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Wednesday, July 17, 2013

SLUDGE INCINERATORS

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These are capable of dealing with waste oil, oily water mixtures with up to 25% water, galley wastes and solid matter from sewage plants. For reasons of economy, a means of heat recovery such as the small water tube boiler shown below is often fined


Homogeneous oil/water mixtures are supplied as a well dispersed emulsion to a rotary cup burner. Solid wastes are placed in a chamber next to the main combustion chamber, through a loading arrangement which prevents the doors being opened with the burner on. The solid waste goes through a slow burning process known as PYROLISIS, (slow and complete combustion at high temperature with low oxygen content).Dry ash has to be periodically removed. Solid matter from sewage systems can be homogenised with the oil/water mixture before being burnt as a mixture by the rotary cup burner.


Pyrolysis
Pyrolysis is a form of incineration that chemically decomposes organic materials by heat in the absence of oxygen. Pyrolysis typically occurs under pressure and at operating temperatures above 430 °C (800 °F). In practice, it is not possible to achieve a completely oxygen-free atmosphere. Because some oxygen is present in any pyrolysis system, a small amount of oxidation occurs. If volatile or semi-volatile materials are present in the waste, thermal desorption will also occur.
Organic materials are transformed into gases, small quantities of liquid, and a solid residue containing carbon and ash. The off-gases may also be treated in a secondary thermal oxidation unit. Particulate removal equipment is also required. Several types of pyrolysis units are available, including the rotary kiln, rotary hearth furnace, or fluidized bed furnace. These units are similar to incinerators except that they operate at lower temperatures and with less air supply.

Limitations and Concerns
Limited performance data are available for systems treating hazardous wastes containing polychlorinated biphenyls (PCBs), dioxins, and other organics. There is concern that systems that destroy chlorinated organic molecules by heat have the potential to create products of incomplete combustion, including dioxins and furans. These compounds are extremely toxic in the 

1 comment:

Axis Thermal Engineering Company said...

Some rotary kiln process using the pressurized air for initiating it's thermal process and also it reduces the cost of incinerators