THE PATENTS ACT, 1970

(39 of 1970)

The Patents [Amendments] Rules, 2006

GRANTED PATENT 283047

COMPLETE SPECIFICATION

(See section 10 and rule 13)

BIO-DIESEL FROM FATTY ACIDS OF MUSTARD OIL

Puri Oil Mills Ltd.

302, Jyoti Shikhar Building, District Center, Janak Puri,

New Delhi 110058

The following specification particularly describes and ascertains the nature of this invention and the

manner in which is to be performed.

Bio-Diesel from Fatty Acids of Mustard Oil

1. Technical Field of the Invention:

The present invention relates to novel process for developing biodiesel from fatty acids

derived from residual oil extracted from mustard meal. More particularly the invention

relates to the utilization of fatty acids from fat splitting and fractionation plant source after

separating the erucic acids and utilizing the remaining lower fatty-acids for conversion to

bio-diesel through trans - esterification.

The invention also provides for a system of plant lay-out for carrying out the above unit

operations of the developed process.

2. Background of the Invention and Prior Art

Biodiesel produced from vegetable oils as an alternative fuel has gained popularity in recent

years for its environment-friendly characteristics of low emission rates of CO, HC and CO₂. A

variety of plant sources, such as soybean, rapeseed, canola, neem, jatropha as well as

animal fat are being widely explored in many parts of the world for their oil content as

feedstock for biodiesel. Rudolf Diesel, the inventor of first compression ignition engine for

which he was granted a patent in 1893, was himself a strong proponent of vegetable oil as a

potential source of fuel in the diesel engine. However, due to cheap and abundant

availability of petroleum based diesel, the use of vegetable oil as a fuel in the diesel engine

was pushed aside for more than hundred years.

The first public demonstration of vegetable oil based diesel fuel was sponsored by the

French government at a World Fair in 1900 using peanut oil. However, as the petroleum

based diesel engines evolved with newer and more efficient injection mechanisms, these

engine designs could not run on traditional vegetable oils primarily due to the much higher

viscosity of vegetable oils compared to petroleum diesel fuel. It was evident that a way was

needed to lower the viscosity of vegetable oils to make them suitable for use in modern

diesel engines.

It was in

1937 that a Belgian inventor proposed using trans-esterification to convert

vegetable oils into fatty acid methy esters

(FAME) and use them as a diesel fuel

replacement. Thus, the trans-esterification reaction is the basis for the production of

modern biodiesel.

The production of biodiesel is generally carried out by base catalysis of vegetable oils. The

first step of base catalyzed production of biodiesel process is mixing of alcohol and catalyst

using a standard agitator or mixer. The catalyst is typically sodium hydroxide (caustic soda)

or potassium hydroxide (potash). The alcohol/catalyst mix is then charged into a closed

reaction vessel and the oil or fat is added. The system from here on is totally closed to the

atmosphere to prevent the loss of alcohol. The reaction mixture is kept just above the

boiling point of the alcohol (around 70 °C) to speed up the reaction. Recommended reaction

time varies from 1 to 8 hours, and some systems recommend the reaction take place at

room temperature. Excess alcohol is normally used to ensure total conversion of the fat or

oil to its esters.

Precaution is required to monitor the amount of water and free fatty acids in the incoming

oil or fat. If the free fatty acid level or water level is too high it may cause problems with

soap formation and the separation of the glycerin byproduct downstream. Once the

reaction is complete, two major products exist: glycerin and biodiesel. Each has a

substantial amount of the excess methanol that was used in the reaction. The reacted

mixture is sometimes neutralized at this step. The glycerin phase is separated from

biodiesel phase by gravity and natural sedimentation or sometimes by centrifugation. The

excess alcohol is then removed with a flash evaporation process or by distillation.

Alternatively, the alcohol is removed and the mixture neutralized before the separation.

The recovered alcohol is re-used in the process.

The trans-esterification process as described above in nut-shell is the main process used for

biodiesel production since mid 19th century, though there are quite a few other processes

such as pyrolysis, micro-emulsion technique, direct blending etc. also known. In this trans-

esterification process, the triglyceride ester is reacted with alcohol (usually methanol) to

produce another ester (methyl ester) and alcohol (glycerol).

There are several patents in the prior art relating to the production of biodiesel from fatty

acids of vegetable oils. i.e., US patents 5482633, 5514820, 5536856, 5945529 and 6015440.

