Blending of summer gasoline containing ethanol

Provided is a method for blending an unleaded summer gasoline containing ethanol. The method comprises providing a substantially oxygenate free unleaded gasoline blend stock having an RVP of no greater than 7.0, and preferably no greater than 6.0, and then adding sufficient ethanol to the gasoline blend stock such that the ethanol addition does not cause the T50 value to drop below the ASTM D 4814 minimum requirements of 170.degree. F.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to fuels, particularly gasoline fuels which
 contain ethanol. More specifically, the present invention relates to a
 method of making a summer, low-emission gasoline fuel which contains
 ethanol and complies with the California Code of Regulations.
 2. Brief Description of the Related Art
 One of the major environmental problems confronting the United States and
 other countries is atmospheric pollution caused by the emission of
 pollutants in the exhaust gases and gasoline vapor emissions from gasoline
 fueled automobiles. This problem is especially acute in major metropolitan
 areas where atmospheric conditions and the great number of automobiles
 result in aggravated conditions. While vehicle emissions have been reduced
 substantially, air quality still needs improvement. The result has been
 that regulations have been passed to further reduce such emissions by
 controlling the composition of gasoline fuels. These specially formulated,
 low emission gasolines are often referred to as reformulated gasolines.
 California's very strict low emissions gasoline is often referred to as
 California Phase 2 or Phase 3 gasoline. In these gasolines,
 oxygen-containing hydrocarbons, or oxygenates, are often blended into the
 fuel.
 Congress and regulatory authorities, such as CARB (the California Air
 Resources Board), have focused on setting specifications for low
 emissions, reformulated gasoline. The specifications, however, require the
 presence of oxygenates in gasoline sold in areas that are not in
 compliance with federal ambient air quality standards for ozone, and the
 degree of non-attainment is classified as severe, or extreme. Among the
 emissions which the reformulated gasoline is designed to reduce, are
 nitrogen oxides (NO.sub.x), hydrocarbons (HC), and toxics (benzene,
 1,3-butadiene, formaldehyde and acetaldehyde). A reduction in these
 emissions has been targeted due to their obvious impact upon the air we
 breathe and the environment in general.
 Oxygenated gasoline is a mixture of conventional hydrocarbon-based gasoline
 and one or more oxygenates. Oxygenates are combustible liquids which are
 made up of carbon, hydrogen and oxygen. All the current oxygenates used in
 reformulated gasolines belong to one of two classes of organic molecules:
 alcohols and ethers. The Environmental Protection Agency regulates which
 oxygenates can be added to gasoline and in what amounts.
 The primary oxygen-containing compounds employed in gasoline fuels today
 are methyl tertiary butyl ether (MTBE) and ethanol. While oxygen is in
 most cases required in reformulated gasolines to help effect low
 emissions, the presence of ethers such as MTBE in gasoline fuels has
 particularly begun to raise environmental concerns. For example, MTBE has
 been observed in drinking water reservoirs, and in a few instances, ground
 water in certain areas of California. As a result, the public is beginning
 to question the benefits and/or importance of having an ether such as MTBE
 in cleaner burning gasolines, if the ether simply pollutes the environment
 in other ways.
 Thus, while some of the concerns with regard to gasoline fuels containing
 ethers, could be overcome by further safe handling procedures and the
 operation of present facilities to reduce the risk of any spills and
 leaks, there remains a growing public concern with regard to the use of
 ethers such as MTBE in gasoline fuels. In an effort to balance the need
 for lower emission gasolines and concerns about the use of ethers it,
 therefore, would be of great benefit to the industry if a cleaner burning
 gasoline without ethers, which complied with the requirements of the
 regulatory authorities (such as CARB), could be efficiently made.
 Replacing ethers such as MTBE with ethanol is one possibility to reducing
 the use of MTBE. However, the use of ethanol presents other problems,
 particularly in its handling and transportation. Transporting a gasoline
 containing ethanol from a refinery to a terminal, particularly through a
 pipeline, often results in the ethanol picking up water. This results in
 the final gasoline not meeting the specifications required, e.g., by the
 California Code of Regulations. As well, rust in the pipeline can be
 loosened by the ethanol, resulting in further contamination of the
 gasoline.
