ALTERNATE FEEDSTOCKS FOR ALCOHOL PRODUCTION ACHIEVING EBP SUCCESS S. Kumar, S. Paroha & N. Mohan NATIONAL SUGAR INSTITUTE KANPUR National Sugar Institute, Kanpur 16-OCT-15 1
INTRODUCTION The present human activity is mostly based on fossil fuels i.e. crude oil, coal and natural gas. India, a fast growing economy is facing the challenge of a rapidly increasing demand of energy. It ranks sixth in the world in terms of energy demands which is likely to grow to achieve targeted GDP.
India s requirement of petro products is around 130 MMT against an annual global requirement of 18000 MMT i.e. barely 0.7% of world. The domestic production of crude and natural gas is only around 35 MMT. The demand of crude oil is to increase substantially to manage transportation and other energy needs. The huge gap between demand and supply is met by import.
Our crude import bills have increased 13 times in last two decades and it is expected that by 2020 it will increase 50 times. Thus to avoid huge pilferage of foreign currency for crude imports, there is need to produce bio fuels i.e. fuels derived from renewable substrates (agricultural products) to meet our energy demands. Out of these, ethanol is most important which is produced by fermentation.
World Ethanol Production I. Ethanol is the chemical which is produced in largest quantities by fermentation and distillation industries. II. The global production of ethanol is in the range of about 110 billion liters III. Out ofthis, fuel ethanol accounts for more than 80% (USA tops the list) IV. India s production is only 3% of world production which is even less than 50% of China s production. V. Feedstock wise, majority of alcohol is produced from coarse grains (50%), followed by cane juice (32 %) and molasses (18%).
Indian Demand & Production of Alcohol I. The no. of distilleries in India are around 370. II. The total installed capacity of distilleries is about 6.4 billion (6400 million liters). The molasses accounts for 4400 million and grain 2000 million liters. III. Against installed capacity of 6400 million liters per annum, annual production is around 3900 million liters, of which molasses accounts for around 2400 million liters (it was 1800 Million litres in 1985 itself) and grains 1500 million liters.
The annual requirement of alcohol, at present, is approximately 2300 million liters for potable sector in which grain spirit contributes by around 1500 million liters. Thus, alcohol requirement for potable sector through molasses route is approx. 800 million liters/annum. Similarly, for industrial/chemical Industry purposes, the molasses based alcohol is expected to be approx. 800 million liters/annum. The installed capacity of ethanol in India is approx. 2200 million litres Requirement of ethanol for 5% EBP is 1150 million litres and for 10% EBP it shall be around 2300 million litres.
Biochemistry of Alcohol Production Alcohol is produced by fermentation (with yeast) of fermentable sugars by the following formula: Glucose Alcohol + Carbon dioxide C 6 H 12 O 6 2C 2 H 5 OH + 2 CO 2 180 92 88 180 g glucose gives 92 g alcohol 1 g shall produce 92/180 = 0.511 g (Theoretical) 1 g thus shall produce 0.511/0.793 = 0.644 ml alcohol
It can be seen that fermentation takes place from glucose and all the carbohydrates (which are polymers of glucose) are essentially needed to be converted to glucose before fermentation. RAW MATERIALS FOR FERMENTATIVE PRODUCTION OF ALCOHOL: A large no. of raw materials can be utilized for the fermentative production of ethanol. These are classified in three categories viz. saccharine, starchy and cellulosic.
Saccharine Materials 1. Saccharine materials include cane juice, beet juice, cane molasses, beet molasses, grapes etc. 2. Out of these, molasses is the cheapest and main raw material utilized for the fermentative production of alcohol. 3. On weight basis, one ton of molasses can produce alcohol to an extent of 230-240 liters depending on the TRS content.
4. Sugarcane juice is also a potent raw material which can be used for the production of alcohol with yield of 70-80 l/ton. 5. In many countries, sugarcane juice is fermented to produce alcohol either for fuel sector or for the manufacture of rum. 6. Due to high cost of sugarcane, production of alcohol from sugarcane juice may not be viable in India.
STARCHY MATERIALS The starchy materials are mainly represented by corn, wheat, rice, barely etc. In U.S., the majority of alcohol is produced by corn, while European countries use barley for alcohol production. Ethanol yield from grains (on dry weight basis) ranges from 370-450 liters/tons. However, due to high cost and shortage of food grains in India, its abundant use may create a debate on Fuel vs Food.
Ligno-cellulosic Materials These are available in plenty and are represented by wheat and rice stalk, grasses, wood material, plant waste material and bagasse. These also needed to be converted to fermentable sugars after hydrolysis ofde-lignified bagasse. However, the conversion ofcellulose to fermentable sugars is costly. Ethanol yields from bagasse - a lignocellulosic material may be up to 220 litres per ton.
ALTERNATE RAW MATERIALS Though majority of alcohol in world is produced from saccharine and starchy raw materials including those which are also consumed as food. However, the production of alcohol from these (other than molasses) may not be desirable in our country.
The following are some alternate feed stocks which can be utilized for the fermentative production of ethanol. These are categorized as alternate raw materials since these are normally not utilized for fermentative production of alcohol but can be used in place of conventional raw materials. These were tried on experimental basis at our Institute laboratory for alcohol production.
