HEAT RECOVERY IN DECOMPOSITION OF PARAFFIN HYDROCARBONS Russian patent published in 2019 - IPC C07C5/333 

FIELD: technological processes.

SUBSTANCE: invention relates to processes for the production of olefinic hydrocarbons. Invention relates to a method for producing olefinic hydrocarbons by dehydrating the corresponding paraffin hydrocarbons in a fluidized bed of an aluminum-chromium catalyst circulating in a reactor-regenerator system, including the preparation of a mixture of liquid raw materials from fresh and recycled paraffinic hydrocarbon streams, its evaporation the heat exchanger-evaporator 3, heating the resulting vapors due to the heat of the contact gas of dehydrogenation, cooling the contact gas in the surface heat exchangers and further cooling and cleaning of the contact gas by contacting with irrigating water in two-stage scrubber 22, divided by deaf overflow plate 23 to first stage of contacting 24 in the lower part of scrubber 22 with the lower water circulation circuit and on second contacting stage 25 in its upper part with the upper water circulation circuit having heat exchanger-cooler 26 of circulating water, the subsequent compression of the cooled contact gas, condensation and separation from hydrocarbon condensate by rectification of the fraction of unreacted paraffin hydrocarbons with its recycling to dehydrogenation and fractions of the resulting olefinic hydrocarbons. Cooling and cleaning of the contact gas in first contacting stage 24 of scrubber 22 is carried out in the mode of quenching the contact gas to a temperature of 62.5–74.0 °C by evaporation of 3.3–12.04 % water, circulating in first contacting stage 24 with a multiplicity of circulation constituting 1.06–4.77 t/t of supplied contact gas, and in second contacting stage 25 – with a ratio of water circulation in second contacting stage 25 constituting 2.7–4.8 t/t of contact gas, in the mode of condensation of water vapor, coming from the contact gas through blind overflow plate 23 from first contacting stage 24 of scrubber 22, with simultaneous return of excess water from the cube of second contacting stage 25 of scrubber 22 to first contacting stage 24, while also circulating water of first contacting stage 24 is sent as a coolant to additional heat exchanger-heater 2 of liquid raw materials and then returned chilled to irrigate first contacting stage 24 or the circulating water of second contacting stage 25 of scrubber 22 is sent as a coolant to heat exchanger-evaporator 3 to evaporate the liquid raw material or to heat it, the subsequent evaporation and heating of the obtained vapor of paraffin hydrocarbons, and then returned cooled to second contacting stage 25 of scrubber 22, while the temperature of the contact gas at the entrance to scrubber 22 is reduced to 160–250 °C, and at the exit of scrubber – up to 24–40 °C, and as first contacting stage 24 using a column with failed plates, working in foam mode with countercurrent movement of irrigating water and contact gas through the holes of the plates, or a column with non-charging plates with an overflow device operating in foam mode during the cross-movement of irrigating water and contact gas, or a Venturi scrubber containing blender tube 37 and a droplet separator in the bottom part of scrubber 22.

EFFECT: increase in the degree of purification of contact gas from catalyst dust and heavy hydrocarbons in the scrubber for cooling and cleaning of contact gas of dehydrogenation; reducing the temperature of the contact gas at the inlet and the outlet of the scrubber; production of hot water suitable for use as a heat carrier in surface heat exchangers of technological schemes for a dehydrogenation unit; a significant decrease in water circulation in the contacting stages of the scrubber; possibility of increasing the capacity of the plant based on the use of existing equipment.

21 cl, 8 ex, 4 tbl, 4 dwg