This thesis deals with reducing the moisture content of biomass drying and its subsequent use as biofuel. The work is a belt drying and its integration into the system with a grate boiler. It proposes a variety of drying options for use of different drying media. In the end, an economic evaluation of the combustion system uses a belt dryer, and a system without any possibility of drying the fuel before it enters the boiler.

The aim of this work is to create a computational model of radial industrial tumble dryers, to calculate and identify the amount of air that flows through the inside of the drum itself. The calculation will be performed via computational fluid dynamics (CFD). Furthermore, compile transient balance model of mentioned dryers. Perform simulation balance model and compare the results of simulations with experimental measurements. By comparing the experimental data and simulation to determine the degrees of freedom of balance model and evaluate their impact on the assembled transient model. For a better understanding of the drying process, there is constructed a system of differential equations describing heat and moisture within the material being dried on a simple model. In the section devoted to the computational analysis of fluid flow is analyzed existing geometry of the drum, which has a major impact on the flow of air inside the drum itself. Following describes how to simplify its complex geometry entering the computational fluid dynamics. Then, there is carried out a simulation of fluid flow inside the tumble dryers using MRF and Sliding Mesh models. Finally, there is an analysis of the data obtained and determined the average amount of air flowing through the drum itself. On the contrary, the aim of the work is not to create another text tool for students engaged in CFD theme.

The degree project was done at Södra Cell Värö with the purpose to investigate how the use of energy for pulp drying in a pulp dryer could be made more effective to decrease the energy consumption or increase the capacity. The pulp dryer is one of the machines that consumes the most energy at SCV. The air that dryes the pulp is heated by low pressure steam, and since the amount low pressure steam was limited, the purpose with the project was to investigate how the low pressure steam best could be used. If the drying capacity could be improved it could enable for an increase in production or a decrease low pressure steam consumption. The task was divided into: 1. Analysis of steam and condensate flows connected to the pulp dryer. Can they be adjusted to improve the drying capacity? 2. Investigation of possible sectors of application for hot air flows from vacuum pumps. 3. Investigation of the condensate system. Can condensate and flash steam be used in a better way to provide more steam to the pulp dryer? For task 1, air and energy balances were made ove the pulp dryer, then temperature, flow and moisture content were measured for all air flows in and out. To investigate how the consumption low pressure steam in the pulp dryer depends on the air flows in to the pulp dryer, tests were made where the rotation speed for the fans and the temperature for the air were varied. The result of measuring the air balance over the pulp dryer was that the same amount air was going in and out, which means that all the air was going in to the dryer preheated. The energy balance over the thermal recycling system showed that 40 % of the energy in outgoing air was being reused. Increasing the rotation speed from 750 rpm to 1000 rpm was favourable when the production was high. Increasing the temperature of the air in to the pulp dryer showed that the consumption low pressure steam decreased. Recommended rotation speeds: December – february: 1000 rpm, all levels of production mars – november: 1000 rpm for high production (over 3 bar low pressure steam to pulp dryer) 750 rpm for low production (below 3 bar low pressure steam to pulp dryer) For task 2, temperature, flow and moisture content were measured for all air flows out from the vacuum pumps. The air flows out from the vacuum pumps had a temperature of 40-50 °C, which was too low to be used for preheating of air to pulp dryer. For task 3, a mapping of the condensate system including all steam and condensate flows connected to the pulp dryer was made. The mapping was made in AutoCAD. Since the experiment with increased temperature of the air in to the pulp dryer showed that an increase in temperature caused the consumption low pressure steam to decrease, calculations of how much more the consumption low pressure steam could be decreased by switching to steam of a higher pressure for preaheating the drying air. By using only steam of higher pressure for air preheating, the amount available low pressure steam to the pulp dryer could be increased with 6 tonnes/h. / Examensarbetet utfördes på Södra Cell Värö med syfte att undersöka hur energianvändningen för massatorkning på torkmaskinen (TM) kunde effektiviseras för att ge lägre energiförbrukning eller högre kapacitet. TM är en av de mest energiförbrukande avdelningarna på bruket. Massan torkas där med luft som värms av processånga vilken utgörs av lågtrycksånga, och eftersom tillgången av lågtrycksånga var begränsad var det önskvärt att undersöka hur den kunde användas på mest effektiva sätt. Om torkkapaciteten kan förbättras kan det möjliggöra en ökning av produktionen alternativt en minskning av förbrukning av lågtrycksånga. Uppgiften delades upp i: 1. Analys av ång- och luftflöden kopplat till TM. Kan de justeras för att ge bättre torkkapacitet? 