An improved fired heater with air preheating provided by one or more heat pipes. The fired heater may include at least one burner for combusting a fuel stream and an air stream and producing heated exhaust gases; a hot gas flow path and at least one conduit containing a process fluid to be heated by heat transfer from the heated exhaust gases; and an air preheater comprising at least one heat pipe having a first section exposed to the heated exhaust gases and a second section exposed to the air stream, wherein the heat pipe is positioned and arranged to transfer heat from the heated exhaust gases to the air stream, wherein the at least one heat pipe contains a working fluid sealed within the heat pipe, wherein said working fluid transfers heat from the heated exhaust gas to the air stream to be preheated.

The present invention relates to a process for the production of butenes and butadienes from waste plastics feedstocks comprising the steps in this order of: (a) providing a hydrocarbon stream A obtained by hydrotreatment of pyrolysis oil produced from a waste plastics feedstock; (b) optionally providing a hydrocarbon stream B; (c) supplying a feed C comprising a fraction of the hydrocarbon stream A and optionally a fraction of the hydrocarbon stream B to a thermal cracker furnace comprising cracking coil(s); (d) performing a thermal cracking operation in the presence of steam to obtain a cracked hydrocarbon stream D; (e) supplying the cracked hydrocarbon stream D to one or more separation units; (f) performing a separation operation to obtain different streams of chemical products comprising ethylene, propylene, isobutene, 1-butene, 2-butene, 1,2-butadiene, 1,3-butadiene, benzene, styrene, toluene, ethylbenzene and xylenes; wherein in step (d): the coil outlet temperature is >800 and <870° C., preferably >805 and <835° C.; and the weight ratio of steam to feed C is >0.3 and <0.8, preferably >0.3 and <0.5. Such process allows for optimisation of the quantity of waste plastic material that finds its way back into products that are produced as outcome of the process. The higher that quantity is, i.e. the higher the quantity of chemical building blocks that are present in the waste plastic material that are converted to the produced products, the better the sustainability footprint of the process is. The process allows for circular utilisation of plastics.

An ethylene cracking furnace is provided. The ethylene cracking furnace includes at least one radiant section. The at least one radiant section includes bottom burners and/or sidewall burners, and at least one radiant coil arranged in the radiant section. The radiant coil includes at least an upstream pass tube and a downstream pass tube, the upstream pass tube being configured as an inner tube, and the downstream pass tube being configured as an outer tube surrounding the inner tube and having a closed end. The inner tube defines an inner space forming an upstream flow path. A gap defined between the inner tube and the outer tube forms an downstream flow path.

An ethylene cracking furnace is provided. The ethylene cracking furnace includes at least one radiant section. The at least one radiant section includes bottom burners and/or sidewall burners, and at least one radiant coil arranged in the radiant section. The radiant coil includes at least an upstream pass tube and a downstream pass tube, the upstream pass tube being configured as an inner tube, and the downstream pass tube being configured as an outer tube surrounding the inner tube and having a closed end. The inner tube defines an inner space forming an upstream flow path. A gap defined between the inner tube and the outer tube forms an downstream flow path.

The present disclosure provides for thick fins on the surface of coils or tubes in a steam cracking furnace. The fins have a thickness at their base from ¼ to ¾ of the radius of the furnace tube. The fins have grooves or protuberances on not less than about 10% of a major surface. The fins help increase the radiant heat taken up by the tube from the walls and combustion gases in the furnace.

The invention relates a process for removing coke formed during steam-cracking of a hydrocarbon feed. The process includes providing a decoking feed to at least one radiant coil of a steam-cracking furnace under conditions to remove at least a portion of coke from the at least one radiant coil to form a decoking effluent. The decoking effluent is cooled with a liquid quench medium to provide an partially-quenched decoking effluent. The partially-quenched decoking effluent is cooled with a gaseous quench medium to provide a quenched effluent. An apparatus configured to perform such a process is also described.

The invention relates a process for removing coke formed during steam-cracking of a hydrocarbon feed. The process includes providing a decoking feed to at least one radiant coil of a steam-cracking furnace under conditions to remove at least a portion of coke from the at least one radiant coil to form a decoking effluent. The decoking effluent is cooled with a liquid quench medium to provide an partially-quenched decoking effluent. The partially-quenched decoking effluent is cooled with a gaseous quench medium to provide a quenched effluent. An apparatus configured to perform such a process is also described.

The present invention addresses to a system and methodology for evaluating the deposition in tubes of the furnaces of delayed coking unit (DCU) in order to reduce the costs involved with premature shutdowns. With this system, load rankings are obtained, influences of certain loads on processing are evaluated, and additives that reduce deposition are further evaluated. Consequently, the results obtained by such a system allow greater flexibility for the follow-up engineer to optimize his delayed coking unit in order to increase load or increase the unit campaign time, drastically reducing costs in premature shutdowns, or increasing its return by increasing load and shutdowns, since the load is limited by the degree of deposit formation, and that directly affects the wall temperature.

Methods and systems for using temperature measurements taken from a compact insulated skin thermowell to optimize a pyrolysis reaction are provided. In the present systems and methods, the upstream temperature and the upstream pressure of a pyrolysis reactor is measured through an adiabatic restriction in the inlet manifold of a parallel tube assembly to provide an absolute upstream temperature and an upstream pressure. The downstream temperature of the pyrolysis reactor is also measured following an adiabatic restriction to provide an absolute downstream temperature. The downstream pressure is then determined by multiplying the absolute upstream pressure with the quotient of the downstream temperature divided by the upstream temperature as taken to the power of k/k−1, where k is the ratio of fluid specific heat at constant pressure (Cp) to fluid specific heat at constant volume (Cv).

Methods and systems for using temperature measurements taken from a compact insulated skin thermowell to optimize a pyrolysis reaction are provided. In the present systems and methods, the upstream temperature and the upstream pressure of a pyrolysis reactor is measured through an adiabatic restriction in the inlet manifold of a parallel tube assembly to provide an absolute upstream temperature and an upstream pressure. The downstream temperature of the pyrolysis reactor is also measured following an adiabatic restriction to provide an absolute downstream temperature. The downstream pressure is then determined by multiplying the absolute upstream pressure with the quotient of the downstream temperature divided by the upstream temperature as taken to the power of k/k−1, where k is the ratio of fluid specific heat at constant pressure (Cp) to fluid specific heat at constant volume (Cv).