High-quality Gas Research Articles

System development and analysis for producing high quality gas and activated sludge char

For energy and resource utilization of dried sewage sludge, an integrated system with in-line connection of pyrolysis gasifier, plasma reformer, and fixed bed adsorber was developed. The plasma reformer was set to improve producer gas yield by destructing tar released from the pyrolysis gasifier. The fixed bed adsorber filled with the sludge char produced from the pyrolysis gasifier was installed for adsorption of un-treated tar. The pyrolysis gasifier produced sludge char, tar and gas. The sludge char showed 98.1 m2/g of specific surface area and 63.49 A of mean pore size, which had a good distribution of micropore and mesopore with superior adsorption rate of light PAH tar. The concentrations of gravimetric tar and total light tar were 26.3 g/Nm3 and 10.9 g/Nm3, respectively. The analyzed light tar was in the order of benzene, naphthalene, benzonitrile, benzeneacetonitrile, anthracene and pyrene. Produced gas was composed of hydrogen, carbon monoxide, methane, and carbon dioxide. The plasma reformer displayed 83.2% of removal efficiency with 4.4 g/Nm3 of gravimetric tar at the outlet due to tar cracking and steam reforming reaction. The total amount of light tar was 1.3 g/Nm3. Among the reforming gas, the concentration of hydrogen, carbon monoxide, and methane was increased. Gravimetric tar at the outlet of the adsorber was 0.5 g/Nm3, which was 88.6% of removal efficiency. The total amount of light tar was 0.39 g/Nm3. Gas analysis results at the exit showed 50.5% H2, 21.9% CO, 10.5% CH4, 7.7% CO2 and 0.1% C2H2 with a higher heating value of 13,482 kJ/Nm3. Therefore, sewage sludge can be converted into energy and resource by pyrolysis and gasification since the producer gas and sludge char could be utilized in a heat engine and adsorption tower for tar removal, respectively.

Removal of high concentration CO 2 from natural gas at elevated pressure via absorption process in packed column

Carbon dioxide (CO 2) removal is an essential step in natural gas (NG) processing to provide high quality gas stream products and minimize operational difficulties. This preliminary study aims to investigate the removal of CO 2 at high concentration level from the mixture of CO 2-NG gas stream at elevated pressure via absorption process. This is to explore the possibility of exploring high CO 2 content natural gas reserves by treatment at offshore platform. A mixed amine solvent, Stonvent-II, was used for the absorption of approximately 75 vol% CO 2 in CO 2-NG stream at a pressure of 10 barg. The initial solvent temperature was varied in order to study the impact of initial temperature on the absorption performance. Preliminary study at temperatures of 35°C and 45°C indicates that Stonvent-II was able to perform almost 100% removal of CO 2 under both conditions. However, the CO 2 absorption effect took place faster when the initial liquid temperature was lower. This is because when the initial liquid temperature is high, the temperature increase in the packing bed caused by the reaction heat is high which impacts the efficiency of absorption negatively.

Development of Micromegas for neutrinoless double beta decay searches

The present paper is a summary of experimental tests performed with microbulk Micromegas for application in a neutrinoless double beta decay experiment based in a xenon TPC. No critical limitation related with high pressure has been detected for Micromegas, which has been tested up to 10 bar. No significant differences have been found between low energy X-rays and high energy alpha tracks regarding ionization yield and electronic transparency of Micromegas mesh. Using 5.5 MeV alphas in argon-isobutane mixtures, values as low as 1.8% FWHM have been obtained, with possible evidence that better resolutions are achievable. These results seems independent of pressure (probed up to 4.5 bar) or gas mixture (microbulks have run in xenon without quencher). The imperative necessity of high quality gas led to start on a new TPC and MPGD dedicated lab at Zaragoza.

Diffraction in low-energy electron scattering from DNA: Bridging gas-phase and solid-state theory

Using high-quality gas phase electron scattering calculations and multiple scattering theory, we attempt to gain insights on the radiation damage to DNA induced by secondary low-energy electrons in the condensed phase, and to bridge the existing gap with the gas phase theory and experiments. The origin of different resonant features (arising from single molecules or diffraction) is discussed and the calculations are compared to existing experiments in thin films.

