Advanced Online Process Analyzer for Chemical Recovery and Pulp Mill Control

2020 ◽  
Vol 74 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Thanh Trung ◽  
Tomohide Mogami
Author(s):  
GUSTAVO M. DE ALMEIDA ◽  
MARCELO CARDOSO ◽  
DANILO C. RENA ◽  
SONG W. PARK

The extraction of information from tabular data is not a natural task for human beings, which is worse when dealing with high dimensional systems. On the other hand, graphical representations make the understanding easier by exploring the human capacity of processing visual information. Such representations can be used for many purposes, e.g., complex systems structuring which contributes to a better understanding of it. This paper constructs a cause-effect map relating the influence of each input process variable on the steam generated by a boiler. The real case study is based on the operations of a chemical recovery boiler of a Kraft pulp mill in Brazil. The map is obtained by two steps, namely the identification of a neural predictive model for the steam and a study of sensitivity analysis. The numerical results are then depicted in a graphical format using a cause-effect map. This representation highlights the relative importance of the predictor variables to the steam generation. The results, in agreement with the literature, show the higher contribution of the heat released during the fuel burning, and the lower influence of both the fuel temperature and the operating variables associated with the primary level of injection of the combustion air.


2010 ◽  
Vol 45 (2) ◽  
pp. 163-173 ◽  
Author(s):  
Deborah L. MacLatchy ◽  
Craig Milestone ◽  
Kevin S. Shaughnessy ◽  
Andrew M. Belknap ◽  
Monique G. Dubé ◽  
...  

Abstract An investigation of cause (IOC) approach integrating artificial stream exposures and laboratory bioassays has been used to identify waste stream sources of contaminants at the Irving Pulp & Paper Ltd. mill, in Saint John, New Brunswick, Canada. Chemical recovery condensates have shown the greatest potential for reducing circulating steroids in mummichog (Fundulus heteroclitus), an endemic fish species. A solid phase extraction (SPE) technique was developed to isolate hormonally active substances from the condensates, and a toxicity identification evaluation approach was used to gain a better understanding of the chemical characteristics of the active substances. Extracts were fractionated by high performance liquid chromatography (HPLC) and the fractions were used in a seven-day bioassay. Dose-response experiments indicated that steroid reductions in male mummichog were observed consistently after a 4% (vol/vol) exposure. At 4% (vol/vol), however, steroid reductions were not observed in fractions of the active SPE extract generated by HPLC. Some fractions actually induced increases in plasma testosterone. Recent work has focused on understanding what methodologies must be used to handle the semivolatile condensates to ensure 100% chemical recovery and retention of biological activity. Results are summarized in the context of developing an industry-wide IOC framework.


TAPPI Journal ◽  
2013 ◽  
Vol 12 (2) ◽  
pp. 41-53 ◽  
Author(s):  
JOHN D. ANDREWS ◽  
PETER W. HART

Researchers have been attempting to improve the yield of bleachable-grade kraft pulp for several decades. Wood is typically one of the major costs associated with kraft pulping. Therefore, it is typically assumed that improving pulp yield or conversely, reducing the amount of wood required to make a specific mass of pulp, is a cost-effective, lucrative endeavor. Although this may be true, it is important to understand the impact of increasing pulp yield on the interconnected processes within an integrated pulp and paper mill and to fully evaluate the cost implications on these processes. The current work employed several sets of laboratory pulping conditions and a WinGEMS model of a pulp mill, fully integrated with chemical recovery, power, and recausticization, and pulp drying islands to determine where the largest cost impact associated with improved pulp yield may be experienced.


TAPPI Journal ◽  
2012 ◽  
Vol 11 (9) ◽  
pp. 19-27 ◽  
Author(s):  
HEIKKI KORPUNEN ◽  
PEKKA VIRTANEN ◽  
OLLI DAHL ◽  
PAULA JYLHÄ ◽  
JORI UUSITALO

