Threshhold Blistering

With a heat intensity of 2000Btu (hr)(ft2), which is six times the solar radiation, the pain threshhold is 8 sec. Therefore, if time is to be allowed for a person to run to safety, the individual should not be subjected to a heat intensity of higher than about 1500Btu (hr)(ft2) in the event of a major refinery failure (Figure 10-5(c)). A stack of sufficient height can be selected to satisfy this condition. Radiation levels used for design are Solar radiation adds to the calculated flame...

Normal And Peak Steam Demand

Normal steam demand at different pressure levels can be estimated by adding together the demand of the individual process units of the refinery. Steam demand for off-site areas is similarly estimated. To this is added the following 1. Demand of steam for major equipment, which must be steam driven. 2. The quantities of steam generated by waste heat boilers (negative demand). 3. The exhaust steam demand for heating the building and off-site areas. 4. The exhaust steam demand for atomizing fuel...

Diesel

Diesel grades have an ASTM end point of 650-700 F. Diesel fuel is a blend of light and heavy distillates and has an ASTM boiling range of approximately 350-675 F. Marine diesels are a little heavier, having an ASTM boiling end point approximately 775 F. The most important specifications of diesel fuels are cetane number, sulfur, and pour or cloud point. Cetane number is related to the burning quality of the fuel in an engine. The permissible sulfur content of diesel is being lowered worldwide...

Alternative Method For Determining The Blend Flash Point

The flash index is first determined from Table 11-17. Two empirical indices are worked out, the 154 index and the 144 index. The 154 index is a criteria for meeting the 154 F flash point and 144 index is criteria for meeting the 144 F flash point. If the value of the 154 index is positive for any component or blend, it will meet the 154 F flash criteria that is, the flash will be equal to or higher than 154 F. Similarly, if the 144 flash index is positive, it will meet the 144 F flash criteria....

Crude Oil Assays

A frequent problem encountered in process studies is the determination of the yield and properties of crude oil cuts. The usual crude assay data provide information on limited number of cuts, and in general, the desired information on specific cuts has to be obtained by some form of interpolation or approximation. Also, the property of a wide cut may not be the same as the combined properties of two adjacent narrow cuts spanning the same cut points as the wide cut. The same criticism applies to...

Partial Oxidation Process

Partial oxidation is a noncatalytic process1 for the manufacture of hydrogen from heavy feedstocks, such as vacuum resides and asphaltic pitch. The heavy feed is partially burned using oxygen in a reactor. Due to high temperature, the remaining part of the feed is cracked. The composition of the hot synthesis gas leaving the reactor is mainly CO and H2, with smaller quantities of C02, Ar, N2, CH4, and H2S along with some soot and ash. All the sulfur in the feed is converted to H2S. Argon in the...

Flue Gas Desulfurization

Flue gas desulfurization aims to reduce sulfur oxides emissions from the stack gases of the refineries and power plants to 150-1500 ppm range, for pollution control. The process is particularly useful for refineries and power plants burning high-sulfur heavy fuel oil. Table 8-5 Sulfur Plant Tail Gas Treatment Operating Conditions Table 8-5 Sulfur Plant Tail Gas Treatment Operating Conditions BASIS ACID GAS FEED RATE OF 180 MSCF HR. BASIS ACID GAS FEED RATE OF 180 MSCF HR. Table 8-6 Catalyst...

Temperature

The typical hydrocracker reactor operates between 775-825 F and 2600 psig reactor inlet pressure. The high temperatures are necessary for the catalyst to hydrocrack the feed. The high reactor pressure is Single-Stage Hydrocracker Operating Conditions Single-Stage Hydrocracker Operating Conditions MAKEUP + RECYCLE AT REACTOR INLET, SOR RECYCLE COMPRESSOR DISCHARGE PRESSURE necessary for catalyst life. Higher hydrogen partial pressure increases catalyst life. To keep the hydrogen partial pressure...

Gasoline Blending By The Interaction Coefficient Method2

In a given refinery, where the maximum number of gasoline blend components and their properties are known, it is possible to develop an accurate blending spreadsheet program, using the individual blendstock properties and the binary blend interaction coefficients. The only additional laboratory work required is the determination of the properties RON, MON, and ASTM distillation of all possible binary blends for a given number of blend components. Interaction coefficients are determined for all...

Operating Modes And Yields

This information is available from refinery's stock balancing manual. This information is developed from crude oil assay and refinery test runs on the units. If no information is available, distillation yields can be estimated from crude assay and ASTM distillation of the cuts. The process yields of secondary units such as cat reformers, FCCU, visbreakers, and hydrocracker units are available from the latest refinery test runs or the process licensor data. From whatever source the yield data is...

Example 113

Calculate the IBP and 10-90 points of a blend of FCC naphtha (50 volume), coker naphtha (16 volume), and cat reformate (34 volume) with the following ASTM distillation The IBP of the blend, is calculated as follows. Assume that the IBP repre sents 1.4 distilled instead of 0 and modify the preceding data as follows Now draw the ASTM distillation curves with percent distilled on the X- axis and distillation temperature on Y-axis. Read off the temperature at which 1.4 volume is distilled off....

Coker Run Length

The run length between decoking while processing heavier, high Con-radson carbon feed stocks is an important variable. Run length is affected by feedstock quality and operating conditions. Although it is not possible to predict a run length, values generally encountered are between 9 and 12 months for a maximum radiant heat flux of 10,000 to 12,000 Btu (hr)(ft2) and feed cold velocities in the tube of around 6 ft sec. Multiple injections of steam are used to adjust coil residence time and...

Sulfitic Brine Treatment

Sulfitic brine is partly decomposed back into NH3, S02, and H20 in an evaporator according to the preceding equations. The bottom liquid containing the bulk of sulfates is fed to a sulfate reduction reactor, where sulfates, thiosulfates, and remaining sulfites are reduced to S02, NH3, and H20 by reaction with molten sulfur 2NH4HSO4 + S 3S02 + 2NH3 + 2H20 (NH4)2S203 S02 + S + 2NH3 + H2O This reaction takes place in a liquid bath at a temperature of approximately 660 F, using a molten salt bath....

