Open Collections

UBC Undergraduate Research

An investigation into waste heat recovery methods for the UBC Microbrewery Bahrami, Nazanin; Huang, Michael; Huang, Aldrich; Tsai, Yiting 2013-04-04

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Notice for Google Chrome users:
If you are having trouble viewing or searching the PDF with Google Chrome, please download it here instead.

Item Metadata

Download

Media
18861-Bahrami_N_et_al_SEEDS_2013.pdf [ 915.25kB ]
Metadata
JSON: 18861-1.0108505.json
JSON-LD: 18861-1.0108505-ld.json
RDF/XML (Pretty): 18861-1.0108505-rdf.xml
RDF/JSON: 18861-1.0108505-rdf.json
Turtle: 18861-1.0108505-turtle.txt
N-Triples: 18861-1.0108505-rdf-ntriples.txt
Original Record: 18861-1.0108505-source.json
Full Text
18861-1.0108505-fulltext.txt
Citation
18861-1.0108505.ris

Full Text

UBC Social Ecological Economic Development Studies (SEEDS) Student Report       An Investigation into Waste Heat Recovery Methods for the UBC Microbrewery Nazanin Bahrami, Michael Huang, Aldrich Huang, Yiting Tsai  University of British Columbia APSC 262 April 4, 2013           Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report”.        APSC 262: Technology and Society II Project Final Report  An Investigation into Waste Heat Recovery Methods for the UBC Microbrewery   Written By: Nazanin Bahrami  Michael Huang  Aldrich Huang  Yiting Tsai   Tutorial Instructor: Dr. Paul Winkelman  Submitted: April 4th, 2013     Abstract   Any chemical process, including that of UBC’s Microbrewery, will inevitably release, along with its desired products, unused heat ener g y that is diss ipated int o the surrounding environment  “waste heat.” This report investigates two powerful strategies, nam el y that of Heat Inte grati on and Flue Gas Recover y and Separati on. These strate gies will achieve a three - fold purpose: to recov er as much waste he at as possi ble, hence dr asti call y  reducin g the economi c costs of the brewer y, to further minim iz e the environm ental footprint of the brewe r y, and to show that this practi ce of sust ainabili t y can be ex tended to other buildi ngs on the UBC campus .    Due to the lack of infor mation avail able about th e UBC Mic robre wer y, result s have been anal yz ed and pres ented on a per m 3  beer produc ed basis . Acco rdin g to literature findings, 1.09 GJ of energ y and $ 10.1 5  CAD are  requi red to produce ev er y m 3  of beer . Heat int egrati on ca n recove r 25 % of thi s en er g y, reduc e the cost of beer producti on b y $ 3.31/m 3 , and remove approx im atel y 25% of t he Gre enhouse Gas (GHG) and particulate emi ssi ons of the original brewe r y. Flue gas recov er y and separ ati on can recover 26% of the tot al heat ener g y, and can reduce the GHG and partic ulate emi ssi ons b y another 64%, but will inc rease the cost of bee r sli ghtl y b y $0.37/m 3 . The social benefits of the project include the cr eati o n of job opportuni ti es for lower - skil led operato rs and maintenanc e cr e ws, the relative ease in making the Brewer y a showcase for sust ainabi li t y (due to the Brewe r y alre ad y bein g a pop ular plac e fo r social acti vit ies), and the promo ti on of sim il ar waste heat recove r y con cepts in other UBC buil dings.    In summ ar y, th e two str ate gies pr esented in thi s report (Heat Inte grati on and Flue Gas Recover y) will result i n subst anti al ener g y r e coveries as well as dr amatic redu cti ons in environmental footprint s  and economi c costs .  Th e implementation of the se  strate gies  also shows a lar ge potential in gene ral social awa ren ess of sust ainabili t y, du e to the innate social nature of the Br ewe r y itself. Although the Br ewe r y itself an d the design conc epts outl ined in thi s report ar e in rudimentar y sta ges,  it is highl y recomm end ed t hat UBC conti nue  th ese effo rts in orde r so that the Brew er y, once buil t,  will trul y be  a p lac e for future students to learn and discuss sust ainabili t y.     Table of Contents  1.0 Introduction…………………………………………………………………… .. ……………1 2.0 Overview of Waste Heat Recovery Strategies………………………………………… ... 2 ~8  2.1 Strategy 1: Heat Exchanger Network (HEN) and Pinch Analysis…………… . …2~7 2.2 Strategy 2: Brewery Flue Gas Heat Recovery……………….. …………………...7~8 3.0 Economics……... …………………………………………………………………………9~12 3.1 Economics for Strategy 1 – HEN and Pinch Analysis……………………… .. …9~10 3.2 Economics for Strategy 2 – Flue Gas Recovery and Separation……………....10~12 3.3 Overall Economic Benefits and Other Economic Considerations………….……...12 4.0 Environmental Considerations…………………………………...……………………13~21 4.1 Heat Integration – Environmental Benefits………………………. …………...14~18 4.1.1 Fuel and Pollutant Reductions - Heat Integration…………………...14~16 4.1.2 Electricity Reductions – Heat Integration……………. ……………...16~18 4.2 Pollutant Reductions for Flue Gas Heat Recovery and Separation………… ... 18~19  4.3 Summary of Environmental Benefits (Pollution Reductions)………… . ……...20~21 4.4 Other environmental impacts…………… .. ………………………………………...21 5.0 Social Implications………………… ... …………………………………………………22~24 5.1 Job creation…………………………………………………………………… .. …..22 5.2 Student Learning…………………………………………………………… .. ……..23 5.3 Possible Case Study………………………...…………………………… ... ……23~24 5.4 Social Impacts: Conclusions………………………………………………… .. ……24 6.0 Conclusions and Recommendations……………………………………………………….25 References Appendix A: Heat Transfer and Heat Exchanger Sizing Calculations……….……….A1~A3  Appendix B: Flue Gas Absorber Cost Calculations………………………………...…..A4~A6         List of Figures and Tables  Figures: Figu re 1: Proc ess Flow Diagr am (PFD ) of a T ypic al Br ewer y (Slawit sch et al, 2011) …………..2 Figu re 2: Insides of a she ll - and - tube heat ex chan ger.  …………………………………………….4 Figu re 3: Tr ade - off between capital and utility costs, based on ∆T……………………………....5 Figu re 4: Hot and Cold C ompos it e Curves for Brewer y House and Pack a ging Op erati ons ……...6 Figu re 5: Proposed Bio gas Producti on Process Fl ow Dia gram (Weste rlund et al, 2012) ………...7 Figu re 6: Breakdown of Electricit y Gene rati on in BC …………………………………………..17 Figu re 7: T ypic al Indust r ial Anaerobic Digestor ………………………………………………..A7  Tables: Table 1: En er g y Consu mpt ion of Various Proc esses in a T ypical Br e wer y (Slawit sc h et al, 2011) ………………………………………………………………………………………………3 Table 2: Dist inction of High and Lo w - Tempe ratur e Processes Wit hin a Br e wer y ……………...14 Table 3: Poll utants Gene rated per m3 Natural Gas Burned…………………………………..….15 Table 4: Poll utants Gene rated per m 3  Beer Produ c ed ……………………………………………15 Table 5: Poll utant Reducti ons per m 3  Beer Produc ed for Natural Gas, b y Heat Inte gr ati on ….…16 Table 6: Poll utan ts Generated per kg Coal Burned…………………………………………...…17 Table 7: Poll utants Gene rated per m 3  Beer Produ c ed ……………………………………………17 Table 8: Poll utants Eli minated from Ele ctricit y Generati on, b y Heat Inte gr a ti on Strateg y ……..18  Table 9: Poll utant Reducti ons per m 3  Beer fo r Nat ural Gas, b y Flue Gas Re cover y …………....18  Table 10: Poll utant Reducti ons per m 3  Beer for El ectricit y , b y Flue Gas Re cover y …………….19  Table 11: Total Poll utant Reducti ons per m 3  Bee r Produced, b y Flu e Gas Strate g y …………….19 Table 12: Total Poll utants Gener ated per m 3  Beer Produced …………………………………… 20  Table 13: Total Poll utants Reducti on Achieved b y Heat Inte grati on and Flue Gas Recov er y …..20  1   1.0 Introduction   A “brewery” is a public drinking and so cial loc ati on, wher e the bee r is produced and consum ed on sit e.  In summ ar y, t he produ cti on process invol ves the tr ansformatio n of cereal gr ains int o malt, by soak ing the gr ains in water and all owing them to ger mi nate over a sp ecified period of time. The m alt is then boil ed to relea se its inner pol ysa cch ari de (su ga r) mol e cules which will under go chem ical rea cti on to produce alcoh ol, the basic chemi c a l component of bee r.   