The processes described therein differ from each other in terms of source of vegetable oil,

choice of catalyst, reaction parameters, range of bye-products etc. The industries are taking

interest in commercializing some of these technologies on account of the techno-economic

viability of the production process and net operating returns of a representative plant which

co-produces a mix of bye-products such as glycerin, fatty acids, and filter-cake improving

the profit margins.

The present invention discloses a trans-esterification process of some of the fatty-acids

derived from mustard oil to produce fatty acids methyl ester (FAME) with very high

conversion rate for biodiesel and co-production of valued added erucic acids along with

conventional glycerol. The process of producing the end-product, biodiesel with a bye

product, erucic acid is ‘novel’ and ‘inventive’.

In India, Ministry of Non-Renewable Energy (MNRE), has been promoting the use of non-

edible oils for biodiesel production. Among the edible oils, mustard is important oil in India

which is widely used in most Indian house-holds and restaurants for cooking.

India produces more about 65 to 70 lakh tons of mustard annually which constitutes about

11% of the global production; nearly all of the oil seed with ~40% of oil content is processed

of which about 80% production is accounted for in the small scale sector. The overall yield

of the refined oil is generally around 30%; thus, approximately 20 lakh tons of refined oil is

available for domestic edible consumption. The remaining 10% of oil remains adhered to

the mustard cake which is extracted by alternate means but is usually unfit for human

consumption.

This invention is targeted to make good use of this resource which on country basis is

around 7 lakh tons currently and can easily be diverted to biodiesel production. The use of

this resource is likely to strengthen the country’s rural economy also with wide-scale

adoption of this technology like palm-oil is a major source of bio-diesel in Malaysia.

3. Object of Invention

The primary objective of the this invention is to develop a commercially viable process

technology including catalytic conversion method and plant lay-out equipment for the

production of bio-diesel (i.e., fatty acids methyl / ethyl ester) from erucic acid free fatty

acids derived from Indian mustard oil, more specifically from waste mustard oil.

Yet another objective of the present invention is to provide co-production of pure erucic

acid as a value added bye product of biodiesel production from mustard fatty acids.

4. Summary of Invention

The invention provides a method and system to obtain the biodiesel conforming to ASTM

and BIS standards with more than 98% conversion from fatty acids derived from Indian

mustard oil.

The main starting material of this invention is waste mustard oil or residual oil obtained

from mustard cake through solvent extraction. This mustard oil is split into glycerin and

fatty acids. The fatty acids are then fractionated into two major fractions as erucic acids

(C22: 1) and mixed fatty acids. The mixed fatty acids fraction which is essentially free from

erucic acids (C22:1) is converted to methyl ester through trans-esterification resulting into

Biodiesel of ASTM/BIS standard which can be used as a fuel for automotive engines direct or

as a blend with petroleum based diesel. The process disclosed herein provides Biodiesl of

very high quality along with two value added bye products, viz., erucic acid and glycerin. All

the resultant products of this invention after due purification are industrially useful and

together make the invention commercially viable.

5. Brief Description of the Accompanying Drawings

Figure 1 describes the steps of the process for preparing the starting material of this

invention viz., rresidue mustard oil.

Figure 2 shows a process flow diagram for preparing biodiesel along with two bye products,

viz., erucic acids and glycerol starting from the residue mustard oil.

Figure 3 shows the process flow diagram of the trans-esterification process of this invention

in one embodiment

6. Detailed Description of the Invention

Problem Identification & Technological Solution

In view of widespread use of variety of vegetable oil for biodiesel production, it was

obvious to explore the use of mustard oil for this purpose which has not been tried hitherto

and is plentiful in India. The developer of this technology and applicant of this invention is

research driven company and is one of the major producers and supplier of mustard oil

throughout India.

As already stated before, most vegetable oils exist in high viscosity range so that these

cannot be used directly in conventional engines. Thus, these are necessarily converted to

methyl esters by trans-esterification process resulting into a product of lower viscosity

suitable for most internal combustion engines with no or minor modification. Unlike most

other vegetable oils, however, mustard oil contains more long-chain fatty acids and

therefore biodiesel derived from it turns out to be slightly more viscous (thicker) and has

higher distillation temperature than the ASTM D6751 specification allows. This presents a

major technological challenge in the use of mustard oil for biodiesel production.

In order to find a workable solution to the problem, the composition of various fatty acids

in mustard oil was looked at in comparison to other vegetable oils. It was found, that

mustard oil contains ~22-50 % Erucic acid, a (C22:1) fraction and ~5-13 % of Ecosenic acid, a

(C20:1) fraction, which are normally not present in other commonly available vegetable oils

used in biodiesel production. The remaining fatty acids, namely linolenic acid (C18:3) (6-

18%), linoleic acid (18:2) (10-24%), oleic acid (C18:1) (8 - 23%), stearic acid (C18:0) (0.5-2%)

and palmitic acid (C16:0) (0.5-4.5 %) are present in mustard oil as in most other vegetable

oils, such as sunflower, soybean, palm etc. albeit in varying quantities.

