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Rapport SGC 188Demonstration of Software ApplicationBiogas OptimizerTMat the Händelö Biogas SiteSvenskt Gastekniskt Center – April 2008Kristofer CookBioprocess Control Sweden ABRapport SGC 188 1102-7371 ISRN SGC-R-188-SE
SGC:s FÖRORDFUD-projekt inom Svenskt Gastekniskt Center AB avrapporteras normalti rapporter som är fritt tillgängliga för envar intresserad.SGC svarar för utgivningen av rapporterna medan uppdragstagarna för respektiveprojekt eller rapportförfattarna svarar för rapporternas innehåll. Den som utnyttjareventuella beskrivningar, resultat eller dylikt i rapporterna gör detta helt på egetansvar. Delar av rapport får återges med angivande av källan.En förteckning över hittills utgivna SGC-rapporter finns på SGC:shemsida www.sgc.se.SGC är ett samarbetsorgan för företag verksamma inom energigasområdet. Dessfrämsta uppgift är att samordna och effektivisera intressenternas insatser inomområdena forskning, utveckling och demonstration (FUD).SGC har följande delägare:Svenska Gasföreningen, E.ON Gas Sverige AB, E.ON Sverige AB,Göteborg Energi AB, Lunds Energikoncernen AB (publ) och Öresundskraft AB.Följande parter har gjort det möjligt att genomföra detta utvecklingsprojekt:Statens energimyndighetBioprocess Control Sweden ABSvensk Biogas ABSVENSKT GASTEKNISKT CENTER ABJörgen Held
ContentsSummary . 3Sammanfattning: . 4123BACKGROUND . 51.1KEY OBJECTIVE . 61.2PURPOSE . 61.3GOALS . 61.4GENERAL PROJECT PLAN . 71.5TIME PLAN. 7RESULTS . 82.1SATISFYING PROJECT ACTIVITIES & KEY MILESTONES . 82.2PROJECT RESULTS. 82.1.1Obtaining baseline production information . 82.1.2Demonstration of Biogas OtpimizerTM . 9CONCLUSIONS AND RECOMMENDATIONS . 123.1CONCLUSIONS . 123.2RECOMMENDATIONS . 12APPENDIX 1 – COMPANY INFORMATION . 13APPENDIX 2 – OVERVIEW OF BIOGAS OPTIMIZERTM . 14APPENDIX 3 – HÄNDELÖ BIOGAS PLANT. 152
SummaryThere is a growing interest in the utilisation of process optimisation technologieswithin the biogas industry. This trend is being driven by new and growing marketopportunities as well as an interest to improve the overall profitability ofcommercial biogas processes. Biogas OptimizerTM, developed by BioprocessControl Sweden AB based in Lund, Sweden, represents one such processoptimisation technology, utilising a supervisory and control approach to improveboth biogas production efficiency and process stability.A demonstration project was conducted over a nine month period during 2007 atthe Händelö biogas plant in Norrköping, Sweden, owned and operated by SvenskBiogas AB, to provide an indication of the potential of Biogas OptimizerTM toimprove the competiveness of biogas producers. The demonstration projectattempted to satisfy 3 goals, namely; 1) to obtain baseline production informationregarding the average Organic Loading Rate (OLR) and average BiogasProduction Rate (BPR), 2) to demonstrate that the technology behind BiogasOptimizerTM works under full-scale production conditions, and 3) to verify thatsignificant/notable production efficiency improvements can be achieved utilisingBiogas OptimizerTM when compared to baseline production information, and thatbiogas production can be optimised for maximising the utilisation of reactorcapacity while still leaving a comfortable safety margin so as to avoid reactoroverloading.The collection of baseline production information during three months resulted inan average OLR of 4.0 Kg VS/m3/day and average BPR of 2.6 Nm3/m3/day beingselected as baseline data from which to compare the performance of BiogasOtpimizerTM. The full-scale demonstration of Biogas OptimizerTM was conductedover a 40 day period. During these 40 days, OLR recommendations from BiogasOptimizerTM, and the resulting manual adjustment of the OLR by the plantoperator, resulted in an increase in the average OLR from 4.0 to 4.7 Kg/m3/dayand increase in the average BPR from 2.6 to 3.23 Nm3/m3/day. Thus, afteroperating Biogas OptimizerTM for a period of 40 days, the average BPR increasedby 24%. It should however be emphasized that the effect of Biogas OptimizerTM ishard to completely separate from other factors affecting the methane productionrate, such as a minor change in the substrate composition that occurred during thetrial. Additionally, Biogas OptimizerTM was unable to test the maximumutilisation of reactor capacity due to the limited capacity of the plant upgradingunit and high operational cost resulting from an increase in the feedstock priceduring 2007.3
