Produced Water Treatment via Membrane Filtration and Coalescing
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Solution Overview
Problem
Current methods for treating produced water from oil and gas fields are inefficient in removing oil and suspended solids, leading to high operating costs, revenue losses, and potential plugging issues during Enhanced Oil Recovery (EOR) processes, as they generate excessive by-products and are sensitive to contaminants.
Innovation Solution
Implementing an Ultrafiltration (UF) or Microfiltration (MF) membrane system followed by an out-in tubular or hollow fiber coalescing contactor to produce an oil-free effluent, where emulsified oil droplets are coalesced from the shell to the tube side, allowing for pure oil recovery and minimizing membrane fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flotation devices with high dosing rates of coagulant aid chemicals are used to remove oil and solids, then oil-water separation is improved, but operating costs increase and coagulated sludge byproduct is generated
Solution Approach 1:
The invention extracts and removes the harmful coagulant aid chemicals from the treatment process entirely, replacing them with a chemical-free membrane filtration system that achieves oil-water separation without generating coagulated sludge byproduct or requiring chemical dosing
Solution Approach 2:
The invention replaces the mechanical/chemical flotation system with a membrane-based physical separation system that uses filtration mechanisms rather than chemical coagulation, eliminating the need for coagulant aid chemicals and reducing operating costs
2Loss of substance
If liquid/liquid coalescing devices are used to coalesce and recover oil, then oil recovery is improved, but the process becomes sensitive to suspended solids and loses robustness
Solution Approach 1:
The invention segments the treatment process into two distinct stages: first removing suspended solids through membrane filtration, then recovering oil through coalescing on the membrane surface, preventing solids from interfering with the coalescing process
Solution Approach 2:
The invention performs preliminary removal of suspended solids through ultrafiltration/microfiltration before the oil coalescing step, ensuring that the coalescing membrane is not blocked or interfered with by solids, thus maintaining robustness
3Reliability
If Ultrafiltration or Microfiltration membranes are used to remove water insoluble oil, then effluent quality is improved, but oily concentrate byproduct is generated that causes membrane fouling when recirculated
Solution Approach 1:
The invention converts the harmful oily concentrate that would normally cause fouling into a beneficial oil recovery stream by using the concentrate as feed for the coalescing contactor, where oil is recovered and the deoiled concentrate is recirculated back to the membrane system without causing fouling
Solution Approach 2:
The invention discards the problematic oily concentrate from the membrane system and recovers the oil through the coalescing contactor, then returns the deoiled concentrate to the membrane feed, eliminating the fouling issue while recovering valuable oil
4Reliability
If conventional pretreatment methods are used to remove suspended solids and oil, then treatment is achieved, but high volumes of byproducts are generated inducing high operating costs
Solution Approach 1:
The invention recovers oil from what would normally be a waste byproduct stream (the concentrate) and returns the deoiled water to the treatment process, minimizing waste volumes and enabling byproduct reuse
Solution Approach 2:
The invention changes the state of the concentrate stream by adjusting pH and adding salts to promote oil coalescence, transforming a fouling-prone oily concentrate into a source of recoverable oil and deoiled water
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 effectively removes over 99% of non-polar oil, recovers over 80% as a pure oil stream, and reduces by-product volumes, preventing plugging and revenue losses, while ensuring robustness against suspended solids, thus enhancing the economic viability of water reuse in EOR processes.
Implementation Method 1
an first step of ultra- or micro-filtration of the liquid
Implementation Method 2
an first step of ultra- or micro-filtration of the liquid
Implementation Method 3
a second step of coalescing a concentrate obtained from said first step by mean of a coalescing contactor
Data Source
AI summary
A process of treating a liquid containing oil and solids, includes an ultra- or micro-filtration step followed by a coalescing step of the concentrate obtained from the filtering step by uses of a coalescing contactor.