1. 2K Cold Box Process Design
Vishy Ravindranath
LCLS-II 2 K Cold Box FDR
Mar 28, 2018

2. Outline Introduction Process Requirements 2K CB P&ID
2K CB Major Components:
Control Valves
2K CB Flowmeters
2K CB Relief Valves

3. Introduction LCLS-II (x1 CP) LCLS-II (1 CP) C1 2K CB C2 2K CBIB IB DB DB
C1 2K CB
C2 2K CB
L0, L1 & L2 L3
LCLS-II (1 CP)
37 CM: 1.3GHz, (x35) GHz (x2)
Single CP Operation
U-Tubes between Interface Boxes
Welded Interface

4. 2. Process Requirements:4K CB & 2K CB Maximum Capacity
2K CB Capacity (Ref: 2K CB Technical Specification, S001)
Mode
Flow [g/s]
Inlet Temp. [K]
Inlet Press. [mbar]
Outlet Temp. [K]
Outlet Press. [bar]
Max
215
3.5 27
< 30
1.2
Min
150
3.6 28
4K CB Capacity
Ref: 4.5K CB Technical Specification, LCLSII-4.8-CT-0284
Cavities
(2K)
Warm Shields
(35-55K)
Intercepts
(5-8K)
Liq.
4K CB Max Cap.
4.0 kW (200 g/s)
15 kW
1.30 kW
15 g/s
Linac Heat Load (Qo = 2.7E10)
3.7 kW (180 g/s)
1.39 kW
Max 2K Ref Cap. = 200 g/s
Limited by 4K CB Capacity
15 g/s Liq. : Provides additional margin for the Intercept and the Warm Shield Loads

5. 2. Process Requirements: Linac 2K Heat Load (Mass Flow)
Cryoplant Capacity = 4 kW
Operating Margin wrt Cryoplant Capacity of 4 kW (200 g/s)

6. 2. Process Requirements: Heat Loads & Pressure Drops
C1-2K CB
C1-4K CB
Line A
Line B
QDis
Heat Load and Pressure Drop compiled in LCLS-II-4.8-EN-0804-R0 “LCLS-II 2K Cold Box Process Analysis”
QDis
QCM
QCM

7. 3. 2K CB PID LHe Dewar Clean up return Safety Reliefs To 4.5K CBX
Sub-atmospheric pressure He gas from cryomodules returns to the suction of CCs and is compressed from ~ 27 mbar to 1.2 bar in the 2 K coldbox. The compressed gas returns to 4.5K coldbox through an U-tube.
For the test of 2 K CBX with LHe dewar, 4.5K cold vapor from LHe dewar is used to simulate the flow, with a 3 kW heater for controlling the helium temperature in the suction line.
A bypass line for the overall CC train is included for 4.5K standby operation mode and pumping down.
Safety valves are used for the protection of the 2 K coldbox, CC and process piping.
Pressure and temperature measurement are installed at the suction of each CC and on the discharge pipe.
A flow meter is installed in the discharge pipe of CCs for flow measurement and controlling of CC.
The 2K coldbox provides vacuum insulation for the cryogenic part of CCs and the cryogenic process piping.
Clean up and warm up piping are included.
Utility piping (Instrument air, cooling water and guard vacuum) are included.
CC Bypass
2K RET From LINAC CM

8. 3. 2K CB P&ID: Interfaces Int No. Interface Bayonet Size
Component Pressure Rating [psig]
Operating Temperature
He-504
CC5 Discharge
5-3/16”
75.1
4-300
He-505
CC6 Suction
He-506
CC6 Bypass
He-507
30K return from 2K Cold Box to 4K Cold Box
He-508
4K vapor supply from LHe storage dewar to CC1 suction
3-1/8”
83.2

9. 3. 2K CB P&ID: Interfaces Int No. Interface Connection
ComponentRating [psig]
Operating Temperature [K]
He-501
CC1 suction
10” pipe welded 45
4-300
He-510
Cleanup return
½” pipe weld
150
300
He-511
3 Atm He supply
1” pipe weld
GV-512
Guard vacuum
1” pipe weld
Vacuum-15
IA-513
Instrument air
He-515
Relief Valve Discharge Collector
3” KF Flange 15
CW-517
Cooling water Supply
2” pipe weld
100
CW-518
Cooling water return
~300

10. 4. 2K CB Major Components: Control Valves
Valve Tag
Valve Descr.
Valve Size NPS
Max Sizing Scenario
Req. Cv
Max. Cv
PV41500
Dewar 4K Supply
1.5
Pump Down
Mass flow = 300 g/s
Inlet Pressure = 1.25 bara
Inlet Temperature = 4.5 K 40 52
PV41212
2K Bypass 2
4K Linac Operation
Mass flow = 490 g/s
Inlet Pressure = 1.5 bara
Inlet Temperature = 4.7 K 43
PV41160
CC Discharge 4
Inlet Pressure = 1.2 bara
Inlet Temperature = 30 K
202
302
PV41565
PV41170
Control Valves are sized in accordance with Flow Equations For Sizing Control Valves - ANSI/ISA (IEC Mod)-2007.
2K CB Bypass Valve –PV41212 size was increased from 1” to 2” valve.
2” valve allows 9 kW of Ref. Capacity for 4.5K Linac Operation (with RF)
3. 2K CB Control Valve Data Sheet documented in JLAB Spec: S007, Technical Specs for LCLS-II Cryogenic Control Valves (PV41212 updated spec communicated to Valve vendor by JLAB)