Twostage Operation

Hydrocracker Reactor

In the two-stage scheme, the unconverted material from the first stage becomes feed to a second hydrocracker unit. In this case, the feed is already purified by the removal of sulfur, nitrogen, and other impurities and the second-stage can convert a larger percentage of feed with better product quality. A heavy gas oil feed contains some very high-boiling aromatic molecules. These are difficult to crack and, in feed recycling operation, tend to concentrate in the recycle itself. High...

ASTM Specification D86 Distillation 50 and 99 Temperatures from TBP Temperatures F

Calculate factors A and B as follows Calculate the 50 ASTM boiling point as follows D 0.735 x A - 3.765 (if 50 GE A BUT LT 220) D 0.027 x A + 6.555 (if A.GE. 220) 2. Calculate the uncorrected D-86 50 boiling point ASTM50 TBP50 - D Calculate the 99 ASTM boiling point as follows D 0.00398 x B2 - 0.556 x B (if B.LT. 90) D -74.914 + 12.672 x ln( ) (if B.GE. 90) 2. Calculate the uncorrected D-86 Now correct the D-86 points using stem correction, if temperature greater than 274 F. (Note the iterative...

Resid Processing In The Fccu

It is possible to process resid feed in the FCCU in place of vacuum gas oil. The resid feed is no less crackable than vacuum gas oil. Paraffinic resid crack easily yields higher-valued products, while aromatic feeds is difficult to crack. Increasing the aromatic resid level in the feed increases coke and dry gas yields and decreases overall conversion and gasoline yield. However, the metals nickel and vanadium and Conradson Con carbon of the resid from most crudes make processing of resid in...

Batch Blending

In batch blending, the components of a product are added together in a tank, one by one or in partial combination see Figure 10-2 . The materials are then mixed until a homogenous product is obtained. Estimation of Product Tankage Requirements 'OPERATIONAL REQUIREMENTS EQUIVALENT TO 20 DAYS PRODUCTION. CORRESPONDING TO REFINERY CRUDE THROUGHPUT OF ISO MBPSD. 3MAXIMUM PARCEL SIZE DEPENDENT ON TANKER SIZE FOR PRODUCT LIFTING, CAPACITIES OF SHIPPING TANKS, AND LOADING RATES OF THE TERMINAL. FIXED...

Edmisters Method

ASTM distillation is converted to the true boiling point TBP distillation using Edmister's correlation. The blend TBP can be determined simply by adding together the volumes contributed by all the components at a chosen temperature, dividing by the total volume, and plotting a temperature vs. percent distillation chart. The TBP distillation vs. temperature graph can be converted back into ASTM distillation again, by using Edmister's correlation in the reverse. This procedure is not very...

Pour Point Blending

The pour point and freeze point of the distillate kerosene, diesels, etc. do not blend linearly, and blending indices are used for linear blending by volume. Tables 11-14 and 11-15 show the blending indices used to estimate the pour point and cloud point of distillate petroleum products. A blending margin of 10 PI pour index is allowed between the guaranteed specification and the refinery blending. For example, to guarantee a pour spec of 6 C 21.2 F, pour index 336.3 , the blending target would...

Space Velocity

Because alkylation occurs almost instantaneously, the residence time of reactants is not a limiting parameter. The space velocity SV in this case may be defined as follows olefin in contactor bbl hr acid in contactor bbl The term is simply a measure of the concentration of olefins in the acid phase of the reactor. As the olefin space velocity increases, octane tends to decrease and acid consumption tends to increase. The minimum acid strength required to operate the system is 85-87wt , although...

Flash Point Blending

The flash point of a blend can be estimated from the flash point of the blend components using flash point blend indices, which blend linearly Table 11-14 Pour Point of Distillate Blends Table 11-14 Pour Point of Distillate Blends also applicable to freeze points and fluidity blending is on a volume basis. POUR POINT BLEND INDEX 3262000 x POUR POINT, R 1000 125 POUR POINT, R 1000 x Index 316000 08 POUR POINT, F POUR POINT R - 460 also applicable to freeze points and fluidity blending is on a...

Saturation Of Aromatics

Some of the aromatics in the feed are saturated, forming naphthenes. Saturation of aromatics accounts for a significant proportion of both the hydrogen consumption and the total heat of reaction. The heat of reaction varies from 40 to 80 Btu scf of hydrogen consumed, depending on the type of aromatics being saturated. In general, higher reactor pressure and lower temperature result in a greater degree of aromatic saturation H-OIL is a commercial processed for resid hydrocracking resid...

Example 114

Determine the amount of cutter stock need to blend vacuum resid with a kinematic viscosity of 80,000 est at 122 F to finished fuel oil with viscosity of 180 centistokes at 122 F. The cutter stock viscosity is 8.0 est. To estimate the cutter requirements, determine the viscosity blend indices for vacuum residuum, cutter stock and finished fuel oil from the viscosity blend indices table and blend these values linearly. We see from the table on page 330 that 42.7 cutter stock is required to reduce...

Partial Inline Blending

Partial in-line blending is accomplished by adding together product components simultaneously in a pipeline at approximately the desired ratio without necessarily obtaining a finished specification product see Figure 10-3 . Final adjustments and additions are required, based on laboratory tests, to obtain the specification product. In partial in-line blending, the mixing is required only for final adjustment. Additives, if any, such as dye for gasoline, are added as a batch into the blending...

Effluent Treatment

The liquid phase from the contactor tube bundle is collected on the suction trap side of suction trap flash drum V-010. This stream contains traces of acid and neutral esters formed by the reaction of sulfuric acid with olefins. The esters are corrosive and must be removed to prevent corrosion in the downstream equipment. These esters are removed in the effluent treating section by washing the stream with fresh sulfuric acid followed by washing with a dilute alkaline water stream. The net...