Upgrading peat to gas and liquid fuels in supercritical water with catalysts

Peat was effectively upgraded into gas and liquid fuels by supercritical water treatment at 380–440°C with and without catalyst. Treatment of the peat without using catalyst at a temperature ranging from 350°C to 440°C generally led to 5–10wt% yield of water soluble oil (WSO), about 15wt% yield of heavy oil (HO), 20–27wt% yield of Gas and 20–30wt% yield of Char. As expected, the Gas yield increased and the yields of oils and Char generally decreased at a higher operation temperature. The optimal conditions for a greater HO yield appeared to be a lower residence time and a lower water-to-peat ratio (i.e., a higher initial biomass concentration). Among all the catalysts tested including 0.1M K2CO3, 0.1M FeSO4, 0.1M RuO2, and 0.1M and 1.0M Ca(OH)2, 0.1M Ca(OH)2 was found the most effective for enhancing the production of liquid oils of both HO and WSO. The presence of 1.0M Ca(OH)2 at 410°C produced extremely low CO2 yield, due to the adsorption reaction of CO2 over the Ca(OH)2 catalyst, and a fourfold increase in H2, resulting in a high quality gas product with a HHV of 27.7MJ/kg, as oppose to only 2.81MJ/kg for the gas product without catalyst. Among all the catalysts tested, RuO2 proved to be the best catalyst for upgrading peat to H2-rich gas products, and the formation of H2 attained as high as 2.44mmol/g with 0.1M RuO2 at 410°C, compared with 0.05mmol/g without catalyst. The HOs obtained from the SCW treatments, rich in phenolic compounds and fatty acids, possess much greater caloric values (with a HHV of >33–35MJ/kg) than the dried peat powder used (with a HHV of about 21MJ/kg).

Equipment for hydrogen absorption-desorption cycling characterization of hydride forming materials

Hydrogen storage materials suffer different degradation processes when they are cycled, forming and decomposing their associated hydride phases. In order to study these processes, we have designed and built an automated apparatus specifically developed for cycling samples of hydride forming materials by changing the external hydrogen pressure. Instead of the standard open configuration involving a high-pressure, high-quality gas bottle and a vacuum pump, the equipment uses another hydride forming material (in our case LaNi5) as a source and sink of hydrogen. The resulting closed-loop configuration eliminates hydrogen waste and ensures that extremely high purity gas is used during the whole experiment, thanks to the purifying properties of the selected hydride as source/sink. Hydrogen pressure is set by changing the source/sink temperature. Cycles can be performed as fast as one cycle every 5 min, a period comparable with typical good hydride forming material kinetics. An example of application of the apparatus is given for 1000 absorption/ desorption cycles on a Mm0.8Ca0.2Ni5 sample.

Uniform and high-quality submicrometer tubes of GaS layered crystals

GaS, group III–VI semiconductor compound, is known to possess a layered structure. In this letter, uniform and high-quality GaS submicrometer tubes have been synthesized via a simple high-temperature thermal reaction route. Each GaS tube is uniform in size, and has length up to tens of microns and outer diameter of ∼200–900nm; some of the tubes are partially filled with liquid metallic Ga “rods.” Photoluminescence spectrum reveals that the GaS tubes have two strong emission bands centered at ∼585 and ∼615nm. Possible reaction processes and a rolling-up growth mechanism of as-grown GaS tubes were briefly discussed.

