Combustion of Apple Juice Wastes in a Cyclone Combustor for Thermal Energy Generation

Author(s):  
Elaine Virmond ◽  
Robson L. Schacker ◽  
Waldir Albrecht ◽  
Christine A. Althoff ◽  
Mauri´cio de Souza ◽  
...  

The thermal conversion of biomass fuels using different combustion technologies has increased worldwidely in the latest years due to the energetic exploitation potential of wastes as well as to the strong increase of environmental consciousness in the industrial sector. In this work the bagasse obtained from the apple juice industry (AB) was characterized and the gaseous emissions resulting from its combustion in a pilot scale cyclone combustor were measured and compared to limits imposed by Brazilian and international current legislations. Wood and wood-based materials are extensively used as fuel for thermal energy generation particularly in the Brazilian food industry, which demands large amounts of steam. Considering that, sawdust (SD) was also characterized, burned in the same conditions and the gaseous emissions analyzed for comparison purposes. Sampling for the volatile organic compounds benzene, toluene, ethyl-benzene and xylene (BTEX, expressed as total organic carbon, TOC) and polycyclic aromatic hydrocarbons (PAH) were performed and the samples analyzed by gaseous chromatography-mass spectrometry (GC-MS). Chemical properties showed that the volatile matter value of AB is high (85.36 wt%, daf) what indicates that the solid burn rapidly. The absence of sulfur in its composition represents an advantage in relation to fossil fuels because its combustion does not release sulfur derived compounds. The lower heating value is 21.09 MJ.kg−1 (daf), 26.9% higher than the heating value of SD (16.62 MJ.kg−1). The effect of the N fuel content found in AB composition was clearly noticed through the high NOx concentration in the flue gas resulted from its burning. Comparing the properties and the burning profiles of SD and AB, it can be stated that this industrial waste obtained from the apple juice industry is suitable for direct combustion, constituting a renewable energy source for this industrial sector, however, measures as air staging and staged addition of fuel, or flue gas cleaning technologies would be required for reducing the NOx emission. Concerning the presence of toxic compounds as PAH, they were not detected once the operation conditions applied resulted in controlled gaseous emissions and temperature profile. Also, TOC concentrations remained below the regulations limits considered.

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Elaine Virmond ◽  
Robson L. Schacker ◽  
Waldir Albrecht ◽  
Christine A. Althoff ◽  
Maurício de Souza ◽  
...  

The solid waste generated from the apple juice industry (apple bagasse (AB)) was characterized as a fuel, and the potential for its utilization as an alternative energy source was assessed through its combustion in a pilot scale cyclone combustor. A comparative evaluation of the AB and sawdust (SD) properties, as well as of the emissions during the combustion tests, was performed. The high energy content of AB (lower heating value (LHV) equal to 21.09 MJ kg−1), dry and ash-free (daf) basis, which is 26.9% higher than the LHV of SD (16.62 MJ kg−1, daf), and combined with the high volatile matter content (85.36 wt %, daf) improve the ignition and burning of the solids. The emissions of CO, SO2, and NOx and the total organic carbon (TOC) were compared with guideline limits established by Brazilian and international legislation. AB generated much lower CO than sawdust in spite of almost half of excess air levels (13% compared with 26%) and met even the stringent limit of the German regulation for waste incineration. The unburned carbon percentages found in the ash resulted from SD and AB combustion tests were 0.24% and 0.96% in weight, respectively. The absence of sulfur in AB composition represents an advantage with nondetectable SO2. The average level of NOx emission with SD combustion was 242 mg N m−3 and met all the regulation limits. The average NOx emission with AB combustion though was 642 mg N m−3 and met the U.S. EPA regulation but was marginally higher than the Brazilian norm by 15%. TOC concentrations remained below the limits considered even though the TOC level was higher in the AB combustion test. Polycyclic aromatic hydrocarbons (PAH) were not detected or were under the quantification limit of the equipment used in their analysis. Comparing the properties, the burning profiles of SD and AB, and the emissions from their combustion tests, it can be stated that the waste originating from the apple juice industry is suitable for direct combustion, constituting a renewable energy source for this industrial sector.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2950 ◽  
Author(s):  
Isidoro Lillo-Bravo ◽  
Elena Pérez-Aparicio ◽  
Natividad Sancho-Caparrini ◽  
Manuel Silva-Pérez

