Abstract:
The production of biodiesel is labor and time intensive. A first catalyst and a second catalyst were used for a two step transesterification of used oil to make biodiesel. The ratio of second catalyst and alcohol determines the outcome of good quality biodiesel that meets the ASTM standards. Several experiments were conducted to find optimal second catalyst, second catalyst alcohol ratio, and different times for adding second catalyst and alcohol either in sequence or simultaneously. Potassium hydroxide as a second catalyst and methanol as an alcohol, in a specific ratio calculated based glycerin value dictated the final volume. Specific ratio of catalyst and alcohol, when added together for a short duration lasting for minutes, instead of hours, produced superior quality biodiesel. The biodiesel production was stable and consistent. The production time was reduced considerably. Truncated method of producing biodiesel has tremendous cost and time advantage.

Description:
FIELD OF TECHNOLOGY 
       [0001]    This disclosure relates generally to a process and a method of making biodiesel below American Society for Testing and Materials (ASTM) required standards. The invention further discloses the ratio optimization of potassium hydroxide (KOH) concentration and methanol, optimal time for adding the catalyst and alcohol and method of removing of water to make clean biodiesel. 
       BACKGROUND 
       [0002]    Rapid growth in population coupled with industrial and technological developments are leading towards the depletion of fossil fuel resources in today&#39;s world. Biodiesel, an alternative diesel fuel, is a promising low cost, non-toxic and eco-friendly alternative. The process of making biodiesel is a method for developing an alternative renewable energy resource. 
         [0003]    Many attempts are being made to utilize commercially used mixed oils to make biodiesel. However, many technical problems have to be overcome by possible treatments such as dilution with a suitable alcohol, emulsification, pyrolysis and transesterification. 
         [0004]    Transesterification is a process of reacting a triglyceride such as mixed commercially used oil with an alcohol, usually methanol, in the presence of an alkaline catalyst to produce fatty acid esters (biodiesel) and glycerol. Alkaline-catalyzed transesterification process is normally adopted for biodiesel production because alkaline metal alkoxides and hydroxides are the most effective transesterification catalysts compared to the acid catalysts, although for economic reasons hydroxides are more often used. Transesterification occurs at a faster rate in the presence of an alkaline catalyst than in the presence of the same amount of acid catalyst. Sodium alkoxides (sodium methoxide, for example), Sodium methylate, KOH and NaOH are the most efficient catalysts used for this purpose. A number of manufacturers have identified the important variables that still affect the transesterification reaction, particularly, the reaction temperature, the type and amount of catalyst, the ratio of alcohol to mixed commercially used oil or vegetable oil, the mixing intensity and the reaction time, etc. These variables are a limiting factor is getting ASTM standard quality consistently and reproducibly at an industrial scale. 
         [0005]    The typical process of transesterification reaction is shown below: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0006]    The time required for production of biodiesel is currently very long and the yield quality struggles to meet the ASTM standards. There is a need to optimize the biodiesel production process specifically the transesterification step to yield high quality biodiesel and reduce the biodiesel production time, so that the average producer is capable of producing high quality biodiesel for average consumers at a lower cost. 
       SUMMARY 
       [0007]    The invention discloses a process and method for making a biodiesel and optimal catalyst concentration and time for achieving the same. 
         [0008]    In one embodiment a two step transesterification method may be performed to obtain higher biodiesel yield. In another embodiment, both steps may have same and/or different catalysts. 
         [0009]    In one embodiment, a process to calculate a formula was developed to calculate the amount of catalyst and the alcohol to be used. As a first step free fatty acid number was estimated by a conventional test used in the industry. In another embodiment, glycerin value was used to optimize the percentage ratio calculation of the catalyst to be used. The glycerin value multiplied by a percentage represents the gallons of catalyst to be used on an industrial scale. The catalyst amount multiplied by the glycerin value for used oil equals the gallons of alcohol to be used. 
         [0010]    In one embodiment, a two step transesterification method to produce biodiesel is disclosed. The first step uses sodium methylate or sodium methoxide as a catalyst with methanol as an alcohol for the transesterification process. The subsequent step  2  may use KOH as a catalyst and methanol as an alcohol for producing biodiesel. 
         [0011]    In another embodiment, the amount of KOH after the transesterification was determined and the ratio of methanol to KOH is disclosed. In another embodiment, the time of mixing the catalyst KOH to the used oil is disclosed. 
         [0012]    In one embodiment, the mixing step of the KOH and the methanol to the used oil to make biodiesel is disclosed. The mixing of KOH and methanol to the used oil may be done sequentially or simultaneously. In one embodiment, the used oil was preheated to a certain degree so that transesterification may happen rapidly and the separation of glycerin and water is smoother. 
         [0013]    In another embodiment, removing of water after the washing of biodiesel step is disclosed. This additional step ensures removal of any remaining water. The biodiesel is passed through the column of water adsorbent material. The water may adhere or get absorbed in the material and the cleaner biodiesel may be collected from the top of the column. The water may also settle at the bottom of the column due to gravity and may be removed. 
         [0014]    In one embodiment, a method of producing a biodiesel having low ASTM values and performing ASTM tests after the experiment to determine the acceptable quality of the produced biodiesel is disclosed. 
         [0015]    In one embodiment, a process of making biodiesel below required ASTM value is disclosed. In another embodiment, a two step process of making a cleaner biodiesel using two different catalysts is disclosed. In a further embodiment, a process of removing the water by passing the produced biodiesel through a water absorbent or adherent material for three times in sequence is disclosed. 
         [0016]    The methods and processes disclosed herein may be implemented in any means for achieving various aspects, and may be used to produce biodiesel. Other features will be apparent from the accompanying drawings, tables and from the detailed description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Example embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: 
           [0018]      FIG. 1  is a Prior art view of the Biodiesel formation by using a mixed methanol-catalyst combination in the conventional method. 
           [0019]      FIG. 2  is a method of making and process of producing biodiesel by using a sequential step process of adding the catalyst and methanol for a fixed time sequentially for a shortened period. 
           [0020]      FIG. 3  is a method of making and process of producing biodiesel by using a simultaneous step process of adding the catalyst and methanol for a fixed time sequentially for a shortened period. 
       