 The replacement of ethers with ethanol in the blending of gasolines which
 meet the California Code of Regulations, therefore, still requires the
 need to resolve several major problems. Because of the importance ethanol
 is beginning to play in oxygenated gasoline, a resolution of these
 problems would be of great interest to the industry.
 It is therefore an object of the present invention to provide a method of
 blending ethanol into a gasoline formulation while overcoming the
 foregoing problems.
 It is yet another object of the present invention to provide a novel method
 for obtaining a gasoline formulation containing ethanol which meets the
 California Code of Regulations.
 Yet another object of the present is to provide a method of blending a
 gasoline formulation containing ethanol at a site remote from the
 refinery, which formulation meets the California Code of Regulations.
 These and other objects of the present invention will become apparent upon
 a review of the following description, the Figures of the Drawing, and the
 claims appended hereto.
 SUMMARY OF THE INVENTION
 In accordance with the foregoing objectives, there is provided by the
 present invention a method for blending unleaded gasoline containing
 ethanol, and having A Reid Vapor Pressure (RVP) in pounds per square inch
 (psi) of 8.0 or less, and more preferably 7.0 or less. The method
 comprises providing a substantially oxygenate free unleaded gasoline blend
 stock which has an RVP of no greater than 7.0, and more preferably no
 greater than 6.0. Ethanol is then added to the gasoline blend stock in an
 amount such that the final gasoline meets the California Code of
 Regulations, with the unleaded gasoline blend stock to which the ethanol
 is added having a T50 sufficiently high such that the ethanol addition
 does not cause the T50 value to drop below the ASTM D 4814 minimum
 requirement of 170.degree. F. In a preferred embodiment, the amount of
 ethanol added is at least 2.0 volume percent based on the final gasoline.
 Among other factors, the present invention is based upon the discovery that
 the addition of ethanol to a gasoline blend stock cannot be a linear
 addition, for the specifications of the gasoline are changed non-linearly
 when ethanol is added. The specifications of the gasoline blend stock must
 therefore be controlled in order to compensate for the addition of
 ethanol. This is particularly true for the RVP and T50 characteristics of
 the gasoline. The present invention, therefore, blends ethanol with a
 gasoline blend stock which has an RVP sufficiency low and a T50
 specification sufficiently high such that the addition of the desired
 amount of ethanol results in a gasoline which is in compliance with the
 California Code of Regulations. It is the discovery of the need to so
 control the RVP and T50 specifications of the gasoline blend stock which
 permits one to successfully blend the ethanol into a compliant gasoline
 formulation.
 In a preferred embodiment, the present invention allows one to blend a
 gasoline blend stock having predetermined RVP and T50 specifications at a
 refinery which does not contain ethanol, transport the blend stock through
 a pipeline to a terminal, and mix the ethanol and blend stock at the
 terminal with confidence that the final gasoline composition meets the
 California Code of Regulations. This method allows one to avoid the
 problems inherent in the transporting of an ethanol containing gasoline
 formulation, while meeting all required specifications for the gasoline.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
 Gasolines are well known fuels, generally composed of a mixture of numerous
 hydrocarbons having different boiling points at atmospheric pressure.
 Thus, a gasoline fuel boils or distills over a range of temperatures,
 unlike a pure compound. In general, a gasoline fuel will distill over the
 range of from about, room temperature to 437.degree. F. (225.degree. C.).
 This temperature range is approximate, of course, and the exact range will
 depend on the conditions that exist in the location where the automobile
 is driven. The distillation profile of the gasoline can also be altered by
 changing the mixture in order to focus on certain aspects of gasoline
 performance, depending on the time of year and geographic location in
 which the gasoline will be used.
