Air-to-Air Heat Exchanger Stabilized kiln operation Improved cooler vent system control Reduced power consumption Reduced filter maintenance
AI R - T O - A I R H E AT E X C H A N G E R
General description
MAIN FEATURES • Module design • Workshop quality • Replaceable wear inserts • Flexible design • No requirement of dilution air or water spray
The FLSmidth Air-to-Air Heat Exchanger is the proven method for handling clinker cooler excess gas. It improves plant operations and reduces operating costs by both cooling the hot cooler vent gas and by knocking dust out of the gas stream prior to entering the dust collector and the vent fan.
Principles of operation The exhaust gas from the clinker cooler is vented to the Air-to-Air Heat Exchanger where it passes evenly through vertical parallel tubes. Cooling is accomplished by forced convection from cross-flow fans moving ambient air over the outer surface of the tubes. The Air-to-Air Heat Exchanger reduces both the temperature and the dust loading of the excess gas to the dust collecting system, thereby lowering the gas volume to be handled and increasing the life of the filter bags. This also permits the vent fan to operate at reduced speed and corresponding lower power consumption. Typical 2-module Air-to-Air Heat Exchanger unit
During upset clinker cooler operating conditions, the Air-to-Air Heat Exchanger aids in the protection of the downstream equipment within the specified design temperature limits. This is accomplished without introduction of dilution air or water spray systems. In most cooler vent systems where there is no heat exchanger ahead of the dust collector, numerous problems are experienced with burning filter bags, unstable kiln hood draft control, and limited vent system capacity due to the introduction of dilution air. With the Air-to-Air Heat Exchanger, these problems are essentially eliminated.
Equipment description Each heat exchanger module consists of a bundle of carbon steel mechanical tubes assembled within a structural frame housing. The sides of the frame are enclosed to facilitate the proper flow of the cooling air over the tubes. The tubes are shop welded to upper and lower tube sheets, with intermediate tube sheets located between fan levels to guide the tubes. The lower and intermediate tube sheets are welded to the frame, while the inlet tube sheet floats to allow for tube expansion. At each tube inlet, a flared replaceable wear insert is provided to protect the tubes from the abrasive clinker dust entering the Air-to-Air Heat Exchanger. Cooling air is blown horizontally over the tubes by axial flow fans with manual adjustable pitch blades. Each fan is driven by a V-belt drive and motor mounted on the fan frame. The fan and motor assembly is mounted to and supported by the Air-to-Air Heat Exchanger frame. As an option, variable frequency drives may be provided on the cooling air fans for additional power savings.
Module construction details
The dust that drops out of the gas stream passing through the Air-to-Air Heat Exchanger is collected in a bottom hopper and transported out by a screw conveyor. At the discharge of the screw conveyor, a tipping valve minimizes false air intake before passing the dust to the subsequent conveying system.
Inlet manifold
Tube wear inserts
Workshop assembly of modules
Design flexibility The amount of heat exchange between the clinker cooler excess gas and the ambient air is a function of the tube surface area and gas temperature difference. Overall dimensions of a unit can be modified to fit virtually any arrangement by adjusting the tube bundle dimensions. The height, width, and depth are established depending on the desired temperature drop, the expected gas flow, and the tube size needed to provide optimum performance. In order to best serve new or existing system layouts, the Air-to-Air Heat Exchanger can be configured to allow the gas to enter from the side, top, or bottom.
Air-to-Air Heat Exchanger designs are also available for use in recirculating cooler vent systems or for hot gas recuperation layouts. Two-pass designs may be offered for special applications.
Top entry Air-to-Air Heat Exchanger
www.flsmidth.com Up-to-date addresses of worldwide subsidiaries and sales offices are available from our website
DENMARK
USA
INDIA
FLSmidth A/S Vigerslev Allé 77 DK-2500 Valby Copenhagen Tel:+45 36 18 10 00 Fax:+45 36 30 18 20 Email:
[email protected]
FLSmidth Inc. 2040 Avenue C Bethlehem, PA 18017-2188 Tel:+1 610-264-6011 Tel:+1 800-523-9482 Fax:+1 610-264-6170 E-mail:
[email protected]
FLSmidth Ltd. Capital Towers 180, Kodambakkam High Road Nungambakkam Chennai 600 034 Tel:+91 – 44-52 191234 Fax:+91 – 44-2827 9393 E-mail:
[email protected]
05-2006-HEAT EXCH
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