CN1032674A - A treatment method for improving the filterability of a polysaccharide-containing fermentation broth used as an auxiliary oil recovery - Google Patents

Abstract

Processing contains a kind of polysaccharide fermentation liquid to obtain the method for good filterableness.This method is by making polysaccharide liquid stand a Ultrafiltration, heats composition then again.Curve II shows that the filterableness of the polysaccharide liquid that is obtained is excellent.Can be applicable to do assistant recovery petroleum.

Description

The invention relates to a treatment method for improving the filterability of polysaccharide-containing fermented liquid. It also relates to the resulting improved fermentation broth and its use as a thickener for auxiliary recovery of petroleum.

The polysaccharide solution is obtained by a well-known fermentation method and is the product of the microbial action of polysaccharides, such as the production of Xanthane (Xanthane) belonging to the genus Xanthomonas, in the presence of a carbohydrate Compounds, especially glucose, were cultured in nutrient aqueous media.

For the cultivation of xanthan, Xanthomonas campestris can be used. For the cultivation of scleroglucan, Scléro-tium Rolfsii can be used; for the cultivation of Schizophyllane, Schizophyllum Commune can be used.

During fermentation, a polysaccharide broth containing about 0.5 to 4% by weight is obtained, in addition to salts, residual nutrients, cell or fungal residues and other insoluble components.

Filtration can be used to remove insoluble particles present in unprocessed polysaccharide solution. However, aggregates of macromolecules exist, which are pseudoplastic, difficult-to-filter substances that tend to plug the pores of subterranean structures during petroleum-assisted recovery operations. It is important to eliminate such aggregates or at least reduce their harmfulness.

There have been many proposals in this regard, as reflected in a large number of patent documents is one example.

For example, U.S. Patent 3,355,447 suggests heating xanthene liquor followed by filtration. U.S. Patent 4,299,825 suggests heating followed by ultrafiltration to obtain a purified and concentrated sugar solution. European patent EP 0,049,012 proposes ultrafiltration with or without enzyme treatment to obtain a concentrated xanthene solution.

European patents EP 0,140,724 and 0,140,725 suggest heating followed by concentration by ultrafiltration or with reverse osmosis (diafiltration). These patents state that ultrafiltration has no effect on the filterability or injectability of xanthene solutions.

The properties obtained by the above-mentioned methods are unsatisfactory, and therefore there should be a method for obtaining a fermented liquid having excellent filterability, especially stable filterability over time.

The method for processing polysaccharide liquid of the present invention comprises following two steps successively:

A) Perform ultrafiltration with a filter membrane with a cut-off molecular weight between 10,000 and 100,000, but preferably between 10,000 and 30,000. During the ultrafiltration process, each volume of polysaccharide Add at least one volume of water (or saline) to the solution, then filter this at least one volume of aqueous phase, and collect the part of the polysaccharide solution that does not pass through the filter membrane (retentate).

B) Heating the intercepted liquid obtained in step A), the heating temperature is at least 60°C, for example, it can be between 60-130°C.

Impurities that pass through the filter membrane can be discarded.

In the above ultrafiltration, impurities pass through the ultrafiltration membrane with water, and the obtained retentate can concentrate it into more effective polysaccharides than before treatment. But this is not the purpose of the present invention. The method of the present invention is to add water, preferably salt water, so that the polysaccharide in the intercepted liquid has the same concentration as the sugar liquid before treatment. A better treatment mode is to gradually add at least one volume of water or brine (for example, 1-100 grams of alkali metal salt per liter, expressed as Nacl meter), for example can be 1 to 10 volumes of water, but preferably 5 to 10 volumes, and then let it filter at least one volume of water, for example can be 1 to 10 volumes of water, but preferably with the added Almost the same volume of liquid. To achieve this result, the solution may be passed through multiple ultrafiltration chambers and/or the solution may be recirculated multiple times through the same ultrafiltration chamber in a continuous or batch manner. This type of treatment is commonly referred to as reverse osmosis (diafiltration).

However, after the described reverse osmosis method, the operation can be completed by various typical concentration methods, including ultrafiltration concentration method.

