Vattenfall

About: Vattenfall is a company organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Wind power & Combustion. The organization has 685 authors who have published 857 publications receiving 18912 citations. The organization is also known as: Vattenfall AB & Kungliga Vattenfallstyrelsen.

Corrosion of TP347H FG stainless steel in a biomass fired PF utility boiler

Abstract: Detailed microscopic examinations have been conducted on two, temperature-regulated probes which had been exposed to biomass flue gas inside a PF boiler for 3770 h at 600° and 650°C respectively. The two probes were made from commercial grade heat exchanger alloy (TP 347H FG). A significant buildup of potassium chloride and sulphate was found on both probes within the deposits that sinter more strongly on the 650°C probe. Both probes suffer extensive intergranular corrosion as well as general corrosion. The higher temperature enhances scale formation which may provide a beneficial effect with respect to hot corrosion resistance. The intergranular corrosion is linked to the presence of sulphur. The overall material wastage is almost the same for both probes and for different locations covered by deposit.

An 865 MW Lignite Fired CO2 Free Power Plant - A Technical Feasibility Study

Abstract: Publisher Summary This chapter introduces O 2 /CO 2 concept to commercial data from an 865 MWe lignite fired reference power plant and large air separation units (ASU). O 2 /CO 2 combustion involves burning the fuel in an atmosphere of oxygen and recycled flue gas instead of in air. The mixed flow of oxygen and recycled flue gas is fed to the boiler together with the fuel, which is burnt as in a conventional plant. Typically, 70-80% of the flue gas is recycled from down stream the economizer and mixed with new oxygen. The remaining part of the flue gas is cleaned, compressed and later transported to storage or to another application. Studies on O 2 /CO 2 combustion have mainly concerned emissions and combustion behavior. It identifies essential components and energy streams of the two processes and investigates the possibilities for process integration. A detailed design of the flue gas treatment before transportation of the separated carbon dioxide has also been proposed. The sulphur dioxide can be sequestered together with the carbon dioxide, provided that the gas is dry, and, consequently, there is no need for a desulphurizing unit. Because the investment cost of an ASU is slightly lower than for the desulphurizing unit, the investment cost of the O 2 /CO 2 plant will be slightly lower than for the reference plant. With all identified integration possibilities the net electrical efficiency becomes 34.3%, which is a reduction by 8.3 percent units compared to the reference plant.

Amorphous Metal core material shows economic and environmental benefits when pre-existing transformers are to be replaced within Vattenfall Group´s distribution network

Abstract: This paper describes Amorphous Metal core Distribution Transformers (AMDT) and its potential to obtain economic and environmental benefits when pre-existing transformers are to be replaced. Vattenfall's ambition is to decrease losses within the Vattenfall Group's distribution network, thus contributing to the environment and economy, and hence confirm that this is an important issue for Vattenfall. Distribution transformers within the Vattenfall Group's distribution network in Sweden, Germany and Poland are investigated and presented in three different business cases that consider the current sizes, quantities, ages and load utilization. The inventory of the distribution transformers used at Vattenfall, indicates that conventional transformers of fairly high loss types have been selected over low loss types. Choosing low loss amorphous transformers when pre-existing transformers are to be replaced, means that the CO 2 emission will be significantly reduced. AMDT have the potential to reduce transformer no-load losses by up to 70% compared to conventional technology. This paper discusses the general aspects of AMDT transformer losses as well as the importance of using the Total Ownership Cost (TOC) method to determine the economic benefits whenever a unit is to be purchased.