This master thesis describes the development of an UPS module. UPS is an acronym for Uninterruptable Power Supply. The UPS module has been developed at the company AerotechTelub AB. The UPS module delivers the necessary voltage and current in case of a power interrupt. If a power interrupt occur, the computer system has one to three minutes available to store data and shut down correctly. The UPS module consists of two parallel systems. Every system is built out of four parts. Part one consists of batteries and safety circuits, part two charges the batteries, partthree is a control unit, and part four delivers the voltage and current. The delivered voltage is 5 V and the current is 4 A. Tests and verifications showed that the UPS module could supply a computer system with power for about one minute. The tests have been performed in a lab at AerotechTelub AB. The UPS module is supposed to be mounted in a cassette. The cassette is then inserted in the computer system through a hole in the chassis. Thereby an opening of the computer system is avoided when the module is connected.

The kraft pulping process has been known for decades. The focus in kraft pulping has always been on better operation of the chemical recovery system. One of the targets is on deadload (sodium sulfate (Na2SO4) and sodium carbonate (Na2CO3)) reduction in white liquor. A model based on several literature references was developed to study the effect of deadload reduction. A base model was developed based on current mill operation. This base model was compared to the deadload reduction model. Overall improvement, such as operating cost saving and revenue generation was achieved from deadload reduction. Operating cost saving involves less deadload chemical in chemical recovery system, and less water that was associated with the deadload itself. Revenue generation involves generating more steam and heat from the recovery boiler that can be used for mill purposes or energy revenue. Two important variables to achieve deadload reduction are causticizing efficiency and reduction efficiency.

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This work focuses on high-temperature kraft black liquor gasification in the presence of H2O and CO2 in a laboratory-scale Laminar Entrained-Flow Reactor (LEFR). The effects of gasification conditions on hydroxide formation, carbon gasification rate, carbonate carbon and fixed carbon levels, alkali metal and sulfur species retention, and char yield were studied at atmospheric pressure and at 900-1000oC, and at residence times of 0.5-1.5 s. The results suggest that carbon gasification rates may be enhanced in the presence of H2O and CO2, with fixed carbon conversions of up to 95% at the earliest residence times at 1000oC. CO2 and H2O gasifying agents cause a significant increase in carbonate formation, with 22% of the initial carbon input forming carbonate as compared to 16% with one gasifying agent. Carbonate levels increase to a maximum level and then decrease at 900oC, but at 1000oC, carbonate decomposition processes are more dominant and cause lower levels of carbonate even at early residence times. The results show that alkali metal retention is high until vaporization occurs after 1.4 s at 900oC and at early residence times at 1000oC. Moreover, the results indicate that sulfur retention is an exothermic process, as sulfur capture increases with temperature. At 900oC, no hydroxide is produced until after 1.4 s, but at 1000oC, hydroxide appears to form readily even at the earliest residence times studied. The char product yields a maximum mole percent of 18-19% hydroxide, starting at intermediate residence times at 1000oC. Generally, hydroxide is not produced until fixed carbon conversions approach 95%. The results can be explained in terms of the interactions of phenolate and carboxylate catalytic moieties in the char product. The hydroxide formation results suggest that it may be possible to develop a gasification-causticization process that does not require external chemicals and would make the energy-efficient and environmentally friendly black liquor gasification technology an economic reality.