The Change of a Petroleum ERA

Posted on July 30, 2014 by Brody Jack Miller

With the outbreak of World War II, the petroleum refinery processes had to accommodation for the increasing need for high octane gasoline to fuel the war effort. The petroleum industry turned to catalytic refining to supply the fuel to run the more powerful spark ignition engines. The catalytic processes quickly evolved from the McAfee Batch reactor in 1915, to the Houdry fixed-bed reactor in 1936, to the TCC moving-bed reactor, and finally the FCC fluidized-bed reactor up until the 1970s. Since the main goal of petroleum refinery was to produce gasoline for the war the technologies were rapidly changing to make as much high octane gasoline product as possible. As a result the refining infrastructure was changed forever.

At the end of World War II, in 1945, many of the US refineries were producing high octane gasoline and allowed for the domestic automobile infrastructure to change accommodating for more powerful engines. [1] This would explain the birth of the muscle car era in 1965 through 1973 where mid-sized cars were equipped with large V8 high performance gas guzzling engines. [2] Along with the muscle car, the age of tetra ethyl lead high octane gasoline came to an end after the gas price increases from embargo crisis, the EPA’s Clean Air Act (1970) employing more strict emission regulations, and the growing popularity of catalytic isomerization. [1,3] Catalytic isomerization, which was initially used to produce aviation fuel in WWII, but was now being used to convert low octane n-paraffins into branched i-paraffins via a vapor phase platinum-bearing alumina-chloride catalyst. This marked the end of the Century Refinery. [1] During this refinery era multiple process were introduced including catalytic cracking, catalytic reforming, alkylation, catalytic polymerization, delayed coking, deasphalting, visbreaking, and hydrotreating. With the increasing need to become energy independent and more energy efficient, the petroleum refinery changed again to utilize the heavy ends for cleaner fuels utilizing the processes developed during catalytic refining. Today, the fuel of the future is still unknown but one thing is for certain, if it wasn’t for the “gasoline boom” in World War II there would be no way of telling where the refining industry would be today.

Sources:
1. Self, F., Ekholm, E., & Bowers, K. (). The Age Of The Catalytic Refinery 1940-1970. Refining Overview- Part 2 Development of the Modern Refinery (). : .
2. The Muscle Car Era and Gas Guzzling Automobiles. (n.d.). HubPages. Retrieved July 30, 2014, from http://tylerdurden1.hubpages.com/hub/Tthe-end-of-the-muscle-car-era-did-not-end-gas-guzzling-automobiles
3. Air Pollution and the Clean Air Act. (n.d.). EPA. Retrieved July 30, 2014, from http://www.epa.gov/air/caa/

Effects of Wastewater Treatment Processes in a Municipal Plant

Posted on July 27, 2014 by Brody Jack Miller

The reason refinery wastewater cannot not be treated in a municipal wastewater treatment plant is because of the levels of contaminates that exist in these stream. These contaminates include hydrocarbons, suspended solids, Mercaptans, Phenols, dissolved gases, and acids. In general the entire wastewater treatment process is a very delicate balance of processes. After taking a tour at Penn State’s Wastewater Treatment Plant I was amazing to learn how much attention was taken to ensure that the BOD levels and contaminate levels were suitable for proper digestion from their microorganisms, or as they referred to them as, “their bugs”. This balance was so delicate that the operators had to take samples, multiple times a day, from the wastewater stream to ensure a proper balance. Overall, if the refinery wastewater streams were sent to a municipal wastewater treatment plant it would need to be heavily treated before the actual treatment of the waste stream. According to Penn State’s wastewater treatment facility, the wastewater is treated to remove solids, BOD and other nutrients that cause excessive vegetative growth. [1] The increase of pretreatment may be too much for the plant to handle and would cause the system balance to be thrown off which may harm the microorganisms. All in all, a municipal wastewater treatment plant is an ecosystem of its own. By increasing the levels of nitrogen oxides, sulfur oxides and hydrocarbons, the wastewater ecosystem could be destroyed potentially throwing off the entire treatment process.

