Pilot Plant Man

Accelergy awarded $1.3M Grant to Build Pilot Facility - - Intertek provides technical support.

2011-04-28T12:43:00.000-07:00

HOUSTON & PITTSBURGH--(BUSINESS WIRE)-- Accelergy Corporation, a global leader in the production of high-grade, domestically sourced liquid fuels, today announced it has received a $1.3 million grant from the Commonwealth of Pennsylvania to move forward on the construction of a facility to demonstrate its integrated coal-biomass-to-liquids (CBTL) technology platform at Intertek PARC, located at the U-PARC facility in Pittsburgh.

Previously, Accelergy was awarded a $175,000 grant to conduct a feasibility study and determine the facility’s location. The new grant will allow Accelergy and its partners to showcase their fully integrated process for converting coal to liquids, and inform plans to develop commercial-scale facilities in the state.
“This grant is a strong endorsement of Accelergy and its partners’ technology, and shows the commitment of the Commonwealth of Pennsylvania to the development of advanced technologies that leverage the state’s abundant natural resources and will bring jobs to the state,” said Tim Vail, CEO of Accelergy. “We are laying the foundation for the commercialization of the domestically sourced fuels that will power U.S. fleets and help the United States achieve its energy security goals.”

“Intertek is proud to provide technical and scientific pilot plant and laboratory support for Accelergy for this exciting coal-biomass-to-liquids fuel project,” said Dr. Robert Absil, the General Manager of the Intertek PARC facility.

The facility will produce and test several types of non-petroleum fuel, including gasoline, diesel and jet fuel, and feature a carbon dioxide capture and recycle process utilizing algae to convert the carbon dioxide into additional liquid fuels and a bio-fertilizer.

Energy Strategy Environment LLC (ESE), a systems integration provider, will be responsible for bringing together the technologies and business partners for the algae based carbon capture and recycle components of the project.

“Recycling industrial CO2 emission into valuable carbon feedstocks for production of additional liquid fuels creates a sustainable pathway for CBTL,” said ESE founder Mark Allen, P.E. “Algal biomass from the project will be adapted for use as a natural bio-fertilizer with the potential to reduce the use of synthetic nitrogen fertilizer and to sequester carbon in agricultural soils and reclaimed mine site soils, further benefitting the environment.”

The grant was approved with a unanimous vote from the Pennsylvania Commonwealth Financing Authority. Accelergy has been in talks with various state politicians since early 2010, when former State Rep. Dave Kessler first brought the company to Pennsylvania. Kessler has since formed Advanced Energy Initiatives LLC and now represents the company in Pennsylvania.

“The grant represents a strong level of bipartisan support from both sides of the aisle, and we are grateful to state legislators and Gov. Corbett for their endorsement of this project,” Dave Kessler said. “Accelergy’s process and the resulting fuels would be much cleaner than refining imported oil or drilling for oil off America's shores, and the potential for this technology in Pennsylvania is enormous.”

Accelergy’s technology addresses the simultaneous challenges of increasing the supply of secure fuels while reducing greenhouse gas emissions. The integration of CBTL technology and carbon capture and recycling processes using algae photobioreactors to recycle CO2 makes it possible to produce abundant cleaner fuels from domestic resources.

The company currently has agreements in place with the U.S. Air Force Research Laboratory and the U.S. Army Tank Automotive Research, Development and Engineering (TARDEC) Center to test and certify the resulting fuels for various applications.

About Accelergy Corp.:
Accelergy is a global leader in producing ultra-clean synthetic fuels, promoting energy security by using domestic resources. Our proprietary catalytic technology significantly increases the efficiency of the Coal-Biomass-to-liquid process (CBTL) while significantly reducing greenhouse emissions. Based in Houston, Texas, Accelergy has established an international presence in partnerships with some of the world's leading energy companies. For more information, please visit www.accelergy.com.

