Double Drum Biosolids Drying With Nip Feeding to Prevent Bridging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing double drum dryers face limitations in processing biosolids due to their inability to handle biosolids that are too dry or stiff to slip through the nip, which causes bridging or stiff, resulting in inefficient throughput and moisture content, and the inability to efficiently convert biosolids to fertilizer, which are not fluid enough to flow through the nip, leading to bridging and reduced drying efficiency.
Innovation Solution
A novel system combining pre-screening, chemical flocculation, dewatering, double drum steam impulse drying, and flash evaporation, along with a feeding chamber and nip feeder, to enhance the flowability of biosolids and improve throughput in the drying process, allowing for efficient conversion to Class A fertilizer without the need for aerobic or anaerobic digestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If double drum dryers are used to dry biosolids, then moisture content is reduced, but throughput is limited due to bridging when biosolids become too dry or stiff
Solution Approach 1:
A feed chamber is positioned above the nip area to pre-position biosolids before they enter the drying zone. This preliminary action ensures biosolids are properly located and prevents bridging by maintaining continuous flow into the nip, resolving the contradiction between drying effectiveness and throughput
Solution Approach 2:
A nip feeder acts as an intermediary device between the feed chamber and the nip area. It receives biosolids from above and actively feeds them into the nip gap, ensuring continuous material flow even when biosolids become stiff or dry, thereby maintaining throughput while allowing effective drying
2Ease of operation
If biosolids are sprayed with pendulum slurry feed system or pumped into the nip, then drying process can operate, but biosolids that are too stiff or dry will bridge over the nip and not effectively pass through
Solution Approach 1:
Instead of pumping biosolids into the nip from below (traditional method), the invention positions the feed chamber above the nip area and uses gravity assisted feeding. This inverted approach allows biosolids to be fed downward into the nip, preventing bridging and improving effective throughput while maintaining ease of operation
Solution Approach 2:
The invention replaces the pendulum slurry feed system or pump-based mechanical feeding with a gravity-assisted feed chamber and nip feeder mechanism. This substitution eliminates the bridging problem associated with traditional mechanical feeding methods while maintaining operational simplicity
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 system increases the efficiency and productivity of biosolid processing, reducing operational costs and time, and enables the production of high-quality Class A fertilizer with enhanced drought durability and nutrient content, overcoming the limitations of traditional double drum dryers.
Implementation Method 1
double drum steam impulse drying
Implementation Method 2
steam impulse drying
Implementation Method 3
flash evaporation
Data Source
AI summary
A system for converting biosolids to fertilizer comprising: a storage tank for holding biosolids; a plurality of conveyors for conveying the biosolids, from the storage tank to a pressurized screener, then to a centrifuge, then to a feeding chamber, to deliver the biosolids to a nip feeder and then to first and second dryer drums operatively positioned to rotate and draw biosolids into the nip, first and second scrapers are operably positioned to remove biosolids from the first and second dryer drums as they rotate, the first and second dryer drums are selectively heated with steam provided by a boiler.