In line with the low-carbon strategy, the EU is expected to be climate-neutral by 2050, which would require a significant increase in renewable energy production. Produced biogas is directly used to ...produce electricity and heat, or it can be upgraded to reach the “renewable natural gas”, i.e., biomethane. This paper reviews the applied production technology and current state of biogas and biomethane production in Europe. Germany, UK, Italy and France are the leaders in biogas production in Europe. Biogas from AD processes is most represented in total biogas production (84%). Germany is deserving for the majority (52%) of AD biogas in the EU, while landfill gas production is well represented in the UK (43%). Biogas from sewage sludge is poorly presented by less than 5% in total biogas quantities produced in the EU. Biomethane facilities will reach a production of 32 TWh in 2020 in Europe. There are currently 18 countries producing biomethane (Germany and France with highest share). Most of the European plants use agricultural substrate (28%), while the second position refers to energy crop feedstock (25%). Sewage sludge facilities participate with 14% in the EU, mostly applied in Sweden. Membrane separation is the most used upgrading technology, applied at around 35% of biomethane plants. High energy prices today, and even higher in the future, give space for the wider acceptance of biomethane use.
Recently, due to the corrosion problem in the petroleum industry and the usage of commercial corrosion inhibitors, which, when released untreated into the environment, are considered to be ...environmentally unfriendly, green corrosion inhibitors are being researched. In this paper, the results of dandelion-root-extract testing as a green corrosion inhibitor for carbon steel in simulated brine solution saturated with carbon dioxide (CO2) are shown. The extract’s inhibition efficiency in static and flow conditions was determined by using potentiodynamic polarization with Tafel extrapolation and electrochemical-impedance-spectroscopy methods. In static conditions, the extract was tested at different concentrations. A maximum inhibition efficiency of 98.37% in static conditions at an extract concentration of 12 mL/L and 82.80% in flow conditions at a concentration of 14 mL/L was achieved. Additionally, for the most efficient dandelion-root-extract concentration (12 mL/L), the biodegradability and toxicity were determined. A biodegradability of 0.96 and a toxicity of 2.38% was achieved. Based on the obtained results of the conducted laboratory measurements, it can be concluded that dandelion-root extract has significant potential in terms of its use as a green corrosion inhibitor for carbon steel in a CO2-saturated brine solution.
In this paper, preliminary studies of ten different plant extracts as potential corrosion inhibitors of carbon steel were examined. For each extract, the concentration range in which it shows ...anti-corrosion action was first determined, and then the most effective concentration was determined for each extract. The tests were performed in a brine solution saturated with CO2 at room temperature. The aim of this study was to isolate extracts with high effectiveness and subsequent electrochemical and surface methods to determine the mechanism of inhibitory action. For this purpose, potentiodynamic polarization was performed with Tafel extrapolation. Among all the tested extracts, lady’s mantle (92.17%) and dandelion root (95.07%) stood out with their effectiveness. Both tested extracts showed the behaviour of a mixed corrosion inhibitor with a dominant influence on the anode process.
Due to issues with the corrosion problem in the petroleum industry and the use of less ecologically acceptable corrosion inhibitors, great emphasis, within research on corrosion inhibitors, is now ...being put on green corrosion inhibitors (GCIs). In this study, Lady’s mantle flower extract (LMFE) has been observed as a plant-based GCI for carbon steel in a simulated COsub.2-saturated brine solution. The effectiveness of the inhibitor in static and flow conditions has been determined using potentiodynamic polarization with Tafel extrapolation and electrochemical impedance spectroscopy (EIS). In static conditions, the inhibitor has been tested at concentrations from 1 g/L to 5 g/L with an increment of 1 g/L per measurement, while, in dynamic (flow) conditions, the inhibitor has been tested at concentrations from 3 g/L to 6 g/L with an increment of 1 g/L per measurement. All measurements were performed at room temperature. EIS and potentiodynamic polarization methods showed that LMFE achieves maximum effectiveness in protecting carbon steel from corrosion when added at a concentration of 4 g/L in static conditions and at a concentration of 5 g/L in flow conditions. The test methods proved that the inhibitory effectiveness of LMFE is greater than 90% in both test conditions (static and flow). The inhibitor efficiency was attributed to the adsorption of LMFE on the carbon steel surface, which was demonstrated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A biodegradability of 0.96 and a toxicity of 19.34% for LMFE were determined. The conducted laboratory tests indicate that LMFE could be used as an effective corrosion inhibitor for COsub.2 carbon steel corrosion.
Due to issues with the corrosion problem in the petroleum industry and the use of less ecologically acceptable corrosion inhibitors, great emphasis, within research on corrosion inhibitors, is now ...being put on green corrosion inhibitors (GCIs). In this study, Lady’s mantle flower extract (LMFE) has been observed as a plant-based GCI for carbon steel in a simulated CO2-saturated brine solution. The effectiveness of the inhibitor in static and flow conditions has been determined using potentiodynamic polarization with Tafel extrapolation and electrochemical impedance spectroscopy (EIS). In static conditions, the inhibitor has been tested at concentrations from 1 g/L to 5 g/L with an increment of 1 g/L per measurement, while, in dynamic (flow) conditions, the inhibitor has been tested at concentrations from 3 g/L to 6 g/L with an increment of 1 g/L per measurement. All measurements were performed at room temperature. EIS and potentiodynamic polarization methods showed that LMFE achieves maximum effectiveness in protecting carbon steel from corrosion when added at a concentration of 4 g/L in static conditions and at a concentration of 5 g/L in flow conditions. The test methods proved that the inhibitory effectiveness of LMFE is greater than 90% in both test conditions (static and flow). The inhibitor efficiency was attributed to the adsorption of LMFE on the carbon steel surface, which was demonstrated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A biodegradability of 0.96 and a toxicity of 19.34% for LMFE were determined. The conducted laboratory tests indicate that LMFE could be used as an effective corrosion inhibitor for CO2 carbon steel corrosion.
