Carbon Dioxide Injection for pH Adjustment in Gasification Systems

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Solution Overview

Problem

Gasification systems face challenges in pH adjustment, particularly in managing strongly basic streams, where the use of strong mineral acids is common, and there is a need for efficient methods to control pH levels in downstream systems like grey water treatment, which often require multiple steps and external supplies of pH-adjusting agents.

Innovation Solution

Incorporating a carbon dioxide injection system within the gasification process to adjust pH levels, utilizing carbon dioxide produced internally through units like pressure swing adsorption or acid gas removal, which forms carbonic acid and bicarbonate to reduce pH effectively, thereby reducing reliance on external supplies and strong mineral acids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strong mineral acids are used to adjust pH in downstream systems, then pH control is achieved, but system complexity and safety risks increase

Engineering Contradiction:
ImprovepH control precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The gasification system produces its own carbon dioxide through the gasification process, which is then used for pH adjustment in downstream systems. This eliminates the need for external carbon dioxide supplies and reduces system complexity by using an internally generated resource to solve a downstream problem.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Carbon dioxide serves as an intermediary substance that transfers the pH adjustment function from direct acid addition to a more controlled gas dissolution process. The CO2 dissolves in water to form carbonic acid, providing gradual and controllable pH reduction without the hazards of handling strong mineral acids.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If multiple pH adjustment steps are implemented, then pH stability improves, but process complexity increases

Engineering Contradiction:
ImprovepH stabilityVSAvoidprocess complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system implements continuous pH adjustment by constantly injecting carbon dioxide into the water stream rather than using discrete batch additions. This continuous action maintains pH stability within the desired range while simplifying the control mechanism compared to multiple stepped adjustments.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system uses pH sensors to continuously monitor the pH level in downstream systems and provides feedback to the carbon dioxide injection system. This closed-loop control automatically adjusts the CO2 injection rate to maintain pH within the target range, achieving stability without complex manual intervention.

Inventive Principle:
Principle #23Feedback

3Reliability

If external carbon dioxide supplies are used, then pH adjustment capability is ensured, but system independence and cost increase

Engineering Contradiction:
ImprovepH adjustment capabilityVSAvoidexternal material supply
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The gasification system produces its own carbon dioxide through the gasification process, which is then used for pH adjustment in downstream systems. This eliminates the need for external carbon dioxide supplies and reduces system complexity by using an internally generated resource to solve a downstream problem.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of discarding the carbon dioxide produced during gasification, the system recovers and utilizes it for pH adjustment in downstream water treatment systems. This transforms a potential waste stream into a valuable resource, eliminating the need for external CO2 supplies.

Inventive Principle:
Principle #34Discarding and recovering

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 stabilizes pH levels, increases the efficiency of gasification systems, and allows for precise control of pH adjustment in single or multiple steps, reducing the need for strong mineral acids and external carbon dioxide supplies.

Implementation Method 1

carbon dioxide is capable of reducing the pH of strongly basic streams, even through carbon acid and bicarbonate are relatively weak acids

Methodology Applied
Scientific EffectCarbonic acid formation:

Implementation Method 2

carbonic acid forms a buffer solution with water, thereby stabilizing the pH of the water

Methodology Applied
Scientific EffectBuffer solution formation:

Data Source

PatentEP2885382B1Ph adjustment within gasification system
Publication Date: 2019.03.27 AIR PROD & CHEM INC
  • EP2885382B1 patent drawingFigure 1
  • EP2885382B1 patent drawingFigure 2
  • EP2885382B1 patent drawingFigure 3

AI summary

A gasification system includes a water source, a downstream system configured to receive a first stream having water from the water source, and a carbon a carbon dioxide injector configured to adjust a pH of the water using a second stream having carbon dioxide to form pH-adjusted water.