Cooling Towers

The cooling towers function by direct removal of heat from water by air flow and vaporizing a portion of water. Both forms of cooling are accomplished by a counterflow of air and water. The towers are constructed of wood, metal, or concrete with wood or plastic packing for distribution of the water flow. A portion of water passing over the cooling tower is vaporized. Any solid this water contains is left behind and increases the concentration of solids in water. To limit the concentration of...

Conversion to Saybolt Furol Viscosity

Kinematic viscosity in centistokes mm2 sec at 50 and 98.9 C can be converted to Saybolt furol viscosity in Saybolt furol seconds SFS units at the same temperature by API databook18 procedure SFS98.9 0.4792 x VIS98.9 - 2 , 11-9 SFS50 Saybolt furol viscosity at 50 C, Saybolt furol seconds VIS50 kinematic viscosity at 50 C, centistokes mm2 sec SFS98.9 Saybolt furol viscosity at 98.9 C, Saybolt furol seconds VIS98.9 kinematic viscosity at 98.9 C, centistokes mm2 sec .

Example 101

A coastal refinery processes 180,000 barrels per day of 30.6 API Middle Eastern crude. The capacity of various processing units in mbpd and tonnes day are shown in Table 10-4. Figure 10-1 shows the overall material balance and product blending schedule of the refinery. Table 10-2 shows the rundown temperatures of base stocks and blended products. Table 10-5 shows the facilities available at the refinery marine terminal. Table 10-1 shows the historic for the distribution of tanker fleet arriving...

Refinery Flare System

Flaring is used as an effective and safe method of hydrocarbon vapor disposal whenever excess hydrocarbons must be controlled due to equipment failure or major emergencies, such as instrument malfunction, power failure, or plant fire. Before the utilization of flares, the gaseous waste streams were vented directly to atmosphere. This created two problems. The first is personnel and neighborhood safety. There was always the possibility of combustible vapor reaching the ground in sufficient...

Product Specifications

All streams from different processing units are blended to produce saleable finished products at certain specifications. The major product groups are naphtha, gasoline, kerosene, diesel, and fuel oil. However, each product group may have a large number of product grades to meet the requirements of the product in different regions of the world. For example, a refinery may produce 10 or more grades of diesel with different pour points, sulfur, cetane indices, and the like to meet its client...

Fired Or Endothermic Flares

Fired or endothermic flares are used for low heat waste streams, such as sulfur plant tail gas, ammonia vapor, and the like. Whenever the heat content of waste gas is below 150Btu ft3, then a fired flare with high energy assist gas is required for complete combustion. Certain gases, like ammonia, though having a relatively high calorific value of 365 Btu ft3, still require assist gas to increase the heat content and ensure complete combustion while minimizing N02 production. This is because the...

Determination Of Narrow Cut Pseudocomponent Properties

The vol of each narrow cut or pseudocomponent is known from TBP curve of the crude, once the cut points of pseudocomponents are defined. If their properties can be determined, these can be combined to determine the yield and properties of any other wide cut of that crude not available in the crude assay data. Also, narrow cut properties from different crudes can be combined to predict the wide cut yields and the properties from mixed crudes. Narrow cut properties are determined from the wide...

Refinery Fuel Gas System

Lpg Distillation

The refinery fuel gas system is designed to supply fuel gas to steam boilers, process furnaces, gas engines, and gas turbines at a regulated pressure and reasonably constant heating value. The system includes mixing drum controls and distribution piping. Wherever necessary, a stand by storage of liquefied petroleum gas LPG is included. A typical refinery fuel gas system is shown in Figure 10-10. The mixing gas drum is typically operated at 30 to 40 psig, which allows for delivery of gas at...

Vapor Lock Protection Temperature

When the volatility of gasoline is too high or when high temperatures or low pressure conditions prevail, bubbles of vapor can form at critical points in the fuel systems. This prevents adequate supply of fuel to the engine by preventing the fuel pump from operating because of low or negative suction pressure. Vapor lock has a number of unwelcome effects, such as difficulty restarting a hot engine, uneven running, and reduced power output at high speed. Vapor lock is influenced by the...

Aniline Point Blending

The aniline point is of a gas oil indicative of the aromatic content of the gas oil. The aromatic hydrocarbon exhibits the lowest and paraffins the highest values. Aniline point AP blending is not linear, and therefore blending indices are used. The following function converts aniline point to the aniline index where ANLIND is the aniline index and AP is the aniline point. The aniline index can be converted back into the aniline point by the following function AP 200 x SQRT 1.5625 AN fD - 1.25

Reformer Feed and Product Properties Propertyunits

FEED HYDROTREATED HEAVY NAPHTHA, TBP 194-284 F SPECIFIC GRAVITY 0.734 REFORMATE IBP INITIAL BOILING POINT EP END POINT FBP FINAL BOILING POINT RVP REID VAPOR PRESSURE. is achieved at high temperatures in contact with powdered catalyst without the use of hydrogen. After separation of the catalyst, the hydrocarbons are separated into the desired products by fractionation. The main products of the FCC process are gasoline, distillate fuel oil, and olefinic C3 C4 liquefied petroleum gas LPG ....

Refinery Steam System

Roughly 10 of the crude throughput of the refinery ends up as refinery fuel. Steam generation alone accounts for about one third of the refinery total fuel consumption. The generation and distribution of steam and electrical power constitute a major part of a refinery's utility system. There are three broad categories of usage of steam in the refineries 1. Heating loads. These are usually well defined. Included in this category is steam for heat exchangers, reboilers, steam tracings, and...

Refinery Material Balance Spreadsheet Program

To run the program the following data in the spreadsheet are updated. 1. Time period or number of days in the month. 3. Total crude rate to each crude distillation unit, in thousands of barrels per day. 4. Operation mode of each crude and vacuum column. 5. Unit capacities available for each crude and vacuum column. 6. Disposition of atmospheric resids to various vacuum distillation columns. The distribution of various crudes to crude distillation units CDUs and their operation mode is decided...