 Gasolines are therefore, typically composed of a hydrocarbon mixture
 containing aromatics, olefins, naphthenes and paraffins, with reformulated
 gasoline most often containing an oxygen compound. The fuels contemplated
 in the present invention are substantially ether free unleaded gasolines
 (herein defined as containing a concentration of lead no greater than 0.05
 gram of lead per gallon which is 0.013 gram of lead per liter), which
 contain ethanol as the oxygen compound. The anti-knock value (R+M)/2 for
 regular gasoline is generally at least 87, at least 89 for mid-range, and
 for premium at least 91, and generally at least 92.
 In an attempt to reduce harmful emissions upon the combustion of gasoline
 fuels, regulatory boards as well as Congress have developed certain
 specifications for reformulated gasolines. One such regulatory board is
 that of the State of California, i.e., the California Air Resources Board
 (CARB). In 1991, specifications were developed by CARB for California
 gasolines which, based upon testing, should provide good performance and
 low emissions. The specifications and properties of the reformulated
 gasoline, which is referred to as the Phase 2 reformulated gasoline or
 California Phase 2 gasoline, are shown in Table 1 below.
 TABLE 1
 Properties and Specifications
 for Phase 2 Reformulated Gasoline
 Averaging
 Fuel Property Units Flat Limit Limit Cap Limit
 Reid vapor pressure psi, max. 7.00.sup.1 7.00.sup.1
 (RVP)
 Sulfur (SUL) ppmw 40 30 80
 Benzene (BENZ) vol. %, max. 1.00 0.80 1.20
 Aromatic HC (AROM) vol. %, max. 25.0 22.0 30.0
 Olefin (OLEF) vol. %, max. 6.0 4.0 10.0
 Oxygen (OXY) wt. % 1.8 (min) 0 (min)
 2.2 (max) 3.5 (max)
 Temperature at 50% deg. F. 210 200 220
 distilled (T50)
 Temperature at 90% deg. F. 300 290 330
 distilled (T90)
 .sup.1 Applicable during the summer months identified in 13 CCR, sections
 2262.1 (a) and (b); California requires adherence to ASTM specifications.
 Recently, Phase 3 regulations have been developed. At present, the gasoline
 can meet either Phase 2 or Phase 3 regulations, but beginning Jan. 1,
 2003, Phase 3 regulations must be met. The specifications and properties
 of the reformulated California Phase 3 gasoline are shown in Table 2
 below:
 TABLE 2
 Properties and Specifications for Phase 3 Reformulated Gasoline
 Fuel Property Units Flat Limit Average Limit Cap Limit
 Reid vapor psi, max. 7.00 6.40-7.20.sup.1
 pressure (RVP)
 Sulfur (SUL) ppmw 20 15 60.sup.2 /30.sup.3
 Benzene vol. %, max 0.80 0.70 1.10
 (BENZ)
 Aromatic HC vol. %, max 25.0 22.0 35.0
 (AROM)
 Olefin (OLEF) vol. %, max 6.0 4.0 10.0
 Oxygen (OXY) wt. % 1.8 (min) 3.7.sup.4
 2.2 (max)
 Temperature at deg. F. 213 203 220
 50% distilled
 (T50)
 Temperature at deg. F. 305 295 330
 90% distilled
 (T90)
 .sup.1 Applicable during the summer months identified in 13 CCR, Sections
 2262, 1(a) and (b); California requires adherence to ASTM specifications.
 .sup.2 1/1/2003-12/31/2004.
 .sup.3 Beginning 1/1/2005.
 .sup.4 For ethanol only.
 In Tables 1 and 2, as well as for the rest of the specification, the
 following definitions apply:
 Aromatic hydrocarbon content (Aromatic HC, AROM) means the amount of
 aromatic hydrocarbons in the fuel expressed to the nearest tenth of a
 percent by volume in accordance with 13 CCR (California Code of
 Regulations), section 2263.
 Benzene content (BENZ) means the amount of benzene contained in the fuel
 expressed to the nearest hundredth of a percent by volume in accordance
 with 13 CCR, section 2263.
 Olefin content (OLEF) means the amount of olefins in the fuel expressed to
 the nearest tenth of a percent by volume in accordance with 13 CCR,
 section 2263.
 Oxygen content (OXY) means the amount of actual oxygen contained in the
 fuel expressed to the nearest tenth of a percent by weight in accordance
 with 13 CCR, section 2263.
