Wet-Process Cement

Rotary kilns operate at various temperatures throughout their length. A graph of approximate gas and charge temperatures for wet-process cement is shown in Fig. 12-67. The maximum charge temperature is 1700 to 1800 K for the gases, 1800 to 1925 K. Overall heat-transfer rates have been estimated to be in the range of 25 to 60 KJ/(s-m ) on the basis of total kiln volume. 

Wet-Process Cement Ball, tube, and compartment mills of essentially the same construction as for the dry process are used for grinding. Water or clay shp is added at the reed end of the initial grinder, together with the roughly proportioned amounts of limestone and other components. 

Burning wastes as fuel can have a significant economic impact on wet process cement production facilities, where fuel... 

A cement manufacturer using tires to supplement its primary fuel in a wet process cement kiln... 

In October, 1990, testing at Holnam/Ideal Cement, in Seattle, Washington, was performed at baseline (100 percent coal-fired), 11 percent TDF, and 14 percent TDF.12 Holnam is a wet process cement plant. The kiln emissions are controlled with an ESP. Particulate, SOz, NOx, VOC, and semi-volatile organic compound emissions decreased significantly from baseline for both 11 and 14 percent TDF use rates. CO emissions increased 30 and 36 percent,... 

Latent heat recovery on the smoke of wet process cement kilns is attained by means of a direct contact heat exchanger called AMAZONE. In this exchanger, water is running down in liqnid sheaths around textile cables. This water gets heated up and washes the dust away. 

At CIMENTS D OBOURG we are mnning two 3 000 tons per day wet process cement kilns. After the electrostatic precipitator, smoke temperatnre is between 120 and 150 deg.C. Its moisture content is about 0. 3 kg water per kg dry gas. Smoke enthalpy is thus about 1000 kJ per kg dry gas. Latent heat (about 850 kJ per kg dry gas) is six times higher than sensible heat. To recover this heat we need an exchanger which will condense the water vapour without getting clogged by hydrated kiln dnst. 

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