Tube-bundle cooler

Emonts reported the operation of catalytic burners for hydrocarbons and methanol/ anode off-gas dedicated to fuel processing operations [555]. The burners were designed for thermal loads of up to 11.5 kW. Palladium catalyst deposited onto porous ceramic fibre was used for natural gas combustion. Only 0.5 g palladium was required for the burner, which was water-cooled by a concentric tube-bundle cooler mostly through radiation losses. At 11.5-kW power output, carbon monoxide emissions were below 10 mgkWh , while NOj emissions were around 2 mgkWh . The methanol burner worked with a platinum catalyst and showed lower NOj emissions of 0.4mgkWh. ... 

In a single aerial cooler tfe.-e mav be several fans and several tube bundles as shown in Figure 3-16, wl bay width, tube leng ... 

Air coolers often consist of two tube bundles in one frame with one set of fans. In this case one tube bundle may be adequate for the initial capacity, and the space where the other tube bundle would reside can be blocked off by sheet metal to prevent the air from bypassing the cooling section. The other tube bundle can then be purchased when more cooling capacity is needed. 

In a forced-draft air cooler, cool air is blown through the underside of the fin tube bundle. In an induced-draft air cooler, cool air is drawn through the underside of the fin tubes. Either way, road dust, dead moths, catalyst fines, and greasy dirt accumulate along the lower row of tubes. As the tubes foul, they offer more resistance to the airflow. However, note that... 

Loss of airflow through a finned tube air cooler bundle is a universal problem. The effect is to reduce the exchanger s cooling efficiency. To restore cooling, you might wish to try the Norm Lieberman method, which consists of reversing the polarity of the fan motor electric leads. The fan will now spin backward. Depending on the nature of the deposits, a portion of the accumulated dirt will be blown off the tubes— but all over the unit. Personnel observe this procedure from a safe distance. 

The best way to handle the nonsymmetrical flow problem described above is to make the pressure drops in both the inlet and outlet tube bundle headers very small, as compared to the bundle pressure drop itself. Many of my clients add additional tube bundles in parallel with existing air coolers. This helps at first, but they find that the long-term benefits are quite disappointing, because of high pressure drop in the new header lines. 

Figure 5.5 Typical plan views of air coolers (a) two fan bays with three tube bundles, and (6) one fan bay with three tube bundles.

Air coolers are usually 6 to 50 ft long. Tube bundle bays are normally 4 to 30 ft wide. Use of longer tubes tends to cost less as compared to using shorter, wider tubes. Tubes are stacked in horizontal rows. A two-pass tube bundle would have an equal number of tube rows dedicated to each pass, in which the top tube pass realizes a hotter air coming from the bottom section. Likewise, the tube bundle(s) can have multiple tube section passes, where each pass has the full count of tube rows in the air cooler. Here each tube bundle pass has a bottom-to-top tube row in the air cooler. (See Fig. 5.6.)... 

Step 6. In this step, the number of tubes NT is calculated. First assume a tube length L in feet, which conforms to the area of the respective placement for the new air cooler. Next calculate the width of the tube bundle using your assumed tube length. 

Finfan cooler tube-side pressure losses of 2 to 10 psi are common, and these losses seldom exceed 15 psi. Greater pressure losses indicate that more parallel tubes are needed and/or a parallel tube bundle is needed. 

The anodic protection technique now enables air coolers and tube bundles in sulfuric acid plants to be protected from corrosion reliably and economically. Anodic protection was provided for air coolers of sulfuric acid production plants for the first time in 1966. Since then, a combined cooler surface area exceeding 10,000 m in air-cooled and water-cooled sulfuric add plants has been protected in this way worldwide. The installed initial electrical direct current output of the potentiostats is >25 kW, corresponding to an energy requirement of 2.5 W/m for the surface needing protection (Kuron and Grafen 1988). 

Figure 16-1 shows a typical refinery water cooler. The cold water flows into the bottom of the channel head and then passes through the lower half of the tube bundle. The water makes a 180° turn in the floating head and flows back through the upper half of the tube bundle. The warm water exits from the exchanger through a nozzle located at the top of the channel head. 

The primary function of the lube oil console is to supply clean, cool lubricating oil to the bearings of the compressor and its driver. The console is a package of equipment, which is supplied by the compressor vendor and usually includes an oil reservoir, two pumps (a primary and a spare), two filters or filter elements in a duplex-type arrangement, coolers, and associated controls. A typical lube oil console is shown in Exhibit 4-20. When placing a iube oil console around a compressor, the designer must adhere to clearance requirements for operation and maintenance of the unit. First, there should be sufficient room to remove the cooler tube bundle. Second, the space required to pull the filter elements must be considered—there can be no physical obstruction over the filters that... 

Air cooler units are entirely different from the previously mentioned arrangements in that the cooling agent used is circulating air instead of a liquid As seen in Exhibit 6-9, an air cooler unit consists of fin-tube bundles with a header box attached to each end, supported horizontally by a steel frame or struaure. For the single-pass arrangement, the inlet nozzles are mounted on the top of the header box the outlet nozzles are at the opposite end and mounted on the bottom of the header box. For die double-pass arrangement, the outlet nozzles are located at the same end as the inlet nozzles. For additional surface area, more passes can be added or additional units can be... 

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