3 replies to this topic

[K J]

hello every one, hope everybody will be fine.

         I have observed this phenomena many times that in our hydrogen plant reformed gas waste heat boiler out let temperature decrease by 2-3 degree Celsius observed at every start up, as time proceed after start up this temperature rise slowly to 353 C but by any how (may be plant trip etc.) if further start up is taken and load normalized this temperature drops to 349.5 C not only that it remains same for many days at same reformer load. any body else has seen this phenomena, if yes what may be the reason.

Edited by K J, 19 March 2014 - 08:23 PM.

[aroon]

Please elaborate your problem correctly. Your statements are misleading. Diagrammatic representation will also be very useful to understand the issue.

[K J]

Thanks for reply,

         now my problem is that TI2191(HTS inlet) is showing 353.1C but when reformer trips and further start up is taken load is normalised as previous this temperature remain some what 349.5C and it gradualy increases further above 353C over period of 1 to 1.5 months gradualy. I have observed this phenomena 4-5 times. (though graphic is old)

[PingPong]

Without a process flow scheme or DCS screen print(s) of the system it is difficult for outsiders to understand the nature of the problem.

In a normal steam reformer the outlet temperature of WHB is temperature controlled via an internal bypass in the WHB, but in your unit there is no such control?

 

I assume this WHB and HTS is located in the same steam reformer unit that you posted about in the past. That unit did not have a temperature controller at the syngas outlet of the reformer heater and was basically operated on glorified handcontrol via a manually set fuel fired duty based on wrong heating values. Apparently the poor control philosophy extends also to the rest of the plant. You really should complain with the licensor about this.

 

You should realise that, if the WHB has no outlet temperature control, it simply does what its UA permits. A lower reformer outlet temperature results automatically in a lower WHB outlet temperature and lower HTS inlet temperature. Also the quantity composition of the syngas, notably its steam content, have an impact on the syngas specific heat and thermal conductivity, and thus on the performance of the WHB and consequently its outlet temperature.