Conceptual Design Method for Energy Retrofit of Waste Gas-to-Energy Units

Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems h p://www.sdewes.o g/jsdewes Yea 2022, Volume 10, Issue 2, 100396 1 Jou nal o Sus ainable De elopmen W a e and En i onmen , o E ne g y Sy s ems 9257-1848ISSN jsdewes/o g.sdewes.www://h�ps O iginal Resea ch A icle Concep ual Design Me hod o Ene gy Re o i o Was e Gas- o-Ene gy Uni s Ví F eisleben1, Zdeněk Jegla*2 1Ins i u e o P ocess Enginee ing, Facul y o Mechanical Enginee ing, B no Uni e si y o Technology, Technická 2896/2, B no, Czechia e-mail: Vi .F eisleben@ u b .cz 2Ins i u e o P ocess Enginee ing, Facul y o Mechanical Enginee ing, B no Uni e si y o Technology, Technická 2896/2, B no, Czechia e-mail: zdenek.jegla@ u .cz Ci e as: F eisleben, V., Jegla, Z., Concep ual Design Me hod o Ene gy Re o i o Was e Gas o Ene gy Uni s, J. sus ain. de . ene gy wa e en i on. sys ., 10(2), 1090396, 2022, DOI: h ps://doi.o g/10.13044/j.sdewes.d9.0396 ABSTRACT Many indus ial was e gasses, especially om chemical and pe ochemical p ocesses, con ain combus ible subs ances enabling hei u iliza ion as a p omising ene gy sou ce. The mal oxida ion ep esen s a sui able and p o en echnology, which is, howe e , e y ene gy in ensi e in e ms o ex e nal uel demand dependen on exhaus hea eco e y e iciency. This pape p esen s a sys ema ic me hod de eloped o he Ene gy Re o i o indus ial uni s o he mal oxida ion o was e gases (was e gas- o-ene gy uni s) in o de o imp o e he uni s´ was e hea eco e y and hus o educe he ex e nal ene gy demand. This esul s in he educ ion o ope a ional cos s and emissions and imp o es was e gas ene gy u iliza ion. The me hod p ocedu e is u he applied o Ene gy Re o i o a speci ic was e gas- o-ene gy uni , whe e he uel sa ing o o e 30% was achie ed by he p oposed concep ual modi ica ions wi h a payback pe iod o only 5.5 mon hs. Finally, he de eloped me hod accu acy was success ully e i ied by compa ison wi h esul s o non-linea simula ion. KEYWORDS The mal oxida ion, Shi ing Flue Gas Line me hod, was e gas- o-ene gy uni , Ene gy Re o i , uel sa ing, VOC, CO. INTRODUCTION Many indus ial p ocesses gene a e was e gases. The composi ion o was e gas (WG) is dependen on many aspec s (such as he ype o p oduc p oduced in a p ocess plan , used echnology, e c.). Howe e , i usually con ains ha m ul subs ances, he e o e an app op ia e cleaning echnology mus be employed o p e en he emissions o he en i onmen . Fo example, he WGs p oduced in chemical and pe ochemical plan s o en con ain Vola ile O ganic Compounds (VOC) o ca bon monoxide (CO), which a e ha m ul o human heal h and he en i onmen . The a ious p oduc ion p ocesses, such as pain p oduc ion, oil e ine y, o ganic acid p oduc ion and o he s, gene a e ai pollu ed wi h some amoun o VOC and/o CO. Fu he , a huge amoun o he ai con amina ed wi h VOC is gene a ed in p in ing shops, especially in he au omo i e indus y. This pollu ed ai (as an indus ial WG) mus be ea ed be o e i s discha ge o he en i onmen . To con ol he VOC and CO emissions con ained in WGs a small concen a ion, he he mal oxida ion echnology has been ound an e ec i e and eliable aba emen F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 2 echnique which commonly eaches he pollu an emo al e iciency o o e 99%. I is applied o p ocessing la ge quan i ies o WG wi h a low concen a ion o combus ible subs ances (VOC/CO). The pollu an he mal oxida ion (decomposi ion) is in p inciple a con aminan lameless igni ion which esul s in a sudden empe a u e inc ease o p ocessed was e gas and pollu an he mal decomposi ion o ca bon dioxide (CO2) and wa e . The mal oxida ion akes place in a combus ion chambe (CC) a high empe a u es commonly anging be ween 730–850°C wi h necessa y esidence ime while lue gas (FG) is p oduced [1]. Main aining he p esc ibed empe a u es in he CC o he pollu an igni ion equi es in ensi e ene gy demand p o ided by a supplemen al uel, which is associa ed wi h high ope a ing cos s. In o de o imp o e he economic aspec o he uni ´s ope a ion, he was e hea con ained in a gene a ed lue gas is ypically used o ene gy pu poses (e.g., s eam gene a ion) and echnology pu poses (WG p ehea ing be o e i s en e ing CC o educe he supplemen al uel demand) h ough se ies o indi idual was e hea eco e y exchange s, i.e., h ough he Hea Reco e y Sys em (HRS). Fu he , FG cleaning echnology ( il e s, abso be s, sc ubbe s…) could be employed o emo e acid compounds, solid pa icles, o o he gaseous pollu an s i necessa y. A ho ough e iew o he ai pollu ion con ol echniques including he aba emen o VOC pollu ion was published by Schnelle e al.