PROCESS FOR THE REMOVAL OF THE HEAVY OIL FROM TAR SAND (EITHER OIL/HYDROCARBON WET OR WATER WET DEPOSITS) AND THE CLEANING UP OF THE EFFLUENT
20170306241 · 2017-10-26
Inventors
Cpc classification
International classification
Abstract
A process for the removal of heavy oil/bitumen from oil/hydrocarbon wet and/or water wet tar sand. The tar sand is mixed with an inorganic liquid such as water or a treated effluent and an inorganic solid which is a silicate or metasilicate for a period of time sufficient for the inorganic liquid and the inorganic solid to interact and strip the heavy oil/bitumen from the tar sand. The process includes additional steps to produce clean heavy oil/bitumen and clear effluent.
Claims
1) A process for removal of heavy oil/bitumen from oil/hydrocarbon wet and/or water wet tar sand, comprising: mixing tar sand, an inorganic liquid e.g. water or a treated effluent and a first inorganic solid which is a silicate or metasilicate, or a combination thereof, for a period of time sufficient for the inorganic liquid and inorganic solid to interact and strip the heavy oil/bitumen from the tar sand.
2) The process of claim 1 wherein the tar sand, inorganic liquid and first inorganic solid are mixed in a mixing vessel at ambient temperature.
3) The process of claim 2, wherein the tar sand, inorganic liquid and first inorganic solid are mixed for a period of time up to 3 hours.
4) The process of claim 2 further comprising passing the mixture through one or more meshes which trap the heavy oil/bitumen having some clay and sand attached thereto, and recirculating into the mixing vessel effluent passing through the meshes until the mixing vessel is clear of sand and clay.
5) The process of claim 4 wherein the water or effluent passing through the meshes is a muddy mixture of clay with dense sand settled at the bottom thereof.
6) The process of claim 5 further comprising washing the heavy oil/bitumen with water or treated effluent to remove more of the clay and sand attached thereto.
7) The process of claim 6 wherein the heavy oil/bitumen is washed at a temperature not higher than 58° C.
8) The process of claim 6 further comprising adding to the washed heavy oil/bitumen a diluent and a second inorganic solid to strip all solids and liquids from the heavy oil/bitumen and to react with the first inorganic solid to precipitate any solids/clay from the effluent so that it is clear.
9) The process of claim 8 wherein the second inorganic solid is a chloride, sulphate or nitrate.
10) The process of claim 8 whereby the resulting solids/clay are environmentally safe and can be released into the environment
11) The process of claim 9 wherein the diluent is an organic liquid e.g. toluene, a condensate or d-limonene.
12) The process of claim 8 whereby the minimum oil recovery is 80%.
13) The process of claim 8 further comprising centrifuging the heavy oil/bitumen for up to 30 minutes at a minimum of 5,000 rpm to produce clean heavy oil/bitumen.
14) The process of claim 8 further comprising centrifuging treated effluent for up to 15 minutes at a maximum of 5,000 rpm to recover treated effluent and any oil in the effluent.
15) The process of claim 8 wherein an acid is added to the treated effluent to bring the pH to 6-8 so that the effluent meets environmental standards and can be released into the environment or reused.
16) The process of claim 15 wherein the acid is hydrochloric acid.
17) The process of claim 8 where greater than 75% of the treated effluent can be recovered.
18) The process of claim 1 wherein the oil wet or water wet tar sand is 30-65% by weight of the mixture, the inorganic liquid is 30-65% by weight of the mixture, and the first inorganic solid is 0.05-5% by weight of the mixture.
Description
BRIEF DESCRIPTION OF THE DRAWING
[0048]
DETAILED DESCRIPTION OF THE INVENTION
[0049] Into a mechanical mixer is placed the following:
[0050] 30-65% by weight of oil wet or water wet tar sand
[0051] 30-65% by weight of an inorganic liquid e.g. water at ambient temperature or reused inorganic liquid at ambient temperature
[0052] 0.05-5% of a silicate or metasilicate
[0053] Mixing time is up to a maximum of 3 hours. However, for very weathered/deteriorated samples a mixing time up to a maximum of 6 hours can be used.
[0054] This process could be batch or continuous.
