TW201425229A - Variation of ammonia ratio in Andrussow process - Google Patents

Abstract

Methane and ammonia raw materials are typically the major costs for HCN production. The methods described herein can be used to vary the molar ratio of methane to ammonia during HCN production to reduce costs.

Description

Change in ammonia ratio in the ANDRUSSOW method Cross-reference to related applications

This application claims priority to U.S. Provisional Patent Application Serial No. 61/738,727, the entire disclosure of which is incorporated herein in .

This invention relates to a feed composition for the Andrussow process which produces hydrogen cyanide (HCN) from methane, ammonia and oxygen.

The Andrussow process converts ammonia and methane gas to hydrogen cyanide (HCN) in the presence of oxygen and platinum catalysts. The reaction is as follows: 2NH ₃ + 2CH ₄ + 3O ₂ → 2HCN + 6H ₂ O

Typically ammonia (NH _3), methane (CH ₄₎ and a source of oxygen (e.g., air) fed into the reactor and heated up to a temperature of about 2,500 deg.] C in the presence of a catalyst of platinum or a platinum alloy.

The availability and price of reactant gases such as methane and ammonia significantly affect the profit from the manufacture of HCN products. For example, the raw material cost of Andrussow methane and ammonia reactants can be greater than 90% of the total HCN variable cost.

Although many factors can affect the price of ammonia, historically, ammonia prices have largely depended on demand. Ammonia is used for a variety of purposes and most (about 80%) consume fertilizer used in agricultural manufacturing material. Strong demand for agricultural products can keep ammonia prices high.

Methane prices have also changed for a variety of reasons, but most of the volatility is related to the availability of natural gas supplies. In recent years, the Yeyan gas revolution has significantly reduced the price of natural gas. For example, since 2011, the price of natural gas has fallen by about 45%. According to the U.S. Energy Information Administration (EIA), the international list has also increased by 56% last year. However, when other sources of energy become less available or environmental problems reduce the use of coal and oil, the large amount of natural gas can no longer be used. The energy market can gradually shift to natural gas.

As a result, manufacturers have ongoing problems with the manufacture of hydrogen cyanide, which continues to be profitable even if the price of key reactants changes and is unpredictable.

The various aspects of HCN manufacturing are described in the following articles: Eric.L.Crump, US Environmental Protection Agency, Office of Air Quality Planning and Standards, Economic Impact Analysis For the Proposed Cyanide Manufacturing NESHAP (May 2000), available at http: //nepis.epa.gov/Exe/ZyPDF.cgi? Dockey=P100AHG1.PDF is available online for the manufacture, end use and economic impact of HCN; NVTrusov, Effect of Sulfur Compounds and Higher Homologues of Methane on Hydrogen Cyanide Production by the Andrussow Method , Rus. J. of Applied Chemistry, Vol. 74, No. 10, pp. 1693-97 (2001), which deals with the effects of the inevitable components of natural gas (such as high homologues of sulfur and methane) on HCN manufactured by the Andrussow process; Clean Development Mechanism (CDM) Executive Board, United Nations Framework Convention on Climate Change (UNFCCC), Clean Development Mechanism Project Design Document Form (CDM PDD) , 3rd Edition, (July 28, 2006), available at http:// Cdm.unfccc.int/Reference/PDDs_Forms/PDDs/PDD_form04_v03_2.pdf is available online for HCN manufacturing by Andrussow method; and Gary R. Maxwell et al., Assuring process safety in the transfer of hydrogen cyanide manufacturing technology J. of Hazardous Materials, Vol. 142, pp. 677-84 (2007), which is for the safe manufacture of HCN.

The higher and variable cost of HCN manufacturing is solved or improved by operating the HCN reaction at a regulated (eg, atypical) ammonia:methane ratio based on natural gas (eg, methane) and ammonia prices. Proactive and ongoing assessment of natural gas and ammonia prices and ammonia: methane ratio adjustment during HCN manufacturing can significantly reduce costs.

In general, manufacturers strive to control costs by using resources in the most efficient way. During the Andrussow process, efficient conversion of methane and ammonia to hydrogen cyanide typically involves setting the ammonia:methane ratio in the reaction mixture to optimally convert the reactants to produce the most HCN. For example, the manufacturer may choose to adjust the ammonia:methane ratio during the Andrussow process to bring the methane feed stream in the reactor to approximately 100% or less. These Andrussow methods are usually operated efficiently. However, the Andrussow reaction can tolerate some ammonia: methane ratio changes and still operate efficiently. Ammonia and methane can be the main operating costs of the Andrussow process. As described herein, active monitoring of ammonia cost versus methane cost (and vice versa) can be employed to reduce HCN manufacturing costs, particularly in view of their cost assessment combined with adjustment of the ammonia:methane ratio. The assessment of the market cost of ammonia and methane can be used to establish an appropriate ammonia:methane ratio while still achieving an astonishingly efficient conversion of Andrussow reactants to products.

This paper describes ways to increase the value in a hydrogen cyanide manufacturing facility, which involves: (a) assessing the cost of obtaining methane and ammonia; and (b) adjusting the feed to the reactor for the production of hydrogen cyanide. The ratio of ears, thereby using the adjusted molar ratio of methane to ammonia and thereby increasing the value in the hydrogen cyanide manufacturing facility.

Increasing the value in a hydrogen cyanide manufacturing facility can, for example, include reducing the unit cost of hydrogen cyanide production in the facility, reducing the unit cost of methane or reducing the unit cost of ammonia. Every day Or estimate the cost of methane and ammonia per week to increase the value in the hydrogen cyanide facility.

The adjusted methane to ammonia molar ratio can vary, for example, from about 0.6 to about 1.1. After adjusting the market cost of methane and ammonia over time, the adjusted ratio can be re-adjusted repeatedly.

The methane to ammonia molar ratio can be adjusted when the ammonia cost is increased or decreased relative to the average ammonia cost noted during the selected period of operation of the hydrogen cyanide manufacturing facility. For example, the methane to ammonia molar ratio A fed into the reactor may range from about 0.6 to about when the ammonia cost is reduced relative to the average ammonia cost noted during the selected period of operation of the hydrogen cyanide manufacturing facility. Within the range of 0.9. However, when the ammonia cost is increased relative to the average ammonia cost noted during the selected period of operation of the hydrogen cyanide manufacturing facility, the methane to ammonia molar ratio B fed to the reactor may also be between about 0.75. In the range of about 1.0, the methane to ammonia molar ratio A can be lower than the methane to ammonia molar ratio B.

The adjusted methane to ammonia ratio can be employed, for example, when ammonia is relatively inexpensive, it has an increased molar amount of ammonia compared to the amount of methane. This "ammonia-rich" ratio can be used, for example, as long as the ammonia price savings are greater than: the additional ammonia recovery cost + the ammonia loss cost + the cost of the sub-optimal HCN manufacturing associated with excess ammonia.

The methane to ammonia molar ratio can also be adjusted when the methane cost is increased or decreased relative to the average methane cost noted during the selected period of operation of the hydrogen cyanide manufacturing facility. For example, the adjusted ratio in the reactor may range from 0.75 to about 1.0 when the methane cost is reduced relative to the average methane cost noted during the selected period of operation of the hydrogen cyanide manufacturing facility. The adjusted ratio may range, for example, from about 0.6 to about 0.9 when the methane cost is increased relative to the average methane cost noted during the selected period of operation of the hydrogen cyanide manufacturing facility.

