Thermodynamic equilibrium analysis of entrained flow gasification of spent pulping liquors

he main goal of this work is to investigate if thermodynamic equilibrium calculations can be useful for understanding and predicting process performance and product composition for entrained flow gasification of spent pulping liquors, such as black liquor. Model sensitivity to input data is studied and model results are compared to published pilot plant data. The high temperature and the catalytic activity of feedstock alkali make thermodynamic equilibrium a better predictor of product composition than for many other types of biomass and gasification technologies. Thermodynamic equilibrium calculations can predict the flows of the main syngas and slag products with high accuracy as shown by comparison with experimental data with small measurement errors. The main process deviations from equilibrium are methane formation and sulfur distribution between gas and slag. In order to study real process deviations from equilibrium, it is very important to use consistent experimental data. Relatively small errors in the model input, primarily related to fuel composition, can lead to grossly erroneous conclusions. The model sensitivity to fuel composition also shows that the gasification process is sensitive to naturally occurring feedstock variations. Simulations of a commercial-scale gasification process show that cold gas efficiency on sulfur-free basis can reach over 80 % and that greatly improved efficiency can be obtained by reducing ballast present in the form of water or inorganics.Validerad;2018;Nivå 2;2018-02-20 (rokbeg)</p

Determination of oil contents in bilge water with acoustics in combination with multivariate data analysis

Bilge water is created when ship tanks are flushed and engine rooms are cleaned with water and detergents/degreaser. The resulting oil containing bilge water is usually treated in an on-ship waste water-treatment unit. To facilitate minimization of water-treatment chemicals and to assure that the oil concentration is low enough to allow discharge in the sea, it is important to know the oil concentration in the outflow. In this work we have tested and developed passive acoustic measurements for measurement of oil concentration in bilge water. The starting point was to make synthetic bilge water to test the concept and to get information about the system, including the properties of oils used and the specifics of applying acoustic measurement to them. We investigated the effect of salt in the bilge water by modelling synthetic bilge water with and without NaCl. The prediction errors obtained was 2.5 ppm oil (samples with salt), 0.6 ppm oil (samples without salt) and 4.5 ppm oil (samples with and without salt) (0.5-18 ppm calibration range). Thereafter real samples were collected from a ship. Since the samples had either high or low oil concentration, they were mixed in order to get a representative set of calibration samples with a large range of concentrations. The oil concentrations in the samples were determined by laboratory analysis, the experiments were performed and the calibration models developed. The best model was validated using a separate test set and yielded a test set prediction error of 7.3 ppm. This can be regarded as a good result, since the average absolute error for the laboratory measurement is around 5 ppm, and acoustic measurements is a promising technology to determine oil in bilge water. Recommendations for further work is to lower the error of the laboratory reference method used to determine the oil concentration, to improve the sampling handling chain and possibly also to improve the acoustic measurement equipment before new trials are performed.Bilge water is created when ship tanks are flushed and engine rooms are cleaned with water and detergents/degreaser. The resulting oil containing bilge water is usually treated in an on-ship waste water-treatment unit. To facilitate minimization of water-treatment chemicals and to assure that the oil concentration is low enough to allow discharge in the sea, it is important to know the oil concentration in the outflow. In this work we have tested and developed passive acoustic measurements for measurement of oil concentration in bilge water. The starting point was to make synthetic bilge water to test the concept and to get information about the system, including the properties of oils used and the specifics of applying acoustic measurement to them. We investigated the effect of salt in the bilge water by modelling synthetic bilge water with and without NaCl. The prediction errors obtained was 2.5 ppm oil (samples with salt), 0.6 ppm oil (samples without salt) and 4.5 ppm oil (samples with and without salt) (0.5-18 ppm calibration range). Thereafter real samples were collected from a ship. Since the samples had either high or low oil concentration, they were mixed in order to get a representative set of calibration samples with a large range of concentrations. The oil concentrations in the samples were determined by laboratory analysis, the experiments were performed and the calibration models developed. The best model was validated using a separate test set and yielded a test set prediction error of 7.3 ppm. This can be regarded as a good result, since the average absolute error for the laboratory measurement is around 5 ppm, and acoustic measurements is a promising technology to determine oil in bilge water. Recommendations for further work is to lower the error of the laboratory reference method used to determine the oil concentration, to improve the sampling handling chain and possibly also to improve the acoustic measurement equipment before new trials are performed