2. Undersökning av möjliga användningsområden för varma luftflöden från vakuumpumparna. 3. Undersökning av kondensatsystemet. Kan kondensat och flashånga utnyttjas på ett bättre sätt för att tillhandahålla mer ånga till TM? Till uppgift 1 ställdes luft- och energibalanser upp över TM, och sedan gjordes mätningar på temperatur, flöde och fukthalt på in- och utgående luftflöden. För att undersöka hur förbrukningen lågtrycksånga i torkskåpet påverkas av tilluften gjordes försök där varvtal på tilluftfläktar och temperatur på tilluft varierades. Resultatet av luftbalansmätningarna var att inget undertryck rådde över torkskåpet, vilket innebär att all tilluft gick förvärmd in till torkningen. Energibalans över värmeåtervinningssystemet visade att ca 40 % av energin i utgående våtluft återvinns. Försök med varvtal och temperatur på tilluft visade att en ökning av varvtal från 750 rpm till 1000 rpm var gynnsamt vid hög produktion, samt att en temperaturökning på tilluft minskade förbrukningen lågtrycksånga i torkskåpet. Rekommenderade körinställningar: December-februari: 1000 rpm, alla produktionsnivåer Mars-november: 1000 rpm vid hög produktion (över 3 bars tryck på lågtrycksångan till skåpet) 750 rpm vid låg produktion (under 3 bars tryck på lågtrycksångan till skåpet) Till uppgift 2 gjordes mätningar på temperatur, flöde och fukthalt på utgående luftflöden från vakuumpumpar. Luftflödena från vakuumpumpar höll en temperatur på 40-50 °C, vilket var för lågt för att kunna användas till att förvärma torkluft till TM. Till uppgift 3 gjordes en kartering av kondensatsystemet inkluderande alla ång- och kondensatflöden kopplade till massatorkningen. Karteringen utfördes i AutoCAD. Eftersom försöket med temperaturökning på tilluft visade att lågtrycksångförbrukningen i skåpet minskade med ökad temperatur på tilluft, beräknades hur stor en ytterligare besparing lågtrycksånga skulle kunna bli om all tilluft förvärmdes av mellantrycksånga. Genom att använda mellantrycksånga för att förvärma all tilluft till torkskåpet skulle mängden tillgänglig lågtrycksånga till torkskåpet kunna ökas med 6 ton/h.

Throughout recent years, computer based programs has been applied to solve and analyze industrial problems. One of these developed programs is the Computational Fluid Dynamics (CFD) program. The purpose of implementing CFD analysis is to solve complex flow behavior which is not possible with ordinary calculus. The extensive application of CFD in the industry is a result of improved commercial CFD codes  in terms of more advance partial differential equations (PDE) describing various physical phenomena, CAD and mesh-grid generating tools and improved graphical user interfaces (GUI). Today, CFD usage has extended to fields such as aerodynamic, chemical process engineering, biomedical engineering and drying technology. As there is an on-going expansion of CFD usages in the industry, certain issues need to be addressed as they are frequently encountered. The general demand for simulation of larger control volumes and more advanced flow processes result in extensive requirement of computer resources. Numerous complex flow topics today require computer cluster networks which are not accessible for every company. The second issue is the implementation of commercial CFD codes in minor industrial companies is utilized as a black box based on the knowledge on fluid mechanic theory. A vital part of the simulation process is the evaluation of data through visual analysis of flow patterns, analysis on the sensitivity of the mesh grid, investigation of quantitative parameters such as pressure loss, velocity, turbulence intensity etc. Moreover, increased partnerships between industry and the academic world involving various CFD based design processes generally yields to a verbal communication interface which is a crucial step in the process given the fact of the level of dependency between both sides. The aim of this thesis is to present methods of CFD analysis based on these issues. In paper I, a heuristically determined design process of the geometry near the front trap door of an internal duct system was achieved by implementing the CFD code COMSOL MultiPhysics as a communication tool. The design process was established by two counterparts in the project in which CFD calculations and geometry modifications were conducted separately. Two design criteria presenting the pressure drop in duct and the outflow uniformity was used to assess geometry modifications conducted by a CAD-engineer. The geometry modifications were based on visual results of the flow patterns. The geometry modifications confirmed an improvement in the geometry as the pressure drop was reduced with 23% and the uniformity was increased with 3%. In paper II, volume-averaged equations were implemented in a tube-fin heat exchanger in order to simulate airflow. Focus was on achieving a correct volume flow rate and pressure drop (V-p) correlation. The volume averaged model (VAM) is regarded as a porous medium in which the arrangement of fins and tube bundles are replaced with volume-averaged equations. Hence, the computational time was reduced significantly for the VAM model. Moreover, experimental results of the (V-p) correlation showed good agreement with the VAM model.

