Sulfuric Acid Pre-Drying Absorber for Humid Environments

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Solution Overview

Problem

Sulfuric acid production systems face inefficiencies in humid environments, leading to reduced steam production and energy efficiency, particularly due to excessive water in ambient air affecting the water balance and sulfuric acid concentration, which complicates heat recovery and increases energy requirements.

Innovation Solution

Incorporating a pre-drying absorber that uses weak sulfuric acid to remove excess water from ambient air, followed by a two-stage sulfur trioxide absorption subsystem with a heat exchanger for enhanced steam production and energy recovery, allowing for improved control and reduced energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If complex heat exchanger arrangements are used to improve energy efficiency, then energy recovery is improved, but device complexity increases

Engineering Contradiction:

Improveenergy efficiencyVSAvoiddevice complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The absorption system is divided into multiple independent absorption stages (first absorption stage, second absorption stage, third absorption stage) with separate heat exchangers for each stage. This segmentation allows each stage to be optimized independently for heat recovery while maintaining overall system functionality, resolving the contradiction between energy efficiency and device complexity.

Inventive Principle:

Principle #1Segmentation

2Productivity

If multiple contact and absorption stages are used to maximize conversion, then conversion efficiency is improved, but device complexity increases

Engineering Contradiction:

Improveconversion efficiencyVSAvoiddevice complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The conversion and absorption process is segmented into three distinct absorption stages, each with its own heat exchanger and acid circulation system. This segmentation enables high conversion efficiency through multiple stages while allowing each stage to be independently controlled and optimized, thereby managing overall device complexity.

Inventive Principle:

Principle #1Segmentation

3Loss of energy

If heat recovery system is integrated into absorption tower, then energy efficiency is improved, but reliability decreases

Engineering Contradiction:

Improveenergy efficiencyVSAvoidreliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The heat recovery function is segmented and distributed across three separate heat exchangers (first heat exchanger, second heat exchanger, third heat exchanger), each associated with a specific absorption stage. This segmentation ensures that if one heat recovery component fails, the other stages can continue to operate, thereby maintaining system reliability while still achieving overall energy efficiency improvements.

Inventive Principle:

Principle #1Segmentation

4Loss of energy

If quench venturi is used for intermediate absorption, then heat recovery is improved, but energy consumption increases

Engineering Contradiction:

Improveheat recoveryVSAvoidenergy consumption

Core Design Contradiction:

Loss of energyVSUse of energy by moving object

Solution Approach 1:

The system uses hydraulic principles with liquid acid sprays in packed bed absorbers instead of pneumatic quench venturi systems. This approach achieves effective heat recovery and absorption through liquid-gas contact in a controlled manner, avoiding the high energy consumption associated with forcing gases through quench venturi devices while still achieving superior heat recovery compared to conventional methods.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 significantly increases steam production by up to 30% and maintains energy efficiency even in high humidity conditions, reducing plant costs and operational complexity while using cost-effective materials for the pre-drying absorber.

Implementation Method 1

a pre-drying absorber for pre-drying humid air with weak sulfuric acid

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

a heat exchanger for enhanced steam production and energy recovery

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a two-stage sulfur trioxide absorption subsystem

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS10532929B2Energy efficient sulfuric acid system for humid environments

Publication Date: 2020.01.14 CHEMETICS INC

AI summary

A contact process, sulfuric acid system and method are disclosed for producing sulphuric acid with improved operating efficiency in humid environments. The system comprises a pre-drying absorber for pre-drying humid air with weak sulfuric acid. Weak sulfuric acid from the pre-drying absorber is provided to a subsystem comprising two sulfur trioxide absorbers and a heat exchanger for the recovery of heat via steam production. This arrangement allows for a marked increase in steam production (i.e. energy efficiency). In a separate improvement, the emission apparatus for the system can be simplified using a peroxide tail gas scrubber comprising upper and lower scrubber sections in which the upper scrubber section consists essentially of tray type scrubbers.