Technological approaches for recovery of petrochemical condensates

Technological approaches for recovery of petrochemical condensates I.V., Veleva1*, M.V., Vanoppen1, C.K., Groot2, A.R.D., Verliefde1 1 Ghent University, Belgium 2 Dow Benelux BV, Terneuzen, The Netherlands * [email protected] Abstract: In the (petro)chemical industry, the importance of steam is highly emphasized as an essential heat transfer and reaction medium, as well as a diluent during crude feed cracking. The variety of process applications of steam lead to the generation of many condensates with different specifics hampering their direct reuse. As part of a project under the scope of the Institute for Sustainable Process Technology (ISPT) and together with several partners (Dow Benelux BV, Terneuzen, Ghent University, Evides Industriewater, KWR Water Research Institute, Kurita, Sitech) this research aims to achieve more efficient production of steam in the (petro)chemical industry by enhancing the recycling of condensates as high quality water and reducing the freshwater intake. In order to reach this goal, a specific research case was initiated at the site of Dow Benelux BV, Terneuzen. Keywords: reuse; condensate; petro(chemical) Introduction The petrochemical production process itself generates condensate streams at elevated temperatures, in which complex organics such as aromatic and oxygenated compounds and emulsion breakers are still present. Due to the nature of these pollutants, such streams are sent to the Waste Water Treatment Plant (WWTP). By strategically by-passing the WWTP and applying an individual treatment on the condensate, a higher energy efficiency, an improved water recovery and lower load to the WWTP can be achieved. Different treatment approaches were preselected; Membrane Distillation (MD) and Membrane Aerated Biofilm Reactor (MABR). MD is a thermally driven (possible low grade waste heat) process operating in the range between 30°C–80°C and applies a microporous hydrophobic membrane for the separation of a vapour from a liquid stream. In order to achieve higher effluent purity, a biological treatment step was also considered. An MABR was selected, where the membranes serve as oxygen supplier (~200mbar) for the treatment and as a support for the development of biofilm. The wastewater surrounding the membranes provides the carbon source needed for the growth of the biomass. Material and Methods Due to the available waste heat in the condensate from Dow Benelux, MD was chosen as a technique for simultaneous water and energy recovery. The influence of key operational conditions on the process efficiency, such as ΔT, Taverage, flow rate and pH in the range from 9.5-13 were studied in a lab scale Direct Contact MD (DCMD), treating a synthetic solution containing main pollutants. The experimental set-up consisted of an acrylic MD module with an active surface area of 163 cm2 and counter current supply of feed and distillate. The temperatures on both sides of the membrane were maintained by two heat exchangers and detected by Resistance Temperature Detector (RTD). The collected data was continuously logged via the program LabView. The values selected for these parameters were chosen to be comparable to a full scale MD configuration and to indicate their influence on the amount and quality of the obtained distillate. Based on a Design of Experiments (DOE) approach, for each studied parameter a high (ΔT = 20°C; Taverage= 60°C, flow rate = 90L/h) and a low level (ΔT = 10°C; Taverage= 40°C, flow rate = 60L/h) were given and different combinations of conditions were tested. To study the biological removal efficiency of the main carbon substances, an MABR pilot with two identical 55L reactors designed by OxyMem, Ireland was installed at the site of Dow. The pilot was operated in series. It was inoculated with sludge from the WWTP of the company and it was initially fed with synthetic mixture gradually replaced by a real condensate stream. In order to assure all necessary elements for a healthy biofilm, macro (N and P) and micronutrients were additionally added. The pilot system was operated for 1.5 years at an HRT of 10h per reactor, which resulted in a feed flow rate to the system of ~130L/day. Results and Conclusions Within the MD experiments it was observed that the higher the Taverage and the flow rate, the flux generated from the system increases. The pH values of the feed solution have an impact on the rejection efficiency of the present organic components due to the influence on their dissociation constants. For example, the main group of the carbon pollutants in the condensate, with pKa around 4.8 at 25oC, were greatly rejected, which could be hypothetically explained by the presence of their unprotonated forms. On the other hand, the most toxic substance in the condensate was less retained at a pH ranging from 9.5 -10.5 as its pKa value is 9.99. This physicochemical characteristic could lower its removal efficiency since partially it would be still present in protonated and more volatile form. On the other hand, when pH values of ~13 were reached in the feed, all constituents were rejected by the membrane from 97.72% to 99.98%. The removal efficiency of the first MABR was mainly dependent on the Total Organic Carbon (TOC) load and the thickness of the biofilm. At lower feed concentrations (e.g. 9 gTOC/day) and optimal biomass growth on the silicon fibers, the first bioreactor was able to remove all main carbon pollutants from 80% up to 99.3%. When very high TOC load of 21 g/day was gradually reached and fed to the system, the operation in series of the MABR pilot reactors was proven beneficial and lead to a final effluent values below detection limits for all identified and known components. The polishing effect of the second reactor was experienced at conditions aiming to achieve the expected on full scale TOC load

