Boiler FAQ

General

Q

What temperature should the hotwell operate at?

A

By keeping the hotwell at the highest possible temperature the dissolved oxygen in the feedwater will be at the minimum. Dissolved oxygen in feedwater is one of the main reasons for corrosion in the water space. The remaining oxygen should be removed by chemical treatment. We suggest operating the hotwell at a minimum of 90 °C

 

Q

Is an Alfa Laval burner able to fire continuous on MGO?

A

Yes, as long as the correct precautions have been made. For boilers that were originally designed for operating on HFO with start up with MDO we strongly suggest upgrading the burner. Main concern is the low flashpoint and low viscosity of MGO. For further information please contact your closest AL office.

 

Q

What can be the cause of frequent misfires at start up?

A

The most likely reason for the misfires is too high back pressure in the boiler / uptake and that is usually caused by fouling in the convection section. We suggest cleaning the boiler (water washing or increased sootblowing). If frequent cleaning is required or if the problem of the misfiring persists we suggest to have one of our experts to re-adjust the burner.

Burner

Q

How often does a burner need to be adjusted?

A

We suggest having a burner re-adjusted once per year by a qualified engineer. Further re-adjustments might be required if the boiler shows signs such as black (or white) smoke from funnel, increased exhaust gas temperatures, fouling of the uptake, coke forming in furnace.

 

Q

Is it normal for unburnt oil to collect in the furnace?

A

No, unburnt oil or coke forming in the furnace/burner tip/ deflector is a clear sign that the burner is not correctly adjusted. This can be either the oil/air ratio, fuel temperature or bad atomization of the fuel or a combination of all.

Automation/Unisab

Q

What does the alarm “panel offline” mean?

A

the alarm is usually caused by a malfunctioning of the communication within the Unisab. The faulty Unisab needs to be replaced as without this communication the automation of the boiler is not functioning

 

Q

What does the alarm “oil servo error” mean?

A

The “oil servo error” alarm indicates that there is something malfunctioning in the oil loop. This can be a simple limit switch or a malfunctioning of the flow meter. Please check the full oil control loop for any failures

 

Q

What does the alarm “air servo error” mean?

A

The “air servo” error alarm indicates that there is a malfunction in the air supply to the burner. Please check the full air control loop for any failures.

 

Q

Is it possible to change a Unisab controller on board or is an Alfa Laval Engineer required?

A

Alfa Laval has a step by step guide for engineers on how to replace an Unisab controller. By following this guide, a competent engineer should be able to replace the controller. Please contact your local Alfa Laval representative for the guide.