VCM

Technical Process Scheme for VCM Production by Ethylene Oxychlorination

1. Product Scheme
1.1 Product Scheme
This plant adopts the balanced ethylene oxychlorination process for vinyl chloride production, comprising the following units: direct chlorination, oxychlorination, EDC purification, EDC cracking, and VCM purification.
1.2 Product Quality Specifications
The technical specifications of the vinyl chloride product meet the requirements of HG/T 6065-2022 Vinyl Chloride for Industrial Use — Ethylene-based Process.

2. Vinyl Chloride Production Process

（1）Reaction Mechanism
Direct chlorination:

C₂H₄ + Cl₂ → C₂H₄Cl₂ + 218 kJ/mol

Oxychlorination: 

C₂H₄ + 2HCl + ½O₂ → C₂H₄Cl₂ + H₂O + 238 kJ/mol

EDC cracking: 

C₂H₄Cl₂ → C₂H₃Cl + HCl − 71 kJ/mol

（2） Process Block Diagram

Figure 1 VCM Process Block Diagram

（3）Process Description
The VCM plant consists of the following units: oxychlorination, EDC recovery, EDC purification and high-temperature direct chlorination, EDC cracking, VCM purification, refrigeration, HCl emergency neutralization, EDC tank farm, VCM tank farm, wastewater collection and treatment, off-gas incineration, and inside/outside battery limit piping. The process flow for each unit is described below:
1）Oxychlorination Unit
Hydrogen chloride containing a small amount of acetylene from the VCM purification unit is heated and then fed to the hydrogenation reactor, where it reacts with hydrogen from outside the battery limits to form ethylene and ethane. It is then introduced, together with preheated fresh oxygen, to the bottom of the oxychlorination reactor. The other feed stream to the oxychlorination reactor bottom is a mixture of preheated fresh ethylene and recycle gas.
In the oxychlorination reactor, ethylene, oxygen, and hydrogen chloride undergo a highly exothermic reaction over the catalyst to produce EDC and water.
The oxychlorination reactor is operated at a temperature of 220–240℃and a pressure of 0.25–0.3 MPa(g). Cooling coils are installed inside the reactor to generate steam and remove the heat of reaction, thereby ensuring precise temperature control and minimizing the formation of by-products as well as corrosion caused by hot spots and cold spots. The reaction gas leaves the reactor from the top and enters the quench tower, where it is washed with water to remove unreacted hydrogen chloride. The scrubbed hydrogen chloride and the water generated from the reaction are withdrawn from the bottom of the hot quench tower and sent to the wastewater treatment unit.
The gas from the top of the quench tower is then sent to the crude EDC condenser, where a large portion of EDC and water is condensed. The liquid phase obtained in the crude EDC condensate separator is crude EDC, which is sent to the EDC recovery unit. Most of the gas phase is recycled as recycle gas, while a small portion is sent to the EDC recovery unit for deep cooling. The recycle gas is compressed, heated, mixed with fresh ethylene, and then returned to the oxychlorination reactor.
2）EDC Recovery Unit
Crude EDC from the oxychlorination unit first enters the CO₂ stripping tower, where it is stripped with a small amount of nitrogen to remove dissolved CO₂. The stripped gas, together with a small portion of the cooled vent gas, is sent to the vent gas deep cooler for further condensation of EDC and water. The non-condensable gases from the deep cooling separation are discharged to the tail gas incinerator.
After stripping, the crude EDC passes sequentially through a water wash tank and a caustic wash tank to remove impurities. The washed wet crude EDC is then sent by a storage tank to the EDC purification unit. The aqueous phase from the water wash is returned to the hot quench tower as circulating wash water. The aqueous phase from the caustic wash is mostly recycled, with a small portion sent to the wastewater treatment unit.
3）EDC Purification and High-Temperature Direct Chlorination Unit
The EDC purification unit consists of three distillation towers-the heads tower, the heavy-ends tower, and the vacuum tower-along with their associated auxiliary equipment. This unit separates water, light components, and heavy components from the crude EDC, and supplies purified EDC to the EDC cracking furnaces.
In the heads tower, water and light chlorinated hydrocarbon components (lighter than EDC) in the wet crude EDC from the EDC recovery unit are separated by distillation, sent to the tank farm for storage, and then forwarded to the incinerator. The dry crude EDC from the heads tower bottom, together with the recycle EDC from the VCM purification unit, enters the heavy-ends tower. Integrated with this tower is a reactor that produces EDC by high-temperature direct chlorination of ethylene. The heat of reaction from chlorine and ethylene is utilized to supply the energy required for the operation of the heavy-ends tower, achieving significant energy savings compared to using a steam reboiler.
