Coal bunkers

Fig. 5. Diagram of large Lurgi Spblgas carbonization plant A, coal conveyor B, movable distributor C, coal bunker D, drying zone E, connecting shafts ...

Stores should be specially designed, constructed of non-combustible material, and located away from other hazards (e.g. brick coal bunkers are suitable for small samples, but purpose-built constructions with explosion-proof lights etc. are required for larger quantities). They should be designated No Smoking areas and be well labelled. 

A major activity at Maasvlakte Power Plant is the co>combu tion of biomass pellets that are produced from sewage sludge, waste wood (untreated wood) and paper sludge of the biomass plant in the direct vicinity of the power plant site. The biomass pellets are transported by conveyor bells to the power plant and are blended with the raw coal in the raw coal bunkers. In the new Environmental Impact Study many other "fuels" were also considered. The fuels can be subdivided into three categories ... 

Voss K H. New stowing material and raw coal bunkers in the coal mining industry. Glueckauf and Translation 1987 123 289-295. 

Coal feeders should have a nonsegregating distributor interfacing between the coal bunker and the stoker feeder. A coal scale is recommended between the nonsegregating spout and the coal bunker. A coal scale provides a method for tracking daily, weekly, or monthly coal usage. All modern coal-scale electronics provide for real-time usage in terms of coal rate per hour, which is useful for tracking efficiency. 

Ovens coal bunker Coal charging car Drop sleeves Gas collecting main Ascension pipe with heat shield Coke guide and door machine... 

The means by which the coal is mixed with the binder and the method of heating the mixture largely determines the quality of the final product. The dried coal leaves the dry coal bunker at a temperature of 30°C-80°C (85°F-175°F) depending on size of the bunker and the transportation distance. After the metered addition of the solid or liquid binder, the mixture is conveyed to a pug mill heated by superheated steam, where its temperature is raised to about 20°C-25°C (36°F-45°F) above the softening point of the binders. 

Bunker Fires. A fire in the coal bunker should be recognized at once as a serious danger to personnel and equipment. Steam or carbon dioxide may be piped in directly to covered bunkers and to the affected areas in open-top bunkers. If the hot coal is run through the fuelburning equipment, special care should be taken to feed uniformly, without interruption. 

COAL. Mainly carbon, containing also many organic compounds. A controlled field test indicated that aluminum alloys performed well when contacting various types of coal for 30 years. Aluminum alloys have been used for trucks, hopper cars, chutes, skips, cages, trolleys, pit props, and hand tools in the handling of coal. Aluminum liners have given satisfactory service in coal bunkers to assist in the flow of the coal. See also Ref (1) p. 130, (3) pp. 50, 221. 

The environmental results from the test bum showed that no permit requirements were violated. Con aring the baseline to the 20% tire (energy basis) cofiring test showed lead emission rates were 5% lower and particulate emissions rates were 28% lower. Based on the coal bunkered e last two days of the test at the 20% cofiring rate, the sulfur dioxide emission rate was 13.7% lower than the calculated expected value. Ohio Edison obtained a modification of its operating permit to include up to 20% of total boiler heat input from tires. At this rate, over three million scrap tires could be converted to electricity each year at the Toronto facility. 

For utihties, two types of storage are used. A small amount of coal in storage meets daily needs and is continually turned over. This coal is loaded into storage bins or bunkers. However, long-term reserves are carefully piled and left undisturbed except as necessary to sustain production. 

Thermally efficient calcination of lime dolomite and clay can be carried out in a multicompartmeut fluidized bed (Fig. 17-27). Fuels are burned in a fluidized bed of the product to produce the required heat. Bunker C oil, natural gas, and coal are used in commercial units. Temperature control is accurate enough to permit production of hme of very high availability with close control of slaking characteristics. Also, half calcination or dolomite is an accepted practice. The requirement of large crystal size for the hmestoue limits apphcatiou. SmaU-sized crystals in the hmestoue result in low yields due to high dust losses. 

Use enclosed conveyors and sieves for coal and coke handling. Use sprinklers and plastic emulsions to suppress dust formation. Provide windbreaks where feasible. Store materials in bunkers or warehouses. Reduce drop distances. 

Transfer tower Bunker conveyor Dust extraction Coal feeder Coal mills... 

Figure 17. Weak acid recovery plant used by Sachtleben Chemie (based on know-how of Bayer AG) a) Heat exchanger b) Evaporator c) Injection condenser d) Stirred salt maturing vessels e) Filter press f) Bunker for pyrites g) Coal silo h) Bunker i) Mixing screw unit j) Covered store for mixed filter cake k) Calcination furnace 1) Waste-heat boiler m) Cyclone n) Electrostatic precipitator o) Stirred tank p) Storage tank q) Pump r) Cooler...

Colloidal Fuel. It is a colloidal suspension of finely pul verized coal in a fuel oil. Such a mixt, although more expensive than coal, possesses the advantage (particularly useful for marine purposes) that it is more readily handled and permits more economical utilization of bunker space. The density of such a suspension is higher than that of fuel oil and it produces more BTU per cu ft than... 

Fig. 2.4 Weak acid recovery plant used by g) Coal silo h) Bunker i) Mixing screw unit j)...

Example.— Required the net operating cost per ton of a 400-ft. conveyor handling 60,000 tons of fine coal during 1,200 operating hours in the year. The conveyor to elevate the coal 24 ft. and distribute it by means of an automatic tripper over a bunker 60 ft. long. Power delivered at the conveyor drive commands a value of 3 cts. per horsepower. 

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