Novelty & Inventiveness

In view of the above, separation of some of these longer chain fatty acids, particularly

erucic acid through fractionation before trans-esterification of the remainder of fatty-acids

mixture was considered as a possible solution. This approach proved fortuitous and

worked well. The process as disclosed is both ‘novel’ as well as ‘inventive’ as i) biodiesel

from mustard oil and ii) erucic acid co-production with biodiesel are not hitherto reported

in scientific and patent literature.

While many facets of the technology disclosed herein are in the realm of prior art, such as

oil refinement, fat splitting and fractionation, the process of trans-esterification as

reported herein that provides enhanced surface-area and possible innovations with regard

to implementing the technology by way of process engineering, related to choice of

catalyst, equipment and optimization of reaction conditions are quite unique. All inventive

features of the developed technology will be evident from the description of complete

specification that follows here with the help of accompanying drawings.

Other objects and aspects of the invention will become apparent from the following

description and the embodiments with reference to the accompanying drawings, which is

set forth hereinafter. The embodiments of the present invention can be modified variously.

Thus, the scope of the present invention should be construed not limited to the description

and embodiments provided herein. The embodiments are provided to better explain the

present invention to those of ordinary skill in the art.

Reference Numerals in the drawings (Figure 3)

5 = Alcohol (Methyl / Ethyl alcohol) Tank

10 = Free Fatty Acid Tank

15 = Catalyst inlet

20 = Vessel for mixing and emulsification

25 = Steam inlet

30 = Pressure Reactor with steam inlet

40 = Steam / water condenser

45 = Outlet for condensed water

50 = Settling tank

60 = Cross flow or multi-phase filter

70 = Collection vessel for crude fatty acid methyl ester (Biodiesel)

Process Description

The process starts from residue mustard oil which is obtained as shown in the Figure 1 .

The further process steps starting from this oil are shown in a flow diagram in the Figure 2.

Fat Splitting: The very first step in Figure 2 is ‘fat-splitting’ operation which essentially is a

hydrolysis process. Mustard oil is pumped from the storage tank to the splitting plant via a

steam based pre-heater. The heated oil enters the pressurized splitting column from the

bottom of the splitting column. Demineralized water is fed to the top of the column with a

high pressure pump resulting in a countercurrent flow. High pressure steam is injected into

the column to provide the necessary heat. A pressure of about 55 bar is maintained along

with a temperature of above 250°C. The process is continuous and glycerin water is

continuously discharged from the bottom while split fatty acids are discharged from the

top of the splitting column. The fatty acid mixture is cooled and dried in a flash evaporator.

Similarly, glycerin water goes to a flash-evaporator and the condensate collected and

reused as process water.

Fatty Acid Fractionation

The erucic acid component in the fatty acids mixture is separated from the remaining fatty

acids in a custom built fractionating column. The fractional distillation returns the erucic

acid of 90% or more of purity.

Trans-Esterification of Fatty Acid Mixture

The main process steps of trans-esterification along with equipment lay-out are depicted in

Figure 3. In the disclosed process the free fatty acids is remaining after separating the

erucic acid component are converted by acid esterification into fatty acid methyl or ethyl

esters in presence of catalyst sulphuric acid at 180 - 280 °C under pressure of 400 - 1 OOO

kPa. The conversion rate of this process is 99%. The equipments used are acid resistant

containers such as stainless steel containers.

Example

The conversion of fatty acids to biodiesel was carried out in an experimental set-up as

shown in Figure 3 using the following process:

Free fatty acids (10) from fat splitting plant were taken and analyzed for their acid value,

triglyceride content etc. The fatty acids from (10) were then mixed with alcohol (5) such as

methanol or ethanol from 5-35% on free fatty acid weight basis and a proper stirring or

blending was carried out in (20) at 100 - 300 rpm, preferably at 200 - 250 rpm, for proper

mixing of the alcohol (methanol) and fatty acids.

Acid catalyst such as sulphuric acid (15) is added at the rate of 0.1-2% and further stirring is

done. The whole mixture is then loaded in a pressure reactor (30), which is heated with live

steam (25), the pressure of the chamber being 400 - 1OOO kPa, preferably 800 - 1000 kPa.

