Fundamentals of Natural Gas Processing explores the natural gas industry from the wellhead to the marketplace. It compiles information from the open literature, . How to Write Better Essays. Bryan Greetham. Key Concepts in Politics. Andrew Heywood. Linguistic Terms and Concepts. Ge. Request PDF on ResearchGate | On Feb 23, , Reza Mosayebi Behbahani and others published Fundamentals of Natural Gas Processing and.
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Spring Designer's Handbook, Harold Carlson. 2. Computer-Aided Graphics and Design, Daniel L. Ryan. 3. Lubrication Fundamentals, J. George Wills. 4. Printed: 26 April - [Natural Gas Processing Principles and D.Y. Peng and D.B. Robinson, Industrial and Engineering Chemistry Fundamentals, Vol. 15, . The second part addresses each step of natural gas processing, with a focus on gas plant processes. The chapters in DownloadPDF MB.
It compiles information from the open literature, meeting proceedings, and experts to accurately depict the state of gas processing technology today and highlight technologies that could become important in the future. This book covers advantages, limitations, and ranges of applicability of major gas plant processes to provide a sound understanding from system fundamentals to selection, operation, and integration into the overall gas plant. It also describes the major operations involved in bringing the gas to the plant, information not usually discussed in most gas processing books. Comprehensive chapters cover field operations, inlet receiving, compression, dehydration, hydrocarbon recovery, nitrogen rejection, liquids processing, sulfur recovery, and the increasingly popular liquefied natural gas industry, focusing on liquefaction, storage, and transportation. The book also discusses plant economics, offering ways to make initial cost estimates of selected processes and determine capital costs of gas processing facilities.
Important impurities found in natural gas . Most gas produced contains water, which must be removed. Concentrations range from trace amounts to saturation.
Sulfur species. Trace quantities of mercury may be present in some gases; levels reported vary from 0. Typically, mercury level in pipeline gas should be reduced to 0. Although the gases shown in Figure High hydrogen sulfide contents e. Some gas-gathering systems in the United States operate below atmospheric pressure.
As a result of leaking pipelines, open valves, and other system compromises, oxygen is an important impurity to monitor. A significant amount of corrosion in gas processing is related to oxygen contamination.
Mix P Mole Wt. Search Main Menu iC5 0. Number of lbs. Flow is We will use primarily the psia chart. Here are the average deviations of the values of some of the important correlations. Latent heats for pure compounds can be found from the thermo property tables or the Mollier diagrams given in the GPSA Data Book from the data in Maxwell. These of course are more accurate and should be used for detailed design.
We have been discussing essentially the enthalpies of gas. For systems that remain liquid the difference in enthalpy between two temperatures is found by multiplying Cp T1. When we have liquids and vapours occurring together we have to take into account the heat accompanying a change of phase or the latent evaporization or condensation. We should also discuss liquids and mixtures of liquids. To handle the case of compounds at conditions above their critical points but still in a liquid. Peng Robinson correlations give much better accuracy.
A study of J. T2 or subtracting the enthalpies. Redlich Kwong. Then proceed as follows: If you are chilling a rich gas in which there is lots of condensation and you wish to find heat duty: Find enthalpy at inlet temperature and pressure 2. The process occurs at constant enthalpy. Run a flash calculation at outlet temperature and pressure to see amount and composition of liquid and gas phases.
Calculate enthalpy of each phase at outlet conditions using compositions found from 2. Calculate the weight fraction of liquid and gas present.
Enthalpy of Gases in Solution Therefore. Gas specific gravity can also be calculated using equation A very important part of the calculation of this value is the reference state. The newer contracts just take a continuous sample. This has been discovered by some field work by G. Search Main Menu on thAs. The ideal gas heating value is calculated by the equation: This is the value obtained by measuring the heat formed and cooling the products of combustion to F including condensing the water vapour.
In this case the water is not considered to be condensed. Net Value.. These are two kinds of heating values: In most applications in the gas industry the gross heating value is used. Thus the Mollier chart can also be used in this regard. Palmer and others of Maloney Steelcraft Ltd. The real gas heating value H is set by the equation: See pg.
To find the heating value in this case multiply the gross dry basis by 0.
A calorimeter on pipelines measures the heat content as saturated with water vapour. The GPSA has set up a standard for this calculation for mixture. Data for equation is also found in Table 2.
Gross Value. This is particularly important in compressor and expander calculations. IGT Bulletin 32 for other components. To prevent confusion. IGT Bulletin 32 for nonhydrocarbons. Natural Gas Expansion-Temp. Reduction Curve Based on.