About Energy Strategy Environment LLC:
Energy Strategy Environment is a Colorado based systems integration provider bringing together the technologies, processes, and business partners to deliver scalable-engineered carbon capture and recycle solutions that monetize industrial CO2 emissions into profitable revenue streams. Founder and CEO, Mark P. Allen, P.E., is an industry expert in assessing technologies and processes that utilize CO2 from industrial sources to grow algal biomass and produce fuels and terrestrial carbon sequestration solutions. For more information please contact Mark Allen at markallen87@mac.com.

About Intertek:
Intertek (ITRK.L) is a leading provider of quality and safety solutions serving a wide range of industries around the world. From auditing and inspection, to testing, quality assurance and certification, Intertek people add value to customers' products and processes, supporting their success in the global marketplace. Intertek has the expertise, resources and global reach to support customers through its network of more than 1,000 laboratories and offices and over 27,000 people in more than 100 countries. Intertek PARC has provided pilot plant testing services to the global oil, refining and biofuels industries since 1986.

Question regarding metals causing high conductivity in crude oil.

2011-04-06T07:28:00.000-07:00

Question:

I would like to know besides Na, Ca and Mg which major metals or materials can cause high conductivity in crudes consequently affecting the desalter operation efficiency. Is it wise to know and monitor the metals distribution?

Comments:

Water in crude oil increases conductivity³. Metals in crude oil can be present as inorganic or organic compounds and include vanadium, nickel and iron. The vanadium and nickel are mostly present as porphyrins. The crude oil also contains asphaltenes with polyaromatic cores containing nitrogen, sulfur, oxygen, vanadium and nickel. The polyaromatic cores are believed to interact strongly with electrical fields^1,2 and thus negatively impact desalter operation.

Dilution of low conductivity crudes with toluene or DOBA crude resulted in substantial increases in electrical conductivity (cf. Reference 3). This increase in conductivity may be due to dissociation of the asphaltene aggregates, thereby exposing “the active sites” that interact strongly with the electric fields and that are otherwise shielded by the asphaltene aggregate structure or are complexed with resins¹. This shows that electrical conductivity numbers are not necessarily additive when blending different crudes at the refinery to meet total acid number specs.

References:

Hasnaoui, N., Achard, C., Rogalski, M., and Behar, Revue de L’Institute Francais Du Petrole. 1998, 53(1), Jan-Feb.
Kendall, E. J.M., Journal of Canadian Petroleum, 1978, July-Sept, p. 37-38
Potter, A.C., Crude Oil Conductivity Presentation, February 2007, retrieved from Internet.

Using "Green Chemistry" for Renewable Fuel Feedstocks

2010-10-08T07:36:00.000-07:00

Catalysis and "Green Chemistry" technologies play a key role when producing biofuels processed from renewable feedstocks.

By Rob Absil, Director of Intertek PARC

When thinking of “green chemistry”, well-known concepts that come immediately to mind are waste prevention, energy efficient design and product degradation. An example of product degradation is biodegradable plastics. Another well-publicized concept is sustainability. The use of renewable feedstocks is at the forefront of R&D today to develop sustainable bio-fuels.

Catalysis research plays a key role by developing homogeneous or, even more preferable, heterogeneous catalysts for these applications. The advantages of heterogeneous catalysts are that they are usually high surface-area solids that can be readily separated from the products, resulting in energy savings. However, they must be sufficiently active and selective to be economically viable.

A “green chemistry” concept probably less familiar to the chemical engineer is that of “atom economy.” Consider the following reaction with product C as the desired product ^[1]:

aA + bB à cC + dD

Then, the following performance criteria are:

% Yield = 100 * Actual Quantity of Product C Produced .

Theoretical Quantity of Product C Achievable

% Selectivity = 100 * Yield of Product C .

Amount of A Converted

% Atom economy = 100 * c * Molecular weight of C

(a * Molecular weight of A + b * Molecular weight of B)

Thus atom economy maximizes the incorporation of materials used in the process into the desired product^[1].

Intertek PARC offers a portfolio of pilot plant capabilities that include fixed bed reactors as well as autoclaves of various capacities. Rapid, initial screening can be provided to identify leads that can then be explored for further development.