From the demonstration project, one can conclude that the technology behindBiogas OptimizerTM works under full-scale production conditions, can providenotable process efficiency improvements compared to baseline production data,and thus has the potential to increase the competiveness of biogas producers.Sammanfattning:Det finns ett växande intresse i användandet av processoptimeringstekniker inombiogasbranschen. Denna trend drivs framåt av nya och växandemarknadsmöjligheter såväl som av ett intresse att förbättra lönsamheten förkomersiella biogasprocesser. Biogas OptimizerTM, utvecklad av BioprocessControl Sweden AB som är baserade i Lund, representerar en av dessaprocessoptimeringsteknikerna, då den använder sig av både övervakning ochstyrning för att förbättra både biogasproduktionensprocessens effektivitet ochstabilitet.Ett demonstrationsprojekt har 2007 ägt rum under en niomånadersperiod vidHändelö biogasanläggning i Norrköping som ägs och drivs av Svensk Biogas AB.Projektet syftade till att ge en indikation för vilken potential Biogas OptimizerTMhar för att kunna förbättra biogasproducenternas konkurrensförmåga.Demonstrationsprojektet försökte uppfylla tre olika mål, nämligen att; 1) Etableraen grundnivå (baseline) på produktionen med hänsyn till genomsnittlig OLR(Organic Loading Rate) och genomsnittlig BPR (Biogas Production Rate), 2) attvisa att teknologin Biogas OptimizerTM funergar under fullskaligaproduktionsförhållanden, och 3) att klargöra att betydande/märkbareffektivitetsökningar gällande produktionen kan uppnås genom att användaBiogas OptimizerTM när man jämför ”baseline information”, och attbiogasproduktionen kan optimeras för att maximera nyttjandet avreaktorkapaciteten samtidigt som man fortfarande lämnar en tryggsäkerhetsmarginal för att undvika överbelastning av reaktorn.Insamlandet av “baseline information” under en tremånadersperiod resulterade iatt en genomsnittlig OLR av 4.0 Kg VS/m3/dag och en genomsnittlig BPR på 2.6Nm3/m3/dag valdes som utgångspunkt för att kunna jämföra Biogas OptimizerTMprestationsförmåga. Det fullskaliga testet av Biogas OptimizerTM gjordes under en40dagarsperiod. Under dessa 40 dagar resulterade Biogas OptimizersTM OLRrekommendationer och de efterföljande manuella OLR-justeringarna avbiogasanläggningens övervakare i en ökning av den genomsnittliga OLR från 4.0till 4.7 Kg/m3/dag och i en ökning i genomsnittlig BPR från 2.60 till 3.23Nm3/m3/dag. Slutligen kan konstateras att, efter det att Biogas OptimizerTM varit4
aktivt under en 40dagarsperiod kunde BPR ökas med 24%. Det skall dockpoängteras att effekten från Biogas OptimizerTM är svår att helt separera frånandra faktorer som kan påverka takten för metanproduktion, såsom en mindreförändring in substratsammansättningen som inträffade under vägen. Tilläggasskall att Biogas OptimizerTM inte fick möjligheten att testa den maximalaanvändningen av reaktorns kapacitet pga. en begränsad kapacitet i anläggningensuppgraderingsenhet samt höga driftskostnader, vilka var ett resultat av en ökningav råvarupriserna under 2007.Utifrån demonstrationsprojektet , kan man dra slutsatsen att teknologin bakomBiogas OptimizerTM har potentialen att öka biogasproducentens konkurrenskraft.1BACKGROUNDThe popularity of the anaerobic digestion process, as a source of environmentallyfriendly fuel (biogas) for heating, electricity generation and transportation, hasincreased in recent years. This interest in being driven by, among other things,higher oil prices and legislative developments promoting bio-fuels, as well as thebanning of land-filling of biodegradable waste across Europe.As a result, significant investment, both private and public, has gone into theconstruction of bioreactors for the commercial production of biogas.Unfortunately, the profitability of these investments is in question due to problemswith process instability associated with the anaerobic digestion process, poorreactor performance, low productivity, and slow reactor start-up.There is thus a growing interest in the area of process optimisation, where stepshave already been made in recent years with regards to optimising the feedcomposition as well as more efficient digestion technologies, pre-treatmentapproaches and process configurations.Process optimisation can also be facilitated through using supervisory and controlsoftware applications that automatically adjust the loading of feedstock tomaximise the production of biogas, and protect the reactor from overload anddisturbances. It is in this area that a demonstration project was carried out tooverify a software application developed by Bioprocess Control Sweden AB(Appendix 1), based in Lund, Sweden, called Biogas OptimizerTM(Appendix 2),under full-scale production conditions at the Händelö Biogas Site in Norrköping,Sweden (Appendix 3), owned and operated by Svensk Biogas AB (Appendix 1).5