Hydraulics play an important function in many oil field operations including drilling, completion, fracturing, acidizing, workover and production. The standard API methods for drilling fluid ...hydraulics assume either power law or Bingham plastic rheological model. These models and corresponding hydraulic calculations do provide a simple way for fair estimates of hydraulics for conventional vertical wells using simple drilling fluids, such as bentonite fluids. However, nowdays with many wells drilled deep, slim or horizontal using complex muds with unusual behaviour (such as tested MMH mud), it is necessary to use appropriate rheological model for mathematical modelling of fluid behaviour. Oil and gas reservoirs in Croatia have been under production for quite a while and the probability to discover new deposits of hydrocarbons is rather small. Therefore attempts have been made to maintain the gas and oil exploitation at the present level. One of possible ways to meet this target is re-entry wells drilling. The diameter of such wells in reservoir is smaller than 0,1524 m (6 in). Accurate modelling of annular pressure losses becomes therefore an important issue, particularly in cases where a small safety margin exists between optimal drilling parameters and wellbore stability, what is the case in re-entry wells. The objective of the paper is to show the influence of well geometry and accuracy of fluid rheological properties modelling to the distribution of pressure losses in a slimhole well. PUBLICATION ABSTRACT
High pressure pipelines are the most common way of natural gas transport from a gas field to a processing plant and further to consumers. In case when the distance between natural gas production and ...consumption regions is more than 4000 kilometers, and due to necessity of natural gas supply diversification, gas liquefaction and its transport by ships is being applied. The final choice of liquefaction process depends on the project variables, the development level of new or upgrading of already existing processes and available equipment. Current natural gas liquefaction processes and their usage in practice are shown in this paper (the paper is published in Croatian).
LIQUIFIED NATURAL GAS (LNG) CARRIERS Daniel Posavec; Katarina Simon; Matija Malnar
Rudarsko-geološko-naftni zbornik,
01/2010, Letnik:
22, Številka:
1
Journal Article
Odprti dostop
Modern liquefied natural gas carriers are double-bottom ships classified according to the type of LNG tank. The tanks are specially designed to store natural gas cooled to -161°C, the boiling point ...of methane. Since LNG is highly flammable, special care must be taken when designing and operating the ship. The development of LNG carriers has begun in the middle of the twentieth century. LNG carrier storage space has gradually grown to the current maximum of 260000 m3. There are more than 300 LNG carriers currently in operation (the paper is published in Croatian).
Enhanced oil recovery based on CO₂ injection is expected to increase recovery from Croatian oil fields. Large quantities of CO₂ are generated during hydrocarbon processing produced from gas and gas ...condensate fields situated in the north-western part of Croatia. First CO₂ injection project will be implemented on the Ivanić Oil Field. Numerical modelling based on Upper Miocene sandstone core samples testing results have shown the decrease of oil viscosity during CO₂ injection. Some of the characteristics of the testing samples are porosity 21.5–23.6 %, permeability 14–80 × 10⁻¹⁵ m² and initial water saturation 28–38.5 %. Water alternating foam (WAF) and water alternating gas (WAG) simulations have provided satisfactory results. The WAF injection process has provided better results, but due to the process sensitivity and costs WAG is recommended for future application. During the pilot project 16 × 10⁶ m³ CO₂ and 5 × 10⁴ m³ of water were injected. Additional amounts of hydrocarbons (4,440 m³ of oil and 2.26 × 10⁶ m³ of gas) were produced which confirmed injection of CO₂ as a successful tertiary oil recovery mechanism in Upper Miocene sandstone reservoirs in the Croatian part of the Pannonian Basin System.
Enhanced oil recovery based on CO sub(2) injection is expected to increase recovery from Croatian oil fields. Large quantities of CO sub(2) are generated during hydrocarbon processing produced from ...gas and gas condensate fields situated in the north-western part of Croatia. First CO sub(2) injection project will be implemented on the Ivanic Oil Field. Numerical modelling based on Upper Miocene sandstone core samples testing results have shown the decrease of oil viscosity during CO sub(2) injection. Some of the characteristics of the testing samples are porosity 21.5-23.6 %, permeability 14-80 10 super(-15) m super(2) and initial water saturation 28-38.5 %. Water alternating foam (WAF) and water alternating gas (WAG) simulations have provided satisfactory results. The WAF injection process has provided better results, but due to the process sensitivity and costs WAG is recommended for future application. During the pilot project 16 10 super(6) m super(3) CO sub(2) and 5 10 super(4) m super(3) of water were injected. Additional amounts of hydrocarbons (4,440 m super(3) of oil and 2.26 10 super(6) m super(3) of gas) were produced which confirmed injection of CO sub(2) as a successful tertiary oil recovery mechanism in Upper Miocene sandstone reservoirs in the Croatian part of the Pannonian Basin System.
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