Oilfield Produced Water Treatment via Warm Lime Softening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The disposal of produced water from oil fields is challenging due to the presence of solutes, which requires effective treatment methods to meet state and federal regulations, particularly in California, where varying water quality standards complicate the standardization of treatment facilities.
Innovation Solution
A method and system involving a warm lime softener, microfiltration, reverse osmosis, and additional treatment steps such as ion exchange resin softening and air stripping to remove solutes and minerals, allowing for the recycling of sludge and adjustment of pH levels to achieve compliance with irrigation water regulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If produced water is injected underground at a remote site, then disposal is achieved, but transportation costs and environmental impact increase
Solution Approach 1:
The patent extracts and removes harmful solutes (minerals, organic compounds, boron) from produced water through a multi-stage treatment process including warm lime softening, microfiltration, and reverse osmosis. This extraction of contaminants enables the water to be discharged locally rather than requiring remote injection, eliminating transportation costs and associated environmental impacts.
Solution Approach 2:
The patent converts the harmful high-salinity produced water into a beneficial resource by treating it to meet irrigation water standards. The treated water can be reused for agricultural purposes, transforming a disposal problem into a water resource solution, particularly valuable in arid regions where water conservation is critical.
2Object-affected harmful factors
If produced water is treated for surface discharge, then environmental compliance is improved, but treatment complexity and cost increase
Solution Approach 1:
The patent divides the treatment process into distinct sequential stages: warm lime softening (removing calcium, magnesium, silica), microfiltration (removing particulates), and reverse osmosis (removing dissolved solids and boron). Each stage targets specific contaminants, making the overall complex treatment process more manageable and easier to operate while ensuring comprehensive compliance with discharge standards.
Solution Approach 2:
The patent utilizes parameter changes including temperature elevation in warm lime softening (improving precipitation efficiency), pH adjustment through lime addition (optimizing contaminant removal), and pressure differential across reverse osmosis membranes (enabling selective solute rejection). These parameter modifications enhance treatment effectiveness while maintaining system feasibility.
3Device complexity
If standard treatment facilities are used, then treatment process is simple, but compliance with varying state regulations becomes difficult
Solution Approach 1:
The patent employs adjustable and adaptable treatment parameters including variable pH control through lime dosing, adjustable filtration pressures, and flexible operational conditions for each treatment stage. This dynamic capability allows the system to be tuned to meet different state-specific regulations (e.g., California's stringent boron limits for irrigation water) while using standardized equipment, providing both simplicity and regulatory flexibility.
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 reduces solute levels in produced water to meet regulatory standards, enabling above-ground disposal and reducing operational costs by minimizing the need for magnesium additives and polymer use, while maintaining membrane integrity and preventing biofouling.
Implementation Method 1
passing an aqueous liquid containing dissolved minerals and dissolved hydrocarbons through a warm lime softener at a pH of about 11
Implementation Method 2
passing the effluent through a microfiltration system
Implementation Method 3
contacting the effluent from the microfiltration system with a reverse osmosis system
Implementation Method 4
passing an effluent from the reverse osmosis system through an air stripper
Implementation Method 5
an ion exchange resin based softener in fluid communication with a microfiltration system
Data Source
AI summary
The invention relates to a method and system for treating an aqueous liquid containing dissolved minerals and dissolved hydrocarbons. Method steps and apparatus for treating a waste water feed stream are disclosed which utilize a warm lime softening system in fluid communication with the waste water feed stream, wherein sludge from the warm lime softening system is recycled to improve lime utilization and enhance silica and boron removal without the addition of an external source of magnesium. In addition, a microfiltration system and/or an air stripper system may be used in fluid communication with at least one reverse osmosis system to produce a treatment water that meets state and federal guidelines for surface discharge.