scholarly journals De‐bottlenecking a pulp mill by producing biofuels from black liquor in 3 steps

ChemSusChem ◽  
2021 ◽  
Author(s):  
Joseph Samec ◽  
Davide Di Francesco ◽  
Christian Dahlstrand ◽  
Joakim Löfstedt ◽  
Alexander Orebom ◽  
...  
Keyword(s):  
Black Liquor ◽  
Pulp Mill

Biorefinery implementation for recovery debottlenecking at existing pulp mills- Part II: Techno-economic evaluation

TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 17-24 ◽  
Author(s):  
HAKIM GHEZZAZ ◽  
LUC PELLETIER ◽  
PAUL R. STUART
Keyword(s):  
Cost Estimation ◽  
Process Model ◽  
Black Liquor ◽  
Pulp Mill ◽  
Value Added ◽  
Economic Assessment ◽  
Extraction Process ◽  
Estimation Methods ◽  
Precipitation Process

The evaluation and process risk assessment of (a) lignin precipitation from black liquor, and (b) the near-neutral hemicellulose pre-extraction for recovery boiler debottlenecking in an existing pulp mill is presented in Part I of this paper, which was published in the July 2012 issue of TAPPI Journal. In Part II, the economic assessment of the two biorefinery process options is presented and interpreted. A mill process model was developed using WinGEMS software and used for calculating the mass and energy balances. Investment costs, operating costs, and profitability of the two biorefinery options have been calculated using standard cost estimation methods. The results show that the two biorefinery options are profitable for the case study mill and effective at process debottlenecking. The after-tax internal rate of return (IRR) of the lignin precipitation process option was estimated to be 95%, while that of the hemicellulose pre-extraction process option was 28%. Sensitivity analysis showed that the after tax-IRR of the lignin precipitation process remains higher than that of the hemicellulose pre-extraction process option, for all changes in the selected sensitivity parameters. If we consider the after-tax IRR, as well as capital cost, as selection criteria, the results show that for the case study mill, the lignin precipitation process is more promising than the near-neutral hemicellulose pre-extraction process. However, the comparison between the two biorefinery options should include long-term evaluation criteria. The potential of high value-added products that could be produced from lignin in the case of the lignin precipitation process, or from ethanol and acetic acid in the case of the hemicellulose pre-extraction process, should also be considered in the selection of the most promising process option.

Managing total reduced sulfur emissions at a Canadian kraft pulp mill

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 265-272 ◽  
Author(s):  
ROHAN BANDEKAR ◽  
JIM FREDERICK ◽  
JAROSLAV STAVIK
Keyword(s):  
Direct Contact ◽  
Black Liquor ◽  
Pulp Mill ◽  
Packed Bed ◽  
Average Value ◽  
Emission Limit ◽  
Total Reduced Sulfur ◽  
Reduced Sulfur ◽  
Air Ingress ◽  
Solids Content

This study addresses the challenges a dissolving-grade pulp mill in Canada faced in 2014 in meeting its total reduced sulfur (TRS) gas emission limit. These emissions from the recovery boiler exit are controlled by passing the boiler exit gas through a TRS scrubber system. The mill employs a cyclonic direct contact evaporator to concentrate black liquor to firing solids content. The off-gases from the direct contact evaporator flow to the effluent gas control system that consists of a venturi scrubber, a packed bed scrubber, and a heat recovery unit. Emissions of TRS greater than the regulated limit of 15 ppm were observed for a 4-month period in 2014. The level of emissions measured during this period was significantly higher than about 12 ppm, the expected average value based on historic experience. The problem persisted from mid-June 2014 until the annual mill shutdown in October 2014. The main TRS components detected and the performance of the Teller scrubber in capturing them are examined. Other potential causes for these emissions are identified, including mechanical problems such as broken packing in the TRS packed bed scrubber, broken baffle plates in the scrubber, and cyclone evaporator leaks causing air ingress. Repairs were carried out during the mill shutdown, which eliminated the TRS emissions problem.

Commissioning brownstock washing controls for an evaporator limited mill

TAPPI Journal ◽  
2016 ◽  
Vol 15 (7) ◽  
pp. 459-464
Author(s):  
RICARDO SANTOS ◽  
PETER HART
Keyword(s):  
Control System ◽  
Negative Impact ◽  
Black Liquor ◽  
Pulp Mill ◽  
Control Program ◽  
Separation Point ◽  
Water Control ◽  
Oxygen Delignification ◽  
Percentage Points

An automated shower water control system has been implemented to reduce the volume and variability of weak black liquor being sent from the pulp mill to the evaporators. The washing controls attempt to balance the need for consistent and low soda carryover to the bleach plant with consistently high weak black liquor solids being sent to the evaporators. The washer controls were implemented on two bleachable grade hardwood lines (one with oxygen delignification, one without oxygen delignification) and one pine line. Implementation of the control program resulted in an increase in black liquor solids of 0.6 percentage points for the hardwood lines. Significant foam reduction was realized on the pine line since the pine black liquor solids were able to be consistently maintained just below the soap separation point. Low black liquor solids excursions to the evaporators were eliminated. Bleach plant carryover was stabilized and no negative impact on chemical consumption was noticed when controlling weak black liquor solids to recovery.