The Importance of Comprehensive Gas Field Surveillance

Abstract Outline of Problem Gas field surveillance historically has not been given the same priority as oil field surveillance because of a couple of significant stumbling blocks: first, the apparent simplicity of gas reservoirs- at least upon initial examination; and, second, the historically low commodity prices of gas relative to oil. The presumption that gasfield surveillance was easily derived from the knowledge that, in most gas pools, single phase flow existed, leading to the assumption that "tank like" behaviour was occurring. However, on examination of hundreds of gas pools, my viewpoint on that matter has changed dramatically. Of course, today's commodity prices are also changing both the relative and absolute perceptions about the economic importance of gas. Initially, in the Western Canadian Sedimentary Basin (WCSB), industry encountered and dealt with very high quality gas resources, such as those found in Leduc reservoirs. These reservoirs had high permeability and were not compartmentalized; this naturally led to the "tank model" approach. These pools had behaviour as illustrated by Figure 1(a). In the last few years, we have moved from what I would term "Tier One" resources to lower quality ones, as shown in Figure 2. Indeed, a large portion of reservoirs do not exhibit that "tank like" behaviour shown in Figure 1(a); instead, there is often a fairly large pressure gradient across pools and non-tank like behaviour, such as that shown in Figure 1(b). This paper stresses the importance of comprehensive surveillance for those types of fields, using simple methods of production analysis and pressure diagnostic tools. There has been an explosion of research on using gas rate decline methods to characterize reservoirs with an effective permeability less than 0.1 mD (k < 0.1mD). However, the transient gas rate decline and practical analysis of such low permeability gas reservoirs are not the focus of this paper. This paper instead focuses on gas field surveillance for multi-well pools in which wells are in boundary dominated flow. The objectives of any gas surveillance program are relatively simple:What is the Original Gas in Place (OGIP)?;What is the current gas in place?;Where is the current gas in place located?;What is the permeability or capacity (kh) of the wells and pool?;What are the limiting considerations to gas recovery factor (low permeability, liquid lifting problems, low continuity, high back pressure, or water influx)?;What can be done to improve the rate of recovery and the recovery factor? and,Can this be done economically? In order to understand the above questions, we must relate the static model (geological/petrophysical) to the dynamic (production/ pressure data) one. Surveillance Methodology The following work flow has proven to be useful in determining the true potential of gas reservoirs:Examine the production profile of individual wells and the field. Examine the initial production rates (IP), interference effects, types of decline, and decline rates (production diagnostics);

Challenges of developing Carboniferous gas fields in the UK Southern North Sea

The Carboniferous, as one of the three major productive intervals in the UK Southern North Sea, has considerable future potential, particularly as national demand for gas exceeds production. Almost 3 × 10 12 SCF are under development in the southern Quad 44 area, more than 600 × 10 9 SCF reserves discovered await development and the potential for yet-to-find reserves is recognized. Most of the undeveloped assets have transferred ownership a number of times and only now are operators and partner groups going ahead with development. The subsurface, engineering and commercial challenges that face those operators are outlined. The Carboniferous reservoir sandstones are relatively thin and cannot be mapped directly using 3D seismic data. Because they are separated by non-reservoir shales and siltstones, understanding the three-dimensional distribution of these sandstones is critical to ensure optimal well placement, maximum exposure to the reservoir and, ultimately, recovery of gas. Trap definition and size depend upon accurate seismic time-to-depth conversion of a complex overburden. Halokinesis, lateral velocity variations, erosional unconformities and wedges of low velocity sediments all need to be addressed in order to generate the best time-to-depth conversion. Gas in Carboniferous reservoirs is richer in inert gases, CO 2 and N 2 , than is gas from the Rotliegendes fields. These two gases contribute to reducing its calorific and commercial value, necessitating blending with higher quality gas or the removal of the inert gases before acceptence for entry into onshore distribution networks. This relies on the ability, willingness and capacity of host facility operators to accept this gas through their infrastructure. Negotiations to allow blending and acceptance of lower calorific value gas, to no detriment to the user, and the removal of inert gases will result in continued development of the Carboniferous fields. It may also encourage further exploration of the Carboniferous once a market and an off-take route to that market are established.

