Abstract Booklet 2006 - Swanson School of Engineering - University ...

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Coal gasification is becoming commercially even more important due to its potential application in hydrogen, ammonia, methanol and other chemicals and clean fuels production, other than power generation, together with carbon dioxide capture and sequestration. In this framework the technological development is also addressed, with a renewed interest, to simplified processes and plant solutions based, for example, on gasification with air (or air enriched with oxygen) and on moving or fluidised bed gasifiers, of interest for small and medium scale plants. The design, analysis and performance evaluation of the overall system (gasification, gas clean-up, desulphurisation, CO-shift conversion, CO 2 and hydrogen separation, etc.) require a preliminary estimation of gasifier mass and energy balances and raw gas composition, which influence the whole downstream gas clean-up and treatment systems. The present study reports a process analysis and performance evaluation of updraft moving bed gasifiers, which have been carried out by a computer simulation model developed using the Aspen Plus 12.1 software, The model schematises the gasifier in several different zones: coal preheating and drying, devolatilization, gasification, combustion and oxidant preheating, under the hypothesis of char gasification at thermodynamic equilibrium. The model allows to appraise the mass and energy balance of the gasifier and the main characteristics of the syngas produced by the gasification process (composition, mass flow, temperature, lower heat value, etc.), being assigned coal composition and coal, steam and oxidant (air eventually enriched with oxygen) mass flows. In this paper the model is applied to predict the performance of two updraft moving bed gasifiers (sized respectively for 35 kg/h and 700 kg/h of low sulphur coal and high sulphur coal (Sulcis). The gasifiers are part of a small pilot gasification and gas treatment plant for hydrogen production under construction at the Sotacarbo Research Centre in Sardinia. SESSION 50 COAL CHEMISTRY, GEOSCIENCES, AND RESOURCES: COAL CHEMISTRY 50-1 The Pore Structure of Coals Dewatered by Mechanical Thermal Expression (MTE) Alan L. Chaffee, Janine Hulston, Yuli Artano, Monash University, AUSTRALIA Christian Bergins, Christian Vogt, Karl Strauss, University of Dortmund, GERMANY The mechanical thermal dewatering (MTE) process has been shown to effectively dewater high moisture low rank coals via the application of mechanical force at elevated temperatures. The MTE process produces a low porosity product coal, which undergoes further shrinkage upon drying. In this study, the porosity and its development within MTE products has been probed through a combination of geometric measurements, helium pycnometry and mercury intrusion porosimetry (MIP). An advantage of MIP is that it allows pore size distributions to be determined over a broad pore size range, spanning several orders of magnitude. The technique however has its limitations, in that samples need to be completely dry. Thus porosity and pore size distribution data can only be obtained for dried MTE products, which have undergone shrinkage. Moreover, care must be taken when interpreting the mesopore diameter range (2-50 nm), as the high intrusion pressures required to measure pore sizes in this region may also lead to sample compression. This can be compensated if the inherent compressibility, κ, of the sample is known and the raw data is adjusted accordingly. Most prior work in the literature has taken no account of the coal’s compressibility, κ; or, if κ has been considered, it has been determined by extrapolation of the intrusion portion of the MIP curve in the high pressure region (>100MPa, at least) where there (sometimes) appears to be a linear relationship between the cumulative intrusion volume and pressure. However, if mesopore filling is still occurring in this region the compressibility, κi, determined by this method will clearly be compromised. Consistent with this understanding, the values of κ determined in this study from the intrusion portion of the curve varied from sample to sample and were observed to increase as the proportion of pores in the mesopore size domain increased. In contrast, the compressibilities determined from the extrusion portion of the curve, κe, were relatively constant for all MTE products prepared from the same coal. Thus, it is inferred that the extrusion data provide a better measure of the true compressibility of a coal and more correctly account for elastic deformations in the coal’s macromolecular network (consisting of not only coal, but also closed or inaccessible pores and unfilled micropores) that occur under the influence of high fluid pressures. Moreover, the skeletal densities determined from MIP, after correcting for the compressibility (using κe), are lower than the He densities determined by pycnometry, in accord with physical reality (and unlike the skeletal densities determined using κi). Elimination of the compressibility effects then facilitates the calculation of micropore (pores < 2nm diameter) volumes which are physically sensible and appear consistent with values determined by other approaches. 