Working of Bio-Diesel production plant

These are the steps involved in production of Biodiesel from Jatropha.

 

1. In the first step Jatropha seeds are treated with hot steam at around 60 to 70 °C which helps in better oil extraction. Oil from seeds is extracted using a mechanical extraction process (crushing). Jatropha seeds contain 35 to 40 % oil by mass and by crushing 28 to 30 % oil is recovered. Which is then allowed to settle in a sediment tank. The By-Product of this step is Jatropha cake which contains 5-7 % oil. This By-Product can be used as fertilizer or it can be used for burning.
2. In the next step extracted oil is filtered through a filter-press.
3. In the next step filtered oil is treated with 5 N solution of NaOH to remove free fatty acid (600 gm of NaOH in 3 lit of water for 125 kg of oil). The neutralized reaction takes 15 minutes with proper stirring. The result of neutralized reaction is soap formation.
4. In the next step oil is separated from soap by sucking the oil through a vacuum pump.
5. In the next step methoxide is produced using methanol and KOH for transesterification process. Around 50 kg of methoxide for 265 kg of oil.
6. The next step is transesterification where methoxide is mixed with oil to produced methyl ester (Biodiesel) and glycerol. The reaction takes around 2 hours to complete. Agitation is provided throughout the reaction. A successful reaction produces two liquid phases: ester and crude glycerol. Crude glycerol, the heavier liquid will collect at the bottom after several hours of settling. After the transesterification reaction, one must wait for the glycerol to settle to the bottom of the container. This happens because Glycerol is heavier then biodiesel. The settling will begin immediately, but the mixture should be left a minimum of eight hour (preferably 12) to make sure all of the Glycerol has settled out. The Glycerol volume should be approximately 20% of the original oil volume.

7. In the next step methyl ester is treated with water for 2 hours. The amount of wash water should equal the amount of oil, and can be drained throughout the washing process.  After this water is separated by gravity separation. After the water is drained, the air washing process can start. At this point, the biodiesel is usually a pale yellow color. Air should be bubbled through the biodiesel mixture for approximately 8 hours. The bubbling should be just enough to agitate the biodiesel surface. A final drain of accumulated contaminants is done immediately after the air bubble wash is finished. The fuel is now ready for use.
8. The By-product of step 6 is used to get crude glycerin. Methanol is separated from glycerol by vacuum distillation process. After methanol removal glycerol is neutralized with H₂SO₄. This neutralized reaction results in two products first is water which contains glycerin and K₂SO₄. And second product is acidic oil (FFA).
9. The mixture of water, glycerin and K₂SO₄ is then evaporated to get K₂SO₄ crystals which can be used as fertilizer for soils low in potassium. At the end of this process we get refined glycerin (65%) which goes through a process of distillation to get distilled glycerin (85%).

 

 

Plant capacity: One M. T. of Jatropha seeds yields 275 lit of Biodiesel, 40-45 kg of soap, 7-9 kg of K₂SO_4, 20 kg of glycerin and about 14 kg of Methanol is recovered.

The inputs are 1.5 kg of NaOH, 50 Kg of Methanol and about 2.5 kg of KOH.

Biodiesel Basics

 

What is Biodiesel?

 

A fuel comprised of mono-alkyl esters of long chain fatty acids (known as Fatty Acid

Methyl Esters or FAME) derived from vegetable oils or animal fats, officially designated as B100 or 100% Biodiesel in compliance with ASTM D6751 (USA) or EN 14214 (Europe) industry specifications. The standard manufacture process to make biodiesel is called transesterification. Biodiesel is a renewable fuel for diesel engines. Biodiesel, defined by ASTM International (D6751), consists of longchain fatty acid alkyl esters and is made from renewable vegetable oils, recycled cooking oils, or animal fats. Biodiesel (fatty acid alkyl esters) is a cleaner-burning diesel replacement fuel made from natural, renewable sources such as new and used vegetable oils and animal fats. Just like petroleum, biodiesel operates in compression-ignition engines. Blends of up to 20% biodiesel can be used in nearly all diesel equipment. Low levels generally do not require any engine modifications.

 

 

How Is Biodiesel Made?

 

Biodiesel can be produced by several processes. Vegetable oils or fats can be converted to fatty acids, which in turn are converted to esters. Oils or fats can also be converted to methyl or ethyl esters directly, using an acid or base to accelerate (catalyze) the transesterification reaction. Base catalyzation is preferred, because the reaction is quick and thorough. It also occurs at lower temperature and pressure than other processes, resulting in lower capital and operating costs for the biodiesel plant. The most common method of producing biodiesel is to react animal fat or vegetable oil with methanol in the presence of sodium hydroxide (a base, known as lye or caustic soda).The process of making biodiesel starts with the addition of vegetable oil, catalyst, and methanol into a reactor. The oil and methanol are converted to biodiesel and glycerin through a process called transesterification. The biodiesel and glycerin are separated and further processed so that the result is a biodiesel product.

 

Why Use Biodiesel?

 

·         Renewable energy alternative, biodegradable & nontoxic.

 

·         Using biodiesel decreases this dependency on foreign oil.

 

·         B2 level provides significant lubricity improvement.

 

·         Biodiesel improves air quality, which makes the environment healthier for our communities.

 

·         Biodiesel contains more energy than what was used to produce it. For every one unit of energy that goes into making a gallon of biodiesel, 3.24 units of energy are stored for future use. For every one unit of energy that is used to make a gallon of petroleum diesel, only 0.83 units of energy (0.17 less than the amount of energy used to produce the fuel) are stored for future use.

 

·         When using pure biodiesel, the exhaust emissions of carbon monoxide (a poisonous gas and a factor in local smog formation) are 50 percent lower than when using petroleum diesel. The exhaust emissions of hydrocarbons, which also contribute to smog formation, are 95 percent lower.

 

·         The exhaust emissions of sulfur oxides (Sox) and sulfates, which are major components of acid rain, from biodiesel are almost completely eliminated.

 

·         Biodiesel has a higher flashpoint, so it safer - it won’t catch fire as easily.

 

·         Readily mixes with petroleum diesel fuel in any ratio