Experimental Investigation of Biomass Waste, (Rice Straw, Cotton Stalk, and Pine Sawdust), Pyrolysis Characteristics

Several types of biomass wastes were pyrolyzed with an atmospheric pressure TGA apparatus and a self-made fixed-bed reactor. The weight-loss curve from TGA based on different reference samples and final product distribution as well as gas composition from the fixed-bed reactor are presented here. TGA results indicate that biomass pyrolysis can be identified as 3 phases, i.e., moisture evaporation, main devolatilization, and continuous devolatilization; the reference sample has a slight influence on the weight loss of the biomass sample; different biomass samples can lead to the same tread of its weight-loss curve, but a different amount of weight loss. Fixed-bed pyrolysis results show that producer gas is a very important product, up to 60 wt%, and H2 and CO account for more than 60 vol%. The producer gas is hereby thought of as a high quality gas source, with a heating value of 13,000–14,000 kJ/Nm3 and a low tar concentration.

Experimental Investigation of Biomass Waste, (Rice Straw, Cotton Stalk, and Pine Sawdust), Pyrolysis Characteristics

Several types of biomass wastes were pyrolyzed with an atmospheric pressure TGA apparatus and a self-made fixed-bed reactor. The weight-loss curve from TGA based on different reference samples and final product distribution as well as gas composition from the fixed-bed reactor are presented here. TGA results indicate that biomass pyrolysis can be identified as 3 phases, i.e., moisture evaporation, main devolatilization, and continuous devolatilization; the reference sample has a slight influence on the weight loss of the biomass sample; different biomass samples can lead to the same tread of its weight-loss curve, but a different amount of weight loss. Fixed-bed pyrolysis results show that producer gas is a very important product, up to 60 wt%, and H2 and CO account for more than 60 vol%. The producer gas is hereby thought of as a high quality gas source, with a heating value of 13,000–14,000 kJ/Nm3 and a low tar concentration.

Structure−Property Relationships for Poly(pyrrolone-imide) Gas Separation Membranes

Previous studies have examined polypyrrolone and polyimide membranes for gas separations. For the first time this study examines poly(pyrrolone-imide) copolymers for the O2/N2, CO2/CH4, and C3H6/C3H8 separation. Combining these two classes of polymers is designed to provide rigidity and desirable mechanical properties in addition to high-quality gas transport properties. Specifically, the copolymer 6FDA-TAB/DAM was studied while systematically varying the TAB/DAM ratio in order to quantitatively alter the structure of the polymer matrix. Most copolymers studied exhibited results near or above the “upper bound” for O2/N2, CO2/CH4, and C3H6/C3H8 separations. Surprisingly, a maximum in C3H6/C3H8 selectivity was found as a function of the TAB/DAM ratio, and this does not follow the trend expected based on previous literature data. A similar trend has also been observed in carbon molecular sieve materials with varying material structure. This demonstrates that certain materials may show excellent size selectiv...

Control factors and porosity evolution of high-quality sandstone reservoirs of Kela-2 gas field in Kuqa Depression

By using the integrated methods including sandbodies modelling of the outcrops, sedimentary facies of the cores and well logs of the drilled wells, and the reservoir correlation of interwells, it is thought that the sandstone reservoirs of Kela-2 gas field are a suit of high-quality natural gas reservoirs with great thickness, extensive and continuous distribution, high porosity and permeability, and a few barrier beds. Sedimentary facies and microfacies are the main factors controlling the reservoir distribution and interior heterogeneity. Based on a great deal of data of rock’s thin sections, porosity, permeability, and the parameters of capillary pressure, the reservoir diagenesis, controls, mechanism and evolution of pores have been studied. It is considered that compaction in the early stage and diagenetic dolomite and calcite cements have effect on the decline of reservoirs property. Now compaction is chiefly middle to weak. The better reservoirs have no or a few calcite cements. In the early of deep buried stage, there are still mainly remainder primary intergranular pores. The authigenic kaolinite of reservoirs is the production of the dissolution of feldspars and lithic fragments. The dissolution results in the partly modified and broadened secondary intergranular pores. In the late of deep buried stage, structure fissures and overpressure were in favor of improving and preservation of these pores.