The UBC Microbr ewe r y is an ex tension of the  new  Student Union Buil din g (SUB), with the aim of gen erati n g minor revenu es for other S UB oper ati ons by the  minor - scale  s ale of bee r to students. It is also used as a “green process” displ a y  to the rest of the univ ersit y , since  the waste materials and ener g y gen erated b y the Microbr ew er y will be rec ycled or reused to other ex isting processes. One ex ampl e of an adjac ent proc ess was the SUB Greenhouse, and the origin al pla n was to recover as much waste heat ener g y as pos sibl e from the Microbrewer y and use it to power the Greenhouse oper ati ons. Howev er, as the Mic robrew er y buil din g loc at ion has be en rec entl y moved  to  the UBC far m, it will no longer be able to suppl y po wer fo r the SUB Gre enhouse (whose locati on did not change). Despit e the sudden chan ge, the students in thi s group had already set the project scope as “Waste heat recovery from the UBC Microbrewery,” and therefor e the report will sti ll treat thi s as the primar y obj ecti ve. This doe s not in an y wa y mak e the goal of the repo rt irrelevant to the original pr oblem statement, becaus e waste heat ex tracti on methods are sti ll being consi dered and ex plored. These strate gi es can be appli ed to an y process that gen erat es waste hea t in order to achiev e a three - fold objecti ve: to save subst anti al ene r g y costs incurred by the us e of tradit ional fuels and uti li ties, to drasti call y reduce environment al footprint s in the forms of gre enhouse emi ssi ons and waste heat, and to inc rease social int era cti on and awareness of UBC’s move towards more sustainable alternatives.       2   2.0 Overview of Waste Heat Recovery Strategies  2.1 Strategy 1: Heat Exchanger Network (HEN) and Pinch Analysis   In tr adit iona l chemi cal producti on processes  such as a brewe r y (we can consi der beer to be sim il ar to an y other comm odit y bein g produ c ed on a lar ge sc ale), sub stanti al economi c  and environmental  costs ar e incurred  in ord er to achie ve the ene r g y demands. These demands usu all y arise due to the require ment of heati n g or cooli ng of various fluid strea ms in the process. In a typical brew er y , th e lar gest ener g y costs oc cur in the heati n g of mashed malt  material in the wort separati on and heati ng (1 8% tot al en er g y),  wort boil ing/vapour condensati on (18% tot al ene r g y), and wort cooli n g pro cess es (35% tot al en er g y).  These en er g y - int ensive pr ocesses are hi ghli ghted in the following Process Flow Dia gr am (PFD ), as well as the f oll owing en er g y bre akdown table, both provided by Slawit s ch et al (2011):                Figure 1: Process Flow Diagram (PFD) of a Typical Brewery (Slawitsch et al, 2011)      18% Total energy  18% Total energy 35% Total energy 3   Table 1: Energy Consumption of Various Processes in a Typical Brewery (Slawitsch et al, 2011) Brewery Unit Operation/Process Process Fluid Temperature (C) Energy Consumption     kWh/week GJ/week GJ/year GJ/m3 beer % W aste heat in spent grain  75  26,315.00  94.73  4,926.17  0.05  4.99  Boil er start - up vapour lo sses  100  13,196.00  47.51  2,470.29  0.03  2.50  Vapour cond ensation  100  97,890.00  352.40  18,325.01  0.20  18.56  Vapour cond ensate recov er y  95  14,759.00  53.13  2,762.88  0.03  2.80  Wort Cooli ng  95  182,139.00  655.70  34,096.42  0.38  34.53  Brew House Cleanin g  70  9,164.00  32.99  1,715.50  0.02  1.74  Keg bott le washe r  30  10,475.00  37.71  1,960.92  0.02  1.99  Pasteuriz er  N/A  0.00  0.00  0.00  0.00  0.00  Packa ger  70  3,259.00  11.73  610.08  0.01  0.62  Bott le rinser  70  385.00  1.39  72.07  0.00  0.07  Crate Washer  40  1,862.00  6.70  348.57  0.00  0.35  Keg cle aning (outsides)  30  663.00  2.39  124.11  0.00  0.13  Keg washin g (insi des)  70  21,672.00  78.02  4,057.00  0.05  4.11  Keg pipi ng loss es  75  436.00  1.57  81.62  0.00  0.08  Keg steami n g vapours  70  2,854.00  10.27  534.27  0.01  0.54  Waste heat cooling compressors (cooli ng)  110  17,676.00  63.63  3,308.95  0.04  3.35  Wort separati on and Hea ti ng  30  92,626.00  333.45  17,339.59  0.19  17.56  Waste heat pressuriz ed ai r compressors  70  16,657.00  59.97  3,118.19  0.03  3.16  Boil er flue gas  130  15,519.00  55.87  2,905.16  0.03  2.94                Grand Total   527,547.00  1,899.17  98,756.80  1.10  100.00    The values stated in the table are for a bre wer y with an annual beer prod ucti on capacit y of 90,000 m 3 / yr. Ther ef ore, the en er g y valu es were no rmali z ed by div idi ng b y thi s annual capa cit y, in orde r to obtain a unit ener g y cost (GJ /m 3  beer) that can be appli ed to an y brew er y regardl ess of scale. Note that the item “Waste heat in spent grains” refers to the heat ene r g y avail able from the hot grains  as the y are cooled , and not the heat conten t of the grains wh en digested to produc e Bio gas (Se e Secti on 2.2 Strate g y 2: Bio gas Produ cti on). Obviousl y the underl yin g assum pti on is that all op erati n g and m aint enanc e  costs of said brewe r y  are scaled up, 4   or down in thi s case, by an identical, equivale nt factor. To keep thi s treatm ent sim ple, thi s assum pti on  is considered  to be vali d.    Slawitsch’s analysis shows that each approximately 1.09 GJ of energy is required per m 3  (1000 litres) of bee r pro duced. How ever, as Tab le 1 shows, man y pro ce ss streams are at high temperatur es (>70 o C ) and low temperatur es (<40 o C ). This proposed strate g y  invol ves the ph ysical cont act betwe e n hot and cold streams using Heat Ex chan ger s (HEXs ). HEXs ar e mechanic al devic es that provide ex cell ent heat tr ansfer ar ea throu gh  he at - conducti ve m aterials such as iron or steel. As the following dia gr am shows, the hot proc ess s tream which requir es cooli ng pass es its heat to the cold process stre a m which requires he ati ng. The amount of heat transfer red is prim aril y i nfluenced b y the temper ature diffe renc e betwe en the two streams (r efe r to the heat tr ansfe r  equ ati ons in Appendix 1).  The two stre ams ma y pass throu gh the heat ex changer in the sh ell side (lar ge, open m etal cas ing) or tube side (fine, holl ow tubes) dependin g on fluid pressure, corrosi veness, and othe r fa ctors.         Figure 2: Insides of a shell-and-tube heat exchanger.    Although the en er g y - s aving in centi ve l eads d esi gn ers to m ax im iz e temperat ure dif fer ence (∆T) betw een the hot an d cold streams, a trad e - of f ex ist s in that high - ∆T HEXs incur hi gh uti li t y costs (in form of superheated steam and water), and low - ∆T HEXs incur high capit al costs  (costs for mate rials of const ru cti on and inst all ati on co sts )  since the heat ex change area ne eds to b e ex tremel y lar ge.  The fi gu re below illust rates this tr ade - of f.     5            Figure 3: Trade-off between capital and utility costs, based on ∆T   Obviousl y a compromi s e must be struck in light of thi s trad e - of f. In the ch emi cal engin eerin g indus tr y, thi s is accompl ished b y th e use of the Pinch Analysis , which is defined as the  use of HEXs to  optimally pair-up hot and cold streams based on their respective temperatures, so that minimum total costs (capital + utility costs) are achieved . Pinch Anal ysis is usuall y perfo rmed on sophi sti cated proc ess si mul ators such as ASP EN Plus, since th e hand calculati on of heat tran sfer becom es impossi ble for a chemi c al proce ss with more than 10 int eracti n g streams. Als o, precise temper ature, pressure, he at capa cit y, and compos it ion of process stre ams must be known. The arr a y of hea t ex change rs used to acc ompl ish thi s is known as a “Heat Exchanger Network” (HEN). An example of Pinch Analysis, stream and heat ex changer pairin g is sho wn as the foll owin g:            6                Figure 4: Hot and Cold Composite Curves for Brewery House and Packaging Operations  Since the process details for the Microbrew er y are compl etel y unknown, the predicted energy savings achievable by HEN will be assumed to equal Slawitsch’s expected value of 25% (0.274 GJ /m 3  beer ener gy savin gs) of the tot al ener g y for producti on ( 1.09 GJ /m 3  beer  produced ).  