MASSIVE CO2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION WITH THE USE OF GRAVELS FROM OIL WELL DRILLING

Abstract

The present invention relates to the direct use by addition of drilling gravels residue from the oil exploration and production activities in the formulation of culture medium of unicellular organisms, increasing its growth rates, intensifying the CO.sub.2 biofixation, and generating value to this residue from of productivity gains expected by autotroph and mixotroph organisms (cyanobacteria, microalgae and macroalgae), as well as the production of bioproducts that can be generated through the concept currently described in the literature as biorefining. Algae are cultured using drilling gravel suspended in the culture medium together with the ability to grow by absorbing CO.sub.2. Mechanisms used by algae in soils and marine environments to tolerate salinity, sodicity and contamination of petroleum hydrocarbons provides wide adaptation to these conditions of abiotic stress and enables the destination without environmental impact, constituting a satisfactory solution for the destination of the gravel for oil exploration and production.

Claims

1- MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, characterized by comprising the following steps: (a) adding ground drilling gravels in concentrations ranging from 0.01% to 95%, preferably from 0.1%, based on mass/mass (kg/kg) or mass/volume (kg/L) units, in control culture medium or other culture medium or combinations of culture medium; (b) then, carrying out the inoculation of the strain in the inoculum concentration ranging from 1 mg/L to 1 g/L, preferably 50 mg/L, in tanks or other types of transparent containers subjected to natural or artificial sunlight with luminous intensity greater than 60 klux, ideally 120 klux, photoperiod from 8 to 14 hours, ideally 12 hours; (c) at the same time, carrying out another inoculation with similar concentration and under the same lighting conditions, using the same culture medium without drilling gravels, maintained as a control over time; (d) promoting bubbling to the system by aeration and supplying CO.sub.2 (without limitation of purity, preferably with 99% purity) through solenoid valve triggered by pH controller with electrochemical sensor, maintaining the pH between 6 and 7, preferably pH of 6.5 over 3 to 12 days of growth, preferably 6 days; salinity, measured with reference to the mass of sodium chloride, between 0.001 and 150 g/L, ideally 10 g/L; the temperature between 24 and 48° C., ideally at 34° C.; (e) performing daily observations under an optical microscope and macroscopic observations to attest the presence of healthy microalgae growing on medium containing gravel (P) and in the control medium (C).

2. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that the drilling gravel contains Al, Fe, Ca, Mg, Cu, Mn, Zn, Ni, Cr, P, K and Na and other chemical elements in its chemical composition.

3. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 2, characterized in that the drilling gravel is used ground in concentrations ranging from 0.01% to 95%, preferably 0.1%, having as reference the mass/mass (kg/kg) or mass/volume (kg/L) units.

4. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that the strain is composed of cyanobacteria, microalgae or macroalgae.

5. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 4, characterized in that the inoculation of cyanobacteria, microalgae and macrogalgae is carried out in inoculum concentration ranging from 1 mg/L to 1 g/L, preferably about 50 mg/L.

6. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that the control culture medium is BG11, or other culture medium, or combinations of culture medium.

7. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that it uses tanks or other types of transparent containers subjected to natural or artificial sunlight with luminous intensity greater than 60 klux, ideally 120 klux, and photoperiod from 8 to 14 hours, ideally 12 hours.

8. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that CO.sub.2 has no limitation of purity, preferably 99% pure.

9. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that the pH of the culture medium is between 6 and 7, preferably 6.5, over 3 to 12 days of growth, preferably 6 days.

10. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that salinity is measured with reference to mass of sodium chloride, between 0.001 and 150 g/L, ideally of 10 g/L.

11. MASSIVE CO.sub.2 BIOFIXATION PROCESS AND SEAWEED BIOMASS PRODUCTION, according to claim 1, characterized in that the temperature is between 24 and 48° C., ideally at 34° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in more details below, with reference to the attached figures which, in a schematic and non-limiting of the inventive scope, represent examples of their achievement. In the drawings, there are:

[0025] FIG. 1 illustrating the drilling gravel collection streams, the necessary logistical resources, and the massive CO.sub.2 biofixation process and biomass production by cyanobacteria, microalgae, or macroalgae, according to the present invention;

[0026] FIG. 2 illustrating the microalgae Desmodesmus sp. at the beginning of the experiment, after inoculation (1000x magnification), where (P) is the reactor with drilling gravels and (C) the control reactor;

[0027] FIG. 3 illustrating the microalgae Desmodesmus sp. 72 hours from the start of the experiment (1000x magnification), where (P) is the reactor with drilling gravels and (C) the control reactor;

[0028] FIG. 4 illustrating the microalgae Desmodesmus sp. after 144 hours from the beginning of the experiment (1000x magnification), where (P) is the reactor with drilling gravels and (C) the control reactor;

[0029] FIG. 5 illustrating the general appearance of the crops throughout the experiment with agitation and CO.sub.2 injection, where the sample with addition of gravel is called (P) and the control sample is called (C);

[0030] FIG. 6 illustrating the general appearance of the crops two days after the end of the experiment, where the sample with the addition of gravel is called (P) and the control sample is called (C);

[0031] FIG. 7 illustrating the interconnection between the components of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0032] The massive CO.sub.2 biofixation process and algal seaweed biomass production, according to the present invention and illustrated in FIG. 1, comprises a conventional culture medium, oil drilling gravel, aeration bubbling, cyanobacterial, microalgae, or macroalgae culture and a pH regulator with trigger of CO.sub.2 by solenoid valve.

[0033] According to FIG. 1, considering all the offshore gravel collection scenarios, whether from actuality, whether from the reservoir phase, and zero disposal, in the gravel collection system (2) in the probe (1), the gravel associated or not with discarded drilling fluids is transferred directly to gravel/hybrid boats (3). The gravel/hybrid boats sail (4) to the receiving ports and berth for gravel unloading (5). Finally, they go by land transport (6) to be used in the formulation of algae culture medium.