Note that N2. Viscosity is measured normally in metric units of centipoise. Kinematic Saybolt. H2S air are more viscous at same temperature as compared to hydrocarbons. It is defined by: The viscosity of liquid sulphur is quite special.
A much more extensive discussion is given in the chapter on viscosity in Maxwell6. Another way is to calculate the reduced temperature and reduced pressure and use. Here the viscosity in centipoise is plotted versus temperature. Except at very high values pressure does not affect viscosity.
The viscosity of gas at high pressure can be found by use of Fig. Similarly Katz7 gives data for individual compounds on Pg. Multiply by. Effect of Temp. Hydrocarbon liquids conductivity is given in Figure 2. At high pressures. Figure Also some data for H20 is given in Maxwell. Junk and Cumming A gas of the composition given below is to be recycled to recover the sulphur.
Problems 7. Also Katz.
They give a thermal conductivity ratio vs Pr and Tr where thermal conductivity ratio is: Determine the amount of make-up gas that must be supplied to the facility to handle this requirement or the amount of gas that is available for sale. Furnace No. Search Main Menu processing plant that is built for extracting the products produced. The efficiency of each is also given. The process duty on each of the furnaces is as follows.
The heating load of a processing plant is made up of 4 furnaces. The gas is sweet and the gravity of the gas is 0. A gas of the following composition is to be processed for ethane and propane plus recovery. You are to determine the heat duty of the high pressure heating coil in BTUs per hour.
Assume fuel gas is supplied from down stream of plant i. How many days interruption could the process plant stand per year and still break even if it used interruptable gas instead of firm gas? The sketch below shows the flow scheme.
The gas is delivered from the wellhead through a heater to a pipeline that operates at psig. McGraw Hill. Hydrocarbon Processing. Thermal Properties of Hydrocarbons.
Hydrocarbon Data Book. Private Communication. Jarl and E. Proceedings 62 Gas Processors Convention. February Handbook of Natural Gas Engineering. May Industrial and Engineering Chemistry Fundamentals. Part 14". Starling and M. Hopke and C. Bishnoi and D. Gas Processing of Canada. Industrial and Engineering Chemistry.
Redlich and J. Trans AIMS. Chemical Engineering Progress. January 2. Van Nostrand.
Part II". Chemical Engineering Science. Mannan arid J. Peng and D. Gulf Publishing Co. September Reading List 1. March 10— Part 15". June Canjar Maning. Also it is hard to compress. A single continuous media containing one or more substances in which the relation between temperature.
Search Main Menu 3. Another way is to use the Clausius Clapeyron Equation which explains how a phase is changed. This equation can be expressed as follows: Gases Distinguishing feature is that it occupies the space of container and it can be compressed easily. Liquid It takes the shape of the bottom part of a container. The diagram shows when a single phase and when two phases are present. We encounter many physical conditions in handling fluids in which two phases are present.
In the gas industry we are lucky in that we only need to consider liquid and gas phases. Figure 3. Search Main Menu It has definite shape and is not compressible. This is considered later in this section. We do have the special case of elemental sulphur in gases containing amounts of H2S.
We can have several liquid and solid phases. This led to the concept of the critical point. Some of the more important pioneers are: In studying about phases we initially will try to understand visually what happens between phases and later. V is specific volume i.
Surface B Liquid and Vapour in equilibrium. These are: PT diagrams Figure 3. Let us consider projections of this model onto a two-dimensional surface. We have two normal types of diagrams. Surface C Solid and Vapour in equilibrium. SLG Three phases present. PV diagrams Figure 3. PV Diagram. Some examples of solid. Search Main Menu Figure 3. When going from D to E the phases are Solid. The point C in PV diagram and the top point on the liquid vapour line in PT diagram is called the critical point.
When reducing the pressure along the curve ACB no change of phase occurs. Each individual substance has a definite critical temperature and critical pressure. It is the unique point for substance where the liquid and gas phase become identical.
Table 3. There is also a critical temperature and pressure for mixture which will be discussed later. Here are some data on common critical points. It would contain liquid of specific volume. Also consider the conditions of vessel containing a certain weight of material with temperature T3. This rule applies to systems in equilibrium and states that the number of Natural Gas Processing Principles and Technology.
