Time filter

Source Type

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.,Polish Association of Sanitary Engineers | Sitarz P.,PPM PROMONT Bujak Sp. z o.o. Sp. K.
Waste Management | Year: 2016

This paper presents model analyses and tests of animal by-product waste thermal treatment plants. A schedule of tests was prepared, and 62,024 cases of system operation were analysed. A map/work field of the tested plant was drawn up on the basis thereof. Calculations were made following an algorithm described by Bujak (2015a) written in the VBA (Visual Basic for Application) language. The tests showed that when incinerating animal waste, the flux of physical enthalpy of the flue gas from the afterburner chamber depends on numerous design and operating parameters. The most important include the following: humidity and flux of the waste, concentration of oxygen in the flue gas in the afterburner chamber and loss of heat flux to the atmosphere through the external surfaces of the plant. Individual design and operating parameters can be selected so that the process of incineration is ensured without additional fuel. The performed analyses were verified against the actual object at the industrial scale using a meat plant that manufactures ham and processes beef, pork and poultry with a capacity of 150. tonnes/day. The production process waste included mainly bones and - in much smaller quantities - meat and bone meal, at 17. tonnes/day. The performed tests and analyses can be used to optimise the operation of the waste thermal treatment plant at the stages of design and operation. © 2016 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.


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

This paper presents the results of a pilot study of a thermal utilization installation for incinerating plastic waste. The research was conducted on an industrial scale in a plant that manufactures plastic tape (used for warning, packing and masking purposes, among others). The system was considered in terms of three aspects: energy, environmental and economic. Due to the very high LCV (lower calorific value) of the waste, an innovative rotary combustion chamber (rotary kiln) was employed. The experimental installation was analysed in terms of the temperature distribution in the rotary kiln, secondary combustion (afterburner) chamber and heat recovery system. The thermal efficiency of the tested installation was determined. The emissions into the atmosphere were measured and compared with the applicable emission standards. Due to the nature of the waste, particular attention was paid to emission analysis of carbon oxide and volatile organic compounds. In terms of the economic aspect, fundamental economic indicators were found for the tested system to determine the profitability of its construction. © 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.


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

Experimental studies were performed on two saturated steam heat recovery systems, referred to as HRSGs. Heat recovery systems are one element of a thermal treatment (incineration) system for medical waste. The two HRSG systems were equipped with assemblies for cleaning the primary heat exchange surface on the flue gas side. The HRSG systems were analysed for energy and economy. The following factors were measured: flue gas temperature at the input and output, useful energy flux, thermal efficiency and the impact of volatile pollutants in the flue gas on the operation. The most effective system for removing contaminants from the surface of the flue gas was determined. The adopted design was compared to the construction of the HRSG systems using real parameters recorded during operation. The financial benefits, resulting from shorter stoppage times achieved through the use of an efficient cleaning system were calculated. © 2015 Elsevier Ltd.


Bujak J.,Polish Association of Sanitary Engineers
Energy and Buildings | Year: 2010

This study analyses heat consumption for heating domestic water in large hospital facilities with over 600 hospital beds. The tests were carried out in 2 hospitals: the 715-bed University Hospital in Bydgoszcz and the 690-bed Provincial Hospital. The tests were performed over a period of 4 years: 2005-2008 for the first hospital and 2003-2006 for the second. The aim of this study is to analyse the variations and seasonal changes in the heat consumed to produce domestic hot water during the specified time periods. The results of this study show the yearly, monthly, daily, and hourly consumption of heat for domestic hot water. Particular emphasis is placed on the daily and hourly heat-consumption irregularity coefficients for domestic hot water. The results of this study may be used, for example, to predict heat consumption when designing new hospital facilities with 500-800 beds, to determine the heating power of the heat source and individual centres. Data on the constant and low-temperature heat consumption for domestic hot water throughout the whole year are particularly useful, as these data may be used to analyse existing large hospitals that are seeking alternative solutions (such as renewable energy or energy recycling) to reduce fossil fuel consumption. © 2010 Elsevier B.V. All rights reserved.


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

This paper presents the results of a study of an experimental system with thermal treatment (incineration) of medical waste conducted at a large complex of hospital facilities. The studies were conducted for a period of one month. The processing system was analysed in terms of the energy, environmental and economic aspects. A rotary combustion chamber was designed and built with the strictly assumed length to inner diameter ratio of 4:1. In terms of energy, the temperature distribution was tested in the rotary kiln, secondary combustion (afterburner) chamber and heat recovery system. Calorific value of medical waste was 25.0MJ/kg and the thermal efficiency of the entire system equalled 66.8%. Next, measurements of the pollutant emissions into the atmosphere were performed. Due to the nature of the disposed waste, particular attention was paid to the one-minute average values of carbon oxide and volatile organic compounds as well as hydrochloride, hydrogen fluoride, sulphur dioxide and total dust. Maximum content of non-oxidized organic compounds in slag and bottom ash were also verified during the analyses. The best rotary speed for the combustion chamber was selected to obtain proper afterburning of the bottom slag. Total organic carbon content was 2.9%. The test results were used to determine the basic economic indicators of the test system for evaluating the profitability of its construction. Simple payback time (SPB) for capital expenditures on the implementation of the project was 4 years. © 2015 Elsevier Ltd.

Loading Polish Association of Sanitary Engineers collaborators
Loading Polish Association of Sanitary Engineers collaborators