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Home , Petrochemical

Prevention and Abatement Handbook WORLD BANK GROUP Effective July 1998

Petrochemicals

Industry Description and Practices A number of alternative methods for manufac- turing the desired products are available. Details and crude distillates such as naph- on typical processes and products are provided tha from refining are used as feed- in the Annex. stocks to manufacture a wide variety of petrochemicals that are in turn used in the manu- Waste Characteristics facture of consumer goods. The description of petrochemical processes and products presented Fugitive air emissions from pumps, valves, here is for illustrative purposes only. The basic flanges, storage tanks, loading and unloading petrochemicals manufactured by , re- operations, and wastewater treatment are of forming, and other processes include olefins greatest concern. Some of the compounds re- (such as , propylene, butylenes, and leased to air are carcinogenic or toxic. Ethylene ) and aromatics (such as , tolu- and propylene emissions are of concern because ene, and ). The capacity of crack- their release can lead to the formation of ex- ers is generally of the order of 250,000–750,000 tremely toxic oxides. Compounds considered metric tons per year (tpy) of ethylene production. carcinogenic that may be present in air emissions Some petrochemical plants also have and include benzene, butadiene, 1,2-dichloroethane, oxo-compound manufacturing units on site. The and . A typical naphtha cracker at base petrochemicals or products derived from a petrochemical complex may release annually them, along with other raw materials, are con- about 2,500 metric tons of , such as pro- verted to a wide range of products. Among them pylenes and ethylene, in producing 500,000 met- are: ric tons of ethylene. Boilers, process heaters, flares, and other process equipment (which in • and such as low-density poly- some cases may include catalyst regenerators) are ethylene (LDPE), high-density responsible for the emission of particulates, car- (HDPE), linear low-density polyethylene bon monoxide, nitrogen oxides (200 tpy), based (LLDPE), , , and on 500,000 tpy of ethylene capacity, and sulfur (PVC) oxides (600 tpy). • Synthetic such as and acrylic The release of volatile organic compounds • such as (VOCs) into the air depends on the products butadiene (ABS) handled at the plant. VOCs released may include • Rubbers, including styrene butadiene rubber acetaldehyde, , benzene, , trichlo- (SBR) and rubber (PBR) roethylene, trichlorotoluene, and . VOC • emissions are mostly fugitive and depend on the • Industrial chemicals, including those used production processes, materials-handling and for the manufacture of such as lin- effluent-treatment procedures, equipment main- ear alkyl benzene (LAB) and of , - tenance, and climatic conditions. VOC emissions stuffs, agrochemicals, pharmaceuticals, and from a naphtha cracker range from 0.6 to 10 kilo- explosives. grams per metric ton (kg/t) of ethylene pro-

