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Assessment of best practices in UCO processing and biodiesel distribution

D4.3 - Guide on UCO processing and biodiesel distribution methods

T E C H N I C A L U N I V E R S I T Y O F C R E T E M a y · 2 0 1 3

PROMOTION OF USED COOKING OIL RECYCLING FOR SUSTAINABLE BIODIESEL PRODUCTION (RecOil) RecOil aims to increase sustainable biodiesel production and its local market intake by enhancing household used cooking oil collection and transformation. It assesses the “UCO to biodiesel” chain best practices, through a household survey, the industry expertise, the local authorities’ cooperation, and a review of the legal and market barriers and opportunities. The information gathered will integrate an online decision‐making guide: a tool to assist stakeholders in developing an UCO‐to‐biodiesel supply chain adjusted to local specifications. Pilot projects in promotion, collection, transformation and commercialization of UCO/biodiesel will be carried out according to the best practices identified. These projects will be living labs helping to validate the feasibility of these good practices but also showcasing and spreading the project’s results in a way that the achievements can be used to promote similar initiatives in other regions and by other entities. Promotional campaigns and communication tasks will be developed to guarantee stakeholders’ involvement and to increase public interest about UCO recycling, motivating a behavioral change among citizens. RecOil is supported by the European Commission within the frame of the Intelligent Energy for Europe Programme.

Nº CONTRACT IEE/11/091/SI2.616369 DELIVERABLE WP4 –D4.3 WP Leader AUTHOR(s)

Technical University of Crete, Renewable and Sustainable Energy Systems Lab Theocharis Tsoutsos, Tournaki Stavroula

DISSEMINATION LEVEL Public STATUS DATE

Version 3 Ver1: issued at July 15th, 2013. Current Revision 30/10/2013

The sole responsibility for the content of this [webpage, publication etc.] lies with the authors. It does not necessarily reflect the opinion of the European Union. Neither the EACI nor the European Commission are responsible for any use that may be made of the information contained therein.

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CONTENTS

1. INTRODUCTION………………………………………….…………………………................................…………...2

2. UCO COLLECTION PRACTICES…………………………………………….............................................…..3

2.1. Existing practices for the UCO collection.........................................................................3

2.2. Transport and Storage of UCO.........................................................................................5

2.3. Legal Limitations.............................................................................................................6

3. ASSESSMENT OF BEST PRACTICES FOR UCO PROCESSING TO BIODIESEL............................. 7

3.1. Quality characteristics of the collected UCO used for processing to biodiesel……........7

3.2. Existing processing technologies and practices……………………………………………….………...8

3.3. Common practices in transesterification…………………………………………………….…….……..10

3.3.1. Homogeneous ‐ catalyzed transesterification……………………………………………………….….10

3.3.2. Heterogeneous – catalyzed transesterification……………………………………..………….…..……11

3.3.3. Enzyme – catalyzed transesterification………………………………………………………………..…….12

3.3.4. Non – catalyzed transesterification……………………………………………………………….……………14

3.4 Comparative analysis of the most common practices…………………………………….…………16

3.5 Health and Safety……………………………………………………………………………………….….…….…..17

4. HARMONIZATION WITH THE EU DIRECTIVE FOR SUSTAINABILITY………………………….…….…19

5. CLIMATE AND GEOGRAPHICAL PARAMETERS…………………………………………………..…….………20

6. ENVIRONMENTAL PERFORMANCE AND IMPACTS ANALYSIS……………………….………….………22

7. DISTRIBUTION PRACTICES………………………………………………………………………………..…………….27

8. CONCLUSION……………………………………………………………………………………………………..………….29

9. REFERENCES……………………………………………………………………………………………….…….……………30

10. ABBREVIATIONS………………………………………………………………………….……………………….………..35

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1. INTRODUCTION

Used Cooking Oils (UCOs) are oils and fats that have been used for cooking or frying in the food processing industry, restaurants, fast foods and at a consumer level, in household; UCO can originate from both vegetable and animal fats and oils; they can be collected and recycled for other uses. It is estimated that currently around 90% of cooking oils and fat used in the EU are produced from vegetable oils, whereas in countries such as Belgium relatively much animal fats are used (Peters et al, 2013). According to moderate estimations in EU, the potential UCO to be collected is around 8L UCO/capita/year. Extrapolated to the total EU population of around 500 million, this means that 4 Mton of UCO are the annually capacity, seven times more than the current collected amount. This potential increases around 2% per year, following the annual increase of cooking oil usage in the EU‐15. In order to achieve this level of collection, the collection infrastructure should be improved (Anderssen et al, 2007). The current report aims to provide useful technical and practical guidelines of best methods to process the UCO‐to‐biodiesel chain, including recommendations for the interested policy makers and stakeholders, as a background document for the RecOil Guide. Existing practices are evaluated under different criteria including:

Techno‐economic analysis of the pre‐selected best practices;

Quality characteristics of the collected UCO;

Analysis of possible implications to the collection procedures;

Environmental performance and impacts analysis;

Risks and weaknesses.

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2. UCO COLLECTION PRACTICES

The quality of UCO as a raw material is critical for its transformation to biodiesel, since has impact

in all sequential stages, so the collection process is crucial for the following transformation

processes to biodiesel.

2.1. Existing practices for the UCO collection

Three (3) sourcing strategies of UCO have been identified (BIOSIRE):

A: Processor Decentralized collection: The biodiesel company sets up a door to door collecting system in order to collect direct from the “producers” of UCO (Figure 1).

B: Processor Centralized collection: The “producers” of UCO deposit them at centralized depots. The biodiesel company collects them directly from the depot (Figure 2).

C: Combined Supplied Collection: The biodiesel company supplies the raw vegetable oils to the “producers” of UCO and collects them for recycling as well (Figure 3).

Figure 1. Processor Decentralized collection (A)

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Figure 2. Processor Centralized collection (B)

Figure 3. Combined Supplied Collection (C)

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The above strategies are compared in Table 1.

Table 1. Advantages and Disadvantages of the different collection strategies (Roy, 2009)

Strategy Advantages Disadvantages

A. Processor Decentralized collection

Biodiesel processor has direct contact with the oil consumers, so they may educate them on the required quality of the oil (in order to be recycled) and how to reject inappropriate oil.

Expensive and time consuming collection process (dependent upon the number of households/consumers involved and the volume/quality of used oil per point.

