If plug-flow is required, but the volume of the reactor is large, then plug-flow operation can be approached by using stirred tanks in series, since large volumes are often more economically arranged in stirred tanks than in tubular devices. This also can offer the advantage of better temperature control than the equivalent tubular reactor arrangement.  [c.54]

Figure 2.5 Heat transfer to and from stirred tanks. Figure 2.5 Heat transfer to and from stirred tanks.
The best way to avoid fugitive emissions is by using leak-tight equipment (e.g., changing from packing to mechanical seals or even using sealless pumps, etc.). If this is not possible, then regular maintenance checks can reduce fugitive emissions. If all else, fails, the equipment can be enclosed and ventilated. The air would then be treated before finally passing to the atmosphere. Storage tanks should be prevented from breathing to atmosphere. There are three broad methods which allow this to be achieved  [c.260]

Large quantities of toxic gases such as chlorine and ammonia and flammable gases such as propane and ethylene oxide can be stored either under pressure or at atmospheric pressure under refrigerated conditions. If there is a leak from atmospheric refrigerated storage, the quantity of hazardous material that is discharged will be less than that from a corresponding pressurized storage at atmospheric temperature. For large storage tanks, refrigeration is safer. However, this might not be the case with small-scale storage, since the refrigeration equipment provides sources for leaks. Thus, in small-scale storage, pressurization may be safer.  [c.265]

When process tanks, road tankers, or rail tank cars are filled, material in the vapor space is forced out of the tank and lost to atmosphere.  [c.289]

Install a waste-collection system for equipment cleaning and sampling waste that allows waste to be segregated and recycled where possible. This normally requires separate sewers for organic and aqueous waste, collecting to sump tanks, and recycle or separate and recycle if possible. If equipment is steamed out during the cleaning process, the plant should allow collection and condensation of the vapors and recycling of materials where possible.  [c.290]

By contrast, if the reactor is continuous well-mixed, then the reactor is isothermal. This behavior is typical of stirred tanks used for liquid-phase reactions or fluidized-bed reactors used for gas-phase reactions. The mixing causes the temperature in the reactor to be effectively uniform.  [c.327]

Fuel passing through certain hot zones of an aircraft can attain high temperatures moreover it is used to cool lubricants, hydraulic fluids, or air conditioning. It is therefore necessary to control the thermal stability of jet fuels, more particularly during supersonic flight where friction heat increases temperatures in the fuel tanks.  [c.229]

Hydrocarbon losses through evaporation are inevitable in spite of all the preventive steps that are or will be employed. Vapor recovery systems are obligatory in all fuel storage operations and service station systems ( Stage 1 ). These measures will soon extend to filling vehicle fuel tanks ( Stage 2"). Furthermore, new gasoline automobiles throughout Europe will be equipped with fuel tank vapor traps beginning the 1 January 1993. They are activated carbon canisters that trap and store the volatile hydrocarbons when the vehicle is stationary. When the vehicle is moving, the canisters are swept with air and the vapors are recovered as fuel. However this technique is not completely effective and needs to be complemented by very strict control of the fuel s vapor pressure a study conducted in the United States shows that for vehicles equipped with canisters, a reduction of 1 psi (69 mbar) in the vapor pressure causes a 46% reduction in evaporation for stationary cold vehicles and a 9% reduction for vehicles still stationary but after a period of warm operation.  [c.246]

During the course of operations such as filling and draining tanks and vessels, light hydrocarbons are lost. These losses are expressed as volume per cent of liquid. According to Nelson (1958), the losses can be evaluated by the equation (/ (/  [c.319]

To reduce these losses, the crude oils are stored in floating roof tanks.  [c.319]

In the 1950 s, crude oils were either corrosive (sour), or non-corrosive (sweet). Crudes containing more than 6 ppm of dissolved H2S were classed as sour because, beyond this limit, corrosion was observed on the walls of storage tanks by formation of scales of pyrophoric iron sulfides.  [c.322]

Solids materials that are insoluble in hydrocarbon or water can be entrained in the crude. These are called bottom sediments and comprise fine particles of sand, drilling mud, rock such as feldspar and gypsum, metals in the form of minerals or in their free state such as iron, copper, lead, nickel, and vanadium. The latter can come from pipeline erosion, storage tanks, valves and piping systems, etc. whatever comes in contact with the crude oil.  [c.327]

