Starch-Based Flocculant Composition for Fracturing Flowback Treatment
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Solution Overview
Problem
Current treatments for fracturing flowback fluid, particularly using polyaluminum chloride and polyacrylamide, are inefficient and environmentally harmful due to poor flocculation effects and slow biodegradation of polyacrylamide, leading to challenges in managing the high viscosity, salt content, and emulsification of this waste fluid.
Innovation Solution
A flocculant prepared by dissolving gelatinized starch with unsaturated polyethylene glycol, unsaturated short-chain carboxylic acid, and hydroxyethyl methacrylate phosphate under a nitrogen atmosphere, followed by reaction and purification, which enhances flocculation and biodegradability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyacrylamide is used as flocculant, then flocculation effect is improved, but biodegradation rate deteriorates
Solution Approach 1:
The patent uses composite materials by combining gelatinized starch (natural polymer) with grafted acrylamide and acrylic acid units. This creates a semi-synthetic flocculant that maintains the biodegradability of starch while incorporating the effective flocculation properties of acrylamide-based polymers. The starch backbone provides biodegradability pathways while the grafted chains deliver flocculation performance.
Solution Approach 2:
The patent changes the molecular structure parameters by controlling the grafting degree and molecular weight of the flocculant. By optimizing these parameters, the flocculant achieves effective flocculation performance while maintaining a molecular structure that is more amenable to biodegradation compared to conventional high molecular weight polyacrylamide.
2Ease of manufacture
If polyaluminum chloride is used as flocculant, then preparation simplicity is improved, but flocculation effect deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by using natural starch as the base polymer and grafting acrylamide and acrylic acid onto it. This approach maintains relative simplicity in raw material acquisition while achieving superior flocculation performance through controlled chemical modification, producing a semi-synthetic polymer with optimized properties.
3Object-generated harmful factors
If conventional starch-based flocculant is used, then biodegradability is improved, but solubility and dissolution rate deteriorate
Solution Approach 1:
The patent changes the physical and chemical parameters of starch by gelatinization (heating to 60-80°C for 30-120 minutes) and chemical grafting. These modifications improve solubility and dissolution rate while maintaining the starch backbone that ensures biodegradability. The gelatinization process opens the starch structure, and grafting introduces hydrophilic groups that enhance water solubility.
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 flocculant effectively reduces turbidity, color, suspended matters, COD, and total iron in fracturing flowback fluid while minimizing environmental impact through biodegradability and simple preparation.
Implementation Method 1
adding starch into water, uniformly stirring, heating to a gelatinization temperature (usually 60-80° C.), keeping the temperature for 30-120 min
Implementation Method 2
adding unsaturated polyethylene glycol, unsaturated short-chain carboxylic acid, hydroxyethyl methacrylate phosphate and an initiator under a nitrogen atmosphere for reaction
Implementation Method 3
The flocculant effectively reduces turbidity, color, suspended matters, COD, and total iron in fracturing flowback fluid
Data Source
AI summary
Disclosed are a flocculant for treating fracturing flowback fluid and a preparation method therefor, which relate to oilfield sewage treatment. The method includes: in parts by weight, dissolving gelatinized starch in water, adding unsaturated polyethylene glycol, unsaturated short-chain carboxylic acid, hydroxyethyl methacrylate phosphate and an initiator under a nitrogen atmosphere for reaction for 3-8 h, and after the reaction is completed, separating and purifying to obtain a product. The flocculant for treating fracturing flowback fluid is prepared by a one-pot method, and the solvent is water, so that the preparation method is simple and has better environmental protection performance; meanwhile, the flocculant not only can reduce turbidity, color and suspended matters of the flowback fluid, but also can effectively reduce COD and total iron of the flowback fluid, and also can reduce the mineralization to a certain degree. The flocculant has good biodegradability and has less impact on the environment.