The Application
41.The description of the Application begins with a general statement about what the invention is intended to be: “[0001] This invention relates to a biodiesel composition and process for producing biodiesel and related products. The invention also relates to fuels and fuel blends comprising biodiesel. In particular, the invention relates to a biodiesel composition prepared from a mixture comprising fats, oils and greases from sewer waste.” 42.Accordingly, the reader is informed from the start that the focus of the invention is a biodiesel composition. The description continues, setting out the background state of the art. It introduces characteristics of biodiesels including their fatty acid methyl ester (‘FAME’) content and their ‘cetane number’. The cetane number of a diesel fuel is a measure of how quickly it ignites. The higher the cetane number, the faster the ignition and the better the fuel, especially for high speed engines. The description informs the reader that the starting material (‘the feedstock’) used to make the fuel is important to the qualities of the fuel obtained: “[0009] In general, the starting material used has a large impact on the quality of the diesel obtained, and FAME and the cetane number. In particular, low quality starting materials are normally associated with fuels having low FAME and low cetane number. A number of other measurements determine overall diesel fuel quality including: density, lubricity, cold-flow properties (cold filter plugging point), mono-glyceride content, and sulphur content. These measurements are also typically affected by the quality of the starting material used.” 43.Of the further measurements of quality there mentioned, the cold filter plugging point came to have significance at the trial. It is a measure of the temperature at which the biodiesel will cease to flow freely. 44.The background section of the description ends by suggesting that the invention provides a practicable means of using sewer grease as the starting point for making biodiesel fuel: “[0013] Therefore, due to the impure and unpredictable nature of sewer grease, it has not been practicable to use sewer grease as a source of fats, oils and greases for producing fuels such as biodiesel. [0014] It is an object of the present invention to overcome or mitigate at least some of the problems of the prior art.” 45.There follows a section headed ‘Summary of the Invention’ which largely sets out the claims. The claims are all product claims being biodiesel compositions containing particular esters by weight, plus two claims at the end, one a fuel and the other a fuel blend. Again, the reader is given to understand that the invention or inventions are products, specifically biodiesel compositions. 46.After a description of the drawings, there is a long section headed ‘Detailed Description’ which continues up to the claims. BDI relied on the first three paragraphs: “[0031] Obtaining biodiesel from sewer grease involves first purifying the sewer waste. This involves filtering the sewer waste to minimise the aqueous phase, remove any solid particulates, and maximise the organic phase (i.e., the sewer grease fraction). This is described in more detail below under the Purification heading. [0032] After purification, it may be necessary to reduce the free fatty acid (FFA) content of the mixture. Typically this is done using high pressure esterification as is known in the art. For example, high pressure esterification may be carried out at approximately 190oC to 260oC and approximately 65 bar (6.5 MPa) to 100 bar (10 MPa) in the presence of methanol. [0033] After purification, and optional high pressure esterification, the biodiesel production process may commence. The biodiesel production process is broken down into two areas, namely esterification (referred to as preesterification) and trans-esterification. The pre-esterification and transesterification processes as further described below under the appropriate headings, and are illustrated in the flow diagram of Figure 3.” 47.The process stages of purification, pre-esterification and trans-esterification are described in detail. Examples are given with tables setting out their properties. The description then identifies advantages of the biodiesels having the compositions claimed. Paragraphs [0089] to [0091] state the biodiesel compositions of the invention derived from sewer grease provide a relatively high cetane number, a high cold filter plugging point and low density. 48.Paragraph [0094] says that a further advantage of the composition of the invention is that it provides a biodiesel fuel made from a material that would otherwise be waste material, i.e. sewer grease. In similar vein, paragraph [0095] states that the process described enables the use of feedstocks which to date had been impracticable for use in making biodiesel fuels. The description concludes with paragraph [0096] which tells the reader that the process described provides a reduction in throughput time for making biodiesel from a feedstock.
The claims
49.I need set out only claim 1: “1. A biodiesel composition comprising a mixture of esters, wherein the ester mixture comprises from 7% by weight to 10.5% by weight methyl octadecenoate, and from 39% by weight to 41% by weight methyl cis-9octadecanoate.”