Coping with medical threat: An evaluation of the Threatening Medical Situations Inventory (TMSI)

The Dutch Threatening Medical Situations Inventory (TMSI) has been developed to measure cognitive confrontation ('monitoring') and cognitive avoidance ('blunting') within the domain of medical threat. It consists of four scenarios of threatening medical situations, followed by monitoring and blunting alternatives. Its psychometric properties are investigated in students (N = 123), dental (N = 80), HIV - (N = 42) and surgery patients (N = 123). For both scales, internal consistencies proved to be satisfactory. Slight sex and age effects are found. Furthermore, there is a strong situation effect: the scenario highest in controllability shows relatively high monitoring and low blunting scores. Factor structure is stable across samples and shows a good fit with the predicted factor solution. Both scales are found to converge and diverge in a theoretically meaningful manner with a variety of coping style and anxiety measures. In two samples, a sample specific stress scenario was added, but the psychometric qualities of such an extension should not be taken for granted. In an additional sample of working people (N = 48) test-retest reliability proved to be good. It is concluded that the TMSI is a useful instrument for assessing cognitive confrontation and avoidance in medical patients. An English as well as a German translation are available. Copyrigh

Mild desalination demo pilot: New normalization approach to effectively evaluate electrodialysis reversal technology

AbstractKey performance indicators for characterization of nanofiltration performance are well developed, similar key performance indicators for electrodialysis reversal are however underdeveloped. Under the E4Water project Dow Benelux BV and Evides Industriewater BV operate a pilot facility to compare both technologies for their application to mildly desalinate a variety of brackish water streams. Normalized pressure drop, normalized current efficiency and normalized membrane resistance proved to be a useful tool to interpret process performance and to initiate a cleaning procedure if required. The availability of these normalized key performance indicators enables optimization and process monitoring and control of electrodialysis reversal independent of the continuously changing conditions of the feed water

The yield of tertiary survey in patients admitted for observation after trauma

Purpose: Existing literature on trauma tertiary survey (TTS) focusses on multitrauma patients. This study examines the yield of the TTS in trauma patients with minor (AIS 1) or moderate (AIS 2) injury for which immediate hospitalization is not strictly indicated. Method: A single center retrospective cohort study was performed in a level II trauma center. All hospitalized trauma patients with an abbreviate injury score (AIS) of one or two at the primary and secondary survey were included. The primary outcome was defined as any missed injury found during TTS (Type 1). Secondary outcomes were defined as any missed injury found after TTS but during admission (Type 2); overall missed injury rate; mortality and hospital length of stay. Results: Out of 388 included patients, 12 patients (3.1%) had a type 1 missed injury. ISS and alcohol consumption were associated with an increased risk for type 1 missed injuries (resp. OR = 1.4, OR = 5.49). A type 2 missed injury was only found in one patient. This concerned the only case of trauma related mortality. Approximately one out of five patients were admitted for more than 2 days. These patients were significantly older (66 vs. 41 years, p < 0.001), had a higher ISS (4 vs. 3, p = 0.007) and ASA score, 3–4 vs. 1–2 (42.5% vs. 12.6%, p < 0.001). Conclusion: TTS showed a low rate of missed injuries in trauma patients with minor or moderate injury. TTS helped to prevent serious damage in two out of 388 patients (0.5%). ISS and alcohol consumption were associated with finding missed injury during TTS