[1]. A simpli ied echnological layou o such was e gas o ene gy (WG E) uni is illus a ed in Figu e 1. Figu e 1. S anda d was e gas- o-ene gy uni Due o he con inuous uel p ice ise, he e is an e o o imp o e he exis ing WG E uni s in e ms o he uni s´ uel demand educ ion, i.e., pe o ming he Ene gy Re o i (ER). As sugges ed abo e, uel sa ing in a s anda d WG E uni is achie ed by p ehea ing he WG s eam be o e i s he mal p ocessing in he CC. As he WG p ehea ing is ealized by u iliza ion o he was e hea con ained in he lue gas (i.e., h ough some hea exchange s om HRS), he uel sa ings could be eached by he In eg a ion and In ensi ica ion o he exis ing HRS (Klemeš e al. [2]). A g ea e o has been pu in he las decades in o he esea ch o inc easing he p ocess e iciency in o de o educe he ex e nal u ili y demand ( uel, wa e esou ces) wi h espec o minimum in es men cos s. Mos cu en echniques and me hodologies ocused on e ec i e e o i and in ensi ica ion o hea exchange ne wo k (HEN) a e inspi ed by o a di ec ou come o he ini ial wo ks and p inciples o P ocess In eg a ion da ed in he la e 1970s wi h he disco e y o he Pinch Analysis concep (Linnho and Flowe [3]). Akpomiemie and Smi h [4], o example, b ough a no el me hodology o he cos -e ec i e hea ans e enhancemen in he exis ing HEN. Fu he , Jiang e al. [5] discussed a possibili y o he HEN e o i by eusing he exis ing hea exchange s. To imp o e he quali y o HEN e o i design, Lai e al. [6] also conside ed he in luence o physical dis ance be ween hea exchange s, p essu e d op and a ailable space o equipmen . The ad an ages o an indus ial plan ´s e o i on a p ac ical example o an F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 3 oil e ine y we e published by Ma on e al. [7].The comp ehensi e summa y o adi ional and mode n me hods o HEN e o i was published by Klemeš e al. [8]. The P ocess In eg a ion is no limi ed only o he opic o hea exchange in HENs. The mal ene gy con ained in he p ocess s eams is only a pa o he o al ene gy con en . P essu e le els o he p ocess s eams, o example, e lec he necessi y o mechanical wo k inpu , i.e., he pumping powe , which esul s in conside able elec ici y demand. Indus ial p ocesses can be designed o e o i ed wi h espec o minimiza ion o bo h, he hea du y and powe du y. Fu e al. [9] p esen ed he ad an ages o simul aneous wo k and hea in eg a ion applying g aphical and ma hema ical app oaches. Deng e al. [10] p oposed a me hod o u iliza ion o esidual p essu e ene gy based on Pinch Analysis. In summa y, Yu e al. [11] published a e iew o wo k and hea exchange ne wo ks (WHENs) e lec ing he cu en s a e-o - he-a . The e a e a ailable many analy ical me hods enabling ene gy eco e y imp o emen wi hin he s udied p ocess, bu he p ocess in eg a ion o la ge indus ial p ocesses ep esen s a complex p oblem, whe e ma hema ical p og amming is applied. Wissocq e al. [12], o example, p oposed a me hod based on a mixed-in ege -linea -p og amming (MILP) model o an op imal design o la ge indus ial plan s enabling a sui able echnology selec ion. Linea models´ applica ions equi e many simpli ica ions, which is associa ed wi h a educ ion in he esul s´ accu acy. To o e come his sho coming, Neme e al. [13] p oposed a wo-s age me hod inco po a ing he MILP model in combina ion wi h a mixed-in ege -nonlinea -p og amming (MINLP) model. Addi ionally, San os e al. [14] applied a MINLP model o pe o m he p ocess op imiza ion in e ms o hea and wo k du y minimiza ion. E en hough he p esen ed ad anced me hods can be used o educe he ene gy demand o indus ial p ocesses, hei achie able ene gy e iciency is s ill he modynamically limi ed. The e o e a eliable and sus ainable hea and powe sou ce is necessa y. Nowadays a numbe o mode n echnologies a e a ailable o he e ec i e p oduc ion o hea and powe . Fo example, he e is an e o o e o i he adi ional ene gy p oduce s, such as coal- i ed plan s, by cos e ec i e co-gene a ion echnology in oduc ion. The main goal is a deepe implemen a ion o enewable ene gy sou ces. The po en ial o in oducing co-gene a ion blocks p oducing powe om biomass o he exis ing coal- i ed plan was s udied by Kalina [15]. The mal and economic op imiza ion o his echnological solu ion was pe o med by