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C207 Methanol Catalyst Instruction Manual C207-G High-Pressure Methanol Catalyst I. Purpose: C207 is suitable for methanol synthesis at medium pressure (10–15 Mpa) in the hydroformylation process used in ammonia synthesis; it can also be used for methanol synthesis at medium pressure in the monoalcohol process. C207—G, suitable for high-pressure (15–32 Mpa) methanol synthesis in the production of diols for the ammonia synthesis process. II. Chemical composition and physical properties of the catalyst. 1. Chemical composition: It is mainly composed of oxides of copper, zinc, and aluminum; C207—G also contains small amounts of precious metal additives. 2. Physical properties: Appearance: Black cylinder with a metallic luster. Dimensions: Ø5×5±0.5 and Ø9×6±0.5. Bulk density: C207, 1.4–1.6 kg/L ； C207—G 1.4—1.7 kg/L Radial compressive strength: C207≥145 N/Cm ； C207—G≥240N/Cm ； Ø9×6 (large particles) ≥340 N/Cm; specific pore volume: ~0.16 L/kg; specific surface area: ~70 m2/g; main pore radius: 20–80 Å; average pore radius: ~47 Å. III. Technical specifications of the catalyst: Its activity is measured after reduction under proprietary test conditions. Pre-heat resistance activity: CO conversion rate ≥ 81%. Activity after 5 hours of exposure at 450°C: CO conversion rate ≥ 60%. Operating temperature range: 200–300°C; recommended operating temperature: 220–280°C. Operating space velocity: <20,000 h⁻¹; recommended space velocity: 8,000–12,000 h⁻¹. Substances toxic to the catalyst: sulfur, chlorine, ammonia and their compounds, oils, and carbonyl compounds. IV. Key points to note during the transportation, storage, and loading of the catalyst: 1. The catalyst contains a small amount of physical water, but it is still highly susceptible to absorbing moisture as well as harmful substances such as chlorine, ammonia, and sulfur from the air; therefore, it must be stored in a properly sealed condition. 2. Screening must be carried out before filling: As the catalyst may get broken and fine powder may be generated due to handling, vibration, and dropping during transportation, it is necessary to prevent these fragments from entering the tower. 3. When screening, avoid the inclusion of dust (silica) and metal debris in the catalyst. 4. Catalyst loading is strictly prohibited in rainy or humid weather. 5. When loading the catalyst, it should be distributed evenly inside the tower to avoid spillage from high heights. A cloth bag can be used for guidance if necessary. After the catalyst is loaded, it should be covered and sealed to prevent moisture absorption and gas contamination. 6. After filling is complete, avoid keeping the catalyst under a certain hydrogen partial pressure (reducing gas) for an extended period of time, to prevent the catalyst from being damaged due to automatic heating. V. Temperature-induced reduction of the catalyst: This catalyst is supplied to the user in its oxidized state, and it must be activated by reduction with hydrogen before it can be put into use. If a properly activated catalyst comes into contact with air or is exposed to it, it will burn rapidly. Under normal reduction conditions, among copper, zinc, and aluminum catalysts, only copper oxide is reduced; zinc and aluminum oxides are not reduced. The reduction of copper oxide is an exothermic reaction, and under certain conditions its reaction rate increases rapidly. Under high-hydrogen reduction conditions, it is extremely easy for the catalyst to be damaged if out of control, and its activity after reduction is very poor. 1. Reduction reactions of copper oxide: CuO + H2 → Cu + H2O + 86.6 KJ/mol; CuO + CO → Cu + CO2 + 125.7 KJ/mol. As can be seen from these equations, CO can also be used to reduce CuO, and the amount of heat released during this reduction is one-third higher than that when using H2, making it more difficult to control the temperature. Furthermore, the presence of CO facilitates the formation of metal carbonyl compounds, which poisons the catalyst that has been well reduced and reduces its activity; therefore, the gas medium used for temperature-induced reduction should be free of CO and other substances toxic to the catalyst. It is recommended that during the heating and reduction phase, the feed gas and the gas after alcohol treatment be isolated using blind flanges. Heating reduction is generally carried out using hydrogen, nitrogen (high-hydrogen reduction), or pure nitrogen with hydrogen (low-hydrogen reduction). The amount of water produced during reduction is approximately 20% of the total catalyst amount; it consists of free water, crystalline water, and chemical water generated by the reduction reaction. At a certain space velocity, the reduction process of the catalyst is strictly controlled using the temperature increase curve provided by our company, so as to achieve the best activity for the catalyst. Users are also advised to calibrate the temperature display device before carrying out the heating and reduction process, in order to obtain more accurate temperature readings. 