Iso-butane Additive for Low-Pressure Hydrate Desalination

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Solution Overview

Problem

Current desalination methods, such as distillation and reverse osmosis, are energy-intensive and costly, while hydrate-based desalination requires high pressures, making it uneconomical due to the need for high pressure for hydrate formation.

Innovation Solution

Incorporating iso-butane as an additive in the hydrate formation process to reduce the pressure required for hydrate formation, allowing for the separation of seawater or wastewater into cleaner water and gas, using a hydrate former reactor and decomposition unit to control temperature and pressure for efficient hydrate slurry formation and separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrate formation is used for desalination, then salt rejection and water purification are achieved, but high pressure requirements make the process uneconomical

Engineering Contradiction:

Improvesalt rejection efficiencyVSAvoidpressure requirement

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent changes the pressure parameter by introducing iso-butane additive, which shifts the hydrate formation equilibrium conditions. This allows hydrate formation to occur at lower pressures (e.g., 30-50 bar instead of 100-200 bar) while maintaining effective salt rejection, directly resolving the contradiction between purification efficiency and pressure requirement

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Iso-butane acts as an intermediary substance that mediates between water and gas to form hydrates at reduced pressure conditions. The additive modifies the hydrate formation mechanism, enabling the process to achieve salt rejection without requiring excessively high pressures, thus resolving the economic viability issue

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If high pressure is applied for hydrate formation, then hydrate slurry formation is achieved, but energy consumption increases

Engineering Contradiction:

Improvehydrate formation efficiencyVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

By changing the pressure parameter through additive introduction, the patent reduces the energy input required for compression while maintaining hydrate formation efficiency. The iso-butane additive allows the system to operate at lower pressures, directly reducing the energy consumption associated with high-pressure operation

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional desalination methods are used, then water purification is achieved, but process cost and energy intensity are high

Engineering Contradiction:

Improvewater purification effectivenessVSAvoidprocess cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the operational parameters (pressure and temperature) by using iso-butane additive, enabling hydrate-based desalination to compete economically with conventional methods. The modified parameters reduce both energy consumption and equipment requirements, lowering overall process cost while maintaining purification effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical membrane system of reverse osmosis with a chemical-based hydrate formation system. This substitution eliminates membrane fouling issues and allows operation at lower pressures, reducing both capital and operational costs while achieving equivalent or superior purification

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 decreases the energy requirements for hydrate formation, enabling efficient desalination of seawater or wastewater with reduced pressure, allowing for the production of cleaner water with lower dissolved salt concentrations, and recycling iso-butane for cost-effectiveness.

Implementation Method 1

contacting, within a hydrate former reactor, a feed gas stream including iso-butane... and liquid seawater or liquid wastewater including a dissolved salt, wherein a temperature and pressure within the hydrate former reactor is controlled so that the feed gas stream and the liquid seawater or liquid wastewater form a hydrate slurry

Methodology Applied

Scientific EffectHydrate formation: Hydrates

Implementation Method 2

decomposing the hydrate particles into its constituents of water and gas or gas mixture containing iso-butane

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS11292730B2Hydrates for water desalination using iso-butane additive

Publication Date: 2022.04.05 EXXONMOBIL TECHNOLOGY & ENGINEERING CO

AI summary

A method for desalinating a liquid, including: contacting, within a hydrate former reactor, a feed gas stream including iso-butane in an amount ranging from above zero mol % to about 3 mol % and liquid seawater or liquid wastewater including a dissolved salt, wherein a temperature and pressure within the hydrate former reactor is controlled so that the feed gas stream and the liquid seawater or liquid wastewater form a hydrate slurry; separating hydrate particles from the hydrate slurry; and decomposing the hydrate particles into its constituents of water and gas or gas mixture containing iso-butane, wherein the water has a concentration of the dissolved salt that is less than that of the liquid seawater or liquid wastewater.