No. GB 2053452) and the chlorinated hydrocarbon waste inciner- ator, and more particularly to a method for modifying these systems such that a synthesized blend of carbon dioxide and oxygen replaces the ordinary air used to fuel the reaction in either system, thereby generating a useful hydrogen chloride product and a useful carbon dioxide product in both the VCR process unit and the chlorinated hydrocarbon waste incinera- tor. The invention further encompasses modifications to the anhydrous hydrogen chloride purification unit attached to these systems that prevent the discharge of any hydrochloric acid streams containing 3% by weight or greater hydrogen chloride dissolved in water. Furthermore, the invention encompasses the addition of absorbent beds to these systems that remove contaminants from the carbon dioxide product, with these contaminants ultimately being recycled back into the high temperature reactors, where they are converted to hydro- gen chloride and carbon dioxide. Also, the invention encom- passes the addition of a unit whereby oxygen that is present in the carbon dioxide exiting the absorbent beds is separated from the final carbon dioxide product stream and then recycled back into the high temperature reactor.

Background Art Chlorinated hydrocarbon by-product materials are gener- ated in a wide variety of chlorinated hydrocarbon manufactur- ing operations, such as the manufacture of ethylene dichloride, vinyl chloride monomer, methyl chloroform, tri- chloroethylene, perchloroethylene, allyl chloride or mono and dichlorobenzene. These are all commercial products, some of which may be used as solvents, others as feedstocks for pro- ducing materials such as non-ozone depleting refrigerants,

plastic film (e. g. Saran Wrap@), polyvinyl chloride, Teflon@, or Kynar. The chlorinated hydrocarbon by-products of these manufacturing operations have been traditionally considered hazardous wastes requiring carefully regulated treatment. One common method for treating these hazardous by-products is to destroy them in a chlorinated hydrocarbon waste incinerator.

In such systems, the liquid wastes are injected into a natural-gas fired incinerator, where the chlorinated organic molecules are essentially oxidized, thus yielding hydrogen chloride (HC1), salt water and a vent gas comprised mostly of nitrogen and carbon dioxide. An example of this type of system is depicted in Fig. 1.

Steam, or perhaps water, that is sometimes used to cool the reaction in these incinerators mixes with the hydrogen chloride, thus yielding a weaker hydrochloric acid by-product solution. This hydrochloric acid by-product, from 4% to 20% percent by weight hydrogen chloride, is too weak for typical commercial uses, which generally require acid strengths in excess of 31% by weight hydrogen chloride. Therefore, the useless hydrochloric acid by-product must be neutralized and disposed of as salt-water waste. Under federal guidelines, any unit producing an acid stream greater than 3% by weight hydrogen chloride must be classed as a halogen acid furnace (HAF) under the General Hazardous Waste Rules. This weak acid stream is therefore considered an undesirable waste product.

Furthermore, the predominately nitrogen/carbon dioxide waste gas generated in these incinerators is simply vented into the atmosphere. Some of the components present in the incinerator may also be converted into extremely toxic dioxin and into nitrous oxide, which may then appear in the vent gases. The fact that all by-products of the typical chlorinated hydrocar- bon incineration unit are un-useful, undesirable waste materi- als represents a disadvantage to this system.

The valorization of chlorinated residuals (VCR) process unit, similar to the incinerator described above, was designed specifically to produce at least one useful by-product of the typical chlorinated hydrocarbon oxidation technique that takes

place in an incinerator, namely anhydrous hydrogen chloride, although, of course the principles of the invention are appli- cable to other types of processes as well, including new facilities which are designed from the beginning to use the principles of the present invention. However, for exemplary purposes, the invention will be primarily discussed with respect to the particular BCP VCR facility described more fully below.

The VCR process unit, as employed by Borden Chemicals and Plastics (BCP) at Geismar, LA (USA), converts the chlorinated hydrocarbon by-product left over from the manufacture of vinyl chloride monomer into useful hydrogen chloride. One method for producing vinyl chloride monomer (VCM) entails reacting acetylene and anhydrous hydrogen chloride (HC1) as the raw materials for manufacturing the VCM product (see Fig. 2).

This process, as practiced by BCP, is termed the VCM-A Pro- cess. Another method for producing VCM entails reacting chlorine or anhydrous HC1 and ethylene to produce ethylene dichloride or 1,2 dichloroethane (EDC). The EDC is then thermally reacted to produce VCM (see Fig. 3). This process, as practiced by BCP, is termed the VCM-E Process. In both VCM processes, the chlorinated hydrocarbon by-product, also called organic intermediate materials, is generated. These organic intermediate materials consist primarily of the following chemical components: ethylene dichloride (CH2ClCH2Cl), trichloroethane (CHCl2CH2Cl), 1,1,2,2 tetrachloroethane (CHCl2CHCl2), 1, 1,1,2 tetrachloroethane (CHCl3CH2Cl), and pentachloroethane (CHCl2CCl3) Compounds such as chloroprene, 1,1 dichloroethane, 1,1,1 trichloroethane, chloroform, carbon tetrachloride, cis/trans- dichloroethylene, trichloroethylene, perchloroethylene and various other chlorinated organic compounds are also possible intermediate materials. These organic intermediate materials are further used as feedstock in the VCR process unit, whereby anhydrous HC1 is manufactured for use as a raw material feedstock for the VCM-A process described above. The VCR

process unit therefore serves as an HCl manufacturing unit using as feedstock the organic intermediate materials produced in the VCM-A and VCM-E processes, the intention being to maintain a"closed-loop"manufacturing process whereby all intermediate materials are usefully and beneficially utilized.

