Simulation Research on Coal-Water Slurry Gasification of Oil-Based Drill Cuttings Based on Fluent

In this paper,based on Fluent software,a five-nozzle gasifier reactor was established to simulate the gasification process of oil-based drill cuttings coal-water slurry.The influence of concentration and oxygen/carbon atomic ratio on the gasification process of oil-based drill cuttings coal-water slurry was investigated.The results show that when the oxygen flow is constant,the outlet temperature of gasifier decreases,the content of effective gas increases,and the carbon conversion rate decreases with the increase of concentration;When the ratio of oxygen to carbon atoms is constant,the effective gas content rises and the temperature rises with the increase of the concentration,and the carbon conversion rate reaches the maximum value when the concentration of oil-based drill cuttings coal-water slurry is 65%;When the concentration is constant,the effective gas content decreases and the outlet temperature rises with the increase of the oxygen/carbon atom ratio,and the carbon conversion rate reaches 99.80%when the oxygen/carbon atom ratio is 1.03.It shows that this method can effectively decompose the organic matter in oilbased drill cuttings and realize the efficient and cooperative treatment of oil-based drill cuttings.

A Gasification Technology to Combine Oil Sludge with Coal-Water Slurry:CFD Analysis and Performance Determination

The development of more environment-friendly ways to dispose of oil sludge is currently regarded as a hot topic.In this context,gasification technologies are generally seen as a promising way to combine oil sludge with coal–water slurry(CWS)and generate resourceful fuel.In this study,a novel five-nozzle gasifier reactor was analyzed by means of a CFD(Computational fluid dynamic)method.Among several influential factors,special attention was paid to the height-to-diameter ratio of the gasifier and the mixing ratio of oil sludge,which are known to have a significant impact on the flow field,temperature distribution and gasifier performances.According to the numerical results,the optimal height-to-diameter ratio and oil mixing ratio are about 2.4:1 and 20%,respectively.Furthermore,the carbon conversion rate can become as high as 98.55%with the hydrolysis rate reaching a value of 53.88%.The consumption of raw coal and oxygen is generally reduced,while the effective gas production is increased to 50.93 mol/%.

A novel 3-layer mixed cultural evolutionary optimization framework for optimal operation of syngas production in a Texaco coal-water slurry gasifier

Optimizing operational parameters for syngas production of Texaco coal-water slurry gasifier studied in this paper is a complicated nonlinear constrained problem concerning 3 BP(Error Back Propagation) neural networks. To solve this model, a new 3-layer cultural evolving algorithm framework which has a population space, a medium space and a belief space is firstly conceived. Standard differential evolution algorithm(DE), genetic algorithm(GA), and particle swarm optimization algorithm(PSO) are embedded in this framework to build 3-layer mixed cultural DE/GA/PSO(3LM-CDE, 3LM-CGA, and 3LM-CPSO) algorithms. The accuracy and efficiency of the proposed hybrid algorithms are firstly tested in 20 benchmark nonlinear constrained functions. Then, the operational optimization model for syngas production in a Texaco coal-water slurry gasifier of a real-world chemical plant is solved effectively. The simulation results are encouraging that the 3-layer cultural algorithm evolving framework suggests ways in which the performance of DE, GA, PSO and other population-based evolutionary algorithms(EAs) can be improved,and the optimal operational parameters based on 3LM-CDE algorithm of the syngas production in the Texaco coalwater slurry gasifier shows outstanding computing results than actual industry use and other algorithms.

Effect of the benzene ring of the dispersant on the rheological characteristics of coal-water slurry:Experiments and theoretical calculations

In this study,low-rank coal-water slurry(LCWS)was prepared using polyoxyethylene dodecylphenol ether(PDPE)and polyoxyethylene lauryl ether(PLE),respectively.A combination of experiments and simulations was used to investigate the pulping properties and microscopic mechanism of the LCWS samples prepared using the two agents,so as to explore the influence of benzene ring on the performance of dispersant.The results of the LCWS preparation experiments revealed that the pulp-forming performance of PDPE exceeded that of PLE.When LCWS concentration is 62%,64%,and 66%,the apparent viscosity corresponding to PDPE is 247.80,504.17,and 653.10 mPa·s,and the apparent viscosity corresponding to PLE is 548.10,1470.61,and 1549.98 mPa·s,respectively.The C_(1000)(When the apparent viscosity is 1000 mPa·s,the corresponding concentration of LCWS is defined as C_(1000))values of PDPE and PLE are 67.60%and 62.95%,respectively.In addition to the van der Waals forces and hydrogen bonds between the PDPE and/or PLE molecules and coal,the benzene rings of PDPE presentπ-πstacking effect with the aromatic rings of coal.That could facilitate and strengthen the adsorption of PDPE on coal,which would be conducive to further improving the dispersion of coal particles.The two dispersants have no significant difference in effect on the pyrolysis of LCWS.The simulation results indicated that the times for PDPE and PLE molecules to reach flat adsorption state on coal are approximately 290 and 565 ps,respectively.The self-diffusion coefficient(D)of the PDPE and PLE on coal is 3.16 x 10^(-6)and6.57×10^(-6)m~2/s,respectively,and their interaction energies with coal are 785.71 and 648.60 kcal/mol,respectively.The results of the simulation calculations demonstrated that PDPE adsorbed on coal easier than PLE,and its binding is more stable than that of PLE owing to theπ-πstacking effect,which is conducive to uniform dispersion of coal in solution.The simulation results confirmed the experimental results.