During storage, sediments decant with the water phase and deposit along with paraffins and asphalts in the bottoms of storage tanks as thick sludges or slurries (BS W). The interface between the water-sediment and the crude must be well monitored in order to avoid pumping the slurry into the refinery s operating units where it can cause serious upsets.  [c.327]

To lessen the risk of pumping sludges or slurries into a unit, the practice is to leave a safety margin of 50 cm (heel) below the outlet nozzle or install a strainer on the pump suction line. The deposits accumulate with time and the tanks are periodically emptied and cleaned.  [c.327]

Having been cleaned, the mud is transferred into mud tanks, large treatment and storage units. From there a powerful pump brings the mud up through a pipe stand pipe) and through a hose connected to the swivel (rotary hose) forcing it down the hole inside the drill string. Eventually the cleaned mud will exit again through the bit nozzles.  [c.39]

For dehydration of very high viscosity crudes, heaters can be used in combination with dehydration tanks. The temperature to which the crude is heated is a function of the viscosity required for effective separation.  [c.248]

Skimming tanks have already been described as the simplest form of de-oiling facility such tanks can reduce oil concentrations down to less than 200 ppm but are not suitable for offshore operations.  [c.248]

If several widely spaced fields are feeding a single gathering and treatment centre it is common to perform primary separation of gas and oil (and possibly water) in the field. A field station may include a simple slug catcher, temporary storage tanks and pumps for getting the separated fluids to the main gathering and treatment centre.  [c.261]

On a land site where space and weight are not normally constraints, advantage can be taken of tank type separation equipment such as wash tanks and settling tanks, and batch processing methods. Such equipment is generally cheaper to maintain than continuous throughput vessels, though a combination of both may be required.  [c.262]

Sales gas would be piped directly into the national gas distribution network (assuming one exists) and NGL products such as propane and butane can be stored locally in pressurised tanks. NGL products are often distributed by road or rail directly from the gathering station, although if ethane is recovered it is normally delivered by pipeline.  [c.263]

Two basic types of oil storage tank are in common use fixed roof tanks and floating roof tanks. Floating roof tanks are generally used when large diameters are required and there are no restrictions on vapour venting. Such tanks only operate at atmospheric pressures, and the roof floats up and down as the volume of crude increases or decreases respectively. There are a variety of fixed roof tanks for storing hydrocarbons at atmospheric pressure without vapour loss and for storage at elevated pressures.  [c.263]

Figure 10.29 Fixed roof and floating roof storage tanks Figure 10.29 Fixed roof and floating roof storage tanks
Storage tanks should always be closely surrounded by bund walls to contain crude in the event of a spillage incident, such as a ruptured pipe or tank, and to allow fire fighting personnel and equipment to be positioned reasonably close to the tanks by providing protected access.  [c.263]

The legs of the platform can be used as settling tanks or temporary storage facilities for crude oil where oil is exported via tankers, or to allow production to continue in the event of a pipeline shut down. The Brent D platform in the North Sea weighs more than 200,000 tonnes and can store over a million barrels of oil. Topside modules are either installed offshore by lift barges, or can be positioned before the platform is floated out.  [c.266]

The surface facilities used to perform these functions are discussed in Section 10.1, and are installed as a sequence or train of vessels, valves, pipes, tanks etc. This section  [c.340]

Acoustic Emission (AE) has been used as NDT method in a number of different applications covering a broad industrial range such as petrochemical industries, process monitoring, aerospace, welding, transformers and bearing testing " 1 Besides being a real time NDT method, the global nature of AE allows the inspection of large structures with a few sensors without scanning and without requiring access to the inside of the structure. The reduction of maintenance cost and the fact that AE succeeded in cases where other traditional NDT methods failed, made the AE widely accepted, specially in the petrochemical industries ". The application of AE succeeded in drastically decreasing the catastrophic failures of FRP pressure vessels and storage tanks and led major regulatory organisations to adopt AE in their codes and standards " . However most of the existing standards, adopt the philosophy of safe life design according to which the structure should not sustain any damage under normal operating conditions and the respective evaluation criteria give a pass/fail indication and not an assessment of structural integrity in terms of ranking defects criticality as required by the damage tolerance design philosophy .  [c.37]

