Utilization of Organic Mixed Biosludge from Pulp and Paper Industries and Green Waste as Carbon Sources in Blast Furnace Hot Metal Production

Abstract

A six day industrial trial using hydrochar as part of the carbon source for hot metal production was performed in a production blast furnace (BF). The hydrochar came from two types of feedstocks, namely an organic mixed biosludge generated from pulp and paper production and an organic green waste residue. These sludges and residues were upgraded to hydrochar in the form of pellets by using a hydrothermal carbonization (HTC) technology. Then, the hydrochar pellets were pressed into briquettes together with commonly used briquetting material (in-plant fines such as fines from pellets and scraps, dust, etc. generated from the steel plant) and the briquettes were top charged into the blast furnace. In total, 418 tons of hydrochar briquettes were produced. The aim of the trials was to investigate the stability and productivity of the blast furnace during charging of these experimental briquettes. The results show that briquettes containing hydrochar from pulp and paper industries waste and green waste can partially be used for charging in blast furnaces together with conventional briquettes. Most of the technological parameters of the BF process, such as the production rate of hot metal (<1.5% difference between reference days and trial days), amount of dust, fuel rate and amount of injected coal, amount of slag, as well as contents of FeO in slag and %C, %S and %P in the hot metal in the experimental trials were very similar compared to those in the reference periods (two days before and two days after the trials) without using these experimental charge materials. Thus, it was proven that hydrochar derived from various types of organic residues could be used for metallurgical applications. While in this trial campaign only small amounts of hydrochar were used, nevertheless, these positive results support our efforts to perform more in-depth investigations in this direction in the future.

A Review of Upscaling Hydrothermal Carbonization

“…Each modular unit has a capacity of 6000 T/year of wet biomass. Ingelia's HTC process can also treat different feedstocks with a moisture content in the range of 30-90% inside inverted flow reactors for a continuous process and generate biocoal and liquid fertilizer [103][104][105]. Different from the AVA-CO 2 plant, a pretreatment process is employed in the Ingelia HTC plant to mill the input feedstock into a particle size of below 8mm and then pump it into the reactor through a long pre-heating tube.…”

Applications of Hydrochar and Charcoal in the Iron and Steelmaking Industry—Part 1: Characterization of Carbonaceous Materials

“…Apart from BF tuyere injection, Jarnerud et al [44] studied the feasibility of using hydrochar as a reducing reagent for the BF process. Hydrochar briquettes (2 wt% hydrochar, 12 wt% cement, and 86 wt% in-plant fines) were prepared and top-charged into a BF to substitute 10-40% of the conventional top-charged pellets (8 wt% cement, 92 wt% in-plant fines) for six experimental trials (1 day per trial).…”

Development of a Continuous Hydrothermal Treatment Process for Efficient Dewatering of Industrial Wastewater Sludge

“…Fiber sludge is composed of short cellulose fibers and is obtained from primary clarification in the wastewater treatment process. The addition of Processes 2022, 10, 2702 2 of 15 fiber sludge to bio-sludge to form a mixed sludge enhances the overall dewaterability via mechanical dewatering, which is highly preferred over thermal dewatering [8,9]. However, the use of fiber sludge as a dewatering aid is not ideal as it is rich in cellulose fibers and organics and therefore has the potential for reuse as a raw material in the papermaking process [5].…”