Biofuel analysis Quality assurance of biofuels 02 Metrohm ... • is the global market leader in titration • offers a complete portfolio for NIR and Raman analysis, in addition to all of the methods of • ion analysis – titration, voltammetry, and ion chromatography • is a Swiss company and manufactures exclusively in Switzerland • grants a 3-year instrument warranty and a 10-year warranty on chemical suppressors for anion chromatography • provides you with unparalleled application expertise • offers you more than 1800 applications free of charge • supports you with dependable on-site service worldwide • is not listed on the stock exchange, but is owned by a foundation • takes a sustainable approach to corporate management, putting the interests of customers • and employees ahead of maximizing profit Metrohm – customized analysis for the biofuel industry A demanding industry You can count on our support 03 Sustainable use of biofuels requires reliable and precise Not only do we provide you with the right instrumenta-analytical methods throughout – from the choice of raw tion but with complete solutions for the particular task at materials through to process optimization and on to the hand. Your partners at Metrohm are experienced profes-compliant final product. sionals who help you with customized application sup- port and service. As a leading manufacturer of instruments for chemical analysis, we are quite aware of these challenges. We On the following pages, discover the solutions Metrohm offer you state-of-the-art instrumentation helping you to offers the biofuel industry in general and you in particu-check and improve the quality of biofuels and corre- lar, to ensure the quality and safety of your products. sponding blends as well as to comply with the standards – in your laboratory but also atline and online in the process environment. Quality assurance of biofuels 04 Keen interest in biofuels High quality standards Interest in biofuels has greatly increased in recent years. Too much water and the presence of alkali metal or alka-The reasons are the diminishing reserves of crude oil and line earth metal ions as well as sulfate and chloride ions the simultaneous increasing demand for mineral oil as have a negative effect on the fuel quality and can dam-well as the environmental problems linked with burning age the fuel system of the vehicle. With bio fuels based fossil fuels. In addition to a neutral CO balance, bioge nic on fatty acids, there is an in creased risk of polymerization 2 fuels are generally characterized by their very good mi - at higher temperatures in the ab sence of antioxidants or cro biological degradability, which is why they are suitable in the presence of nonferrous metals. With the aim of for use in ecologically sensitive areas. Furthermore, alter-avoiding these problems, the manufacturers of biofuels native fuels can usually be produced locally and ther eby and motor vehicles have developed quality standards in reduce dependence on imported raw materials. which testing methods and quality parameters for bio- fuels are defined. Biodiesel and bioethanol production Biodiesel is usually produced from vegetable oils or ani-A substantial number of the test methods that are stipumal fats. In an acid-, base-, or enzyme-catalyzed reaction, lated in international standards can be carried out with the triglycerides of the oil or fat are transesterified with Metrohm instruments and Metrohm application methods. me thanol to form fatty acid methyl esters (FAME), which are also known generally as biodiesel. By contrast, bioethanol is made from products that con- tain sugar or starch. Microbial fermentation of the sugar within the biomass with the help of yeast cultures is a technology that is well-established and widely used com-mercially. A great hope for the future is cellulosic ethanol made from lignocellulose-containing waste materials, which has so far only been produced in pilot plants. Cel-lu losic ethanol is characterized by an especially favorable carbon footprint. Selected standards from the field of biofuel analysis Minimum requirements and test methods 05 To ensure the quality of (bio)fuels, there are standards in prescribed test methods listed below to check the limits. place that set minimum requirements in the form of lim- If an alternative test method is indicated for monitoring its for impurities and the test methods to be used. the limits, this is shown by the «√» symbol. Metrohm instruments are highly suitable to carry out the Biodiesel Biodiesel is sold as a pure fuel and in blends with fossil minimum requirements for biodiesel used as heating oil. fuels. The minimum requirements are set out in the spe - EN 590 applies to diesel fuels that contain up to 7% bio-ci fications EN 14214 (pure fuel and blend stock) and diesel and ASTM D7467 applies to those that contain ASTM D6751 (only blend stock). EN 14213 describes the between 6 and 20% biodiesel. Requirements and test methods Test method Method Page EN 14214 ASTM D4806 EN 590 EN 14213 ASTM D7467 Acid number EN 14104 ASTM D664 – Titration 7 Iodine number EN 14111 – – Titration Water content EN ISO 12937 √ EN ISO 12937 KFT 10 coulometric EN 15751 EN 15751 Oxidation stability EN 15751a EN 16568b Oxidation stability 12 (EN 14112) (EN 14112) Free and total glycerol √ ASTM D7591 – Ion chromatography 14 Alkali metal and √ √ – Ion chromatography alkaline earth metal 15 Antioxidants recommended recommended recommended Ion chromatography Sulfur content √ √ √ CIC 18 KFT = Karl Fischer Titration, CIC = Combustion Ion Chromatography aApplies to pure biodiesel and blends that contain at least 2% (v/v) biodiesel bAging of the sample proceeds at 120 °C instead of 110 °C as stipulated in EN 15751 Bioethanol The minimum requirements