Ex tra costs are ex pected due to the purch ase of pipes and fitti ngs to buil d thi s HEN; these ar e consi dered in the Econo mi c Anal ysis in Secti on X.X.    Since thi s heat int egr ati on process is relativel y si mpl e, as it onl y invol ves the moni to ring of various process temperatur es and pressures, operators can be hire d as  an yone with a basic apti tude for proc ess en gineerin g .  The ope rati on will remain straightfo rw ard as lon g as SOPs (Standard Ope rati onal Procedures ) ar e  prop erl y docum ented and op e r ators ar e ad equatel y informed about th e sa fe practi c es in the bre wer y. Th e most ch all en gin g task will invol ve the maintenance and servi c ing  of the heat ex change rs . This will likel y occur when the heat exchangers have undergone significant “fouling” (materi al has ac cumul ated insi de the heat ex changer tubes and ne ed to be clean ed out). For thi s, operators will need basic  hands - on ex perience with the ass embl y / disassembl y of  pipes and fitti ngs , as well as basic mech anical 7   apti tude to dism ount and disassembl e heat ex chan ge rs and cle an them . For tunatel y, plant servi ce shoul d onl y occu r once ever y yea r at most, and thi s will not be a frequent ta sk.   2.2 Strategy 2: Brewery Flue Gas Heat Recovery   Any bre wer y will undou btedl y us e fu els of some sort, be it ren ewabl e (bi omass) or non -renew able (co al, natural gas, etc.) to powe r its more ene r g y - int ensive ope ra ti ons  (which run at or above 100 o C )  or to prov ide superhe ated steam, s uch as durin g the pro ces s of wort boil ing. Th e waste gases, or “flue gases” resulte d from the consum pti on of fuels is often a hot mixture of gas es containin g steam (H 2 O), Carbon Diox ide (CO 2 ), Carbon Monox ide (CO), a mix ture of Nitrogen/S ulphur Ox ides (NO x /S O x ), which are al l greenhouse gases. Some uncombus ted hydro -carbons (molecul es co ntaining ca rbons s ingle - bo nded to hydro gen atom s) can also be in the flue gas, and th ese can be tox ic or car cinogenic shoul d the y be ingested b y hu mans. The combus ti on of coal can also rel ease the ex tremel y tox ic che mi cal, Mercu r y (Hg). Obvious l y if the br ew er y owner was con cern ed ab out his/ her operati ons both environmentall y and economi call y, the “gift from heaven” would be a strategy which could both extract waste heat from flue gas AND clean it at the same time.                Figure 5: Proposed Biogas Production Process Flow Diagram (Westerlund et al, 2012) 8   In thi s proposed str ate g y, flue gas enters the boil er as fuel and is combus t ed. As the flue gas mix ture ex it s the boil er, it passes throu gh a turbine which conv erts mechanic al ene r g y to electric al en er g y via a generato r. Then, the flue gas enters a sc rubbe r, which contains a pack ed bed of cer ami c material s which removes 38% of harmful particulates (gr eenhouse gases and hydro carbon mol ecules) on aver a ge ( W este rlund et al, 2012). An absorb er removes mos t of the steam (H 2 O) from the flu e gas, whe re it is cooled off in heat ex changers. The heat releas ed b y the cooli ng flue gas as well as t he latent heat rele ase d by th e cooli n g of H 2 O can be used for heat int egr ati on as detailed in Secti on 2.1: Strateg y 1.  The potential ener g y s avings of thi s strateg y are approx im atel y 50% of t he fuel en er g y required for proc esses such as wort boil ing/cooling and wort separ ati on/heati ng. This translates to an ene rg y savin gs of 26% (0.2 84 GJ /m 3  beer) of the tot al ener g y  (1.0 9 GJ /m 3  beer) requir ed for the brewer y.    Just like the last strateg y (heat int egr ati on), an y s tudents or persons int erested in process engin eerin g and op erati o n can be hi red as ope rat ors or m aint enanc e crew , giv en that th e y are provided the appropriat e do cumentati on. Safet y requirements will be more stringent fo r thi s strate g y, how ever, due to the mor e int ric ate nature of the pro cess. The f lue gas absorb er/sc rubber  will require more sp ec ializ ed personnel  to se rvice.  Chemi cal en gine ers ar e the suit able cand idates fo r the dail y pro cess oper ati on of the boil er, heat ex changers, and s crubbe r. Mechanical engineers will maintain the structural integrity of the plant’s various pipes and inst rumentation, as well as the operati on of the generato r. Electric al en g inee rs will be require d for the periodic cali brati on of various proc ess inst ruments and comput er i nterfa ces. A SOP will have to be written and documented so that the operators can be trained to run and maintain th e plant safel y. In terms of equipm ent service, sensit ive secti ons such as the packed bed absorb er will have to be replaced once eve r y couple of mo nths. Heat ex changers wi ll have to be serviced at most once ever y ye a r.  UBC en gineerin g studen ts or Co - op students are recomm ended for thi s task.       9   3.0 Economics   Table 1 sho ws that  0.71 GJ /m 3  of ener g y comes from proc esses ope rati n g >95 o C , and the remainder of the ene r g y (0.28 GJ /m 3 ) comes from processes oper ati ng un der 95 o C . Acco rdin g to Seider et al (2009), >95 o C processes are t ypi call y power ed b y non - rene wa ble fossil fuels such as natural gas and co al, an d the <95 o C pro cesses are usu all y po wer ed b y electricit y du e to the relativel y low he ati ng requirements. Assumi ng t hat thi s is the case for a typi cal br ewer y, the  costs of natur al gas an d electricit y can be eas il y obtained from Forti sBC and BC H ydro, respecti vel y. Accordin g t o Forti sBC , natural gas costs $2.98/GJ , which means that $2.11  is spent per m 3  beer produc ed on the high er - t emper ature processes. BC H yd ro cit es its electri cal costs in 2013 as $28.72/GJ , equati ng to $8.04 per m 3  beer produced. This means that beer producti on, in tot al, costs $10.15/ m 3 .   3.1 Economics for Strategy 1 – HEN and Pinch Analysis Usuall y a HEN (Heat Ex change r Network) uti li z ing the pinch anal ysi s must invol ve compl ete and ac curate knowledge of all tempe ratures, flowr ates, and heat capa cit ies of the process str eams invol ved in the heat int e grati on. S ince thi s data is not avail able to the students of thi s project, nor are appr ox im ate v alues of heat ener g y from the planned microbrew er y, th e he at ex changers, uti li ti es (superheat ed steam and water), as well as the pipi ng required cannot be esti mated on an absol ut e - value basis . Rather, li terature values of t ypic a l brewer y waste heat product ion are to be extracted from Slatwitsch et al (2011) then adjusted to an “energy per volume beer produced” (GJ/m 3  beer) basis in order to provide usef ul scale - down to the microbrew er y.    In the work of Slatwits ch et al (2011), a typic al brewer y with a prod ucti on scale of 90,000 m 3  beer per ye ar is estimated to release a tot al amount of 99,000 GJ of waste heat per ye a r. As propos ed previo usl y, 27.4% of thi s wast e heat, 27,000 GJ / yea r, can be recover ed using the HEN/P inch Anal ysi s strateg y. Althou gh th e proce ss details are unknown, a tradit ional Process Engin eerin g Ha ndbook by Seider et al (2009) states that the amount of heat ex change area can be calculated an d priced using thi s esti mated tot al waste heat value. Students takin g th e CHBE 459 course at UBC (4 th  Year Chemi cal Engine erin g Process Econo mi cs) confirms that the 10   methods stated in Seide r et al (2009) match the current siz ing/costi ng str ate gies, and that the y approach  an accura c y le vel of ± 50%. The equi pment costs of an y pro c ess equipm ent can be esti ma ted ac cordin g to its material of const r ucti on, pressure consi d erati ons, dim ension al adjust ments, and const r ucti on/i nstall ati on fees. Refer to Appendix A for a more detailed breakdown of these costs .   