Potential to deliver biodiesel to consumers during the collection process, cutting distribution costs and promoting biodiesel use.

Waste license required

Better working relationship and communication between processor and oil consumer.

The frequency of collection is usually determined by the oil user.

Eliminates waste collection fees for the oil user.

B. Processor Centralized collection

Low collection cost provided the depot(s) are located close to the processing facility

No direct control over the quality of the oil feedstock.

The collection to a centralised depot may already be established by a separate waste management company, reducing setup costs.

Higher raw material cost from depot.

If the depot can deliver the used oil to the biodiesel processer, no waste carrier license is required by the processor.

Biodiesel processor has less control over the efficiency of the supply chain.

The biodiesel processor incurs higher financial risk if purchasing from only one UCO depot.

C. Combined Supplied Collection

Reduced cost for supply chain activities. Competing with established oil suppliers.

Close supply chain communication.

2.2 Transport and Storage of UCO

Transport and storage are parts of the logistics chain, and as mentioned above they must follow good housekeeping guidelines. As a basic principle, these must be harmonized with the CEN/TR 15367‐3 “Prevention of Cross Contamination”. In parallel, the UCO supply chain can adopt partial or totally the following guidelines. The supply chain of UCO consists of the following stages:

Production site; the site where the UCO is produced.

Spot terminal; the first site where the UCO is initially collected.

Filling Terminal; the terminal where the UCO is loaded to the trucks for the last stage of the process; here is the point where the blending of UCO from different oils takes place.

Biodiesel refinery or Cleaning Terminal; the terminal where the biodiesel is manufactured.

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Cross contamination may occur at any stage of the supply chain and can be cause by inadequate: management of operations

inspection and maintenance

design of facilities.

To ensure good quality of UCO in the spot terminal, it is suggested to verify that the product meets specifications when it is delivered for further process and to keep procedures that will prevent contamination on its way to the biodiesel plant. Proper detailed attention to all activities from the collection to the final delivery to the biodiesel plant, or to the purification installation is essential for the quality of the produced biodiesel.

There should be operating quality protecting procedures covering:

Delivery

Sampling

Inspection

Testing

Documentation

Volume accounting.

These procedures should be reviewed and updated taking into account the UCO quality changes during seasonal or feedstock transitions. Another important issue, in any production stage, is that the involved personnel should be properly trained so that they understand the importance of applying quality standards in the operating procedures. Even if the used installation/equipment is well selected and designed, general hardware faults can appear over time with careless inspection and maintenance. All the above will affect the biodiesel manufacturer to maintain the product quality at the required level.

2.3 Legal Limitations

The following Regulations, Directives and Decisions of the European Legislation must be followed in the collection of UCO:

REGULATIONS

REGULATION (EC) No 1013/2006 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 14 June 2006 on shipments of waste.

DIRECTIVES

Council Directive 1975/439/EEC of 16 June 1975 on the disposal of waste oils (75/439/EEC).

Council Directive 1991/689/EEC of 12 December 1991 on hazardous waste. (91/689/EEC).

Council Directive 1999/31/EC of 26 April 1999 on the landfill of waste.

Directive 2006/12/EC of the EUROPEAN PARLIAMENT and of the COUNCIL of 5 April 2006 on waste.

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Directive 2008/98/EC of the EUROPEAN PARLIAMENT and of the COUNCIL of 19 November 2008 on waste and repealing certain Directives.

DECISIONS

Commission Decision of 3 May 2000 replacing Decision 94/3/EC establishing a list of wastes pursuant to Article 1(a) of Council Directive 75/442/EEC on waste and Council Decision 94/904/EC establishing a list of hazardous waste pursuant to Article 1(4) of Council Directive 91/689/EEC on hazardous waste.

Commission Decision of 16 January 2001 amending Decision 2000/532/EC as regards the list of wastes (notified under document number C(2001) 108).

Council Decision of 19 December 2002 establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16 of and Annex II to Directive 1999/31/EC.

3. ASSESSMENT OF BEST PRACTICES FOR UCO PROCESSING TO BIODIESEL

3.1 Quality characteristics of the collected UCO used for processing to biodiesel

Table 2 illustrates the physical and chemical properties of UCO collected in Shanghai, China.

Table 2. Physical and chemical properties of UCO (Wen et al, 2010)

Property Units Value

Palmitic acid wt% 8.5

Stearic acid wt% 3.1

Oleic acid wt% 21.2

Linoleic acid wt% 55.2

Linolenic acid wt% 5.9

Others wt% 4.2

Water content wt% 1.9

Density g/cm3 0.91

Kinematic viscosity (40 °C) mm2/s 4.2

Saponification value mgKOH/g 207

Acid value mgKOH/g 3.6

Iodine number g I2/100 g 83

Sodium content mg/kg 6.9

Peroxide value mg/kg 23.1

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The main difficulty in using UCO as a biodiesel resource is their content of impurities, such as Free Fatty Acid (FFA) and water. This makes necessary their treatment before the transesterification process due to their significant adverse effects on the process. The quality and the price of UCO are determined by their acid and saponification values. If the FFA content of the UCO is above 3.0% then significant problems may occur in the transesterification process.

Large amount of FFA in combination with moisture are leading to a large soap formation and hydrolysis respectively. The FFAs of UCO are sensitive to alkali catalyst and they must be removed before transesterification (Leung & Guo, 2006; Banerjee & Chakraborty, 2009). Both reactions mechanism are resulting in low biodiesel yield and in high catalyst consumption. To reduce the high FFA content in the oil, several techniques have been proposed:

acid esterification with methanol and sulphuric acid (Meng et al, 2008),

esterification with ion exchange resins (Ozbay et al, 2008),

neutralization with alkalis followed by soap separation by a decanter, and

extraction with polar liquids along with acid esterification and distillation of FFA.

To eliminate water content, UCO usually is heated to above 100°C (Demirbas, 2009). Alternatively, vacuum distillation at a 0.05 bar pressure is used (Felizardo et al, 2006). Furthermore, suspended solids, phospholipids, and other impurities can be washed away with hot water or removed by centrifugation and paper filtration (Chen et al, 2009).

