Method for distributing hydrogen and carbon emission in evaluation of carbon footprint of hydrocracking product

Abstract

The invention provides a method for distributing hydrogen and carbon emission in evaluation of carbon footprints of hydrocracking products, and relates to the technical field of evaluation of carbon footprints of products in the oil refining industry. The invention relates to a hydrogen carbon emission distribution method in hydrocracking product carbon footprint evaluation, which comprises the following steps of: comparing a raw material with a hydrocracking product carbon hydrogen ratio to obtain chemical hydrogen consumption of each product, and further distributing the carbon emission of hydrogen in a hydrocracking process according to the chemical hydrogen consumption and the carbon footprint of the hydrogen. Therefore, the distribution of the carbon emission of the auxiliary material hydrogen in the carbon footprint of each product in the evaluation of the carbon footprint of the hydrocracking product is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon footprint evaluation of oil refining industry products, and in particular to a method for distributing hydrogen carbon emissions in carbon footprint evaluation of hydrocracking products. Background Art

[0002] The carbon footprint of a product is calculated according to the life cycle method to calculate the greenhouse gas emissions generated by the product during the stages of raw material acquisition, transportation, production, and use. When evaluating the carbon footprint of petrochemical products, it is necessary to allocate the carbon emissions of each link in the production process to the product, including the auxiliary materials used in the production process. Hydrocracking is an important processing technology in the oil refining industry. This process is to crack large molecular hydrocarbons into small molecular products through catalysts under hydrogen, high temperature and high pressure conditions.

[0003] In the cracking reaction, hydrogen is used to fill the free radical vacancies after the breaking of CC bonds and is an important auxiliary material. At the same time, the carbon emissions from the hydrogen production process are huge; therefore, when evaluating the carbon footprint of the hydrocracking unit products, the carbon emissions from the hydrogen production process should be included in the product in the form of hydrogen as an auxiliary material.

[0004] The current standards guiding product carbon footprint assessment - "PAS2050 Specification for Greenhouse Gas Emissions Assessment of Goods and Services during their Life Cycle" and "ISO14067" do not involve the allocation of hydrogen carbon emissions to each product in the carbon footprint assessment of hydrocracking unit products.

[0005] In view of this, the present invention is proposed to address the problem of allocating hydrogen carbon emissions in the hydrocracking process to the carbon footprint of each product, which has not been raised in the existing product carbon footprint evaluation standards. This application calculates the hydrogen component change (chemical hydrogen consumption) of the carbon component before and after the cracking reaction according to the different reduction extents of the carbon-hydrogen ratio of different products relative to the raw materials, and then allocates the hydrogen carbon emissions in the hydrocracking process based on the chemical hydrogen consumption and the hydrogen carbon footprint. Summary of the invention

[0006] The purpose of the present invention is to provide a method for allocating hydrogen carbon emissions to products when evaluating the carbon footprint of hydrocracking unit products. This method makes the evaluation of the allocation of hydrogen, an auxiliary material in the hydrocracking process, to the carbon footprint of each product more accurate based on the chemical hydrogen consumption and the hydrogen carbon footprint.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0008] Calculate the carbon component mass of the product based on the carbon-hydrogen ratio of the hydrocracking product;

[0009] The raw material mass of the corresponding product carbon component is calculated based on the raw material carbon-hydrogen ratio, and the product hydrogen consumption is calculated based on the product mass and the raw material mass;

[0010] Based on the hydrogen consumption of the products, the carbon emissions of hydrogen are allocated to each product.

[0011] Furthermore, for the petroleum fractions with an average relative molecular mass of 70-300 and a medium average boiling point of 300-616K, the carbon-hydrogen ratio is calculated from the medium average boiling point and relative density; for the petroleum fractions with an average relative molecular mass of 300-600 and a medium average boiling point of 616-811K, the carbon-hydrogen ratio is calculated from the medium average boiling point, relative density and Huang's factor.

[0012] Furthermore, the average relative molecular weight of the petroleum fraction is calculated from the average boiling point and the relative density; the average boiling point is calculated from the volume average boiling point and the average boiling point correction parameter; the average boiling point correction parameter is calculated from the volume average boiling point and the slope of the Englert distillation curve.