Thus, the VCR process unit is designed specifically to use the organic intermediate by-product of both VCM processes as a feedstock for manufacturing HC1, a necessary raw material in the VCM-A and VCM-E processes. The reaction taking place in the VCR process unit is depicted in Fig. 4. The system itself is depicted in Fig. 5.

The VCR process unit uses two raw materials for manufac- turing HCl, namely the organic feedstock and air. These raw materials are mixed in the VCR reactor, which contains a proprietary mixing device in which HCl is initially manufac- tured. In this mixing device, vaporized liquid feedstock is introduced into a high velocity, high temperature air stream.

The feedstock and the air react to form anhydrous HCl. The type of reactions that occur in the VCR process are repre- sented by the following equation: CHzClCH, Cl + CHC12CH2C'+ 4. 502 + N2--5HC1 + 4CO2 + 1-120 + N2 From the VCR reactor, the anhydrous HCl is directed into a purification unit and then used as feedstock in the VCM-A process. Excess water generated in the reactor must be purged from the system via this HC1 purification unit. Since this purge water contains greater than 3% by weight hydrogen chloride, thus constituting a weak acid stream, the VCR pro- cess unit is also classed as a halogen acid furnace. This weak acid purge must be neutralized to form salt water, which may then be sewered.

Meanwhile, a gaseous by-product, comprised mainly of CO2, N2, and minimal amounts of 02, HCl and C12, is directed into an alkaline-fed scrubbing unit, where any HCl and chlorine mole- cules are converted into salt water and then disposed of.

Remaining gases, comprised mainly of CO2, N2 and minimal amounts of 02, are vented to the atmosphere.

The VCR process unit attempts to achieve"closed system" status for the VCM manufacturing process by converting the chlorinated organic material into reusable HC1. The remaining by-products, such as the salt water created from the neutral- ization of the weak acid purge from the HC1 purification unit or from the alkaline-fed scrubbing unit, or the gaseous vent emissions comprised of CO2, N2, 02 have been historically considered environmentally harmless and thus suitable for release into the environment. However, recent concern about global warming and the need to reduce emissions of CO2, a greenhouse-effect gas, has prompted the U. S. EPA to look with scrutiny on chemical processes that needlessly vent CO2 to the atmosphere.

Furthermore, the weak acid purge from the HC1 neutraliza- tion unit is an undesirable waste product, as is the possible presence of dioxins inadvertently generated in the reactor that may appear in the vent gases.

A need exists, therefore, to modify the existing VCR process and the typical chlorinated hydrocarbon waste inciner- ator such that no CO2 is emitted to the atmosphere in the vent gas emissions from either system. The U. S. EPA, in carrying out the intentions and objectives of the Resource Conservation and Recovery Act (RCRA), has incorporated into the RCRA regu- lations certain rules and procedures to encourage chemical manufacturers to exploit as feedstocks for producing useful chemical products those intermediate materials that otherwise would be classified as hazardous waste materials. The EPA's ultimate goal is to achieve near 100% conversion of such intermediate materials into useful chemical products. This goal can be achieved by modifying existing chlorinated hydro- carbon waste incinerators and VCR process units such that no CO2 is emitted to the atmosphere because of the unnecessary introduction of N2 into the incinerator or the VCR. With no N2 being introduced into either system, the vent from both sys- tems becomes reasonably pure, marketable CO2, thus enabling essentially 100% beneficial utilization of the chlorinated organic intermediates.

A need also exists to modify the anhydrous HC1 purifica- tion unit attached to the VCR process unit such that the weak acid stream purged from the system contains 3% or less by weight hydrogen chloride. These modifications to the HC1 purification unit are also applicable to those HC1 purifica- tion units (herein termed"primary scrubbers") associated with chlorinated hydrocarbon waste incinerators.

A need further exists to modify the final gas vents in the VCR process unit and the chlorinated hydrocarbon waste incinerator such that undesirable compounds such as dioxins that might be present in the vent gases are captured before release to the atmosphere and destroyed within the system.

General Discussion of Invention The present invention is designed in one of its major aspects specifically to eliminate the N2 component of the final emission from, for example, the chlorinated hydrocarbon waste incinerator shown in Fig. 1 and, for further example, from the VCR process unit shown in Figs. 4 & 5. The present invention is also designed to eliminate, for example, an acid purge greater than 3% by weight hydrogen chloride from the anhydrous HC1 purification units attached to both systems. Furthermore, the present invention is designed inter alia to eliminate, for still further example, any trace contaminants, such as dioxin, from the vent gases of either system.

It is noted that oxygen (02) is the only component of air that is needed to react with the chlorinated organic materials in both systems in order either to destroy the molecules in the incinerator, or to manufacture anhydrous HC1 in the VCR process unit. Nitrogen (N2), an inert gas comprising roughly 78% of air, acts as a necessary diluent and coolant in the mixture that is fed into the incinerator and the VCR reactor.

The 02 component of the reaction taking place in either system preferably must not greatly exceed the normal 21% volume found in air, lest the reaction go unchecked and temperatures within the incinerator or the VCR reactor exceed specifica- tions. After the reaction, the N2 component, in the preferred embodiment, simply passes through the system, released in the

final emissions stage as an inert, useless vent component, mixed predominately with carbon dioxide (CO2), another inert gas. Since CO2 is an identified greenhouse-effect gas, and since the separation and purification of N2 and C02 in this vent stream would be a very expensive and an inefficient operation, the N2/CO2 vent stream is undesirable.

