Tel-Tek

Currently, scientists and investors consider Direct Air Capture (DAC) as one of the candidates to reduce CO2 emissions. The emissions cut is pressing since 30% of the current greenhouse gas emissions must be addressed by 2030. In seven years, CO2 removal (CDR) technologies are expected to reach a Technology Readiness Level (TRL), relevant to industrial applications. The most promising technologies are at TRL-7, but the jump to TRL-11 in the new IEA scale for disruptive technologies looks unlikely because the scale-up from small pilots to industrial scale requires time and large investments. Moreover, validation on a large scale is still missing or even unplanned. This work also identifies the critical materials supply chain and the competition with the energy transition as limiting factors which could further hinder DAC deployment and reduce DAC contribution in the next years when a first significant emissions cut should be addressed.

Condensation in raw biogas during compression is a problem because the CO2 and water in the liquid phase is very corrosive. Raw biogas typically contains 60 mol-% methane, 40 mol-% CO2, is saturated with water and may contain contaminants as ammonia (NH3). In case of NH3, it is of interest whether it has influence on the dew point (condensation) temperature. The aim of this work is to calculate the dew point under different conditions using different equilibrium models. Phase envelopes showing the two-phase area are also calculated. For dry mixtures of methane and CO2 with up to 1 mol-% NH3 (a high value for biogas), the different models gave similar results. When the NH3 increased from 0 to 1 mol-%, the dew point temperature increased with approximately 3 K. When water was included, the amount of calculated NH3 dissolved in water varied considerably with the model. The electrolyte based models Sour PR, Sour SRK and Electrolyte NRTL did not calculate reasonable dew point temperatures, but the dissolved amounts of NH3 and CO2 were more reasonable using the electrolyte models compared to using PR or SRK. For biogas simulation including NH3, a simple equation of state as PR or SRK can be recommended to determine the dew point. If accurate composition of the condensed liquid is to be calculated, an electrolyte based model like Sour PR, Sour SRK or the Electrolyte NRTL is recommended.

The industrial deployment of amine-based CO2 capture technology requires large investments as well as extensive energy supply for desorption. Therefore, the need for efficient cost and economic analysis aimed at CO2 capture investment and operating costs is imperative. Aspen HYSYS simulations of an 85% CO2 absorption and desorption process for flue gas from cement industry, followed by cost estimation have been performed. This is to study the cost implications of different plants options. Each plant option has a different lean/rich heat exchanger type. Cost optimisation of the different heat exchangers is also done in this work. Three different shell and tube and two plate and frame heat exchangers have been examined. The minimum CO2 capture cost of 57.9/ton CO2 is obtained for a capture plant option having a gasketed-plate heat exchanger with min of 5 as the lean/rich heat exchanger. The use of plate and frame heat exchangers will result in considerable CO2 capture cost reduction.

Abstract The article discusses issues related with storage of granular materials in silos made of corrugated sheets and reinforced with vertical ribs. Advantages and disadvantages of these structures are named, and typical technological solutions used by largest silo producers are presented. Moreover, basic assumptions of Eurocode 3 are discussed in the context of determining the buckling load capacity of a ribbed jacket. Alternative methods are indicated to determine the silo stability using analytical and FEM based methods. General conclusions are formulated with respect to designing of silos made of corrugated sheets.

Abstract Drill cuttings generated by offshore drilling operations are handled as a hazardous waste. In sensitive marine environments, the concept of zero discharge of waste is implemented. Hence, the drill cuttings have to be stored within the drilling rig for a short time period until they are transported to the onshore treatment facilities. As the drill cuttings are wet and sticky, conventional single silos may face the problem of blockage and rat holing. This preliminary study focuses on conducting flow property measurements. From the experiments the hopper angle and the required minimum outlet width were calculated. A plane symmetric silo with 25.8° hopper angle is suitable for all the conditions. The viscosity of the fluids is affecting the results significantly.

ABSTRACTIn this study, the feasibility of two techniques for real-time monitoring of scale deposition thickness were evaluated. Traditional pressure drop measurements and a variant of the heat pulse monitoring technique which was developed in this study were tested and compared in a lab scale experiment. Measurements were performed on test pipes while transportation air was led through the conveying system. Coating layers of different thicknesses were applied to the inner walls of the test pipes to simulate scaling. Prediction models were calibrated from the experimental data by multivariate methods and were used to assess the performance of the techniques. It was found that the heat pulse method provided the most accurate predictions for scale thickness. The pressure drop method did not give acceptable results for the application considered in this paper. Results show that the heat pulse method is somewhat sensitive to changes in the feed air temperature. However, it will still provide reliable results for online monitoring of industrial applications in which the conveying air temperature is relatively stable.