This ratio can be used when the HCN reaction system is operated with a relatively rich amount of methane, for example, as long as the methane price savings are greater than the impurity cost + methane loss cost + the cost of sub-optimal HCN manufacturing associated with excess methane.

The ammonia fed to the reactor can be kept constant at approximately the set point and evaluated in A After the cost of the alkane and ammonia, the methane fed to the reactor can be varied. Alternatively, the methane fed to the reactor can be held constant at approximately the set point and the ammonia fed to the reactor can be varied after assessing the cost of methane and ammonia.

Several parameters can be used to evaluate the efficiency of HCN manufacture and its use as an indicator of the methane to ammonia ratio can increase the value of HCN manufacturing. For example, the reaction temperature is a measure of the efficiency of the reaction, and higher temperatures may indicate that the reaction proceeds inefficiently. The molar ratio of methane to ammonia can be adjusted, for example, as long as the temperature of the reactor is in the range of from about 1,000 ° C to about 1,300 ° C, or from about 1,050 ° C to about 1,200 ° C. The adjusted methane to ammonia ratio can also be employed as long as the temperature of the reactor is within about 140 ° C of the minimum reaction temperature for selecting the methane to ammonia molar ratio.

Reduced HCN manufacturing can also be a sign of inefficient conversion of methane and ammonia to HCN. For example, a regulated methane to ammonia ratio can be employed as long as the product stream exiting the reactor has at least about 14.5% vol/vol HCN.

The loss of unconverted methane in the product stream can also be an indicator of the inefficient conversion of methane and ammonia to HCN. For example, a regulated methane to ammonia ratio can be employed as long as the product stream exiting the reactor has less than about 2.5% vol/vol of methane.

Similarly, the loss of unconverted ammonia in the product stream can also be an indicator of the inefficient conversion of methane and ammonia to HCN. For example, a regulated methane to ammonia ratio can be employed as long as the product stream exiting the reactor has less than about 8% vol/vol ammonia.

Figure 1 graphically illustrates the percent ammonia yield (the amount of HCN produced per amount of ammonia consumed in the reaction; the dashed line (original yellow triangle)) decreases as the ratio of ammonia to oxygen (e.g., air) increases. However, as also shown in Figure 1, the percent yield of methane (or natural gas, NG; diamond symbols) increases as the ratio of ammonia to oxygen (eg, air) increases, indicating a higher level in the reaction mixture. When ammonia is used, more methane is converted to HCN.

Figure 2 graphically shows the ratio of methane to oxygen at different fixed ammonia to oxygen ratios. The effect on bed temperature.

Figure 3 graphically illustrates the effect of methane to oxygen ratio on percent ammonia conversion at different fixed ammonia to oxygen ratios.

FIG 4 graphically shows acetonitrile (CH ₃ CN) with methane leakage amount of impurity (unreacted methane) is formed of an increase during the Andrussow reaction.

The cost of ammonia relative to methane has generally increased since about 2007. In addition, the volatility of the ratio of their costs has become greater. For example, between January 2001 and July 2007, the wholesale anhydrous ammonia price divided by the individual natural gas price varied between about 40 and 60. See the website at agprofessional.com/resource-centers/crop-fertility/nitrogen/news/132067938.html. Therefore, ammonia is about 50 times more expensive than methane. However, between July 2008 and July 2011, the wholesale anhydrous ammonia price divided by the individual natural gas price varied from about 60 to 150. Cit. Therefore, ammonia is not only more expensive than about 60-150 times, and the relative price volatility of ammonia compared to methane is significantly greater.

As described herein, the problem of increased cost and increased cost variability in HCN manufacturing during the Andrussow reaction can be addressed or improved by varying the methane and ammonia molar ratios as the cost of methane and ammonia changes. Accordingly, a method for increasing the value in a hydrogen cyanide manufacturing facility is described, which involves assessing the cost of methane and ammonia, and adjusting the operating molar ratio of methane to ammonia used to produce hydrogen cyanide to reduce their cost. In general, the Andrussow reactor operates with a lean to molar ratio of methane to ammonia, which means that the amount of methane fed to the reactor is typically less than the amount of ammonia in the ammonia. Therefore, the cost of HCN manufacturing can be more susceptible to ammonia prices and can fluctuate significantly when ammonia prices fluctuate.

Andrussow reaction

As indicated above, the Andrussow process typically converts ammonia and methane to hydrogen cyanide (HCN) in the presence of oxygen and a platinum catalyst. The reaction is as follows: 2NH ₃ + 2CH ₄ + 3O ₂ → 2HCN + 6H ₂ O

The filtered ammonia, natural gas, and oxygen-containing feed stream (eg, air, oxygen-enriched air, or substantially pure oxygen) is fed to the reactor and heated at a temperature of up to 1,500 ° C in the presence of a platinum-containing catalyst. . In general, the temperature of the Andrussow reaction is maintained from about 800 ° C to about 2500 ° C, from 800 ° C to about 1,500 ° C, or from about 850 ° C to about 1,400 ° C, or from about 900 ° C to about 1,300 ° C or about 1,050 ° C to At about 1,250 ° C.

Methane can be supplied from natural gas or a more pure source of methane from which higher hydrocarbons have been removed. Although air can be used as the oxygen source, the reaction can also be carried out using oxygen-enriched air or undiluted oxygen (i.e., oxygen Andrussow method). The reactor off-gas containing HCN and unreacted ammonia is typically quenched in a waste heat boiler at about 100 ° C to 400 ° C. The cooled reactor off-gas is typically passed through an ammonia absorption process to remove unreacted ammonia. This can be accomplished by adding ammonium phosphate solution, phosphoric acid or sulfuric acid to remove ammonia. The product off-gas is passed from the ammonia absorber through an HCN absorber where water is added to draw in the HCN. The HCN-water mixture is then passed to a cyanide stripper where excess waste is removed from the liquid. Alternatively, the HCN-water mixture can be passed through a fractionator to concentrate the HCN, after which the product is stored in a tank or used directly as a feedstock. Waste generated from impure reactants or generated by sub-optimal reaction conditions can result in carbon build-up and settling in the equipment employed during the process. The waste can also cause HCN to polymerize and can form sediment or sludge in the HCN product storage tank.

As indicated above, the Andrussow reaction can employ an oxygen-containing feed stream having a varying oxygen content. Commonly used oxygen-containing feed streams include air, oxygen-enriched air, and substantially pure oxygen. However, other sources may include oxygen enriched air and/or oxygen mixed with an inert gas such as nitrogen or argon. As used herein, the air Andrussow process uses air as the oxygen-containing feed stream, wherein the air has about 20.95 mol% oxygen. The oxygen-rich Andrussow process uses from about 21 mol% oxygen to about 26 mol% oxygen, 27 mol% oxygen, 28 mol% oxygen, 29 mol% oxygen, or to about 30 mol% oxygen, such as about 22 mol% oxygen, 23 mol% oxygen, 24 mol%. Oxygen or about 25 mol% oxygen formed oxygen-containing feed stream. The oxygen Andrussow process uses about 26 mol% oxygen, 27 mol% oxygen, 28 mol% oxygen, 29 mol% oxygen, or about 30 mol% oxygen to about 100 mol% oxygen. Oxygen-containing feed stream. In some embodiments, the oxygen Andrussow process can employ about 35 mol% oxygen, 40 mol% oxygen, 45 mol% oxygen, 50 mol% oxygen, 55 mol% oxygen, 60 mol% oxygen, 65 mol% oxygen, 70 mol% oxygen, 75 mol% oxygen. An oxygen-containing feed stream of 80 mol% oxygen, 85 mol% oxygen, 90 mol% oxygen, 95 mol% oxygen, or about 100 mol% oxygen.