[0055] Weight of the second inorganic chemical e.g. chlorides or nitrates or sulphates is 0.05-5% by weight. The amount of 37% hydrochloric added being 0.05-1.5% by weight.
[0056] 6) Results—Oil
[0057] Tar Sand samples used were: [0058] Weathered (deteriorated) water wet tar sand from Trinidad and Tobago—TT. A large sample size of this tar sand was exposed to the elements e.g. rain for >24 hrs at an average temperature of 30° C. A 5 gal sample was then taken from the under surface of the load and stored in the lab. Use was made of the sample as needed—the sample was not refrigerated. [0059] Oil wet tar sand obtained from the USA-OW. This sample was also not refrigerated, and was used within a year of receipt. This sample was taken from different locations which were then mixed together for homogeneity. [0060] Water wet tar sand obtained from Canada-WW. This sample was also not refrigerated, and was used within 2-3 months of receipt. This sample was taken from different locations which were then mixed together for homogeneity.
[0061] Due to the extreme weathering of the TT sample, this was used as a reference only, with the results below pertaining only to WW and OW.
[0062] 6A Moisture Content
[0063] A 30 g sample each of OW and WW was removed from the larger samples and air dried in the lab. Each sample was brought to constant weight, and the % moisture obtained.
TABLE-US-00001 Tar Sand Type % Moisture OW 1.96 WW 7.48
[0064] 6B Maximum Theoretical Yield on Air Dried Tar Sand Samples
[0065] Once constant weight was arrived at, each tar sand sample was ashed using ASTMD 2415.
[0066] This procedure yields the maximum theoretical yield as ashing removes not only the bitumen/heavy oil, but also any water of hydration, volatile matter from clay and other minerals and other extraneous organic matter (Attwooll, A. W. & Broome, D. C. , 1962, Trinidad Lake Asphalt; Third Edition (Private Circulation), London: The Baynard Press.)
[0067] This would give rise to a decrease in the % inorganics (clay/sand) and an increase in the % organics. This invention therefore uses all the organic material which is removed after ashing as the bitumen/heavy oil portion—hence the maximum yield.
TABLE-US-00002 % Ash (inorganics) results are for duplicate experiments, with the average of the Tar Sand Type 2 experiments in brackets % Organics (subtraction) OW (air dried) 90.00, 89.01 (89.55) 10.45 WW (air dried) 89.36, 89.40 (89.38) 10.62
[0068] 6C Actual % Yield
TABLE-US-00003 Actual Wt. of heavy Tar Sand Type Density (g/cc)** API Gravity** oil/bitumen (g)** OW 0.997 10.32 129.93 WW 1.013 8.02 141.96 **Results obtained by independent testing.
TABLE-US-00004 Maximum Theoretical Yield of Wt. Of Tar sand Wt. of Bitumen/Heavy the Process Tar sand Type Used (g) Oil Expected (g) (%) OW 1534 160.30 81.05 WW 1652 175.44 80.91
[0069] The figures for both the OW and the WW samples are the minimum yields which would be obtained when use is made of the process stated herein.
[0070] It is a well-known fact that water wet samples weather (deteriorate) faster than the oil/hydrocarbon wet tar sand and refrigeration is required after mining to halt this deterioration. Once weathered it becomes more difficult to extract the heavy oil/bitumen from the tar sand and yields are reduced. The samples used in this patent were not refrigerated so as to test the process described herein on the most challenging samples. Samples that had been refrigerated, would have been less weathered and would produce higher yields than described in the table above.
[0071] Additionally, the moisture content was not considered in the actual yields. This was due to the fact that when each tar sand type is being processed, the samples of tar sand used will each have different moisture levels.
[0072] 6D Efficiency of Process
[0073] After extraction of the heavy oil/bitumen from the tar sand (oil wet and water wet), treating of the effluent and centrifugation, the solids (clay/sand) from the tar sand, were then air dried. A representative portion of each inorganic (clay/sand) sample from the tar sand was ashed as per ASTM D2415. This would remove any residual organics left in the tar sand and would give an indication of the residual organics left in the tar sand after extraction of the heavy oil/bitumen giving an efficiency of the process.
