chapter viii process and economics overview...chapter viii - process and economics overview 358...

CHAPTER VIII

PROCESS AND ECONOMICS

OVERVIEW

Chapter VIII - Process and Economics Overview

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PROCESS AND ECONOMICS OVERVIEW

This portion of the study is intended to provide a general overview of commercially viable methanol, formaldehyde, acetic acid, MMA, MTBE, methylchloride, mixed methylamines, and DME production technologies. For methanol, natural gas and coal based processes are discussed and diagrammed, and general economic models of the natural gas process is provided. For acetic acid, formaldehyde, MMA, and MTBE a simple process diagram is provided, and a general economic model of a methanol carbonylation technology is provided. For mixed methylamines and DME, a brief process description is provided along with an economic model summarizing production costs. For methylchloride, a brief process description is provided. While quite a bit of information is presented on the difference between coal and natural gas based methanol production capabilities in this section, if the reader is looking for a comparative analysis of the outlook for the use of the two feedstocks, they are referred to the “Methanol Supply – Feedstock Dynamics” section of the study. These descriptions are meant for reference and are meant to be utilized mainly for discussion. Application of these towards a particular model or design should be done only after consultation with MMSA staff. MMSA is available to provide more detailed economics and forecasts of the costs of these processes, including detailed capital and replacement cost estimates (among other valuation methods), under separate arrangement.


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METHANOL

Methanol is made from synthesis gas (syngas), which itself is the product of hydrocarbon-rich material that has been heated in the presence of metal catalysts. Almost exclusively, that hydrocarbon is natural gas (methane). However in China, a large amount of production capacity uses coal as the source of hydrocarbons. Therefore, a discussion of natural gas based and coal based methanol production processes is merited. The diagrams in this section are for reference only, and the reader is cautioned that they are not applicable for design of production processes. Natural Gas Based Methanol Production Methanol production from syngas takes place in three major steps: reforming, the catalyzed production of syngas from saturated, de-sulphurized natural gas (reformation); second, methanol synthesis with a Cu/Zn/Alumina catalyst, and finally, crude methanol (water containing) purification via distillation. There are four major established process licensors of methanol process technology. There are relatively minor differences between these technologies, most of these being optimization of the reforming thermodynamics and kinetics. Changes are focused on enabling larger and larger processes, and today’s largest plants (currently under construction) will allow the manufacture of 5,000 tons per day of methanol (1.75 million tons per year). Methanol synthesis and crude methanol distillation technologies are similar (there are 2 and three stage distillation processes) between suppliers, although catalyst technology in the methanol synthesis step varies. Again, most of the differences in methanol production technology can be found in the reforming portion of the process, the most complex of the sections, and where the bulk of cost resides. For natural gas feed, there are two broad commercial reformer designs used today; the first is the original, “conventional” low pressure reformer, which uses natural gas, water, and air as intake, with the other the combined reforming process, which usually incorporates an air separation unit to isolate oxygen sent to a secondary reactor (autothermal oxidation). A major advantage of the combined process is its efficiency in generating “methanol grade” syngas. A third technology, basically an optimized ATR process, which is still being commercialized, offers a more compact reforming section by using heat from the secondary reactor to warm incoming feedstock (rather than imported fuel), further improving efficiency. The low pressure process has been the workhorse of methanol production. However, most new world scale facilities are employing the combined reforming process, and several “mega” facilities are considering the use of the optimized ATR process. Major technology providers include Davy Process Technology (a division of catalyst manufacturer Johnson Matthey), Lurgi, Haldor Topsoe, and Mitsubishi Gas Chemical. These technology suppliers have licensed contractors, who are mostly engineering and construction companies, and currently include Mitsubishi Heavy


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Industry, Chiyoda, Jacobs, Linde, Krupp, Toyo, Technip, and others (including increasing presence of Chinese EPC firms – even in the USGC). For the purposes of this study, comparisons of individual technology providers will be avoided. More details behind each reforming section are provided below. Conventional Reforming Shown below is a generic process schematic for a conventional low-pressure methanol reforming process. Natural gas feedstock, saturated with steam, is heated, and then passed over catalyst, and the resulting syngas is then cooled in a steam heat exchanger, after which it is sent to the methanol synthesis reactors. The steam is used subsequently in other portions of the process.

Conventional Low Pressure Reforming

Combined Reforming In the combined reforming process, a secondary autothermal reformer (ATR) is added in series with the conventional reformer. The ATR uses oxygen in this secondary reforming to optimize methanol synthesis feedstock stoichiometry, as oxygen helps the combustion of excess hydrogen in the natural gas based syngas. Like the conventional reforming step, gas exiting the ATR is cooled and generates


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HP steam. A depiction of the combined reforming step is shown below.

Combined Reforming Optimized ATR Process The optimized ATR process involves a two-staged combined cycle reformer that uses syngas secondary reformer (autothermal) off gas to heat saturated natural gas feedstock. This eliminates the need for fuel to preheat the feedstock, and also maximizes heat transfer (avoids the use of steam). A diagram is offered below.

