Optimising of vacuum distillation units using surrogate models

Crude oil blending is an important step for the operation of crude distillation systems in the refinery to improve the yield and profitability of the products. The product’s yield and quality are strongly dependent on the properties of the crude oil. However, the products of crude distillation units, especially the vacuum distillation unit (VDU) need to satisfy the yield and quality requirements of the downstream process units in the refinery. Otherwise, the performance of downstream processes will be affected, and loss of profitability in the refinery. Hence, it is important to optimise the performance of the VDU to ensure the optimum operation of VDU. This work covers the process simulation of VDU, surrogate modelling and mathematical optimisation model. The objective of the developed optimisation model is to determine an optimal for maximum high vacuum gas oil (HVGO) yield and minimum total annualised cost (TAC) respectively. To do this, crude oil blending ratio, column temperature, column pressure, stripping steam flowrate, pump-around flowrate in the VDU are optimised. Based on the optimised result, the heavy-light crude blend achieves higher HVGO yield and lower TAC as compared to the heavy-medium crude blend and heavy-medium-light crude blend. The optimised results can provide insight into the optimal process conditions of VDU for the refiners. With this insight, effective operating strategies can be developed to overcome the limitations present in real VDU operations.

PHYSICOCHEMICAL AND ELECTROCHEMICAL METHODS FOR MODIFYING THE PROPERTIES OF DIAMONDS AND ORE PULP COMPONENTS DURING THE SEPARATION OF DIAMOND-BEARING KIMBERLITES

The main deposits of kimberlite ores located in the regions of Western Yakutia are enriched at the ALROSA diamond extraction factories using a similar technology, in which the maximum completeness of extraction and safety of diamond crystals is ensured by the stages of schemes. The bulk of diamond crystals is extracted in the processes of heavy medium, sticky and foam separation, the effectiveness of which is determined by the properties of diamonds, kimberlite minerals and the media separating them. The article presents the results of theoretical and experimental studies carried out by ICEMR RAS together with the largest universities in Russia, scientific and industrial enterprises of ALROSA. It is shown that the use of combined energy methods of destruction and removal of hydrophilizing formations on diamond crystals provides hydrophobization of their surface in the processes of sticky and foam separation. It has been established that the efficiency and economic indicators of the process of dense medium separation of diamond-containing raw materials are due to the stability of the technological properties of the weighting agent of the ferrosilicon medium and the suspension prepared on its basis. The method for modifying the corrosion resistance of ferrosilicon by nitriding its surface has been substantiated and tested. The proposed method makes it possible to create a protective shell on the surface of the granules, preventing their destruction upon contact with corrosive components of the water-air environment. Semi-industrial tests have established the possibility of increasing the extraction of diamonds into concentrates for sticky and foam separation by 4 and 5.2%, respectively. The results of laboratory tests have confirmed the possibility of reducing the corrosion rate of ferrosilicon by 5-6 times in the process of dense medium separation.

POSTPRINT - Application of BDq method to Complex Tropical Mixed Forest Ecosystems in Nigeria

The lack of management practice/silvicultural treatments in the complex tropical mixed forests of Nigeria has led to uncontrolled exploitation of natural forest stands and loss of biodiversity. To sustain production, protection and conservation in the complex tropical mixed stands, this study proposed the application of a selection method – the BDq (B: basal area, D: maximum diameter, q-ratio) method for the management of the stands. Two strata were used as a pilot test: stratum 1 consisted of 15 plots and stratum 2 comprised of 7 plots with a plot area of 0.25 ha. Only trees with diameter at breast (d) ≥ 10.0 cm were considered in this study. Harvest in the BDq method was quantified, by setting B at 20, 25 and 30 m2 ha-1 corresponding to heavy, medium and light-harvesting regimes, respectively. D was set at 65 cm and q-factor was computed for each plot. The results showed that the three BDq regimes (heavy, medium and light) prescribed yielded reasonable felling intensities (FI) derived as the percentage of extracted volume (Vext) and biomass (Wext). The Vext and FI for stratum 1 ranged from 39.94 – 62.30 m3 ha-1 and 11.22 – 18.18 %; and stratum 2 had 30.44 – 51.33 m3 ha-1 and 10.02 – 17.57 %. In the case of biomass, the Wext and FI for stratum 1 ranged from 18.46 – 29.82 tons ha-1 and 9.40 – 15.95 %; stratum 2: 14.16 – 24.82 tons ha-1 and 9.73 – 17.50 %. The finding shows that the application of BDq method to the complex tropical mixed forests in Nigeria would yield an attractive stand.

Study of the Crude oil Properties of Oily seepages found in South Eastern Nigeria.