[0034] Another form of transporting gravel associated or not to discarded drilling fluids is through the packaging in cutting box (9) on adapted transport boats (8) sailing (7) to receiving ports and berth for gravel unloading (5) and from there follow the same unpackaged transport route previously described.

[0035] Solar radiation (10) affects culture tanks (15) of seaweed biomass production, where they are placed cyanobacteria, microalgae or macroalgae inoculums (14) containing water and culture medium (12), adding drilling gravel (11) and CO.sub.2 (13) supplied from refineries (21), natural gas processing units (NGPUs) (22) and thermoelectric plants (UTEs) (23), which are consumed at a rate of 60 g of CO.sub.2/m.sup.2/day (16) and produce and release O.sub.2 at a rate of 40 g/m.sup.2/day (17), resulting in biofixation of approximately 200 kg of CO.sub.2 (18) and production of 100 kg of dry biomass (20) of seaweed origin (19).

[0036] To obtain seaweed biomass, the following steps are required: [0037] a) adding ground drilling gravel to the concentrations ranging from 0.01% to 95%, preferably from 0.1%, based on mass/mass (kg/kg) or mass/volume (kg/L) units, containing in its chemical composition Al, Fe, Ca, Mg, Cu, Mn, Zn, Ni, Cr, P, K and Na in BG11 control culture medium or other culture medium or combinations of culture medium; [0038] b) then, performing the inoculation of the strain (cyanobacteria, microalgae or macroalgae) in tanks or other types of transparent containers subjected to natural or artificial solar lighting (light intensity higher than 60 klux, ideally 120 klux), photoperiod from 8 to 14 hours, ideally 12 hours), in a low concentration of inoculum (ranging from 1 mg/L to 1 g/L, preferably about of 50 mg/L); [0039] c) at the same time, carrying out another inoculation with similar concentration and under the same lighting conditions, using the same culture medium without drilling gravel, maintained as a control over time; [0040] d) promoting bubbling to the system by aeration and CO.sub.2 supply (without limitation of purity, preferably with 99% purity) through solenoid valve triggered by pH controller with electrochemical sensor (glass electrode), maintaining the pH between 6 and 7, preferably pH 6.5 over 3 to 12 days of growth, preferably 6 days. The salinity, measured with reference to the mass of sodium chloride, between 0.001 and 150 g/L, ideally 10 g/L. The temperature between 24 and 48° C., ideally at 34° C.; [0041] e) performing daily observations under an optical microscope and also macroscopic observations to attest the presence of healthy microalgae growing in the bottle with culture containing gravel (P) and in the bottle with control culture (C).

[0042] A dynamic experiment was carried out with injection of CO.sub.2 for observing the behavior of the microalgae Desmodesmus sp. The following abiotic parameters were defined: salinity 10 g/L, luminous intensity 120 klux (photoperiod 12 hours/day), temperature 34° C., pH 6.5 for sample with gravel and control.

[0043] The strain used grew by absorbing CO.sub.2 and using the nutrients provided in the added mixture (drilling gravel + culture medium), allowing to obtain an increase in growth with increased productivity, as shown in FIG. 7.

[0044] Daily observations under an optical microscope (FIGS. 2, 3 and 4) and macroscopic observations (FIG. 5) attested the presence of healthy microalgae (Desmodesmus sp) with growth in the bottle containing gravel (P) and in the bottle control (C). After the end of the experiment, the bottles containing the cultures were kept without agitation for a week, having shown high stability in microalgae of the control culture and in the microalgae that grew in the medium containing gravel (FIG. 6).

[0045] At the end of the experiment, it was found that there was excellent growth of Desmodesmus sp with CO.sub.2 capture, using drilling gravel at a concentration of 1 g/L in BG11 culture medium. There was a difference observed across microscopy between the control sample and the sample containing gravel with regard to the amount of biomass generated. The sample containing gravel had a higher concentration cell with respect to the control sample.

[0046] Both samples were shown to contain cells in excellent physiological state in both conditions - with and without adding gravel to the culture medium. The microalgae Desmodesmus sp has demonstrated affinity with the culture medium containing this type of solid residue, which represents an innovative result in relation to the international literature. Quantitative experiments are needed to better understand the growth rates obtained by Desmodesmus sp subjected to contact with the gravel.

[0047] The present invention is not based on the CO.sub.2 biofixation, which generally occurs by microalgae, autotrophic macroalgae and cyanobacteria based on photosynthesis. The invention derives from the fact that these organisms have a higher growth rate when there is drilling gravel in the medium compared to the control sample. As a result, there will be a higher rate of CO.sub.2 biofixation and consequently greater production of biomass, leading to productivity benefits and operational lower costs and investment in crops associated with oil and gas industry.

[0048] It is worth noting that productivity is directly related to the area required for the microalgae culture. The higher the productivity achieved in the microalgae culture, the smaller the area required in the production tank installation and, consequently, the investment cost for implementing the technology.

[0049] Experiments were carried out that proved the good growth of microalgae (of various genera and species) under different cultivation conditions with the mixture of drilling gravel from oil wells and conventional culture medium, having been obtained excellent biomass quality for use with several purposes. There was an injection of CO.sub.2 throughout the cultures, proving the intensive biofixation of this compound over the course of algae growth. As mentioned above, the increase in productivity of algae biomass cultured with gravel drilling of E&P activities constitutes a process, which is the main object of the present invention.

[0050] It should be noted that, although the present invention has been described in relation to the attached drawings, this may undergo modifications and adaptations by persons skilled in the art, depending on the specific situation, but provided that it is within the inventive scope defined herein.