50-2 Direct Sourcing of Coal: Part-I -Solubilization of Coal from North Eastern Region of India Debapriya Choudhury, Raja Sen, Gora Shosh, Sunil K. Srivastava, Central Fuel Research, INDIA 44 High Performance Engineering plastics are being touted as materials of the future. Already quite a few such polymers are already in the market e.g. Kevlar from Dupont, Xydar from Amoco, Vectra from Hoechst Celanese. Polyethylene Napthalate (PEN) from Teijen and Amoco. Most of the high performance polymers are aromatic polymers or liquid crystal polymers, both of which are derived from aromatic monomers. However mass use of such polymers are inhibited by their much higher cost. However with rapidly growing market demand of such polymers the demand of aromatic monomers are also increasing rapidly and will continue to so in the near future. However contrary to this increasing demand this availability of aromatics particulars, 2-4 ring compounds has declined significantly due to world wide decline in production of coal tar which continues to be major source of 2-4 aromatic ring compounds. The main reason for the decline in coal tar production is linked with the worldwide decline in steel production, which concomitantly reduces coke production, and this in effect reduces coal tar production. Furthermore development of newer steel technologies like direct coal injection etc. have decreased this demand of coke and with adoption of these technologies coke product and as a result tar product is likely to fall rapidly in the coming decades. Moreover by product coke oven opera is now sensed to be an extremely environment unfriendly operations and with enforcement of more stringent environmental standards blast furnace steel technologies which is directly related with coke making is expected to be replaced by these newer technologies. Although coal tar still continues to be the major source (about 95% of the world production) for 2-4 ring aromatics, the total process is not very efficient vis a vis production of chemicals considering that good quality bituminous coal produces only around 30 liters of tar which then consists only of about around 25% of two to four ring aromatics of which are present in very small quantities. Furthermore coal tar is an extremely complex mixture and separation of various components particularly those present in lower concentration make it a rather costly operation However as such technological trends which is leading to reduction in tar production are an anti thesis of the trend of increasing demand of 2-4 aromatics and therefore there is urgent need for development of newer technologies for their production in on sustainable if not on mass scale. Two broad strategies have been proposed in this regard, one being the indirect route and the other direct. The indirect route consists of coal conversion route and coal liquefaction, which involves basically separation of the coal liquids obtained, followed by further conversion if necessary to produce the chemicals of interest. Short contact time coal liquefaction followed by catalytic de-alkylation to obtain aromatic monomers as suggested by some authors (1,2) is a good example of such a concept. However coal liquefaction products are again complicated mixtures which will require complicated and time consuming separation techniques which will add to the cost of the chemicals produced, an inhibiting factor in mass production as discussed before. However direct sourcing of coal for production of value added products particularly for production of monomers for high performance engineering plastics is a much bolder and challenging strategy, although definite technologies have yet to be fully developed. Coal is predominantly an aromatic material, the structure of which contains crosslinked polyaromatic units of three or more rings having hydroaromatic and aliphatic structures as peripheral groups. Unfortunately for the chemical industry the aromatic part contributes solely