Superheating Dilution Steam via Gas Turbine Flue Gas
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Solution Overview
Problem
Current methods for generating and superheating dilution steam in steam cracking operations are energy intensive and lack efficient techniques, necessitating the development of improved methods for this process.
Innovation Solution
The method involves using compressed air to generate flue gas through a gas turbine generator, which is then used to superheat dilution steam within a steam cracking furnace, combining it with the hydrocarbon feedstock upstream of a radiant coil to enhance vaporization and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dilution steam is heated using coils or heat exchangers in the convection section, then dilution steam can be generated, but energy consumption increases
Solution Approach 1:
The patent combines the steam generation function with the electricity generation function by integrating a steam generator into the gas turbine exhaust system. The flue gas from the gas turbine is used to generate high-pressure steam, which then drives the turbine. This merging of functions eliminates the need for separate energy input for steam generation, thereby reducing overall energy consumption while maintaining steam production.
Solution Approach 2:
The system uses its own waste heat (flue gas from the gas turbine) to generate the steam needed for operation. The flue gas, which would otherwise be discarded, is utilized to heat water and generate steam in the steam generator. This self-service approach converts waste resources into useful energy, reducing external energy requirements.
2Productivity
If high temperature dilution steam is provided to promote complete vaporization, then vaporization efficiency improves, but energy intensity increases
Solution Approach 1:
The patent changes the temperature and pressure parameters of the steam by generating high-pressure steam from the flue gas heat. This high-pressure steam is then expanded through the turbine to produce electricity while maintaining sufficient temperature for effective vaporization. The parameter transformation allows the system to achieve both high vaporization efficiency and energy recovery.
Solution Approach 2:
The system maintains continuous useful action by using the flue gas heat continuously to generate steam, which continuously drives the turbine. This continuous process ensures that energy is constantly being converted from waste heat to useful mechanical work and electricity, maintaining high productivity without intermittent energy-intensive heating cycles.
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 efficiently superheats dilution steam, reducing the liquid fraction of the feed stream and increasing the production of desired products like ethylene while generating electricity, with the additional fuel used for electricity generation attributed to an efficiency of 60-80%.
Implementation Method 1
superheating dilution steam using the flue gas
Implementation Method 2
superheating dilution steam using the flue gas
Implementation Method 3
it can be desirable to provide high temperature dilution steam to promote complete vaporization
Data Source
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AI summary
Methods and systems for superheating dilution steam for use in a steam cracking furnace and generating electricity are provided. Methods can include combusting fuel in the presence of compressed air to produce a flue gas, wherein the flue gas drives a turbine to produce electricity. Methods can further include superheating the dilution steam with the flue gas, combining the dilution steam with a feed stream including hydrocarbons to produce a mixed feed stream, and steam cracking the mixed feed stream to produce a product stream.