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: A mineral concentrate drying process consisting of a hot gas generator, a flash dryer and a feeding section is found to be the bottleneck in the platinum concentrate smelting process. This operation is used as a case study for system identification and model-based control of dryers. Based on the availability of a month's worth of dryer data obtained from a historian, a third party modelling and control software vendor is interested in the use of this data for data driven model construction and options for dryer control. The aimed contribution of this research is to use only data driven techniques and attempt an SID experiment and use of this model in a controller found in literature to be applicable to the dryer process. No first principle model was available for simulation or interpretation of results. Data were obtained for the operation from the plant historian, reduced, cleaned and investigated for deterministic information through surrogate data comparison – resulting in usable timeseries from the plant data. The best datasets were used for modelling of the flash dryer and hot gas generator operations individually, with the hot gas generator providing usable results. The dynamic, nonlinear autoregressive models with exogenous inputs were identified by means of a genetic programming with orthogonal least squares toolbox. The timeseries were reconstructed as a latent variable set, or “pseudo-embedding”, using the delay parameters as identified by average mutual information, autocorrelation and false nearest neighbours. The latent variable reconstruction resulted in a large solution space, which need to be investigated for an unknown model structure. Genetic Programming is capable of identifying unknown structures. Freerun prediction stability and sensitivity analysis were used to assess the identified best models for use in model based control. The best two models for the hot gas generator were used in a basic model predictive controller in an attempt to only track set point changes. One step ahead modelling of the flash dryer outlet air temperature was unsuccessful with the best model obtaining a validation R2 = 43%. The lack of process information contained in the available process variables are to blame for the poor model identification. One-step ahead prediction of the hot gas generator resulted in a top model with validation R2 = 77.1%. The best two hot gas generator models were implemented in a model predictive controller constructed in a real time plant data flow simulation. This controller's performance was measured against set point tracking ability. The MPC implementation was unsuccessful due to the poor freerun prediction ability of the models. The controller was found to be unable to optimise the control moves using the model. This is assigned to poor model freerun prediction ability in one of the models and a too complex freerun model structure required. It is expected that the number of degrees of freedom in the freerun model is too much for the optimiser to handle. A successful real time simulation architecture for the plant dataflow could however be constructed in the supplied software. It is recommended that further process measurements, specifically feed moisture content, feed temperature and air humidity, be included for the flash dryer; closed loop system identification be investigated for the hot gas generator; and a simpler model structure with smaller reconstructed latent variable regressor set be used for the model predictive controller. / AFRIKAANSE OPSOMMING: 'n Drogings proses vir mineraal konsentraat bestaan uit drie eenhede: 'n lug verwarmer-, 'n blitsdroeër- en konsentraat toevoer eenheid. Hierdie droeër is geïdentifiseer as die bottelnek in die platinum konsentraat smeltingsproses. Die droeër word gebruik as 'n gevallestudie vir sisteem identifikasie asook model-gebasseerder beheer van droeërs. 'n Maand se data verkry vanaf die proses databasis, het gelei tot 'n derde party industriële sagteware en beheerstelsel maatskappy se belangstelling in data gedrewe modelering en beheer opsies vir die drogings proses. Die doelwit van hierdie studie is om data gedrewe modeleringstegnieke te gebruik en die model in 'n droeër-literatuur relevante beheerder te gebruik. Geen eerste beginsel model is beskikbaar vir simulasie of interpretasie van resultate nie. Die verkrygde data is gereduseer, skoon gemaak en bestudeer om te identifiseer of die tydreeks deterministiese inligting bevat. Dit is gedoen deur die tydreeks met stochastiese surrogaat data te vergelyk. Die mees gepaste datastelle is gebruik vir modellering van die blitsdroeër en lugverwarmer afsonderlik. Die nie-liniêre, dinamiese nie-linieêre outeregressie modelle met eksogene insette was deur 'n genetiese programmering algoritme, met ortogonale minimum kwadrate, identifiseer. Die betrokke tydreeks is omskep in 'n hulp-veranderlike stel deur gebruik te maak van vertragings-parameters wat deur gemiddelde gemeenskaplike inligting, outokorrelasie en vals naaste buurman metodes verkry is. Die GP algoritme is daartoe in staat om the groot oplossings ruimte wat deur hierdie hulp-veranderlike rekonstruksie geskep word, te bestudeer vir 'n onbekende model struktuur. Die vrye vooruitskattings vermoë, asook die model sensitiwiteit is inag geneem tydens die analiese van die resultate. Die beste modelle se gepastheid tot model voorspellende beheer is gemeet deur die uitkomste van 'n sensitiwiteits analise, asook 'n vrylopende voorspelling, in oënskou te neem. Die een-stap vooruit voorspellende model van die droeër was onsusksesvol met die beste model wat slegs 'n validasie R2 = 43% kon behaal. Die gebrekkige meet instrumente in die droeër is te blameer vir die swak resultate. Die een-stap vooruit voorspellende model van die lug verwarmer wat die beste gevaar het, het 'n validasie R2 = 77.1% gehad. 'n Basiese model voorspellende beheerder is gebou deur die 2 beste modelle van slegs die lugverwarmer te gebruik in 'n intydse simulasie van die raffinadery data vloei struktuur. Hierdie beheerder se vermoë om toepaslike beheer uit te oefen, is gemeet deur die slegs die stelpunt te verander. Die beheerder was egter nie daartoe in staat om die insette te optimeer, en so die stelpunt te volg nie. Hierdie onvermoë is as gevolg van die kompleks vrylopende model struktuur wat oor die voorspellingsvenster optimeer moet word, asook die onstabiele vryvooruitspellings vermoë van die modelle. Die vermoede is dat die loslopende voorspelling te veel vryheids grade het om die insette maklik genoeg te optimeer. Die intydse simulasie van die raffinadery se datavloei struktuur was egter suksesvol. Beter meting van noodsaaklike veranderlikes vir die droër, o.a. voginhoud van die voer, voer temperatuur, asook lug humiditeit; geslotelus sisteem identifikasie vir die lugverwarmer; asook meer eenvoudige model struktuur vir gebruik in voorspellende beheer moontlik vermag deur 'n kleiner hulp veranderlike rekonstruksie te gebruik.

