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 Å 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.

     

Allothermal Fluidized Bed Reactor for Steam Gasification of Biomass

This article evaluates a hybrid multi-compartment cyclic fluidized-bed reactor for the allothermal steam gasification of biomass. The concept combines space and time delocalization to approach an ideal allothermal gasifier. Thermochemical conversion of biomass in time and space sequences of steam biomass gasification and char/biomass combustion is envisioned in which the exothermic combustion compartments provide heat into an array of interspersed endothermic steam gasification compartments. This concept may enhance unit heat integration and thermal efficiency while procuring nitrogen-free synthesis gas without requiring addition of oxygen (or air) to the steam gasification compartment nor contact between the flue gas and the synthesis gas. The strengths and weaknesses of existing autothermal and allothermal gasification technologies are analyzed and a new allothermal reactor concept is introduced. Elements of gasification chemistry, fluidization hydrodynamics, and heat transfer requirements are described that are relevant for the design of the multi-compartment fluidized-bed gasifier/combustor. A preliminary design of the experimental hot mock-up is presented, including a discussion of process diagrams and mass balance.     

Effect of various gas compositions on gas interchangeability and combustion characteristics for domestic appliances

In this study, an investigation into the gas interchangeability and combustion characteristics of various gas compositions for domestic appliances was performed. In order to suggest the appropriateness of gas interchangeability using the specific gravity (SG) and the Wobbe index (WI) values, combustion characteristics included incomplete combustion and flame lifting were measured and observed for the upper and lower limits using the gas-oven as a domestic partial-premixed type appliance and the condensing boiler as a domestic premixed type appliance. The flame was stable, and the CO and NO_x concentrations increased when the WI and SG values increased. Specifically, the behavior of the flame lifting changed between WI values of 52.0 MJ/Nm³ and 53.0 MJ/Nm³. The CO and NO_x concentrations of the reference gas were approximately 173 ppm and 74 ppm for the gas-oven and 175 ppm and 35 ppm for the boiler, respectively. Consequently, a WI value of 53.0 MJ/Nm³ can be considered the flame lifting limit as the lower limit for gas interchangeability. For the upper limit of gas interchangeability, the CO and NO_x concentrations varied significantly with the type of burner.     

Biopolymer wear screening rig validated to ASTM F732-00 and against clinical data

Abstract

The ASTM standard F732-00, 'standard test method for wear testing of polymeric materials used in total joint prostheses' offers several pieces of data against which a test rig for such biopolymers can be validated. These conditions include a linear wear in the range from 0˙07 to 0˙2 mm/million cycles for ultrahigh molecular weight polyethylene (UHMWPE), and a wear rate ranking of poly tetra fluoro ethylene (PTFE)>>polyacetal≥UHMWPE. Using a modified pin on plate wear test rig, these three biopolymers were tested under a 40 N load against polished stainless steel plates while using dilute bovine serum heated to 37°C as the lubricant. When subject to multidirectional motion, mean wear factors of 37×10^–6 mm³ Nm^–1 for PTFE, 3˙8×10^–6 mm³ Nm^–1 for polyacetal and 1˙1×10^–6 mm³ Nm^–1 for UHMWPE were obtained. Therefore the wear ranking recommended by the ASTM standard was achieved. When the corrected mean weight loss of the UHMWPE test pins was converted to a linear wear rate, a value of 0˙12 mm/million cycles was obtained. Therefore the ASTM recommended target for linear wear rate was met. When the wear factors from the test materials were compared with clinical wear factors of 37×10^–6 mm³ Nm^–1 for PTFE, 3˙5×10^–6 mm³ Nm^–1 for polyacetal and 0˙95– 1˙45×10^{– 6} mm³ Nm^–1 for UHMWPE, good correspondence between in vivo and in vitro wear factors was obtained, further validating the modified pin on plate wear test rig.     

Time-Of-Flight Mass Spectrometry,Instrumentation and Applications in Biological Research