Continuous Inline Blending

In continuous in-line blending, all components of a product and all additives are blended in a pipeline simultaneously, with such accuracy that, at any given moment, the finished specification product may be obtained directly from the line see Figure 10-4 . As a result of the accuracy and safeguards included in the system, no provision is necessary for reblending or correction of blends. Each base stock component is stored in two tanks. Samples of the component are test blended in the plant...

Gasoline Octane Blending

The research RON and motor MON octane numbers of a gasoline blend can be estimated using the following equations 1 R i Ci x R2 - Ri x Jx C2 x Oj - 02 C3 Ai - A2 R research octane numbers of blend R0 research octane number of each component Ri volume average of octane number 2 volume average of product of R0 and J 01 volume average of squared olefin content 02 square of volume average olefin content A volume average of squared aromatic content square of volume average aromatic content.

Conversion to Saybolt Universal Viscosity

Kinematic viscosity in centistokes mm2 sec can be converted to Saybolt universal viscosity in Saybolt universal seconds SUS units at the same temperature by API databook16 procedure or using ASTM conversion tables 17 3930.2 262.7 x est 23.97 x est 2 1.646 x est 3 x lO 5 SUS Saybolt universal viscosity in Saybolt universal seconds units at 37.8 C est kinematic viscosity, centistokes mm2 sec . SUS viscosity at 37.8 C can be converted to SUS viscosity at another temperature by following...

Luminometer Number Blending

Luminometer numbers do not blend linearly. Therefore, blending indices are employed that blend linearly by weight. The procedure is to first determine component Luminometer blending indices, blend component indices on weight basis to obtain blended index, next calculate stream Luminometer number from following relations. Li exp exp 139.5 - L 128.448 where Li luminometer number blending index The cetane index CI is estimated from the API gravity and 50 ASTM distillation temperature in F of the...

Process Water

Three uses are made of process water in the ARDS unit. Water is used to increase the activity of the catalyst and prevent the deposit of solids in the reactor effluent cooler. Water is also used to wash recycled gas before and after the amine wash. Water used to increase catalyst activity is added to the resid charge upstream of the charge heater and called injection water. Deaerated condensate, stored under an inert gas blanket, is used for this purpose. The function of the fractionation...

Fluidity Of Residual Fuel Oils

The low temperature flow properties of a waxy fuel oil14 depend on its handling and storage conditions. These properties may not be truly indicated by the pour point. The pour point of residual fuel oils are influenced by the previous thermal history of the oil. A loosely knit wax structure built up on cooling of oil can normally be broken by the application of relatively little pressure. The usefulness of pour point test in relation to residual fuel oils is open to question, and the tendency...

Treatment Of Sanitary Sewage

All sanitary sewage in the refinery is collected in a common sewage lift station, from which it is pumped to equalization tank TK-101 see Figure 9-8 . The sewage equalization tank is sized for approximately 6hr retention of normal flows plus capacity to accommodate surges associated with peak flows from the lift station. The equalization tank is aerated to prevent the sanitary wastewater from becoming septic. The sewage is treated in two aeration tanks TK-103, with each unit having the capacity...

Emissivity

Lf FLAME LENGTH C FLAME CENTER H STACK HEIGHT Lf FLAME LENGTH C FLAME CENTER H STACK HEIGHT Figure 10-5. Thermal radiation from elevated flares. Figure 10-5. Thermal radiation from elevated flares. and the coordinates of the flame center located at L 3 , with respect to the flare tip, are The distance from any point on the ground level to the center of the flame is These equation allow you to determine the radiation intensity over any location. The worst position for a given gas flow and wind...

Table 423 MTBE Operating Conditions

REACTOR TEMPERATURE F 175 SPACE VELOCITY, LHSV hr1 4.9 CATALYTIC COLUMN COLUMN TOP TEMPERATURE F 145 COLUMN TOP PRESSURE psig 100 REFLUX DRUM PRESSURE psig 97 COLUMN BOTTOM TEMPERATURE F 276 COLUMN BOTTOM PRESSURE psig 114 NUMBER OF PLATES 40 C4 FEED WASH COLUMN COLUMN TOP PRESSURE psig 169 COLUMN TEMPERATURE F 104 NUMBER OF PLATES 20 RAFFINATE WASH COLUMN COLUMN TOP TEMPERATURE F 104 COLUMN TOP PRESSURE psig 202 COLUMN BOTTOM TEMPERATURE F 104 COLUMN BOTTOM PRESSURE psig 216 COLUMN TOP...

Refinery Fuel Oil System

Refinery Fuel Oil System

The purpose of refinery fuel oil system is to ensure a constant, regular supply of oil to burners of steam boilers and to process furnaces. The system includes facilities for storage, pumping, heating, and distribution of oil at suitable pressure and viscosities so that the atomization and burning of oil is possible. A typical refinery home fuel system is shown in Figure 10-9. The aim of the fuel oil system design is that operational changes to one furnace will not cause fluctuation of supply...

Crude Storage

From the viewpoint of operational safety, a refinery located close to an oilfield or pipeline terminal requires a minimum inventory equivalent to 16hr throughput. This includes a 4-hr allowance for settling, sampling, and testing. The total minimum operating inventory comprises the following elements crude oil working stock 16hr crude throughput , unavailable tank heels of all crude tanks in operation , and line content. In practice, a storage capacity equivalent to 48 hr crude throughput is...

Blending Algorithm

A study of the gasoline blending data has shown that nonlinear gasoline blending behavior can be described by an equation of the following type CALC VOL 1,2 XX, X X2 1,3 1 X 8,9 X X8 X X9 calc calculated property Pvol volumetric weighted average property i,2 8,9 the component interaction coefficients Xi Xg volume fraction of each component. The interaction coefficient for a binary blend can be calculated as follows I A B PACTUAL PvOL 11-4 BLEND MON 90.72 COLUMNS ARE IN PARENTHESES 3 MOTOR...

