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    Novel Strategies for Cleaning-in-Place Operations

    Yang, Jifeng

    Publication date: 2018

    Document Version Publisher's PDF, also known as Version of record

    Link back to DTU Orbit

    Citation (APA): Yang, J. (2018). Novel Strategies for Cleaning-in-Place Operations. Technical University of Denmark.

  • DTU Chemical Engineering Department of Chemical and Biochemical Engineering

    Novel Strategies for Cleaning-in-Place Operations Jifeng Yang PhD thesis November 2018

  • Novel Strategies for Cleaning-in-Place Operations

    Ph.D. Thesis

    Jifeng Yang


    Ulrich Krühne (DTU) Krist V. Gernaey (DTU)

    Mikkel Nordkvist (Alfa Laval)

    Department of Chemical and Biochemical Engineering Technical University of Denmark

    2800 Kgs. Lyngby Denmark

    November, 2018

  • Copyright©: Søren Heintz




    September 2015

    Process and Systems Engineering Center (PROSYS)

    Department of Chemical and Biochemical Engineering

    Technical University of Denmark

    Building 229

    Dk-2800 Kgs. Lyngby


    +45 4525 2800

    Print: STEP

    Jifeng Yang

    November 2018

    Copyright 2018 Jifeng Yang All rights reserved.


  • Summary Cleaning-in-place (CIP) is a widely used technique in food and pharmaceutical industries. The execution of CIP is critical for food safety and public health. Since the introduction of CIP, various studies have been performed in order to reduce the cleaning costs without compromising the cleaning quality.

    The starting point for this thesis was a mapping study at the world-leading brewery, Carlsberg Danmark A/S (Fredericia), in which the most time- and resource-consuming CIP operations were identified. The suggestions for improving the existing CIP systems in the brewery are representative for the processes where similar CIP systems are utilized in other fields. The findings from the mapping study led to the topics explored in this Ph.D study.

    The objective of this thesis is to investigate different approaches for reducing the resource consumption and cleaning costs during CIP operations. A number of parallel projects were defined and conducted for this purpose. All of these projects can stand alone when reading this thesis.

    Firstly, a study based on the cleaning of an industrial brewery fermenter demonstrates how to analyse historical cleaning data to improve cleaning operations in the future. The proposed analysis approach detects anomalies in a CIP system online and offline. A trouble-shooting process is advised to guide the operators to diagnose the likely anomaly or fault.

    Secondly, Computational Fluid Dynamics (CFD) was used to simulate the displacement of cleaning agent by water during the intermediate and final rinses of pipe systems. The results obtained include the identification of dead zones and the calculation of rinsing time, minimum water consumption, minimum generation of waste water, and pressure drop, etc. The cross-comparison of different pipe geometries indicates the key factors that determine the cleanability of various pipe elements. CFD proves to be an effective tool for the hygienic design of pipe systems and the optimization of pipe rinsing.

    Thirdly, burst cleaning technique to clean the tank surfaces soiled by egg yolk was studied. The experimental observations were compared with the conventional cleaning method using continuous flows. Different cleaning parameters were investigated and optimised for removing the soil material at the lowest cleaning costs. The primary findings from pilot-scale studies were then examined in scale-up tests.

    Fourthly, a three-stage measurement-based partial recovery CIP system was designed.

  • ii Summary

    The purpose of the design was to prolong the lifetime of cleaning liquid by only recycling the clear liquid from the CIP outlet. The proposed approach was compared with other cleaning scenarios for economic analysis.

    Lastly, the cleaning of toothpaste soil from vessel surfaces by impinging liquid jet and falling film was studied. The properties of the soil material and the removal force were investigated. The adhesive removal model presented by other researchers was applied to describe the experimental results. This study is the first work to integrate the effect of soil soaking and the cleaning by falling film into the existing model.