for bioethanol as a blend com- and ASTM D4806. ASTM D5798 relates to ethanol-gaso- ponent in gasoline are documented in standards EN 15376 line blends E75–E85. Requirements and test methods Test method EN 15376 ASTM D4806 Method Page 4545 ASTM D5798 pH value EN 15490 ASTM D6423 pH value e e 6 Conductivity DIN 51627-4 – Conductivity Total acid number and acidity EN 15491 ASTM D1613 Titration Inorganic chloride content EN 15484 ASTM D512 Titration 8 Total inorganic sulfate content – ASTM D7318 Titration EN 15489 ASTM E1064 KFT Water content coulometric 11 – ASTM E203 KFTvolumetric ASTM D7319 Inorganic chloride content EN 15492 Ion chromatography 16 ASTM D7328 Total and potential inorganic ASTM D7319 EN 15492 Ion chromatography 16 sulfate content ASTM D7328 Sulfur content √ √ CIC 18 Copper content √ √ Voltammetry 20 KFT = Karl Fischer Titration, CIC = Combustion Ion Chromatography Further test methods for the fuel sector that comply with the standards can be found in the brochure «Petrochemical analysis» (8.000.5143EN). pH value and conductivity measurement e 06 Bioethanol pH value Conductivity e A combined pH glass electrode with ground-joint dia- Electrical conductivity is an important analytical sum phragm is recommended for measuring the pH value in parameter for detecting and monitoring corrosive organic solvents. Because pH determination according ionic constituents in ethanol and ethanol fuel. e to ASTM D6423 and EN 15490 is time-controlled, it is Because of the considerably lower conductivity essential that the sensor has a rapid response time. The in nonaqueous systems, very sensitive meas-EtOH-Trode with a special membrane glass and the very uring systems are required. The stainless-precise fixed ground-joint diaphragm is particularly suit-steel conductivity measuring cell able for measuring the pHe values of biofuels. The double- (6.0916.040) with Pt 1000 temperature junction system allows the free choice of the elec trolyte sensor, in con junction with the flexible (e.g., 3 mol/L KCl in ASTM D6423 and 1 mol/L LiCl in EN 856 Con ductivity Module, is ideally 15490). The pH meter used for the mea surement should suited for this application in accor-possess the following GLP functions, among others: dance with DIN 51627-4. • Three-point calibration with automatic buffer recognition • Temperature compensation • Calibration data monitoring • Automatic measured value recording • Result memory with identification The pH meter 827 pH lab for laboratory use and the handy, battery-operated 826 pH mobile offer all these functions with extremely comfortable operation. The electrode for measuring pH values in ethanol e The laboratory pH meter 827 pH lab 07 Titration Biodiesel Acid number Iodine number The acid number is a sum parameter for all acidic com- The iodine number is a measure for the number of double ponents; at the same time it is a measure for the long-term bonds in a sample. It is the amount of iodine (in g/100 g stability and corrosiveness of the biofuel. The smaller the sample) that can be added to the sample under the given value, the higher the quality. Standard EN 14104 sti pu-conditions. The determination of the iodine number in lates a nonaqueous potentiometric acid-base titration for fatty acids or biodiesel is covered by European standard determining the acid number. This involves dissolving the EN 14111. sample in a bioethanol-diethyl ether mixture and titrating it with potassium hydroxide dissolved in 2-propa nol An aliquot of the fatty acid or biodiesel sample is dis- (0.1 mol/L). solved in a mixture of cyclohexane and glacial acetic acid and treated with Wijs reagent. After a defined time has As organic solvents are used, the manual working steps elap sed, potassium iodide and water are added. The re - should be reduced to a minimum. With its space-saving leased elemental iodine is then titrated with sodium thio-Dosino technology, the Titrando allows fully automatic sulfate solution. EN 14111 allows both optical (with and safe solvent addition. The Solvotrode, an excellently starch solution as the indicator) and potentiometric end-shielded combined pH glass electrode, has been specially point de termination. developed for nonaqueous titrations. The separable ground-joint diaphragm guarantees stable potentials and is easy to clean. Extremely comfortable, rapid and precise is the determination when using the automated analysis system MATi 02. 08 Bioethanol Chloride content Sulfate content The chloride content in bioethanol fuels is the subject of A proven method for sulfate determination according to ASTM D512. Quantitation can be carried out by mercuri-ASTM D7318 is potentiometric titration with lead nitrate metric or argentometric titration or by direct determina-using a Pb-selective electrode. The pH value of the sample tion with a Cl-selective electrode. Argentometric titration is adjusted to pH 3–5 with perchloric acid and the sulfate (with silver nitrate) is the method of choice because of its is then precipitated out with lead nitrate solution. The environmental advantages and very high precision. A Pb-selective electrode detects the first excess of lead ions de fined volume of the sample is pipetted into the titra-at the equivalence point. tion cell, treated with 5 mL nitric acid (2 mol/L), and then tit ra ted against silver nitrate solution (0.01 mol/L). Ac cordingly, EN 15484 in EN 15376 describes the po ten tio metric titration of inorganic chlorides with a 0.1 mol/L solution of silver nitrate after dissolving the evaporation residue in dei o nized water. Acidity and total acid number Standards ASTM D4806, ASTM D5798, and EN 15376 set out the maximum permissible acid content in bioeth- anol. The two test methods stipulated therein (ASTM D1613, EN 15491) specify