Abstract

There is no serious information in the existing literature on the levels of radioactive ⁷Be in sewage sludge. Our research took the form of a baseline study to provide suitable information in this respect. In addition, the sludge is converted to fertilizer, which can lead to radioactive contamination of streams and underground water supplies by agricultural run‐off. According to the documented literature, the acceptable level of radioactivity in domestic water supplies is <0.1 Bq/L. The levels in the sludge were up to three orders of magnitude higher. We subsequently investigated the distribution of this radioactivity over a 3‐year period. Our study involved measurement, by gamma ray spectroscopy, of ⁷Be in sludge and corresponding waste water specimens, and evaluation of its distribution over a period extending from March 2000 to March 2003. The sludge and disinfected effluent samples were collected thrice monthly, and subjected to high‐resolution gamma‐ray measurement with a 28‐cm² Ge detector. Sludge sample masses of typically 700 g (dry weight) were prepared in suitable Marinelli beakers and counted for 12 hr. The liquid specimens (1 L) were treated in the same way. It was important for the disinfected water to be free of ⁷Be, as it was used for irrigation. Variations in ⁷Be activities were observed in all the analyzed sludge samples and studied as a function of time. The presence of ⁷Be was identified by the appearance of the characteristic 478 keV gamma ray and the computed half‐life of 53 days. The documented sources of environmental ⁷Be reveal that it generally arises from cosmogenic interactions. In the present investigation, ⁷Be activities up to 40 Bq/kg above the background were recorded and no appreciable activity was monitored in the liquid disinfected specimens. A suggestion to deplete the activity levels in the sludge prior to its use as a soil conditioner is outlined. Such preventative remediation is of considerable practical importance to environmental science, and to the future well‐being of the local biosphere. The study, therefore, formed an interesting contribution to research associated with the environment.     

Effect of thermal decomposition products of coal on anodic reactions in direct carbon fuel cells

The effect of inherent volatile matter in fuels on anodic electrochemical reactions was investigated in a direct carbon fuel cell (DCFC). Through thermal decomposition, raw coals, which are used as power source in the DCFC system, release gases under an operating temperature of 700°C. These exhaust gases change the gas composition around the anode and affect the system’s electrochemical reaction. To investigate the effect of produced gases, a comparative study was conducted between Indonesian sub-bituminous coal and char obtained through thermal treatment. The open circuit voltage of raw coal increased to 0.23 V compared with that of char. The maximum power density of raw coal (52 mW/cm²) was also higher than that of char (37 mW/cm²) because of the enhanced electron transport caused by the additional reaction of hydrogen, methane, and carbon monoxide. The influence of volatile matter on the anodic electrolyte-electrode interface was analyzed with the use of the equivalent circuit induced from fitting the impedance data.     

Performance characteristics of an integrated power generation system combining gas turbine combined cycle,carbon capture and methanation

This study analyzes the performance of an integrated power generation system that combines a gas turbine combined cycle (GTCC) with a methanation process. The methanation process uses hydrogen provided by a power-to-gas (PtG) process and carbon dioxide captured from the exhaust gas of the GTCC. The research aim was to maximize the GTCC performance through an effective integration between the GTCC and methanation. Two methods were proposed to utilize the steam generated from the methanation process. One was to supply it to the steam turbine bottoming cycle of the GTCC, and the other was to inject it into the GT combustor. Also investigated was the injection of oxygen generated in the PtG process into the gas turbine combustor. The largest improvements in the power and efficiency were predicted to be 19.3 % and 4.9 % through the combination of the steam supply to the bottoming cycle and the oxygen injection to the combustor.

     

Colorimetric determination of mercury vapor using smartphone camera-based imaging

The smartphone camera presents a convenient, portable, and low-cost innovation in colorimetric measurements. In this paper, a smartphone camera was applied for the colorimetric detection of gaseous elemental mercury, an atmospheric pollutant of concern in environment, and workplace monitoring. A cuprous iodide (CuI)/polystyrene composite was used as the recognition element, which exhibited a reddish color in the presence of Hg⁰. Digital images of the sensing reagent phase were captured by a smartphone camera and were analyzed in red–green–blue color space using ImageJ, an open source image processing program. Parameters for the digital colorimetric sensing including the color values, polymer reagent binder, amount of CuI, exposure time, and Hg⁰ concentration were investigated and optimized. The linear working range of the sensor was from 61 to 270?μg/m³ Hg⁰ with a correlation coefficient of 0.978. The limit of detection is 16?μg/m³ Hg⁰. This method shows the feasibility of applying a smartphone camera for a simple, reliable, and inexpensive colorimetric measurement of Hg⁰ vapor in a gas mixture such as air.     

富氧煤气生产新工艺的实际应用及效益

通过向混合发生炉煤气气化剂—空气中充入一定比例的O2,以提高气化剂中O2含量,降低N2含量,使原料煤在富氧的气化条件下,更加完全的进行煤炭气化反应,从而提高煤气发热值,降低灰渣含C量,提高煤炭利用率,以达到节能减排、降本增效的作用。     

裂解氢化技术在鉴别聚烯烃类塑料中加氢催化剂用量的最佳化研究

在裂解氢化气相色谱法对聚烯烃类塑料鉴别中 ,以高密度聚乙烯为实验样本 ,选用铂 10 %wt担体 (80～ 10 0目DiasolidH)加氢催化剂进行氢化反应。考察加氢催化剂用量从 0 0 0～ 94 0 0mg之间裂解产物的最佳氢化程度。实验结果表明 :当样品量控制在≤ 80 μg时 ,加氢催化剂≥ 5 4mg时 ,可满足裂解氢化技术分析的需要     