[0013] Furthermore, the mass of the product carbon component is calculated from the product output and the product carbon-hydrogen ratio; the mass of the raw material corresponding to the product carbon component is calculated from the mass of the product carbon component and the raw material carbon-hydrogen ratio.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the method obtains the change in hydrogen component of the carbon component before and after the cracking reaction, that is, the chemical hydrogen consumption of each product, by comparing the carbon-hydrogen ratio of the raw material and the carbon-hydrogen ratio of the product after hydrocracking, and then distributes the hydrogen carbon emissions to each product based on the chemical hydrogen consumption and the hydrogen carbon footprint, thereby making the distribution of hydrogen carbon emissions in each product more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to illustrate the specific implementation manner of the present invention or the technical solution in the prior art, the drawings required for use in the specific implementation manner or the description of the prior art will be briefly introduced below.

[0016] Figure 1 This is a process flow chart of the reaction part of the hydrocracking unit in this application.

[0017] Depend on Figure 1 It can be seen that the reaction part of the hydrocracking unit in this application is composed of systems such as raw material pretreatment, reaction feed heating furnace, hydrogenation reaction, new hydrogen compressor, circulating hydrogen compressor, and circulating hydrogen desulfurization.

[0018] It should be noted that after the raw oil (vacuum wax oil) enters the hydrocracking unit, it is pressurized by the raw material booster pump and enters the reaction system after reflux heat exchange with the distillation tower. The hydrogen from the hydrogen pipeline is pressurized by the new hydrogen compressor and then mixed with the circulating hydrogen from the circulating hydrogen compressor and the pressurized raw oil in turn. The mixed hydrogen oil is heated by the reaction feed heating furnace and enters the reactor. The reaction products are separated to obtain circulating hydrogen and low-fraction oil. The circulating hydrogen enters the desulfurization tower for treatment and then returns to the reactor. The reaction products are divided into cold low-fraction oil and hot low-fraction oil, which are separated into dry gas, liquefied gas, naphtha, jet fuel, diesel, tail oil and other fractions downstream. DETAILED DESCRIPTION

[0019] The technical terms of this application text and each calculation formula can be expressed using formula symbols, and the specific meanings of the formula symbols are as follows:

[0020] CH p,i —Product carbon-hydrogen ratio;

[0021] C p,i —Product i carbon component mass (product i carbon component flow);

[0022] CH F —C / H ratio of raw materials;

[0023] F i —Quality of carbon component of raw material of product i;

[0024] F p,i —Product i output (product i flow);

[0025] △H p,i —Hydrogen consumption of product i;

[0026] t v — volume-average boiling points of petroleum fractions;

[0027] △me—mean boiling point correction parameter;

[0028] t me —Medium average boiling point;

[0029] S—slope of the distillation curve.

[0030] Figure 1 This is a process flow chart of the reaction part of the hydrocracking unit in this application.

[0031] Depend on Figure 1 It can be seen that the reaction part of the hydrocracking unit in this application is composed of systems such as raw material pretreatment, reaction feed heating furnace, hydrogenation reaction, new hydrogen compressor, circulating hydrogen compressor, and circulating hydrogen desulfurization.

[0032] It should be noted that after the raw oil (vacuum wax oil) enters the hydrocracking unit, it is pressurized by the raw material booster pump and enters the reaction system after reflux heat exchange with the distillation tower. The hydrogen from the hydrogen pipeline is pressurized by the new hydrogen compressor and then mixed with the circulating hydrogen from the circulating hydrogen compressor and the pressurized raw oil in turn. The mixed hydrogen oil is heated by the reaction feed heating furnace and enters the reactor. The reaction products are separated to obtain circulating hydrogen and low-fraction oil. The circulating hydrogen enters the desulfurization tower for treatment and then returns to the reactor. The reaction products are divided into cold low-fraction oil and hot low-fraction oil, which are separated into dry gas, liquefied gas, naphtha, jet fuel, diesel, tail oil and other fractions downstream.

[0033] The carbon-hydrogen ratio of each product obtained by the hydrocracking unit is lower than that of the raw material, which requires a certain amount of hydrogen to be consumed in the production process for chemical reaction, i.e. chemical hydrogen consumption. Chemical hydrogen consumption mainly fills the vacant position after the CC bond of the raw hydrocarbon is broken, and is an auxiliary material for the cracking reaction.

