Urea Plant Evaporation Loop for Dust Scrubbing Energy Reduction
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Solution Overview
Problem
Urea production plants face high energy consumption and equipment investment costs due to the need for extensive steam usage in condensate treatment and water handling, particularly in the dust scrubbing and process condensate treatment sections.
Innovation Solution
Incorporating an additional evaporation loop with a second evaporation section and condensation section downstream of the dust scrubbing section, utilizing the condensed liquids for dust scrubbing and bypassing the process condensate treatment section, thereby reducing steam requirements and equipment dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional dust scrubbing and condensate treatment sections are used, then dust removal and ammonia recovery are achieved, but steam consumption and energy cost increase significantly
Solution Approach 1:
The invention extracts the dust scrubbing function from the conventional condensate treatment system by introducing a separate dust scrubbing section with water spray nozzles. This separates the dust removal function from the steam-based condensate treatment, allowing dust to be removed without consuming process steam, thereby resolving the contradiction between effective dust removal and high steam consumption.
Solution Approach 2:
The invention segments the gas treatment process into distinct functional sections: a dust scrubbing section for particle removal using water spray, and a separate condensate treatment section for ammonia recovery. This segmentation allows each section to operate with optimized steam consumption, with the dust scrubbing section using minimal steam compared to the conventional integrated system.
2Reliability
If extensive steam usage is applied in condensate treatment and water handling, then ammonia recovery efficiency is improved, but equipment investment costs and energy consumption increase
Solution Approach 1:
The invention divides the gas treatment system into separate dust scrubbing and condensate treatment sections, each optimized for its specific function. The condensate treatment section maintains sufficient steam usage for effective ammonia recovery, while the dust scrubbing section uses minimal steam, reducing overall equipment size and investment costs while preserving ammonia recovery efficiency.
Solution Approach 2:
The invention applies different treatment qualities to different sections: the dust scrubbing section uses water spray with minimal steam for particle removal, while the condensate treatment section uses optimized steam injection for ammonia recovery. This localized optimization reduces overall equipment complexity while maintaining high ammonia recovery efficiency in the critical condensate treatment zone.
3Object-generated harmful factors
If water spray amount is increased in dust scrubbing, then dust removal efficiency is improved, but steam consumption in subsequent treatment increases
Solution Approach 1:
The invention segments the water management into dust scrubbing water and condensate treatment steam as separate streams. The dust scrubbing section uses water spray for particle capture, and the resulting wastewater is treated separately with controlled steam injection. This segmentation allows optimization of each section independently, achieving good dust removal without unnecessarily increasing steam consumption in the condensate treatment section.
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 configuration significantly reduces energy consumption and investment costs by minimizing steam use and water treatment volumes, allowing for increased urea production capacity without extensive modifications.
Implementation Method 1
In the evaporation section (B), said solution (3) is separated into a (liquid) concentrated urea melt (4) and a gaseous stream (11)... The evaporation section is operated under vacuum conditions.
Implementation Method 2
The evaporation section is operated under vacuum conditions.
Implementation Method 3
A additional condensation section (H) is provided downstream of the dust scrubbing section (D)... wherein the additional condensation section (H) is in fluid communication with the dust scrubbing section (D).
Implementation Method 4
The main function of this finishing section is to transfer the urea melt (4) into a stream of solidified particles (5)... to transfer the urea from the liquid phase into the solid phase, the heat of crystallization has to be removed. Moreover, usually some additional heat is removed from the solidified urea particles, in order to cool them to a temperature that is suitable for safe and comfortable storage and transport of this final product.
Implementation Method 5
In the dust scrubbing section (D), dust scrubbing is usually done using a circulating urea solution as washing agent. On top of this also fresh water scrubbing usually is applied. The air entering via (7), by its nature of cooling air in finishing section (C), is hot. Therefore a considerable amount of water will evaporate in the dust scrubbing section D.
Data Source
Figure 1
Figure 2
AI summary
Disclosed is a plant for the production of urea. The plant comprises conventional sections for synthesis and recovery, for evaporation and condensation, for urea finishing, and for dust scrubbing. According to the invention, an additional evaporation and condensation loop is introduced from and to the dust scrubbing section. This loop results in a more favorable energy consumption of the plant.