Search Main Menu n Pentane Single Component a A functional relationship of the form Equation f P. The boiling point is the temperature at which the vapour and liquid phases are in equilibrium when the vapour pressure is one atmosphere. The surface which this relationship describes has dis continuities in it because of the existence of vapour-liquid.
X is the composition. The fundamental difference between single component systems and complex systems is that every time we add one more component we gain one additional degree of freedom.
Some examples are: Every point represented on such a diagram will have a particular specific volume associated with it. That is we may arbitrarily specify one additional variable and for a binary system. Thus by specifying different temperatures a vapour pressure curve can be determined. It is obvious from this relation that a three dimensional model can no longer be used to pictorially represent the complete behaviour of even a vinary system. The concept of two or more phases co-existing.
Any three dimensional representation of the behaviour of a system containing more than one component will of necessity be capable of showing the values of only three of the possible variables. The choice is arbitrary. It continues until point 3 is reached where total condensation is experienced bubble point. It will be appreciated that the additional degree of freedom means that what were points for one component are lines for two components.
It will be noted that since volume has been omitted in this diagram. In this way the saturated liquid line of Figure 3. At point 2 condensation starts dew point. The diagram is terminated on the P-x plane by an arbitrarily isothermal plane which leaves its trace on the bubble point surface and on the dew point surface.
These two surfaces. In this figure let us consider going from point 1 to point 4 by increasing the pressure. Let us consider PT diagrams.
Search Main Menu excluded because of the complexity of the diagram and because it is seldom pertinent in gas processing studies. Another useful diagram is the TX diagram Figure 3. On a P-V-T surface this occurs every time the single phase region intersects a two phase region.
This two-phase volume is terminated at the left side of the figure by the vapour pressure curve of pure A denoted by the line The critical point has become a critical line or critical locus for the binary system. This is because the only lines one sees in space are those formed when two surfaces intersect non-tangentially. This locus.
The characteristic features of the diagram are somewhat more difficult to visualize than they were in the P-V-T diagram for a single component. Different Composition A PT diagram for constant composition can be shown as: Two Components. For example Figure 3. Please note that Figures 3. The highest pressure at which two phases can exist together is the cricondenbar and the maximum temperature at which two phases exist is the cricondentherm.
This shows how two components can be separated by distillation. At temperature T1 the gas composition is xG and the liquid composition is xL. Temperature Composition Diagram In Figure 3.
We also have a useful representation by the composition diagram with P and T constant. When non—ideal solutions occur. The critical point is formed by the intersection of the dew point and bubble point surfaces.
This is shown in Figure 3. Also note that the critical point for a binary system is not necessarily the highest temperature or pressure where two phases can exist together for any composition.
Vapour Liquid Composition Diagram This figure is also important in distillation. Dew Point This is defined as the temperature at which condensing takes place. Non-ideal Temperature Composition Diagram 3. It varies. Bubble Point This is defined as the temperature at which the first sign of vapour appears. This varies with pressure. With a pure substance the bubble point and dew point are the same.
For a system to totally condense it is at its bubble point and for a system to totally evaporate the system has to be at its dew point. These liquids may be re-evaporated by dry gas if a cycling scheme is used. Another phenomenon is. At constant temperature. Thus liquids will drop out in the reservoir when the pressure is decreased and may be lost.
The reverse of the above procedure. This phenomena is retrograde condensation and is particularly important in natural gas reservoirs. At W liquid begins to form on pressure reduction and continues until R is reached where the maximum amount of liquid is developed. Retrograde Phenomena I 3.
Search Main Menu of variable composition. Havlena1 et al. For obvious reasons. Retrograde Phenomena II 3. Search Main Menu Also. This is called isobaric retrograde condensation. PF is the initial reservoir pressure. As pressure decreases during production. Thompson effect. Even when the temperature is reduced to that at the separator because of the Joule. Search Main Menu Reservoir temperature is less than critical.
The reservoir temperature is well above the critical. Also we can get both maximum and minimum boiling points.
With hydrocarbons the ideal solution principle is generally followed. In general. Search Main Menu This is the same as a dry gas. The problem that occurs is that at high pressures and temperatures gas containing high percentages of H2S seem to dissolve elemental sulphur. It shows that as the temperature and pressure increase. Weiland2 reports on this.
Condensate will also normally exist in the separator. The reservoir will sometime in its life be in the two phase region. The well known work of D.
Volume of solution of a mixture is equal to the sum of the volume of each individual component. Condensate Reservoir Phase Envelope The reservoir temperature is between critical and cricondentherm.