However, the inventor has surmised that a synthesized mixture of roughly 21% by volume 02 and 79% by volume C02 could be used in place of air in both the chlorinated hydro- carbon waste incinerator and the VCR reactor, thereby elimi- nating the undesirable N2 from the vent stream. This synthe- sized gas mixture could contain as much as 90% by volume CO2 and 10% by volume 02, or as little as 25% by volume C°2 and 75% by volume 02. However, the optimum mixture would likely contain from about 60% to about 80% by volume CO2, with 40% to 20% by volume 02 comprising the remaining percentage.

CO2, an inert gas, could essentially replace the diluent N2 in the feed air, thus providing the same diluent and non- reacting properties of the N2. The 02 in this mixture, essen- tially the same amount by volume as found in air, would effec- tively carry out the reaction with the chlorinated organic intermediates necessary to break down these chlorinated mole- cules, as in the incinerator, or to produce anhydrous HCl, as in the VCR reactor. The by-products of the reaction would therefore be comprised essentially of CO2 and a small amount of 02. Trace amounts of Cl2 and HCl in these emissions would still be eliminated in the alkaline scrubbing unit attached to either system, thereby producing a harmless salt water by- product. Other unwanted trace compounds, such as dioxin, can be eliminated from the vent gases through modifications that are described below. The remaining vent gas emission would therefore be predominately CO2 and a small amount of 02. In this way, no undesirable N2 would enter or leave the incinera- tor or the VCR process unit. The reaction employing a CO2/O2 mixture in place of air in the VCR process unit is shown in Fig. 6. The modified system using only the CO2/O2 mixture is

depicted in Fig. 7. The modified waste incinerator is de- picted in Fig. 8.

A further advantage exists in using CO2 as a diluent in the gaseous raw material fed into the VCR process unit and into the chlorinated hydrocarbon waste incinerator. Since CO2 is a necessary inert component to this raw material, the CO, that comprises the final emission from either system could then be reclaimed and reused to mix with 02 as the diluent in the gaseous raw material. In this way, the VCR process unit genuinely becomes a"closed-system,"wherein all end-products of the VCM and VCR processes are reused in the system.

No undesirable gases would therefore be released into the atmosphere. Excess CO2 generated as a result of the VCR process or the chlorinated hydrocarbon waste incinerator could further be used in any number of useful applications.

The modified chlorinated hydrocarbon waste incinerator, using only the synthesized CO2/O2 mixture, becomes a much improved, much more useful waste treatment system, since no undesirable greenhouse-effect exit gases are vented from the system, nor may undesirable by-products, such as nitrous oxide and dioxin be created and vented to the atmosphere. Instead, as in the VCR process unit, the CO2/O2 vent gas mixture may be reclaimed and recycled back into the incinerator, or the CO2 may be used in other processes. Since this CO2/02 mixture could also be used in place of water to cool the reaction in the incinerator, the hydrogen chloride by-product generated in the incinerator would be less diluted, and thus more economi- cally processable to anhydrous hydrogen chloride or strong commercial hydrochloric acid.

The VCR process unit contains an HCl purification unit, an example of which is depicted in Figs. 4 & 5. The purpose of this unit is to separate the CO2, N2 and 02 from the HCl and also to separate the HCl from the water, thus producing useful anhydrous hydrogen chloride product. However, the present VCR art practiced for example by BCP does not process all of the HCl produced in the VCR reactor into high purity anhydrous HCl. A small amount of weak hydrochloric acid, 18% to 20% by

weight hydrogen chloride, is produced and removed from the system to serve as the outlet for the water that is produced in the VCR reactor (see Fig. 9), and which must be purged from the system. Because of the production of this weak acid purge stream, BCP's VCR operation has been further classified by the EPA as a halogen acid furnace (HAF) under the General Hazard- ous Waste Rules.

Fig. 10 represents a proposed modification to the VCR HC1 purification scheme that eliminates the production of the halogen acid stream, thus achieving nearly 100% production of high purity anhydrous HCl gas from the HCl that is manufac- tured in the VCR reactor. Without the production of a halogen acid stream containing 3% or more of HCl, the VCR unit does not meet the specified criteria for a halogen acid furnace.

The modification to the VCR HCl purification system requires the addition of a distillation column to be used for the purpose of stripping water from a hydrochloric acid solu- tion containing from 14.5% to 19% by weight HCl. Such a stream can be produced by operating the HCl stripper at an elevated pressure. An operating pressure of 110 PSIG will permit the production of an underflow stream from the HCl stripper containing as little as 14.5% by weight HCl. Operat- ing the HCl stripper at such a pressure as will produce 18% by weight HCl underflow stream is suggested.

The inventor further suggests operating the water strip- ping column at pressures ranging from zero to near full vac- uum. At a pressure of zero PSIG, the underflow from the water stripping column should be approximately 20.2% by weight HC1 dissolved in water. The overhead from the water stripping column could be controlled to produce a water stream contain- ing very little HCl, definitely less than 3% by weight HC1.

The amount of water discharged from the top of the water stripping column will be determined by the amount of water produced in the VCR reactor. It is the opinion of the inven- tor that feeding into the water stripping column a stream containing 18% HCl and withdrawing an underflow stream from that column containing 20% HCl will normally permit the

removal of the needed amount of water from the system. If more water removal is required, the operating pressure of the HC1 column can be increased, thus lowering the HCl content of the underflow from that column. Another option would be to recycle a portion of the underflow from the water stripping column back into the HCl stripping column as a mid-column feed stream.

