Electrocoagulation and Membrane Distillation for Produced Water Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The oil and energy industry faces challenges in treating produced water for steam generation due to high silica and hardness levels, which lead to scale formation and inefficiencies in steam generators, and existing reverse osmosis methods are energy-intensive and prone to fouling.
Innovation Solution
A system combining electrocoagulation, high-temperature filtration, and membrane distillation or forward osmosis to remove silica, hardness, and organic contaminants from produced water, using ceramic or polymeric membranes, and configuring the units for sequential or parallel operation to optimize treatment efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse osmosis membranes are used to reduce silica and hardness to negligible concentrations, then water quality for steam generation is improved, but energy consumption and pumping costs increase significantly
Solution Approach 1:
The treatment process is divided into multiple stages: electrocoagulation for initial silica and hardness removal, followed by membrane distillation or forward osmosis for final polishing. This segmentation allows each stage to target specific contaminants with appropriate technology, reducing overall energy consumption compared to using reverse osmosis for complete treatment.
Solution Approach 2:
The invention changes the operating parameters by using membrane distillation or forward osmosis instead of reverse osmosis. These alternative membrane processes operate at different pressure and temperature conditions, requiring less energy while achieving the same water quality standards for steam generation.
2Object-affected harmful factors
If produced water is treated to remove contaminants, then scale formation in steam generators is reduced, but treatment process complexity increases
Solution Approach 1:
Electrocoagulation acts as an intermediary treatment step that removes a significant portion of silica and hardness ions before the water enters the membrane distillation or forward osmosis unit. This preliminary treatment reduces the contaminant load on the membrane process, improving its effectiveness while managing overall system complexity.
Solution Approach 2:
The electrocoagulation unit serves multiple functions: it removes silica, removes hardness ions, and reduces organic content. This multi-functionality consolidates several treatment objectives into a single process step, reducing the number of separate units needed and simplifying the overall treatment train.
3Productivity
If high pressure steam is injected for heavy oil recovery, then oil viscosity is reduced and production is improved, but water treatment requirements increase due to scale formation risks
Solution Approach 1:
The treatment system performs preliminary removal of scale-forming contaminants (silica and hardness) through electrocoagulation before the water enters the membrane distillation or forward osmosis unit. This preliminary action ensures that water of sufficient quality is produced to prevent scale formation in steam generators, maintaining reliability while supporting high productivity EOR operations.
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 silica and hardness levels, improves steam generator efficiency, and reduces energy consumption by minimizing the need for heat exchangers, while maintaining high water quality for steam generation.
Implementation Method 1
The produced water is subject to an electrocoagulation process to remove at least a portion of the silica and hardness ions as suspended solids
Implementation Method 2
The pre-treated water is further treated in a direct contact membrane distillation (DCMD) unit, generating treated water having less than 10 mg/L TOC, less than 50 ppm silica, and less than 10 ppm hardness ions
Implementation Method 3
DCMD is a separation process that uses a temperature gradient across a hydrophobic membrane to separate vapor from liquid
Implementation Method 4
In another aspect, the invention relates to a system for treating produced water containing contaminants selected from the group of dissolved organics, free oil and grease, and TDS as silica and hardness ions
Data Source
AI summary
The invention relates to the treatment of water, including for example treatment in connection with hydrocarbon production operations. Silica in water produces undesirable scaling in processing equipment, which causes excess energy usage and maintenance problems. Electrocoagulation (EC) at relatively high water temperature, followed by any of membrane distillation or forward osmosis (FO), may be combined with a subsequent process of ceramic ultra-filtration (UF filtration) employed to treat water. Water to be treated may be produced water that has been pumped from a subterranean reservoir. The treated water may be employed to generate steam. The treatment units (e.g., EC, forward osmosis, UF filtration, etc) can be configured into one system as an on-site installation or a mobile unit for on-site or off-site water treatment.