APEX Group is specialized in designing and manufacturing heavy-duty plate-type and tubular Heat Exchangers (see Fig. 1) for handling large volumes of gases for heat recovery and gas treatment applications. The operation principle consists in passing cold gases (e.g. air) and hot process gases (e.g. flue gas) through alternating parallel channels in cross or countercurrent arrangement.
In refineries, the heat exchangers are applied inter alia as air preheaters for fired heaters, which constitute the process heart of a refinery. The efficiency of the combustion process is greatly enhanced due to the pre-heating of the combustion air (see Fig. 2).
Quite often, the fluids contain corrosive elements (e.g. Vanadium or Sulfur) and extreme loads of particulate (soot, dust, metal oxides or ashes). In these cases, the operation of the heat exchanger could be challenging, as dry or wet particles in the flue gas have the tendency to agglomerate in the heat exchanger, which could result in plugging. Additionally, operating close to the acid dew point, the heat exchangers might face corrosion.
In the case study, the operation was shut down on an annual basis due to the constant plugging of the heat exchanger. A careful analysis and implementation of an adequate maintenance cycle helped to increase the continuous operating time of the heat exchanger.
After the replacement of the heat exchanger, we studied the effect of the particulates on our heat exchangers. The case study resulted in an improved design, as shall be demonstrated in our presentation. Join us on PRC Europe 2020 to find out more.