Desalter Interface Rag Removal via Toroidal Water Flow
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Solution Overview
Problem
The accumulation of a solid-laden 'rag' layer at the oil-water interface in desalter vessels hinders water and solids separation, leading to reduced desalter performance, increased fouling of heat exchangers, and upset conditions in refineries, as existing mud wash systems are inadequate in addressing this issue.
Innovation Solution
A system involving a piping circuit with nozzles arranged to inject water at a low velocity, promoting a toroidal rotation of the brine water layer to suspend solids and collapse the interface rag layer, thereby preventing build-up and maintaining efficient desalter operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If periodic mud wash is used to remove solids, then mud accumulation is reduced, but water treatment facility is overwhelmed by high levels of oil wet solids causing upset conditions
Solution Approach 1:
The interface rag is removed continuously before it accumulates to problematic levels. By maintaining continuous removal action through the rag removal system, the system prevents the harmful effect of periodic mud wash overloads on the water treatment facility.
Solution Approach 2:
The rag removal system operates continuously rather than periodically, maintaining steady-state removal of interface rag. This continuous action prevents the accumulation of solids that would otherwise be discharged in periodic mud washes, ensuring stable operation of the water treatment facility.
2Reliability
If semi-continuous mud wash is used to level solids load, then water treatment facility load is distributed, but solids still accumulate in vessel bottom requiring periodic washing
Solution Approach 1:
The system extracts and removes the interface rag layer continuously, separating it from the main vessel contents. This extraction prevents solids from accumulating in the vessel bottom, eliminating the need for periodic mud washes to remove settled solids.
3Productivity
If interface rag accumulates at oil-water interface, then separation rate is slowed, but electrostatic field strength is reduced and current demand increases
Solution Approach 1:
The rag removal system operates continuously to maintain steady-state removal of interface rag, preventing accumulation that would interfere with the electrostatic field. This continuous action maintains both separation efficiency and field integrity simultaneously.
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 solution continuously agitates the interface rag layer, suspends solids in the water, and reduces mud accumulation, improving separation efficiency, minimizing emulsion buildup, and protecting process equipment from fouling, thus extending planned crude unit run-length and maintaining water quality.
Implementation Method 1
injecting a water flow through a plurality of nozzles arranged about a piping circuit so that a volume of water in the brine water layer rotates, thereby uniformly suspending solids in the brine water and promoting a collapse of the interface rag layer
Data Source
AI summary
A method and system for controlling an interface emulsion layer and mud layer within a desalter vessel includes injecting a water flow through a plurality of nozzles arranged about a piping circuit located in the brine water layer. Each nozzle is oriented toward an interior space of the desalter vessel and is arranged oblique to the piping circuit. The water flow through the plurality of nozzles causes a horizontal and vertical rotation of a volume of water that is effective for suspending solids in the water and promoting a collapse of the interface emulsion layer. The water velocity through each nozzle, which may be a recycled water flow, is preferably in a range of 1 to 3 fpm and each nozzle is preferably oriented at an angle of about 15° and 60° in a horizontal plane and a downward angle of about 15° and 60° in a vertical plane.