 Potency-weighted toxics (PWT) means the mass exhaust emissions of benzene,
 1,3-butadiene, formaldehyde, and acetaldehyde, each multiplied by their
 relative potencies with respect to 1,3-butadiene, which has a value of 1.
 Predictive model means a set of equations that relate emissions performance
 based on the properties of a particular gasoline formulation to the
 emissions performance of an appropriate baseline fuel.
 Reid vapor pressure (RVP) means the vapor pressure of the fuel expressed to
 the nearest hundredth of a pound per square inch in accordance with 13
 CCR, section 2263.
 Sulfur content (SUL) means the amount by weight of sulfur contained in the
 fuel expressed to the nearest part per million in accordance with 13 CCR,
 section 2263.
 50% distillation temperature (T50) means the temperature at which 50% of
 the fuel evaporates expressed to the nearest degree Fahrenheit in
 accordance with 13 CCR, section 2263.
 90% distillation temperature (T90) means the temperature at which 90% of
 the fuel evaporates expressed to the nearest degree Fahrenheit in
 accordance with 13 CCR, section 2263.
 Toxic air contaminants means exhaust emissions of benzene, 1,3-butadiene,
 formaldehyde, and acetaldehyde.
 The pollutants addressed by the foregoing specifications include oxides of
 nitrogen (NO.sub.x), and hydrocarbons (HC), which are generally measured
 in units of g/mile, and potency-weighted toxics (PWT), which are generally
 measured in units of mg/mile.
 The California Phase 2 and Phase 3 reformulated gasoline regulations define
 a comprehensive set of specifications for a gasoline (Tables 1 and 2).
 These specifications have been designed to achieve large reductions in
 emissions of criteria and toxic air contaminants from gasoline-fueled
 vehicles. Gasolines which do not meet the specifications are believed to
 be inferior with regard to the emissions which result from their use in
 vehicles. All gasolines sold in California, beginning Jun. 1, 1996, have
 had to meet CARB's Phase 2 requirements as described below, and beginning
 Jan. 1, 1993, Phase 3 regulations must be met. The specifications address
 the following eight gasoline properties:
 Reid vapor pressure (RVP)
 Sulfur
 Oxygen
 Aromatic hydrocarbons
 Benzene
 Olefins
 Temperature at which 90 percent of the fuel has evaporated (T90)
 Temperature at which 50 percent of the fuel has evaporated (T50)
 The Phase 2 and Phase 3 gasoline regulations include gasoline
 specifications that must be met at the time the gasoline is supplied from
 the production facility. Producers have the option of meeting either
 "flat" limits or, if available, "averaging" limits, or, alternatively a
 Predictive Model equivalent performance standard using either the "flat"
 or "averaging" approach.
 The flat limits must not be exceeded in any gallon of gasoline leaving the
 production facility when using gallon compliance. For example, the
 aromatic content of gasoline, subject to the default flat limit, could not
 exceed 25.0 volume percent (see Tables 1 and 2).
 The averaging limits for each fuel property established in the regulations
 are numerically more stringent than the comparable flat limits for that
 property. Under the averaging option, the producer may assign differing
 "designated alternative limits" (DALs) to different batches of gasoline
 being supplied from the production facility. Each batch of gasoline must
 meet the DAL assigned for the batch. In addition, a producer supplying a
 batch of gasoline with a DAL less stringent than the averaging limit must,
 within 90 days before or after, supply from the same facility sufficient
 quantities of gasoline subject to more stringent DALs to fully offset the
 exceedances of the averaging limit. Therefore, an individual batch may not
 meet the California Phase 2 or Phase 3 Predictive Model when using
 averaging, but in aggregate, over time, they must.
 The Phase 2 and Phase 3 gasoline regulations also contain "cap" limits. The
 cap limits are absolute limits that cannot be exceeded in any gallon of
 gasoline sold or supplied throughout the gasoline distribution system.
 These cap limits are of particular importance when the California
 Predictive Model or averaging is used.