The sweet sorghum which is mainly the crop of Southern India has been grown at NSI farm and the expressed juice was subjected to fermentative production of alcohol and a yield of 45 l/ton was obtained Similarly, rice bran powder a by product of rice bran oil industry was also utilized for alcohol production and an yield of 235 l/ton was obtained. In the present context, the production of alcohol from cassava, sugar beet and B-Heavy molasses has been discussed.
CASSAVA It is the third largest source of carbohydrates with annual world production of around 210 million tons. In India, the yields of cassava are highest i.e. 33.33 tons/hectare (compared to Thailand 21.6, Brazil 13.84 and world average 12.12) with annual production of around 7235 thousand tons and Tamil Nadu only accounts for more than 50%. The fresh roots have a starch content of around 30% and as such or dried cassava chips / powder can be utilized for the fermentative production ofalcohol.
Cassava roots: Cassava chips Cassava powder National Sugar Institute, Kanpur
Chemical Composition of Cassava Powder Sl. No Particulars Values 1. Starch content 74.06% 2. Moisture 12% 3. Protein 4% 4. Fat 0.5% 5. Ash content 2%
Considering the yield of cassava and its potential to be grown elsewhere due to its capability to tolerate extreme stressed conditions and less requirement of water, it is widely being utilized for fermentative production of ethanol in Thailand. The fresh roots have a starch content of around 30% and as such or dried cassava chips / powder can be utilized for the fermentative production of alcohol. We at NSI Kanpur have worked on the production of ethanol from cassava powder (provided by Central Tuber Research Institute, Thiruvanthapuram (Tamil Nadu)
For this, the cassava flour was gelatinized, liquefied and saccharified as per standard procedure usually employed for starchy raw materials. The saccharified material was subjected to fermentation by S. cerevisiae. It was seen that a fermentation efficiency value of around 90.5% was obtained with alcohol yield of 354 liters / ton of cassava on dry weight basis (corresponding to 372.5BL / ton).
Fermentative production of alcohol from cassava powder S.No. Particulars Values 1. Quantity of cassava flour 100 g 2. Starch content 65.6% 3. Starch content (dry weightt basis) 74.6% 4. Final volume of wort after saccharification 650 ml 5. Total sugars in wort after saccharification 56% 6. Starch to sugar conversion percent 85.4% 7. Total sugars in wort (g/100 ml) 8.61% 8. Unfermentable sugars in wort (g/100 ml) 0.2% 9. Fermentable sugars in wort (g/100 ml) 8.41% 10. Theoretical Ethanol percent (v/v) 5.41% 11. Actual Ethanol percent (v/v) 4.9 % 12. Fermentation efficiency 90.5% 13. Ethanol yield in AL (l/ton) 354 14. Ethanol yield in BL (l/ton) 372
SUGAR BEET Sugar beet is one of the most efficient convertors of solar energy into stored energy (carbohydrate and sugar). It is a 6 7 month crop and yields nearly as much sugar as a 12 month sugar crop. It is mainly the crop of tropical region but it can also be grown in subtropical regions. The crop (LS-6 variety) was grown at this Institute which was sown in October and harvested in April (seed was provided by Indian Institute of Sugar cane Research Lucknow) and an yield of 85 tons / hectare was obtained.
National Sugar Institute, Kanpur
For fermentative production of alcohol, the beet roots were grated and hot water extraction of the juice was carried out, washed a few times with hot water and the juice was analyzed for various chemical constituents including TRS content. The juice was fortified with nutrients, ph adjusted to 4.5 and then sterilized at 15 p.s.i.g. for 15 minutes. After cooling, it was pitched with yeast and fermentation was carried out. The results obtained showed that the ethanol yield of around 100 liters/ton (corresponding to 107 BL)was obtained with fermentation efficiency value of over 85%.
Chemical composition of Sugar beet juice Sl. No Particulars Values 1. Brix (Total Dissolved Solids) 19.8 2. Pol (Sucrose) 16.5% 3. Purity 70 4. Reducing Sugars 2.2% 5. Total Reducing Sugars 19% 6. ph 5.6
Fermentative production of alcohol from sugar beet juice S. No. Particulars Values 1. Quantity of Sugar beet 3 Kg 2. Final Volume of Juice 5 litres 3. TRS Content of juice (g/100 ml) 11.4% 4. Residual Sugars (g/100 ml) 0.4% 9. Fermentable sugars in wort (g/100 ml) 11.00% 10. Theoretical Ethanol percent (v/v) 7.08% 11. Actual Ethanol percent (v/v) 6.1% 12. Fermentation efficiency 86.16% 13. Ethanol yield in AL (l/ton) 101.6 14. Ethanol yield in BL (l/ton) 107.5
ALCOHOL FROM B HEAVY MOLASSES B Heavy molasses is generated by two massecuite boiling scheme comprising of A and B massecuites. The diversion of this molasses for fermentative production of ethanol can help boost EBP success. We have collected the samples of B Heavy and final molasses from 17 sugar factories including 3 from Tamil Nadu, 6 from Maharashtra and 8 from Uttar Pradesh. TRS, UFS, FS and VFA content of molasses from these factories is given in Table.