371 372 PROJECT GUIDELINES: SECTOR GUIDELINES duced. Of these emissions, 75% consists of al- cesses are usually specific to the characteristics kanes, 20% of unsaturated hydrocarbons, about of the products manufactured. Specific pollution half of which is ethylene, and 5% of aromatics. prevention or source reduction measures are best For a vinyl chloride plant, VOC emissions are determined by technical staff. However, there are 0.02–2.5 kg/t of product; 45% is ethylene dichlo- a number of broad areas where improvements ride, 20% vinyl chloride, and 15% chlorinated are often possible, and site-specific emission re- organics; for an SBR plant, VOC emissions are 3– duction measures in these areas should be de- 10 kg/t of product; for an ethyl benzene plant, signed into the plant and targeted by plant 0.1-2 kg/t of product; for an ABS plant, 1.4–27 management. Areas where efforts should be con- kg/t of product; for a styrene plant, 0.25–18 kg/t centrated are discussed below. of product; and for a polystyrene plant, 0.2–5 kg/t of product. Petrochemical units generate Reduction of Air Emissions wastewaters from process operations such as va- por condensation, from blowdown, • Minimize leakages of volatile organics, includ- and from stormwater runoff. Process wastewa- ing benzene, vinyl chloride, and ethylene ox- ters are generated at a rate of about 15 cubic ide, from valves, pump glands (through use of meters per hour (m3/hr), based on 500,000 tpy mechanical seals), flanges, and other process ethylene production, and may contain biochemi- equipment by following good design practices cal demand (BOD) levels of 100 mg/l, as and equipment maintenance procedures. well as chemical oxygen demand (COD) of 1,500– • Use mechanical seals where appropriate. 6,000 mg/l, suspended solids of 100–400 mg/l, • Minimize losses from storage tanks, product and and grease of 30–600 mg/l. levels transfer areas, and other process areas by of up to 200 mg/l and benzene levels of up to 100 adopting methods such as vapor recovery sys- mg/l may also be present. tems and double seals (for floating roof tanks). Petrochemical plants generate solid wastes • Recover catalysts and reduce particulate and sludges, some of which may be considered emissions. hazardous because of the presence of toxic or- • Reduce nitrogen oxide (NOx) emissions by ganics and heavy metals. Spent caustic and other using low-NOx burners. Optimize fuel usage. hazardous wastes may be generated in signifi- cant quantities; examples are residues In some cases, organics that cannot be recov- associated with units handling acetaldehyde, ered are effectively destroyed by routing them acetonitrile, benzyl chloride, tetrachlo- to flares and other combustion devices. ride, , phthallic anhydride, , methyl ethyl pyridine, , Elimination or Reduction of Pollutants trichloroethane, , perchloroeth- ylene, , , dimethyl hydra- • Use nonchrome-based additives in cooling zine, ethylene dibromide, toluenediamine, . , ethyl chloride, ethylene dichlo- • Use long-life catalysts and regeneration to ex- ride, and vinyl chloride. tend the cycle. Accidental discharges as a result of abnormal op- eration, especially from polyethylene and ethyl- Recycling and Reuse ene-oxide-glycol plants in a petrochemical complex, can be a major environmental hazard, • Recycle cooling water and treated wastewa- releasing large quantities of pollutants and prod- ter to the extent feasible. ucts into the environment. Plant safety and fire pre- • Recover and reuse spent solvents and other vention and control procedures should be in place. chemicals to the extent feasible.

Pollution Prevention and Control Improved Operating Procedures

Petrochemical plants are typically large and com- • Segregate process wastewaters from storm- plex, and the combination and sequence of pro- water systems. Petrochemicals Manufacturing 373

• Optimize the frequency of tank and equipment densation, absorption, adsorption (using acti- cleaning. vated carbon, silica gel, activated alumina, and • Prevent solids and oily wastes from entering zeolites), and, in some cases, biofiltration and the drainage system. bioscrubbing (using peat or heather, bark, com- • Establish and maintain an emergency pre- posts, and bioflora to treat biodegradable organ- paredness and response plan. ics), and thermal decomposition.