 A mathematical model, the California Predictive Model, has also been
 developed by CARB to allow refiners more flexibility. Use of the
 predictive model is designed to allow producers to comply with the Phase 2
 or Phase 3 gasoline requirements by producing gasoline to specifications
 different from either the averaging or flat limit specifications set forth
 in the regulations. However, producers must demonstrate that the
 alternative Phase 2 or Phase 3 gasoline specifications will result in
 equivalent or lower emissions compared to Phase 2 or Phase 3 gasoline
 meeting either the flat or averaging limits as indicated by the Predictive
 Model. Further, the cap limits must be met for all gasoline formulations,
 even alternative formulations allowed under the California Predictive
 Model. When the Predictive Model is used, the eight parameters of Tables 1
 and 2 are limited to the cap limits.
 In general, the California Predictive Model is a set of mathematical
 equations that allows one to compare the expected exhaust emissions
 performance of a gasoline with a particular set of fuel properties to the
 expected exhaust emissions performance of an appropriate gasoline fuel.
 One or more selected fuel properties can be changed when making this
 comparison.
 Generally, in a predictive model, separate mathematical equations apply to
 different indicators. For example, a mathematical equation could be
 developed for an air pollutant such as hydrocarbons; or, a mathematical
 equation could be developed for a different air pollutant such as the
 oxides of nitrogen.
 Generally, a predictive model for vehicle emissions is typically
 characterized by:
 the number of mathematical equations developed,
 the number and type of motor vehicle emissions tests used in the
 development of the mathematical equations, and
 the mathematical or statistical approach used to analyze the results of the
 emissions tests.
 The California Predictive Model is comprised of eighteen (18) mathematical
 equations. One set of six equations predicts emissions from vehicles in
 Technology Class 3 (model years 1981-1985), another set of six is for
 Technology Class 4 (model years 1986-1995), and another set for Technology
 Class 5 (model years 1996-2005). For each technology class, one equation
 estimates the relative amount of exhaust emissions of hydrocarbons, the
 second estimates the relative amount of exhaust emissions of oxides of
 nitrogen, and four are used to estimate the relative amounts of exhaust
 emissions of the four toxic air contaminants: benzene, 1,3-butadiene,
 acetaldehyde, and formaldehyde. These toxic air contaminants are combined
 based on their relative potential to cause cancer, which is referred to as
 potency-weighting.
 In creating the California Predictive Model, CARB compiled and analyzed the
 results of over 7,300 vehicle exhaust emissions tests. A standard
 statistical approach to develop the mathematical equations to estimate
 changes in exhaust emissions was used based upon the data collected. It is
 appreciated that the California Predictive Model might change with regard
 to certain of the components considered, and their limits. In fact, at
 present, as discussed above, there exists a California Phase 2 and a
 California Phase 3 Predictive Model. However, it is believed that the
 present invention and its discovery that a blending process can be used to
 effectively create the gasolines of the present invention, can be used to
 blend a gasoline in compliance with the specifications of any California
 Predictive Model.
 In summary, specific requirements were created by the California Air
 Resources Board to restrict the formulation of gasoline to ensure the
 production of gasoline which produces low emissions when used in
 automobiles.
 The present invention provides one with a method of blending a low
 emission, ether free gasoline economically and in a commercially plausible
 manner, which gasoline has an RVP suitable for the summer season. The
 gasoline obtained is in compliance with the California Code of Regulations
 for reformulated gasoline and the California Predictive Model, at present,
 either the Phase 2 or Phase 3 Predictive Model, and it contains
 substantially no ethers. The gasoline is also in compliance with ASTM D
 4814.
 By substantially free of ethers, for the present invention, is meant that
 there is less than 0.1 wt. %, more preferably less than 0.05 wt. %, and
 most preferably less than 0.01 wt. % of oxygen attributed to ether
 compounds in the blended gasoline. The gasoline does contain ethanol as a
 substantial replacement for the ether such as MTBE.
 The gasoline of the present invention is also most preferably low in sulfur
 content, with the sulfur content being about 30 ppm wt. or less. It is
 preferred that the sulfur content is less than 20 ppm, more preferably
 less than 15 ppm wt., even more preferably less than 10 ppm wt., more
 preferably less than 5 ppm wt., and most preferably less than 1 ppm wt.
