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Bujak J.W.,Polish Association of Sanitary Engineers
Energy | Year: 2015

Highly efficient utilization of the energy potential of waste is a crucial matter in the process of thermal conversion. A vast majority of research studies published to this date on electrical energy and heat recovery have been concerned with large MSW (municipal solid waste) incineration systems. Only few of the publications presented the research on electrical energy and heat recovery in small and medium incinerating plants. They were focused on the production of syngas (waste gasification) and its combustion in gas engines. The research studies described in the article included electrical energy and heat recovery from the medical waste incineration installation with the efficiency of 220 kg/h. The research was carried out in a large hospital facility. The tested installation consisted of three basic elements: HSRG (heat recovery steam generator), MT (microturbine) producing electrical energy and steam/water heat exchanger. The efficiency values of individual units were high: HRSG-78%, MT-79% and HT-99%. The total disposable enthalpy flux of steam entering the turbine was low and it was not possible to produce a sufficient amount of electricity. The average electrical energy flux produced during the tests amounted to E˙ue-MT = 31.6 kWe, which constituted 4.2% of the total flux of usable energy recovered by the installation. The rest was the enthalpy flux of hot water - E˙ue-HE = 729 kW (95.8%). Such installations can be used, provided that there are systems that are capable of receiving that type of heat throughout the entire calendar year. It was proven that the experimental installation had small impact on the environment. The SPB (simple payback period) of the investment expenditures incurred in order to complete the installation amounted to 3.1 years. © 2015 Elsevier Ltd.

Bujak J.,Polish Association of Sanitary Engineers
Waste Management | Year: 2015

The article presents a mathematical model to determine the flux of incinerated waste in terms of its calorific values. The model is applicable in waste incineration systems equipped with rotary kilns. It is based on the known and proven energy flux balances and equations that describe the specific losses of energy flux while considering the specificity of waste incineration systems. The model is universal as it can be used both for the analysis and testing of systems burning different types of waste (municipal, medical, animal, etc.) and for allowing the use of any kind of additional fuel. Types of waste incinerated and additional fuel are identified by a determination of their elemental composition. The computational model has been verified in three existing industrial-scale plants. Each system incinerated a different type of waste. Each waste type was selected in terms of a different calorific value. This allowed the full verification of the model. Therefore the model can be used to optimize the operation of waste incineration system both at the design stage and during its lifetime. © 2015 Elsevier Ltd.

Malinowski P.,Wroclaw University of Technology | Sulowicz M.,Cracow University of Technology | Bujak J.,Polish Association of Sanitary Engineers
International Journal of Refrigeration | Year: 2011

This article presents the application of a neural model of heat transfer for the purpose of forecasting temperature at selected points of a circulating water ring network. The purpose of a circulating water system is to lower the temperature of petroleum products manufactured on numerous petrochemical lines at a Polish petrochemical plant. Temperature forecasting at 96 nodes of the circulating water system, significant from the point of view of system operation, is carried out using SVM neural networks. Neural networks learn based on archival data recorded in the process parameter monitoring system. Thermal, hydraulic and control parameters of the cooling process, as well as weather variables, constitute crucial input data for the neural model. The temperature forecasting algorithm has been implemented in a computer program that was then applied and remains in use for temperature forecasting in a maintenance department of an industrial plant. © 2010 Elsevier Ltd and IIR. All rights reserved.

Bujak J.W.,Polish Association of Sanitary Engineers
Renewable Energy | Year: 2015

This paper discusses the effects of changes in the management methods for animal by-products in a meat-processing plant after the implementation of an onsite thermal process waste recycling system and the construction of a production facility for mineral fertilisers. The changes concern cured meat production at a beef, pork and poultry cutting plant with a capacity of 150 tons per day. The remains of the processing comprise 17 tons per day of bones and pulp from meat and bone, which are burnt to ash. The resulting waste (ash) is converted into a new and useful product: mineral fertiliser. This paper details a case study of the first facility in Poland with an animal by-product thermal recycling facility and a plant, located at the meat-processing factory, that produces mineral fertiliser for agriculture and horticulture. The results of this study indicate that the management of animal by-products eliminates some of the negative effects related to their transport to local facilities for disposal. The study also highlights substantial ecological, energy-related and economic advantages. © 2015 Elsevier Ltd.

Bujak J.,Polish Association of Sanitary Engineers
Polish Journal of Environmental Studies | Year: 2010

This paper presents an experimental study of the heating value of medical waste using an input-output method. The study was carried out at the Oncological Hospital in Bydgoszcz, Poland, over a period of three months. The installation for thermal treatment consisted of a loading unit, a combustion chamber, and a discharge chamber (thermoreactor). The medical waste constituted the primary fuel, and high-methane natural gas acted as the secondary fuel. With regard to the high heating value and low humidity of medical waste, the thermal processing in the combustion chamber fulfilled the criterion of stable combustion (autothcrmal combustion). The average temperature in the combustion chamber was 665.5°C during the testing period. The study showed that the heating value of the waste varied considerably. The amount of incinerated waste varied between mmw=70 kg/h and 140 kg/h during the testing period. The calorific value of the medical waste fluctuated between 8.5 MJ/kg and 41.2 MJ/kg, with a mean value of qmw=19.1 MJ/kg.

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