Global intensity criteria have been developed and are used in industrial field testing application for the assessment of structural integrity of FRP tanks and pressure vessels l A step forward to increase the applicability of the technique is the complete source characterisation and the definition of evaluation/intensity criteria for each type of AE source. Source characterisation and signature recognition of AE signals, are difficult tasks and are not yet fully adopted by the field testing application experts, mainly due to luck of universal procedures and methodologies. Research in this direction focus on the application of artificial intelligence and more specific Pattern Recognition techniques which increases the possibilities for the identification of Signature of AE signals emitted from Composite Structures. An unsupervised pattern recognition technique was recently established consisting of procedures for descriptors selection, data clustering and techniques to validate the resulting partitions. Representative AE results from laboratory coupon testing and field testing of pressure vessel are presented, demonstrating the advantages of the proposed metliod as well as tlie limitations and the needs for further development.  [c.38]

Recommended Practice for Acoustic Emission Testing of Fiberglass Tanks/Vessels", 1987, THE SOCIETY OF THE PLASTICS INDUSTRY (SPI)  [c.44]

MP-suspension by automated ASTM-bulb Magnetization current by Hall-Sensor Magnetization time UV-Light intensity All Liquids (fluorescence, contamination) Process times and temperatures Function of spraying nozzles, Level of tanks Flow rates (e.g. washing, water recycling) UV-Light intensity  [c.629]

Examples will cover maintenance inspection such as corrosion detection in piping and tanks, but also routine weld inspection. The need for acceptance criteria for weld defects adapted for modern NDT techniques will be highlighted, because these form (in many cases) the key to benefit.  [c.945]

In order to control the tightness of welded joints on various products and structures, a range of units and complexes for control of pipes, pipelines, tanks, protective casings were developed, in particular, a set of put-on vacuum chambers for sheet structures.  [c.969]

Over the past years FORCE Institute has modified the P-scan system for several applications on a wide range of composite structures. By means of flexible scanner units combined with the P-scan processor, F ORCE Institute has achieved promising results with on-site automated ultrasonic inspection of fibre-reinforced polymers, such as aircraft structures, GFRP-pipes, vessels, tanks and ship structures. These results have initiated a close co-operation between FORCE Institute, RISO and two major producers of wind turbine rotor blades with the main goal to improve non-destructive inspection techniques for inspection of modern wind turbine rotor blades. Today modern rotor blades are mainly produced as a large GFRP-structure. As a consequence of application of larger and larger rotor blades, safety considerations mandate new requirements for inspection techniques that can be used to gain information of the quality of these blades.  [c.980]

Unprotected steel corrodes at a rate which is generally assumed to be 0.1 to 0.2mm per annum. Factors that influence the actual rate of corrosion include the maintenance program applied by the owner - particularly preservation of protective coatings, efficiency of cathodic protection systems in ballast tanks, corrosive properties of the cargo carried and environmental factors such as temperature and humidity. Under extreme conditions it has been known for the annual rate of corrosion on unprotected steel exposed on both surfaces to approach 1mm.  [c.1048]

TATTERSON Fluid Mixing and Gas Dispersion in Agitated Tanks TATTERSON Scale-up of Industrial Mixing Processes VVILLIG Environmental TQM  [c.462]

Tender Assisted Drilling. In some cases oil and gas fields are developed from a number of platforms. Some platforms will accommodate production and processing facilities as well as living quarters. Alternatively these functions may be performed on separate platforms, typically in shallow and calm water. On all offshore structures however, the installation of additional weight or spaoe is costly. Drilling is only carried out during short periods of time if eompared to the overall field life span and it is desirable to have a rig installed only when needed. This is the concept of tender assisted drilling operations. A derrick is assembled from a number of segments transported to the platform by a barge. All the supporting functions such as storage, mud tanks and living quarters are located on the tender, which is a specially built spacious barge anchored alongside. It is thus possible to service a whole field or even several fields using only one or two tender assisted derrick sets. In rough weather, barge type tenders quickly become inoperable  [c.34]

The simplest way to dehydrate or de-oil an oil water mixture is to use settlingor skimming tanks respectively. Over time the relative density differences will separate the two liquids. Unfortunately this process takes time and space, both of which are often a constraint in  [c.246]

Concrete or steel gravity based structures can be deployed in similar water depths to steel jacket platforms. Gravity based platforms rely on weight to secure them to the seabed, which eliminates the need for piling in hard seabeds. Concrete gravity based structures (which are by far the most common) are built with huge ballast tanks surrounding hollow concrete legs. They can be floated into position without a barge and are sunk once on site by flooding the ballast tanks. For example, the Mobil Hibernia Platform (offshore Canada) weighs around 450,000 tonnes and is designed and constructed to resist iceberg impact  [c.266]