[0034] The present invention provides a method for allocating hydrogen carbon emissions in carbon footprint evaluation of hydrocracking products. The method is based on the carbon-hydrogen ratio (CH F ) and product carbon-hydrogen ratio (CH p,i ) to calculate the change in hydrogen composition of the corresponding product carbon component before and after the cracking reaction, that is, the chemical hydrogen consumption of each product (△H p,i ), and then the hydrogen carbon emissions in the hydrocracking process are allocated according to the chemical hydrogen consumption and the hydrogen carbon footprint, the method comprising:

[0035] Based on the carbon-hydrogen ratio of hydrocracking products (CH p,i ) Calculate the carbon component mass of the product (C p,i );

[0036] Based on the raw material carbon-hydrogen ratio (CH F ) Calculate the raw material mass of the corresponding product carbon component (F i ), the raw material mass of the corresponding product carbon component (F i ) and product output (F p,i ) Calculate the hydrogen consumption of the product (△H p,i );

[0037] Based on the hydrogen consumption of the product (△H p,i ), allocating hydrogen carbon emissions to each petroleum fraction product.

[0038] Specifically, the mass of the carbon component of the product (C p,i ) is calculated by product output (F p,i ) and product carbon-hydrogen ratio (CH p,i ) is calculated, and the calculation formula is as follows:

[0039]

[0040] The raw material mass corresponding to the carbon component of product i (F i ) is determined by the raw material carbon-hydrogen ratio (CH F ) and the mass of carbon component i of product (C p,i ) is calculated, and the calculation formula is as follows:

[0041]

[0042] Product hydrogen consumption (△H p,i ) is calculated by product output (F p,i ) and the raw material mass of the corresponding product i carbon component (F i ) is calculated, and the calculation formula is as follows:

[0043] ΔH p,i =F p,i -F i

[0044] The hydrogen consumption of the product (△H p,i ) and hydrogen carbon footprint to calculate the carbon emissions of hydrogen as an auxiliary material

[0045] In the embodiment of the present invention, for the petroleum fraction with an average relative molecular mass of 70 to 300 and an average boiling point of 300 to 616 K, the product carbon-to-hydrogen ratio (CH p,i ) is calculated from the average boiling point (tme) and relative density; for petroleum fractions with an average relative molecular mass of 300-600 and an average boiling point of 616-811K, the product carbon-hydrogen ratio (CH p,i ) is calculated from the mean boiling point (tme), relative density and Huang's factor.

[0046] Specific:

[0047] 1. Calculate the volume average boiling point (tv) of petroleum fractions. The volume average boiling point (tv) is calculated from the Engelhard distillation curve and the slope of the curve, that is, from the gas phase temperature when the distillation volume is 10%, 30%, 50%, 70%, and 90%, as follows:

[0048]

[0049] Where, tv—volume average boiling point, °C;

[0050] t 10 ,t 20 ,t 50 ,t 70 ,t 90 —Gas phase temperature at distillation volume 10%, 30%, 50%, 70%, 90%, °C.

[0051] 2. Calculate the average boiling point correction parameter (△me) and average boiling point (tme) of the petroleum fraction. The average boiling point correction parameter (△me) is calculated from the volume average boiling point (tv) and the slope of the distillation curve (S), where the slope of the Engel distillation curve is as follows:

[0052]

[0053] Where, S—slope of Engel's distillation curve, ℃ / %;

[0054] The average boiling point correction parameter (△me) is as follows:

[0055] Δme=exp(-0.236097-0.012557·t v 0.6667 +3.794295·S-1.99733·S 2 +0.581655·S 3 -0.063981·S 4 )

[0056] Where, △me is the average boiling point correction value, ℃.

[0057] The mean boiling point (tme) is calculated from the volume mean boiling point (tv) and the mean boiling point correction parameter (△me) as follows:

[0058] t me =t v -Δme;

[0059] 3. Calculate the relative molecular weight of petroleum fractions. Calculate the average relative molecular mass (M) from the average boiling point (tme) and relative density as follows:

[0060]

[0061] Where, CH is the carbon-hydrogen mass ratio of the petroleum fraction;

[0062] —20℃ standard relative density;

[0063] 4. Calculate the carbon-hydrogen ratio (CH) of petroleum fractions. For petroleum fractions with an average relative molecular mass of 70 to 300 and an average boiling point of 300 to 616 K, the carbon-hydrogen ratio is calculated by the following formula:

[0064]

