Methanol plant

The cmde product from the gasifier contains CO2 and H2S, which must be removed before the gas can be used to produce chemicals. The Rectisol process is used to remove these contaminants from the gas. This is accompHshed by scmbbing the product with cold methanol which dissolves the CO2 and H2S and lets the H2 and CO pass through the scmbber. The H2S is sent to a Claus sulfur plant where over 99.7% of the sulfur in the coal feed is recovered in the form of elemental sulfur. A portion of the clean H2 and CO are separated in a cryogenic distillation process. The main product from the cryogenic distillation is a purified CO stream for use in the acetic anhydride process. The remaining CO and hydrogen are used in the methanol plant. 

The chemical complex includes the methanol plant, methyl acetate plant, and acetic anhydride plant. The methanol plant uses the Lurgi process for hydrogenation of CO over a copper-based catalyst. The plant is capable of producing 165,000 t/yr of methanol. The methyl acetate plant converts this methanol, purchased methanol, and recovered acetic acid from other Eastman processes into approximately 440,000 t/yr of methyl acetate. 

There has been an increasing interest in utilising off-gas technology to produce ammonia. A number of ammonia plants have been built that use methanol plant purge gas, which consists typically of 80% hydrogen. A 1250 t/d methanol plant can supply a sufficient amount of purge gas to produce 544 t/d of ammonia. The purge gas is first subjected to a number of purification steps prior to the ammonia synthesis. 

High temperature steam reforming of natural gas accounts for 97% of the hydrogen used for ammonia synthesis in the United States. Hydrogen requirement for ammonia synthesis is about 336 m /t of ammonia produced for a typical 1000 t/d ammonia plant. The near-term demand for ammonia remains stagnant. Methanol production requires 560 m of hydrogen for each ton produced, based on a 2500-t/d methanol plant. Methanol demand is expected to increase in response to an increased use of the fuel—oxygenate methyl /-butyl ether (MTBE). 

The high cost of coal handling and preparation and treatment of effluents, compounded by continuing low prices for cmde oil and natural gas, has precluded significant exploitation of coal as a feedstock for methanol. A small amount of methanol is made from coal in South Africa for local strategic reasons. Tennessee Eastman operates a 195,000-t/yr methanol plant in Tennessee based on the Texaco coal gasification process to make the methyl acetate intermediate for acetic anhydride production (15). 

Retrofitting features of the more efficient reactor types have been the principal thmst of older methanol plant modernization (17). Conversion of quench converters to radial flow improves mixing and distribution, while reducing pressure drop. Installing an additional converter on the synthesis loop purge or before the final stage of the synthesis gas compressor has been proposed as a debotdenecking measure. 

The nameplate capacity of worldwide methanol plants is given by country in Table 2 (27). A significant portion of this capacity is based on natural gas feedstock. Percent utilization is expected to remain in the low 90s through the mid-1990s. A principal portion of this added capacity is expected to continue to come from offshore sources where natural gas, often associated with cmde oil production, is valued inexpensively. This has resulted in the emergence of a substantial international trade in methanol. In these cases, the cost of transportation is a relatively larger portion of the total cost of production than it is for domestic plants. 

I. Rees, "BHP Petioleum s LCM Based Methanol Plant," 1993 World Methanol Conference Adanta, Ga. 

Y. Kobayashi and H. Nakamura, "MRF Reactor, Commercially Proven Performance and Enhancement for Large Scale Methanol Plant," HIChE... 

Based on these developments, the foreseeable future sources of ammonia synthesis gas are expected to be mainly from steam reforming of natural gas, supplemented by associated gas from oil production, and hydrogen rich off-gases (especially from methanol plants). 

Eastman Chemical Company has operated a coal-to-methanol plant in Kingsport, Tennessee, since 1983. Two Texaco gasifiers (one is a backup) process 34 Mg/h (37 US ton/h) of coal to synthesis gas. The synthesis gas is converted to methanol by use of ICl methanol technology. Methanol is an intermediate for producing methyl acetate and acetic acid. The plant produces about 225 Gg/a (250,000 US ton/a) of acetic anhydride. As part of the DOE Clean Coal Technology Program, Air Products and Cnemicals, Inc., and Eastman Chemic Company are constructing a 9.8-Mg/h (260-US ton/d) slurry-phase reactor for the conversion of synthesis gas to methanol and dimethyl... 

Figure 6-13 shows plots of equilibrium eonversion versus temperature. The plots indieate the eonversion is low at operating temperature T = 473 K (200°C), but ensures rapid reaetion. The eonversion per pass is low, therefore, it is important to maintain a high pressure to aehieve a high eonversion. Modern methanol plants operate at about 250°C and 30-100 atm and give nearly equilibrium eon versions using Cu/ZnO eatalysts. The unreaeted CO and Hj are reeyeled baek into the reaetor. 