A study is at present being carried out to check and validate the feasability of acoustic emission monitoring of the pneumatic testing of tanks. This study is being carried out in the context of the CIAPES program. This article gives only a brief summary of the results obtained on various materials, and different types of vessels, under different operating conditions.  [c.54]

The acoustic emission technique (AE) is a modem, dynamic developing method of non-destmctive testing, which is standard used in many technical branches, especially at pressure vessels, storage tanks and systems evaluation. Besides these yet classic branches are gradually developed number of another areas with promising utilisation of the acoustic emission virtues. Institute of Design of the Technical University in Bmo laboratories are predominantly aimed on material contact fetigue observation and on bearings deterioration. In the last years we focused on possibilities of the AET utilisation in this area. At resistance against the contact fatigue evaluation it is very important the most precise separation of the material surface damage individual stages. At present time we try to substitute the classic way of vibrations measurement by sensors through modem system of observation by acoustic emission technique, which provides considerably better information about events in loaded material.  [c.59]

Wlodarczyk S., Dybiec Cz., Wlodarczyk W, The application of eddy currents and other techniques for measuring corrosion of metal tanks during exploitation. Materials CCl National Conference about Science and practice in fighting against corrossion , Kule May 1994.  [c.388]

These Systems were built for Westinghouse Hanford Company (WHC) for use in high level waste tank sampling operations performed by the Tank Waste Remediation Systems (TWRS) Project. A total of four, highly specialized Systems, designated as XRI-001 through XRI-004 by WHC are referred to on-site as the x-ray hot-dog carts. The systems are used to remotely image the inner contents of specially designed, 26-inch length, one and one-half inch diameter, stainless steel core sample tubes and the high level radioactive waste contents following the remote sample segments removal from underground waste storage tanks. A real time radiographic view (x-ray) of the sampler and it s contents are displayed on live video monitors, is video taped, and selected freeze-frame image views can be immediately printed in the field. These images allow the field operations personnel to directly monitor sample recovery volume and the waste s physical characteristics, e g., sludge, solid or liquid. This data provides a technical basis which allows the engineers to adjust the drilling/sampling platform operating parameters to optimize sample recovery efforts. Electrical power for x-ray systems (and all the associated sampling equipment) is provided by separate, portable diesel generators.  [c.610]

Another technique to be mentioned here is Long Range Ultrasonics (RTD LORUS), which is capable of transmitting and receiving ultrasonic waves over an extended range, e.g. 1 metre. This method is used for corrosion detection in annular plates in storage tanks, see figure 3. since the annular plate is a critical component, and the tank does not need to be taken out of service for this inspection, the LORUS technique is a potential money saver. Similar techniques, for ranges up to 12 and more metres, are under development.  [c.949]

In addition to the examinations made for Classification purposes the shipbuilder may decide that additional checkpoints are to be taken for quality control purposes. The introduction of the faster and more convenient ultrasonic testing method has provided shipyards with the means to expand their quality control programmes beyond the minimum requirements of Classification. Where the quality programme dictates that cargo tanks must be absolutely secure the extent of welding tested in one ship will be measured in kilometres. In cases where shipbuilders are working to a quality assurance scheme the Surveyor s role will include a review of the Quality Control department to assess the competence of personnel, adequacy of procedures and the quality of reporting. Most importantly the Surveyor should be looking for an identified repair rate at which the Quality Control department will impose corrective action.  [c.1041]

Detection of fatigue cracks by visual inspection in salt water ballast tanks can be assisted by the colour contrast given by the protective coating - if still intact. Fatigue cracks are likely to be first observed as discolourations at breaks in the protective coating. In cargo tanks this visual aid may not be available to the Surveyor and other detection methods will be needed if inspections for incipient fatigue cracking are to be made.  [c.1047]

The NDE method used to monitor general corrosion is ultrasonic thickness measurement. Owing to the vast surface areas involved, for example, approximately 300,000 m in a large tanker or bulk carrier, the inspection effort will be focused on the items judged to be of greatest significance such as the cargo holds, double bottom and transverse bulkhead structure in bulk carriers, (Figure 1) or the deckhead,tank bottom and side shell structure in oil tankers and the salt water ballast tanks in all ship types.  [c.1048]

See pages that mention the term Tanks : [c.101]    [c.341]    [c.41]    [c.264]    [c.340]   
Gas turbine engineering handbook (2002) -- [ c.0 ]

Applied Process Design for Chemical and Petrochemical Plants, Volume 1 (1999) -- [ c.320 ]