Optimizing operation to increase recovery boiler throughput

The recovery boiler at the Irving Pulp and Paper Saint John, NB, mill has been through several major retrofits to increase its original firing capacity of 1100 metric tons/day of black liquor dry solids to the present level of 1680 metric tons/day. Many problems have been encountered over the years, including tube corrosion and cracking, as well as plugging of flue gas passages, but they all have been overcome through operational changes and process optimization. The latest challenge is to increase throughput without experiencing high total reduced sulfur (TRS) levels that would impact the environment and jeopardize compliance. An optimization program has been in place at the mill since December 2008 to further increase boiler production while maintaining environmental performance. The program, which automates liquor addition at full capacity according to targeted stack gas O2 and TRS levels, enables the boiler to operate at lower stack gas O2 targets and to achieve a 2%-3% increase in liquor throughput, while keeping TRS emissions under compliance.

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Improving recovery boiler availability through understanding fume behavior

TAPPI Journal ◽

10.32964/tj15.3.187 ◽

2016 ◽

Vol 15 (3) ◽

pp. 187-193 ◽

Cited By ~ 2

Author(s):

AINO LEPPÄNEN ◽

ERKKI VÄLIMÄKI

Keyword(s):

Flow Field ◽

Alkali Metal ◽

Flue Gas ◽

Inorganic Compounds ◽

Black Liquor ◽

Computational Method ◽

Metal Vapors ◽

Recovery Boilers ◽

Recovery Boiler ◽

Elemental Release

Unexpected recovery boiler shutdowns are rare, but they can cost millions of dollars in lost income. Sometimes the inorganic compounds in black liquor can cause sudden fouling or plugging problems that could not be predicted beforehand. The ash particles can be divided into two main types and size classes: carryover and fume. This paper focuses on the smaller fume particles that form through the condensation of alkali metal vapors and that deposit via different mechanisms than carryover. The location of fume deposition depends on several factors, such as flue gas and superheater temperatures, black liquor composition, and the flow field in the boiler. This paper presents results obtained with a computational method that simulates fume formation in recovery boilers. The paper focuses on the effect of black liquor composition and elemental release on fume behavior and suggests how these observations should be taken into account when designing new boilers or retrofits. Moreover, the paper introduces the possible applications of the modeling method. These include, for example, troubleshooting of fouling problems in existing boilers, designing superheater configurations for new boilers, and positioning soot blowers.

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Techno-Economic Evaluation of Co-Removal of NOx and SOx Species from Flue Gases via Enhanced Oxidation of NO by ClO2—Case Studies of Implementation at a Pulp and Paper Mill, Waste-to-Heat Plant and a Cruise Ship

Energies ◽

10.3390/en14248512 ◽

2021 ◽

Vol 14 (24) ◽

pp. 8512

Author(s):

Jakob Johansson ◽

Fredrik Normann ◽

Klas Andersson

Keyword(s):

Flue Gas ◽

Cost Estimation ◽

Paper Mill ◽

Pulp And Paper ◽

Flue Gases ◽

Cruise Ship ◽

Pulp And Paper Mill ◽

Enhanced Oxidation ◽

Recovery Boiler ◽

Oxidation Of No

Co-absorption of NO2 and SO2 from flue gases, in combination with the enhanced oxidation of NO by ClO2(g), is studied for three different flue gas sources: a medium sized waste-to-heat plant; the kraft recovery boiler of a pulp and paper mill; and a cruise ship. Process modeling results are used to present the technical potential for each site together with cost estimation and optimization using a bottom-up approach. A process set-up is proposed for each site together with equipment sizing and resulting flows of process fluids. The simulation results, supported by experimental results, show that removal rates equal to or greater than current best available technologies are achievable with more than 90% of NOx and 99% of SO2 removed from the flue gas. The resulting cost of removing both NOx and SO2 from the flue gases is 2100 €/ton for the waste-to-heat plant, 800 €/ton for the cruise ship and 3900 €/ton for the recovery boiler. The cost estimation show that the consumption and cost of chemical additives will play a decisive role in the economic feasibility of the investigated concept, between 50% and 90% of the total cost per ton acid gas removed.

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Could biomass-fueled boilers be operated at higher steam temperatures? Part 3: Initial analysis of costs and benefits

TAPPI Journal ◽

10.32964/tj13.8.65 ◽

2014 ◽

Vol 13 (8) ◽

pp. 65-78 ◽

Cited By ~ 3

Author(s):

W.B.A. (SANDY) SHARP ◽

W.J. JIM FREDERICK ◽

JAMES R. KEISER ◽

DOUGLAS L. SINGBEIL

Keyword(s):

Flue Gas ◽

Power Plants ◽

Superheated Steam ◽

Black Liquor ◽

Simulation Software ◽

Operating Conditions ◽

Costs And Benefits ◽

Steam Generation ◽

Fireside Corrosion ◽

Corrosion Resistant

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.