Chlorine and ethylene are fed to the high-temperature direct chlorination (HTDC) reactor under flow control. The chlorine concentration in the EDC vapor leaving the reactor is strictly controlled by a chlorine analyzer. Iron chloride is generated in a post-reaction bed containing iron packing, which is located in the upper section of the reactor. The ferric chloride produced in the post-reaction bed is transferred to the reactor to enhance EDC formation and reduce by-product formation.
During normal operation, the heat provided by the high-temperature direct chlorination (HTDC) reactor is sufficient to meet the heat requirements of the heavy-ends tower. A reboiler is used for start-up or shutdown operations.
The overhead distillate from the heavy-ends tower is condensed and returned to the tower as reflux by pump. EDC product is withdrawn as a side draw from a tray located several trays below the top. After cooling, the EDC product is pumped to an intermediate storage tank for use as feedstock to the EDC cracking furnaces.
Uncondensed vapors from the reflux drum are sent to a refrigerated tail gas condenser for further EDC recovery. The off-gas from the tail gas condenser, containing non-condensable gases such as ethylene and oxygen, is compressed by the HTDC tail gas compressor to 0.67 MPa(g) and sent to the oxychlorination unit. The recovered EDC light components are sent to the caustic wash tank in the EDC recovery unit for caustic washing and subsequent recovery.
The bottoms from the HTDC reactor-tower system are sent to the vacuum tower.
In the vacuum tower, heavy components from the heavy-ends tower bottoms and the cracking section purge are concentrated in the tower bottom and sent to the tank farm for temporary storage before being forwarded to the incinerator. EDC recovered from the vacuum tower overhead distillate is sent to the EDC cracking furnaces.
4）EDC Cracking Unit
Purified EDC is cracked at elevated temperature and pressure to produce VCM and HCl:
Purified EDC is fed to the EDC cracking furnace, where it is thermally cracked into VCM and hydrogen chloride. The pyrolysis reaction takes place in a gas-fired box-type furnace at a temperature of 480–490℃ and a pressure of 1.0 MPa(g). Currently, the high-efficiency cracking furnace achieves a thermal efficiency of over 90%. The cracking furnace operates at low pressure, with the vapor-phase feed entering the cracking section. The EDC conversion rate is 55%. The low-pressure vapor-phase feed cracking furnace ensures high on-stream time, requiring no decoking for more than one year.
A heat recovery system - the transfer line exchanger (TLE) - is installed at the cracking furnace outlet to recover the substantial energy contained in the furnace effluent stream. This heat recovery system generates 2.0 MPa steam, which is used entirely for heating the EDC vaporizer.
The cracking furnace effluent is further cooled in the quench tower using recycle EDC and overhead-condensed VCM. The quench tower bottoms are sent to the quench tower bottoms stripper to recover hydrogen chloride and VCM from the stream. The liquid and vapor streams from the quench section are fed to different trays of the HCl tower in the VCM purification unit for further separation.
5）VCM Purification Unit
The VCM purification unit mainly consists of three distillation tower systems: the HCl tower, the VCM tower, and the VCM stripper. The vapor and liquid streams from the EDC cracking unit are fed to different trays of the HCl tower. A portion of the HCl tower overhead is condensed by refrigerated liquid and returned as reflux (at - 41℃). The hydrogen chloride leaving the HCl tower overhead is sent to the oxychlorination unit after heat exchange to recover cooling duty. The HCl tower bottoms are sent to the VCM tower, where VCM is separated from unreacted EDC. The VCM product from the VCM tower overhead is sent to the VCM stripper to strip out residual hydrogen chloride, and is then sent to the spherical storage tanks in the tank farm. The VCM tower bottoms, after passing through the light ends chlorinator, are sent to the dry EDC storage tank and recycled to the EDC purification unit.
6）Refrigeration Unit
The refrigeration unit provides various grades of refrigerant to the plant. The refrigerant used in this project is propylene, which supplies two grades of chilled propylene at 1.7℃and -41℃.
In consideration of emergency releases of propylene and ethylene from the refrigeration unit, a ground flare is provided within the battery limits for the treatment of ethylene and propylene under emergency conditions.
7）HCl Emergency Neutralization Unit