acid-base titration with visual indicator endpoint detection. The Titrando – the allrounder for potentiometric titration The wide range of potentiometric applications for bio- • The space-saving Dosino technology with numerous 09 fuels requires a highly flexible titrator. No other titration liquid handling functions simplifies sample preparation system offers more flexibility and ease of use than the and allows automatic preparation and emptying of Titrando. burets without operator intervention – it is no longer necessary to handle organic solvents. • With Touch Control or tiamo – titration and more – • Intelligent dosing units and electrodes eliminate confu-operation is perfectly easy. sion. Extensive GLP functions guarantee safe and error- free work. • The Titrando is unbelievably flexible – it covers the whole range from a simple stand-alone titrator up to a fully automatic titration system with sample changer, direct balance connection and barcode reader. The Titrando offers maximum flexibility and operating comfort. Water determination according to Karl Fischer 10 The presence of water in biofuels reduces their calorific Coulometer and Titrando value and increases the corrosion rate. All coulometers from Metrohm easily meet all the specifications stipulated in the standard and are outstandingly Biodiesel suitable for this application. In most cases, the sample can Water as a contaminant be injected directly into the reaction solution. To improve Water hydrolyzes the ester bonds of fatty acid methyl the solubility of the samples, xylene (dimethylbenzene) is esters, leading to the formation of fatty acids. Consuming added to the KF reagent. additional NaOH, these acids form soaps, which make the subsequent removal of glycerol more difficult. Biodiesel Karl Fischer oven method with a high water content has a clearly lower oxidation Some biodiesel fuels contain additives that could partici-stability. The lower the latter, the greater the probability pate in side reactions during the direct coulometric Karl that oxidation products will be formed during a longer Fischer titration. In such cases, Metrohm recommends storage period. These could damage the engine, in parti-that the biodiesel sample is not injected directly into the cu lar the fuel injection system, by forming deposits. reaction solution. Instead, the water contained in the biodiesel should be driven off in a Karl Fischer oven. The Maximum permissible water content 860 KF Thermoprep is suitable for this. The water is driven To avoid the drawbacks mentioned above, EN 14214 off at 120 °C and transported to the titration cell of the limits the water content of biodiesel to 500 mg/kg. Test KF Coulometer in a stream of carrier gas (dry air or inert method EN ISO 12937 «Petroleum products – Deter mi na-gas). This process can be completely automated with the tion of water – Coulometric Karl Fischer titration method» 874 USB Oven Sample Processor. specified in EN 14214 describes the coulometric Karl Fischer titration for determining the water content. 874 USB Oven Sample Processor with 851 Titrando for the 852 Titrando with coulometric and volumetric titration cell for automatic determination of the water content in samples determining trace amounts of water containing oil. Side reactions and contamination of the KF coulometer cell are avoided. 11 Bioethanol Gasoline-alcohol blends Bioethanol is mixed with gasoline in various ratios to reduce both the demand for gasoline and environmental pollution. The gasoline-alcohol blend is known in the USA as gasohol and in Brazil as Gasolina Tipo C. In the USA, the mixtures E10 and E85, which contain 10 and 85% bioethanol respectively, are widespread. In Brazil, the bioethanol content of most blends lies between 21 and 23%. Test methods The ASTM E1064 «Standard Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration» and EN 15489 standards describe the coulometric Karl Fischer titration for determining the water content. For a water content > 2%, the recommended test method is volumetric titration as per ASTM E203. The volumetric KF titrators from Metrohm meet all the specifications required by the standards and are therefore extremely suitable for this application. 901 Titrando with 900 Touch Control and 803 Ti Stand Oxidation stability Biodiesel 12 Measuring principle Fatty acid methyl esters are produced from a vegetable To determine the oxidation stability with the Rancimat oil, usually obtained from oil seed, by transesterification method, air is passed through the sample at an elevated with methanol. Both feedstock and biodiesel have a rela-temperature to cause artificial aging. During this process tively short storage life as they are slowly oxidized by long-chain organic molecules are oxidized by oxygen, atmospheric oxygen. The resulting oxidation products can whereby highly volatile organic substances form besides damage vehicle engines. For this reason, the oxidation insoluble polymer compounds. The former are driven out stability is an important quality criterion for biodiesel and by a stream of air, absorbed in water, and detected there vegetable oils and must therefore be checked regularly by measuring the conductivity. The time until these de - during manufacture and storage. composition products form is referred to as the induction time or the Oil Stability Index (OSI) and characterizes the International quality standards resistance of the sample to oxidative aging processes, The oxidation stability of fatty acid methyl esters is that is, the oxidation stability. included as an essential parameter in many standards, as indicated in the table on page 5. They define the mini-893 Professional Biodiesel Rancimat and StabNet mum quality requirements of biodiesel that is sold as a software fuel or heating oil. The 893 Professional Biodiesel Rancimat is a modern, PC-controlled instrument that allows the simple and reliable determination of oxidation stability in biodiesel and biodiesel blends. Up to eight samples can be measured simultaneously. The effectiveness of antioxidants can also be determined with the 893 Professional Biodiesel Rancimat. The 893 Professional Biodiesel Rancimat allows oxidation stability to be determined in accordance with numerous international standards. 