A TGA study of CO2 gasification reaction of various types of coal and biomass

The CO₂ gasification kinetics of various carbonaceous samples of high-and low-rank coal and a biomass were determined under CO₂ flow with increasing temperature in a Thermogravimetric analysis (TGA) coupled with Fourier transform infrared spectroscopy (FTIR). We utilized four different types of fuels and their chars with significant differences in their physico-chemical properties that are being most widely used in Korea. As a result, fuels with larger surface area and more catalytic components in ash were preferred for increasing the intrinsic reactivity of CO₂ gasification particularly for low-rank coals and biomass, respectively. It was postulated that the catalytic effect of ash components could compensate for the lack of active sites in the biomass samples. From the practical point of view, the utilization of the low-rank coal with the porous char structure with blending the biomass is recommended for a remarkable increase of the gasification rate.

     

Friction and wear behaviour of aluminium alloy coconut shell char particulate composites

The friction and wear characteristics of Al-11.8%Si alloys containing 10–25 vol.% (3–8 wt.%) dispersions of coconut shell char particles (average size, 125 μm) were evaluated under dry conditions with a pin-on-disc machine. At the lower sliding speed of 0.56 m s^?1, the wear rates and friction coefficients of the composites decreased with increasing volume per cent of dispersed char particles in the aluminium alloy matrix. Scanning electron microscopy observations have revealed the presence of adhering shell char fragments on the worn-out surface of the composites and the average roughness R_a for the worn-out surface of the composite (Al-11.8%Si-8%char) was much less (1.9 μm) than for the worn-out surface of the matrix (3.2 μm). At the higher sliding speed of 5.38 m s^?1, the wear rates increased with increasing volume per cent of dispersed char particles in the matrix and the R_a value for the composite (Al-11.8%Si-8%char) was higher (5.2 μm) than for the matrix (4.6 μm). The worn-out surface of the composites did not show the presence of adhering shell char fragments. The reduction in wear rates and friction coefficients of composites at the lower sliding speed of 0.56 m s^?1 with respect to the matrix alloy wear was attributed to the presence of adhered fragmented bits of shell char on the wearing composite surface.     

Tribochemical machining of polycrystalline diamond using ferrous tool materials

Abstract

This article studies the tribochemical machining of polycrystalline diamond (PCD) by utilizing ferrous tool material as the cutter. The influence of cutting parameters and different ferrous materials on the material removal rate of the PCD workpiece has been investigated. The material removal rate increases with the increase of the rpm of ferrous “cutter”, AISI 1020 steel is unable realize the tribochemical machining, and the material removal rate of using AISI 1045 steel was higher than that of using W2-21/2 steel, e.g. when rpm was 3000, the material removal rate of using AISI 1045 was 0.059?mm/min, and using W2-21/2 it was 0.020?mm/min. The surface roughness of the machined PCD workpiece using W2-21/2 (0.40?μm) was slightly improved in comparison to that produced using AISI 1045 (0.47?μm). The influence of hydrogen catalysis on tribochemical machining of PCD has been investigated. Compared with no use of steam, if a large amount of steam is continuously injected the material removal rate will significantly increase, e.g. when the rpm was 3000 (using AISI 1045) the material removal rate of no steam was 0.059?mm/min, while with steam it was 0.082?mm/min.     

Hyperthermal Atomic Oxygen Interaction with MoS<Subscript>2</Subscript> Lubricants Relevance to Space Environmental Effects in Low Earth Orbit—Atomic Oxygen-Induced Oxidation

Effect of 5 eV atomic oxygen beam exposure on the surface properties of sputter-deposited and single-crystal molybdenum disulfide (MoS₂) were evaluated in the light of space environmental effects in low earth orbit. X-ray photoelectron spectra indicated that the loss of sulfur from the atomic oxygen exposed MoS₂ surface was significant, especially for the sputter-deposited samples. This is due to the formation and gasification of the volatile product, SO. It was also identified that Mo atoms at the surface were oxidized to form MoO₃. The amount of oxygen increased within a depth of 22nm from the surface, whereas loss of sulfur was only observed within 3nm. It was thus concluded that the chemical change of MoS₂ due to atomic oxygen attack is limited to the surface layer of the MoS₂-sputtered lubricant.     

