热解样品分析中重量的变化及其影响

热解除油是目前室内岩心分析中样品除油的主要方法之一，但由于热解温度较高，会对样品中粘土矿物的结构水和层间水产生较大的影响。本文结合粘土矿物的吸水特性，通过对大量的实验测定结果分析后认为：经过热解处理后的样品，在测定过程中受粘土矿物（主要是伊利石和蒙脱石）层间水变化的影响，会引起样品重量及样品孔隙空间体积的变化，从而对物性分析中孔隙度测定结果产生较大的影响。     

Autothermal two-stage gasification of low-density waste-derived fuels

In order to increase the efficiency of waste utilization in thermal conversion processes, pre-treatment is advantageous. With the Herhof Stabilat^® process, residual domestic waste is upgraded to waste-derived fuel by means of biological drying and mechanical separation of inerts and metals. The dried and homogenized waste-derived Stabilat^® fuel has a relatively high calorific value and contains high volatile matter which makes it suitable for gasification. As a result of extensive mechanical treatment, the Stabilat^® produced is of a fluffy appearance with a low density. A two-stage gasifier, based on a parallel-arranged bubbling fluidized bed and a fixed bed reactor, has been developed to convert Stabilat^® into hydrogen-rich product gas. This paper focuses on the design and construction of the configured laboratory-scale gasifier and experience with its operation. The processing of low-density fluffy waste-derived fuel using small-scale equipment demands special technical solutions for the core components as well as for the peripheral equipment. These are discussed here. The operating results of Stabilat^® gasification are also presented.     

Depollution of atmospheric emissions of wood pyrolysis furnaces

The wood carbonization in Tunisia consists essentially of traditional activity using charcoaling stacks and pits characterized by high atmospheric pollution and poor energy conversion. Indeed, 70% of the initial mass of anhydrous wood are found in the vapor as aerosols, polluting and toxic gases and complex condensable organic compounds that can cause a substantial pollution of air, ground and water. Several processes of treatment and energy valorization of such effluents were proposed, but the incineration remains at present the most promising technique of depollution. The results show that the incineration, at about 1000°C, of wood carbonization smokes allows the destruction of 99% of the mass of pollutants except CO₂ and the reduction of polluting gas emission. The possible valorization of the smoke’s energy in the exit of the incinerator enhances the thermal efficiency of the process.     

Characterization of CuInS2 thin films for solar cells prepared by spray pyrolysis

We have made a study of the chemical composition, the electrical, the optical and the structural properties of polycrystalline CuInS₂ thin films prepared by spray pyrolysis to be used for thin film solar cells. These films were deposited starting from aqueous solutions with different chemical compositions ([Cu]/[In] and [S]/[Cu] ratios) and at different substrate temperatures. In all cases, the material is p-type with grains preferentially oriented in the (112) direction of the sphalerite structure. The electro-optical properties show a very strong dependence on the [Cu]/[In] ratio in the solution. Films with copper excess have smaller resistivity and better crystallinity than those which are stoichiometric or have indium excess. The results obtained in this work show the possibility of having CuInS₂ thin films with a wide range of resistivity, a fact that could be important for making solar cells based on this material.     

Improved sooting tendency measurements for aromatic hydrocarbons and their implications for naphthalene formation pathways

Sooting tendencies have been determined for aromatic hydrocarbons using a new definition: the maximum soot volume fraction fv,max measured in a coflow methane/air nonpremixed flame whose fuel is doped with 400 ppm of the test hydrocarbon. These fv,max were converted into apparatus-independent yield sooting indices (YSIs) by the equation YSI=C×fv,max+D, where C and D are apparatus-specific parameters chosen so that YSI-benzene = 30 and YSI-1,2-dihydronaphthalene = 100. The dopants were added to the fuel mixture with a syringe pump and fv,max was measured with laser-induced incandescence. YSI was determined for 6 cycloaliphatics and for 62 aromatics, which included 28 alkylbenzenes, 10 alkenylbenzenes, 10 alkynylbenzenes, 25 multiply substituted benzenes, 6 two-ring aromatics, and 6 substituted benzenes with heteroatoms in the side chains. The YSIs correlate well with literature values of threshold sooting index (TSI), which is a more traditional sooting tendency based on the height of pure-fuelled flames at the smoke point. This agreement indicates that fv,max and smoke height are equivalent measures of sooting tendency and that YSI is largely apparatus-independent. However, the YSIs have a total uncertainty of ±3%, which is substantially better than the TSIs, and the number of aromatic YSIs reported here is more than double the number of aromatic TSIs in the literature. The YSIs depend strongly on molecular structure; thus they provide information about the chemical kinetic reaction mechanisms responsible for fuel decomposition and hydrocarbon growth from a broad cross section of one-ring aromatics. Important naphthalene formation pathways appear to include acetylene addition to ethynylphenyl, propargyl addition to benzyl, and methyl addition to indenyl. This last pathway is particularly significant because it converts indene quantitatively to naphthalene and because the side chains in many alkenylbenzenes and alkynylbenzenes cyclize to form five-membered rings.     