Optimized ATR Reforming

This process configuration requires specialized metallurgy, as the extremely hot carbon monoxide issuing from the ATR is corrosive to conventional tubes, but cost


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savings per unit throughput are possible due to the relatively smaller reformer size. Methanol Synthesis For methanol synthesis portion of the process, most commercial methanol plants use gas-phase heterogeneous catalytic reactors. Two main methanol synthesis processes account for the majority of methanol produced; the Lurgi process, which uses a water-cooled, tubular, fixed-bed reactor, and the DPT process, which employs larger fixed-bed reactors with interstage cooling. Copper-zinc oxide alumina catalysts are now the standard for methanol plants, but they are subject to sulfur poisoning if sulfur species in the feed gas are not removed to less than 1 ppm. Crude Methanol Distillation Crude methanol (which comes from the synthesis section) contains water and other impurities that must be removed to meet commercial specifications. The amount of distillation is dependent upon the type and quantity of by-product formation from the methanol synthesis catalyst employed. The quantity of by-products typically increases with catalyst age, with ethanol typically being the most troublesome impurity. The first column is a topping column, which removes light ends in the crude methanol. Most processes then use one or two more columns (two and three column finishing) to refine the product to specification grade methanol. The two column system uses an atmospheric refining column to separate out remaining gases and heavier components (including organic contaminated water, which is then treated). A three column system places a pressurized column after the topping column, reducing the amount of heat required for distillation, and can provide relative cost savings when energy prices are high. Coal Based Methanol Production Coal is another significant commercial feedstock for methanol production, and its use is concentrated in coal-rich China. [Please refer to Chapter VI, “Methanol Feedstock Dynamics,” for more discussion about coal use and types in China.] Coal comes in thousands of varieties around the world, varying significantly in chemical composition and energy content. There are coal types which are almost purely hydrocarbon at one extreme (high energy content per ton), and coal types which have high ash and high sulphur content at the other (low energy content per ton). Often, coal is separated into grades according to energy, ash, and sulphur content. Coal is mostly used in heating, but can also be used in the manufacture of steel (coking coal). The production of syngas from coal, which has been a commercial reality since the 1920’s, can be considered in two major subsets in China. The first is where residual gases from the steel production process, which contain large amounts of hydrogen, carbon monoxide, and natural gas (among other components) are reformed to synthesis gas, and then converted to methanol via conventional means. These facilities tend to be limited in sizes not larger than 350,000 metric tons per year, and are driven by investments in steel manufacturing. These “coke oven


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gas” based methanol facilities can be considered as highly competitive when their associated steel making operations are up, as they essentially receive feedstock “free.” Coke-oven methanol is mostly limited to steel mills in China, where it is thought that Chinese towns historically had little other use for the waste gas streams. The second subset of coal based syngas production, and the focus of this section, is coal gasification. This process also follows the three main steps of the natural gas process (reforming, synthesis, and distillation), and are described in greater detail below. Reforming Coal-based syngas processes are significantly more complex than natural gas based systems, and yield a slightly different type of syngas, as the carbon to hydrogen ratio of coal is higher than that of natural gas (therefore coal based syngas has excess carbon dioxide). Without elaboration, the following steps are required in most coal based syngas operations, which are clearly more involved, as they may include feedstock preparation, solids handling (sulphur, slag fines, and ash), and carbon dioxide removal, steps not needed in the natural gas operations: Steps in Coal-based Synthesis Gas Production

Feed Preparation Milling. Drying, Pressurizing and/or Slurrification Air Separation (O2) Gasification Syngas Prep Cooling Desulphurization (COS Hydrolysis) CO2 Removal Converter/Pressurization Sulphur Recovery Water Treatment To Conventional Methanol Synthesis

In making methanol from coal, there are 9 different suppliers of commercial technology for coal gasification, with 4 more under development (one of the commercial suppliers is the Institute of Clean Coal Technology, which has “borrowed heavily” from a leading technology provider, offering a slight modification at more than half of the licensing fee). The main differences technologies differ in the form of the feedstock utilized (dry coal or water slurry), and the type of gasifier reactor (entrained bed, fluid bed, moving bed). MMSA has more information on the various types of gasification, available on request.


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The following schematic shows a “generic” commercial coal gasification process, which highlights the differences between coal and natural gas reformers.

The largest proven single line units process 2500 tpd coal (approx 600,000 methanol at 100 percent availability), with larger scale envisioned. This process is also used as the “front end” of other processes, including IGCC (combined cycle), ammonia production (in China), among others. Methanol Synthesis and Distillation The process diagram for methanol production is very similar to that of the natural gas based systems. However, syngas from the coal based process must be heated and pressurized before being sent to the synthesis unit, as coal based syngas contains sulphur and excess carbon dioxide (lower carbon to hydrogen ratio in the feed), and must be treated before synthesis. Distillation technology is not significantly different compared to natural gas systems. On the following page, an overall conventional methanol process schematic for natural gas is provided. The coal process schematic, which is not included, would mostly differ only in the reforming end.