Tańczuk e al. [16]. Fu he mo e, he ene gy sou ces could be used o gene a e powe and o p o ide hea ing and cooling simul aneously. Ka sa os e al. [17], o example, p oposed such a i-gene a ion sys em based on municipal was e gasi ica ion. As men ioned abo e, he e is a con inuous e o o implemen mo e enewable ene gy sou ces (e.g., sola and wind ene gy) o he cu en ene gy sys em. Howe e , ene gy p oduc ion om hese sou ces is uns able, which can cause s abili y issues in he powe g id. The powe g id capaci y o accep ance o a ious enewable ene gy sou ces was s udied by Taseska-Gjo gie ska e al. [18]. Fu he , Mo el e al. [19] p oposed a po en ial o powe g id capaci y inc ease by implemen a ion o ba e ies and exploi ing he kine ic ene gy o wind u bines. Va ious ypes o indus ial and municipal was es ep esen ano he signi ican ene gy sou ces wi h g ea po en ial o co e a pa o hea and powe consump ion. Compa ed o discussed sola and wind ene gy, an ad an age o indus ial plan s p ocessing was e is hei ela i ely s able ene gy gene a ion. On he o he hand, he main disad an age is he necessi y o supplemen al uel o he mal was e p ocessing. Howe e , in case o WG E uni s, he amoun o supplemen al uel can be signi ican ly educed by imp o ing he was e hea eco e y (as discussed abo e). The ER o WG E uni s can he e o e educe ope a ional cos s due o he uel demand educ ion, while he ene gy p oduc ion (e.g., s eam p oduc ion, he mal oil hea ing, e c.) is main ained. F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 4 Howe e , om he abo e desc ip ion o WG E uni s, i is ob ious ha he ER o he WG E p ocess canno employ hese sophis ica ed HEN e o i s a egies since HRS o WG E p ocess has subs an ially di e en speci ici y han he s anda d p ocess HEN, especially ha HRS does no con ain any U ili y Pa h. E en hough some me hods a e a ailable o an e icien e o i o HENs no con aining U ili y Pa h (such as Jegla and F eisleben [20]), none o hese me hods can be applied o he case o WG E uni s, as hei HRS does no allow c ea ing a new U ili y Pa h due o he absence o ho and cold u ili y. So, o ER o WG E uni s, i is necessa y o apply some speci ic e o i app oaches ocusing on he lue gas s eam as a was e hea sou ce and aking in o accoun he speci ici y o he WG E p ocess. As no sui able app oaches a e cu en ly a ailable o he ER o he WG E uni s, his esea ch wo k p esen s a decision making and e alua ing me hod, which is called he Shi ing Flue Gas Line (SFGL) me hod, ha ep esen s a concep ual design me hod o ER o WG E uni s. The SFGL me hod will be p esen ed in de ail in his a icle. I is a me hod de eloped o he e o i o WG E uni s in o de o educe hei ene gy demand, while high pollu an emo al e iciency is main ained. An accu a e e alua ion o uel sa ings is ano he impo an aspec o he p ope ER o WG E uni s. I could be pe o med by he p ocess non-linea simula ion using comme cial so wa e. This ad anced sys em modelling migh howe e be a d awback in e ms o acquisi ion cos s and also in e ms o applicabili y o WG E p ocess e o i a ge ing, whe e concep ual modi ica ions enabling he desi ed ene gy sa ings should be p oposed. The e o e, he non-linea simula ion does no ha e o be necessa ily con enien du ing he a ge ing and concep ual design s age. F eisleben and Jegla [21] p esen ed a simple and ai ly accu a e me hod o calcula e he uel sa ings o uni s o was e he mal p ocessing which does no equi e an ad anced non-linea sys em modelling. This analy ical me hod is based only on he ini ial empe a u e o he supplemen al uel/oxidize (Tini ), he Theo e ical Flame Tempe a u e (TTFT), he uel Lowe Hea ing Value (LHV), and he lue gas empe a u e (TCC) p esc ibed o su icien pollu an emo al (see Figu e 1). This calcula ion p ocedu e was applied in he de eloped SFGL me hod p esen ed in his pape . I should be emphasized ha he pu pose o he de eloped me hod is o enable ai ly accu a e WG E uni s modelling and a speci ic ER e alua ion and no ha o inding an op imal solu ion o ER. I is an analy ical app oach, which does no equi e in oduc ion o ad anced ma hema ical models and op imiza ion app oach p esen ed abo e. The de eloped SFGL me hod is desc ibed in he pape and u he p ac ically in oduced by i s applica ion o a case s udy o a speci ic WG E uni ´s Ene gy Re o i . The ob ained esul s a e hen compa ed o he non-linea simula ion o e i y he accu acy o he de eloped me hod. The non-linea simula ion was ca ied ou in so wa e CHEMCAD (in he la