The HCl emergency neutralization system, which handles releases from safety valves and manual valves, is a passive system that uses a pre-stored sufficient quantity of caustic soda solution for neutralization. The 32% caustic soda solution from the outside battery limits is diluted to 20% in the caustic storage tank, and is then charged, together with demineralized water, into the HCl neutralization tank, where the caustic concentration is approximately 7%. The neutralization tank is always ready to receive hydrogen chloride released from the HCl tower and other sources. Unabsorbed gases are vented to the incineration system, while the spent caustic solution containing absorbed hydrogen chloride is collected in the waste liquor storage tank and then sent to the wastewater stripping system for pretreatment.
The hydrogen chloride gas generated from the incineration system is absorbed, concentrated, and decolorized to produce by-product hydrochloric acid, which is collected and then transferred by pump to the loading/unloading area.
8）EDC Tank Farm
The EDC tank farm includes dry EDC storage tanks, wet crude EDC storage tanks, dry crude EDC storage tanks, EDC feed buffer tanks, light component tanks, and heavy component storage tanks.
The wet crude EDC storage tank mainly receives wet crude EDC from the caustic wash tank, which is then recycled to the heads tower of the EDC purification unit for treatment. If the heads tower liquid level is too high, the bottoms from the tower may also be temporarily routed to this tank. The dry crude EDC storage tank receives dry crude EDC from the VCM tower bottoms by the chlorinator, as well as crude EDC collected from safety relief systems, and sends it to the heavy-ends tower of the EDC purification unit for treatment. The dry EDC storage tank receives purified EDC from the heavy-ends tower and the vacuum tower, and supplies it to the cracking furnaces. The heavy component storage tank receives bottoms from the vacuum tower of the EDC purification unit and sends them to the incinerator. The light component storage tank receives water and chlorinated hydrocarbons lighter than EDC from the wet crude EDC in the EDC recovery unit, and sends them to the incinerator.
9）VCM Tank Farm
The VCM liquid from the VCM stripper bottom, after passing through the VCM product cooler, is sent to the VCM product spherical tanks and then delivered by pump to the PVC plant. Off-spec VCM is sent to the off-spec VCM spherical tank and then returned to the VCM purification unit for reprocessing.
10）Wastewater Collection and Treatment Unit
Berms (containment dikes) shall be provided in all areas throughout the plant where chlorinated organics may overflow or leak. Any water from these bermed areas (initial rainwater, wash water, floor flushing water, etc.) is collected in trenches, sent to the sewage storage tank, pretreated in the wastewater treatment system, and then sent outside the battery limits for further treatment.
Organics from out-of-service equipment are collected in a dedicated wastewater collection header within the trench and conveyed to the process wastewater sump in the wastewater collection pit. Similarly, the wastewater is pumped to the sewage tank, treated in the wastewater treatment system, and then sent outside the battery limits for further treatment.
The wastewater treatment system uses corrosion-resistant agitated tanks. The wastewater undergoes a two-stage neutralization process, with acid or alkali added as required to ensure pH control. After neutralization, a conventional steam stripping tower is used to remove organic contaminants and recover EDC from the neutralized wastewater.
11）Tail Gas Incineration Unit
Off-gases from the VCM plant under both normal and abnormal operating conditions—which may contain components such as VCM, EDC, hydrogen chloride, propylene, oxygen, ethylene, and chlorine—are all sent to the incineration unit for treatment. The light components (water and chlorinated hydrocarbons lighter than EDC) separated from the wet crude EDC in the heads tower from the EDC recovery unit are also sent to the incineration unit. In addition, the heavy components concentrated in the vacuum tower bottoms from the heavy-ends tower bottoms and the cracking section purge are likewise sent to the incineration unit for disposal.
The incineration unit employs advanced and proven chlorinated waste incineration technology, mainly comprising the following systems: waste gas pretreatment, incineration, waste heat recovery, quench and absorption, caustic scrubbing and neutralization, and flue gas exhaust. The system produces 2.0 MPa(g) saturated steam and 18–20 wt% hydrochloric acid as by-products. The dilute hydrochloric acid is further concentrated, decolorized, and dechlorinated to produce 31% industrial hydrochloric acid, which is sent to the hydrochloric acid tank farm. The treated tail gas is discharged to atmosphere meeting emission standards, while the neutralized wastewater is sent to the sewage storage tank. The specific process flow is as follows:
