CS196159B1 - Method for the separation of aqueous cultivating liquid from hydrocarbons containing biomass suspension - Google Patents

Description

The present invention relates to a method for separating an aqueous culture liquid from biomass suspensions obtained by culturing microorganisms from a hydrocarbon phase. In particular, the invention relates to a process in which the hydrocarbon phase is not consumed completely and, as is known, together with adhering microorganisms forms a floating phase of biomass, hydrocarbons and water after introduction of the culture medium into the sedimentation vessel.

Vyyniez can be used in plants in which liquid hydrocarbons are microbiologically transformed and separated by microorganisms.

Forcing microorganisms on the hydrocarbon source in the presence of an aqueous nutrient solution of known composition produces stable emulsions, the stability of which is due to the cells of the microorganisms deposited on the phase interface.

For the first separation of the liquid, it is known to use a simple spreading, decanting or creaming process. The culture liquid to be separated generally contains unused nutrients which are separated from biomass and hydrocarbons for further use.

For this purpose, in general the rosio mixture is withdrawn from the fermentoro and fed to a decanter vessel.

In the decanter, the biomass decantes almost completely along with the hydrocarbon phase and can be continuously withdrawn. At the bottom of the vessel, the culture kappaina is withdrawn continuously.

The floating biomass and hydrocarbon slurry, however, still contains a large proportion of the aqueous multi-fluid. In the known processes, this slurry is generally separated by means of plate separators into hydrocarbon, aqueous and biomass-enriched aqueous phases.

In order to keep the separation costs low, it is desirable to achieve as much as possible by decanting as much as possible the proportion of the aqueous culture liquid. Various routes have been tried and described in this respect. DT-OS 1 545 252 describes the separation of phases of the effluent from the fermenter by separating the bulk of the aqueous nutrient medium by decantation and subsequent addition, not least by name. 0 g / l of a metal salt, preferably an alkali metal halide, and a surfactant in a concentration of at least 0.5 g / l

In addition to scaling the substances with demilgating effect, it is also known to use flotation phenomena by introducing finely divided air.

However, these methods generally do not have the consequence that in industrial use there are additional costs for excipients or flotation devices. In addition, during flotation, there is a risk that the suspension becomes foamy due to the finely dispersed air and thus technically difficult to handle.

The purpose of the invention is to adjust the phase separation within decantation without the use of expensive auxiliary means and energy in such a way as to make it possible. as a result of the separation at the separation stage, it could be carried out without movement

4 larger products and separation operations to separators of uniform quality.

It is an object of the invention to facilitate the separation of the biomass phase from the other phases by a specific arrangement of decantation.

The above object is achieved by the fact that the separation of the suspensions is carried out according to the invention by decanning over the contact surfaces at a surface load below 10 cnv of suspension per 1 cm @ 2 of contact surface per hour at a suspension flow rate of 0.5 to 10 cm.min wherein the suspension contains 5 to 80% hmoo. The hydrocarbons have a distillation range of 100 to 400 ° C under standard conditions.

Surprisingly, it has been found that the structural properties of the suspension together with the wall effects, in particular the different wetting behavior of water and hydrocarbons to almost all material of the apparatus, can be achieved by strongly influencing the suspension, which effectively utilizes to significantly improve separation of the aqueous culture liquid from the above suspensions. When viewed microscopically, these suspensions are from an almost continuous aqueous phase in which drops of hydrocarbons of varying size and air bubbles are nearly rippled.

Microorganisms, such as yeast cells, adhere mainly to hydrocarbon droplets. Flaked clusters of carbohydrate drops and microorganism cells are also often observed. In addition, occlusions of water can again be observed. As a result, 'the microstructure of the suspensions' is very non-homogeneous, especially also in terms of density ratios. Due to their large proportion of hydrocarbons, the flakes have a lower density than the surrounding aqueous phase.

