Intermediate product stream

The significance of industrial acrolein production may be clearer if one considers the two major uses of acrolein—direct oxidation to acryUc acid and reaction to produce methionine via 3-methyhnercaptopropionaldehyde. In acryUc acid production, acrolein is not isolated from the intermediate production stream. The 1990 acryUc acid production demand in the United States alone accounted for more than 450,000 t/yr (28), with worldwide capacity approaching 1,470,000 t/yr (29). Approximately 0.75 kg of acrolein is required to produce one kilogram of acryUc acid. The methionine production process involves the reaction of acrolein with methyl mercaptan. Worldwide methionine production was estimated at about 170,000 t/yr in 1990 (30). (See Acrylic ACID AND DERIVATIVES AmINO ACIDS, SURVEY.)... 

Next to the ubiquitous CSTR, the distillation column is probably the most popular and important process studied in the chemical engineering literature. Distillation is used in many chemical processes for separating feed streams and for purification of final ami intermediate product streams. 

Kriging metamodels xB = Molar fraction of Benzene in distillate xT = Molar fraction of Toluene in intermediate product stream xX = Molar fraction of Xylene in Bottoms stream Q = Heat flow in the reboiler (kW)... 

Stabilized as extractable compounds (VO -oxidation during the first cycle coextraction) the actinides will follow the heavy metal and can be separated from the intermediate product stream of the first cycle. This stream has a low fission product concentration, and the THOREX-process is discontinued anyhow at that step, but, of course, the insertion of a new component amidst an established process will cause unfavourable consequences. 

One difficulty with the cascade shown in Figure 3-1 is that the intermediate product streams, L, L2, V4, and V5, are of intermediate concentration and need further separation. Of course, each of these streams could be fed to another flash cascade, but then the intermediate products from those cascades would have to be sent to additional cascades, and so forth. A much cleverer solution is to use the intermediate product streams as additional feeds within the same cascade. 

Plasma fractionation is unusual in pharmaceutical manufacturing because it involves the processing of proteins and the preparation of multiple products from a single feedstock. A wide range of unit operations are utilized to accompHsh these tasks. They are Hsted in Table 3 some are common to a number of products and all must be closely integrated. The overall manufacturing operation can be represented as a set of individual product streams, each based on the processing of an intermediate product derived from a mainstream fractionation process (Fig. 1). 

Flow-sheet models are used at all stages in the life cycle of a process plant during process development, for process design and retrofits, and for plant operations. Input to the model consists of information normally contained in the process flow sheet. Output from the model is a complete representation of the performance of the plant, including the composition, flow, and properties of all intermediate and product streams and the performance of the process units. 

The delayed coking feed stream of residual oils from various upstream processes is first introduced to a fractionating tower where residual lighter materials are drawn off and the heavy ends are condensed. The heavy ends are removed and heated in a furnace to about 900 to 1,000 F and then fed to an insulated vessel called a coke drum where the coke is formed. When the coke drum is filled with product, the feed is switched to an empty parallel drum. Hot vapors from the coke drums, containing cracked lighter hydrocarbon products, hydrogen sulfide, and ammonia, are fed back to the fractionator where they can be treated in the sour gas treatment system or drawn off as intermediate products. 

Safety valve releases are routed to blowdown drums when the presence of liquid, toxic properties or other factors would make discharge to the atmosphere hazardous. Product and intermediate process streams may need to be diverted to alternative disposal if they are off-specification (e.g., during startup) or in the event of emergency shutdown of downstream equipment. 

The selection of continuous over-batch processing is driven by two factors economics and control [1]. Hitherto, this discussion had largely focused on the former. Continuous processes inherently require a greater degree of measurement and control (Section 14.4), a reflection of the shorter timescales over which process or product manipulation must be made in order to assure that intermediate and product streams remain to specification. 

Steam reforming of glycerol for hydrogen production involves complex reactions. As a result, several intermediate by-products are formed and end up in the product stream, affecting the final purity of the hydrogen produced. Furthermore, the yield of hydrogen depends on several process variables, such as the system pressure, temperature and water-to-glycerol feed ratio. 

The material streams, states, and their balances are divided into four categories namely raw materials, intermediates, products, and fuel system. All material balances are carried out on a mass basis. However, volumetric flow rates are used in the case where quality attributes of some streams only blend by volume. 

Constraint (3.9) sets an upper bound on intermediate streams flow rates between the different refineries. The integer variable y pipeR fi represents the decision of exchanging intermediate products between the refineries and takes on the value of one if the commodity is transferred from plant i I to plant i C I or zero otherwise,... 

Constraints (5.13) and (5.14) represent the material balance that governs the operation of the petrochemical system. The variable x 1 represents the annual level of production of process m Mpa where ttcpm is the input-output coefficient matrix of material cp in process m Mpel. The petrochemical network receives its feed from potentially three main sources. These are, (i) refinery intermediate streams of an intermediate product cir RPI, (ii) refinery final products Ff ri of a final product cfr RPF, and (iii) non-refinery streams Fn px of a chemical cp NRF. For a given subset of chemicals cp CP, the proposed model selects the feed types, quantity and network configuration based on the final chemical and petrochemical lower and upper product demand Dpet and DPet for each cp CFP, respectively. In constraint (5.15), defining a binary variable yproc et for each process m Mpet is required for the process selection requirement as yproc et will equal 1 only if process m is selected or zero otherwise. Furthermore, if only process m is selected, its production level must be at least equal to the process minimum economic capacity B m for each m Mpet, where Ku is a valid upper... 

The model was then solved for the total refinery network and the PVC petrochemical complex. As shown in Table 5.4, the proposed model redesigned the refinery network and operating policies and also devised the optimal production plan for the PVC complex from all available process technologies. The model selected gas oil, an intermediate refinery stream, as the refinery feedstock to the petrochemical complex as opposed to the normally used light naphtha feedstock in industrial practice. In fact, this selection provided the optimal strategy as the light naphtha stream was used instead in the gasoline... 

It is undesirable in the North Sea to have more than two product streams—crude oil, and gas--leaving the production platform. All of the components contained in the producing well stream must leave the platform, or be consumed as fuel. Depending on the well stream composition, it is possible a combination of low crude oil vapor pressure and gas hydrocarbon dewpoint specifications, with limitations in separation selectivity, may result In a third product stream of intermediate (NGL) compo-nents which cannot be put into either the oil or gas streams. As previously discussed, a separate NGL pipeline system or offshore storage and loading of NGL will be uneconomic in the North Sea, and this factor will tend to encourage development of North Sea oil pipeline systems on a high vapor pressure crude basis. 

If produced gas is to be injected back into the producing formation or seme other formation, rather than delivered to a gas pipeline, it may be possible to inject the third product stream into the injection gas stream, or to inject it separately into the reservoir. However, this may be only a temporary solution to the problem, since the intermediate components could be reproduced again, and may be in higher concentrations than they were the first time. If injected gas is ultimately delivered to a gas pipeline, and if intermediate components have been injected also, the gas conditioning problem to meet dewpoint requirements will be more difficult at a later date. 

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