heat exchangers


GEA backs German green initiative


GEA heat exchanger plays a role in German environmental engineering scheme


H


eat exchangers play an important role, not just in heating and cooling but also in emissions control. One example of such an application is the exhaust gas recirculation (EGR) cooler developed by GEA Heat Exchangers, which reduces a ship’s emissions.


The company is a member of Germany’s Blue Competence scheme, which is a campaign for more efficient and climate- friendly technologies run by the country’s engineering federation, the VDMA. A spokesman for GEA Heat Exchangers told Marine Propulsion that being part of that initiative is important for the company. The VDMA’s initiative is a good example of how industry can work together to deliver sustainable solutions, he explained. “Its efforts protect the environment with innovative technologies and safeguard the quality of life on our planet.” As a contribution to this goal, GEA Heat


Exchangers’ EGR cooler is designed to reduce NOx and SOx emissions from both two- and four-stroke marine diesel engines, although it has no impact on their efficiency. The high pressures and temperatures found in large diesel engines represent a


cooler, and corrosion from the effects of condensation in the exhaust gas. In addition, the cooler must operate at a high level of efficiency.


But the effort is worthwhile. The lower the temperature of combustion, the smaller the


proportion of NOx in the engine’s emissions, GEA Heat Exchangers pointed out. Its EGR cooler can reduce exhaust gas temperatures from as high as 700°C down to 50°C before the exhaust gases are


combustion air supply. Space can also be a constraint so the


GEA Heat Exchangers’ exhaust gas recirculation cooler


challenge for the structural design of exhaust emission control, the company said. Adding an inert gas – for example, by recirculating some of the engine’s already-burnt exhaust


– reduces the production of NOx as the rapid oxidation of fuel molecules is inhibited by exhaust gas molecules.


This effect can be improved by cooling the recirculated gas, but the cooler must withstand harsh conditions: a temperature gradient


of more than 600°C, system-


related pressure fluctuations, vibrations transmitted from the engine to the


Icebreaker gets new heat exchangers The Finnish icebreaker Sisu was


redelivered in October after a four-month overhaul to its sea water systems that included replacing 36 heat exchangers. The work was carried out by the Estonian shiprepairer SRC at its Tallinn yard. It also exchanged 1,400m of corroded


copper-nickel pipes for glass-reinforced epoxy alternatives and replaced lubrication oil filters, pumps and valves. The heat exchangers were supplied


by GEA Heat Exchangers and were fitted to the ship’s engines and generators, replacing


cooling systems that the company had supplied more than 35 www.mpropulsion.com years before. The new units are GEA F-tube coolers,


which are described as having great thermal performance in a small space. Their compact design is the result of the use of elliptical tubes with cross-sections that promote effective flow with low pressure drop. Rectangular fins are slid over these tubes, which are metallically connected to the core tube by dip galvanising. The slight air-side pressure drop results in low operating costs for the fans, the manufacturer reported. Sisu is part of the Finnish icebreaking and ice management company Arctia


The icebreaker Sisu has benefited from 36 new heat exchangers (credit: Andy Siitonen/Wikimedia)


Shipping’s fleet. A year earlier another Arctia


vessel, Urho, had its heat


exchangers replaced as part of a similar upgrading, which also included updating its electronics and automation systems.


Marine Propulsion I April/May 2014 I 87


unit is compact, made from temperature- and corrosion-resistant stainless steel. Its finned-tube system, embedded in the water passage structure, features newly-developed fin geometry. The fins reduce the collection of dirt and debris and create turbulence in the gas flow, which results in heat transfer over the entire surface, the company said. In its latest generation, GEA Heat


Exchangers has added a scrubber before the cooler to desulphurise the exhaust gas. This injection of water also significantly lowers the exhaust gas temperature to below 150°C before it enters the cooler enclosure. During the cooling process, however, only part of the scrubbing water evaporates, with the rest


hitting the finned-tube block at great speed. “The newly developed compact stainless steel finned-tube system is also sufficiently resistant to this impact,” the manufacturer reported. MP


fed back into the


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108