es e sion CHEMCAD 7) om Chems a ions Inc. [22] in combina ion wi h so wa e Xchange Sui e® om Hea T ans e Resea ch Inc. (HTRI) [23]. METHODS As men ioned in he In oduc ion sec ion, he Shi ing Flue Gas Line (SFGL) me hod is designed o ER o s anda d WG E uni s, i.e., he uni s o he mal p ocessing o was e gases, speci ically was e gases con aining combus ible subs ances such as VOC o CO. I bene i s om a ela i ely simple WG E uni echnological a angemen , whe e only a small numbe o WG p ocessing and hea eco e y equipmen is employed. The me hod enables es ima ing se e al key ea u es, such as he ollowing: • Flue gas hea eco e y e iciency and Ene gy Re o i a ge ing. The amoun o he lue gas was e hea which is cu en ly los is calcula ed and could be u ilized o educe he supplemen al uel demand. F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 5 • The concep ual design o he echnological modi ica ions ha a e equi ed o achie e he desi ed ene gy sa ings. • P ocess pa ame e s e-e alua ion, such as empe a u e p o iles and low a es o p ocess s eams and basic pa ame e s o newly added o modi ied equipmen (as e.g., hea exchange s´ hea loads). The main ad an age o he de eloped me hod is i s p ac icabili y and simplici y. I is based on a linea model o s udied p ocesses ha employs a limi ed numbe o WG p ocessing and FG hea eco e y equipmen , so he me hod can be pe o med by simple desk calcula ion. The main d awback o he de eloped me hod is i s limi ed applicabili y. I canno be e ec i ely applied o he wide ange o indus ial p ocesses as i was ailo -made o WG E uni s using hei speci ic cha ac e is ics, which a e discussed u he in he pape .The SFGL me hod is in p inciple a simple calcula ion p ocedu e suppo ed by g aphical ep esen a ion o pe o med modi ica ions o p omo e he designe ’s in e ac i i y when pe o ming he ER. The key equipmen is an indus ial u nace whe e he pollu an he mal oxida ion akes place. The SFGL me hod is he e o e inspi ed by analy ical app oaches o Fu nace Hea In eg a ion, especially by lue gas line ep esen a ion (o lue gas empe a u e-en halpy p o ile). The FG line was i s p oposed by Linnho and de Leu [24] and la e jus i ied by S ehlík e al. [25]. Following hese wo ks, Jegla e al. [26] hen in oduced he speci ic manipula ion wi h he FG p o ile o e icien u nace e o i . Inspi ed by his FG line ope a ion, he SGFL me hod p esen ed he e is di ided in o se e al sys ema ic s ages, which a e desc ibed below. The s udied uni da a ex ac ion The Ene gy Re o i p ocedu e s a s wi h a p epa a ion s age, whe e all key pa ame e s o he exis ing uni a e ob ained. I consis s o se e al poin s: • P ocess s eams and equipmen cha ac e is ics including he empe a u es, p essu es, composi ion, a e age speci ic hea capaci ies and low a es o all s eams p esen in he cu en WG E uni (FG, WG, s eam, ho wa e o ano he ene gy medium…). Fu he , he cha ac e is ics o applied hea exchange s a e ob ained, like ype, geome y, and hea loads. • Supplemen al uel/oxidize cha ac e is ics, which includes a uel Lowe Hea ing Value (LHV), Theo e ical Flame Tempe a u e (TTFT), ini ial empe a u e (Tini ), and mixing a io (K) o oxidize / uel mix u e being combus ed in WG E uni ´s u nace. • D awing o he empe a u e-en halpy diag am con aining empe a u e-en halpy p o iles (–he ea e e e ed o as jus p o iles) o all (ho and cold) p esen s eams. An example o such a diag am, co esponding o he uni echnological layou p esen ed in Figu e 1, is shown in Figu e 2. WG E uni s con ain ypically only one ho s eam, which is he FG coming ou o CC. In p ac ice, he spli ing o he FG s eam is no applied in WG E uni s due o he addi ional in es men cos s o he FG duc and dec eased ope a ional eliabili y. The FG p o ile (o FG line) is plo ed in an in e al be ween a CC ou le empe a u e (TCC) and a s ack empe a u e (Ts ack). This in e al ep esen s he amoun o hea , which is u ilized in he exis ing uni .The FG line is hen linea ly ex apola ed o he dew poin empe a u e (TDP), whe e he condensa ion is expec ed o occu . The in e al be ween Ts ack and TDP ep esen s an app oxima e alue o he amoun o hea wi h a po en ial o be u ilized bu is cu en ly los (Qloss). TDP is chosen as a limi empe a u e o a oid he gene a ion o he condensed subs ances (especially acidic) in FG o p e en he equipmen om co osion and damage. F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 6 The cold s eam p o iles a e no combined in o a Cold Composi e Cu e (unlike