13 Start buttons on the instrument Next to each measuring position there is a button with which determination can be started immediately after the sample has been placed in the heating block. The start button is completely sealed on the outside, so no liquids such as sample or water can enter. Cover with built-in conductivity cell The conductivity cell, with its electrical connections, is incorporated in the measuring vessel cover. When the cover is placed in position, the cell is immersed in the water and is immediately in the right position. At the same time electrical contact is made to the measuring electronics in the instrument. Modern Software for stability measurements StabNet is the modern and user-friendly software for carrying out stability measurements and archiving the measurement data. The characteristic features of StabNet are its ease of use and flexibility. Further advantages of StabNet • Database with flexible filtering, sorting and statistical functions • Network-compatible due to client-server functionality • Meets all the requirements of FDA and GLP Ion chromatography 14 State-of-the-art ion chromatography (IC) permits the (monoglycerides and diglycerides) as by-products after efficient separation and determination of inorganic and transesterification of the triglycerides. Incomplete trans - low-molecular weight organic anions and cations. Dif fe-est erification and/or separation of glycerol causes glycerol rent separation mechanisms and detection types as well contamination in the biodiesel, which speeds up fuel as the possibility of automation and sample preparation aging and leads to deposits in the engine and blo cked render IC a versatile analytical technique for the biofuel filters. To ensure engines operate properly, the American and petrochemical industry. ASTM D6751 and the European EN 14214 limit the maximum total glycerol content (i.e., free and bound Biodiesel glycerol) to 0.24 and 0.25% (v/v), respectively. Free and Glycerol bound glycerol is determined by ion chromatography The production of biodiesel from vegetable oils and animal and subsequent pulsed amperometric detection in fats leads to the formation of free and bound glycerol accordance with ASTM D7591. 9000 8000 7000 glycerol; 10.0 mg/L 6000 5000 ent [nA] 4000 urrC 3000 2000 1000 Glycerol determination using pulsed amperometric detection; 0 0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2 column: Metrosep Carb 2 - 150/4.0; eluent: 100 mmol/L NaOH, Time [min] 10 mmol/L sodium acetate, 1 mL/min; column temperature: 30 °C, sample volume: 20 μL Alkali metals and alkaline earth metals Antioxidants 15 Whereas sodium and potassium contaminants stem from The oxidation stability of fatty acids and of the fatty acid the hydroxides used in transesterification, calcium and methyl esters synthesized from them can be significantly magnesium impurities result mainly from the use of the improved by adding antioxidants. Biodiesel based on water employed in biodiesel washing to extract water-rapeseed oil already contains a natural protection against soluble foreign substances such as methanol and glycer-oxidation – vitamin E (d-α-tocopherol). In addition, one ol. In higher concentrations, these metals cause operating of the Baynox® products, whose structures were inspired problems in the engine, which is why their concentration by that of vitamin E, is added to the biodiesel as a stabi-in the fuel is regulated by international specifications. lizer. Both antioxidants inhibit both oxidation to corrosive Both EN 14214 and ASTM D6751 allow a maximum total acids and formation of insoluble polymers and thus pre-concentration of 5 mg/kg for the two alkali metals and vent the injection nozzles from being blocked. Anti oxi-the two alkaline earth metals, respectively. dants are determined in the course of quality control, espe cially for monitoring and assessing storage stability. The chromophores present in vitamin E and Baynox® allow sensitive spectrophotometric detection without prior post-column derivatization. 581.4 140 581.6 120 581.8 582.0 100 582.2 calcium; 4.7 mg/L 80 ; 48.7 mg/L® 582.4 582.6 60 Baynox Intensity [mV] 582.8 potassium; 1.4 mg/L Conductivity [µS/cm] 40 magnesium; 0.7 mg/L 583.0 583.2 sodium; 0.2 mg/L 20 tocopherol; 4.8 mg/L 583.4 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 19 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Time [min] Time [min] Alkali and alkaline earth metals in a biodiesel sample. The sam-Biodiesel fuel spiked with 50 mg/L Baynox® and 5 mg/L ples are extracted with dilute nitric acid, dialyzed, and then in- α-tocopherol. To improve solubility, dichloromethane is added to jected directly into the IC system. The complete sample prepa-the eluent and analyte solutions. Column: Prontosil 120-5-C18; ration procedure and analysis takes place fully automatically. eluent: 90% acetonitrile and 10% dichloromethane, 1.0 mL/min; Column: Metrosep C 4 - 150/4.0; eluent: 2 mmol/L HNO with column temperature: 35 °C; wavelength: 220 nm; sample volume: 3 10% acetone, 0.9 mL/min; column temperature: 30 °C; sample 10 μL; sample dilution 1:1000 (w/w) volume: 10 μL 940 Professional IC Vario for fully automatic cation determination with Metrohm Inline Extraction and Inline Dialysis 16 Bioethanol