Integrated Process and Integrated System for Obtaining Chemicals From Renewable Organic Material by Hydrotreatment

Abstract

Provided is an integrated process for obtaining chemicals from renewable organic material by hydrotreatment including the steps of feeding the renewable organic material into at least one pre-treatment unit for removing any material not suitable as feedstock for subsequent hydrotreatment, feeding the pre-treated organic material from the at least one pre-treatment unit to at least one hydrotreatment unit for providing gas-oil like hydrocarbons from the pre-treated organic material in the presence of hydrogen and a catalyst, feeding the gas-oil like hydrocarbons from the at least one hydrotreatment unit into at least one steam cracker furnace unit for thermal cracking for providing a cracked product mixture; and feeding the cracked product mixture into at least one steam cracker fractionation unit for separating the cracked product mixture into high value chemicals in particular ethylene, propylene, butadiene and BTX aromatics, hydrogen, fuel gas and fuel oil.

Claims

1. An integrated process for obtaining chemicals from renewable organic material by hydrotreatment, comprising the steps of: feeding the renewable organic material into at least one pre-treatment unit for removing any material not suitable as feedstock for subsequent hydrotreatment, feeding the pre-treated organic material from the at least one pre-treatment unit to at least one hydrotreatment unit for providing gas-oil like hydrocarbons from the pre-treated organic material in the presence of hydrogen and a catalyst, feeding the gas-oil like hydrocarbons from the at least one hydrotreatment unit into at least one steam cracker furnace unit for thermal cracking for providing a cracked product mixture; and feeding the cracked product mixture into at least one steam cracker fractionation unit for separating the cracked product mixture into high value chemicals, in particular ethylene, propylene, butadiene and BTX aromatics, hydrogen, fuel gas and fuel oil, wherein at least part of the hydrogen from the at least one steam cracker fractionation unit is recycled back to the at least one hydrotreatment unit wherein the fuel gas from the at least one steam cracker fractionation unit is fed to the at least one steam cracker furnace unit, and wherein the fuel oil from the at least one steam cracker fractionation unit is fed to at least one power plant.

2. The process according to claim 1, wherein the renewable organic material are plant based fats and oils, in particular vegetable oil, tall oil, animal based fats and oils and/or fish oil.

3. The process according to claim 1, wherein the material removed from the at least one pre-treatment unit is fed as fuel supply to the at least one power plant.

4. The process according to claim 1, wherein any excess hydrogen which has not been consumed during hydrotreatment of the organic material in the at least one hydrotreatment unit is fed into the at least one steam cracker fractionation unit.

5. The process according to claim 1, wherein at least part of the hydrogen required for hydrotreatment of the pre-treated organic material in the hydrotreatment unit is provided by at least one electrolyser using water released during the hydrotreatment of the organic material in the at least one hydrotreatment unit.

6. The process according to claim 5, wherein in addition to the water released during the hydrotreatment of the organic material in the at least one hydrotreatment unit further water from an external source is introduced into the at least one electrolyser.

7. The process according to claim 5, wherein the oxygen released by the at least one electrolyser is at least partially transferred to the at least one power plant.

8. The process according to claim 1, wherein at least part of the energy required for the at least one pre-treatment unit, for the at least one hydrotreatment unit and for the at least one steam cracker fractionation unit is obtained from the at least one power plant

9. The process according to claim 1, wherein CO.sub.2 released from the at least one steam cracker furnace unit and CO.sub.2 released from the at least one power plant is at least partially fed to at least one CO.sub.2 capture unit.

10. An integrated system for obtaining chemicals from renewable organic material by hydrotreatment in a process according to claim 1 comprising: at least one pre-treatment unit for removing any material from the renewable organic material that is not suitable as feedstock for subsequent hydrotreatment; at least one hydrotreatment unit arranged downstream from the at least one pre-treatment unit for providing gas-oil like hydrocarbons from the pre-treated organic material in the presence of hydrogen and a catalyst by hydrotreatment; at least one steam cracker furnace unit; arranged downstream from the at least one hydrotreatment unit for thermal cracking for providing a cracked product mixture; at least one steam cracker fractionation unit arranged downstream from the at least one steam cracker furnace unit for separating the cracked product mixture into high value chemicals, in particular ethylene, propylene, butadiene and BTX aromatics, hydrogen, fuel gas and fuel oil; and at least one power plant for providing energy to the at least one pre-treatment unit, the at least one hydrotreatment unit and for the at least one steam cracker fractionation unit, wherein the at least one steam cracker fractionation unit is in fluid connection to the at least one hydrotreatment unit for recycling at least part of the hydrogen obtained during separation of the cracked product mixture in the steam cracking fractionation unit to the hydrotreatment unit, the at least one steam cracker furnace unit for feeding the fuel gas obtained during separation of the cracked product mixture in the steam cracking fractionation unit to the steam cracker furnace unit, and the at least one power plant for feeding the fuel oil obtained during separation of the cracked product mixture in the steam cracking fractionation unit to the power plant.