Lipases são enzimas que catalisam a hidrólise de triacilgliceróis em ácidos graxos, mono e diacilgliceróis e glicerol. Em contraste com as esterases, lipases são ativadas apenas quando estão adsorvidas a uma interface óleo-água. Lipases têm sido amplamente utilizadas em muitos processos industriais, tais como química orgânica, formulações de detergentes e de produtos como cosméticos e farmacêuticos. A principal preocupação na produção de enzimas comerciais é a proteção da sua estabilidade em solução aquosa. A água facilita ou medeia uma variedade de vias de degradação física e química, durante as etapas de purificação, transporte e armazenamento. Por conseguinte, formulações sólidas são desenvolvidas para alcançar uma vida útil aceitável para essas substâncias. Spray drying é comumente usado como uma técnica de desidratação na indústria farmacêutica para fabricação de produtos em pó diretamente do estado líquido. No presente trabalho, a purificação e caracterização bioquímica de lipases produzidas pelo fungo endofítico Cercospora kikuchii, bem como os efeitos de adjuvantes no processo de secagem destas enzimas foram estudados. A lipase bruta foi purificada à homogeneidade através de cromatografia de interação hidrofóbica e gel filtração. A lipase foi purificada 5,54 vezes, com rendimento de 9% e a atividade específica de 223,6 U/mg. O peso molecular da enzima foi estimado em 65,1 kDa por SDS-PAGE e 73,5 kDa utilizando cromatografia de gel filtração, indicando que provavelmente trata-se de um monômero. A lipase mostrou um pH ótimo em 4,6 e uma temperatura ótima de 35°C. Cerca de 80,2% de sua atividade foi mantida após incubação a 40°C durante 2 horas. A Vmax e Km foram 10,28 mmol/min/mg de proteína e 0,03240 mM, respectivamente, utilizando pNPP como substrato. As lipases presentes no extrato bruto e as lipases ligadas ao micélio foram caracterizadas para avaliar o potencial de utilização em biocatálise. A lipases no extrato bruto apresentaram atividade máxima a 60ºC e pH 6,2, enquanto que as lipases ligadas ao micélio apresentaram atividade máxima a 50ºC e pH 5,4. Nos estudos de efeito da temperatura sobre a atividade enzimática, as lipases no extrato bruto mantiveram-se estáveis a 50°C, com 85,3% de atividade residual após 2 horas de incubação. As lipases ligadas ao micélio mantiveram pelo menos 75,1% de atividade residual após 2 horas de incubação a 80°C. Estes resultados mostram que as lipases de C. kikuchii têm propriedades cinéticas e termoestabilidade desejáveis para aplicações em biocatálise. As lipases presentes no extrato bruto foram secas em spray dryer com diferentes adjuvantes, e sua estabilidade foi avaliada. A recuperação da atividade enzimática após a secagem, com a adição de 10% de lactose, -ciclodextrina, maltodextrina, manitol, goma arábica, e trealose variou de 63 a 100%. A atividade da enzima foi totalmente perdida durante a secagem do extrato bruto na ausência de adjuvantes. A maioria dos adjuvantes utilizados manteve pelo menos 50% da atividade enzimática a 5°C e 40% a 25°C, após 8 meses de armazenagem. As lipases secas com 10% de - ciclodextrina mantiveram 72% da atividade a 5°C no mesmo período. A partir destes resultados preliminares foi realizada a otimização do processo de secagem utilizando -ciclodextrina, maltodextrina e lactose como adjuvantes. A análise estatística dos resultados experimentais permitiu a determinação das condições ótimas para a retenção da atividade enzimática (RAE), a saber: concentração de adjuvantes de secagem de 12,05%, temperatura de entrada do gás de secagem em 153,6oC e vazão do extrato enzimático alimentado de 9,36 g/min, para - ciclodextrina e maltodextrina como adjuvantes. Para lactose, o estudo mostrou que o aumento da quantidade de adjuvante de secagem e/ou diminuindo a temperatura do gás de entrada tem um efeito positivo sobre a retenção da atividade enzimática do produto seco. Após o processo de purificação foi realizada a secagem da enzima parcialmente purificada e da lipase pura, com estes três adjuvantes. A manutenção da atividade enzimática variou 90,6-100% quando foram utilizadas as condições ótimas para cada adjuvante de secagem. Concluindo, as lipases produzidas por C. kikuchii podem ser eficientemente secas por spray dryer, uma vez que a