In various examples, an oxygen-enriched Andrussow process or an oxygen-containing feed stream in an oxygen Andrussow process having an oxygen-containing feed stream of less than 100 mol% oxygen can be generated by at least one of the following: The mixed air is combined with oxygen, mixed oxygen and any suitable gas or gas or from an oxygen-containing gas (eg, air) to remove one or more gases.

Synthesis of hydrogen cyanide by the Andrussow process (see, for example, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 8, VCH Verlagsgesellschaft, Weinheim, 1987, pp. 161-162) may be via the inclusion of platinum or platinum alloys or other gases in the gas phase. Metal catalyst implementation. Catalysts found to be suitable for the implementation of the Andrussow process are described in the original Andrussow patents and elsewhere as disclosed in U.S. Patent No. 1,934,838. In the original work of Andrussow, it is disclosed that the catalyst can be selected from an oxidizing catalyst that does not melt (solid) at an operating temperature of about 1000 °C. For example, Andrussow describes a catalyst that can include platinum, rhodium, ruthenium, palladium, iridium, gold or silver as a catalytically active metal in pure form or as an alloy. It is also noted that certain barium metals, such as rare earth metals, cerium, uranium and others, may also be used, for example, in the form of infusible oxides or phosphates, and it is noted that the catalyst may be formed into a mesh (mesh) or deposited on Heat resistant solid support (such as vermiculite or alumina).

In subsequent research and development work, platinum-containing catalysts have been selected for their effectiveness and even the heat resistance of metals in the form of mesh or mesh. For example, a platinum-rhodium alloy can be used as the catalyst, which can be in the form of a wire mesh or mesh, such as a woven or knitted mesh sheet, or it can be disposed on a carrier structure. In an example, the woven or knitted mesh sheet can be formed into a mesh structure having a mesh size of 20-80, for example, having an opening of about 0.18 mm to about 0.85 mm. The catalyst may comprise from about 85 wt% to about 95 wt% Pt and from about 5 wt% to about 15 wt% Rh, such as 85/15 Pt/Rh, 90/10 Pt/Rh or 95/5 Pt/Rh. Platinum-ruthenium catalysts may also contain small amounts of metallic impurities. For example, iron (Fe), palladium (Pd), iridium (Ir), ruthenium (Ru), and other metals. The impurity metal may be present in trace amounts (e.g., about 10 ppm or less).

Further information on the Andrussow process is described in German Patent 549,055. In one example, a catalyst comprising a plurality of fine-grained screens of 10% bismuth Pt arranged in series is used at a temperature of from about 800 °C to 2,500 °C, from 1,000 °C to 1,500 °C, or from about 980 °C to 1050 °C. For example, the catalyst may be a commercially available catalyst such as Pt-Rh catalyst mesh available from Johnson Matthey Plc, London, UK or Pt-Rh catalyst filament available from Heraeus Precious Metals GmbH & Co., Hanau, Germany. network.

Changing the reactant molar ratio as the reactant cost changes

Methane and ammonia reactants are typically the major cost of HCN manufacturing. For example, more than 90% of the total HCN variable cost is typically consumed by methane and ammonia. Other costs, such as steam and electricity, typically account for less than about 10% of the total cost. Described herein are methods that involve considering the relative cost of ammonia versus methane (and vice versa) to alter the ratio of such high cost reactants and thereby reduce overall HCN manufacturing costs.

The optimal reaction conditions for the Andrussow process are variable. The variables affecting the output of HCN include not only the methane to ammonia ratio, but also the purity of the reactants, the type of catalyst, the activity of the catalyst, the life of the catalyst, the reaction temperature, the feed rate, the presence of by-products, and the reaction mixture. Uniformity and other factors. The ratio of methane to ammonia can be altered or optimized to accommodate these factors. However, according to the methods described herein, the cost of methane and ammonia can be evaluated to initiate other variations in the methane to ammonia molar ratio and thereby reduce cost while still maintaining good HCN output.

The feed to the Andrussow process is usually "depleted in methane" operation, which means that the feed in the reactor usually contains less methane than ammonia. For example, the appropriate molar ratio of methane to ammonia in the Andrussow reaction being carried out under fairly normal operating conditions can range from about 0.8 to about 0.9, but can be lower during startup or when operating under very useful conditions. The methods described herein involve assessing the cost of methane and ammonia reactants, and subsequently adjusting methane to ammonia in view of this cost estimate. Mo ratio. Thus, the molar ratio of methane to ammonia can then vary beyond normal operating conditions of from about 0.8 to about 0.9.

For example, depending on the comparative cost of methane and ammonia, the methane to ammonia molar ratio can range from about 0.6 to about 1.1. In other words, the molar ratio of methane to ammonia can vary beyond what is normally used in the Andrussow process. The methane to ammonia molar ratio can also be in the range of from about 0.62 to about 1.05, or from about 0.65 to about 1.0, or from about 0.67 to about 0.98, or from about 0.7 to about 0.95, or from about 0.75 to about 0.95, or From about 0.65 to about 0.95, or from about 0.7 to about 0.93, or from about 0.75 to about 0.93, or from about 0.75 to about 0.95, or from about 0.77 to about 0.90 or from about 0.77 to about 0.88. The methane to ammonia molar ratio can be any value between about 0.6 and about 1.1.

In some cases, the methane feed rate can be a set point while the ammonia feed is altered in view of cost estimates. Alternatively, the ammonia feed rate can be set to a value while the methane feed is altered in view of cost estimates. In addition, the feed rates of both methane and ammonia are varied.

The adjustment of the composition of the reactants fed to the Andrussow reactor can be limited by suboptimal operating conditions. Exceeding certain ranges of oxygen, methane and ammonia, the HCN yield can be drastically reduced and produce a large amount of waste of valuable reactants. For example, the reaction mixture can be limited by the demand for sufficient oxygen, but it is not possible to have oxygen to flashback and explosion. For example, the normal volume of oxygen in the oxygen Andrussow reaction vessel: volume percent is from about 27% vol/vol to about 31% vol/vol; or from about 28% vol/vol to about 30% vol/vol. When the oxygen system is present in an amount greater than 31% vol/vol, the possibility of flashback in the reaction vessel becomes more likely. At concentrations greater than about 40% vol/vol oxygen, the reaction mixture can be exploded under conditions used for the Andrussow reaction. Thus, the cost saving method described herein does not involve varying the percentage of oxygen in the Andrussow reaction beyond about 31% vol/vol. For oxygen-enriched air or the Andrussow process Andrussow process, a combination of a reaction vessel of the feed may range from about 15-40 vol% CH _4, about 15-45 vol% NH ₄ and about 15-70 vol% of air or Enriched with oxygen air.