11. The system according to claim 10, further comprising at least one electrolyser in fluid connection to the at least one hydrotreatment unit, a. wherein the at least one electrolyser receives water from the at least one hydrotreatment unit released during the hydrotreatment of the renewable organic material, and b. wherein the at least one electrolyser provides at least part of the hydrogen to the at least one hydrotreatment unit for the hydrotreatment of the renewable organic material.

12. The system according to claim 10, wherein the at least one power plant is in fluid connection the to the at least one pre-treatment unit for feeding the material removed from the at least one pre-treatment unit as fuel supply to at least one power plant.

13. The system according to claim 10, further comprising at least one CO.sub.2 capture unit for capturing CO.sub.2released from the at least one steam cracker furnace unit; and/or for capturing CO.sub.2 released from the at least one power plant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0137] The solution is further described in more detail by means of examples with reference to the figures.

[0138] FIG. 1 shows a scheme of a first embodiment of the present process and system.

[0139] FIG. 2 shows a scheme of a second embodiment of the present process and system.

[0140] FIG. 3 shows the scheme of FIG. 2 illustrating the mass flows and utility flows.

DESCRIPTION OF THE INVENTION

[0141] FIG. 1 shows a schematic overview of a first variant of the present process.

[0142] Vegetable oil 101 is introduced into a pre-treatment unit 102, where any material not suitable as hydrotreatment feedstock is removed. Such material can include metals, phospholipids or heavy pitch or gums.

[0143] Energy required by pre-treatment unit 102 is supplied from integrated power plant (or steam boiler) 115 that uses biogenic material, including residues from said pre-treatment steps, as fuel.

[0144] The pre-treated bio-oil is fed into a hydrotreatment unit (HDT, 103), where hydrogen and energy is added to catalytically remove oxygen and saturate olefinic double bonds. Energy need of hydrotreatment is covered by steam coming from same power plant 115 that supplies energy for pre-treatment.

[0145] The main product of the hydrotreatment, renewable gasoil-like hydrocarbons 107, is fed into steam cracking furnace 108 for thermal cracking. Steam cracking furnace cracks long-chain, paraffinic hydrocarbons into a mixture of products that are separated from each other in fractionation part 110 of the steam cracker.

[0146] Energy for steam cracking furnace 108 is supplied by fuel gas 113 that is resulting from steam cracking fractionation reaction 110. Energy for fractionation 110 is supplied partly from recovering the heat from steam cracking product and partly from the same steam boiler 115 that supplies steam to pre-treatment and hydrotreatment. Renewable fuel oil 114, also a product of steam cracking fractionation 110 of renewable hydrocarbons, is used to complement the fuel supply in the power plant or steam boiler 115.

[0147] Hydrogen 112 is separated from cracker fuel gas and hydrotreatment off-gas with a PSA unit (not shown) and returned back to hydrotreatment 103.

[0148] The main chemical products 111 of steam cracking fractionation 110 of renewable hydrocarbons are ethylene, propylene, butadiene and BTX aromatics (Benzene, Toluene, Xylene). All these products have a material application (instead of fuel) and are main target and primary product of this concept.

[0149] Any other hydrocarbon product 123, besides fuel gas 113 and fuel oil 114 and chemical products 111, will be re-directed to steam cracking furnaces for further cracking and conversion into chemicals and renewable fuel gas, fuel oil and hydrogen.

[0150] The process variant illustrated in FIG. 2 includes additional steps and elements.

[0151] Since the hydrogen 112 from the steam cracker fractionation 110 is not enough to satisfy the needs of hydrotreatment unit 103, the hydrogen supply is complemented with an electrolyser 105 that uses renewable electricity and water 104 from bio-oil hydrotreatment 103 to produce hydrogen 106 and oxygen 122.

