Preliminary Estimates of Performance and Cost of Mercury Control Technology Applications on Electric Utility Boilers

ABSTRACT

Under the Clean Air Act Amendments of 1990, the U.S. Environmental Protection Agency (EPA) determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powdered activated carbon (PAC) injection-based mercury control technologies were developed. This paper presents these estimates and develops projections of costs for future applications.

Cost estimates were developed using PAC to achieve a minimum of 80% mercury removal at plants using electrostatic precipitators and a minimum of 90% removal at plants using fabric filters. These estimates ranged from 0.305 to 3.783 mills/kWh. However, the higher costs were associated with a minority of plants using hot-side electrostatic precipitators (HESPs). If these costs are excluded, the estimates range from 0.305 to 1.915 mills/kWh. Cost projections developed using a composite lime-PAC sorbent for mercury removal ranged from 0.183 to 2.270 mills/kWh, with the higher costs being associated with a minority of plants that used HESPs.     

Government/Industry Cost Sharing for Air Pollution Control

Several existing federal and state provisions act to reduce the cost to in dustry of controlling air pollution. Included are the federal corporate income tax, depreciation allowances, investment credits, small Business Administration loans, Economic Development Administration aid, and state tax laws. These provisions give government assistance to industry amounting to as much as 59 percent of the cost of air pollution control. Numerous bills have been introduced in Congress that would give additional government aid to industry in the form of special across-the-board tax allowances for air pollution control equipment. A typical bill of this type would result in the government bearing an additional 11 percent of these costs. There are several possible objectives for this kind of additional aid; however, none of these seem valid when the amount of present assistance is recognized. From this analysis, it would seem that additional across-the-board tax subsidies for air pollution control equipment are neither required nor advisable. Future studies and/or experience may show certain firms or industries for which air pollution control will be too great a burden and for which additional government assistance is advisable. When such cases are found, legislation should be enacted only after the pros and cons of the various assistance methods are considered.     

Performance and Cost Comparisons between Fabric Filters and Alternate Participate Control Techniques

A study was conducted to evaluate performance and cost comparisons of fabric filters and alternate fine particulate control techniques. In relating the removal of fine particulate to costs, due to the lack of fractional efficiency data, it was found necessary to treat a specific application in order to make the study manageable. The case chosen is that of the coal fired industrial boiler since Enviro-Systems has a pilot program in this application area.     

Technology Innovations and Experience Curves for Nitrogen Oxides Control Technologies

Abstract

This paper reviews the regulatory history for nitrogen oxides (NO_x) pollutant emissions from stationary sources, primarily in coal-fired power plants. Nitrogen dioxide (NO₂) is one of the six criteria pollutants regulated by the 1970 Clean Air Act where National Ambient Air Quality Standards were established to protect public health and welfare. We use patent data to show that in the cases of Japan, Germany, and the United States, innovations in NO_x control technologies did not occur until stringent government regulations were in place, thus “forcing” innovation. We also demonstrate that reductions in the capital and operation and maintenance (O&M) costs of new generations of high-efficiency NO_x control technologies, selective catalytic reduction (SCR), are consistently associated with the increasing adoption of the control technology: the so-called learning-by-doing phenomena. The results show that as cumulative world coal-fired SCR capacity doubles, capital costs decline to ~86% and O&M costs to 58% of their original values. The observed changes in SCR technology reflect the impact of technological advance as well as other factors, such as market competition and economies of scale.     

An Evaluation of Emissions and Control Technologies for the Metal Decorating Process

Data are reported on a number of controlled and uncontrolled sources from various metal decorating operations. Emission levels are related to process variables such as ink coverage, coater speed, sheet size, and applied coating film weight. Results are presented depicting variation of organic emission levels from a coating process line with elapsed process time. For controlled sources employing either catalytic or thermal incineration, conversion efficiencies are reported as a function of temperature. Operational curves are presented for each control system studied indicating the dependence of carbon dioxide, NO_x, and organic output on incineration temperatures.     

An Evaluation of Emissions and Control Technologies for the Metal Decorating Process

A simple but effective sampling and analytical procedure is described for determining total organics, carbon dioxide, carbon monoxide, and methane emitted from web offset printing presses. Data are reported on a number of controlled and uncontrolled sources and emission levels are related to process variables such as press speed, ink coverage and dryer type. For controlled sources employing either catalytic or thermal incineration units, conversion efficiencies are reported as a function of temperature. Operational curves are presented for each control system studied indicating the dependency of carbon dioxide, NO_xt and organic output to incineration temperatures.     

