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/%.

Application of coal-water slurry on the rotary calcining kiln of pedgion magnesium reduction process

Energy saving has been an important concept in modern industry especially to the countries and regions with energy shortage such as China and Japan. Utilization of Coal-Water Slurry （CWS） can improve the burning efficiency of coal and reduce the pollutions of soot, sulfide and the nitride by burning lump coal directly. The CWS is a promising energy saving technique and the effectual substitute of oil. The study on the preparation and application of the CWS has made progresses in many aspects. The present paper studied the basal problems for applying the CWS on the rotary kilns during the calcining-dolomite process in the magnesium factory, summarized the key points for the application process of the CWS and gave the corresponding solutions.

Theoretical Models of Light Scattering Applied in Sizing Particles in Coal Water Slurry

Advantges and disadvantage of Mie scattering model and Fraunhofer diffraction model are discussed. The result shows that 1) the Fraunhofer diffraction model is simple in design and fast in operation, which is quite suitable for on-line control and 2) the intensity and energy distribution of diffracted light of both the Mie scattering model and the Fraunhofer theoretical model are compared and researched. Feasibility of using the Fraunhofer diffraction model to replace the Mie scattering model in measuring particles in coal water slurry is demonstrated.

Effects of pH on rheological characteristics and stability of petroleum coke water slurry

In this study, the effects of pH on slurrying properties of petroleum coke water slurry（PCWS） were investigated. The slurrying concentration, rheological characteristics and stability of PCWS were studied with four different types of additives at pH varying from 5 to 11.The results showed that the slurrying concentration, rheological characteristics and stability of PCWS all increased at first and then decreased with increasing pH from 5 to 11,and a pH of around 9 was found to be the most favorable acid–alkali environment to all these three slurrying properties. It was also indicated that only in a moderate alkaline environment can the additives be active enough to react with particle surfaces sufficiently to obtain good slurrying concentration and form a stable three-dimensional network structure, which can support strong pseudoplastic characteristics and good stability. An acid environment was a very unfavorable factor to the slurrying properties of PCWS.

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.

Life Cycle Assessment of Ultra-clean Micronized Coal Oil Water Slurry

Life cycle assessment is applied to assess the ultra-clean micronized coal oil water slurry (UCMCOWS) with SimaPro and the environmental impact of UCMCOWS on its whole life cycle is also analyzed. The result shows that the consumption of energy and products are increasing along with the deepening of UCMCOWS processing, UCMCOWS making and combustion are the two periods which have a bigger impact on eco-system and human health. As a new substitute of fuel, UCMCOWS merits to be utilized more efficiently and reasonably.

Characterization of coal water slurry prepared for PRB coal

Powder River Basin(PRB)coal,which accounts for over 40%of the coal consumed for power generation in the United States,was investigated for preparation of coal water slurry(CWS).The static stability and rheology of the CWS were characterized as a function of loading.The coal loading was varied from 30%to 50%and both ionic(sodium polystyrene sulphonate(PSS))and nonionic(Triton X-100)surfactants were employed as additives.The addition of PSS to PRB slurries was found to yield poor static stability.On the other hand,Triton X-100 was found to be an effective surfactant,reducing the sedimentation by more than 50%compared to the one without surfactant in 45%CWS.Adding Triton X-100 reduces the viscosity of the CWS for coal loadings of30%and 40%.Although the viscosities for coal loading of 42.5%and 45%are higher when Triton X-100 is added,the static stability is significantly better than for samples without surfactant.The highest coal loading for PRB slurry with acceptable viscosity for pumping is 42.5%.

Main Influencing Factors on Service Life of High Chrome Refractories for Coal Water Slurry Gasifiers

The main characteristics of high chrome refractories for coal water slurry gasifiers were introduced. The damage mechanism of the refractories was analyzed by observing the microstructure of the used high chrome refractories with the aid of SEM. The main influencing factors on the service life of the refractories were summarized.

