Boiler feed pump material for casing & impeller 1

[SA07]

Hi
We are replacing an existing Boiler feed pump of flow 21 m3/hr by 30 m3/hr. This is because we need more flow. The pump is in operation since 2015.

Flow 30m3/hr
Head 31 bar
Temperature 120deg C
Medium Boiler feed water pH 8.5-9.5 temp 120deg C

We have got several quotes. The quote of the OEM is 1.8x quote of other suppliers. Different suppliers have quoted different materials.
We are not designing a new boiler feed pump.
The OEM has quoted the following material:

Pump casing material CS WCB
Pump impeller material WCB MOC

Other supplier has quoted the following material:

Pump casing material EN-GJL-250
Pump impeller material Steel CrNi 1.4301

Can we use the materials (Pump casing material EN-GJL-250 Pump impeller material Steel CrNi 1.4301 ) for this boiler feed pump working at these conditions?

What material is recommended for the pump casing and pump impeller for a boiler feed pump at these operation conditions?

 

[mk3223]

May refer to API Code of the material selection for the BFW application, i.e. API-610 App.G & H.

IMO, to use the alternative material for the BFW operation, you may want to perform a MOC, involving the Mech Eng, O&M and Pump SME, and to get an agreement for the material change.

 

[MJCronin]

Randhir,

Trying to compare cast metal international codes and standards is a nightmare

But, this may help:

PUMP CASING

from :

http://www.iron-foundry.com/en-gjl-...JL-250 is a,castings made by Dandong Foundry.

Your EN-GJL-250 is a high material grade of grey cast iron in European standard EN 1561. It is also called cast iron GG25 in standard DIN 1691 by Germany and Austria.

Besides GG25 in standard DIN 1691, this grade is also equivalent to the following grades:

ISO 185 - Class 250
GB 9439 - HT250 in China
ASTM A48 - Class 35 in USA
UNI 5007 - G25 in Italy
UNF - FG25 in Spain
AS 1830 - T250 in Australia
NS11 100 - SJG250 in Norway
__________________________________________________________________________________________________________

WCB (UNS Code J03002) is covered by the ASTM A216 standard, which specification covers carbon steel
castings for valves, fittings, flanges and other pressure-containing parts for high temperature service and
the quality required for assembly with other castings or wrought steel parts by fusion welding. These
grades are all "cast" grades meaning they are made through "casting" which is a manufacturing process
where a liquid material is poured into a mold and allowed to harden..

https://www.castingquality.com/castings-picture/Casting-Material-WCB.pdf

Therefore, regarding the pump casing, you are comparing a cast iron with a cast steel.


PUMP IMPELLER

Stainless steel types 1.4301 and 1.4307 are also known as grades 304 and 304L respectively. Type 304 is the most versatile and widely used stainless steel. It is still sometimes referred to by its old name 18/8 which is derived from the nominal composition of type 304 being 18% chromium and 8% nickel.


Therefore, regarding the pump impeller, you are comparing a cast steel material with a cast stainless steel.

The cast stainless material is almost always more expensive than cast carbon steel ....

The most common material used in BFP impellers in heavy duty API applications is 12%. Stainless steel may not be the best choice ...

Pay particular attention to the condition of your existing old pump. Look carefully for cavitation damage on the first stage. This may swing your choice and convince your management.

Ultimately, your confidence in the pump choice is based on the reputation of the pump vendor.

Because in most plants, a boiler feed pump is a "mission critical" component, it is comsidered unwise to skimp on costs ..... despite what your MBA managers may be telling you

Please complete this thread and tell us of your ultimate decision and help educate others

Good luck ....


MJCronin
Sr. Process Engineer

 

[MJCronin]

These may also be helpful ....

https://www.scribd.com/document/164798363/buildingabetterboilerfeedpumpusingvespel-cr-6100

https://www.pumpengineer.net/webart... a,ideal for higher temperature applications.

https://books.google.com/books?id=J...q=boiler feed pump casing 12 chromium&f=false

MJCronin
Sr. Process Engineer

 

[SA07]

Thks a lot mk3223 & MJCronin for the info and links

 

[Sue Shu]

This is very low flow and low pressure BFWP so check out Grundfos CR/CRN. I think all 316SS or chrome steel will work.