Chloride and sulfate Bioethanol is either used in pure form as a fuel or blendIn addition, there are also the ion chromatographic ed with fossil fuels. Contaminants in the form of inorga-methods described in ASTM D7328 and EN 15492: be - nic chloride and sulfate salts are corrosive and lead to fore injection, the denatured ethanol sample is evapo-deposits and blockages in the fuel filter and injection rated to dryness and then diluted for injection with 1% nozzles. The international ethanol specifications EN 15376, solution of hydrogen peroxide (ASTM D7328) or with ASTM D4806, and ASTM D5798 regulate the sulfate and de ionized water (EN 15492). chloride content in bioethanol and in bioethanol fuel blends. denaturant: methyl ethyl ketone 10 According to ASTM D7319, the total content of inorga- 9 ] 8 nic chloride and sulfate is determined after direct injec-7 tion of the ethanol sample and separation on an anion- 6 chloride; 2.5 mg/L 5 exchange column by conductivity detection. If hydrogen 4 peroxide is previously added, sulfur-containing species Conductivity [µS/cm 3 such as sulfites, sulfides, or thiosulfates can be oxidized 2 sulfate; 1.0 mg/L 1 to form sulfate and are quantified as potential sulfate 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 content. The analytical system is extremely robust and Time [min] guarantees outstanding reproducibility and repeatability Chromatogram of a denatured ethanol sample spiked with even after 1500 determinations carried out in round 2.5 mg/L chloride and 1 mg/L sulfate; column: Metrosep A Supp robin tests. 5 - 150/4.0; eluent: 3.2 mmol/L Na CO , 1 mmol/L NaHCO , 2 3 3 0.7 mL/min; column temperature: 35 °C; sample volume: 10 μL Cellulosic ethanol 17 Carbohydrates and organic acids Cellulosic ethanol is one of the second-generation biofu-ment be fore fermentation and then has to be converted els and is produced in pilot plants from lignocellulose-into fer mentable sugars using special enzymes. Fre- containing waste materials such as straw, wood, and quently, during pretreatment of the plant material, fer-ba gasse. Compared with bioethanol made from starch mentation inhibitors appear in the form of carbohydrates and sugar cane, it has a considerably better carbon foot-and orga nic acids (e.g., gluconic acid), which kill the print. Fur ther more, the cheap raw materials needed to microorganisms used in the subsequent fermentation. produce it are not in competition with food production. Fast and sensitive ion chromatographic determination of The biomass, however, which is made up of complex organic acids and carbohydrates contributes substantially sugars, needs to undergo chemical or thermal pretreat-to the optimization of the fermentation process. Fuel blends 18 Sulfur content The burning of sulfur-containing fuels leads to the emis-the determination of the sulfur and halogen content in sion of air-polluting sulfur oxides into the atmosphere. combustible solid and liquid matrices by combining com-Furthermore, high sulfur concentrations have an adverse bustion digestion (pyrolysis) with subsequent ion chro-effect on the ease of ignition of fuels and their stability matography. It can be fully automated and excels in its during storage. A fast and reliable method for determin-high sample throughput and excellent precision and ing the sulfur content is required. Combustion IC allows accuracy. In combustion digestion (pyrolysis), sulfur compounds are converted into sulfur dioxide, and halogen compounds are converted into hydrogen halides and elemental halogens. These gaseous combustion products are fed into an oxidizing absorption solution and detected as sulfate and halide by way of the ion chromatography that follows. 19 Determination of the sulfur and chlorine content in a) B100 biodiesel sample and b) B5 biodiesel blend; column: Metrosep A Supp 5 - 150/4.0; eluent: 3.2 mmol/L Na CO , 1.0 mmol/L NaHCO , 0.7 mL/min; column temperature: 30 °C; sample volume: 100 μL, absorp-2 3 3 tion solution: 30 mg/L H O 2 2 Voltammetry 20 Voltammetric trace analysis is used for determining elec-determinations are usually carried out in aqueous solu- trochemically active substances. These can be inorganic tions after digestion of the sample. or organic ions or even neutral organic compounds. Voltammetry is suitable in particular for laboratories in Vol tammetry is often used for supplementing and vali-which, with a medium sample throughput, only a few dating spectroscopic methods and is characterized by parameters need to be controlled. It is often used for low equip ment costs, comparably low investment and spe cific applications that are either not feasible or too operating costs, short analysis times, and an outstanding costly using other techniques. accuracy and sensitivity. Unlike spectroscopic methods, voltammetry can also differentiate between different oxi-884 Professional VA dation states of metal ions or between free and bound The 884 Professional VA is a flexible measuring instru-metal ions. This is referred to as speciation analysis. ment for accurate and sensitive voltammetric and polarographic analyses. The analyses can be easily automated Broad application range by adding Dosinos and a sample changer. The accompa- Voltammetric measurements can be carried out both in nying viva software enables individual optimization of aqueous solutions and in organic solvents. Heavy metal methods. 