№ 1 (43) 2009
                                   Selected Abstracts  of  Articles

                     L I Q U I F I E D     N A T U R A L     G A S

  LNG/ LCNG Refuelling Stations for NGV (Natural Gas Vehicles):

 the best current   alternative to refuel vehicles and fleets

             The article contributed by Vanzetti Engeneering ( Italy)
                                   

                                Updated the 30th of January, 2009                                   

 

        LNG / LCNG REFUELING STATIONS

for NGV (Natural Gas Vehicles):

the best current alternative to refuel vehicles and fleets

                                              

Vanzetti Engineering, Italy based international leading designer and manufacturer of CRYOGENIC PUMPS and AMBIENT VAPORIZERS for LNG applications, is moving forward rapidly in the R&D of technologies and components for vehicle LNG applications. 

In the NGV market, two applications are assuring the continuous development of Liquefied Natural Gas: LNG to be compressed by pump, vaporized and refueled into gaseous storages on board (LCNG refueling stations) – LNG to be refueled into cryo-vessels on board (LNG refueling stations). 

       

                                 LCNG   REFUELLING   STATIONS

 

The LCNG stations (liquid to gas) refueling CNG vehicles bring out two main benefits:

- on the logistic side: the chance to increase the amount of CNG refueling stations, thanks to the great flexibility of LNG delivered by road cryogenic trailers;

- on the energy side: it is relevant to compare the consumption of the existing CNG stations (where gas is taken from the pipeline at a low pressure, then compressed up to 250 bar at the refueling station) and the LCNG stations (where LNG is compressed up to 250 bar by cryogenic pumps and gasified by ambient vaporizers). With a LCNG station, you get a 75% energy saving;

- talking about maintenance costs, it is expected a saving of 75%.

 Flexibility, reliability and improved energetic efficiency are achieved thanks to the introduction by Vanzetti Engineering of innovative modular pumping systems covering a very large range of sizes. They are attained by using also a tested basic pump unit, especially developed for assuring high efficiency and easier maintenance, installed in mono to triplex or to quintuplex version.

 For large sized Refuelling stations, the second innovative solution introduced by Vanzetti Engineering is the installation of a booster-pump (a submerged centrifugal pump) feeding the common suction line: in this way the efficiency and reliability of the pumps system get increased, allowing also an easy connection to all the types of stationary cryogenic storages.

         

                                   LNG   REFUELLING   STATIONS

 

The LNG stations (liquid to liquid) are designed for refueling with LNG the innovative vehicles already equipped with cryogenic tanks on-board.

These are the benefits of a LNG vehicle – equipped with cryogenic tank on-board – compared to a CNG vehicle – fueled with gas stocked on board into cylinders of 200bar:

- big reduction of weight and overall dimensions: a cryogenic tank on-board has the same size of a traditional diesel tank with LNG specific gravity of just 0,5 kg/liter;

- relevant increase of the equivalent fuel quantity stored on board, assuring the heavy vehicles with a large operational autonomy as the one allowed by diesel fuel;

- significant increase of vehicle range: no differences with the one allowed by diesel fuel;

- considerable power saving of the refueling stations, equal to more than 90% compared to the traditional CNG station;

  

The main component designed for the LNG Refueling Stations by Vanzetti Engineering is the dedicated ”LNG SUBMERGED PUMP, model “ARTIKA 2”, installed inside a vacuum insulated cryogenic tank.

This submerged pump (that can be used also as Booster pump, as described above) is hermetically closed without any dynamic seals (seal less cold end) and installed in a stationary cryogenic vessel, totally submerged in the cryogenic liquid. Under these circumstances, the pump can stay permanently in cold conditions, ready to start immediately at any time and no seal gas purge system is needed.

  

                           MULTI-PURPOSE REFUELLING STATIONS

 

By assembling in one Refuelling Stations both the refuelling systems above introduced – LCNG and LNG – Vanzetti Engineering is now proposing a Station that can refuel all the NGV vehicles. More in detail: the “classic” CNG vehicles equipped with gaseous storages on board, as well as “last generation” of LNG vehicles equipped with cryo-vessels on board.

Thanks to these modern accomplishments all the Natural Gas vehicles – including Ferries, fishing boats and so on - can be easily refuelled at Vanzetti Engineering Multi-purpose Refuelling Station.

 

                        INNOVATIVE MODULAR “LNG PUMPING SYSTEMS”

 

In order to respond globally to the needs of flexibility, reliability and energetic efficiency, Vanzetti Engineering has developed several innovative solutions in terms of components and applications.

Particularly, these goals are achieved thanks to innovative modular pumping systems covering a very large range of sizes and two basic pump units, already well tested, installed in mono to quintuplex version (VT-1 and VT-55).

Vanzetti Engineering has designed two models of dedicated reciprocating cryogenic high pressure modular pumps, named respectively VT-1 and VT-55, featuring excellent performances and easier maintenance. The two dedicated modular multi heads pumps (mono to triplex to quintuplex) cover a very large range of LNG applications.

VT-1 series, mono to triplex version, is able to cover a LNG flow-rate range from 3,6 to 55,8 liters/min – designed for discharge pressure up to 420 bar.

VT-55 series, mono to quintuplex version, with the headers working in parallel, a common shaft and an eccentric for each header, is able to cover the LNG flow-rate range from 20 to 260 lt/min - discharge pressure up to 420 bar.

 VT-1 and VT-55 main features are:

- simple design for a very easy cold end handling;

- light weight and reduced mass for faster cooling down of the pump and reducing the losses of gas;

- improved reliability and stress resistance obtained in the high pressure cold end part avoiding welded components.

- very easy maintenance: the piston seals are pre-assembled in a cartridge designed as

self-centering and for a periodical maintenance the operator needs just to remove the cartridge and insert a new one .

 
For more information about Vanzetti Engineering LNG components and applications:

VANZETTI ENGINEERING S.r.l.

Via Avv. Giovanni Agnelli 10

12033 MORETTA (CN) – ITALY

Tel: 0039 0172 815811

Fax: 0039 0172 815822

info@vanzettiengineering.com

www.vanzettiengineering.com