Degasifying Membrane Module for Process Water Purification
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Solution Overview
Problem
Existing water treatment processes for power plants, particularly those using flue gas desulfurization and gasification wastewaters, face challenges in consistently meeting stringent EPA limits for constituents like selenium, arsenic, and nitrate, with variability in water composition and temperature sensitivity affecting process performance, and conventional evaporative processes producing distillate water with high ion concentrations.
Innovation Solution
The method involves filtering process water through a degasifying membrane module to reduce dissolved gas concentrations before evaporating, using a degasifying membrane module with a pressure differential to diffuse gases into a vacuum chamber, followed by evaporation at reduced pressure and temperature to achieve low ion concentrations in the water vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional evaporative processes are used to treat process water, then water purification is achieved, but the distillate water contains high ion concentrations that fail to meet EPA limits
Solution Approach 1:
The patent applies preliminary action by removing dissolved gases from process water before evaporation through a degasifier unit. This pre-treatment step prevents gas interference during subsequent evaporation, enabling consistent production of distillate water with ion concentrations below EPA limits while improving reliability of the purification process
Solution Approach 2:
The patent replaces conventional high-temperature evaporative systems with a low-temperature evaporation system operating below 212°F. This substitution uses controlled heating with heat exchangers and vacuum conditions to achieve purification at lower temperatures, improving both manufacturing precision of ion removal and reliability of meeting discharge requirements
2Manufacturing precision
If treatment processes are designed to meet strict EPA limits, then water quality improves, but process complexity and operational challenges increase
Solution Approach 1:
The patent merges multiple treatment functions into an integrated system where the degasifier and evaporator units work in sequence as a unified process. The degasifier removes dissolved gases and the evaporator concentrates ions in a single continuous flow path, achieving EPA-compliant water quality while reducing operational complexity compared to separate treatment trains
Solution Approach 2:
The patent applies parameter changes by operating the evaporation process at low temperatures below 212°F under controlled pressure conditions. This parameter modification allows effective ion removal and water purification while simplifying equipment requirements and reducing operational complexity compared to high-temperature conventional evaporation systems
3Manufacturing precision
If existing treatment systems are used, then current water quality standards are met, but they cannot consistently achieve the lower ion concentrations required by new EPA proposals
Solution Approach 1:
The patent applies preliminary action by removing dissolved gases from process water before evaporation through a degasifier unit. This pre-treatment step prevents gas interference during subsequent evaporation, enabling consistent production of distillate water with ion concentrations below EPA limits while improving reliability of the purification process
Solution Approach 2:
The patent replaces conventional high-temperature evaporative systems with a low-temperature evaporation system operating below 212°F. This substitution uses controlled heating with heat exchangers and vacuum conditions to achieve purification at lower temperatures, improving both manufacturing precision of ion removal and reliability of meeting discharge requirements
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 reduces dissolved ion concentrations in the treated water, meeting EPA limits and producing high-purity water suitable for reuse or discharge, with improved resilience to process upsets and variability, and minimal reagent and maintenance requirements.
Implementation Method 1
diffusing at least a portion of the dissolved gas in the process water across the membrane and into the vacuum chamber to remove at least a portion of the first dissolved gas from the process water
Implementation Method 2
a vacuum chamber at a second pressure that is less than the first pressure
Implementation Method 3
evaporating the filtered process water to create a water vapor
Implementation Method 4
evaporation at reduced pressure and temperature
Data Source
AI summary
Disclosed are methods for purifying a process water, which can comprise providing a process water comprising a first concentration of a first dissolved gas and a first concentration of a first dissolved ion, filtering the process water to create a filtered process water comprising a second concentration of the first dissolved gas, and evaporating the filtered process water to create a water vapor comprising a second concentration of the first dissolved ion that is less than the first concentration of the first dissolved ion.