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  • Conference paper
    Budinis S, Thornhill NF, 2014,

    An integrated control technique for compressor operation

    , United-Kingdom-Automatic-Control-Council (UKACC) 10th International Conference on Control (CONTROL), Publisher: IEEE, Pages: 444-449
  • Conference paper
    Xenos DP, Cicciotti M, Bouaswaig AEF, Thornhill NF, Martinez-Botas Ret al., 2014,


    , ASME Turbo Expo: Turbine Technical Conference and Exposition, Publisher: AMER SOC MECHANICAL ENGINEERS
  • Conference paper
    Xenos DP, Thornhill NF, Cicciotti M, Bouaswaig AEFet al., 2014,

    Preprocessing of Raw Data for Developing Steady-State Data-Driven Models for Optimizing Compressor Stations

    , United-Kingdom-Automatic-Control-Council (UKACC) 10th International Conference on Control (CONTROL), Publisher: IEEE, Pages: 438-443
  • Conference paper
    Cicciotti M, Xenos DP, Bouaswaig AEF, Thornhill NF, Martinez-Botas RFet al., 2014,


    , ASME Turbo Expo: Turbine Technical Conference and Exposition, Publisher: AMER SOC MECHANICAL ENGINEERS
  • Conference paper
    Mechleri ED, Thornhill NF, Biliyok C, 2014,

    Dynamic simulation and control of post-combustion CO capture with MEA in a gas fired power plant

    , 24th European Conference on Computer Aided Process Engineering (ESCAPE 24), Pages: 619-624, ISSN: 1570-7946

    This paper presents a dynamic model of a post combustion CO capture plant via chemical absorption using monoethanolamine (MEA) for natural gas combined cycle (NGCC) power plants. Insight regarding the process dynamics due to various disturbances caused by the operation of the power plant is presented and a control structure is proposed, based on heuristics. The performance of the proposed control scheme was evaluated by changing the flue gas flow rate which is commonly induced in the operation of power plants such as during start-up, shutdown and cyclic loading. Consideration has also been given to the variations to the control tuning due to the lower composition of CO in NGCC plant compared to coal fired power plants. The results have shown that with the implementation of the proposed control scheme, the flexible operation of the power plant in combination with the capture plant can be maintained. © 2014 Elsevier B.V.

  • Conference paper
    Cicciotti M, Bouaswaiga AEF, Martinez-Botas RF, Xenos DP, Thornhill NF, Manenti Fet al., 2014,

    Simultaneous Nonlinear Reconciliation and Update of Parameters for Online Use of First-Principles Models: An Industrial Case-Study on Compressors

    , 24th European Conference on Computer Aided Process Engineering (ESCAPE 24), Pages: 457-462, ISSN: 1570-7946

    Online uses of first-principles models include nonlinear model predictive control, softsensors, real-time optimization, and real-time process monitoring, among others. The industrial implementation of these applications needs accurate adaptive models and reconciled data. The simultaneous reconciliation and update of parameters of a first- principles model can be achieved using an optimization framework that exploits physical and analytical redundancy of information. This paper demonstrates this concept by means of an industrial case-study. The case-study is a multi-stage centrifugal compressor for which a first-principles model was recently developed. The update of the model parameters is necessary to capture slowly progressing mechanical degradation (e.g. due to fouling and erosion). The reconciliation of the data is necessary for reducing downtime of the online model-based applications caused by gross errors. Two industrial cases including sensor failures were analysed. Applying the proposed framework, it was possible to reconcile the measurements for both cases. © 2014 Elsevier B.V.

