other drills. The brad center drill presents better performance since it generates fewer damages. Also, it is observed that these damages formed in the winding angle direction (orientation).

Advanced Electrochemical Sensors for Monitoring Relative Humidity and Internal Corrosion Rates of Natural Gas Transmission Pipelines Containing H2s

Monitoring the internal corrosion of natural gas transmission lines is required for safe management of natural gas infrastructures. Internal corrosion programs can be strengthened by real-time monitoring of key risk factors such as relative humidity and corrosion rates of the pipeline material. We have developed a membrane-based electrochemical sensor, which functions in gaseous environments, to provide this real-time monitoring capability. The design is based on the sensitivity of the membrane’s conductivity to gaseous water content. We match relative humidity curves to 4-electrode, electrochemical impedance spectroscopy results, and use 3-electrode, linear polarization resistance tests to calculate corrosion rates. Due to the membrane’s atypical current pathways, precise estimation of the sensor’s cell constant was required to interpret the impedance results into relative humidity. We utilize finite-element analysis to obtain our cell constant (14.84 cm-1), and the resulting membrane conductivity values were in good agreement with published data. The sensor was tested in H2S environments to gauge how these results may change with acidic gases that may be present in the natural gas stream.

Electrochemical impedance spectroscopy and finite element analysis modeling of a 4-electrode humidity sensor for natural gas transportation pipelines.

Reliable corrosion monitoring of natural gas transmission lines is a major tool providing a foundation for safe management of natural gas infrastructures. Through the development of membrane-based electrochemical sensors which are able to function in low-conductivity gas environments, corrosion monitoring practices can be further strengthened by real-time monitoring of key risk factors such as relative humidity and corrosion rates of corrodible structures. In this work, we demonstrate and validate how a 4-electrode conductivity sensor can provide a means to monitor relative humidity in gases via electrochemical impedance spectroscopy through finite element analysis (FEA). For a relative humidity range of 5%-55%, the impedance response varied from 1 kΩ to 66 kΩ, showing a high sensitivity for gas humidity. To confirm that the measured impedance values reliably interpreted relative humidity, it was found that precise estimation of the sensor's cell constant was needed. FEA was used to assess how the cell constant depended on the electrode geometry, membrane geometry, and electrode placement within the sensor. Through this approach, assumptions about the characteristic area and length were validated using electrolyte equipotential and current density vector mapping. This reduced possible cell constant uncertainties by 70%. With a cell constant of 14.84 cm-1, obtained via FEA, membrane conductivity values were in good agreement with published data.

Experimental and statistical analysis of low velocity impact response of filament wound composite pipes

Abstract Nowadays, filament wound composite pipes (GRP) are used as a structural element in many applications such as natural gas and oil transmission lines, and portable bridge constructions for military purposes. GRP pipes can expose to impact loading from various causes. This loading can cause an invisible level of damage. Thus, the detection and evaluation of such damages are of great importance. In this study, the low velocity impact response of (±55°)3 filament wound E-glass/epoxy composite pipes has been studied. The pipes have been subjected to drop weight impact loading with various impact energies. The force-time and force-displacement relations have been examined. The impact damage formation was also evaluated. It is concluded that the damage development in the pipes is controlled by displacement trough radial direction. The obtained results were evaluated statistically by means of Weibull approach. Microscopy analysis of impacted region revealed that debonding, radial cracks, transfer cracks and delamination damage modes are the main observed damage modes.

Corrosion Protection of Internal Surface of Natural Gas Transmission Line By Metallic Coating

Natural gas transmission pipelines are a known to leak and thus release methane which is a greenhouse gas (GHG). There are several mechanisms for these emissions, including venting of lines, mechanical damage, and corrosion failure. With the projected pipeline life being described as “virtually forever”, slow corrosive attack can be an issue. The corrosive failure can be by either the exterior or interior attack. While there are practices in place to protect the exterior of the pipelines, including organic coatings and impressed cathodic protection, these techniques are not practical for the pipe’s interior. While dry natural gas is considered non-corrosive, the maintenance/inspect process of pigging of pipelines typicality results in black corrosion deposits being removed. These corrosion deposits are most likely a result of inadvertent water reacting with residual carbon dioxide (CO2) forming carbonic acid and attacking the pipeline, particularly wherever this water pools. This research examined the use of sacrificial coatings on the interior of natural gas pipelines to protect the pipeline from corrosion. These tests simulated the case where trapped water is in the bottom of the pipeline. A typical natural gas pipeline can have 100 bar of pressure. The gas stream can have 3 to 4 vol % CO2. This can result in a CO2 partial pressure of 3 to 4 bars. NACE SP0106 says that CO2 at a partial pressure of greater than 2.1 bar in the presence of water is usually corrosive. Compression of the gas, which occurs every 40 to 100 miles, heats the gas which will accelerate the corrosion rate. The work examined the corrosion of an API 5L grade X65 steel in a test, 3 ½ wt. pct. NaCl solution with a 3.1 bar pressure of CO2 at 40 °C. Results of the corrosion rate of the bare steel were compared with that of several sacrificial metals, including Al and Zn. The corrosion rate of the steel coupled to sacrificial metals was measure for both parts of the couple.