This paper analyses the possible applications of medium temperature solar concentration technologies, Compound Parabolic Collector, Linear Fresnel Collector and Parabolic Trough Collector in the Spanish industrial sector. Results of this study allow evaluating whether or not solar technologies are an alternative to conventional sources. This possibility is analyzed energetically, economically and environmentally. Results show that the percentage of solar use is decisive in determining the true thermal energy generation cost. The other essential parameter is the solar field area due to produce economy of scale that reduces investment costs. Fluid temperature has significant influence mainly in Compound Parabolic Collector technology. Results obtained in this paper collect multiple alternatives and allow comparing for different scenarios the suitability to replace conventional energy sources by thermal energy obtained from medium temperature solar concentration technologies from an economic perspective. For instance, for percentage of solar use equal to 100%, the lowest thermal energy generation costs for each technology are 1.3 c€/kWh for Compound Parabolic Collector technology, fluid temperature of 100 °C and industrial process located in Seville, 2.4 c€/kWh for Linear Fresnel Collector technology, fluid temperature of 170 °C and industrial process located in Jaen, 3.3 c€/kWh for technology, fluid temperature of 350 °C and industrial process located in Jaen. These costs are lower than conventional energy sources costs.


Author(s):  
Sagnik Pal ◽  
Ranjan Das

The present paper introduces an accurate numerical procedure to assess the internal thermal energy generation in an annular porous-finned heat sink from the sole assessment of surface temperature profile using the golden section search technique. All possible heat transfer modes and temperature dependence of all thermal parameters are accounted for in the present nonlinear model. At first, the direct problem is numerically solved using the Runge–Kutta method, whereas for predicting the prevailing heat generation within a given generalized fin domain an inverse method is used with the aid of the golden section search technique. After simplifications, the proposed scheme is credibly verified with other methodologies reported in the existing literature. Numerical predictions are performed under different levels of Gaussian noise from which accurate reconstructions are observed for measurement error up to 20%. The sensitivity study deciphers that the surface temperature field in itself is a strong function of the surface porosity, and the same is controlled through a joint trade-off among heat generation and other thermo-geometrical parameters. The present results acquired from the golden section search technique-assisted inverse method are proposed to be suitable for designing effective and robust porous fin heat sinks in order to deliver safe and enhanced heat transfer along with significant weight reduction with respect to the conventionally used systems. The present inverse estimation technique is proposed to be robust as it can be easily tailored to analyse all possible geometries manufactured from any material in a more accurate manner by taking into account all feasible heat transfer modes.


Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 120
Author(s):  
Francisco Fernández ◽  
José Díaz ◽  
María Folgueras ◽  
Inés Suárez

Thermal energy storage systems help to couple thermal energy generation and process demand in cogeneration facilities. One single deposit with two design temperatures and one main temperature step in sensible thermal energy storage define the thermocline systems. Performance of one high size real thermocline thermal energy storage system is analysed. Starting from temperature and mass flow rate data registered by the plant control system, one advanced thermodynamic analysis is performed. The quality of heat storage is analysed in terms of evaluation of the stratification in the thermocline zone. The temperature data registered at 21 positions is extended by displacement analysis generating detailed profiles. Fraction of recoverable heat, thermocline width, stratification indices based on energy and exergy analysis, and mean temperature gradients in the thermocline region are calculated. These parameters are monitored under real operation conditions of the plant. The calculated parameters are studied to check their distribution and correlation. First and Second Law indices show parallel behaviour and two values are found that delimit situations of high and low values of mean temperature gradients. It was observed that buoyancy generates uniform forced movement with the right water temperature entering the diffusers, but good control strategies are essential to avoid mixing. The system demonstrated great stability in this use.