  • Conference paper
    Xenos DP, Kopanos GM, Pistikopoulos EN, Thornhill NF, Cicciotti Met al., 2014,

    Operational optimization of compressors in parallel considering condition-based maintenance

    , 24th European Conference on Computer Aided Process Engineering (ESCAPE 24), Pages: 1213-1218, ISSN: 1570-7946

    This paper suggests an optimization framework for the process and maintenance operations of a network of compressors. The health condition of a compressor varies during its operation due to mechanically degrading effects (e.g. fouling and corrosion) which results in decreasing performance and increasing power consumption. Currently, the industrial maintenance strategy considers preventive maintenance cycles, i.e. maximum running time of the compressors. Typically, the maintenance schedule of a compressor is examined separately without considering the interactions between the compressor and the overall process. In this work, the increase in the power consumption of each compressor is linearly correlated to the periods of continuous operation, and the results demonstrate that the simultaneous optimization of condition-based maintenance and operation reduces the overall costs. © 2014 Elsevier B.V.

  • Conference paper
    Romero DD, Graven T-G, Thornhill NF, 2014,

    Investigations on information-rich visualizations to explore process connectivity and causality

    , 24th European Conference on Computer Aided Process Engineering (ESCAPE 24), Pages: 811-816, ISSN: 1570-7946

    Complexity in large-scale chemical processes poses a challenge to engineers who need to understand causality and interconnectivity. Previous work has already taken advantage of the use of visualization for alarm correlation and plant-wide oscillation detection for small scale example processes, but the resulting correlation maps are limited in the number of variables that can be easily managed. This paper proposes a new approach to the visualization of connectivity information, which is capable of representing a large number of connections between process variables and units, as well as process-specific information and alarm history. The novel visualization is based on the Circos framework which is widely used for analysis of connectivity and causality in the field of genomics. The benefit of adapting information-rich visualizations for the field of process systems engineering will be discussed based on an academic use-case. © 2014 Elsevier B.V.

  • Conference paper
    Cecílio IM, Ersdal AM, Fabozzi D, Thornhill NFet al., 2013,

    An Open-Source Educational Toolbox for Power System Frequency Control Tuning and Optimization

    , 4th European Innovative Smart Grid Technologies (ISGT), Publisher: IEEE
  • Conference paper
    P Kunjumuhammed L, C Pal B, Anaparthi K, F Thornhill Net al., 2013,

    Effect of wind penetration on power system stability

  • Journal article
    Schleburg M, Christiansen L, Thornhill NF, Fay Aet al., 2013,

    A combined analysis of plant connectivity and alarm logs to reduce the number of alerts in an automation system

    , JOURNAL OF PROCESS CONTROL, Vol: 23, Pages: 839-851, ISSN: 0959-1524
  • Conference paper
    Fabozzi D, Thornhill NF, Pal BC, 2013,

    Frequency Restoration Reserve Control Scheme with Participation of Industrial Loads

    , Piscataway, NJ, IEEE PES PowerTech Grenoble 2013, Publisher: IEEE

    In order to accommodate larger amounts of renewable energy resources, whose power output is inherently unpredictable, there is an increasing need for frequency control power reserves. Loads are already used to provide replacement reserves, i.e. the slowest kind of reserves, in several power systems. This paper proposes a control scheme for frequency restoration reserves with participation of industrial loads. Frequency restoration reserves are required to change their active power within a time frame of tens of seconds to tens of minutes in response to a regulation signal. Industrial loads in many cases already have the capacity and capability to participate in this service. A mapping of their process constraints to power and energy demand is proposed in order to integrate industrial loads in existing control schemes. The proposed control scheme has been implemented in a 74-bus test system. Dynamic simulations show that industrial loads can be successfully integrated into the power system as frequency restoration reserves.