For more information, please visit: http://www.intertek.com/testing/pilot-plant/new-technologies/

Reference:

Lancaster, M., Green Chemistry: An Introductory Text, Royal Society of Chemistry, Great Britain, 2002 and references cited therein.

Pilot Plant White Paper: Mitigation of Technical Risks

2010-09-07T11:08:00.000-07:00

Risk Mitigation when Implementing New Process Technologies in Refineries and Chemical Plants.

This new White Paper by Rob Absil, Intertek PARC, focuses on steps refiners and chemical plant operators can take to reduce technical risks from new or novel feed-stocks by using appropriate pilot plant technologies.
http://www.intertek.com/white-papers/risk-mitigation-in-refining-chemical-plants/ (.pdf download)

Petroleum Pilot Plants and Technology Risk Mitigation for Refiners and Chemical Plants

2010-09-03T07:17:00.000-07:00

By Rob Absil, Intertek PARC.

Intertek held its “Trends in the Energy Conference 2010” on July 21 in Houston, Texas. At this conference I gave a presentation discussing how refiners have to maximize profits by manufacturing marketable products while dealing with crude oil quality changes and abiding by quality, safety, and environmental regulations set by the industry, state, and federal governments.

While the refiner has a portfolio of processes available to accomplish these goals, technical risks exist that the outcomes will not be as desired when implementing new process technologies. Independent protection layers have to be implemented to reduce these risks. An overview of technical risks in the biodiesel and refining industries and a discussion of the independent protection layer (IPL) concept used in process plant safety field have been provided in a separate paper.

The industry has been using independent pilot plant testing as an IPL to reduce risks of implementing new process technologies. Intertek PARC serves as that IPL and continues to provide independent pilot plant testing services to the global oil & refining and biofuels industries, especially to mitigate risks associated with new feedstocks, such as bitumen, shale oil and biomass-sourced materials.

Intertek PARC offers confidential screening of new process technologies. Fixed bed reactors and batch reactors are available for catalyst evaluations; feedstock analyses are provided by Intertek PARC and its sister laboratories. Furthermore, bulk and surface science techniques provided by Intertek ASA in the Americas and Intertek MSG in Europe can be used to characterize catalyst formulations. These combined services allow for rapid generation of new research leads.

Links in paper:

Presentation links to the Energy Conference webpage

White Paper:
"Risk Mitigation When Implementing New Process Technologies in Refineries and Chemical Plants"
http://www.intertek.com/white-papers/risk-mitigation-in-refining-chemical-plants/

Fixed bed reactors:
http://www.intertek.com/testing/catalyst/heterogeneous-catalyst/

Batch reactors:
http://www.intertek.com/testing/pilot-plant/batch-reactor/

Feedstock analysis:
http://www.intertek.com/petroleum/testing/crude-oil-and-feedstocks/

Intertek ASA links:
http://www.intertek.com/testing/catalyst/heterogeneous-catalyst/

Intertek MSG links:
http://www.intertek.com/testing/catalyst/

Corrosion Assessment of a Process

2010-08-04T11:42:00.000-07:00

A corrosion assessment of a process typically focuses on the feed and products. However, the impact of reaction intermediates must also be considered. Let’s consider a plug flow reactor in which the series reaction A -> B -> C takes place. Assuming the reactions are first order and irreversible, then the following set of equations models the reaction system [1]:

Ca/Cao = exp (-k1 * η)
Cb/Cao = k1/(k2-k1) * [exp (-k1 * η) - exp (-k2 * η)]
Cc = Cao – Ca – Cb

η is defined as V/νo. According to this scheme, Ca decreases along the length of the reactor, while Cb reaches a maximum and then decreases and Cc increases along the length of the reactor. The maximum concentration of “b” in the plug flow reactor is determined as:

Cbmax = (k1/k2) k2/(k2-k1)

The maximum concentration of “b” depends on the k2/k1 ratio. In assessing the corrositivity of a catalytic system, the focus is typically on the feed and the products. However, depending on the reaction system the impact of the intermediate product(s), in this case product “b,” must also be considered, especially if the process is operated at 100% conversion and intermediates are not detected in the product stream.

