Methanol plant, operating

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. 

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. 

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. 

Most methanol plants operating before 1965 were small, producing about 150 tonnes per day at 250-260 bar pressrae. The small catalyst volume of up to 4.5-... 

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). 

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... 

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). 

The two main sources of air pollutants that may be emitted from basic wastewater treatment plant operations are pulping condensates and bleach plant effluent. The pulping condensates may include total reduced sulfur (TRS) compounds as well as volatile organic compounds (VOCs) such as methanol. The primary pollutants of concern for the bleach plant effluent are chloroform and methanol. Any volatile compounds that could be released as air emissions from basic wastewater treatment plant operations are relatively minor and are generally not subject to specific regulation.65-66... 

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... 

Engineering Construction Industrial Plant Design Development Energy Methanol Equipment Power Systems Manufacturer Cogeneration Electric Plant Operation Independent Power Plant Operation Renewable Energy Technology Fluidized Bed Conventional Boilers... 

The indirect liquefaction processes include Fischer-Tropsch and coal to methanol. Both processes have operated on a commercial scale. For the past 25 years, a Fischer-Tropsch facility has operated in South Africa. Presently the South Africans are constructing an advanced and larger facility. Coal-to-methanol plants existed in the United States, but were replaced by natural gas-to-methanol facilities because it was more economical to do so. 

STD of refined methanol to the US Federal Grade AA specification. The unit is based on natural gas feedstock and was the first plant operating under low carbon concept conditions, i.e., carbon dioxide addition to improve the stoichiometry of the synthesis gas is not required. This unit is based on centrifugal compression throughout and includes three distillation columns. 

Table 4.17 shows that column 2 operates with efficiency as low as 4.1%, while the efficiency of column 1 is 50.6%. The exergy values for the whole separation system of two columns are also low and need to be improved. The individual values of PI show that it is possible to reduce by 13.1% the total loss of 0.834 MW in column 1 and by 19.1% the total loss of 27.813 MW in column 2. Despite the heat integration, the separation section of the methanol plant performs poorly in utilizing the exergy in the distillation columns. 

Example 4.32 Column grand composite curves in methanol plant Table 4.16 describes the existing base case operations for columns 1 and 2 of the methanol plant obtained from the converged simulations using the RKS equation of state to estimate the vapor properties. The activity coefficient model, NRTL, and Henry components method are used for predicting the equilibrium and liquid properties. 

Commercial plants Thirty-five methanol plants have been built using Lurgi s Low-Pressure methanol technology. One MegaMethanol plant is in operation, two are under construction and three MegaMethanol contracts have been awarded with capacities up to 6,750 mtpd of methanol. 

Technology status From January 2002 until March 2004, a demonstration unit was operating at the Statoil methanol plant at Tjeldbergodden, Norway. This unit has confirmed the lab results. The catalyst is commercially available. Lurgi offers the process on commercial terms. 

In the war years, Heuser also undertook the project of building units for converting sulflte spent liquor into alcohol, as well as a pilot-plant operation for the production of methanol, acetone, and other products by the Rinman process. Certain of his experiences were published, even while the war was still in progress. 

Other chemicals operations are in Sarawak. Offshore gas feeds a large methanol plant (660 kt/y) on Labuan Island and an ammonia plant at Bintulu. Also at Bintulu is the large Shell Gas to Liquids plant, which produces high valued linear-paraffins and wax as by-products. The naphtha fraction from the GTL plant is used as petrochemical naphtha. 

A typical long-term average traded price for methanol is in the vicinity of 150/tonne. For this, gas prices have to be below 2/GJ and preferably in the vicinity of 1/GJ. At this time, a typical traded price of gas is in the range of 5/GJ and this has stressed many operations which are force to pay this price. For this reason new gas-based world scale methanol plants have migrated to regions of low gas prices in the Middle East. 

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