NL8700587A - Hydrocarbon(s) prodn. - by cracking animal or vegetable oils and fats, esp. butter - Google Patents

Abstract

Hydrocarbons are prepd. by subjecting oils and/or fats of animal or vegetable origin to a petrochemical cracking process. The oils and/or fats may be used as partial replacement of the normal feed for a petrochemical cracking process. Cracking is pref. in a fluidised cracking plant. Butter is the pref. oil or fat.

Description

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Process for preparing hydrocarbons.

The invention relates to a process for the preparation of hydrocarbons by cracking organic compounds.

Such a process is known in the petrochemical industry, which, based on certain hydrocarbon fractions of petroleum, yields mixtures of hydrocarbons which generally have a smaller molecular mass than the hydrocarbons in the starting material.

It has now been found that oils and fats of animal and vegetable origin are excellent as starting materials for cracking processes customary in petrochemicals. The invention therefore also relates to a process for preparing hydrocarbons by cracking organic compounds, characterized in that oils and / or fats of animal or vegetable origin are subjected to a cracking process customary in petrochemistry.

Several cracking processes are used in the petrochemical industry. For example, high temperature steam cracking is known, the raw material being passed through heated pipes with the addition of steam and the reaction product being quenched immediately thereafter. In such processes, the cracking temperature is 600-900 ° C and the residence time in the heated zone is from a few tens of milliseconds to a few seconds. As cracking raw materials, ethane, propane, butanes, naphtha or gas oil are used. In all cases, a main product is ethylene, while the heavier starting materials also yield higher-boiling hydrocarbons and cracked petrol.

Another important process is catalytic cracking, which aims to convert heavy distillate into lower molecular weight compounds with a boiling range in the range of gasoline and middle distillate. In this process, the starting material is contacted with a silica-alumina catalyst. Although the process can be carried out with a fixed catalyst bed, nowadays only a fluidized catalyst is used. This fluidized catalytic cracking (FCC) uses small catalyst particles, for example, 20-200 µm in diameter, which are maintained in an upstream stream of gas in a fluidized state.

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The reaction temperature is generally around 500 ° C. The cracking process produces coke that deposits on the catalyst and causes deactivation. Typically, the catalyst is continuously withdrawn from the reactor and freed from coke in a separate regenerator by combustion of coke with an oxygen-containing gas. The regenerated catalyst is recycled continuously to the reactor. The heat generated during regeneration is released into the reactor by the regenerated catalyst as heat required for the cracking process. Many SiC 2 / A 2 Os catalysts are known, the zeolites of which provide the best conversions.

In the process according to the invention, oils and fats of animal or vegetable origin are used as starting materials for cracking processes customary in petrochemicals. Preferably, the oils or fats are cracked in a fluid catalytic cracking plant.

Surprisingly, the installations customary in petrochemistry appear to be suitable for cracking the oils and fats without any significant adjustments. The presence of minor amounts of water in the starting product, such as in butter, does not affect the process adversely, although the water can also be removed beforehand.

The oils and fats can be used as the sole starting material for the cracking process, but they can also be used as a partial replacement for the normal supply of petrochemical cracking plants.

It has further been found that unexpectedly valuable products are obtained with the method according to the invention. Thus, when cracking butter in a fluid catalytic cracking plant, the product is found to have a more desirable composition than the cracking product of heavy petroleum distillate. In addition, the oils and fats have the advantage that they do not contain harmful impurities, such as sulfur, or metals that adversely affect cracking catalysts.

Suitable oils and fats are all oils and fats consisting mainly of fatty acid triglycerides, of vegetable or animal origin. As main vegetable oils and fats, coconut fat, palm kernel fat, cocoa butter, palm oil, olive oil, cottonseed oil, sesame oil, sunflower oil, soybean oil, linseed oil, rapeseed oil, groundnut oil and castor oil and animal oils or fats are beef, pork and sheep fat, whale oil, cod liver oil and milk fats, such as butter worth noting.

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The use of oils and fats of animal or vegetable origin as starting material for cracking processes customary in petrochemicals will only be worthwhile if the price ratio between the raw material proposed according to the invention and the raw materials customary in petrochemical industry is in balance with the market price of the products obtained . The method according to the invention can advantageously be applied when petroleum products have a relatively high and / or oils and fats have a relatively low market value. Occasionally, a surplus of raw materials for oils and fats can be produced in agriculture and livestock farming, which oils and fats can be processed into valuable products with the advantage of the present method. For example, today an amount of butter is produced in European countries that exceeds demand. This has led to an ever increasing stock of butter, the storage of which, in particular the energy required for cooling, entails high costs, while long-term storage also reduces the quality of the butter. No satisfactory solutions to this problem have been found so far. Using the method according to the invention, butter can be converted into valuable products in a simple manner, without investment in equipment.

The following example illustrates the method of the invention.

Example

Tests were performed according to ASTM procedure D-3907-80 "Standard Method for Testing Fluid Cracking Catalysts by Microactivity Test". This test is intended to determine the activity of cracking catalysts, but was used in this case to compare the product distribution in cracking butter and gas oil over the same catalyst.

According to ASTM 3907, the reactor was a tube with an internal diameter of 15.6 mm with a reaction zone of 150 mm, in which zone 4 g of catalyst was located. The reaction zone was kept at 482 ° C. First nitrogen (30 ml / min), then the sample {1.33 g in 75 sec.) And immediately afterwards nitrogen (30 ml / min) was again passed through the reactor.

The cracking products were analyzed by gas chromatography. The catalyst used was taken from an operating commercial fluid catalytic cracking reactor. This equilibrium catalyst was of the RE-USY type with an active crystalline aluminum oxide matrix (Multicrack 25 plus-A® from AKZO Chemie Nederland B.Y., Amsterdam).

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The test was performed with anhydrous butter.

Numbers were determined by means of this test to indicate the ratio of the yields of cracked products obtained with butter to the yields that can be expected from a particular standard feed, n.1. Kuwait vacuum gas oil.

These ratios are as follows:

Gas C4's and lighter 1.08

Gasoline (C5-216 ° C) 1.05

Light cycle oil 1.12

Cooks 0.66

From these numbers it appears that the catalytic cracking of butter yields a product package which is in all respects more favorable than the said standard feed. This is especially true for the gas yield. Although in itself a higher gas yield is of little use, it should be noted here that the content of the most valuable gases (propene and butenes) is 2 to 3 times higher than would have arisen from the standard feed.

The product percentages which can roughly be expected to arise from the standard feed are shown below for orientation.

Gas (C4's and lighter 16

Gasoline (C5-216 ° C) 57

Light cycle oil 17

Coke 3.5 ε 7 0 0 58 7

Claims (4)

Process for the preparation of hydrocarbons by cracking organic compounds, characterized in that oils and / or fats of animal or vegetable origin are subjected to a cracking process customary in petrochemistry. 2. Process according to claim 1, characterized in that the oils and / or fats are used as a partial replacement for the normal supply of a cracking process customary in petrochemicals. Process according to claim 1 or 2, characterized in that the oils and / or fats are cracked in a fluid catalytic cracking installation. 4. Process according to claims 1-3, characterized in that butter is used as oil or fat. +++++++++++ ¢ 700587