Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum emissions levels that are normally achievable through a combination of cleaner production and end-of-pipe treatment. The guidelines are designed to protect human health; reduce mass loadings to the environment; draw on commercially proven technologies; be cost-effective; follow current regulatory trends; and promote good industrial practices, which offer greater productivity and increased energy efficiency.
Table of Contents
- Industry Description and Practices
- Waste Characteristics
- Pollution Prevention and Control
- Target Pollution Loads
- Treatment Technologies
- Emissions Guidelines
- Monitoring and Reporting
- Key Issues
Industry Description and Practices
Natural gas and crude distillates such as naphtha
from petroleum refining are used as feedstocks
to manufacture a wide variety of
petrochemicals that are in turn used in the manufacture
of consumer goods. The description of
petrochemical processes and products presented
here is for illustrative purposes only. The basic
petrochemicals manufactured by cracking, reforming,
and other processes include olefins
(such as ethylene, propylene, butylenes, and butadiene) and aromatics (such as benzene, toluene, and xylenes). The capacity of naphtha crackers is generally of the order of 250,000–750,000 metric tons per year (tpy) of ethylene production.
Some petrochemical plants also have alcohol and oxo-compound manufacturing units on site. The base petrochemicals or products derived from them, along with other raw materials, are converted to a wide range of products. Among them are:
- Resins and plastics such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene, polystyrene, and polyvinyl chloride (PVC)
- Synthetic fibers such as polyester and acrylic
- Engineering polymers such as acrylonitrile butadiene styrene (ABS)
- Rubbers, including styrene butadiene rubber (SBR) and polybutadiene rubber (PBR)
- Industrial chemicals, including those used for the manufacture of detergents such as linear alkyl benzene (LAB) and of coatings, dyestuffs, agrochemicals, pharmaceuticals, and explosives.
A number of alternative methods for manufacturing the desired products are available. Details on typical processes and products are provided in the Annex.
Fugitive air emissions from pumps, valves, flanges, storage tanks, loading and unloading operations, and wastewater treatment are of greatest concern. Some of the compounds released to air are carcinogenic or toxic. Ethylene and propylene emissions are of concern because their release can lead to the formation of extremely toxic oxides. Compounds considered carcinogenic that may be present in air emissions include benzene, butadiene, 1,2-dichloroethane, and vinyl chloride. A typical naphtha cracker at a petrochemical complex may release annually about 2,500 metric tons of alkenes, such as propylenes and ethylene, in producing 500,000 metric tons of ethylene. Boilers, process heaters, flares, and other process equipment (which in some cases may include catalyst regenerators) are responsible for the emission of particulates, carbon monoxide, nitrogen oxides (200 tpy), based on 500,000 tpy of ethylene capacity, and sulfur oxides (600 tpy).