In the conversion of triacylglycerides in vegetable oils several investigators [2, 3, 4] have concluded that the triacylglycerides first undergo hydrogenolysis over a variety of catalysts to form the corresponding fatty acids and propane. The fatty acids then undergo decarboxylation, decarbonylation or hydrodeoxygenation further down the reactor to form paraffins, carbon oxides, and/or water. Fatty acid free triacylglycerides and these products have total acid numbers (TAN) of 0 mg KOH/gr. The fatty acid intermediates are carboxylic acids that have TANs of ~200 mg KOH/gr (C18 fatty acid) and could be potentially corrosive. While these reactions are conducted in trickle bed reactors, the plug flow analysis is still applicable. These results emphasize that in the selection of the metal used to build the reactor, the reaction kinetics and the corrosion properties of intermediates must be taking into account.

Learn more about biofuel processing and pilot plant research at:
http://www.intertek.com/testing/catalysts/pilot-plant/biofuels/

References:

1. Levenspiel. O., Chemical Reaction Engineering, John Wiley & Sons, New York, 1972.
2. Morgan, et al., Topics in Catalysis, Vol. 53, No. 11-12, July 2010 (abstract retrieved from Internet on 7/18/2010)
3. Boda, et al., Applied Catalysts A: General, Vol. 374, No. 1-2, Feb., 2010, pp. 158-169.
4. Guzman, et al., Catal. Today, In press (2010).

Chemical Exposure Index (CEI) and Pilot Plants

2010-07-19T07:11:00.000-07:00

To offer Intertek PARC’s pilot plant services to the (petro) chemical industry, PARC has started to use the Chemical Exposure Index (CEI) as calculated in Dow’s Chemical Exposure Index Guide [1]. The CEI is calculated from the estimated airborne release rate of the chemical compound of interest and its ERPG-2 value. The three Emergency Response Planning Guidelines (ERPG) are defined as [1]:

“ERPG-1 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for one hour without experiencing other than mild transient adverse health effects or perceiving a clearly objectionable odor.”

“ERPG-2 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for one hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair their abilities to take protective actions.”

“ERPG-3 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for one hour without experiencing or developing life-threatening health effects.”

CEIs were calculated for a series of chemicals at a set of conservative conditions. The ERPG values of the chemicals were obtained from their Material Safety Data Sheets and were calculated as detailed in the guide. The chemicals were then grouped into four categories (A through D) according to their hazard level or CEI. As pointed out, “[a]bsolute measures of risk are very difficult to determine, but the CEI system will provide a method of ranking one hazard relative to another. It is NOT intended to define a particular design as safe or unsafe[1].” While Intertek PARC’s facility is substantially smaller than refineries or petrochemical plants, this index can still provide guidance in comparing new processes to current existing processes. Current operation has been mainly restricted to “Group A” chemicals. PARC does have extensive experience with hydrogen sulfide, a “Group B” chemical, since it is formed when hydrotreating crude oil. Hydrotreating operations producing hydrogen sulfide are typically at low effective hydrogen sulfide flow rates, reducing the hydrogen sulfide to a “Group A” chemical when considering emissions to the atmosphere.

It is important to realize that the CEI is defined for a vapor release to the atmosphere at a wind speed of 11.2 mph and at neutral weather conditions [1]. Intertek PARC’s P-84 pilot plant bank is located inside Building C4 at its Pittsburgh facility. Due to the pilot plants being located indoors, two releases exist. The first one is into the well-ventilated process area and the second one, as characterized by the CEI, is into the atmosphere via the Building C4 exhaust fans and blow down systems.

Independent layers of protection are required to safeguard the operator against potential hydrogen sulfide releases inside Building C4. An independent protection layer is defined “…as a device, system, or action that is a capable of preventing a scenario from proceeding to its undesired consequence independent of the initiating event or the action of any other layer of protection associated with the scenario [2].” Protection layers include a combination of process area hydrogen sulfide alarms, operator hydrogen sulfide monitors, airline respirators, cartridge respirators (for escape only), and alarms on the air handlers/ exhaust fans.

