Session: Research Posters

Paper Number: 110470

110470 - A Comparative Study on Insulation Materials in Tanks for the Storage of Cryogenic Fluids in Fire Incidents 

The ongoing geo-political conflicts and the increasing need for the implementation of measures to improve the energetic system sustainability are increasing the importance of tanks for storing cryogenic fluids in the energy industry. The most common example of cryogenic tanks applications is the transport of natural gas and hydrogen in their liquid form (LNG and LH2 respectively) for which, considering the same transport volume cryogenic storage ensures significantly higher transport capacities with respect storage based solely on overpressure.

A common feature of all cryogenic transported fluids is that their condition must be maintained minimizing heat leaks from the environment as much as possible. This is achieved by the implementation of thermal super Insulations (TSI) systems based on e. g. multilayer insulations (MLI), perlites, and vacuum which have proven to be effective in applications. However, due to the relatively short period of use, the small number of documented incidents, and the still few investigations carried out in the field, the exploitation of such systems in the cryogenic fluids transport sector still suffers from insufficient knowledge about the course and consequences of incidents. Accidents involving collisions, fires and their combination are quite common in the transportation sector and may generate extraordinary loads on the tank and its insulation system, eventually leading to tank failure.

The present study focuses on the behavior of TSI in tanks when it is exposed to an external heat source representative of a hydrocarbon fire scenario. This may cause an increase of the heat flux into a tank by several orders of magnitude with respect to normal design conditions, thus inducing severe and in the TSI, causing the rapid release of flammable gas and even resulting in a Boiling Liquide Expanding Vapour Explosion (BLEVE).

For the study a test rig was developed that allows testing of TSI at industrial conditions and subsequent analysis of TSI samples. This test rig takes into account the typical double-walled design of tanks for cryogenic fluids with vacuum and an additional insulating material in the interspace. The fire conditions are simulated on one side of the double-wall by adjustable electrical heating elements. This process allows the implementation of repeatable heat flows of up to 100 kW/m². The other side of the double-wall is a fluid supported heat exchanger, which allows the simulation of cold or cryogenic conditions in the test rig, and to determine the heat flux through the double-wall. Thus, the test rig allows thermal loading and performance analysis of TSI samples at the same time.

In the paper, the results of diverse tested TSI are presented and discussed. As a result of this study, the list of advantages and disadvantages for the choice of tested TSI expands. Within the test, all samples degraded as a result of a hydrocarbon fire-orientated thermal load. Strong differences in the behavior of any insulation material over temperature, location, and time were observed. Additionally, the tested MLI insulations were significantly more resistant to their base materials. These results are relevant for the evaluation of accident scenarios and can thus contribute to the improvement of TSI and the development of emergency measures for the protection of persons and infrastructures.

Presenting Author: Frank Otremba Bundesanstalt für Materialforschung und -prüfung (BAM)

Presenting Author Biography: Frank Otremba is the Head of the BAM division “Tanks for Dangerous Goods and Accidental Mechanics” in Berlin and honorary professor at the technical university of Brandenburg. He graduated as mechanical engineer (Dipl.-Ing.) and got his Ph.D. from University of Rostock in the field of numerical methods and fracture mechanics in 1991.

Authors:

Robert Eberwein Bundesanstalt für Materialforschung und -prüfung (BAM)
Aliasghar Hajhariri Bundesanstalt für Materialforschung und -prüfung (BAM)
Davide Camplese Alma Mater Studiorum - Università di Bologna
Giordano Emrys Scarponi Alma Mater Studiorum - Università di Bologna
Valerio Cozzani Alma Mater Studiorum - Università di Bologna
Frank Otremba Bundesanstalt für Materialforschung und -prüfung (BAM)