The result s from the Ap pendix state that a tot al of $60,927 CAD is requi red for th e tot al heat ex changer ar ea for a brewe r y producin g 90,000 m 3  beer/ ye ar. Dep en ding on the ex pected lifeti me of the bre wer y, the equival ent cost/ m 3  beer thes e he at ex chan ge rs will var y. For ou r case, we will ex pect the brew e r y to ope rate for 10 years ; therefo re, the heat ex changers will cost $0.67 /m 3  beer.    The amount of pipi ng required will mostly depend on the brewery’s plant la yout ( equipm ent, flowr ates, ener g y rates, etc. ) and pla nt design (ac cessi bil it y of uti li ti es, etc.). Since detailed proc ess data is not avail able, we assum e that the all process stre am s will be water - li ke in properties, and that the plant design of piping and instruments are “optimal.” In this case, the tot al cost of pipi ng can be esti mated as 45.6 % of the equipm ent cost, wh ich in our case are the heat ex chan ge rs (Lau, 2013). This translates t o an esti mated pipi n g cost of $0.31/m 3  beer produced. Finall y, we must consi der the ope ra ti ng costs fo r thi s strate g y. Accordin g to Lau (2013), oper ati ng l abor  and maintenance sum up t o 20% of total capit al cos ts, as a rou gh esti mate.  The tot al capit al cost from heat ex change rs an d pipes is sim pl y ($0.6 7+$0.31) /m 3  beer = $0.98/m 3  beer. The refo r e, the op erati n g and m aint enanc e costs are ro ughl y $0.20/m 3  bee r. s avings achieved b y heat int egr ati on.    Accordin g to Slatwits c h et al (2011), $81,100 CAD/ yr can be saved if 5% of the brewery’s total waste heat is integrated, for the base case brewery (with beer production rate of 90,000 m 3 / yr). This is eq uivalent to a t otal ener g y savings of $4.29/m 3  beer produced. Th ere fore, the net value of the heat int egrati on is sim pl y th e savings minus the ex tra incurred equipm ent costs , which are: $4.29/m 3  – ($0.67/m 3  + $0.31/m 3  + $0.20/m 3 ) = $3.1 1/ m 3  beer produ ced  over the base cas e. Ther efor e, heat int e grati on  shou ld seriousl y consi der ed as an ener g y savin gs alt ernati ve, from an econ omi c point of view.  11   3.2 Economics for Strategy 2 – Flue Gas Recovery and Separation      Brewery wort boiling is an energy - intensive part of the brewery. The Use of fossil fuels such as methane(CH4) in the boilers usually results in the formation of large amounts of flue gas. As detailed previously, typical flue gas compositions consist of greenhouse gases (CO2, CO, NOx/SOx,) water vapour and some unburnt hydrocarbon particulates, as well as mercury. In the flue gas recovery and separation strategy, the flue gases first enter a generator, where the mechanical energy of the gas is extracted and converted to electricity. The rest of the gas is a waste stream which is rich in greenhouse gases and soot particulates. The gaseous waste stream then flows through a packed bed scrubber where the particulates and wastes get absorbed in the packing of the scrubber. Since plant data for this brewery are unavailable, the estimates shown in this paper are based on order - of- magnitude estimates and typical industrial assumptions. Considering this study as the first stage of the preliminary study, the following estimates will have an error margin of about ±50% (Lau, 2013).  A packed bed scrubber is an adsorption unit operation, where a multi - phase stream is separated into the desired products (in our case, clean air) and undesired products (GHGs and particulates). One advantage of using a packed bed scrubber is that they have low pressure drops, which mean that the fluid usually does not need to be pumped, and thus pumping costs can be ignored. Moreover, scrubber packings are typically capable of achieving high mass transfer efficiencies, therefore allowing efficient separation of pollutants from the original gaseous waste stream. Although scrubbers have low capital costs, they incur substantial maintenance costs due to the frequency of service.  The following are cost ranges associated for a typical packed bed scrubber. The information comes from a combination of typical industry numbers provided by Seider et all(2009), as well as the United States Environmental Protection Agency (US EPA).       12   Capital Cost: $23,000 to $117,000 per sm3/sec ($11 to $55 per scfm) O & M Cost: $32,000 to $104,000 per sm3/sec ($15 to $49 per scfm), annually Annualized Cost: $36,000 to $165,000 per sm3/sec ($17 to $78 per scfm), annually Cost Effectiveness: $110 to $550 per metric ton ($100 to $500 per short ton), annualized cost per ton per year of pollutant controlled.   As stated earlier, the unavailability of plant size and data makes the calculations prone to large errors. However, the details are shown in the Appendix. After converting the numbers above to a per m3 beer basis, it is found that $0.49/m3 produced is required for the capital cost, and $0.67/m3 beer produced is the annual operating cost (the operating cost far exceeding the capital cost, as noted earlier). Taking into account that the heat savings achievable using the flue gas strategy amounts to ~$0.79/m3 beer, the approximate extra cost of this strategy comes out to be $0.37/m3 beer.  3.3 Overall Economic Benefits and Other Economic Considerations   Considering that it takes $10.15 to produce 1 m3 of beer, and that the net savings achieved by the two strategies combined is $3.31/m3 -  $0.37/m3 = $2.94/m3 beer, a significant economic saving (29.3%) is achievable by these two strategies alone. Therefore, there is an extremely strong incentive for these strategies, from the economic point of view.   In these analyses, however, there was a simplifying assumption that the equipment used (heat exchangers, pipes, absorber packings, etc.) would last indefinitely and would never require replacement. In a real implementation of these strategies, extra costs would have to be incurred for equipment replacement, but it is extremely difficult to measure them accurately due to varying plant lifetimes, future inflation rates, as well as the advance of technology which may make these strategies obsolete (better strategies may emerge in the future).         13   4.0 Environmental Considerations The heat int e grati on stra teg y invol ves th e use of numerous he at ex chan gers, pipes, and fitti ngs, in ord er to int e gr ate hot pro cess str eams with cold proc ess stre am s. If no heat int e grati on were pres ent, much mor e fossil fu els and ele ctricit y would be consum ed in orde r to me et the heati ng requir ements of the process. Al thou gh el ectricit y in BC is produ ced mainl y b y h ydro -electric dams, a small po rtion of it is produced outsi de of BC using less su stainable means, such as the combus ti on of fos sil fuels. Henc e, the bi ggest environmental ben efit to be reaped from the incorpo rati on of these str ate gies is the si gnificant reducti ons in greenhous e gases su ch as Carbon Diox ide (CO 2 ), Carbon Monox ide, (CO), Nitrous Ox ides (NO x ), and Sulphur Ox ides (SO x ). A mixture of these gases is known as “flue gas” in industrial terms, and they o ri ginate from the combus ti on of non - rene wable fossil fuels such as natural gas and co al. The y all contribut e to global warmin g, which in turn leads to anom ali es in season al cli mates. Carbon monox ide is ex tremel y deadl y and tox ic; a concentrati on as high a s 50 PPM and an ex posure time of 8 minutes is enough to kil l a full - grown human. Nitrous and Sul fur  ox ides are milder in tox icit y, but contribut e si gnifican tl y to acid rain. Uncom bust ed fuel particles su c h as h ydro carbons ar e also present in the flue gas, which caus e of fensiv e odours and ma y be car cinogenic to humans if inhaled or in gest ed. Fin all y, the ex tremel y tox ic el ement Mer cur y (Hg) m a y be pr esent from co al combus ti on, if the qu ali ty of co al is poor. The re fore, it is impe rati ve to quanti f y th e ex tent  to which the Heat Inte grati on and Flue Gas Re cov er y strate gies can eli mi nate the producti on of these tox ic and environmentall y - un friendl y gas es and particulates.    