Design and analysis of biorefineries bad on raw glycerol:Addressing the glycerol problem
John A.Posada,Luis E.Rincón,Carlos A.Cardona ⇑
Instituto de Biotecnología y Agroindustria,Departamento de Ingeniería Química,Universidad Nacional de Colombia de Manizales,Cra.27No.64-60,Manizales,Colombia
a r t i c l e i n f o Article history:
Received 7October 2011
Received in revid form 20January 2012Accepted 25January 2012
Available online 6February 2012Keywords:
Glycerol conversion Process design Process simulation Process asssment皮肤干燥的原因
Glycerol-bad biorefineries
a b s t r a c t
Glycerol as a low-cost by-product of the biodiel industry can be considered a renewable building block for biorefineries.In this work,the conversion of raw glycerol to nine added-value products obtained by chemical (syn-gas,acrolein,and 1,2-propanediol)or bio-chemical (ethanol,1,3-propanediol,D -lactic acid,succinic acid,propionic acid,and poly-3-hydroxybutyrate)routes were considered.The technological schemes for the synthesis routes were designed,simulated,and economically assd using Aspen Plus and Aspen Icarus Process Evaluator,respectively.The techno-economic potential of a glycerol-bad biorefinery system for the production of fuels,chemicals,and plastics was analyzed using the commercial Commercial Sale Price /Production Cost ratio criteria,under different production scenarios.More income can be earned from 1,3-propane
diol and 1,2-propanediol production,while less income would be obtained from hydrogen and succinic acid.This analysis may be uful mainly for biodiel producers since veral profitable alternatives are prented and discusd.英语四六级作文模板
Ó2012Elvier Ltd.All rights rerved.
1.Introduction
A key aspect of the manufacture of biodiel is the co-produc-tion of glycerol,which is obtained at a
weight ratio of 1/10(glyc-erol/biodiel).Currently,glycerol does no longer reprent a significant benefit for the biodiel industry due to its low price as conquence of the growing market of biodiel.For example,glycerol production incread 400%between 2004and 2006,and its price fell nearly 10-fold (Posada and Cardona,2010a ).Therefore,economic exploitation of glycerol as raw material for its transfor-mation to added-value products ems economically necessary.In the prent study,the production of nine added-value products from glycerol by chemical or biochemical conversion routes were analyzed bad on techno-economic criteria.In addition,different reaction conditions,strains and downstream process were con-sidered.The results obtained may be especially uful for biodiel producers since veral profitable transformations of raw glycerol into
added-value products are prented and discusd.2.Chemical conversion of glycerol
Glycerol can be transformed to added-value products by oxidation,reduction,decomposition,gasification and pyrolysis.For example,the main oxygenated products from glycerol are gly-ceric acid,dihydroxyacetone,hydroxypyruvic acid,tartaric acid,mesoxalic acid and oxalic acid,besides some intermediates (e.g.,glyceraldehyde,glycolic acid,and glyoxylic acid)(Posada,2011).Oxidation reactions have mostly been studied using palladium,platinum and gold as catalysts,but palladium and platinum are deactivated with the increment of the reaction time (Demirel-Gülen et al.,2005).Better catalytic performances have been achieved with platinum and gold catalysts incorporating promoters (e.g.,lead and bismuth)to improve the oxidation of condary alcohols and to avoid the products degradation (Garcia et al.,1995).Glycerol reduc-tion mainly generates 1,2-propylene glycol,1,3-propylene glycol,ethylene glycol,and other by-products (e.g.,lactic acid,acetol,acro-leine)besides the degradation products (e.g.,propanol,methanol,methane,and carbon dioxide)(Dasari et al.,2005a ).This reaction us different catalysts such as copper,zinc,ruthenium,cobalt,magnesium,molybdenum,nickel,palladium and platinum (Lahr and Shanks,2005),and a wide range of pressures (2000–5000psi)and temperatures (200–350°C)have been reported (Casale and Go-mez,1994).However,the highest le
ctivities to propylene glycol (the most important reduction product)have been reported for cup-per-bad catalysts,which also exhibit low lectivities for ethylene glycol and other degradation by-products (Dasari et al.,2005b ).Gasification of glycerol consists of a thermochemical degrada-tion process in the prence of gasification agents (i.e.,air,pure oxygen or steam)that produces syngas (main product)(Ahmed et al.,2011).Syngas is a mixture of hydrogen and carbon monoxide as main products,but methane,carbon dioxide and other residues (e.g.,tar,char and ash)are also generated.A wide range of conver-sions and lectivities have been reported depending not only on the operational conditions such as temperature,pressure and glyc-erol concentration,but also on the pollutants prence into the raw
0960-8524/$-e front matter Ó2012Elvier Ltd.All rights rerved.doi:10.1016/j.biortech.2012.01.151
Corresponding author.Tel.:+5768879300x50199;fax:+5768879300x50452.
