Filter Technology & Gas CleaningAir / Air Heat Exchangers
For gas cooling
In heat exchangers heat from exhaust gas is transferred to cooling air. The most common type of heat exchanger is the air/air type which in most cases is operated in cross-flows or cross-counterflows. It is the ideal choice for dry exhaust gases. The gas to be cooled is led inside the pipe by inflow hoods and ambient air is used to cool it in the external cross-flow by means of axial fans. Air/air heat exchangers (one or several) can be used on both the exhaust gas side and the cooling air side depending on what the application requires.
The primary purpose of exhaust gas cooling is to adapt the gas temperature in line with whichever filter media are available at an economically viable level (ie: the defined filter inlet temperature) and as a result to reduce the exhaust gas volume flows that are to be cleaned. Therefore the initial focus is on economic measures.
Since significant quantities of energy are released during the process of cooling process exhaust gases however we also consider how to make our systems more environmentally friendly and take advantage of regenerative waste heat utilisation in our concepts. As an example cooling 100,000 Nm2/h of dry air by 100oC corresponds to a heat output of approximately 3.5 megawatts (MW).