Increasing Unit Throughput

We note that yield of light products (dry gas and LPG) does not increase. This indicates that high temperature thermal or catalytic cracking is not taking place. 

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Modem coking units operate at 10% or less combined feed ratio (CFR) (as low as 3%) to increase unit throughput. Recycle ratio is used to control the endpoint of the coker gas oil. An increase in the recycle ratio causes... 

A better solution for preparative columns is the development of separation media with substantially increased selectivities. This approach allows the use of shorter columns with smaller number of theoretical plates. Ultimately, it may even lead to a batch process in which one enantiomer is adsorbed selectively by the sorbent while the other remains in the solution and can be removed by filtration (single plate separation). Higher selectivities also allow overloading of the column. Therefore, much larger quantities of racemic mixtures can be separated in a single run, thus increasing the throughput of the separation unit. Operation under these overload conditions would not be possible on low selectivity columns without total loss of resolution. 

The Production of a surfactant is to be increased from 15,000,000 to 20,000,000 lb / yr. With many new processes and some older ones, the operators and engineers find they can increase the throughput in certain units but are prevented from increasing production because other steps are running at the highest possible rates. The latter steps are called the bottlenecks. The process engineer must determine how to remove the bottlenecks from the process. 

For each unit that cannot produce at 20,000,000 lb / yr it must be decided whether the unit should be replaced with a larger one, whether a parallel unit should be installed, or whether to change operating conditions (which may require other modifications) and not make any changes in the equipment. An example of the latter would be to decrease the time each batch spends in the reactor. This would decrease the yield but increase the throughput. 

Increasing the throughput of the unit may involve recycling of the unconverted bottoms, its analysis has shown accumulation of complex polynuclear aromatics, such as coronene (seven-rings PAH). However, they could have been produced on reaction or were originally present and could not be converted under reaction conditions. 

Flow injection analysis is based on the injection of a liquid sample into a continuously flowing liquid carrier stream, where it is usually made to react to give reaction products that may be detected. FIA offers the possibility in an on-line manifold of sample handling including separation, preconcentration, masking and color reaction, and even microwave dissolution, all of which can be readily automated. The most common advantages of FIA include reduced manpower cost of laboratory operations, increased sample throughput, improved precision of results, reduced sample volumes, and the elimination of many interferences. Fully automated flow injection analysers are based on spectrophotometric detection but are readily adapted as sample preparation units for atomic spectrometric techniques. Flow injection as a sample introduction technique has been discussed previously, whereas here its full potential is briefly surveyed. In addition to a few books on FIA [168,169], several critical reviews of FIA methods for FAAS, GF AAS, and ICP-AES methods have been published [170,171]. 

Another significant challenge remains in further increasing the efficiency with which sample species are utilized through increased ion throughput and duty factor. Currently many of the ions generated by continuous ionization sources are lost because of the pulsed nature of the instrument. Realization of higher duty factor and the unit transmission efficiency of which TOF-MS is capable could propel the TOF-MS into a sensitivity realm well beyond that of current mass analyzers. 

The addition of a MaxEne process to the flow scheme provides several benefits, beginning with an increase in throughput of 18%. With this higher feed rate, the MaxEne extract stream matches the capacity of the cracker, 34.1 weight units. However, the MaxEne extract is a preferable feed for the cracker because of its high normal paraffin content. Consequently, the yield pattern from the cracker, in Table 4.12, is improved. Olefins increase by 15%, with ethylene increasing by almost 50%. In addition, LPG increases by 32%. 

Nowadays, building new refinery units is very costly. Therefore, many retrofit projects to the existing crude oil distillation system are considered to increase the production capacity of the refinery by increasing the throughput. 

The control system is automatic, with little operator attention required. There are three variables that affect operation. They are throughput rate, chlorine feed rate, and system pressure. The throughput rate has been designed for an expected solids concentration. The process chlorine feed is set based on the expected rate of solids fed to the oxidation unit. If the actual solids concentration increases, the throughput rate should be lowered. 

As the perceived market value of organic residues increases, changes will be made to the basic system to increase efficiency. Further developments are also planned to improve the overall economics of the system. If operated in a starved-air mode with a fire box downstream from the combustion cell, capital costs for the burner and boiler per unit throughput can be decreased, and more advantage can be taken of the radiant effects on heat transfer. As the costs of energy continue to increase relative to the basic price indices, the economics of fluidized-bed combustion of biomass to recover energy will continue to improve. 

Effect of feed bond width. An increase in the width of the feed band will increase the product throughput in the unit in proportion to the increase in 0f (for constant Cf). The payoff for this increased throughput comes in a resulting decrease in resolution. The decrease in resolution arises predominantly because of an increase in the width of the solute band in the column. For the conditions of this simulation, the payoff for a factor of 4 increase in throughput is a decrease in peak resolution by a factor of only about 0.7. 

The process utilizes the eoncept of short residence time of the feed coal thereby increasing the throughput of coal per unit of cross-sectional area with the subsequent higher production of liquid products. 

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