3.2 Existing processing technologies and practices

Biodiesel obtained from renewable lipids, such as those of UCO, consists of long‐chain fatty acid

methyl esters (FAMEs). Biodiesel is highly biodegradable and has minimal toxicity; it can replace

petrodiesel fuel in many different applications including internal combustion engines without

major modifications. A small decrease in their performances is reported with almost zero

emissions of sulphates, aromatic compounds and other chemical substances that are destructive

to the environment. Technical problems facing biodiesel include low‐temperature properties,

storage stability and slightly increased NOx exhaust emissions. Marketing issues with biodiesel

include economics and the fact that there is only enough vegetable oil or fat available to replace a

few per cent of the petrodiesel market.

Transesterification is the most common method to produce biodiesel. Methanol is the normally

used alcohol in the process due to its low cost and physical and chemical advantages.

Homogeneous basic catalysts are the most widely used in industry as they accelerate the process

and achieve more mild reaction conditions. The reaction can be carried out either discontinuously

(batch) or continuously. After the reaction, the glycerol is separated by settling or centrifuging.

The biodiesel phase is then purified before being used as diesel fuel in compliance with the

EN14214 Standard and other national quality standards and technical norms.

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In Table 3, the advantages and disadvantages of the transesterification method are summarised,

as reported in relevant studies and research reports.

Table 3. Advantages and disadvantages of the transesterification method

PROCESSING METHOD ADVANTAGE DISADVANTAGE

Transesterification

Fuel properties are closer to diesel Low free fatty acid and water content

are required (for base catalyst)

High conversion efficiency

Pollutants are produced because

products must be neutralized and

washed

Low cost Accompanied by side reactions

Suitable for industrialized

production

In cases that UCOs are used as feedstock, more severe transesterification conditions are required compared to those of the normal process utilizing new oils. This is attributed to the fact that properties of UCOs are different from those of refined and crude oils. As the result of the high temperature during cooking and the water from the food, triglycerides in the oils are hydrolysed and this increases their free fatty acid (FFA) content. The FFA content is one of the important factors for alkali‐catalysed transesterification. This is due to the FFAs reacting with the alkaline catalyst to produce soap, which inhibits the reaction and the results in the reduction of biodiesel yield.

The following flowchart (Figure 4) indicates the main procedure stages, usually considered in the

biodiesel production process.

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Figure 4. Indicative flowchart of the biodiesel producing procedure

3.3 Common practices in transesterification

Transesterification is a relatively simple process that produces biodiesel (Fatty Acid Methyl Esters – FAME‐ and Fatty Acid Ethyl Esters – FAEE‐), according to the standards EN 14214 for Europe and ASTM D 6751‐12 for USA.

The most common processes are:

Classic transesterification process, Homogeneous ‐ catalyzed transesterification

Heterogeneous – catalyzed transesterification

Enzymatic, Enzyme ‐ catalyzed transesterification

Supercritical methanol, Non – catalyzed transesterification.

3.3.1. Homogeneous ‐ catalyzed transesterification

This is the most frequent process with the most commonly catalysts: potassium hydroxide (KOH) and sodium hydroxide (NaOH). Acid catalysts (Sulphuric acid ‐ H2SO4, Sulphonic acid ‐ RSO3H, Phosphoric acid ‐ H3PO4 and Hydrochloric acid ‐HCl) are used also with lower efficiency than the base catalysts.

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Base catalysts provide the additional advantage which of the lower cost. Additionally the FFA content in the base feedstock is essential for the process, because high FFA content needs additional amounts of catalyst and accelerates the soap formation through saponification. Figure 5 presents schematically the full alkali process of FAME from UCO.

In order to identify the best homogeneous catalysts for the esterification process of UCO, several studies have been reviewed. The majority, suggest to use of larger amount (excess) of Potassium Hydroxide. Others promote the use of methoxide catalysts as the lack of hydroxide radical in their structure reduces the amount of soaps by inhibition of the saponification reaction. Usually, they are referring to Potassium or to Sodium methoxide catalysts (Shimada et al, 2002; Georgogianni et al., 2009; Soriano et al, 2009; Thanh et al, 2010; Guzatto et al, 2011; Charoenchaitrakool & Thienmethangkoon, 2011; Yan et al, 2011).

Figure 5. Production of FAME from UCO by alkali process

3.3.2. Heterogeneous – catalyzed transesterification

Recently, a lot of researchers and industrial processes manufacturers have started to pay more attention to heterogeneous catalysts due to their higher biodiesel yield, higher glycerol purity and easier catalyst separation and recovery. Additionally, this process gains ground because it is being cheaper, safer, and more environmentally friendly; and not require a washing step for the crude ester. Moreover, heterogeneous catalysts are preferred over homogenous catalysts in biodiesel production from UCO because saponification and hydrolysis reactions are eliminated. The heterogeneous catalysts are separated, just like homogeneous catalysts, in two types: acidic and basic. Table 4 presents the “performance” of selective heterogeneous catalysts for the transesterification of UCO (Sakai et al, 2009; Agarwal et al, 2012).

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Table 4. Biodiesel production from UCO using heterogeneous catalysts

Oil Catalyst Catalyst

Amount (%wt)

Alcohol molar ratio

Process Ester yield (%) Temperature (°C) Time (h)

UCO

Sr/ZrO2 2.7 29:1 115.5 2.82 79.7

ZS/Si 3.0 6:1 200 10 81.0

SO42‐/TiO2–SiO2 3.0 9:1 200 5 92.0

3.3.3. Enzyme – catalyzed transesterification

This method includes the use of enzymes in the production of biodiesel. It must be noticed here that this method is not yet industrially available. Typical flowchart of enzymatic production of FAME is presenting in Error! Reference source not found..

Figure 6. Enzymatic production of FAME

The methods are presented in Figure 7 and compared in Tables 5 and 6.

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Figure 7. Comparison of steps involved in the immobilization of extracellular and intracellular lipase enzymes

The use of enzymes provides the advantage of the tolerance in the water concentration in the oil and the avoidance of FFA saponification. Additionally the reaction of transesterification can take place in lower pressure and temperature, thus leading in lower energy consumption. On the contrary, the enzyme has more expensive, there is inhibition by methanol, long reaction time is required and the glycerol is adsorbed on the enzyme surface (Hama et al., 2011; Talukder et al, 2011).

