Charcoal/ash removal system for a downdraft gasifier and associated methods

Abstract

A method and apparatus is provided for use in a fixed-bed gasification system for the disengagement of gas and the removal of ash and charcoal. In one example, the invention includes an auger system, a water seal system, and a gas disengagement system. The gas disengagement mechanism prevents plugging and blinding of the gas offtake system and simultaneously limits particulate entrainment in the gas produced by the gasifier.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority under 35 U.S.C. § 119 to co-pending, commonly owned U.S. provisional patent application Ser. No. 60 / 947,545, attorney docket number EER.P0036P, filed on Jul. 2, 2007 entitled “CHARCOAL / ASH REMOVAL SYSTEM FOR A DOWNDRAFT GASIFIER”, which is incorporated by reference herein.FIELD OF THE INVENTION[0002]This invention relates to fixed-bed gasification systems. In particular, this invention is drawn to gasification systems that remove charcoal and ash from a fixed bed of solids, and that are simple, robust, and cost-effective.BACKGROUND OF THE INVENTION[0003]Energy conversion devices, such as gasifiers, designed to convert solid fuel to heat and power, are significant to the world's energy infrastructure. A gasifier is operated by limiting the air required for complete combustion in order to primarily produce a low-Btu gas comprised of hydrogen, carbon monoxide, methane, carbon dioxide, and nitrogen. Gasifiers ...

AI Technical Summary

Benefits of technology

[0011]Another embodiment of the invention provides a method of disengaging gas and removing charcoal and ash in a fixed-bed gasifier including providing a conduit disposed generally below the gasifier, and extending away from the gasifier, conveying charcoal and ash away from the gasifier through the conduit, forming a vertical gas discharge port in the conduit, allowing gases produced by the gasifier to exit the gasifier, and sealing an end of the conduit with a water seal for preventing gas from passing through the water seal.

Problems solved by technology

One problem with many systems, is that the techniques do not provide all of the desirable features of a fixed-bed gasification process.

No system currently addresses all of these desirable features.

Some systems provide examples of wet removal processes that are limited to removal of the solids but do not address gas offtake systems.

However, this process is not a simple extraction and disposal technique, but rather a complicated high-pressure reinjection technique for a large-scale coal gasifier.

The following examples show various systems for charcoal removal from gasifiers that are subject to problems with particulate entrainment, exhaust manifold fouling, dust, spontaneous ignition of spent charcoal, and process sealing issues, although none of the examples provide for a means of wet removal.

However, this configuration prevents gas disengagement and does not provide a water tight seal.

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