The technique described herein for removing water from a VCR process unit is applicable to situations where conven- tional chlorinated hydrocarbon waste incinerators are employed to manufacture high purity anhydrous HCl from chlorinated hydrocarbon waste materials.

Even when feeding a synthesized mixture of C02 and 02, instead of air, into VCR units or into conventional hazardous waste incinerators, there is still the possibility that minute amounts of undesirable compounds generated in the reactor, such as dioxin, will appear in the CO2 product stream. The inventor further proposes that absorbent beds capable of absorbing such components as dioxins be incorporated into the vent systems of the VCR process unit and the conventional chlorinated hydrocarbon waste incinerator systems to remove any trace quantities of such components that might be present in the CO2 product stream.

After leaving the HCl purification unit, this CO2 product stream preferably would be blown through a bed of absorbent material, such as activated carbon for example, or any number of suitable materials that readily absorb compounds such as dioxin. Said contaminants in the gas would be trapped within this absorbent material. Furthermore, the bottom portion of each absorbent bed can include some desiccant material capable of removing small amounts of water that otherwise would be present in the C02 stream exiting the bed. Clean, dry CO2 containing some amount of 02 would exit the downstream end of the bed. In time, the absorbent materials would become satu- rated with said contaminants and would thus require reactiva- tion, which could be accomplished by pumping a hot reactiva- tion gas through the bed to release the contaminants.

Since CO2 in this invention preferably is being recycled to produce a synthesized CO2/02 stream for feeding into VCR reactors or into hazardous waste incinerators, the inventor proposes reactivating the absorbent bed with some of the CO2 product that has been super-heated by steam. This reactiva- tion gas would then be passed through the spent bed to strip out dioxin or other such contaminants, and then the gas would be routed back into the high temperature incinerator or VCR reactor where said contaminants would be oxidized, and essen- tially destroyed. In this way no contaminants would ever leave the VCR process unit or the chlorinated hydrocarbon waste incinerator.

Fig. 11 depicts two absorbent beds installed in parallel that can be used to clean the CO2 product, while at the same time preventing in total the escape to the environment of any toxic compounds such as dioxins that might be present in gases exiting a VCR reactor or a hazardous waste incinerator. The optimal design of such a system would employ at least two absorbent beds in parallel so that one bed could be cleaning the CO2 product while the other bed is in reactivation service.

Additionally, it is anticipated that these two modified systems for processing chlorinated hydrocarbons can be located near or adjacent to facilities utilizing CO as feedstock, such as plants manufacturing urea, a vital component in fertilizer, or plants that manufacture methanol, or plants for producing silicon dioxide pigment, or other such CO consuming opera- tions.

Excess CO2 generated in either system might also be purified and used for such things as inert purging and padding gas for systems handling, for example, flammable materials and for producing carbonated beverages. Thus, finally, as an optional, supplemental process, a sub-system for separating out undesired 02 from the product CO2 stream for optional use in conjunction with the HCl purification system of the inven- tion is provided.

A further aspect of the present invention includes using a unit whereby the C°2, which contains some amount of °21

exiting the absorbent beds is compressed to a relatively high pressure and then passed through, for example, the tubes of a shell-and-tube, heat exchanger, which has on the shell side of the exchanger liquid CO2 boiling at a lower pressure. The cold boiling CO2 on the shell side of the heat exchanger condenses the high pressure CO2 passing through the tubes, thus producing a stream containing liquid C02, 02 in solution with the liquid CO2, and free 02 gas. This stream is fed into a column where, for example, hot compressor discharge gas is used to apply heat to the liquid CO2 at the bottom of the column, thus driving the dissolved 02 up and out the top of the column. The 02 rich stream exiting the top of the oxygen stripping column can be recycled back into the high temperature reactor, e. g. the incinerator. The vaporized oxygen free CO2 stream, as it exits the shell side of the heat exchanger is heated with, for example, hot compressor discharge gas, thus producing heated, high quality pipeline CO2 product. Since this CO2 product stream contains essentially no °21 it can be used, for example, as a reactivation gas for absorbent beds utilizing activated carbon as the absorbent material. Reactivating an absorbent bed containing dioxins will likely require a reactivation temperature higher than that which can be achieved using steam as the source of heat. Heating CO2 reactivation gas in a furnace fired with the natural gas possibly would enable the achievement of a temperature sufficient for reactivating absorbent beds containing dioxin.

Another approach for accomplishing reactivation would be to use carbon as the absorbent material, enrich the CO2 reacti- vation gases with °2 and then heat this gaseous mixture with steam in, for example, a shell and bulb heat exchanger prior to feeding it into the bed being reactivated. Raising the termperature of 02 enriched CO2 to 250° F would ignite the carbon within the bed which would vaporize the dioxin and drive it out of the bed along with the very hot CO2 exit gas that is routed back into the combustion chamber of the incin- erator. This approach would consume some carbon during each

reactivation, thus requiring the addition of make-up absorbent carbon after, for example, each reactivation.

Also included in this invention is a simplified, inte- grated process and system for converting chlorinated hydrocar- bon by-products into useful anhydrous HC1 gaseous products and useful CO2 gaseous product with zero discharge of anything to the environment, in a process that completely meets the objec- tives of the Resource Conservation and Recovery Act (RCRA) or its equivalent. This can be done using a method and system for modifying conventional hazardous waste, incinerator units or VCR units for producing high purity HC1 gas and high purity CO2 gas with zero discharge of any materials to the environ- ment. The present invention also includes a method and system for building and operating new (vis-a-vis modifying conven- tional) incinerator units and new VCR units that will produce from chlorinated by-products high purity HC1 and high purity CO2 with zero discharge of any material to the environment.

