Lock-Hopper Pressure Equalization Using Product Gas
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Solution Overview
Problem
Existing methods for operating descending moving bed reactors with flowable granular material face challenges such as high purge gas consumption, formation of flammable gas mixtures, and product contamination due to inefficient pressure equalization and gas handling in lock-hoppers.
Innovation Solution
The method involves synchronously or offset filling and emptying upper and lower lock-hoppers with granular material, recirculating purge gas to minimize consumption, and using product gas for pressure equalization and relieving, while preventing flammable mixture formation by controlling oxygen concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressurized inert gas is used for purging and pressure equalization of lock-hoppers, then pressure difference bridging is achieved, but gas consumption and compression power requirements increase significantly
Solution Approach 1:
The patent recycles the inert purge gas from the lock-hoppers back to the storage hopper instead of discarding it. The gas that was used for purging and pressure equalization is captured and reused for the next filling cycle, significantly reducing overall gas consumption and eliminating the need for continuous compression power.
Solution Approach 2:
The system uses the own purge gas from the lock-hoppers to service the storage hopper filling process. The recycled gas serves dual purposes: maintaining inert atmosphere and providing pressure equalization, making the system self-sufficient and reducing external resource requirements.
2Reliability
If lock-hoppers are purged with pressurized inert gas, then atmosphere bridging is achieved, but formation of flammable gas mixtures cannot be excluded
Solution Approach 1:
The patent maintains a continuous inert atmosphere in the lock-hoppers by recycling the inert gas. This prevents the formation of flammable mixtures by ensuring that oxygen concentration remains below combustion thresholds throughout the solid transfer process, eliminating the safety hazard while maintaining reliable atmosphere bridging.
3Productivity
If solid transfer is conducted through lock-hoppers with pressure equalization, then solid feeding is achieved, but product contamination occurs
Solution Approach 1:
The patent recycles the gas phase from the lock-hoppers containing any entrained product particles back to the reaction chamber or processing system. This recovery approach prevents product loss through contamination while maintaining continuous solid feeding operations.
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 approach reduces purge gas consumption, minimizes product contamination, and enhances the efficiency of gas handling, allowing for gravity-driven solid transport without the need for a carrier gas circuit, thereby improving the economic and operational efficiency of the reactor.
Implementation Method 1
allowing for gravity-driven solid transport without the need for a carrier gas circuit
Data Source
AI summary
A method can be used for operating a descending moving bed reactor with flowable granular material. The method involves: (i) filling an upper lock-hopper with granular material and/or emptying a lower lock-hopper, (ii) purging the lock-hoppers with purging gas, and (iii) filling the reaction chamber containing a descending moving bed from the upper lock-hopper and/or emptying the reaction chamber into the lower lock-hopper. The pressure equalization between the reaction chamber and lock-hopper is achieved with product gas. The method then involves: (iv) optionally, relieving the lock-hoppers and conveying the product gas flow into the product line, and (v) purging the lock-hoppers with purging gas.