Smokeless Flare

Smokeless flaring is based on the principle of increasing the burning rate by the injection of steam into a flame, creation of turbulence in the Table 10-7 Ambient Air Quality Standards PARAMETER TYPICAL REFINERY STANDARDS U.S. STANDARDS 0.03 ppm ANNUAL ARITHMETIC MEAN 0.14ppm MAX 24-hr CONCENTRATION 0.075 mg m3 ANNUAL ARITHMETIC MEAN 0.286 mg m3 24-hr CONCENTRATION ONCE yr 9 ppm 8-hr AVERAGE CONCENTRATION ONCE yr ONCE yr 0.08 ppm, 1-hr TOTAL yr 0.05 ppm, ANNUAL ARITHMETIC MEAN 0.25 ppm MAX,...

Ground Flares

Flare Water Seal

Enclosed ground flares conceal the flame and provide smokeless operation without steam injection. By eliminating steam, one source of noise is completely removed. Combustion noise is also reduced by using many small burners and many small individual flames. The combustor is lined with an acoustically absorbent high-temperature ceramics to reduce the combustion noise. The combustion air inlet is acoustically shrouded and baffled to reduce noise outside the unit. The main disadvantages of ground...

Steam Generation And Distribution

Steam System Refinery

Steam for refinery use can be generated from one or more of these following sources fired steam or unfired steam generators, turbine exhaust or extraction. Figure 10-7 shows the general design principles for establishing refinery steam systems. The steam system consists of steam generators and a distribution network at different pressure levels for process and utility requirements. The feed is a mixture of condensate and de-mineralized water which is deaerated before being fed to the boilers....

Refinery Tankage

Tanks are required in refineries for storage of crude, blend stocks, and products for shipping. Tanks are also required as charge tanks for many secondary processing units. In a refinery, the cost of tanks alone roughly equals that of all the process units in it. From an operational point of view, refinery tankage can be divided into the following categories crude storage tanks, charge tanks for secondary processing units, base stock or component storage tanks for product blending, and shipping...

Fuel selection

Fuel gas and residual fuel are the most commonly used fuels in the refinery. Other refinery products of low monetary value, such as heavy pitch residues, visbreaker tars, FCCU decanted oil, vacuum tower bottoms from certain crudes, lube extracts, and waxes are also used as fuel in the refinery itself. The majority of these materials would be difficult to blend in a commercial fuel of acceptable specifications because of high viscosity, chemical aggressiveness, high contaminant level sulfur,...

Flare System Design

The flare system is designed to provide safe receipt and disposal of combustible, toxic gases and vapors released from process equipment during normal operation and during upset conditions. The safe disposal is achieved by knocking down the heavy ends and condensables in the flare knockout drum and burning the gases through an elevated stack. A controlled amount of steam is used to ensure smokeless burning and easy dispersion of combustion products. The process helps maintain an acceptable...

The Catalytic Distillation Section

Isobutylene final conversion is achieved in a catalytic column V-006, where the reaction and distillation are simultaneous. This column includes a fractionating tower yielding MTBE product at the bottom and unconverted C4 raffinate methanol azeotrope at top. Additional conversion is made possible by enhanced contact between reactants in a number of packed beds. In addition to packed beds, the column is equipped with approximately 40 trays for distillation. The main reactor effluent is preheated...

Operating Parameter

REACTOR INLET TEMPERATURE REACTOR AT REACTOR INLET PRESSURE H2 PARTIAL PRESSURE REACTOR PRESSURE DROP LHSV RECYCLED GAS FEED RATIO QUENCH GAS FEED RATIO H2 CHEMICAL CONSUMPTION DESULFURIZATION DENITRIFICATION 645 55 2280 1728 34.5 1.42 4575 5065 971 422.3 98.9 73.9 Gas Oil HDS Feed and Product Properties Gas Oil HDS Feed and Product Properties IBP INITIAL BOILING POINT EP END POINT. IBP INITIAL BOILING POINT EP END POINT. Table 2-14 Utility Consumption per Tons Feed Table 2-14 Utility...

Solvent System

The solvent evaporated in the LP flash tower is condensed and flows to the LP solvent receiver. Solvent from the asphalt flash tower, which operates at the same pressure, is condensed in a separate condenser and flows to LP solvent receiver. The reason for segregating the two solvent streams is the potential for the accidental fouling by asphalt carried over from the flash tower. Vapor overhead from the two strippers is cooled, and most of the water is condensed and recovered in stripper...

The Tail Gas Treatment Process

Tail Gas Treating Process

The acid gas is introduced in reactor R-101 near the bottom see Figure 8-2 . The reactor, where gas liquid contact is effected, is a packed column designed for a low pressure drop while ensuring the interfacial area Figure 8-2. Claus tail gas treatment unit. Figure 8-2. Claus tail gas treatment unit. necessary for the desired conversion. The packing volume is divided into a number of beds separated by liquid redistributors and packing support plates to ensure maximum packing efficiency all...

Needle Coke

Needle coke is used in the manufacture of large diameter 24-28 in. graphite rods for ultra high-power furnace electrodes. The material used must be of high density, low resistivity, high strength, and very low coefficient of thermal expansion CTE . This material is produced from aromatic feedstocks to the coker unit. Also, the feed must be very low in sulfur, metals, and asphaltenes. Refinery-derived feedstocks such as thermal tars, decant or slurry oil from catalytic cracking, and extracts...

Knockout Drum

A knockout drum in a flare system is used to prevent the hazards associated with burning liquid droplets escaping from flare stack. Therefore, the drum must be of sufficient diameter to effect the desired liquid vapor separation. The drum diameter can be obtained from the following empirical relation for a horizontal knockout drum to separate drops of up to 400 micron particle size T temperature of vapor, Rankine This equation is applicable to a single-flow knockout drum. Split-flow drums,...

Refinery Tankage Estimation

Hsr Naphtha Product Gasoline

For estimating the tankage requirements for a refinery, the following information is required 1. Refinery process unit capacities, in tons and barrels per day. 2. Refinery material balance and product blending schedule. Figure 10-1 . 3. Rundown temperature of all streams flowing to the base stock and shipping tanks Table 10-2 to determine product density. 4. Information on the refinery marine terminal product loading facilities that is, the available sea lines, product pumping rates, and...