Dry and wet off-gases are separately routed to the off-gas buffer tank for surge control, and then conveyed by ejectors to the incinerator burners. Off-gases from the oxychlorination unit are directly fed to the burner by ejectors. Intermittent off-gases are sent directly to the burner for combustion. The incineration temperature is controlled at 1300℃. Under negative pressure and oxygen-rich conditions at high temperature, the waste gases are thoroughly decomposed and oxidized to CO₂, H₂O hydrogen chloride, and other products. The flue gas also contains large amounts of N₂, some excess O₂, and trace amounts of free Cl₂. A continuously burning pilot flame is maintained in the incinerator to prevent flameout caused by fluctuations in waste gas flow. The incinerator uses natural gas as auxiliary fuel, with combustion air supplied by a forced draft fan. The incineration temperature is maintained by the combustion of fuel and waste materials. The burners are of low-NOx design, ensuring that NOx in the flue gas meets emission standards without the need for further treatment.
Waste Heat Recovery System: The high-temperature flue gas from the incinerator contains a large amount of thermal energy. It first passes through a waste heat boiler to recover the usable energy from the flue gas, generating 2.0 MPa(g) saturated steam which is sent to the steam header. While recovering the sensible heat of the flue gas, the formation of dioxins from chlorinated organics must be avoided. At an incineration temperature above 1300℃, the dioxin destruction efficiency exceeds 99.9%. However, the temperature window for dioxin reformation during cooling is 550℃to 250℃. Therefore, the waste heat boiler outlet temperature is set at 550–600℃. After passing through the waste heat boiler, the flue gas temperature is reduced from 1300℃to approximately 550℃, which not only avoids the dioxin reformation temperature window but also remains well above the maximum flue gas dew point of hydrogen chloride (108.6℃), thereby preventing HCl dew-point corrosion.
Quench and Absorption System: After heat recovery in the waste heat boiler, the flue gas enters the quench tower for rapid cooling. In the quench tower, the flue gas is rapidly cooled from 550–600℃to below 80℃, with a cooling time far less than the national standard requirement of <1s, thereby minimizing dioxin formation within the system. In the quench tower, the flue gas comes into direct contact with atomized circulating dilute hydrochloric acid for heat and mass transfer. A portion of the hydrogen chloride is absorbed by the circulating liquid. The absorption process is exothermic, while the evaporation of water from the dilute acid circulation absorbs a large amount of thermal energy from the flue gas. At the same time, sensible heat transfer between the circulating dilute acid and the flue gas also contributes to the rapid temperature reduction. This quenching process also creates favorable conditions for isothermal absorption in the falling film absorber, enabling the production of a higher-concentration by-product hydrochloric acid.
The flue gas exiting the quench tower then enters the falling film absorber, where it flows countercurrently to the circulating dilute hydrochloric acid. In the falling film absorber, hydrogen chloride gas is dissolved into the dilute acid, and water vapor is condensed into liquid. Since both the dissolution of hydrogen chloride gas and the condensation of water vapor are exothermic processes, the heat released is removed by circulating cooling water flowing through the shell side of the falling film absorber. The hydrochloric acid generated from the bottom of the falling film absorber is collected in the dilute acid circulation tank for recirculation to the quench tower and the falling film absorber. Once the circulation absorption reaches equilibrium, the by-product acid meeting the required concentration is continuously discharged from the circulation tank, while a portion continues to be recirculated for absorption of hydrogen chloride from the flue gas.
Tail Gas Purification System: The flue gas exiting the falling film absorber, with its hydrogen chloride content greatly reduced, enters the caustic scrubbing system. In the caustic scrubber, the flue gas undergoes final high-efficiency scrubbing with a 5% NaOH solution to neutralize the residual hydrogen chloride and absorb any free chlorine, ensuring that the flue gas meets the national emission standards.
Tail Gas Discharge: After the caustic scrubbing and neutralization system, the flue gas emission indicators are better than the relevant requirements of national environmental standards. The flue gas is drawn by the induced draft fan to the stack and discharged to the atmosphere at high elevation. A flue gas analyzer is installed on the flue gas pipeline to monitor the flue gas composition.