Accordin g to Slawit sch et al  (2011) , most brewe r y process es operati n g under 95 o C ar e heated  b y ele ctricit y, due to the relativel y low er heat dem ands. How ever, t he proc esses op er ati ng at or above 95 o C are usu all y po wer ed b y non - r en ewable fossil fu els, with natural gas bein g the most comm on fuel.  Belo w is a recount of the var ious brewer y proc esses, and the ones that are likel y to be fu eled b y nat ural gas ar e hi ghli ghted in yell ow.      14   Table 2: Distinction of High and Low-Temperature Processes Within a Brewery Brewery Unit Operation/Process Process Fluid Temperature (C) Energy Consumption     kWh/week GJ/week GJ/year GJ/m3 beer % W aste heat in spent grain  75  26,315.00  94.73  4,926.17  0.05  4.99  Boil er start - up vapour lo sses  100  13,196.00  47.51  2,470.29  0.03  2.50  Vapour cond ensation  100  97,890.00  352.40  18,325.01  0.20  18.56  Vapour cond ensate recov er y  95  14,759.00  53.13  2,762.88  0.03  2.80  Wort Cooli ng  95  182,139.00  655.70  34,096.42  0.38  34.53  Brew House Cleanin g  70  9,164.00  32.99  1,715.50  0.02  1.74  Keg bott le washe r  30  10,475.00  37.71  1,960.92  0.02  1.99  Pasteuriz er  N/A  0.00  0.00  0.00  0.00  0.00  Packa ger  70  3,259.00  11.73  610.08  0.01  0.62  Bott le rinser  70  385.00  1.39  72.07  0.00  0.07  Crate Washer  40  1,862.00  6.70  348.57  0.00  0.35  Keg cle aning (outsides)  30  663.00  2.39  124.11  0.00  0.13  Keg washin g (insi des)  70  21,672.00  78.02  4,057.00  0.05  4.11  Keg pipi ng loss es  75  436.00  1.57  81.62  0.00  0.08  Keg steami n g vapours  70  2,854.00  10.27  534.27  0.01  0.54  Waste heat cooling compressors (cooli ng)  110  17,676.00  63.63  3,308.95  0.04  3.35  Wort separati on and Hea ti ng  30  92,626.00  333.45  17,339.59  0.19  17.56  Waste heat pressuriz ed ai r compressors  70  16,657.00  59.97  3,118.19  0.03  3.16  Boil er flue gas  130  15,519.00  55.87  2,905.16  0.03  2.94                Grand Total   527,547.00  1,899.17  98,756.80  1.10  100.00   4.1 Heat Integration – Environmental Benefits  4.1.1 Fuel and Pollutant Reductions - Heat Integration  The heat requirements for the highli ghted proc es ses in Table 2  add up to a total of 0.71  GJ /m 3  beer. According t o FortisBC’s site, natural gas has an average energy content of 1,000 Btu/ ft 3 , or 37.3 MJ /m 3 . Therefo re, 18.1 m 3  natur al gas is requir ed to pro duce ev er y m 3  of bee r. Accordin g to NaturalG as .org, th e possi ble poll utants released b y the fu el consi st of the following :   15   Table 3: Pollutants Generated per m3 Natural Gas Burned: Pollutant Output (kg pollutant/m3 NG) C arbon Diox ide (CO 2 )  1.87  Carbon Monox ide (CO)  6.41x 10 - 4  Nitrogen Ox ides (NO x )  1.47x 10- 3  Sulfur  Ox ides (SO x )  1.60x 10- 5  Hyd roca rbon Particulates  1.12x 10 - 4    Hence, th e amount of pol lut ant gen erated per m 3  beer produ ced can be appr ox im ated as:   Table 4: Pollutants Generated per m3 Beer Produced Pollutant Output (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  33.8  Carbon Monox ide (CO)  1.16 x 10 - 2  Nitrogen Ox ides (NO x )  2.66 x 10- 2  Sulfur  Ox ides (SO x )  2.90 x 10- 4  Hyd roca rbon Particulates  2.03 x 10 - 3   T he tot al heat savin gs achievabl e ac ross the enti re brew er y usin g Strate g y 1 (He at Inte grati on) is approx im atel y 25%, as detailed in Secti on 2.1 .  A ssum in g t hat thi s reflects  a 2 5% reducti on of natural ga s requirements for the brewe r y  pro cesses that require temper atures of >100 o C , t he associate d poll utants (CO 2 , CO, NO x /S O x  and particu late s) will also be redu ce d by 2 5%.  Th er efor e, the foll owing poll utant reduct ions are achievable:          16   Table 5: Pollutant Reductions per m3 Beer Produced for Natural Gas, by Heat Integration Pollutant Output Reduction (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  8.45  Carbon Monox ide (CO)  2.90 x 10 - 3  Nitrogen Ox ides (NO x )  6.67 x 10- 3  Sulfur  Ox ides (SO x )  7.27 x 10- 5  Hyd roca rbon Particulates  5.10 x 10 - 4    Other environmental con siderati ons for the Heat Integr ati on strate g y includ e the concr ete, metals (stainl ess steel), and other materi als used i n heat ex chan ge rs, p ipes, and fitti ngs. Althou gh it is possi ble to esti mate the amount of such materials required to pr oduce thes e items, th e environmental effe cts ar e indi rect and dif ficult to quanti f y. Fo r ex ampl e, the process es that produce con crete or sta inl ess steel ma y be sust ainable or unsust ainable, dependin g on the company’s ethical and environmental policies. Therefore, the possible indirect environmental im pacts of procurin g thes e materials are point ed out, but not ex plored, in this report.   4.1.2 Electricity Reductions – Heat Integration  Accordin g to Tabl e 2 , 0.38GJ /m 3  beer is require d for the lowe r - temper at ure proc esses (<95 o C ), and is t ypic all y suppl ied by electricit y. Typic all y, 80% of electri cit y in produced BC is suppl ied by h yd roele ctr ic dams, with the remaining 20% suppl ied by fossil fuels from powerplants outsi de of BC. The 20% of the electricit y will be assum ed as gene rated b y coal. Appl yin g the s ame prop orti ons to the brew er y, it can be assum ed that 0.3 04 GJ /m 3  is gener ated by h ydro - ele ctric means, a nd 0.076 GJ /m 3  is gener ated b y coal.         17         Figure 6: Breakdown of Electricity Generation in BC   Accordin g to a stud y per formed  b y the Universit y of Washin gton, the en er g y content of coal is 16.5 MJ /kg. Thi s means th at 4.61 kg coal is required to produ ce ever y m 3  of beer. NaturalGas.o r g also prov ides a table of poll utants gen erat ed b y the combus ti on of coal:   Table 6: Pollutants Generated per kg Coal Burned: Pollutant Output (kg pollutant/kg coal) C arbon Diox ide (CO 2 )  1.48  Carbon Monox ide (CO)  1.48x 10 - 3  Nitrogen Ox ides (NO x )  3.24x 10- 3  Sulfur  Ox ides (SO x )  1.84x 10- 2  Hyd roca rbon Particulates  1.95x 10 - 2  Mercur y  1.13x 10 - 7    Hence,  th e amount of pol lut ant gen erated per m 3  beer produ ced can be appr ox im ated as:  Table 7: Pollutants Generated per m3 Beer Produced Pollutant Output (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  6.82  Carbon Monox ide (CO)  6.82x 10 - 3  Nitrogen Ox ides (NO x )  1.49x 10- 2  Sul fur  Ox ides (SO x )  8.48x 10- 2  Hyd roca rbon Particulates  8.99x 10 - 2  Mercur y  5.21x 10 - 7   Hydro (80%) Coal (20%) 18    Assumi ng that up to 25% of the heat requirem e nts in the lower - temper a ture proc esses (<95 o C ) can be saved b y heat int e grati on, 25% of the tot al electricit y requ irement can be sav ed, and hen ce 25 % of the poll utants from the comb usti on of coal can be av oided, result in g in the following poll utant redu c ti ons:   Table 8: Pollutants Eliminated from Electricity Generation, by Heat Integration Strategy Pollutant Output Reduction (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  1.71  Carbon Monox ide (CO)  1.71 x 10 - 3  Nitrogen Ox ides (NO x )  3.73 x 10- 3  Sulfur  Ox ides (SO x )  2.12 x 10- 2  Hyd roca rbon Particulates  2.25 x 10 - 2  Mercur y  1.30 x 10 - 7    4.2 