Table 5. Comparison of tasks in the enzymatic production of biodiesel for extracellular lipase (Ranganathan et al, 2008)

Developer /year Oil Enzyme Acyl

acceptor Conversion

(%) Technique employed

Cost of production

Watanabe et al (2000)

Vegetable oil Novozyme

435 Methanol 90–93

Stepwise addition of methanol

Moderate

Samukawa et al (2000)

Soyabean oil Novozyme

435 Methanol 97

Stepwise addition methanol and

preincubation of enzyme in methyl

oleate and soyabean oil

High

Iso et al (2001) Triolein P.

flourescens Butanol 90

Butanol was used as an acyl acceptor and no solvent was

used

Moderate

Shimada et al (2002)

UCO Novozyme

435 Methanol 90

Stepwise addition of methanol

Low

Bako et al (2002)

Sunflower oil Novozyme

435 Methanol 97

Stepwise addition of methanol and

removal of glycerol by dialysis

High

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acceptor Conversion


Cost of production

Du et al (2004) Soyabean oil Novozyme

435 Methyl acetate

92

A novel acyl acceptor, methyl acetate which had

no inhibitory effects was used

High

Xu et al (2004) Soyabean oil Novozyme

435 Methanol 98

Stepwise addition of methanol and

removal of glycerol using the solvent, iso‐propanol

High

Li et al (2006) Rapeseed oil

Novozyme 435 &

Lipozyme TL IM

Methanol 95

Combined use of Lipozyme TL IM

and Novozyme 435 along with tert‐

butanol as solvent

High

Royon et al (2007)

Cotton seed oil,

Novozyme 435

Methanol 97 tert‐Butanol was used as a solvent

High

Modi et al (2007)

Jatropha oil Novozyme

435 Ethyl

acetate 91.3

Ethyl acetate having no

inhibitory effects was used

High

Table 6. Comparison of works on enzymatic production of biodiesel for Intracellular lipase (Ranganathan et al, 2008)


acceptor Conversion


Cost of

production

Ban et al ( 2001) Vegetable oil Rhizopus oryzae

Methanol 90

Stepwise addition of methanol and application of

glutaraldehyde for stability of enzyme

Low

Hama et al (2007)

Soyabean oil Rhizopus oryzae

Methanol 90 Stepwise addition of methanol in a

packed bed reactor Low

3.3.4. Non – catalyzed transesterification

This, not yet industrial method uses methanol under supercritical conditions (Figure 8). The supercritical transesterification has some advantages over the conventional process due to the absence of catalyst, to the easier separation of products, to the faster reaction rate and to the elimination the effects of the high content of FFA and of the excess of water. However, the method requires high reaction temperature and pressure, as well as large excess of alcohol. As a result of the supercritical, the energy required is high and increased capital cost (Saka et al, 2010; Tan et al, 2010; Quesada‐Medina & Olivares‐Carrillo, 2011). Typical flowchart of the proposed procedure is presenting in Figure (van Kasteren & Nisworo, 2007).

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Figure 8. Supercritical transesterification process for UCO conversion to biodiesel

According to Table 7, the original optimal conditions ‐defined as yielding the highest extent of reaction as over 90% triglyceride conversion or over 96% alkyl esters content‐ were temperatures within 300 – 350oC, pressure within 20 – 35MPa, an alcohol to oil molar ratio of 40:1 – 42:1 and a reaction time of 5 – 30 min, for both methanol and ethanol (He et al, 2007). These parameters are referred as the original supercritical transesterification parameters, and have been employed to study the effects of each parameter, the chemical kinetics, the phase behavior and the techno‐economic feasibility of the process.

Among the general operating parameters mentioned above, the Reaction Temperature is the major determinant of reaction's efficiency. However, where maximum alkyl ester content is required, that is for biodiesel production, the higher operating temperatures cause a negative effect on the proportion of alkyl esters obtained in the product due to the thermal cracking reaction. Indeed, the thermal cracking is the chemical limitation of supercritical transesterification. Explaining the above limitations it must be mentioned that the European Standard EN14214, which requires over 96.5% esters content, thermal cracking of polyunsaturated fatty acids is a serious obstacle. According various studies the methyl linoleate content in FAME decreases by approximately 10% compared with the level in the feedstock if the reaction temperature is over 300oC and the reaction time over 15 minutes (Ngamprasertsith & Sawangkeaw, 2011). Additionally, the high temperature and pressure requires both expensive reactor and a sophisticated energy and safety management policy. The high alcohol to oil molar ratio has as result, large energy consumption, which is required in the reactants pre‐heating and in the recycling steps. The high amount of alcohol in the biodiesel product retards the biodiesel‐glycerol phase separation. Taking into account those original parameters results in high capital costs, especially for the reactor and pump, being somewhat higher than the novel catalytic methods. In order to increase the technical and economic feasibility of supercritical transesterification, further studies are required to optimize the operating parameters of this process.

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Table 7. Reaction parameters and optimal conditions of supercritical transesterification for various oil types and alcohols

Developer/Year

Oil type Alcohol

Temp. P (MPa)

Alcohol/oil

(mole/mole)

Reaction time (min)

Reactor

(size/type)

Extent of reaction

Bunyakiat

et al (2006)

Coconut & Palm kernel

Methanol, 350oC

19 42:1 7 ‐ 15

251‐mL

Continuous reaction in a tubular vesicle

95% Methyl Ester Content

Demirbas (2002)

Hazelnut kernel &

Cottonseed

Methanol, 350oC

Not Reported

41:1 5 100‐mL

Batch


Rathore & Madras (2007)

Palm and Groundnut

Methanol, 400oC

20 50:1 30 11‐mL

Batch

95% Triglyceride Conversion

Sawangkeaw et al (2007)

Palm kernel Methanol 350oC

20 42:1 30 250‐mL

Batch


Saka & Kusdiana (2001)

Rapeseed Methanol 350oC

45 42:1 4 5‐mL

Batch


Minami & Saka (2006)

Rapeseed Methanol 350oC

20 42:1 30

200‐mL Continuous reaction in a tubular vesicle


Yin et al (2008)

Soybean Methanol3

50oC 20 42:1 30 250‐mL Batch


Madras et al (2004)

Sunflower Methanol& Ethanol 400oC

20 40:1 30 8‐mL Batch 97%

Triglyceride Conversion

Vieitez et al (2011)

Castor Ethanol 300oC

20 40:1 Not

Reported


75% Ethyl esters content

Silva et al (2007)

Soybean Ethanol 350oC

20 40:1 15


80% Triglyceride Conversion

Balat (2008) Sunflower Ethanol 280oC

Not Reported

40:1 5 100‐mL Batch 80% Ethyl esters content

3.4 Comparative analysis of the most common practices

The production of biodiesel from UCO is expected to be more important in the future due to its low cost and wide availability. The following aspects must be taken into account.

