Prilling Tower Funnel Structure Eliminates Scraper Friction
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Solution Overview
Problem
The prilling process for producing urea faces issues such as caking, friction-related abrasion, and high energy consumption due to the use of mechanical scrapers and humidity, which affect the quality and efficiency of the final product.
Innovation Solution
A prilling tower with a funnel-shaped conveying structure at the bottom, eliminating the need for mechanical scrapers and increasing air inflow, reduces friction, mechanical defects, and energy costs, while improving the dimensional distribution and quality of urea prills.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mechanical scraper is used to remove solid product from the bottom of the tower, then the solid product can be conveyed toward the outlet opening, but friction and abrasion of the urea occur, increasing energy consumption and reducing product quality
Solution Approach 1:
The patent removes the mechanical scraper entirely from the system, extracting the harmful element that causes friction and abrasion. The scraper is replaced with a funnel-shaped conveying structure that uses gravity and air flow to move solid particles without mechanical contact, thereby eliminating the harmful friction and abrasion effects while maintaining productivity.
Solution Approach 2:
The mechanical scraper system is replaced with a pneumatic-gravitational conveying system. The funnel-shaped structure combined with upward air flow creates a fluidized bed environment where particles are suspended and conveyed by air currents and gravity rather than mechanical scraping, substituting mechanical action with pneumatic and gravitational forces.
2Productivity
If a mechanical scraper is used to move solid product, then conveying function is provided, but energy consumption increases due to operation of the scraper
Solution Approach 1:
The energy-consuming mechanical scraper is replaced with a passive funnel-shaped structure that relies on gravity and pneumatic forces for particle conveyance. The upward air flow naturally suspends and transports particles through the funnel without requiring mechanical work, dramatically reducing energy consumption while maintaining conveying productivity.
Solution Approach 2:
The conveying system becomes self-service through the natural interaction of gravity and air flow. The funnel structure automatically directs particles downward while the upward air flow suspends and transports them, creating a self-sustaining conveying mechanism that requires minimal external energy input compared to active mechanical scraping.
3Productivity
If mechanical scraper and humidity are present in the system, then solid product can be collected, but caking phenomenon occurs affecting product quality
Solution Approach 1:
The patent removes the mechanical scraper that contributes to caking by creating friction and localized compression. By eliminating this mechanical contact element, the system reduces one of the key factors causing caking, while the funnel structure and air flow system continue to enable effective solid product collection.
Solution Approach 2:
The system uses pneumatic principles to counteract caking. The upward air flow creates fluidization that prevents particles from settling and compacting into cakes. The pneumatic suspension keeps particles separated and in motion, preventing the adhesion and compression that lead to caking, while still allowing effective collection through the funnel structure.
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
The solution enhances the quality and efficiency of urea production by eliminating scraper-related issues, reducing energy consumption, and optimizing air flow, resulting in improved product quality and reduced production costs.
Implementation Method 1
air (normally at ambient temperature) is supplied into the bottom of the tower, and rises in countercurrent flow to the liquid phase, causing the formation of generically spherical agglomerated particles
Implementation Method 2
with the increase of the effective height resulting from the introduction of a funnel-shaped structure with several sectors (with consequent increased quantity of air supplied)
Data Source
Figure 1~2
Figure 3
AI summary
A prilling tower (1), in particular for producing ·urea, comprises: a casing (2) extending along and about an axis (A) and provided with an inner treatment chamber (4); a sprayer device (7) arranged at a top axial end (5) of the casing (2) for supplying a liquid phase in the chamber (4); windows (11) set at a bottom axial end (8) of the casing (2) for supplying air inside the chamber (4); and a conveying structure (9) arranged at the bottom axial end (8) of the casing. (2) for collecting prills formed in the chamber (4); the conveying structure (9) is formed by a plurality of flared sectors (20), arranged in series along the axis (A) and converging downwards and towards the axis (A); the sectors (20) are partially inserted inside one another both axially and radially and have respective inner lateral surfaces. (29) slanted so as to cause the prills, deposited on the inner lateral surfaces (29), to slide for the sole effect of gravity towards the bottom outlet (12).