Rotating Cylindrical Screen for Drilling Mud Separation
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Solution Overview
Problem
Current methods for separating drill cuttings from drilling mud on offshore rigs are inefficient and environmentally harmful, with existing technologies being costly, difficult to scale, or causing environmental pollution due to limitations in processing capacity and throughput.
Innovation Solution
A system comprising a rotatable cylindrical screen with a wash unit that uses a surfactant solution to separate drill cuttings from drilling mud, allowing for efficient separation and recycling of mud, with a centrifuge unit for further processing to achieve low oil content in cuttings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation methods (centrifugation, drying) are used to reduce mud content, then oil content in cuttings can be reduced to about 5%, but the equipment struggles with blockages, screen binding-up, and throughput-related issues
Solution Approach 1:
The separation process is divided into distinct functional zones along the screen: a washing zone where surfactant solution is applied to loosen mud, a separation zone where the screen physically separates cuttings from fluid, and a discharge zone. This segmentation allows each zone to optimize for its specific function, preventing blockages while maintaining high throughput.
Solution Approach 2:
A surfactant solution is introduced as an intermediary substance that mediates between the hydrophobic drilling mud and the hydrophilic screen surface. The surfactant reduces surface tension, allowing the screen to effectively capture and separate mud particles from cuttings without causing binding-up or blockages, thus maintaining both separation precision and throughput.
2Manufacturing precision
If vibrating banana screens with partial vacuum are used, then some mud removal is achieved, but only a small area of cuttings is exposed to the washing action, limiting efficiency and processing throughput
Solution Approach 1:
The invention transitions from a two-dimensional screen surface to a three-dimensional cylindrical rotating screen. This dimensional change allows the washing action to envelop cuttings from multiple angles (inner and outer surfaces of the cylinder), dramatically increasing the exposed surface area for mud removal while maintaining continuous rotation for high throughput processing.
Solution Approach 2:
The rotating cylindrical screen provides continuous washing action as cuttings rotate through the surfactant solution, eliminating the intermittent contact of stationary screens. This continuous useful action ensures consistent mud removal efficiency while the rotation enables high processing throughput by continuously presenting fresh cuttings to the washing zone.
3Manufacturing precision
If cuttings are processed through multiple stages (centrifugation, drying), then oil content is reduced, but the equipment becomes complex and difficult to operate on offshore rigs
Solution Approach 1:
The invention merges multiple separation functions into a single integrated rotating screen apparatus. The washing, separation, and dewatering functions that would traditionally require separate centrifugal and drying equipment are combined into one unit, reducing overall system complexity while maintaining effective oil content reduction to below 5%.
Solution Approach 2:
The rotating cylindrical screen serves multiple functions simultaneously: it acts as a washing surface for surfactant application, a separation surface for mud-cuttings separation, and a conveyance mechanism for moving cuttings through the system. This multi-functionality eliminates the need for multiple separate pieces of equipment, reducing complexity for offshore operation.
4Productivity
If large-scale processing is implemented, then processing throughput increases, but existing technologies become expensive and difficult to apply on a large scale
Solution Approach 1:
The rotating cylindrical screen configuration allows for dynamic scaling of processing capacity by adjusting rotation speed, surfactant flow rate, and screen dimensions. This dynamic adaptability enables the system to scale throughput from small to large volumes without requiring fundamentally different equipment designs, making large-scale application cost-effective and straightforward.
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 the oil content in drill cuttings to less than 5%, enabling efficient processing and recycling of drilling mud, while allowing for continuous operation at high throughput rates, thus addressing environmental concerns and improving waste management.
Implementation Method 1
a wash unit for delivering a wash agent to the particles, wherein delivery of the wash agent to the particles assists with separation of the particles from the flowable substance
Implementation Method 2
the screen allows for passage of the flowable substance therethrough, and defines a path for passage of the particles between the inlet and the outlet
Implementation Method 3
a centrifuge unit for separating phases of a solution or mixture comprising at least a portion of the flowable substance that has passed through the screen
Data Source
AI summary
An apparatus for separating particles, such as drill cuttings, from a flowable substance, such as drilling mud, is provided. The apparatus comprises an inlet for entry of particles combined with the flowable substance; an outlet for exit of particles separated from the flowable substance; a movable screen located between the inlet and the outlet; and a wash unit for delivering a wash agent to the particles. The screen allows for passage of the flowable substance therethrough, and defines a path for passage of the particles between the inlet and the outlet. Delivery of the wash agent to the particles assists with separation of the particles from the flowable substance. Associated systems and methods are also provided.