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Reformer Reactor Refining

Low Pressure

Combined (ATR)

“Optimized” ATR

Remove Condensate

Compress Syngas

Contact with Catalyst

Two or Three Column

Separate out water, gases, fusel oil

Natural Gas (Desulphurized)

Steam

MeOH

Simplified Methanol Flow Diagram

Process Steam

HeatRecovery

Fuel Water


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Methanol Process Capital and Operating Costs Natural Gas Based Production In the table below, costs to manufacture and deliver methanol from a “typical” Middle East Gulf supplier to a coastal China location are provided, using representative pricing placeholders (as with all of these “snapshots,” they are easily updated – please contact MMSA). There is a comparison between conventional low pressure and combined reformer economics, which show a slight operational cost advantage. However, it should be noted that the capital costs of the combined reformer are slightly higher, owing to additional equipment required to separate oxygen for the secondary (ATR) reformer in that process.

Low Pressure Combined Reformer Low Pressure Combined Reformer

Variable Costs

Feedstock MMBtu/t 32.0 28.0

Net Fuel (incl O2 for CR) MMBtu/t 3.0 5.5

Total MMBtu/t 35.0 33.5 43.8 41.9

Electricity kWh/t 70 70 4.2 4.2

Cooling Water Makeup m3/t 8.05 8.05 0.5 0.5

Boiler Feedwater Makeup m3/t 0.75 0.75 0.1 0.1

Catalyst per ton 1.75 1.75 1.8 1.8

Total Variable 50.2 48.4

Fixed Costs

Labor per ton 4 4 4.0 4.0

Others (SGA, IOWC, Maint.) per ton 12 12 12.0 12.0

Frieght to Market per ton 40 40 40.0 40.0

Total Fixed 56.0 56.0

Total Delivered Cost (China) 106.2 104.4

Assumptions

Natural Gas Price 1.25 USD/MMBtu

Electricity Cost 0.06 USD/kWh

Cooling Water 0.06 USD/m3

Boiler Water 0.07 USD/m3

Freight PG - China 40.00

Costs, US $ per metric tonUnit Production Requirements

Methanol Production Costs900,000 tpy unit, 100 percent utilization, MeOH Middle East Delivered China

Capital costs for today’s world scale natural gas based methanol facilities (between 1.6 and 1.9 million metric tons per year) vary significantly depending upon location, existing infrastructure, civil works required for site preparation, and numerous other variables. The range of costs for such facilities has skyrocketed in recent years, owning mostly to labor and raw material price escalation. The range of costs for a new facility (world scale, greenfield) in the recent years could vary between 550 and 900 USD per metric ton of installed capacity, accordingly. For more information on specific costs, please contact MMSA.


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Coal Based Production Given the large amount of materials needed (especially large scale refractory and the associated structural support required), plus more complex process and handling equipment on the reforming side versus natural gas based production, much larger capital investment is required for a coal based reformer than for a natural gas reformer. The costs are quoted in a range estimated to be 2.8 to 3.1 times higher. The largest single trains on coal based plants are limited by reformer size, which allow methanol production facilities no greater than 600,000 metric tons per year. Like natural gas based production, costs depend upon location, existing infrastructure, and site preparation costs, among others. In general, coal based synthesis gas requires 1.5 to 2.0 tons of coal per ton of methanol production, with the variation depending on coal type. Water costs can vary significantly, depending on local resource availability and the amount of water recycling designed into the process. Fixed costs of operating facilities are also up to twice as high, with more operations (solids, dust handling as described above), and higher maintenance costs. In the table below, costs to manufacture and deliver methanol from a “typical” Inner Mongolia (China) location are provided, using representative pricing figures.

Unit Production Requirements Costs, US $ per metric ton

Variable Costs

Coal mt/mt 1.60 80.0

Raw Water (net after recycle) m3/mt 0.75 5.2

Catalyst per ton 2.64 2.6

Total Variable 87.9

Fixed Costs

Labor per ton 18.9 18.9

Others (SGA, IOWC, Maint.) per ton 44.0 44.0

Frieght to Market per ton 81.0 81.0

Total Fixed 143.9

Total Delivered Cost 231.7

Assumptions

Coal Price 50.00 USD/mt

Raw Water 7.0 USD/m3

Employees 105 Per Shift

Average Wage 36.0 MUSD/year

Total Fixed Investment 480.00 MMUSD/installed ton capacity

% Other Fixed Cost of TFI 5.5%

Freight 81.00 Rail to Port (Northeast China)

Methanol Production CostCoal-Fed Slurry Gasifier, 600,000 tpy unit, Inner Mongolia Delivered East China

Based on GE Process


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As stated earlier, the amount of coal required per ton of methanol production can vary widely, and the number chosen is at the low end of the range. Additionally, many of the other assumptions used are highly site variable (especially water costs, labor cost, and freight to market). Further information can be found in the “Methanol Supply – Feedstock Dynamics” section of this study, or by contacting MMSA.


