U.S. Patent 8,011,911 for “Method and system for pelletizing sulfur.”

Texas Business reports:  A Tyler resident has developed a method of processing sulphur.

Jean-Marie Koten of Tyler received U.S. Patent 8,011,911 for “Method and system for pelletizing sulfur.”

Koten filed for the patent on December 22, 2009.

The patent assignee is Brimcock International Inc. of Kilgore.

Koten’s invention relates to the field of converting molten sulfur (or sulphur) into solid pellets (or prills). 

Sulfur is used in numerous products, including fertilizers, gunpowder, insecticides, fungicides, paper, and textiles. It may be extracted directly from the earth, or it may be removed from other natural substances, such as coal, natural gas, or crude oil.

Liquid or molten sulfur produced as a by-product from petro-chemical refineries often contains particulate impurities known as "Carsul," which is a carbon sulfur polymer. Sulfur is usually produced, transported, and utilized within the United States in molten liquid form. It is inconvenient and expensive to store and transport sulfur in a molten form. In addition, before sulfur can be exported, generally, it has to be converted to solid form. 

For maximum commercial value, sulfur prills should be generally spherical in shape, uniform in size and density, and have low moisture content. Very small or fine pieces of sulfur, commonly known as "fines," are undesirable and create an enormous maintenance problem and potential fire and safety hazards and health problems for manufacturing personnel. High moisture content is undesirable because, among other things, the customer typically pays by weight, and less sulfur is received. Further, the increased weight increases the cost of shipping, and water and sulfur may create dangerous sulfuric acid. Sulfur prills typically should have a moisture content of 1.8% to 2.2% to command maximum commercial value and be acceptable for export. Moreover, the prills typically should meet the size and uniformity criteria set forth below in Table 1. 

A need exists for a method and system to convert liquid or molten sulfur to solid prills that produces prills meeting the size, uniformity, and moisture content criteria generally described above for maximum commercial value. The method and system would use an economical novel wet process of quenching the sulfur through a liquid medium, such as water. 

Koten’s method and system is disclosed for converting liquid sulfur into solid pellets or prills that are generally spherical in shape, without sharp edges, uniform in size and density, and have relatively low moisture content.

A two-stage nested strainer removes impurities from the molten sulfur that may otherwise contribute to maintenance delays. A heated drip tray creates uniform droplets of liquid sulfur. A heating system for the drip tray is incorporated onto the underside of the tray so as to allow efficient and uniform heating while minimizing any impact on operations should a leak occur. The droplets are passed through a forming tank that contains a liquid medium, such as water. In the exemplary embodiment, the bottom portion of the forming tank funnels the prills and water through a relatively smaller opening. Relatively warm water may be injected near the bottom of the tank. A lesser amount of relatively cool water is injected through novel injection conduits near the top surface of the water.

The injection conduits create a cool media zone in the top area of the forming tank where prills are initially formed. Solid prills accumulate in the bottom section of the forming tank. A sensing device detects when a sufficient number of prills have been accumulated in the forming tank, and activates a discharge gate valve to release the prills while maintaining a level of water in the forming tank to adequately continue the process. The prills exit the forming tank and traverse down a static curved screen to a vibrating screen. A multi-stage filtration system removes the fines and allows the filtered water to be re-circulated and cooled in a closed system. The prills are then transported to a medium for storage or transportation.