A two-stage high-temperature preheated steam gasifier

Abstract

A gasifier is disclosed combing two reactors using externally generated preheated high temperature steam injection into the first reactor, where the heating demand for gasification is supplied by the sensible energy from the steam. The gasifier can produce a medium and higher LCV syngas. The first reactor is a fixed bed gasification section where the coarse feedstock is gasified, and the second reactor is an entrained-bed gasification section where the liquid and fine feedstock is gasified. Solid coarse feedstock is devolatilized in the first fixed bed reactor of the gasifier by means of high-temperature steam, and subsequently, in the second reactor subjected to a higher temperature sufficient to crack and destroy tars and oils. Activated carbon may be formed as co-product. The gasifier may be used with various solid and liquid feedstocks. The gasifier is capable of gasifying such different feedstocks simultaneously.

Description

field of invention [0001] The present invention relates generally to two-stage high temperature steam gasifiers for the production of synthesis gas and optionally activated carbon from coarse carbonaceous feedstocks, and more particularly to the ability to simultaneously gasify coarse solid carbonaceous feedstocks and fine solid carbonaceous feedstocks. feedstock or liquid carbonaceous feedstock. The present invention also relates to a process for the gasification of crude carbonaceous feedstock to produce synthesis gas and optionally activated carbon using a two-stage gasifier having two reactors, wherein no oxygen is fed to the first-stage reactor, only Preheated steam is fed with a temperature of at least 700°C. Background of the invention [0002] Gasification is the conversion of solid feedstocks such as solid coal, petroleum coke, biomass and / or solid waste, liquid feedstocks such as black liquid oil or gaseous feedstocks using reactants such as air, steam and oxygen,...

AI Technical Summary

Problems solved by technology

This results in a decrease in the LCV of the generated fuel gas

Furthermore, the injection of secondary air makes it difficult to control the composition of the generated gas

[0022] The aforementioned US 6,960,234 also states that fixed bed gasification requires crude fuel typically 1 / 4"-2" in diameter, and that the limiting technical features of fixed bed gasification include: tar and oil being carried over by syngas; difficulty in using coal / fuel fines , because they block the void space between crude fuels in fixed beds; and are difficult to use with liquid hydrocarbon feeds

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