2. Technical parameters for reduction: High hydrogen reduction space velocity: 3000–5000 h-1 ； When it is not greater than 10,000: -1. Low-hydrogen reduction space velocity: 1,500–3,000 h^-1. Water vapor concentration in the gas leaving the tower: controlled at 2 g/m3. Limit value: 4 g/m3. During high-hydrogen reduction, when the water exits at low temperature and the temperature inside the tower is low, the analysis of water vapor concentration may be inaccurate; in such cases, it is possible to refer to the water output per hour or every half hour. The water output corresponding to the water vapor concentration can be determined by the user based on the circulation volume during reduction. For example, during reduction, if two 4 m3/min circulation pumps are used at full capacity with an operating pressure of 5 Mpa, then the water output rate corresponding to a water vapor concentration of 2 g/m3 per hour is: 4×2×60×50×2÷1000 = 48 kg/h. If weighing is done every half hour, the amount of water released in that period is 24 kg per half hour. 3. High-hydrogen reduction operation: (1) The gas source should be pure hydrogen or nitrogen; fresh gas from the ammonia synthesis unit can be used. The system is designed to keep the oxygen content below 0.2%, and it can be pressurized up to 5 Mpa. (2) Maintain a stable reduction pressure; 5 Mpa is generally appropriate, and the configured circulation pump should operate at full capacity. Calculate the space velocity based on the circulation rate and catalyst volume, and select the corresponding temperature rise and reduction curve. (3) The heating phase can be carried out at a rate of 10–15°C/h, but attention must be paid to the temperature difference within the bed; if this difference is large, the rate should be reduced. (4) Within the range of 65–75°C, try to determine the initial reduction temperature; reduce the heating rate by 2–3°C. Pay attention to the following: once the power of the electric furnace and the temperature of the bed layer reach equilibrium, if the temperature in the upper layer starts to rise, it is necessary to reduce the furnace’s power in order to maintain stability, and water vapor will then be released ； When the water vapor concentration rises and the alcohol begins to release water, it is considered that the catalyst in that furnace has started to reduce. Maintain the temperature at this level for a period of time before moving on to the next stage. (5) The initial reduction temperature is –110°C, marking the start of the reduction phase; the rate of temperature increase is 0–3°C/h. During this phase, the amount of water produced typically accounts for about 50% of the total water output (see “Notes”). The appropriate temperature increase curve for reduction can be selected based on the reduction space velocity, and the temperature should be increased according to that curve. If the deviation curve increases the heating rate, it will lead to loss of control and a \"temperature spike.\" This is the critical stage of reduction, and it is also the stage most prone to getting out of control. Be sure to pay attention. (6) 110–140°C: During this stage, the removal of free water occurs; there is virtually no increase in temperature, indicating that the reduction reaction of CuO is essentially complete. The temperature can only be maintained or increased by using heat supplied by an electric furnace. Control is achieved by increasing the furnace power according to the temperature rise curve, with a temperature rise rate of 3–5°C/hr. (7) 140–180°C. The water output has increased again, with virtually no rise in temperature; heat is supplied by an electric furnace to maintain and raise the temperature. The main goal is to remove the crystalline water, and control is continued according to the established curve, with a temperature increase rate of 2–4°C per hour. (8) 180–240°C: During this stage, the amount of water released is very small; the main objectives are complete reduction and minimizing the temperature difference. The rate of temperature increase is 5–8°C/hr. (9) Maintain a constant temperature of 240°C for two hours; if the temperature difference is large, the rate of temperature increase can be reduced to extend the time. Reduction is complete; cool down to 220°C. After installing the blind flanges, the operation is shifted to light load conditions (with a lower CO content of 2–3% and a lower space velocity of 5000–6000 h⁻¹, taking advantage of the self-heating effect during synthesis), and production continues for 1–2 days; thereafter, the load is increased and normal operation resumes. (10) If the temperature rises out of control during the reduction process, the following action can be taken: turn off the furnace ； Kaita bypass line ； Vent after depressurizing and opening the tower. (11) For processes