Low velocity impact response of prestressed functionally graded hybrid pipes

Abstract Filament wound hybrid composite pipes are frequently used for the transmission of high pressured chemical fluids, disposal of industrial wastes, oil and natural gas transmission lines. In this study, low velocity impact behavior of the glass/carbon functionally graded filament wound composite pipes with ±55° winding angle was experimentally investigated. The hybrid composite pipes were graded with a fixed layer configuration from inside to outside as glass-glass/glass-carbon/carbon-glass/carbon-carbon. The functionally graded hybrid pipes were subjected to different internal pressure values (4, 16 and 32 bar), and impact response and energy absorption capacity of the hybrid composite pipes were investigated by using weight drop test method with impact energies of 5, 10, 15 and 20 J. The impact force and displacement versus interaction time were measured. The impulsive force, energy absorption capability, and damage formation were also investigated. Delamination, radial and surface matrix crack formations were observed as the main failure mechanisms at the outer surface of the hybrid pipes. Moreover, the effect of impact damage decreased with the increasing internal pressure of the pre-stressed hybrid composite pipes. The impact damaged composite pipes were subsequently subjected to burst tests according to ASTM D1599-99 standards to calculate burst strengths of the damaged composite pipes. The hybrid composite pipes subjected to 32 bar internal pressure before impact loading were exhibited highest burst strengths for the same impact energy levels.

Macroscopic Observations of Catastrophic Gas Hydrate Growth during Pipeline Operating Conditions with or without a Kinetic Hydrate Inhibitor

This paper presents the macroscopic observation of catastrophic gas hydrate growth during a shut-in, cold start-up and flowing conditions, simulating a natural gas transmission line operation. All experiments are conducted with a fixed simulated natural gas composition to form structure II gas hydrate with 11 K subcooling in the isochoric rocking cells. In order to simulate inhibited test systems, a formulated copolymer of vinylpyrolidone and vinylcaprolactam (PVP/PVCap) is included in some of the cells studied. Detailed macroscopic images and interpretation of pressure (P) and temperature (T) data are used to present our findings. It is found that production profiles such as different shut-in time and the mechanism of mass transfer of water from the bulk water phase to gas hydrate phase influence the gas hydrate growth in distinctive ways. Moreover, the capillary force in the gas hydrate structure may provide a greater driving force to promote gas hydrate growth than the diffusion rate of gases into the ...

Removal of Monoethylene Glycol from Gas Field Wastewater Using Aspergillus tubingensis and a New Bioreactor

Monoethylene glycol (MEG) is used in the oil and gas industry to prevent freezing along well-to-refinery natural-gas transmission lines. Once the gas reaches the refinery, the MEG is then separated from the gas. In this process MEG is introduced to the refinery wastewater, making it extremely polluted and hazardous to the aquatic environment. Therefore, it is important to remove this substance from refinery wastewaters. This study examined the use of a microorganism in a glass reactor to remove MEG from wastewater generated at South Pars Gas Field Phase 4, Bushehr, Iran. A novel reactor satisfying the experimental conditions was built. The microorganism Aspergillus tubingensis was isolated from wastewater containing MEG and identified using a polymerized chain reaction buffer. The microorganism was fixed on a packed bed and transported to the glass reactor. Sampling and measurements of chemical oxygen demand (COD), pH values, and MEG concentration were performed at different periods. After 240 h, a 65 % decrease in COD was achieved and MEG concentration was reduced by more than 40 %.

