PERP/PERP ABSTRACTS 2009
Vinyl Chloride Monomer (VCM)/
Ethylene Dichloride (EDC)
Ethylene- and Acetylene-Based VCM
Process Technology, Cost of
Producing VCM via Balanced
Oxychlorination, Bioethylene, &
Acetylene Routes. Cost of Producing
EDC by Vinnolitt’s Vin-Tec Boiling
Reactor Process, & by Direction
Chlorination Route. Safety, Health &
Environmental Issues. Regional
Supply/Demand.
PERP 08/09-4
Report Abstract
October 2009
Vinyl Chloride Monomer (VCM)/
Ethylene Dichloride (EDC)
PERP 08/09-4
Report Abstract
October 2009
www.chemsystems.com
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Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC)
INTRODUCTION
Historically, vinyl chloride monomer (VCM, chloroethene, chloroethylene) was not produced
from ethylene dichloride (EDC), but by the reaction of acetylene with hydrogen chloride (HCl)
in the presence of a mercuric chloride catalyst. Until the early 1950s, this acetylene-based
technology predominated. The industry has spent several decades moving away from this
technology due to the energy input necessary to produce acetylene and the hazards of handling it.
Thereafter, ethylene-based routes have since become predominant. In addition, there seem to be
no environmental or economic incentives to reverse this trend (i.e., there is a strong
environmental incentive to cease the use of the mercury-based catalyst involved in the acetylene-
based process). Today, this process is largely obsolete outside China, where the availability of
relatively cheap local coal makes it economically attractive to continue with this technology.
These historical economic drivers are unlikely to continue long-term, but there is still interest in
this technology where supplies of oil are scarce or potentially scarce.
Currently, commercial VCM capacity can be categorized based on the feedstocks acetylene and
ethylene. The Figure below shows the VCM capacity share of these two feedstocks. Ethylene is
the dominant feed source for the production of VCM outside of China.
Global VCM Capacity by Feedstocks
Acetylene
18%
Ethylene
82%
Total Capacity = 42.7 Million Tons
Q309_00101.0009.4104_Charts.xls\ F 2.1
With the incentives of lower cost feedstock and simpler process scheme, the development of
ethane-based technology for the production of VCM has been a long identified, albeit difficult to
realize, target of VCM process research. A number of companies have been involved in the
attempted development of an ethane-based process, several processes have been patented, but as
yet none have been commercialized.
CHEMSYSTEMS PERP PROGRAM 1
Report Abstract – Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC) 08/09-4
www.chemsystems.com
PERP ABSTRACTS 2009 00101.0009.4104
Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC)
CONVENTIONAL TECHNOLOGY
Acetylene-Based VCM
The classical commercial route to acetylene is the calcium carbide route in which lime is reduced
by carbon (in the form of coke) in an electric furnace to yield calcium carbide:
The calcium carbide is then hydrolyzed to produce acetylene:
There are two principal methods for producing acetylene from calcium carbide, based on the
type of generator used. In the wet generator, the reaction takes place in a cylindrical water shell
attached below a carbide feed hopper. For larger scale plants, the dry generation design is more
common. This design features a continuous feed of carbide mixed with enough water to
complete the reaction and serve to dissipate the reaction exotherm. Acetylene production
technology is described in the report, including a pertinent process flow block diagram.
The oldest and simplest commercial route to VCM is via the vapor phase addition to acetylene
(C2H2) with anhydrous hydrogen chloride (HCl) over a mercuric chloride (HgCl2) catalyst
supported on activated carbon.
Acetylene and hydrogen chloride are used in a 1:1 molar ratio. A commercial process for the
production of VCM via acetylene/hydrogen chloride is described and schematically represented.
Ethylene-Based VCM
Commercial ethylene-based VCM technology utilizes direct chlorination of ethylene to produce
EDC, followed by pyrolysis to VCM and hydrogen chloride and oxychlorination to utilize the
hydrogen chloride.
Direct Chlorination
H2C=CH2 + Cl2 CH2ClCH2Cl
Ethylene 1,2 - Dichloroethane (EDC)
EDC Pyrolysis
CH2ClCH2Cl H2C=CHCl + HCl
EDC VCM
In the oxychlorination step, the hydrogen chloride released in pyrolysis is reacted with ethylene
(polymer grade) and oxygen (99.5 volume percent pure) to yield EDC and water:
CHEMSYSTEMS PERP PROGRAM 2
Report Abstract – Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC) 08/09-4
www.chemsystems.com
PERP ABSTRACTS 2009 00101.0009.4104
Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC)
The commercialization of oxychlorination technology paved the way for the “balanced process”,
combining direct chlorination, oxychlorination, and EDC pyrolysis reactions. This widely used
commercial process produces only VCM and water.
Using this balanced process (i.e., operating both the oxychlorination pathway and the direct
chlorination pathway), VCM can be produced from ethylene without incurring the problem of
hydrogen chloride disposal. The two processes operate synergistically and an efficient design
for the manufacture of vinyl chloride involves both processes.