with a rear-mounted boiler, care should be taken to ensure that steam is not used to preheat this boiler until the temperature at the tower outlet reaches 100°C; alternatively, an alternative route can be used to direct the gas leaving the tower away from the boiler, thereby preventing the introduction of external heat sources during the catalyst reduction process in the synthesis tower and avoiding unintended loss of control over this reduction process. When the outlet temperature of the synthesis tower reaches 100°C. At this point, the reduction of copper oxide in the catalyst layer is nearly complete, and preheating the boiler with steam prior to putting it into operation will not cause the temperature in the catalyst layer to get out of control. (12) The legend for the temperature rise reduction curve is provided later; the time required for each stage at various space velocities is given in hours. Space Velocity, Stage Temperature (°C): 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500. Temperature rise rate (°C/h): Room temperature–70: 4, 4, 4, 4, 4, 4, 4, 4, 4; 10–15: 70–110: 50, 40, 34, 30, 26, 22, 20, 18; 0–3: 110–140: 14, 12, 10, 9, 8, 8, 7, 7; 3–5: 140–180: 26, 20, 16, 15, 14, 14, 13, 12; 2–4: 180–240: 14, 12, 10, 9, 8, 8, 8, 8; 5–8: 240: 2, 2, 2, 2, 2, 2, 2, 2; 0: 240–220: 2, 2, 2, 2, 2, 2, 2, 2; –10. Total: 112, 92, 78, 71, 64, 60, 56, 53. file:///E:/DOCUME~1/zzjjaa/LOCALS~1/Temp/ksohtml/wps_clip_image1.png Note: During the reduction process, water discharge from the alcohol component is measured every half hour as a reference indicator for reduction. However, due to differences in the layout and design of the water coolers, water accumulation may occur inside them, which can affect the accuracy of this measurement. 4. Low-hydrogen reduction process. (1) The heating medium is pure nitrogen (with an O2 content of less than 0.2%); if nitrogen from gas cylinders is used, each cylinder must be analyzed to ensure that the O2 content is below 0.2%. First, perform system displacement to reduce the O2 content to <0.2%, then fill it with nitrogen to a pressure of 2–3 Mpa (and up to 5 Mpa if possible), and start the circulation pump to raise the temperature. (2) Room temperature to –130°C, with a temperature increase of about 15°C/hour, to remove free water. Start releasing water at 100°C; when the temperature difference is large, the heating rate can be reduced. The air velocity is at -1 in the range of 1500–3000, and the water vapor concentration is kept below 4 g/m3. (3) Maintain a constant temperature of 130°C for more than two hours, depending on the temperature difference and the amount of water discharged; a larger temperature difference, greater water discharge volume, and higher water vapor concentration allow for an extended period of constant temperature. (4) During the hydrogenation reduction stage at 130–160°C, the principle to follow is to carry out hydrogenation at a constant temperature or increase the hydrogen content; raising the temperature should not be done without increasing the hydrogen content. After the constant temperature of 130°C is reached, hydrogenation begins, or clean hydrogen and nitrogen are used to ensure that the hydrogen content in the circulating gas inside the tower is ≤0.5%. It is necessary to monitor whether there is an upward trend in the temperature at the upper level, as well as whether the amount of water released increases. If the temperature rises, the power of the electric furnace can be reduced to maintain a constant temperature. The water vapor concentration should be between 2–4 g/m3; if it is below 2 g/m3, the amount of hydrogen added can be increased slightly, while if it approaches 4 g/m3, the amount of hydrogen added should be reduced. Adjustment can also be made by referring to the water discharge volume; the hourly water discharge amount can be calculated based on the circulation capacity of the circulators. For example, with a pressure of 2.5 Mpa, two circulators with a capacity of 4 m3/min each, and a water vapor concentration of 2 g/m3, the water discharge volume would be: 4×2×60×25×2÷1000 = 24 kg/h. If the concentration is 4 g/m3, then it would be 48 kg/h. During hydrogenation, the hydrogen content should be analyzed continuously and should be <1%. If there are no abnormalities, hydrogen can be continuously supplied, and the temperature can be increased at a rate of 2–3°C per hour. By the end of this stage, the cumulative water output should account for about 80% of the total water output. (5) 160–200°C, with a heating rate of 5–8°C/h; the temperature is increased and the hydrogen supply is enhanced depending on the water vapor concentration and the amount of water released. When the water vapor concentration is below 1 g/m3, the temperature can be raised simultaneously while increasing the amount of hydrogen added. As the hydrogen content increases and the amount of circulating gas entering the tower reaches 3–4%, the temperature