Activated Carbon and Process for Making Same

A process is described for the manufacture of activated carbon in the form of a powder, as granules or as extrudates. The process includes treating a biomass feedstock, such as woods, coconut shells, fruit pits, peats, lignites and all ranks of coal with a processing agent and an activation agent. The processing agent may be a natural or synthetic monomer, oligomer, polymer or mixtures thereof capable of interacting or co-polymerizing with the biomass feedstock. The activation agent may be, for example, phosphoric acid, zinc chloride or mixtures thereof. A high surface area, high hardness extruded activated carbon may be produced by this process. The activated carbon is generally characterized by a BET surface area between 600-2500 m2 /g, a mesopore surface area between 80-900 m2 /g and for extruded or granular carbons, a Takeda hardness of between 10-50%

Carbon Fiber for Air Filtration

Described are filters containing free-activated carbon fibers or activated carbon fibers in the form of a composite used for filtering a variety of contaminants, including pathogens, from air. These filters can provide effective and efficient removal of contaminants from air, requiring only short contact time between the air being filtered and the filter itself, with only a minimum pressure drop across the filter. The characteristics of these filters allow for effective filtration with only thin filter layers being required. The process of filtering air utilizing these filters is also disclosed

Hybrid Dynamic Surrogate Modelling for a Once-Through Steam Generator

Hybrid Dynamic Surrogate Modelling for a Once-Through Steam GeneratorFour surrogate modelling techniques are compared in the context of modelling once-through steam generators (OTSGs) for offshore combined cycle gas turbines (GTCCs): Linear and polynomial regression, Gaussian process regression and neural networks for regression. Both fully data-driven models and hybrid models based on residual modelling are explored. We find that speed-ups on the order of 10k are achievable while keeping root mean squared error at less than 1%. Our work demonstrates the feasibility of developing OTSG surrogate models suitable for real-time operational optimization in a digital twin context. This may accelerate the adoption of GTCCs in offshore industry and potentially contribute towards a 25% reduction in emissions from oil & gas platforms.acceptedVersio

Achieving 50% weight reduction of offshore steam bottoming cycles

Adding a bottoming cycle to the gas turbines powering offshore oil and gas production plants allows additional power to be produced from recovered excess heat. Hence, the power demand of the platform can be met by burning less natural gas, and the CO2 emissions reduced by up to 25%. However, the weight of the current bottoming cycles must come down to enable widespread implementation. This work presents a thorough weight minimization of a steam bottoming cycle utilizing gas turbine exhaust heat. Unconventional, but feasible designs of heat exchangers, ductwork and structural components are considered along with materials switching. Overall weight reductions of 38% and 52% were achieved for a 16 MW and a 12 MW offshore bottoming cycle respectively when compared to a 16 MW reference system. Key factors in achieving the weight reduction were the use of small steam generator tubes with an inner diameter of only 10 mm, improved condenser design and the use of aluminium structural framework replacing steel. By more than halving the weight of the bottoming cycle, it's implementation potential on offshore platforms has been greatly improved and can move the oil and gas industry towards significantly reduced CO2 emissions.publishedVersio

Design optimization of compact gas turbine and steam combined cycles for combined heat and power production in a FPSO system–A case study

This case study aims to cover a wide range of relevant aspects related to combined cycle design, mechanical integrity and operational reliability for cogeneration of heat and power in FPSO systems. The methods consist of combined optimization of combined cycle thermodynamic design and geometry of steam generator; vibration analysis for flow induced vibrations; and thermal stress estimation of casings during cold start-stop scenarios. Challenges and opportunities for reliable water treatment systems are explored. The results show that small tubes, a compact tube bundle and a low condensation temperature reduces the once-trough steam generator (OTSG) weight. The vibrations numerical simulations in this work support the standard recommendations of using 35 times tube OD as upper limit for the unsupported tube length, which could be used as a reasonable design criterion. Thermal stresses analysis indicates that the design of beam arrangement, location, and stiffness of beams has a major impact on thermal stresses, and can be optimized to different plate thicknesses in order to avoid fatigue damage. Focus should be on reducing leaks of deaerator, steam turbine and condenser. It is recommended to add Na sensors after condenser and investigating the use of Electrodeionization (EDI) technology for make-up water production from seawater.publishedVersio