11. 4. 2K CB Major Components: Flowmeter
Tag
Description
Size NPS
Throat Size
Max Sizing Scenario
∆P_cal (mbar)
∆P_FS (mbar)
F41200
CC Discharge 4
1.8
m = 260 g/s
P_in = 1.25 bara
T_in = 30 K 66
100
F41500
Dewar 4K Supply 2
1.2
m = 300 g/s
T_in = 4.5 K 38 50
Flows considered for the sizing are based on CHL-II 2K Cold Compressor Flow Data
The flowmeters are sized in accordance with : “Measurement of Fluid flow by means of pressure differential devices-Part 1: ISO (1991)”.
2K CB Flowmeter Datasheets documented in JLAB Spec: S010, Technical Specs for LCLS-II Venturi Flow Elements
280 g/s
CC mass flow
200 g/s
CC5 Discharge Pressure = 1.2 atm
CC5 Discharge Temperature
30 K 6K

12. 4. 2K CB Major Components: Relief Valves
2K Cold Box Safety Reliefs are designed to:
Adequately relieve the system and protect the process pipes/components within the 2K Cold Box against worst case failure scenarios.
Relief Valves mounted within Guard Vacuum Enclosure: (protected by parallel plate with 2 psig set pressure): Prevents contamination of sub-atmospheric process lines during normal operations
3. All reliefs vent into a common relief header which is routed outside the building to vent the gas in a safe manner
4” Relief Discharge Collector

13. “79222-P0001 2K Cold Box Relief Valves”
4. 2K CB Major Components: Codes for Relief Valve Sizing
Relief Valve Sizing Calculations documented in:
“79222-P K Cold Box Relief Valves”
Standards & References:
API 520 – Part I 2014, “ Sizing, Selection, and Installation of Pressure Relieving Devices on Refineries, Part I-Sizing and Selection”
CGA S “Pressure Relief Device Standards”
ASME Code Section VIII, Division I, Appendix 11, Mandatory Capacity Conversions for Safety Valves

14. 4. 2K CB Relief: Heat Leak Assumption
Node#
Nominal Pipe Size
Length
Surface Area
Heat Leak
[in]
[m]
[m2]
[kW] #1 2 9
2.4 #2 10 6 20 30 8 11 4
2 1/2 5 #3 #4 7
2.7 #5
2.0 3 #6
For 2K CB thermal relief valve sizing based on heat flux assumption of 1500 W/m2
“Safety Aspects for LHe Cryostats and LHe Transport Containers,” W. Lehman and G. Zahn, ICEC7, London, 1978 (Fig 7):
6000 W/m2 for cryostat with 10 layers of MLI (super insulation)
1300 W/m2 for cryostat 1” thick layer of MLI
2K CB process pipes have 60 layers of MLI

15. 4. 2K CB Major Components: Reliefs
Failure Scenario:
Loss of 2K CB Insulating Vacuum
Heat Inleak into Process Lines due to air condensation
Tag
Mass Flow [g/s]
Req. Orifice Size [in]
Sel. Orifice Size [in]
RV41500 79
0.18
0.29
RV41530
1340
0.80
0.92
RV41540
274
0.36
0.44
RV41550
133
0.23
RV41565 94
0.19
RV41560
136

16. 4. 2K CB Major Components: Relief Valve Vent Line Pressure Drop
Ins. Vac
ΔP = 6 psi
Seg#1: 3” relief discharge manifold
ΔP = 2 psi
Pr = 45 psig
ΔP = 1.4 psi
PL = 66 psia
= ( )
ΔP = 2.4 psi
Air Leak
Pv = 14.7 psia
Seg#2: 4” Parallel Plate Vent
Flow Rate = 2 kg/s
- All reliefs vent simultaneously
Pressure Drop in Vent Line (Back Pressure) = 6 psid
Differential Pressure on the Process Line = 51 psid
Cold compressor casing design pressure = 60 psid.
Seg#3: 6” Relief Header
ΔP = 0.4 psi
Vents to outside the Bldg.

17. Summary
The cold compressor design accommodates the anticipated variation in the heat load.
The design & interface requirements for the 2.0 K Cold Box have been identified on the P&ID.
Relief Valve calculations have been performed for the 2K cold box. The calculation details have been documented and reviewed
Detailed supporting calculation documents been developed:
Document No.
Title
Status
LCLSII-4.8-EN-0804
LCLS-II 2K Cold Box Process Analysis
Released
JLAB S007
Tech. Spec for LCLS-II Cryogenic Valves
JLAB S010
Tech. Spec for LCLS-II Venturi
Under Review
JLAB P0001
2K CB Relief Valve Sizing
2K Cold Box P&ID

18. Background
LCLS-II 2 K CBX FDR, Mar 9, 2017

19. Non Cryomodule-Heat Loads
Document No.
Title
LCLSII-4.8-EN-0804-R0
LCLS-II 2K Process Analysis
LCLSII-4.5-EN-0179-R2
Cryogenic Heat Load
LCLSII-4.9-EN-0299-R1
LCLS-II CDS Heat Leak Analysis

20. Line B Pressure Drop for LCLS-II (1CP)
11 m
50 m
30 m
Int. Box
107.5 g/s
107.5 g/s
Pressure Drop in Line B for LCLS-II Baseline ~ 4 mbar