Central control technology helps China’s top 500 chemical enterprises enhance efficiency by tapping into their potential

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This post was last edited by Li Hui@SUPCON on 2022-9-29 at 10:06. As organic derivatives of ammonia, fatty amines are important raw materials for the synthesis of many chemical products, and they are widely used in various industries such as pesticides, pharmaceuticals, coatings, dyes, catalysts, curing agents, new energy materials, cosmetics, food additives, fertilizer release controllers, and preservatives. To address issues such as fluctuations in product quality and high workload for operators, the company decided to introduce APC technology first in its 30,000 tons per year ethylamine production facility, in order to enhance automation levels, improve product quality, and achieve production goals that feature safety, control, energy savings, and reduced consumption ； At the same time, it is hoped that through the successful application of the APC system in the ethylamine plant, a benchmark and reference can be provided for other plants. Working together to advance optimized control, the 30,000 tons/year ethylamine plant includes synthesis and separation processes, and is characterized by a long process flow, numerous pieces of equipment, and multiple cycles of materials – making it a typical multivariable production process ； During production operations, it is necessary to overcome the strong coupling between process variables in order to achieve stable control of process parameters, as well as to maintain material and energy balance both between different processes and within each process. Process operations based solely on manual experience make it difficult to ensure the stable operation of the equipment as well as energy savings and reduced consumption. Based on the above analysis, Zhongkong Technology takes into account the process characteristics of the ethylamine production unit as well as its process control requirements. By employing multivariable model predictive control along with intelligent control strategies such as expert control, it achieves multi-objective optimization and coordinated control of the unit, enhances the stability of its operation, reduces the workload on operators, ensures safety during the production process, and lowers energy consumption through optimization of operational parameters. Seven controllers ensure the stable operation of the device. Model predictive control is an advanced model-based control strategy that features a predictive model, rolling optimization, and feedback correction, and is suitable for addressing the coordinated control challenges of complex multi-variable processes. To meet the requirements for optimized control of the 30,000 tons/year ethylamine plant, Zhongkong Technology designed seven controllers, including: a synthesis reaction controller, an ammonia tower controller, a monoethylamine tower controller, a diethylamine tower controller, a diethylamine purification tower controller, a triethylamine tower controller, and a dehydration tower controller. Through these seven controllers, the stable and optimized operation of the ethylamine plant is achieved. Six expert control strategies enable intelligent control. Intelligent control is an advanced control strategy that employs anthropomorphic thinking methods, planning, and decision-making, guided by knowledge engineering, and features self-learning, adaptability, and self-organization capabilities. In the 30,000 tons/year ethylamine plant, the central control technology has designed six expert intelligent control strategies. Depending on the conditions at the site, in order to achieve optimal control under various operating conditions, the control strategy is rapidly updated through expert control combined with model predictive control, thereby ensuring the safe and stable operation of the equipment. For example, the control of the inorganic phase level and lateral liquid level in the stratifier, as well as the control of the temperature in the triethylamine tower and the liquid level in the reflux tank, can all employ different control strategies depending on the operating conditions ； To ensure the safety of equipment production and product quality, intelligent control is implemented for some vent valves and product extraction valves. For example: expert intelligent controllers for reactor pressure, monoethylamine column pressure, temperature of the monoethylamine purification column, and temperature of the diethylamine purification column. Comparison chart before and after the implementation of the APC: significant improvements in efficiency and reduced energy consumption. After the adoption of the APC system, the operation rate of the controllers reached 98.8%, while the degree of automatic control of the equipment increased to 96.2% ； The operation frequency has been reduced from 4,656 times per 5 days to 2 times per 5 days, **reducing the workload on the operators ； On the basis of stable and optimized operation of the equipment, the steam consumption per unit of product produced was reduced by more than 1.7%, achieving energy savings and reduced consumption. The percentage reduction in loop variance before and after operation. Meanwhile, the value of the advanced control system for the ethylamine plant has been widely recognized by customers. Subsequently, the company chose to cooperate with Zhongkong Technology once again and signed contracts for advanced control systems for 5 sets of facilities, including those for isopropylamine, ethylamine (Phase 3), butylamine, n-propylamine, and acetates ； By fostering mutual trust and achieving mutual benefits, both parties work together to help this enterprise move toward a more efficient, precise, and intelligent production model, thereby paving the way for the domestic organic amine industry to explore a new path characterized by safe production, environmental sustainability, energy savings, improved quality, and cost reduction.