Two-Stage Gasifier Feedstock Flexibility and Oxygen Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional gasification processes face inefficiencies in converting carbonaceous materials into synthesis gas, particularly in maximizing conversion efficiency and minimizing oxygen usage, especially in two-stage entrained gasification systems.

Innovation Solution

A two-stage gasification process that introduces a liquid hydrocarbon feedstock and a dry or slurried feedstock into a reactor through specific nozzles, with the liquid hydrocarbon feedstock supplementing the primary feedstock in the lower section and a second slurried feedstock in the upper section, leveraging heat from hot synthesis gas to support pyrolysis and gasification reactions, and recycling char back to the lower section to minimize oxygen requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a two-stage gasifier is used to convert carbonaceous materials into synthesis gas, then conversion efficiency is improved, but oxygen consumption increases

Engineering Contradiction:

Improveconversion efficiencyVSAvoidoxygen consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The gasifier is divided into two distinct stages: a first stage for partial combustion of feedstock to generate heat and synthesis gas, and a second stage for gasification of char and unconverted carbon using heat from the first stage. This segmentation allows efficient conversion while managing oxygen consumption by limiting oxygen input to only the first stage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Char and unconverted carbon exiting the second stage are separated and recycled back to the first stage in dry form. This recovery and reuse of unconverted material maximizes conversion efficiency while minimizing the amount of fresh oxygen required in the first stage, as the recycled carbon is gasified using heat from ongoing combustion rather than requiring additional oxygen.

Inventive Principle:

Principle #34Discarding and recovering

2Use of energy by moving object

If slurry feed rate is maximized to the lower temperature second stage, then heat utilization is improved, but water evaporation requirements increase

Engineering Contradiction:

Improveheat utilizationVSAvoidwater evaporation requirements

Core Design Contradiction:

Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The system uses the heat generated in the first stage gasifier to evaporate water from the slurry fed to the second stage. The hot synthesis gas from the first stage serves its own purpose of providing thermal energy for water evaporation in the second stage, creating a self-sufficient heat integration system that maximizes heat utilization without external energy input.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances feedstock flexibility, increases conversion efficiency, reduces oxygen consumption, and allows for continuous operation by optimizing temperature profiles and flow conditions within the reactor, thereby improving the overall performance and capital efficiency of the gasification system.

Implementation Method 1

partially combusting the feedstocks in the reactor lower section with a gas stream comprising an oxygen-containing gas or steam to evolve heat and form products comprising hot synthesis gas

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

introducing a second slurried feedstock into said reactor upper section, whereby heat from said hot synthesis gas supports reaction of the second slurried feedstock by pyrolysis and gasification reactions

Methodology Applied

Scientific EffectHeat transfer: Convection

Implementation Method 3

heat from said hot synthesis gas supports reaction of the second slurried feedstock by pyrolysis and gasification reactions

Methodology Applied

Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentUS11639477B2Two-stage gasifier and gasification process with feedstock flexibility

Publication Date: 2023.05.02 LUMMUS TECHNOLOGY INC

AI summary

A gasification process may include (a) introducing a liquid hydrocarbon feedstock and at least one of a dry feedstock or a first slurried feedstock into a reactor lower section, wherein the at least one dry feedstock or first slurried feedstock is introduced through two primary feed nozzles while the liquid hydrocarbon feedstock is introduced through at least two secondary feed nozzles; (b) partially combusting the feedstocks in the reactor lower section with a gas stream comprising an oxygen-containing gas or steam to evolve heat and form products comprising hot synthesis gas; (c) passing said hot synthesis gas from step (b) upward into a reactor upper section; (d) and introducing a second slurried feedstock into said reactor upper section, whereby heat from said hot synthesis gas supports reaction of the second slurried feedstock by pyrolysis and gasification reactions.