21 Bioethanol Copper Ethanol is used increasingly in gasoline as a blending com ponent. Contaminants can cause problems in the engine. For example, traces of copper catalyze the oxidation of hydrocarbons. As a consequence, polymer com- pounds can form that can lead to deposits and block- ages in the fuel system. Specifications EN 15376 and ASTM D4806 describe the minimum requirements for ethanol that is blended with gasoline and allow a copper content of 100 μg/kg. By contrast, standard ASTM D5798 sets the copper content in ethanol-gasoline blends E75-E85 at 70 μg/L. Using voltammetry, copper can be measured without any sample preparation in pure ethanol or ethanol-gasoline blends (E85, 85% ethanol and 15% gasoline) in the range between 2 and 500 μg/kg. Voltammetric determination of copper Potentiostats and galvanostats Corrosion resistance in biofuels and biofuel blends 22 Biodiesel shows a high corrosion potential The corrosion resistance of storage tanks, process pipe-Biodiesel has a higher electrical conductivity and is more work, and pipelines is an important material requirement hygroscopic than conventional diesel fuel. This means for the storage and transportation of fuels. The materials that, when stored for a long time, it absorbs more water, along which fuels are conveyed, especially, can suffer which in turn leads to hydrolysis of the ester bonds and considerable damage due to stress corrosion cracking thus to the formation of free fatty acids. The pH value (SCC) and microbially-induced corrosion (MIC). Whereas falls and the microbiological activity responsible for deg-the corrosion behavior occurring in relation to fossil fuels radation increases. With the biotic degradation reactions, has been adequately studied and documented – like, for the properties of the biodiesel also change; in particular, example, in ASTM D7548 – systematic studies of biofuel the corrosion potential at the material-fuel interface in - corrosion are still lacking to a large extent. What is clear, creases. is that, owing to the various chemical and physical properties, fossil fuels and biofuels differently influence the corrosion behavior at the interface between the material and fuel. Corrosion behavior is generally expressed in terms of the corrosion potential as a characteristic electrochemical value. 23 The material-fuel interface Electrochemical methods provide the possibility for de - that incorporates a large number of preprogrammed termining the corrosion resistance of various materials in methods. For example, the corrosion processes taking fuels easily and conveniently. The Autolab PGSTAT100N place on the conducting material-fuel interface can be potentiostat/galvanostat combined with the FRA2 Im pe-determined effectively by linear polarization or electrodance Analyzer Module is a powerful analytical system chemical impedance spectroscopy (EIS). The Autolab PGSTAT100N – a potentiostat/galvanostat for electrochemical determinations (maximum 100 V compliance voltage) in media with low conductivity www.metrohm-autolab.com Process analysis 24 Customized process control In the biofuel industry, continuous control of the produc-Network integration tion process as well as the monitoring of the product The online analyzers from Metrohm Process Analytics are quality and the composition of any waste streams is all equip ped with possibilities for digital as well as analog crucial. With the process analyzers of Metrohm Process outputs. Results, for example, can be transferred via Analytics, this is possible 24 hours a day, 7 days a week. 4–20 mA out puts, whereas alarms can be transmitted via The analyzers are used directly on-site, as close as possi-digital out puts. Digital inputs, in turn, can be used for ble to the process, and run completely stand-alone with-remote start-stop purposes. out operator intervention. Moreover, it does not make a difference whether a single parameter is to be deter-Robust design mined in a single sample stream or several different In many cases, the IP66-NEMA4 housing of the analyzers parameters are to be determined in complex, multiple will be sufficient. In some cases in the biofuel industry, sample streams – the Metrohm Process Analytics engi-however, explosion-proof systems are required. For those neers pro vide you with the ap pro priate online or atline circumstances, the ADI 2045Ti Ex proof Analyzer is avail-analyzer. able in a stainless-steel explosion-proof version for Zone I or Zone II according to the explosive atmosphere directives Proven wet-chemistry methods (ATEX). The Applikon analyzers are based on wet-chemical analysis techniques such as titration, colorimetry, or ion-selective electrode measurements. In online analysis, sampling and sample preconditioning are at least as important as the analyzer itself. Metrohm Process Analytics has a lot of expertise in this area and is capable of offering customized sampling systems, for example, for pressure reduction, filtering, and degassing. Many of the analysis methods that are used in the labo- 23 ratory can be transferred to an online analyzer. Typical applications are: Water content Presence of too much water in the fuel reduces the calorific value, promotes corrosion, encourages bacterial growth, and increases the likelihood that oxidation products will form. As in the laboratory, Karl Fischer titration, particularly coulometry, is the method of choice for the online determination of the water content in any biofu-Cuvette for colorimetric determinations els. Analyzers from Metrohm Process Analytics allow determination in either one or more than one sample hydrolysis of the fatty acid methyl esters that is initiated streams. by the penetration of water. FFA determination is also used in initial checking of the vegetable oils used in transesterification. Determination is carried out in the ADI 2045Ti analyzer using colorimetric titration or, if there is severe turbidity, potentiometric titration. Total phosphate content Phosphate contamination in biodiesel results from the phospholipids that occur ubiquitously in vegetable oils and from the phosphoric acid added during the production