He developed a correlation that indicated the probability of deposition. Search Main Menu dropped. This elemental sulphur plugs the well tubing and gathering lines. This is given in Figure 3. Hyne3 has made a study of sour gas reservoirs in Alberta to see when the problem of deposition occurs and what causes it.
He found that with high H2S wet gas streams i. Hyne and E. Chemical Engineering. Pot and O. Erbar and R. Also presented to the Society of Petroleum Engineering. Schweitzer and C. October January Katra and B. Reservoir and Pressure Decline Studies". Reservoir calculations. Absorption calculations.
We use vapour liquid equilibrium data for: Refrigeration calculations. Two phase pipeline flow calculations. Distillation calculations. Inlet separation calculations. Search Main Menu 4. We are very fortunate as compared to crude oil systems which do not have equilibrium data for individual components but have to use correlations depending on average boiling point.
Tower pressure calculations. This is sort of an ideal vapour pressure. We can extend the application of calculated K to higher pressures by use of the term fugacity "f".
For liquids a similar type of equation can be developed using the difference between the actual change in volume and the change in volume of an ideal solution. Using fugacities and assuming ideal solutions we have: If there is no difference the fugacity is equal to fugacity of the pure component times the mole fraction. Similarly a Raoult Law type of equation can be developed: This is called the convergence pressure.
In the literature there are data for many systems -benzene. Also given in this manual are K values for various oils as a function of their boiling point. This applies for any temperature and for each component. From these measurements and by calculations an extensive set of K values for methane to Decane.
It should be noted how the actual "K" converges to 1 at high pressure. That is the pressure at which for this set of data all values of "K" converge to one. Sage and Lacey at Cal. Figure 4. Many others such as Kobayshi. Search Main Menu The above ways of calculating "K" are satisfactory part of the time but not always. It is calculated primarily from the composition of the system. Kwong3 equation can also be used. Thus it can be seen that convergence pressure is the critical pressure of a binary and that it has for its critical temperature the temperature in question.
Carnahan and Kwok1 give a good discussion of these methods. At the critical pressure and critical temperature of system "K" must equal 1. At psia the K values are all the same. For two phases to exist the heavier phases' "K" must be less than one and lighter phases' "K" must be greater than 1.
The concept of convergence pressure is used as a means of correlating K data. The three major methods are as follows: The effect of convergence pressure selection can be seen from Figure 4.
We will start with a discussion of the c approach first. For a binary system we can see this effect if we plot K versus the pressure at a constant temperature as shown in Figure 4. As can be seen at low pressure the selection of the convergence pressure is not important. Seader4 and the Prausnitz Chueh12 and the Soave18 methods for calculating "K". Rubin2 equation and its modification by Starling15 is used for this although the Redlich. Prime example is the Chao. Search Main Menu Figure 4.
Binary System "K's" As was stated the convergence pressure is a means of correlating K data for a particular composition. P1 The method given below is probably satisfactory. For natural gas systems it has been found that the convergence pressure is a function of temperature and the composition of the liquid phase. Join the heavy and light component together as shown on the Figure and read off PK against operating temperature..
The heavy component is estimated from the composition of the remaining components. A visual estimate is usually good enough. Natural Gas Processing Principles and Technology.. T Thus for a binary system PK is independent of the composition or independent of the lightest component. The method is to take as the lightest component present in any significant quantity Identify the lightest hydrocarbon component which is present at a concentration of at least 0.
A shortcut approach good for most hydrocarbon systems is to calculate the weight average Tc only. Using the convergence pressure determined in Step 4 together with the system temperature and system pressure. Search Main Menu If the liquid phase composition is unknown. If the liquid composition was initially assumed. Check if this is same as assumed value and if not redo procedure. When the averaged pseudo heavy component is between two real hydrocarbons.
Read off PK at the operating temperature. Trace the critical locus of the binary consisting of the light component and pseudo heavy component. Calculate the mass average critical temperature and critical pressure for the remaining heavier components to form a pseudo binary system. If the differences between the assumed and calculated compositions are significant. These are other methods.
Read the convergence pressure ordinate at the system temperature abscissa from Figure. Method of Winn 1. Calculate critical temperature of pseudo heavy components by any method. Estimate convergence pressure and calculate liquid phase analysis. Divide liquid into two components. Run a flash calculation at an assumed PK.
Find intersection of operating temperature with binary critical pressure for each heavier component and the lightest component. Method of Lenoir and White 1. Must estimate effective boiling point of the heavy component while doing this.