First, UCO requires several pretreatment steps in order to eliminate solid impurities and to reduce FFA and water contents. The pre‐treatment process may include a washing step, centrifugation, flash evaporation, and acid esterification. Methanol is used in the transesterification process because of its wide availability, high activity and low cost. However, ethanol is more soluble in oil,

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which enhances mass transfer within the system. Thus, a methanol ‐ ethanol mixture was proposed to combine the advantages of both alcohols. Several types of catalysts have been used widely for esterification reaction, such as homogenous catalysts, heterogeneous catalysts, enzymes and supercritical esterification. For the production of biodiesel from UCO a challenge between Base homogenous and heterogeneous catalysts is established.

The basic advantages and disadvantages of the above processes are illustrated in Table 8. Table 8. Advantages and disadvantages of the transesterification processes

Process Advantages Disadvantages

Homogeneous ‐ catalyzed transesterification

Acceptable Reaction Time

Easy

Sensitive to FFA

Use of Water

Glycerol Quality

Heterogeneous – catalyzed transesterification

Not so Sensitive to FFA

Use of Water

Glycerol Quality

Expensive

Longer Reaction Time

Enzyme ‐ catalyzed transesterification


Use of Water

Glycerol Quality

Very Expensive

Longer Reaction Time

Supercritical Methanol


Use of Water

Glycerol Quality

Very Expensive

Use of Energy

3.5 Health and Safety

The production of UCO is a complex process, which is involving several reactions affecting the components; firstly the fatty material used as a frying medium which are the Triglycerides (TG), and secondly the components of the unsaponiable fraction (sterols, tocopherols, carotenes, etc.). Basically three types of reaction take places during the forming process. These are:

Oxidation reactions

Hydrolysis of triglycerides

Polymerization of triglycerides. The various products of these reactions may be grouped as in the Table 9.

Table 9. Results of frying

REACTION RESULTS

Oxidation reactions

Fixed oxidation compounds (oxidised TG, epoxides, etc.)

Volatiles (hexanal, pentane, 2,4‐decadienal, pentanol, etc.)

Oxidised oligomers

Sterol oxides

Hydrolysis of triglycerides

Free Fatty Acids (FFA)

Diglycerides (DG)

Monoglycerides (MG)

Polymerization of triglycerides Non‐polar dimers

Other non‐polar oligomers

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The main characteristics of UCOs in relation to their safety are (Riera & Codony, 2000):

Transfer of liposoluble compounds in the food to the frying oil; it allows the liposoluble contaminants in the food to be transferred to the cooking oil. It should also be pointed out that as successive batches of food are placed in the oil, these substances will become concentrated.

Transfer of water from the food to the frying oil; this is a determinant of its degradation reactions. It is also important to consider the remaining water concentration in UCOs collected for subsequent recycling.

Formation of volatile compounds in the oil, at low concentrations; they are giving the typical aromas and flavors in the fried products, but in high concentrations are undesirable.

Considerable degradation in composition of the cooking oil, as a result of different reactions. Because of its importance regarding safety of use in feeds, this is discussed.

The main harmful effects of the oil’s degradation compounds are presenting in the table 10 below:

Table 10. Harmful effects of the oil’s degradation compounds

Degradation compounds Severity Toxic effects

Hydroperoxides Low, only at low temperatures

Enzymatic dysfunction of the intestinal mucosa

Induction of colon cellular proliferation

Epoxides, TG and Oxidized FAcids Moderate (low temp.) Hepatic hypertrophy.

Hepatic enzymatic dysfunction

Secondary compounds Moderate‐High Hepatoxicity

Mutagenicity

Oxidised cyclic monomers Moderate‐Low especially at high

temperature Reduced growth and death

Non‐oxidised dimers and

oligomers

Moderate‐High at 200°C and low oxygen concentration

Diarrhea

Oxidised dimers Predominant at high temperature

with excess of oxygen Reduced growth

Oxidised oligomers Predominant at high temperature

with excess of oxygen Reduced growth

Oxysterols Variable Atherogenicity.

Cytotoxicity/Mutagenicity

It is obvious that these compounds show toxic effects, so the established toxicity value is the sum of all the substances present in a sample. The UCOs can be toxic, so they must be handled as those.

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4. HARMONIZATION WITH THE EU DIRECTIVE FOR SUSTAINABILITY

The exploitation of UCO to biodiesel is in line with the Renewable Energy Directive (RED), covering

Green House Gas emissions, biodiversity and carbon stock. UCO and tallow (excluding category 3

tallow) use the EC default value for ‘waste vegetable and animal oil’. For the use of the UCOs in

the FAME production the carbon intensity is 14 grCO2eq/MJ and the Carbon Saving is 83%.

The materials most commonly used for biofuel production are UCO, animal fats of categories I and

II1, followed at some distance by crude glycerin. Added up, an estimated total of up to 1 ‐ 1.5

MTonnes of these three feedstocks are currently used and some 6.1 MTonnes might potentially be

available in the EU at 2020, although the retrievable potential of UCO is unlikely to be totally

collected. It can be concluded that the available UCO, animal fats and crude glycerin are

insufficiently available to produce the quantity of 7 Mtoe of advanced biofuels required in 2020,

even taking into account the quadruple counting of crude glycerin. Unless the proposed measures

lead unexpectedly to a surge in cellulosic ethanol production, it is unlikely that sufficient advanced

biofuels can be produced from EU feedstocks to meet the RED target. This means that a certain

degree of feedstock imports will be necessary (Peters et al, 2013). Consequently, this arise the

prices of UCO and animal fats prices as it happened in recent past years. EU has to face the threat

of the cheap imported UCO and animal fats.

Additionally, the impact on the biofuel price is estimated to be limited since sufficient relatively

cheap double and quadruple counting biofuels are available today. To ensure a robust

implementation, the full supply chain needs to check the origin of the feedstock to guarantee its

quality. In other words, the full chain needs to start checking from the place of production of the

feedstock. For UCO, the full chain inspection is required to include verified evidence from the

actual restaurant or food processor. In cases where feedstocks are generated at many locations

prior to their collection, such as restaurants, the approach might not be very practically realistic.