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Modeling fine particles and alkali metal compound behavior in a kraft recovery boiler

TAPPI Journal ◽

10.32964/tj11.7.9 ◽

2012 ◽

Vol 11 (7) ◽

pp. 9-14 ◽

Cited By ~ 2

Author(s):

AINO LEPPÄNEN ◽

ERKKI VÄLIMÄKI ◽

ANTTI OKSANEN

Keyword(s):

Alkali Metal ◽

Computational Models ◽

Fine Particles ◽

Black Liquor ◽

Melting Behavior ◽

Metal Compound ◽

Effect Of Temperature ◽

Particle Model ◽

Boiler Furnace ◽

Recovery Boiler

Under certain conditions, ash in black liquor forms a locally corrosive environment in a kraft recovery boiler. The ash also might cause efficiency losses and even boiler shutdown because of plugging of the flue gas passages. The most troublesome compounds in a fuel such as black liquor are potassium and chlorine because they change the melting behavior of the ash. Fouling and corrosion of the kraft recovery boiler have been researched extensively, but few computational models have been developed to deal with the subject. This report describes a computational fluid dynamics-based method for modeling the reactions between alkali metal compounds and for the formation of fine fume particles in a kraft recovery boiler furnace. The modeling method is developed from ANSYS/FLUENT software and its Fine Particle Model extension. We used the method to examine gaseous alkali metal compound and fine fume particle distributions in a kraft recovery boiler furnace. The effect of temperature and the boiler design on these variables, for example, can be predicted with the model. We also present some preliminary results obtained with the model. When the model is developed further, it can be extended to the superheater area of the kraft recovery boiler. This will give new insight into the variables that increase or decrease fouling and corrosion

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EXERGETIC ANALYSIS OF A CHEMICAL RECOVERY BOILER IN THE PULP AND PAPER INDUSTRY

10.26678/abcm.encit2020.cit20-0342 ◽

2020 ◽

Author(s):

Magno Salgado ◽

Vinícius Trindade ◽

Rogério José Silva

Keyword(s):

Paper Industry ◽

Pulp And Paper Industry ◽

Pulp And Paper ◽

Chemical Recovery ◽

Recovery Boiler ◽

Exergetic Analysis

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Biosludge Incineration in a Recovery Boiler

Water Science & Technology ◽

10.2166/wst.1999.0712 ◽

1999 ◽

Vol 40 (11-12) ◽

pp. 195-200 ◽

Cited By ~ 6

Author(s):

P. Harila ◽

V.-A. Kivilinna

Keyword(s):

Black Liquor ◽

Pulp Mill ◽

Effluent Treatment ◽

Attractive Alternative ◽

Net Energy ◽

High Moisture ◽

Primary Sludge ◽

Start Up ◽

Combustion Emissions ◽

Recovery Boiler

An activated sludge process is an effective tool against effluent emissions in a pulp mill. It has only a few features which can be regarded deficiences. One of them is that effluent treatment of a modern pulp mill creates some 10-20 tonnes dry solids of biosludge per day. This sludge is difficult to burn due to its high moisture content. The most common way is to mix biosludge with primary sludge, to dewater the mixture in presses and finally to burn it in a solid fuel boiler. This type of sludge treatment incurs rather high costs and does not produce any net energy. Also combustion emissions vary depending on the boiler type. The Metsä-Botnia Kemi Pulp Mill was the first mill in the world to burn biosludge in a recovery boiler. The system start-up was in 1993 and it has been in operation ever since. Mechanically dewatered biosludge is mixed with weak black liquor and concentrated in a conventional evaporation plant equipped with a pressurized superconcentrator unit. In a modern recovery boiler, firing conditions are well controlled and monitored. Better emission control than in most bark fired boilers is achieved. Accumulation of nonprocess elements, corrosion, plugging, scaling and some other operational problems were expected. A lot of experience has been gathered during the years of operation and reviewed in this presentation. The achieved benefits of the system are discussed. Disposal of biosludge in a recovery boiler offers an economically and environmentally attractive alternative. Probably the best evidence from this is the fact that Metsä-Botnia has applied the same process solution in the recent reconstruction of the recovery departments at the Jouteno Mill.

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The Market Valuation of Environmental Capital Expenditures by Pulp and Paper Companies

The Accounting Review ◽

10.2308/accr.2004.79.2.329 ◽

2004 ◽

Vol 79 (2) ◽

pp. 329-353 ◽

Cited By ~ 233

Author(s):

Peter M. Clarkson ◽

Yue Li ◽

Gordon D. Richardson

Keyword(s):

Environmental Performance ◽

Capital Expenditure ◽

Paper Industry ◽

Pulp And Paper Industry ◽

Economic Benefits ◽

Pulp And Paper ◽

Market Valuation ◽

The Future ◽

Environmental Capital ◽

Polluting Firms

The objective of this study is to examine the market valuation of environmental capital expenditure investment related to pollution abatement in the pulp and paper industry. The total environmental capital expenditure of $8.7 billion by our sample firms during 1989–2000 supports the focus on this industry. In order to be capitalized, an asset should be associated with future economic benefits. The existing environmental literature suggests that investors condition their evaluation of the future economic benefits arising from environmental capital expenditure on an assessment of the firms' environmental performance. This literature predicts the emergence of two environmental stereotypes: low-polluting firms that overcomply with existing environmental regulations, and high-polluting firms that just meet minimal environmental requirements. Our valuation evidence indicates that there are incremental economic benefits associated with environmental capital expenditure investment by low-polluting firms but not high-polluting firms. We also find that investors use environmental performance information to assess unbooked environmental liabilities, which we interpret to represent the future abatement spending obligations of high-polluting firms in the pulp and paper industry. We estimate average unbooked liabilities of $560 million for high-polluting firms, or 16.6 percent of market capitalization.

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