ENERGY SAVINGS AND ENVIRONMENTAL PROTECTION APPLYING COGENERATION

Porast energetske učinkovitosti u industrijskoj proizvodnji uz istodobno smanjenje opterećenja okoliša može se postići primjenom kogeneracije kao i sekundarnih izvora, tj. povrata procesnog kondenzata. Predlaže se zamjena uobičajene odvojene opskrbe električnom energijom iz mreže i proizvodnjom topline u kotlovskom postrojenju kogeneracijom, odnosno kombiniranom proizvodnjom toplinske i električne energije (CHP). Analizirane opcije usmjerene na smanjenje potrošnje primarnog izvora ukazuju na značajne uštede. Usporedba odvojene proizvodnje toplinske i električne energije i konvencionalne proizvodnje električne energije rezultira poboljšanjem od oko 34%. Povrat procesnog kondenzata u konvencionalnom procesu daje uštedu od oko 7%, dok se u kogeneracijskom postiže oko 16%. Istovremeno sniženjem potrošnje goriva, za istu isporučenu energiju, uz porast ekonomičnosti ostvaruje se i smanjenje toplinskog i kemijskog opterećenja okoliša.Increased industrial energy efficiency and also lower environmental pollution could be achieved through the application of cogeneration as well as secondary sources i.e. reusing process condensate. Proposed here is replacement of the conventional system of separate electrical energy and thermal energy from a boiler plant with cogeneration, i.e. with combined heat and power production (CHP). Analysed options aimed at reducing the consumption of the primary source indicate significant savings. Comparison between cogeneration and conventional energy production results in savings of about 34%. Condensate heat recovery in the conventional process is about 7%, while in CHP process it reaches about 16%. In addition, fuel savings for the same amount of produced energy translate to gretaer economy and environmental benefits

Mogućnosti optimizacije procesa kompresije i ekspanzije u tekstilnoj industrij

Analizirane su mogućnost primjene i optimizacija procesa kompresije i ekspanzije u tekstilnoj industriji, kao što su predenje, bojadisanje, kemijsko čišćenje, teksturiranje, te hlađenje procesne vode i pneumatika odnosno pneumatsko upravljanje. U svakoj tekstilnoj tvornici optimizacija troškova uključuje kontrolu gubitaka kako vodene pare, tako i procesne vode, kondenzata i komprimiranog zraka. Tekstilna tvornica često proizvodi više komprimiranog zraka nego je to potrebno kako bi se osigurali dovoljno visoki tlakovi za rad potrošačkih uređaja. Pri tome valja naglasiti kako je optimizacija sustava s komprimiranim zrakom od presudne važnosti jer svaki potrošački uređaj zahtijeva specifičnu vrijednost tlaka zraka. To se postiže kalibriranjem izlaznog tlaka zraka u uređajima za generiranje komprimiranog zraka i osiguravanjem optimalnog tlaka zraka za svaki pojedini potrošački uređaj

Utvrđivanje volumena ljudskog tijela i mikroklimatskih pojasa odjeće 3D CAD tehnologijom skeniranja

Između odjevnih predmeta i tijela oblikuju se slojevi mikroklimatskog pojasa koji sadrži zrak i udio znoja isparenog s tijela ispitanika. Zrak mikroklimatskog pojasa utječe na vrijednost toplinske izolacije odjevnih predmeta i sustava. S obzirom na to da ISO 9920:2009 definira ukupnu toplinsku izolaciju odjeće s površine tijela u okoliš, što uključuje svu odjeću, zarobljene slojeve zraka i sloj zraka formiran oko tijela, može se zaključiti kako je suhi prolaz topline s tijela kombinacija otpora koji pruža odjeća i zarobljeni sloj zraka, odnosno toplina prenesena s izložene kože i topline koja prolazi kroz odjeću. Stoga je važno kvantificirati volumen zarobljenog mikroklimatskog sloja zraka. Da bi se istražio volumen mikroklimatskog zračnog pojasa, ispitanici su prvo skenirani beskontaktnom 3D CAD metodom, a potom je provedena ekstrakcija skenova i obrada reverznim modeliranjem pomoću programskog paketa Geomagic Design X. Kada je model obrađen, eksportirao se kako bi se izračunao volumen ili površina tijela pomoću programskog paketa Geomagic Verify