The Cost Estimation of Thermal and Catalytic Incinerators for the Control of VOCs

In an earlier paper, major commercially available incinerator technologies designed to treat dilute waste gas streams containing volatile organic compounds (VOCs) were described in a qualitative comparison. In addition, a simplified procedure was outlined through which important sizing parameters could be calculated given certain information about the waste gas. This paper describes the use of these parameters in developing a study (±30percent) cost estimate for the total capital investment and the total annual costs incurred in treating a waste stream of volatile organic compounds (VOCs). An illustrative problem used in the former paper is completed here in order to contrast some of the economic differences between thermal and catalytic incinerator systems.     

Net Waste Reduction Analysis Applied to Air Pollution Control Technologies

Post-combustion air pollution control technologies were evaluated to determine total waste produced by the operation of these systems. A continuum of air pollution control technology choices providing increasing levels of control is presented and the quantity of waste produced by each air pollution control option has been calculated. In addition, this analysis accounts for waste produced indirectly by the generation of energy required for operation of the control technologies. This type of analysis can be used to select optimal control levels and to demonstrate why a goal of zero air emissions may not be environmentally desirable.     

Estimates for pollution profiles above finite area-sources

A theoretical basis is presented for an integral-equation method of describing airborne pollution concentrations above an arbitrary area-source and for arbitrary air-surface exchange. The method is then used to describe concentrations of pesticides above a treated field, and the predicted profiles are used to interpret recently reported data. For this case, different profiles can result from different fetch-dependent source strengths, in turn dictated by each pesticide's air/surface partition coefficient.     

Plume Rise Estimates for Electric Generating Stations

The Tennessee Valley Authority, under sponsorship of the Public Health Service, National Air Pollution Control Administration, initiated a comprehensive study entitled “Full-Scale Study of Plume Rise at Large Electric Generating Stations” in 1963. The variability of plant sizes, stack heights, and stack configurations accommodated full-scale assessment of plume rise over a wide range of meteorological and operational conditions.     

农村水环境的生态治理模式与技术探讨

从农村的自然生态环境和农业生产的需要出发,分析了农村水污染源的资源性特点,指出了农村水污染的实质是富余肥料资源大量流失到水体,而不是被农作物等吸收利用,从而建立了源头控制、过程生态处理利用、终端生态修复的农村水环境生态治理模式,并分析了相关技术要点。     

切圆燃烧煤粉炉的空气分级燃烧改造

阐述了分级燃烧抑制NOx形成的基本原理,介绍了切圆燃烧煤粉炉的空气分级燃烧改造的基本特点,考察了轴向和径向空气分级、炉内空气浓度等因素对NOx排放量的影响;控制适当条件,使脱氮效率达到30％－50％,对煤粉炉的空气分级燃烧改造进行了费用效益分析。     

Assessment of Dry Sorbenf Emission Control Technologies Part II. Applications

The injection of dry alkaline compounds into the furnace or post-furnace regions of utility boilers to reduce SO₂ is currently under development as a lower cost option to conventional flue gas desulfurization technology. Part I of this paper focused on the science and process development of the various dry sorbent technologies. Part II will address applications of these technologies, including SO₂ removals in full-scale boilers, methodologies for designing sorbent injection systems, power plant impacts, process integration issues, and cost.

Because the dry technologies use the furnace and/or ducts as the chemical contactor, potential impacts on power plant operation and reliability are as critical in assessing the commercial applicability of each technology as SO₂ removal and sorbent utilization. Consequently, the technical and economic feasibility of the various dry processes is highly site specific.     

Control Technologies for Remediation of Contaminated Soil and Waste Deposits at Superf und Lead Battery Recycling Sites

