Feed System

Abstract

Transport system for the introduction of biomass into a gasifier comprising: a plug screw that forces the biomass into the gasifier, wherein the plug screw is formed such that the biomass is compressed in order on the one hand for it to be conveyed against a pressure in the gasifier and, on the other hand, to leave the gas and bed material in the gasifier, having a gate valve adjacent to the plug screw and which closes when the plug screw stops so that heat, vapour and gas cannot escape.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of PCT / EP2007 / 058034 filed Aug. 2, 2007, which claims priority of DE 10 2006 039 622.7 filed Aug. 24, 2006, both of which are incorporated by reference.FIELD OF THE INVENTION[0002]The invention concerns a system for feeding biogenic feedstock into a gasifier, more particularly into a pulse gasifier in accordance with applications DE 10 2006 022 265.2, DE 10 2006 017 355.4, DE 10 2006 017 353.8.BACKGROUND[0003]The development of thermal gasification processes has produced essentially three different types of gasifier, the entrained flow gasifier, the fixed bed gasifier and the fluidized bed gasifier.[0004]Originally, the fixed bed gasifier and the fluidized bed gasifier were developed for the commercial gasification of biomasses.[0005]The Carbo-V method will be illustrated here by way of an example for the many different technical approaches to fixed bed gasification.[0006]Literature for fluidized bed gas...

AI Technical Summary

Benefits of technology

[0023]An embodiment of the invention provides a transport system which delivers the biomass to the reactor efficiently taking into consideration the particular characteristics of the reactor.

[0031]When the gasifier is operating the material is fed into a dense, fluidized bed. Measures are taken to prevent the backflow of bed material into the plug screw when the feed screw is at a standstill, particularly in the start up and shut down processes. To this end, the system is equipped with a gate valve that operates through the material being conveyed and shuts off the flow in a suitable manner. This equipment also permits the plug screw(s) to be drained through a drainage arrangement as a precaution against the sort of backfires that cannot be excluded in the case of brief shutdowns of the otherwise hot gasifier.

Problems solved by technology

These types of gasifier are completely unsuited to the gasification of biomass (which occurs regionally and has a significant influence on the costs in terms of logistics and processing) because of the great technical effort and high economic costs demanded by the high pressure level (up to 40 bar).

The disadvantages are the high acquisition costs for the process engineering and excessive costs for process control.

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