    
    
       [0021]    Other features of the present embodiments will be apparent from the accompanying tables and from the detailed description that follows. 
       DETAILED DESCRIPTION 
       [0022]    Several methods and processes for production of biodiesel (alternative renewable energy resource) are disclosed. Although the present embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments. 
         [0023]    The instant application discloses that the claimed invention materially enhances the quality of the environment by contributing to development of renewable energy resources from used oil, such as restaurant oil, recycled oil etc. This application discloses an alternate energy source for conserving existing energy and making low cost biodiesel from used oil in a shortened period of time. The resultant biodiesel also meets and exceeds the ASTM standard required by the biodiesel industry. The instant application uses a two step biodiesel production process and describes a method and process of making low cost biodiesel. The basic catalyzed production of biodiesel generally occurs using the following steps as shown in  FIG. 1  as prior art and the instant invention is shown in  FIG. 2  and  FIG. 3  and discussed in the following description. 
         [0024]    As shown in  FIG. 1 , step  1 , the vegetable oil, used cooking oil and/or animal fat is used as a starting material and will be represented as “used oil  102 ” throughout the application. The used oil may be but not limited to restaurant used oil, recycled oil and deep fried oil. The used oil  102  is allowed to sit for several hours in order to separate the solid particle contaminants by sedimentation process  106 . The oil may be filtered to remove particles. The particles may be food particles, soap suds and/or any other solid particles. Once the contaminants are removed the oil is transferred to another container and heated  108  between 127-138° F. 
         [0025]    Free fatty acid values are estimated using conventional laboratory tests, for example Saftest, to determine the amount of catalyst and alcohol to be added to transesterification reaction for step  1 . Simultaneous mixing  109  of alcohol  104  and catalyst  108  may be done for several hours. The catalysts that may be typically used are sodium hydroxide (caustic soda) or potassium hydroxide (potash) or sodium methylate. The oil is mixed with the alcohol using a standard agitator or mixer. The predetermined weight of catalyst and premeasured amount of methanol may be added for a fixed amount of time. In this first step the catalyst may be sodium hydroxide (NaOH) or sodium methylate. The mixture may be continuously agitated using mixer  110  and the transesterification reaction may be conducted for 5-8 hours. The resultant glycerin  112  and biodiesel  121  are separated. The non transformed used oil  127  may be used in step  2 . 
         [0026]    As a next step ASTM test  105  may be performed for the used oil  127  before step  2  in order to determine the glycerin value for calculating the amount of catalyst  108  and alcohol  104  that needs to be added for transesterification process. Oil may be heated  140  throughout this procedure. The catalyst may be the same catalyst as used in the step  1 . 
         [0027]    The predetermined weight of catalyst  108  and premeasured amount of methanol  104  may be added ( 109 ) rapidly for 5-8 hours or longer. The resultant biodiesel  121 B is passed through a water spray  116  chamber and ASTM value estimation  111  for biodiesel  121 B is done prior to using it as a fuel  125  for a vehicle  130 . This procedure is long and water content is not fully removed. 
         [0028]    The novelty of the instant invention is using two different catalysts at different steps. As shown in  FIGS. 2 and 3 , in step  1  sodium methylate or sodium methoxide is used as a first catalyst for transesterification. As shown in  FIG. 2  in step  2 , in the instant invention the novel step ( 202 ) may be used to add the second catalyst KOH  108 A into a closed reaction vessel containing the used oil  127  for only 5 minutes ( 210 ). After 5 minutes the methanol  104  may be added ( 203 ) to used oil  127 B within 4 minutes ( 212 ). The system from here on may be totally closed to the atmosphere to prevent the loss of alcohol. The reaction mix may be kept just below the boiling point of the alcohol (around 146° F.) to speed up the reaction  150 . Recommended reaction time varies from 4-5 minutes and the temperature may be between 135° F.-138° F. This invention is sequential addition of catalyst and alcohol. Excess alcohol may be normally used to ensure total conversion of the fat or oil to its esters. 
