Pipeline quality

Selexol. licensed by the Norton Company, uses the dimethyl ether of polyethylene glycol. A Selexol plant can be designed to provide some selectivity for H2S. For example, the plant can be designed to provide pipeline quality gas (0.25 grains H S/IOOscf) while slipping 85% of the COi. ... 

In the solution, the amine DIPA is meanwhile able to achieve pipeline quality gas (0.25 grains IT/lOOscf). 

This process uses propylene carbonate as a physical solvent to remove CO2 and H2S. Propylene carbonate also removes C2+ hydrocarbons, COS, SO2, CS2, and H2O from the natural gas stream. Thus, in one step the natural gas can be sweetened and dehydrated to pipeline quality. In general, this process is used for bulk removal of CO2 and is not used to treat to less than 3% CO2, as may be required for pipeline quality gas. The system requires special design features, larger absorbers, and higher circulation rates to obtain pipeline quality and usually is not economically applicable for these outlet requirements. 

The chemical solvent DIPA acts as secondary treatment to remove H2S and CO2. The DIPA allows pipeline quality residual levels of acid gas 10 be achieved easily. A stripper is required to reverse the reactions of the DIPA w ith CO2 and H2S. This adds to the cost and complexity of the sys... 

It is difficult to remove H2S to pipeline quality with a membrane sy stem. Membrane systems have effectively been used as a first step to remove the CO2 and most of the H2S. An iron sponge or other H2S treating process is then used to remove the remainder of the H2S. 

Another problem is when the carbon dioxide content of natural gas is too high and must be lowered to produce pipeline-quality gas. Although the current practice is to vent this CO, sequestration of CO, in underground geologic formations is being considered. Already, in the Norwegian sector of the North Sea, CO, has been injected into saline aquifers at a rate of 1 million tons a year to avoid... 

D. Blum Just going a bit further, the liquid-phase methanation process now uses one reactor. You can or you cannot use a polishing reactor as the economics dictate. You can actually go right to pipeline quality gas in one reactor, which is equivalent to about 99.8% conversion of a 20% CO feed gas. We envision at this moment that combined shift-methanation could be done in the same single reactor. It would obviously require lower feed gas rates so you may need two of these reactors. We don t exactly have the numbers yet. I think that s one of the areas that deserves future work. 

In summary, the current emphasis in R D management circles seems to be upon reducing risk, improving pipeline quality, and improving team accountability and communications between functional specialties and units. 

A time-and-motion modeling mind-set can easily blinker analysis of how best to improve the value created by research. Truly useful simulations of drug discovery must go beyond simplistic assumptions about yields at stage gates and address the causes of failure, starting to quantify the common concept of pipeline quality. ... 

The emulsion must be separated by the addition of chemical demulsifiers before the crude oil can be accepted for transportation. The quality criteria for a delivered crude oil are the residual salt content and the water content. For the oil to have a pipeline quality, it is necessary to reduce the water content to less than approximately 1.0%. 

All gas turbines intended for service as stationary power generators in the U.S. are available with combustors equipped to handle natural gas fuel. A typical range of heating values of gaseous fuels acceptable to gas turbines is 900 to 1100 Btu/scf, which covers the range of pipeline-quality natural gas. Clean liquid fuels are also suitable for use in gas turbines. 

The present state-of-the-art technology for the conversion of raw gas exiting the gasifier into pipeline quality SNG is not very satisfactory. Enormous volumes of gas are cooled, reheated, cooled again, reheated again, and cooled for a third time. Steam is added to the gas, and condensate is subtracted twice (earlier and later). This series of operations is complex and costly. 

The natural gas feed to the cycle (stream 1) is typical of pipeline quality natural gas within the U.S. containing both sulfur odorants and higher hydrocarbons (C2H6, CsHg, etc.). The odorants... 

For high-throughput purification pipelines, quality assessment (QA) procedures are required which can be carried out in parallel in relatively high throughput. The QA steps routinely carried out in the OPPF are summarized in Table 2.3. Other methods that have been used in HTP projects include one and two-dimensional NMR screening and differential scanning calorimetry. 

The GCs process reservoir fluids to make pipeline quality oil, dehydrated gas for injection, and treated water for injection into disposal wells. 

The initial biogas recovered is an MHV gas and is often upgraded to high heat value (HHV) gas when used for blending with natural gas supplies. The annual production of HHV gas in 1987, produced by 11 HHV gasification facilities, was 116 x 106 m3 of pipeline-quality gas, ie, 0.004 EJ (121). This is an increase from the 1980 production of 11.3 x 106 m3. Another 38 landfill gas recovery plants produced an estimated 218 x 106 m3 of MHV gas, ie, 0.005 EJ. Additions to production can be expected because of landfill recovery sites that have been identified as suitable for methane recovery. In 1988, there were 51 sites in preliminary evaluation and 42 sites were proposed as potential sites (121). 

High Heat- Value Gas. High heat-value (high Btu) gas (7) has a heating value usually in excess of 33.5 MJ/m3 (900 Btu/ft3). This is the gaseous fuel that is often referred to as substitute or synthetic natural gas (SNG), or pipeline-quality gas. It consists predominantly of methane and is compatible with natural gas insofar as it may be mixed with, or substituted for, natural gas. 

Cost-of-service tariff for sale of pipeline quality gas by the partnership to pipeline members. 

The American Natural Resources Co. had difficulty raising money for the mammoth project which would have produced 125 million cubic feet per day of pipeline quality high-Btu gas. Officials of the company had said that normal debt financing isn t possible because lenders aren t willing to put up the money for what is still an untried process in the United States. Yet outside financing is needed because the partners in the project can only afford to put up 25% of the cost of the plant themselves."... 

While on the subject of coal gasification, we should remember that low- and medium-Btu gas from coal should be considered as lower cost alternatives to pipeline quality high-Btu gas. For one thing, the capital investment for low-Btu gas plants is lower than the high-Btu gas plants as shown below ... 

TABLE 20.3 Typical Pipeline Quality Natural Gas3... 

The transmission function covers transport of the processed pipeline quality gas from the gas-processing plant to major markets. About two-thirds of U.S. marketed gas production reaches the ultimate consumer through a network of some 250,000 miles of pipelines. Other deliveries may be made directly to industrial consumers or to city distribution systems. 

Product Losses Account must be taken of the product loss, the slow gas in the permeate (such as CH4), or the fast gas in the residue (such as H2). Figure 22-79 illustrates the issue for a membrane used to purify natural gas from 93 percent to pipeline quality, 98 percent. In the upper figure, the gas is run through a permeator bank operating as a single stage. For the membrane and module chosen, the permeate contains 63 percent CH4. By dividing the same membrane area into... 

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