Flare Minimization Strategy for Ethylene Plants

Abstract

Flaring is an important but passive method in ethylene plants to protect plant personnel, facilities, and the ambient environment. However, excessive flaring emits huge amounts of CO, CO2, NOx, and hazardous volatile organic compounds (VOCs), which may cause locally transient air pollution problems and negative societal impacts. Flaring may also cause high losses of raw material and energy that could generate more desired products for the industry. Thus, flare minimization has great benefits to environmental, societal, and industrial sustainability. Based on current industrial practices, a general strategy for flare minimization under various ethylene plant events is presented.

Safety‐Considered Proactive Flare Minimization Strategy under Ethylene Plant Upsets

“…4 contains five steps: (i) modeling the CGC section for safety check; (ii) developing a plant-wide DS model; (iii) classifying and quantifying upsets; (iv) performing DS with CGC safety check under various upsets; (v) generating FM strategies based on DS results and analysis. For the modeling part at the first two steps, detailed modeling procedures have been reported [3,4]. Although some modeling works from previous studies are borrowed, the major contribution of this paper should be highlighted: various alternative recycling designs are embedded into the plant-wide dynamic models and various process upsets are introduced into the dynamic model.…”

“…These upsets might cause the generation of off-spec products and usually take a long time (e.g., several minutes or hours) to pull back the products within specifications. Because of the large quantity of generation, those off-spec products have to be sent to the flaring system for destruction, generating high amounts of CO 2 , CO, VOCs (volatile organic compounds), and NO x [2][3][4]. Consequently, the local air quality and community are jeopardized.…”

Managing abnormal operation through process integration and cogeneration systems

“…Xu et al defined some major flaring streams in an ethylene process that will be shown in detail in chapter 3 , which are (Yang, Xu et al 2010):…”

“…They are the stream feed to the 4 th stage compressor, the acetylene reactor outlet and the ethylene product stream as shown in Table 6 summarizes the cause and duration associated with each of the three flared streams used in this case study. We also assumed that total operational hour is 8000 hr/yr Xu 2010, Yang, Xu et al 2010). Here the basic assumption is the co-gen unit has a certain power and heat output.…”

Integrated Ejector‐Based Flare Gas Recovery and On‐Site Desalination of Produced Water in Shale Gas Production

“…In particular, the recovered flare gas can be reused by process heater burners and boiler burners, so that the amount of natural gas purchased by plants can be reduced. Meanwhile, the life span of their flare systems could be extended . FGR units also provide some other intangible benefits.…”