It is further noted, with respect to some of the forego- ing, that the present invention includes inter alia : 1. Modifications that can be made to the VCR process, which is now a process used for the purpose of destructing chlorinated hydrocarbon materials that have been classified by the EPA as hazardous waste materials, such that these materi- als would no longer be classified as hazardous waste materials because: a) The materials would be used in total to produce feedstocks that would be further used to produce other market- able products. The production of water and a very miner amounts of salt is acceptable. The key is to convert essen- tially all the carbon, chloride and hydrogen contained in the chlorinated hydrocarbon by-products into useful HC1 and useful CO2. b) No stream would be produced that contained more than 3% by weight HC1 in water. If a stream is produced having3% or more by weight of HC1 in water, the process as defined in the RCRA regulations is classified as halogen acid furnace and all materials so processed is subject to a hazard-

ous waste tax. With no acid produced containing greater than 3% percent HCl in water, the modified VCR process unit can not be classified as a halogen acid furnace. c) There would be no vents to the atmosphere. with the absorbent beds removing water and any possible contami- nants from the CO2 product and those contaminants ultimately being recycled back into the VCR reactor, there is zero dis- charge to the environment of such things as dioxin. The outstanding thing about the process is that what is now con- sidered very hazardous chlorinated hydrocarbon waste would be processed in a manner such that the environmental impact would be zero.

2. Modifications that can be made to conventional hazard- ous waste incinerators used for the destruction of materials classified by the EPA as very hazardous chlorinated hydrocar- bon waste materials such that those materials would no longer be classified as such, because: a) The materials would be used in total to produce feedstocks that would be further used to produce other market- able products. The production of water and a very miner amounts of salt is acceptable. The key is to convert essen- tially all the carbon, chloride and hydrogen contained in the chlorinated hydrocarbon by-products into useful HCl and useful CO2. b) No stream would be produced that contained more than 3% by weight HCl in water. If a stream is produced having 3% or more by weight of HCl in water, the process as defined in the RCRA regulations is classified as halogen acid furnace and all materials so processed is subject to a hazard- ous waste tax. With no acid produced containing greater than 3k percent HCl in water, the modified VCR process unit can not be classified as a halogen acid furnace. c) There would be no vents to the atmosphere. With the absorbent beds removing water and any possible contami- nants from the C02 product and those contaminants ultimately being recycled back into the VCR reactor, there is zero dis- charge to the environment of such things as dioxin. The

outstanding thing about the process is that what is now con- sidered very hazardous chlorinated hydrocarbon waste would be processed in a manner such that the environmental impact would be zero.

Any conventional hazardous waste incinerator modified in accordance with the principles of the present invention should become units highly suitable for processing materials contain- ing such things as PCBs (polychlorinated bi-phenyls). Also, hazardous waste incinerators incorporating some of the modifi- cations contained in this invention should be entirely suit- able for destructing chemicals manufactured for chemical warfare. Things such as N-mustard compounds and S-mustard compounds could be totally and safely destroyed by employing the absorbent bed technique that is incorporated herewith into the list of suggested modifications for conventional hazardous waste incinerators. Right now, there is a desperate need for a reliable and satisfactory method that the United States Department of Defense can use to destruct a huge quantity of unneeded and unwanted N-mustard and S-mustard.

Additionally, as will become clear from the following detailed description, other highly innovative, unobvious advances and improvements are also disclosed as part of the present invention.

Brief Description of Drawings For a further understanding of the nature and objects of the present invention, reference should be had to the follow- ing detailed description, taken in conjunction with the accom- panying drawings, in which like elements are given the same or analogous reference numbers, and wherein: Fig. 1 is a schematic, generalized view of a typical, prior art chlorinated hydrocarbon waste incinerator system.

Fig. 2 is a schematic, flow chart view of the exemplary reaction taking place in an exemplary, prior art, vinyl chlo- ride monomer-acetylene (VCM-A) manufacturing unit.

Fig. 3 is a schematic, flow chart view of the exemplary reaction taking place in an exemplary, prior art, vinyl chlo- ride monomer-ethylene (VCM-E) system.

Fig. 4 is a schematic, flow chart view of the exemplary reactions taking place in a typical, prior art, air-fed valo- rization of chlorinated residuals (VCR) process unit.

Fig. 5 is a schematic, generalized flow chart view of the exemplary feed mechanisms for an exemplary, prior art, air-fed valorization of the chlorinated residuals (VCR) process unit.

Fig. 6 is a schematic, generalized flow chart view of the exemplary reactions taking place in a VCR process unit modi- fied for a synthesized CO2/O2 feed in accordance with the principles of the present invention.

Fig. 7 is a schematic, generalized flow chart view of the exemplary feed mechanism for a CO2/O2-fed VCR unit, such as that shown in Fig. 6.

Fig. 8 is a schematic, generalized flow chart view of the exemplary chlorinated hydrocarbon waste incineration system modified for a synthesized CO2/O2 feed in accordance with principles of the present invention.

Fig. 9 is a simplified flow diagram of an exemplary, prior art HCl purification system as found in the VCR process unit.

Fig. 10 is a simplified flow diagram of the exemplary HCl purification system modified in accordance with the principles of the present invention.

Fig. 11 is a schematic of exemplary absorbent beds for removing contaminants from the CO2 product generated in the VCR process unit or a chlorinated hydrocarbon waste incinerator.

