Sulfate Removal via Divalent Ion Seeding and Barite Precipitation
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Solution Overview
Problem
Current methods for removing sulfate ions from seawater or saline water are economically expensive and inefficient, particularly in the oilfield industry, where scale formation due to sulfate reduction can impair production and require costly membrane technologies or reverse osmosis systems.
Innovation Solution
A method involving seeding seawater rich in sulfate ions with divalent ions to form barite crystals, which are then separated, using a reaction unit and separator to reduce sulfate concentration, with anti-adhesion coatings to prevent scaling on equipment surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane technologies or reverse osmosis are used to remove sulfate ions, then sulfate removal effectiveness is improved, but operational cost and equipment complexity increase significantly
Solution Approach 1:
The patent replaces complex mechanical membrane systems with a simple chemical precipitation process. Instead of using reverse osmosis membranes requiring high pressure and complex filtration systems, the invention uses divalent ion seeding to precipitate sulfate as barite crystals, which can be removed through simple sedimentation and filtration, dramatically reducing equipment complexity while maintaining sulfate removal effectiveness
Solution Approach 2:
The patent changes the chemical parameters of the brine by adding divalent ions (barium, calcium, or strontium) to shift the sulfate removal mechanism from physical filtration to chemical precipitation. This parameter change allows sulfate to be removed through solubility product principles rather than membrane filtration, simplifying the overall system
2Reliability
If membrane technologies or reverse osmosis are used to remove sulfate ions, then sulfate removal effectiveness is improved, but operational cost increases
Solution Approach 1:
The patent uses inexpensive divalent ion salts (barium chloride, calcium chloride, or strontium chloride) as seeding agents that can be added in small quantities to trigger precipitation. These cheap chemical additives replace expensive membrane systems, making the process economically viable for oilfield operations where cost-effectiveness is critical
Solution Approach 2:
The precipitation process is self-sustaining once seeding begins. The added divalent ions automatically react with sulfate to form insoluble barite crystals that precipitate out of solution, requiring minimal external energy input or complex control systems, thereby reducing operational costs compared to energy-intensive reverse osmosis
3Quantity of substance
If seawater is used as base liquid during stimulation operations, then water availability is improved, but scale formation impairs production
Solution Approach 1:
The patent applies preliminary action by removing sulfate ions from the brine before it is injected into the formation. By pre-treating the injection fluid to precipitate and remove sulfate, the system prevents scale formation from occurring in the first place, eliminating the need for expensive post-treatment scale remediation operations
Solution Approach 2:
The patent converts the harmful sulfate ions into beneficial barite crystals through controlled precipitation. The sulfate, which would otherwise cause scale formation and production impairment, is transformed into removable solid crystals that can be easily separated from the injection fluid, turning a production problem into a simple separation task
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 method effectively and economically reduces sulfate ions in seawater, preventing scale formation and allowing for the conversion of seawater into low-salinity water, suitable for use in the oilfield, desalination, and food industries, while minimizing bacterial growth and operational costs.
Implementation Method 1
seeding seawater rich in sulfate ions with divalent ions to form barite crystals
Implementation Method 2
separating the stream into an effluent and a fluid comprising less sulfate than the stream
Data Source
AI summary
Methods and apparatus of embodiments of the invention relate to treating water including contacting a liquid stream with a source comprising inorganic and/or divalent ions and separating the stream into an effluent and a fluid comprising less sulfate than the stream, wherein the effluent comprises more sulfate and more inorganic and/or divalent ions than the stream. Methods and apparatus relate to treating water including a reaction unit comprising an inlet for feed fluid and an inlet for inorganic and/or divalent ions and a separator unit comprising an inlet for output from the reaction unit, an outlet for effluent, and an outlet for fluid comprising less sulfate than the feed fluid. Some embodiments include introducing the fluid comprising less sulfate than the stream into a subterranean formation.