Bi-modal Drag Reducer Particle Distribution for Pipeline Dissolution
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Solution Overview
Problem
Existing polymeric drag reducing agents for hydrocarbons face challenges such as cold flow, degradation, and the need for specialized equipment due to particle size and stability issues, leading to inefficient drag reduction over the length of pipelines.
Innovation Solution
The use of bi-modal or multi-modal particle size distributions in polyolefin drag reducing compositions, allowing for tailored dissolution rates to provide effective drag reduction throughout the pipeline by combining smaller and larger particles, which dissolve quickly and sustainably, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ground polymer particles are used as drag reducing agents, then they can be pumpable and free-flowing, but they cold flow or stick together after passage of time, making it impossible to place them in the hydrocarbon where drag is to be reduced in a form of suitable surface area and particle size that will dissolve or mix with the hydrocarbon in an efficient manner
Solution Approach 1:
The invention changes the particle size distribution parameters by using a bi-modal distribution with two distinct peaks at different size ranges. This allows the mixture to maintain pumpability while preventing cold flow, as the smaller particles act as spacers between larger particles. The specific parameter change from monomodal to bi-modal distribution resolves the contradiction between ease of operation and compositional stability.
Solution Approach 2:
The invention creates a composite particle system by combining two different polymer particle size populations in a specific ratio. This composite approach allows the smaller particles to prevent agglomeration of larger particles while both contribute to drag reduction effectiveness, resolving the contradiction between pumpability and particle size stability over time.
2Productivity
If the polymer is ground to smaller particle sizes to improve dissolution, then dissolution efficiency increases, but the grinding process or mechanical work employed in size reduction tends to degrade the polymer, thereby reducing the drag reduction efficiency
Solution Approach 1:
The invention segments the polymer population into two distinct size groups rather than using a single size distribution. The smaller segment (first size range) provides rapid dissolution without requiring excessive grinding that would degrade the polymer, while the larger segment (second size range) maintains structural integrity and drag reduction effectiveness. This segmentation resolves the contradiction between dissolution rate and polymer integrity.
3Productivity
If gel or solution DRAs are used to achieve rapid dissolution, then they dissolve quickly in hydrocarbon, but they demand specialized injection equipment and pressurized delivery systems
Solution Approach 1:
The invention changes the physical state parameter from gel/solution form to a dry powder formulation with bi-modal particle size distribution. This parameter change allows the material to be handled as a free-flowing powder without requiring specialized injection equipment or pressurized delivery systems, while still achieving rapid dissolution through the smaller particle size population.
4Stability of the object's composition
If conventional DRAs are transported in carrier fluid at low polymer concentration (about 10% maximum), then the polymer can be delivered, but up to about 90% of the volume being transported and handled is inert material, making transportation costs considerable
Solution Approach 1:
The invention utilizes a phase transition approach by suspending dry polymer particles in a minimal amount of carrier fluid rather than dissolving the polymer to form a gel or solution. This allows the polymer to be transported in a semi-solid slurry form with much higher effective concentration, eliminating the need to transport large volumes of inert carrier fluid while maintaining stability through the bi-modal particle size distribution that prevents agglomeration.
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 ensures consistent drag reduction performance over long distances, reducing the need for specialized equipment and minimizing inert material transportation costs, while maintaining polymer stability and efficiency.
Implementation Method 1
smaller and larger particles, which dissolve quickly and sustainably, respectively
Data Source
AI summary
Drag reduction of hydrocarbon fluids flowing through pipelines of various lengths is improved by polyolefin drag reducer dispersions or dispersions using bi- or multi-modal particle size distributions. Drag reducers having larger particle sizes dissolve more slowly than drag reducers having smaller particle sizes. By using at least bi-modal particle size distributions drag reduction can be distributed more uniformly over the length of the pipeline where smaller sized particles dissolve sooner or earlier in the pipeline and larger sized particles dissolve later or further along the pipeline.