         [0029]    In  FIG. 3 , another embodiment is disclosed. In step  2 , simultaneous addition of catalyst  108  A (KOH) ( 302 ) and alcohol methanol  104  ( 203 ) is added simultaneously for 15 minutes for reaction  310 . The transesterification reaction  150  produces biodiesel  121 B and glycerin  112 . The instant inventive step shows simultaneous addition of catalyst and alcohol. 
         [0030]    In conventional procedure biodiesel may be washed after the glycerin is removed to wash any particulates or material that might remain in the biodiesel. As shown in  FIGS. 1 ,  2  and  3  the resultant biodiesel  121 B is passed through a water spray  116 , which may be sprinkled using a water tube  114  through the column of biodiesel  121 B. This step ensures that remaining catalyst, and other contaminants are removed from biodiesel  121 B. The water  118  settles at the bottom of the chamber by gravity and is removed. However, still some water remains ( FIG. 1 ) and in the instant invention a novel method for removing the remaining water is implemented ( FIGS. 2 and 3 ). In the current invention an extra step is added to perform a unique removal of this water. Water once it remains in the biodiesel may create problems when used as fuel for machines. It is critical to remove the water after the washing step. Mechanical adhesion, electrostatic adhesion, chemical adhesion, dispersive adhesion and/or diffusive adhesion may also be used for achieving water separation. The biodiesel  121 B is passed through a column of fiber glass wool or a water absorbent material  230  to remove the remaining water. The biodiesel may be passed from bottom to top through perforated tubes through the water adherent/absorbent material. The water adherent/absorbent material  230  is held in place by two plates on top and bottom. As the biodiesel  121 B passes through the water adherent/absorbent material the water is absorbed or adhered to the material and the remaining biodiesel  121 C is collected on the top via a tube. The process of passing the biodiesel  121 B is repeated at least three times through three different columns and resultant biodiesel is collected for ASTM value estimation in step  209 . The columns may contain the same or different water adherent/absorbent materials for efficient removal of the water. ASTM value analysis  111  was performed for the resultant biodiesel  121 C. Accordingly, a test was also done using ASTM standards and flashpoint, cloud point, oxidation stability, acid number, cold soak test, total glycerin, triglycerides as triolein, diglyceride as diolein and monoglyceride as monoolein were estimated for certain examples as shown in Table 5 below. The resultant biodiesel  121 C ( FIGS. 2 and 3 ) is used as fuel  125  for vehicle  130 . 
         [0031]    Once the reaction is complete, two major products exist: glycerin  112  and biodiesel  121 . Each has a substantial amount of the excess methanol that was used in the reaction. The reacted mixture may sometimes be neutralized at this step if needed. The glycerin phase is much denser than biodiesel phase and the two can be gravity separated with glycerin simply drawn off the bottom of the settling vessel. In some cases, a centrifuge may be used to separate the two materials faster. 
         [0032]    The truncated transesterification time and calculation for amount of catalyst and alcohol is also one embodiment that differentiates the instant invention from the traditional method of making biodiesel. The resultant biodiesel has a very low ASTM number and the production time may be cut drastically to reduce cost and produce biodiesel efficiently. 
         [0033]    Once the glycerin and biodiesel phases have been separated, the excess alcohol in each phase may be removed with a flash evaporation process or by distillation before the water spray wash. In others systems, the alcohol may be removed and the mixture neutralized before the glycerin and esters have been separated. In either case, the alcohol may be recovered using distillation equipment and may be re-used. 
         [0034]    Several optimization processes and methods were done to arrive at optimum concentration of catalyst, alcohol, addition time, addition procedure, type of catalyst and the ratio of catalyst to the alcohol. The results of these methods and processes are shown in tables and discussed as follows. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Sequential addition of catalyst sodium methylate and alcohol methanol 
               
