Method of Operation of Process to Produce Syngas from Carbonaceous Material

Abstract

A process is provided for producing syngas that is effective for use in downstream processes. The process for producing syngas includes operating a gasification apparatus in a start-up mode until the gasification apparatus and equipment downstream of the gasification apparatus are adequately warmed up to a first target temperature. Upon reaching a first target temperature, the process is then operated in a production mode to produce a second syngas with a higher CO / CO2 molar ratio. Operation in a start-up mode until reaching a first target temperature, provides a process that is effective for reducing fouling in downstream equipment and for providing a second syngas can be more effectively cooled and cleaned.

Description

[0001]This application claims the benefit of U.S. Provisional Application Nos. 61 / 516,646, 61 / 516,704 and 61 / 516,667 all filed Apr. 6, 2011, all of which are incorporated in their entirety herein by reference.[0002]A process is provided for gasification of carbonaceous materials to produce producer gas or synthesis gas or syngas comprising carbon monoxide and hydrogen. More specifically, the process is effective for producing cooled syngas for downstream use. The process utilizes gasification of carbonaceous materials to produce a syngas followed by cooling of said syngas to produce cooled syngas and optionally cleaning said cooled syngas to produce a clean syngas for several downstream processes.BACKGROUND[0003]Gasification of carbonaceous materials to produce producer gas or synthesis gas or syngas comprising carbon monoxide and hydrogen is well known in the art. Typically, such a gasification process involves a partial oxidation or starved-air oxidation of carbonaceous material i...

AI Technical Summary

Benefits of technology

[0009]A process is provided for producing syngas that is effective for use in downstream processes. The process for producing syngas includes operating a gasification apparatus in a start-up mode until the gasification apparatus and equipment downstream of the gasification apparatus are adequately warmed up to a first target temperature. Upon reaching a first target temperature, the process is then operated in a production mode to produce a second syngas with a higher CO / CO2 molar ratio. Operation in a start-up mode until reaching a first target temperature provides a process that is effective for reducing fouling in downstream equipment and for providing a second syngas can be more effectively cooled and cleaned. The second syngas with a higher CO / CO2 molar ratio that is cooled and cleaned is especially useful for fermentation processes.

[0012]In another aspect, a process is provided to produce syngas that includes adding carbonaceous material and molecular oxygen to a gasification apparatus to produce a first syngas with CO / CO2 molar ratio less than 0.5. The temperature of the first syngas is measured downstream of the gasification apparatus. Temperature may be measured prior to entry into a syngas cooler or downstream of a syngas cooler. Once the syngas reaches a first temperature prior to entry into a syngas cooler, addition of molecular oxygen is reduced per unit mass of carbonaceous material in the gasification apparatus to produce a second syngas with CO / CO2 molar ratio greater than that of said first syngas. The first target temperature is about 700° C. to about 1000° C. Reduction of addition of molecular oxygen per unit mass of carbonaceous material may be accomplished by increasing rate of addition of carbonaceous material. Alternatively, reduction of addition of molecular oxygen per unit mass of carbonaceous material may be accomplished by decreasing rate of addition of molecular oxygen.

Problems solved by technology

However when carbon monoxide is cooled, carbon monoxide may oxidize into carbon dioxide, and produce carbon (graphite) that precipitates as soot:

This reaction is generally known as Boudouard reaction and is believed to take place at or below about 760° C. Fouling of heat transfer surface caused by deposit of carbon can cause disruption in operation of a syngas cooler.

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