Sources:
1. Wastewater Services FAQ. (n.d.). — Office of Physical Plant. Retrieved July 25, 2014, from http://www.opp.psu.edu/about-opp/divisions/ee/util/documents/wastewater-services-faq

Catalytic Reforming is being limited by the EPA

Posted on July 13, 2014 by Brody Jack Miller

The catalytic reforming process has been in existence since 1952 and had a purpose to convert low-quality naphtha, usually heavy crudes, into high octane reformate. Catalytic reforming may be one of the most popular and frequently used reforming processes but in reality there are many other processes including platforming, powerforming, ultraforming, magnaforming, reforming, and rheniforming. [1] The catalytic reforming process utilizes chemical reactions such as dehydrenation, dehydroisomerization, dehydrocyclization, and isomerication to convert the naphthenic type crude into an aromatic or branched isomer chemical compound. Once the continuous, cyclic, semiregenerative chemical process takes place, the products formed are light naphtha, hydrogen gas, and high octane reformate. Even though the main objective was to form the high octane reformate for high octane gasoline production, which grew into high demand since the introduction of high compression internal combustion engine, the byproduct of hydrogen gas has much more value. The pure hydrogen gas can be used in many other processes such as hydrotreating and hydrocracking. Another high priority of the hydrogen gas is to lower the formation of coke on the catalysts which extends the catalyst’s lifespan and lowers frequency of replacement. In order to lower coke formation, hydrogen will need to be recycled at high rates and pressures. [1]

Even though there are many benefits from catalytic reforming and it encompasses roughly 30 to 40% of the United States’ gasoline requirements, the process it is slowly being limited due to its formation of aromatic compounds. The EPA and California Air Resources Board (CARB) see these benzene aromatics as greenhouse gas pollutants and are restricting the blending of reformate into high octane gasoline. [1] The EPA and president Obama have created the Renewable Fuel Standard (RFS) regulations in order to achieve the reduction of greenhouse gas emissions, reduce the importation of petroleum fuels, and ultimately encourage the use of renewable fuels. The overall goal was to protect future generations from health issues and the threat of global warming. [2] Every time someone fills up at the pump, a form of this law can be observed from the sticker on the pump that illustrates the percentage of ethanol used in the gasoline blend.
Resources:
1. Gary, J. H., & Handwerk, G. E. (2007). Petroleum refining: technology and economics. New York: M. Dekker.
2. Regulations & Standards | Transportation and Climate. (n.d.). EPA. Retrieved July 13, 2014, from http://www.epa.gov/otaq/climate/regulations.htm

Catalytic and Hydrocracking Processes

Posted on July 6, 2014 by Brody Jack Miller

Petroleum refining has drastically changed throughout history based off of advances in distillation technologies and demand for specific types of fuels. Today, petroleum refinery processes consist of mainly Catalytic Cracking (introduced in 1937) and Hydrocracking (introduced in 1960). [1] The reason refineries use these processes in tangent with one another is because of their abilities to process different feedstocks, their similar refining objectives, and ultimately their final products.

Out of these two processes used today, Catalytic Cracking is the most popular refining method which produces 35 to 45% of United States naphtha production. The main feedstock that a Fluid Catalytic Cracker (FCC) uses to produce these distillate products are paraffinic atmospheric and vacuum gas oils. [1] The reason that a catalytic cracking process was even invented was because of the low octane gasoline yields and high possibility for coke formation in the distillation columns that occurred in thermal cracking. The catalysts that are used in the cracking processes can be separated into three classes, those being; acid-treated natural aluminosilicates, amorphorous synthetic silica-alumina combinations, and crystalline synthetic catalysts (zeolites). In regards to today’s FCC process, they most commonly use the zeolite class catalyst to break apart the long chained feedstock while utilizing a regenerator, a reactor, and fractionator. All of these units increase the thermal efficiency and allow for the main objectives, which are to increase high octane gasoline yield, to lower coke yield, to increase isobutene production, and to allow for higher conversions without over cracking, to be reached. [1] The final products following the FCC process are Gas, Gasoline, LCO, HCO, and Decant Oil.

The purpose of Hydrocracking is to work along with Catalytic Cracking and allow for all types of hydrocarbons to be refined into light to middle distillates. Hydrocracking uses feed stocks such as aromatic cycle oils and coker distillate (feedstocks that aren’t used in FCC). Before hydrocracking can be performed, all feeds have to be hydro treated in order to remove metallic salts, oxygen, organic nitrogen compounds, and sulfur to prevent catalyst poisoning. [1] Once the feedstock is treated, hydrocracking can be done in a single or two stage process. In a single-stage process, a single catalyst is used to convert the feed into gasoline and lighter products, and in a two-stage process multiple catalysts are used to recycle the reactor bottoms back into the reactor to further refine the heavier hydrocarbons to produce the desired yield of distillates. The ultimate objectives of Hydrocracking it to improve the gasoline boiling-range, to improve gasoline pool octane quality, to produce less coke, and to re-use the heavier by-products from Catalytic Cracking to produce a useable fuel. [1] In the grand scheme of things, the final product in Hydrocracking can be dependent on what fuel is needed. Most of the time hydrocracking produces products similar to those formed from Catalytic Cracking including gasoline, jet fuels, and diesel. [1]

Resources:
1. Gary, J. H., & Handwerk, G. E. (2007). Petroleum refining: technology and economics. New York: M. Dekker.