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FORMALDEHYDE

Most of the world's commercial formaldehyde is manufactured from methanol and air either by a process using a silver catalyst or one using a metal oxide catalyst (Formox process). Essentially all formaldehyde is produced as aqueous solutions containing 25-56 wt % HCHO and 0.5-15 wt % CH3OH. Yields from both processes are around 90% to 92% but the oxidation route has a lower reaction temperature and the metal catalyst is cheaper than silver. While there is still a significant quantity of silver based systems in operation, the vast majority of new facilities incorporate the metal oxide process. Silver Catalyst In the silver catalyst route, vaporized methanol with air and steam is passed over a thin bed of silver-crystal catalyst at about 650°C. Formaldehyde is formed by the dehydrogenation of methanol. The heat required for the endothermic reaction is obtained by burning hydrogen contained in the off-gas produced from the dehydrogenation reaction. Today there are two main routes: oxidation-dehydrogenation using a silver catalyst involving both the complete or incomplete conversion of methanol and the direct oxidation of methanol to formaldehyde using metal oxide catalysts. Metal Oxide Catalyst The other route involves the oxidation of methanol over a catalyst of molybdenum and iron oxide. A mixture of air and methanol is vaporized and passed into catalyst-packed reactor tubes. The reaction which takes place at 350oC is highly exothermic and generates heat to provide steam for turbines and process heating. A simple process flow diagram depicting the DB Western process is provided on the following page:


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VENT

REACTION CATALYTIC

INCINERATIONABSORPTION

WATER

METHANOL

AIR

BOILER FEED WATER

EXPORT STEAM

UREA WATER

E-109

E-108

E-110

E-106

E-107

E-111

E-104

E-105

E-101

E-102

E-103

UFC-85

37-52% HCHO

ME-100

VENT

REACTION CATALYTIC

INCINERATIONABSORPTION

WATER

METHANOL

AIR

BOILER FEED WATER

EXPORT STEAM

UREA WATER

E-109

E-108

E-110

E-106

E-107

E-111

E-104

E-105

E-101

E-102

E-103

UFC-85

37-52% HCHO

ME-100

In this process, note the optional incorporation of urea-water mixtures to the absorption column to yield urea-formaldehye concentrates (UFC). Perstorp offers a high pressure version of the Formox process which can be retrofitted to existing plants to boost capacity. The high conversion rate of the Perstorp process eliminates the need for methanol recovery via distillation and it can produce formaldehyde at concentrations up to 57%. Other Processes A wide range of alternative feedstocks can be used, but are generally not economic. The ancient process of non-catalytic oxidation of propane-butane mixtures is no longer in use. Formaldehyde can be produced from methane but a mixture of products needs to be separated. It is also a byproduct of the oxidation of naphtha to acetic acid. Finally, while no commercial processes using the technology are known, much effort has been spent on making formaldehyde directly from methane by partial oxidation. The incentive for such a process is reduction of raw material costs by avoiding the capital and expense of producing the methanol from methane. Formaldehyde Process Capital and Operating Costs In the table on the next page, costs to manufacture formaldehyde from a hypothetical manufacturing location are provided, using representative pricing figures. Assumptions for feedstock, utilities, catalyst, and fixed costs used are listed. The process assumed is a commercially available Uhde system.


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Udhe Inventa-Fischer Process

Variable Costs

Feedstock - Methanol mt/mt 0.45 129.1

Feedstock - Water mt/mt 0.39 42.9

Electricity kWh/mt 38 2.3

Cooling Water m3/mt 40 2.4


Total Variable 179.1

Fixed Costs




Total Fixed 14.5

Total Cost 193.6

Assumptions

Methanol Price 290.00 USD/mt

Process Water 110.00 USD/mt


Steam @ 100 psig 15.00 USD/mt



Formaldehyde Production Costs150,000 tpy unit, 100 percent utilization, Ex-Works (37 wt% aq. soln.)