             
          
           
               
                 USED OIL 
                 METER total 
                 METHANOL 
                 CATALYST 
                 TIME 
                 GLYCERIN 
               
               
                 (GALLONS) 
                 gallons 
                 (GALLONS) 
                 (GALLONS) 
                 (MINS) 
                 VALUE 
               
               
                   
               
             
          
           
               
                 4300 
                 324 
                 324 
                 128 
                   
                   
               
               
                   
                 366 
                 42 
                 18 
               
               
                   
                 408 
                 42 
                 18 
               
               
                   
                 450 
                 42 
                 18 
                 5.30 hours 
                 0.84 
               
               
                   
               
             
          
         
       
     
         [0035]    900 gallons of Glycerin was removed from the above reaction. The resultant ASTM value was higher than the accepted value. The conclusion of the test was that sodium methylate and the methanol combination was at acceptable glycerin value to proceed to step  2 . Potassium hydroxide was tested for the next set of experiments for step  2  transesterification processes. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Process of mixing methanol in stages after a step of stopping. 
               
             
          
           
               
                   
                 OIL 
                 KOH 
                 TIME 
                 METHANOL 
                 TIME 
                 STOP 
                 GLYCERIN 
               
               
                 EXPT 1 
                 (Gallons) 
                 (Gallons) 
                 (mins) 
                 (Gallons) 
                 (mins) 
                 (mins) 
                 VALUE 
               
               
                   
               
             
          
           
               
                 STEP 1 
                 4000 
                 96 
                 5 
                 0 
                 4 
                 4 
                   
               
               
                 STEP 2 
                   
                   
                 5 
                 180 
                 2 
                 10 
                 0.11 
               
               
                   
               
             
          
         
       
     
         [0036]    Table 2 data shows the ASTM number to be well within the standards (acceptable value is 0.25). However, it is a two step process and is a bit unstable. This process may show that KOH and methanol are a good combination for the second half of the method of making biodiesel with acceptable ASTM values. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Ratio optimization of KOH and Methanol 
               
             
          
           
               
                   
                 KOH 
                 TIME 
                 METHANOL 
                 TIME 
                 ASTM 
               
               
                   
                 (GALLONS) 
                 (MINS) 
                 (GALLONS) 
                 (MINS) 
                 VALUE 
               
               
                   
               
             
          
           
               
                   
                 100 
                 5 
                 220 
                 4 
                 0.34 
               
               
                   
                 80 
                 5 
                 220 
                 4 
                 0.30 
               
               
                   
                 100 
                 5 
                 140 
                 4 
                 0.26 
               
               
                   
                 80 
                 5 
                 200 
                 4 
                 0.11 
               
               
                   
                 80 
                 5 
                 160 
                 4 
                 0.08 
               
               
                   
               
             
          
         
       
     
         [0037]    Table 3 shows that different combinations of KOH and methanol give different ASTM value. One part of KOH and two parts of methanol give the best results. This experiment also has spilt timings for adding the two components. The above experiments lead to calculation of optimal ratio of catalyst to alcohol. 
         [0038]    Several percentages such as 30%, 25%, 20%, 15% and 10% as factor were tested and transesterification were performed in small lab scale volumes. However 20% as a factor resulted in the best ASTM value for the biodiesel. The following formula was finally used for industrial scale production of biodiesel with a starting material of 4000 gallons of used oil in step  2  for calculating catalyst and alcohol: 
         [0000]      Glycerin value in gallons for the used oil×20% of the glycerin value in gallons=Catalyst (KOH) in gallons
 