A high proportion of VCM production capacity is based on this technology. However, a number
of producers operate unbalanced schemes drawing hydrogen chloride from other chlorination
operations in an adjacent plant. A further variation runs in part on EDC brought in from other
sources. Nevertheless, the balanced process is representative of the majority of the industry in
the developed regions.
Process description including pertinent process flow sheets for a generic balanced VCM
production plant highlighting Direct Chlorination, EDC Cracking, Purification,
Oxychlorination (catalyst, byproducts, fixed versus fluid-bed technology, air versus
oxygen technology, other technology aspects). VCM purification etc.
EDC
The chemical compound 1,2-dichloroethane, commonly known by its old name of ethylene
dichloride (EDC), is a chlorinated hydrocarbon, mainly used to produce VCM, the major
precursor for PVC production. It is a colorless liquid with a chloroform-like odor. EDC is also
used generally as an intermediate for other organic chemical compounds, and as a solvent.
In the direct chlorination process, EDC is produced by the exothermal addition of chlorine to
ethylene in liquid EDC phase. In the Vinnolit process, a special complex is used as catalyst.
Vinnolit-Uhde Boiling Reactor Technology including process flow diagram for the direct
chlorination operation is included in the report.
SAFETY, HEALTH AND ENVIRONMENTAL (SHE)
VCM is a gas with a molecular weight of 62.5 g/mol and boiling point of -13.9°C (7°F), and
hence has a high vapor pressure at ambient temperature. Therefore, it is manufactured under
strict quality and safety control.
Ethylene dichloride (EDC) is a clear, manufactured liquid that is not found naturally in the
environment. It is slightly soluble in water. The vapor pressure for EDC is 64 mm Hg at 20°C
(68°F). EDC is thermally stable at typical use temperatures. However, exposure to elevated
temperatures can cause the product to decompose.
Both ethylene dichloride and vinyl chloride are hazardous chemicals. Both are defined as
flammable, with vapors that can explode when mixed with air, and both are potentially damaging
to health.
CHEMSYSTEMS PERP PROGRAM 3
Report Abstract – Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC) 08/09-4
www.chemsystems.com
PERP ABSTRACTS 2009 00101.0009.4104
Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC)
In addition to health and environmentally related issues to VCM, EDC and their
production processes, this section pays particular attention to the significant and topical
environmental issues surrounding PVC.
RECENT DEVELOPMENTS
EDC and VCM production processes are exemplary of very mature industry segments. Nexant
has carried out a survey of selected patents from 2005 to the present.
ECONOMIC ANALYSIS
The cost of production estimates for the following are provided:
VCM produced by a commercial balanced oxychlorination process.
VCM produced from biotethylene - the cost of production of bioethylene via ethanol
dehydration and the cost of production of ethanol from corn are also provided.
VCM produced by the commercial acetylene-based route.
In some situations, EDC is produced for export, to support VCM and PVC production in regions
lacking an indigenous chlorine industry. EDC is more readily transported than chlorine, so
moving EDC is the preferred means of getting chlorine equivalents to remote regions.
A cost of production estimate for a stand-alone EDC facility employing direct
chlorination is presented.
Cost of production estimates for the VinTec boiling reactor process from Vinnolit show
the economic position of the VinTec process either as (a) a stand-alone EDC operation or
(b) as part of a balanced EDC/VCM operation.
Various sensitivities have been explored to illustrate the effects of variations in certain
parameters on the based case economics presented in the previous section. These results can
also be used to make approximate comparisons between cases for which detailed economics that
have not been provided by adjusting for capacity differences, alternative feedstock valuation, etc.
The sensitivity of the cost of production for VCM and EDC has been analyzed for pricing,
economy of scale, capital investment, and operating rate in this section.
COMMERCIAL ANALYSIS
Vinyl chloride monomer (VCM) is used almost exclusively to produce PVC. PVC can be used
in a multitude of applications by employing a number of fabrication methods including
extrusion, calendaring, injection molding, blow molding, and coating. Most PVC is processed
by extrusion to make pipe, siding and window or door profiles, wire and cable insulation and
rigid film or sheet. Other applications include chlorinated solvents and polyvinylidene chloride;
however the volumes involved are insignificant relative to PVC production.
EDC is consumed almost exclusively for VCM production. The remainder is consumed in the
manufacture of chlorinated solvents, lead alkyls, and adhesives. A majority of the EDC capacity
is integrated with VCM units on the same site.
CHEMSYSTEMS PERP PROGRAM 4
Report Abstract – Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC) 08/09-4
www.chemsystems.com
PERP ABSTRACTS 2009 00101.0009.4104
Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC)
VCM and EDC Supply, Demand and Trade for the United States, Western Europe and
Asia Pacific are discussed.
Tables giving extensive listings of specific plant capacity, company and location for each
of the regions denoted above are given.
CHEMSYSTEMS PERP PROGRAM 5
Report Abstract – Vinyl Chloride Monomer (VCM)-Ethylene Dichloride (EDC) 08/09-4
www.chemsystems.com
PERP ABSTRACTS 2009 00101.0009.4104
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