Backup Absorber for Sulfuric Acid Plants

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Solution Overview

Problem

Existing sulfuric acid plants face challenges in maintaining effective SO2 emission control, especially when the primary amine absorption process is interrupted or compromised, leading to potential atmospheric releases and high capital and operational costs associated with backup systems or running multiple plants at half capacity.

Innovation Solution

A discontinuously operating back-up absorber system that uses a lean solvent storage tank to maintain continuous operation for at least two hours, diverting feed or offgas to the back-up absorber and regenerating the solvent using waste heat, allowing for automatic start-up and reducing capital and operational costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an additional continuous amine absorption system is implemented as a back-up system, then SO2 removal capacity is improved, but capital cost and device complexity increase significantly

Engineering Contradiction:

ImproveSO2 removal capacityVSAvoidcapital cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The back-up system is segmented into a smaller absorber unit with reduced solvent circulation capacity, designed to handle only the specific load required during primary system failures rather than full continuous operation. This segmentation allows reduced capital cost while maintaining adequate SO2 removal capacity during emergencies.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The back-up absorber is designed with partial action capability - it operates at reduced capacity (handling only the portion of SO2 removal needed during failures) rather than requiring full continuous operation capacity. This partial sizing reduces equipment size, capital cost, and complexity while still providing reliable back-up protection.

Inventive Principle:

Principle #16Partial or excessive action

2Reliability

If two full-sized sulfuric acid plants are run in parallel, then SO2 removal reliability is improved, but operational cost and device complexity increase substantially

Engineering Contradiction:

ImproveSO2 removal reliabilityVSAvoidoperational cost

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of duplicating full-sized plants, the solution segments the back-up capability into a single smaller absorber unit that provides targeted protection during failures. This eliminates the need to operate two full plants in parallel, substantially reducing operational costs while maintaining SO2 removal reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The back-up absorber is designed as a temporary, lower-cost solution activated only during primary system failures. It operates discontinuously for limited periods (handling emergency loads) rather than continuously, reducing both capital and operational costs compared to maintaining two full-sized plants.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If a discontinuously operating back-up absorber is used, then capital cost is reduced, but SO2 removal capacity during start-up is limited

Engineering Contradiction:

Improvecapital costVSAvoidSO2 removal capacity during start-up

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The back-up absorber is sized to provide adequate SO2 removal capacity for the specific emergency scenario (primary system failure during continuous plant operation) rather than attempting to handle all possible operating conditions. This partial sizing reduces capital cost while providing sufficient protection during start-up and failure scenarios.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The back-up system parameters (solvent circulation rate, absorber size) are optimized for discontinuous emergency operation rather than continuous full-capacity operation. This parameter optimization allows reduced equipment size and lower capital cost while maintaining adequate SO2 removal capacity during the specific conditions when the back-up is activated.

Inventive Principle:

Principle #35Parameter changes

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

Enables continuous SO2 removal from sulfuric acid plants during primary absorber failures or shutdowns, reducing capital and operational costs while ensuring regulatory compliance and minimizing environmental impact.

Implementation Method 1

the feed gas or offgas is contacted with a lean solvent in the back-up absorber to form a rich solvent

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

regenerating the solvent using waste heat

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS9440181B2Back-up configurations and method for sulfuric acid plants

Publication Date: 2016.09.13 FLUOR TECH CORP

AI summary

A sulfuric acid production plant has a discontinuously operating back-up absorber to allow for sulfur emission control in situations where part of or even the entire sulfuric acid production plant is shut down, inoperable, or otherwise compromised. The back-up absorber receives lean solvent from a storage tank that is configured such that continuous operation of the back-up absorber is possible for several hours.