E-mail address:ccardonaal@ (C.A.Cardona).
flow diagrams for raw glycerol purification((a)purification up to88and98wt.%,and(b)purification up to99.7wt.%)and study cas I–III glycerol((c)dehydration of glycerol,(d)steam gasification of glycerol,(e)hydrogenolysis of glycerol).E,Evaporation column,R:Reactor,Cen: Distillation Column,IER:Ionic Exchange Resin,HE:Heat Exchanger,H:Heater,Con:Condenr,D:Divisor,M:Mixer,Comp:Compressor,Sep:
广州美术培训glycerol by a number of bacteria,Bacillus megaterium and Cupriavidus necator being the most important ones(Cavalheiro et al.,2009;Pablo et al.,2008;Posada et al.,2011b).D-Lactic acid production from glycerol using li strains was re-cently reported(Mazumdar et al.,2010)and analyzed(Posada et al.,2011a).Fermentative production of succinic acid from glyc-erol has been achieved using Actinobacillus succinogenes and re-combinant E.coli(Blankschien et al.,2010),although the production of ,acetic acid,formic acid,lactic acid, and ethanol)limits the possibility of scaling up this process to an industrial level since a more complex downstream processing would be required(Kim et al.,2004).Finally,propionic acid can be produced by propionibacteria via the dicarboxylic acid pathway with acetic acid and succinic acid as by-products(Coral et al.,2008; Zhang and Yang,2009).
4.Methodology
Initially,13chemical routes and nine fermentative products were identified as possible transformation ways for glycerol conversion to added-value products.Bad on technical,economic and environ-mental ,temperature and pressure of reaction,levels of conversion/lectivity/productivity,requirements of energy,price and market of the main product and wastes production),three chemical and six fermentative products were chon to be analyzed. The process design followed a previously described strategy(Car-dona and Sánchez,2007;Quintero et al.,2008)which combines the hierarchical decomposition methodology with the process design method known as breadth-first.This strategy allows systematic gen-eration of alternatives that consider specific characteristics of each process and simultaneous comparison of different process alterna-tives.In this way,it is possible to screen different process alterna-tives and to evaluate them at the next level of the hierarchical decomposition using process simulators.Therefore,the process sim-ulator Aspen Plus(Aspen Technology,Inc.,USA)was ud for defin-ing,structuring,specifying,and simulating the technological schemes for either chemical or biochemical conversion of glycerol to added-value components.The most complex and detailed techno-logical schemes were obtained by means of rigorous simulations, which involved nsitivity analys and arch of optimal operation conditions.Since not only pure,but also raw glycerol has been ud as feedstock,a typical composition of a glycerol-rich stream ob-tained during the biodiel production from IdaGold mustar
d (Thompson and He,2006)was considered as the feedstock.Since this raw glycerol stream contains low concentration of glycerol,a purifi-cation process was analyzed in order to obtain the three most impor-tant qualities of commercially available glycerol(crude glycerol at 88wt.%,technical glycerol at98wt.%and USP glycerol at 99.7wt.%).In addition,specific compounds not available on the As-pen Plus ,free fatty acids,alkyl esters,proteins,salts, cell mass strains,enzymes and other complex molecules produced by reactive-extractive process)were incorporated to the databa for each simulation.For components and properties not included in the Aspen Plus databa,subroutines and special software were de-signed to predict the component properties needed for simulation. For conventional molecules,the group contribution method was ud,while biomass and enzyme were considered as solids and non-conventional compounds,respectively.All results from software cal-culations are prented using an accuracy value of0.01(0.0001is ud recurrently for comparison purpos in some cas).