Optimization of energy savings in shoe sole production

Od 1970-ih godina najpopularniji potplati cipela jesu EVA potplati, napravljeni od etilen vinil acetata, kopolimera koji se sastoji od etilena i vinil acetata. Duromeri i elastomeri (gume), među koje ubrajamo i EVA polimere, čine oko 30% ukupne proizvodnje u tonama svih proizvedenih sintetskih polimera, pri čemu gume sintetskog podrijetla premašuju količinom proizvodnju guma prirodnog podrijetla. Imajući tu činjenicu na umu, energetske uštede u tvornicama proizvodnje gume iznimno su važne, a ovaj rad analizira potencijale energetskih ušteda u proizvodnji potplata za cipele napravljenih od etilen vinil acetata (EVA). EVA potplati za cipele jesu lagani, jednostavni za modeliranje, vodootporni i vlagootporni, jako elastični, amortiziraju udarce, dobri su toplinski izolatori, iznimno su otporni itd. Energetske uštede povratom topline procesnoga kondenzata prezentirane su u procesu proizvodnje potplata za cipele. Povrat topline kondenzata rezultira smanjenom potrošnjom pojne vode, znatnim uštedama goriva potrebnog za proizvodnju pare i rezultiraju smanjenom potrošnjom kemikalija potrebnih u proizvodnom procesu. Povrat vreloga procesnoga kondenzata u kotao rezultira smanjenjem potrošnje nafte 14,9 %. Također se smanjuje toplinsko zagađenje 95,3 %, dok se volumen ispušnih plinova smanjuje od 17,11 m3FG/kgNEC do 14,57 m3FG/kgNEC ili 14,8 %. Ovakav sustav omogućuje istodobnu uštedu nafte i smanjenje toplinskog zagađenja. Usporedbom procesa s povratom topline dimnih plinova u odnosu prema procesu bez povratka topline dimnih plinova, pokazuje uštede od 18,76 %, uz smanjenje temperature dimnih plinova sa 221° C na 137,39° C, pri čemu se volumen dimnih plinova smanjuje na 13,90 m3FG/kgP.Since 1970’s, the most popular shoe soles are (EVA) soles, made from Ethylene Vinyl Acetate, copolymer consisting of ethylene and vinyl acetate. The thermosets and elastomers (rubbers), among them accounting EVA, encompasses around 30% of the tonnage of all synthetic polymers produced, with the synthetic rubbers exceeding the tonnage of natural rubber. With that in mind, the energy savings in rubber processing plants are of great importance and the paper analyses the potential of energy savings in shoe soles production process made of Ethylene Vinyl Acetate (EVA). The shoe soles made from EVA are lightweight, easy to mould, water and moisture resistant, highly elastic, shock absorbent, great thermal insulators, highly durable, etc. The energy savings using the process return condensate in shoe sole production process are presented. Using the return condensate results in lower make up water consumption, substantial fuel savings needed to produce steam
and lower chemical consumption. Returning hot process condensate to the boiler results in oil savings of 14,9%. Also, the thermal pollution is reduced by 95,3%, while the volume of the flue gases is lowered from 17,11 m3FG/kgNEC to 14,57 m3FG/kgNEC or by 14,8%. Such a system enables both the oil savings and reduces the thermal pollution. The comparison of process with and without flue gases heat recovery shows fuel savings of 18,76%, while the temperature reduces from 221°C to 137,39°C and while the volume of the flue gases is lowered to 13,90 m3FG/ kgP

Energy Efficiency Optimization in Polyisoprene Footwear Production

The evaluation of energy efficiency improvements in polyisoprene footwear production is shown. By installing air preheater, combustion air natural gas consumption is reduced by 7%. Simultaneously, the boiler outlet flue gases’ temperature is decreased from 204 °C to 66.93 °C, providing a sound basis for both economical savings and energy efficiency improvements, as well as ecological benefits to the environment. The application of condensate heat recovery resulted in flue gases’ volume decreasing by 11.85% and a thermal pollution decrease of 91.34%. Combining air preheating by exhaust flue gases and condensate heat recovery resulted in a decrease in the flue gases’ volume by 17.97%, and in the temperature lowering to 66.93 °C. The energy consumption for a combined system on location φ=45°49′) with a collector field of 12.936 × 103 m2 was investigated. The hybrid system was calculated for four variants: (1) solarized process without flue gases’ heat recovery, (2) solarized processes with heat contend in flue gases using an air preheater, (3) solarized processes with condensate heat recovery, and (4) solarized processes with heat contend in flue gases using air preheater and condensate heat recovery. The highest fuel savings were shown in solarized processes with heat contend in flue gases using air preheater and condensate heat recovery, resulting in savings of up to 78.92%, while the flue gases’ volume decreased from 5390.95 m3FG/h to 932.12 m3FG/h