The Uses for Thermal Cracking in Past and Present Refineries

Posted on June 28, 2014 by Brody Jack Miller

Thermal cracking is a useful step in the petroleum refining which allows for the “seemingly useless” vacuum distillation residue (VDR) to be converted into distillate fuels and coke. In today’s petroleum refinery, thermal cracking is primarily used for the production of coke. The two processes used to create this coke are delayed coking and fluid coking. These processes are operated at relatively low pressures (just slightly above atmospheric) and at a temperatures just above 900 degrees Fahrenheit. Depending on the duration of these processes, petroleum coke can be made into fuel-grade coke or, after further processing, anode-grade coke which can be used in batteries. In 2012, coking exports accounted for 19% of our nation’s petroleum exports. [1]

However, thermal cracking of petroleum fuels wasn’t always primarily used for the production of coke. In 1913, thermal cracking was used for means of distillate fuel production. [2] Since the “gasoline boom” was occurring during this time, refineries had to find ways to compensate for the increasing demand of fuel. This thermal cracking process also utilized low pressures and high temperature to break apart heavy fuel, otherwise known as visbreaking, in order to make the smaller chained gasoline molecules. The problem facing thermal cracking in gasoline production is the resulting low octane number. In 1930, thermal cracking was replaced by catalytic cracking because of its higher gasoline yield and higher resulting octane numbers. [2]

Sources:
1. U.S. Energy Information Administration – EIA – Independent Statistics and Analysis. (n.d.). Coking is a refinery process that produces 19% of finished petroleum product exports. Retrieved June 28, 2014, from http://www.eia.gov/todayinenergy/detail.cfm?id=9731
2. Petroleum Refining Process. (n.d.). Petroleum Refining Process. Retrieved June 28, 2014, from http://www.ilo.org/oshenc/part-xii/oil-and-natural-gas/item/384-petroleum-refining-process

The removal of wax from feed stocks using solvents and catalytic dewaxing processing

Posted on June 21, 2014 by Brody Jack Miller

After my one Penn State laboratory class where we chilled different hydrocarbons to measure the cloud point (temperature at initial wax formation) and pour point (temperature at which hydrocarbon became practically solidified) it was determined that the cold resistance of fuel from forming wax was an important property of a hydrocarbon. In a real life application hydrocarbons are enhanced by additives to resist the wax (long-chain paraffin) formation. Before any additives are blended into fuels they undergo a solvent or catalytic dewaxing processes.

The first method for dewaxing is by using the physical process of solvent dewaxing. The two main solvents that are used in the solvent dewaxing process are propane and ketones (either methyl ketone with methyl isobutyl ketone or methyl ketone with toluene.) The object of solvent dewaxing to mix the solvents with the deasphaling oil, which will dilute the feedstock reducing viscosity, and then the mixture is cooled down until wax is formed. [1] Once the wax was formed it is sent into a rotating drum that forces the wax crystals to the outside where I can be extracted. The most economical way to perform this process is by using Dilchill dewaxing. Dilchill dewaxing is a process that injects cold solvent into DAO stream where it is highly agitated forcing the formation of larger wax crystals.[1]

Another way to extract wax from DAO is by Catalytic Dewaxing. Catalytic dewaxing is the chemical process that uses hydrocracking, performed by zeolite catalysts, to break apart the long chained n-paraffins to form branched i-paraffins. As mentioned before, this will cause the cloud point and pour point to be reduced. Going one step further, catalytic cracking can use two enzymes for the reduction of pour point and to also improve on the oxygen stability of the DAO. [1] Catalytic dewaxing the the preferred process compared to solvent dewaxing because it has a better yield and is a cheaper overall process.

Sources:
1. Gary, J. H., & Handwerk, G. E. (2007). Petroleum refining: technology and economics. New York: M. Dekker.