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ACETIC ACID

Capital and Operating Costs – Carbonylation Acetic acid technology is perhaps the most diverse of all major industrial organic chemicals. No other large volume chemical can claim the varied feedstocks and production approaches that acetic acid can. However, methanol carbonylation has become the dominant acetic acid production technology, accounting for over 65% of global capacity, with the majority of the balance from acetaldehyde and butane-naphtha oxidation. Acetic acid is also a by-product of xylene oxidation to terephthalic acid, although that process overall requires net addition of acetic acid. Discussion below will focus on the most commercial routes. World-scale acetic acid plant size using methanol carbonylation technology has also grown significantly from less than 50 thousand metric tons per year in the 1960s to as much as 600,000 metric tons per year per line. Methanol Carbonylation Patented processes for adding carbon monoxide to methanol to produce acetic acid go back to the 1920’s, and commercialization efforts were undertaken by BASF in the 1960’s. In 1970, Monsanto commercialized a rhodium carbonyl iodide catalyst that is included in what is commonly called the Monsanto Acetic Acid Process. The process transformed the market because of lower cost raw materials, gentler, lower cost operating conditions, and higher yields. In the early 1980s, Celanese developed a major improvement over the Monsanto technology (AO Plus), also based on rhodium (with lithium iodide/CH3I co-catalyst), that allowed considerably higher throughput and efficiency in the catalysis and reduced side reactions caused in the Monsanto process. In 1986, Monsanto sold its acetic acid plant and technology to BP. Since then, BP has further advanced the technology using a proprietary Cativa™ (iridium with CH3I co-catalyst) catalyst. Each improvement has lowered the unit cost of producing acetic acid. Chiyoda has recently developed its own process (ACETICA), which employs rhodium catalyst and a CH3I immobilized co-catalyst complex. A process schematic for the ACETICA process is provided on the following page. A very closely related process to methanol carbonylation is the Eastman Chemical carbonylation of methyl acetate to produce acetic anhydride (essentially the same as the rhodium based processes, only the initial reactant has changed). Methyl acetate carbonylation yields both anhydride and acetic acid, controllable in part by the conditions. A plant based on this process was put in operation in 1983.


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In this process, methanol is split into two absorbers, and eventually charged to a bubble-column reactor (sparged carbon monoxide provides the bubbles). Reactor product is flashed and dehydrated to remove heavy ends and water/light gases, respectively. The finishing column separates heavy byproducts, and trace iodide components are removed. An incinerator processes unconverted CO, methane, and other light byproducts off the absorbers, as well as heavy ends from the finishing column. Flue gases are scrubbed. Acetaldehyde Oxidation In this process, ethanol is dehydrogenated oxidatively to acetaldehyde using silver, brass, or bronze catalysts. Acetaldehyde can then be oxidized in the liquid phase in the presence of cobalt or manganese salts to yield acetic acid. This route to acetic acid is reliable, but requires higher cost ethanol as well as extra purification steps, and therefore cannot compete on a cost basis with methanol carbonylation (and is becoming less prevalent). Butane-Naphtha Liquid-Phase Catalytic Oxidation Direct liquid-phase oxidation of butane and/or naphtha was once the most favored worldwide route to acetic acid, but the costs of these hydrocarbons has become prohibitive in recent years and the process is increasingly used less. Butane, in the

Bubble

Column

Reactor

Flasher

Rhodium complex catalyst

Methanol

BFW

Acetic Acid

Simplified Acetic Acid Flow Diagram

(Based on Chiyoda’s ACETICA Process)

Cooler

Steam

Absorbers

CO

Dehydration Finishing

Incinerator

Remove

Heavy

Ends for

Recycle

Remove Water,

Light Gases Heavy Ends

CH3I

Makeup

Air,

FuelFlue Gas

Bubble

Column

Reactor

Flasher

Rhodium complex catalyst

Methanol

BFW

Acetic Acid

Simplified Acetic Acid Flow Diagram

(Based on Chiyoda’s ACETICA Process)

Cooler

Steam

Absorbers

CO

Dehydration Finishing

Incinerator

Remove

Heavy

Ends for

Recycle

Remove Water,

Light Gases Heavy Ends

CH3I

Makeup

Air,

FuelFlue Gas


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presence of cobalt, chromium, or manganese, undergoes simple air oxidation in acetic acid solvent. Ethyl acetate and butanone are produced, and the process can be altered to provide larger quantities of these valuable materials. Formic acid, propionic acid, and minor quantities of butyric acid are also formed. Some safety concerns also exist for this process, as two explosions, in 1987, at the then-largest butane liquid-phase oxidation plant resulted in fatalities. Direct Oxidation of Ethane SABIC has developed a new process for producing acetic acid via catalytic gas phase oxidation of ethane. According to SABIC's patents, ethane is oxidized with either pure oxygen (i.e., ethane rich) or air (i.e., ethane lean), at temperatures ranging from 150°C to 450°C and at pressures ranging from 1 to 50 bar, to form acetic acid and water. Undesired by-products of CO, CO2, and ethylene (largely lost on recycle) can also be formed. The new SABIC catalyst system is a calcined mixture of oxides of Mo, V, Nb, and Pd. Little is known about the costs of such a process. Currently, this process is not expected to materialize on any significant commercial scale through the study period. Acetic Acid Process Capital and Operating Costs Methanol Carbonylation Based Production In the table on the next page, costs to manufacture and deliver acetic acid from a hypothetical integrated Southeast Asian manufacturing location are provided, using representative pricing figures, and estimates of feedstock, utilities, catalyst, and fixed costs, with assumptions used listed. Producers can optimize costs by integrating near petrochemical and refining areas that have readily available CO or CO feedstock. Capital costs for today’s world scale methanol carbonylation facilities (between 0.5 and 0.6 million metric tons per year) vary significantly depending upon location, existing infrastructure, civil works required for site preparation, and numerous other variables. While costs of construction are typically not detailed in most project announcements, the range of costs for Greenfield facilities are estimated to vary between 450 and 700 USD per metric ton of installed capacity. For more information on specific costs, please contact MMSA.