he s anda d p ac ice in he adi ional P ocess In eg a ion app oach based on Pinch Analysis [2]), bu hey a e plo ed sepa a ely. As he FG s eam is no usually spli , his g aphical ep esen a ion (shown in Figu e 2) e lec s he ac ual hea exchange a angemen in he exis ing HRS, whe e he FG hea is used a i s o a s eam gene a ion (Qs eam) and hen o WG p ehea ing (QWG). Figu e 2.Tempe a u e-en halpy diag am o exis ing Was e Gas- o-Ene gy uni Was e gas hea e in ensi ica ion As men ioned in he In oduc ion, he hea con ained in FG is commonly used o p ehea he WG s eam in o de o educe he uni ´s ene gy demand. Fo ha eason, he WG hea e is commonly employed as shown in Figu e 1. The WG p ehea ing enhancemen is ecommended as he i s hing o conside while he ER o he exis ing WG E uni is desi ed. This could be pe o med, o example, by inc easing hea ans e a ea (usually ela i ely cos ly), o implemen a ion o hea ans e in ensi ica ion echnology o he exis ing WG hea e , which p o ides a cheap solu ion o each he exchange enhancemen . The selec ion o app op ia e in ensi ica ion echnology depends on se e al aspec s, such as a ype and geome y o he exis ing WG hea e and media p ocess pa ame e s, such as empe a u es, ouling sensi i i y, o allowed p essu e d op. The analysis and compa ison o he mos sui able and e icien hea ans e enhancemen echnologies o ube WG hea e was pe o med, o example, in [27]. A e a sui able me hod o WG p ehea ing in ensi ica ion is selec ed, he uel sa ing could be e alua ed acco ding o he ollowing s eps: • Hea ans e inc ease e alua ion. Based on he selec ed enhancemen echnology o me hod, he in ensi ied hea ans e (Qin ) o he WG s eam is e alua ed. • Fuel sa ing calcula ion. I is pe o med using he equa ions (1) and (2) below [21]. 𝐹𝐹𝐹𝐹𝑉𝑉𝐶𝐶𝐶𝐶 =𝑛𝑛𝑐𝑐×𝐿𝐿𝐹𝐹𝑉𝑉 × 𝑇𝑇 𝑇𝑇𝑇𝑇𝑇𝑇 − 𝑇𝑇 𝐶𝐶𝐶𝐶 𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 − 𝑇𝑇𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖 (1) 𝛥𝛥𝑓𝑓 𝑠𝑠= 𝑄𝑄 𝑖𝑖𝑖𝑖𝑖𝑖 𝐹𝐹𝐹𝐹𝑉𝑉𝐶𝐶𝐶𝐶 (2) FHVCC de ines he uel ene gy con en u ilizable o keep he high empe a u e inside CC, Δ s is an achie ed uel sa ing and nc is a co ec ion ac o anging be ween 1.07-1.09. F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 7 • Flue gas low a e eassessmen . Because he supplemen al uel combus ed in CC is a pa o he FG s eam and uel sa ings a e achie ed by WG p ehea ing in ensi ica ion, he amoun o FG is educed by he alue o Δ s oge he wi h he co esponding amoun o combus ion ai (as an oxidize ) calcula ed acco ding o he oxidize / uel a io K (see equa ion (5) below). • Modi ied diag am plo . While he FG low a e is co ec ed, he diag am o he exis ing uni (Figu e 2) is modi ied as illus a ed in Figu e 3. By designed hea ans e in ensi ica ion, he WG p o ile is ex ended by he alue Qin , which causes a shi o he FG p o ile by he same alue o he igh . The FG g adien is also sligh ly inc eased due o he educed low a e. F om he abo e p ocedu e desc ibed and Figu e 3, he FG high sensi i i y o he ER modi ica ions is ob ious. This is an impo an aspec o be conside ed ca e ully du ing he concep ual design s age because i conside ably in luences he accu acy o he ob ained esul s. The FG p o ile shi causes a change o hea exchange d i ing o ces in pa icula hea exchange s, hus i is ecommended o e-e alua e he hea loads and o epea he calcula ion p ocedu e se e al imes un il he FG p o ile shi be ween i e a ions is educed o a minimum. Figu e 3. The exis ing WG hea e in ensi ica ion Inse ion o a new p ehea e Acco ding o he ene gy balance o a combus ion chambe , whe e he pollu an he mal decomposi ion akes place, he uel sa ings could be eached by p ehea ing any s eam en e ing he CC. Besides he WG p ehea ing, which is commonly employed (see Figu e 1), ano he iable choice is, o example, p ehea ing he combus ion ai (CA). I he WG E uni p ocesses se e al WG s eams, while some o hem a e no p ehea ed (mos ly mino s eams), he addi ional hea exchange s (p ehea e s) could be inse ed in o de o imp o e he FG hea u iliza ion by p ehea ing hose s eams. The usual ER equi emen is i s minimal impac on he gene a ion o ene gy media (e.g. s eam gene a ion illus a ed in Figu e 1). Fo his eason, new p ehea e s a e ecommended o be placed downs eam o he ene gy media gene a o s. A sui able posi ion is commonly a he end o he FG low pa h, whe e he was e hea (Qloss) could be di ec ly u ilized o educe he cu en uel demand wi hou signi ican in luence on o he hea exchange s in