Coke breeze

Low Temperature Carbonization. The Lurgi Sptlgas process was developed to carbonize brown coal at relatively low temperatures to produce tars and oils (Fig. 5). A shaft furnace internally heated by process-derived fuel gas (Spblgas) is used. The product can range from a friable coke breeze to hard lump coal depending on the quality of the briquettes used in the feed. The briquettes, made in normal extmsion presses, break down into smaller sizes during carbonization. 

Coke The grinding characteristics of coke vary widely. Byproduct coke is hard and abrasive, while certain foundry and retort coke is extremely hard to grind. For certain purposes it may be necessary to produce a uniform granule with minimum fines. This is best accomplished in rod or bah mihs in closed circuit with screens. Hourly capacity of a 1.2- by 3-m (4- by 10-ft) rod mill with screens, operating on by-product-coke breeze, was 8.1 Mg (9 tons), 100 percent through No. 10 sieve, and 73 percent on No. 200 sieve power requirement, 30kW(40 hp). 

The fuel flows at right angles to the air flow. Only a small amount of air is fed at the front of the stoker, to keep the fuel mixture rich, but as the coal moves toward the middle of the furnace, the amount of air is increased, and most of the coal is burned by the time it gets halfway down the length of the grate. Fuel-bed depth varies from 100 to 200 mm (4 to 8 in), depending on the fuel, which can be coke breeze, anthracite, or any noncaking bituminous coal. 

In the first reconstruction [27] of road slabs contaminated with CL, silicon iron anodes were embedded in a layer of coke breeze as shown in Fig. 19-4a or the current connection was achieved with noble metal wires in a conducting mineral bedding material. Slots were ground into the concrete surface for this purpose at spacings of about 0.3 m (see Fig. 19-4b). This system is not suitable for vertical structures. 

Fig. 19-4 Older anode system for roadway plates (a) Silicon iron anodes in coke breeze bed, (b) noble metal lead in conducting bedding in a trench.

An electrostatic precipitator is used to remove more tar from coke oven gas. The tar is then sent to storage. Ammonia liquor is also separated from the tar decanter and sent to wastewater treatment after ammonia recovery. Coke oven gas is further cooled in a final cooler. Naphthalene is removed in a separator on the final cooler. Light oil is then removed from the coke oven gas and is fractionated to recover benzene, toluene, and xylene. Some facilities may include an onsite tar distillation unit. The Claus process is normally used to recover sulfur from coke oven gas. During the coke quenching, handling, and screening operation, coke breeze is produced. The breeze is either reused on site (e.g., in the sinter plant) or sold offsite as a by-product. 

Grus, m, tk n. small fragments, smalls, fines specif., small coal, slack breeze fine gravel debris, -boden, m. soil from rock debris, -kakao, m. cacao hiisks. -kohle, /. small coal, slack, -koks, m. coke fines, coke breeze. 

Carbonaceous materials graphite, carbon, graphite chips, coke breeze, conductive polymer, conductive paint. 

Groundbeds consist of a carbonaceous extender generally coke breeze and graphite, silicon-iron scrap steel, platinised titanium or niobium anodes. 

Furthermore, the restrictions on operating voltage that apply to titanium in a marine enviroment are not always relevant to titanium in soils free of chloride contamination. Coke breeze is, however, an integral part of the groundbed construction and ensures a lower platinum consumption rate. However, for some borehole groundbeds, platinised niobium is preferred, particularly in the absence of carbonaceous backfill or in situations where the water chemistry within a borehole can be complex and may, in certain circumstances, contain contaminants which favour breakdown of the anodic Ti02 film on titanium. In particular, the pH of a chloride solution in a confined space will tend to decrease owing to the formation of HOCl and HCl, and this will result in an increase in the corrosion rate of the platinum. 

If all the oxygen produced were to combine with the carbon the maximum theoretical wastage rate would be of the order of 1 kg A" y However, in practice the rate is usually of the order of 0-2 kg A y and in coke breeze may be as low as 0-05 kg A" y ". In seawater, where chlorine is the predominant gas produced, to which carbon is immune, any oxygen formed will be quickly removed and the corrosion rate may be very low. 

Some typical properties of coke breeze and similar materials are shown in Tables 10.20 to 10.22. The densities given in Table 10.20 are for bulk material and are dependent upon grading. Flake graphite is not recommended for use in groundbeds as it tends to conglomerate and prevent gas emission. 

When coke breeze is tamped down the correct pressure to aim for is approximately 15 Nm" This will ensure integrity of the groundbed whilst in operation, remembering that it will be reducing in volume by chemical oxidation. A pressure of this magnitude will reduce the initial bulk resistivity of the coke. 

In practice resistivities between 0-08 and 0-29 ohm m have been recorded on coke breeze samples used in typical groundbeds. The effect of pressure on the measured value for resistivity of different coke samples has also been reported elsewhere ". The resistivity of bulk metallurgical coke is given as 0-024 ohm m with a slightly lower value of 0-020 ohm m at a pressure of 0-43 Nm whilst in calcined fluid petroleum coke at zero applied pressure the resistivity was 0 - 02 ohm m, which decreased to 0 - 002 ohm m when tested at an applied pressure of 1-31 MNm... 

Calcined petroleum coke breeze with a high fixed carbon content of 99% is used in deepwell applications. The material has a low particle size and, with suitable additives, may be converted into a slurry and pumped into a borehole. The sulphur content of this material is high (1 -4%), yet moisture (0-2%), ash (0-4%) and volatiles (0-4%) are low. The typical resistivity of this material is 0 -15 ohm m. 

Schutt reported that the coke breeze specification and conditions in which the mix is prepared are important factors in determining the optimum operation of the conductive cement mix, whilst further details on the coke breeze asphalt mix composition are given by AndersonConductive concrete mixes, with a polymer binder have also been developed as an anode system specifically for reinforced concrete cathodic protection systems . 

High- silicon/ iron Magnetite Steel Iron Cast iron Pb-65b- lAg Lead/ platinum Graphite Aluminium Zinc Coke breeze... 

Where anodes are installed in special backfill, two series resistances are present — anode to backfill and backfill to soil. In practice, and with coke breeze backfill, a single calculation based upon the dimensions of the backfill column and soil resistivity is satisfactory. 

Backfill the soil replaced over the pipe in the trench (general connotation). In cathodic protection, special backfills are packed around the anodes. These backfills are selected to lower circuit resistance of the anode for sacrificial anodes a gypsum/bentonite mixture is used, and for impressed-current anodes, coke breeze. 

Solid Anthracite coal bituminous coal lignite peat wood Coke charcoal petroleum coke breeze semi-coke (low-temperature coal distillate) pulverized coal... 

Low volatile bituminous coal and high volatile anthracite coal Subbituminous coal Lignite Coke and coke breeze Wood Bagasse (dry) 11.000- 14,000 9.000- 11,000 7.000- 8,000 12.000- 13,000 8.000- 9,000 7.000- 9,000... 

Hojanas Also called Siurin. An iron extraction process. Magnetite, mixed with carbon-coke breeze and limestone, is heated in a ceramic retort by passage through a tunnel kiln at 1,200°C. Used commercially in Sweden since 1911. See also DR. 

Transport Reactor Gasifier Coal (sub-bituminous), KY and IL No. 6, coke breeze LHV IGCC 26.8-64... 

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