Fig. 12 is a simplified flow diagram and schematic for an exemplary, optional, preferred process and system for separat- ing out undesiredO2 from the product CO2 stream for optional use in conjunction with the HCl purification system of the invention.

Fig. 13 is a simplified flow diagram and schematic of the exemplary integrated process for producing, from chlorinated hydrocarbon by-products, high purity HCl gaseous product and high purity CO2 gaseous product with zero discharge of pollut- ants to the environment, including no discharge of dioxins, green-house gases or NOX gases.

Description of the Preferred, Exemplary Embodiment Fig. 1: The typical chlorinated hydrocarbon waste incin- erator system is shown. The system is comprised of a central, high-temperature incinerator into which natural gas, chlori- nated liquid wastes and process gaseous wastes are injected, along with combustion air. The controlled natural gas flame burns within the incinerator. There is a port adjacent to this flame wherein steam or water can be injected to cool the reaction. A primary scrubber is attached downstream of the incinerator, wherein hydrogen chloride is dissolved in water to produce a weak acid solution. A secondary scrubber con- taining an alkali solution is attached downstream of the primary scrubber in order to neutralize any HCl or chlorine still contained in the vent gas. The remaining CO2/N2 gas is vented from this secondary scrubber.

Fig. 2: The reaction taking place in a vinyl chloride monomer-acetylene (VCM-A) manufacturing unit is depicted. In this unit, acetylene is reacted with anhydrous HCl to produce vinyl chloride monomer. Chlorinated organic intermediates are

shown as a by-product of this reaction. They may be used in a valorization of chlorinated residuals (VCR) process unit. The chemical equation showing the reaction of acetylene with HCl is also depicted.

Fig. 3: The reaction taking place in a vinyl chloride monomer-ethylene (VCM-E) system is depicted. In one unit, chlorine and ethylene are reacted to produce ethylene dichloride (EDC) in a liquid phase direct chlorination tech- nique. Chlorinated organic intermediates are by products of this reaction and may be fed into a VCR process unit. In another unit, anhydrous HCl is reacted with ethylene and 02 to produce EDC in a gas phase oxyhydrochlorination technique.

The EDC manufactured in the liquid and gas phase units is fed into the VCM-E manufacturing unit to produce the vinyl chlo- ride monomer product. Chlorinated organic intermediates are generated in each unit, and may be fed into a VCR process unit. The basic chemical equation for the VCM-E process is also shown.

Fig. 4: The reactions taking place in a typical air-fed valorization of chlorinated residuals (VCR) process unit are depicted. In this unit, chlorinated organic intermediates (i. e. chlorinated hydrocarbon by-products of the VCM-A and VCM-E processes) are fed with air into the VCR unit, where the chlorinated molecules are oxidized, thus yielding anhydrous HCl, trace amounts of C12, carbon dioxide, nitrogen, and small amounts of oxygen and water vapor. This yield is passed into an HCl purification unit, from which purified anhydrous HCl is removed. Some salt water leaves this unit, while remaining vent gases are passed through a neutralization unit. In the neutralization unit, alkaline wash water neutralizes any remaining HCl and chlorine in the vent gas, turning it into waste salt water. The remaining,"clean"carbon dioxide/nitrogen gas mixture is vented from this unit. The basic chemical equation for this process is also shown.

Fig. 5: The feed mechanisms for an air-fed valorization of chlorinated residuals (VCR) process unit is depicted. The unit consists primarily of a reactor, into which vaporized

chlorinated organics are injected into a mixing device with a controlled feed of high velocity, high temperature air.

Natural gas (CH4) is used only during start-up of the unit.

From the mixing device, the high-temperature organic interme- diate/air mixture enters the reactor itself, where oxidation of the chlorinated compounds takes place. Secondary air ports, whence additional diluent air is drawn into the reac- tor, are also depicted. The anhydrous HC1, CO2, N2,02, and water vapor exits the reactor, passing through the HC1 purifi- cation unit, and neutralization unit described in Fig. 4.

Fig. 6: The reactions taking place in a VCR process unit modified for a synthesized C02/01 feed are depicted. In this modified system, a synthesized mixture comprised of approxi- mately 79k CO2 and 21t °2 is mixed with chlorinated organic intermediates and then injected into the VCR reactor. The resulting anhydrous HC1, CO2, °2, and water vapor product is passed into the HC1 purification unit, where anhydrous HC1 is removed. Some salt water exits this purification unit. The remaining CO2 gas, containing trace amounts of HC1 and chlo- rine, is passed through a neutralization unit, where an alka- line wash is used to neutralize any remaining HC1 and chlorine from the C02, converting them into salt water. The nearly pure CO2, is then collected as it exits the neutralization unit, where it may be used as CO2 product, or mixed with pure °2 in a synthesizing unit. The mixture from the synthesizing unit is then fed back into the VCR reactor.

Fig. 7: The feed mechanism for a CO2/O2-fed VCR unit is depicted. The unit includes primarily a reactor into which chlorinated organic intermediates are injected, along with a high-velocity, high-temperature controlled feed of CO2/O2.

