Q & A > Question Details
A boiler to produce low pressure steam
• Boiler has a rudimentary design. • Total volume is 1 m3
. • Check valve, pressure and level indicators are present. The check valve opens when the required pressure is achieved. It
can also be manually operated. • Mode of operation of boiler is unchanged- Half of the boiler volume filled with water, then fired. Steam builds up to the
required pressure. When the required pressure is achieved, check valve opens letting out steam. Once steam generation
begins, level of the water in boiler is maintained and continuous operation is achieved. • A flow measuring device is installed upstream to measure steam flow rate. • The start-up requires 352 seconds. • Due to severe clogging, boiler is swapped with a temporary one. The new boiler is double the size of the previous one.
The heat input rate and the check valve characteristics remain unchanged. • 400 seconds after firing the new boiler, it is observed that the pressure indicator is faulty. The level in the tank has shown
little deviation and the check valve has not opened. • What would be the most safe and efficient course of action? The boiler has emergency PRV, and is functioning at one
fourth of the pressure it is built to handle, and the maintenance of the clogged boiler will take 6 hours. If the issue with
the pressure indicator was diagnosed 1200 seconds after firing, with the check valve still being closed, would your
course of action have deviated from the previous one? If so, how?
22/02/2020 A: keith bowers, B and B Consulting, kebowers47@gmail.com
Discontinue firing, release all pressure and repair/replace 'check valve/PCV' and PI. Also remove, test, and confirm PRV is properly working and set appropriately for the vessel and piping.
Continued firing could result in catastrophic explosion and loss of life.