  • Conference paper
    P Kunjumuhammed L, C Pal B, F Thornhill N, 2013,

    A Test System Model for Stability Studies of UK Power Grid

    , IEEE PES PowerTech Grenoble 2013
  • Conference paper
    Yang Y, Farid SS, Thornhill NF, 2013,

    Decision tree for rapid prediction of bioprocess facility fit issues

    , 245th National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
  • Journal article
    Stonier A, Pain D, Westlake A, Hutchinson N, Thornhill NF, Farid SSet al., 2013,

    Integration of Stochastic Simulation with Multivariate Analysis: Short-Term Facility Fit Prediction

    , BIOTECHNOLOGY PROGRESS, Vol: 29, Pages: 368-377, ISSN: 8756-7938
  • Journal article
    Sharifzadeh M, Thornhill NF, 2013,

    Integrated design and control using a dynamic inversely controlled process model

    , COMPUTERS & CHEMICAL ENGINEERING, Vol: 48, Pages: 121-134, ISSN: 0098-1354
  • Conference paper
    Yang Y, Farid SS, Thornhill NF, 2013,

    Prediction of biopharmaceutical facility fit issues using decision tree analysis

    , 23rd European Symposium on Computer Aided Process Engineering (ESCAPE), Publisher: ELSEVIER SCIENCE BV, Pages: 61-66, ISSN: 1570-7946
  • Conference paper
    Sorensen E, Thornhill NF, Akinmolayan F, 2013,

    Predictive modelling of a conventional clean water treatment work

  • Conference paper
    Budinis S, Fabozzi D, Thornhill NF, 2013,

    A control technique based on compressor characteristics with applications to carbon capture and storage systems

    Introduction: Compressors are vital pieces of equipment within the process industry and they are going to be important in the next few years for dealing with carbon dioxide from carbon capture and storage (CCS) systems. Compressor characteristics (also called compressor maps) represent the operation of the machine in a graphical form. They are provided by the manufacturer of the compressor together with the machine and they are generated via experiments at reference conditions. The most common compressor characteristics represent the pressure ratio of the machine (i.e. the ratio between the output pressure and the input pressure) as a function of inlet flowrate and rotational shaft speed. For a single speed machine there is a single characteristic curve rather than a map (where instead the same function is plotted more times for different shaft speeds). While the inlet flowrate of the machine is generally a boundary condition of the compression system, the rotational shaft speed is very often the manipulated variable of the control system for a variable speed compressor. State of the art and open questions: Steady state and dynamic simulations are routinely used by academics and practitioners to represent and analyse the behaviour of a compressor during different activities such as design, control and optimization of the machine. In the literature there are many examples of compressor dynamic models (Botros et al., 1991, Venturini, 2005, Camporeale et al., 2006). Different techniques have been proposed for simulation and control applications. However the models found in the literature do not rely much on the compressor characteristics. The reason for that is that they usually represent simple compressors i.e. single stage lab-size machine that can be tested in a lab to provide the parameters needed for the model calibration. This type of machine is closer to an ideal compressor than an industrial compressor. For this reason a simplified model cannot capture accurate

  • Conference paper
    Cicciotti M, Geist S, Schild A, Martinez-Botas RF, Romagnoli A, Thornhill NFet al., 2013,

    Systematic one zone meanline modelling of centrifugal compressors for industrial online applications

    , ASME Turbo Expo 2013, San Antonio, Texas, June 3-7 2013, paper GT2013/95821

    For developing model-based online applications such as condition monitoring and condition-based maintenance or real-time optimization, highly representative and yet simple physical models of centrifugal compressors are necessary. Previous investigations have shown that in this context meanline models represent a valid alternative to the commonly used empirical based modelling methodologies such as polynomial regression models or artificial neural networks. This paper provides a methodology for tailoring meanline models to multistage centrifugal compressors by appropriate selection and adaptation of loss correlations. Guidelines for the selection of the boundary conditions are also provided. The potential of the methodology is demonstrated in the Proof-of-concept section using two sets of data obtained from an air multistage centrifugal compressor operated in BASF SE, Ludwigshafen, Germany. The first set of data was used to calibrate the model whereas the second one was used for validation. The model results show that the predictions of stagnation temperature and pressure at the outlet of the stage deviate from the measurements respectively 0.15-3% and of 0.66-1.1% respectively. The results are discussed in the current paper. Copyright © 2013 by ASME.

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