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.

CORRECTION OF WALL SLIP EFFECTS AND RHEOLOGICAL MEASUREMENT OF HIGH CONCENTRATED COAL WATER SLURRY

Coal-water slurry, a ncw liquid fuel, began to appcar during the world-wide petroleum crisis in the seventies of this century. Its applications to substitute petroleum drew great attention on the investigations of its preparation, combustion and transportation, etc. The rheological behavior is an important quality index for the fuel. However, the conventional viscosimeters designed for true fluids are not suited to the high concentrated slurry due to the complicated rheological bchavior. A special viscosimeter of tube type was rcpresented, which was designed and set up by the authors for the measurement of the theology of high concentrated coal-water slurry and experiments were conducted with two kinds of slurries from P. R. China. In consideration of the wall sliD effects the correction of the experimental data were made.

Effects of fractal surface on rheological behavior and combustion kinetics of modified brown coal water slurries

The paper reports the effects of surface fractal structures on the rheological behavior and combustion kinetics of raw brown coal and three modified coal water slurries （CWSs）. The results show that the fractal structures and physicochemical properties of samples are dependent on various modification processes. The apparent viscosities of the coal water slurries increase with increasing surface fractal dimensions （D）, especially with decreasing shear rates. Fur- thermore, it has been proved that the ignition temperatures and apparent activation energies of modified CWSs are lower than that of raw coal water slurry. Compared with the traditional qualitative analysis of the effect of pore structures on CWSs properties, D can more efficiently indicate the quantificational effect of pore structures on the rheological behavior and combustion kinetics of CWSs.

Research on the Atomization Characteristics of UCMCWS──A Novel Diesel Oil Substitute

Ultra-Clean Micronized Coal Water Slurry (UCMCWS ) as a form or coal-based fuel can be used in place of oil in diesel engine, gas turbine and clean combustion. In laboratory UCMCWS has been made from ultra-clean coal with ash less than 0. 8%, with concentration of UCMCWS less than 55%, and with viscosity less than 600 mPa. s. A test rig of atomization with diesel oil nozzle has been made. A preliminary conclusion is that UCMCWS can be atomized as good as diesel oil in the working condition of diesel engine.

Determination of the desiccation behavior of clay slurries

The main objective of this study was to determine the desiccation behavior of clay slurries. A clay slurry with high water adsorption capacity(W_L = 180%,W_P 60%,W_s = 20) was used to determine the soil water characteristic curve(SWCC), shrinkage curve, and hydraulic conductivity. The last parameter was determined similar to the Instantaneous Profile Method using evaporation tests. Results indicated that the clay slurry had an air entry value(AEV) of 1000 kPa and a residual suction of 5000 kPa that occurred at the plastic limit and the shrinkage limit, respectively. The discrepancy between theoretical and measured shrinkage limit was due to the gradual increase in clay particle contact. Unlike soils, the saturated hydraulic conductivity varied by two orders of magnitude(4×10 ~10 m/s at 20 kPa to 3 x 10 ~12 m/s at AEV). The unsaturated k further decreased to 10 ~14 m/s at 6 x 10~4 kPa beyond which vapor flow took place.

Blended coals for improved coal water slurries

Three coal samples of different ranks were used to study the effect of coal blending on the preparation of Coal Water Slurry (CWS). The results show that by taking advantage of two kinds of coal, the coal concentration in slurry made from hard-to-pulp coal can be effectively improved and increased by 3%–5% generally. DLT coal (DaLiuTa coal mine) is very poor in slurryability and the stability and rheology of the resulting slurry are not very good. When the amount of easily slurried coal is more than 30%, all properties of the CWS improve and the CWS meets the requirements for use as fuel. Coalification, porosity, surface oxygenic functional groups, zeta potential and grindability have a great effect on the performance of blended coal CWS. This leads to some differences in performance between the slurry made from a single coal and slurry made from blended coal.