 The amount of sulfur can be controlled by specifically choosing streams
 which are low in sulfur for blending in the gasoline. It has been found
 that the use of low sulfur permits one to more easily and economically
 blend a gasoline with low emissions. Thus, the low sulfur content is a
 preferred aspect of the present invention.
 The final gasoline compositions of the present invention also preferably
 have a T50 of less than 210.degree. F., or preferably less than
 200.degree. F., and most preferably about 185.degree. F. or less, when
 Phase 2 gasoline is being blended, preferably less than 203.degree. F.,
 more preferably less than 200.degree. F., and most preferably less than
 190.degree. F. if Phase 3 gasoline is being blended. The olefin content is
 also less than 8 vol. %, more preferably less than 6 vol. %, and most
 preferably less than 3 vol. %. The amount of benzene is also less than 0.7
 vol. % and less than 0.5 vol. % in the most preferred embodiment.
 As the gasoline of the present invention is designed for the summer months,
 the RVP is generally lower. The RVP is generally about 8.0 or less, and
 more preferably about 7.2 or 7.0 or less.
 The gasoline of the present invention can also be blended to achieve any
 octane rating (R+M)/2 desired. A regular gasoline with an octane rating of
 at least 87, a mid-grade gasoline with an octane rating of at least 89 or
 90, or a premium gasoline with an octane rating of at least 91 can all be
 prepared in accordance with the present invention.
 The method of the present invention comprises continuously blending
 gasoline component streams from a refinery process plant to prepare a
 gasoline blend stock. The blend stock will generally have an RVP value no
 greater than 5.5 to 7.0 psi, more preferably in the range of from about
 5.5 to 6.5, and most preferably an RVP of about 6.0 or less, e.g., in the
 range of from about 5.5 to 6.0; and, a T50 value sufficiently high such
 that the addition of ethanol does not cause the T50 value to drop below
 the ASTM D 4814 minimum requirement of 170.degree. F. Generally the T50
 value for the blend stock is at least 190.degree. F. Any of the
 conventional gasoline component streams which are blended into gasolines
 can be used.
 A preferred blend stock gasoline composition of the present invention has
 an RVP of less than 6.0 psi, a T50 value of greater than 190.degree. F.,
 and a sulfur content of no greater than 30 ppm wt. sulfur, more preferably
 less than 20 ppm wt. sulfur, and most preferably less than 10 ppm wt.
 sulfur. The amount of ethanol that is blended with such a blend stock is
 preferably in the range of from 2.0 to 6.0 vol. %.
 The specific amount of ethanol that can be blended with a particular blend
 stock can be determined by creating a model from a number of runs as shown
 in the examples. Once such a model is created, the desired amount of
 ethanol can be determined and blended according to the model in order to
 meet the RVP and T50 California Code requirements in accordance with the
 model.
 A schematic of a suitable system for blending the gasoline blend stock is
 shown in FIG. 1 of the Drawing. The gasoline component streams are
 provided at 1, and flow through component pump and flow meters 2.
 Component control valves 3 control how much of each stream is let into the
 blending process 4, to create the blended gasoline. The blended gasoline
 is then generally stored in a gasoline product tank 5.
 To begin the process, a blending model can be used to approximate the
 blending of the gasoline feed stock. Such blending models can be created
 via experience of blending gasoline feed stocks together with ethanol.
 Such experience can be gained from the examples which follow.
 It is generally important to include an analysis of the blended gasoline
 feed stock. Such testing can be periodic or continuous. In general, it is
 preferred to use an on-line analyzer as shown at 6. Generally, the
 analysis run involves the entire boiling range of the gasoline, including
 T50 and T90, the RVP of the blended gasoline, the benzene/aromatics
 content and the sulfur content. The tests run can be as follows:
 For distillation, the analyzer utilizes an Applied Automation Simulated
 Distillation Motor Gasoline Gas Chromatograph. This analyzer is similar to
 the instrument described in ASTM D 3710-95: Boiling Range Distribution of
 Gasoline by Gas Chromatography. This test method is designed to measure
 the entire boiling range of gasoline, either high or low Reid Vapor
 Pressures, and has been validated for gasolines containing the oxygenates
 methyl tertiary butyl ether (MTBE) and tertiary amul methyl either (TAME).
