Abgaswärmeaustauscher

Abgaswärmeaustauscher (Abgaswärmetauscher) sind Apparate, die speziell für die von Abgasen auf einen Wärmeträger konzipiert sind. Die Wärmeübertragung erfolgt mit einem Rohrbündel. Das Abgas kann dabei durch die Rohre eines geraden Rohrbündels geführt werden oder auch im Mantelraum um die Rohre. Die Entscheidung für die eine oder die andere Variante hängt schließlich von einer optimalen Strömungsführung und somit eines guten Wärmeübergangs, der Reinigungs- möglichkeit des Apparates sowie eines geringen Druckverlustes ab. 


Mit Hinblick auf die weiteren Komponenten in einer Abgasleitung, wie Schalldämpfer und Katalysator, darf der Gesamtdruckverlust laut Datenblatt des Motorenherstellers nicht überschritten werden. Eine deutliche Unterschreitung des zulässigen Druckverlustes führt dagegen zu einer signifikanten Erhöhung des Motorwirkungsgrades und kann das Ziel einer optimalen Anlagenauslegung sein. Denn dem größeren Motorwirkungsgrad steht der gestiegene Heizflächenbedarf und somit höhere Kosten des Abgaswärmeaustauschers gegenüber.


Ein Rohrbündelwärmetauscher kann vielfältig ausgelegt und an die speziellen Erfordernisse als Abgaswärmeaustauscher konstruiert werden. Als Wärmeträger werden Wasser, als  Heisswasser oder auch als Dampf, und verschiedene Wärmeträgeröle (Thermoöl/Thermalöl) genutzt, um die Abgaswärme des Motors für verschiedene Anwendungsprozesse nutzbar zu machen.

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Guest — Michaela
Hallo danke für den interessanten Artikel. Wir haben in der Firma auch einen riesen Wäreaustauscher mit Schalldämpfer der gerade ... Read More
Tuesday, 30 May 2017 11:29
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Service wird bei uns groß geschrieben - wir finden die individuelle Lösung für jeden Kunden

Als maxxtec-Kunde genießen Sie bei uns umfassenden Service. Auf unseren Kundendienst können Sie sich verlassen und zwar 24 Stunden täglich, 7 Tage in der Woche! Das bedeutet Anlagenlieferung, Einbau, Kundendienst und Reparatur aus einer Hand. Natürlich alles organisiert und zertifiziert nach ISO 9001.

 

Egal in welcher Branche Ihr Unternehmen tätig ist, gleichgültig wo Sie Prozesswärme benötigen, die Wärmeträgeranlage muss zuverlässig verfügbar sein - ganze Produktionsprozesse dürfen nicht unterbrochen werden. Wir stehen Ihnen mit unseren Serviceeinrichtungen rund um die Uhr, 7 Tage pro Woche, zur Verfügung! Ersatzteile liefern wir schnell und zuverlässig, alle wesentlichen Bauteile haben wir in unserem Lager vorrätig. Unser Service - prompt und kompetent - bietet für alle Situationen: Hot solutions for high demands!

 

Serviceleistungen und Sanierungen unabhängig von Hersteller und Baujahr sind bei uns an der Tagesordnung. Unsere erfahrenen Spezialisten beraten Sie gerne in allen Fragen der Anlagenmodernisierung. Wir bieten Ihnen ausgeklügelte Lösungen für maxximalen Erfolg.

 

Anlagenbetreiber kennen die Bedeutung vorbeugender Wartung. Gerade wenn Anlagen dauerhaft höchster Beanspruchung ausgesetzt sind und Verschleiß unvermeidlich ist. Regelmäßige qualifizierte Wartung und rechtzeitiger Austausch von Verschleißteilen, auch für Anlagen anderer Hersteller, sind das beste Rezept gegen teure Störfälle. 

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Preventive fire protection for heat transfer systems with organic media

Basically, heat transfer systems with organic media have a number of advantages compared to systems, which are operated with steam or hot water. However, of course there are also some drawbacks, for example the fact that organic media are generally flammable. That fact, under certain circumstances, can cause an increased risk of fire. 

 

In addition to direct fire hazard through the medium, the risk of damage by fire in the immediate vicinity has to be considered, which was not caused by the heat transfer system or in connection with this.

 

Considering these aspects, it must be ensured first, that a risk of fire, caused by the heat transfer system is prevented. Secondly, appropriate measures must be taken to minimize the consequences from fires, which can affect a heat transfer system with organic media.

 

Additionally, when selecting measures for fire prevention, it must be considered if it is a new installation or an existing one.