rise is not significant. If more power from the electric furnace is required to raise the temperature, the system pressure can be increased to 5 Mpa; in this case, the hydrogen concentration is no longer a constraint, and attention is focused instead on the water vapor concentration and the corresponding water output. At this stage, at 180–200°C, the water vapor concentration decreases and the water output decreases as well. When the temperature difference is large, a constant temperature should be maintained. (6) 200–240°C. The heating rate is 5–10°C/hr; once the water vapor concentration drops below 0.2 g/m3, the amount of hydrogen added, or the combination of hydrogen and nitrogen, is increased further. Maintain a temperature of 240°C for more than two hours; as the pressure increases, the air supply volume of the circulator can be gradually reduced to keep the bed layer at a constant temperature. Reduction completed. (7) Cool down to 220°C at a rate of 10°C per hour, turn off the furnace, stop the circulation pump, relieve pressure and remove the blind flange, then switch to light-load operation. (As with the high-hydrogen reduction method), normal production is resumed after 1–2 days once the load is applied. (8) If the temperature rises out of control during the reduction process, the following action can be taken: stop hydrogenation ； Cutting furnace ； Increase circulation volume, activate tower side line ； Finally, the system is depressurized and pure nitrogen is added. VI. Normal operating and usage conditions 1. Temperature: The optimal operating temperature for C207 and C207—G is 240–280°C. It exhibits significant activity at 220°C. In industrial applications, in order to ensure a long service life for the catalyst, and provided that the production volume and the quality of the alcohol-containing gas meet the requirements of subsequent processing stages, it is advisable to operate at lower temperatures as much as possible, avoiding unnecessary increases in temperature. The synthesis of methanol is an exothermic reaction: CO + 2H2 → CH3OH + 90.6 KJ/mol; CO2 + 3H2 → CH3OH + H2O + 49.4 KJ/mol. Apart from the main reaction, there are multiple reaction pathways, and the main by-products include alkanes, esters, alcohols, higher alcohol ethers, acids, etc.; therefore, it is important to maintain a uniform temperature in the catalyst layer. When the temperature difference is large, causing the temperature of some of the catalysts to drop below 210°C or rise above 300°C, the catalyst’s selectivity for methanol synthesis decreases, side reactions increase, the quality of crude methanol deteriorates and even waxing occurs, leading to an increase in resistance in the equipment. The catalyst itself has poor thermal conductivity, resulting in a certain delay in changes in reaction temperature. Improper operation that leads to large temperature fluctuations can cause localized overheating of the catalyst; meanwhile, operating it at high temperatures for an extended period can damage the separators between zinc oxide particles in the catalyst. This accelerates the growth of active copper grains, resulting in the loss of the active surface and thus deactivating the catalyst, causing it to \"age\" and have its lifespan shortened. For temperature control, the operator should identify the sensitive point of the bed temperature as a basis for operation in order to ensure stable performance. 2. Pressure: The synthesis of methanol is a volume-reducing reaction; increasing the pressure is favorable for the equilibrium. A higher pressure raises the partial pressures of the reactants, accelerating the reaction and increasing the CO conversion rate. Therefore, although C207—G has copper and zinc contents similar to those of C207, its unique strength and improved manufacturing process make it particularly suitable for high-pressure glycol blends. 3. Operating space velocity: For the production of diols, the gases that enter the catalyst are only limited amounts of CO, CO2, and the corresponding H2, which participate in the reaction; most of the H2 and N2 gases do not participate in the reaction but simply pass through the catalyst while carrying away the heat generated by the reaction. Therefore, to maintain heat balance, the air velocity cannot be too high. In the production of diols, the yield of methanol is determined by the overall material balance of the plant, as well as the concentration of CO entering the catalyst and its conversion rate. Therefore, the space velocity performance of this catalyst meets the high space velocity requirements under test conditions and is not suitable for industrial use; our company recommends a space velocity of 8000–12000 h⁻¹. Too low a space velocity leads to uneven gas distribution and an increased temperature difference within the bed, while too high a space velocity increases the resistance in the components of the synthesis tower; this causes the catalyst to be washed