Dual purpose intermodal tank container

Abstract

A dual-purpose tank container is provided, designed for transporting unrefined or refined fluid within the same internal space, eliminating unproductive deadheading. The tank container includes an inner tank in a frame, and outer insulation shell, the tank being equipped with at least one diaphragm so that a fluid, for example crude oil or diesel fuel, can occupy inner space without risk of contamination from a residual fluid. The high viscosity unrefined fluid can be almost completely drained using fluid draining channels present on the diaphragm surface, increasing transportation economy and eliminating any residual fluid pockets. At least one inlet present on the upper tank body supplies a solvent vapor/fluid to condition the space between the diaphragm and the tank wall, thereby preventing sticking of the diaphragm to the tank inner surface.

Claims

1. Intermodal tank container adapted to accommodate loading or unloading of unrefined and refined liquids at the same or separate times, comprising at least two compartments separated by flexible diaphragm, said diaphragm having: sufficient tensile strength to allow unloading a compartment of the at least two compartments with higher viscosity liquid using pressure applied from an opposite compartment of the at least two compartments; impermeable structure to avoid cross contamination; arrangement completely around an inside of the tank, forming symmetrical tank sections; patterned surface equipped with plurality of ridges with fine edges; said tank having its wall equipped with at least one inlet supplying solvent fluid for conditioning of a residuum between the diaphragm and the tank inner surface areas.

2. Intermodal tank container as set forth in claim 1 wherein said tank has a sediment tray on the bottom of a compartment.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0017] FIG. 1 is an example of cross sectional side elevation of an embodiment of the intermodal tank container, to provide context.

[0018] FIG. 2 is a simplified side view in the cross section of the multi-diaphragm version of the invention in two different stages of the transportation process. Top one is transporting refined liquid, the bottom one is transporting unrefined liquid.

[0019] FIG. 3 is an enlarged fragmentary view in the cross section of the tank diaphragm in contact with the tank wall.

DETAILED DESCRIPTION OF THE INVENTION AND ITS PREFERRED EMBODIMENT

[0020] The tank container frame has standard intermodal ISO container dimensions. This way it can be transported in different modes without additional requirements. The design respects weight restrictions, primarily for road transportation, whose complete scope is known to those skilled in the art.

[0021] The tank diaphragm 6 intersects the tank girth wise in the middle in case of single diaphragm tank (FIG. 1) or anywhere else in case of multiple diaphragm tank (FIG. 2). In the two compartment tank in the FIG. 1, the diaphragm copies half of the tank shape and can turn inside out into the other side of the tank when pressured by gas or liquid. The tank halves are both designed for different use. The left compartment is for unrefined petroleum, the right compartment is for refined petroleum. Unrefined petroleum can be very viscous and sticky, for example, extra heavy oil hardly flows in ambient temperatures. Therefore, the left compartment could be optionally equipped with a heating mechanism in the form of electric heating cables applied on the bottom of the tank compartment. There is also an option of a container tank without heating elements, but requiring additional dilution of the unrefined petroleum. The tank has an optional insulation layer within the space between tank wall 3 and second shell 9 formed from light composite material. When the left compartment, containing viscous crude oil, is being emptied, the diaphragm propagates pressure from injected gas or liquid pressured into the right compartment, thus pushing on the viscous fluid and accelerating the unrefined petroleum unloading process.

[0022] Each half of the tank has a loading/unloading single inlet/outlet on the bottom 7,10. Tank halves are further equipped with pressure relief valve 4 and excessive vacuum breaker valve 5. There is also a manhole 2 dedicated to each of the tank compartments for servicing of internal parts. An optional sediment tray 8, can be also present, for accumulation of unwanted precipitates during transportation.

[0023] In order to allow the emptied part to be almost completely drained of liquids, the diaphragm body 6 has a special patterned surface (FIG. 3), which forms draining fluid channels 13 even if fully pressed against the tank internal wall 3. These channels are designed to drain towards the inlet/outlet location 7 on the compartment bottom. Proper draining of liquids is essential for the economy of the whole transportation process.