This could be partly solved by applying a certain annual sample size, meaning that every year a

small percentage of the chain will be actually checked. This is how the German audit requirements

for double counting materials work and it remains to be seen how much UCO will be supplied to

the German market in the future. For UCO, the first point to be audited in the supply chain could

be the first collector of the material (Peters et al, 2013).

With reference to the EU Directive there are points where the production of FAME and biofuel in

general is not completely addressed. This explained in detail below:

The statement “Current incentives, particularly, those set out in Article 21(2) of the RED,

are not enough to spur the desired level of investment in advanced 2nd generation

biofuels” is partially addressed. This happened because the figures on biofuel deployment

in the period 2009‐2011 shown a significant increase in advanced biofuel production in the

EU, mainly UCOME and animal fat based biodiesel. At the same time, investments in

cellulosic ethanol increased only slightly. Double counting therefore proved to be effective

1Category I animal fats: animal fat, max. 15 % FFA; also animal fat, max. 15 % FFA, purified to max. 0.15% impurities

Category II animal fats: animal fat, max. 15 % FFA

20

in stimulating production and supply of low‐tech double counting biodiesel whereas it did

not spur investments in high‐tech advanced biofuels.

The statement “the availability of biofuels made from waste, residues, non‐food cellulosic

material and ligno‐cellulosic material" (article 23) is a question of supply, both in terms of

availability of raw‐material e.g. waste oil, but also a technical question whether enough

production capacity can be cost‐efficiently installed by 2020. Achieving a supply of 3.8

Mtoe of double counted biodiesel would therefore be challenging is partially addressed.

This happened because the term “advanced biofuels” can lead to confusion. It seems to be

defined by the Commission as biofuels produced from waste, residues and cellulose. While

the uptake of cellulosic biofuel capacity is technically challenging, the availability of

sufficient capacity of biofuels produced from wastes and residues does not pose a

technical challenge. Esterification plants could be converted to process waste/residue

feedstocks such as UCO or waste animal fat. This requires a high investment. Sufficient

capacity is available in the EU which could be used for advanced biofuel production,

although retrofitting capacity which is integrated with crushing capacity might be

challenging. Supply of double counting feedstocks in a sustainable way could be

challenging.

5. CLIMATE AND GEOGRAPHICAL PARAMETERS

A lot of FAME producers from vegetable oils can switch to producing UCO based biodiesel.

Switching from FAME to UCO Methyl Esters could require a substantial investment depending on

the quality of UCO which is used. High quality UCO with little impurities and a low content of FFAs

could be used without problems in FAME installations (European Biodiesel Board, 2013).

However, according to the quality of available UCO, an investment at the biodiesel facility may be

required even if the esterification process remains the same. Such a retrofit could include pre‐

treatment (filtering) of the UCO and building UCO storage tanks. It requires the installation of an

esterification unit at the beginning of the process, and a distillation unit at the end, to make sure

that the biodiesel still meets the European EN 14214 standard for biodiesel. These additional units

reduce the conversion efficiency of the installation.

Such an investment typically cost 2.5‐5.5 Μ€ for 50% of a 100,000 tons installation, meaning

between 33% ‐ 50% of the initial biodiesel plant investment costs (Peters et al, 2013). Shifting from

FAME to Used Cooking Oil Methyl Esters (UCOME) is more suitable for stand‐alone biodiesel plants

and less suitable for plants which are integrated with oilseed crushers. An investment in

retrofitting is especially interesting for investors who buy a biodiesel installation who went

bankrupt, for a modest sum of money. As feedstock processors are and biodiesel producers, they

have some flexibility to shift to non‐conventional biofuel or non‐biofuel markets. However, since

the market is not expected to increase up to 2020 is not estimated that the short‐ and mid‐term

utilization of the capacity will be enlarged. The use of the alternative esterification methods must

be examined in order to improve the economic results of a retrofit.

21

The climate and geographical parameters are playing an important role in the production of

methyl esters from UCO. Basically, they influence the quality parameters of the produced UCO

indirectly; they influence the quality of the produced virgin vegetable oil, so the properties of

UCOs are affected. The concentration of FFA in the oil has a main impact (Fieldsend & Morison,

2000). Additionally, many researchers have proved that seed yield was significantly influenced by

the harvest time, even in autumn season only. The longer growing period of plants influences also

the yield of seeds. The higher temperature and higher precipitation rate that prevailed during seed

ripening are producing high seed yield and oil quality. Even the harvest technique, in some cases,

tended to influence the seed yield, plant dry matter, seed dry matter, oil content, stearic acid,

oleic acid and linoleic acid (Ghasemnezhad & Honermeier, 2007).

All the above parameters may influence important properties of the produced FAME. These

properties are critical for the oxidation stability of the produced FAME. At first, the Iodine Value

or either called Iodine Number (Iodine Value is a stability index measuring level of unsaturation in

organic compounds, such as FAME), which is an indicator of the number of double bonds which

are present in the sample. The higher the Iodine Value, the higher the number of double bonds.

The Iodine Value decreases with higher alcohols used in transesterification. Iodine Value is one of

the oldest and most common methods for determining the level of unsaturation in a fatty oil or

ester (Pullen & Saeed, 2012). Additionally the content of methyl linolenate is restricted in EN

14214 because of its high propensity to oxidize. However, the 12% limit is set so as not to exclude

high oleic rapeseed oil, which is one of the major European biodiesel feedstocks (Knothe, 2006).

FAME or ester content diminishes as esters degrade by oxidation, so that this measurement can

serve to indicate oxidation progress (Lacoste & Lagardere, 2003).

Additionally, the quantity of fatty acids and mineral acids influence the acid number of the

biodiesel fuel. High fuel acidity is associated with corrosion and engine deposits, particularly in the

fuel injectors. Di‐ and tri‐ unsaturated fatty acids contain the most reactive bis‐allylic sites for

initiating the autoxidation chain reaction (Pullen & Saeed, 2012).

Oxidation stability was reported to correlate not with the total number of double bonds, but with

the total number of bis‐allylic sites. Vegetable oils rich in polyunsaturated linoleic and linolenic

acids, therefore tend to give methyl ester fuels with poor oxidation stability (Ramos et al, 2009).

Oxidation products can attack elastomers, clog fuel filters and contaminate engine lubricating oil.