REKO luft - reduktionskostnader för luftemissionsbegränsande åtgärder

I detta forskningsprojekt har IVL, i samarbete med ett antal sektorsorgan (myndigheter och andra branschintressenter), arbetat med att utveckla en databas över emissionsbegränsande åtgärder och deras kostnader. Databasen kallas REKO luft - reduktionskostnader för luftemissionsbegränsande åtgärder. I projektet har en databasstruktur tagits fram samt ett optimeringsverktyg utvecklats med vilket den mest kostnadseffektiva lösningen givet flera satta mål kan tas fram, d.v.s. verktyget kan hantera flera emissioner samt sektorer parallellt. Då många data saknas i databasen samt då befintliga data inte är kvalitetssäkrade kan databasen i dagsläget endast användas i illustrativt syfte. En av de mest kritiska punkterna för att få REKO att fungera är databiten. För att databasen ska bli användbar krävs därför att en organisation och metod för dataförsörjning, kvalitetssäkring och uppdatering av data utvecklas.I detta forskningsprojekt har IVL, i samarbete med ett antal sektorsorgan (myndigheter och andra branschintressenter), arbetat med att utveckla en databas över emissionsbegränsande åtgärder och deras kostnader. Databasen kallas REKO luft - reduktionskostnader för luftemissionsbegränsande åtgärder. I projektet har en databasstruktur tagits fram samt ett optimeringsverktyg utvecklats med vilket den mest kostnadseffektiva lösningen givet flera satta mål kan tas fram, d.v.s. verktyget kan hantera flera emissioner samt sektorer parallellt. Då många data saknas i databasen samt då befintliga data inte är kvalitetssäkrade kan databasen i dagsläget endast användas i illustrativt syfte. En av de mest kritiska punkterna för att få REKO att fungera är databiten. För att databasen ska bli användbar krävs därför att en organisation och metod för dataförsörjning, kvalitetssäkring och uppdatering av data utvecklas

Production optimisation in the petrochemical industry by hierarchical multivariate modelling

This project demonstrates the advantages of applying hierarchical multivariate modelling in the petrochemical industry in order to increase knowledge of the total process. The models indicate possible ways to optimise the process regarding the use of energy and raw material, which is directly linked to the environmental impact of the process. The refinery of Nynäs Refining AB (Gothenburg, Sweden) has acted as a demonstration site in this project. The models developed for the demonstration site resulted in: * Detection of an unknown process disturbance and suggestions of possible causes. · Indications on how to increase the yield in combination with energy savings. * The possibility to predict product quality from on-line process measurements, making the results available at a higher frequency than customary laboratory analysis. * Quantification of the gradually lowered efficiency of heat transfer in the furnace and increased fuel consumption as an effect of soot build-up on the furnace coils. * Increased knowledge of the relation between production rate and the efficiency of the heat exchangers. This report is one of two reports from the project. It contains a technical discussion of the result with some degree of detail. A shorter and more easily accessible report is also available, see IVL report B1586-AThis project demonstrates the advantages of applying hierarchical multivariate modelling in the petrochemical industry in order to increase knowledge of the total process. The models indicate possible ways to optimise the process regarding the use of energy and raw material, which is directly linked to the environmental impact of the process. The refinery of Nynäs Refining AB (Gothenburg, Sweden) has acted as a demonstration site in this project. The models developed for the demonstration site resulted in: * Detection of an unknown process disturbance and suggestions of possible causes. · Indications on how to increase the yield in combination with energy savings. * The possibility to predict product quality from on-line process measurements, making the results available at a higher frequency than customary laboratory analysis. * Quantification of the gradually lowered efficiency of heat transfer in the furnace and increased fuel consumption as an effect of soot build-up on the furnace coils. * Increased knowledge of the relation between production rate and the efficiency of the heat exchangers. This report is one of two reports from the project. It contains a technical discussion of the result with some degree of detail. A shorter and more easily accessible report is also available, see IVL report B1586-

A model of an integrated hydrothermal liquefaction, gasification and Fischer-Tropsch synthesis process for converting lignocellulosic forest residues into hydrocarbons

The aim of this work was to develop a model of an integrated biomass-to-liquid process, consisting of hydrothermal liquefaction, evaporation, gasification and Fischer-Tropsch synthesis, using lignocellulosic forest residues as feedstock to produce hydrocarbons suitable for upgrade into drop-in biofuels. The energy, mass and carbon efficiencies that were achieved were 35%, 20% and 32%, respectively. The Fischer-Tropsch crude carbon chain length distribution peaked at carbon chain length 10 with a heavy right tail (a profile favourable for upgrade to jet fuel). A life cycle assessment showed high greenhouse gas performances for production plants in a Norrbotten coastal area and in Kalmar, both in Sweden. The reductions in life cycle greenhouse gas emissions (versus the fossil fuel comparator and according to the European Union Renewable Energy Directive II) were 85–95% for the Fischer-Tropsch crude produced in Norrbotten, and 92–97% in Kalmar, depending on the transportation distances and feedstock used