Product removal from applying solvents and non-polar solvents to a feedstock

Posted on June 21, 2014 by Brody Jack Miller

Solvent fractionation is the process in which solvents, such as n-heptane, n-pentane, and propane, are used to further separate the feedstock that comes from the initial distillation process. The most common application for solvent fractionation is performed on the vacuum distillation residue. The reason that this feedstock is distilled further is because it can create different marketable products such as asphalt (from asphaltene), resins, and oil (used for lubrication and other products). The way that these distillates are separated, from the aromatic solvents of benzene and toluene, occurs in three stages which blend the feedstock with increasingly lighter paraffinic solvents. The first stage is using n-heptane to separate the solid asphaltene product from the VDR feedstock. The portions, such as n-heptane maltenes, which are soluble in the heptane solvent, are introduced to n-pentane. N-pentane allows for hard resin to be separated from the feedstock, and allows for further separation of the soluble products to finally be treated with propane to separate the feedstock into soft resin and oil.
In order to further understand how asphaltenes are extracted from the feedstock, with the use of n-heptane, n-pentane, and propane, one would need to use the Hildebrand Solubility Parameters. These parameters are used to determine the solvent power of these non-polar solvents and how the different carbon numbers define the power of the solvent. The Hildebrand Solubility Parameters use the characteristics of surface tension, molar volume, and energy of vaporization to be able to decide which solvent is best for asphaltene and resid extraction. Ultimately, the goal for this process is to obtain the highly usable deasphalted oils so that they can be further processed to make lube oil base stock and distillate fuels. Most of the deasphalting process is conducted by propane and then is further processed by furfural, phenol, and N-methyl-2-pyrrolidone solvents to separate the high carbon aromatics from the naphthenic and paraffinic ones. [1]
Sources:
1. Gary, J. H., & Handwerk, G. E. (2007). Petroleum refining: technology and economics. New York: M. Dekker.

The Importance of a Vacuum Distillation Unit after the CDU

Posted on June 14, 2014 by Brody Jack Miller

In every refinery there are two distillation processes, the first process goes through the Crude Distillation Unit (CDU) followed by the Vacuum Distillation Unit (VDU). The CDU uses flash characteristics to separate the crude into a vapor and liquid stream. The liquid stream is then introduced to steam to further separate it from the low boiling distillates and the heavier components. The reheated 730-850⁰F heavier components are then further distilled in the VDU to prevent cracking which causes coke to form on the metal distillation columns. Normally, distillation happens at 25 to 40 mmHg but to improve the vaporization the pressure is lowered to 10mmHg or less in the VDU. In the VDU, steam and high tube velocities are used to minimize thermal cracking and subsequently the formation of coke. The VDU can be characterized in three different operations; dry, wet, and damp. Dry operation does not use steam and has the highest furnace outlet temperatures, Wet operation use steam and has the lowest furnace outlet temperature, and damp operation is the combination of the two. [1]
Since the overall goal of the VDU is to prevent coke formation during crude distillation, the Watson Characterization Factor is used to estimate these temperature limits. The temperature limits are usually set to where the temperature of the crude is lower than the lowest temperature that initializes the decomposition zone. Another use of the Watson Characteristic Factor in the VDU process is that it characterizes the thermal reactivity of the crude. Crude with a high Kw factor is highly paraffinic which stresses a lower distillation temperature. Whereas, crude with a lower Kw factor is less likely to thermally crack and produce coke and can withstand a higher distillation temperature.
Sources:
1. Gary, J. H., & Handwerk, G. E. (2007). Petroleum refining: technology and economics. New York: M. Dekker.

The Importance of Different Distillation Methods in the Crude Refining Process

Posted on June 14, 2014 by Brody Jack Miller

Crude oil is a very complex mixture of different hydrocarbons and because of this complexity there are multiple methods to distill barrels of crude into their different fuel fractions. The three methods that refineries use are True Boiling Point Distillation (TBP), ASTM Distillation (ASTM) and Equilibrium Flash Vaporization (EFV). These methods, as shown above, are in a decreasing order of significance. This means that the each method produces a different degree of separation with true boiling point being the most efficient.
True Boiling Point is a batch process that uses the physical properties of the different components of crude to separate it into its different fractions with the use of over 100 plates or a reflux ratio of 100. Another positive to distilling crude in this method is that the crude is able to be distilled at a constant temperature (due to the high number of plates) and a crude mixture would be able to be distilled as individual components where temperature is adjusted accordingly.
An ASTM Distillation process is very similar to TBP except that it does not use any plates, and has a reflux ratio of 0. This process condenses the vapors of the crude but because of the lack of plates, the temperatures are not as constant making it less effective to fractionate the crude than that of the TBP method.
The Equilibrium Flash Vaporization process allows for the crude to vaporize separating the components into gas and liquid components. As the gas travels up the stack, it comes in contact with heat exchangers which use a cold fluid to condense the vapors into its separate fuels. Each individual fuel side stream has a decreasing reflux. [1] This method has the lowest crude separation.
Sources:
1. Gary, J. H., & Handwerk, G. E. (2007). Petroleum refining: technology and economics. New York: M. Dekker.

