Primary DI Water System
Description
The primary DI water system is located in Building 450 (APS Utility Building) and consists of pumps, heat exchanger, expansion tanks, and connections to the primary polishing system and make up water systems. The primary pumps circulate DI water, at a relatively low pressure (30 psig) through the primary water mains which feed water to the secondary distribution system. Each DI water primary/secondary interface occurs across a constant flow bridge which is manually preset for a given flow rate. After absorbing heat from equipment and friction the water is returned to the Utility Building where heat rejection takes place.
The pumping system consist of three (3) "end suction" type centrifugal pumps, each rated at 5,250 gpm at a differential pressure of 43 psi. The pumps are connected in parallel through a common 24 inch stainless steel pipe header. The system operates with two pumps running simultaneously and one pump held in reserve as standby. Subsequent to the completion of construction two (2) of the pumps were provided with variable frequency motor drives (vfd) to allow for control of the rate of water acceleration and deceleration to eliminate shock to the piping during pump starts and stops. With the availability of motor speed drives, advantage was taken of the systems new capability to regulate system pressure by connecting the drive controllers to a differential pressure sensor which maintains a preestablished system set point by varying pump rotational speed. Due to the addition of speed control of the two pumps the remaining third pump was designated as standby.
Water from the APS returns to the primary pumps and then flows thru four (4) plate and frame heat exchanger located downstream. The heat exchangers were designed to reflect 27.7 megawatts of heat from the DI water directly to the cooling tower water system using three (3) exchangers with the fourth held in reserve as standby. Tower water is supplied to the heat exchangers via a secondary tower water system which consists of secondary water pumps and three way mixing valves. Temperature control is achieved by modulating tower water temperature to the heat exchanger. After the completion of the construction of the Utility Building DI water system the cooling water temperature, for all accelerator and experiment equipment located in climate controlled spaces, changed from 90°F to 75°F. The system was then modified by interconnecting one heat exchanger to the chilled water system, creating a second stage of cooling to achieve a water temperature, leaving the utility building, of 73°F. The existing tower water secondary pump and associated piping were altered to divert the required amount of DI water for the second stage of cooling.
The primary water headers also contain two 6 inch taps for the diversion of 150 gal/min of water to and from the primary polishing system. This amount of water is continuously polished to remove stray ions and dissolved oxygen picked up by the water as it circulates throughout the system.
Description:
Primary piping mains - 24 inch (30 inch underground)
Primary process water pumps
3 Pumps - 200 HP each
Nominal flow - 5500 g.p.m. each
Supply pressure - 35 psig
Supply temperature - 75°F
Heat Exchangers
3 Tower to Process water heat exchangers
1 Chilled water to Process water heat exchanger
Nominal capacity - 4000 tons (7.6 MW)
Make-up System
Storage tank - 6000 gal
Make-up rate - 150 g.p.m.
Polishing
Rate - 150 g.p.m.
Filtration - 2 micron
UV light treatment
Vacuum degassifier - 4 foor diameter by 23 feet high
Mixed bed resin
Photos
Process Water Storage Tank and Pumps
Process Water/Chilled Water Heat Exchanger
and Pump
Primary Process Water Polishing System
Primary Process Water Monitoring Panel
Process Water Heat Exchangers
Vacuum Degassifier
Primary Process Water Pumps