 

For new installations there are a number of solutions to reduce the risk of fire. Measures for fire prevention are for instance:

  • Use of permanent connections wherever possible (using welded fittings instead of flanged versions). Even more fundamentally is the use of hermetically tight bellows seals instead of conventional shaft seals in all kind of armatures.
  • Where flanged joints are unavoidable, high quality sealing materials such as graphitized soft metal seals have to be used.
  • Use of sealless pumps (magnetically coupled pumps) instead of conventional pumps with mechanical shaft seal.
  • Use of suitable and high quality welding methods TIG, MMA or, if on the basis of the applicable quality requirements permitted gas welding (autogenous).
  • Professional examination of the welding must be provided by experienced, certified welders.
  • Adequate control of the welding quality as by non-destructive testing (x-ray examination).
  • Use of suitable materials for all system components. 
  • Careful dimensioning and manufacturing of the heater.
  • Execution and documentation of leak and pressure testing before commissioning the system.
  • Consideration of visual control capabilities of all potential weak points such as: Plug connectors, rotary joints, shaft seals in pumps, flexible hoses, bellow expansion joints etc.
  • Inclusion of the thermal insulation in the safety assessment by making sure that flange connections are only insulated with such materials that do not allow penetration of heat carrier, for example Foamglas. If not permanent connections have to be isolated with other materials, a leakage control has to be possible in every case.
  • Installation of oil sumps with leakage monitoring as through appropriate liquid sensors under the pump and other critical components.
  • Installation of the "pumpmaxx" pump monitoring device for the early detection and reporting of leaks or other impermissible operating states of the pumps.

 

To reduce fire consequences, it is particularly necessary to avoid the subsequent flow of heat transfer oil into the fire. There are a number of ways to realize this:

  • Selective diversification of extensive heat transfer systems into zones which can be separated by means of suitable quick-acting shut-off valves.
  • Installation quick shut off armatures in the expansion system which can be operated from a safe distance to prevent the subsequent flow of heat carrier.
  • Reduction of the content of the expansion tank, for example, by using a level control system.
  • Installation of emergency - stop systems, which ensure that in case of fire, the pumps will be switched off quickly.
  • Installation of the heater in the open air, or in special boiler rooms to avoid risks for the workers or the facility.
  • For outdoor installation, maintaining a safety distance of at least 10m to all buildings (whose walls are not fire resistant) as well as to other installations. Alternatively, a fire wall can be built.
  • Design boiler rooms in such a way, that leaking heat transfer or fuel cannot reach the outside or to other rooms.
  • Avoid direct connections between boiler rooms and rooms which are frequented by people, as well as with staircases (Except for necessary staircases and rooms for boiler operators).
  • Arrange boiler rooms, in particular for solid fuels, not above the ground floor. Only boiler rooms for liquid or gaseous fuels can be located above of the ground floor when an escape of liquid fuels or the heat transfer medium is reliably prevented and the burner is equipped with a fan, so that smoke or exhaust gas cannot escape into the boiler room.
  • Make the dimensions of Boiler rooms sufficiently large.
  • Ensure that walls, columns and ceilings of boiler rooms are fire resistant and consist of non-combustible materials.
  • Make sure that doors in fire-resistant walls are at least fire retardant and self-closing (This does not apply to doors that lead into the open air)
  • Lead cables through walls and ceilings of boiler rooms only when the cables themselves can not transmit fire or when spread of fire is prevented by appropriate measures.
  • Build in separators for heat transfer media and liquid fuels in floor drains of boiler rooms.
  • In addition, of course, the local building authority guidelines must be followed.

 

In existing plants, of course, the above measures can be implemented only to a limited extent or at enormous expense. In such cases especially the preventive system maintenance and control has a determining importance.

 

One of the most important requirements for the safe operation of a heat transfer system is the tightness of the entire system. Therefore it is essential that at least once per month all sealing of valves, pumps and flanges are checked and tightened if necessary.

 

Furthermore, the maintenance of all the other components, in particular, the firing system, the fuel supply and the control cabinets is of considerable importance in the context of fire prevention.

 

In addition, the heat carrier itself must be analyzed at least once a year to ensure that the flash point is still within the acceptable range. If the flashpoint is lower than 130°C, low boilers must be removed from the system by cooking them out. After that procedure a re-analysis of the oil is required.

 

Throughout the year the monitoring of the heat transfer oil can be carried out for example by a "kontamaxx" system. With this measuring system, the essential characteristics of the heat transfer media can be continuously monitored and reported before the slightest deviations occur.

 

By using the Maxxtec "cleanmaxx" bypass filter system and various other systems e.g. a Maxxtec distillation unit, low- and high-boiling components can be removed from the heat transfer medium in a efficient and safe way. So the condition of the heat transfer medium can be improved, which of course, will significantly reduce the risk of unplanned disruptions or shutdowns.

 

If the condition of the heat carrier no longer allows to continue its operation in spite of the measures described above, the heat transfer medium must be replaced. In order to enable a long-term use of the new heating medium the system before the exchange, has to be cleaned by using an equivalent flushing oil.

 

Apart from the measures described above, of course, there is the possibility to trigger alarm in case of a fire with smoke detectors and other sensors. 

 

When using automatic extinguishing systems, the specific problems of burning heat transfer media must be taken into consideration in any case. 

 

An effective fire fighting with conventional sprinkler systems is not possible. Basically gas extinguishing devices can be used but such a system must be conditioned very carefully because of the oxygen poor atmosphere, which can cause a serious risk to people. 

 

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