Autogenerative high pressure digestion: anaerobic digestion and biogas upgrading in a single step reactor system

2011 ◽  
Vol 64 (3) ◽  
pp. 647-653 ◽  
Author(s):  
R. E. F. Lindeboom ◽  
F. G. Fermoso ◽  
J. Weijma ◽  
K. Zagt ◽  
J. B. van Lier
Keyword(s):  
High Pressure ◽  
Anaerobic Digestion ◽  
Natural Gas ◽  
Ambient Pressure ◽  
Single Step ◽  
Reactor System ◽  
Dew Point ◽  
Bulk Liquid ◽  
Atmospheric Conditions ◽  
Biogas Upgrading

Conventional anaerobic digestion is a widely applied technology to produce biogas from organic wastes and residues. The biogas calorific value depends on the CH4 content which generally ranges between 55 and 65%. Biogas upgrading to so-called ‘green gas’, with natural gas quality, generally proceeds with add-on technologies, applicable only for biogas flows >100 m3/h. In the concept of autogenerative high pressure digestion (AHPD), methanogenic biomass builds up pressure inside the reactor. Since CO2 has a higher solubility than CH4, it will proportion more to the liquid phase at higher pressures. Therefore, AHPD biogas is characterised by a high CH4 content, reaching equilibrium values between 90 and 95% at a pressure of 3–90 bar. In addition, also H2S and NH3 are theoretically more soluble in the bulk liquid than CO2. Moreover, the water content of the already compressed biogas is calculated to have a dew point <−10 °C. Ideally, high-quality biogas can be directly used for electricity and heat generation, or injected in a local natural gas distribution net. In the present study, using sodium acetate as substrate and anaerobic granular sludge as inoculum, batch-fed reactors showed a pressure increase up to 90 bars, the maximum allowable value for our used reactors. However, the specific methanogenic activity (SMA) of the sludge decreased on average by 30% compared to digestion at ambient pressure (1 bar). Other results show no effect of pressure exposure on the SMA assessed under atmospheric conditions. These first results show that the proposed AHPD process is a highly promising technology for anaerobic digestion and biogas upgrading in a single step reactor system.

scholarly journals Innovative ex-situ biological biogas upgrading using immobilized biomethanation bioreactor (IBBR)

2020 ◽  
Vol 81 (6) ◽  
pp. 1319-1328 ◽  
Author(s):  
Katie Baransi-Karkaby ◽  
Mahdi Hassanin ◽  
Sharihan Muhsein ◽  
Nedal Massalha ◽  
Isam Sabbah
Keyword(s):  
Anaerobic Digestion ◽  
Natural Gas ◽  
Production Rate ◽  
Organic Waste ◽  
Consumption Rate ◽  
Energy Resource ◽  
Hydrogen Gas ◽  
Ex Situ ◽  
Biogas Upgrading ◽  
Immobilized Microorganisms

Abstract Biogas, which typically consists of about 50–70% of methane gas, is produced by anaerobic digestion of organic waste and wastewater. Biogas is considered an important energy resource with much potential; however, its application is low due to its low quality. In this regard, upgrading it to natural gas quality (above 90% methane) will broaden its application. In this research, a novel ex-situ immobilized biomethanation bioreactor (IBBR) was developed for biologically upgrading biogas by reducing CO2 to CH4 using hydrogen gas as an electron donor. The developed process is based on immobilized microorganisms within a polymeric matrix enabling the application of high recirculation to increase the hydrogen bioavailability. This generates an increase in the consumption rate of hydrogen and the production rate of methane. This process was successfully demonstrated at laboratory-scale system, where the developed process led to a production of 80–89% methane with consumption of more than 93% of the fed hydrogen. However, a lower methane content was achieved in the bench-scale system, likely as a result of lower hydrogen consumption (63–90%). To conclude, the IBBRs show promising results with a potential for simple and effective biogas upgrading.

Analysis of the Problem of Natural Gas Waterlogging

2020 ◽  
Vol 7 (4) ◽  
pp. 17-28
Author(s):  
Maciej Kotuła1 ◽  
◽  
Aleksander Szkarowski1 ◽  
Aleksandr Chernykh2 ◽  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Physicochemical Parameters ◽  
Unknown Origin ◽  
Atmospheric Conditions ◽  
Gas Industry ◽  
Legal Provisions ◽  
Computer Calculations ◽  
Moisture Condensation ◽  
Safe Transport

The domestic gas industry has been set an ambitious goal in the form of a state programme for extensive gasification of Polish cities and towns. This provides for transition of the municipal thermal energy and of the municipal economy to natural gas. Ensuring of reliable and safe transport of the gaseous fuel is also a part of this programme. The article discusses the problems of transporting of the nitrogen-rich natural gas from the local mines, related to water of unknown origin appearing in it. The events that can confirm that there is a possibility of moisture condensation from the gas and its migration deep into the distribution network have been analysed. The actual level of moisture in the natural gas, which is already directly supplied to the consumers, has been experimentally tested. It has been proved by the computer calculations that in the conditions of high pressure in the network, there is a possibility of such condensation, depending on the external atmospheric conditions and physicochemical parameters of the gas. It has been proposed to change the existing designing & construction legal provisions in order to protect the gas networks against water accumulating in them in a better way.

