Method for processing sugar cane filter cake mud and extracting component products

This application is a National Stage of International Application No. PCT/US2006/01904 filed Jan. 20, 2006 (which was published in English), which claims priority to U.S. application Ser. No. 11/040,315 filed Jan. 21, 2005, each of which is hereby incorporated by reference in their entirety.

This application presents a process for the treatment of sugar cane filter cake mud that separates and extracts its components into usable products. It allows for the efficient elimination of a voluminous amount of waste material of the sugar industry and can be undertaken with relatively low energy consumption and reduced capital and operating investments as compared to existing technologies that employ organic solvents to produce only a crude wax.

For many years, efforts have been made to find practical uses for the byproducts of processed sugar cane. Chief among these is sugar cane filter cake mud. The mud is an abundant material, representing between 3-4% of the total crushed sugar cane. It is also an attractive material for exploitation as it possesses a wide and diverse range of materials and elements (more than 50 have been identified). However this complexity also complicates effective treatment of the mud. Indeed untreated mud ferments within days, and the decay of its components commences at that time.

The sugar industry currently treats the vast bulk of this mud as a waste product thereby incurring handling costs that vary according to the prevailing government environmental regulations. Typically, a portion of the mud is used as a fertilizer within a few miles of the facility that generated the mud. Such use is limited by the costs of transporting the mud and the capacity of soils to accept it. The balance of the mud is usually contained in some sort of closed system such as an oxidation lagoon where it is mixed with water, allowed to decompose and then transported for disposal. These closed systems divert lands from other uses and incur significant maintenance costs.

Policosanol, which is a second generation mud derivate, is one of the useful by-products of sugar cane processing, and is, itself, a valuable substance having a number of beneficial uses. The principal impediment to the widespread use of policosanol, however, is the extremely high cost of producing it. However, by using this refined wax, it is possible to considerably reduce the cost of producing policosanol. Accordingly, the refined wax provided by embodiments of the process disclosed herein can be an attractive starting material for the production of policosanol and phytosterols by standard processes.

This process of this invention eliminates the need for current treatment and disposal practices. In its broadest application the invention can by illustrated by way of a facility that warehouses and processes all the available mud generated in a sugar cane cultivation zone. Alternatively the process can be established on a smaller scale, including processing the mud at the site of a sugar mill or other location. The process of this invention effectively closes the industrial cycle of sugar cane production by taking the primary sugar cane by-product for which no practical use has been established and treating it in such a way that substantially all component parts are inexpensively separated and may then be applied to other uses. These component parts are thereby made available for immediate as well as secondary exploitations, and no wastes need remain at the conclusion of the process. Additionally the process can be readily modified to extract other sub-components as uses for these are identified.

According to the various embodiments of this invention, sugar cane wax in the form of an aqueous emulsion, substantially free of fiber, resin and oil can be obtained by contacting sugar cane mud with a liquid extractant to form a mixture of the extractant, sugar cane wax, fiber, resin and an oil; emulsifying the sugar cane wax in the extractant to provide a mixture containing solids suspended in the liquid phase or emulsion; and clarifying the liquid phase by extracting the solids. The solids contained in the emulsion prior to extraction include the fiber, the resin and the oil; absorbed on the resin. A preferred extractant is water. Additional processing steps, as described below, provide sugar cane wax in a substantially pure dry state.

A preferred process delivers the mud sequentially to a series of extractors in each of which the mud is hydrated, heated, and agitated. The resulting mixture is transported from one extractor to another via a series of pipes, each having an internal rotary worm-screw to move the mixture to the next extractor. The screw feeder pipes also have perforations in their lower portions to allow gravity to separate and remove liquids that are released from the mixture during transport. Each of the liquids is collected, retained, and re-used during one of the treatment processes. At one stage, the separation of the mixture is induced by placing it in a centrifuge, which causes the separation of resins and waxes. Through the process of this invention, each major component of the mud can be extracted and thereafter used for other purposes.

It is an object of this invention to provide a process whereby sugar cane filter cake mud can be separated into usable components. It is a further object of this invention to provide a method whereby usable components of sugar cane filter cake mud can be extracted. It is yet a further object of the invention to provide a process for disposing of otherwise unusable byproducts of sugar cane processing, and in particular for disposing of sugar cane filter cake mud. These and other objects of the invention will become apparent through the following description of the invention.