 Alternatively, the ASTM D 86 distillation method can be used, although not
 preferred for an on-line analyzer. Either test can be run.
 Measuring RVP utilizes an ABB Model 4100 Reid Vapor Pressure Analyzer. This
 analyzer is described in ASTM D 5482-96. This is a substitute for the
 "CARB RVP" calculation based on the Dry-Vapor Pressure result from D 5191,
 which is itself a substitute for ASTM method 393-89. Either can be used.
 The method for measuring benzene and aromatic content can utilize the
 Applied Automation Standard Test Method for Determination of Benzene,
 Toluene, C8 and Heavier Aromatics, and Total Aromatics in Finished Motor
 Gasoline Gas Chromatograph. The analyzer is similar to the instrument
 described in ASTM D 5580-95: Standard Tests Method for Determination of
 Benzene, Toluene, Ethylbezene, p/m-Xylene, C9 and Heavier Aromatics, and
 Total Aromatics in Finished Gasoline by Gas Chromatography. This is a
 substitute for ASTM D 5580 and ASTM D 1319 (for aromatics) and ASTM D 3606
 (for benzene) methods which methods can also be used.
 Olefin content can be measured using any suitable method. ASTM D 1319 is
 presently preferred. Other methods can also be used.
 For measurement of sulfur content, the analyzer can utilize an ABB Model
 3100 Sulfur in Gasoline Gas Chromatograph. The method is designed to
 quantify the amount of sulfur in a hydrocarbon steam as a substitute for
 the ASTM D 2622 or D 5453-93 method, which can also be used.
 The information from the analysis is then fed to a computer 7 which can
 control the component flows to produce a gasoline blend which complies
 with a California Predictive Model for the summer season. The information
 provided to the computer can comprise information from on-line analysis,
 as well as information from an analysis conducted in a laboratory 8. If
 desired, tank information and blend specifications for the gasoline in the
 product tank can also be provided to the computer. Samples can be drawn
 from the gasoline product tank, for example, at 9, for laboratory testing.
 Once the feed stock is blended, it can be mixed directly with the desired
 amount of ethanol for which the feed stock has been blended, or simply
 transported, e.g., through a pipeline, to a terminal. Mixing of the
 ethanol with the feed stock can then be accomplished at the terminal in
 accordance with the present invention.
 EXAMPLES
 Several blended gasoline feed stocks were made to create a model. The
 various component streams used were conventional gasoline component
 streams including:
 (i) whole alkylate;
 (ii) FCC gasoline;
 (iii) hydrobate;
 (iv) pentane/hexane isomerate;
 (v) heavy reformate;
 (vi) hydrotreated FCCL; and
 (vii) alkylate.
 In a blending system, all of the foregoing component streams are preferably
 provided from the same refinery. However, any one of the streams used can
 be provided from an outside source, but it is preferred for the present
 invention that the component streams originate as streams in the refinery
 on site. For the present examples, small samples were used on a laboratory
 scale in order to create a model.
 The characteristics of such various component streams are provided in Table
 2 below. The relative amounts of each component in each blended feed stock
 for the examples is also provided in Table 3.
 Once each of the blend stocks were made, it was mixed with 2% by volume,
 4%, 6% and 10% ethanol. The resulting final gasoline specifications were
 then measured and are reported in Table 4 below. The results are
 graphically presented in FIGS. 2-13. Table 4 and the graphs of FIGS. 2-13
 can be used as a model in determining an appropriate amount of ethanol to
 be blended with a particular blend stock.
 While the invention has been described with preferred embodiments, it is to
 be understood that variations and modifications may be resorted to as will
 be apparent to those skilled in the art. Such variations and modifications
 are to be considered within the purview and the scope of the claims
 appended hereto.