Urea Plant CO2 Compressor Gas Turbine Integration
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Solution Overview
Problem
Urea production plants face inefficiencies in energy consumption due to high energy demands for compressing carbon dioxide to synthesis pressure and suboptimal use of low-pressure, low-temperature steam, which is not easily exploitable for heat purposes.
Innovation Solution
Integration of a gas turbine to operate the CO2 compressor and a heat recovery steam generator using exhaust gases from the gas turbine to produce steam for the high-pressure stripper, effectively utilizing low-pressure steam and reducing energy consumption by using the gas turbine's mechanical power and heat efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a CO2 compressor is operated directly by a steam turbine or electric motor, then the compressor can supply CO2 to the synthesis section, but the energy consumption is high and the steam system integration is suboptimal
Solution Approach 1:
The patent merges the CO2 compressor operation with a gas turbine that utilizes exhaust gases from other plant operations. The gas turbine drives the CO2 compressor while its exhaust heat is recovered in a heat recovery steam generator, combining mechanical power generation and heat recovery into a single integrated system that reduces overall energy consumption.
Solution Approach 2:
The gas turbine system serves multiple functions: it provides mechanical power to drive the CO2 compressor and simultaneously generates steam through its heat recovery steam generator. This multi-functional approach allows the same energy source to address both mechanical power needs and steam requirements, optimizing the overall steam system integration.
2Loss of energy
If low-pressure steam is produced in the condenser, then condensation heat is utilized, but the steam cannot be easily exploited for heat purposes due to low temperature and pressure levels
Solution Approach 1:
The heat recovery steam generator acts as an intermediary device that receives low-pressure steam from the condenser and uses it to heat water, generating usable process steam. This intermediary system transforms the low-quality heat energy into higher-quality process steam that can be effectively utilized in the synthesis section, bridging the gap between condensation heat and process heat requirements.
Solution Approach 2:
The system changes the parameters of the low-pressure steam by using it to heat water in the heat recovery steam generator, transforming it into steam at different pressure and temperature levels suitable for process applications. This parameter transformation makes the previously unusable low-pressure steam valuable for heating the synthesis section.
3Quantity of substance
If external steam is imported or an auxiliary steam generator is introduced to offset steam shortage, then steam requirements are met, but fuel consumption increases and costs rise
Solution Approach 1:
The plant achieves self-service for steam requirements by internally generating sufficient steam through the heat recovery steam generator that utilizes exhaust heat from the gas turbine. This self-sufficient approach eliminates or reduces the need for external steam imports and auxiliary fuel-consuming steam generators, making the plant energy-independent for its steam needs.
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 optimizes energy use by providing mechanical power for the CO2 compressor and thermal energy for the stripper, efficiently utilizing low-pressure steam and reducing overall energy consumption, thus enhancing the integration of the steam system with the urea synthesis process.
Implementation Method 1
a gas turbine for the operation of said CO2 compressor
Implementation Method 2
a gas turbine for the operation of said CO2 compressor
Implementation Method 3
a heat recovery steam generator, wherein the heat source of said heat recovery steam generator consists of the exhaust gases of said gas turbine
Implementation Method 4
one or more steam turbines are used. A steam turbine may drive directly a machine (for example a compressor or a pump)
Data Source
AI summary
Plant for the synthesis of urea, comprising: a synthesis section comprising at least one reactor, a compressor for supplying CO2 to said synthesis section, a gas turbine for the operation of said CO2 compressor and a heat recovery steam generator; the heat source of said heat recovery steam generator consists of the exhaust gases of said gas turbine, and at least one steam flow produced by said heat recovery steam generator is used as heat source for at least one component of said urea plant.