  • Dansk Resume Cleaning-in-place (CIP) er en udbredt teknik inden for fødevare- og farmaceutiske in- dustrier. Gennemførelsen af CIP er meget vigtig for fødevaresikkerhed og folkesundhed. Siden introduktionen af CIP er der blevet foretaget en række undersøgelser for at reducere rengøringsomkostningerne uden at gå på kompromis med rengøringskvaliteten.

    Udgangspunktet for denne ph.d.-afhandling var en kortlægningsundersøgelse på det ver- densledende bryggeri, Carlsberg Danmark A/S (Fredericia), i hvilket de mest tidskrævende og ressourcekrævende trin i CIP-operationer blev identificeret. Forslagene til forbedring af de eksisterende CIP-systemer i bryggeriet kan overføres til processer, hvor lignende CIP-systemer bruges på andre områder. Resultaterne fra kortlægningsundersøgelsen af- fødte emnerne for dette ph.d.-studie.

    Formålet med denne afhandling er at undersøge forskellige metoder til at reducere ressource- forbrug og rengøringsomkostninger under CIP-operationer. En række parallelle projekter blev defineret for at møde dette formål. Alle disse projekter kan stå alene, når man læser denne afhandling.

    Først viser et studie baseret på rengøringen af en industriel bryggerifermenter hvordan man kan analysere historiske rengøringsdata for at forbedre rengøringsprocesserne i fremti- den. Den foreslåede analysemetode gør det muligt at detektere anomalier i et CIP-system, både online og offline. En fejlfindingsproces anbefales for at guide operatørerne til at di- agnosticere sandsynlige anomali eller fejl.

    I anden del af afhandlingen bruges Computational Fluid Dynamics (CFD) til at simulere fjernelsen af rengøringsmiddel med vand under mellemliggende og slutskyl af et rørsystem. De opnåede resultater omfatter identifikation af ‘døde’ zoner og beregning af rensningstid, mindste vandforbrug, mindste generening af spildevand og trykfald etc. Sammenligningen af forskellige rørgeometrier indikerer de nøglefaktorer, der bestemmer rengøringsvenlighe- den af forskellige rørelementer. CFD viser sig at være en effektiv metode til hygiejnisk design af rørsystemer og optimering af rørrensning.

    I tredje del studeres en ‘burst’ rengøringsteknik til rengøring af tankoverflader, der er tilsmudset af æggeblomme. De eksperimentelle resultater sammenlignes med den konven- tionelle rengøringsmetode, hvor der bruges kontinuerligt flow. Forskellige rengøringsparame- tre undersøges og optimeres til fjernelse af smudsmaterialet til de laveste rengøring- somkostninger. De primære resultater fra pilotskalaundersøgelser undersøges herefter i opskaleringstest.

    I fjerde del designes et tretrins målebaseret partielt genvinding CIP system. Formålet

  • iv Dansk Resume

    med designet er at forlænge rengøringsvæskens levetid ved kun at genbruge den klare væske fra CIP udløbsstrøm. Den foreslåede tilgang sammenlignes med andre rengøring scenarier i en økonomisk analyse.

    Endelig studeres rensningen af tandpasta fra tankoverflader med jet-væskestråler og faldende film. Besmudsningsmaterialets egenskaber og fjernelseskraften undersøges. Den klæbende fjernelses-model fremlagt af andre forskere anvendes til at beskrive de eksperi- mentelle resultater. Denne undersøgelse er det første eksperimentle studie, der integrerer effekten af jordopblødning og rensning med faldende film i den eksisterende model.

  • Preface This thesis is prepared at the department of Chemical and Biochemical Engineering at the Technical University of Denmark (DTU) in fulfilment of the requirements for acquiring a Ph.D degree. The project was carried out from December 2015 to November 2018, in cooperation with Alfa Laval Copenhagen A/S.

    I would like to express my heartfelt gratitude to my academic supervisors Ulrich Krühne and Krist V. Gernaey from DTU, and my industrial supervisor Mikkel Nordkvist from Alfa Laval. All of them have devoted lots of time and efforts to my work. I keep their untiring and sincere teachings in my mind. It has been a great pleasure to work together and witness my research progress.

    I would also like to th


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