away, pulverized, and even carried into subsequent systems, affecting the quality of crude methanol. At the same time, if the space velocity is too high, the accumulation of toxins brought in with the process gas increases proportionally, causing the catalyst to become poisoned and deactivated, thereby shortening its service life. Too high an air velocity reduces the residence time on the catalyst, resulting in a decrease in CO conversion rate. Once a stable state is achieved by using a bypass line for adjustment and regulating the inlet temperature based on the CO content, the space velocity should be reduced as much as possible, the circulation volume should be minimized, and space velocity fluctuations should be avoided. C207—G, which is used in high-pressure methanol synthesis, can allow the space velocity to be increased appropriately to 10,000–15,000 h⁻¹. 4. Control of the components in the gas entering the reactor: (1) Control of CO content in the fresh gas – The CO content in the fresh gas is the main factor used to adjust the methanol production level; higher CO levels result in higher methanol production. Reasonable control of the CO content in the fresh gas is an important factor for the economic operation of hydroxymethanol production, and it is adjusted based on several factors: the proportion of methanol production in the total ammonia production; when the CO conversion rate is high, the level of CO content directly affects the amount of methanol produced ； It also affects the ammonia synthesis yield; an excessively high alcohol-to-ammonia ratio reduces the hydrogen-to-carbon ratio entering the reactor, thereby increasing the side reactions in the synthesis process ； The CO content in the gas after alcohol treatment: when the CO conversion rate and the flow rate remain constant, any change in the CO content in the fresh gas directly affects the CO content in the gas after alcohol treatment, thereby impacting the normal operation of the purification unit for this gas ； The hydrogen-to-nitrogen ratio in ammonia synthesis. It should be considered comprehensively based on the activity level of the catalyst. (2) Control of methanol content in the gas entering the tower: Methanol in the gas entering the tower is brought in by the recycled gas. A high methanol content in this gas not only affects the reaction equilibrium in methanol synthesis, leading to a decrease in CO conversion rate, but it also increases side reactions, causes wax formation in the system, leads to catalyst degradation, and results in catalyst poisoning. The methanol concentration in the gas entering the tower is almost directly proportional to the rate of formation of the by-product dimethyl ether, resulting in an increased dimethyl ether content in the gas leaving the tower; this can even lead to poisoning of the ammonia synthesis catalyst. Therefore, the methanol content in the gas entering the tower should be as low as possible; the water cooling temperature must not exceed 30°C. The alcohol separation unit must ensure effective separation to prevent methanol from being carried in the recycled gas. Where possible, the ratio of recycled gas to fresh gas should be reduced, as this helps to lower the methanol content in the gas entering the tower. (3) Control of CO2 content: The presence of CO2 in the gas entering the tower reduces the intensity of the methanol synthesis reaction, but it increases the consumption of H2 gas and raises the water content in the crude methanol. This should be determined by a comprehensive assessment of factors such as the factory’s decarbonization effects. A CO2 content of 0.5–1.0% can be considered. (4) Effect of toxic impurities in the feed gas on the catalyst A. Sulfur and sulfides Sulfur and its compounds in the feed gas, such as H2S, CS2, and COS, readily react with the active components copper and zinc in the catalyst, causing phase changes and resulting in catalyst deactivation. 2Cu + H2S = Cu2S + H2; ZnO + H2S = ZnS + H2O. The total sulfur content in the feed gas must be reduced to less than 0.1×10-6. Catalyst poisoning can be minimized; in the production of glycol, a desulfurization unit operating at normal temperature must be in place after decarburization to protect the catalyst. B. Chlorine and chlorides: Chlorides not only poison the copper crystals; the resulting CuCl has a low melting point and high surface mobility, which accelerates the sintering of the catalyst surface. Moreover, it reacts with zinc oxide in the catalyst to form low-melting-point ZnCl2, leading to further poisoning and sintering of the catalyst, thereby rapidly reducing its activity and causing an increase in side reactions as well as severe coking. Its toxicity is 10 times greater than that of sulfur. It is hoped that users will first start by addressing the source of chlorine and chlorides to prevent their inclusion in the feed gas ； Second, a dechlorinating agent is added to the precise desulfurization unit to