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ACETICA Process (Chiyoda Corp.)

Variable Costs


Feedstock - Carbon Monoxide mt/mt 0.52 165.4


Steam mt/mt 1.7 25.5




Fixed Costs




Total Fixed 57.0

Total Delivered Cost (China) 432.1

Assumptions


Carbon Monoxide Price 320.0 USD/mt





Freight SEA - China 27.00

Acetic Acid Production Costs200,000 tpy unit, 100 percent utilization, SEA Delivered China (CFR)

(Based on Chiyoda ACETICA Process)


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MMA

Methyl methacrylate (MMA) has three basic categories of production, all of which use methanol. Most of the world’s supply of MMA is produced by “C3” routes, starting with propylene. These are more commonly known as acetone cyanohydrin (ACH) processes. These have been practiced commercially since 1937, based on technology patented by ICI in 1934. There have been significant improvements in catalysts and resulting yields for key transformations in many routes since the 1980s. ACH is prepared via a base-catalyzed reaction of acetone and hydrogen cyanide. Acetone and hydrogen cyanide are obtained as by-products from the commercial production of phenol and acrylonitrile, respectively. Phenol and acrylonitrile are made from propylene. Mitsubishi Gas Chemical Co. has developed and patented a modified acetone cyanohydrin-based route that does not use sulfuric acid and therefore presents the opportunity for reduced waste costs, but is not commercially used. A rough schematic of the steps involved in the various commercial routes to MMA is provided below:

Simplified MMA Flow Diagram

(Generic Processes)

MTBE or TBA

Proprionaldehyde

“C3 Route” Propylene

Isobutylene Methacrolein

Esterification

meOH

O2

Hydrogen Cyanide

Acetone

(ex phenol)Acetone

Cyanohydrin

Methacrylamide

Sulfate

“C4 Route” Oxidation

MMA

Ethylene

“C2 Route”

- meOH

(Raff-1)

“C4 Route”

Several “C4” processes are commercially viable and growing in commercial significance, particularly in Asia as more C4 streams come available from investments in refinery and heavy feed olefins complexes. In 1982, Japanese researchers introduced an isobutylene-based process, and by 1984 commercial production via isobutylene was underway in Japan. Isobutylene or tert-butyl alcohol (TBA) can be converted to methacrylic acid in a two-stage, gas-phase oxidation process via methacrolein as an intermediate. Depending on technology, the methacrylic acid is either isolated and the remaining methacrolein is fed to the second stage or product gas from the first-stage reactor is directly introduced into the second-stage reactor without isolating methacrolein. TBA and isobutylene may be used interchangeably in the processes since tert-butyl alcohol readily dehydrates


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to yield isobutylene under the reaction conditions in the initial oxidation. MTBE can also be “backcracked” to yield isobutylene and methanol (which can be utilized in the later esterification to MMA). Variations of the C4 process have been commercialized by Mitsubishi Rayon and by what is now Sumitomo. Finally, “C2” MMA processes utilize ethylene as a feedstock via propanol, propionic acid, or methyl propionate as intermediates. Propanal may be prepared by hydroformylation of ethylene over cobalt or rhodium catalysts. The propanal then reacts in the liquid phase with formaldehyde in the presence of a secondary amine and, optionally, a carboxylic acid. BASF began operation of an ethylene-based plant in Ludwigshafen, Germany, in 1990, based on propanal, which is available at that site. However, propanal is typically not available in significant quantities, and favorable economics appear to be limited to conditions unique to that site. Lucite has built an ethylene based facility (using their proprietary “Alpha” technology) in Singapore, which was commissioned in late 2008. MMA Process Capital and Operating Costs Isobutylene (Raffinate-1) Based Production In the table on the next page, costs to manufacture and deliver MMA from a hypothetical integrated Southeast Asian manufacturing location to China are provided, using representative pricing figures, and estimates of feedstock, utilities, catalyst, and fixed costs, with assumptions used listed. Producers can optimize costs by integrating near petrochemical and refining areas that have readily feedstocks and utilities. Capital costs for today’s world scale C4 based (between 80,000 to 100,000 metric tons per year) vary significantly depending upon location, existing infrastructure, civil works required for site preparation, and numerous other variables. While costs of construction are typically not detailed in most project announcements, the range of costs for greenfield facilities are estimated to vary between 1200 and 1600 USD per metric ton of installed capacity. For more information on specific costs, please contact MMSA.