Neutralization

The neutralization system is designed to collect the acid and caustic regeneration waste prior to discharge to the sea or another outlet. Facilities are provided to add acid and caustic to produce a neutral wastewater stream. The neutralization basin has two separate chambers, each designed to hold regeneration waste from three regenerations of cation exchangers, three regenerations of anion exchangers, and one regeneration of condensate polisher. Also used in neutralization are a 98 sulfuric...

Product Blending System

The process units produce various product components and base stocks, which must be combined or blended, sometimes with suitable additives, to manufacture finished products. These finished products are generally grouped into the broad categories of gasoline, kerosene, diesel and fuel oil, and so forth. Different methods of product blending are used to suit variation in the type of product, available components, operating procedures, shipping and marketing requirements, and available storage...

Cooling Water System

Refining operations are conducted at elevated temperatures. In a rough overall sense, a refinery must be in heat balance. All heat added in the forms of fuel burned, steam consumed, or coke burned must be removed by one of the various cooling systems. Water cooling is one such system. The others are air cooling and heat exchange with other streams. Cooling accounts for about 90 of the total refinery water requirements. Approximate cooling water requirements of a refinery can be estimated as a...

Table 812

Boiler Feed Water Bfw

Flue Gas Desulfurization Operating Conditions OPERATING VARIABLE UNITS SOLVENT POLYETYLENE GLYCOL , FOR SULFUR CONVERSION REACTOR 68 F, gm liter 2-10 248 F, gm liter 27 248 F, gm liter 35 S03 CONVERSION REACTOR CO-MO ON Utility Consumption, per Tons Sulfur Recovered Utility Consumption, per Tons Sulfur Recovered Table 8-14 Feed and Product Properties Table 8-14 Feed and Product Properties prevent condensation of gas, which results in foaming in the absorber or hydrocarbon contamination of the...

Acid Gas Removal

Carbon dioxide and H2S are next removed from the synthesis gas by absorption in a variety of solvents such as MEA solution, cooled metha- nol Rectisol process ,4 or potassium carbonate solution Benfield process .5 The process removes essentially all H2S and C02 from the synthesis gas and delivers a mixture of H2S and C02 to the Claus unit, recovering about 95-97 of the sulfur contained in the feedstock as saleable sulfur.

The Deasphalting Process Extraction Section

Fresh feed vacuum residue is pumped into the solvent deasphalting unit and combined with a small quantity of predilution solvent to reduce its viscosity see Figure 6-6 . The combined vacuum residue and predilution solvent at the desired extraction temperature flow into the middle of rotating disk contactor RDC V-101. Solvent streams from HP and LP solvent receivers V-106 and V-107 are combined, and a portion of the combined stream is used as predilution solvent. The major portion of the solvent...

Sour Water Stripping Unit

Battery Limit

Ammoniacal water streams from various refinery units are mixed and cooled with cooling water in E-101 to approximately 120 F see Figure 9-9 . The cooled effluent is degassed in V-101. The gases evolved are sent to flare. The degassed foul water is pumped by P-101 to tank TK-101 and kept under fuel gas blanket. Sufficient detention time is allowed in this tank to separate out traces of oil in the water. Separated oil is skimmed off with a swing arm suction line and sent to the slop oil system....

Water And Polysulfide Injection

Condensate is injected into the reactor effluent just upstream of effluent air cooler. The function of the injection water is to remove ammonia and some H2S from the effluent. The effluent temperature at the injection point is controlled to prevent total vaporization of the injected water and preclude deposition of solid ammonium bisulfide. Trace amounts of cyanide ion in the reactor effluent contribute to corrosion in the effluent air cooler. A corrosion inhibitor such as sodium polysulfide is...

Base Stock Tanks

Product received from any single unit of the refinery may not necessarily be a finished product. It can be feedstock for another processing unit or a blend stock for a product or group of products. For example, reformate from the cat reformer unit may be a base or blend stock for all the gasoline grades being produced by the refinery. If a tank is utilized to store an intermediate stock from a refinery unit for product blending, it is called a base stock tank. In refineries with a continuous...

Hydrogen Recovery

The objective of hydrogen recovery unit see Figure 5-5 is to recover hydrogen from hydrogen-rich off gases released from several units in a refinery for example, the hydrocracker, various desulfurizing units naphtha, kerosene, diesel, and fuel oil , or the cat reformer. Hydrogen-rich gas recovered in a hydrogen recovery unit HRU is gathered into a hydrogen header together with hydrogen gas manufactured by the hydrogen production unit to supply makeup hydrogen to several hydrogen-consuming...

Sea Water Cooling System

Seawater Cooling System

A typical direct sea water cooling system is shown in Figure 9-2. Because of the large volume of water intake for cooling, water is pumped from the sea to an inlet sump through a battery of low lift pumps. Sea water next flows through a system of bar screens, scrapper screens, and rotary screens to the suction of the high lift pump manifold. The screen system prevents entry of marine life, seaweed, algae, and the like into pump suction. To prevent growth of algae and fungi and suppress...

Table 54 Methanator Reactor

EFFLUENT FROM METHANATOR F REACTOR DRY GAS INLET SPACE VELOCITY hr1 REACTOR FEED AND EFFLUENT REACTOR CATALYST FORM Dimensions Composition, Ni 4.50 0.00 0.00 91.82 3.69 0.00 100.00 0.015 lt 0.45 ppm lt 9.55 ppm shift converter is cooled to 430 F by raising steam in E-105 and preheating the methanator feed in E-106 and boiler feed water before it enters the low-temperature CO converter R-104 at approximately 400 F. In this reactor, most of the remaining carbon monoxide is converted to C02 over a...

Sour Water Treatment

Water Treatment Plant Steam Stripping

Sour water, rich in NH3 and H2S content, is produced from refinery crude distillation units, hydrocracker, hydrodesulfurization units, gas handling, amine regenerators, delayed cokers, sulfur plant tail gas treating units, and the like. Sour water is produced by the steam stripping operation during crude distillation hydrotreating and hydrocracking operations. During most hydrocracking and hydrotreating operations, NH3 and H2S Sanitary Sewage Treatment Aeration Unit Operating Conditions...

