Slurry Drying Plant Using Meshing Screw Conveyors

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Solution Overview

Problem

Existing slurry drying technologies are expensive to manufacture and operate, and they do not efficiently address the challenges of handling, storing, and disposing of organic slurry due to high water content, potential contamination, and odor or gas emissions.

Innovation Solution

A slurry drying plant with two meshing screw conveyors and superheated steam at atmospheric pressure is used to efficiently dry the slurry, where the screw conveyors are designed with helical blades running in opposite directions to enhance heat transfer and distribution, and the steam is directed opposite to the slurry flow for optimal drying, with subsequent thermal processing to convert the slurry into harmless coke.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional drying methods are used, then drying capability is achieved, but manufacturing cost and operating cost are high

Engineering Contradiction:
Improvedrying capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The drying system is segmented into multiple independent screw conveyors that can be arranged in series, allowing modular construction and flexible scaling. Each screw conveyor operates as an independent drying zone, enabling cost-effective manufacturing while maintaining reliable drying capability through distributed processing stages

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Superheated steam is introduced as an intermediary heating medium that transfers thermal energy to the slurry through the screw conveyor structure. This indirect heating approach via steam intermediary achieves effective drying while avoiding direct flame contact, reducing manufacturing complexity and operating costs compared to direct combustion systems

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conventional drying methods are used, then drying capability is achieved, but operating cost is high

Engineering Contradiction:
Improvedrying capabilityVSAvoidoperating cost
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system utilizes parameter changes in the superheated steam (temperature, pressure, enthalpy) as it progresses through the series of screw conveyors. The steam parameters are optimized at each stage to maximize heat transfer efficiency, reducing total energy consumption while maintaining effective drying capability across all processing zones

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The superheated steam undergoes phase transition from vapor to liquid as it condenses while heating the slurry. This phase change releases latent heat energy that is efficiently transferred to the moisture in the slurry, significantly reducing the operating energy cost compared to systems that do not utilize condensation heat

Inventive Principle:
Principle #36Phase transitions

3Device complexity

If single screw conveyor is used, then结构简单 is achieved, but heat transfer efficiency is low

Engineering Contradiction:
Improvestructure complexityVSAvoidheat transfer efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The drying system is divided into multiple screw conveyors arranged in series, creating segmented drying zones. Each screw conveyor provides additional heat transfer surface area and processing time, significantly improving overall heat transfer efficiency while maintaining relatively simple individual component structures that are easy to manufacture and maintain

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The series arrangement of multiple screw conveyors ensures continuous heat transfer action throughout the entire drying process. The slurry progresses sequentially through each heating zone, receiving continuous thermal energy input without interruption, which maximizes heat transfer efficiency while keeping each individual screw conveyor structurally simple

Inventive Principle:
Principle #20Continuity of useful action

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 results in a cost-effective, efficient drying process that reduces water content, eliminates contaminants, and converts slurry into a safe, usable fertilizer, while also reusing surplus heat and minimizing environmental impact.

Implementation Method 1

passing superheated steam substantially at atmospheric pressure past the slurry

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

when subsequently condensing the steam, the surplus heat can be reused

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

it hereby is possible to knead and divide the slurry during the conveying process and thus ensure a larger heat transferring surface

Methodology Applied
Scientific EffectMechanical kneading and division: Mechanical Force

Data Source

PatentEP3580509B1A slurry drying plant, a method for drying slurry and use of a slurry drying plant
Publication Date: 2024.09.25 AQUAGREEN LICENSE APS
  • EP3580509B1 patent drawingFigure 1
  • EP3580509B1 patent drawingFigure 2~3

AI summary

Disclosed is a slurry drying plant (1) comprising a slurry inlet (2) for feeding slurry to the slurry drying plant (1) and two or more meshing screw conveyors (3, 4) arranged to at least partly divide the slurry while conveying the slurry in a transport direction from the slurry inlet (2) to a slurry outlet (5). The slurry drying plant (1) further includes slurry heating means (6) comprising means for passing superheated steam substantially at atmospheric pressure past the slurry and the two or more meshing screw conveyors (3, 4), while they are conveying the slurry. Furthermore, a method for drying slurry and use of a slurry drying plant (1) is disclosed.