DD147365B1 - METHOD FOR PRODUCING SULFUR-PACKED PETROLEUM AND PETROLEUM FRACTIONS - Google Patents

Description

Field of application of the invention

The invention relates to a process for sulfur removal from petroleum and petroleum fractions. The process is used in the petroleum-processing industry.

Characteristic of the known technical solutions

Petroleum and petroleum fractions contain more or less extensive admixtures of undesirable compounds such as mercaptan, sulfide and thiophene organic sulfur compounds.

With the use of petroleum and petroleum fractions, these non-hydrocarbon compounds are corrosive, reduce the activity of petroleum refining catalysts and petrochemicals and, when the petroleum fractions are used to produce energy, produce high air pollution through the formation of sulfur dioxide.

Usually, the removal of these undesirable substances by catalytic hydrodesulfurization takes place at high temperatures, high pressure and in corrosion-resistant plants.

However, the cost of such hydrocatalytic processes is too high. In addition, the application of hydrocatalytic desulfurization is not possible for all petroleum fractions.

Furthermore, microbiological processes for aerobic and anaerobic desulfurization with direct involvement of microorganisms are known. (US 2,975,103, US 2574070, US 2641564, Jap. 7023831, DD 108553, DD 138780) In the known patent specifications, the petroleum compounds which contain sulfur in the molecule are removed by microbiological means by oxidation or hydrogenation. The end product of microbial metabolism is mainly sulphates or hydrogen sulphide.

For the microbiological desulfurization u.a. the following fermentation conditions are given: a temperature range of 298-348K, a pH range of 6.0-8.5; a pressure range of 0.98-294 bar; a redox potential of -200 to -40mV and the use of a synthetic nutrient medium of different composition.

The fermentation is carried out in variously constructed fermentors depending on the given fermentation regime. The activity of the microorganisms used in these methods is determined by certain additions to the nutrient medium such as by growth stimulators, by calcium carbonate, carbohydrates u.a. affected.

To improve the contact between the microorganism, nutrient medium and the product to be desulphurised, one also works with surfactants.

According to DD 108533 and 138780, the purification of the petroleum is realized by a microbiological process in which the catalytic effect of the whole living cell or living replicable parts of it is utilized to decompose the organic sulfur compounds of the petroleum. The bacteria used for desulfurization according to DD 108533 contain several enzyme systems, such as the degradation of hydrocarbons, the oxidation of sulfur compounds and the like. These enzyme systems work only when the catalytic effect of the whole living bacterial cell is utilized. According to DD 138780 also the catalytic effect of the whole living cell is used for desulfurization. The activation of the necessary for the process, externally supplied technical hydrogen is carried out by the desulfurization culture used.

The previously known methods for the microbiological desulfurization of petroleum and petroleum fractions have the disadvantage that the microorganisms consume a certain amount of product to be desulphurised for the growth and maintenance of their metabolic processes and thus a loss of petroleum or petroleum fractions occurs.

In addition, the separation of the desulfurized product from the aqueous nutrient medium and the microorganisms is associated with high technical complexity. A major shortcoming of microbiological processes is the low desulfurization performance per unit of time.

Object of the invention

The aim of the invention is to win low-sulfur petroleum or petroleum fractions with the least possible technical effort.

Explanation of the essence of the invention

The object, which is solved by the invention, is that low-sulfur petroleum or petroleum fractions are produced without direct contact with the microorganisms takes place.

According to the invention low-sulfur petroleum and petroleum fractions are obtained when a biochemical reaction between the petroleum or a petroleum fraction and a desulfurizierenden enzyme system is carried out using petroleum or a petroleum fraction with a buffers containing aqueous solution with the addition of sulfur-free surfactant and iron-Il chloride with the desulfurizierenden enzyme system so is dispersed, that Reynolds numbers are generated in the range of 3 · 10 ^{2 to} 4 · 10 ⁴ and simultaneously carried out with a fumigation with technical hydrogen.

For the generation of turbulence in the reactor, no additional technical devices, as they are often described in microbiological processes, necessary. The enzymatic system isolated from anaerobic microorganisms, hydrosenase, activates the hydrogen necessary for the process and thereby the carbon disbond of the sulfur compounds contained in petroleum or in the petroleum fractions is selectively cleaved in short reaction times and desulfurization is effected, the catalytic effect of non-living, non-replicable parts the cell is used.

The contact time between the enzyme system and the petroleum or petroleum fraction must be 1200 to 7200s.

The desulfurizing enzyme system is preferably obtained from a mixed culture of obligate anaerobic bacteria in particular of the genus Desulfovibrio in a known manner.