to coke formation and is not therefore available for preparation of aromatics. The direct sourcing route proposes to use these aromatic units in coal macromolecule available as aromatic monomers (of three or more rings) or precursor of such monomers. The methods proposed envisage processes for scission of certain target bonds (mainly bridging bonds) between the polyaromatic units. A similar method suggested by Song and Schobert (3) for generating high yields of benzene carboxylic acids from selective oxidation of low rank coals is a good example. In NorthEastern region of India about 900 million tones of high sulfur coal is available but that has to be judiciously utilized. About 75-90% of the total sulfur is in the organic form that also mostly in thiophenic & thio-ketonic form, which is very difficult to remove. The pyretic sulfur is highly disseminated in the organic matrix of coal hence can not be separated by physical processes. Therefore use of high sulfur NE region coal in any industry possess a limitation. Hence its gainful utilization in an environment friendly way is the need of the day. This paper explores the method of coal oxidation with dilute nitric acid as a possible method for oxidative degradation of coal to produce benzene carboxylic acids as precursors for such monomers. The coals used for these studies are coals from NE region of India which have limited application in conventional coal based industries, in spite of substantial reserves (about 900 MT), considering it high organic sulfur content combined with highly disseminated pyrite which is difficult to remove physically. 50-3 Transformation of the Fe-Mineral Associations in Coal during Gasification Frans Waanders, North-West University, SOUTH AFRICA John Bunt, Sasol Technology, SOUTH AFRICA The mineral matter associated with coal undergoes various transformations during the coal gasification process. Optimisation of the gasification process is necessary in the coal to liquids technology. The principle aim of this investigation was to determine the changes that the Fe-containing minerals and mineral associations undergo during gasification of coal. Due to the complexity of the counter-current coal-gas process used, a gasifier dissection was undertaken on one of the Sasol gasifiers. Detailed characterisation profiles of various properties of the coal were undertaken after a
commercial-scale gasifier was shutdown for routine maintenance of which the Mössbauer spectroscopy technique will be described here. Representative samples from the gasifier were extracted after sufficient cooling was done to allow the safe turn-out of the gasifier. In the coal samples that entered the gasifier, pyrite was the abundant Fe-containing mineral, whilst the pyrite changed gradually to form, in conjunction with the SiO 2 and Al 2 O 3 present in the coal, a Fe-containing glass and hematite at the bottom, or ash grate of the gasifier. 50-4 Uneven Distribution of Sulfurs and Their Transformation during Coal Pyrolysis Baoqing Li, Fenrong Liu, Wen Li, Haokan Chen, Chinese Academy of Sciences, P.R. CHINA Two Chinese coals, Liuzhi high pyrite coal with high ash content (LZ) and Zunyi high organic sulfur coal (ZY), were pyrolyzed in a fixed-bed reactor under nitrogen and hydrogen at temperature ranging from 400 to 700ºC. The effects of heat rate, temperature and gas atmosphere on sulfur transformation and sulfur uneven distribution were examined by XPS combined with traditional sulfur analysis method. The ratio of surface S to bulk S is used to describe the uneven distribution of sulfurs. It is found that oxygen is rich on the surface, while S in the bulk. The increasing ratio of surface S to bulk S with increasing temperature clearly indicates the sulfur transfer from the bulk to the char surface during pyrolysis. The ratios are higher at all temperatures studied for ZY coal than for LZ coal, which may be related to the higher ash content in LZ coal. The ratio of surface S to bulk S increases with increasing heating rate for LZ coal, while it decreases for ZY coal. In the presence of H 2 , the S on the surface is much lower than that under N 2 and surface S in sulphidic, thiophenic and sulfoxide forms is totally disappeared for LZ coal at various temperatures and heating rates, while the surface S in thiophenic and sulfoxide forms is not totally disappeared for ZY coal, which may be related to the high rank of ZY coal. The ratio of surface S to bulk S decreases before 600ºC with increasing temperature for both coals in the presence of H 2 , showing that gaseous H 2 can easily react with the surface S to form H 2 S, while above 600ºC it increases because the supply of H 2 cannot match the rate of formation of HS· free radicals at high temperature. 