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Title: Investigation of low-cost LNG vehicle fuel tank concepts. Final report

The objective of this study was to investigate development of a low-cost liquid natural gas (LNG) vehicle fuel storage tank with low fuel boil-off, low tank pressure, and high safety margin. One of the largest contributors to the cost of converting a vehicle to LNG is the cost of the LNG fuel tank. To minimize heat leak from the surroundings into the low-temperature fuel, these tanks are designed as cryogenic dewars with double walls separated by an evacuated insulation space containing multi-layer insulation. The cost of these fuel tanks is driven by this double-walled construction, both in terms of materials and labor. The primary focus of the analysis was to try to devise a fuel tank concept that would allow for the elimination of the double-wall requirement. Results of this study have validated the benefit of vacuum/MLI insulation for LNG fuel tanks and the difficulty in identifying viable alternatives. The thickness of a non-vacuum insulation layer would have to be unreasonably large to achieve an acceptable non-venting hold time. Reasonable hold times could be achieved by using an auxiliary tank to accept boil-off vapor from a non-vacuum insulated primary tank, if the vapor in the auxiliary tank can be storedmore » at high pressure. The primary focus of the analysis was to try to devise a fuel tank concept that allowed for the elimination of the double-wall requirement. Thermodynamic relations were developed for analyzing the fuel tank transient response to heat transfer, venting of vapor, and out-flow of either vapor or liquid. One of the major costs associated with conversion of a vehicle to LNG fuel is the cost of the LNG fuel tank. The cost of these tanks is driven by the cryogenic nature of the fuel and by the fundamental design requirements of long non-venting hold times and low storage pressure.« less
Authors:
;  [1]
  1. Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.
Publication Date:
OSTI Identifier:
650247
Report Number(s):
INEEL/EXT--98-00214; GRI--98/0015
ON: DE98052559; TRN: AHC2DT04%%160
DOE Contract Number:
AC07-94ID13223
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Feb 1998
Research Org:
Lockheed Idaho Technologies Co., Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States);Gas Research Inst., Chicago, IL (United States)
Sponsoring Org:
USDOE Assistant Secretary for Nuclear Energy, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
33 ADVANCED PROPULSION SYSTEMS; 03 NATURAL GAS; PROGRESS REPORT; LIQUEFIED NATURAL GAS; FUEL SUBSTITUTION; VEHICLES; TANKS; DEWARS; CRYOGENICS; COST; COMMERCIALIZATION