The use of the enzyme system takes place as a crude enzyme extract. The biochemical reaction taking place at atmospheric pressure and at normal temperature is carried out in a reactor which is simple in terms of process, the following reaction conditions being observed:

PH of the aqueous buffer solution containing 7.5 to 8.5

• Concentration of ferrous chloride 0.5-1.5g / l

Activity of the desulphurizing crude enzyme extract when used in the reactor, at least 2 moles of hydrogen consumption per gram of enzyme nitrogen and 3600s

• ratio of petroleum or petroleum fraction to total aqueous phase 40-70% by mass to 60-30% by mass

• Use of 0.1-0.8kg of crude enzyme extract per 100kg of petroleum or petroleum fraction

After completion of the enzymatic reaction, the low sulfur petroleum or petroleum fraction is separated from the aqueous phase by separation at temperatures of 333-342K. The resulting in the biochemical reaction exhaust gases still contain a substantial portion of unreacted hydrogen. This hydrogen can be used again in the enzymatic process after separation of the sulfur-containing associated gases.

embodiment

The process according to the invention is explained in more detail with reference to the following example:

In a biochemical reactor operating continuously under atmospheric pressure and at normal temperature, petroleum, an aqueous solution containing buffer substances with the addition of 0.5 kg / m ³ surfactant of the polyethylene-propylene adduct type; 1.27 kg / m ^{3 of} ferrous chloride and 0.2 kg / 100 kg of crude oil desulphurizing crude enzyme extract so emulsified that a Reynolds number of 6 × 10 ³ could be obtained.

As the desulfurizing enzyme system, intracellular enzymes of bacteria of the genus Desulfovibrio were used. The crude enzyme extract has been recovered in a known manner from a mixed culture containing predominantly the obligate anaerobic bacteria of the genus Desulfovibrio, which had been isolated from wastewater sediments.

The activity of the desulphurizing crude enzyme extract when used in the reactor was 2.4 moles of hydrogen consumption per gram of enzyme nitrogen and 3600 seconds.

By the composition of the buffer substances contained aqueous solution, a concentration of 0.186 kg / m ³ potassium hydrogen phosphate

1.097kg / m ³ disodium hydrogen phosphate and a pH of 7.6.

The ratio of petroleum to aqueous phase was 65:35 by weight.

The technical hydrogen necessary for the biochemical reaction was fed to the system by fumigation, the fumigation intensity being 90m ^{3 of} hydrogen / t of petroleum and 3600s.

The contact time of the petroleum with the crude enzyme containing aqueous phase in the reactor was 3600s. The leaving the reactor two-phase system has been separated in a separation stage at 338 K. From the exhaust gases produced in the biochemical reaction, the unreacted hydrogen was separated and reused in the reaction.

Under these reaction conditions, the oil used could be desulfurized to 63%.

The results of the method according to the invention are compared in the following table with the results of known methods.

invention microbiological hydrogens method according to DD138780 Hydrokat. Ver fractions method according to USP 2641584 nachJap.4523831 go to no information DE 2054771 - Petroleum, petroleum fractions petroleum Light oil and Petroleum, petroleum fractions heavy petroleum dibenzothiophene, -3- 147 365 anaerobically oil hydrierend Table: Comparison of the results of the process according to the invention with known desulphurization processes 40-70 to 60-30 10:90 10-40 to 50-60 catalytic parameter 5 - Enzymatically-bio 20-75 aerobic anaerobically 420-435 use products chemical 1-300 at 150Kp / cm ² 2 microbially produced 4 5 technical hydrogen hydrogen Ratio one normal temperature no information 28 normal temperature not specified rate products / nutrient normal pressure no information normal pressure normal pressure > 55 solution techn. hydrogen air technical process principle hydrogen 1-2 168 48-56 Nährlösungsbe > 60 7-25 > 50 constituents temperature print used gas phase Residence time (h) desulfurization power %

Claims (2)

Invention claim: 1. A process for the preparation of low-sulfur petroleum or petroleum fractions at atmospheric pressure and normal temperature, characterized in that the petroleum or petroleum fraction containing a buffer substances, ferrous chloride and desulfurizierenden enzyme system containing aqueous solution is dispersed so that Reynolds numbers in the range from 3 × 10 ^{2 to} 4 × 10 ⁴ , a gassing with technical hydrogen takes place and contact times between enzyme system and crude oil or petroleum fraction are maintained at from 1200 to 7200 s. 2. The method according to item 1, characterized in that a ratio of petroleum or petroleum fraction to aqueous solution of 40-70 Ma .-% to 60-30 Ma .-%; a pH of 7.5-8.5; a content of ferrous chloride of 0.5-1.5 g / l aqueous phase and the desulfurizierende enzyme system, which is obtained from a mixed culture of obligate anaerobic bacteria of the genus Desulfovibrio, as crude enzyme extract of at least 2 moles of hydrogen per gram Enzyme nitrogen and 3600s is used.