For example, quenching sms consisting of a Candida Guillermonddi microorganism on a 20% petroleum distillate boiling in the range of 220 to 380 ° C and an aqueous coolant liquid were bent into a beaker filled with saddle bodies, the mixture was dispensed within about 5 minutes. 50% of the aqueous phase of 50 vol. 7a of the biomass suspension. After a further 10 minutes the volume ratios did not change, i.e. no significant water separation was achieved. Can. however, observe the flat, slowly increasing, enclosures of the water in the suspension, but do not break the suspension downwards. If now the water is slowly added to the vessel with the bottom sampler so that the biomass suspension flows upwards, it can be observed that the flat enclosure of water on contact with the surfaces of the saddle bodies or the wall of the vessel increases / decreases slowly during flow and decreases to the bottom.

If the same experiment was repeated without the saddle bodies, it was clearly found that the flat occlusions of the water were carried away from the largest part of the slurry upwards. During further systematic work it was found that separation was increased. The choice of the wall area to the volume of the decanter vessel and the volume of the slurry stream can have a decisive influence on the coolant liquid.

The higher separation levels were achieved when additional contact surfaces were provided in the vessel. in the form of sheets, screens, saddle bodies, Rasc.hig rings or chips.

Peripheral processes appear to be more complex in nature, with hydrocarbons and / or non-MCOs absorbed in the monomoecular films. However, it appears that in the increased separation of the culture liquid up to twice as high under otherwise identical conditions, as will be shown in the following examples.

In addition to increasing the degree of separation, it was also observed that the proportion of large hydrocarbon droplets in the slurry substantially increased after passing through the decanter with additional contact surfaces, which certainly has a beneficial effect on the separation of water from the slurry.

The research has generally employed suspension flow rates in the decantation vessel of 0.2 to 10 cm / min, which are chaotic and aesthetic for these processes. I will write down the flow velocities that have a fundamentally unfavorable effect on this process, but the speed of the droplets in the suspension can be exceeded.

The velocity changes make the containers unreasonably large. However, it can be found that the internal structure of the cream suspension hardly deteriorates at these low speeds.

If, on the other hand, the disturbance is agitated by stirring, then an effective result is also not obtained, since the agglomerates again expand by stirring.

Examples

In the following table, examples of embodiments for the continuous operation of the decanter cell 1.1 with different internals are shown. In order to illustrate the result of the invention, column I of the table shows a control experiment without internals. technological parameters. The deletion cells represent a cubic vessel with an edge length of 1 m, at the bottom of which a pyramidal tip protrudes. At 0.3 m above the base edge, the product is fed through three distribution rings with drilled holes. The surface of the container is wiped by a chain-driven de-icing device, by means of which the dewatered suspension is conveyed to the pattern. The said cells are fed ninually with a culture mixture consisting of about 20% petroleum distillate boiling in the range of 220 to 360 ° C, 8.1% avasic cells / = x ca. 2.0% of yeast dry matter (and about 82% of a mechanically soluble culture liquid (water)) from a continuously fermenting fermenter. The feed rate was about 2 t / h. The duration of the experiment lasted about 120 hours. During the experiment, the separating layer was kept constant in the center of the vessel. Every two hours, the dehydrated suspension was analyzed for yeast dry matter to determine the degree of separation.

The following examples were investigated: EXAMPLE 1: Consolidation Experiment. Example 2: plates suspended at a distance of 0.1 m.

Example 4: a polyethylene chip (0.5 mm thick) was placed on the same floor, twisted from a 5-cis-diameter polyethylene rod polyethylene bar.

Results: 1 2 3. 4 yeast concentrate-dry matter * 3.01 3.52 4.02 5,51 water separation% 41.6 53.0 61.0 77.5 dry matter of yeast in a separate liquid L 0.016 0.015 0.015 0.014

The table shows an increase in the degree of deactivation with an increase in the contact area.

Claims (1)

A method for separating an aqueous culture liquid from hydrocarbon-containing biomass suspensions by decanting, characterized in that it is carried out over the contact areas at a surface load below 10 cm @ 2 of suspension per 1 cm @ 2 of contact surface per hour and at a flow rate of 0.5 to 10 cm · min 1 1, the suspension comprising 5 to 80% by weight of hydrocarbons having a distillation range of 100 to 400 ° C under normal conditions.