process. After UV digestion in the presence of sulfu-ric acid, the resulting orthophosphate is determined col-orimetrically. The combination of digestion and colori- metric determination is only possible in the ADI 2045Ti Process Analyzer. ADI 2045Ti Process Analyzer for coulometric determination of water content according to Karl Fischer Potassium Potassium residues in biodiesel result from the catalyst and lead to deposits in the fuel injection system. They are determined with ion-selective electrodes. Depending on the required limit of detection, the determination can be carried out either with an ALERT analyzer or with the ADI 2018 analyzer, which is equipped with high-precision piston burets and is therefore more precise. Free fatty acids (FFA) An excessively high proportion of free fatty acids pro- motes corrosion and, together with the catalyst, leads to soap formation. In addition, a rising concentration of free fatty acids in the biodiesel is usually a sign of the ADI 2045Ti analyzer for determining the total phosphate content 26 Metrohm Quality Service – service you can rely on Reliable results – for the lifetime of the analyzer Metrohm Compliance Service Chemical analysis accompanies the biofuel industry You can trust Metrohm Compliance Service when it comes from the choice of raw materials, through specifica- to the professional qualification of your analyzers. Ins tal - tion-compliant production, and on to end product qual- lation Qualification/Operational Qualification (IQ/OQ) or ity control. Whoever is responsible in the laboratory for Certified Installation (CI) saves you time and money be - the accuracy of the results must not make compromis- cause we configure the system according to your re quire-es. The golden rule here is that professionally installed ments and ensure quick and reliable commissioning. and commissio ned systems that are serviced regularly guarantee the grea test possible reliability. User instructions lay the foundations for safe, error-free operation. The Metrohm Compliance Service also includes With Metrohm Quality Service you are on the safe side comprehensive documentation and guarantees com pli-from day one. From installation and start-up, to regular ance with the standards of quality management systems maintenance and fast repair – if problems such as GLP/GMP and ISO. arise – we guarantee that you can rely on your instrument and gain max- imum uptime from your invest- ment. Metrohm Quality Service 27 Metrohm’s global Quality Service, and regularly sched- particular need. With a Total Care Contract, for example, uled preventive maintenance in particular, extends your you can rely on the optimum performance of your instrument’s lifetime and ensures trouble-free operation. Metrohm instruments at all times, incurring no additional Maintenance work is carried out by qualified and certi-costs whatsoever and benefit from complete and com- fied service engineers. You have the option of selecting pliant documentation. different types of service contracts depending on your Metrohm Quality Service Customer benefits • Minimizes downtime through preventative maintenance • Cost control and savings through free or discounted replacement materials and Metrohm Care Contracts consumables • Guaranteed raction times and rapid on-site repair • Documented instrument certification as an ideal preparation for audits • High data security and maximum system performance through regular, profes-Metrohm Software Care sional software maintenance • Customized services and documentation for analytical instrument qualification (AIQ) Metrohm Compliance Service • Professional start-up (IQ/OQ or Certified Installation) and requalification or recertification by specifically trained employees Metrohm Remote Support • Quick resolution of software and application issues directly at the workplace • Calibration of burettes (e.g., dosing and exchange units) with certification Metrohm Dosing Test • Accurate measurement results • Verification documentation for compliance with regulations and efficient audits • Rapid availability of repaired instruments thanks to decentralized repair workshops around the world and a central workshop at the manufacturer site Metrohm Repair Service • Highly qualified service technicians ensure sustainable repair success • Rapid resolution of problems and minimized downtimes through on-site emer-gency services and express repairs • Original spare parts, made in Switzerland and available worldwide • Short delivery times through warehousing from local distributors Metrohm Spare Parts • Investment security through ten-year spare parts guarantee after discontinuation • Free access to the Metrohm Application Finder (www.metrohm.com/en/ applications/) with more than 1800 applications (Application Bulletins, Application Notes, monographs, technical posters, and technical articles) Metrohm Application Support Rapid and professional resolution of any application issues through personal consultations with our specialists by e-mail, telephone, or remote support • Support for the solution of complex analytical problems, as well as method optimization on-site or at our application laboratories • Basic and advanced training with local representatives, at the Metrohm Academy or directly on-site Metrohm Training Programs • Efficient and proper use of all analytical methods, as well as results reliability through competently trained users • Training documentation and certificates for trouble-free audits Ordering information 28 pH and conductivity measurement e pH measurement in bioethanol e 2.827.0X1X 827 pH lab with Pimatrode or Unitrode 2.826.0010 826 pH mobile 6.0269.100 EtOH-Trode 6.2104.020 Electrode cable Conductivity measurement in bioethanol 2.856.0110 856 Conductivity