A MODEL OF A PYROLYSIS GASIFIER FOR PREDICTION COMPOSITIONS AND FLOU RATE OF PRODUCED GAS

A model of pyrolysis gasifier, which is mainly composed of a pyrolysis, a cracking and a combustion chamber, it developed to predict its performance parameters and to simulate its operation. Toe model consists of a pyrolysis-cracking sub-model, a secondary gasification sub-model and a combustion sub- model, of which the pyrolysis-cracking sub-model is modified to predict components of tbe pyrolysis gas. Then, It with the other two sub-models can predict components, heating value and flow rate of the produced gas, thermal efficiency and total energy efficiency of the gasifier as ell. Crank-Nicolson Scheme (half implicit difference formulation) in which the time step is not confined by stability and the cutting error is small, is applied to solving the model whose differential equations are nonlinear and have no analytic solution. Theo, the nonlinear difference algebraic equations are solved by interalions, which requires less storage of computer. Underrelaxation is applied to avoiding divergence of Causs-Seidel interations. Finally, the simulated results are input to Software Lotus 1-2-3, by which the results are printed and graphed so as to compare with the experimental ooes, and it shots acceptable agreement, thus validate the model.     

Synthesis of nano Sb-encapsulated pyrolytic polyacrylonitrile composite for anode material in lithium secondary batteries

A novel process was proposed to synthesize nano Sb-encapsulated pyrolytic polyacrylonitrile composite for anode material in lithium secondary batteries. The preparation started with the dissolution of SbCl₃ and polyacrylonitrile (PAN) in dimethylformamide (DMF) solution, followed by the addition of KBH₄ to reduce Sb³⁺ in the solution. The Sb composite was obtained by pyrolysis of the Sb/PAN mixture that precipitated out when the DMF solution was added by plentiful water. The TEM analysis showed that about 100-200 nm Sb particles were embedded by the pyrolyzed PAN, which provided a conductive matrix to relieve the morphological change of Sb during electrochemical cycling. As-prepared composite presented good cycleability for lithium storage. The proposed process paves an effective way to prepare high performance alloy based composite anode materials for high performance lithium-ion batteries.     

Carbonaceous adsorbents from sewage sludge and their application in a combined activated sludge-powdered activated carbon (AS-PAC) treatment

In this study, waste biological sludge is converted to an adsorbent by chemical activation with sulphuric acid. The adsorbent obtained is then applied to the aerated vessel of an activated sludge process treating glucose and phenol to improve the quality of the treated effluent. The sludge-based carbonaceous adsorbent was found to be mesoporous in nature, with a good adsorption capacity for large molecular weight compounds and limited removal efficiency for smaller molecules such as phenol. The addition of carbon, either sludge-based or commercial, enhanced phenol removal from 58% to 98.7% and from 87% to 93% the organic matter removal as measured by the chemical oxygen demand (COD) when operated with feed concentrations of 100 mg phenol/l and 2500 mg COD/l. No differences were found between the activated sludge-activated carbon bench scale continuous reactors operating with either commercial or sludge-based adsorbents in spite of the higher adsorption capacity of the former. It is suggested that powdered adsorbent bioregeneration in the combined AS-PAC system may be impaired by the obstruction of pores due to bacterial growth, the effect being more important for the commercial activated carbon with a narrower pore size distribution.     

影响裂解汽油二段加氢催化剂长周期运转因素及解决措施

从裂解汽油二段加氢催化剂性能、裂解汽油和操作条件等方面论述了影响该催化剂长周期运转的因素,并针对这些因素提出相应的措施,以达到延长催化剂运转周期的目的。