Corrosive acids and deposits may cause increased engine wear. Blending biodiesel with petro‐

diesel can exacerbate insoluble formation. Oxidation of biodiesel can only be delayed and not

completely prevented. Delaying techniques include control of fatty acids composition and storage

conditions among other procedures.

22

6. ENVIRONMENTAL PERFORMANCE AND IMPACTS ANALYSIS

The current integrated management of UCOs is presented in Figure (Peiro et al, 2010).

Figure 9. Overall production of FAME from UCO

The environmental impact of 1 ton biodiesel production from UCO has the following impacts to the following ten (10) categories as depicted in Table 11 (Peiro et al, 2010).

23

Table 11. The environmental impact of 1 ton biodiesel production from UCO

Impact Categories Contribution of the UCO

Collection (%)

Contribution of UCO Pre‐

treatment (%)

Contribution of UCO

Delivery (%)

Contribution of Transesterification

(%)

Total impact

Units

Abiotic Depletion 0 10 0 90 5.51 kg Sb eq

Global Warming Potential

0 25 0 75 299.60 kg CO2 eq

Ozone Layer Depletion

0 29 0 71 5.80 x 10‐5 kg CFC 11 eq

Human Toxicity 0 34 0 66 106.97 kg 1,4

dichlorobenzene eq

Fresh Water Aquatic Ecotoxicity

0 27 0 73 19.18 kg 1,4

dichlorobenzene eq

Marine Aquatic Ecotoxicity

0 60 0 40 1.39 x 105

kg 1,4 dichlorobenzene

eq

Terrestrial Ecotoxicity

0 30 0 70 0.52 kg 1,4

dichlorobenzene eq

Photochemical Oxidation

0 25 0 75 0.08 kg C2H4 eq

Acidification 0 43 0 57 1.39 kg SO2 eq

Eutrophication 0 37 0 63 0.10 kg PO4 eq

In relevance to the commitments for increasing the share of renewables in the electricity generation, the ecological footprint of FAME production from UCO presents a significant decrease (Table 12) as the electricity consumption in the manufacturing process is becoming more green. The impact in the marine aquatic ecotoxicity decreased 35.54%. The only increment in the environmental impact referring to the Ozone layer depletion and the percentage is 0.17%. Table 12. Environmental impact of 1 ton of FAME from UCO for 2006 and 2010 in Spain

Impact Categories 2006 2010 Difference (%) Units

Abiotic Depletion 5.51 5.34 ‐3.08 kg Sb eq

Global Warming Potential 299.60 275.61 ‐8.01 kg CO2 eq

Ozone Layer Depletion 5.80 x 10‐5 5.81 x 10‐5 0.17 kg CFC 11 eq

Human Toxicity 106.97 97.28 ‐9.06 kg 1,4 dichlorobenzene eq

Fresh Water Aquatic Ecotoxicity

19.18 17.10 ‐10.84 kg 1,4 dichlorobenzene eq

Marine Aquatic Ecotoxicity 1.39 x 105 8.96 x 104 ‐35.54 kg 1,4 dichlorobenzene eq

Terrestrial Ecotoxicity 0.52 0.43 ‐17.31 kg 1,4 dichlorobenzene eq

Photochemical Oxidation 0.08 0.07 ‐12.50 kg C2H4 eq

Acidification 1.39 1.05 ‐24.46 kg SO2 eq

Eutrophication 0.10 0.08 ‐20.00 kg PO4 eq

24

The BIOSIRE project summarizes the LCA analysis for the Rapeseed Methyl Ester (RME) produced. It was mentioned that RME biodiesel has a mean CO2 equivalent saving of 2.7kg for every kg of substituted fossil fuel. At the same report it is mentioned that FAME made from sunflower or soybean oil has even greater savings of CO2 equivalent due to the need for less nitrogen derived fertilisers. A typical LCA assessment for RME according to the BIOSIRE project is summarized in Table 13 (Roy, 2009). Table 13. LCA assessment for RME (BIOSIRE project)

Balanced Category General assessment Ecological relevance

Demand for mineral resources Disadvantage Disadvantage

Demand for finite energy Advantage High

Global warming potential Advantage Very high

Acidification potential Disadvantage Medium

Eutrophication potential Disadvantage Medium

Stratospheric ozone depletion Disadvantage High/Very High

Tropospheric ozone formation potential

Difference of less

than 10% Disadvantage

Human and Ecotoxicity biodegradability

Advantage Medium

Table 14 compares the four main transesterification processes:

Homogeneous ‐ catalyzed transesterification.

Heterogeneous – catalyzed transesterification.

Enzyme ‐ catalyzed transesterification.


The evaluation criteria are:

Environmental

Technical

Health & Safety

Market Opportunities & Barriers

Harmonization with EU Directive & Sustainability

Climate / Geographical Parameters

25

Table 14. Evaluation criteria of examined biodiesel production processes

EVALUATION CRITERIA

Process Environmental Technical Health & Safety

Market Opportunities & Barriers

Harmonization with EU

Directive & Sustainability

Climate / Geographical Parameters

Homogeneous ‐ catalyzed

transesterification

Waste Water and Saponified Products

Poor quality of glycerin.

Established Technology

Normal

Increasing Market Share.

Low Quality

Covering the EU Directive on Sustainability

High dependent

Heterogeneous – catalyzed

transesterification

No waste water.

Low to normal glycerin purity.

Longer Time

Reaction Normal

High Costs

Increased production of Methylesters


High dependent

Enzyme ‐ catalyzed transesterification.

No waste water.

Normal or triacetylglycerol as

byproduct

Normal

High Costs.

Increased Production of Methylesters.

High reaction time


Moderate


No waste water.

Higher impact on the environment, because of its requirement for large amounts of methanol during the reaction and consequently the

energy expenditure in methanol

recirculation in the recycle loop.

Large amounts of energy.

High glycerin purity

High

High Costs

Increased Production of Methylesters.

Large amounts of energy.

Not proved industrial production.


Moderate

The supercritical process always generated a higher impact on the environment, because of the requirement for large amounts of methanol during the reaction and consequently the energy expenditure in methanol recirculation. In order to make the supercritical methanol process feasible, from the environmental point of view, the distillation column in the methanol recovery process has to be replaced with a different less energy‐intensive process technology. Alternatively, it remains to be confirmed if the promising results of the two‐stage supercritical process, with reduced operating pressure, temperature and methanol to oil ratios, will be reliably translated into industrial scale production (Kiwjaroun et al, 2009).