Carbon Fiber Filters

Disclosed is a filter comprised of activated carbon fibers, wherein said filter has a Virus Removal Index (hereafter “VRI”) of at least about 99%, as measured in accordance with the test method described in the specification. The filter may comprise unbound fibers, or the fibers may be bound with a binder to form a composite of fibers. Also disclosed is a method of removing viruses from a liquid, the method comprising contacting the liquid with a filter comprising activated carbon fibers wherein said filter has a VRI of at least about 99%. Also described is an article of manufacture comprising: (a) a filter comprising activated carbon fibers, wherein said filter has a VRI of at least about 99%; and (b) instructions which inform a user that the filter may be used to remove viruses from a liquid

Low carbon power generation for offshore oil and gas production

Emission reductions in power generation for offshore oil and gas activities are key in order to reach climate targets in regions with this industry. This study presents a review of both established and immature low carbon power generation concepts, an analysis of their potential for greenhouse gas (GHG) emission reduction, and an evaluation of their offshore applicability. The potential for GHG emission reduction is quantified by estimating CO2 equivalent intensity for implementation on the Norwegian Continental Shelf. The offshore applicability is evaluated with emphasis on weight, infrastructure requirements, process heat availability, technical maturity, as well as health, safety, and environment (HSE). It is shown that power from shore is the only technically mature concept with potential for very high emission reductions (>95 %, provided that low GHG electric power is available). There are several alternative concepts under development that also can give significant emission reductions (>70 %), including fuel switching, CO2 capture and storage, and renewable power combined with energy storage. Combined cycle gas turbines and offshore wind power combined with gas turbines are technically mature and can achieve partial emission reductions (around 15–50 %, with the assumed system configurations). Other concepts offering partial emission reductions are under development, but do not show clear advantages over those already mentioned. It is pointed out that, to enable reaching the net zero emission targets, only efficiency improvements and power from shore are not enough, and there is a need to develop additional low emission technologies not yet on the market. The present study has compiled a large database of specifications for assessing low carbon power production concepts and proposes a methodology that is valuable in screening a large number of commercial and immature technologies.publishedVersio

Sulfur analysis of Bolu-Mengen lignite before and after microbiological treatment using reductive pyrolysis and gas chromatography/mass spectrometry

Atmospheric pressure-temperature programmed reduction coupled with on-line mass spectrometry (AP-TPR/MS) is used for the first time on microbiologically treated coal samples as a technique to monitor the degree of desulfurization of the various sulfur functionalities. The experimental procedure enables the identification of both organic and inorganic sulfur species present in the coal matrix. A better insight in the degradation of the coal matrix and the accompanying processes during the AP-TPR experiment is obtained by a quantitative differentiation of the sulfur. The determination of the sulfur balance for the reductive pyrolysis gives an overview of the side reactions and their relative contribution in the total process. The volatile sulfur species are unambiguously identified using AP-TPR off-line coupled with gas chromatography/mass spectrometry (GC/MS). In this way, fundamental mechanisms and reactions that occur during the reductive pyrolysis could be quantified, explaining the differences in AP-TPR recoveries. Therefore, this study gives a clearer view on the possibilities and limitations of AP-TPR as a technique to monitor sulfur functionalities in coal

Ultrahigh Surface Area Three-Dimensional Porous Graphitic Carbon from Conjugated Polymeric Molecular Framework

Porous graphitic carbon is essential for many applications such as energy storage devices, catalysts, and sorbents. However, current graphitic carbons are limited by low conductivity, low surface area, and ineffective pore structure. Here we report a scalable synthesis of porous graphitic carbons using a conjugated polymeric molecular framework as precursor. The multivalent cross-linker and rigid conjugated framework help to maintain micro- and mesoporous structures, while promoting graphitization during carbonization and chemical activation. The above unique design results in a class of highly graphitic carbons at temperature as low as 800 ??C with record-high surface area (4073 m2 g-1), large pore volume (2.26 cm-3), and hierarchical pore architecture. Such carbons simultaneously exhibit electrical conductivity >3 times more than activated carbons, very high electrochemical activity at high mass loading, and high stability, as demonstrated by supercapacitors and lithium-sulfur batteries with excellent performance. Moreover, the synthesis can be readily tuned to make a broad range of graphitic carbons with desired structures and compositions for many applications.clos