The reaction was continued for a minimum of 30 min to up to 3 hours. The output of this

process is fatty acid ester (methyl or ethyl), sulphuric acid, water and traces of some

triglyceride.

In this process, the water (45) is removed as steam condenses in a condenser (40) attached

to the main pressure reactor (30). The water (45) is continuously removed. The water

vapour out-flow has been observed to take away a mist of acid catalyst with it. Thus,

additional quantities of acid catalyst at the rate of 0.1 - 1% is required to be fed during the

reaction. The methyl or ethyl ester of fatty acids mixture obtained on completion of the

reaction is transferred to a settling tank (50).

To work out the reaction product of methyl ester of the fatty acids settled in (50), water

wash was employed to remove acidic impurities followed by filtration through cross-flow

filtration (60). This important process step allows a separation of the individual phases of

the mixture followed by water washing and drying of the final product of biodiesel which

conforms to ASTM and BIS standards.

Possible Embodiments of Equipment and Plant Lay-out

There are many possible embodiments of equipment layout to perform this invention and

obtain desired results, some of which are described below.

1. In this embodiment of the invention, the separation of the emulsion phases is

performed by exploiting the surface forces in a well-designed cross-flow filter. In

another embodiment of the invention, the multiple phases of the emulsion were

separated by multiphase filtration. Thereby, the water was separated in the first step,

and the triglycerides were separated as residue in the second step. In a third step,

methanol is separated from the fatty acid methyl ester.

2. In yet another embodiment of the invention, distillation can be carried out directly on

the reaction product of (50) after chemical balance state is reached, possibly after

separation of the phases of the mixture employing vacuum distillation at a much

reduced temperature.

3. In another embodiment, multiphase distillation on the the reaction product from

pressurized reactor (30) employing evaporation, in particular down-flow evaporation.

4. The aim of the invention is realized independently by judicious choice of equipment for

implementation of the process. The equipment as required to perform the invention

includes the following -

a. at least one container for the fatty acids, and

b. at least one source tank each for the catalyst sulphuric acid solution, and the

alcohol,

c. at least one mixing vessel for compounding,

d. at least one pressurized reaction vessel connected with a boiler for live steam.

e. a unit for separating the phases of the emulsion downstream from the reaction

section.

f. a high pressure pump for injecting the emulsified feed with a turbulence into

the pressurized reactor

5. In yet another embodiment of equipment required for the invention, following may

include -

a. a dynamic separator for creating and managing liquid-liquid emulsions.

b. a cross-flow or multi-phase filtration unit or alternatively a surface filter

designed as a plate filter with cotton cloth appropriate pore size.

c. a distillation unit comprising of an evaporator and a condenser in the

downstream section of the main reactor, alternatively,

d. a down-flow evaporator or a vacuum evaporator or a thin-layer evaporator.

While the present invention has been described with respect to certain preferred

embodiments, it will be apparent to those skilled in the art that various changes and

modifications may be made without departing from the scope of the invention as

defined in the above examples of the possible embodiments.

Mode of Enablement

To enable this invention to perform, besides preparing the product and optimizing the

production technology, it is also important to characterize and test the quality of the

product for which purpose it is made. The biodiesel as prepared from a fatty acid fraction

devoid of erucic acid was therefore subjected to various tests as prescribed by BIS and

ASTM for biodiesel and the same were compared with biodiesel sample prepared from

mustard oil fatty acids (without separating erucic acid from it). The results as obtained are

tabulated below in Table 1. It was found, as expected, that the product obtained by fatty

acid fraction having no erucic acid in it gave a much superior product with lower viscosity

and better fuel characteristics than that was obtained from a fatty acid mixture obtained

from mustard oil from which the erucic acid was not separated.

A preliminary assessment shows that the biodiesel of this invention is way better than the

normal biodiesel prepared from mustard oil and can as well be used as automotive fuel

without much blending with petroleum diesel.

Dr Rajendra Prasad

IN/PA-1498

Agent for Applicant

7. Claims

We claim:

1. A process for obtaining biodiesel from fatty acids mixture (obtained from Indian

mustard oil from which erucic acid, the C 22:1 component has been previously

removed) comprising of:

a) mixing of fatty acids with methanol or ethanol in a ratio of

95:5 to 65:35,

b) adding to the mixture, sulphuric acid catalyst in amount of

0.1 - 5% on fatty acid weight basis,

c) mixing the reactants at 100-300 rpm to create finest possible

emulsion and optimum dispersion of fatty acids in the

alcoholic medium,

d) raising the temperature to 180-280°C and raising the pressure from to 800

kPa - 1000 kPa, and

e) stirring of the mixture for about 30 minutes to 3 hours.