atividade enzimática foi mantida no extrato bruto, na lipase pura e na lipase semi-purificada submetidas à secagem. / Lipases are enzymes that catalyze the hydrolysis of triacylglycerols to fatty acids, mono and diacylglycerols, and glycerol. In contrast to esterases, lipases are activated only when they are adsorbed to an oilwater interface. They have been widely used in many industrial processes such as organic chemical, detergent and cleaning formulations and in products like cosmetics and pharmaceutical products. The main concern in the production of commercial enzymes is to protect their stability in aqueous solution. Water facilitates or mediates a variety of physical and chemical degradation pathways, active during protein purification, shipping and storage. Consequently, dry solid formulations are developed to achieve an acceptable protein shelf life. Spray drying is commonly used as a dehydration technique in the pharmaceutical industry for making powdery products directly from the liquid. In the present work, the purification and biochemical characterization of lipases produced by endophytic fungus Cercospora kikuchii as well as the effects of adjuvants on the spray drying process of theses enzymes were studied. The crude lipase was purified to homogeneity by hydrophobic interaction chromatography and gel filtration. The lipase purified was 5.54-fold with 9% recovery and the specific activity was 223.6. The molecular mass of the lipase was estimated to be 65.1 kDa using SDS-PAGE and 73.5 using gel filtration chromatography, indicating that the lipase is a monomer. The lipase demonstrated an optimum pH at 4.6, an optimum temperature of 35°C. About 80.2% of its activity was retained after incubation at 40°C for 2 hours. The Vmax and Km were 10.28 mol/min/mg protein and 0.03240 mM, respectively, using pNPP as substrate. The lipases present in crude extract and the mycelium-bound lipases were characterized in order to evaluate the potential for use in biocatalysis. The crude extract showed maximum activity at 60ºC and pH 6.2 while the myceliumbound lipases showed maximum activity at 50ºC and pH 5.4. In tests of the temperature effect on the enzymatic activity, the lipases in the crude extract was stable at 50°C, with 85.3% residual activity after 2 hours of incubation. The mycelium-bound lipases maintained at least 75.1% of residual activity after 2 h incubation at 80°C. These results show that the lipases of C. kikuchii have kinetic properties and stability characteristics suitable to applications in biocatalysis. The lipases present in crude extract were spray dried with different adjuvants, and their stability was evaluated. The recovery of the enzyme after drying with 10% of lactose, -cyclodextrin, maltodextrin, mannitol, gum arabic, and trehalose ranged from 63% to 100%; but the enzyme activity was lost in the absence of adjuvants. Most of the adjuvants used kept up at least 50% of the enzymatic activity at 5°C and 40% at 25°C after 8 months. The lipase dried with 10% of -cyclodextrin retained 72% of activity at 5°C. From these preliminary results the optimization of drying process using -cyclodextrin, maltodextrin and lactose as adjuvants was carried out. Statistical optimization of the experimental results allowed the determination of the processing conditions that maximized the retention of the enzymatic activity (RAE), namely: concentration of drying adjuvants of 12.05 %, inlet temperature of the drying gas of 153.6oC, and flow rate of the enzymatic extract fed to the dryer of 9.36 g/min, for the b-cyclodextrin and maltodextrin as adjuvants. For lactose as adjuvant the study showed that increasing the amount of drying adjuvant and/or decreasing the inlet gas temperature has positive effect on the retention of enzymatic activity of the dried product. After the purification process was carried out the drying of the partially purified enzyme and pure lipase, using these three adjuvants. The retention of enzymatic activity ranged from 90.6 to 100% when was used the optimal conditions for each drying adjuvant. Concluding, the lipases produced by C. kikuchii may be efficiently spray dried since its activity enzimatic was retained in crude extract, pure lipase and in semi-purified lipase after drying.