Pollutant Reductions for Flue Gas Heat Recovery and Separation  Accordin g to Secti on 2.2 , the flue gas recov er y and absorption s ystem wil l recov er 26% of the tot al waste h eat from the brewer y. Assumi ng that thi s proportional  const ant is equal to the savings achieved on the natural gas  and electricit y  consum pti on s  for  the brewe r y, and accounti n g for the fact that the flue gas sc rubber remov es 38% of the gr eenho use gas es and carbon particulates gener ated by th e boil ers, the poll ut ant redu cti ons  achi eved by thi s heat recover y strate g y can be sim pl y ca lculated as:   Table 9: Pollutant Reductions per m3 Beer for Natural Gas, by Flue Gas Recovery Pollutant Output (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  21.6  Carbon Monox ide (CO)  7.42 x 10 - 3  Nitrogen Ox ides (NO x )  1.70 x 10- 2  Sulfur  Ox ides (SO x )  1.86 x 10- 4  Hyd roca rbon Particulates  1.30 x 10 - 3   19   Table 10: Pollutant Reductions per m3 Beer for Electricity, by Flue Gas Recovery Pollutant Output (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  4.36  Carbon Monox ide (CO)  4.36 x 10 - 3  Nitrogen Ox ides (NO x )  9.54 x 10- 3  Sulfur  Ox ides (SO x )  5.43 x 10- 2  Hyd roca rbon Particulates  5.75 x 10 - 2  Mercur y  3.33 x 10 - 7     Hence, the flu e gas recover y strate g y achiev es the followin g comb ined poll utant reducti ons:   Table 11: Total Pollutant Reductions per m3 Beer Produced, by Flue Gas Strategy Pollutant Output (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  25.96  Carbon Monox ide (CO)  1.18 x 10 - 2  Nitrogen Ox ides (NO x )  2.65 x 10- 2  Sulfur  Ox ides (SO x )  5.45 x 10- 2  Hyd roca rbon Particulates  5.7 7 x 10 - 2  Mercur y  3.33x 10 - 7             20   4.3 Summary of Environmental Benefits (Pollution Reductions)   To summ ariz e the result s detailed in Secti ons 4. 1 and 4.2, the following poll utants are gen erat ed b y a t ypical b r ewer y, on a per m 3  bee r produced basis :   Table 12: Total Pollutants Generated per m3 Beer Produced Pollutant Output (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  40.62  Carbon Monox ide (CO)  1.84x 10 - 2  Nitrogen Ox ides (NO x )  4.15x 10- 2  Sulfur  Ox ides (SO x )  8.51x 10- 2  Hyd roca rbon Particulates  9.19 x 10 - 2  Mercur y  5.21 x 10 - 7    The tot al poll utant redu c ti ons are summ ed from each strat e g y, and combi ned to ar rive at the foll owing numbe rs:   Table 13: Total Pollutants Reduction Achieved by Heat Integration and Flue Gas Recovery Pollutant Output (kg pollutant/m3 beer) C arbon Diox ide (CO 2 )  36.12  Carbon Monox ide (CO)  1.64 x 10 - 2  Nitrogen Ox ides (NO x )  3.69 x 10- 2  Sulfur  Ox ides (SO x )  7.58 x 10- 2  Hyd roca rbon Particulates  8.18 x 10 - 2  Mercur y  4.63 x 10 - 7    This is approx im atel y an 89%  redu cti on in ever y gr eenhouse gas, as well as hyd roca rbon particulates and mer cur y. Although the esti mates here ar e ma gnit ude - of - o rder (i.e. an accu rac y of ±50%), these result s illust rate the huge enviro nmental incenti ves of th e heat int e gr ati on and flue gas recove r y strate gi es.   21   4.4 Other environmental impacts              Deposi ti on of organic matte r is freque ntl y en counter ed in equ ipm ent such as wate r coolers, condens ers, and cooli ng towers. The mos t widespread miti gati on strate g y du ring onli ne operati on as well as offli ne cleanin g of heat ex ch angers is the use of che mi cal agents containin g subst ances that ar e poten ti all y harmful to the envi ronment. For ex ampl e, anti - scalants, and anti -fouling agents ar e bro a dl y used in desali nati o n and ch emi cal plants . The y usuall y contain  addit ives include chemi c als like pol yphosphate, chlorine, hypo chlorit e, co agul ants, etc . The use of anti - scali n g ch emi cal s must be just ified in the plant by th e frequen c y and sev erit y of the fouling. Fo r ex ampl e, if fouli ng occ u rs infrequ entl y and not si gnificantl y, as it would in a typic al brewe r y, the use of thes e ch emi cals ma y be red uced or replac ed enti r el y by mech anical means (such as sim pl y cleanin g by hand). The fin al deci sion on whether these ch emi cals are used will depe nd on th e final pl ant design, as well as th e ad equac y of ch emi cal disp osal methods avail abl e at the sit e.               22   5.0 Social Implications  In ord er to assess the so cial impact of the afore mentioned heat recover y strate gies, we focused on sever al facto rs. These include: the possi bil it y of job creati on, promot ion of student learnin g, and their viabili t y for s ett ing an ex ampl e for sust ainable desi gn. At first the rea cti on of the local comm unit y doe s seem to be a vali d four th factor for assessing th e social impli cati on of the waste he at recover y strate gies. It was decid ed, howeve r, that the i mpl ementati on of these strate gies will not be apparent to the gen eral publi c, thus the social impact in that regard will be minim al.   5.1 Job creation The implemen tation of both the Heat Inte gr ati on  and Flue Gas Het Recov er y strat e gies will require the inst all ation of new machiner y i nto the brewer y. Since the brewe r y will be in operati on alm ost all the time, regula r maintenanc e checks ar e requir ed to ensure the mach ines sta y in an op er able state. Whil e the bre wer y on it s own alr ead y requir es regul ar mainten anc e to keep it runnin g, it is advisable to hire new m embers for th e ex ist ing maintenance crew to maintain machines need ed to implement the aforementioned waste he a t recover y strat e gies. Hiring mor e people is the opti mal solut ion to ensure efficien c y and accura c y in the regul ar maintenance checks fo r the new machines. At th e same time, ener g y sav ings gene rated b y the implementation of the aforementioned waste he at r ecover y str ate gies will help make hiring new maintenance crew mem bers for the br ewer y afford able. Thus it is safe to sa y that the implementation of the aforem enti oned waste heat recove r y strate gies will create some job opportuni ti es in the operati on of the  brew er y.   Should the implementation of the HEN and/o r Fl ue Gas heat recov er y m ethod prove to produce  posi ti ve effe cts for UBC, thi s might en c oura ge sim il ar designs t o be implemented in future const ructi on proje cts both withi n and outsi de of UBC. This will  lea d to an in cre ase in the demand for the machine r y ne eded fo r the implementation of these strategi es. Fa ced with the increas ed demand, ex ist ing manu factur ers of will need to ex pand their sco pe of ope rati on. At the same time new compani es might be created  in an attempt to “cash in” on the increased demand for these ma chines. The various competit ors the n, in an att empt to produce more revenu e for 23   their companies, will att empt to develop new pr oducts or perhaps new manufacturin g methods. In an y cas e, as lon g  as ther e is an inc reas ed demand fo r the m achiner y used in the implementation of the aforementioned waste he at In both cases, new job opportuni ti es will be creat ed.   5.2 Student Learning W it h  UBC acti ng as a pioneer b y tr yin g out diff er ent methods to achieve a sust ainable lifest yle, it is important to encoura ge students to be mindful of the ef fects t heir acti ons can have on the world around the m. As s t ated befor e, the impl ementati on of waste heat recover y str ate gies is not immediatel y obvio us to the pu bli c. Howeve r, the implementation of such strate g y can help promot e the idea of susta inable design to students in certain areas o f stud y, such as mech anical engin eerin g. B y off erin g educati onal tours, wh ere students are given an ov e rview of the waste heat recover y s ystem, stu dents can gain an und erst anding of what it means by sust ainable design. This can also spark inte re sts in some students to learn more on sust ainabili t y, and perhaps pu rsue a car ee r in the appli cati o n of sustainable desi gn in the future. The re is no reason to limi t the target audien ce fo r the af orementioned tours to just students in UBC. The tours shoul d also be offer ed outs ide of UBC, to spread the ide a of susta inable design. The ide as presented are perhaps a litt le unreali sti c to be put int o practi ce. It is to be noted, howev er, that th ere is an educati onal value in show casin g the waste heat recov er y s yste m of the brew er y. Aft er all , it is much bett er to give an actu al ex ampl e of a workin g appli c ati on of sust ainable desi gn. It wil l be mu ch easier fo r student to understand the s ystem and provide a much stronger vie w point on the benefits in a sust ainable design.   