[0065] Where: —International standard relative density;

[0066] For petroleum fractions with an average relative molecular mass of 300 to 600 and an average boiling point of 616 to 811 K, the carbon-hydrogen ratio is calculated by the following formula:

[0067] CH=2.1471×10 -22 exp(8.4312×10 -3 ·T me +1.0312×10 3 I-2.736×10 -2 ·T me ·I)·T me -0.786 I -21.567

[0068] Where: I——Huang's characteristic factor of petroleum fraction, as follows

[0069]

[0070] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0071] Example 1

[0072] This embodiment takes a 1.8 million tons / year hydrocracking unit as an example to illustrate the method of the present application.

[0073] The hydrocracking unit of this embodiment uses vacuum distillate oil (VGO) as raw material to produce light naphtha, heavy naphtha, jet fuel, diesel, tail oil and other products, and its material balance is shown in Table 1. During the hydrocracking process of this embodiment, the analytical data of the raw materials and products are shown in Tables 2 and 3.

[0074] Table 1 Material balance of a 1.8 million tons / year hydrocracking unit

[0075]

[0076]

[0077] Table 2 Properties of raw material vacuum distillate oil (VGO)

[0078]

[0079] Table 3 Properties of each fraction of hydrocracking products

[0080]

[0081]

[0082] The method of the present invention is used to calculate the carbon emissions of hydrogen consumption of products, and the process includes the following.

[0083] (1) Carbon-hydrogen ratio of raw materials and products:

[0084] Taking the light naphtha of the device as an example, its hydrogen content is calculated. From the Engel distillation data, it can be known that its volume average boiling point (t v ), tv=(28+33+39+47+58) / 5=41.0℃.

[0085] Slope of Eng's distillation curve: S = (58-28) / 80 = 0.375°C / %;

[0086] The average boiling point correction parameter is:

[0087] Δme=exp(-0.236097-0.012557·41 0.6667 +3.794295 0.375 -1.99733 0.375 2 +0.581655 0.375 3 -0.063981 0.375 4 )=2.1945℃

[0090] The average boiling point is:

[0091] t me =41℃-2.1945℃=38.8054℃;

[0092] T me =t me +273.15=38.8054+273.15=311.9554K;

[0093] The average relative molecular mass of light naphtha:

[0094] M=0.654494×10 -4 38.8054 2.3489 0.6297 -1.07276 =

[0095] 77.5820, between 70 and 300;

[0096] International standard relative density of light naphtha:

[0097]

[0098] Then the carbon-hydrogen ratio of light naphtha is:

[0099] CH=3.4707exp(1.485×10 -2 ·311.9554+16.94·0.6352-1.2492×10 -2·311.9554·0.6352)·311.9554 -2.725 ·

[0100] 0.6352 -6.796 =4.9366;

[0101] The S content of light naphtha is 10 mg / kg and the nitrogen content is 0.32 mg / kg, so the hydrogen content of light naphtha is H = (1-10-4%-0.32×10-4%) ÷ (1+4.9366) = 16.8429%.

[0102] For the jet fuel fraction, the Engler distillation data lacks the 30% and 70% volume boiling points, which can be calculated by the distillation curve correlation formula. It is known that the initial distillation point temperature is 152°C, the 10% distillation temperature is 173°C, and the 50% distillation temperature is 203°C. It is obtained that a=61.042, b=0.472, and the 30% and 70% distillation temperatures are:

[0103]

[0104] The above method can be used to calculate the hydrogen content of the feed oil and all products of the device. The results are shown in Table 4.

[0105] Table 4 Calculation results of hydrogen content in distillate oil

[0106]

[0107]

[0108] (2) Product hydrogen consumption:

[0109] The chemical hydrogen consumption of hydrocracking products can be calculated from the balance of feed carbon and product carbon and the change in the carbon-hydrogen ratio of the product and feed. Table 5 lists the carbon flow calculation results of the feed and product.

[0110] Table 5 Carbon element balance of hydrocracking unit

[0111]

[0112]

[0113] The hydrogen consumption of hydrocracking products needs to be calculated based on the carbon element balance between the raw material and the product, and the hydrogen flow rate on the carbon component of the raw material and the hydrogen flow rate on the carbon component of the product.