This study introduces an activity-based costing (ABC) method for a kraft pulp mill. Our ABC model defines the production resources and costs for each process in a chemical pulp mill and allocates the costs to pulp, energy, bark, turpentine, and crude tall oil. The production processes include receiving, unloading and debarking of pulpwood, chipping, chip screening, chip storing, cooking and in-digester washing, pulp washing and screening, oxygen delignification, bleaching, drying, and chemical recovery. We also tested the effect of Scots pine pulpwood properties on the profitability of a virtual greenfield pulp mill located in Finland, where it produced 600000 air-dried (a.d.) metric tons of bleached market pulp annually. Total annual production costs were approximately EUR 216 million (USD 285 million), of which chemical recovery comprised the biggest share (almost 39%). According to the results, the price of market pulp had the most significant effect on the profitability of the mill. The pulpwood properties did not clearly affect pulp production costs; the wood procurement costs had more influence on the profitability of the value chain. Our results also indicate that the profitability of pulp making is strongly dependent on the prices of electricity and heat. This is because the mill is customer and seller in energy markets. ABC proved to be a useful tool and accurate method for cost calculation in this highly competitive branch of the forest industry.


1961 ◽  
Vol 53 (10) ◽  
pp. 773-778 ◽  
Author(s):  
D. Gray Weaver ◽  
W. A. Biggs

TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 33-39
Author(s):  
MARCELO HAMAGUCHI ◽  
ESA K. VAKKILAINEN

The main objective of this study is to evaluate the effect of chlorine (Cl) and potassium (K) on the operation and design of equipment in the chemical recovery cycle. Due to stricter environmental regulations, mill closure tends to increase, causing the accumulation of undesirable elements such as Cl and K in the kraft liquor cycle. Total inorganic solids in pulping liquors increase in the presence of Cl and K, which affects the operation of chemical recovery equipment. The objective here is to show the magnitude of these impacts and estimate operational cost differences by using different Cl and K contents in liquors. Pulp mill material and energy balances for each case are used for this purpose, and a modern Brazilian pulp mill served as a base case model. The results show that for one specific range, the solids content in black liquor can be 6.6% higher by increasing the mass percentage of Cl and K in black liquor. This difference reduces the black liquor higher heating value by 6.2% and increases the amount of dry solids to burn in the recovery boiler, also by 6.6%. The evaporation load increases along with steam consumption. This lowers total electricity output by up to 1.6 MW due to reduced flow to the condensing stage of the steam turbine. The balances also demonstrate that some pumping costs can be 12% higher when operating from a low to high concentration of Cl and K in black liquor.


TAPPI Journal ◽  
2012 ◽  
Vol 11 (9) ◽  
pp. 53-59 ◽  
Author(s):  
NIKLAS VÄHÄ-SAVO ◽  
NIKOLAI DEMARTINI, ◽  
MIKKO HUPA

At many mills, biosludge, which has a high nitrogen content, is added to black liquor and burned in kraft recovery boilers. The aim of this work was to determine the fate of biosludge nitrogen in the high solids black liquor concentrators and in the recovery boiler. Specifically, does biosludge addition result in higher nitric oxide (NO) and cyanate formation during black liquor combustion? To obtain this information, samples were collected from the chemical recovery cycle of a Finnish kraft pulp mill along with relevant process data. Laboratory combustion experiments clearly showed an increase in NO formation for the mill black liquor with biosludge, but no clear increase in nitrogen oxide emissions was detected in the recovery boiler after biosludge addition. Analysis of the green liquor samples from the dissolving tank showed a significant increase in nitrogen exiting the recovery boiler as cyanate. This finding was supported by laboratory tests studying cyanate formation. The increased cyanate results in increased ammonia formation in the recausticizing cycle, which can lead to higher NO emissions, as seen in the noncondensible gas incinerator at the mill.


2012 ◽  
Vol 610-613 ◽  
pp. 2429-2432 ◽  
Author(s):  
Kai Tang Hu ◽  
Ming Li ◽  
Bing Hu

The different refining processes of lime mud, including water washing, drying and adding auxiliaries from chemical recovery of black liquor from reed pulp mill were studied in the article. The convenient and effective technologies of refining lime mud for CaCO3used as papermaking fillers with less water consumption were optimized and discussed. The experimental results showed that the brightness of the CaCO3refined is 84~86%(ISO), and water consumption is about 30~50 ton for one ton’s lime mud by the washing processes, and the brightness of the CaCO3refined is 88~89%(ISO) by the drying processes, and the lowest water consumption is about 3~6 tons for one ton’s lime mud by the adding auxiliaries peocess. With the optimum process, the carbonizing temperature is about 50°C, and the brightness of CaCO3refined is 91.5%(ISO). Total water consumption in the processes is only about 5~10 tons for one ton lime mud.


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