Improving slurryability, rheology,and stability of slurry fuel from blending petroleum coke with lignite

Petroleum coke and lignite are two important fossil fuels that have not been widely used in China. Petroleum coke-lignite slurry （PCLS）, a mixture of petro- leum coke, lignite, water, and additives, efficiently utilizes the two materials. In this study, we investigate the effects of the proportion （7） of petroleum coke on slurryability, rheo- logical behavior, stability, and increasing temperature characteristics of PCLSs. The results show that the fixed- viscosity solid concentration （COo） increases with increasing 7. The ~Oo of lignite-water slurry （LWS, ~ = 0） is 46.7 %, compared to 71.3 % for the petroleum coke-water slurry （PCWS, c~ --- i00 %）, while that of PCLS is in between the two values. The rheological behavior of PCLS perfectly fits the power-law model. The PCWS acts as a dilatant fluid. As decreases, the slurry behaves first as an approximate Newtonian fluid, and then turns into a pseudo-plastic fluid that exhibits shear-thinning behavior. With increasing ct, the rigid sedimentation and water separation ratio （WSR） increase, indicating a decrease in the stability of PCLS. When α is 60-70 %, the result is a high-quality slurry fuel for industrial applications, which has high slurryability （ω0 = 57-60 %）, good stability （WSR 〈 2 %）, and superior pseudo-plastic behavior （n = 0.9）.

Effects of the grinding process on the preparation and qualities of CWS

Two different grinding processes were examined to determine the effect grinding has on the quality of a CWS. A series of slurries was prepared from Australian (Au) and Chinese (YZ) coals. Both types of coal were ground by a Chinese (CUMT) and an Australian (JK) grinding process. The performance tests of the prepared CWS showed that fluidity of all slurries was acceptable. The concentration of the CWS from YZ coal ground by the CUMT grinding process was higher than when the JK grinding process was used. The highest concentration was 70.14% in this case. The concentration of the CWS prepared from Au coal by the JK grinding process was higher than when the CUMT grinding process was used. The highest con- centration in this case was 70.97%. These differences are caused by the particle size distribution devel- oped during the different grinding processes.

Research on RelationshipBetween the Wetting Heat and the Slurry-Forming Ability

The wetting heat and contact angle of sixteen coal samples were determined and the slurry-forming ability of coal were researched. Comparing the relationship of the wetting heat and contact angle with the slurry-forming ability or coal, the auther has found out that the slurry-forming ability of coal can be measured by the wetting heat.

Aggregating structure in coal water slurry studied by eDLVO theory and fractal dimension

Coal water slurry gasification is a main source of hydrogen in the developing hydrogen economy.Moreover,biomass and waste can be added,making gasification process greener.To expand the application of coal water slurry and gasification process,it is necessary to understand the micro-structure in this large particle suspension system.In this paper,the micro-structure in coal water slurry was studied by extended DLVO(eDLVO)theory and fractal dimension,which is used to explain the mechanism of stability in large particle suspension systems.The interaction between two coal particles was characterized from the interparticle potential and energy barrier based on the eDLVO theory.The rheology and stability between different types of coals are measured and explained by the aggregating structure and fractal dimension in coal water slurry.The results indicated that there would be an aggregating structure in high rank coals,due to the interparticle potential caused by the surface properties,but probably not in low rank coals.This aggregating structure can be described and characterized by fractal dimension.The aggregation of particles is the source of the stability for high rank coals,as the close-packed 3D network structure in large particle suspension can support coal particles from settling down.The results have demonstrated that the combination of the eDLVO theory and rheological measurement is an effective way to investigate the stability of large particle suspension systems.

关于黑龙江省水煤浆产业发展的建议

为促进黑龙江水煤浆产业发展,分析水煤浆产业发展现状,探讨进一步加快发展水煤浆产业的建议,如政府主导统筹协调发展,地方推动配套工程示范,坚定落实绿色发展战略,增加核心技术储备等。