Oil fire and boil over attenuation using buoyant glass materials

Abstract

A method is described for using cellular glass blocks, cellular glass nodules, hollow glass spheres, or other buoyant glass materials to attenuate oil fire, limit thermal radiation from an oil fire, and reduce the risk of boil-over phenomenon. Cellular glass blocks, cellular glass nodules, hollow glass spheres, or other buoyant glass products may be deployed passively, prior to an ignition event, or actively, as a response to an ignition event to provide control. Cellular glass or other buoyant glass materials may be in any physical shape such as block, sheet, aggregate, or nodule.

Claims

1. A method of extinguishing an oil fire in an oil-containing vessel containing oil having a surface, the method comprising: placing cellular glass blocks on top of a floating roof of the oil-containing vessel prior to an ignition event causing the oil fire; retaining the cellular glass blocks on top of the floating roof of the oil-containing vessel until such time as the oil fire collapses the roof of the oil-containing vessel; coating the cellular glass blocks with high expansion foam; sinking the floating roof of the oil-containing vessel in the oil; and floating the coated cellular glass blocks on the surface of the oil contained in the oil-containing vessel in order to extinguish the oil fire.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) For the present invention to be clearly understood and readily practiced, the present invention will be described in conjunction with the following figures, wherein like reference characters designate the same or similar elements, which figures are incorporated into and constitute a part of the specification, wherein;

(2) FIG. 1 illustrates an example of cellular glass in block form.

(3) FIG. 2 illustrates an example of cellular glass in sheet form.

(4) FIG. 3 illustrates an example of cellular glass in aggregate form.

(5) FIG. 4 illustrates an example of cellular glass in nodule form.

(6) FIG. 5 illustrates an example of cellular glass in hollow sphere form.

(7) FIG. 6 illustrates an example of an external floating roof oil tank with a passive system of cellular glass block deployed in two layers.

(8) FIG. 7 illustrates a cross-section detail of an external floating roof oil tank with a passive system of cellular glass block deployed in two layers.

(9) FIG. 8 illustrates a partial cross-section detail of a passive system of a cellular glass block layer beneath a roof.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(10) It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the invention. The detailed description will be provided hereinbelow with reference to the attached drawings.

(11) Cellular glass is a material composed primarily of glass that contains a significant number of completed closed bubbles in the material to form a lower density material than a solid glass product. Cellular glass may generally range in density from three pounds per cubic foot up to the density of the oil product in which it will ultimately need to float (which will vary). The greater the difference between the density of cellular glass and that of the oil, the more buoyant the cellular glass system will be, and the greater the protection the system will provide.

(12) Cellular glass will be closed celled, so that oil absorption will not result in premature system failure due to the cellular glass sinking in oil. Other glass products such as hollow glass spheres may also be utilized due to the buoyant nature of the material.

(13) Cellular glass may be in block (FIG. 1), sheet (FIG. 2), aggregate (FIG. 3) or nodule (FIG. 4) form. Individual blocks preferably are no more than a few feet in length or width and no more than twelve inches thick. Multiple blocks may be constructed into large sheets using adhesive or mechanical fasteners, or specifically fabricated to cap the roof area of the storage vessels. Aggregate cellular glass is typically smaller than a few inches in diameter and may or may not have uniform geometry. A nodule is characterized as a small uniform diameter spherical or cubic cellular glass shape and typically is less than a few inches in diameter. Unlike multicellular glasses, hollow glass spheres (FIG. 5) are a singular glass cells, and are typically smaller than a quarter of an inch in diameter.

(14) Cellular glass may have a surface coating used to improve weatherability and fire control. These coatings can include, but are not limited to, UV resistant and intumescent materials.

(15) Other buoyant glass materials may also be utilized in the application for limiting risks associated with oil fires. In one embodiment of this invention, the glass material can be hermetically sealed buoyant glass spheres. The hollow glass spheres will typically be less than half an inch in diameter. These products may be either used in a passive deployment basis or placed onto a fire surface during response. One example of this invention would include adding hollow glass spheres to a firefighting foam.

(16) With reference to FIGS. 6-8, an embodiment of the present invention known as passive development is illustrated. With passive deployment, a buoyant cellular glass material 10 is placed on the roof 12 of an oil storage vessel 14 prior to an ignition event, where it will stay until such time as an oil fire collapses the roof 12 of the vessel 14. The roof 12 of the vessel 14 will subsequently sink in the burning oil 16, and the cellular glass 10 will float on the surface of the oil 16, thus attenuating the oil fire, limiting thermal radiation from the oil fire, and reducing the risk of boil over phenomenon resulting from vaporization of a liquid phase in the fuel.

(17) During testing of the passive deployment of cellular glass on crude oil, temperatures only reached 140° C. in the uppermost layer of the oil after 100 minutes. No hot zone development was observed with the blocks in situ. While there is some heat conduction, penetration of the heat was low and boilover did not occur.

(18) Examples of how cellular glass may be utilized in a passive deployment are as follows: Cellular glass is deployed on the roof of oil storage vessel prior to ignition event in block, sheet, aggregate or nodule form. Cellular glass is deployed in blocks or sheets covering the surface of the roof area on an oil storage vessel. Cellular glass block or sheet may be deployed in a single layer or multiple layers up to a maximum weight the roof of the oil storage vessel is able to support. Cellular glass may be deployed as aggregate loosely strewn across the roof area of the oil storage vessel in depths up to a maximum weight the roof of the oil storage vessel is able to support. Cellular glass may be deployed as aggregate in bags aimed to contain the cellular glass until it is released by oil fire.

(19) Cellular glass may be deployed under the roof, serving as the fire-resistant flotation component of the roof itself (FIG. 8). Glass spheres may be deployed loosely strewn across the roof area of the oil storage vessel in depths up to a maximum weight the roof of the oil storage vessel is able to support. Glass spheres may be deployed in bags aimed to contain the spheres until it is released by oil fire.

(20) As opposed to passive deployment, active deployment refers to the release of cellular glass, hollow glass spheres or other buoyant glass in response to ignition and fire in order to attenuate oil fires, limit thermal radiation from oil fires, and reduce the risk of boil over phenomenon resulting from vaporization of a liquid phase in the fuel. The cellular glass aggregate or hollow glass spheres may be deployed, for example, via pneumatic or mechanical systems. In this methodology, the buoyant glass product may be mixed with a firefighting foam or spread onto the surface of the oil using another methodology, such as a pneumatic gravel truck or gravity fed via a storage bin.

(21) Although the invention has been described in terms of particular embodiments in an application, one of ordinary skill in the art, in light of the teachings herein, can generate additional embodiments and modifications without departing from the spirit of, or exceeding the scope of, the claimed invention. Accordingly, it is understood that the drawings and the descriptions herein are proffered by way of example only to facilitate comprehension of the invention and should not be construed to limit the scope thereof.