The reactive systems were analyzed as follows.For the highly exothermic dehydration of glycerol to acrolein,an acid catalyzed process was considered and the reaction scheme reported by Tsukuda et al.,(2007)was ud.The gasification process of glycerol was modeled according to the molar distribution of the reaction products reported by(Mozaffarian et al.,2004).A two-steps pro-cess for the
lective production of1,2-propanediol from glycerol was developed according to the model propod by Akiyama et al.(2009).Subquently,for biochemical conversion of glycerol (i.e.,glycerol fermentation),six main products were considered. Also,it is important to note that,although veral possibilities for glycerol fermentation to added-value products have been re-ported,just a few publications describe accurate kinetic models. Conquently,for the production of ethanol,poly-3-hydroxybuty-rate,lactic acid,succinic acid and propionic acid,a yield approach was ud.Moreover,a stoichiometric approach was considered as a valid and relevant approach for analyzing the reaction stage of different technological schemes.
With respect to the economic asssment,capital and operating costs were calculated using the software,Aspen Icarus Process Evaluator(Aspen Technologies,Inc.,USA).The economic parame-ters considered were tho from Colombia,in US dollars for a10-year period at an annual interest rate of16%,considering the straight line depreciation method with a33%income tax(Posada et al.,2010).The Colombian labor cost ud for operatives and supervisors was US$2.14/h and US$4.29/h,respectively.Also,the prices ud for electricity,water and low pressure vapor were US$0.03044/kWh,US$1.252/m3and US$8.18/ton,respectively. 5.Results and discussions
Since the feedstock for all the process is a raw glycerol stream obtained from a typical biodiel pl
ant,thefirst step of consider-ation was purification.Fig.1a.shows the simplifiedflowsheet for raw glycerol purification to obtain88wt.%(crude glycerol)and 98wt.%(technical glycerol).Production of glycerol at99.7wt.% (glycerol USP grade)required a further refining process using an ion exchange resin which removes the triglycerides still contained in the mixture,as shown in Fig.1b(Posada and Cardona,2010b).In addition to the purification analysis,two different scenarios were considered due to the high concentration of methanol(32.6wt.%) in the glycerol stream.In thefirst scenario,the methanol obtained during the evaporation stage was considered as a waste,while in the cond scenario this stream was recycled and reud for transterification to produce biodiel(methanol at99wt.%).In other words,methanol was considered as a by-product with an economical value in the last scenario.Therefore,the purification costs of raw glycerol up to88wt.%were0.1574US$/L(scenario I)and0.0984US$/L(scenario II),and up to98wt.%were0.1782 Table1
Composition of fed raw glycerol,massflow of purified glycerol and purification costs.
soldMaterials(kg/h)Massflow(kg/h) Raw glycerol(triglycerides2%,methanol32.59%,
glycerol60.05%,NaOCH32.62%,
proteins0.13%,fats1.94%)(wt.%)
973.30
Products Massflow(kg/h) Methanol301.98
Glycerol at88%(option1)665.25
Glycerol at98%(option2)596.60
Glycerol at99.7%(option3)586.18
Purification costs-Scenario I*(US$/L)
Glycerol at88%0.22
Glycerol at98%0.26
Glycerol at99.7%0.35
Purification costs-Scenario II**(US$/L)
Glycerol at88%0.16
Glycerol at98%0.20
Glycerol at99.7%0.28
*Scenario I:Methanol is considered as a waste.
**Scenario II:Methanol is considered as a purification by-product with economic value.
284J.A.Posada et al./Bioresource Technology111(2012)282–293
US$/L(scenario I)and0.1124US$/L(scenario II).It is important to note that the purification costs were always lower than their commercial Commercial Sale Price s.In addition,when anhydrous methanol at99wt.%is recovered,a reduction of19–26%in the purification costs was obtained.The economic results showed that the purification process were profitable for all glycerol grades (Table1).