Biomass conversion into fuel gas using circulating fluidised bed technology: the concept improvement and modelling discussion

Fuel gas production from biomass using circulating fluidised bed technology is presented in our laboratory. This improved technical concept is aiming at producing high quality gas, in terms of low tar level and particulates carried out in the fuel gas, and overall emissions’ reduction associated with fuel gas combustion, as well as stable and reliable operation with the minimum fluctuations in the producer gas volume and composition. Based on this concept, a characteristic theoretical modelling approach involving hydrodynamics, chemical reaction kinetics, and energy balance is accordingly discussed. In addition, very preliminary experimental results from a laboratory-made test rig are also given.

溶接の高速化技術の動向 ４ 自動車産業における高品質・高速ＭＡＧ溶接

溶接の高速化技術の動向 ４ 自動車産業における高品質・高速ＭＡＧ溶接

Integrated Oil Shale Processing into Energy and Chemicals Using Combined-Cycle Technology

Oil shale integrated processing and an exhaustive utilization of its energy and chemical potential are described herein. The principal features of this method are two-stage oil shale processing and power cogeneration by means of the combined-cycle turbine unit As a result of the two-stage processing, two principal products—gas and liquids—are obtained. The gas is used for power production in a combined-cycle unit The liquid products have a simpler composition, as compared to the usual shale oil, and can be an excellent source for the production of chemicals. This scheme is more effective from the technical and economical point of view and less harmful to the environment than usual retorting or direct oil shale combustion. Preservation of the environment is achieved through the use of high-quality, ashless, moistureless, and sulfurless gas fuel in place of oil shale (or sulfur-rich shale oil), and elimination of other wastes.

98/01382 Small scale gasification of short rotation coppice willow for electricity generation: Dawson, W. M. et al. Biomass Energy Environ., Proc. Eur. Bioenergy Conf., 9th, 1996, 2, 1289–1294. Edited by Chartier, P., Elsevier, Oxford, UK

Conversion technologies for wood chip produced from short rotation coppice willow have concentrated on small dispersed systems suitable for the farm structure found in Northern Ireland. The development of a 100 kW downdraft gasification, combined heat and power system identified a number of problems including fuel characteristics and gas clean up. Modifications to fuel feed systems, hearth design and particulate and tar removal methods have resulted consistent production of high quality gas for the diesel engine used for electricity generation.

Moisture Fraction Measurements for Two-Phase Mist Flow Using High-Sensitivity Capacitance Sensors

A capacitance-type sensor whose sensitivity is sufficiently high to detect liquid water droplets in a stream of gas with very low moisture content is described. Instantaneous capacitance is measured for a probe consisting of two closely spaced parallel plates through which a two-phase mixture is flowing; the presence of liquid within the sensor’s active volume generates a measurable capacitance increase due to the much higher dielectric constant of liquid water compared with gas or steam. Proof-of-concept experiments were carried out to determine the relative effects of droplet size, velocity, and position on the output of the sensor. The probe detected individual water droplets in the range of 7.5 to 20.0 μl and had a voltage output that was linear with droplet volume in this range. In addition, the signal pulse width was found to be a sensitive indicator of droplet velocity. The data indicate that the probe can be used to measure the moisture fraction of a high-quality gas flow in the range from 0 < β <0.013 (liquid volume/total volume) with a maximum standard deviation of ∼0.001.

Gases for increased productivity of laser processing

To achieve a high return on investment, laser systems must be used to their fullest capacity, avoiding power losses and downtimes. High-quality laser gases are therefore needed to run the laser. But if the quality of the gas cannot be guaranteed all the way from the cylinder to the laser cavity, the risk of impurities such as water vapour and hydrocarbons or particles being entrained into the laser system is large. Unstable laser operation and damage to the resonator optics can result, needing costly repairs.

Preparation of tin oxide ultrafine particle films

This paper presents a procedure of dc gas discharge activating reaction deposition for preparing ultrafine particle films. The dependence of the properties of the films on preparation and post-treatment conditions was studied. The result shows that the samples resemble the morphology of ultrafine particles and have a mean particle size of about 50 nm. The three beams of electron, ion and laser can greatly change the morphology and particle size of the samples. This may be a way to modify tin oxide ultrafine particle films and obtain the required properties. The ultrafine particle films prepared by this procedure may serve as high-quality gas sensors.