Advanced computer systems with applications software augment these services. They can be offered as part of the well site and office based services with configuration to a Client’s specific needs. The online computerized unit (PSL system) can be installed in various forms depending on Client requirements. The PSL system is an intelligent, multi-tasking, real time data acquisition and monitoring system. It accepts inputs from all the sensors and provides real time monitoring with audio-visual alarms and error messages of parameters with output to 18” LCD & 20” Monitors, chart recorders, and printers.
All data variables and interval averages are directly stored in a non-volatile data memory buffer. These are accessed by the applications computers, for data manipulation, permanent data storage, plotting and running applications software (DPIC®).
The Online Server Network Station with DTCIS software® creates a comprehensive database of all drilling and geological parameters on 500 GB hard disk with floppy (1.44 MB) and DVD (8.5 GB) disk back up. Full database management and editing is effected and a range of application programs run to enhance analysis and data interpretation. Real time, color graphic displays are available with the Server Network Station. It displays and stores selected time based information at 2-second intervals.
The scope of the logging systems can be expanded through the transmission to a town office system. Data can be transferred via Dial up communications as well as LAN connections, or just by disc update in ASCII format. When rig operations dictate, printed reports and real time displays (graphic screens) can be produced in the Town office on call by the user. In addition, through batch transfer, time or depth related parameters, can be received on the office PC with full access to all applications software, including log plots, and data printouts. PS Field Staff highly trained, with expertise and experience provides the best in performance drilling. The personnel involved have many areas of expertise: geology, formation evaluation, drilling, pressure evaluation, electrical and Log analysis.
PETROGAS has years of experience in designing and building modular distillation systems. PETROGAS designs systems to meet your application, and builds its units to suit your needs.
Transmix Distillation is a simple process of using heat to separate light hydrocarbon products from a diesel or similar interface fluid.
PETROGAS can work in any size range and any metal or alloy to produce a distillation system that predictably distills fluids.
RICH OIL is sent to a STRIPPER where the absorbed vapors are removed by heating the RICH OIL, vaporizing the absorbed vapors. The rich oil is, thus, regenerated as lean oil and recycled to the ABSORBER to complete the process loop. The vaporized vapors are liquefied and transferred to storage.
PETROGAS Absorption Systems are designed to operate continuously, or intermittently, in a fully automatic mode. PETROGAS offers a basic system, with options to allow each unit to be customized to meet your unique specifications at a fraction of the cost of a custom designed and fabricated system.
PETROGAS systems have proven superior efficiency in the recovery of hydrocarbons and chemicals from vapor streams. PETROGAS Absorption Systems are supplied as complete factory package units, including instrumentation, piping and electrical, on a structural skid.
Gas absorption is an operation in which a soluble component of a gas is dissolved in a liquid.
The PETROGAS absorbent liquid (Lean Oil) selectively absorbs propanes+, or other selected components, from a natural gas stream in accordance with the client specifications for meeting pipeline specifications (by control of the BTU or reduction of the pentanes+) or the economic benefit of the spread between selling liquids as a gas or as a liquid.
The PETROGAS Model A System is available to process natural gas stream flow rates of 5 mcfd to 5,000 mcfd.
Gas liquids recovery units are intended to help you meet pipeline sales specifications and/or recover valuable marketable liquids from natural gas. PETROGAS is a recognized leader since 1975, in the design, manufacturing and operation of gas liquids recovery Mini-Plants.
Many natural gas purchasers restrict the liquid content of natural gas entering a gathering system. The restrictions are expressed as thermal value (BTU) and/or pentanes and heavier content. These restrictions are intended to prevent the dangerous condensation and accumulation of liquids in gas transmission lines.
| COMPOSITION BTU / SCF | RECOVERY RATE GAL/MCF | TYPICAL SOURCE |
|---|---|---|
| 3000 | 24 | Storage Tanks |
| 2000 | 12 | Heater Treater |
| 1500 | 5 | Casting Head |
| 1300 | 3 | LP Separator |
| 1200 | 2 | Gas Wells |
Gas Wells: Natural Gas not meeting pipeline specifications with high gas liquids may be conditioned using a PETROGAS Mini Plant. Operators are not fully compensated for liquid components of a natural gas stream. PETROGAS NGL Recovery Plants allow the lease operator to recover liquids prior to the sale of gas. Are your gas sales restricted? Produce more, sell more when you recover liquids
Gas Gathering Systems: Gas pipeline flow rates may be too low to justify a custom constructed plant. PETROGAS NGL Recovery Plants cost less because they are standardized, factory assembled skid modules. Reserve life too short for a custom plant? PETROGAS Plants can be easily moved as the location becomes uneconomical. Casing Head Gas System economies can be greatly improved by liquids recovery. Casing Head gas is normally rich in recoverable liquids.