Made available in DSpace on 2017-07-10T15:14:31Z (GMT). No. of bitstreams: 1 DissertacaoVanderleyOliveira.pdf: 2301387 bytes, checksum: 90e5236543dbb525e9be975bfde530ca (MD5) Previous issue date: 2014-02-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present paper aimed at assessing the energy and economic parameters of grain drying, using a watertube boiler. Seeking an energy and economic evaluation of grain drying, it was chosen to research the drying of corn grains, using a column dryer double reuse model Comil CM 150 DR and a watertube boiler model CW 40. Studies were accomplished about the concepts and principles of drying; the technical data of the column dryer CM 150 DR; the Boiler Watertube CW 40; the alternative sources of solid fuels and Energy and Economic Analysis of the System. Considering that the main challenge of the appropriate storage of grains is to maintain the physical, chemical and biological properties the grains hold, imediatly after the harvest. The drying operation is an important part of the processing which precedes the storage, and extremely important for this process. The rational use of energy in the drying of agricultural products can contribute to an economy of fuel and obviously, to the reduction of the drying costs. The drying system with watertube boiler, showed the advanges as follows: stability and control of temperature; modulation of air flow; fuel economy; electrical energy economy; possibility of drying any kind of grain; possiblity of drying seeds; elimination of fire hazard. In the economical analysis, it was considered an investment of R$ 350.000,00; the minimum acceptable rate of return (MARR) of 3,5% per year, the net present value (NPV) in the period of 15 years, will be R$ 452.241,54. The internal rate of return (IRR) is 17,89 % per year. The project has presented profitability index (PI) of 1,29 % and rate of return (ROR) of 29 %, considered attractive. The Payback period, considered as the time required to recover the capital invested in the project, is 7 years, therefore staying positive and indicating economical viability. / O presente trabalho teve por objetivo avaliar os parâmetros energética e econômica da secagem de grãos, utilizando caldeira aquatubular. Visando uma avaliação energética e econômica da secagem de grãos, optou-se por pesquisar a secagem de grãos de milho, utilizando secador de coluna duplo reaproveitamento modelo Comil CM 150 DR e caldeira aquatubular modelo CW 40. Realizou-se estudos dos conceitos e princípios de secagem; os dados técnicos do secador de coluna CM 150 DR; a Caldeira Aquatubular CW 40; as fontes alternativas de combustíveis sólidos e Análise Energética e Econômica do Sistema . Considerando-se que o principal desafio do armazenamento adequado de grãos é manter as qualidades físicas, químicas e biológicas que os grãos possuem, imediatamente após a colheita. A operação de secagem é uma parte importante do processamento que antecede a armazenagem e de extrema importância para este processo. A utilização racional da energia na secagem de produtos agrícolas pode contribuir para a economia de combustível e, obviamente, para a redução dos custos de secagem. O sistema de secagem com caldeira aquatubular, apresentou as seguintes vantagens: estabilidade e controle de temperatura; modulação da vazão de ar; economia de combustível; economia de energia elétrica; possibilidade de secagem de qualquer tipo de grão; possibilidade de secagem de sementes; eliminação do risco de incêndio. Na análise econômica, considerou um investimento de R$ 350.000,00; a taxa média de atratividade (TMA ) de 3,5 % a.a., o valor presente líquido ( VPL ) no período de 15 anos, será de R$ 452.241,54. A taxa interna de retorno ( TIR ) é de 17,89 % a.a. O projeto apresentou índice de lucratividade ( IL ) de 1,29 % e taxa de retorno ( TR ) de 29 %, considerados atraentes. O período Payback, considerado como o tempo necessário para a recuperação do capital investido no projeto é de 7 anos, portanto ficando positiva e sinalizando viabilidade econômica..

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-10-18T15:04:53Z No. of bitstreams: 1 RODRIGO SÉRGIO FERREIRA DE MOURA -DISSERTAÇÃO PPGEA 2001..pdf: 7960772 bytes, checksum: 6c554557385690a7c05980568ee6742b (MD5) / Made available in DSpace on 2018-10-18T15:04:53Z (GMT). No. of bitstreams: 1 RODRIGO SÉRGIO FERREIRA DE MOURA -DISSERTAÇÃO PPGEA 2001..pdf: 7960772 bytes, checksum: 6c554557385690a7c05980568ee6742b (MD5) Previous issue date: 2001-03-16 / Capes / En este trabajo se ha estudiado las isotermas de desorción dei cajuil (Anacardium occidentale L.) vahedad roja, y los efectos de la temperatura y velocidad dei aire en la cinética dei secado de lo mismo, con vistas a la obtención de un modelo empírico que simbolizase el proceso, mediante un "planeamiento experimental". La humedad de equilíbrio fue obtenida con auxilio dei aparato Termoconstanter Novasina TH 200, que emplea el método estático; lo ajuste de los datos se hizo por regresión no linear, pelos modelos de BET, GAB, Halsey e Oswin, eligiéndose lo mejor mediante coeficiente de determinación (R2) y el modulo de la desviación relativa (P); la cinética dei secado, en camada fina, fue obtenida en uno secador de lecho fijo, para un rango de temperaturas variando de 35 a 65° C, y velocidades dei aire de secado de 0,9 a 1,9 m.s"1, de acuerdo con el planeamiento factorial completo (22 + configuración estrella). Adentren los modelos ajustados para las isotermas estudiadas, GAB fue el mejor, habido escogido para presentar las isotermas de desorción dei cajuil; se observo que los parâmetros Xm e C de esto modelo, disminuyeron con el aumento de la temperatura; se constato por médio de las curvas de secado que el tiempo gastado para secar el cajuil en las temperaturas de 35 y 40° C es el doble dei tiempo requerido a 65° C, y que la velocidad