Descripciones de los casos de usos del negocio

By J. van Eijck (UU)

This section includes only a small portion of the technical articles and reports that have been published. We have identified only those topics that are directly relevant to the use of seedcake as fertilizer vs fuel. We have only looked at

published reports that mention practical problems or solutions. See ANNEX IV for a table rating 16 studies. More technical studies can be found on:

https://jatropha.uni-hohenheim.de/64545.html.

We discuss seedcake and processing.

8.1 Seedcake

Jatropha seedcake is the residue left after oil has been pressed out of Jatropha seeds. On average ⅔ of the seed weight remains as seedcake, and the other ⅓ is oil. The seedcake still contains some oil, the amount being dependent on the efficiency of the extraction process; the review by Achten et al. mentions a 9-12%

oil content by weight on average (Achten et al. 2008). There are different options for the use of seedcake. The most suitable use is determined by specific local factors such as the distance to places where it can be used, market conditions, and economic feasibility. In Tanzania for example seedcake is made into briquettes, charcoal and biogas (van Eijck 2009).

8.1.1 Fertilizer

There is some discussion about whether it is better for the GHG balance to use the seedcake as fertiliser (thereby closing the nutrient cycle and reducing the need for artificial fertiliser which has high GHG emissions) or to use the seedcake as fuel (thereby making optimum use of the energy content of 18.2 MJ/kg).

Many studies describe the potential value of Jatropha seedcake as fertilizer. The exact composition of the seedcake varies per batch but Achten et al. have found a range of 3.8‐6.4% by wt of nitrogen, : 0.9‐2.8% by wt of phosphorus, and 0.9‐1.8% by wt of potassium in the literature. Studies like Tigere et al. (2006) and Wani et al (2006) mention specific contents that fall within these ranges for seedcake from Zimbabwe and India, and also (Reinhardt et al. 2008) in their Basic Data on Jatropha have values in line with this. The Jatropha handbook by the FACT Foundation reports that the seedcake also contains trace amounts of calcium, magnesium, sulphur, zinc, iron, copper, manganese and sodium.

According to the handbook, one ton of seedcake is equivalent to 153 kg of NPK industrial fertilizer (15:15:15), on the basis of the nitrogen content (FACT Foundation 2009). Furthermore, Achten et al. found the average crude protein content of the seed cake to be 58.1% by weight (Achten et al. 2008).

This means that, as mentioned by many studies, in theory Jatropha seedcake has good fertiliser properties . However, very few studies describe the effectiveness of Jatropha seedcake as fertiliser in practice. Only three studies in our review

mention some practical experience; Wani et al (2006), Tigere et al. (2006) and Achten et al. (2008). However, of the four case studies in Achten et al., one is similar to Wani et al.. The results of the Achten et al. case studies are summarised in Table 8.

Table 8.1: Results Jatropha seedcake application as fertiliser, table from Achten et al., 2008

The results of these case studies indicate a high potential for using Jatropha seedcake as fertiliser. However the studies are outdated and no more recent studies were found. Only (FACT Foundation 2009) mentions that the seedcake should be composted before application, but there are no studies done to verify this. The economic value of the cake, its acceptability to local people as fertiliser as well as their willingness to pay for it are also unclear.

8.1.2 Fuel

Figure 8.1: Jatropha seedcake briquettes to be used as fuel (pic J. van Eijck)

No reports have been found that describe problems with using seedcake as fuel.

Technical data are available on the energy content (Kerkhof 2007) and (Achten et al. 2008). Achten et al. found an average gross energy content of 18.2 MJ kg⁻¹.

Country Crop Dosage (t per ha) Remarks

Mali1 Pearl millet 5 46% yield increase in

comparison to zero-input

Zimbabwe2 Cabbage 2.5-10 • 40–113% yield increase in

comparison to zero-input• Free from pest and disease, while cutworm infestation occurred with cow manure application

Nepal3 Rice 10 11% yield increase in

comparison to zero-input

India4 Jatropha 0.75-3 13–120% yield increase in

comparison to zero-input 1 : R. Henning, F. Samaké and I. Thiéro, La valeur fertilisante du tourteau du pourghère,

Projet Pourghère DNHE-GTZ, Bamako, Mali (1995).

2: (Ngoma 1999)

3: Heller J. Physic nut. PhD dissertation, Institute of Plant Genetic and Crop Plant Research, Gatersleben, Germany, and International Plant Genetic Resource Institute, Rome, Italy, 1996 http://www.ipgri.cgiar.org/Publications/pdf/161.pdf

4: A. Ghosh, J.S. Patolia, D.R. Chaudhary, J. Chikara, S.N. Rao and D. Kumar et al., Response of Jatropha curcas under different spacing to Jatropha de-oiled cake, FACT seminar on Jatropha curcas L. agronomy and genetics, Wageningen, The Netherlands, March 26–28, FACT Foundation, Wageningen (2007) Article no. 8.

8.1.3 Conclusions and recommendations

Conclusions:

• Jatropha seedcake has good fertilizer value (no reports were found that claim the opposite). It contains 4-6 % nitrogen, 1-3% phosphorous and 1-2%

potassium.

