Heat Integration in Gas Processing Shift Reactors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated gasification combined cycle (IGCC) and substitute natural gas (SNG) plants face significant energy inefficiencies due to waste energy generation and high energy demands in gas treatment processes, particularly in converting carbonaceous feedstocks into syngas, where substantial steam is required and often wasted.
Innovation Solution
The implementation of heat integration within gas processing units, utilizing exothermic shift reactions to produce steam, which is then used as a heat transfer medium and power source, reducing the overall steam requirement by up to two-fold and minimizing irreversible heat losses through efficient heat recovery and utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat integration is implemented using exothermic shift reactions to produce steam, then energy efficiency is improved and steam consumption is reduced, but system complexity increases due to additional heat exchange equipment
Solution Approach 1:
The patent combines the steam generation function with the gas cooling function by integrating heat exchangers within the gas processing section. The exothermic heat from shift reactions is merged with the cooling requirement of the gas stream, allowing simultaneous steam production and gas temperature control through a unified heat integration system.
Solution Approach 2:
The heat exchangers serve multiple functions: they cool the hot gas stream from shift reactions, generate steam for process use, and preheat feed water. This multi-functionality reduces the need for separate equipment and improves overall energy utilization efficiency.
2Quantity of substance
If steam is generated from exothermic shift reactions, then steam requirement is reduced, but irreversible heat losses increase without proper heat recovery
Solution Approach 1:
The patent implements preliminary heat recovery by using heat exchangers to capture heat from the hot gas stream before it exits the system. This pre-recovery action prevents irreversible heat losses by utilizing the thermal energy while the gas is still at high temperature, generating steam that can be used elsewhere in the process.
Solution Approach 2:
The heat integration system maintains continuous useful action by constantly recovering heat from the gas stream and converting it to steam. This continuous process ensures that thermal energy is utilized throughout operation rather than being lost, maintaining energy efficiency consistently.
3Loss of energy
If multiple steam generators are installed between shift reactors, then heat recovery efficiency is improved, but device complexity and capital cost increase
Solution Approach 1:
The patent segments the heat recovery process into multiple stages by installing steam generators at different locations between shift reactors. Each steam generator handles a specific temperature range and process requirement, allowing optimized heat recovery at each stage while maintaining manageable system complexity through modular design.
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 enhances energy efficiency by reducing steam consumption, improving syngas treatment by removing undesirable materials, and enabling the export of excess steam for power generation, thereby optimizing energy use and reducing waste in IGCC and SNG systems.
Implementation Method 1
A first steam generator is disposed along the gas path between the first and second shift reactors, wherein the first steam generator is configured to transfer heat away from the gas path to generate a first steam
Implementation Method 2
an ammonia stripper configured to receive the first steam and a condensate from the gas path, wherein the ammonia stripper is configured to strip ammonia from the condensate using the first steam
Implementation Method 3
the first shift reactor is configured to perform a first shift reaction to produce a first shifted gas... the second shift reactor is configured to perform a second shift reaction to produce a second shifted gas
Data Source
AI summary
The present embodiments are directed towards heat integration in gas processing units. In one embodiment, a system is provided that includes a gas processing section. The gas processing section has a gas path, a first shift reactor disposed along the gas path, wherein the first shift reactor is configured to perform a first shift reaction to produce a first shifted gas. A second shift reactor is also disposed along the gas path downstream from the first shift reactor, wherein the second shift reactor is configured to perform a second shift reaction to produce a second shifted gas. A first steam generator is disposed along the gas path between the first and second shift reactors, wherein the first steam generator is configured to transfer heat away from the gas path to generate a first steam.