Yesterday, I got an opportunity to attend technical confirmation meeting with steam Boiler vendor. Unlike previous meeting with pump vendor, our senior chemical engineer and also our general manager of operation who are also chemical engineer, attended too.
Last time I had a curiosity to have full understanding about Boiler, its configuration, process philosophy, and manufacturing philosophy. Attending this meeting was one of free learning to understand those issue. At least it stimulated my curiosity again.
As the basic knowledge, we need to understand what the function of Boiler is. It is a vessel used to produced steam. Steam exits the boiler and used in various processes or heating application. In my project, steam produced by boiler will be used in the main processes (at the point which heating is required) and used to heat Marine Fuel Oil (MFO), which is very difficult to flow unless at hot condition.
Boiler unit usually consists of:
- Deaerator. Demin water from Water treatment plant is fed into deaerator vessel. The function of deaerator is to remove oxygen from boiler feed water. Oxygen need to be removed from feed water because it is the main cause of corrosion in boiler feedwater tank, feedlines, and also at boiler. If carbon dioxide also presents in the feed water, the rate of corrosion will increase due to low pH. Based on this site, oxygen removal from boiler feed water is achieved by breaking the water into small droplets and surrounding these droplets with an atmosphere of steam. This releases dissolved gas which will be vented with excess steam.
- Fuel tank. Fuel tank is used to store fuel for burner
- Boiler blowdown. The function of boiler blowdown is to control solids in the boiler water. During operation the concentration of solid builds up.
In the technical meeting, we asked several questions, concerning the configuration of the package on P&ID. There was a chemical dosing pump which will intermittently supplies chemical into Feedwater tank. We wondered what chemical was. I thought the chemical was acid/caustic to control pH of feedwater at pH 8.5-9 where carbon dioxide is completely removed.