5.1.Glycerol purification
Since the feedstock for all the process is a raw glycerol stream obtained from a typical biodiel plant,thefirst step of consider-ation was purification.Fig.1a shows the simplifiedflowsheet for raw glyc
erol purification to obtain88wt.%(crude glycerol)and 98wt.%(technical glycerol).Production of glycerol at99.7wt.% (glycerol USP grade)required a further refining process using an ion exchange resin which removes the triglycerides still contained in the mixture,as shown in Fig.1b(Posada and Cardona,2010b).In addition to the purification analysis,two different scenarios were considered due to the high concentration of methanol(32.6wt.%) in the glycerol stream.In thefirst scenario,the methanol obtained during the evaporation stage was considered as a waste,while in the cond scenario this stream was recycled and reud for transterification to produce biodiel(methanol at99wt.%).In other words,methanol was considered as a by-product with an economical value in the last scenario.Therefore,the purification costs of raw glycerol up to88wt.%were0.1574US$/L(scenario I)and0.0984US$/L(scenario II),and98wt.%were0.1782US$/L (scenario I)and0.1124US$/L(scenario II).It is important to note that the purification costs were always lower than their commercial Commercial Sale Price s.In addition,when anhydrous methanol at99wt.%is recovered,a reduction of19–26%in the purification costs was obtained.The economic results showed that the purification process were profitable for all glycerol grades (Table1).
5.2.Chemical conversion of glycerol,ca study I–III
For the chemical conversion of glycerol,dehydration,steam gasification,and hydrogenolysis were con
sidered and their respec-tive products were acrolein,hydrogen,and1,2-propanediol.The three options were simulated using the process configuration shown in Fig.1c–e.A glycerol conversion of100%was reached for all process,and the respective molar yields for acrolein, hydrogen,and1,2-propanediol were85.2%,78.2%and79.97% (Table2).In addition,thefirst two process were heat-integrated, recovering175and67W/(feeding kg)for dehydration and gasifica-tion process,respectively.
The results obtained during the economic asssment of the chemical conversion of glycerol are summarized in Fig.2a and b. The ratio,Commercial Sale Price/Total Production Cost,is shown in Fig.2a,while the main contributors to the production costs are shown in Fig.2b.Since the production of acrolein at98.5wt.%re-quires a powerful coolant system,twofinal concentrations were considered and the industrial grade(92wt.%)was also included in this analysis.During the acrolein production at92wt.%,most of the production costs were reprented by raw materials and r-vices(clo to72%of the total production costs).For acrolein pro-duction at98.5wt.%,the rvice contributions were about67%of total production costs.Thus,the production process of acrolein at
Table2
Main process streams and molar yields for cas of study I–IV.Production of acrolein,hydrogen,1,2-propanediol and D-lactic acid from glycerol with different qualities.
Ca study I:
Acrolein II:
Hydrogen
III:1,2-
Propanediol
IV:D-Lactic acid
Scenario(1)Pure glycerol
diluted at20g/l (2)Pure glycerol
diluted at20g/l
(3)Pure glycerol
上海高考英语
diluted at40g/l
(4)Raw glycerol
diluted at40g/l
(5)Raw glycerol
diluted at60g/l
Main reactives
(kg/h)
Raw glycerol at
88wt.%
581581
Pure glycerol at
antismoking
98wt.%
579579579
Glycerol
directly
diluted at
10wt.%
100.0100.0
Water3023,33327,99627,99613,78013,8219041
Hydrogen374,765
Strain LA01(pZSKLMgldA)LA02(pZSglpKglpD)LA02D dld(pZSglpKglpD)LA02D dld(pZSglpKglpD)LA02D dld(pZSglpKglpD) Cell mass72.240.821.428.331.5
Residues(kg/h)10000.0
General
aqueous
residues
9427,53127,53613,30813,3338577
Main products(kg/h)
Acrolein at
98.5wt.%
5.2––
Acrolein at
92wt.%
5.6––
Hydrogen at
91wt.%
1.0–
徘徊的意思Syngas–20.7–
1,2-
Propanediol
at99wt.%
––7997
D-Lactic acid at
99wt.%
420416422442433
Molar yield85.20%78.20%85.00%82.00%81.20%83.30%85.90%93.40%
J.A.Posada et al./Bioresource Technology111(2012)282–293285
high purity was not economically viable.The highest Commercial Sale Price/Total Production Cost ratio was obtained for 1,2-propane-diol (i.e.,1.57)indicating that this compound was able to generate the highest economic return for the chemical conversion of glycerol.