It is seen that TRS Content of B Heavy molasses in samples received from factories of Tamil Nadu ranged from 52.4-59.58, UFS in the range of 2.3 2.89% and VFA from 2133 2426 mg/l. With final molasses, TRS ranged from 42.78 44.53%, UFS from 4.88 5.05% and VFA from 3454 3957 mg/l.
The TRS of B Heavy molasses collected from factories of Maharashtra ranged from 52 58% and UFS from 2.12 2.80%. VFA ranged from 2051 2528 mg/l. The TRS of final molasses ranged from 42.70 49.64%, UFS from 4.75% - 5.97% and VFA from 3436 3841 mg/l. In the samples of B Heavy molasses from factories of Uttar Pradesh, the TRS content of 52.23 55%, UFS from 2.04 2.78% and VFA content from 2096 2648 mg/l. TRS content in final molasses usually ranged from 40 46%, UFS from 4.90 5.51% and VFA content from 3608 3950 mg/l.
It is seen from the above data that the TRS content in B heavy molasses ranged from 52 58% in the states of Tamil Nadu and Maharashtra while it was little bit on the lower side (52 55.4%) in the state of Uttar Pradesh. The TRS content of final molasses was nearly same in all the states barring a few exceptions. UFS content in B- heavy molasses was below 3% while in final molasses it varied up to a maximum of around 5.5%. The average TRS content of B- heavy molasses in the states of Tamil Nadu, Maharashtra and Uttar Pradesh was 56, 54 and 53% respectively while for final molasses. the values were 42, 47 and 44%.
The alcohol production figures at these TRS content have been depicted in Table below. It is seen that alcohol production from B- Heavy molasses was little less than 300 l/ton while with final molasses it was around 225 litres. It may be concluded that TRS contents of B Heavy molasses did exhibited variations in the samples from different states, it was around 55% and in none of the samples, it was more than 60% as was considered in the beginning and yield of over 330 l/ton was estimated. The data show that ethanol yield from B Heavy molasses shall remain around 300 l/ton (it will be function of TRS), however, the capacity utilization may increase slightly.
TRS, UFS, FS and VFA content molasses samples received from factories of Tamil Nadu S. No Factory Sample TRS g% UFS g% FS g% VFA mg/l 1. Udapalli B/H 42.40 2.89 19.51 2133 F/M 40.56 5.05 35.51 3450 2. Tirmandalkundi B/H 52.4 2.76 55.10 2314 F/M 42.30 4.88 37.82 3957 3. Kaungulam B/H 59.58 2.31 57.27 2426 F/M 44.53 4.91 39.62 3693
S. No TRS, UFS, FS and VFA content molasses samples received from factories of Maharastra Factory Sample TRS g% UFS g% FS g% VFA mg/l 1. Hupari B/H 55.60 2.44 53.16 2528 F/M 33.33 5.68 27.65 3773 2. Kagal B/H 53.01 2.53 50.48 2119 F/M 42.78 4.75 38.03 3711 3. Yeshwantpur B/H 44.60 2.13 42.47 2386 F/M 43.04 5.32 37.72 3436 4. Shignapur B/H 57.62 2.86 54.76 2278 F/M 51.80 4.74 47.06 3715 5. Shiroli B/H 58.23 2.12 56.11 2051 F/M 49.22 4.83 43.39 3485 6. Jalna B/H 52.46 2.80 49.66 2310 F/M 49.64 5.97 43.67 3841
TRS, UFS, FS and VFA content molasses samples from Uttar Pradesh S. No Factory Sample TRS g% UFS g% FS g% VFA 1. Chilwaria B/H 49.00 2.04 46.96 2417 F/M 40.20 5.40 34.80 3608 2. Nanpara B/H 55.00 2.34 52.66 2284 F/M 40.00 5.09 34.91 3618 3 Akbarpur B/H 53.00 2.58 50.42 2248 F/M 36.20 5.89 30.31 3576 4. Ajabapur B/H 57.00 2.77 54.23 2648 F/M 44.00 4.96 39.04 3520 5. Nigohi B/H 55.00 2.41 52.59 2595 F/M 45.00 5.27 39.73 3739 6. Libberheri B/H 53.55 2.78 50.77 2372 F/M 46.37 4.90 41.47 3846 7. Deoband B/H 52.23 2.71 49.52 2096 F/M 46.00 4.94 41.06 3950 8. Jawaharpur B/H 54.71 2.29 52.42 2167 F/M 48.95 5.51 43.44 3651
Fermentative production of Alcohol from B- Heavy and final molasses Sl No. Sample State Av TRS g% UFS g% FS g% Ethanol yield l/ton 1. B/H Tamil Nadu 56 2.5 53.5 298.0 F/M 42 4.8 37.2 200.5 2. B/H Maharashtra 54 2.5 51.5 287.0 F/M 47 4.8 42.2 227.5 3. B/H Uttar Pradesh 53 2.5 51.5 287.4 F/M 44 5.0 39.0 210.0
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