BPMARRK®: Real-time Crude Oil Assay for Monitoring & Optimization of Crude Distillation Units
Sanjay Bhargava
Executive Director (R & D)
Corporate R & D Centre,
Bharat Petroleum Corporation Limited

Ravi Kumar Voolapalli
General Manager
Corporate R & D Centre,
Bharat Petroleum Corporation Limited

Rajeev Kumar
Chief Manager (R & D)
Corporate R & D Centre,
Bharat Petroleum Corporation Limited

Mohammad Muzaffar Ahsan
Senior Manager (R & D)
Corporate R & D Centre,
Bharat Petroleum Corporation Limited

Prashant Parihar
Senior Manager (R & D)
Product & Application Development Centre,
Bharat Petroleum Corporation Limited

Mathew John
Senior Manager (R& D)
Corporate R & D Centre,
Bharat Petroleum Corporation Limited

Srinivasareddy Palle
Senior Research Engineer (R& D)
Corporate R & D Centre,
Bharat Petroleum Corporation Limited

BPMARRK® is a patented technology for predicting detailed refining characteristics of oil within an hour. Refining characteristics of crude oil consist of key information such as distillate yields and their quality, residuepotential, crude oil/blends selection, and hydrogen consumption in Hydroprocessing etc. These characteristics are usually deduced from detailed analysis such as true boiling point distillation, ASTM distillation or detailed molecular and spectroscopic analysis. Although established and widely practiced worldwide, these methods often require significant time, large sample quantity and effort for analysis.

BPMARRK® requires only four physical parameters as input to generate about 500 data information of any unknown crude oil or mix. BPMARRK® is differentiated among any static crude oil database by profiling of unknown crude oils or mix in short time. The methodology has been validated with a large number of crude oils sourced from different origins at laboratory for accuracy. ASTM has recommended this innovation for developing a new standards in ASTM D02.04 K section.

BPMARRK® application for real-time monitoring and optimization of crude distillation units has been validated in five different Indian refineries for real-time monitoring & optimization of plant performance on daily basis. The accuracy of predicted vis-à-vis actual plant distillation yields of the products observed to be within ±1.5 wt%. This has been used by Process Engineers to assist in Refinery Operations (currently implemented in BPCL refineries) for advance planning and regular monitoring, controlling and taking operational decision related to crude oils.

Crude oil is a complex hydrocarbon mixture which is obtained from geological formations beneath the earth. Therefore, quality of crude oils vary considerably from each other and knowing the potential of unknown crude oil /blends in advance can help in making wise business decisions for effective operation of a refinery[1, 2]. The classical evaluation method to identify the potential of crude oils is done through laboratory experiments and analyses, which are lengthy and time consuming processes. Typically, it requires 30-40 liters sample quantity for detailed evaluation and, usually, it takes three to four weeks to complete, and analysis costs over USD 30,000[9-12]. However, the detailed information is typically unavailable during the selection of crude oils. Even during actual refining operations where multiple feeds and blends are processed, the process and operation decisions are sub-optimal[13].

BPMARRK® Crude Oil Assay
In contrast, to get realistic assay for any unknown crude oil parcel or blend of two or three crude oils testing of only four physical parameters is required in laboratory which is then fed into BPMARRK®. This requires small quantity (25 ml) of sample and 45 minutes to analyze the parameters. BPMARRK® is a novel concept for predicting detailed refining characteristics of any unknown crude oil within one hour including device processing time (2 -5 minutes) as depicted in Fig 1.

Figure 1: BPMARRK® Crude Assay

This generates detailed cut-wise data consists of distillation yields including gas composition and characterization of 6-Naphtha BPMARRK®: Real -time Crude Oil Assay for Monitoring & Optimization of Crude Distillation Units cuts (IBP-60, 60-70, 70-90, 90-110, 110-130-140), 4-Kero cuts (140-150, 150-180, 180-200, 200-240), 5-Gas Oil cuts (240-250, 250-290, 290 -310, 310-350, 350-360), 6-VGO cuts (360-370, 370-450, 450-500, 500-525, 525 -550, 550-565), LR (360+) and VR (565+) as depicted in Table 1. BPMARRK® predictions have been validated and accepted by third party for accuracy (Indian and global companies).

Real-Time Monitoring & Optimization of Crude Distillation Units
Real-time monitoring and unit-level optimization of crude distillation units using BPMARRK® has been established. During crude mix change and switch over , the transient value loss can be minimized as data for each tank is available in advance before processing through BPMARRK®. A simple methodology is depicted in Fig 2.

The predictions of plant yields by BPMARRK® has been compared with Actual and conventional database for two months and found closely matching with Actual Plant as shown Fig 3.