• The energy content of the seedcake is around 18 MJ/kg

• Hardly any data are available about impacts and practical applications

• The market, economic feasibility and possible adoption by local population are unclear.

• There is unresolved discussion about whether it is preferable to use seedcake as fertilizer or as fuel.

• Hardly any data are available on the use of processes such as pyrolisis and charring.

• Only technical feasibility of detoxification to make seedcake suitable for animal feed has been researched.

Recommendations:

• More experiments are needed with the application of seedcake as fertilizer, taking possible issues with adoption by the local population into account.

• Market analysis and economic feasibility need to be undertaken.

8.2 Processing

Several studies mention that there are different possibilities for extracting Jatropha oil from the seeds. An overview is given by (Achten et al. 2008) while more technical details are discussed by (Beerens 2007). The different aspects are combined in the Jatropha handbook of the FACT Foundation (2009). The options are manual pressing, mechanical pressing and chemical extraction. Reports on practical issues related to chemical extraction are missing. This might partly be due to the fact that many Jatropha projects have started fairly recently and the seed volumes are still too limited to start chemical processing yet.

8.2.1 Hand pressing

Two reports describe problems experienced with manual presses. In Mozambique the use of a hand press was problematic due to clogging and slow production (less than one litre per hour) (Nielsen and de Jongh 2009). These authors also stated that quality control of the oil is only feasible with a centralised oil production facility. In Zimbabwe, where hand operated ram presses are also used, 90 kg of seeds were found to yield 15-18 litres of oil (5-6 kg per litre) which is a rather low productivity (Tigere et al. 2006).

8.2.2 Mechanical pressing

Three reports describe projects that were involved in processing by means of mechanical extraction; in Tanzania (van Eijck 2009, and some economic data by (Messemaker 2008), in Mozambique (Nielsen and de Jongh 2009) and in Honduras (Moers 2010).

The optimum equipment for processing depends on the expected volumes , and the required quality. For these reasons, Diligent in Tanzania tested different types of equipment. However, it is also important that the workers who have to operate the machines have certain skills; with the required skill level varying with the type of equipment (van Eijck 2009). In Honduras it was learnt that existing processing technologies could be adapted for Jatropha. This means that equipment could be repaired (and manufactured) locally, in places where the necessary technical

capacity was present, e.g. at a technical school which is often found in a provincial capital city. Theauthor of the Honduran study concludes that this could be a selection criterion for choosing the headquarters of a Jatropha promotion project (Moers 2010). In the case of Diligent, the more advanced presses that were obtained from Europe required spare parts that could not be locally repaired, this can slow down the processing.

Furthermore in Mozambique it was observed that in local communities a press is not always kept in good condition. “Limited availability of Jatropha seeds is preventing optimal use of the press, which is therefore not well maintained and in bad condition“ (Schut et al. 2010b) p 81. See also the text box on Multi Functional Platforms in Section 5.2 on local prosperity.

8.2.3 Chemical extraction

Several studies have been published about the technical feasibility of chemical extraction, but all are still laboratory scale tests. Some of them are:

(Lim et al. 2010): New extraction method with methanol, only 80 minutes required

(Qian et al. 2010): Two-phase solvent extraction

(Balat and Balat 2010): Dilution, micro-emulsification, pyrolysis, and transesterification

No reports were found which report data from practical experiments.

8.2.4 Further processing

The processing steps after pressing, such as sedimentation, filtration etc. are described in the FACT handbook, which combines lessons from Honduras and Diligent in Tanzania, and lists various types of equipment for filtration and so on.

Jatropha oil contains a high amount of sediment, therefore filters clog up easily and rapidly, especially with oil filters under pressure (FACT Foundation 2009).

Prior sedimentation is therefore required. The production of biodiesel (which requires transesterification of the SVO) is described in the handbook as well, but no data have been reported about practical implementation issues. Theoretical studies and those based on with tests on laboratory scale are available. Some of them mention enzymatic transesterification, this has several advantages over alkali catalysis, namely “reducing process operations in biodiesel fuel production and an easy separation of the glycerol byproduct” (Fukuda et al. 2008; Rakshit et al. 2008). But until now the price of the lipase enzyme has been the main obstacle for commercially feasible production. Various other problems can also be expected to occur in the transesterification step, such as, lack of availability of methanol, problems with the quality of the biofuel, insufficient technical skills of operator, and problems with finding a suitable use of byproducts such as glycerine, and so on.

8.2.5 Conclusions and recommendations

Conclusions:

• No practical data are available about chemical extraction.

• Manual presses are considered to be slow and inefficient.

• If local equipment can be adapted for Jatropha seed pressing, equipment can be repaired more easily and faster than imported equipment.

• Technical skills are required by the operators of mechanical presses, technical training capacity is needed. The more advanced the equipment, the more training is required.

• Maintenance of the equipment in rural areas might be problematic.

• There are no data on biodiesel production in practice, e.g. about the use of glycerine and other byproducts, and about the quality of biodiesel produced.

Recommendations:

• More research on various aspects is required, both in lab setting and in pilot or experimental set ups.