Bulk fueled gasifiers

Abstract

A gasifier includes a gasifier shell, means for introducing fuel into the shell, and means for introducing oxygenate into the shell. The gasifier also includes means for discharging gas from the shell, which can be located below the means for introducing oxygenate. The gasifier can also include means for re-circulating gas prior to gas being discharged from the shell.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 846,790, filed Sep. 22, 2008, U.S. Provisional Application No. 60 / 850,944, filed Oct. 11, 2008, and U.S. Provisional Application No. 60 / 875,483, filed Dec. 18, 2008.BACKGROUND OF THE INVENTION[0002]This invention relates generally to gasifiers. Two types of gasifiers are bulk fuel fed and entrained flow fed. Entrained flow fed gasifiers require more fuel processing such as pulverizers and slurring of coal, for example. Entrained flow also requires other extra equipment such as blowers and bag house. This extra fuel preparation increases the cost and complexity of the gasifier and also lowers reliability. Entrained flow gasifiers also tend to be very large and cumbersome, with present reliability so poor that two gasifiers are frequently supplied to do the job of one.[0003]Bulk fuel fed gasifiers are generally simpler than entrained flow gasifiers, but they typical...

AI Technical Summary

Benefits of technology

[0010]FIG. 3 is a side elevation view of a non-

Problems solved by technology

This extra fuel preparation increases the cost and complexity of the gasifier and also lowers reliability.

Entrained flow gasifiers also tend to be very large and cumbersome, with present reliability so poor that two gasifiers are frequently supplied to do the job of one.

Bulk fuel fed gasifiers are generally simpler than entrained flow gasifiers, but they typically employ counter-current designs that tend to create undesirable tars.

Tars that are very undesirable to further process gas either into syncrude or for power plants because cleaning up the tars requires extra processes and coats the inside of gas piping, all of which increases gasification costs and decreases reliability.

However, down draft gasifiers generally have been limited to low fuel moisture levels because there was no method to dry the fuel within the gasifier.

But the upper gas exit temperatures are limited in updraft gasifiers by the blast flow rate and how much heat energy can be pulled upwards.

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