Coal-water slurry

Coal, energy Coal-oil mixtures Coal-water slurry Gas turbine coal fuel Diesel coal fuel Fuel heneficiation, desulfurization... 

Figure 2.8. Schematic of Parker Hannifin atomizer designed for atomizing coal-water slurries and other difficult-to-atomize liquids. (Courtesy of Parker Hannifin Corporation, USA.)...

The Destec entrained bed gasifier is fed both a coal water slurry (stream 1) and a 95% pure... 

Coal-water slurry transport has been most thoroughly investigated and implemented. One of the earliest lines was 108 miles long, 10 in. dia, 50-60 wt % solids up to 14 mesh, at velocities of 4.5-5.25 ft/sec, with positive displacement pumps at 30-mile intervals. The longest line in the United States is 273 miles, 18 in. dia and handles 4.8-6.0 million tons/yr of coal it is described in detail by Jacques and Montfort (1977). Other slurry pipeline literature is by Wasp, Thompson, and Snoek (1971), Bain and Bonnington (1970), Ewing (1978), and Zandi (1971). 

The first way is pipeline transport of concentrated coal-water slurry. It assumes that utilisation of coal particle distribution preparation and/or using the various additives can substantially increase mass concentration of coal-water slurry till 70-80 %. For example, Black Messa Pipeline realised in USA transports 4.8 million tons of coal per year over the distance 439 km from the colliery in North Arizona to power plant Mohave near the border of Nevada and California with mass ratio of coal to water about 1 1, without using any additives, [5]. Recently, in the USA, Italy, China, Russia and other countries several coal pipelines were already realised. Even Oil and gas should be effectively transported as hydrate slurries, [6],... 

Except traditional slurry transport of coal as coal-water slurry or coal-water fuel, pipeline transport of coal in hydrocarbons seems to bring some advantage especially for arctic areas. 

Ercolani D. (1986), Production plants and pipeline systems for Snamprogetti s coal water slurries, recent experience and current projects in Italy and USSR. In Hydrotransport 10, (A.P. Bums ed.), BHRA, p.19... 

In addition to coal, gasifiers can be used on a variety of feedstocks. Almost anything that will burn can be gasified. There are many types of gasifiers. Some are fluidized beds, and others are moving beds. The coal fed to the gasifier can be dry or a coal/ water slurry. 

T. ferrooxidans, in the laboratory shake-flask experiments and in a two-inch pipeline loop. The results indicate that about 80% pyritic sulfur removal was achieved with 10 to 25% coal/water slurry recirculating at 6 ft/sec. at room temperature in 7 to 12 days. 

The ASTM Corrosion Test procedure by Total Immersion Method requires that all specimens in a test series should have the same dimensions when comparisons are to be made. In these experiments, carbon steel was used representing the pipeline material. The coupons were cleaned, polished and weighed. Coal-water slurry, 10 to 40 weight percent, was used in the corrosion tests. For the coal-water slurry the intitial pH of the medium varied from 2.3 to 2.6 and the test series containing the nutrient media, the microorganisms and the inhibitors the pH varied from 2 to 2.5. Specimens were immersed in the reaction vessel maintained at a constant temperature of 86°F for 72 hours or the specified time. The coupons were removed, washed with deionized water, dried and weighed. The loss in weight of the specimen, before and after the test was attributed to corrosion. 

Corrosion Test Results The corrosion rates were determined using a 10 wt% to 40 wt% coal water slurry with 147 to 417 /m coal particles. The corrosion rates ranged from 1.223 X 10 IPY for Illinois //6 to 1.272 X 1(T2 IPY for Indiana 3 coal slurry consisting of 40 wt% each coal. 

The addition of T. ferrooxidans in salt medium at the desired concentration to the coal/water slurry increased the corrosion rates for both the coals tested. The corrosion rates for the 72-hour and 500-hour experiments in the presence of T. ferrooxidans in salt medium with 10 wt% slurry of Illinois //6 ranged from 4.2 X 10 3 ipy to 1.41 X 10 ipy, respectively. However,the introduction of up to 10 ppm of a commercial corrosion inhibitor, Calgon T G-10, inhibited the corrosion rates with Illinois 6 and Indiana 3 coals to very low levels approaching those obtained with the deionized water. Balck Mesa pipeline has used this corrosion inhibitor on a regular basis with very satisfactory results. 

About 80% pyritic sulfur removal has been achieved by microbial desulfurization of Illinois 6 and Indiana 3 coals using T. ferrooxidans in laboratory shake-flask experiments and in a two-inch pipeline loop. The 10 to 25 wt% coal/water slurry was recirculated at 6-7 ft/sec for 7 to 12 days at 70-90°F. Results also show that the rates of bacterial desulfurization are higher in the pipeline loop under turbulent flow conditions for particle sizes, 43 to 200/m as compared to the shake-flask experiments. It is visualized that the proposed coal slurry pipelines could be used as biological plug flow reactors under aerobic conditions. The laboratory corrosion studies show that use of a corrosion inhibitor will limit the pipeline corrosion rates to acceptable levels. 

Table III. Slurry Pipeline Desulfurization Coal/Water Slurry (10 vjt %) Illinois 6 Bituminous Coal (Delta Mine) (Thiobacillus ferrooxidans)...

Bomberger, D.R., "Hexavalent Chromium Reduces Corrosion in Coal-Water Slurry Pipeline. Materials Protection, Vol. 4, pp. 43-49, 1965. 

Coal-water slurry Coal particles slurried with water 50 Commercialized... 

High concentration coal-water slurry Wide PSD coal particles slurried with water and additives 75 Commercialized... 

High concentration ultrafine coal-water slurry Ultrafine coal particle slurried with water and additives 70 Under development... 

ConocoPhillips 2-step entrained flow Coal-water slurry o2 2.0 1.0 1350-1400 >98%... 

ECUST. 2005. Multi-injector coal water slurry gasification, http //icct.ecust.edu.cn/download/cwsg. pdf (accessed September 16, 2009). 

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