| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Carlsson, Per, et al.
(författare)
-
Experimental investigation of an industrial scale black liquor gasifier : 1. Influence of reactor operation parameters on product gas composition
- 2010
-
Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 89:12, s. 4025-4034
-
Tidskriftsartikel (refereegranskat)abstract
- A novel technology to mitigate the climate changes and improve energy security is Pressurized Entrained flow High Temperature Black Liquor Gasification (PEHT-BLG) in combination with an efficient fuel synthesis using the resulting syngas. In order to optimise the technology for use in a pulp and paper mill based biorefinery, it is of great importance to understand how the operational parameters of the gasifier affect the product gas composition. The present paper is based on experiments where gas samples were withdrawn from the hot part of a 3 MW entrained flow pressurized black liquor gasifier of semi industrial scale using a high temperature gas sampling system. Specifically, the influence of process conditions on product gas composition (CO2, CO, H2, CH4, H2S, and COS) were examined by systematically varying the operational parameters: system pressure, oxygen to black liquor equivalence ratio, black liquor flow rate to pressure ratio and black liquor pre-heat temperature. Due to the harsh environment inside the gasification reactor, gas sampling is a challenging task. However, for the purpose of the current study, a specially designed high temperature gas sampling system was successfully developed and used. The results, obtained from two separate experimental campaigns, show that all of the investigated operational parameters have a significant influence on the product gas composition and present valuable information about to the process characteristics.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Nordgren, Daniel, et al.
(författare)
-
Studies of heat transfer and furnace temperature uniformity during combustion of oil and wood using oxygen enrichment technology
- 2011
-
Ingår i: Swedish-Finnish Flame Days 2011.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In many combustion applications a switch from fossil to renewable fuels, e.g. from fueloil to wood powder, may result in a reduction of production capacity in the boiler,furnace or kiln. Oxygen enrichment of the combustion air can be used to improve thethermal efficiency of practical combustors, i.e. reduce heat losses and promote fuelsavings. In addition, oxygen enrichment can reduce NOx emissions and also facilitateCO2 scrubbing and capture processes in such systems. In this work, flame characteristicsand furnace temperature profiles during oxygen enriched combustion were studied whenoxygen was added to the combustor at different enrichment levels by the use of a lance.The experiments were carried out in a pilot-scale furnace fired with (i) wood powder and(ii) heavy fuel oil (no.5). The results show that for the wood flame, the average furnacetemperature becomes higher and the furnace temperature profile becomes more flat.Thus, compared to conventional air combustion, there are smaller differences betweennear-burner and back-end temperatures as oxygen is added to the process. For the oilflame, as oxygen was added to the process, a higher average furnace temperature wasobserved along with a distinct shift in furnace peak temperature towards the central partsof the furnace, creating a relatively strong temperature gradient towards the back-end ofthe furnace. Comparing the two flames, the furnace temperature profile of the oxygenenriched wood flame becomes more flat compared to the oxygen enriched oil flame. Thisis interpreted as an effect of differences in overall fuel reactivity, in which the oil, being aliquid fuel, ignites and burns faster than the solid fuel wood powder. The results found inthis work shows that the burner that was used, being designed for conventional aircombustion by feeding of air through the primary, secondary and tertiary air vanes, couldhandle the changes in aerodynamics caused by the reduced air flows. The general resultsfrom this work are useful for furnace and kiln applications in which a more controllableflame and process temperature is required, e.g. in a lime kiln where a fuel switch fromfossil fuels to biomass is considered.
|
|
| 10. |
- Wiinikka, Henrik, et al.
(författare)
-
Emissions of heavy metals during fixed-bed combustion of six biomass fuels
- 2013
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 27:2, s. 1073-1080
-
Tidskriftsartikel (refereegranskat)abstract
- Few studies examine heavy metal emissions during the small-scale combustion of various solid biofuels. This issue may become more important, as one can expect new regulations governing such emissions from biomass combustion similar to those governing waste incineration. This paper investigates the emissions of particulate-associated heavy metals (i.e., Sb, As, Cd, Co, Cr, Cu, Pb, Mn, Ni, Tl, V, Hg, and Zn) during the fixed-bed combustion of six solid biofuels (i.e., stemwood from birch and pine/spruce, bark from birch and pine, salix, and oat grains) and of peat and bituminous coal for comparison. The results indicate that the flue gas concentration (normalized to 11% O2) of the sum of all measured metals (Zn excluded) during the biomass combustion tests ranged from 57 μg Nm-3 for birch stemwood to 198 μg Nm-3 for birch bark. The concentration of Zn in the flue gas was generally considerably higher than those of the other metals, ranging from 646 μg Nm-3 for spruce/pine stemwood to 7948 μg Nm-3 for birch bark. Compared with coal and peat, the biomass fuels produced higher Zn emissions, but lower or similar emissions of the sum of the other metals. The volatile behavior and concentration of the metal in the flue gases as a function of the heavy metal in the fuel are also presented for selected heavy metals.
|
|