50-5 Advanced Carbon Foams from Coal Drew Spradling, Touchstone Research Laboratory, USA Carbon foams manufactured from bituminous coal feedstocks have seen increasing application in composites manufacturing and in naval shipbuilding, due to the unique properties of these lightweight materials. In the unique manufacturing process, pulverized coal is converted into a lightweight, high strength, open cell carbon foam with highly uniform pore size distribution, and tailorable electrical and mechanical properties. A state-of-the-art manufacturing facility is being commissioned and large cross-sections of carbon foam are being consistently produced on a limited commercial volume scale. Many advanced applications ranging from aerospace composites to naval shipbuilding have been demonstrated through subscale component qualification testing. As an example, carbon foam is being tested as a potential material for the new Navy DDX class warship. Prototype testing in the deckhouse composite structure is underway, with the carbon foam providing low radar cross-section, corrosionresistance, excellent electromagnetic shielding effectiveness, and the ability to meet fire, toxicity, and smoke requirements. The material has been demonstrated that it can be integrated into the ship s planned composite and steel structures. In the development of the carbon foam materials, extensive coal chemistry studies were performed, leading to a comprehensive understanding of the controlled coking nature of the manufacturing process. During manufacturing, the fluid and devolatilization properties of the coals are manipulated with precise control of the heating, pressure, and atmosphere variables necessary to produce large quantities of highly uniform foam. High pressure autoclaves and atmosphere furnaces have been custom designed for this unique manufacturing process. Extensive characterization of the different carbon foam grades produced, allows for advanced material application such as those found in the aerospace and defense industries. Mechanical, electrical, and acoustical properties of the foam were extensively characterized, leading to the selection of appropriate application in areas where conventional materials are inferior. A brief overview of the carbon foam production process, as well as some of the unique applications of this advanced carbon material will be presented. SESSION 51 MATERIALS, INSTRUMENTATION, AND CONTROLS – 3 51-1 Studies on the Preparation of Mesophase Pitchs by Thermal Conversion of a FCC Slurry Xiaolong Zhou, Jing Chen, Guoxian Yu, Cheng-lie Li, East China University of Science and Technology, P.R. CHINA Minglin Jing, Zuo Zhang, Shanghai Institute of Technology, P.R. CHINA Ordered mesophase pitch was prepared by thermal polymerization of a fluid catalytic cracking (FCC) slurry stock. Thermal conversion experiments were performed on a multi-tube well-shape crucible programmed heated furnace. Optical microscope observation and solvent extraction separation were used to elucidate formation behaviors of ordered mesophase. It has been indicated from our work that there are three steps, i.e., containing the formation of the mesophase micro-crystal, the growth of mesophase micro-crystals and the coalescence of mesophase spherules. The former two steps are slow, whilst the last is a fast one. In addition, a novel tubular reactor reducing in the central section was designed to guide the ordered growth of mesophase spherules under the oriented flowing gas stream by thermal cracking. The optical structure observation showed that anisotropic mesophase fibrous structures were first formed radial-in-ward around the reaction tube wall. At prolonged time on stream (TOS), such structures further developed from the wall toward the centre of the tube and thus form a ring-shape structure. 51-2 Effect of KOH in Preparation of Activated Carbon with Low Ash Content and High Specific Surface Area from Law Rank Bituminous Coal Jin Lei, Qiang Xie, China University of Mining and Technology, P.R. CHINA An experimental study on the effect of K-containing compounds in preparation of coalbased activated carbon was conducted in this paper. KOH was used in the cocarbonization with coal, changes in graphitic crystallites in chars derived from carbonization of coal with and without KOH were analyzed by X-ray diffraction (XRD) technique, activation rates of chars with different contents of K-containing compounds were deduced, and resulting activated carbons were characterized by nitrogen adsorption isotherms