CFD simulation on the gasification of asphalt water slurry in an entrained flow gasifier

Gasification technology is suggested to utilize asphalt particles, which are produced in the heavy oil deep separation process of using coupled low temperature separation of solvent and post extraction residue. In this work, the asphalt particles were first slurried with water and then gasified to produce synthesis gas. The gasification process of asphalt water slurry in an entrained flow gasifier was simulated using a three-dimensional computational fluid dynamics （CFD） model based on an Eulerian- Lagrangian method. The trajectories and residence time of asphalt particles, and the reaction rates, gas species distribution, temperature field and carbon conversion in the entrained flow gasifier were obtained. The predicted results indicated that the asphalt water slurry was a good feedstock for gasification. Moreover, the effects of particle size, oxygen equivalence ratio, and mass content of asphalt particles on the gasification performance of asphalt water slurry were investigated. These results are helpful for industrial application of asphalt water slurry gasification technology.

Synthesis, characterization and application of a dispersant based on rosin for coal-water slurry

A rosin derivative and maleopimaric acid diethanolamide(MAD), was synthesized, characterized by FTIR and1 H NMR, and applied as dispersant for the coal-water slurry(CWS) prepared from Chinese Shenfu coal. The CWS application performance investigation shows that the MAD dispersant has better abilities in reducing CWS viscosity and stabilizing the slurry than a commercial dispersant—sulfonated naphthalene-formaldehyde condensate(SNF). The physicochemical property investigation of the two tested dispersants shows that the adsorption amount of the MAD at coal-water interface is much larger than that of SNF, and the MAD has better wetting property than the SNF on the coal surface. It indicated that the excellent capabilities of MAD are related to the adsorption mode of standing upright on the coal surface. Based on the above, the mechanism of dispersion and stabilization of the CWS prepared from MAD dispersant is presented.

Simulation analysis of ammonia distribution in methanol production from coal water slurry gasification

Aspen plus software was employed to simulate process. The system concludes gasification scrubbing system the opposed multi-burner gasifier （OMB） methanol production and purification shift system. The distributions of ammonia con- centration in streams were obtained. The study demonstrates that ammonium crystallization problem caused by ammonia ac- cumulation, and if the process has ammonia exports its concentration will greatly reduced and the ammonia salt problem will effectively alleviate. Aspen plus simulation is a useful tool strengthening the ammonia recycling use and reducing pollutant for improving water quality, maintaining stable production, emissions.

Effect of the high-power electromagnetic pulses on the reactivity of the coal-water slurry in hot environment

An effect of the high-power electromagnetic pulses onto the droplet of coal-water slurry inside the furnace was investigated.In contrary to the previously investigated laser-induced fuel atomization that occurs at the room temperature,the pre-heated(to 400 K)slurry becomes dry enough to prevent the explosion-like steam formation.Thus,fuel does not atomize and the ignition does not accelerate.Furthermore,the absorption of several laser pulses leads to evident sintering of irradiated surface with following increase of the ignition delay time for up to 24%.Variation of the pulse energy in range 48-118 mJ(corresponding intensity up to 2.4 J·cm^-2)leads to certain variation of the increase of ignition delay.The strong pulsed overheating of the coal water slurry which does not initiate the fine atomization of the fuel generally makes its ignition longer.

Artificial neural network approach for rheological characteristics of coal-water slurry using microwave pre-treatment

Detailed experimental investigations were carried out for microwave pre-treatment of high ash Indian coal at high power level(900 W) in microwave oven. The microwave exposure times were fixed at60 s and 120 s. A rheology characteristic for microwave pre-treatment of coal-water slurry(CWS) was performed in an online Bohlin viscometer. The non-Newtonian character of the slurry follows the rheological model of Ostwald de Waele. The values of n and k vary from 0.31 to 0.64 and 0.19 to 0.81 Pa·sn,respectively. This paper presents an artificial neural network(ANN) model to predict the effects of operational parameters on apparent viscosity of CWS. A 4-2-1 topology with Levenberg-Marquardt training algorithm(trainlm) was selected as the controlled ANN. Mean squared error(MSE) of 0.002 and coefficient of multiple determinations(R^2) of 0.99 were obtained for the outperforming model. The promising values of correlation coefficient further confirm the robustness and satisfactory performance of the proposed ANN model.