[0152] The oxygen product of the electrolyser 122 can be used in power plant/steam boiler 115 to enhance combustion of pre-treatment rejects and renewable fuel oil.

[0153] Replacement of air with oxygen in the power plant 115 will also concentrate carbon dioxide in the flue gas 119 from the power plant, making it more energy and capital efficient to capture that CO.sub.2 in case a negative carbon footprint is desired for the concept. In case a CO.sub.2 capture unit 120 is included, also flue gases 118 from steam cracking furnace 108 are processed in the CO.sub.2 capture unit 120. Carbon capture unit 120 consists of an amine absorber and a compressor unit for CO.sub.2 liquefaction.

[0154] Hydrotreatment process 103 typically requires a slight excess of hydrogen, and that hydrogen excess 121 is returned in the steam cracker, along with any light hydrocarbons resulting from possible side-reaction of hydrotreatment, into steam cracker for further utilisation.

[0155] The resulting scheme utilises existing steam cracker assets for production of renewable hydrocarbon. Only renewable energy and fuels are used to power the process, with an option to capture biogenic CO.sub.2 for achieving negative CO.sub.2 footprint for the products.

Example

[0156] Typical composition of crude tall oil is presented in Anthonykutty, J. M., Linnekoski, J., Harlin, A., and Lehtonen, J., Hydrotreating reactions of tall oils over commercial NiMo catalyst, Energy Science & Engineering, 2015. 3(4), 286-299).

[0157] The fraction consisting of neutrals, making 23% of the crude tall oil, are removed in pre-treatment step before hydrotreatment unit. The remaining 77% are hydrotreated for removal of oxygen and saturation of any double bonds.

[0158] Subjecting the hydrocarbon product mixture to steam cracking in a conventional liquid cracking furnace results in product mixture similar to one given by steam cracking of a paraffinic hydrocracker residue (see: Ullmann's ethylene page 17-HCR cracking yields).

[0159] 5 In the following tables 1 and 2 mass flows and utility flows of the process according to the solution are provided with reference to the scheme of FIG. 3.

[0160] The results show that the process according to the solution allows for obtaining high value chemicals that can be used for polymer synthesis from renewable organic material with 10 reduced CO.sub.2 emission and reduced overall costs.

TABLE-US-00001 TABLE 1 Mass flows Mass flows 7 8 3 4 5 6 Hydro- Hydro- 9 10 1 2 Tall Hydro- HC Reaction gen gen HC Fuel CTO Pitch Oil gen product water purge recycle recycle gas CTO 1000 Tall oil pitch 230 Tall oil 770 Hydrogen 28 2.5 8.5 Hydrocarbons 705 174.3 Water 96 Fuel gas 97.4 High value chemicals Fuel oil Oxygen CO2 Mass flows 11 13 14 15 16 17 High 12 Electro- Electro- Additional Steam Power 18 value Fuel lyser lyser water cracker plant Captured chemicals Oil Hydrogen oxygen input CO2 CO2 CO2 CTO Tall oil pitch Tall oil Hydrogen 19.2 Hydrocarbons Water 77 Fuel gas High value 531.7 chemicals Fuel oil 69.9 Oxygen 154 CO2 267.9 1041.3 1309.2

TABLE-US-00002 TABLE 2 Utility flows Utility flows 1 . . . 4 5 Power plant Eletrolyser steam electricity Steam (40 barg) 6425 Electricity kW 897 Steam enthalpy 2.4 MJ/kg Fuel gas LHV 50 MJ/kg Fuel oil LHV 39.8 MJ/kg Tall oil pitch LHV 40.6 MJ/kg

[0161] Finally the amount biogenic CO.sub.2 can be calculated from incinerated fuels using conversion factors of 2.75 kgCO.sub.2/tonne for fuel gas, 3.38 kgCO.sub.2/tonne for fuel oil and 3.5 kgCO.sub.2/tonne for tall oil pitch.

TABLE-US-00003 In Out CTO 1000 kg Electricity 897 kWh Water 77 kg Chemicals 532 kg CO2 (biogenic, captured) 1309 kg

[0162] From the overall mass balance above it can be concluded that both the inputs and outputs of the concept are non-fossil and the fossil carbon footprint of the produced chemicals is zero or negative depending on the further use of the captured CO.sub.2.