BG64773B1 - Method for the production of a combustion mixture of biodiesel - Google Patents

Abstract

The method is used for the production of fuel for diesel engines. It improves the ecological characteristics of the fuel. The method includes the addition to esters of fatty acids of lower alcohols, produced in the re-esterification of vegetable oils with lower alcohols in the presence of a catalyst - hydroxide , of alkaline methanol with subsequent purging of the esters produced. To the esters, heated to 25-30 degrees C, which are from 50 to 100 vol.%, diesel fuel is added, from 0 to 50 vol. %. The vegetable oil includes 20% treated oil, 20 vol.% suet and 60% unrefined vegetable oil. The re-esterification of the fats is performed with lower alcohol, which is 19-20 vol.%, at temperature up to 50 degrees C in the presence of a catalyst - hydroxide of an alkali metal in quantity of 0.5-0.6%mass.

Description

The invention relates to a method for producing a blend of biodiesel and is used in the production of alternative fuels for diesel engines.

BACKGROUND OF THE INVENTION

It is known that when diesel fuel (gas oil) is burned, harmful sulfur oxides are emitted into the diesel engines which pollute the environment and therefore the sulfur content is limited to 0.05-5-0.3 wt%. On the other hand, low sulfur content in the diesel fuel impairs its lubricating properties, which increases the wear of the diesel engines.

It is known that used vegetable oils and animal tallow are used in the household and industry to pollute the environment.

EP 06355558 Publ. 25.01.1995 describes a method for producing a concentrated additive for basic diesel fuel consisting of a mixture of diesel fuel and biodiesel up to 50% by weight.

The patent proposes the use of methyl esters as an adjunct to low sulfur base diesel fuel in order to improve the lubricating properties of the fuel. However, this does not reduce the emission of harmful sulfur emissions into the air, as well as the use of polluting waste oils and fats (tallow).

SUMMARY OF THE INVENTION

It is an object of the invention to provide a method of producing a biodiesel fuel mixture that will provide a reduced content of harmful sulfur emissions and the use of waste polluting oils and fats.

The method for preparing a biodiesel fuel mixture involves the preparation of lower alcohol alcohol fatty acid esters obtained by the transesterification of lower alcoholic vegetable oils in the presence of an alkali methanol hydroxide catalyst with subsequent purification of the resulting esters.

According to the invention, biodiesel is obtained by mixing 20% by weight of waste vegetable oil, 20% by technical tallow and 60% by unrefined vegetable oil, heating the mixture to 100 ° C, keeping it at this temperature until evaporation of water, cooling to 45 g -5 ° C, precipitation and filtration at this temperature.

The filtered mixture is mixed with a mixture that is 19-5-20% by volume of the filtered mixture and consists of 0.5 wt% NaOH and 99.5 wt% methanol (pure alcohol). The mixture of NaOH and methanol was obtained by mixing for 15 min NaOH in methanol.

Mixing between the filtered mixture (oils and fats) and the mixture between NaOH and methanol is carried out by stirring at high speeds (400 + 500 rpm) for 45-5-50 min, then allowed to settle in for 72 h. The precipitated mixture is separated into two layers - an upper one consisting of vegetable oil-colored esters and a lower one consisting of glycerol and a dark brown color. The esters obtained are filtered. Purification of the esters from the catalyst is carried out by washing with water and 5% vinegar in an amount up to 10% vol, which brings the pH of the esters within the range of pH 6-7.

The combustion mixture according to the invention is a mixture of fatty acid esters, in an amount of 100 + 50% by volume, obtained by transesterification of oils and fats with lower alcohols (methanol) in the presence of a catalyst and diesel (gas oil) of 0+ 50 wt.% the mixing is carried out after heating the esters at 25-30 ° C.

Examples of carrying out the invention

Example 1

Mix 20 l of waste vegetable oil, 201 technical tallow, 60 l of unrefined vegetable oil in a container. The whole fat was heated to 100 ° C and held at this temperature for 30 minutes until the water evaporated. It was cooled to 45-50 ° C, then filtered.

In a second vessel, 201 methanol (methyl alcohol - 99% pure analysis) and 0.500 Kg NaOH (crystals) were mixed. The sodium hydroxide solution was added to the methanol by stirring until complete dissolution for 15 min. The mixture of sodium methoxide (NaOH and methanol) was added to 45-50 ° C fat and stirred for 45-50 min at 450-S-500 rpm. After precipitation, the esters are separated in the upper 5 and glycerin precipitates in the lower 5. The esters are a vegetable oil color and the glycerin is a dark brown color. The separated esters were clarified in 72 h.

The separation of the catalyst dissolved in the methyl esters is carried out by washing with water and 5% vinegar until the pH of the esters is reached to 6-7 pH.

Table 1

Indicators Value 1. Fluidity at 15'C 0.88 g / cm ² 2. Cetane index 49 3. Kinematic viscosity - mm ² / s 75 4. Distillation characteristics 50% off at 290'C and 90% dest. at 360 ⁱⁿ C. 5. Cold filter filtration temperature limit - max. -12 ° C 6. Sulfur, lead and coke residues are missing

Example 2

Mix 50% gas oil and 50% methyl esters (the fuel shown in Example 1) by pouring the gas oil into the purified methyl esters, which are at 30 ° C. The fuel complies with BDS, ISO and DIN, with 40% improved fat and 25% reduced sulfur content.

Example 3

Mix 75% biodiesel and 25% gas oil. The fuel complies with BDS, ISO and DIN. Improved lubricity by 28%, higher kinematic viscosity. Reduced sulfur content by 15%.

Claims

Claims (2)

1. A method for producing a biodiesel blend comprising the following steps: - preparation of fatty acid esters and lower alcohols in the presence of a catalyst - alkali metal hydroxide and further purification of the resulting transesterification; - addition of diesel fuel to the resulting pre-esterification, characterized in that a mixture of spent vegetable oil 20%, unrefined vegetable oil 60% and tallow 20% is used as the raw material for the esterification; the amount of lower alcohol is 19-20% vol. relative to the initial transesterification mixture, and the amount of catalyst is 0.5-0.6 wt. %. Method according to claim 1, characterized in that the pre-esterifier to which the diesel fuel is added is heated to 25-30 ° C and in an amount of 50 to 95% vol. compared to diesel. Publication of the Patent Office of the Republic of Bulgaria 1113 Sofia, 52-B Dr. GM Dimitrov Blvd.