Along with distillation yields, other critical properties of the distillate streams especially feed to secondary processing units can also be monitored with the detailed data output generated by BPMARRK®. The present approach enables to maximize non-bituminous crude oil processing during bitumen production

Commercial Implementation
In general, unit-level optimization of crude distillation units wait for laboratory data or crude oil database approximation of crude mix feeding to the columns used during crude switchover. Crude tanks typically changes every 1-3 days depending upon capacity. During each crude switchover , it requires about 6-8 hours for stablization of the plant for optimization based on laboratory data. BPMARRK® provides data in advance even much before feeding to the colulm therefore, the stablization of the plants achieved very fast. This is much helpful when crude mix is drastically changing from low API(high Sulphur) to high API (low sulphur) when distillaiton profiles are signficantly different. The comparison of distillation profile of BPMARRK® and Actual (PLANT) data of one of the BPCL Refineries (crude distillation unit, CDU III) has been depicted in Fig 4. Recently, commerical trial runs conducted in different refineries other than BPCL, the comparison of distillation data of BPMARRK®, Actual Plant, DATABASE & SimDist for two different crude distillation units (AVU- I & II) have been depicted in Fig 5. Commercial trial runs concluded that BPMARRK® plant distillation predictions is superior among all currently used methods like database and SimDist. Implementation of BPMARRK® on daily basis is expected to result in savings up to USD 0.1-2.0/bbl depending upon the current operating practices along with quick stablization of the plant.

Figure 4: Comparison of distillation data of BPMARRK® and Actual Plant for one of the BPCL Refineries (CDU III)

Figure 5: . Comparison of distillation data of BPMARRK®, Actual Plant, DATABASE & SimDist for one of the Indian Refineries (AVU-I & II)

Ranking of Crude Oils
Oil price variations impact the selection process for refinery crude slates. When considering crude and product prices, product demand, refinery configurations and other constraints, the evaluation process can be exhaustive. Software tools are comprehensive and time-consuming to screen and rank crude oils on regular basis[20-23]. To simplify the process, a quick method has been developed and integrated for assessing & ranking of crude oils for making business decisions[4, 14, 15]. The differential in crude oils price (D1) and processing costs (D2) are the most influencing factors that determine crude oil selection. The differential in crude oil prices (also called discount) is influenced by Brent price and crude oil qualities (API, Sulphur). The differential in processing cost is mainly due to cost associated with hydroprocessing and residue evacuation at lower price. Using these basis, net differential (D1-D2) has been estimated. Further, this has been correlated with crude oil properties to estimate the coefficients to develop the model using aforementioned method.

Figure 6 : Ranking of crude oils

Fig 6 depicts the ranking of crude oils vis-à-vis Brent crude price variations for given crude oils e.g., Arab Mix (source: Saudi Arabia), Brega (source: Libya), BH crude (source: India), Saharan Blend (source: Algeria) and Kuwait (source: Kuwait). The crude price variations are due to variation in net differential discounts (due to crude oil qualities and refinery processing cost) for various Brent crude price scenarios. As shown in the Fig 6, the cross over in net margin (ranking of crude oils) is evident due to variation in Brent crude oil price. Thus, measurement of physical properties of oil sample can be used for the ranking of crude oils for net margins at refineries with varying Brent crude pricing. The ranking of crude oils can be then used for selection of appropriate blend of crude oil. With this approach, refiners, crude-oil traders, supply-chain optimizers and crude schedulers can make quick and accurate business decisions.

Hydrogen Consumption in Hydroprocessing
Typically hydroprocessing involves removal of sulphur (S), nitrogen (N) and saturation of aromatics. Characteristics of distillate streams like kerosene, diesel, and VGO obtained from particular crude oil have been considered to estimate the hydrogen consumption. The affecting variables are C/H ratio, aromatics, sulphur, nitrogen and metals etc of that particular distillate streams. Further, to estimate the hydrogen consumption, Carbon (C), Hydrogen (H) and Impurities (I) balance has been considered across the Diesel Hydro-Desulphurization (DHDS) and Hydrocracker Unit (HCU) configuration while upgrading the straight run distillate streams to superior quality distillates[10, 17-19]. Table 2 depicted the illustration of estimation of hydrogen consumption in HCU for VGO derived from Arab Mix crude oil. Similar approach has been opted for estimation of hydrogen consumption in DHDS. The total hydrogen consumption has been considered for both HCU and DHDS configurations. Further, the coefficients have been generated by regression between crude oil properties and total hydrogen consumption (including DHDS and HCU) for development of model using aforementioned method. Further, this has been used to estimate the total hydrogen consumption of Arab Mix-AM (source: Saudia), Kuwait-KW (source: Kuwait) and Kimanis blend (source: Malaysia) crude oils and reported Fig 7. The estimated total hydrogen consumption for AM crude is in agreement with plant data.

BPMARRK® is a rapid tool for generating Crude Oil Assay within an hour to facilitate decisions on real-time basis which has larger impact on overall economics of refining business. This enables fast business and operational decisions related to crude oils and enables Oil Suppliers, International Trades and Supply Chain Optimization for advanced planning, selection of crude oil and Process Engineers for real-time monitoring and unit-level optimization of refinery operations. Indeed BPMARRK® is significantly contributing to reduce human efforts for detailed crude oil characterization at laboratory by saving time. The accuracy of BPMARRK® output is acceptable to the Industry.

BPMARRK® received several recognition at National/International forums viz. (i) Special Commendation Award for "Innovator of the Year - Team", by Petroleum Federation of India (now FIPI) in the year 2014, (ii) Innovation Award 2015/16 - Best Innovation in R & D instituted by Ministry of Petroleum & Natural Gas (MOP & G) and (iii) Jury’s Special Mention Award in 'Digital Modeling' category in Frost & Sullivan's Project Evaluation and Recognition Program 2018.

The authors express their sincere thanks to BPCL management for constant support in validation of the model at refineries and interest in commercialization. And many thanks to Refinery colleagues (Syed Imran Ahmed R & Mr. Rajan VR) for implementation of the work.