Publication detail
Research and Development of Heat Exchanger 'Water-Sludge'
KILKOVSKÝ, B. BORÁŇ, J. STRAŇÁK, Z. HOUDKOVÁ, L. JEGLA, Z. STEHLÍK, P.
Czech title
Výzkum a vývoj výměníku tepla "voda-kal"
English title
Research and Development of Heat Exchanger 'Water-Sludge'
Type
conference paper
Language
en
Original abstract
Heat exchanger 'water-sludge' (screw type heat exchanger) is mainly used for indirect sludge preheating at waste water treatment plants. Preheated sludge is pipelined into the digestion tanks, where anaerobic stabilisation is under way. A similar heat exchanger ''flue gas-sludge'' is being developed for the purpose of utilizing the available heat coming from sludge incineration. Principal advantages of this design are as follows: low energy consumption for sludge transport and easy access to the sludge side. The aim of this study is to describe the creation of a mathematical model of a heat exchanger, which will be used to monitor the influence of temperature on dewatering of mixed raw sludge. For this specific task a made-to-measure heat exchanger had to be designed. From the possible choices, a helical plate heat exchanger was chosen. The advantage of this type of an exchanger is a small built-up area, a high heat transfer area and easy maintenance and cleaning on the side of the sludge. Another advantage is a helical flow, which has a positive effect on self cleaning abilities. However, pressure losses would be higher than at direct (straight) canals. The increase of pressure loss is accompanied by an increased coefficient of heat exchange a. After the design of the exchanger measurements from a pilot unit would be obtained. On the base of them, the relations will be revised, if required. If sludge preheating shows to be advantageous for dewatering an exchanger of a ''fuel gas-sludge'' type would be designed in the next phase.
Czech abstract
Výměník tepla 'voda-kal' (šroubovicový typ výměníku tepla)je převážně používán pro nepřímí předehřev kalu odpadní vodou. Předehřátý kal je veden potrubím do vyhnívacích nádrží, kde probíhá anaerobní stabilizace. Pdobný výměník tepla "spaliny-kal" je vyvýjen pro záměr utilizace využití spalin vzniklých spalováním kalu. Základní výhody tohoto návrhu jsou následující: nízká spotřeba energie pro transport kalu a jednodušší přístup na straně kalu. Cílem tohoto článku je popsat matematický model výměníku tepla, který bude sloužit k určení vlivu teploty na odvodnění směsného surového kalu. Pro tento specifický účel byl navržen speciální výměník tepla. Z možných typů výměníků byl nakonec vybrán šroubovicový výměník tepla. Výhodou tohoto typu výměníku tepla je malá zastavěná plocha, vysoký součinitel prostupu tepla a snadné čištění na straně kalu. Další výhodou je šroubovicový tok, který mý pozitivní vliv na samočistící schoponost. Avšak tlakové ztráty budou větší než u přímích kanálů. Zvýšení tlakové ztráty je však vyvážené zvýšením součinitelů přestupu tepla.
English abstract
Heat exchanger 'water-sludge' (screw type heat exchanger) is mainly used for indirect sludge preheating at waste water treatment plants. Preheated sludge is pipelined into the digestion tanks, where anaerobic stabilisation is under way. A similar heat exchanger ''flue gas-sludge'' is being developed for the purpose of utilizing the available heat coming from sludge incineration. Principal advantages of this design are as follows: low energy consumption for sludge transport and easy access to the sludge side. The aim of this study is to describe the creation of a mathematical model of a heat exchanger, which will be used to monitor the influence of temperature on dewatering of mixed raw sludge. For this specific task a made-to-measure heat exchanger had to be designed. From the possible choices, a helical plate heat exchanger was chosen. The advantage of this type of an exchanger is a small built-up area, a high heat transfer area and easy maintenance and cleaning on the side of the sludge. Another advantage is a helical flow, which has a positive effect on self cleaning abilities. However, pressure losses would be higher than at direct (straight) canals. The increase of pressure loss is accompanied by an increased coefficient of heat exchange a. After the design of the exchanger measurements from a pilot unit would be obtained. On the base of them, the relations will be revised, if required. If sludge preheating shows to be advantageous for dewatering an exchanger of a ''fuel gas-sludge'' type would be designed in the next phase.
Keywords in Czech
výměník tepla, kal, ohřev
Keywords in English
heat exchanger, sludge, heating
RIV year
2006
Released
27.08.2006
Publisher
Process Engineering Publisher
Location
Praha
ISBN
80-86059-45-6
Book
Chisa 2006 - Summaries 4 - System engineering
Pages count
10
BIBTEX
@inproceedings{BUT24330,
author="Bohuslav {Kilkovský} and Jaroslav {Boráň} and Zbyněk {Straňák} and Lucie {Houdková} and Zdeněk {Jegla} and Petr {Stehlík},
title="Research and Development of Heat Exchanger 'Water-Sludge'",
booktitle="Chisa 2006 - Summaries 4 - System engineering",
year="2006",
month="August",
publisher="Process Engineering Publisher",
address="Praha",
isbn="80-86059-45-6"
}