Energy Efficiency Optimization in Polyisoprene Footwear Production

The evaluation of energy efficiency improvements in polyisoprene footwear production is shown. By installing air preheater, combustion air natural gas consumption is reduced by 7%. Simultaneously, the boiler outlet flue gases’ temperature is decreased from 204 °C to 66.93 °C, providing a sound basis for both economical savings and energy efficiency improvements, as well as ecological benefits to the environment. The application of condensate heat recovery resulted in flue gases’ volume decreasing by 11.85% and a thermal pollution decrease of 91.34%. Combining air preheating by exhaust flue gases and condensate heat recovery resulted in a decrease in the flue gases’ volume by 17.97%, and in the temperature lowering to 66.93 °C. The energy consumption for a combined system on location φ=45°49′) with a collector field of 12.936 × 103 m2 was investigated. The hybrid system was calculated for four variants: (1) solarized process without flue gases’ heat recovery, (2) solarized processes with heat contend in flue gases using an air preheater, (3) solarized processes with condensate heat recovery, and (4) solarized processes with heat contend in flue gases using air preheater and condensate heat recovery. The highest fuel savings were shown in solarized processes with heat contend in flue gases using air preheater and condensate heat recovery, resulting in savings of up to 78.92%, while the flue gases’ volume decreased from 5390.95 m3FG/h to 932.12 m3FG/h

The Study on Effects of Walking on the Thermal Properties of Clothing and Subjective Comfort

Former studies done by other authors investigated the first- and second-layered air gaps beneath the clothing garments. None of the previous studies reported multidisciplinary clothing design testing approach linking both the objective measuring methods and subjective responses, while testing the thermal properties linked to a microclimatic volume formed between the layers of garments forming the ensemble. Neither was determined the limiting value of the microclimatic volume for outerwear garments, after which the thermal insulation will start to decrease due to convection. By taking the advantage of the precise three-dimensional (3D) body scanning technology and reverse engineering 3D CAD tool, the volume of the microclimatic air layers formed under outerwear garments was determined to study the impact of the ensemble’s microclimatic volume on the overall insulation value, measured by means of the thermal manikin. The jacket with the smaller microclimatic volume provided 5.2–13.5% less insulation than wider jackets, while the ensembles with tighter jackets showed 0.74–1.9% less insulation in static and 0.9–2.7% more insulation in dynamic conditions, thus proving that the limiting value of the microclimatic volume is greater than previously reported for three-layered ensembles. The effective thermal insulation value was reduced in average by 20.98–25.34% between standing and moving manikins. The thermal manikins are designed for steady-state measurements and do not work well under transient conditions, so three human subjects were employed as evaluators of the clothing thermal quality. In cooler climatic conditions, the measured physiological parameters and subjects’ grades pointed to discomfort while wearing ensembles with tighter jackets

Impact of hybrid system in polyester production

This study represents the evaluation of energy efficiency improvement using combination of natural gas, solar energy and flue gases heat recovery in polyester production. The analyzed energy sources are used for dry saturated steam generation. The energy consumption for combined system on location (φ = 45°49′) with collector field of 23.23 × 103 m2, was investigated. The hybrid system was calculated for four variants: (1) solarized process without flue gases heat recovery, (2) solarized processes with heat contend in flue gases using economizer, (3) solarized processes with heat contend in flue gases using an air preheater and (4) solarized processes with heat contend in flue gases using economizer and air preheater. The best method among presented sources is solution using economizer and the air preheater with natural gas, solar energy and flue gases heat recovery. The natural gas consumption is reduced for 67.82% which indicates that this solution is the optimal one. At the same time the volume of exhaust flue gases is diminished from 4947.1 to 1430.4 $m^3_{\text{FG}}$/h while simultaneously decreasing outlet temperature of 172.85°. Together with considerable energy savings, this hybrid system is sustainable and environmentally acceptable