The amount of ammonia as a reactant in the Andrussow process becomes higher relative to the amount of methane A larger amount of ammonia may not react. Even during normal operation of the Andrussow process, some unreacted ammonia is typically present in the product stream exiting the Andrussow reactor. For example, unreacted ammonia can be in the range of HCN produced during normal operation of 0.25-0.45 mole ammonia/mole. A moderate amount of ammonia can act primarily as a diluent and pass through the unconverted reaction system.

In addition, ammonia present in the product stream exiting the reactor can be recovered and recycled back to the Andrussow reaction. However, there is a limit to the ability of equipment to recover ammonia. If too much ammonia is present in the product stream exiting the reactor, the ammonia recycle system can be crushed by ammonia. In addition, the Andrussow reaction can be carried out inefficiently in the presence of excess ammonia to produce sub-optimal amounts of HCN.

Therefore, there are several cost factors to be considered when using an increase in the amount of ammonia relative to methane.

First, there are costs associated with ammonia recovery, including energy costs and the cost of supplementing and recycling ammonia absorbent and ammonia stripper materials. Typical costs of recovering unreacted ammonia from the reaction product stream in an ammonia recycle system exist during standard operating conditions. These costs are referred to herein as standard ammonia recovery costs. However, when the product stream from the Andrussow reaction vessel has an increased amount of ammonia, there may be additional energy, processing, and material replenishment costs associated with the ammonia recovery system. These additional costs are referred to herein as "additional ammonia recovery costs."

Secondly, if the ammonia recycle system is crushed by ammonia and ammonia is lost as waste, there is a cost of ammonia loss. These costs are called "ammonia loss costs."

Secondly, there is a cost associated with reducing HCN manufacturing when the amount of methane is significantly limited relative to the amount of ammonia and less than an optimum amount of HCN is produced. These costs are referred to as "the cost of sub-optimal HCN manufacturing related to excess ammonia."

In general, the amount of ammonia in the ammonia can be increased (relative to methane) as long as the savings associated with the use of higher amounts of ammonia are greater than the cost of at least the three factors. For example, the methane to ammonia molar ratio can be reduced (and therefore more ammonia is present than methane) as long as: ammonia price savings > additional ammonia recovery cost + ammonia loss cost + excess ammonia related sub-optimal HCN manufacturing costs.

Unreacted methane in the exhaust from the Andrussow reactor during normal operation The content is estimated to be less than about 2%. Although the common goal of the Andrussow process is to convert 100% methane into a product, the Andrussow reaction can be more abundant than ammonia when the ammonia price is higher (ie, the methane price/unit is significantly lower than the ammonia price/unit). Methane. Thus, the Andrussow process can be implemented to convert not all methane to HCN product. For example, the methane to ammonia molar ratio can be any value between about 0.8 and about 1.1 when the ammonia price is higher and the methane price (/unit) is significantly lower than the ammonia price (/unit).

However, when the amount of methane in the Andrussow process becomes higher relative to the amount of ammonia, by-products and impurities can be formed. High levels of methane produce impurities and by-products such as organic nitriles (eg, acetonitrile, acrylonitrile, and/or propionitrile). High levels of methane can also lead to carbon build-up in the Andrussow reactor and related equipment. For example, carbon formation (coking) can damage the platinum mesh catalyst. The nitrile yield is lost and causes operational problems in ammonia and HCN recovery units. Therefore, increasing the methane content in the reaction vessel significantly exceeds the conversion of most of the methane to HCN to increase the cost associated with impurity formation and ammonia and HCN recovery. The presence of such by-products and impurities can result in increased costs associated with carbon build-up in the Andrussow system, HCN polymerization, reduced HCN recovery, and the like. These costs are called "impurity costs." In addition, a large amount of methane can not react and can be lost as waste. Although excess methane can be recovered from waste streams, many Andrussow reaction systems do not have a methane recovery system. Excess methane is often delivered to the flare. The cost associated with the loss of methane is referred to herein as the "methane loss cost." The imbalance of methane relative to ammonia can also affect HCN manufacturing to produce sub-optimal amounts of HCN over time. These costs are referred to as "the cost of sub-optimal HCN manufacturing associated with excess methane."

In general, the amount of methane can be increased (relative to ammonia) as long as the savings associated with the use of higher amounts of methane are greater than the cost of impurities and lost methane. For example, the methane to ammonia molar ratio can be increased (and therefore more methane is present than ammonia) as long as: methane price savings > impurity cost + methane loss cost + sub-optimal HCN manufacturing costs associated with excess methane.

Monitoring Andrussow reaction

The efficiency of the Andrussow process can vary with the molar ratio of the reactant gases fed to the reactor. Despite some variations in the tolerant reactant ratio, the reactant molar ratio becomes unacceptable when process efficiency is significantly reduced. Adjustment towards a more optimal range improves the efficiency of the reaction and increases the HCN output. This section describes the acceptable range for detecting when the Andrussow reaction is performed in an acceptable manner and how to detect the molar ratio of Andrussow reactants.

The temperature of the Andrussow reaction is a measure of its efficiency. For example, as illustrated in the examples, the temperature can be used as an indicator of the optimum level of methane of the ammonia content in the Andrussow reaction while the ammonia content remains constant. The temperature of the Andrussow reaction is lower for the optimum methane to ammonia ratio, but this temperature increases when the ratio is not optimal and the reaction is less effective. Different methane to ammonia molar ratios operate most efficiently at different temperatures (see Figure 2).

Thus, a procedure for optimizing the manufacture and improvement of HCN involves adjusting the amount of methane or ammonia in the reaction and subsequently changing the amount of the other reactant until the temperature of the Andrussow reaction is close to the minimum temperature of the ammonia and methane content. . This minimum temperature generally means that the reaction burns enough methane to efficiently convert ammonia and methane to a product. However, as the temperature moves away from the optimal minimum temperature, the reactants can also be combusted rather than converted to HCN products.

For example, the value can be optimized after adjusting the ammonia feed ratio into the reactor by adding or adjusting the methane feed until the Andrussow reaction in the reactor is at a minimum reaction temperature to the adjusted methane to ammonia molar ratio. The value is within about 150 ° C, or within about 125 ° C, or within about 120 ° C, or within about 100 ° C, or within about 90 ° C, or within about 80 ° C, or within about 70 ° C, or within about 60 ° C. However, an Andrussow reactor operating at less than about 850 ° C or greater than about 1,500 ° C can operate sub-optimally. In some cases, the Andrussow reaction operates more efficiently at temperatures ranging from about 1000 °C to about 1,300 °C or from about 1050 °C to about 1,250 °C.

Detecting even if the ratio of methane to ammonia is far from the ratio commonly used in the Andrussow reaction, the Andrussow process is also operating at optimum efficiency to monitor HCN output, ammonia loss (also known as ammonia slip). Methane loss (also known as methane leakage) and/or impurities Manufacture of by-products such as organic nitriles.

Gas chromatographic analysis of the product stream exiting the oxygen Andrussow reaction vessel under normal operating conditions has from about 0.01% vol/vol to 20% vol/vol or 15% vol/vol to 20% vol/vol HCN, about 0.1% vol/vol to about 2% vol/vol or about 0.4% vol/vol to 0.8% vol/vol methane and about 0% vol/vol to 6% vol/vol or about 2% vol/vol to about 6% Vol/vol ammonia. When the air Andrussow process is employed, the product stream can be about one-third or less of the components compared to the oxygen Andrussow process. Thus, the product stream exiting the air Andrussow reaction vessel under normal operating conditions has from about 0.01% vol/vol to 7% vol/vol or from about 3% vol/vol to 7% vol/vol HCN, about 0.01% vol. /vol to about 0.25% vol/vol or about 0.075% vol/vol to 0.25% vol/vol methane and about 0% vol/vol to about 2% vol/vol or about 0.4% vol/vol to about 2% vol/ Vol ammonia.