Flow Analysis of High Pressure Catalytic Combustor for Gas Turbine

1995 ◽  
Author(s):  
Y. Tsujikawa ◽  
S. Fujii ◽  
H. Sadamori ◽  
S. Ito ◽  
S. Katsura
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Flow Analysis ◽  
Methane Combustion ◽  
Single Step ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Gas Temperature ◽  
Radial Convection

The objective of this paper is modeling the mechanism of high temperature catalytic oxidation of natural gas, or methane. The model is two-dimensional steady-state, and includes axial and radial convection and diffusion of mass, momentum and energy, as well as homogeneous (gas phase) and heterogeneous (gas-surface) single step irreversible chemical reactions within a catalyst channel. Experimental investigations were also made of natural gas, or methane combustion in the presence of Mn-substituted hexaaluminate catalysts. Axial profiles of catalyst wall temperature, and gas temperature and gas composition for a range of gas turbine combustor operating conditions have been obtained for comparison with and development of a computer model of catalytic combustion. Numerical calculation results for low pressure agree well with experimental data. The calculations have been extended for high pressure (10 atms) operating conditions of gas turbine.

Spark-Ignition and Combustion Characteristics of High-Pressure Hydrogen and Natural-Gas Intermittent Jets

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Ali Mohammadi ◽  
Masahiro Shioji ◽  
Yuki Matsui ◽  
Rintaro Kajiwara
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Ambient Pressure ◽  
Direct Injection ◽  
Injection Pressure ◽  
Spark Ignition ◽  
Constant Volume Combustion Chamber ◽  
Si Engines ◽  
Ignition And Combustion ◽  
Combustion Processes

Recently, an in-cylinder injection method has been considered for the improvement of thermal efficiency in natural-gas and hydrogen spark-ignition (SI) engines. However, the SI and combustion processes of gaseous jets are not well understood. The present study aims to provide fundamental data for the development of direct-injection SI gas engines. The ignition, combustion, and flame behavior of high-pressure and intermittent hydrogen and natural-gas jets in a constant volume combustion chamber were investigated. The effects of injection pressure, nozzle size, ambient pressure, and spark location were also investigated for various spark timings and equivalence ratios.

Offshore Natural Gas Conditioning and Recovery of Methanol as Hydrate Inhibitor with Supersonic Separators: Increasing Energy Efficiency with Lower CO2 Emissions

2019 ◽  
Vol 965 ◽  
pp. 97-105
Author(s):  
Alexandre Mendonça Teixeira ◽  
Lara de Oliveira Arinelli ◽  
José Luiz de Medeiros ◽  
Ofélia de Queiroz Fernandes Araújo
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Power Consumption ◽  
Gas Phase ◽  
Aqueous Phase ◽  
Hydrate Formation ◽  
Dew Point ◽  
External Temperature ◽  
Thermodynamic Conditions ◽  
Commercial Value

The oil and gas industry represents an important contributor to CO2 emissions as offshore platforms are power intensive for producing, processing and transporting hydrocarbons. In offshore rigs CO2 emissions mainly come from on-site gas-fired power generation for heat and electricity production. The accumulation of atmospheric CO2 is one of the main causes of the planetary greenhouse effect, thus CO2 emissions should be minimized. To achieve that, more energy efficient processes for natural gas (NG) conditioning are needed in order to minimize platform power consumption and thus lowering the associated generation of CO2. In addition, in offshore scenarios gas-hydrate obstructions are a major concern in flow assurance strategies, since thermodynamic conditions favoring hydrate formation are present, such as high pressure, low external temperature and gas contact with free water. To avoid hydrate issues, hydrate inhibition is carried out by the injection of a thermodynamic hydrate inhibitor (THI) in well-heads such that it flows along with production fluids, thus removing the thermodynamic conditions for hydrate formation and ensuring unimpeded flow. Therefore, the three-phase high-pressure separator (HPS) is fed with production fluids, where the HPS splits the feed into: (i) an upper gas phase, (ii) hydrocarbon condensate, and (iii) a bottom aqueous phase. The gas phase goes to NG conditioning for hydrocarbon dew point adjustment (HCDPA) and water dew point adjustment (WDPA) so as to make NG exportable. The hydrocarbon condensate (if present) is collected for stabilization and the bottom aqueous phase consisting of water, salts and THI is sent to a THI recovery unit (THI-RU) for THI re-concentration and reinjection. In conventional plants, WDPA and HCDPA are done by glycol absorption and Joule-Thomson expansion respectively. Moreover, the HPS gas carries some THI such as methanol that is lost in the processing. This work analyses a new process – SS-THI-Recovery – where HPS gas feeds a supersonic separator (SS) with injected water and compares it to the conventional processing. As a result, SS ejects a cold two-phase condensate with almost all water, THI and C3+ hydrocarbons, discharging exportable NG with enough HCDPA and WDPA grades, while the condensate gives aqueous THI returned to the THI-RU and LPG with high commercial value. Thus, SS-THI-Recovery not only avoids THI losses as well as exports NG and LPG. Both conventional gas plant and SS-THI-Recovery alternative coupled to THI-RU were simulated in HYSYS 8.8 for a given NG field and targeting the same product specifications. SS-THI-Recovery presented lower power consumption and thus less associated CO2 emissions, while potentially increasing the gas plant profitability, as THI losses are significantly reduced and higher flow rate of LPG with higher commercial value is produced in comparison with the conventional alternative. Hence, the higher efficiency of SS-THI-recovery makes it not only more environmentally friendly with lower CO2 emissions, but also a potential alternative for improving process economics and thus providing an economic leverage that could justify investments in carbon capture technologies, contributing to avoid CO2 emissions even more with cleaner NG and LPG production.