dei aire de secado no tiene influencia en el proceso; en la formulación de los modelos empíricos, el modelo de 2a orden presente un valor mayor de R2 y la relación entre F calculado e F tabulado vario de 6,04 a 19,86, aunque para el modelo linear esta relación fue de 0,27 a 5,40. Así, se pudo concluir que la cinética de secado es fuertemente afectada pela temperatura; el modelo de 2a orden es util para fines predectivos de la cinética de secado de esto producto; y, que mejor rango de operación se dio con la temperatura mas elevada. / Este trabalho teve como objetivos determinar as isotermas de dessorção do caju {Anacardium occidentale L.), "variedade" vermelha, e os efeitos da temperatura e da velocidade do ar na cinética de secagem deste produto, visando a obtenção de um modelo empírico que represente esse processo, mediante o emprego de um planejamento experimental. A umidade de equilíbrio foi obtida com o auxílio do equipamento Termoconstanter Novasina TH 200, utilizando-se o método estático-indireto; o ajuste dos dados foi feito através de regressão não linear, pelos modelos de BET, GAB, Halsey e Oswin, escolhendo-se o melhor mediante o coeficiente de determinação (R2) e o módulo do desvio médio relativo (P); a cinética de secagem, em camada fina, foi obtida em um secador de leito fixo, nas temperaturas variando de 35 a 65° C e velocidades do ar de secagem de 0,9 a 1,9 m.s"\ conforme o planejamento fatorial completo (22 + configuração estrela). Dentre os modelos ajustados às isotermas estudadas, GAB apresentou melhor ajuste dos dados experimentais, tendo sido escolhido para representar as isotermas de dessorção do caju; observou-se que os parâmetros Xm e C desse modelo, decresceram com o aumento da temperatura; constatou-se mediante as curvas de secagem que o tempo gasto para secar o caju nas temperaturas de 35 e 40° C é o dobro do tempo requerido a 65° C, e que a velocidade do ar de secagem não exerce influência no processo; na construção dos modelos empíricos, o modelo de 2â ordem apresentou um maior valor de R2 e a relação entre F calculado e F tabelado variou de 6,04 a 19,83, enquanto que no modelo linear esta relação foi de 0,27 a 5,40. Assim, pode-se concluir que a cinética de secagem é fortemente afetada pela temperatura; o modelo de 2a ordem é útil para fins preditivos da cinética de secagem desse produto; e, que a melhor faixa de operação é aquela correspondente à temperatura mais elevada.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-19T11:09:50Z No. of bitstreams: 1 SÍLVIO ALVES MOREIRA - TESE (PPGEP) 2013.pdf: 2013926 bytes, checksum: 3885f27bb2f69434b23233a4b6146158 (MD5) / Made available in DSpace on 2018-07-19T11:09:51Z (GMT). No. of bitstreams: 1 SÍLVIO ALVES MOREIRA - TESE (PPGEP) 2013.pdf: 2013926 bytes, checksum: 3885f27bb2f69434b23233a4b6146158 (MD5) Previous issue date: 2013-02-02 / Capes / No planeta em que vivemos, hoje com mais de sete bilhões de habitantes, é necessário rever conceitos para melhorar o mecanismo de produção e conservação de alimentos e evitar altos custos com tratamento de efluentes gerados por desperdício de matéria. Um exemplo significativo é o caso dos abatedouros de animais, especialmente bovinos, que lançam o sangue nos corpos de água causando poluição ambiental. Para minimizar estes impactos, foi desenvolvido um sistema automatizado de secagem por atomização para produção de proteína animal com o aproveitamento do sangue bovino. O sistema de secagem automático, construído com materiais de baixo custo e fácil aquisição, em módulos com possibilidade de alterações na configuração, apresenta capacidade de evaporação de 2,6 kg.h-1 de água e facilidade na operação. Os ensaios preliminares forneceram informações para atuação nas principais causas da baixa eficiência no processo de secagem por atomização. Com as ações adotadas foram obtidos resultados satisfatórios para a proposta do projeto. As principais características do sangue em pó obtido foram: boa fluidez; granulometria adequada à reconstituição e condições para armazenamento sem a petrificação do produto com a conservação da coloração. O sangue em pó com umidade em base úmida de 4,7% apresenta uma eficiência de produção de 67% e um rendimento de coleta de pó de 77%. A principal variável controlada foi a temperatura de saída, pela manipulação da vazão da suspensão, que têm influência direta na umidade do pó obtido. / Nowadays, with more than seven billion inhabitants living in the planet it is necessary to revise concepts to improve efficiency in the mechanisms of food production within the food chain and avoid high costs of wastewater treatment and high concentrations of organic matter. A significant example is the case of animals’ slaughterhouses, especially the bovine, that shed the blood into water bodies causing environmental pollution. To minimize these effects, an automated spray drying system was developed for animal protein production making use of the bovine blood. The automatic drying system, built with materials of cost low and acquisition easy in modules with a possibility of changes in layout, points out water evaporation capacity of 2.6 kg.h-1 and operation ease. Preliminary runs provided information to operate the main causes of low efficiency in the process of spray drying process. With the adopted actions satisfactory results were obtained for the project proposes. The main results were a blood powder with a particle size suitable for reconstitution, good fluidity and storage conditions for the product preserving its color without petrifying it. The blood powder with moisture content on a wet basis of 4.7% has a production efficiency of 67% and a powder collection efficiency of 77%. The main controlled variable was the output temperature through the suspension flow rate manipulation, which has a direct influence on the moisture content of the obtained powder.