reduce the chlorine and chloride content in the feed gas to less than 0.1×10-6. C. Carbonyl metal compounds: Under pressure, carbonyl compounds can be formed even in the presence of CO at temperatures of 25–100°C. The higher the partial pressure of CO, the more favorable the conditions for the formation of carbonyl compounds. The corrosion of metals by carbonyls occurs at the fastest rate at temperatures of 150–200°C; the presence of chlorine or sulfur in the gas further accelerates this corrosion. In the production of ferroalloys, corrosion mainly leads to the formation of Fe(CO)5 and Ni(CO)4. Carbonyl metals carried to the catalyst layer decompose easily into highly dispersed iron and nickel particles once heated on the catalyst surface; these particles adsorb and deposit on the catalyst surface, reducing its activity and blocking its pores, thereby causing poisoning and deactivation. It reduces the selectivity of the catalyst, increases side reactions, and causes severe waxing. Users are advised to use a decarboxylating agent. During production, startup, and shutdown processes, try to avoid or minimize the formation of metal carbides. For example: during startup and shutdown, temperature rise occurs; it is not advisable to use gases containing CO as a gas source. During short-term shutdowns, it is absolutely forbidden to keep the furnace under pressure by directly using feed gas containing CO. Based on such experimental data, after maintaining the pressure with the furnace shut down for 12 hours, the CO conversion rate decreased by 26% when the furnace was restarted. D. Ammonia: Even trace amounts of ammonia in the gas can directly affect the initial activity of the catalyst as well as its service life; therefore, the ammonia content in the feed gas must be reduced to 0.5×10-6. The introduction of ammonia causes the catalyst to form copper-ammonia complexes, resulting in its deactivation. During the synthesis process, an amination reaction occurs, producing methylamine as a byproduct which affects the quality of methanol. When the raw gas contains 50×10-6–100×10-6 of ammonia, it can reduce the catalyst’s activity by 10–20%. Users can remove ammonia using water washing and ammonia-removing agents. E. Oil contamination: Oil is carried to the catalyst along with the feed gas; it not only causes carbon and high-carbon substances to deposit, leading to the blockage of the catalyst’s pores and the coverage of its active surface, but the organic sulfur in the oil also directly poisons the catalyst, while the thermal decomposition of the oil results in the fragmentation of the catalyst. Users need to improve the efficiency of oil separation to prevent oil and water from entering the tower. VII. Maintenance of catalysts to extend their service life 1. During normal production, the frequency of load fluctuations should be reduced; when adjusting the bed temperature, its lagging effect must be taken into account, and adjustments should be made in advance to minimize temperature fluctuations. 2. Make full use of the initial high activity of the catalyst; avoid raising the temperature at the hot spots in the bed easily, provided that production requirements are met. It is advisable to increase the temperature by 3–5°C each time as per the temperature control criteria. 3. The pressure increase and decrease rates of the synthesis tower must be strictly controlled at 0.5 Mpa/min. Never relieve pressure in front of the tower; this is to prevent the catalyst powder from becoming fragmented and the internal components from being crushed as a result of too rapid pressure release. The catalyst powder should be poured into the cold tube or the central tube. 4. When parking the system for a short period of time, it is not advisable to use raw gas to maintain pressure in the furnace; instead, clean H2 or N2 gas can be used for purging, or the circulation pump can continue to operate along with the electric furnace to keep the bed temperature such that the CO level in the gas is close to zero, after which the circulation pump can be stopped. For parking for more than 24 hours, if the methanol synthesis unit is shut down separately, the feed gas and the gas after alcohol formation should be isolated using blind flanges. The pressure should be reduced and the temperature lowered to below 200°C, with a positive pressure of 0.1–0.2 Mpa maintained; when gas needs to be added to maintain this positive pressure, it should be introduced in a forward direction. The activated catalyst burns and becomes deactivated upon exposure to air, so it must be under constant supervision during shutdown periods. 5. Clean H2 and N2 gases should be used for heating during driving. 6. When replacing the catalyst, be sure to drain all of the old catalyst. If oil contamination is found on the walls of the internal components, the oil must be removed from those components (including the heat exchanger section) before a new catalyst can be installed.