For example, the product stream exiting the Andrussow reaction vessel has less than about 16% vol/vol HCN, or less than about 15% vol/vol HCN, or less than about 14% vol/vol HCN or less than about 13% vol/vol At HCN, the oxygen Andrussow reaction works suboptimally. The air Andrussow reaction may be sub-optimal when the product stream exiting the Andrussow reaction vessel has less than about 4% vol/vol HCN, or less than about 3% vol/vol HCN or less than about 2% vol/vol HCN operating.

In another example, the Andrussow reaction can be operated sub-optimally when the product stream exiting the Andrussow reaction vessel has a generally observed greater than about two percent. For example, the product stream exiting the Andrussow reaction vessel has greater than about 0.8% vol/vol methane, or greater than about 1.0% vol/vol methane, or greater than about 1.5% vol/vol methane, or greater than about 2.0% vol/ The oxygen Andrussow reaction can be operated sub-optimally when vol methane or greater than about 2.5% vol/vol methane. For an air Andrussow reaction, the product stream exiting the Andrussow reaction vessel has greater than about 0.25% vol/vol methane, or greater than about 0.3% vol/vol methane, or greater than about 0.35% vol/vol methane or greater than about When 0.4% methane was used, the next best operation was observed.

In yet another example, the product stream exiting the Andrussow reaction vessel has a generally When the observed ammonia content is about ±10-20% or more, the Andrussow reaction can be operated suboptimally. For example, for the oxygen Andrussow process, the product stream has greater than about 7% vol/vol ammonia, or greater than about 8% vol/vol ammonia, or greater than about 9% vol/vol ammonia or greater than about 10% vol/vol ammonia. The next best operation can be detected. In the case of the air Andrussow process, the product stream has greater than about 2% vol/vol ammonia, or greater than about 3% vol/vol ammonia, or greater than about 4% vol/vol ammonia or greater than about 5% vol/vol ammonia. The next best operation can be detected.

One of the more prominent signs of the second best operation is HCN manufacturing. Thus, if the HCN manufacturing is reduced by about 5%-20% at normal values observed in the product stream, the ammonia and methane feed ratios can be adjusted to improve the HCN product output.

Enriched oxygen to air Andrussow method

The use of an oxygen-rich Andrussow process or an oxygen Andrussow process rather than an air Andrussow process has several advantages. Advantageously, a greater proportion of hydrogen can be produced in the effluent stream by using the oxygen-enriched Andrussow process or the oxygen Andrussow process as compared to the air Andrussow process. In addition, in the oxygen-enriched Andrussow process or the oxygen Andrussow process, there are fewer non-reactive materials or impurity materials in the oxygen-containing feed stream, which reduces the heating cost of the desired reagent prior to entering the reactor. Thereby reducing energy waste. The oxygen-rich Andrussow method or the oxygen Andrussow method can be more compact (smaller) than the air Andrussow method for producing equivalent amounts of HCN.

However, the oxygen-rich Andrussow method or the oxygen Andrussow method can have many problems not addressed in the air Andrussow method. Also, as the oxygen concentration of the feed gas increases, the problem tends to increase. For example, reagents in the oxygen-enriched Andrussow process or the oxygen Andrussow process are diluted less by other gases, such as inert gases. Therefore, the oxygen-rich Andrussow process or the oxygen Andrussow process tends to proceed at a higher concentration than the air Andrussow process. Thus, the oxygen-rich Andrussow process or the oxygen Andrussow process tends to produce higher concentrations of all products, including by-products. Therefore, the reactors and related equipment for the enriched oxygen-based Andrussow process or the oxygen Andrussow process are more likely to accumulate impurities in the system, and the impurities can be It is easier to rinse off the equipment used in the air Andrussow method. Larger byproduct accumulation rates can result in increased corrosion rates and more frequent shutdown and maintenance of portions of the process. Equipment that can be significantly affected by by-product accumulation, corrosion, and related problems include, for example, reactors, ammonia recovery systems, and HCN recovery systems. Due to the higher concentration of reagents in the oxygen-enriched Andrussow process or the oxygen Andrussow process, the sensitivity of the reaction to changes in reagent concentration can be higher than the air Andrussow process. Compared to the air Andrussow process, local variations in reagent concentration as the reagent passes through the catalyst can cause temperature fluctuations in the catalyst bed, such as hot spots, which can shorten catalyst life. The oxygen-rich Andrussow process or the oxygen Andrussow process may require additional safety controls to control the gas mixture with high oxygen content and avoid ignition or explosion. In addition, the heat transfer from the enrichment of the oxygen-rich Andrussow process or the oxygen Andrussow process can be more difficult than in the air Andrussow process, in part due to the higher concentration of effluent than for air Andrussow The method is observed, and cooling the concentrated effluent to the condensing point increases the likelihood of by-product formation, which may not be observed if the effluent is lean. In addition, variations in the concentration or flow rate of the reagents in the oxygen-enriched Andrussow process or the oxygen Andrussow process may result in greater differences in the overall efficiency of the process compared to the air Andrussow process. In the enriched oxygen Andrussow process or the oxygen Andrussow process, the use of the air Andrussow method may not require safe control to avoid combustion or explosion of the gas mixture. Therefore, additional safety schemes in the design and operation of equipment that are not normally used or required in the air Andrussow process are commonly used in the oxygen-enriched Andrussow process or the oxygen Andrussow process. The oxygen-rich Andrussow process or the oxygen Andrussow process is more sensitive to changes in the calorific value of the feed gas; therefore, small changes in the composition of the feed stream can cause temperature fluctuations in the reactor to be greater than for air. Similar to the composition of the feed stream observed in the Rousseau method.

The following examples illustrate some of the effects of changing the methane to ammonia ratio.

Example 1: Changing methane: ammonia molar ratio

The filtered ammonia, natural gas, and air or oxygen are fed to the Andrussow reactor and heated in the presence of a platinum-containing catalyst at a temperature ranging from about 1,050 °C to about 1,200 °C. Pilot scale testing was conducted using a 4 inch inner diameter stainless steel reactor with a ceramic thermal insulation lining. A 40 wt% Pt/10 wt% Rh 40 mesh screen from Johnson Matthey (USA) was loaded as a catalyst bed. The catalyst sheets were supported using perforated alumina tiles. Set the total flow rate to 2532 SCFH (standard cubic per hour). Some reactors are designed to use air as a source of oxygen. Other Andrussow reactors are designed to use oxygen-enriched air oxygen and others are designed to use oxygen as the oxygen-containing feed stream. However, the ratio of ammonia to methane can be varied in any of these methods to reduce cost. Natural gas can also be used in place of pure methane, especially when natural gas has less impurities and consists essentially of methane.

