Steam Reforming Plant Segmented Steam Generation for Shift Conversion
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Solution Overview
Problem
Existing processes for producing synthesis gas fail to effectively separate pure steam from process condensate, leading to contamination of export steam with impurities and inadequate steam supply for water gas shift reactions, while also lacking control over the steam/dry gas molar ratio in shift conversion units.
Innovation Solution
A process that generates two separate steam streams - pure steam from boiler feed water and process steam from evaporated condensate - using a common PC-boiler for cooling synthesis gas, with both streams being added to the shift conversion units to optimize the steam/dry gas ratio and maintain steam quality, thereby avoiding contamination and ensuring sufficient steam supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If process condensate is used to generate steam for export, then steam supply is increased, but steam quality deteriorates due to impurity contamination
Solution Approach 1:
The patent segments the steam generation system into two separate steam streams: a pure steam stream from boiler feed water and a process steam stream from process condensate. This segmentation allows each stream to serve its specific purpose - pure steam for export and process steam for internal process use - thereby maintaining steam quality while increasing overall steam supply.
Solution Approach 2:
The patent merges the two separate steam streams (pure steam and process steam) in the shift conversion units to achieve the desired steam/dry gas molar ratio. This combining approach allows the system to benefit from both high steam supply from process condensate and high steam quality from boiler feed water, resolving the contradiction between quantity and purity.
2Productivity
If steam is added to shift conversion units to optimize steam/dry gas ratio, then reaction efficiency is improved, but steam quality may deteriorate due to impurity mixing
Solution Approach 1:
The patent segments the steam addition process by providing separate steam streams to the shift conversion units - one from pure steam and one from process steam. This allows optimization of the steam/dry gas ratio for reaction efficiency while maintaining the option to use high-quality pure steam, thus resolving the contradiction between productivity and steam quality.
3Device complexity
If a single steam stream is used for both export and process use, then system complexity is reduced, but steam quality control becomes difficult
Solution Approach 1:
The patent implements segmentation by creating separate steam generation paths - one from boiler feed water for export steam and another from process condensate for process steam. Although this increases structural complexity, it enables independent quality control of each stream, resolving the contradiction between system simplicity and steam quality control.
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 increases steam availability for water gas shift conversion, enhances plant flexibility and control, and maintains high steam quality by separating pure and process steam streams, optimizing the steam/dry gas ratio and reducing impurity impact.
Implementation Method 1
process steam stream which is generated by evaporating at least a portion of the process condensate by the cooling of synthesis gas
Implementation Method 2
cooling of synthesis gas in step ii) is the cooling of a synthesis gas stream exiting said first or second shift conversion unit
Implementation Method 3
cooling at least a portion of said pure steam stream as heat exchange medium
Implementation Method 4
catalytic water-gas shift (WGS) conversion stage comprising the use of one or more water-gas shift conversion units
Data Source
AI summary
Process and plant for producing a synthesis gas by catalytic steam reforming of a hydrocarbon feedstock in a steam reforming unit, further comprising a first and second shift conversion unit, wherein water is removed from the synthesis gas as a process condensate, wherein boiler feed water is introduced in the process, and wherein said process or plant produces at least two separate steam streams: a pure steam which is generated from at least a portion of said boiler feed water by the cooling of synthesis gas, and a process steam which is generated by evaporating at least a portion of the process condensate in a process condensate boiler (PC-boiler) by using synthesis gas, optionally together with pure steam and/or flue gas from the steam reforming unit. Process steam, and pure steam other than that from the PC boiler, are added to the first shift conversion unit, optionally also to the second second shift conversion unit.