ASTM D-270 method was applied in obtaining well-head crude oil samples from Awoba 8T (Rivers State), Odidi 23L, and Odidi 46S (Delta State), Eremor 1L (Bayelsa State) and Oily Seepage samples from Ugwueme (Enugu State) and Anam (Anambra State). The0API gravity value of all the samples were 16.190 and 21.470 for Ugwueme seepage and Eremorcrude respectively, 22.470 for Odidi 46s crudeand 44.700, 43.840 and 34.760 for Anam seepage, Awoba 8t and Odidi 23L crudesrespectively, indicating heavy, medium and light crude oils respectively. All the well-head crudes and oily seepage samples studied in this work are onshore samples except Odidi 46s which is an offshore crude sample. The samples were subjected to liquid-liquid extraction using a mixture of n-hexane and dichloromethane (3:1). The extracted fractions were analyzed using GC-FID. The result of the analyses gave polycyclic aromatic hydrocarbons (PAHs) concentrations (mg/kg) of 7106.43 for Awoba 8T crude, 6767.41 for Odidi 23L crude, 5771.20 for Odidi 46S crude, 5191.21 for Eremor crude, 4908.04 for Ugwueme Seepage and 6983.16 for Anam seepage. The predominance of low molecular weight PAHs (LMWPs) over the high molecular weight PAHs (HMWPs) indicate that both the crude oil samples and the oily seepage samples were of Petrogenic Source. However, various ratios were obtained to identify the possible source of PAHs in the crude oil and seepage samples. Mixed sources of pyrogenic and petrogenic PAHs were also discovered with evidence of „pyrolytic‟ input which may suggest some geothermal-mediated processes.

REVIEW OF BUILDING MAINTENANCE AND MAINTENANCE MANAGEMENT SYSTEM AT THE SUNAN HOTEL SOLO

<p>The purpose of this study is to find out how the building repair and maintenance management system of the building on the hotel and to know how the repairment and maintenance of the building on the hotel, and to review the condition of the existing damage of structural components, architecture, mechanical and electrical, exterior space and housekeeping categorized in heavy, medium and light damage. This study's methodology is qualitative and quantitative scripted research with observation methods, bibliography, qualitative, and documentation. The population and samples used are all Engineering Department employees because there are only fewer than 100 people. The results of the review of the data obtained are data on the Engineering Department's Organization Structure, Employee Job Description, and Workflow. In the implementation of repair and maintenance, 76% of employees already carried out, the largest massive damage review for the field of housekeeping is polishing granite marble 39.23 %. For the largest moderate damage is on the outer space field 30.85 %, then the largest minor damage is in the field of architecture of 58.71 %. These results serve as a guide in the planning of the annual work program.</p>

Watching television films and time management skill of students as predictors of achievement motivation of primary school students: the case of Woldia Town

The study attempted to examine students extent of Watching TV films and drama. The study followed mainly a correlation design and was conducted on 306 students drawn from three randomly selected primary schools in Woldia town,. Data on respondents’ were collected using close ended questionnaires. Pearson correlation was used to see the relation between variables, the result showed that the independent variables do have a significant relationship with the dependent variable except in low TV films and drama viewers. Extent of Watching TV films and drama of students in the study area were 23.2 % Heavy TV films and drama Viewers/above 3.5 hrs per day/,33.6 % Medium TV films and drama Viewers /between 2.5 up to 3.5 hrs per day and 43.14 %low TV films Viewer/below 2.5 hrs per day/. Results of the multiple linear regression revealed that Watching TV films and Time management skill of students interaction taken together explained 18.6%,11.5% and 3.5% in heavy ,medium and low TV films and dramas Viewers of the variance in achievement Motivation. Thus, based on the findings it can be concluded that Watching TV films and drama and time management skills of students are important precursors of achievement Motivation. Following the conclusion several recommendations were forwarded

Plant Species Diversity and Degree of Homogeneity after the 2010 Eruption of Mount Merapi, Indonesia

The eruption in 2010 of Merapi Mount changed the diversity of plant species. The objective of this research was to investigate the diversity of plant species on Mount Merapi National Park (MMNP). The sampling area was divided into three different levels of damage (heavy, medium, and mirror). The research was conducted by using line-transect and quadrat method. We were conducted using line-transect and quadrat method. The research showed that Acacia decurrens has the highest Important Value Index (IVI) at the heavy damage area of Cangkringan Resort (CR) and Kemalang Resort (KR) as well as in mirror damage area of Selo Resort (SR). The most important species at medium damage area of Dukun Resort (DR) were Albizia lopantha and Pinus merkusii. The pioneer species at Non-Cover Area (NCA) among others were Trema cannabina, Pityrogramma calomelanos, Imperata cylindrical, Buddleja asiatica, Anaphalis javanica. Eupatorium riparium were the most important species of herb in all four locations based on SIMPER, but it was not dominant in NCA. The homogeneity of plant in Cangkringan Resort and Selo Resort (C < D < E) were normally distributed, whereas NCA, DR, and KR (E ≥ D) were homogeneous. Analysis of non-metric multidimensional scaling and value of ANOSIM (RANOSIM =0.69; p = 0.0001) demonstrated that all site locations have significance differences. This research was not only focusing on survey of vegetation diversity, but also frequency class distribution. Through this study of frequency of species provides a database for conservation biodiversity and restoration program.