These components are mixed and injected into the reactor unit, where oxidation of the chlorinated compounds takes place. The synthesized CO2/O2 mixture is further drawn into secondary ports to act as a diluent to the reaction. Note that no air is either fed into, nor drawn into this modified system. The anhydrous HC1, CO2, 02, and water vapor mixture is passed into the HC1 purification unit, where nearly pure anhydrous HC1 is

removed. Some salt water exits this unit. CO2, and small amounts of °21 HC1 and Cl2 exit the purification unit and pass through the neutralization unit, where an alkali wash neutral- izes any HC1 and chlorine molecules, turning them into salt water. Then, the nearly pure CO2 product is collected from the neutralization unit, where it may be used in other processes, or blended with 02 in a high pressure surge drum, whence the synthesized blend may be drawn for the controlled feed.

Additional synthesized CO2/02 mixture is drawn from the surge drum and stored just above atmospheric pressure in a tank for feed into the secondary (diluent) CO2/O2 ports in the reactor.

Fig. 8: The chlorinated hydrocarbon waste incineration system modified for a synthesized C02/O2 feed is depicted. In this system, chlorinated liquid wastes and process gaseous wastes are injected along with the natural gas fuel and the CO2/O2 combustion mixture into the incinerator. Chlorinated molecules are broken down (oxidized) in a controlled flame within the incinerator. Recycled CO2 is injected adjacent to this controlled flame for cooling purposes. Downstream of the incinerator, a primary scrubber removes most hydrogen chloride from the by-product blend exiting the incinerator, yielding an acid solution that may be purified for further use or neutral- ized for disposal. A secondary scrubber downstream of the primary scrubber removes any remaining chlorine molecules from the vent gas, yielding salt water and a nearly pure CO2 vent product. This vent product may then be mixed with pure 02 in a synthesizing vessel and re-injected into the incinerator.

Fig. 9: The simplified flow diagram of an HC1 purifica- tion system as found in the VCR process unit is depicted. In this system, a gaseous mixture comprised of mostly HC1, CO2 and water vapor is passed into the HC1 Absorber from the VCR reactor. This absorber removes nearly all of the HC1 from the gaseous mixture, which then exits the absorber in solution with water at approximately 33% by weight HC1. CO2 containing a small amount of 02 is vented from this absorber. The 33% by weight HC1 acid stream is pumped into an HC1 stripper where HC1 is separated from the solution, yielding 100% anhydrous

HC1 gas. An approximately 9% percent by weight HC1 acid solution is withdrawn from the bottom of the HC1 stripper with most of the stream being recycled back to the HCl absorber. A small portion of the 19% HCl recycle stream is purged from the system to remove excess water generated in the VCR reac- tor. This diagram is also applicable to the HCl purification unit attached to a chlorinated hydrocarbon waste incinerator.

Fig. 10: The simplified flow diagram of a modified HCl purification system as found in the VCR process unit is de- picted. In this system, a gaseous mixture comprised of mostly HC1, C02 and water vapor is passed into the HCl Absorber from the VCR reactor. This absorber removes nearly all of the HCl from the gaseous mixture, which then exits the absorber in solution with water at approximately 3% by weight HCl. CO2 containing a small amount of 02 is vented from the Absorber.

The 33% by weight HCl acid stream is pumped into an HCl stripper maintained under high pressure where HCl is separated from the solution, yielding 100% anhydrous HCl gas. High pressure operation of the HCl Stripper permits the production of an underflow stream containing less than 19% HC1, the normal being approximately 18% by weight HCl. The 18% per- cent HCl stream is then fed into the water stripping column, which is operated at zero PSIG or vacuum pressure. Essen- tially pure water is distilled overhead from the water strip- ping column, thus producing an underflow stream of 20% to 21% by weight HCl in water. The entire underflow from the water stripping column is recycled back to the HCl absorber.

Fig. 11: The schematic of absorbent beds for removing contaminants from the C02 product generated in a VCR process unit or a chlorinated hydrocarbon waste incinerator is de- picted. In this system, CO2 from the HCl purification unit is directed into an Absorbent Bed No. 1, where contaminants such as dioxin are absorbed from the CO2. The clean CO product is exited from the downstream end of the absorbent bed. The clean CO2 may then be used for other operations requiring CO2.

An Absorbent Bed No. 2 is installed in parallel with Absorbent Bed No. 1. It is used to clean the CO2 product in like manner

while the first Absorbent Bed is being reactivated (i. e. while trapped contaminants are removed from the bed through the introduction of a hot CO2 reactivation gas heated in a natural gas fired heater or in the case of a bed charged with carbon absorbent, a hot CO2 gas stream enriched with 02 being heated by high pressure steam). Note that CO2 generated within the system is employed as the reactivation gas, thereby keeping all products within the system. A reactivation stream bearing contaminants is routed from the reactivated Absorbent Bed back into the VCR reactor, where contaminants are destroyed. A system of valves within the system of Absorbent Beds directs the proper flow of CO2 product or reactivation materials. The CO2 feed stream entering an absorbent bed will contain a low level of water. The bottom portion of each absorbent bed preferably includes a desiccant material for removing water from the CO2, thus producing a dry, purified CO2 exit stream.

Fig. 12: The simplified flow scheme of a process for separating °2 from CO2 is depicted. The scheme comprises a unit whereby the CO2, which contains some amount of 02 exiting the absorbent beds, is compressed to a relatively high pres- sure and then passed through, for example, the tubes of a shell-and-tube, heat exchanger which has on the shell side of the exchanger liquid CO2 boiling at a lower pressure. The relatively low temperature boiling CO2 on the shell side of the heat exchanger condenses the high pressure CO2 passing through the tubes thus producing a stream containing liquid CO2 and 02 in solution with the liquid CO2 and free °2 gas. This stream is fed into a column where, for example, hot compressor dis- charge gas is used to apply heat to the liquid CO2 at the bottom of the column thus driving the dissolved 02 up and out the top of the column. The 02 rich stream exiting the top of the oxygen stripping column can be recycled back into the high temperature reactor. The vaporized oxygen free CO2 stream as it exits the shell side of the heat exchanger is heated with hot compressor discharge gas thus producing heated high qual- ity pipeline CO2 product. Since this CO2 product stream con- tains essentially no °2, it possibly can be used as a reactiva-

tion gas for absorbent beds utilizing activated carbon as the absorbent material if the CO2 is heated to, for example, 2,000° F or greater in a natural gas fired heater.