Divide the system into a fictitious light component and fictitious heavy component. Calculate the effective BP of the light component EBPL from data on effective EP of compounds given in article and graphs showing correction factors as compared to lightest component.
Calculate weight fraction analysis based on lightest component free basis. Check to see if general assumption was OK Figure 4. Assume a convergence pressure and calculate a liquid phase composition molal volumes satisfactory. The sum of these values is the calculated PK 5. Also Example Problem 1 shows this method. Multiply pressures obtained by corresponding weight fraction of heavier component.
The method is reported to be good for heavier mixtures as found in refinery streams. The method requires the calculation of the convergence pressure as previously discussed. These charts are used as a standard by the API. To correct for non alphatics such as H2S.. They are particularly suited to computer calculations. A typical set of curves is shown in Figure 4. This is shown in Figure 4. The presence of these compounds usually give higher convergence pressures.
Search Main Menu "K" Data by the Chao-Seader Method This was the first general correlation to try to account specifically for non idealities in the liquid phase. This is the same as in the method of finding the enthalpy given in Chapter 2.
All the above can be found from properties of pure components. Or 0 vi0 and vi can be found from the two following equations. This program is considered to give good data over a wide range of temperatures and pressures.
A and B are constant for component expressed in terms of their critical conditions and are for the mixture Ai and Bi are for the pure component and Z is the mixture.
Mixing Rules. The BWRS equation has the following form see also equation 2. It is available as a computer program through the GPSA. Table 4. Search Main Menu This equation can be used to find "K" accurately over a wide range of temperatures and pressures.
The interaction parameters have little effect on bulk properties such as density and enthalpy but can greatly improve K-value predictions. This data is found from experimental data on binary systems.
This method of course requires computer programs for its use but is generally quite good. The BWRS mixing rules contain a binary interaction parameter mij for each pair of components. It is applicable to all types of gas processes including cryogenic expander and absorption of oil plants. It may not be accurate for heavy gas reservoir systems such.
From the vapour and liquid composition calculate the vapour and liquid density. The small "a" and "b" are the constants in the Redlich equation.
Perform a flash calculation on the mixture using arbitrary "K". Now the fugacities of individual components in the vapour phase and liquid must be equal. Using the BWRS equation above for fugacity calculate the individual fugacities for each component. Prausnitz has allowed for the effect on the presence of other components on the constants for individual components in calculating the fugacities. The procedure for calculating "K" is as follows: The BWRS equation is a very good overall thermodynamic prediction method available in the gas processing industry.
Search Main Menu The other important change is that the requirement of sometimes having a hypothetic liquid state for the development of the term vi0 is avoided by the development of an assymetrical standard state. The selection of the appropriate equation of state or method for "K" values is given in references 4 and 5 of the reading list. For the details of the method please refer to reference 12 or suggested reading reference 2.
Some comparative data versus experimental values are given in Tables 4. No data Not limits hydrocarb prediction for H2 or accurat ons only. Example Problem 4. In this case we wish to determine when the first bubble or gas starts to form. The operating pressure is psia. Now here we know x. These illustrations are given for example only. Search Main Menu The reverse of a dewpoint calculation is a bubble point calculation.
Set up a table as shown below. The gas is the overhead from an absorber. All these calculations are best done using some sort of computer program if it is available.
We add up all the y's from the equation: Find the proper temp. Now check assumption of PK. Determine the tower operating pressure. The overhead product has an analysis of the following: Solution Find the accumulator pressure by doing a bubble point. Assume this pressure is 10 psi greater than the accumulator pressure. Tower pressure is psia or This can happen for inlet separators.
Search Main Menu At depropanizing tower is operating with all the overhead product condensing. A comparison of a dew point calculation using different K data is shown below. Assume an L and thus a V. Select "K" for each component at the temperature and pressure of the system. Could also possibly use data from "K" versus Boiling Point Curves. Check this value against assumed value. It is desired to determine the composition and quantity of gas that comes from the rich oil flash drum.
For example methyl mercaptan data is given in the literature see Haddon and Grayson article. Repeat calculation until assumed value is equal to calculated value. The amount of rich oil is For determining the "K's" for sour gas the method of Lenoir and White or the Soave method is probably as good as any when using charts. The refrigerant enters the exchanger as a liquid and leaves as a vapour.
Other methods are given in Campbell. Determine the type of cooling medium that has to be used with this tower. The Peng Robinson or the Soave methods give reasonable values for sour gas "K's" from the computer programs.