Target Pollution Loads Liquid Effluents

Implementation of cleaner production processes Petrochemical wastewaters often require a com- and pollution prevention measures can yield both bination of treatment methods to remove oil and economic and environmental benefits. The fol- other contaminants before discharge. Separation lowing production-related targets can be of different streams (such as stormwater) is es- achieved by measures such as those described in sential to minimize treatment requirements. Oil the previous section. The figures relate to the pro- is recovered using separation techniques. For duction processes before the addition of pollu- heavy metals, a combination of oxidation/reduc- tion control measures. tion, precipitation, and filtration is used. For or- A good practice target for petrochemical com- ganics, a combination of air or steam stripping, plex is to reduce total organic emissions (includ- granular activated carbon, wet oxidation, ion ing VOCs) from the process units to 0.6% of the exchange, reverse osmosis, and electrodialysis is throughput. Target maximum levels for air re- used. A typical system may include neutraliza- leases, per ton of product, are, for ethylene, 0.06 tion, coagulation/flocculation, flotation/sedi- kg; for , 0.02 kg; for vinyl chloride, mentation/filtration, biodegradation (trickling 0.2 kg; and for 1,2-dichloroethane, 0.4 kg. Meth- filter, anaerobic, aerated lagoon, rotating biologi- ods of estimating these figures include ambient cal contactor, and activated sludge), and clarifi- and emissions monitoring, emission factors, and cation. A final polishing step using filtration, inventories of emissions sources. Design assump- ozonation, activated carbon, or chemical treat- tions should be recorded to allow for subsequent ment may also be required. Examples of pollut- computation and reduction of losses. ant loads that can be achieved are: COD, less than Vapor recovery systems to control losses of 1 kg per 100 tons of ethylene produced; sus- VOCs from storage tanks and loading areas pended solids, less than 0.4 kg/100 t; and dich- should achieve close to 100% recovery. loroethane, than 0.001 kg/100 t. A wastewater generation rate of 15 cubic meters per 100 tons of ethylene produced is Solid and Hazardous Wastes achievable with good design and operation; and new petrochemical complexes should strive to Combustion (preceded in some cases by achieve this. extraction) of toxic organics is considered an ef- fective treatment technology for petrochemical Treatment Technologies organic wastes. Steam stripping and oxidation are also used for treating organic waste streams. Air Emissions Spent catalysts are generally sent back to the sup- pliers. In some cases, the solid wastes may re- Control of air emissions normally includes the quire stabilization to reduce the leachability of capturing and recycling or combustion of emis- toxic metals before disposal of in an approved, sions from vents, product transfer points, stor- secure landfill. age tanks, and other handling equipment. Catalytic cracking units should be provided Emissions Guidelines with particulate removal devices. Particulate re- moval technologies include fabric filters, ceramic Emissions levels for the design and operation of filters, wet scrubbers, and electrostatic precipi- each project must be established through the tators. Gaseous releases are minimized by con- environmental assessment (EA) process on the 374 PROJECT GUIDELINES: INDUSTRY SECTOR GUIDELINES basis of country legislation and the Pollution Pre- Table 2. Effluents from Petrochemicals vention and Abatement Handbook, as applied to lo- Manufacturing cal conditions. The emissions levels selected must (milligrams per liter, except for pH and temperature) be justified in the EA and acceptable to the World Parameter Maximum value Bank Group. The guidelines given below present emissions pH 6–9 levels normally acceptable to the World Bank BOD 30 Group in making decisions regarding provision COD 150 TSS 30 of World Bank Group assistance. Any deviations Oil and grease 10 from these levels must be described in the World Cadmium 0.1 Bank Group project documentation. The emis- Chromium (hexavalent) 0.1 sions levels given here can be consistently Copper 0.5 achieved by well-designed, well-operated, and Phenol 0.5 well-maintained pollution control systems. Benzene 0.05 The guidelines are expressed as concentrations Vinyl chloride 0.05 Sulfide 1 to facilitate monitoring. Dilution of air emissions Nitrogen (total) 10 or effluents to achieve these guidelines is unac- Temperature increase ≤ 3°Ca ceptable. All of the maximum levels should be achieved for at least 95% of the time that the plant Note: Effluent requirements are for direct discharge to surface or unit is operating, to be calculated as a propor- . a. The effluent should result in a temperature increase of no tion of annual operating hours. more than 3° C at the edge of the zone where initial mixing and dilution take place. Where the zone is not defined, use 100 Air Emissions meters from the point of discharge.

