Counter-Current Leaching of Drilling Residues
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Solution Overview
Problem
Current methods for disposing of drilling residues, such as drill cuttings and drilling fluids, are inefficient and costly due to the difficulty in separating soluble salts from finely divided solids, leading to environmental hazards and high disposal costs, as they require large amounts of water and result in significant waste volume increases.
Innovation Solution
A counter-current, multistage leaching system that separates soluble salts from finely divided solids using a combination of a multi-stage countercurrent leaching chamber, fluidized bed, and clarifier, minimizing water usage and producing high-concentration pregnant liquor for reuse or sale.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If batch-wise washing or dilution with fresh water is used to remove salts from fine solids, then salt removal is achieved, but very large quantities of water are consumed
Solution Approach 1:
The washing process is divided into multiple stages (typically 3-5 stages) with each stage performing a portion of the salt removal. This segmentation allows for more efficient water utilization by distributing the washing function across multiple contact points rather than requiring a single large-volume wash
Solution Approach 2:
Instead of washing solids with fresh water in a conventional direction, the system uses counter-current washing where fresh water enters at the last stage and contacts solids that have already been partially washed, while brine-rich solids from earlier stages move to subsequent washing stages. This inverted approach maximizes the washing efficiency of each unit of water
2Loss of substance
If multiple washing stages are used to reduce salt concentration, then salt removal efficiency improves, but the complexity of the washing and settling process increases
Solution Approach 1:
The washing and settling functions are merged into a single integrated device that performs both operations simultaneously. The washing zones are arranged vertically with settling zones, allowing solids to be washed and then settled in sequence without requiring separate equipment for each function
Solution Approach 2:
The multi-stage washing process is arranged in a vertical configuration rather than horizontal, utilizing the vertical dimension to stack multiple washing and settling stages. This dimensional reorganization allows for compact arrangement of multiple process stages while maintaining efficient counter-current flow patterns
3Stability of the object's composition
If drying agents such as fly-ash or cement kiln dust are added to solidify drilling residues, then solidification is achieved, but the mass and volume of material for transport and disposal increase
Solution Approach 1:
The system extracts and removes soluble salt components from the drilling residues through counter-current washing before solidification. By taking out the problematic soluble salts that prevent effective solidification, the remaining solids can be properly solidified without requiring excessive amounts of drying agents
Solution Approach 2:
The washing and salt removal process is performed as a preliminary step before solidification. This preliminary action removes the interstitial brine and soluble salts that would otherwise interfere with solidification, allowing the solidification process to be more efficient and require less additional material
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 achieves 98.8% to 99.4% chloride removal with reduced fresh water consumption, lowering disposal costs and enabling on-site treatment of drilling residues, while producing a reduced volume of high-value brine for re-use or sale.
Implementation Method 1
fluidizing the mixture to form a fluidized mixture that moves toward a top of the fluidized bed
Implementation Method 2
separating solids and liquids via multiple mixing and separating stages
Implementation Method 3
collecting and discharging pregnant liquor from a clarifier arranged atop both the fluidized bed and the multi-stage countercurrent leaching chamber
Data Source
AI summary
This disclosure describes systems, methods, and apparatus for counter-current solids leaching. A multi-stage countercurrent leaching chamber can include a top and bottom end, a barren liquor input, two or more regions for countercurrent mixing, and a barren solids output. The input can be configured to receive barren liquor. The two or more regions for countercurrent mixing and separation can be configured to mix and separate liquid and solid phases. The barren solids output can be configured to collect and discharge barren solids from the bottom end of the multi-stage countercurrent leaching chamber. A fluidized bed chamber and clarifier chamber can also be included, where the fluidized bed receives a fluidizable slurry of pregnant solids and the clarifier chamber aids in separating liquids from solids passing from a top of the fluidized bed chamber to the top end of the multi-stage countercurrent leaching chamber.