Catalyst improvements allow methanol plants and plants using the Oxo process for aldehyde production to operate at lower pressures. The process also has a higher yield and produces a better quality product (Dale, 1987). 

SAQ 4.15 Use the data in the Resource Material to answer the following question. It is 1977. The bacterial SCP from methanol plant referred to in Table 4.9 does not produce protein at a price that competes with soya protein. By how much would the cost of methanol have to fall in order that the protein from such a plant can be produced competitively with soya protein You can assume i) that the SCP processes referred to in Tables 4.7 and 4.9 to 4.15 are of 2 x 10s tons annual capacity, ii) that yield on methanol is 0.5kg biomass per kg methanol, iii) bacterial SCP contains 60% protein. 

Extract of Case History Concerning the Reported Failure of Boiler Tubes in a Chilean Methanol Plant, 1,500 psig Waste Heat Boiler... 

Small but environrrientallyjnendly. The Chemical Engineer, March 1993 Huge increases in technology in the past distributed manufacturing in small-scale plants miniaturization of processes domestic methanol plant point-of-sale chlorine simpler and cheaper plants economy of plant manufacture process control and automation start-up and shut-down sensor demand [145],... 

This was "as far as the eye could see." The eye could not see beyond the construction site. He did not go to any of the camps. Though he remembered that Camp IV, built within a hundred yards of the methanol plant, was called "Monowitz," he understood it to be an ordinary work camp. 

The CFD calculations of the present work used conditions and compositions from a Johnson Matthey detailed reformer model of a methanol plant steam reformer with upwards flow, at typical operating conditions. Conditions were chosen corresponding to three different axial positions along the tube, to reflect reaction rates typical of those close to the inlet, midway down the tube and close... 

Methanol oxidation, 12 214 Methanol plant reformers, 16 303 Methanol processes. See also Methanol-to-entries... 

Table 7.13. Input and output data for a methanol plant with gasification and methanol synthesis ...

Methanol is produced from natural gas via combined reforming and downstream methanol synthesis. The technical data for the methanol plant have been derived from a methanol plant located in Tjeldbergodden in Norway (Larsen, 1998) (see Table 7.14). 

Larsen, H.H. (1998). The 2400 MTPD Methanol Plant at Tjeldbergodden. Haldor Topsoe A/S. 1998 World Methanol Conference. Frankfurt, Germany. 

Since 1923, methanol has been made commercially from synthesis gas, the route that provides most of the methanol today. The plants are oEten found adjacent to or integrated with ammonia plants for several reasons. The technologies and hardware are similar, and the methanol plant can use the CO2 made in the Haber ammonia process. In this case, the route to methanol is to react the CO2 with methane and steam over a nickel catalyst to give additional CO and H2 and then proceed to combine these to make methanol ... 

What s the synergy or affinity of ammonia and methanol plants ... 

In Canada, InterGroup Consulting Economists (O estimated wood procurement costs in 62 forest zones across the country and generated cost data for the 20 zones having sufficient surplus roundwood to sustain a minimum 18,000 tonne per year methanol plant operation, based on a biomass recovery of 30%. The procurement costs shown in Table II represent the delivered chip cost, as in the Battelle study, but include capital and operating costs on an undiscounted cost basis. Unlike the Battelle study, the estimate is based on oven dry wood. The final results are very similar. 

ATR is a stand-alone process which combines POX and SR in a single reactor. The ATR process was first developed in the late 1950s by Topsoe, mainly for industrial synthesis gas production in ammonia and methanol plants [27]. 

Fig. 10 Analysis of methanolic plant extract using MEEKC, SDS-octanol-butane-l-ol microemulsion, detection at 200 nm. (From Ref. 6.)...

This process has many similarities to NH3 synthesis. The pressure is not as high for acceptable conversions, and modem methanol plants operate at -250°C at 30-100 atm and produce nearly equilibrium conversions using Cu/ZnO catalysts with unreacted CO and H2 recycled back into the reactor. 

Methanol was first produced commercially in 1830 by the pyrolysis of wood to produce wood alcohol. Almost a century later, a process was developed in Germany by BASF to produce synthetic methanol from coal synthesis gas. The first synthetic methanol plant was introduced by BASF in 1923 and in the United States by DuPont in 1927. In the late 1940s, natural gas replaced coal synthesis gas as the primary feedstock for methanol production. In 1966, ICI announced the development of a copper-based catalyst for use in the low-pressure synthesis of methanol. 

Due to the greater number of moles of product produced, versus moles of reactants consumed i.e., 65 vs. 33 as in SR of n-Cig), the SR reaction is favored at low pressures, as shown in Figure 20. However, industrial SR is carried out at high pressures i.e., 15-35 atm) because much of the H2 produced is supplied in ammonia and methanol plants where higher pressures facilitate better heat recovery and result in compression energy savings." ... 

---