Optimization problems in natural gas transportation systems: A state-of-the-art review

Abstract This paper provides a review on the most relevant research works conducted to solve natural gas transportation problems via pipeline systems. The literature reveals three major groups of gas pipeline systems, namely gathering, transmission, and distribution systems. In this work, we aim at presenting a detailed discussion of the efforts made in optimizing natural gas transmission lines. There is certainly a vast amount of research done over the past few years on many decision-making problems in the natural gas industry and, specifically, in pipeline network optimization. In this work, we present a state-of-the-art survey focusing on specific categories that include short-term basis storage (line-packing problems), gas quality satisfaction (pooling problems), and compressor station modeling (fuel cost minimization problems). We discuss both steady-state and transient optimization models highlighting the modeling aspects and the most relevant solution approaches known to date. Although the literature on natural gas transmission system problems is quite extensive, this is, to the best of our knowledge, the first comprehensive review or survey covering this specific research area on natural gas transmission from an operations research perspective. The paper includes a discussion of the most important and promising research areas in this field. Hence, this paper can serve as a useful tool to gain insight into the evolution of the many real-life applications and most recent advances in solution methodologies arising from this exciting and challenging research area of decision-making problems.

Experimental Studies of Solubility of Elemental Sulfur in Methane at 363.15 K for Pressure Ranging from (4 to 25) MPa

In recent years, many problems of elemental sulfur deposits in natural gas transmission line systems have been noted. These problems occur very often immediately downstream of a pressure reduction facility. To prevent the apparition of solid sulfur deposits causing security and maintenance problems it is imperative to determine sulfur solubility in natural gas at pressures and temperatures corresponding to transport conditions. In a previous work (Serin et al. J. Supercrit. Fluids2010, 53, 12–16), an original experimental apparatus was designed, and experimental saturation values of carbon dioxide in sulfur were obtained. The protocol principle is schematically divided into three steps: saturation, trapping, and quantification. In this work, experimental sulfur solubility in methane was measured and compared to available studies at 363.15 K in the pressure range from (4 to 25) MPa. This paper presents these measurements and the improvements of the trapping and quantification steps that have been made to g...

Mathematical Modeling Of Corrosion Phenomenon In Pipelines

The annual cost of corrosion worldwide is over 3% of the world’s GDP. There are hundreds of thousands of kilometers of pipelines in various sectors of industry, which include many uncoated pipelines in chemical manufacturing plants, interstate natural gas transmission lines, and offshore oil-and-gas production pipelines. Mathematical modeling is richly endowed with many analytic computational techniques for analyzing real life situations. This paper reviewed that the predictive models on corrosion rate for natural gas pipeline. These models were selected based on the thermodynamic properties of the fluid and the developed rate is plotted against various operating conditions.

Experimental studies of solubility of elemental sulphur in supercritical carbon dioxide

In recent years, more and more problems of elemental sulphur deposits in natural gas transmission line systems have been reported. Available experimental data on the solubility of sulphur in gases are in too high ranges of temperature, pressure and hydrogen sulphide amount compared to the transport conditions of natural gas. An original experimental apparatus, designed from the study of available works on this subject, is presented and allows the measurement of sulphur solubility. An equilibrium cell establishes the solid–gas equilibrium in conditions of natural gas transportation. To measure the amount of sulphur contained in a known volume of gas, a sample of saturated gas is withdrawn from the equilibrium cell by the way of a flash and pass through a trapping solution. Gaseous elemental sulphur is reactively absorbed into a trapping mixture. Gas chromatography (GC) allows an indirect quantification of sulphur. Experimental isotherm data of sulphur solubility in supercritical carbon dioxide are presented and compared to available studies.

Elemental sulphur deposition in natural gas transmission and distribution networks

Deposition of elemental sulphur in natural gas transmission line systems has been reported on only in recent times. The most common location is immediately downstream of a point of significant pressure reduction. A necessary step to eliminate solid sulphur deposition is to understand the deposit mechanism. Two mechanisms appear possible: condensate formation and desublimation of sulphur vapours. To study the plausible paths of solid sulphur formation, we established a thermodynamic model. The constitutive equations are classically the chemical and physical equilibriums, partial mass balances and energy balance. We chose the Peng Robinson equation of state to describe the phase behaviour. Mixing rules are conventional: quadratic for a and linear for b with one binary interaction coefficient. Desublimation seems to be the most plausible mechanism to explain the solid sulphur formation. Pressure reduction implies temperature reduction, which reinforces solid formation. A solution to minimize the solid sulphur deposition seems to be heating the gas stream immediately before pressure reduction.