HRS. F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 8 The inse ion o a new p ehea e , howe e , in luences he FG low a e acco ding o he same p inciple as in he case o he exis ing WG hea e in ensi ica ion discussed p e iously. The p ocedu e o new p ehea e inse ion consis s o he ollowing s eps: • Exchange minimum app oach empe a u e (EMAT) alue de e mina ion. EMAT e alua ion is dependen on he exis ing HRS pa ame e s and is discussed, o example, by Zhu and Asan e [28]. • New p ehea e hea load calcula ion. Acco ding o he se EMAT alue and known s eam p ope ies, he hea load (Qp h) and co esponding media (FG and, o example, CA) inle /ou le empe a u es a e calcula ed. • Fuel sa ing calcula ion and lue gas low a e eassessmen . Ob aining he uel sa ing alue Δ s and FG low a e co ec ion ollows he same ules as in he case o he exis ing WG hea e in ensi ica ion. • Modi ied diag am plo . A g aphical ep esen a ion o he SFGL me hod is pe o med acco ding o sligh ly di e en ules han in he case o exis ing WG hea e in ensi ica ion. I is p esen ed in he case o CA p ehea e inse ion. When he FG low a e is co ec ed, he modi ied diag am can be plo ed as shown in Figu e 4. The di e ence be ween he in ensi ica ion o he exis ing p ehea e (Figu e 3) and he inse ion o he new one (Figu e 4) is ha he new p ehea e is placed o he le o he T-axis. This app oach causes only he FG line o a ion ins ead o shi ing o he igh as in he case o he exis ing p ehea e in ensi ica ion. Figu e 4. The new p ehea e inse ion The o a ion o he FG p o ile (as shown in Figu e 4) causes b eaking he CA p ehea e EMAT alue in an ini ial i e a ion. The CA low a e is also changed due o he eached uel sa ings. Fo hese easons, i is necessa y o pe o m se e al i e a ions o he p ocedu e desc ibed abo e un il he CA p o ile and FG p o ile (SFGL) a e s able and he EMAT alue equi emen is ul illed. The ER pe o med by he inse ion o a new p ehea e in luences he hea exchange d i ing o ces in exis ing hea exchange s in he same way as in he case o exis ing WG hea e in ensi ica ion desc ibed ea lie . Thus he e-e alua ion o hea loads in exis ing hea exchange s is ecommended. Howe e , i he FG low a e change is small, he dec ease in he hea ans e in exis ing hea exchange s could be neglec ed. The de eloped SFGL me hod is u he applied o a case s udy o a speci ic WG E uni p ocessing he WGs gene a ed in an ac ylic acid p oduc ion plan . F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 9 CASE STUDY The de eloped SFGL me hod he e is p ac ically in oduced by i s applica ion o he ER design o a speci ic indus ial WG E uni , which se es he mal ea men o was e gas p oduced mainly om an ac ylic acid p oducing p ocess. The p oduc ion p ocess is a sou ce o se e al was e gases con aining VOC and CO in low concen a ions (0.85 and 0.5 % ol). The cu en supplemen al uel consump ion is equi ed o be educed by a leas 30 % wi h as li le modi ica ion o he cu en uni as possible. The pa ag aphs below in oduce he s udied WG E uni wi h all key equipmen . Desc ip ion o he s udied uni The uni consis s o a u nace, e e ed o as a combus ion chambe (CC), whe e wo WG s eams a e he mally ea ed – main was e gas (MWG) and seconda y was e gas (SWG). The na u al gas bu ne is employed in he u nace o p omo e he mal oxida ion o he pollu an s and hus o gene a e a lue gas (FG) a a high empe a u e (800 °C). FG was e hea is a i s used o gene a e high-p essu e (HP) sa u a ed s eam, as a supplemen al hea ing medium in he plan , and o supe hea a medium-p essu e (MP) s eam as a medium o powe cycle (elec ici y gene a ion).The MWG is hen p ehea ed in he main was e gas hea e be o e en e ing he u nace (CC) o educe he supplemen al ene gy demand. The uni is illus a ed in Figu e 5. Figu e 5. S udied WG E uni The cu en uni is ene gy e y in ensi e, he e o e he Ene gy Re o i is eques ed in o de o educe he uni ´s uel consump ion. The SFGL me hod was applied o design he echnological modi ica ions in he cu en HRS enabling i o each he desi ed uel sa ing by imp o ing he FG hea eco e y. RESULTS AND DISCUSSION The uni ´s HRS consis s o h ee hea exchange s – HP s eam gene a o , MP s eam supe hea e , and MWG hea e as shown in Figu e 5. In he uni da a ex ac ion s age, hei basic p ocess and geome y cha ac e is ics we e p o ided (see Table 1). Acco ding o he desc ibed SFGL p ocedu e, he p ocess s eam cha ac e is ics a e gi en in Table 2 and uel/oxidize cha ac e is ics in Table 3. Wi h he ob ained da a, he empe a u