Biosludge Incineration in a Recovery Boiler

1999 ◽  
Vol 40 (11-12) ◽  
pp. 195-200 ◽  
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.

Purification of pulp mill condensates by an adsorptive process on activated carbon

Holzforschung ◽  
2019 ◽  
Vol 73 (6) ◽  
pp. 589-597 ◽  
Author(s):  
José A.F. Gamelas ◽  
Sofia M. Rebola ◽  
Margarita G. Evtyugina ◽  
Valdemar I. Esteves ◽  
Dmitry V. Evtuguin
Keyword(s):  
Activated Carbon ◽  
Volatile Compounds ◽  
Water Cycle ◽  
Black Liquor ◽  
Pulp Mill ◽  
Dimethyl Disulfide ◽  
Pulp Mills ◽  
Wide Range ◽  
New Process ◽  
Pseudo Second Order

Abstract In order to close the water cycle in pulp mills with condensates instead of fresh water, the malodorous/hazardous volatile compounds and colored substances have to be removed by appropriate efficient methods. In the present work, the condensate from the evaporation of black liquor (BL) from a kraft mill was purified by a batch adsorptive process by means of commercial activated carbon (AC). The effluent was found to contain a wide range of aromatic and organosulfur volatile compounds, including toluene, ethylguaicol, syringaldehyde, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), 2,3-dimethylthiophene, benzothiol and benzothiophene derivatives. Methanol was the major volatile organic component in the condensate (201 mg l−1), which was, however, poorly adsorbed on the AC surface. Aromatics and organosulfur contaminants were adsorbed almost completely in 2–5 min at 23°C under the optimized AC load (900 mg l−1). The treatment allowed the elimination of up to 99% of the obnoxious odor, color and turbidity of the condensate. The adsorption equilibrium followed the Langmuir model and the pseudo-second-order kinetics. The new process could be incorporated in the pulp mill with relatively low additional reagent costs.

scholarly journals Nesterenkonia alba sp. nov., an alkaliphilic actinobacterium isolated from the black liquor treatment system of a cotton pulp mill

2009 ◽  
Vol 59 (4) ◽  
pp. 863-868 ◽  
Author(s):  
H.-Y. Luo ◽  
Y.-R. Wang ◽  
L.-H. Miao ◽  
P.-L. Yang ◽  
P.-J. Shi ◽  
...  
Keyword(s):  
Black Liquor ◽  
Pulp Mill ◽  
Treatment System

Review of Some Data on Corrosion of Stainless Steel and Higher Alloys in Pulp Mill Equipment

CORROSION ◽  
1961 ◽  
Vol 17 (6) ◽  
pp. 9-13
Author(s):  
Harold C. Templeton
Keyword(s):  
Carbon Steel ◽  
Black Liquor ◽  
Pulp Mill ◽  
High Strength ◽  
Case Histories ◽  
Good Resistance ◽  
Green Liquor ◽  
Corrosion Rates ◽  
Alkaline Pulping ◽  
Mill Equipment

Abstract Allowable corrosion rates for equipment with low corrosion tolerance are discussed. Corrosion case histories in the various pulping processes are presented. Sulfite pulping solutions are most frequently-handled in 316 material. Stainless 316 is used because of good resistance to local attack under scale or deposits. In alkaline pulping, soda process digesters are usually made of carbon steel with heater tubing of either carbon steel or Type 316 alloy. Kraft digesters are commonly carbon steel, though many units are partially to wholly lined with alloy materials. Type 316 most frequently. Stainless 316 is used for heater piping, strong black liquor piping and green liquor piping. Carbon steel is most frequently used for weak black liquor. Corrosion in groundwood pulping varies greatly depending on wood being ground, water supply and treating chemicals added. Stainless 304 and 316 alloys are used frequently, both to resist corrosion and reduce contamination. Chlorine and hypochlorite bleaching usually pose severe corrosion problems. Hastelloy C alloy is most commonly used for high strength solutions. In more dilute solutions the molybdenum-bearing. stainless steels are satisfactory. Chlorine dioxide is even more corrosive to metals than hypochlorite, and some operators have replaced Hastelloy C with titanium. 8.5.3

Case Study on Simultaneous Gasification of Black Liquor and Biomass in a Pulp Mill

1998 ◽  
Author(s):  
Mikael Ahlroth ◽  
Gunnar Svedberg
Keyword(s):  
High Efficiency ◽  
Black Liquor ◽  
Pulp Mill ◽  
Energy System ◽  
Limiting Factors ◽  
Fuel Quality ◽  
Hybrid Energy ◽  
Novel Approach ◽  
Substantial Investment ◽  
A Minor

One of the main limiting factors when a green field pulp mill intends to increase its production is the capacity of the Tomlinson boiler by which the cooking chemicals are recovered. Since a boiler of this kind has a service life of some thirty years and represents a substantial investment, it is not an easy decision to replace it for a minor production increase. This study takes a novel approach to the problem. The excess black liquor is assumed to be recovered in a black liquor gasifier, an emerging technology for alternative black liquor recovery. Black liquor gasification in itself has been studied considerably during the last decade. In this study it is combined with the gasification of biomass, i.e. bark and wood, which is already available at a pulp mill. The resulting hybrid energy system, with a gas turbine and a gas expander, offers interesting possibilities: good off-design performance and high efficiency with respect to the fuel quality.

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