Ejector Desalination Heat Integration Without Auxiliary Steam
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Solution Overview
Problem
Conventional thermal desalination processes require auxiliary steam for start-up and normal operations, necessitating fossil-fuel boilers that incur air emissions and permit challenges, especially in facilities without steam production or environmentally sensitive areas.
Innovation Solution
A low energy ejector desalination system using a static liquid-gas ejector and maximum heat integration, eliminating the need for auxiliary steam by employing a static liquid-gas ejector and integrating heat recovery within the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal desalination processes use auxiliary steam for start-up and normal operations, then the system can achieve reliable desalination performance, but it requires fossil-fuel boilers that produce air emissions and create permit challenges
Solution Approach 1:
The patent extracts and eliminates the auxiliary steam generation system (boiler) from the desalination process by using a heat pump system that recovers heat from the condenser and uses it to preheat feed water and generate steam, thereby removing the source of air emissions while maintaining desalination reliability
Solution Approach 2:
The patent recovers waste heat from the condenser that would otherwise be discarded, using it to preheat feed water and generate steam through the heat pump system, thereby eliminating the need for fossil-fuel boilers and their associated emissions
2Quantity of substance
If a boiler is installed to produce auxiliary steam, then steam availability is ensured, but the system complexity and permit requirements increase
Solution Approach 1:
The heat pump system performs multiple functions: it acts as a compressor, heat exchanger, and steam generator simultaneously, eliminating the need for separate boiler equipment while ensuring steam availability for the desalination process
Solution Approach 2:
The patent merges the steam generation function into the existing heat pump system by integrating the condenser heat recovery with the evaporator, thereby combining multiple functions into a single system and reducing overall complexity
3Loss of energy
If maximum heat integration is implemented in the desalination system, then energy efficiency is improved, but the system design complexity increases
Solution Approach 1:
The heat pump system enables continuous heat recovery and utilization throughout the desalination process, with the condenser heat continuously preheating feed water and the evaporator continuously generating steam, eliminating energy losses while maintaining manageable system design through standardized components
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 system effectively treats wastewater without auxiliary steam, reducing emissions and permit requirements, while enhancing efficiency and reducing system footprint through heat integration and static ejector technology.
Implementation Method 1
a heat exchanger to heat a wastewater stream and create a two-phase stream
Implementation Method 2
a column in fluid communication with the heat exchanger for separating the two-phase stream into a vapor distillate stream and a concentrated liquid wastewater stream
Implementation Method 3
an ejector in fluid communication with the column for combining the vapor distillate stream from the column and a liquid distillate stream to produce an ejector two-phase stream
Implementation Method 4
a separator in fluid communication with the ejector that separates the ejector two-phase stream into another vapor distillate stream and the liquid distillate stream
Implementation Method 5
a pump in fluid communication with the ejector to send the liquid distillate stream as a motive fluid to the ejector
Data Source
Figure 1
AI summary
Systems and methods for treating a raw wastewater feed stream using a low energy ejector, which works as a heat pump to increase the pressure and temperature of a two-phase distillate stream used, in part, to heat the raw wastewater feed stream. The systems and methods utilize heat from a liquid distillate stream and a concentrated liquid wastewater stream to pre-heat the raw wastewater feed stream and produce a liquid distillate product stream.