1.1KEY OBJECTIVEThis project thus set out to satisfy the following key objective:To help increase the competitiveness of biogas producers.This key objective was anticipated to be achieved through the following benefitsresulting from using Biogas OptimizerTM: 1.2Less process disturbances and production downtimeAn accelerated and increased production of biogas at existing productionfacilitiesLower investment costs at new production facilities, by using smallerdigesters operating more efficiently.PURPOSEOne critical step on route to introducing a problem free commercial softwareapplication for optimising the commercial production of biogas through improvedprocess control is to demonstrate the software application under full-scale scalecommercial conditions. This project had thus the following purpose: 1.3To provide a demonstration of the first commercially adapted version ofthe supervisory and control application Biogas OptimizerTM on a full-scalecommercial bioreactor.GOALSIn order to satisfy the above purpose, this project set out to fulfil the followinggoals:1. Obtain baseline production information at a full scale production facilitythat can be used to compare key production parameters before and afterthe introduction of Biogas OptimizerTM.2. Demonstrate that the first commercially adapted version of BiogasOptimizerTM does work under full-scale production conditions, and willprovide benefits for other full-scale commercial biogas producers. Thiswill be accomplished by having an operator manually adjust systemparameters based on recommendations from the software application.3. To verify that significant/notable production efficiency improvements canbe achieved by comparing new and baseline production information, andfurther demonstrate that biogas production can be optimised for6
maximising the utilisation of reactor capacity while still leaving acomfortable safety margin so as to avoid reactor overloading.1.4GENERAL PROJECT PLANThe demonstration project was carried out in the following three phases over anine month period:1. Preparation of site and adaptation of software application2. Assessment of baseline production information at full-scale facility anddemonstration of Biogas OptimizerTM along with the verification of results3. Analysis of information and reporting of results1.5TIME PLANThe project was carried between April 2007 and December 2007. Below is anoverview of the project time-plan including project related activities and keymilestones for the demonstration project (see table 1.1).Table 1.1. Time Plan for Demonstration ProjectMonthProject ActivitiesKey Milestones1Preparation of site / adaptationof Biogas OptimizerTM2Preparation of site / adaptation& Biogas OptimizerTM 3Preparation of site / adaptation& Biogas OptimizerTM 4On-site demonstration 5,6On-site demonstration7On-site demonstration8On-site demonstration9Analysis and reporting7Installation of sensors, pumps,and controller to the full-scaledigesterFinal customisation of controlsoftware to existing digesterand SCADA systemAssessment of baselineproduction information Operational test and assessmentof application performance. Data analysis and evaluation ofcontrol performance
2RESULTS2.1SATISFYING PROJECT ACTIVITIES & KEY MILESTONESAfter a 3 month delay with regards to the start of the project, according to theoriginal project plan, the demonstration project was completed within theprojected 9 month time-plan. Each of the Project Activities and Key Milestonesdescribed in section 1.5 were completed during month specified in the time-plan.2.2PROJECT RESULTS2.1.1Obtaining baseline production informationBaseline production information was collected between the 22nd of July and the10th of September 2007 (see figure 2.1). Although the process was not entirelystable during the time allocated to collect baseline production data, the datacollected revealed that the average Organic Loading Rate (OLR) did not exceed 4kg VS/m3/day, and average Biogas Production Rate (BPR) did not exceed 2.5Nm3/m3/day. In order to be conservative, it was thus decided to select an OLR of4.0 kg VS/m3/day and BPR of 2.6 Nm3/m3/day as baseline production figures forcomparative purposes before the installation of Biogas OptimizerTM. It shouldhowever be noted that the operator felt that the baseline figures might notrepresent the maximum potential of the production system, as predicated by priorlaboratory tests.Figure 2.1 Baseline Monitoring of Händelö plant (July 22nd – Sept 12th, 2,00,81,50,5Organic loading rate (OLR)Biogas production rateAverage biogas production rate1,00,50,30,00,00(July 22) 510(Aug 1)15202530(Aug 11)35(Aug 21)Operational Time (Days)84045(Aug 31)5055(Sept 10)Biogas production rate (Nm3/m3, day)Organic Loading rate (Kg VS/m3, day)5,5