The effect of hippocampal function, volume and connectivity on posterior cingulate cortex functioning during episodic memory fMRI in mild cognitive impairment

Objectives: Diminished function of the posterior cingulate cortex (PCC) is a typical finding in early Alzheimer’s disease (AD). It is hypothesized that in early stage AD, PCC functioning relates to or reflects hippocampal dysfunction or atrophy. The aim of this study was to examine the relationship between hippocampus function, volume and structural connectivity, and PCC activation during an episodic memory task-related fMRI study in mild cognitive impairment (MCI). Method: MCI patients (n = 27) underwent episodic memory task-related fMRI, 3D-T1w MRI, 2D T2-FLAIR MRI and diffusion tensor imaging. Stepwise linear regression analysis was performed to examine the relationship between PCC activation and hippocampal activation, hippocampal volume and diffusion measures within the cingulum along the hippocampus. Results: We found a significant relationship between PCC and hippocampus activation during successful episodic memory encoding and correct recognition in MCI patients. We found no relationship between the PCC and structural hippocampal predictors. Conclusions: Our results indicate a relationship between PCC and hippocampus activation during episodic memory engagement in MCI. This may suggest that during episodic memory, functional network deterioration is the most important predictor of PCC functioning in MCI. Key Points: • PCC functioning during episodic memory relates to hippocampal functioning in MCI. • PCC functioning during episodic memory does not relate to hippocampal structure in MCI. • Functional network changes are an important predictor of PCC functioning in MCI

Assessing quality of hepato-pancreato-biliary surgery: nationwide benchmarking

Background: Clinical auditing is a powerful tool to evaluate and improve healthcare. Deviations from the expected quality of care are identified by benchmarking the results of individual hospitals using national averages. This study aimed to evaluate the use of quality indicators for benchmarking hepato-pancreato-biliary (HPB) surgery and when outlier hospitals could be identified. Methods: A population-based study used data from two nationwide Dutch HPB audits (DHBA and DPCA) from 2014 to 2021. Sample size calculations determined the threshold (in percentage points) to identify centres as statistical outliers, based on current volume requirements (annual minimum of 20 resections) on a two-year period (2020–2021), covering mortality rate, failure to rescue (FTR), major morbidity rate and textbook/ideal outcome (TO) for minor liver resection (LR), major LR, pancreaticoduodenectomy (PD) and distal pancreatectomy (DP). Results: In total, 10 963 and 7365 patients who underwent liver and pancreatic resection respectively were included. Benchmark and corresponding range of mortality rates were 0.6% (0 −3.2%) and 3.3% (0–16.7%) for minor and major LR, and 2.7% (0–7.0%) and 0.6% (0–4.2%) for PD and DP respectively. FTR rates were 5.4% (0–33.3%), 14.2% (0–100%), 7.5% (1.6%–28.5%) and 3.1% (0–14.9%). For major morbidity rate, corresponding rates were 9.8% (0–20.5%), 28.1% (0–47.1%), 36% (15.8%–58.3%) and 22.3% (5.2%–46.1%). For TO, corresponding rates were 73.6% (61.3%–94.4%), 54.1% (35.3–100), 46.8% (25.3%–59.4%) and 63.3% (30.7%–84.6%). Mortality rate thresholds indicating a significant outlier were 8.6% and 15.4% for minor and major LR and 14.2% and 8.6% for PD and DP. For FTR, these thresholds were 17.9%, 31.6%, 22.9% and 15.0%. For major morbidity rate, these thresholds were 26.1%, 49.7%, 57.9% and 52.9% respectively. For TO, lower thresholds were 52.5%, 32.5%, 25.8% and 41.4% respectively. Higher hospital volumes decrease thresholds to detect outliers. Conclusion: Current event rates and minimum volume requirements per hospital are too low to detect any meaningful between hospital differences in mortality rate and FTR. Major morbidity rate and TO are better candidates to use for benchmarking