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Combined Reformer

Variable Costs


Feedstock - Raffinate-1 mt/mt 1.56 889.2


Steam @ 5bar mt/mt 7.4 185.0

Oxygen mt/mt 0.48 57.6

Process Water m3/mt 0.22 0.0


Credits

Raffinate-2 mt/mt 0.86 -481.6

Water mt/mt 0.04 0.0

Fuel Oil (net) mmbtu/mt 2.60 -31.2

Total (Net) Variable 835.1

Fixed Costs




Total Fixed 182.0

Total Delivered Cost (China) 1017.1

Assumptions

Methanol Price 300 USD/mt

Raffinate-1 Price 570 USD/mt


Fuel Oil Price 12.00 USD/mmBtu


Steam @ 5bar 25.0 USD/mt

Oxygen 120 USD/mt

Process Water 0.05 USD/m3

Water 0.03 USD/m3

Freight SEA - China 27.00

Methyl Methacrylate Production Costs90,000 tpy Raffinate-1 unit, 100 percent utilization, SEA

Delivered China (CFR)


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MTBE

MTBE is produced using methanol and isobutylene. Isobutylene used in MTBE operations is sourced from three major upstream locations:

• Refinery/Petrochemical plants: Dilute isobutylene (contained in a stream called “raffinate-1”) is produced as a byproduct in refinery catalytic crackers and in olefin crackers, and is reacted with methanol to produce MTBE after a further butadiene recovery step (in most cases). The C4’s from the refinery can also be referred to as “B/Bs (butylenes/butadienes)”, whereas the C4’s from the crackers are often called “Crude C4s.” The olefins based raff-1 stream is usually higher in isobutylene than the refinery based one. A byproduct of these processes is a stream of residual C4 isomers (raffinate-2). These are the smallest and the least expensive MTBE plants to build, and the use of readily available streams generally improves their competitiveness.

• Butane Dehydrogenation (Merchant) plants: These facilities isomerize normal butane to isobutane, dehydrogenate isobutane to isobutylene, and then react the isobutylene with methanol to produce MTBE. Most of these “on-purpose” (as opposed to using byproduct streams) plants were built in North America, South America and the Middle East from the early 1990’s.

• TBA plants: Tertiary butyl alcohol (TBA) is a byproduct of the styrene monomer/propylene oxide (SM/PO) production process. TBA is converted to isobutylene, then reacted with methanol to produce MTBE. Only a few facilities globally use this process.

A simple schematic summary of these various routes is provided in the chart below.

Simplified MTBE Flow Diagram

(Comparing 4 Major iso-C4= Sources)

MTBE

Operations

C4

Recovery

C4 ex Olefins Unit

(“Crude C4s”)

C4 ex Refinery

(“B/Bs”)

Purification,

Recycle

MTBE

H2O

Dehydration

Dehydrogenation

C4 ex Gas Plant

Isobutane

MeOH

TBA ex

PO/SM

Butadiene

IsobutyleneResidual C4

Isomers

(Raff-2)

(Raff-1)

H2


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Technology providers historically include Snamprogetti/ANIC, ARCO, C.W. Huels, Phillips, Texaco, Shell, CDTECH (a JV between CR&L and ABB Lummus Crest), UOP, Davy-McKee, Suntech, Gulf and Erdoelchemie. The CDTECH, Gulf and Erdoelchemie processes cover the production of tertiary amyl methyl ether (TAME) in addition to MTBE. MTBE Process Capital and Operating Costs Refinery/Petrochemical (Raffinate-1) Based MTBE Production In the table below, estimates of costs to manufacture MTBE at a hypothetical integrated China manufacturing location are provided, using representative pricing figures, and estimates of feedstock, utilities, catalyst, and fixed costs. The scale of this facility is 100,000 metric tons per year (2,300-barrel per day), utilizing a standard raffinate-1 based process. Producers can optimize costs (capital and operational) by integrating near petrochemical and refining areas.


Combined Reformer

Variable Costs


Feedstock - Raffinate-1 mt/mt 1.45 942.5

Electricity kWh/mt 14.20 0.9

Steam, LP (5bar) mt/mt 0.72 11.5

Cooling Water m3/mt 40.30 2.4

Fuel mmBtu/mt 0.48 3.4

Catalyst per mt 3.20 3.2

Credits

Raffinate-2 mt/mt 0.82 -524.8


Fixed Costs



Frieght to Market per ton n/a

Total Fixed 26.0

Total Cost (ex-works) 583.5

Assumptions




Natural Gas Price 7.00 USD/mmBtu

Hydrogen Price 3504 USD/mt


Steam, LP (5 bar) 16.00 USD/mt


Methyl tert-Butyl Ether Production Costs100,000 tpy Raffinate-1 unit, 100 percent utilization, China, ex-works Basis


383

Capital costs for this scale of facilities vary significantly d epending upon location, existing infrastructure, civil works required for site preparation, and numerous other variables. While costs of construction are typically not detailed in most project announcements, the range of costs for Greenfield facilities of this size are estimated to vary between 250 and 300 USD per metric ton of installed capacity. For more information on specific costs, please contact MMSA n-Butane Based MTBE Production The table on the next page summarizes estimates of costs to manufacture MTBE at a hypothetical Middle East n-Butane based manufacturing operation, using representative price figures, and estimates of feedstock, utilities, catalyst, and fixed costs, with assumptions used listed. The scale of this facility is 650,000 metric tons per year (approx 15,000-barrel per day). As with the previous example, producers can optimize costs (capital and operational) by integrating near petrochemical and refining areas.