[0114] Taking heavy naphtha as an example, the corresponding hydrogen flow rate on the raw carbon for producing heavy naphtha = 37572.0 kg / hr ÷ 7.0828 = 5304.68 kg / hr,

[0115] From this, it can be calculated that the hydrogen consumption of heavy naphtha product = 6348.00 kg / hr - 5304.68 kg / hr = 1043.32 kg / hr. The hydrogen consumption of other products can be calculated in the same way. The results are shown in Table 6.

[0116] Table 6 Hydrogen consumption of hydrocracking unit products

[0117]

[0118] The hydrogen consumption of the products in the table is the amount of hydrogen consumed in the process of producing products from hydrocracking raw materials. It can be seen from Table 6 that the total hydrogen consumption of all products is consistent with the new hydrogen consumption of the device.

[0119] Note: The actual hydrogen consumption of the hydrocracking unit is not only used for the reaction to produce products, but also includes leaked hydrogen, discharged hydrogen, etc. The hydrogen consumption of this part is generally small and has been allocated to each product according to the consumption.

[0120] (3) Hydrogen Carbon Footprint:

[0121] The carbon footprint of purchased hydrogen is 9.64tCO2 / t, and the carbon emissions of the new hydrogen compressor are 3762kgCO2 / hr. The carbon footprint of hydrogen including chemical hydrogen consumption = 9.64tCO2 / t + 3762kgCO2 / hr ÷ 10.32t / hr = 10tCO2 / t.

[0122] Therefore, the carbon footprint of product hydrogen consumption can be calculated based on the above chemical hydrogen consumption and hydrogen carbon footprint. The results are shown in Table 7.

[0123] Table 7 Carbon footprint results of hydrocracking unit products

[0124]

[0125] It can be seen from Table 7 that among the hydrocracking products, the carbon footprint caused by the consumption of hydrogen in dry gas products is the highest, reaching 1124.370 kgCO2 / t. This is mainly due to the highest hydrogen consumption in the dry gas production process. The carbon footprint of aviation kerosene products is the lowest, mainly because of its lowest hydrogen consumption.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it.

Claims

1. A method for allocating hydrogen carbon emissions in carbon footprint assessment of hydrocracking products, characterized in that: The method comprises: Calculate the carbon component mass of the product based on the carbon-hydrogen ratio of the hydrocracking product; The raw material mass of the corresponding product carbon component is calculated based on the raw material carbon-hydrogen ratio, and the product hydrogen consumption is calculated based on the product mass and the raw material mass; Based on the hydrogen consumption of the product, the carbon emissions of hydrogen are allocated to the carbon footprint of each product.

2. The method for distributing hydrogen carbon emissions in carbon footprint evaluation of hydrocracking products according to claim 1, characterized in that: For petroleum fractions with an average relative molecular mass of 70-300 and a medium average boiling point of 300-616K, the carbon-hydrogen ratio is calculated from the medium average boiling point and relative density; for petroleum fractions with an average relative molecular mass of 300-600 and a medium average boiling point of 616-811K, the carbon-hydrogen ratio is calculated from the medium average boiling point, relative density and Huang's factor.

3. The method for distributing hydrogen carbon emissions in carbon footprint evaluation of hydrocracking products according to claim 2, characterized in that: The average relative molecular weight of the petroleum fraction is calculated from the average boiling point and relative density.

4. The method for distributing hydrogen carbon emissions in carbon footprint evaluation of hydrocracking products according to claim 3, characterized in that: The mean average boiling point is calculated from the volume mean boiling point and a mean average boiling point correction parameter, wherein the mean average boiling point correction parameter is calculated from the volume mean boiling point and the slope of the Englert distillation curve.

5. The method for distributing hydrogen carbon emissions in carbon footprint evaluation of hydrocracking products according to claim 1, characterized in that: The carbon component quality of the product is calculated from the product output and the product carbon-hydrogen ratio.

6. The method for distributing hydrogen carbon emissions in carbon footprint assessment of hydrocracking products according to claim 1, characterized in that: The raw material mass corresponding to the product carbon component is calculated from the product carbon component mass and the raw material carbon-hydrogen ratio.

7. The method for distributing hydrogen carbon emissions in carbon footprint evaluation of hydrocracking products according to any one of claims 1 to 6, characterized in that: The carbon emissions of hydrogen as an auxiliary material are calculated by the hydrogen consumption of the product and the hydrogen carbon footprint.

Images