Obviously acid, alkali, or enzymatic catalyzed and supercritical transesterification are alternative approaches that have been used for biodiesel production. However, all of them have advantages and disadvantages. The type of feed stock is the most important factor in the production of biodiesel. It is important to understand that UCO can decrease biodiesel production costs. On the

26

other hand, the shortage of UCO in EU may lead in imports so the price of obtaining the raw material may be higher than it is today. However, the cooking process has negative influences on oil properties and can create different types of impurities in the oil and can also increase the FFA and water content of oil. Therefore, these obstacles increase the cost for the purification and separation process in the downstream biodiesel production.

The transesterification with alkali catalysts is the conventional method for biodiesel production, but this method causes serious problems in the purification part since they are highly sensitive to FFA and water content in the UCO. The acid catalyzed process is not sensitive to FFA and water content like base catalysts. However, the production process is much longer.

The utilization of enzymatic catalysts showed very promising results, but they are expensive, so this is not suitable for industrial production of biodiesel (Kiakalaieh et al, 2013). Furthermore, the supercritical method requires high temperature and pressure, making the process, yet, not economical and not environmental friendly.

Therefore, scientists focus on the utilization of heterogeneous acid and base catalysts in biodiesel production since the catalysts may be reusable many times. The reuse of catalyst is an environmental friendly practice. The reusability of catalyst is the most important property which can make them economical for industrial production in a continuous process. Hence, various methods such as membrane reactor, reactive distillation, reactive absorption, microwave, and ultrasonic to reduce production costs, reaction time, catalyst and alcohol requirements have been used in transesterification reactions. These methods are trying to increase the quality and quantity of FAME for applications to diesel engines without any kind of engine modification.

Being realistic, for the current time the use of homogenous catalysts is the optimum way of producing biodiesel from UCO. The following considerations must be taken into account:

KOH catalyst is less effective than the sodium based catalysts. A catalyst concentration of 0.8 (wt%) for UCOs ensures that viscosity is within the limits, but then purity is lower than the minimum required according to the European biodiesel standard EN 14214. Because at the highest catalyst concentrations purity was generally very close to the limit, best results would be expected by increasing the catalyst concentration (Dias et al, 2008; Atapour et al, 2013).

Kinematic viscosity and methyl ester content are the most important properties to evaluate which catalyst type and concentration are needed.

Methanol, being cheaper, is the commonly used alcohol during transesterification reaction.

27

7. DISTRIBUTION PRACTICES

Biodiesel distribution involves the steps and provisions required to transfer the biodiesel from the

producer into the marketplace or into the refinery for blending. This includes the storage

infrastructure, the blending techniques, the quality assurance and transportation methods and

means.

Figure 10 indicates the stages which should be considered in the biodiesel distribution process.

Figure10. Indicative flowchart of the biodiesel distribution steps

Due mainly to taxing reasons there are specific strict rules for the distribution practices per

country. An indicative picture of the end users in RecOil countries is presented in Table 15.

Table 15. Potential customers of the biodiesel production plants

Country End Users/Destination

Greece Refineries

Distributor

Denmark Refineries

Distributor

Portugal

Refineries

Distributor

End Users (Transport Companies)

Italy Refineries, Distributor

Spain

Refineries

Distributor

End Users (Transport Companies)

Gas Stations

28

A comparison of the three main distribution methods is presented in the Table 16.

Table 16. Assessment of the biodiesel distribution methods

Destination Advantages Disadvantages

Refineries Constant buyer

More constant rules

Oligopsony controlling the market

Distributor Selection of the best prices and trade agreements

Sensitive market depending on national policies

Transport Companies and Gas Stations

Selection of the best prices and trade agreements

Risk for black market and tax evasion

8. CONCLUSIONS

UCO full chain is a dynamic business activity in EU with essential economic and environmental benefits. The analysis of the current report reviewed the best methods to process the UCO‐to‐biodiesel chain putting emphasis on the most critical technical and practical guidelines including best practices, quality characteristics of the collected UCO, potential implications, Environmental performance and Risks. This analysis was based on:

the existing know‐how and experience of the members of the consortium

reviews with the real market stakeholders

important S&T literature.

29

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33

10. ABBREVIATIONS

ASTM : American Society for Testing and Materials

BHT : Butylated hydroxyl‐toluene

BIOSIRE : BIOSIRE Creating Sustainable Transport in Tourism Regions

CEN : European Committee for Standardization

CFPP : Cold Filter Plugging Point

CONCAWE : CONservation of Clean Air and Water in Europe

FAEE : Fatty Acid Ethyl Ester

FAME : Fatty Acid Methy Ester

FFA : Free Fatty Acid

HCl : Hydrochloric acid

H3PO4 : Phosphoric acid

H2SO4 : Sulphuric acid

IV : Iodine Value

KOH : Potassium Hydroxide

NaOH : Sodium Hydroxide

PME : Palmseed Methyl Ester

RME : Rapeseed Methyl Ester

RSO3H : Sulphonic acid

Sr : Strontium

Si : Silicon

SiO2 : Silicon dioxide

SO42‐ : Sulfate

TG : Triglycerides

Ti : Titanium

TR : Technical Regulation

UCO : Used Cooking Oils

UCOME : Used Cooking Oil Methyl Esters

UK : United Kingdom

ULSD : Ultra Low Sulfur Diesel

WP : Work Package

ZrO2 : Zirconium dioxide

34

RecOi l Partnership

Energy and Environment Agency of Arrábida (coordinator)

Factor Social

Technical University of Crete

Local Energy Agency Province of Cosenza

Energy Management Agency Province of Cádi z

Regional Energy Agency for Barreiro, Moita, Montijo and Alcochete

Elin Biofuels S.A.

Energy, Transport, Agriculture SRL

Municipality of Castrolibero

European Biomass Industry Association

Agro Business Park.


35

Energy and Environment Agency of Arrábida, Factor Social, Technical University of Crete, Local Energy Agency Province of Cosenza, Energy Management Agency Province of Cádiz, Regional Energy Agency for Barreiro, Moita, Montijo and Alcochete, Elin Biofuels S.A., Energy, Transport, Agriculture SRL, Municipality of Castrolibero, European Biomass Industry Association, Agro Business Park.


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