The reactor off-gas containing HCN and unreacted ammonia was quenched in a waste heat boiler to about 350 °C. The cooled reactor off-gas is passed through an ammonia absorption unit containing an ammonium phosphate solution to remove unreacted ammonia. The product off-gas is passed from the ammonia absorber through an HCN absorber where cold water is added to draw in the HCN. The HCN-water mixture is then passed to a cyanide stripper where excess waste is removed from the liquid. The HCN-water mixture is optionally conveyed through a fractionator to concentrate the HCN, after which the product is stored in a tank or used directly as a feedstock.

Several factors and relationships are defined below and are used to assess reactor operation and yield effects. The ammonia yield (Yn) is the chemical yield of HCN from ammonia, expressed as the percentage of HCN produced per ammonia consumed in the reactor: Yn = 100 * (HCN produced / NH ₃ - recycled in feed) NH ₃ ))

Ammonia recycled (recycle NH ₃₎ HCN generated based not consumed, but rather the amount of absorption and re-captured in the ammonia absorption unit. Thus, the ammonia yield (Yn) is a measure of how ammonia is actually converted to HCN. The unreacted ammonia passed as a waste gas from the system and entering the downstream processing operation is factorized into an ammonia yield (Yn).

The ammonia conversion (Cn) variable does not take into account the unreacted ammonia, but is instead simply defined as the percentage of HCN produced relative to the NH ₃ fed to the reactor.

Cn = 100 * (HCN generated / NH ₃ fed)

Similarly, the methane conversion rate (Cc) is defined as the conversion of CH ₄ as a percentage of HCN. Since CH ₄ in the waste gas was not detected in the methods used in the studies, the yield and conversion of methane were synonymous.

Cc=100 *(HCN generated / CH _{4 for} feed)

In some experiments, natural gas (NG) was used in place of methane, especially when the natural gas system was substantially pure methane.

Figure 1 illustrates the conversion of ammonia to HCN using the Andrussow process of natural gas (NG). As shown in Figure 1, the percent ammonia yield (the amount of HCN produced per amount of ammonia consumed in the reaction) decreases as the ratio of ammonia to air increases. The conversion of reactants to HCN is effective at certain ammonia to natural gas ratios. However, the Andrussow reactor overload ammonia can be inefficient. As also shown, the percent yield of methane (or natural gas, NG) increases with increasing ammonia to air ratio, indicating that more methane is converted to HCN when higher levels of ammonia are present in the reaction mixture.

Other experiments have shown that HCN reaction temperature, yield, conversion, and unreacted ammonia (also known as ammonia slip) vary with ammonia and methane to oxygen ratio. Gas chromatographic analysis of the feed stream exiting the oxygen Andrussow reaction vessel under normal operating conditions indicated that the product stream exiting the reaction vessel had about 17% HCN, 0.5% methane, and 4% ammonia.

The bed temperature of the oxygen Andrussow reactor is typically in the range of 1100 ° C to 1200 ° C. However, the bed temperature varies depending on the amount of ammonia relative to methane. As shown in Figure 2, adjusting the methane to oxygen ratio affects the reaction temperature when the ammonia to oxygen ratio is fixed. Specifically, when the methane to oxygen ratio is adjusted to increase the ammonia conversion rate, the temperature is lowered and the minimum temperature occurs near the maximum ammonia conversion rate. This point is the result of competitive exothermic combustion reactions and endothermic cracking and synthesis reactions. As the ammonia to oxygen ratio increases and the methane to oxygen ratio is readjusted to maintain maximum ammonia conversion, HCN production increases and the bed temperature decreases. Thus, these results indicate a measure of the efficiency of the temperature of the Andrussow reaction and how much methane can be added to a fixed amount of ammonia (and vice versa) to optimize the HCN manufacturing identity.

Figure 3 illustrates that the percent conversion of ammonia to HCN varies with the ratio of methane to oxygen. The ammonia to oxygen input ratio remains constant.

Example 2: Impurity form in the presence of unused methane

The Andrussow process was carried out as described in Example 1, except that the amount of methane in the reaction vessel was varied. When the amount of methane in the reaction vessel increases beyond the amount of methane consumed substantially, some of the methane remains unreacted and leaves the reaction vessel. The unreacted methane is detected in the product stream and is referred to as "methane leakage" or "methane loss."

Increasing the amount shown in Figure 4, acetonitrile (CH ₃ CN) during forming of the Andrussow reaction with methane leakage amount of impurities (unreacted methane) of. Specifically, Figure 4 graphically illustrates that a large amount of acetonitrile begins to form when unreacted methane is greater than about 0.5 mole % methane per mole of HCN, and an increased amount of acetonitrile continues to form as the amount of unreacted methane increases. .

The amount of unreacted methane in the reaction off-gas from the oxygen Andrussow reactor was estimated to be less than 1% during normal operation. However, methane leakage increases with the methane to oxygen ratio and increases with increasing ammonia to oxygen ratio. Unreacted methane problems are caused by the presence of a large amount of unconverted methane causing side reactions which result in the formation of carbon on the catalyst screen or in the manufacture of nitriles such as acetonitrile, acrylonitrile and propionitrile.

Example 3: Cost of use to change the molar ratio of methane to ammonia

This example illustrates the cost savings of HCN manufacturing after assessing ammonia and methane costs and using this assessment to adjust the methane:ammonia ratio in the Andrussow process.

The oxygen Andrussow process was carried out as described in Example 1, but with a methane:ammonia ratio of about 0.8.

The average total percentage cost of methane in 1 week is X, while the average percentage of total ammonia in the same week is Y. The cost of ammonia and methane is 90% of the total operating cost of manufacturing HCN (X+Y = 90% of total cost).

Since the methane:ammonia ratio is about 0.8, about 20% less methane than ammonia is used in the reaction. Thus, if the cost per mole of methane is about 0.01 per mole of ammonia, then the total methane cost (X) total ammonia cost (Y) is 0.008, and X = 0.008 (Y) or Y = X / 0.008.

The cost per methane of methane is reduced by about 5% in the next week, so that the average percentage total cost of methane costs is now about 0.95 (X). The cost per mole of ammonia is also increased by about 10% in the same week, so that the average total cost of ammonia cost is about 1.1 (Y). Thus, the total cost of ammonia and methane can thus be greater than 90% of the total operating cost of manufacturing HCN and can be significantly more correlated with ammonia cost than methane cost.

The methane:ammonia ratio in the reactor was adjusted to 0.9 to allow more methane and less ammonia to be used than before. This reduces the overall cost of the more expensive ammonia that is typically used in excess, and thereby reduces the cost of HCN manufacturing.

All of the patents and publications referred to or referred to herein are intended to indicate the state of the art to those skilled in the art to which the invention pertains, and each of which is hereby expressly incorporated by reference herein in The text is incorporated herein by reference in its entirety or in its entirety herein. Applicants reserve the right to actually incorporate any and all materials and information from any such cited patents or publications into this specification.

The specific methods, devices, and compositions set forth herein are representative of the preferred embodiments, and are not intended to limit the scope of the invention. Other objects, aspects and embodiments of the invention will be apparent to those skilled in the art in the light of the scope of the invention. It will be readily apparent to those skilled in the art that various modifications and changes may be made to the inventions disclosed herein without departing from the scope of the invention.

The invention as exemplified herein is suitably implemented in the absence of any one or more of the elements or one or more limitations not specifically disclosed herein. The methods and processes exemplified herein are suitably performed in a different order of steps, and the methods and processes are not necessarily limited to the sequence of steps indicated herein or in the scope of the claims.