2. A process for obtaining biodiesel from fatty acids obtained from Indian mustard oil

in which erucic acid, the c22:1 component is co-produced by distillation through

fractionating column from the fatty acid mixture of the mustard oil prior to

subjecting the mixture to trans-esterification.

3. A process for obtaining biodiesel from fatty acids of mustard oil as claimed in claim

1 wherein the said acid catalyst is sulphuric acid.

4. A process for obtaining biodiesel from fatty acids of mustard oil as claimed in claim

1 wherein

the trans-esterification reaction is carried out in a pressurized reactor by

passing hot live steam and its condensate water is continuously removed from

the reactor,

ii)

the pressure is maintained between 800 kPa - 1000 kPa and

iii)

acid catalyst (sulphuric acid) is periodically charged into the reactor at the rate

of 0.1 - 1% to make up for the lost acid with the condensed steam

5. A process for obtaining biodiesel from fatty acids of mustard oil as claimed in claim

1 wherein the biodiesel obtained at the end of the reaction which separates out in

upper layer is purified by filtration to remove suspended solid particles.

6. A process for obtaining biodiesel from fatty acids of mustard oil as claimed in claim

5 wherein said the filtrate containing biodiesel is subjected to evaporation to

remove excess alcohol which is reused in the reaction.

7. A process for obtaining biodiesel from fatty acids of mustard oil as claimed in claim

5 or 6 wherein the filtered biodiesel is subjected to washing with water to remove

traces of acid catalyst.

ABSTRACT

BIO-DIESEL FROM FATTY ACIDS OF MUSTARD OIL

A process and system of equipment and plant lay out for obtaining bio-diesel from

fatty acids from Indian mustard oil with the help of acid catalyst is disclosed. The

process co-produces erucic acid, a C22:1 component of the fatty acids mixture in a very

pure form as an additional bye-product besides glycerol. The biodiesel obtained from

the process is very clean and pure and conforms to the BIS standards. The bye product,

erucic acid together with glycerol renders the Bio-diesel production from this process

highly techno-economically viable.

Dr Rajendra Prasad

Dated 28th day of October 2015

IN/PA-1498

Agent for Applicant

Puri Oil Mills

Sheet 4 of 4

TEST RESULTS FOR BIODIESEL OF THIS INVENTION

TEST

BIS

ASTM

Biodiesel

Remarks

PROPERTY

Method

Limits

Method

Limits

(M)

(MFA - EF)

IS 1448,

Flash point °C)

Min 120

D-93

Min 130

167.3

175

P:21

Phosphourus

D-4951

Max

D-4951

Max

< 10 ppm

(ppm)

10 ppm

Water/Water &

D-2709

Max

D-2709

Max

Nil

sediment (ppm)

ISO 3733

500 ppm

500

ISO 6296

ppm

CCR 100%

D-4530 /

Max

D-4530

Max

0.012

Nil

(% mass)

ISO10370

0.050

Sulphated ash

ISO 6245

Max

D-874

Max

0.014

(% mass)

0.02

0.020

Kin. Viscosity at

ISO 3104

2.5

- 6.0

D-445

1.9

- 6.0

5.80

4.35

40 °C (cst)

Sulphur (ppm)

D-5453

Max

D-5453

Max

< 10 ppm

50 ppm

500 ppm

Cetane number

ISO 5156

Min 51

D-613

Min 47

60.4

Copper corrosion

ISO 2160

Max 1

D-130

Max 3

No.1

Neutralization

IS 1448,

Max 0.50

D-664

Max 0.80

0.04

0.07

Value

P:1/Sec1

Free glycerin

D-6584

Max

D-6584

Max

0.014

(%mass)

0.020

00.20

Total glycerin

D-6584

Max

D-6584

Max

0.014

0.016

(% mass)

0.250

0.240

Distillation

D1160

90% at

399 °C

358 °C

Temp. (°C)

360°C

Oxidation Stability

EN 41121

Min.6 hr.

5.84

0.52

Density at 15°C

ISO 3675

860 - 900

885

kg/m³

ISO 12185

Methanol, % by

EN14110

0.20

0.04

0.022

mass, max

*Fail ASTM - Biodiesel(M)

Biodiesel (M) = Biodiesel of Fatty acids of Mustard Oil

**Fail BIS

Biodiesel (MFA-EA) = Biodiesel of Fatty Acids of Mustard

Oil Devoid of Erucic Acid

Table I

Dr Rajendra Prasad

IN/PA-1498

Agent for Applicant