Injection Gas Stripping: When gas is injected into a formation for storage or repressurization, removal of liquids will reduce equipment maintenance and potential formation blockage. Recovered liquids generate NOW income, not a possible future reserve. Gas lift recycled gas is more effective when the gas liquids are removed and produce extra revenue, too!
Process Gas: Plants receiving fuel from unprocessed sources will encounter excessive maintenance of boilers, injection jets and carbonation of engines. Maintenance can be reduced and additional revenues generated by liquids removal using a PETROGAS NGL Recovery Plant.Improve the quality of METHANE-ETHANE feed stock by the controlled removal of Propane-Butane-Gasoline. Produce a source of Propane-Butane-Gasoline for local consumption.
Fuel Gas Cleaning: Produced natural gas is often too rich in heavier hydrocarbons to be used effectively as a fuel for internal combustion engines. The heavier hydrocarbon components, pentanes, hexanes and heavier will cause excessive carbon deposits and foul engine fuel injection systems, cylinders, etc. Excessively high BTU or pentanes+ fuel gases may void your engine warranty or restrict rentals of natural gas driven equipment, i.e. compressors, generators, etc. PETROGAS offers Fuel Gas Cleaning Systems to remove pentanes+ and give you a fuel gas that will be clean burning and reduce engine maintenance.
Flared or Vented: Low pressure gas from well's casing head, separators, treater, and tank battery vented or flared is more significant than is generally realized. These wasted gases can be processed through a PETROGAS NGL Recovery Plant and yield sizeable revenues to the operator.
Tank Vapor Recovery: Tank vapors emitted to the atmosphere are a significant source of lost revenue and an air pollutant. Recovery by compression has proven to be costly and ineffective. The vapors when compressed return to a liquid state in the pipeline or separator and again vaporize if returned to low pressure storage. Vapors recovered by a PETROGAS Mini-Plant are sold as liquids.
During loading of motor gasoline at underground storage tanks located at our stations, the liquid introduced displaces vapors from previous loadings that still exist in the tank and those vapors generated by the current product loading. These vapors contain some volatile organic compounds (VOCs). The Clean Air Act of 1990 requires the control of VOC emissions, and the refinery's Marketing Terminal's Vapor Recovery unit meets Clean Air Act (Title 33, Code of Federal Regulations, Part 154) requirements.
As a tank truck drops (delivers) new product into the underground storage tank at Chevron stations, the vapors created during the drop are pushed back into the tank truck and stored there.
As the tank truck loads new product at the Marketing Terminal using a "bottom loading" method, the product being loaded into the bottom of the tank pushes the collected vapors into a vapor recovery hose connected to the recovery system. The Adsorb/Absorb vapor recovery unit condenses the vapors, recovering about 2 gallons of gasoline per 1000 gallons loaded product.
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 vapor recovery system |
Using the latest electronic technology to monitor and control the plants, operators run the process units around the clock, 7 days a week. From control rooms located in each Operations area, operators use a computer-driven process control system with console screens that display color interactive graphics of the plants and real-time (current) data on the status of the plants. The process control system allows operators to "fine tune" the processes and respond immediately to process changes. With redundancy designed into the control system, safe operations are assured in the event of plant upset.
Most refineries, regardless of complexity, perform a few basic steps in the refining process: DISTILLATION, CRACKING, TREATING andREFORMING. These processes occur in our main operating areas – Crude/Aromatics, Cracking I, RDS/Coker, Cracking II, and at the Sulfur Recovery Unit.
 Pascagoula Refinery skyline |
Modern distillation involves pumping oil through pipes in hot furnaces and separating light hydrocarbon molecules from heavy ones in downstream distillation towers – the tall, narrow columns that give refineries their distinctive skylines.
The Pascagoula Refinery's refining process begins when crude oil is distilled in two large Crude Units that have three distillation columns, one that operates at near atmospheric pressure, and two others that operate at less than atmospheric pressure, i.e., a vacuum.
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During this process, the lightest materials, like propane and butane, vaporize and rise to the top of the first atmospheric column. Medium weight materials, including gasoline, jet and diesel fuels, condense in the middle. Heavy materials, called gas oils, condense in the lower portion of the atmospheric column. The heaviest tar-like material, called residuum, is referred to as the "bottom of the barrel" because it never really rises.
This distillation process is repeated in many other plants as the oil is further refined to make various products.
In some cases, distillation columns are operated at less than atmospheric pressure (vacuum) to lower the temperature at which a hydrocarbon mixture boils. This "vacuum distillation" (VDU) reduces the chance of thermal decomposition (cracking) due to over heating the mixture.
As part of the 2003 Clean Fuels Project, the Pascagoula Refinery added a new low-pressure vacuum column to the Crude I Unit and converted the RDS/Coker's VDU into a second vacuum column for the Crude II Unit. These and other distillation upgrades improved gas oil recovery and decreased residuum volume.