Module with 900 Touch Control 6.0916.040 Conductivity measuring cell (stainless steel) c = 0.1 cm–1 with Pt 1000 6.1418.250 Titration cell with thermostat jacket 6.1414.010 Titration cell lid with 5 openings Titration Acid number in biodiesel 2.905.0010 905 Titrando 2.900.0010 900 Touch Control 2.801.0040 801 Magnetic Stirrer 2.800.0010 800 Dosino (2 × for addition of titrant and solvent) 2.814.0030 814 USB Sample Processor MATi 02 Automated TAN/TBN determination 6.3032.220 Dosing Unit 20 mL (titrant) 6.3032.250 Dosing Unit 50 mL (solvent) 6.0229.010 Solvotrode easy Clean, fixed cable, plug F 6.2320.000 Electrolyte TEABr = 0.4 mol/L in ethylene glycol Iodine number in biodiesel 2.905.0010 905 Titrando 2.900.0010 900 Touch Control 2.801.0040 801 Magnetic Stirrer 2.800.0010 800 Dosino 6.3032.220 Dosing Unit 20 mL (titrant) 6.0471.300 iPt-Titrode Chloride in bioethanol 2.905.0010 905 Titrando 2.900.0010 900 Touch Control 2.801.0040 801 Magnetic Stirrer 2.800.0010 800 Dosino (2 × for addition of titrant and nitric acid) 6.3032.220 Dosing Unit 20 mL (titrant) 6.3032.210 Dosing Unit 10 mL (nitric acid) 6.0470.300 iAg-Titrode Sulfate in bioethanol 2.905.0010 905 Titrando 2.900.0010 900 Touch Control 2.801.0040 801 Magnetic Stirrer 2.800.0010 Dosino (2 × for addition of titrant and perchloric acid) 6.3032.220 Dosing Unit 20 mL (titrant) 6.3032.210 Dosing Unit 10 mL (perchloric acid) 6.0502.170 Pb-selective electrode 6.0750.100 LL ISE Reference 6.2104.020 Electrode cable, 1 m, F 6.2106.020 Cable strand, 1 m, 2 × B 29 Water determination according to Karl Fischer Coulometric KF Titration 2.831.0010 831 KF Coulometer including generator electrode with diaphragm and Stirrer 2.756.0010 756 KF Coulometer including generator electrode with diaphragm, 728 Stirrer and integrated printer 2.851.0010 851 Titrando including generator electrode with diaphragm and 801 Magnetic Stirrer 2.899.0010 899 Coulometer including generator electrode with diaphragm and stirrer Volumetric KF Titration 2.870.1010 870 KF Titrino plus komplett 2.890.0110 890 Titrando including 803 Ti-Stand and Touch Control 2.901.0010 901 Titrando including titration cell and indicator electrode Coulometric and volumetric KF titration 2.852.0050 852 Titrando including generator electrode with diaphragm and 801 Magnetic Stirrer 2.915.0110 915 Ti-Touch with integrated stirrer KF Oven 2.874.0010 874 USB Oven Sample Processor 2.860.0010 860 KF Thermoprep 2.885.0010 885 Compact Oven Sample Changer Oxidation stability 2.893.0010 893 Professional Biodiesel Rancimat including software and accessories 6.6068.102 StabNet 1.0 Full Ion Chromatography Glycerol in biodiesel 2.930.2160 930 Compact IC Flex 2.850.9110 IC Amperometric Detector 2.858.0020 858 Professional Sample Processor 6.1090.420 Metrosep Carb 2 - 150/4.0 6.5337.010 IC Equipment Wall-Jet cell: Carb (Au, Pd) Alkali metals and alkaline earth metals in biodiesel 2.940.1110 940 Professional IC Vario ONE/Prep 1 2.858.0020 858 Professional Sample Processor – Pump 2.850.9010 IC Conductivity Detector 2.800.0010 800 Dosino 2.741.0010 741 Magnetic Stirrer 6.5330.120 IC equipment for dilution 6.5330.100 IC equipment for dialysis 6.2041.440 Sample rack 148 × 11 mL 6.1050.420 Metrosep C 4 - 150 /4.0 6.6059.312 MagIC Net 3.1 Professional Antioxidants in biodiesel 2.930.2160 930 Compact IC Flex Oven/Deg 2.944.0010 944 Professional UV/VIS Detector Vario 30 2.858.0020 858 Professional Sample Processor – Pump 6.2041.440 Sample rack 148 × 11 mL 6.2061.120 System Connector 6.2061.110 Tray with sensor for Professional IC Instruments 6.6059.311 MagIC Net 3.1 Compact Chloride and sulfate in ethanol 2.930.2560 930 Compact IC Flex Oven/SeS/PP/Deg 2.850.9010 IC Conductivity Detector 2.858.0020 858 Professional Sample Processor – Pump 6.2041.440 Sample rack 148 × 11 mL 6.5330.110 IC equipment for ultrafiltration 6.1006.530 Metrosep A Supp 5 - 250/4.0 6.2842.000 MSM-HC Rotor A 6.6059.311 MagIC Net 3.1 Compact Sulfur content in fuel blends – Combustion IC 2.930.9010 930 Metrohm Combustion IC 6.1006.520 Metrosep A Supp 5 - 150/4.0 Voltammetry 2.884.0110 884 Professional VA (MME) 2.884.1110 884 Professional VA semiautomated MME consisting of 884 Professional VA, measuring head for MME, and two 800 Dosinos. MVA-22 Fully automated Professional VA system consisting of 884 Professional VA, measuring head for the MME, 919 IC Autosampler plus for VA, and four 800 Dosinos for automatic addition of auxiliary solutions. Allows the automatic processing of up to 18 samples. This system is the optimum solution for automatic analysis of small sample series. Required accessories 6.5339.030 VA Electrode Kit 884 MME 6.6065.202 viva 2.0 Full Process analysis We offer online and atline Analyzers that meet any requirement in the process industry, from single-parameter to the most advanced multiparameter analyzers. Every analyzer is custom-tailored to the specific task at hand. ADI2045PL ProcessLab system for atline determination of various parameters using titration, colorimetry, and ISE ADI 201Y Series Single method Process Analyzers, available with titration, colorimetry, or ISE ADI 204Y Series Multifunctional Process Analyzers, available with titration, ISE, colorimetry, and voltammetry 2035 Series Analyzer family designed in 3 configurations: potentiometric, photometric, and thermometric titration ICON Analyzer Analyzer from the Plug and Analyze Series that performs photometric absorption measurements Alert Ion Analyzer Analyzer from the Plug and Analyze Series that is used for measuring single parameters by ISE Please contact your Metrohm supplier for further information. Please also consult www.metrohm.com 31 biofuels.metrohm.com G, CH-9101 Herisau ohm A , printed by Metr SW Subject to change Layout by Ecknauer+Schoch A 8.000.5149EN – 2015-09