The emissions levels presented in Table 1 should be achieved. Solid Wastes and Sludges

Liquid Effluents Wherever possible, generation of sludges should be minimized. Sludges must be treated to reduce The effluent levels presented in Table 2 should toxic organics to nondetectable levels. Wastes be achieved. containing toxic metals should be stabilized be- fore disposal. Table 1, Emissions from Petrochemicals Manufacturing and Target Ambient Levels Ambient Noise (miligrams per normal cubic meter) Parameter Maximum value Noise abatement measures should achieve either the levels given below or a maximum increase in PM 20 Nitrogen oxides 300 background levels of 3 decibels (measured on the chloride 10 A scale) [dB(A)]. Measurements are to be taken Sulfur oxides 500 at noise receptors located outside the project Benzene 5 mg/m3 for emissions; property boundary. 0.1 ppb at the plant fence 1,2-dichloroethane 5 mg/m3 for emissions; Maximum allowable log 1.0 ppb at the plant fence equivalent (hourly Vinyl chloride 5 mg/m3 for emissions; measurements), in dB(A) 0.4 ppb at the plant fence Day Night 3 15 mg/m Receptor (07:00–22:00) (22:00–07:00) Note: Maximum ambient levels for ethylene oxide are 0.3 parts per billion (ppb) at the plant fence. Maximum total emissions of Residential, the VOCs acetaldehyde, , benzyl chloride, carbon institutional, tetrachloride, chlorofluorocarbons, ethyl acrylate, halons, ma- educational 55 45 leic anhydride, 1, 1, 1 trichlorethane, trichloroethylene, and trich- Industrial, lorotoluene are 20 mg/Nm3. Maximum total heavy metals emissions are 1.5 mg/Nm3. commercial 70 70 Petrochemicals Manufacturing 375

Monitoring and Reporting • Use nonchrome-based additives in cooling water. Frequent sampling may be required during start- • Design and practice emergency preparedness up and upset conditions. Once a record of con- and prevention measures. sistent performance has been established, sampling for the parameters listed in this docu- Annex. Typical Processes and Products ment should be as described below. in Petrochemical Manufacturing Air emissions from stacks should be visually monitored for opacity at least once every eight C1 compounds (with one carbon atom in their hours. Annual emissions monitoring of combus- molecule) manufactured at petrochemical plants tion sources should be carried out for sulfur ox- include , , and haloge- ides, nitrogen oxides, and the organics listed nated hydrocarbons. Formaldehyde is used in the above, with fuel sulfur content and excess oxy- manufacture of resins, including phenolic, gen maintained at acceptable levels during nor- , and melamine resins. Halogenated hydro- mal operations. Leakages should be visually are used in the manufacture of silicone, checked every eight hours and at least once a solvents, refrigerants, and degreasing agents. week using leak detection equipment. Olefins (organics having at least one double Liquid effluents should be monitored at least bond for carbon atoms) are typically manufac- once every eight hours for all the parameters cited tured from the of hydrocarbons above except metals, which should be monitored such as naphtha. Major olefins manufactured in- at least monthly. clude ethylene (C2, since it has two carbon atoms),

Each shipment of solid waste going for dis- propylene (C3), butadiene (C4), and acetylene. The posal should be monitored for toxics. olefins manufactured are used in the manufac- Monitoring data should be analyzed and re- ture of polyethylene, including low-density poly- viewed at regular intervals and compared with ethylene (LDPE) and high-density polyethylene the operating standards so that any necessary (HDPE), and for polystyrene, polyvinyl chloride, corrective actions can be taken. Records of moni- (used along with dimethyl toring results should be kept in an acceptable terphthalate, DMT, as feedstock to the polyester format. The results should be reported to the manufacturing process), (used as responsible authorities and relevant parties, as solvents), polyvinyl acetate (used in plastics), required. polyisoprene (used for manufac- ture), polypropylene, acetone (used as a solvent and Key Issues in ), isopropanol (used as a solvent and in pharmaceuticals manufacturing), acrylonitrile (used in the manufacture of acrylic fibers and The key production and control practices that will nitrile rubber), (used in phar- lead to compliance with emissions guidelines can maceuticals manufacturing), and . be summarized as follows: Butadiene is used in the manufacture of • Implement an equipment maintenance pro- polybutadiene rubber (PBR) and styrene butadi-

gram that minimizes releases of volatile organ- ene rubber (SBR). Other C4 compounds manu- ics, including ethylene oxide, benzene, vinyl factured include butanol, which is used in the chloride, and 1,2-dichloroethane. manufacture of solvents such as methyl ethyl • Install vapor recovery systems to reduce VOC ketone. emissions. The major aromatics (organics having at least