Off-design Characteristics of IGCC System Based on Two-stage Coal-slurry Gasification Technology

整体煤气化联合循环（integrated gasification combinedcycle,IGCC）机组在一定情况下处于非设计工况运行。为了研究IGCC系统变工况特性,采用ThermoFlex软件建立基于两段式水煤浆气化技术的200 MW级整体煤气化联合循环系统模型,主要考查燃气轮机负荷、整体空分系数Xas、大气温度、大气压力对系统性能的影响。研究结果表明,降低燃气轮机负荷或者提高大气温度系统效率均呈先升高而后降低的趋势。整体空分系数Xas增加,机组发电效率降低。大气压力对系统效率影响较小。上述条件下采用两段水煤浆气化技术,系统性能可以得到有效改善。研究结果可为采用两段式水煤浆气化技术的IGCC系统的设计、运行提供参考。

A comparative investigation of the properties of coal-water slurries prepared from Australia and Shenhua coals

Two coal samples of similar rank were chosen from Australia and China to investigate the differences in Coal-Water Slurry （CWS） made from them. The effect of ash content and particle size gradation on these properties was also studied. Different grinding times were used when grinding the two coals and particle size analysis of these ground coals was used to select samples with a ＂double-peak＂ particle size distri- bution. All the ＂double-peak＂ samples were used to prepare a CWS. The concentration, viscosity, fluidity, and stability of each CWS were measured. The results show that the properties ofa CWS prepared from a coal sample with a ＂double-peak＂ size distribution are better than those CWS prepared from samples with a mono-modal particle distribution. The ash content of Australian coal is 21.72g higher than the ash content of Shenhua coal. The highest coal concentration in slurry from the Australia coal is 11.01% higher than in CWS from the Shenhua coat. The fluidity and stability of the CWS prepared from the Australian coal are both better than the fluidity and stability of slurry prepared from Shenhua coal. High ash content in the Australian coal imnroves the nulning results of a CWS made from it.

Combustion and Sulfur-fixing Performance of Pulping Black Liquor Coal-water Slurry

The effects of adding pulping black liquor and other additives to coal-water slurry(CWS) on the sulfur-fixing performance of the resultant mixture(pulping black liquor coal-water slurry) were evaluated. The experimental results demonstrated that the ash content of the black liquor coalwater slurry decreased as the addition of pulping black liquor in the mixture increased. Nevertheless, the addition amount should be appropriately selected to ensure that the black liquor coal-water slurry had a moderate calorific value. Addition of black liquor improved the combustion performance of CWS by lowering the ignition point and stabilizing the combustion process; moreover, the sulfur-fixation ratio after combustion increased by 12 to 16 percentage points than that of CWS, and the content of high-melting-point salt in the ash from CWS after adding black liquor was low. The sulfur-fixing ratio of CWS after adding a sulfur-fixing agent was effectively increased by 25 to 30 percenatge points, but with compromise of the fluidity and stability of the CWS; thus, the addition amount of a sulfur-fixing agent should be optimized.

水煤浆气化过程中元素的迁移与富集特性

元素的迁移与富集特性对煤气化装置的长周期稳定运行有重要影响。本文运用X射线衍射、X射线荧光光谱分析等手段,对气流床水煤浆气化装置使用的煤及气化后的粗细渣进行了研究,发现Na、P、V、Ti等元素较容易在细渣中富集,Fe、Ca、Cr元素则容易在粗渣中富集。热力学计算结果表明,气化过程中V元素主要是以气态V2O_(3)或VO_(2)的形式存在;高温下S元素大部分以气态COS和H_(2)S等形式存在。在升温过程中Cr元素与Mg、Fe结合生成固相MgCr_(2)O_(4)、FeCr_(2)O_(4),1100℃后Cr元素较容易以CrO及Cr_(2)O_(3)形式存在于液态熔渣中。在管式炉中开展了弱还原性气氛实验,探究了温度对煤灰中元素富集的影响特性。结果表明,气化温度越高,Na、S元素易向气相富集,Ca、Fe、Cr元素易在熔渣中富集。

