Secondary Reformer Water Jacketing

[ADA]

Dear Friends.

Share your experiences with respect to benefits of Secondary Reformer water jacketting or painting in comparison with each other.

Regards

[lambertbrite77]

For Kellogg`s plants, the secondary reformer is usually water jacketed as part of a robust design to the effectiveness of the equipment in the following ways:
1. The jacket water acts as a protective layer to the pressure shell in the event of the failure of the insulation hot-face and a possible run-a-way temperature by evacuating these temperatures and dumping same through continuous stream of flowing water.
2. The jacket water provides additional safety of the equipment by ensuring that the depleting hot-face insulation are monitored via monitoring and trending of the skin temperature thermographics of the jacketed water.

Regards.

Lambert Brite.

[ADA]

Dear lambert Brite,

Thanks for your detailed reply.

Regards
Adnan

[teji009]

The advantages of external atmospheric water jackets are:

The shell temperature is maintained very close to the saturated steam temperature, even under abnormal heat input much greater than design. This follows from the fact that the boiling water heat transfer film coefficient is very high (over 2,000 Btu/(sq.ft.) (hr.)
(°F) ) in comparison with the internal fluid film coefficient likely to be experienced under any condition.

System design for thermal expansion is made simpler and more assuredly predictable. Metal temperatures run dependably lower than with air cooling, while thermal strains on attachments and abnormal hot zones due to non-uniform circumferential temperatures, are prevented.

Where metal deterioration might occur at higher than normal temperatures that are not serious otherwise, jackets may insure the desired control.

[pbaboo]

Secondary Reformer water Jacket.gif

The water jacket of secondary reformer is rare case. The use of jacket or paint depends on the temperature of shell of the secondary reformer. Its purpose is alarm the situation when shell temp increased beyond its design temperature. Generally the secondary reformer color is dark blue. High temperature Paint quality is very important. While in painted shell insulating refractory is used this does not allow the temperature to rise. The painted surface act as a uniform insulation while the water jacketing can cause temperature difference due some non-uniformity of water. The fad of colour shows the condition of refractory at that point means this is the alarm. In water jacketed vessels castable refractory is used in which shell can expose temperature above CS failure temperature. The temperature of the shell does not exceed the failure temp of Carbon steel.

[teji009]

Hi Prem,

Could you elaborate on non-uniformity of water? Maintaining the water level above the exposed heat exchange surface will provide the convective evaporative cooling and resulting equilibrium to maintain delta T at atmospheric conditions. Makeup requirements depicts a lot about the system Heat retaining ability and internal refractory and metallurgical conditions. Though very complex to pinpoint unless obvious from visual inspection.

[hppandya1234]

Hi
we operated 2 number old ammonia plants with Water jacket around secondary reformer.They were in operation for more than @38 years without any problem/unsafe situation or failure
Regards
H P Pandya