This paper primarily addresses remediation of contaminated soils and waste deposits at defunct lead-acid battery recycling sites (LBRS) via immobilization and separation processes. A defunct LBRS is a facility at which battery breaking, secondary lead smelting, or both operations were performed for the primary purpose of reclaiming lead from spent lead-acid batteries. Metallic lead and lead compounds are generally the principal contaminants of concern in soils and waste deposits (i.e., buried, piled, landfilled waste) at these sites. Other metals (e.g., cadmium, copper, arsenic, antimony, and selenium) are often present at LBRS, but usually at much lower concentrations than lead and often present below hazardous concentrations. This article is primarily based on experience gained from: (1) Superfund site investigation, removal, and remedial actions, and (2) development and demonstration of control technologies under the Superfund Innovative Technology Evaluation (SITE) Program. The primary remedial options for lead contaminated soils and waste deposits include: (1) no action, (2) off-site disposal, (3) containment, (4) immobilization, (5) separation with resource recovery, and (6) separation without resource recovery. In spite of the toxicity of lead at low concentrations, the relative immobility of lead and site-specific risk assessments can still result in the selection of no action or containment remedies. Solidification/stabilization of lead-contaminated soils has been implemented at three Superfund sites and is the selected remedy at several others. Separation technologies (e.g., screening, extraction) are attractive because, if successful, they actually remove the contaminant from the environmental media. Separation technologies also offer the possibility that a valuable product (e.g., lead, plastic, energy) can be recovered, but careful consideration of economic and technical factors are required. Compared to the implementation of containment and solidification I stabilization remedies, separation technologies tend to be relatively novel, complex, and costly.     

Assessment of Dry Sorbent Emission Control Technologies Part I. Fundamental Processes

The utility and industrial sectors continue to come under pressure from both national and local regulatory groups to reduce sulfur dioxide emissions. With a trend in the utility industry for life extension, retrofit technologies are likely to play an important role in any SO₂ emission reduction strategy. Potential retrofit technologies include, singly and in combination: coal switching or cleaning, wet or dry FGD, conversion to fluidized bed, and dry sorbent injection. The diversity within the utility industry in terms of unit size, unit age, fuel use, financial base, and geographic location dictates the need for a variety of technologies to address SO₂ emission control. Dry injection processes involving the injection of dry powders into either the furnace or post-furnace region offer the potential for low capital cost retrofitable technologies. However, compared to wet FGD processes, the dry calcium based processes will likely have lower SO₂ removal efficiencies and may pose more plant-wide integration issues that need to be addressed from both an applications and R&D perspective.

This paper provides a critical assessment of dry injection technologies, in two parts. Part 1 focuses on sorbent processes and science. An assessment of the different dry sorbent processes and the effect of process parameters is provided. Emphasis is placed on process limitations and potential avenues to enhance SO₂ removal. Part 2 will deal with applications of the technology, addressing cost, scale-up, and integration issues.

Much of the data included in this paper was presented at the 1986 Joint Symposium on Dry SO₂ and Simultaneous SO₂/NO_x Control Technologies, sponsored by the Electric Power Research Institute and the Environmental Protection Agency and held in June 1986. This paper provides both an overview and an evaluation of the technology, based largely on our analysis of the data and interpretations discussed at this symposium.     

Predicting the Performance of Particulate Control Equipment

A new probabilistic modeling environment is described which allows the explicit and quantitative representation of the uncertainties inherent in new environmental control processes for SO₂ and NO_x removal. Stochastic analyses provide additional insights into the uncertainties in process performance and cost not possible with conventional deterministic or sensitivity analysis. Applications of the probabilistic modeling framework are illustrated via an analysis of the performance and cost of the fluidized bed copper oxide process, an advanced technology for the control of SO₂ and NO_x emissions from coal-fired power plants. An engineering model of a conceptual commercial-scale system provides the basis for the analysis. The model also captures interactions between the power plant, the SO₂/NO_x removal process, and other components of the emission control system. Results of the analysis address payoffs from process design improvements; the dependence of system cost on process design conditions and the availability of byproduct markets; and the likelihood that the advanced process will yield cost savings relative to conventional technology. The implications of case study results for research planning and comparisons with alternative systems also are briefly discussed.     

Technologies for deodorization of malodorous gases

There is an increasing number of citizens’ complaints about odor nuisance due to production or service activity. High social awareness imposes pressure on entrepreneurs and service providers forcing them to undertake effective steps aimed at minimization of the effects of their activity, also with respect to emission of malodorous substances. The article presents information about various technologies used for gas deodorization. Known solutions can be included into two groups: technologies offering prevention of emissions, and methodological solutions that enable removal of malodorous substances from the stream of emitted gases. It is obvious that the selection of deodorization technologies is conditioned by many factors, and it should be preceded by an in-depth analysis of possibilities and limitations offered by various solutions. The aim of the article is presentation of the available gas deodorization technologies as to facilitate the potential investors with selection of the method of malodorous gases emission limitation, suitable for particular conditions.