The priority conditions for implementing the present invention are described below:

In the ultrafiltration process, the concentration of the polysaccharide polymer is preferably 5 to 100 grams per liter, most preferably 15-30 grams per liter. Lower concentrations, such as at least 100 ppm are also possible. The choice of filter membrane is not a decisive factor, and excellent results can be obtained. For example, cellulose acetate membrane, ether cellulose membrane, polyamide membrane, polyolefin membrane, polystyrene membrane, sulfonated polystyrene membrane or similar membranes can be used. etc., the present invention is not limited to use which one of them.

When the polysaccharide liquid is subjected to ultrafiltration, it is more advantageous if it contains one or more alkali metals, for example, 1 to 100 grams per liter, and preferably 5 to 50 grams per liter, calculated as NaCl. For Xiangyi.

The polysaccharide solution can be subjected to a conventional pre-filtration to remove cell debris with a size greater than 20 microns, preferably greater than 1 micron.

In the ultrafiltration process, it is advantageous to select the pH value between 4 and 11, and the temperature can be between 10 and 50°C, preferably between 20 and 40°C.

The concentration of the polymer during heating is optionally within the above-mentioned limits, i.e. 5 to 100 g per liter, preferably 15 to 30 g per liter. Lower concentrations, as indicated above, are also acceptable.

The optimum duration of heating, which is related to the desired result and the properties of the polysaccharide, is usually between 1 and 60 minutes, preferably between 5 and 15 minutes for xanthene, and for scleroglucan and cleavage Phlellin is between 1 and 24 hours.

The following comparative examples illustrate the practice of the invention.

example 1

The crude fermented sugar liquor from Xanthomonas campestris was taken and diluted to a concentration of 380 ppm by weight, and the concentration of alkali metal, expressed as NaCl, was adjusted to 5 grams of NaCl per liter.

Three samples were taken from the resulting solution (viscosity at 30°C: 2 x 10 ^-3 Pa·s; concentration: 380 ppm by weight).

The first sample was heated to 110°C within ten minutes, then cooled to 30°C, and then tested for filterability.

According to the method of the present invention, the second sample is contacted with a cellulose acetate filter membrane with a cut-off molecular weight of 20,000, and ultrafiltration is carried out at 30°C; in each volume of the second sample to be filtered, successively Add five volumes of an aqueous solution containing 5 grams of NaCl per liter, and then filter five volumes of this liquid. The resulting retentate was subjected to the same heating and cooling as the first sample, and then tested for filterability.

The third sample was first heated and cooled as the first sample, then subjected to ultrafiltration at 30°C as the second sample, and finally the filterability test was carried out.

During the above treatment process, the first and third sample solutions both had the same viscosity, that is, 7× ^10-3 Pa·s at 30°C, while the viscosity of the second sample solution at 30°C was 7.7 ×10 ^-3 Pa·s.

＝5秒^-1）下，把聚合物溶液喷经三个平均孔径为5微米的微孔过滤器中，然后测定滤过体积（V）和在过滤器中的流动性下降比率（R）的关系。Filterability was tested at 30°C and a slight shear gradient (

= 5 seconds ^-1 ), spray the polymer solution through three microporous filters with an average pore size of 5 microns, and then measure the filtration volume (V) and the fluidity drop ratio (R) in the filter relation.

Curves Ia, IIa and IIIa correspond to the first, second and third samples, respectively. figure 1.

The fluidity drop ratio is the ratio of Δp of polymer to Δp of water, where Δp of polymer is the pressure loss of the polysaccharide solution and Δp of water is the pressure loss of the saline phase without the corresponding polysaccharide.

Example 2

The same solutions for the first and second samples in Preparation Example 1 were repeated, but the concentration of the brine was 100 grams per liter as NaCl.

The resulting solutions after treatment (curves Ib and IIb, respectively) have a viscosity of 8.5 x ^10-3 Pa·s.

Filterability tests were carried out on these two solutions (Figure 2). The results showed that only the second sample treated according to the method of the present invention did not suffer from fouling.

Example 3

The test was carried out on a raw sugar solution of scleroglucan. The unprocessed Sclerotinia fermented liquid is filtered to remove fungal residues with a size greater than 20 microns, and then the fermented liquid is diluted to a concentration of 600 ppm by weight with a solution containing 20 grams of sodium chloride per liter.