To find the "K" value for heavy components we can either use data in the NGPSA book for various 1 boiling point materials or by plotting of log "K" versus for various components in the mixture at Tb the system pressure and extropolate to the Tb of the heavy component.
Search Main Menu and nitrogen have been discussed in some detail by Lenoir. The following conditions should be investigated: Use the following data: It has a high methyl mercaptan CH3SH content.
Some concern has been expressed as to whether most of this material will stay in the gas. Search Main Menu H2S 6.
Grayson and C. Chao and J. Lenoir and G. The GPA. Industrial Engineering and Chemistry Fundamentals. Share Comp. Series in Hydrocarbon Processing. Hydrocarbon processing. Proceedings of Sixth World Petroleum Congress. Prentice Hall. An Equation of State". Carnahan and Y. Published by J. Progress Symp. Engineering Service Chem. Do It Right". Carahan and Y.. November Erbar and W. Starling and J. The Mark V Computer Program. IEC Fundamentals. Robinson and G. McKee, W. While and T.
Wilcox and S. This may not be the case, but no detailed work has been done to show that reservoirs are not saturated. If they form in pipelines they cause serious plugging problems. Many liquids, hydrate and solid phases occur. Figure 5. Initially it is a gas G. Upon cooling, a liquid phase that is essentially water L1 is formed and the gas becomes richer in propane but is still just a gas G, L1 are present. On further cooling, a propane rich liquid is formed L2 and only two liquid phases are present L2 and L1.
Further cooling brings the formation of a propane water hydrate H while the propane rich liquid remains. More cooling brings about the formation of solid propane while the hydrate compound remains. The pressure, temperature diagram for C3 and H2O is shown in Figure 5. Similar types of diagrams can be developed for other hydrocarbon-water systems. See Katz, Pages forward. This chart also can be used to illustrate why the specification of a water content of 4 lbs per MMSCF for pipeline gas is required in Canada.
Gas Containing Significant Amounts of Non-Hydrocarbons In the case where there are significant quantities of non-hydrocarbons such as nitrogen, hydrogen sulphide or carbon dioxide present, the water content of the gases are quite different than compared to that obtained from Figure 5.
Nitrogen does not hold as much water as natural gas. Katz, on pages and , discusses this. The acid gases, H2S, and CO2 can hold a much greater amount of water, particularly at high pressures.
This is explained by the fact that both water and the acid gases are polar compounds and hydrocarbons are not. To find the actual water content of gases containing large amounts of non-hydrocarbons, it is best to consider each non-hydrocarbon component separately, then add the separate fractions of the gas to find the total water content.
The equation for this is Equation Y is the mole fraction of each component. An example of this procedure is given in Example Problem 5. This method has worked out quite successfully at Pine Creek, Alberta, where it was found that water content of the sour gas that was to be dehydrated was much higher than that obtained from the sweet gas curves. For a description of the facilities and some special test work for this field see A.
Masuda and P. Method of Wichert Moore, Heidemann, and Wichert have developed a new method for estimating the water contents of sour natural gas based on extensive field tests of sour gas in Canada. The figures are given for H2S as the acid gas component. Example Problem 5. Determine the expected water content of gas of the composition given below.
Method 1 Use the partial water content for each major different component.
Then the calculation becomes: Thus, either method can be used for calculating water content at high acid gas concentrations. Hydrocarbons from propane through lube oil are given. This is used for trace water determinations. Actual data needs to be published on these systems.
Special data should be collected for the absorption of natural gas by the various sweetening solvents. Karl Fisher Reagent. These values are a function of temperature only. Henry's law constant for various gases given in Perry and Katz. Search Main Menu 5. Generally hydrocarbons that have been in contact with water must be dried before being stored. A Henry's law equation or a modification of it can be used. For drying liquid propane from storage wells CaCl2 pellets are often used.
A salt tower is often satisfactory for the heavier compounds like diesel oils. Data for the solubility of specific compounds or products. Particular care has to be taken when using this apparatus that a water dewpoint and not a hydrocarbon dewpoint is recorded. Some typical formulae are. Diethanol amine absorbs about twice as much and sulphinol considerably more than this.
When the host structure is water the clathrate is called a hydrate. Search Main Menu CH4. A clathrate compound is one formed by the complete enclosure of one or more species of a molecule in a suitable structure formed by another species.
Gas hydrates have some properties ascribed to chemical compounds and Natural Gas Processing Principles and Technology. This applies for the smaller molecules like CH4.