3. Technical Advantages
3.1 Advantages of the Oxychlorination Process
Compared with other technologies, the main advantages of the oxygen-based oxychlorination process are as follows:
1.Operational flexibility, ease of operation, and safety. The reactor feed rate can be easily varied from 40% to 110% of the design value without compromising efficiency or product purity. The recommended dedicated catalyst provides a wider operating window and flexibility without concerns about catalyst stickiness. Unlike fixed-bed technology, operating parameters remain stable, eliminating the need for constant adjustments to feed rates, temperature profiles, etc. This makes operation stable and optimization simpler and more effective.
2.A safe and reliable ESD system. The reactor operates in a lean-oxygen / fuel-rich mode within the recycle gas. Three oxygen analyzers are connected to the ESD system through a 2-out-of-3 voting arrangement. Compared with other technologies that use only one or two analyzers, this approach offers greater safety and reliability, with a lower probability of spurious shutdowns.
3.Feedstock flexibility. Polymerization-grade or impure ethylene, as well as oxygen from cryogenic or PSA units, can be used. Dry HCl feed from other sources can also be utilized.
4.Indefinite catalyst life in the fluidized bed. There is no need for periodic catalyst replacement as required by fixed-bed technology. This reduces downtime and production losses. There are no complex loading procedures, no diluents required, and the catalyst cost over the plant life cycle is very low. The pressure drop issues commonly encountered in fixed-bed systems are eliminated.
5.The reactor and reactor cooling coils are constructed of carbon steel. This results in lower capital investment and eliminates the possibility of stress corrosion cracking associated with the use of stainless steel in other technologies. Operating experience has demonstrated that this material is fully acceptable when proper external insulation and measures are applied to control dew-point corrosion. Other technologies use more expensive materials and/or have difficulty maintaining steam tracing of the reactor and cooling coils.
6.Highly efficient and economical CO₂ removal is achieved through nitrogen stripping and caustic washing, resulting in a non-corrosive EDC product and allowing downstream equipment to be constructed of carbon steel. In other technologies, CO₂ removal is less efficient, necessitating the use of corrosion-resistant materials for downstream processing equipment.
7.Caustic soda consumption is very low, limited only to the caustic required for neutralizing unreacted HCl. Other technologies use caustic soda for CO₂ removal from the recycle gas, which can result in up to 10 times higher caustic consumption.
3.2 Advantages of the High-Temperature Direct Chlorination Process
Compared with other technologies, the main advantages of the high-temperature direct chlorination process are as follows:
1.100% efficient recovery of direct chlorination reaction heat. The vaporized EDC is fed directly to the heavy-ends tower, where it is utilized for distillation of all EDC streams in the unit.
2.No steam is required for EDC distillation to remove heavy components.
3.Natural circulation in the HTDC reactor. The HTDC reactor system is free of expensive, complex, and potentially unreliable pumps, and has no moving parts.
4.Easy start-up and long-term reliable operation. Load turn down to 30%–40% of the design value is readily achievable.
5.Inexpensive in-situ iron catalyst system. No special catalyst storage, addition, or activation equipment or procedures are required.
6.Maintenance during plant turnarounds requires only inspection and replacement of iron packing every two to three years.
7.The high-velocity distributor design ensures efficient dissolution of ethylene and chlorine, resulting in very high reaction efficiency.
8.In the HTDC reactor, ethylene used as a diluent gas is completely recovered and fully utilized in the oxychlorination reaction, achieving very high ethylene efficiency.
3.3 Advantages of the Cracking and VCM Purification Process
Compared with other technologies, particularly high-pressure cracking, the main advantages of the low-pressure cracking and VCM purification process are as follows:
1.Very low by-product formation, particularly of butadiene, chloromethane, and chloroethane.
2.Safer operation of the low-pressure cracking furnace and quench tower.
3.The EDC vapor fed to the cracking furnace is generated in a separate steam vaporizer, which can be easily taken out of service for cleaning with high-pressure water.
4.Low coking rate, enabling furnace run lengths of more than one year.
5.No iron carryover from the EDC vaporizer to the cracking furnace feed.
6.Ability to use a variety of fuels for firing the furnace. Natural gas, fuel gas, LPG, and even vaporized light hydrocarbons (such as naphtha) have all been used successfully.
7.Elimination of superheating, with the quench tower containing trays to minimize coke carryover.
8.The efficient quench tower bottoms stripper, used for HCl and VCM recovery and coke removal, eliminates the troublesome quench tower bottoms flash two-stage evaporation system commonly employed in other technologies. This system offers low investment and maintenance costs and simplifies operation.
