Internal Tank Flash Separator to Reduce Crude Oil Vapor Pressure Cost
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Solution Overview
Problem
Existing methods for conditioning crude oil to remove volatile hydrocarbons, such as those from the Bakken region, are costly and inefficient, especially during colder months due to high gas-to-oil ratios and varying temperatures, making it difficult to meet safety standards for railroad transport.
Innovation Solution
An internal tank separator apparatus is used that retains enthalpy to enhance flash vaporization of lighter hydrocarbons, featuring a storage container tank with an inner pipe, distribution screen for single-stage flash evaporation, and a packed bed for additional separation, allowing the warm conditioned hydrocarbon product to act as a thermal insulator for incoming crude oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional conditioning equipment (stripper column or absorber/stripper column) is used to limit vapor pressure, then vapor pressure is reduced, but equipment cost increases significantly
Solution Approach 1:
The internal tank separator divides the flash vaporization process into multiple stages using distribution screens at different heights and a packed bed section. The crude oil is separated into vapor and liquid phases at each stage, with vapors rising through the packed bed for additional separation. This segmented approach achieves effective vapor pressure reduction using simple, low-cost components rather than expensive traditional conditioning equipment.
Solution Approach 2:
The internal tank separator apparatus is nested within the existing storage tank, with the inner pipe containing distribution screens and packed bed positioned inside the outer pipe which forms the tank wall. This nested configuration allows the flash vaporization system to be integrated into the storage tank structure itself, eliminating the need for separate conditioning equipment and reducing overall system cost.
2Object-affected harmful factors
If crude oil is routed to a common stabilizer, then vapor pressure is controlled, but pipeline and right of way costs increase
Solution Approach 1:
The storage tank and flash vaporization separator are merged into a single integrated system. The internal tank separator apparatus is installed directly in the storage tank, combining the storage function with the vapor pressure control function. This eliminates the need for separate conditioning equipment and associated pipeline infrastructure, reducing both equipment and pipeline costs.
3Object-affected harmful factors
If flash vaporization is used to remove lighter hydrocarbons, then vapor pressure is reduced, but heat transfer losses occur in colder months
Solution Approach 1:
The packed bed serves as an intermediary medium between the rising vapor phase and the surrounding environment. It provides thermal insulation and allows heat exchange between the vapor stream and the liquid crude oil flowing down the annular space, reducing heat losses to the environment during colder months while maintaining effective flash vaporization.
Solution Approach 2:
The system maintains continuous flash vaporization operation year-round by utilizing the thermal energy retained in the crude oil stream. The annular downward flow path allows warm crude oil to continuously flow down around the inner pipe, providing ongoing heat retention and reducing energy losses during colder months.
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 effectively reduces Reid vapor pressure year-round at lower costs compared to conventional methods, ensuring safer crude oil transport without the need for expensive equipment, and maintains efficiency across varying temperatures.
Implementation Method 1
a distribution screen located near or top of the apparatus, wherein the distribution screen provides an interface for single stage flash evaporation upon spray, impingement and/or agitation of the hydrocarbon product
Implementation Method 2
a secondary area for vapor-liquid separation located below the distribution screen in the annular space between the inner and outer pipes, wherein the secondary area includes a packed bed that provides additional separation of components of the hydrocarbon product
Implementation Method 3
an annular downward flow path for the processed hydrocarbon product, which provides a barrier against heat transfer between incoming hydrocarbon product in the inner pipe and bulk surrounding fluid stored in the container tank
Data Source
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AI summary
A method for separating lighter components of a hydrocarbon product in a container tank includes introducing the hydrocarbon product into the container tank via an inlet located near or at the bottom of the container tank; routing the hydrocarbon product through a pipe-in-pipe conduit that is at least partially surrounded by a bulk fluid stored in the container tank; providing a vapor-liquid interface that allows efficient evaporation of the lighter components resulting in separation of the lighter components and a processed hydrocarbon product; and routing the processed hydrocarbon product into the annular space of the pipe-in-pipe conduit thereby thermally insulating incoming hydrocarbon product from the surrounding bulk fluid and eliminating or minimizing vapor liquid equilibrium shift of the incoming hydrocarbon product caused by increased head pressure and/or reduction in temperature of the incoming hydrocarbon product.