Mobile transport system, that can be carried by truck and parked in storage area, consists of an inner container capable of holding 363 kg of diborane and an external, dual refrigeration unit which uses liquid nitrogen and Freon-14

Stone, G. R.

English

NASA Technical Reports Server

CF4 Safety 
Valves 
Relief Valves 
LN 2 Supply 
Valves 
Transducer 
..._ 
CF 
September 1972	 B72-10277 
NASA TECH BRIEF 
Ames Research Center
	 -4r 
NASA Tech Briefs announce new technology derived from the U.S. space pro g ram. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Safe Transport of Diborane in a Dual Refrigerant
System - A Concept 
The problem: 
Diborane, B2H6, has valuable applications as a fuel 
for deep-space propulsion systems; however, it is dif-
ficult to transport, store, load, or dram in any appre-
ciable quantity because of its pyrophoricity, toxicity,
transferred to a storage tank and then piped to the 
point of use. The small capacity of the shipping con-
tainers precludes direct loading or unloading of space-
craft propulsion modules that have propellant loads 
in excess of 272 kg (600 lb). Additionally, a separate 
and high vapor pressure. At dry-ice temperature 
(194° K), diborane has a vapor pressure of 200 kN/m2 
(29 psia); storage of B 2H6 is therefore more hazardous 
than storage of subcooled liquids under helium), 
A system for safely transporting large amounts of 
diborane was required because current regulations 
permit shipment only in 18-kg (40-1b) containers 
packed in dry ice. When large quantities must be 
used, the contents of a series of small containers are
drain unit of at least 318-kg (700-1b) capacity is 
required for disposal of contaminated fuel, or transfer 
of fuel from one storage tank to another. 
The solution: 
A mobile transport system, that can be carried by 
truck and parked in a storage area; the system con-
sists of an inner container capable of holding 363 kg 
(800 lb) of diborane and an external, dual refrigera-
tion unit which uses liquid nitrogen and Freon-14. 
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resultinb from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19720000276 2020-03-17T03:28:48+00:00Z
How it's done: 
The suggested design for the transport and storage 
system is illustrated schematically in the diagram 
(fill-lines, vacuum systems, etc. are not shown). The 
system consists of two refrigerant tanks enclosed in an 
evacuated steel container with 80-mesh perlite as an 
internal insulator. The primary refrigeration tank 
contains liquid nitrogen (LN2) held at about 92°K 
by 310-kN/m2 (45-psig) backpresure relief valves. 
The secondary refrigeration tank holds Freon-14 and 
surrounds the diborane tank as a thermal shield to 
control temperatures over the range from solid to 
liquid diborane (92° to 156° K). 
In operation, a pressure controller compares the 
ullage pressure of the Freon-14 tank with the desired 
setpoint pressure (temperature) and opens or closes 
the LN2 supply valve to the refrigerating coil in the 
Freon tank as required to maintain the set vapor 
pressure. The setpoint dial is calibrated in temper-
ature units rather than pressure. In the vicinity of 
92°K, the change in saturation temperature is 3 de-
grees per psia (0.44 degree per kN/m 2) vapor pressure 
change; temperature control with an accuracy of 
±8° maybe possible. 
Liquid nitrogen at 92°K is above the freezing point 
of Freon-14; thus, Freon acts as a passive heat trans-
fer medium and thermal shield. For simplicity, LN2 
flow is by gravity only. Heat of vaporization is ab-
sorbed in the Freon tank at a temperature difference 
of about 85 0 ; the gaseous nitrogen then superheats to
139° K as it passes to the ullage coil and exhausts into 
the nitrogen tank vent line. 
Notes: 
1. The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: 
NASA CR-109833 (N70-27095), Prelaunch 
Operations for a Space Storable Propellant 
Module. 
2. See also Tech Briefs B72-10276 and B72-10278. 
3. No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B72-10277 
Patent status: 
No patent action is contemplated by NASA. 
Source: Gordon R. Stone of
General Dynamics/Convair Division
under contract to

Ames Research Center 
(ARC-10559) 
B72-10277	 Category 03


Safe transport of diborane in a dual refrigerant system: A concept

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