Table 816

Amine Treatment Unit Operating Conditions OPERATING VARIABLE UNITS INCOMING LEAN DIETHANOL AMINE F 150 TEMPERATURE INCOMING SOUR GAS TEMPERATURE F 140 ABSORBER BOTTOM PRESSURE psig 27 NUMBER OF PLATES IN ABSORBER 24 HIGH-PRESSURE AMINE ABSORBER INCOMING LEAN DEA TEMPERATURE F 150 INCOMING SOUR GAS TEMPERATURE F 140 RICH AMINE LOADING MOLES H2S 0.35-0.45 ABSORBER BOTTOM PRESSURE psig 2410 REGENERATOR COLUMN TOP F 220 TEMPERATURE REGENERATOR COLUMN TOP PRESSURE psig 13 REFLUX DRUM TEMPERATURE F...

Feed and Product Properties Natural Gas Feed

H2s Absorber Column

METHANE amp NITROGEN REMAINDER with Benfield solution flowing from the top of the column. C02 is removed from the gas stream by a solution of potassium carbonate, promoted by DEA and containing a vanadate corrosion inhibitor approximately 25.7 potassium carbonate and 4.76 diethanol amine . Part of the potassium carbonate is converted to bicarbonate on each pass. Since the cooler solution has a lower carbon dioxide vapor pressure, the top part of the C02 absorber is provided with a cooled stream...

Boiler Feedwater System

Demin Water System

Municipal water feed to the refinery must be upgraded to boiler feed-water quality by further treatment see Figure 9-3 . Boiler feedwater is used as makeup to fired and nonfired steam generators located in the utility plants and process units. Boiler feedwater is also used for process purposes. Fresh water, as received from an outside supply, may not have enough pressure to fill tank TK-101. Booster pump P-101 is used to elevate the water supply pressure. Feedwater is stored in tank TK-101,...

Treatment Of Oily Water

Thickened Sludge Sump Plan

Water from desalters is cooled from 225 F to approximately 130 F in exchanger E-101 to prevent thermal damage to CPI oil water separator plates see Figure 9-6 . The cool effluent next joins all other potentially contaminated water streams for removal of oil in CPI-type API separators CPI-101A and CPI-10IB. CPI separators remove most of the free oil and some of the settleable solids associated with influent streams Table 9-6 . They do not reduce emulsified oil, H2S, or NH3. Oil removed from the...

Crude Desalting

Crude desalting is the first processing step in a refinery see Figure 1-6 . The objectives of crude desalting are the removal of salts and solids and the formation water from unrefined crude oil before the crude is introduced in the crude distillation unit of the refinery. Salt in the crude oil is in the form of dissolved or suspended salt crystals in water emulsified with the crude oil. The basic process of desalting is to wash the salt from crude oil with water. Problems occur in efficient...

Wet Slop Oil System

LP low pressure. Figure 9-7. Wet slop system. LP low pressure. facilitate the breaking up of oil water emulsions, an emulsion-breaking chemical is added to the wet slop oil during pump mix cycle. The water-free slop oil is pumped to a dry slop oil tank. The oil-free water is drained to oily water sewer and returned to the CPI system. The entire operation, consisting of collection, heating, and transfer, is a manual batch type operation.

Feed Gas Treatment

Homofermentation Reaction

The feed gas coming from various desulfurization and hydrocracking units purge gases, stripper off gases, etc. usually contain a high volume percentage of H2S 2.9 vol max, which must be brought down to less than 50 ppmv to prepare the feed for the PSA unit. The feed gas is first fed to feed gas knockout drum V-102, at 240psig, where any condensed liquid is separated out. The hydrogen sulfide is next removed by scrubbing with ADIP solution in Adip absorber column V-101. The ADIP solution is a...

Olefin Hydrogenation

The hydrogenation of olefins is one of the most rapid reaction taking place, and therefore almost all olefins are saturated. The heat of reaction is about 140 Btu scf of hydrogen consumed. Olefin content is generally small for straight-run products, but for stocks derived from secondary thermal processes such as coking, visbreaking, or resid hydrocracking H-OIL etc. , it can contribute a considerable amount of heat liberated in the hydrocracker reactor.

The Claus Sulfur Recovery Process

Sulphur Recovery Claus

Acid gas from upstream treating units is mixed with a controlled amount of air and burned in combustion reaction furnace H-01 see Figure 8-1 . The gaseous product emerges from the furnace at 2500 F and passes through waste heat boiler B-01, producing HP steam at 900 psig. After leaving the boiler, the sulfur-laden gas enters first condenser E-01, where sulfur is condensed and collected in a sulfur sump. The gas leaving the first condenser is reheated by a burning fuel gas to the reaction...

Refinery Wastewater Treatment

Refinery Waste Water

During the processing of oil in the refinery, large volumes of water flow through the processing units in the form of cooling water, process water, steam, equipment washings, unit hydrotests, and the like and these streams pick up small quantities of hydrocarbons or oil from equipment and spillage. Oil-contaminated storm water flows from the curbed areas of the refinery add to this load. The objective of the treatment is to separate oil from the wastewater before this water is allowed to be...

Claus Tail Gas Treatment

Sulfur recovery in a conventional Claus sulfur unit depends on the number of catalytic stages in the unit. An average Claus plant with three catalytic stages may recover approximately 95-97 of the sulfur contained in the acid gas fed to the unit, letting off as much as 3-5 of sulfur in the air in the form of stack gases after incineration. With increasing concern for environmental air quality, this practice is becoming unacceptable. Tail gas treatment removes most of the sulfur contained in the...

H2s s02 3s 2h20

The reaction of S02 and H2S also occur in the thermal stage at 2500 F by burning one third of H2S to S02 to obtain H2S S02 stoichiometric ratio of 2 to 1. At high temperature, conversion up to 70 into sulfur may be reached for the Claus reaction. In the presence of inerts mainly C02 in the feed, lower conversion values are obtained. To increase sulfur recovery, outlet gases from thermal stage are cooled down To condense and remove most of the sulfur, thus shifting the equilibrium of Claus...