Using the most up-to-date computer control systems, refinery operators precisely control the temperatures in the distillation columns which are designed with pipes to withdraw the various types of products where they condense. Products from the top, middle and bottom of the column travel through these pipes to different plants for further refining.
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Since the marketplace establishes product value, our competitive edge depends on how efficiently we can convert middle distillate, gas oil and residuum into the highest value products.
At the Pascagoula Refinery, we convert middle distillate, gas oil and residuum into primarily gasoline, jet and diesel fuels by using a series of processing plants that literally "crack" large, heavy molecules into smaller, lighter ones.
Heat and catalysts are used to convert the heavier oils to lighter products using three "cracking" methods: fluid catalytic cracking (FCC), hydrocracking (Isomax), and coking (or thermal-cracking).
The Fluid Catalytic Cracker (FCC) uses high temperature and catalyst to crack 63,000 barrels (2.6 million gallons) each day of heavy gas oil mostly into gasoline. Hydrocracking uses catalysts to react gas oil and hydrogen under high pressure and high temperature to make both jet fuel and gasoline.
Also, about 58,000 barrels (2.4 million gallons) of lighter gas oil is converted daily in two Isomax Units, using this hydrocracking process.
We blend most of the products from the FCC and the Isomaxes directly into transportation fuels, i.e., gasoline, diesel and jet fuel. We burn the lightest molecules as fuel for the refinery's furnaces, thus conserving natural gas and minimizing waste.
In the Delayed Coking Unit (Coker), 105,000 barrels a day of low-value residuum is converted (using the coking, or thermal-cracking process) to high-value light products, producing petroleum coke as a by-product. The large residuum molecules are cracked into smaller molecules when the residuum is held in a coke drum at a high temperature for a period of time. Only solid coke remains and must be drilled from the coke drums.
Modifications to the refinery during its 2003 Clean Fuels Project increased residuum volume going to the Coker Unit. The project increased coke handling capacity and replaced the 150 metric-ton coke drums with new 300 metric-ton drums to handle the increased residuum volume.
The Coker typically produces 6,200 tons a day of petroleum coke, which is sold for use as fuel or in cement manufacturing.
While the cracking processes break most of the gas oil into gasoline and jet fuel, they also break off some pieces that are lighter than gasoline. Since Pascagoula Refinery's primary focus is on making transportation fuels, we recombine 14,800 barrels (622,000 gallons) each day of lighter components in two Alkylation Units. This process takes the small molecules and recombines them in the presence of sulfuric acid catalyst to convert them into high octane gasoline.
The products from the Crude Units and the feeds to other units contain some natural impurities, such as sulfur and nitrogen. Using a process called hydrotreating (a milder version of hydrocracking), these impurities are removed to reduce air pollution when our fuels are used.
Because about 80 percent of the crude oil processed by the Pascagoula Refinery is heavier oils that are high in sulfur and nitrogen, various treating units throughout the refinery work to remove these impurities.
In the RDS Unit's six 1,000-ton reactors, sulfur and nitrogen are removed from FCC feed stream. The sulfur is converted to hydrogen sulfide and sent to the Sulfur Unit where it is converted into elemental sulfur. Nitrogen is transformed into ammonia which is removed from the process by water-washing. Later, the water is treated to recover the ammonia as a pure product for use in the production of fertilizer.
The RDS's Unit main product, low sulfur vacuum gas oil, is fed to the FCC (fluid catalytic cracker) Unit which then cracks it into high value products such as gasoline and diesel.
Octane rating is a key measurement of how well a gasoline performs in an automobile engine. Much of the gasoline that comes from the Crude Units or from the Cracking Units does not have enough octane to burn well in cars.
The gasoline process streams in the refinery that have a fairly low octane rating are sent to a Reforming Unit where their octane levels are boosted. These reforming units employ precious-metal catalysts ‑ platinum and rhenium – and thereby get the name "rheniformers." In the reforming process, hydrocarbon molecules are "reformed" into high octane gasoline components. For example, methyl cyclohexane is reformed into toluene.
The reforming process actually removes hydrogen from low-octane gasoline. The hydrogen is used throughout the refinery in various cracking (hydrocracking) and treating (hydrotreating) units.
Our refinery operates three catalytic reformers, where we rearrange and change 71,000 barrels (about 3 million gallons) of gasoline per day to give it the high octane cars need.
A final and critical step is the blending of our products. Gasoline, for example, is blended from treated components made in several processing units. Blending and Shipping Area operators precisely combine these to ensure that the blend has the right octane level, vapor pressure rating and other important specifications. All products are blended in a similar fashion.
In the refinery’s modernly-equipped Laboratory, chemists and technicians conduct continuous quality assurance tests on all finished products, including checking gasoline for proper octane rating. Techron®, Chevron’s patented performance booster, is added to gasoline at the company’s marketing terminals, one of which is located at the Pascagoula Refinery.