Forced convection heat transfer of steam in a square ribbed channel

An experimental study of heat transfer characteristics of steam in a square channel (simulating a gas turbine blade cooling passage) with two opposite surfaces roughened by 60 deg parallel ribs was performed. The ranges of key governing parameters were: Reynolds numbers (Re) based on the channel hydraulic diameter (30000–140000), entry gauge pressure (0.2Mpa–0.5Mpa), heat flux of heat transfer surface area (5kWm⁻²–20kWm⁻²), and steam superheat (13°C–51°C). The test channel length was 1000mm, while the rib spacing (p/e) was 10, and the ratio of rib height (e) to hydraulic diameter (D) was 0.048. The test channel was heated by passing current through stainless steel walls instrumented with thermocouples. The local heat transfer coefficients on the ribbed wall from the channel entrance to the fully developed regions were measured. The semi-empirical correlation was fitted out by using the average Nusselt numbers in the fully developed region to cover the range of Reynolds number. The correlation can be used in the design of new generation of gas turbine blade cooled by steam.     

GC-MS在内蒙褐煤型煤块低温煤焦油成分分析中的应用

采用蒸馏技术和GC-MS技术,对内蒙褐煤型煤块低温炭化产品低温煤焦油馏分进行了定性定量分析,分析结果表明:内蒙褐煤型煤块的低温煤焦油中≤340℃的馏分占焦油重量的82.88%;>340℃的为沥青,占焦油重量的17.02%。从≤340℃的馏分中定性定量出139种化合物,其中,烃类占焦油的34.38%,以脂肪族烷烃为主,烯烃、环烷烃占少量;酚类占焦油的12.01%,集中在210℃前的馏分;芳烃类占焦油的16.73%,以甲基、乙基、丙基丁基等多烷基苯的取代衍生物为主,分布在各个馏分中,萘和甲基萘的衍生物以及蒽、菲芳烃主要集中在300℃前得馏分;含氧和含氮及杂环化合物分别占焦油的4.61%,0.52%,2.23%。通过研究为褐煤低温焦油的深加工利用提供了基础数据,同时提供了分析褐煤型煤块干馏产生的低温焦油的方法。     

Traction and wear of an elastomer in combined rolling and sliding

Under combined rolling and sliding materials can experience millions of cycles as well as complex loading and slip conditions, which can dramatically affect their friction and wear behaviour. It was shown that for a carbon black‐filled natural rubber compound in combined rolling and sliding contact with a smooth alumina coated disk, the traction coefficient, as a function of slip percent, was dependent upon the normal load and independent of rolling velocity. The wear rate of this material pair was found to be independent of slip percentage as well as rolling velocity but dependent upon sliding distance. The wear rate was found to be approximately the same for all tested cases (K ~ 1 × 10⁻⁴ mm³·Nm⁻¹). The worn profiles of the ball specimens showed that this wear occurred preferentially on the left side (inner radius) of the contacting area. Copyright © 2015 John Wiley & Sons, Ltd.     

离子色谱法测定煤氮转化为NH3和HCN的行为

NH3和HCN是煤热解过程中释放的主要含氮物，其生成特性与氮氧化物的释放关系密切，因此NH3和HCN的准确测定是该研充方向的关键因素。实验用反应气氛分别为氩、甲烷、15％水蒸气／氩和15％水蒸气／甲烷，经溶液吸收的气相产物用Dionex公司DX-500型离子色谱仪分析测定，考察了热解过程中产生的NOx主要前驱物NH3和HCN的释放规律及其影响因素。在设定的实验条件和测试条件下，得到了较好的实验结果，并推断出一些有意义的结论。     

采用裂解气相色谱/质谱法剖析船用沥青

采用裂解气相色谱/质谱联用方法对三种不同类型的沥青进行分析研究,选择在550℃裂解,其裂解产物通过SE-54高效毛细管柱分离和质谱鉴定,提供了有关这三种沥青各自结构的特征信息。通过碎片峰相对峰面积的比较,可区分不同产地的石油沥青样品。具有样品无需前处理,用量少,谱图直观,对应性强,灵敏度高等特点。     

Tribological characterisation of epoxy–graphene–liquid filler composite coatings on steel under base oil external lubrication

In our earlier study, epoxy-based composites with graphene (10?wt-%) and in situ liquid fillers (base oil SN150 or perfluoropolyether at 10?wt-%) were found to provide low friction and highly wear durable as thin coatings on the steel substrate in dry interfacial state. In this present work, we have tested this composite in the presence of an external lubricant (base oil SN150). The lowest coefficient of friction was recorded as 0.04 and the lowest specific wear rate was measured as 9.8?×?10^?7?mm^3?Nm^?1 for the composites without any failure of the coating up to 200,000 sliding cycles. It is shown that such polymeric coatings can be an excellent boundary film in both dry and lubricated conditions for various bearings.