         [0000]      Glycerin value in gallons=remove the decimal in front of glycerin value and convert it to gallons. 
         [0000]      Catalyst (KOH) in gallons+glycerin value in gallons=Alcohol (methanol) in gallons 
         [0039]    For example glycerin value=0.50. The minimum catalyst to be used would be 50 gallons. 50 gallons×20% of minimum gallons to be used=60 Gallons of Potassium Hydroxide 60 Gallons of Potassium Hydroxide+50 Gallons (glycerin value in gallons)=110 gallons of alcohol (methanol). 
         [0040]    The factor may vary depending on the used oil quality and may range from 50-100% for calculations. 
         [0041]    In order to achieve a single step experiment further studies were performed by adding the two components at the same time. Table 4 below shows some results. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Single step addition of KOH and Methanol to achieve optimal results 
               
             
          
           
               
                   
                 OIL 
                 KOH 
                 METHANOL 
                 TIME 
                 ASTM 
               
               
                   
                 (GALLONS) 
                 (GALLONS) 
                 (GALLONS) 
                 (MINS) 
                 VALUE 
               
               
                   
                   
               
             
          
           
               
                 EXPT 1 
                 4200 
                 80 
                 220 
                 5 
                 0.10 
               
               
                 EXPT 2 
                 4200 
                 80 
                 220 
                 15 
                 0.07 
               
               
                   
               
             
          
         
       
     
         [0042]    Table 4 data shows that the KOH and methanol can be added simultaneously and the time can be further reduced to get good ASTM value for resultant biodiesel. 
         [0043]    ASTM analysis was performed for a batch of used oil 4600 gallons. The following experiment was performed and the starting used oil was 4600 gallons. In the first transesterification step  565  gallons of methanol and 186 gallons of sodium methylate. The glycerin value was 0.78. The second step of transesterification was performed using 80 gallons of potassium hydroxide and 220 gallons of methanol for 15 minutes. The resultant biodiesel was washed with water. The water was removed by passing it through a chamber containing fiber glass wool. The biodiesel was passed through three such chambers and finally clean biodiesel was collected and ASTM values and glycerin value was determined. The resultant glycerin value was 0.07. The resultant clean biodiesel may be used as fuel for automotives. Two step transesterification was performed as shown in  FIG. 3  and the ASTM results are shown below in Table 5. 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 ASTM numbers for an Experiment: 
               
             
          
           
               
                   
                 LEVEL FOUND 
                 DETECTION 
                   
               
               
                 ANALYSIS 
                 (UNITS) 
                 LIMITS 
                 METHOD 
               
               
                   
               
             
          
           
               
                 Flashpoint 
                 &gt;150° C. 
                 4 
                 ASTM D93 
               
               
                 Could point 
                 2.0° C. 
                   
                 ASTM D2500 
               
               
                 Oxidation Stability 
                 10.0 hours 
                 0.1 
                 EN14112 
               
               
                 Acid Number 
                 0.18 mg KOH/g 
                 0.05 
                 ASTM D664 
               
               
                 Cold Soak Test 
                 103 sec 
                 20 
                 ASTM D 7501-09 
               
               
                 Total Glycerin 
                 0.138% mass 
                 0.001 
                 ASTM D6584 
               
               
                 Free Glycerin 
                 n.d % mass 
                 0.001 
                 ASTM D6584 
               
               
                 Triglycerides as 
                 0.008% 
                 0.001 
                 ASTM D6584 
               
               
                 Triolein 
                   
                   
                   
               
               
                 Diglyceride as 
                 0.023% 
                 0.001 
                 ASTM D6584 
               
               
                 Diolein 
                   
                   
                   
               
               
                 Monoglyceride as 
                 0.106% 
                 0.001 
                 ASTM D6584 
               
               
                 Monoolein 
                   
                   
                   
               
               
                   
               
             
          
         
       
     
         [0044]    The resultant product produced by the method and the process used as shown in  FIGS. 2 and 3  show very good ASTM values and is well below required standards. 
         [0045]    In addition, it will be appreciated that the various examples and methods disclosed herein may be embodied using many different equipments and steps. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.