Although raw material cost reprents usually around 50%of the total production costs for chemical process,in the ca of hydrogen production from glycerol the sum of raw material and rvices costs were almost 36%(Fig.2b).In addition,the main investment cost was for process units,where the equipment depreciation value was 45.14%.This amount is explained by the strict and complex equipment requirements due to the extreme operational conditions (i.e.,high temperatures and pressures).5.3.Biochemical conversion of glycerol,ca study IV–IX
5.3.1.Ca study IV–VI:carboxylic acids (D -lactic acid,succinic acid,and propionic acid)
Biochemical production of carboxylic acids from glycerol (i.e.,D -lactic acid,succinic acid,and propionic acid)was performed in a whole technological scheme,compod of glycerol purification,gly
cerol fermentation,and carboxilic acid recovery and purifica-tion.In each ca,five fermentation scenarios were simulated con-sidering different strains,substrate concentrations,fermentation times,and fermentation stages.The general considerations related to the ud strains and the molar yields to each carboxylic acid are prented in Tables 2and 3.
For D -lactic acid production five scenarios using pure (98wt.%)or crude (88wt.%)glycerol were considered.The glycerol con-sumptions were higher than 90%,with fermentation times be-tween 36and 72h.The downstream process for D -lactic acid recovery and purification from the fermentation broth was de-signed bad on a reactive-extraction process using tri-n -octyl-amine and dichloromethane as extractant and active diluent,respectively.The complete flowsheet for D -lactic acid production is shown in Fig.3a.The final production of D -lactic acid was directly related not only to fermentation yield but also to substrate con-sumption.In other words,while the order with respect to yield was:Scenario 5>Scenario 4>Scenario 3>Scenario 1>Scenario 2(Table 3),the order with respect to the D -Lactic acid production was:Scenario 4>Scenario 5>Scenario 3>Scenario 1>Scenario 2(Table 2).The change between Scenarios 5and 4occurred due to incomplete consumption of glycerol during the fermentation in the Scenario 5.
For succinic acid production,glycerol consumption was be-tween 58.5%and 96%using pure glycerol macau是什么意思
(98wt.%).The down-stream process ud a reactive-extraction stage where complex molecules were produced from the fermentation products (i.e.,succinic acid,formic acid and acetic acid).Tri-n -octylamine (TOA)and 1-octanol were ud as extraction and diluent agents,respec-tively.The flowsheet for succinic acid production is shown in Fig.3b.The main simulation results for each scenario are shown in Table 2and significant differences for the final production of succinic acid can be obrved among the five analyzed scenarios.The final production of succinic acid depended mainly on the succinic acid yield.For instance,while the order for succinic acid yield was:Scenario 2<Scenario 1<Scenario 5<Scenario 4<Sce-nario 3(Table 3),the order for succinic acid production was:Sce-nario 2<Scenario 1<Scenario 5<Scenario 3<Scenario 4(Table 3).The switch of Scenarios 3and 4occurred becau the glycerol consumption difference was higher than the succinic acid yield.For propionic acid production,five fermentation scenarios were analyzed (Table 3)and fed conditions were as follows:Scenarios 1,2,3and 5ud pure glycerol at 20,50,and 46,and 41g/L,respec-tively;Scenarios 4ud crude glycerol at 17g/L.For Scenarios 4and 5,a fibrous-bed bioreactor packed with immobilized cells was considered.The fermentation times in each ca were:120,150,280,160,and 104h for Scenarios 1,2,3,4,5,
respectively.
btw
乔布斯英文简介Commercial Sale Price/Production Cost ratio for study cas I–VI ((a)study cas I–III,and (b)study cas IV–VI)and share of product purification costs ((c)study cas IV–VI).