• Use low-NOx burners. one ring structure with six carbon atoms) manu- • Optimize fuel usage. factured include benzene, toluene, xylene, and • Regenerate and reuse spent catalysts, solvents, naphthalene. Other aromatics manufactured in- and other solutions to the extent feasible. clude phenol, , styrene, phthalic • Recycle cooling water and reuse wastewaters. and maleic anhydride, nitrobenzene, and aniline. • Segregate stormwater from process waste- Benzene is generally recovered from cracker water. streams at petrochemical plants and is used for 376 PROJECT GUIDELINES: INDUSTRY SECTOR GUIDELINES the manufacture of phenol, styrene, aniline, ni- Sources trobenzene, sulfonated detergents, pesticides such as hexachlorobenzene, (an im- Bounicore, Anthony J., and Wayne T. Davis, eds. 1992. portant intermediate in synthetic manufac- Air Pollution Engineering Manual. New York: Van ture), and , used in the manufacture Nostrand Reinhold. of . Benzene is also used as a solvent. Cortes, Mariluz, and Peter Bocock. 1984. North-South The main uses of toluene are as a solvent in Technology Transfer: A Case Study of Petrochemicals in , rubber, and plastic cements and as a feed- Latin America. Baltimore, Md.: The John Hopkins stock in the manufacture of organic chemicals, University Press explosives, detergents, and polyurethane foams. Langley, Roger. 1991. Petrochemicals: An Industry and Xylenes (which exist as three ) are used Its Future. Special Report 2067. London: Economist in the manufacture of DMT, resins, and Intelligence Unit. plasticizers. Naphthalene is mainly used in the National Swedish Environmental Protection Board. manufacture of , pharmaceuticals, insect re- 1987. “Focus on Environmental Impacts of Petro- pellents, and (used in the chemical Plants in Stenungsund. SNV.” Report 3209. manufacture of alkyd resins, plasticizers, and Solna. polyester). UNIDO (United Nations Industrial Development Or- The largest user of phenol in the form of ther- ganization). 1994. “Report on Consultation on mosetting resins is the . Phenol Downstream Petrochemical Industries in Develop- is also used as a solvent and in the manufacture ing Countries in Tehran, Islamic Republic of Iran of intermediates for pesticides, pharmaceuticals, during November 7 through 11, 1993.” Vienna. and dyestuffs. Styrene is used in the manufac- , Her Majesty’s Inspectorate of Pol- ture of synthetic rubber and polystyrene resins. lution. 1993. “Chief Inspector’s Guidance to Inspec- Phthalic anhydride is used in the manufacture tors, Environmental Protection Act 1990. Process of DMT, alkyd resins, and plasticizers such as Guidance Note IPR 4/1: Petrochemical Processes.” phthalates. Maleic anhydride is used in the London: Her Majesty’s Stationery Office. manufacture of and, to some extent, Vergara, Walter, and Dominique Babelon. 1990. The for alkyd resins. Minor uses include the manu- Petrochemical Industry in Developing : A Review facture of malathion and soil conditioners. Ni- of the Current Situation and Prospects for Development trobenzene is used in the manufacture of in the 1990s. World Bank Technical Paper 113. Wash- aniline, benzidine, and dyestuffs and as a sol- ington, D.C.: World Bank. vent in polishes. Aniline is used in the manu- Vergara, Walter, and Donald Brown. 1988. The New Face facture of dyes, including azo dyes, and rubber of the World Petrochemical Sector: Implications for De- chemicals such as vulcanization accelerators and veloping Countries. World Bank Technical Paper 84. antioxidants. Washington, D.C.: World Bank.