Co-gasification of pyrolysis oil and black liquor for methanol production

Godkänd; 2013; 20131213 (joakim

On the role of potassium as a tar and soot inhibitor in biomass gasification

The work investigates in a drop tube furnace the effect of potassium on carbon conversion for three different types of fuels: an ash lean stemwood, a calcium-rich bark and a silicon-rich straw. The study focuses on an optimal method for impregnating the biomass with potassium. The experiments are conducted for 3 different impregnation methods; wet impregnation, spray impregnation, and dry mixing to investigate different levels of contact between the fuel and the potassium. Potassium is found to catalyse both homogenous and heterogeneous reactions. All the impregnation methods showed a significant effect of potassium on heterogeneous reactions (char conversion). The fact that dry mixing of potassium in the biomass shows an effect reveals the existence of a gas-induced mechanism that supply and distributes potassium on the char particles. Concerning the effect of potassium on homogenous reactions, it is found that potassium in the gas phase leads to much lower yields of C2 hydrocarbons, heavy tars and soot. The results indicate that potassium reduces the likelihood of light aromatic to progress toward heavier polyaromatic hydrocarbons clusters, thereby inhibiting the formation of soot-like material. A moderate interaction between the added potassium and the inherent ash forming elements is also observed: Potassium has a smaller effect when the fuel is naturally rich in silicon. The combined results are of interest for the design of a gasification process that incorporates recirculation of naturally occurring potassium to improve entrained flow gasification of biomass. Funding details: Energimyndigheten, 43207-1; Funding details: Kempestiftelserna; Funding text 1: We thank the Swedish Energy Agency for supporting this work through “catalytic entrained flow gasification of biomass (project number: 43207-1)”, and the Kempe Foundation for the financial support to construct the equipment. The authors would also like to express their gratitude to Ali Hedayati and Maria Roudiouchkina for their invaluable help with the SEM/EDS analysis.</p

Fuel conversion characteristics of black liquor and pyrolysis oil mixture for efficient gasification with inherent catalyst

This paper describes the technical feasibility of a catalytic co-gasification process using a mixture of black liquor (BL) and pyrolysis oil (PO). A technical concern is if gasifiers can be operated at low temperature (~1000 ºC) without problems of tar, soot or char, as is the case for pure BL due to the catalytic effect of fuel alkali. Hence, we investigated fuel conversion characteristics of BL/PO mixture: conversion of single droplet in flame, and char gasification reactivity. 20wt.% (BP20) and 30wt.% (BP30) were selected for weight fraction of PO because of lignin precipitation in BP30. Single droplet was devolatilized and gasified in a methane flame with a flat flame burner at various droplet sizes. Conversion time and swelling ratio were investigated with imaging. They were more sensitive to initial droplet size and reaction atmosphere than the mixing of BL and PO. Char gasification reactivity was measured in an isothermal thermogravimeter (iTG) at T=880–940 ºC and PCO2=1 bar. Both BP20 and BP30 showed complete char conversion and there was no statistically significant difference in char reactivity among BP20, BP30 and BL. These results show that PO can be co-gasified in BL gasification process without major changes in the operation.Godkänd; 2014; 20140830 (umeken

Vägtrafikens bidrag till PM10 och metaller vid tätorts- och landsvägskörning

Trafikens påverkan på halter av PM10 och 25 metaller har studerats, med syfte att bedöma om denna påverkan skiljer sig mellan tätortskörning och landsvägskörning. För att identifiera den andel av partiklar och metaller som härrör från trafiken har multivariat receptormodellering genomförts. Härigenom identifierades fem källor - uppvirvling av vägdamm, bromsar, vägsalt, regional förbränning och bakgrund. Bromsar är av stor betydelse för PM10 vid tätortskörning, men av liten betydelse vid landsväg. Koppar, Ba, Pb, Sb och Zn är exempel på metaller som i stor utsträckning härrör från bromsar, medan förekomsten av framförallt Cd och Tl helt domineras av bakgrundsbidraget.Trafikens påverkan på halter av PM10 och 25 metaller har studerats, med syfte att bedöma om denna påverkan skiljer sig mellan tätortskörning och landsvägskörning. För att identifiera den andel av partiklar och metaller som härrör från trafiken har multivariat receptormodellering genomförts. Härigenom identifierades fem källor - uppvirvling av vägdamm, bromsar, vägsalt, regional förbränning och bakgrund. Bromsar är av stor betydelse för PM10 vid tätortskörning, men av liten betydelse vid landsväg. Koppar, Ba, Pb, Sb och Zn är exempel på metaller som i stor utsträckning härrör från bromsar, medan förekomsten av framförallt Cd och Tl helt domineras av bakgrundsbidraget