The solution obtained (Solution Ic) was then subjected to ultrafiltration at 30°C by contact with a cellulose acetate membrane with a molecular weight cutoff of 20,000, as described in Example 1. The retentate (IIIc) was heated to 90°C under atmospheric pressure for 48 hours. The solution (IIc) obtained upon cooling to 30°C was subjected to the same filterability test as described in Example 1. After the solution passes through three microporous filters with an average pore diameter of 5 microns, the relationship between its fluidity decrease rate and the filtration volume is measured.

Fig. 3 shows the test results of the untreated solution (Ic), the solution treated with ultrafiltration only (IIIc) and the solution treated according to the method of the invention (ultrafiltration followed by heating). It can be seen that the first two solutions quickly blocked the filter, while the R value of the solution treated by the method of the present invention was very constant, that is to say, excellent filterability.

Example 4

A fermentation broth of Xanthomonas campestris at a concentration of 15 g/l was heated at 110°C for 10 minutes and then cooled to 30°C. The fermentation broth (sample 1) was diluted with an aqueous solution of 5 g/l NaCl to a concentration of 550 ppm by weight. The viscosity of this solution was 9.7 x 10 ^-3 Pa·s.

The preparation of the second sample is to add the aqueous solution of 5 g/liter NaCl in the fermented liquid, and carry out ultrafiltration by the same condition of the second sample of Example 1. Then, the same heating and cooling as in sample 1 of this example were performed. The fermentation broth was also diluted to a concentration of 550 ppm by weight with a 5 g/L NaCl aqueous solution. The viscosity of this solution was 10.4 x 10 ^-3 Pa·s.

Both solutions prepared from Sample 1 and Sample 2 were tested for filterability (curves Id and IId of Figure 4, respectively). Fermentation broth treated according to the method of the present invention can be used to prepare solutions that do not foul up, which is not the case with untreated solutions.

Claims (11)

1, a kind of purpose is to improve the treatment process of the fermented liquid that contains polysaccharide of its filterableness, it is characterized in that:

A). fermented liquid is that filter membrane between 10,000 to 100,000 carries out ultrafiltration with a kind of molecular weight cut off at first, and each volume will be added the long-pending water of one at least by the fermented liquid of ultrafiltration in ultra-filtration process, and allow it filter at least one volume liquid and

B). then to a). the obtained trapped fluid of step is heated at least 60 ℃.

2, according to the process of claim 1 wherein that the molecular weight cut off of the filter membrane that adopted is between 10,000 to 30,000.

3, according to the method for claim 1 or 2, the polysaccharide liquid that wherein stands ultrafiltration and heating is xanthene (Xanthane) polysaccharide liquid.

4, according to the method for claim 1 or 2, wherein a).In the step, the polysaccharide liquid that each volume stands ultrafiltration will add the water or the salt solution of 1 to 10 volume, and allows it filter the liquid of 1 to 10 volume.

5, according to the method for claim 1 or 2, the polysaccharide liquid that wherein stands ultrafiltration and heating is Sclerotium gum (Scl é roglucane).

6, according to arbitrary method of claim 1 to 5, wherein stand the polysaccharide liquid of ultrafiltration and heating, contain a kind of an alkali metal salt at least, its concentration contains 1 to 100 gram in every liter of NaCl.

7, according to the method for claim 4 or 5, polysaccharide liquid wherein is Sclerotium gum liquid or schizophyllum abamectin liquid glucose, and the temperature of heating is 60-130 ℃, and the time is 1 to 60 minute.

8, according to the method for claim 3, polysaccharide liquid wherein is xanthene polysaccharide liquid, and Heating temperature is 90-110 ℃, and the time is 5 to 15 minutes.

9, according to arbitrary method of claim 1 to 8, wherein the filter membrane that is adopted is a cellulose acetate film.

10, according to arbitrary method of claim 1 to 9, polysaccharide liquid wherein is the crude polysaccharide liquid that contains cell residue.

11, according to arbitrary method of claim 1 to 10, wherein when ultrafiltration, to add salt solution.

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