384


Combined Reformer

Variable Costs


Feedstock - Butane mt/mt 0.69 340.1

Feedstock - Hydrogen mt/mt 0.01 5.0

Electricity kWh/mt 47.50 2.4

Steam, LP (5bar) mt/mt 1.31 15.7

Cooling Water m3/mt 42.70 2.1

Fuel mmBtu/mt 0.48 0.6

Catalyst per mt 43.70 43.7

Credits

Hydrogen mt/mt 0.02 -13.8

Fuel mt/mt 0.04 -20.5


Fixed Costs




Total Fixed 69.8

Total Delivered Cost (Singapore) 557.9

Assumptions


Butane Price 490 USD/mt

Natural Gas Price 1.25 USD/mmBtu

Hydrogen Price 626 USD/mt


Steam, LP (5 bar) 12.00 USD/mt


Freight ME Gulf - Singapore 32.00 USD/mt

Methyl tert-Butyl Ether Production Costs650,000 tpy n-Butane Dehydro unit, 100 percent utilization, Middle East, CFR

Singapore Basis

Capital costs for this scale of facilities vary significantly depending upon location, existing infrastructure, civil works required for site preparation, and numerous other variables. While costs of construction are typically not detailed in most project announcements, the range of costs for greenfield facilities of this size are estimated to vary between 450 and 525 USD per metric ton of installed capacity. For more information on specific costs, please contact MMSA.


385

METHYL CHLORIDE

Making methyl chloride is the first step in the manufacture of chloromethanes. Methyl chloride is the product of a substitution reaction between hydrogen chloride and methanol. In this process, different levels of chlorine addition to the carbon molecule are achieved, resulting in methyl chloride, methylene chloride, chloroform, and carbon tetrachloride. Chlorine can be mixed with excess methyl chloride to increase the yields of the three other chloromethanes. Products are separated after reaction. This reaction is usually carried out in the gas phase thermally but can also be done catalytically or photolytically.


387

MIXED METHYLAMINES

Commercial production of mixed methylamines requires ammonia and methanol. These are reacted in the presence of a catalyst, along with recycled amines. The reaction is exothermic and heat is recovered in feed preheating. Reactor products are sent to a separation system where the ammonia is taken out and recycled. Further processing removes the various amine types. Methanol recovery is possible. Mixed Methylamine Process Capital and Operating Costs Recent manufacturing costs for mixed methylamines are estimated on the next page. Assumptions for feedstock, utilities, catalyst, and fixed costs are listed. Equal parts of mono, di, and tri methylamines are manufactured in this model. In practice, a larger percentage of dimethylamine is manufactured. The process assumed is a commercially proven Davy Process Technology system.


388


DPT Process 3 x 1/3 mono, di, tri

Variable Costs


Feedstock - Ammonia mt/mt 0.40 140.0






Fixed Costs




Total Fixed 226.6

Total Delivered Cost 944.4

Assumptions


Ammonia Price 350.00 USD/mt







Total Fixed Investment 140.00 MMUSD


Freight 0.00

Mixed Methylamines Production Cost Estimates40,000 tpy unit, 100 percent utilization, FOB USGC

Based on Davy Process Technology (Leonard) Process


389

DIMETHYL ETHER (DME)

Commercially, most DME is made via the methanol dehydration route, where crude (containing water) or refined methanol is reacted in the presence of a catalyst. Reactor effluents – DME with byproduct water and unconverted methanol – are fed to a DME separation column. DME is cooled and stored. Methanol is recovered and recycled with feedstock. DME Process Capital and Operating Costs In the table below, costs to manufacture DME from a hypothetical manufacturing location are provided, using representative price figures. Assumptions for feedstock, utilities, catalyst, and fixed costs are listed. The process assumed is a commercially proven system.


DPT Process

Variable Costs





(0.35MPa, 32℃)

Catalyst kg/mt 0.80 4.0


Fixed Costs




Total Fixed 29.8

Total Cost 508.7

Assumptions






Catalyst Cost 5.00 USD/kg



Total Fixed Investment 17.50 MMUSD


Freight 0.00

Dimethyl Ether Production Cost Estimates50,000 tpy unit, 100 percent utilization, FOB China

Methanol Dehydration Process

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