5.3 Possible Case Study B y implementi n g the HEN and/or Flue Gas hea t recover y strat e g y in th e brewe r y, the facil it y can act as a  testin g ground for the viabili t y to appl y sim il ar waste heat recove r y s ystems for future const ructi on pr ojects. If result s are favo rable, new buil dings arou nd the campus shoul d be equipped with he at re cover y s ystems based off the desi gn us ed in the br ewer y. This can aid in UBC’s goal to become more sustainable in running the campus. At the same time, energy savings can help brin g to tal operati onal cost of the campus down to some ex tent.  24   The presented wast e heat recove r y strat e gies ar e more suit ed for produ cti on facil it ies sim il ar to a brewer y. Whil e thi s might cause pro blems for the implementati on of the system to normal buil dings, ther e are produ cti on facil it ies out there that can benefit from the implementation of such s ystem. UBC can publi s h some sort of  an annu al report conc ernin g the operati on of the brew e r y. This report shoul d include the oper ati onal cost, and perh aps a calculated valu e on the ener g y savin gs achi eved by the waste he at reco ver y s yst em. This can give those in cha r ge of producti on facil it ies sim il ar to a brew er y outsi de the campus a rou gh id ea of whether or not the im plementation of such a sys tem can be bene ficial t hem. Once again, if the result s ar e la r gel y posi ti v e, produ cti on facil it ies outsi de the campus ma y start implemented their own  waste heat recover y s ystem.   5.4 Social Impacts: Conclusions Once implemented, the waste heat recove r y s ys tem will not be apparent to the local populace. To give peop le an understandin g on the design and ben efits on implementi ng the s ystem, it is advisabl e for UBC to offer show ca sing tours and/or rele ase annual reports on the operati on of the brewe r y. If the waste he at recov er y s ystem is highl y ben eficial to the operati on of the brewer y, students and those outsi de of campus will become int erested in the sy stem. This newfound int erest can le ad to an ex pansion of the manufactu ring on the machiner y used in the system. This sit uati on ca n cr eate numerous job op portunit ies. At the same t im e, it will encou ra ge the implementation of simi lar s ystems for future const ructi on projects withi n and outsi de of the UBC campus .            25   6.0 Conclusions and Recommendations UBC’s Microbrewery inevitable releases waste heat along with its desired product, beer for UBC students. Accor ding to theo r y stated in literature, 1 m 3  of bee r co sts 1.09 GJ of ener g y and $10.15 to produce. The two strate gies inves ti gated in thi s repo rt, na mel y Heat Inte grati on and Flue Gas Recov er y and Separati on have successfull y achiev ed a  significant  economi c reducti on  ($2.94/m 3  beer)  of beer produ ct ion costs , as well as lower the detrimental environmental ef fects of the brewe r y  (89% pote nti al reducti ons in emi ssi ons) , namel y in the form of gre enhouse gase s and car cinogenic/t ox ic  particulates such as h ydro carbon particul ates and mercu r y . The last it em  of the tripl e - bott om - li ne anal ysis , social ef fe cts, is not apparentl y reali z ed, since these str at egi es are most l y techni ca l in nature.   In ord er to make the efforts of sust ainabili t y more visi ble to students, an arra y of publi cit y ef forts ar e reco mm ended. For ex ampl e, some t ype of logo could be made and stuck on the heat inte gr ati on equipm ent in the brewe r y, so t hat students and work ers who visi t the brewe r y on a regula r basis can be const antl y remi nded of the effort in sust ainabili t y. The Brewer y can also be advertised on the UBC websit e for volunt eers who wish to help conti nue these sust ainable efforts. Fin all y, the bre wer y as a popul ar locati on for social gat herings will inevitabl y draw lar ge cro wds of st uden ts, who will reco gni z e these sust ainable ef fo rts and appl y them in other UBC buil dings.   A final recomm endati on i s the investi gati on of a biogas producti on plant, which uti li z es the waste heat from the spent grains in the brew er y. The more detailed anal ysis in Appendix 3 shows that 58% of the tot al waste heat from the brewe r y  can be recov ered sim pl y b y consi de rin g th e waste grains as a “waste heat” source, since the grains themselves have an extremely high heat content (1 kg of waste gr ains produces 10.6 L of bio gas with ~70% methane, which has a correspondi n g ener g y content of 3.82 MJ ). Ho wever, the CO 2  emissi ons fro m the ana erobic digestors would have t o be evaluated, and bal anced with the natural gas/co al fuel savin gs achieved in the br ewer y to confirm wheth er a net GHG emi ssi on reducti on is achievabl e. Neverthel ess, it is an ex tremel y promisi ng strat e g y worth pursu ing, shoul d t he implementation of waste h eat recove r y strategi es come to life in the UBC Microbre wer y. References  BC H ydro. (2013 ). BC Hydro: Electricity Generation Systems . Retrieved from htt p:/ /www.bch ydro. com/ ener g y - i n - b c/our_s yste m/ gene rati on.htm l   Forti sBC . (2013). Natural Gas Rates and Consumptions in BC for Year 2013 . Retrieved from htt p:/ /www.forti sbc.com/ NaturalGas/ Business/ P riceAndMa rket Info rmati on/P ages/H eat - cont ent -values.aspx   Lau, Anthon y. (2013 ). CHBE 459 Chemical and Biological Engineering Economics . 4 t h - year Chemi cal Engin eerin g C ourse at UBC.   Must er - S lawit sch et al. (2011). The green brewery concept – energy efficiency and the use of renewable energy sources in breweries . Applied Thermal En ginee ring, 31 ( 13), 2123 - 2134 .   Natural gas.or g. (2013). Natural Gas and the Environment – Fossil Fuel Emission Levels . Retrieved from htt p:/ /ww w.natural gas.o r g/environ ment/naturalgas.asp   Seider et al. (2009). Product and Process Design Principles . New Jerse y: J ohn Wil e y and Sons, In c .   United States Environmental Protecti on Agenc y (2001). Air Pollution Control Technology Fact Sheet . Retrieved from htt p:/ /www.epa. gov/t tnchie 1/m kb/documents/ fpack. pdf   Universit y of Washingto n (2005). Energy in Natural Processes and Human Consumption – Some Numbers . Retriev e d from htt p:/ /www.ocean.washin gton.edu/cou rses/envir21 5/ener g ynumbers.pd f   Westerlund et al. (2012). Flue gas purification and heat recovery: A biomass fired boiler supplied with an open absorption system . Applied Ener g y, 96, 444.           Appendices   1   Appendix A: Heat Transfer and Heat Exchanger Sizing Calculations  **Note: Since ac curat e plant data is not avail able, thi s anal ysis is done pur el y on ball park esti mates and aver a ges provided b y reli able proce ss en gineerin g sourc es. Consi dering thi s to be the equivalent stage of a preli mi nar y pro cess pla nt esti mate (where  ini ti al esti mates are known but no design/proc ess de tails are known), th e gro ss esti mate will have an error m ar gin of ±50% (Lau, 2013).   