Made available in DSpace on 2014-12-17T14:58:23Z (GMT). No. of bitstreams: 1 JoseMS_DISSERT.pdf: 2889418 bytes, checksum: 74b39d03124042e8cd8a6061bbd92425 (MD5) Previous issue date: 2012-05-23 / Licuri is a palm tree from the semiarid regions of Bahia State, Brazil. It is an important source of food and feed in that region, since their nuts are commonly eaten by humans and used as maize substitute for poultry feeding. The aim of this dissertation is to study the feasibility for use of natural convection solar dryers and forced being compared with the traditional drying outdoors for drying coconut licuri Syagrus coronate. The study led to the construction of two prototype solar dryer for carrying out experiments proving: model Solar Drying System Direct Exposure to Natural Convection built with wood, has a drying chamber with direct cover transparent glass laminates 4 mm, using techniques for proper isolation of the drying chamber. The two prototypes were comparatively analyzed for performance and drying efficiency with traditional extractive use by the community. Were evaluated the variables: time and drying rates and quality of the final samples of coconut licuri. The fruits were harvested and brought the town of Ouricuri, in the city of Caldeir?o Grande, BA for the experiments comparing the three methods of drying was used a standard load of 4.0 kg The quantitative analysis for the result of the drying rate was found in 74% yield and 44% for natural and forced convection respectively compared with the traditional drying. These drying rates represent variation 3-5 times lower. Drying using forced convection licuri showed better quality, was found in a reddish pulp, representing the quantities that were kept of the nutrient beta carotene, and not notice the flavor change from the previous system, the final cost of construction of this system were higher . The prototypes built competitive advantage and had testified fully to resolve the technical difficulties previously encountered in the production of products made of coconut licuri. Allowing add value and increase their potential use for the fruit extractive communities of semi-arid region of Bahia / O licuri (Syagrus coronata (Martius) Beccari) ? uma palmeira nativa do Brasil, largamente disseminada por todo o semi-?rido do pa?s. O fruto do licuri, conhecido pela mesma denomina??o da palmeira, ? totalmente comest?vel. Apesar do grande potencial nutritivo e oleaginoso do licuri, pouca aten??o tem sido dada para o estudo detalhado do valor nutritivo deste fruto. Nesta disserta??o ser? estudado a viabilidade para utiliza??o dos secadores solar de convec??o natural e for?ada (SSSEICF) sendo comparados com a secagem tradicional ao ar livre, para a secagem do coco licuri. O estudo levou a constru??o de dois prot?tipos de secador solar para a realiza??o de experimentos comprovativos: o Sistema de Secagem Solar de Exposi??o Direta e Convec??o Natural constru?do com madeira, possui uma c?mara de secagem direta com cobertura de lamina de vidro transparente de 4 mm, com utiliza??o de t?cnicas para o correto isolamento da c?mara de secagem e o Sistema de Secagem Solar de Exposi??o Indireta e Convec??o For?ada, fabricado com chapas de a?o galvanizado, tem a c?mara de secagem indireta com cobertura de l?mina de vidro transparente de 6 mm, tendo a utiliza??o de t?cnicas para correto isolamento da c?mara de secagem e a inser??o do equipamento de exaustor e?lico de ar respons?vel direto pela convec??o for?ada de ar da c?mara de secagem indireta. Os dois prot?tipos foram analisados comparativamente quanto ao desempenho e efici?ncia com a secagem tradicional em uso pela comunidade extrativista. Foram avaliados quanto as vari?veis: tempo e taxas de secagem e qualidade final das amostras de coco licuri. Os frutos foram colhidos e trazidos do povoado de Ouricuri, na cidade de Caldeir?o Grande BA, para a realiza??o dos experimentos comparativos entre os tr?s m?todos de secagem foi utilizada uma carga padr?o com 4,0 Kg. A an?lise quantitativa para o resultado da taxa de secagem, foi encontrado rendimento de 74% e 44% para o convec??o natural e convec??o for?ada respectivamente, em compara??o com a secagem tradicional. Essas taxas de secagem representam varia??o de 3 a 5 vezes menor. A an?lise qualitativa das amostras de fruto e das am?ndoas mostrou: que, a secagem utilizando a convec??o natural apresentou boa qualidade para o licuri, por?m foi constatada uma altera??o sensorial no sabor, conhecida como coco velado . A secagem utilizando a convec??o for?ada apresentou melhor qualidade do licuri, foi encontrada uma colora??o avermelhada na polpa, representando que foram mantidas as quantidades do nutriente beta caroteno e n?o se percebeu a mudan?a de sabor do sistema anterior, os custos finais de constru??o desse sistema foram maiores. Os prot?tipos constru?dos obtiveram vantagem competitiva e atestou perfeitamente para solucionar a dificuldade tecnol?gica encontrada anteriormente na produ??o de produtos a base do coco licur?. Permitindo agregar valor e elevar as possibilidades de aproveitamento do fruto pelas comunidades extrativistas da regi?o semi-?rida da Bahia