2017 ◽  
Vol 41 (6) ◽  
Author(s):  
Marcos Antonio da Silva Miranda ◽  
Gabriel Browne de Deus Ribeiro ◽  
Sebastião Renato Valverde ◽  
Crismeire Isbaex

ABSTRACT The main objective of this work was to identify and analyze the potential of forest biomass of Eucalyptus sp. such as thermal energy source for industrial use in place of fossil fuels. Two cases were analyzed: the first one estimated the total demand for forest biomass to replace the main fossil fuels in Brazilian industrial sector, with scenarios of 100, 75 and 50% replacement; in the second, it was calculated the cost of each fuel for producing ton of industrial steam (thermal energy) for a dairy industry, in order to verify the competitiveness of forest biomass compared to fossil fuels. The results showed that the areas demanded to replace 100, 75 and 50% of the analyzed fossil fuels were, respectively, 2.9, 2.2 and 1.5 million planted forests hectares, and the steam ton cost ratio using the woodchips was at least 34% lower than with other fuels, which corroborates the substitution potential in this sector.


Author(s):  
M. E. Douglas ◽  
Timothy C. Wagner ◽  
Michael K. Sahm ◽  
William J. Wepfer

The determination of a prime mover’s characteristics is important in ascertaining its suitability for combined heat and power (CHP) applications. By definition, its operation affects the operation of all heat recovery equipment downstream. The correct balance between component electrical efficiency and waste heat is needed if the electric power producing equipment is to be used in a CHP application in a cost effective manner. Understanding the relationship between electric efficiency and exhaust stream energy content for different prime movers systems is a first step in an overall CHP system optimization. The goals of this work are to determine the potential financial benefit of utilizing waste heat from various prime mover configurations as well as establish the relationship between the two types of energy generation and costs. An economic optimization was performed to determine the system with the lowest average product (electricity and thermal energy) generation cost. The prime mover system was required to meet the electrical load demand of a typical 9290 m2 (100,000 ft2) office building in New York, NY, USA. The composition of the most cost effective prime mover system, when considering both electrical and thermal energy generation, was shown to be a single microturbine. When comparing the electrical and thermal energy generation of all systems studied with product generation cost, the more cost effective systems had either high electrical efficiency with a low thermal energy generation or high amounts of waste heat with low electrical efficiency. Each installation site and load demand is unique. The results of this study, along with others, can be used to help determine a cost effective system for a particular application.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5107 ◽  
Author(s):  
Magdalena Dołżyńska ◽  
Sławomir Obidziński ◽  
Jolanta Piekut ◽  
Güray Yildiz

Agri-food waste is generated at various food cycle stages and is considered to be a valuable feedstock in energy systems and chemical syntheses. This research identifies the potential and suitability of a representative agri-food waste sample (i.e., plum stones) as a solid fuel. Ground plum stones containing 10, 15, and 20 wt.% of rye bran were subjected to pelletization. The pelletizer was operated at 170, 220, and 270 rpm, and its power demand for the mixture containing 20 wt.% of rye bran was 1.81, 1.89, and 2.21 kW, respectively. Such pellets had the highest quality in terms of their density (814.6 kg·m−3), kinetic durability (87.8%), lower heating value (20.04 MJ·kg−1), and elemental composition (C: 54.1 wt.%; H: 6.4 wt.%; N: 0.73 wt.%; S: 0.103 wt.%; Cl: 0.002 wt.%; O: 38.2 wt.%). Whole plum stones and pellets were subjected to combustion in a 25 kW retort grate boiler in order to determine the changes in the concentrations of NO, SO2, CO, CO2, HCl, and O2 in the post-combustion flue gas. Collected results indicate that plum stone–rye bran pellets can serve as effective substitutes for wood pellets in prosumer installations, meeting the Ecodesign Directive requirements for CO and NO.


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