FLOX® Combustion at High Pressure With Different Fuel Compositions

2007 ◽  
Author(s):  
Rainer Lu¨ckerath ◽  
Wolfgang Meier ◽  
Manfred Aigner
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Flue Gas ◽  
Operating Conditions ◽  
Atmospheric Conditions ◽  
Relative Temperature ◽  
Planar Laser ◽  
Gas Recirculation ◽  
First Time

In Flameless Oxidation (FLOX®) the combustion is distributed over a large volume by a high internal flue gas recirculation. This technology has been successfully used for many years in technical furnaces under atmospheric conditions with very low NOx emissions. In the work presented here, FLOX® combustion was for the first time investigated at high pressure in order to assess its applicability for gas turbine combustors. A FLOX® burner was equipped with a combustion chamber with quartz windows and installed into a high pressure test rig with optical access. The burner was operated under typical gas turbine conditions at pressure of 20 bar with thermal powers up to 475 kW. Natural gas as well as mixtures of natural gas and H2 were used as fuel. The NOx and CO emissions were recorded for the different operating conditions. OH* chemiluminescence imaging and planar laser-induced fluorescence of OH were applied in order to characterize the flame zone and the relative temperature distributions. The combustion behaviour was investigated as a function of equivalence ratio and fuel composition, and the influence of the gas inlet velocity on mixing and emissions was studied. For various operating conditions the lean extinction limits were determined.

Optimized Ejector-Diffuser Design Procedure for Natural Gas Vapor Recovery

1983 ◽  
Vol 105 (3) ◽  
pp. 388-393 ◽  
Author(s):  
J. C. Dutton ◽  
B. F. Carroll
Keyword(s):  
High Pressure ◽  
Mach Number ◽  
Natural Gas ◽  
Compression Ratio ◽  
Ambient Pressure ◽  
Design Procedure ◽  
Area Ratio ◽  
Optimized Design ◽  
Storage Tanks ◽  
Oil Storage

A procedure for designing optimized ejector-diffuser systems for recovering natural gas vapor from oil storage tanks is presented. The system utilizes high pressure gas from the separator to entrain the ambient pressure gas from the tanks and then pumps the mixture to the sales line. The analysis predicts the minimum separator pressure and the optimum nozzle Mach number and ejector area ratio required to accomplish this task. The results of a parametric study suggest that this system is feasible and that the higher the required ejector compression ratio the more critical is the use of an optimized design.

FLOX ® Combustion at High Pressure With Different Fuel Compositions

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Rainer Lückerath ◽  
Wolfgang Meier ◽  
Manfred Aigner
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Flue Gas ◽  
Operating Conditions ◽  
Atmospheric Conditions ◽  
Relative Temperature ◽  
Planar Laser ◽  
Gas Recirculation ◽  
First Time

In flameless oxidation (FLOX®) the combustion is distributed over a large volume by a high internal flue gas recirculation. This technology has been successfully used for many years in technical furnaces under atmospheric conditions with very low NOx emissions. In the work presented here, FLOX® combustion was for the first time investigated at high pressure in order to assess its applicability for gas turbine combustors. A FLOX® burner was equipped with a combustion chamber with quartz windows and installed into a high pressure test rig with optical access. The burner was operated under typical gas turbine conditions at a pressure of 20bar with thermal powers up to 475kW. Natural gas, as well as mixtures of natural gas and H2 were used as fuel. The NOx and CO emissions were recorded for the different operating conditions. OH* chemiluminescence imaging and planar laser-induced fluorescence of OH were applied in order to characterize the flame zone and the relative temperature distributions. The combustion behavior was investigated as a function of equivalence ratio and fuel composition, and the influence of the gas inlet velocity on mixing and emissions was studied. For various operating conditions, the lean extinction limits were determined.

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