煤制氢装置气化炉协同处置“三泥”探讨

某炼厂拟将来自污水处理场的浮渣/油泥和活性污泥送至煤制氢装置气化炉协同处置,以实现“三泥”的资源化利用。其中浮渣/油泥设计处理量4.2万吨/年,活性污泥设计处理量2.1万吨/年。根据掺配比例实验结果,浮渣/油泥、活性污泥按一定比例混合后,与水煤浆的掺配比例不宜大于12%。根据测算,项目实施后,装置进出料变化不明显,改造后硫含量比改造前增加约24吨/年。浮渣/油泥、活性污泥掺烧后产生废渣量较之前增加约0.2万吨/年。可减少能耗折算成标油为882.18吨/年,减少碳排放量399.41吨/年,环境效益明显。

GE水煤浆气化装置灰水水质影响因素分析与控制

气化灰水可谓是水煤浆气化装置的“血液”,灰水水质超标会导致系统设备和管道腐蚀结垢,制约GE水煤浆气化装置的长周期运行,并严重影响污水处理的效能。对灰水pH值、硬度、碱度、悬浮物含量、浊度、氯离子含量、电导率、氨氮和COD等关键指标对水煤浆气化灰水系统的影响进行分析,并就各影响因素总结出针对性的水质控制措施,以提高气化装置运行的稳定性和经济性。

在硝基苯废水资源化利用过程中煤气化棒磨机设备的腐蚀

通过模拟现场工况的浸泡试验和电化学试验,研究了硝基苯废水再利用过程中煤气化装置棒磨机腐蚀的类型、影响范围、主要介质及腐蚀发生的边界条件。结果表明:将制浆水源更换为硝酸苯废水后,由于硝酸苯废水中含有亚硝酸根离子,棒磨机发生了严重的缝隙腐蚀而频繁失效;当硝基苯废水中亚硝酸质量分数小于30μg/g时,棒磨机65Mn钢衬板的缝隙腐蚀可得到有效控制;在棒磨机内部混合过程中亚硝酸根因发生化学反应而消失,棒磨机后续设备管道的缝隙腐蚀风险降低。

水煤浆气化烧嘴喷口和炉砖烧蚀性的优化及应用

水煤浆加压气化工艺中工艺烧嘴的设计需与煤浆投料负荷相匹配。国内某公司6.5 MPa水煤浆加压气化装置原工艺烧嘴设计煤浆处理量73 m3/h,因下游合成气的需求变化使装置负荷需大幅改变,新方案烧嘴要求能满足75%~125%范围的负荷调节。为了评估极端负荷工况对气化装置造成的影响,针对该厂运行工况,对原烧嘴和新方案烧嘴进行了气化炉全炉燃烧数值模拟。计算结果表明:新方案优化了烧嘴在低负荷下的端面烧蚀和高负荷下的冲蚀问题,改善了高负荷下炉砖筒体和锥底的温度分布,有利于缓解炉砖的冲蚀速率。新方案实际投用后兼顾了较高的气化生产效率和宽广的负荷变化范围,验证了计算的正确性。

水煤浆气化协同处理有机废物要点分析

以SE水煤浆气化技术的实践经验为样本,介绍气化装置以掺烧方式协同处理有机废物的基本要求,从基础研究、系统规划、工艺设计、安全与环保措施等方面阐述气化有机废物掺烧的工作要点。

气化灰渣分级分质利用研究与实践

针对行业内气化炉灰渣综合利用存在的问题现状,通过对灰渣进行研究,采用离心机+煤泥回用、灰渣筛分洗选和固废制砖工艺,对航天炉气化灰渣进行分级利用,在降低能源消耗的同时,实现了灰渣的资源化利用,可为同类企业绿色低碳转型提供参考。

气化细灰高碳组分和化工污泥与煤协同制浆研究

对气化细灰高碳组分和化工污泥与煤协同制浆进行研究,有助于气化细灰和煤化工污泥的减量化及资源化利用,可为开发煤化工固废与煤协同制备高质量气化水煤浆技术提供支撑。针对气化细灰高碳组分和化工污泥在与煤协同制浆过程中存在的煤浆质量差的关键问题,采用气化细灰高碳组分和改性化工污泥与煤掺混制浆,通过分析固废不同研磨时间和掺混比例对混合煤浆黏度、流动性、粒度分布、纳米CT技术和接触角的影响,揭示煤化工固废的掺入对煤浆性能的作用机制。结果表明,改性污泥和高碳细灰与煤直接掺混制浆,掺混量每增加1个百分点,煤浆浓度降低约0.3~0.7个百分点;通过细磨或超细磨则可改善改性污泥、高碳细灰对煤浆成浆浓度的影响,在相同条件下与不进行研磨的制浆工艺相比,细磨后的煤浆浓度提升0.3~0.4个百分点。由于细灰和污泥的加入而使制浆原料与水的接触角降低,成浆性变差,煤浆浓度降低;细磨后的细灰、污泥与煤之间形成粒度级配,超细颗粒包覆在粗颗粒表面而具有润滑的作用,从而导致研磨后的固废掺入对煤浆浓度的影响降低。