Orifice Chamber Flow Developer for Flue Gas Pressure Reduction
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Solution Overview
Problem
In circulating fluidized bed catalytic cracking units, accommodating additional orifice plates in the orifice chamber for pressure reduction during revamp applications is challenging due to limited space for inspection and maintenance, leading to increased load on the double disc slide valve and potential erosion.
Innovation Solution
The orifice chamber design includes a flow developer means with circumferentially oriented vanes or a constricted section with tapered exits to achieve fully developed flow in a shorter distance, allowing for the accommodation of additional auxiliary orifice plates and increased pressure drop without compromising the clearance gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If additional orifice plates are installed in the existing orifice chamber to reduce pressure during revamp applications, then the pressure drop capability is improved, but the space for inspection and maintenance is reduced
Solution Approach 1:
The patent introduces a flow developer means that creates a radial flow component, effectively utilizing the radial dimension of the orifice chamber. This allows the flow to be fully developed in a shorter axial distance, enabling additional orifice plates to be installed along the axial direction without compromising the radial clearance needed for inspection and maintenance.
2Stability of the object's composition
If the flow length in the initial portion of the orifice chamber is increased to achieve fully developed flow, then the flow development is improved, but the space available for orifice plates is reduced
Solution Approach 1:
The patent segments the flow development process by introducing a flow developer means with circumferentially oriented vanes. This device breaks down the long axial flow development distance into shorter segments by creating radial flow components, allowing fully developed flow to be achieved in a compact axial space that can accommodate multiple orifice plates.
3Productivity
If the double disc slide valve opening is increased to handle higher pressure, then the throughput is improved, but the velocity increases causing increased erosion
Solution Approach 1:
The patent applies preliminary action by installing auxiliary orifice plates upstream in the orifice chamber to pre-reduce the pressure and velocity of the flue gas before it reaches the double disc slide valve. This preliminary pressure reduction allows the valve to operate at lower velocities even when handling higher throughput, thereby reducing erosion while maintaining productivity.
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 design enables the accommodation of more orifice plates, reducing the need for additional orifice chambers and minimizing wear on the double disc slide valve, while achieving the required pressure drop during revamp applications.
Implementation Method 1
The flue gas leaving the flue gas line forms a jet in the initial portion of orifice chamber and subsequently disperses across the orifice chamber and a fully-developed flow region is achieved
Implementation Method 2
Each orifice chamber is equipped with one or more orifice plates, and typically it has a minimum of two and a maximum of seven orifice plates in order to progressively take small pressure drops across the orifice plates
Data Source
AI summary
An apparatus and a method for achieving progressive reduction of flue gas is disclosed. Accordingly, an aspect of the present invention is to provide an apparatus comprising of an orifice chamber having an inlet pipe for receiving the flue gas, a flow region defined downstream of an exit of the inlet pipe and having at least a first section and a second section, and an outlet pipe to disperse a pressure reduced flue gas. The first section defined downstream of the inlet pipe has a flow developer means and at least one auxiliary orifice plate. The second section defined downstream of the first section has a plurality of orifice plates spaced apart along a flow length of the second section.