Water For Injection (WFI) Generation System Design for a Global CMO Biotechnology Facility for the Manufacture of mAb/Recombinant Protein
Challenge from the Client
A greenfield project to deliver a new $350m CMO biotechnology facility in Ireland required WFI to service both the upstream and downstream processing of three separate manufacturing suites.
Each manufacturing suite was designed with a dedicated WFI storage tank and distribution loop. Ahead of the storage tanks, WFI is generated for all three suites simultaneously. The challenge was to ensure the generation packages had the capability to feed all three WFI storage tanks when called for, as well as consideration for planned and unplanned maintenance and backwash/regeneration at the pretreatment skid.
The client has stipulated that n+1 redundancy must be considered in the generation equipment of all clean utilities.
Our Approach & Solution
Working collaboratively with the client and clean utility vendors, IPS engineers agreed upon a design solution that ensures complete redundancy in the WFI generation.
The original concept was to generate, store and distribute both purified water (PW) and WFI. After completing a cost analysis study, it was found to be economically viable to remove PW and increase the capacity of the vapor compression (VC) WFI stills. The WFI stills are now fed directly from the Pre-treatment Water Package without the buffer of a storage tank.
With the removal of PW, the demand for WFI increased. The team considered two options to meet this demand:
Option 1 - 2 x 17,000LPH WFI VC stills
Option 2 - 3 x 13,500LPH WFI VC stills
With the first of these options, if one of the WFI still were to go out of service, the remaining WFI still would not be able to meet the full demand of the facility. It was therefore decided to opt for option 2 as this would also allow for further expansion.
The design of the pretreatment water skid was also reassessed in order to ensure N+1 redundancy. Each WFI still is fed by a pretreatment skid, with each pretreatment skid having the capability to feed a second WFI still if required.
In order to ensure complete redundancy at the WFI stills and storage tanks, all three WFI stills have the capability to feed all three WFI storage tanks.
The WFI generation design includes the following:
- 3x pretreatment water packages, one assigned to each WFI still with the capability of feeding a second WFI still
- 3x WFI VC stills working in Duty / Assist 1 / Assist 2.
- 3x WFI storage tanks (one assigned to each manufacturing suite.)
Simplifying the pretreatment skid and the deletion of PW storage and distribution presents a potential cost saving of €428,000 per annum. This is based on the savings from the fixed operational costs, spreading the capital cost savings over 10 years and the increase in variable operational costs due to the increase demand of WFI. The design also allowed for an overall reduced footprint in the clean utilities technical space.