Feedstock tanks

The batch scale rotative reactor was developed and used as a tool to validate the new heat transfer model [4, 6]. The batch reactor consists of a well insulated tank which contains molten salt and is equipped with heating elements in order to be able to heat the salt to the set point temperature. A second well insulated tank can be placed in the salt bath. The feedstock enters the reactor through the feedpipe. The same agitation blades as those found in the industrial reactor are used. The stirring mechanism transports and agitates the feedstock in a circular manner. The center of the reservoir is kept free of feedstock by a scraping mechanism. The diameter of the feedstock tank is 107 cm and the effective heat transfer area is 0.82 m [6]. 

The discharge of vents and pressure relief pipes should be to areas safe from both the fire and toxic hazards. It should not be within a building. Since the vent of the feedstock storage tank must discharge a similar vapour in a safe place, the feedstock tank is often a suitable catchpot for the disengagement of any liquid droplets that may be carried by vent discharges, provided that sufficient ullage in the tank is maintained at aU times. 

While normal vents from a distillation unit may be routed via the feedstock tank, a dedicated dump tank should be provided if there is a serious risk of an exotherm being discharged through the safety valve. 

All feedstock tanks should have means of dipping (either by tape or dipstick) both to gauge their contents and to detect water layers lying either above or below the solvent layer. A drain valve to remove bottom water layer should be fitted and, because it is vulnerable to water freezing in it, this valve should be cast steel, not cast iron. 

Figure 6.24. A laboratory-scale MSMPR crystallizer. A, thermos tat ted feedstock tank B, constant-head tank C, MSMPR crystallizer D, water inlet to jacket E, baffle F, thermometer G, level detector H, solenoid-operated discharge valve /, magma outlet /, control unit...

Large quantities of butane are shipped under contract standards rather than under national or worldwide specifications. Most of the petrochemical feedstock materials are sold at purity specifications of 95—99.5 mol %. Butane and butane—petroleum mixtures intended for fuel use are sold worldwide under specifications defined by the Gas Processors Association, and the specifications and test methods have been pubHshed (28). Butanes may be readily detected by gas chromatography. Butanes commonly are stored in caverns (29) or refrigerated tanks. 

In the Sulser-MWB process the naphthalene fractions produced by the crystallisation process are stored in tanks and fed alternately into the crystalliser. The crystalliser contains around 1100 cooling tubes of 25-mm diameter, through which the naphthalene fraction passes downward in turbulent flow and pardy crystallises out on the tube walls. The residual melt is recycled and pumped into a storage tank at the end of the crystallisation process. The crystals that have been deposited on the tube walls are then pardy melted for further purification. Following the removal of the drained Hquid, the purified naphthalene is melted. Four to six crystallisation stages are required to obtain refined naphthalene with a crystallisation point of 80°C, depending on the quaHty of the feedstock. The yield is typically between 88 and 94%, depending on the concentration of the feedstock fraction. 

Feedstocks. Feedstocks are viscous aromatic hydrocarbons consisting of branched polynuclear aromatics with smaller quantities of paraffins and unsaturates. Preferred feedstocks are high in aromaticity, free of coke and other gritty materials, and contain low concentrations of asphaltenes, sulfur, and alkah metals. Other limitations are the quantities available on a long-term basis, uniformity, ease of transportation, and cost. The abiUty to handle such oils in tanks, pumps, transfer lines, and spray nozzles are also primary requirements. 

Unexpected component generated in storage tank during shutdown. Poor separation. Brought in fresh feedstock and tower worked. Operational problem. 

Like LNG, the natural gas-to-methanol fuel market relies on stranded gas as feedstock. The advantages of conversion to methanol is that it requires far less specialized infrastructure than LNG since the final product is a 110-octane liquid that ships in regular tanks, and does not need regasification. And because of a plentiful natural gas supply in the... 

Recycling of partially reacted feed streams is usually carried out after the product is separated and recovered. Unreacted feedstock can be separated and recycled to (ultimate) extinction. Figure 4.2 shows a different situation. It is a loop reactor where some of the reaction mass is returned to the inlet without separation. Internal recycle exists in every stirred tank reactor. An external recycle loop as shown in Figure 4.2 is less common, but is used, particularly in large plants where a conventional stirred tank would have heat transfer limitations. The net throughput for the system is Q = but an amount q is recycled back to the reactor inlet so that the flow through the reactor is Qin + q- Performance of this loop reactor system depends on the recycle ratio qlQin and on the type of reactor that is in the loop. Fast external recycle has... 

A plant is being designed that will require 20,000 lb of feedstock per day. A supplier has said he could guarantee that any order would be filled within 15 days of its receipt. It will be shipped by rail in 36,000-gallon jumbo tank cars. The time en route could be anywhere between 2 and 5 days. The specific gravity of fee feedstock is 0.85. 

If the supplier shipped the feedstock immediately, it could arrive in 2 days. He also could delay loading the tank car for 15 days, and the rail shipment could take 5 days. If the order were placed on the Saturday preceding a major holiday, there might be a 3-day delay before the supplier receives it. The maximum time between... 

A typical configuration for a methanol carbonylation plant is shown in Fig. 1. The feedstocks (MeOH and CO) are fed to the reactor vessel on a continuous basis. In the initial product separation step, the reaction mixture is passed from the reactor into a flash-tank where the pressure is reduced to induce vapourisation of most of the volatiles. The catalyst remains dissolved in the liquid phase and is recycled back to the reactor vessel. The vapour from the flash-tank is directed into a distillation train which removes methyl iodide, water and heavier by-products (e.g. propionic acid) from the acetic acid product. 

Crude oil, intermediate, and finished products are stored in tanks of varying size to provide adequate supplies of crude oils for primary fractionation mns of economical duration to equalize process flows and provide feedstocks for intermediate processing units and to store final products prior to shipment in adjustment to market demands. Generally, operating schedules permit sufficient detention time for settling of water and suspended materials. 

Salt caverns are developed by solution mining, a process (leaching) in which water is injected to dissolve the salt. Approximately 7 to 10 units of fresh water are required to leach 1 unit of cavern volume. Figure 10-190 illustrates the leaching process for two caverns. Modern salt dome caverns are shaped as relatively tall, slender cylinders. The leaching process produces nearly saturated brine from the cavern. Brine may be disposed into nearby disposal wells or offshore disposal fields, or it may be supplied to nearby plants as a feedstock for manufacturing of caustic (NaOH) and chlorine (CI2). The final portion of the produced brine is retained and stored in artificial surface ponds or tanks to be used to displace the stored liquid from the cavern. 

Biocatalyst slurry and high-sulfur petroleum feedstock are mixed with oxygen in a continuous stirred-tank reactor. 

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