[0024] Each compartment is also equipped with at least one injection/suction inlet/outlet 1 on the upper portion of the tank. Especially the compartment(s) designed for unrefined liquid, where high adhesivity of the residual liquid is expected, can benefit from multiple solvent vapour inlet 1 configuration, as shown on FIG. 3. A single inlet 1 is also possible in case of centered star shaped pattern on the diaphragm fluid draining channels. Utilization of the vapor solvent fluid supplied via inlet(s) 1 together with the function of drain channels 13 on the diaphragm surface is necessary for prevention of differential sticking of the diaphragm to the tank wall in very cold temperatures due to increased viscosity and adhesivity of the residuum. The transported unrefined liquid has expected viscosity of 2000 cP, which is about the same as maple syrup, at the point of unloading. The residuum present after unloading of the compartment can reach viscosity of 250000 cP or higher in very cold temperatures of Northern Alberta. The untreated associated adhesivity would represent serious risk for the integrity of the tank diaphragm.

[0025] The logistic system is designed to exert minimal implementation cost on its customers. In order to achieve such an objective, it needs an element which supplies fluid transfer function. This is achieved using intermodal containerized pumps for fluid loading or unloading to and from the intermodal tank container. As the pump container is itself intermodal, it can be transferred together using the same means as the intermodal tank container. The pump container consists of two pumps, each one can supply loading or unloading functions according to a situation. There is also a dedicated small solvent vapor fluid pump for priming of the tank diaphragm patterned surface at the end of the unloading process. A nitrogen generator installed to supply sufficient flow of nitrogen gas needed for cooling or preparation of an inert environment inside the container tank, is also present. The intermodal pumps are both equipped with a flexible hose which, at best, automatically connects to the close sidewise positioned intermodal tank container inlet valve 7,10. This connection process can be also achieved using a telescopic bridge automatically governed from the inside of the pump container. Once the fluid flow channel is established, the fluid transfer process can begin. At best, the unloaded fluid present in the first tank compartment being unloaded by the first pump is pushed against the outlet on the bottom of the tank with help of the diaphragm 6, which is itself being pushed by the incoming fluid loaded into the second tank compartment inlet by the second pump. Such a push effect can be also achieved by a generated nitrogen gas pressured into the second compartment. Using both pumping actions simultaneously is optional, but desired as it represents significant time savings as it allows unloading and loading the tank container at the same time. Naturally, also an empty container can be simply filled up with the incoming fluid while the solvent vapor supply inlet 1 removes present gases which would otherwise compress and prevent proper filling of the tank. At the loading/unloading location, the containerized pump is connected to a dedicated fluid riser(s) which provides a channel for ingoing or outgoing fluid(s). The whole system transfers petroleum fluids in very small batches, and as such each one can be chemically customized or diluted according to composition of the fluid and/or requirements of the final customer.

[0026] There are two designs of the intermodal container tank considered. Small version which is 20 feet long (TEU), 8 feet wide, 8.5 feet high, and the large version 40 feet long (FEU), 8 feet wide and 8.5 feet high. TEU has cargo weight capacity approx. 24 tones, FEU approx. 45 tones. FEU weight is non-standard for a similar container of such size, but it is still within limits for Canadian road transport, which is 63 tones for a truck GVW (Gross Vehicle Weight) (Alberta, 2018). In most US states the road GVW weight limit is 80000 Lbs. (Transportation, 2003), which, absent a special permit, technically prevents road movements of FEU container tanks within the US. Although FEU is nonstandard and overweight, it is still within the limits of mainstream heavy duty standard container yard lifting equipment. TEU intermodal tank has two compartments divided by a single diaphragm. FEU has three compartments, divided by two diaphragms. The two diaphragms form one middle 11 and two divided compartments 12 at each end. The volumes of the middle and the two side compartments together are equal when filled up, thanks to the plasticity of the dividing diaphragms. The side compartments 12 are designed for unrefined petroleum, where the diaphragms provide secondary containment measure in case of the tank wall breach (dividing the tank volume of 300 barrels into 2×150 barrels). Middle compartment 11 is designed for refined petroleum. All three compartments have their own excessive vacuum breaker valves and overpressure control valves together with a dedicated manhole. They are also equipped with pressure and tank level sensors.

[0027] The invention has now been described with reference to preferred embodiments. Substitution of parts and other modifications will now be apparent to persons of ordinary skill in the art. In particular, the present invention may be utilized to transport refined or unrefined liquid other than petroleum, such as tallow or other biofuel feedstock. Accordingly, the invention is not intended to be limited except as provided by the appended claims.