9.Efficient heat recovery from the hot cracking furnace effluent for steam generation. Approximately 200,000 kcal of heat can be recovered per ton of VCM product to generate high-pressure steam.
10.A very low reflux ratio on the VCM tower, due to the small amount of by-products requiring removal. This results in lower investment and operating costs compared with high-pressure cracking processes.
11.No caustic washing or solid caustic scrubber is required, as upstream stripping removes residual HCl from the VCM product stream.
12.Less corrosion and high operational reliability.
13.The VCM stripper overhead stream is recycled to the HCl tower, thereby increasing hydrogen chloride recovery.
14.No VCM product inspection tank is required, as an online analyzer continuously monitors the VCM product purity.
15.Chlorination of light fractions in the recycle EDC stream eliminates the need for a separate light-ends distillation tower. This results in significant savings in capital investment and steam consumption.
3.4 Production Cost Advantages
1.Low capital investment - The initial capital investment is minimized, as the majority of equipment in the plant is constructed of carbon steel. Costs are further reduced by minimizing the number of components, equipment sizes, and piping complexity.
2.Large single-train capacity. Only the cracking furnace requires two trains.
3.High conversion, high selectivity, and high efficiency reduce raw material consumption, which is the main component of production cost.
4.Low by-product yield in the process reduces VCM losses and minimizes the costs associated with by-product disposal.
5.Utility and chemical costs are reduced through the following measures:
(1) Low power consumption, particularly for the oxychlorination recycle gas compressor.
(2) Low fuel gas consumption due to the high thermal efficiency of the EDC cracking furnace.
(3) Reduced steam consumption through heat recovery.
(4) Elimination of the light-ends tower reduces capital investment, maintenance costs, and steam and cooling water consumption.
(5) Low-pressure cracking reduces impurity formation, allowing the VCM tower to operate at a low reflux ratio, thereby reducing cooling water and steam consumption.
(6) Use of the HTDC process eliminates the steam required to drive the heavy-ends tower.
(7) Proper design of the oxychlorination reactor feed system and cyclone separators results in very low catalyst loss.
(8) The use of the CO₂ stripping tower for oxychlorination EDC product reduces caustic consumption in the EDC washing line.
(9) The quench tower bottoms stripper recovers HCl and VCM from the quench tower purge stream, which would otherwise be sent to the incinerator and lost.
3.5 Heat Recovery Advantages
1.Heat is recovered and reused at multiple points in the process. The largest sources of heat recovery are the high-temperature direct chlorination (HTDC) reactor and the cracking furnace transfer line exchanger (TLE).
2.The HTDC process allows all of the reaction heat from the direct chlorination reaction to be recovered as the heat load for the heavy-ends tower. This completely eliminates the need to supply steam to the heavy-ends tower reboiler.
3.The cracking furnace effluent TLE generates high-pressure steam by recovering heat from the hot gases leaving the furnace.
4.Other areas where heat recovery is possible include: the incineration unit, the cracking furnace quench tower overhead, the cracking furnace stack flue gas, the light-ends chlorination system (through exchange between VCM tower bottoms and heavy-ends tower feed), the MTDC stripper feed heat exchanger, the wastewater stripper feed heat exchanger, and steam generation through condensate recovery and flashing.
3.6 Quality Advantages
1.The low-pressure cracking process generates very low levels of impurities. This results in a significantly reduced volume of liquid by-products requiring treatment, and facilitates easier disposal. More importantly, the purification of the VCM product becomes simpler due to the lower impurity content.
2.The low level of impurities requiring removal allows the VCM tower to operate at a very low reflux ratio. This minimizes capital investment and significantly reduces the steam and cooling water consumption required for tower operation.
3.The HCl stripping technology removes any residual HCl from the VCM product stream, eliminating the need for a caustic washing or solid caustic scrubbing system.
3.7 Operating Cycle Advantages
Typically, the cracking furnace operates for 14 to 18 months. The oxychlorination reactor can normally run for 18 months. The HTDC reactor can operate for 24 to 36 months. Most distillation towers can operate for 2 years. For reboilers that are prone to fouling, spare reboilers are provided to ensure that the unit operating time is not limited during reboiler cleaning.

4. Main consumption indicators

5. Main Raw Material Supply

 (1) Ethylene
  The ethylene quality shall meet the requirements for first-grade product as specified in GB/T 7715-2014 Ethylene for Industrial Use.

(2) Chlorine
The chlorine quality shall meet the specifications listed in the following table.

(3) Oxygen
The oxygen quality shall meet the requirements of GB/T 3863-2008 Oxygen for Industrial Use.

(4) Hydrogen
The hydrogen quality shall meet the requirements for first-grade product as specified in GB/T 3634.1-2006 Hydrogen for Industrial Use.

6. List of Major Equipment