Process Description

Boiler With Thermosyphon Claus Sulphur

The stack gases of the refinery are scrubbed with an aqueous solution of ammonia in column C-101 see Figure 8-3 . The ammonia solution is introduced into the column at the top, while flue gases enter the column near the bottom. The rich effluent containing dissolved sulfur oxides, called sulfitic brine, enters tank TK-101, where any dust contained in the stack gases is separated out by settling. The sulfitic brine is pumped by P-101 to heat exchanger E-101, heated by medium-pressure steam, and...

Feed Quality

Typically, the feed to a cat reformer unit for gasoline production is a heavy straight-run naphtha with an initial boiling point IBP of 194 F and final boiling point FBP of 284 F. Benzene is an undesirable component in the gasoline because of environmental pollution concerns. It is therefore important to minimize or exclude any benzene precursors in the cat reformer feed by keeping the feed IBP higher than 180 F. The cat reformer feed is hydrotreated in a naphtha hydrotreater unit to remove any...

Visbreaking

Visbreaking is a mild thermal cracking process.4 The function of a visbreaking unit is to produce lower viscosity and low-pour resid for blending to fuel oil. In this cracking process, cracked gas, gasoline naphtha, gas oil, and thermal tar are produced. The gas oil is blended back into the thermal tar to yield fuel oil. Thermal cracking reduces the viscosity and pour point of the resid and hence the cutter stock requirement for blending this resid to fuel oil. Thus, the overall production of...

Singlestage Operation

Single Stage Once Through Hydrocracker

This operating mode has large effect on the product yield and quality. Single-stage operation produces about 0.3 bbl naphtha for every barrel of middle distillate. The single stage scheme is adapted for conversion of Figure 3-1. Hydrocracker operation, once-through and partial-recycle modes. Figure 3-1. Hydrocracker operation, once-through and partial-recycle modes. RECYCLE STREAM FRACTIONATOR BOTTOMS Figure 3-2. Two-stage hydrocracking process. vacuum gas oils into middle distillate and allows...

Dehydrogenation

The naphthenic hydrocarbons are dehydrogenated to form aromatics see Figure 4-1 . The reaction is extremely fast, and the yields obtained 1 Dehydrogenation of napthenes to aromatics with energy absorption II lt I 3H2 50 kCal mole 2 Isomerization of normal paraffins to isoparaffins C6H14 , CH3 CH CH2 CH2 CH3 2 kCal mole 3 Dehydrocyclization of paraffins C7H12 H2 OH- CHo CH3 CH CH2 CH3 CH3 CH CH3 -10 kCal mole 5 Secondary reactions Demethanation are almost those predicted by thermodynamics. Also,...

Hydrocracking Of Large Molecules

Hydrocracking of large hydrocarbon molecules into smaller molecules occurs in nearly all processes carried out in the presence of excess hydrogen. These reactions liberate about 50Btu scf of hydrogen consumed. The heat released from the hydrocracking reactions contributes appreciably to the total heat liberated in the reactor. Cracking reactions involving heavy molecules contribute to lowering the specific gravity and forming light products, such as gas and light naphtha, in the hydrocracker...

Heater Decoking

Decoking is done by first introducing 450 psig steam, shutting off the burners and charge pump, then allowing several minutes to elapse while the heater tubes are blown to the column. The 450 psig steam is shut off and the heater blocked with blinds. The decoking pipes are next connected to both the inlet and outlet of the heater and 150 psig steam is introduced at the inlet. One or more burners are lit in the preheat section to bring the steam temperature to 800 F. Water is introduced in the...

Notes

How to Predict Coke Yield. Hydrocarbon Processing September 1983 , p. 77. 2. R. Deblane and J. D. Elliot Delayed Coking Latest Trends. Hydrocarbon Processing May 1982 , p. 99. 3. H. R. Jansen. Conoco Coking Calcining Process. Kellogg Symposium on Heavy Oil Upgrading, Nice, France, September 1982. 4. A. Rhoe and C. DeBlignieres, Hydrocarbon Processing January 1979 H. Martin, Visbreaking, a Flexible Process, Oil and Gas Journal April 13, 1981 F. Stolfa, Hydrocarbon...

Solvent Deasphalting

Deasphalting

Historically, solvent deasphalting of vacuum residues has been used in the manufacture of lubricating oil to separate out the heavy fraction of crude oil beyond the range of economical commercial distillation, using propane as solvent. The feed to the deasphalting unit is usually a vacuum resid with a 950 F TBP cut point. Over time, this process has come to be used to prepare catalytic cracking feeds, hydrocracking feeds, hydro-desulfurizer feeds, and asphalts. Studies have shown that high...

Methanation

The absorber effluent is heated by heat exchange with the methanation reactor effluent and enters methanation reactor V-107, where the remaining small quantities of carbon oxides in the feed are converted to methane by passing through a methanation catalyst. Gas leaving the methanator is product hydrogen of 98 plus purity. The hydrogen purity depends on the oxygen purity, generator pressure, and conversion level in the shift reactors. The principle advantages of the partial oxidation process...

Permutation Cycle

The frequency of permutation is determined depending on the feed and unit design. If, for example, the overall run length of the ARDS unit is 64 weeks, the first permutation may be done after 20 weeks, when catalyst activity decrease or pressure drop increase in the lead reactor. For example, During weeks 1-20, both reactors 1A and IB , with reactor 1A in the lead position, are in operation. During weeks 21 and 22, 1A is under regeneration and only reactor IB is in operation. The feed rate may...

Mild Hydrocracking

Mild hydrocracking, as the name suggests, operates at much lower pressure and much milder other operating conditions than the normal hydrocracking process. The objective of the process is basically to desul-furize the VGO to make it suitable for FCCU feed. Other impurities, like nitrogen, are also removed and about 30 of the feed is converted into saleable diesel. Compared to normal hydrocracker units, mild hydrocrackers require much less initial investment. The operating conditions and yield...