e-en halpy diag am o he cu en uni was gene a ed (see Figu e 6). The FG line was ex apola ed o he dew poin empe a u e (TDP = 68.5 °C), which is acco ding o he FG composi ion calcula ed as he empe a u e o wa e apou condensa ion. F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 16 TDP lue gas dew poin empe a u e [°C] Tin inle empe a u e [°C] Tini ini ial empe a u e o oxidize / uel mix u e [°C] Tou ou le empe a u e [°C] Ts ack lue gas s ack empe a u e [°C] TTFT Theo e ical Flame Tempe a u e [°C] Δ s uel sa ing [kg/h] ΔmCA combus ion ai low a e educ ion [kg/h] ηDP lue gas u iliza ion he mal e iciency ela ed o dew poin , [%] Abb e ia ions CA combus ion ai CC combus ion chambe EMAT exchange minimum app oach empe a u e ER Ene gy Re o i FG lue gas HEN Hea Exchange Ne wo k HP high-p essu e (s eam) HRS Hea Reco e y Sys em LHV Lowe Hea ing Value MP medium-p essu e (s eam) MWG main was e gas SFGL Shi ing Flue Gas Line SWG seconda y was e gas VOC Vola ile O ganic Compound WG was e gas WG E Was e Gas- o-Ene gy (uni ) ACKNOWLEDGMENT This esea ch has been suppo ed by he p ojec LTACH19033 “T ansmission Enhancemen and Ene gy Op imised In eg a ion o Hea Exchange s in Pe ochemical Indus y Was e Hea U ilisa ion”, unde he bila e al collabo a ion o he Czech Republic and he People´s Republic o China (pa ne s Xi´an Jiao ong Uni e si y and Sinopec Resea ch Ins i u e Shanghai; SPIL VUT, B no Uni e si y o Technology and EVECO B no s. .o.), p og am INTER-EXCELLENCE, INTER-ACTION o he Czech Minis y o Educa ion, You h and Spo s; and by Na ional Key Resea ch and De elopmen P og am o China (2018YFE0108900). Fu he , his esea ch has been also suppo ed by he EU p ojec S a egic Pa ne ship o En i onmen al Technologies and Ene gy P oduc ion, unded as p ojec No. CZ.02.1.01/0.0/0.0/16_026/0008413 by Czech Republic Ope a ional P og amme Resea ch, De elopmen and Educa ion, P io i y Axis 1: S eng hening capaci y o high-quali y esea ch. REFERENCES 1. K. B. Schnelle, R. F. Dunn, and M. E. Te nes, Ai Pollu ion Con ol Technology Handbook, 2nd ed. Boca Ra on, Flo ida: CRC P ess, 2015, doi: h ps://doi.o g/10.1201/b19286. 2. J. J. Klemeš, P. S. Va bano , S. R. W. Alwi, Z. A. Manan, J. J. Klemeš, and S. R. W. Alwi, Sus ainable P ocess In eg a ion and In ensi ica ion: Sa ing F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 17 Ene gy, Wa e and Resou ces, 2nd ed. Be lin: De G uy e , 2018, doi: h ps://doi.o g/10.1515/9783110535365. 3. B. Linnho and J. R. Flowe , ‘Syn hesis o hea exchange ne wo ks: I. Sys ema ic gene a ion o ene gy op imal ne wo ks’, AIChE Jou nal, ol. 24, no. 4, pp. 633–642, 1978, doi: h ps://doi.o g/10.1002/aic.690240411. 4. M. O. Akpomiemie and R. Smi h, ‘Cos -e ec i e s a egy o hea exchange ne wo k e o i ’, Ene gy, ol. 146, pp. 82–97, Ma . 2018, doi: h ps://doi.o g/10.1016/j.ene gy.2017.09.005. 5. N. Jiang, W. Han, F. Guo, H. Yu, Y. Xu, and N. Mao, ‘A no el hea exchange ne wo k e o i app oach based on pe o mance eassessmen ’, Ene gy Con e sion and Managemen , ol. 177, pp. 477–492, Dec. 2018, doi: h ps://doi.o g/10.1016/j.enconman.2018.10.001. 6. Q. L. Yee, S. R. W. Alwi, and Z. A. Manan, ‘Hea Exchange Ne wo k Re o i Conside ing Physical Dis ance, P essu e D op and A ailable Equipmen Space’, Chemical Enginee ing T ansac ions, ol. 76, pp. 367–372, 2019, doi: h ps://doi.o g/10.3303/CET1976062. 7. S. Ma on, E. S ensson, R. Subiaco, F. Beng sson, and S. Ha ey, ‘A S eam U ili y Ne wo k Model o he E alua ion o Hea In eg a ion Re o i s – A Case S udy o an Oil Re ine y’, Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems, ol. 5, no. 4, pp. 560–578, Dec. 2017, doi: h ps://doi.o g/10.13044/j.sdewes.d5.0167. 8. J. J. Klemeš e al., ‘Hea ans e enhancemen , in ensi ica ion and op imisa ion in hea exchange ne wo k e o i and ope a ion’, Renewable and Sus ainable Ene gy Re iews, ol. 120, p. 109644, Ma . 2020, doi: h ps://doi.o g/10.1016/j. se .2019.109644. 9. C. Fu, X. Wang, and T. Gunde sen, ‘The impo ance o he modynamic insigh in Wo k and Hea Exchange Ne wo k Design’, 127-132, ol. 81, 2020, doi: h ps://doi.o g/10.3303/CET2081022. 10. J. Deng, Z. Cao, D. Zhang, and X. Feng, ‘In eg a ion o ene gy eco e y ne wo k including ecycling esidual p essu e ene gy wi h pinch echnology’, Chinese Jou nal o Chemical Enginee ing, ol. 25, no. 4, pp. 453–462, Ap . 2017, doi: h ps://doi.o g/10.1016/j.cjche.2016.07.020. 