The U.S Dependency on Foreign Oil and the Environmental Impacts from Petroleum Refining

Posted on May 25, 2014 by Brody Jack Miller

Since the drilling of the first petroleum well in Titusville, Pa, the United States has become increasing more dependent on the “liquid gold”. In order to quench the appetite for the gasoline and diesel demand of internal combustion engine use, a refinery had to be built.[1] The purpose of these refineries are to increase the yield of desired products, while removing harmful compounds that can affect the environment during the combustion process. In order to understand the importance of refineries, this entry will summarize the dependency of foreign crude imports, the compositions of a barrel of crude oil, and finally the methods used in a refinery process/ their purposes.

In 2013 the United States consumed roughly 6.89 billion barrels of refined crude oil products.[2] Of these 6.89 billion barrels of crude oil, the majority of the supply did not come from the foreign imports. This was shocking because traditionally the United States imported roughly 60% of its demand from foreign countries.1 As of 2012, the United States only relied on foreign sources for 40% of its total crude consumption.[3] The reason for this drastic change could be due to many reasons but, to me, the biggest catalyst for this change was the United States economic recession in 2008. The price per barrel of crude oil was steady trending upward, but in 2008 a barrel of crude drastically rose from $66.52 to $94.04.[4] This large increase of price may have been a driver that forced the United States to steer away from foreign imports and produce more domestic oil/ research alternative fuels such as natural gas.

The term “Barrel” in the petroleum field refers to a drum that contains 42 gallons of crude oil.[5] Within that crude oil there are multiple components that can be extracted after the refining process. A single barrel of crude can contain roughly 50% gasoline, 15% distillate fuel oil (diesel fuel and heating oil), 12% jet fuel, and trace amounts of other compounds.[5] Based on the demand of a specific type of fuel a refinery will be able to tailor its production to accommodate for the specific fuel need.

Up until the establishment of the first U.S oil refinery, built in 1861, petroleum products weren’t so easily separated into a desired fuel.[1] In order to grasp the importance of refining it is necessary to understand the five basic steps of the refining process and ultimately the impact certain steps have on the environment after the fuel is combusted. The five steps in the refining process are distillation, conversion processing, treatment, blending, and compound extraction from other refining options. Distillation is the process that separates fuels based off of their boiling point and compound sizes; Conversion processing is used to manipulate chemical structures to form different fuels from thermal cracking, catalytic cracking, and other methods; Treatment processing is used to remove any undesired compounds and chemicals from the fuels; Blending allows for the fuel to be improved for performance and temperature conditions with the introduction of additives; and compound extraction processing allows for the recovery of certain compounds and the treatment of various refinery fluids. Of the five processes, the treatment process of the crude has the most environmental impact. During this process, the fuels undergo procedures to remove wax, sulfur, disulfides, and coke.[1] The removal of these compounds allow for there to be a reduced production of harmful emissions such as carbon monoxide and sulfur dioxide during the combustion process. For example, currently 60% of the diesel produced is of low sulfur content (15 ppm).[1]

1. Gary, J. H., & Handwerk, G. E. (2007). Petroleum refining: technology and economics. New York: M. Dekker.
2. How much oil is consumed by the United States?. (n.d.). . Retrieved May 14, 0025, from www.eia.gov/tools/faqs/faq.cfm?id=33&t=6
3. How dependent is the United States on foreign oil?. (n.d.). . Retrieved May 14, 0025, from www.eia.gov/tools/faqs/faq.cfm?id=32&t=6
4. U.S crude oil first purchase price. (n.d.). . Retrieved May 14, 0025, from www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=pet&s=f000000__3&f=a
5. What does one barrel of crude oil make?. (n.d.). . Retrieved May 14, 0025, from http://www.californiagasprices.com/crude_products.aspx

FSC 432: Petroleum Refining

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