STANDARDIZATION METHODS FOR CONTROL

POWER PLANT POLLUTION

BY SREESANKAR .JM.E THERMAL ENGG.

STANDARDIZATION METHODS

1. WORLD BANK STANDARDS

2. OSHA (OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION) STANDARDS

•Choose the cleanest fuel economically available (natural gas is preferable to oil, which is preferable to coal).

•Give preference to high-heat-content, low-ash, low-sulfur coal (or high-heat-content, high sulfur coal, in that order) and consider beneficiation for high-ash, high-sulfur coal.

•Select the best power generation technology for the fuel chosen to balance the environmental and economic benefits

• The choice of technology and pollution control systems will be based on the site-specific environmental assessment.

•Keep in mind that particulates smaller than 10 microns in size are most important from a health perspective. Acceptable levels of particulate matter removal are achievable at relatively low cost.

PRODUCTION AND EMISSIONS CONTROL PRACTICES ACCORDING TO WORLD BANK STANDARDS.

•Note that a comprehensive monitoring and reporting system is required.

•Consider cost-effective technologies such as pre-ESP sorbent injection, along with coal washing, before in-stack removal of sulfur dioxide.

•Use low-NOx burners and other combustion modifications to reduce emissions of nitrogen oxides.

•Before adopting expensive control technologies, consider using offsetting reductions in emissions of critical pollutants at other sources within the air shed to achieve acceptable ambient levels.

•Use SOx removal systems that generate less wastewater, if feasible; however, the environmental and cost characteristics of both inputs and wastes should be assessed case by case.•Manage ash disposal and reclamation so as to minimize environmental impacts especially the migration of toxic metals, if present, to nearby surface and groundwater bodies, in addition to the transport of suspended solids in surface runoff.•Consider reusing ash for building materials.•Consider recirculating cooling systems where thermal discharge to water bodies may be of concern.

OSHA (OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION) STANDARD.

•Rules that describe the methods employers must use to protect employees from hazards.

•Designed to protect workers from a wide range of hazards.

•Limit the amount of hazardous chemicals, substances, or noise that workers can be exposed to

•Require the use of certain safe work practices and equipment

•Require employers to monitor certain hazards and keep records of workplace injuries and illnesses

TYPES OF POLLUTION CONTROL METHODS ADOPTED IN THERMAL POWER PLANTS

AIR POLLUTION CONTROLElectrostatic precipitatorsLow NOX burnersFlue gas stackDry ash extraction

WATER POLLUTION CONTROLCoal/oil setting pitsAsh dykes & disposal systemsAsh water recycling systemEffluent treatment plant

THERMAL POLLUTION CONTROL

NOISE POLLUTION CONTROL

Power Plant Pollution Control

What is beingRemoved byThe electrostaticPrecipitator?

By the wet Scrubber?

POLLUTION CONTROL DEVICES

•The ash left behind after combustion of coal is arrested in high efficiency Electrostatic precipitators(ESP) and particulate emission is controlled well within the stipulated norms.

•The ash collected in the ESP is disposed to ash ponds in slurry form.

•Emission standards(world bank) particulate matter(max)-50 micron per cubic mater.

ELECTROSTATIC PRECIPITATORS (ESP)

DRY ASH EXTRACTION SYSTEM

•Dry ash much higher utilization potential in ash based production. Eg.

1. Land reclamation.2. Structural land filling.3. Road making4. Cement manufacturing.5. Brick manufacturing.

COAL/OIL SETTING PITS.

In these pits, coal dust and oil are removed from the effluents from coal handling plant, coal yard and fuel oil handling areas before discharge into Effluent Treatment Plant (ETP).

ASH DYKES & DISPOSAL SYSTEMS

•Ash ponds are provided for ash disposal.

•Ash ponds are divided into lagoons and provided with garlanding arrangements for changing over of the ash slurry feed points for even filling of the pond and for effective of ash particles•Ash in slurry form is discharged into the lagoons where ash particle settled from the slurry and clear effluent water is discharge from ash ponds.

ASH WATER RECYCLING SYSTEM

•The effluent water from ash pond is circulated back to the power plant for future slucing to the ash pond.

•This helps in saving of fresh water requirement for transportation of ash from the plant.

NEUTRALIZATION PITNeutralization pits are provided in water treatment (WTP) for Ph correction of effluents before discharge into effluent treatment plant (ETP) for future treatment and use.

EFFLUENT TREATMENT PLANT (ETP)

•The objective of industrial liquid effluent treatment plant (ETP) is discharge clean effluent from the power plant to meet environment standards and to reduce intake water requirement.•The schemes involves collection of various effluents and their appropriate treatment centrally and recirculation of treated effluent for various plant uses.

THERMAL POLLUTION

•Cooling towers are provided for cooling the hot condenser cooling water system.

•This helps in reduction in thermal pollution and conservation of fresh water.

•Condensate outlet cooling water (once through) should not be more than 3 degree than intake temperature (World Bank Standard).

•Regenerative feed heating cycle will be used in the process.•Land management

1. Clearing of the existing vegetation will be kept to a minimum and only tothe required extent.

2. Railway siding, water intake facility and water disposal facility will be sorouted that, apart from techno-economic feasibility and other aspects, it will require minimum destruction of vegetation. The roadside plantation will save the existing ecological scenario.

3. Active help from the locals will be solicited in preserving the greenbelt.They will be educated and discouraged destroying the vegetation for fuel purposes etc.

•Green-belt development program will be implemented

THERMAL POLLUTION AND PROPOSED CONTROL MEASURES:

•The entire plant is so procured/installed that resultant noise level within premises remaining with standard limits.

•Standard (World Bank) for industrial area -70dB max outside the project property boundary.

•All the equipment in the power plant will be designed to have a total noise level not exceeding 85-90 dB (A) as per the requirement of OSHA (Occupational Safety and Health Administration) standard.

•Turbines will be housed in closed buildings, which will reduce the noise levels from the turbine generators.

•Earplugs will be provided to the workers, and it should be enforced to be used by workers.

NOISE POLLUTION CONTROL

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