Learn more about Intertek PARC at: www.intertek.com/automotive/parc/

References:

1. AIChE, Dow’s Chemical Exposure Index Guide, 1st Edition, 1994.
2. AIChE, Layer of Protection Analysis, 2001.

Fixed-Bed Reactors and Trickle-Bed Mode

2010-06-14T15:39:00.000-07:00

Fixed-bed reactors operating in the trickle-bed mode are typically used in conventional oil refineries. In a trickle-bed reactor liquid feed and gas are fed co-currently in downflow over a packed bed of catalyst particles in a vertically–positioned reactor.

The following processes are used to remove sulfur, nitrogen, and oxygen compounds in feedstocks:

• Hydrodesulfurization - the conversion of sulfur compounds to hydrogen sulfide.
• Hydrodenitrification - the conversion of nitrogen compounds to ammonia.
• Hydrodeoxygenation - the conversion of oxygen compounds to water.
• Hydrotreating - the simultaneous conversion of sulfur, nitrogen and oxygen compounds.

Furthermore, olefins and aromatics in the feedstocks are converted by:

• Hydrogenation - the saturation of olefins and/ or aromatics.
• Hydrocracking - the simultaneous cracking and hydrogenation, leading to boiling point reduction and olefins and/or aromatics saturation, respectively.

Trickle-bed reactors operate with low pressure drops and at relatively high temperatures and absolute pressures. The high temperatures are required due to the low activities of the catalysts for processing crude oil-sourced feedstocks which can contain very refractory compounds. High pressures are required to increase hydrogen solubility in the liquid which is reduced by high temperature operation. One disadvantage of the trickle-bed reactor is that liquid flow and chemical kinetics can be interconnected, making scale-up difficult. One way to decouple fluid mechanics from chemical kinetics is by packing laboratory reactors with diluent particles to ensure good liquid-catalyst contacting [1].

Intertek PARC has provided fixed-bed testing services to the global oil & refining industry since 1986. Fixed-bed pilot plants with a range of reactor sizes are available for isothermal as well as adiabatic operations. Furthermore, once-through and recycle operation options for gas and liquid are available. For more information about Intertek PARC’s capabilities, please visit: http://www.intertek.com/testing/pilot-plant/a-to-z/.

Reference 2 classifies catalytic reactors according to size, methods of charging and discharging, motion of catalyst particles relative to each other and fluid flow. Upon further consideration, catalytic reactors can also be categorized according to the motion of catalyst particles relative to each other and to the motion of the catalyst particles relative to the stationary reactor wall. We can classify ideal catalytic reactors with the following table:

References:
1. Al-Dahhan, et al., Ind. Eng. Chem. Res., 1997, 36, 3292-3314.
2. www.et.byu.edu/~bartc/presentations/Catalytic%20Reactors.

Solvent Deasphalting in Petroleum Refineries

2010-05-24T07:53:00.000-07:00

Solvent deasphalting is a refinery process for extracting asphaltenes and resins from heavy vacuum gas oil, atmospheric residue or vacuum residue to produce valuable, deasphalted oil that otherwise can not be recovered from the residue by conventional distillation. The deasphalted oil can be used to make lubricants or as feed to the fluid catalytic cracker or the hydrocracker. The process consists of contacting the feedstock with a solvent in a countercurrent extractor at elevated temperature to precipitate the asphaltene and resin fractions that are not soluble in the solvent. Paraffins on the other hand are soluble in the solvent at lower temperatures, but their solubility decreases with increasing temperature. Therefore, the yield of the deasphalted oil decreases with increasing extractor temperature. Operation is typically well below the critical temperature to avoid flooding. The pressure is mainly selected to keep the solvent in the liquid phase. Typically, the quality of the deasphalted oil decreases with increasing deasphalted oil yield. Consequently, the temperature can be selected to yield deasphalted oil with the desired properties [1, 2, 3, 4]. For more information on Intertek PARC’s capabilities, please visit http://www.intertek.com/testing/ pilot-plant/thermal-heavy-oil/.