2.1.2Demonstration of Biogas OtpimizerTMThe full-scale demonstration and verification of Biogas OptimizerTM wasconducted between the 20th of September and 10th of November 20075,04,54,54,0Biogas production rate (Nm3/m3,day)Organic Loading rate (Kg VS/m3,day)Figure 2.2 Demonstration of Biogas OptimizerTM, Händelö plant (September 20th– November 10th, 2007)4,03,53,53,03,02,52,52,02,0Organic loading rate (OLR)1,5Recommended OLR1,0Biogas production rate1,00,5Average biogas productionrate0,51,50,00,0051015202530Operational Time (days)35404550Note: during day 9-10, the sharp increase in biogas production was due to a minorchange in the feedstock composition.The data set provided from the demonstration of Biogas OptimizerTM can bedivided into four phases as follows:1. The Trial Phase (Sept. 20th – Oct. 1st):The initial OLR at the plant was 3.52 Kg VS/m3/day with an average BPRof 1.96 Nm3/m3/day. As this was a trial phase, the plant operator did notfollow the recommendation provided by Biogas OptimizerTM.2. Full-Scale Testing Phase (Oct 1st – Oct. 19th):During this period, Biogas OptimizerTM provided increasing OLRrecommendations from 4.0 to 4.7 Kg VS/m3/day. The operator followedthe recommendations up to 4.5 Kg VS/m3/day. During this period (threeweeks), the average BPR increased from 2.61 to 3.06 Nm3/m3/day.9
3. Adjusting Period for Plant (Oct. 20th – Nov. 6th):The operator was not able to follow the recommendations provided byBiogas OptimizerTM due to the limitation of the gas upgrading unit.4. Continuation of Full-Scale Testing (Nov. 6th- Nov. 10th):After some modifications to the upgrading unit, the demonstration projectcontinued. The operator started to follow the recommendations providedby Biogas OptimizerTM increasing the OLR from 4.5 to 4.7 Kg VS/m3/day.During this period the average BPR increased from 3.14 to 3.23Nm3/m3/day.The decision was made in the middle of November to stop increasing the OLRdue to capacity limitations of the gas upgrading unit and the high cost of thewheat based stillage substrate used in the process. Biogas OptimizerTM is howeverstill operating and continuing to provide process recommendations to the operator.2.1.3Interpretation of ResultsAfter operating Biogas OptimizerTM for a period of about 40 days, the averageBPR increased from 2.61 to 3.23 Nm3/m3/day, an increase of 24% (see figure 2.3).Figure 2.3 Full-scale operation of Händelö plant (July 20th – November 10th,2007)93,93,783,4Organic loading rate (Kg VS/m3, day)2,92,762,42,251,941,7Organic loading rate(OLR)Recommended OLR31,41,20,92Biogas productionrateAverage biogasproduction rate10,7Biogas production rate (Nm3/m3, day)3,2Start testing nal time (days)108090100110
In terms of satisfying the goals of the project, the results from the demonstrationproject indicate the following:1. Obtaining Baseline Production Information:Reliable baseline production information was obtained during the timeallocated to collect such data. Conservative estimates of both baselineOLR and the average BPR were established in order to compareproduction parameters before and after the installation of BiogasOptimizerTM.2. Successful Verification of Biogas OptimizerTM:A series of OLR recommendations from Biogas OptimizerTM during the 40day demonstration period and resulting increases in the average BPR overthe same period after manual OLR adjustments, indicate that theapplication does work under full-scale production conditions and canprovide benefits for biogas producers.3. Verification of Efficiency Improvements:The 24% increase in the average BPR over the 40 day demonstrationperiod both verifies that Biogas OptimizerTM is capable of providingnotable efficiency improvements to commercial biogas producers.4. Maximum Utilisation of Reactor Capacity:Due to limitations with the capacity of the upgrading unit and high cost ofthe wheat-containing feedstock, the demonstration project was unableverify that by utilising Biogas OptimizerTM biogas production could beoptimised for the maximum utilisation of reactor capacity while stillleaving a comfortable safety margin so as to avoid reactor overloading.11
