Equipment for Cooling Tower, Boiler Blowdown, and FGD Purge Streams to Optimize Water Use
The power generation industry is the most water-intensive industry in North America. The droughts that some US states have faced present critical challenges for this industry. Facilities must now consider ways of lowering water consumption while ensuring that wastewater meets EPA regulations. This market insight discusses the strategies power plants can implement to limit freshwater use. It also highlights key treatment technologies for both water and wastewater. Topics also include specific case studies of projects in the United States and various logistical challenges. The base year is 2012.
Water and Wastewater Management in Power Generation
Objectives of this Research Service
- Assess the current and future water management, consumption, and treatment required for power generation.
- Identify the potential trends for future power generation activities and cleaner wastewater effluent.
- Identify strategies and future treatment solutions required for water treatment companies in North America.
- Understand and identify opportunities for all suppliers in the value chain; to help develop economic growth; and to meet and exceed the North American environmental regulations associated with water and wastewater treatment and management.
- Addressable Industry Challenge: The power industry is deemed to be one of the most water intensive industries for water, wastewater consumption, and wastewater treatment. What are the market strategies to comply with regulations, address water scarcity, and face permit issues?
- Power Generation Industry: What are the best practices in place (water reuse and recycling or innovative treatment processes) to help treat difficult wastewater produced and to lower water used in cooling tower blowdown treatment and as boiler feedwater condensate polishing as well as to lower the wastewater produced by flue gas desulfurization?
- Components: What treatment technologies are needed to help lower water consumption? What are the multiplier effects on the industry from capital cost savings through saved time and labor?
Overview of the Water and Wastewater Treatment Strategies in the Power Generation Industry
The Challenge in the Industry
The power generation industry is the largest water-consuming industry in North America. Certain states across the United States have been suffering from drought over the last few years, and water scarcity is increasing. Power generation plants must comply with increasingly stringent US Environmental Protection Agency (US EPA) pollution guidelines for discharge permits. Investing capital is a challenge because companies must find the best recycle and reuse solutions at the most economical price. Providing plants with operational water and industrial wastewater treatment services will address the growing concern of operational and labor risks.
Potential Facility Savings
Facilities can provide operational water and wastewater services to help combat operational cost inefficiencies. Statewide, lowering freshwater consumption in drought-stricken states will help maintain a sustainable price for water. Closed-loop systems treat and recapture water, which can be reused in the boiler or cooling tower to help reduce operating costs. Furthermore, existing treatment systems need to be upgraded to newer, more efficient systems.
Targeted Areas to Consider
Using natural gas in combustion turbines consumes less water and does not produce as much water discharge as coal plants using steam turbines. Facilities should consider using more combustion turbines. Cooling tower blowdown, boiler blowdown, flue gas desulfurization (FGD) purge streams, and feedwater are areas to target to reduce consumption. Power plants need to consider the types of investments they are making. Significant cost savings can be achieved based on the fossil fuel used, which can significantly save in capital investments on equipment systems, treatment of water and wastewater, and facility maintenance.
- The power generation industry produces energy or electricity using different types of fossil fuels or renewable fuels. A power plant may have more than one generator, and each generator may use a different fuel.
- This study covers power plants using coal, natural gas, fuel oil, and nuclear fuel. Renewable energy, such as wind and hydroelectric power, are not included in this study.
- The power market coverage consists of facilities that are privately-owned or government-owned electric power stations and that have at least a $X million in total investment value.
- The water and wastewater treatment solutions used in the power industry include the following:
- Membrane equipment: Ultrafiltration, microfiltration, reverse osmosis.
- Electrodeionization (EDI) or ion exchange.
- Disinfection (biocides, UV*, ozonation, electrochlorination).
- Physical or chemical separation: Ultrafiltration, microfiltration, reverse osmosis.
- Zero liquid discharge (ZLD) systems.
- Thermal evaporators (FGD blowdown).
Boilers used in thermal recovery processes typically produce steam with a quality of about X% water recovery. This results in X% of the boiler feedwater not being vaporized. The separated water stream that leaves the boiler is called blowdown and has high concentrations of total dissolved solids (TDSs). These concentrations are X to X times more than what is in the boiler feedwater.
Cooling Tower Blowdown
Blowdown contains TDSs that, over time, become concentrated and form scale. Scale inhibitors are added to cooling water to help keep its solubility levels high. Cooling towers suffer from corrosion, scale build-up, and bacterial growth. The water is treated with scale corrosion and biocide inhibitors or some form of disinfection control. The high levels of TDSs and biocides in cooling tower blowdown create environmental issues when wastewater is discharged into the public sewers.
Flue gas desulfurization technology is comprised of wet or dry scrubbers and is used commonly in North American power plants that use coal. Dry scrubbers use limestone as a reagent for sulfur dioxide removal and produce less wastewater compared to wet scrubbers.
Power plants in the United States use wet scrubbers when sulfur content is higher than X%. Wet scrubbers produce a purge stream that needs to be removed for optimal scrubber performance. The purge stream contains contaminants such as TDSs, heavy metals, total suspended solids (TSSs), organic compounds, and salts. All of these contaminants require treatment.
Engineering, Procurement, and Construction (EPC)
EPC firms are essential for both retrofit projects and new building projects. These firms work with original equipment manufacturers (OEMs) and end users to design, construct, and procure all materials and equipment, and to build per the project requirements.
Design engineering firms are contracted to do initial front-end engineering design work, which is later sent to vendors that propose bids. EPC firms can also undertake front-end design work, depending on the project.
TDS—Total dissolved solids are a combination of organic and inorganic compounds (including nitrates, calcium, sodium, and phosphates) found in water and wastewater.
Biocides and Inhibitors
These are chemicals used in the water and wastewater industry as anti-scalents to prevent fouling inside the towers. The use of these chemicals enhances heat transfer in the process for electricity generation and reduces cleaning and regular maintenance. These chemicals are also used to disinfect water to prevent any microbial growth.
Integrated Gasification Combined Cycle—This technology uses a gasifier to convert coal and other hydrocarbon fuels into synthesis gas (syngas). After the conversion, it removes any contaminants from the syngas before the syngas is combusted in a turbine. This technology is typically used instead of a steam turbine as it requires less water.
Total suspended solids (TSSs) are particles that are suspended in water and will not pass through filters. The presence of TSSs allows for a measurement of the turbidity of water as the contaminants do not settle and separate in the water. Some form of treatment is required; otherwise, TSSs can block filter medias and reduce their effectiveness.
Table of Contents
Executive Summary 5 Definitions 7 Introduction and Overview 11 Regulations 22 Treatment Technology and Market Landscape 25 Case Studies 31 Conclusion 37 Appendix 40 The Frost & Sullivan Story 42
To order this report: North America Industrial Wastewater Series—Power Generation Industry http://www.reportlinker.com/p01658933-summary/North-America-Industrial-Wastewater-Series-Power-Generation-Industry.html