Category Archives: Microbes and biochemistry of gas fermentation

Conclusion and future directions

Microwave irradiation was applied to syntheses of ETBE from biomass-deriveable alcohols (TBA and EtOH). The maximum yield obtained under atmospheric conditions was low at around 30%, which agreed with our previous studies on reactive distillation and the results obtained by other researchers. Performing the experiments in a sealed reactor at a micro­wave power of 350W, and irradiation time of 1 min, the mixture reached pressurized condi­tions obtaining EtOH conversion closed to 90%. The conversion and yield were found to be also dependent on operating parameters such as temperature, microwave irradiation power, time and amount of catalysts. Preliminary studies on combined reaction and separation process inside the cavity showed promising results but need further investigation for con­trol and optimization of its operation.

The application of microwave irradiation to the synthesis of this promising biofuel offer benefits including energy efficiency, development of a compact process, rapid heating and instant on-off process (instant heating-cooling process), among others. Unlike the conven­tional heating, the heat is generated within the material, thus rapid heating occurs. Besides, microwave effects on reaction also likely occur, thus obtaining dramatic increase in the yield even at low bulk temperatures.

The benefits have been indicated by the above mentioned results. However, there are some drawbacks including the problems with non-homogeneous heating that would require thor­ough investigation prior to its commercialization. Although the field is in its infancy, the outlook is bright for the proposed methods due to foreseen high global demands for bio­fuels. The next few years should see development of continuous compact process, along with cheap, effective and stable solid catalysts.

As the demand for biofuels continue to increase in the near future, and while the search for an efficient and low-cost production process continues, the global outlook is positive for the use of microwave irradiation to the synthesis of ETBE. To overcome the limitations for scal­ing up microwave-assisted technology for ETBE production, development of a compact con­tinuous process is suggested, but still poses several challenges that require detailed investigation. The future also calls for the development of cheap, effective and stable solid catalysts for the synthesis of the abovementioned fuels. While the use of microwave irradia­tion offers great benefits with regards to rapid reaction or synthesis, safety is a big factor to consider in designing a large scale production plant. However, this can be avoided if multi­layered compact reactors operating under microwave irradiation can be developed instead.

Acknowledgments

Most of the research works were supported financially by the Japan Science and Technology carried out at the Research Institute for Solvothermal Technology, Kagawa Industry Support Fundation. The MARS 5 apparatus was donated by AIST-Shikoku through the kindness of Dr. Akinari Sonoda. This work was also partly supported by Kumamoto University Global COE Program "Global Initiative Center for Pulsed Power Engineering".

Author details

Armando T. Quitain1, Shunsaku Katoh2 and Motonobu Goto2

1 Graduate School of Science and Technology, Kumamoto University, Japan

2 RIST Kagawa, Kagawa Industry Support Foundation, Japan Department of Chemical Engineering, Nagoya University, Japan

Biodiesel extraction methods

З.1.2.1. One step transesterification

For the synthesis of biodiesel, the following materials were used: oil sample (FFM Sdn Bhd), methanol (Merck 99%), and potassium hydroxide (KOH) as a catalyst (HMGM Chemicals >98%). Methanol and potassium hydroxide were pre-mixed to prepare potassium methox — ide, and then added to oil in the reactor with a mixing speed of 400 rpm for 2 h at 50 °C. The molar ratio of oil to methanol was 1:10. Finally, the mixture was left overnight to settle form­ing two layers, namely: biodiesel phase (upper layer) and the glycerin-rich phase (Figure 3).

Property

EN 14214

ASTM D 6751

Test method

Limits

Test method

Limits

Ester content

EN 14103

96.5% (mol mol-!) min

_

Linolenic acid content

EN 14103

12.0% (mol mol-1] max

Content of FAMEJ with 2:4 double bonds

1.0% (md mol-1) max

MAG1’ content

EN 14105

0.80% (md mol-1] max

DAG1 content

EN 14105

0,20% (md mol-1) max

TAG*1 content

EN 14105

0.20% (md mol — ‘) max

Free glycerine

EN 14105

0.02% (md mol-‘] max

ASTM D 6584

0.020% (w/w) max

Total glycerine

EN 14105

0.25% (md mol-‘) max

ASTM D 6584

0.240% (w/w) max

Water and sediment or water content

EN ISO 12937

500 mg kg-1 max

ASTM D 2709

0.050% (v/v) max

Methanol content

EN 14110

0.20% (md mol-1] max

(Na+K) content

EN 14108

5.0 mg kg-‘max

UOP391

5.0 mg kg-‘max

(Ca + Mg) content

prEN 14538

5.0 mg kg-1 max

P content

EN 14107

10.0 mg kg-1 max

ASTM D 4951

0.001% (w/w) max

Oxidative stability (110 °С)

EN 14112

6 hmin

Density (15 °С)

EN ISO 3675

860-900 kgm-3

Kinematic viscosity or viscosity (40 °С)

EN ISO 3104

3.5-5.0 mm2!-1

ASTM D 445

1.9-6.0 mm! r1

Flash point

EN ISO 3679

120 °С min

ASTM D 93

130 °С min

Cloud point

ASTM D 2500

Not specified

Sulfur content

EN ISO 20864

10.0mg kg-‘ max

ASTM D 5453

0.05% (w/w) max

Carbon residue

EN ISO 10370

0,30% (md mol-‘] max

ASTM D 4530

0.050% (w/w) max

Cetane number

EN ISO 5165

51 min

ASTM D 613

47 min

Sulphated ash

ISO 3967

0.02% (md mol-!) max

ASTM D 874

0.020% (w/w) max

Total contamination

EN 12662

24 mg kg-1 max

Copper strip corrosion (3 h, 50 °С)

EN ISO 2160

1 (degree of corrosion

ASTM D 130

No. 3 max

Acid number or acid value

EN 14104

0.50 mg KOH g-1 max

ASTM D 664

0.50 mg KOH g — ‘max

Iodine value

EN 14111

120 g 12-100 g-1 max

Distillation temperature (90% recovered]

"

ASTM D 1160

360 °С max

‘ FAME — fatty acid methyl esters. ’ MAG = monoacylglycerines.

DAG = diacylglycerines.

1 TAG = triacylglycerine.

Table 2. Biodiesel specifications according to EN 14214, and ASTM D6751 standards.

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