11. H. Yu, C. Fu, and T. Gunde sen, ‘Wo k Exchange Ne wo ks (WENs) and Wo k and Hea Exchange Ne wo ks (WHENs): A Re iew o he Cu en S a e o he A ’, Ind. Eng. Chem. Res., ol. 59, no. 2, pp. 507–525, Jan. 2020, doi: h ps://doi.o g/10.1021/acs.iec .9b04932. 12. T. Wissocq, S. Ghazouani, and S. Le Bou diec, ‘A me hodology o designing he modynamic ene gy con e sion sys ems in indus ial mass/hea in eg a ion p oblems based on MILP models’, Ene gy, ol. 185, pp. 121–135, Oc . 2019, doi: h ps://doi.o g/10.1016/j.ene gy.2019.06.124. 13. A. Neme , A. J. Isa iade, J. J. Klemeš, and Z. K a anja, ‘Two-s ep MILP/MINLP app oach o he syn hesis o la ge-scale HENs’, Chemical Enginee ing Science, ol. 197, pp. 432–448, Ap . 2019, doi: h ps://doi.o g/10.1016/j.ces.2018.06.036. 14. L. F. San os, C. B. B. Cos a, J. A. Caballe o, and M. A. S. S. Ra agnani, ‘Syn hesis and op imiza ion o wo k and hea exchange ne wo ks using an MINLP model wi h a educed numbe o decision a iables’, Applied Ene gy, ol. 262, p. 114441, Ma . 2020, doi: h ps://doi.o g/10.1016/j.apene gy.2019.114441. 15. J. Kalina, ‘Re o i ing o municipal coal i ed hea ing plan wi h in eg a ed biomass gasi ica ion gas u bine based cogene a ion block’, Ene gy F eisleben, V., Jegla, Z. Concep ual Design Me hod o Ene gy Re o i o … Yea 2022 Volume 10, Issue 2, 1090396 Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems 18 Con e sion and Managemen , ol. 51, no. 5, pp. 1085–1092, May 2010, doi: h ps://doi.o g/10.1016/j.enconman.2009.12.014. 16. M. Tańczuk, J. Sko ek, and P. Ba giel, ‘Ene gy and economic op imiza ion o he epowe ing o coal- i ed municipal dis ic hea ing sou ce by a gas u bine’, Ene gy Con e sion and Managemen , ol. 149, pp. 885–895, Oc . 2017, doi: h ps://doi.o g/10.1016/j.enconman.2017.03.053. 17. G. Ka sa os, T.-V. Nguyen, and M. Rokni, ‘T i-gene a ion Sys em based on Municipal Was e Gasi ica ion, Fuel Cell and an Abso p ion Chille ’, Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems, ol. 6, no. 1, pp. 13–32, Ma . 2018, doi: h ps://doi.o g/10.13044/j.sdewes.d5.0172. 18. V. Taseska-Gjo gie ska, M. Todo o ski, N. Ma ko ska, and A. Dedinec, ‘An In eg a ed App oach o Analysis o Highe Pene a ion o Va iable Renewable Ene gy: Coupling o he Long-Te m Ene gy Planning Tools and Powe T ansmission Ne wo k Models’, Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems, ol. 7, no. 4, pp. 615–630, Dec. 2019, doi: h ps://doi.o g/10.13044/j.sdewes.d7.0264. 19. J. Mo el, S. Oba a, and Y. Mo izane, ‘S abili y Enhancemen o a Powe Sys em Con aining High-Pene a ion In e mi en Renewable Gene a ion’, Jou nal o Sus ainable De elopmen o Ene gy, Wa e and En i onmen Sys ems, ol. 3, no. 2, pp. 151–162, Jun. 2015, doi: h ps://doi.o g/10.13044/j.sdewes.2015.03.0012. 20. Z. Jegla and V. F eisleben, ‘P ac ical Ene gy Re o i o Hea Exchange Ne wo k No Con aining U ili y Pa h’, Ene gies, ol. 13, no. 11, p. 2711, Jan. 2020, doi: h ps://doi.o g/10.3390/en13112711. 21. V. F eisleben and Z. Jegla, ‘Inno a i e Me hod o Fuel Sa ing Calcula ion Rela ed o Ene gy Re o i o The mal Was e P ocessing Uni s’, in P oceedings o he Enginee ing Mechanics 2020, S a ka, Czech Republic, No . 2020, ol. 26, pp. 142–145, doi: h ps://doi.o g/10.21495/5896-3-142. 22. ‘Chems a ions’, Chems a ions 2018. h ps://www.chems a ions.com/ [Accessed 02-Feb-2021]. 23. ‘HTRI | HTRI’. h ps://www.h i.ne / [Accessed 02-Feb-2021]. 24. B. Linnho and J. de Leu , ‘App op ia e placemen o Fu naces in he In eg a ed P ocess’, p esen ed a he IChem Symposium “Unde s anding P ocess In eg a ion II”, UMIST, Manches e , Ma . 1988. 25. P. S ehlík, S. Zage mann, and T. Gängle , ‘Fu nace in eg a ion in o p ocesses jus i ied by de ailed calcula ion using a simple ma hema ical model’, Chemical Enginee ing and P ocessing: P ocess In ensi ica ion, ol. 34, no. 1, pp. 9–23, Feb. 1995, doi: h ps://doi.o g/10.1016/0255-2701(94)00508-7. 26. Z. Jegla, P. S ehlık, and J. Kohou ek, ‘Plan ene gy sa ing h ough e icien e o i o u naces’, Applied The mal Enginee ing, ol. 20, no. 15, pp. 1545–1560, Oc . 2000, doi: h ps://doi.o g/10.1016/S1359-4311(00)00031-4. 27. V. F eisleben, ‘S udy on he Po en ial o an In eg a ed Was e- o-Ene gy Uni ’, M.Sc. Thesis, B no Uni e si y o Technology, B no, Czech Republic, 2019. 28. X. X. Zhu and N. D. K. Asan e, ‘Diagnosis and op imiza ion app oach o hea exchange ne wo k e o i ’, AIChE Jou nal, ol. 45, no. 7, pp. 1488–1503, 1999, doi: h ps://doi.o g/10.1002/aic.690450712. Pape submi ed: 21.10.2020 Pape e ised: 15.02.2021 Pape accep ed: 23.02.2021