3CONCLUSIONS AND RECOMMENDATIONS3.1CONCLUSIONSOne can conclude from the demonstration project that Biogas OptimizerTM is ableto provide notable benefits to biogas producers, even though the full extent ofwhat level of process optimisation that can be achieved by using BiogasOptimizerTM is still unexplored. Thus, while still not knowing the upper limit ofthe potential value that can be derived from using Biogas OptimizerTM, one canconclude from this demonstration project that Biogas OptimizerTM has a strongpotential to increase the competiveness of biogas producers. This will beachieved, as previously mentioned, through an accelerated and increasedproduction of biogas, less process disturbances, and a reduction in investmentcosts at new production facilities through utilising smaller more efficientdigesters.3.2RECOMMENDATIONSThis demonstration project served to verify that the technology behind BiogasOptimizerTM works under full-scale production conditions, and that BiogasOptimizerTM can provide notable production efficiency improvements. There ishowever still room for further work to be carried out to explore what can beachieved by using Biogas OptimizerTM. Several recommendations include thefollowing:1. Testing Biogas OptimizerTM during the reactor start-up phase, as well asduring conditions of severe process disturbances.2. Developing and testing an automatic version of Biogas OptimizerTM, toassess the difference between manual and fully/semi automatic monitoringand control of a bioreactor.3. Testing Biogas OptimizerTM with different substrate materials and processconfigurations.12
APPENDIX 1 – COMPANY INFORMATIONBioprocess Control Sweden ABBased:Lund, SwedenStarted:2006Ownership:PrivateBusiness idea: Develop, market, and support process adapted supervisory andcontrol applications that optimise the production of biogas.Svensk Biogas ABBased:Linköping, SwedenStarted:1996 (original company)Ownership:100% owned daughter company to Tekniska Verkin i LinköpingAB (publ)Business idea: Develop the biogas vehicle fuel market by establishing publicfilling stations for biogas on a regional basis, and offering processand production development knowledge.13
APPENDIX 2 – OVERVIEW OF BIOGAS OPTIMIZERTMBiogas OptimizerTM is an award winning process optimisation applicationdesigned to accelerate the biogas production process and ensure greater processstability (see figure A.1).Figure A.1 Graphic depiction of Biogas OptimizerTMBiogas OptimizerTM provides biogas producers with a system for on-linemonitoring and intelligent supervisory control of biogas digesters. The system hasthe ability to protect a biogas production process from overload, while allowingthe maximum utilisation of digester capacity.Biogas OptimizerTM provides biogas producers with the following features: System for on-line monitoring allowing for either manual, automatic orintelligent supervisory and control of bio-reactors.Fast reacting system based on simple commercially available sensors.Ability to protect the system from overload and reject disturbances.Allows for bioreactors to operate close to maximum capacity while stillhaving safety margins for a reliable operation.Compatible with different process configurations, feedstock mixes, andprocess control systems.Biogas OptimizerTM provides biogas producers with the following advantages: An accelerated production process with improved reactor performance.Significantly higher productivity and biogas output.More stable and reliable biogas production process.Protection against process disturbances.Faster start-up of bioreactors.14
APPENDIX 3 – HÄNDELÖ BIOGAS PLANTThe Händelö Biogas Plant is fully owned and operated by Svensk Biogas AB andis located in Norrköping, Sweden. The plant is Sweden’s first crop gas plant andwas completed in December of 2006. The plant is designed to treat 24 000 tons ofsubstrate per year, of which 90% is stillage from a nearby ethanol plant ownedand operated by Agroethanol AB. There are plans to expand the plant to treat 48000 tons of substrate per year to meet a growing market demand for bio-methanein the Norrköping area and Stockholm region.Plant / Process CharacteristicsThe Händelö Biogas Plant has the following plant / process characteristics:Site classification:Start of operation:Amount of substrate treated:Type of substrate:Substrate recipe:Reactor type:Digestion temperature:Operational mode:On-line measurements:Off-line measurements:Retention time:Digester volume:Number of digestersUtilization of biogas:Utilization of digestate:Ethanol stillage biogas plant (crop gas plant)200724 000 tons/yr90% ethanol stillageControlledCSTRMesophilicSemi-continuousGas flow, gas composition, pHTS, VS, VFA, Alkalinity, NH4-N40 days2 000m31Vehicle fuelBio-fertilizer15
Scheelegatan 3, 212 28 Malmö Tel 040-680 07 60 Fax 040-680 07 69www.sgc.se [email protected]
SGC svarar för utgivningen av rapporterna medan uppdragstagarna för respektive projekt eller rapportförfattarna svarar för rapporternas innehåll. Den som utnyttjar . and increase in the average BPR from 2.6 to 3.23 Nm3/m3/day. Thus, after operating Biogas OptimizerTM for a period of 40 days, the average BPR increased
