Two-Stage Gasifier Quench Section for Low Methane Syngas

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Solution Overview

Problem

Gasification processes produce synthesis gas with high methane content, which is detrimental to chemical production processes, requiring expensive pre-treatment to remove methane, thereby necessitating a method to produce low-methane synthesis gas without such treatment.

Innovation Solution

A two-stage gasification reactor process that includes a quench section to extract a methane-depleted gas stream from the synthesis gas produced, reducing methane content to less than 0.6% volume, allowing direct utilization as a feedstock for chemical production without additional processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a two-stage gasification reactor is used to produce synthesis gas, then energy efficiency is improved through heat utilization, but methane content in the synthesis gas increases to unacceptable levels for chemical production

Engineering Contradiction:
Improveenergy efficiencyVSAvoidmethane content
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The gasification process is divided into two distinct stages: a first stage for partial oxidation and heat generation, and a second stage for pyrolysis and synthesis gas production. This segmentation allows the hot synthesis gas from stage one to provide thermal energy to stage two, improving overall energy efficiency while enabling separate control of methane generation and removal

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Methane is extracted from the synthesis gas stream by withdrawing a portion of the hot synthesis gas from the first stage reactor and routing it to a separate methane conversion reactor. This extraction removes the harmful methane component before the gas is combined with the second stage output, solving the methane content problem while preserving the energy-efficient two-stage configuration

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If synthesis gas with high methane content is produced, then production volume is maintained, but additional expensive processing equipment is required to remove methane

Engineering Contradiction:
Improvesynthesis gas production volumeVSAvoidprocessing equipment
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention merges the methane removal function with the existing two-stage gasification system by integrating a methane conversion reactor that receives a portion of the first stage output. The converted gas is then combined with the second stage synthesis gas, achieving methane removal without requiring separate expensive treatment equipment while maintaining high production volume

Inventive Principle:
Principle #5Merging (Combining)

3Object-generated harmful factors

If methane removal processes are implemented, then methane content is reduced to acceptable levels, but processing costs increase significantly

Engineering Contradiction:
Improvemethane contentVSAvoidprocessing cost
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The invention converts the harmful methane component into a beneficial thermal resource by routing a portion of the hot synthesis gas through a methane conversion reactor where methane is converted to additional synthesis gas. This conversion both removes the harmful methane and recovers energy, reducing processing costs while achieving the required methane content reduction

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The process effectively reduces methane content in synthesis gas to suitable levels for chemical production, eliminating the need for expensive methane removal treatments and enhancing the efficiency of chemical synthesis processes.

Implementation Method 1

partially oxidizing a first carbonaceous feedstock in the at least one reaction zone to produce a product gas comprising H2, CO, and methane

Methodology Applied
Scientific EffectPartial oxidation: Oxidation

Implementation Method 2

a quench section having a second outlet, wherein the quench section cools molten ash and removes the molten ash via the second outlet

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP2523897B1Producing low methane syngas from a two-stage gasifier
Publication Date: 2021.02.24 LUMMUS TECHNOLOGY INC
  • EP2523897B1 patent drawingFigure 1

AI summary

The present disclosure relates generally to a method for obtaining synthesis gas from a gasifier that has a low methane content. The synthesis gas is obtained as an extraction gas from the quench section of the gasifier, and can be utilized as feedstock for a variety of chemical production processes without the need for expensive pre-treatment to remove methane.