Alternative Control Techniques Document— Nitric And Adipic Acid

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Figure 3-6. Basic adipic acid manufacturing process. 18 3-18
. Ninety-eight percent of adipic acid produced in the United States is manufactured from cyclohexane in a continuous operation. Cyclohexane is air-oxidized, producing a cyclohexanol-cyclohexanone (ketone-alcohol, or KA) mixture. This mixture is then catalytically oxidized using 50 to 60 percent nitric acid, producing adipic acid. Phenol hydrogenation followed by nitric acid oxidation is the lesser-used method. 8,16 3.2.2.1 Oxidation of Cyclohexane. In commercial use, two approaches predominate the air oxidation of cyclohexane process: cobalt-catalyzed oxidation and borate-promoted oxidation. A third method, the high-peroxide process, has found limited commercial use. Cobalt-catalyzed air oxidation of cyclohexane is the most widely used method for producing adipic acid. Cyclohexane is oxidized with air at 150E to 160EC (302E to 320EF) and 810 to 1,013 kPa (about 8 to 10 atm) in the presence of the cobalt catalyst in a sparged reactor or multistaged column contactor. Several oxidation stages are usually necessary to avoid over- oxidizing the KA mixture. Oxidizer effluent is distilled to recover unconverted cyclohexane then recycled to the reactor feed. The resultant KA mixture may then be distilled for improved quality before being sent to the nitric acid oxidation stage. This process yields 75 to 80 mole percent KA, with a ketone to alcohol ratio of 1:2. 16 Borate-promoted oxidation demonstrates improved alcohol yields. Boric acid reacts with cyclohexanol to produce a borate that subsequently decomposes to a thermally stable borate ester, highly resistant to further oxidation or degradation. Another key feature of the borate-promoted oxidation system is the removal of byproduct water from the reactors using inert gas and hot cyclohexane vapor. Reaction yields of 87 percent and a K:A ratio of 1:10 have been achieved. 16 The high-peroxide process is an alternative to maximizing selectivity. Noncatalytic oxidation in a passivated reactor results in maximum production of cyclohexylhydroperoxide. This 3-19
Page 1 and 2: Alternative Control Techniques Docu
Page 3 and 4: ALTERNATIVE CONTROL TECHNIQUES DOCU
Page 5 and 6: TABLE OF CONTENTS iii Page 5.0 CONT
Page 7 and 8: LIST OF TABLES v Page TABLE 2-1. NO
Page 9 and 10: LIST OF FIGURES vii Page Figure 3-1
Page 11 and 12: discussion of NO emission levels is
Page 13 and 14: TABLE 2-1. NO EMISSIONS AND COST CO
Page 15 and 16: 2-4
Page 17 and 18: Four plants in the United States pr
Page 19 and 20: 3.0 DESCRIPTION OF NITRIC/ADIPIC AC
Page 21 and 22: Figure 3-1. Basic nitric acid produ
Page 23 and 24: plants operating at 0.8 megaPascals
Page 25 and 26: 3.1.3 Plant Design Corrosive effect
Page 27 and 28: . 3.1.3.2 Dual-Pressure Process. Th
Page 29 and 30: . In the dual-pressure process, amm
Page 31 and 32: Figure 3-4. Nitric acid concentrati
Page 33 and 34: Figure 3-5. Nitric acid concentrati
Page 35: Two methods of producing adipic aci
Page 39 and 40: and transported to the adipic acid
Page 41 and 42: 4.0 CHARACTERIZATION OF NO EMIS x 4
Page 43 and 44: 3 expensive to control. The difficu
Page 45 and 46: typical for steady-state, continuou
Page 47 and 48: factor represents NO in the form of
Page 49 and 50: 5.0 CONTROL TECHNIQUES FOR NITROGEN
Page 51 and 52: Figure 5-1. Extended absorption sys
Page 53 and 54: Figure 5-2. Extended absorption sys
Page 55 and 56: 5.1.1.3 Performance of Extended Abs
Page 57 and 58: illustrates the levels to which ext
Page 59 and 60: Figure 5-3. Nonselective catalytic
Page 61 and 62: than 140 percent of stoichiometry).
Page 63 and 64: Poor control of the fuel/oxygen rat
Page 65 and 66: illustrates the level of control th
Page 67 and 68: 5.1.3.1 Description of SCR Systems.
Page 69 and 70: is a flow diagram for a typical nit
Page 71 and 72: Figure 5-5. SCR catalyst performing
Page 73 and 74: Figure 5-6. SCR catalyst performanc
Page 75 and 76: TABLE 5-3. NITROGEN OXIDES EMISSION
Page 77 and 78: European plants using SCR. The data
Page 79 and 80: TABLE 5-5. SUMMARY OF NO CONTROL TE
Page 81 and 82: Figure 5-7. Process flow diagram fo
Page 83 and 84: 6.8 to 13.0 kPa (1-2 psi), which al
Page 85 and 86: . The process control device consis
Page 87 and 88:
Figure 5-9. Schematic diagram of th
Page 89 and 90:
Figure 5-10. Molecular sieve system
Page 91 and 92:
level of achievable NO control. Sec
Page 93 and 94:
is a flow diagram for the nitric ac
Page 95 and 96:
0.41 to 1.23 kg per metric ton (0.8
Page 97 and 98:
is a simplified flow diagram of an
Page 99 and 100:
TABLE 5-6. NITROGEN OXIDES EMISSION
Page 101 and 102:
Instead, the major sources of NO em
Page 103 and 104:
5.3 REFERENCES 1. Review of New Sou
Page 105 and 106:
30. Screening Study to Determine Ne
Page 107 and 108:
maintenance materials, replacement
Page 109 and 110:
TABLE 6-1. CAPITAL COST SUMMARY FOR
Page 111 and 112:
TABLE 6-2. ANNUAL COST SUMMARY FOR
Page 113 and 114:
than the direct and indirect operat
Page 115 and 116:
Chapter 5. For costing purposes, it
Page 117 and 118:
TABLE 6-4. ANNUAL COST SUMMARY FOR
Page 119 and 120:
Estimates of indirect operating cos
Page 121 and 122:
TABLE 6-6. CAPITAL COST SUMMARY FOR
Page 123 and 124:
for blowers can be eliminated if pr
Page 125 and 126:
shows the annual costs for an SCR s
Page 127 and 128:
TABLE 6-8. COST EFFECTIVENESS FOR N
Page 129 and 130:
system is described in detail in Ch
Page 131 and 132:
presents the estimated annual costs
Page 133 and 134:
6.2.2.2 Annual Costs. Table 6-10 6-
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shows the annual costs for a therma
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shows the cost presents the cost ef
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7.0 ENVIRONMENTAL AND ENERGY IMPACT
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. For each of the three model plant
Page 143 and 144:
TABLE 7-2. ANNUAL ELECTRICITY REQUI
Page 145 and 146:
TABLE 7-3. NO EMISSIONS FROM ADIPIC
Page 147:
a significant amount of heat, which
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Alternative Control Techniques Document— Nitric And Adipic Acid

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