The solvents used include propane and the isomers of butanes and pentanes either alone or as mixtures. As the molecular weight of the solvent increases the deasphalted oil yield increases and the asphalt yield decreases [3]. However, with the higher molecular weight solvent the quality of the deasphalted oil, as measured, for example, by Conradson Carbon residue or metals content, also decreases [4]. Furthermore, the asphalt may become more difficult to handle as higher temperatures may be required to make it flow. The solvent in the deasphalted oil and in the pitch must be recovered by flash vaporization or supercritical means. The solvent is then collected, condensed and returned to the solvent tank for re-use.

Care must be taking when selecting the solvent. In particular, attention must be paid to the solvent’s auto-ignition temperature (cf. Table 1) and the temperature required to keep the asphalt flowable.

A potentially dangerous situation in the pilot plant setting can develop during a unit upset in which solvent is released above its auto-ignition point into the process area. The temperature required to make the asphalt flow depends on the feedstock processed, the solvent selected and the operating conditions. Based on these factors, Intertek PARC may recommend the use of iso-pentane over n-pentane as solvent or the use of diluents to improve the flowability of the solvent-free asphalt so that the temperature required to make the asphalt flow is well below the solvent’s auto-ignition temperature.

References:

1. Speight, J.G, and Ozum, B., Petroleum Refining Processes, Marcel Dekker, New York, 2002, pp. 572-579.

2. Gary, J.H., Handwerk, G.E, and Kaiser, M.J., Petroleum Refining: Technology and Economics, Fifth Ed., C RC Press, New York, 2007, pp.311-313.

3. Sequira, Jr. A., Lubricant Base Oil and Wax Processing, Marcel Dekker, New York, 1994, pp. 53-80.

4. Sprague, S.B., “How Solvent Selection Affects Extraction Performance”, Paper AM-86-36, presented at the 1986 NPRA Annual Meeting, Los Angeles, March 23-25, 1986.

Delayed Coking for Pretreating Vacuum Resids

2010-05-04T10:03:00.000-07:00

Delayed coking is being used to pretreat vacuum resids to prepare coker gas oil streams for catalytic cracking and hydrocracking. The coke is used in various applications, including fuel use, anode manufacture for alumina production, and electrode manufacture for steel production. In the early refineries, severe thermal cracking of heavy stocks, including vacuum residues, resulted in coke deposition in the heaters. Heating above the coking temperature is possible without significant coke formation in the furnace by heating so rapidly that little reaction occurs. This is done by operating at high velocities in high heat flux furnaces.

The heater effluent is then sent to the coke drum where it stays to undergo thermal cracking to make coke and vapors which are then condensed. In other words, the coking of the vacuum residue is delayed until it accumulates in the coke drum [1, 2]. Intertek PARC provides delayed coking services using either a small delayed coker pilot plant with a 5 liter coke drum or a large delayed coker pilot plant with three coke drums using either 29 or 81 liter liners.

For more information on Intertek PARC’s delaying coking capabilities, visit: http://www.intertek.com/testing/pilot-plant/thermal-heavy-oil/ . Intertek provides analytical services for coke and coker products analysis. For more information on coke analysis, visit: http://www.intertek.com/petroleum/testing/coke-fly-ash/.

The Petroleum Administration for Defense (PADD) 3 area consists of the following states: Texas, New Mexico, Mississippi, Louisiana, Alabama and Arkansas. 2009 Data indicates that there are 57 operable refineries in the PADD 3 Gulf Coast region. Over the last 15 years, the operable crude oil distillation capacity has increased from ~7.0 MM bbls/day to close to ~8.5 MM bbls/day. To handle the imported, heavier crudes targetted for use in these refineries, delayed coking charge capacity of PADD 3 refineries was increased from 726 M bbl/day to close to 1,350 M bbl/day from 1995 to 2009. Refinery utilization has steadily increased until 2004 when it started to decline. PADD 3 imports have also steadily increased since 1985 until 2004 when it too started to slightly decline [3].