The singular forms "a", "an", "the" and "the" are meant to include the plural. because Thus, for example, reference to "a reactor" or "a feed stream" includes a plurality of such reactors or feed streams (e.g., a series of reactors or feed streams) and the like. In this document, the term "or" is used to indicate non-exclusiveness, or "A or B" includes "A but not B", "B but not A" and "A and B" unless otherwise indicated.

In no event should the patent be construed as limited to the specific examples or embodiments or methods disclosed herein. In no event shall this patent be construed as being limited by any statement made by any examiner or any other staff member or employee of the Patent and Trademark Office, unless the statement is answered in writing by the applicant. It is explicitly and unconditionally or unreservedly adopted directly.

The use of the terms and expressions are used in the singular and not restrictive, and the use of such terms and expressions is not intended to exclude any equivalents of the features shown or described, or the various modifications thereof. All of the claimed inventions are within the scope of the invention as claimed. Therefore, it is to be understood that the invention may be modified and modified by the subject matter disclosed herein, and It is within the scope of the invention as defined by the accompanying claims and the claims of the invention.

The invention has been described broadly and generically herein. Each of the narrower categories and subgroups belonging to the generic disclosure also form part of the present invention. This includes the above description of the invention, and conditions or negative restrictions remove any subject matter from the generic class, whether or not the material removed is specifically recited herein. In addition, where features or aspects of the invention are set forth in the Markush group, those skilled in the art will recognize that the invention is therefore in accordance with any individual member or member subgroup of the Markush group. To elaborate.

The following statements set forth some of the elements or features of the invention. Since this application is a provisional application, such statements may change when preparing and submitting a non-provisional application. If such changes occur, such changes are not intended to affect the patent application issued from a non-provisional application. The scope of the equivalent of the scope. According to 35 U.S.C. § 111(b), the scope of patent application is not required for the provisional application. Therefore, according to 35 U.S.C. § 112, the statement of the present invention cannot be construed as a scope of patent application.

statement:

A method of increasing the value in a hydrogen cyanide production facility comprising: (a) assessing the cost of methane and ammonia; and (b) adjusting the feed to the reactor for the production of hydrogen cyanide to ammonia The ear ratio, thereby using the adjusted molar ratio of methane to ammonia, and thereby increasing the value in the hydrogen cyanide manufacturing facility.

2. The method of claim 1, wherein the adjusted methane to ammonia molar ratio varies from about 0.6 to about 1.1.

3. The method of claim 1 or 2, wherein the reactor feeds a reaction mixture comprising methane, ammonia and oxygen.

4. The method of any one of statements 1 to 3, wherein the reactor is fed with a reaction mixture comprising methane, ammonia, and oxygen; and wherein the oxygen is substantially air, oxygen-enriched air, substantially pure A feed stream consisting of oxygen or a mixture of air and inert gas.

5. The method of any of statements 1 to 4, wherein the reactor comprises a catalyst comprising platinum.

6. The method of any of statements 1 to 5, wherein increasing the value in the hydrogen cyanide manufacturing facility comprises reducing the unit cost of hydrogen cyanide production in the facility.

7. The method of claim 6, wherein the unit cost of hydrogen cyanide production in the facility is reduced by up to about 10%, or up to about 8%, or up to about 5%, or up to about 4%, or up to about 3%, or Up to about 2% or up to about 1%.

8. The method of any one of statements 1 to 7, wherein increasing the value in the hydrogen cyanide production facility comprises reducing the unit cost of methane.

9. The method of any one of statements 1 to 8, wherein the addition of the hydrogen cyanide manufacturing facility Value includes the unit cost of reducing ammonia.

10. The method of any one of statements 1 to 7, wherein the market cost of methane and ammonia is the cost per unit or the cost per mole.

11. The method of any one of statements 1 to 10, wherein every day, every 2 days, every 3 days, every week, every 2 weeks, every 3 weeks, every month, every 2 months or between 1 day and 60 The market cost of methane and ammonia is assessed at any interval between days.

12. The method of any of statements 1 to 11, wherein the adjusted ratio is maintained until the cost per unit of methane or cost per unit of ammonia changes.

13. The method of any of statements 1 to 12, wherein the methane to ammonia molar ratio is adjusted when the average cyanide cost during the selection period of the ammonia cost relative to the operation of the hydrogen cyanide manufacturing facility is increased.

14. The method of any one of statements 1 to 13, wherein the methane to the ammonia in the reactor is reduced when the average ammonia cost during the selection period of the ammonia cost relative to the operation of the hydrogen cyanide production facility is reduced The ratio is in the range of from about 0.6 to about 0.95, or from about 0.6 to about 0.9, or from about 0.6 to about 0.85, or from about 0.6 to about 0.8, or from about 0.65 to about 0.95, or from about 0.65 to about 0.9, or about 0.7 to about 0.95, or from about 0.7 to about 0.9 or from about 0.7 to about 0.85.

15. The method of any one of statements 1 to 14, wherein the methane to ammonia molar ratio is in the range below when the average ammonia cost during the selection period of the ammonia cost relative to the operation of the hydrogen cyanide manufacturing facility is increased Internal: from about 0.75 to about 1.1, or from about 0.77 to about 1.1, or from about 0.79 to about 1.1, or from about 0.8 to about 1.1, or from about 0.75 to about 1.05, or from about 0.75 to about 1.0, or from about 0.75 to about 0.98, Or from about 0.75 to about 0.96, or from about 0.75 to about 0.95, or from about 0.78 to about 0.94 or from about 0.78 to about 0.93.

16. The method of any of statements 1 to 15, wherein the adjusted ratio is employed as long as the ammonia price savings is greater than: additional ammonia recovery cost + ammonia loss cost + sub-optimal HCN manufacturing cost associated with excess ammonia.

17. The method of any one of statements 1 to 16, wherein the cost of methane is relative to the cyanide The methane to ammonia molar ratio is adjusted as the average methane cost during the selected period of operation of the hydrogen production facility increases.

18. The method of any one of statements 1 to 17, wherein the adjusted ratio in the reactor is between when the average methane cost during the selection period of the methane cost relative to the operation of the hydrogen cyanide production facility is reduced Within the following ranges: from about 0.75 to about 1.1, or from about 0.77 to about 1.1, or from about 0.79 to about 1.1, or from about 0.8 to about 1.1, or from about 0.75 to about 1.05, or from about 0.75 to about 1.0, or from about 0.75 to about 0.98, or from about 0.75 to about 0.96, or from about 0.75 to about 0.95, or from about 0.78 to about 0.94 or from about 0.78 to about 0.93.

19. The method of any of statements 1 to 18, wherein the adjusted methane cost increases during a selection period of the methane cost relative to the operation of the hydrogen cyanide production facility, the adjusted ratio being within the following range: 0.6 to about 0.95, or about 0.6 to about 0.9, or about 0.6 to about 0.85, or about 0.6 to about 0.8, or about 0.65 to about 0.95, or about 0.65 to about 0.9, or about 0.7 to about 0.95, or about 0.7 To about 0.9 or about 0.7 to about 0.85.

20. The method of any of statements 1 to 19, wherein the adjusted ratio is employed as long as the methane price savings is greater than the impurity cost + methane loss cost + the cost of the sub-optimal HCN manufacturing associated with the excess methane.

