Maleic anhydride processes

Air is compressed to modest pressures, typically 100 to 200 kPa ( 15-30 psig) with either a centrifugal or radial compressor, and mixed with superheated vaporized butane. Static mixers are normally employed to ensure good mixing. Butane concentrations are often limited to less than 1.7 mol 1 to stay below the lower flammable limit of butane (144). Operation of the reactor at butane concentrations below the flammable limit does not eliminate the requirement for combustion venting, and consequendy most processes use mpture disks on both the inlet and exit reactor heads. A dow diagram of the Huntsman fixed-bed maleic anhydride process is shown in Figure 1. 

Fig. 1. Schematic dow diagram of the Huntsman fixed-bed maleic anhydride process. MAN = maleic anhydride.

Like propane, n-hutane is mainly obtained from natural gas liquids. It is also a hy-product from different refinery operations. Currently, the major use of n-hutane is to control the vapor pressure of product gasoline. Due to new regulations restricting the vapor pressure of gasolines, this use is expected to he substantially reduced. Surplus n-butane could be isomerized to isobutane, which is currently in high demand for producing isobutene. Isobutene is a precursor for methyl and ethyl tertiary butyl ethers, which are important octane number boosters. Another alternative outlet for surplus n-butane is its oxidation to maleic anhydride. Almost all new maleic anhydride processes are based on butane oxidation. 

Figure 6-5. The DuPont butane to maleic anhydride process. ...

In industrial applications the achievement of higher activity and selectivity is of course desirable. However, beyond a certain point, they are not the driving forces for extensive research. For instance, current processes for epoxidation of ethylene to ethylene oxide on silver catalysts are so optimized that further increases in selectivity could upset the heat-balance of the process. Amoco s phthalic acid and maleic anhydride processes are similarly well energy-integrated (7). Rather than incremental improvements in performance, forces driving commercial research have been... 

Further examples of attempts to replace olefins by alkanes as a starting materials, as in the maleic anhydride process, are the development of processes for selective oxidation and ammoxidation. Examples are processes for acrolein, acrylic acid (Table 2, entry 19) and acrylonitrile (Table 2, entry 20) using propane as a feedstock... 

Fig. 6.16. Major emission sources from the maleic anhydride process.

Scientific Design Company, Inc. Fumaric acid Maleic acid License available in conjunction with maleic anhydride process 5 1986... 

Butane to Maleic Anhydride Process, Maleic anhydride is an unsaturated diacid that is used in the manufacture of several key products.The chemistry, applications, and process technology of MAN have been described in several comprehensive reviews. 

Merims, R, Clifton, P. V., Catalvst selectivity key to maleic anhydride process. Europ. Chem. /fare, Large Plant SuppL, 136-138 (27 ScpL 1968). 

EPA has recently found the maximum individual risks and total population risks from a number of radionuclide and benzene sources to be too low to be properly described as "significant". Specifically, benzene emissions from maleic anhydride process vents created maximum individual risks of 7.6 in 100,000 and an aggregrate yearly cancer incidence of twenty-nine thousandths of... 

Application INEOS is the recognized world leader in fluid-bed reactor technology for maleic anhydride production, which it licenses through INEOS Technologies. In addition to technology licensing, INEOS Technologies manufactures and markets the catalyst that is used in both the fixed-bed and fluid-bed reactor maleic anhydride processes. 

Figure 10 DuPont transport bed maleic anhydride process.

No process better illustrates the role of a catalyst in promoting selectivity than the Monsanto butane to maleic anhydride process. in 1966 the remarkable catalytic oxidation of... 

To exemplify the approach, the butane oxidation to maleic anhydride process is presented. The required information on hydrodynamics and mass transfer can be obtained from the equations given in Table 3. These equations have been verified for turbulent fluidized bed reactor applications of butane oxidation. Different correlations are required for other applications. 

The fluidized bed maleic anhydride process, however, has also several apparent disadvantages ... 

The success of the butane-based maleic anhydride process occurred at the cost of a dramatic drop of molar selectivity (at most 65-67% compared with 75-77% when starting from benzene) and a drop of productivity by nearly 20%. Compared with the benzene route, butane oxidation gives molar yields per pass at about 55% instead of 75% in the cyclic process [2]. 

Estimate the cost of operating labor (Cqi), the cost of utilities Cuj), and the cost of manufacturing (COM ) for the maleic anhydride process given in Project B.5 of Appendix B. You must do Problem... 

Consider the maleic anhydride process shown in Appendix B.5. Estimate the profit margin for this process using the costs of raw materials and products from Table 8.4. 

Clearly, from an analysis of the profit margin, further investigation of the maleic anhydride process is warranted. 

For the Maleic Anhydride flowsheet given in Appendix B, Figure B.5.1. list the minimum input information required to obtain mass and energy balances for this process. Using the process simulator available to you, simulate the Maleic Anhydride process and conpare your results to those given in... 

A process flow diagram for the reactor section of the maleic anhydride process is shown in Figure B.5.1. Benzene is vaporized in E-601, mixed with conpressed air, and then heated in a fired heater, H-601, prior to being sent to a packed-bed catalytic reactor, R-601, where the following reactions take place. 

Figure B.5.1 Unit 600 Maleic Anhydride Process Flow Diagram...

Titanium dioxide catalysts were first described in the 1940s and 1950s, when mixed oxide catalysts were being investigated and used in a number of oxidation reactions. Mixtures of vanadium pentoxide with titanium dioxide gave better operation and longer life as phthalic anhydride demand increased. An early catalyst that did not sinter and clearly increased the stability of vanadium pentoxide was described in a patent as Ti0(V03)2. At about the same time vanadium pentoxide/phosphorous pentoxide mixtures were also being developed for use in maleic anhydride processes. 

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