PADD 3 refineries import crude oil from OPEC countries, including Saudi Arabia, Nigeria and Venezuela; and Non-OPEC countries, including Mexico. Developments since 2004 indicate steady declines in Mexican and Venezuelan heavy crude exports to the U.S. Furthermore, Saudi Arabia has reduced exports of high-sulfur crude oil to the U.S. [3, 4]. Mexico’s crude oils consist of a mix of a heavy crude, 22° API Maya, and lighter crudes, 34° API Isthmus and 39° API Olmeca. Most of the lighter crudes are used domestically with the bulk of the Maya being exported to PADD 3 refineries. Venezuela produces four crudes with an average API of less than 20° [3].

Consequently, as Welsch pointed out, heavy crudes are in demand in the PADD 3 region. Only 2.2% of crude refined in the PADD 3 region comes from Canada and producers of crude from Canada’s oilsands are trying to enter the PADD 3 market to take advantage of the increased heavy crude demand [4]. Pilot plant services will be required to quantify yields and product properties upon delayed coker feedstock changes.

References:

1. Gary, J.H., Handwerk, G.E., and Kaiser, M.J., Petroleum Refining: Technology and Economics, Fifth Edition, CRC Press, New York, 2007, pp. 97-105.

2. Hengstebeck, R.J., Petroleum Processing, Principles and Applications, McGraw-Hill Book Company, Inc., New York, 1959, p.136.

3. http://www.eia.doe.gov/

4. Welsch, E., Dow Jones Newswires, March 23, 2010, cited by Downstreamtoday.com.

Crude Oil Desalting and Residual Water Issues

2010-04-23T11:16:00.000-07:00

Residual water, which is dispersed in crude oil as very small droplets, typically contains substantial amounts of dissolved salts as chlorides. The salts are picked up in the reservoir or during transportation. A typical oil reservoir contains gas, oil and water with the water often being salty. The salt in crude oil can lead to higher corrosion rates, catalyst poisoning in down stream units and fouling of heat exchangers. The crude can also contain suspended solids. The crude oil is typically desalted before being sent to the distillation train. Intertek PARC has a two-stage electrical (AC) desalter which can be operated either in the co-current or counter-current mode. For more information on desalting, visit: http://www.intertek.com/testing/pilot-plant/desalting-crude-oil/.

The salt content of the desalted oil is usually reduced to a level of 1-2 lbs/1000 bbls. It can be determined using electrometric methods ASTM D 3230 and IP 265 by measuring the conductivity of the crude oil in an alcohol solvent mixture. These two tests measure the conductivity of the oil due to the presence of inorganic chlorides, such as sodium, calcium and magnesium. A calibration curve is generated relating current vs. chloride concentration. A 10: 20: 70 CaCl2: MgCl2: NaCl mixture, which presents a number of common crudes, is used in the calibration. Species other than chlorides must not contribute significantly to conductivity for accurate results to be obtained. ASTM D 3230 and IP 265 testing is provided by Intertek (http://www.intertek.com/petroleum/test-directory/s/).

Crude conductivity can be significantly impacted by blending of two or more crudes to meet total acid number (TAN) specifications, typically <0.5. Blending two low conductivity crudes can lead to a blend with conductivity higher than those of the individual crudes [1]. When desalting high conductivity crude either due to higher temperature operation or to the presence of other conducting species, more power is consumed [2]. ASTM D 3230 and IP 265 are not reliable with high conductivity crudes due to interference as pointed out in the method D 3230. Potentiometric method ASTM D 6470 or back titration method IP 77 can be used to measure chloride concentrations. ASTM D 6470 and IP 77 testing is provided by Intertek (http://www.intertek.com/petroleum/test-directory/s/).

Regards;

Rob Absil, Intertek PARC Pilot Plant Technology Center

Topics of interest include:

•   Crude oil blending effects on crude oil conductivity.
•   Problems experienced with crude salt content measurements.

References:

1.   Potter, A.C., Crude Oil Conductivity Presentation, February 2007, retrieved from Internet.
2.   Pruneda, E. F. et al., J. Mex. Chem. Soc.,2005, 49 (1), 14-19, retrieved from the Internet.