Use of waste nitrogen from air separation units for blanketing cargo and ballast tanks

Abstract

The present invention relates to the use of a primarily nitrogen containing blanketing agent from the air separation unit of a Gas To Liquids, Heavy Hydrocarbon Conversion, or Methanol Synthesis Facility on transport vessels. The primarily nitrogen containing blanketing agent is used to reduce corrosion, reduce product biodegradation and oxidation, control invasive species, and prevent fires and explosions by reducing oxygen content. Accordingly, the present invention relates to integrated processes for producing hydrocarbonaceous products and using a primarily nitrogen containing blanketing agent supplied from the process in shipping the products.

Description

FIELD OF THE INVENTION [0001] This application is a divisional of U.S. patent application Ser. No. 10 / 464,543, filed Jun. 19, 2003, the contents of which are incorporated by reference in their entirety, and is copending to U.S. Divisional patent application Ser. No. ______, filed Jun. 30, 2006, Attorney Docket No. 1005950-000920. [0002] The present invention is related to an integrated process for the production and transportation of hydrocarbonaceous products in transport vessels, and more particularly to an integrated process for the production and transportation of Fischer-Tropsch products in transport vessels.BACKGROUND OF THE INVENTION [0003] In the transportation of products, in particular hydrocarbonaceous products, by transport vessels, several problems are often encountered. These problems include product biodegradation, product oxidation, corrosion, transfer of invasive species, and fires and explosions. During transportation, the hydrocarbonaceous products may be subject ...

AI Technical Summary

Benefits of technology

[0017] In yet another aspect, the present invention relates to a transport vessel. The transport vessel comprises at least one cargo tank for holding a hydrocarbonaceous product selected from the group consisting of petroleum, a hydrocarbonaceous product from a Gas to Liquids Facility, a product from a Heavy Hydrocarbon Conversion Facility, methanol, and mixtures thereof; at least one ballast tank; at least one liquid nitrogen storage container for holding liquid nitrogen, wherein the liquid nitrogen is supplied from an on-shore air separations plant associated with a facility for preparing a product selected from the group consisting a hydrocarbonaceous product from a Gas to Liquids Facility, a product from a Heavy Hydrocarbon Conversion Facility, methanol, and mixtures thereof; and a system to use the liquid nitrogen to reduce oxygen content of an on-board tank.

[0018] In yet a further aspect the present invention relates to a primarily nitrogen containing blanketing agent. The primarily nitrogen containing blanketing agent comprises an oxygen content of less than 5 volume %; and a nitrogen content of greater than 90 volume % wherein the nitrogen containing blanketing agent is supplied from an on-shore air separations plant associated with a facility to produce a product selected from the group consisting of a product from a Gas To Liquids Facility, a product from a Heavy Hydrocarbon Conversion Facility, methanol, and mixtures thereof. The primarily nitrogen containing blanketing agent is used to reduce oxygen content of a ship-board tank. Preferably the primarily nitrogen containing blanketing agent also comprises an odorant.

Problems solved by technology

In the transportation of products, in particular hydrocarbonaceous products, by transport vessels, several problems are often encountered.

These problems include product biodegradation, product oxidation, corrosion, transfer of invasive species, and fires and explosions.

In particular, hydrocarbonaceous products are frequently exposed to a layer of water when stored in large storage vessels fuel tanks of aircraft and holds of tankers.

The microorganisms or microbes will grow mostly in the water phase, but when the hydrocarbonaceous product is disturbed during pumping or mixing, the microbes can be dispersed into the hydrocarbonaceous product and cause contamination.

When present in the hydrocarbonaceous product, microbial growth can present a problem for several reasons.

For example, hydrocarbonaceous products may become contaminated with microbes during storage or shipment and as a result of the microbes, become hazy or cloudy.

When contaminated hydrocarbonaceous products are used in an engine or equipment, the microbes and / or the sludge may decrease the efficiency of the engine or equipment or prevent it from functioning altogether, for example, by plugging filters.

In addition, growth of microorganisms, in particular anaerobic sulfate reducing bacteria, in hydrocarbonaceous products during storage or transport may create corrosive sulfur-containing acids and damage the vessels in which the products are contained.

This corrosion damage may lead to the need for eventual replacement of these large, expensive vessels.

The quantity of ballast water used in a ship can be quite large.

Even ships reporting no ballast on board may act as vectors for non-native life forms because the ballast tanks of such ships contain an unpumpable amount of residual ballast water.

These infectious organisms can create both a human health problem, and a health problem to native species in the receiving country.

However, as mentioned above, ballast water is typically needed to maintain essential operating conditions of a ship, and it may be dangerous to discharge ballast water before reaching a port.

Ships may be retrofitted to permit this exchange, but such retrofitting is very expensive.

Because the above methods are not as effective or efficient as ideally desired, other methods of controlling the transfer of life forms need to be proposed.

During transportation, the hydrocarbonaceous products may be subject to oxidation and the ballast and cargo tanks on the ship may be subject to corrosion.

Although environmentally friendly, Fischer Tropsch products can oxidize relatively rapidly when exposed to air.

Further, some of the products produced by the Fischer Tropsch process may be waxy, and these products are frequently are shipped at elevated temperature.

Shipping at elevated temperatures increases the tendency of Fischer Tropsch products to oxidize.

Corrosion on ships has been linked to several major disasters.

The French government found that corrosion was one of the strong contributing factors that lead to the sinking of this ship.

However, it is very difficult to coat all surfaces, and any uncoated surface can lead to problems.

During transportation of hydrocarbonaceous products on marine vessels, there is the potential of fires and explosions on the transport vessels.

While scrubbed gas is an inexpensive source of inert gas, the scrubbing system may not be completely effective in removing carbon dioxide, nitrogen oxides, and sulfur oxides.

Carbon dioxide in the scrubbed gas can lead to corrosion of tanks.

Finally, traces of sulfur oxides can be incorporated in Fischer-Tropsch products, thereby increasing their sulfur content and reducing their value as low sulfur fuels.

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