A THREE AXIS SEMI-TRAILER FOR STORAGE AND                         TRANSPORTATION OF CRYOGENIC PRODUCTS : 

                        BASIC FEATURES AND SPECIFICATIONS

                               
                                  Cryogenic Semi-Trailer being filled with liquid argon   

                                    An abstract from the article by:

                                           Voronin, I.B. ( Ukraine)

 

   

                                       INTRODUCTION

The consumption of low temperature ( cryogenic) technical gases – such as oxygen, nitrogen, carbon dioxide and argon – is constantly growing in Ukraine, Russia and other CIS countries.  These liquid gases are  carried to large consumers by special means of transport. For transportation of liquid  products of air separation  (oxygen, nitrogen and argon)  often special transportation cisterns are  used.  These cryogenic vessels have a long  exploitation life and  a great majority of them, produced long ago in the USSR, are still in use. Yet in a few years a serious problem  will arise. The possibilities to use old and second hand  cryogenic vessels of  Soviet make are over in all CIS countries. It is necessary to replace them with new vessels. What kind of vessels these should be ?

 

Of course, a good alternative is using cryogenic railways cisterns. But  a potential customer  for cryogenic products must have a special rail way terminal equipped with large volume cryogenic vessels for storage, cryogenic pipe lines , etc. Very few customers have the finance to create such a costly specialized infrastructure.

 

A universal solution of this problem is  to use  cryogenic Semi-Trailers for  liquid  technical gases as well as liquid natural gas  transportation and temporary storage. However, this technical solution was hampered by the absence in CIS countries of such  manufacturers who could offer  to buyers  locally  produced  Semi-Trailers with attractive ratio “ quality/price”. Now such a manufacturer has appeared. A  New Zeeland Company “Technex Limited” , jointly with the Ukrainian Association of Technical Gases Producers  “ UA SIGMA” has started in December 2007  a new  project of  Cryogenic Semi-Trailer assembly on the Ukrainian territory. Many suppliers of cryogenic equipment from many countries were invited to take part in the project.  Our Semi-Trailers have been certified in Ukraine and they are conforming to the

standards of CIS and other countries.

 

                      BASIC  FEATURES  OF SEMI-TRAILER

 

The outer body  of  cryogenic container is made of  carbon steel. The inner cryogenic vessel is made of  corrosion free  chrome-nickel alloy  austenite  steel. The container  “screen-vacuum” thermo insulation  consists of  many layers of aluminum foil between which there is a fiber glass laying. Vacuum inside the thermo insulation  is sustained  by special adsorbents laid at the bottom part of the container  at the  level of 5E10-3Pa. Very low temperature greatly increases the adsorbing effect. The instrument ware module is made of stainless steel and installed at the back side of the container. There are valves, control and measurement instruments, cryogenic centrifugal pump in this module.

 

The technological scheme of the container includes two important features : a liquid cryogenic product vaporizer ( to increase liquid gas  pressure inside the cryogenic vessel) and  a  cryogenic centrifugal pump.  The weight of cryogenic Semi-Trailer is 12 850 kg  if empty and 34370 when fully loaded. The volume of cryogenic vessel is

 19,59 m3.  The dimensions are – 12120x2490x3625 mm. The maximum pressure in the inner vessel is 8 Bar, at the outer  container –  is 1 Bar. Test pressure  of the inner vessel is 10,1 Bar. The leakage in both inner and outer vessels is checked by helium leakage seeker. The maximum weight of carried liquid oxygen is 20520 kg. To test daily loss of cryogenic products  a Semi-Trailer was filled with liquid argon and after covering distance of 1000 km.  the daily loss at summer time was  estimated at 0,4%.

 

At present  the Semi-Trailer is equipped with a cryogenic centrifugal pump, produced by  a French Company “Cryostar” ( max. capacity -400 liters per minute) but we plan to replace it with a higher capacity pump of ZP170/174 type, produced by “Fives Cryomec AG”( Switzerland) with a max. capacity of 400-600 liters per minute. 

The Semi-Trailer can be filled by two ways – directly from  a stationary cryogenic storage vessel or  by  its own cryogenic centrifugal pump. 

We have already sold the first Semi-Trailer produced by us and now  we are producing a few more Semi-Trailers at  orders from a number of other clients. .

 

                     
                       

                                    Conventional cryogenic cisterns of Soviet make

 

                     
                       

                                    Installation of thermo insulation

 

                     
                       

                                    After primary painting

 

                     
                       

                                    After final painting

 

                     
                       

                                    Control Instruments Module

 

                     
                       

                                    Semi-Trailer Technological Scheme

 

                     
                       

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