at 77 K and iodine numbers. The results showed that the introduction of KOH into the coal feedstock before carbonization can realize the intensive removal of inorganic matters from chars under mild conditions, especially for the efficient removal of dispersive quartz, an extremely difficult separated mineral component in other processes else. Apart from this, KOH demonstrates a favorable effect in control over coal carbonization with the goal to form nongraphitizable isotropic carbon precursor, which is a necessary prerequisite for the formation and development of micro pores. However, the K-containing compounds such as K 2 CO 3 and K 2 O remaining in chars after carbonization catalyze the reaction between carbon and steam, which leads to the formation of macro pores. In the end an innovative method, in the light of which KOH is added in coal feedstock before carbonization and K-containing compounds are removed by acid washing after carbonization, was proposed for the synthesis of coal-based activated carbon with ash content less than 10% and specific surface area more than 1600 m 2 /g. 51-3 Effect of the Coking-Coal Property Change on Blend Quality and Coke Microstructure Gaifeng Xue, Peng Chen, Shangchao Liu, Wuhan Iron and Steel Corporation, P.R. CHINA By studying the vitrinite reflectance and its distribution, technical indexes of the single coal and blended coal for coking in WISCO in recent years, it was discovered that the single coal quality changed obviously, especially the metamorphism, its changes obviously affected blended-coal qualities and coke microstructure. 51-4 Experimental Research on Coke Braise as a Cokemaking Additive Shizhuang Shi, Wuhan University of Science and Technology, CHINA Xueying Zhou, Wuhan Iron and Steel Corporation, P.R. CHINA The experiment of suitability of coke braise with coking coal was carried out firstly and then cokemaking experiment, coke braise as an additives and petroleum coke for a comparison, was carried out in a semi-commercial scale. The influence of particle size and its distribution, proportion of coke braise and property of coke-oven charge on coke quality was researched. The experimental results show that there is a good suitability between coking coal and coke braise; For high quality of coke, the particle size of coke braise should be less than 0.45mm. The addition of 3% coke braise is feasible under the condition of routine production in Coking plant of WISCO. The effect of addition of 3% coke braise is superior to the effect of addition of 3% petroleum coke. 51-5 Study of CH 4 -H 2 O In Coke-Oven Reforming to Produce Syngas Catalyzed by Carbon Catalyst Yongfa Zhang, Wei Zhao, Huawei Zhang, Xiling Miao, Yan Liang, Guojie Zhang, Yaling Sun, Kechang Xie, Taiyan University of Technology, P.R. CHINA Coke-oven gas that contains mainly 57~62% H 2 , 25~28% CH 4 , and ~6% CO is a high quality hydrogen resource. However, coke-oven gas that contains more organic sulfur such as COS, thiophene S, and more tar can not be converted into syngas easily by Nicatalyst process. Based on this limitation a new kind of catalyst, carbon catalyst for reforming CH 4 .in coke-oven gas to syngas was studied. The research of CH 4 -H 2 O (in 45
Page 1 and 2: TABLE OF CONTENTS Oral Sessions Pag
Page 3 and 4: 1-1 SESSION 1 GASIFICATION TECHNOLO
Page 5 and 6: The U.S. pioneered development of s
Page 7 and 8: 5-5 Enhanced Hydrogen Production wi
Page 9 and 10: derived synthesis gases employing i
Page 11 and 12: Several physical adsorbents, partic
Page 13 and 14: 13-1 SESSION 13 GASIFICATION TECHNO
Page 15 and 16: promising Clean Coal technologies u
Page 17 and 18: high selectivity (theoretically pro
Page 19 and 20: 19-3 Development of Highly Efficien
Page 21 and 22: The Aim of the project is the impro
Page 23 and 24: 24-3 Development of Fluidizable Lit
Page 25 and 26: the classical Lurgi-gasifcation pro
Page 27 and 28: 28-5 A Kinetic Approach to Catalyti
Page 29 and 30: turbine cycles. The models provide
Page 31 and 32: up to 290 psia and temperatures up
Page 33 and 34: 35-2 Development of Iron-Based Pero
Page 35 and 36: features of the BGL 1000 technology
Page 37 and 38: Heat-exchangers, particle filters,
Page 39 and 40: 41-4 Using Fly Ash-Based Foundry Co
Page 41 and 42: ocks using elemental ratios. Data f
Page 43 and 44: 600-900°C. Changes in the amount o
Page 45: ATL process has three stages, namel
Page 49 and 50: 52-5 Pilot-Scale Demonstration of U
Page 51 and 52: POSTER SESSION 1 COMBUSTION TECHNOL
Page 53 and 54: experimental data available in lite
Page 55 and 56: activation. It was concluded that C

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