Fig. 13: The simplified, integrated process, flow scheme for producing, from chlorinated hydrocarbon by-product, high purity gaseous HC1 product and gaseous CO2 product is depicted.

The process discharges no environmentally harmful materials to the environment and completely meets the objectives of RCRA.

The integrated process involves manufacturing a synthetic mixture of CO2 and 02 in vessel V-100. This synthetic mixture of C02/O2 is properly mixed with the chlorinated hydrocarbon by-products and fed into a high temperature reactor (s), for example, an incinerator R-100 or a VCR unit R-101.

Exiting the high temperature reactor R-100/R-101 is a gas stream consisting of HC1, CO2, H20 vapor and 0.. After cooling (cooling step not shown), this stream is fed into the bottom of the HC1 absorber V-101 where the HC1 is absorbed into weak acid [approximately 20% in strength] which is fed into the top of V-101. Strong acid [approximately 33% 1 is pumped from the bottom of absorber V-101 and fed into the top of the high pressure HC1 stripper V-102. Steam heat is applied to the bottom of stripper V-102, thus resulting in the overhead stripping of approximately 54-55% of the HC1 fed into stripper V-102. Normally, the high pressure HC1 gas produced in strip- per V-102 will be used for producing ethylene dichloride in oxyhydrochlorination reactors and for producing vinyl chloride monomer in VCM-A reactors.

The underflow from the stripper V-102, approximately 15% in strength, is fed into the top of the water stripper V-103, where water is distilled overhead by applying steam heat to the bottom of the column. Enough water is distilled overhead in the stripper V-103 to produce an under-flow stream approxi- mately 20% in strength. This 20% percent stream is recycled back into the top of absorber V-101. (Within the HC1 absorp-

tion and stripping system, heat removal, which is not shown, is required.) Carbon dioxide exiting absorber V-101 and containing 4-10k °2 and trace quantities of HC1 and chlorine is fed into the bottom of the Neutralizer V-104, where the gas is scrubbed with an alkaline solution to neutralize the trace quantities of HC1 and chlorine. CO2 with some amount of 02 present exits the top of neutralizer V-104 and is fed into compressor C-1, where the pressure is raised to a level sufficient for recy- cling CO2 into vessel V-100 and for passing the stream through the CO2 clean-up beds V-105 and V-106.

Un-purified CO2 containing some °2 is fed through clean-up bed V-105 while V-106 is being reactivated or visa-versa.

Clean-up beds V-105 and V-106 are charged with activated carbon or some other material capable of removing trace con- taminants, such as dioxin, from the CO2 stream. The bottom portion of each CO2 clean-up bed likely will need to be charged with a desiccant material capable of removing the low levels of water that will be present in the gas stream entering the beds. Upon exiting the active clean-up bed V-105/V-106, depending on which clean-up bed is in service, purified dry CO2 containing some °2 is fed into compressor C-2, where the pressure is elevated to, for example, approximately 250 PSIG and then routed through the tube side of the CO2 condenser/vaporizer E-100. As the high pressure gas passes through the tubes, the CO2 condenses taking some 02 into solu- tion. Condensed C°2, 02 in solution and gaseous 02 are passed into the 02 stripper V-107. The bottom of V-107 is heated with hot gas exiting compressor C-2, thus driving the 02 dissolved in the liquid CO2 up and out the top of V-107. The 02 rich stream exiting the top of stripper V-107 is recycled back into vessel V-100. Oxygen free CO2 is withdrawn from the bottom of V-107, where it is routed into the shell side of heat exchanger E-101. The shell side of heat exchanger E-101 is

maintained at a pressure well below the discharge pressure of compressor C-2, thus permitting COz to vaporize in the shell of condenser/vaporizer E-100 at a temperature low enough to condense the CO2 flowing through the tubes. As the purified vaporized CO2 exits the shell of condenser/vaporizer E-100, it is heated with the hot gas discharged from compressor C-2 and then is marketed as high purity CO2 pipeline product. A portion of the high purity C02 product is routed through the heat exchanger E-101, where it is heated to a sufficient temperature to reactivate either clean-up bed V-105 or V-106, which ever bed is being reactivated. As the hot CO2 passes through the bed being reactivated, dioxin and other such compounds are stripped from the beds and routed back through the high temperature reactor where they are destroyed. Also, the water captured by the water removing desiccant within the bed is stripped from the bed and routed back into the reactor.

Fig. 13 thus depicts a method for modifying conventional hazardous waste incinerators units or VCR units for producing high purity HCl gas and high purity CO2 gas with zero discharge of any harmful materials to the environment. It also depicts a methods for building and operating new incinerator units and new VCR units that will produce from chlorinated by-products high purity HC1 and high purity CO2 with zero discharge of any harmful material to the environment.

It is noted that the embodiments described herein in detail for exemplary purposes are of course subject to many different variations in structure, design, application and methodology. Because many varying and different embodiments may be made within the scope of the inventive concept (s) herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the de- scriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.