1. Heat Exchanger Area Sizing  For heat exchangers, Q = UA∆T LM , whe re:   U = Overall heat transfe r coefficient; we ass ume all heat transfer int erfa ce s to be water  steel  water. Th ere fore U = 370 W/m 2 *K on avera ge (Se ider et al, 2009).   A = Surface area for he at transfer; the most important paramete r used to siz e heat ex changers. This wil l be the unknown in our calculati ons.   ∆T LM  = Lo g - mean temp e rature dif fer enc e betw een hot and cold str eams. Since we do not poss ess accur ate process data, but know that the pinch t emperatur e diff eren ces are app rox im atel y 10 o C between all streams (Slat witsch et al, 2011), then we assume ∆T LM  to be equal to 10o C .   We can then combine the U and ∆T LM  esti mates and the esti mate of tot al int egr ated heat ener g y of 27,000 GJ / ye ar = 856.2 kW to calcu late the tot al amount of heat ex changer area required. Th ere fore:   A = Q/(U*∆T LM ) = 231.4 m2  = 2,491 ft 2   Cost correlations (Seide r et al, 2009) can be used for siz ing pro cess equip ment. Various equati ons describe the material, pressur e, tube - len gth corr ecti on factor, and bare - modul e cost; all these fa ctors ar e then mu lt ipl ied together to obt ai n a final cost for th e equip ment.  2   Material Factor FM This factor ac counts for the mate rial(s) of const ructi on of the associated pro cess equipm ent. Assumi ng he at ex chan gers to be of t he floati n g head, sh ell - a nd - tube t ype (stainl ess steel on bot h shell and tubes):   F M  = a + b (A/100) = 2.7 0 + 0.07(2,491/100) = 4. 4437   Pressure Factor FP  This factor ac counts for t he ex tra costs incu rred in order to desi gn the proc ess equipm ent to withs tand its t ypical operati n g pressur es. Assum ing the sh ell - side pressure of the heat ex changers to be 2 atm absol ute (14.7 PS IG):   F P  = 0.9803 + 0.018 (P/10 0) + 0.0017 (P/10 0)2  = 0.9803 + 0.018 (14.7/100) + 0.0017 (14.7/100) 2  = 0.9834   Tube-Length Correction Factor FL  This factor corr ects fo r an y ex pansion s (or contracti ons) in t he heat exchanger’s tube length, compar ed to a sta ndard len gth (20 ft). Assumi ng the he at ex chan ge rs used in the brew er y contain 20 - ft tubes, F L = 1 .    Bare-Module Cost CB  The bare - modul e cost corresponds to the raw m aterial costs of the proc ess equipm ent, const ructi on costs , contra ctor fe es and inst all ati on fees. Th e costs ar e stated as USD at year 2006. For a floati ng - head heat ex changer:    C B  = ex p[ a 1  + a 2  ln(A) + a 3  ln2 (A)] = ex p[ 11.2927 -  0.9228ln(2491) + 0.098 61ln 2 (2491)]                    = $24,512 US D     3   Material Factor FM  The material facto r co vers the main mate rial of const ructi on used for the proc ess equipm ent. In our cas e it is assum ed to be Stainless Steel - 316. Therefor e, F M  = 2.1 according to Seider et al (2009).  Equipment Purchase Cost CP  Finall y, C P  is the equipm ent purchase cost. It is the product of all the previ ous discussed factors, as su ch:  C P  = F M F P F L C B  = (2.1)(0.9834 )(1) ($24,5 12 USD)  = $50,621 USD (2006)  = $51,633 CAD (2006)  The Chemi cal En gine eri ng plant ind ex of 2006 is 500. Assumi ng the CE plant index of 2013 is 590:   C P, 201 3  = C P,20 06 *(590/500) = ($51,633 CAD) (590 /500) = $60,927    Therefo re a rou gh cost of the tot al heat ex chan ge r tr ansfer area is $60, 927 CAD, fo r a tot al beer produ cti on rat e of 90,000 m 3 / yea r. This is a capit al cost and will be cheap er, i.e. “spread out more,” the greater the expected lifetime of the brewery. For example, for an expected brewe r y lifeti me of 10 or 20 years:   Lif eti me of 10 yea rs: HE X Cost / yea r = ($60,927/1 0 ye ars)/(90,000 m 3 / ye ar ) = $0.677 / m 3  beer  Lif eti me of 20 yea rs: HE X Cost / yea r = ($60,927/2 0 ye ars)/(90,000 m 3 / ye ar ) = $0.338/m 3  beer          4   Appendix B: Flue Gas Absorber Cost Calculations  Using information Seider et al (2009) and US EPA, $23,000 per standard m3 /sec is the raw capital cost of the packed bed scrubber. We use the formula Q=C*A*(2*g*H*(Ti - To/Ti))^1/2 to find the volumetric flow rate of Flue gas entering the scrubber, where:  Q- Flue Gas flowrate A- Cross sectional area of the scrubber(chimney) – Assumed to be 5 m2 for an industrial brewery C - Discharge coefficient (0.65 - 0.70) g-  gravitational acceleration (9.8m/s^2) H- height of the scrubber – Assumed to be 3m for an industrial brewery Ti - average temperature of the flue gas – Assumed to be 500K To- average outside temperature in Vancouver   Substituting in the appropriate numbers lead to operating and maintenance costs of $0.67/m3 of beer produced and a capital cost of $0.49/m3 beer produced. Assuming that natural gas costs has an energy content of 37.26 MJ/m3, a BC cost of $0.105 m3/GJ, and that 0.28 GJ/m3 beer is the energy savings achieved by the flue gas recovery strategy, $0.79/m3 beer is the savings. Therefore, the net cost of the flue gas scrubber system is $0.37/m3 beer produced.  The results:  Capital cost:$0.49/m3 beer produced  Operating/maintenance costs: $0.67/m3 of beer produced    Extra Cost compared to Normal brewery: $0.37/ m3 beer produced         5   Appendix C: Potential Biogas Production from Waste Grain   Breweries produ ce massi ve amount s of waste cer eal grain, afte r all suga rs are ex tracted from the wort for ferm e ntation. This waste grain was tradit ionall y dumpe d int o landfil ls, but a more sust ainable alt erna ti ve has been developed to convert these grains to livestock feed for farms. An even mor e s ustainable alternative is proposed here, where the “heat content” of grains is ex tracted b y conve rting th e waste gr ains int o biogas, a mix ture compris ed of most l y M ethane (CH 4 ) gas, along with CO 2 , N 2 , and O 2 .   In the bio gas produ cti on process, the sludg e - li ke waste grain mix ture under goes an elaborate sc reenin g and fil tering process whe re la rge particles (such as debris) are removed. The remaining biom ass ente r s a lar ge an aerobi c di ges ter, whe re the sludg e is fermented for a period of 35~70 da ys (Babel et  al, 2009), kil li ng off most pathogens an d fecal coli fo rms. An indus triall y - siz ed di geste r is usuall y in th e ord er of 4m - diamete r b y 11m - h eight, as shown in the following picture; obvious l y, the digestor for the Microbrewe r y will be much small er than thi s.  Typic all y 1 kg of brew e r y slud ge can produce 10.6 L of bio gas mix ture (wit h 69% CH4 , 26 % CO 2 , 1% O 2 , and 4% N 2 ) with an ener g y cont en t of 360 MJ /m3 . The final stage of the bio gas producti on invol ves the separati on of gas from remaining soli d wastes in a de cant er. Ana erobic digestors o ffe r the adv antage of well - seal ed vessel, which means that v er y li tt le gas eous emi ssi on will leak out and cause a tox ic/offensive odour to the surroundin g environ ment. Also, the slud ge rec ycl e rati o is high (40~ 50%), meanin g th at waste grains can be “re - used” multiple times before the y are compl etel y stripped of their bio gas potent ial.          Figure 7: Typical Industrial Anaerobic Digestor 6    The amount of brewe r y sludge he avil y dep ends on man y vari ables of the brewer y, such as producti on efficien c y, ener g y use, and plant de sign. Accordin g to th e work of Slawit sch et al (2011), a br ewe r y produ cing 90,000 m 3  beer / yr wastes on ave ra ge 15,00 0 tonn es of grain pe r ye a r. This is equivalent to sa yin g that 58% of the tot al waste heat (0.63 GJ /m 3  beer produced) can be recove red b y pro ducing and bu rning bio gas alone, and so it the most efficient ener g y recove r y strate g y.             

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            data-media="{[{embed.selectedMedia}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
https://iiif.library.ubc.ca/presentation/dsp.18861.1-0108505/manifest

Comment

Related Items