Acree Technologies (United States)

Recycling spent lithium-ion batteries (LIBs) is essential for environmental protection and resource conservation. However, effective removal of organic components such as electrolytes and poly(vinylidene fluoride) (PVDF) from cathode materials remains a challenge, which limits recycling of spent LIBs. This systematically investigates the thermal decomposition behaviors of organic components in spent LIBs under a controlled atmosphere and thermal conditions. Four distinct stages of thermal decomposition were identified, among which proper adjustment of stage IV is crucial for complete decomposition of PVDF. Oxygen presence significantly enhances PVDF decomposition via exothermic oxidation. Specifically, the activation energy required for PVDF decomposition under air conditions ranged from 20.1 to 29.6 kJ/mol, substantially lower than the 180.2 to 197.9 kJ/mol observed under Ar, corresponding to an approximately 85% reduction in activation energy. Oxidative pyrolysis decreased fluorine retention in stable fluorinated intermediates, potentially accounting for approximately 50% lower residual fluorine compared to inert conditions. Consequently, oxidative pyrolysis facilitates the transformation of fluorinated intermediates into stable inorganic compounds such as CO2 and CF4, thereby mitigating the environmental risks posed by PFAS precursor retention. These findings support the use of oxygen-rich pyrolysis to enhance organic removal, reduce the PFAS risk, and improve recycling efficiency.

A working group is evaluating the American National Standard, “Criteria for Evaluating Room Noise” (ANSI/ASA S12.2-2019). This presentation will give an overview of our progress and areas of significant proposed change. The goal is to simplify the standard body to match the industry practice of using Noise Criterion curves and A-weighted sound levels as the primary noise level metrics. Less common criteria will be relegated to annexes, with explanations for when it may be appropriate to use these alternate rating systems. Since the beginning of this standard, there has been interest in qualifying the effects of spectral imbalance, temporal variation, and tone prominence. This talk will briefly mention proposals to address these aspects. A procedure for using Noise Criterion curves in one-third octave bands will also be explained. The goal is to solicit feedback from the industry to minimize the challenges associated with implementing this standard.

Publishing sound power data for air handlers involves providing data across millions of variations related to operating conditions and unit configurations. AHRI 260 provides both the measurement and modeling guidelines used by most HVACR companies in the United States. However, many building designers are unfamiliar with the details of how a finite set of measurements taken in accordance with AHRI 260 becomes published sound rate data used to design quiet buildings. A case study based on a real product release is used to clearly define this process.

To broaden and lower the temperature window of the selective non catalytic reduction (SNCR) of nitric oxide (NO), the use of activated ammonia as the reduction agant was examined. An intermittent dielectric barrier dischalge (DBD) was employed to generate activated ammonia from molecular ammonia. Chemical composition was clear by gas analysis at exit of the DBD reactor, it found that the main species of the activate ammonia were H_2 and N_2. By experiments and chemical kinetics simulation, it was clear that H_2 was strongly contributed to enlargement of temperature window ofDeNOx.

To broaden and lower the narrow temperature window of the selective non catalytic reduction (SNCR) of nitric oxide (NO), the use of activated ammonia as the reduction agent was examined A xenon excimer lamp emitting a wavelength of 172 nm (i.e., vacuum ultraviolet; VUV) was employed as the excitation source for molecular ammonia. The effects of reaction temperatures, oxygen concentrations, and NH_3/NO molar ratios (MRs) on NO removal were investigated in a lab-scale plug flow reactor. Temperatures ranged from 500℃ to 850℃. A temperature window enlargement of 150℃ was achieved at the lower boundary of the temperature window. Above 600℃, NO removal was effected by injection of activated ammonia, while around 750℃, conventional SNCR by injection of molecular ammonia was effective. An approximate 80% NO removal was attained at 700℃ with an MR=2.0 and 8.3% O_2.

Interstitial-free steel sheets have been processed using a novel severe plastic deformation technique - continuous frictional angular extrusion (CFAE), in order to produce ultrafine grained structures. The deformation was carried out at room temperature and individual sheet specimens were repeatedly processed to various passes. An overall grain size of 200nm was achieved after 8 passes (or an equivalent total strain of 5.3). The present paper reports the evolution of microstructures during deformation, which were examined and characterized using electron backscatter imaging and high resolution EBSD in a field emission gun SEM. The mechanisms of grain refinement are discussed.