21. The method of any of statements 1 to 20, wherein after assessing the market cost of methane and ammonia, the ammonia fed to the reactor is kept constant at approximately the set point and the feed is changed to the reactor Methane in the middle.

The method of any one of claims 1 to 21, wherein after assessing the market cost of methane and ammonia, the methane fed to the reactor is kept constant at approximately the set value and the feed is changed to the reactor. Ammonia in the middle.

23. The method of any of statements 1 to 22, wherein the adjusted molar ratio is employed as long as the temperature of the reactor is in the range of from about 1,000 ° C to about 1,300 ° C, or from about 1,050 ° C to about 1,200 ° C.

24. The method of any one of statements 1 to 23, wherein the adjusted ratio is used, only The temperature of the reactor is within about 150 ° C, or about 130 ° C, or about 120 ° C, or about 100 ° C, or about 90 ° C, or a minimum of the reaction temperature of the selected methane to ammonia molar ratio, or Within about 80 ° C, or about 70 ° C, or about 60 ° C, or about 50 ° C, or about 40 ° C, or about 30 ° C or about 20 ° C.

The method of any of statements 1 to 24, wherein the adjusted ratio is employed as long as the product stream withdrawn from the reactor has at least about 13.5% vol/vol HCN, or at least about 14% vol/vol HCN, Or at least about 14.3% vol/vol HCN, or at least about 14.5% vol/vol HCN, or at least about 14.8% vol/vol HCN or at least about 15% vol/vol HCN.

26. The method of any of statements 1 to 25, wherein the adjusted ratio is employed as long as the product stream exiting the reactor has less than about 3.5% vol/vol methane, or less than about 3.0% vol/vol methane, Or less than about 2.5% vol/vol methane, or less than about 2.0% vol/vol methane, or less than about 1.8% vol/vol methane or less than about 1.5% vol/vol methane.

27. The method of any one of statements 1 to 26, wherein the selected methane to ammonia molar ratio is employed as long as the product stream exiting the reactor has less than about 10% vol/vol ammonia, or less than about 9% vol /vol ammonia, or less than about 8% vol/vol ammonia or less than about 7% vol/vol ammonia.

28. The method of any of statements 1 to 27, wherein the adjusted ratio is readjusted after assessing the market cost of methane and ammonia.

The method of any one of statements 1 to 28, wherein the reactor comprises a catalyst comprising a platinum-rhodium alloy.

The method of any one of claims 1 to 29, wherein the reactor comprises a catalyst comprising from about 85 wt% to about 90 wt% Pt and from about 10 wt% to about 15 wt% Rh.

The method of any one of claims 1 to 30, wherein the reactor comprises a catalyst in the form of a wire mesh, screen or knitted mesh sheet.

32. The method of any one of statements 1 to 31, wherein the cost of methane comprises a market price of methane and an acquisition cost of obtaining methane.

33. The method of any one of statements 1 to 31, wherein the cost of ammonia comprises a market price of ammonia and an acquisition cost of obtaining ammonia.

Claims (21)

A method of increasing the value in a hydrogen cyanide production facility comprising: (a) assessing the cost of methane and ammonia; and (b) adjusting the molar ratio of methane to ammonia used to produce hydrogen cyanide in the reactor. In order to thereby adjust the molar ratio of methane to ammonia, and thereby increase the value in the hydrogen cyanide manufacturing facility. The method of claim 1, wherein the adjusted methane to ammonia molar ratio varies from about 0.6 to about 1.1. The method of claim 1 or 2, wherein increasing the value in the hydrogen cyanide manufacturing facility comprises reducing a unit cost of hydrogen cyanide production in the facility; reducing the unit cost of methane; or reducing the unit cost of ammonia. The method of any one of claims 1 to 3, wherein the costs of methane and ammonia are evaluated daily or weekly. The method of any one of claims 1 to 4, wherein the methane to ammonia is adjusted when the ammonia cost is increased or decreased relative to the average ammonia cost noted during the selection period of operation of the hydrogen cyanide manufacturing facility ratio. The method of any one of clauses 1 to 5, wherein the ammonia feed cost to the reactor is reduced when the average ammonia cost noted during the selection period of operation of the hydrogen cyanide production facility is reduced The methane to ammonia molar ratio A is in the range of from about 0.6 to about 0.9. The method of any one of claims 1 to 6, wherein the feeding to the reactor is increased when the ammonia cost is increased relative to the average ammonia cost noted during the selection period of operation of the hydrogen cyanide manufacturing facility The methane to ammonia molar ratio B is in the range of from about 0.75 to about 1.0. The method of any one of claims 1 to 7, wherein the adjusted ratio is employed as long as Ammonia price savings are greater than: additional ammonia recovery costs + ammonia loss costs + sub-optimal HCN manufacturing costs associated with excess ammonia. The method of any one of claims 1 to 8, wherein the methane to ammonia is adjusted when the methane cost is increased or decreased relative to the average methane cost noted during the selection period of operation of the hydrogen cyanide manufacturing facility. ratio. The method of any one of claims 1 to 9, wherein the adjusted ratio in the reactor is reduced when the methane cost is reduced relative to the average methane cost noted during the selected period of operation of the hydrogen cyanide manufacturing facility The range is from 0.75 to about 1.0. The method of any one of claims 1 to 10, wherein the adjusted ratio is between about 0.6 when the methane cost is increased relative to the average methane cost noted during the selection period of operation of the hydrogen cyanide manufacturing facility. To the range of about 0.9. The method of any one of claims 1 to 11, wherein the adjusted ratio is employed as long as the methane price savings is greater than the impurity cost + methane loss cost + the cost of the sub-optimal HCN manufacturing associated with the excess methane. The method of any one of claims 1 to 12, wherein after assessing the market cost of methane and ammonia, the ammonia fed to the reactor is kept constant at approximately the set value and the feed is changed to the reactor. Methane; or wherein after assessing the market cost of methane and ammonia, the methane fed to the reactor remains constant at approximately the set point and changes the ammonia fed to the reactor. The method of any one of claims 1 to 13, wherein the adjusted molar ratio is employed as long as the temperature of the reactor is in the range of from about 1,000 ° C to about 1,300 ° C, or from about 1,050 ° C to about 1,200 ° C. The method of any one of claims 1 to 14, wherein the adjusted ratio is employed as long as the temperature of the reactor is within about 140 ° C of a minimum reaction temperature of the selected methane to ammonia molar ratio. The method of any one of claims 1 to 15, wherein the adjusted ratio is employed as long as The product stream exiting the reactor has at least about 14.5% vol/vol HCN. The method of any one of claims 1 to 17, wherein the adjusted ratio is employed as long as the product stream withdrawn from the reactor has less than about 2.5% vol/vol of methane. The method of any one of claims 1 to 17, wherein the selected methane to ammonia molar ratio is employed as long as the product stream exiting the reactor has less than about 8% vol/vol ammonia. The method of any one of claims 1 to 18, wherein the adjusted ratio is readjusted after assessing the market cost of methane and ammonia. The method of any one of claims 1 to 19, wherein the reactor comprises a catalyst comprising a platinum-rhodium alloy. The method of any one of claims 1 to 20, wherein the reactor comprises a catalyst comprising from about 85 wt% to about 90 wt% Pt and from about 10 wt% to about 15 wt% Rh.