TABLE-US-00005 % Ash (inorganics) results are for duplicate experiments, with Type of tar sand the average of the 2 experiments in % Organics (air dried) brackets (by subtraction) OW 95.99, 95.79 (95.89) 4.11 WW 94.81, 93.63 (94.22) 5.78
[0074] The efficiency of the process is 94-95% for water wet tar sand and 95-96% for oil (hydrocarbon) wet tar sand.
[0075] Results—Effluent
[0076] As stated, the function of the second inorganic chemical which is used in the process is two-fold, to remove the clay/sand/water which is still in the oil and just as importantly to produce an instant reaction which precipitates the clay.
[0077] There is immediate separation of the dirty effluent, and crystal clear water (though with a yellow tinge) can be observed rising to the top.
[0078] The mixture is centrifuged at a maximum of 5000 rpm for a maximum of 15 minutes.
[0079] To ensure the quality of the water the BOD (Biological Oxygen Demand) and the COD (Chemical Oxygen Demand) values were obtained for both the WW and OW tar sands.
[0080] 6E BOD & COD-OW
TABLE-US-00006 EMA Permissible Parameter Level for Inland Name Method Used Units Results** Surface Water BOD5 SMEWW 5210B mg .Math. L.sup.−1 16.2 30 Chemical SMEWW 5220 D mg .Math. L.sup.−1 106 250 Oxygen Demand (COD) **Results obtained by independent testing pH of the tested effluent - 8.14 (Please note - the OW effluent was not diluted)
[0081] BOD & COD-WW
TABLE-US-00007 EMA Permissible Parameter Level for Inland Name Method Used Units Results** Surface Water BOD5 SMEWW 5210B mg .Math. L.sup.−1 10.8 30 Chemical SMEWW 5220 D mg .Math. L.sup.−1 312 250 Oxygen Demand (COD) **Results obtained by independent testing pH of the tested effluent - 7.32 (Please note - the WW effluent was not diluted)
[0082] The BOD results of the effluent from each tar sand type clearly show that there is little or no carry over of oil/diluent in the effluent.
[0083] The COD results are believed to be caused by any oxidisable soluble salts present in the tar sand solids.
[0084] 6F Volume of Water Recovered
[0085] The solids present in the tar sand (oil wet and water wet) have an affinity for water and even after centrifugation, each residual solid type still contained some water.
[0086] At this point, the clay/sand present in each tar sand type is a wet solid and can be placed back into the environment.
[0087] In an attempt to recover even more clean water, each residual solid was compressed (for e.g. by hand) and re centrifuged.
[0088] The results are as stated below:
TABLE-US-00008 % Recovery (hand % Total recovery % Recovery (centrifugation) compression)* results are for duplicate results are for duplicate experiments, results are for duplicate experiments, with the with the average of the 2 experiments in experiments, with the average of average of the 2 experiments Tar Sand Type brackets the 2 experiments in brackets in brackets WW 67.12, 70.11 (68.62) 6.90, 6.67 (6.79) 74.02, 76.78 (75.4) OW 73.56, 75.11 (74.34) 2.75, 2.13 (2.44) 76.31, 77.23 (76.77) *One would expect mechanical compression to lead to even further recovery than that obtained by hand compression
[0089] 6G 70% of the water used can be recovered with 15 minutes from the WW tar sands. The rest can be recovered within the time frame that is required for additional compression to occur. The BOD and COD of the resulting water are stated herein.
[0090] 73-75% of the water used can be recovered within 15 minutes from the OW tar sands. The rest can be recovered with the time frame that is required for additional compression to occur.
[0091] The BOD and COD of the resulting water are stated herein.
[0092] 6H As the water loss with each tar sand type is significant; an attempt was made to ascertain where the loss could have occurred.
[0093] After centrifugation and squeezing etc., the clay/sand from each tar sand type was air dried to constant weight in the lab.
TABLE-US-00009 Tar Sand Type Weight Before (g) Weight After (g) % Moisture OW 207.12 173.62 16.17 WW 210.61 178.95 15.03
[0094] The loss could therefore be simply water absorbed/absorbed by the clay and/or both determinate and indeterminate errors.
[0095] 6I To produce one barrel of heavy oil using the process described herein requires 4.68 barrels of water of which 75% is recovered and becomes reused effluent which meets the BOD and COD specifications stated above, and 25% is added (make-up) water.