Chemical Injection

As the first well is being drilled the template is connected to the host facility with flowlines, umbilicals and risers. A Chemical Injection Umbilical will also typically be laid to the template or subsea facility and connected to a distribution manifold. 

E. D. Holsteiu, "Status and Oudook for EOR by Chemical Injection," No. 371-C, paper presented at xR Mmerican Petroleum Institute Meeting, Dallas, Tex., Apr. 4, 1982. 

Improper backwash. Blowoff of resin from the vessel during the backwash step can occur if too high a backwash flow rate is used. This flow rate is temperature dependent and must be regulated accordingly. Also, adequate time must be allotted for backwashing to insure a clean bed prior to chemical injection. 

The basis of chromatography is in the differential migration of chemicals injected into a column. The carrier fluid takes the solutes through the bed used for elution (mobile phase). The bed is the stationary phase. Based on mobility, the retention-time detectors identify the fast and slow-moving molecules. Based on internal or external standards with defined concentration, all unknown molecules are calculated in a developed method by software. GC columns are installed in an oven which operates at a specified temperature. A diagram of an oven with GC column is shown in Figure 7.16. 

It thus becomes necessary to preempt the problem by tightly controlling the FW pH, temperature, and residual hardness levels where MU water source contains a high silica level (say, over 20-30 ppm Si02). The location of FW line chemical injection points and the type of chemicals dosed also may influence the risk of silicate sludges and scales developing, and these factors may also need to be considered. 

Steam drums (top drums) often are difficult to enter or move around in because of the fixed mechanical equipment contained within the confined space. It should not be assumed that this equipment has always been correctly reinstalled after any previous inspection or maintenance programs. Consequently, steam drums should first be inspected for proper location, orientation, and anchoring of steam separators, FW lines, baffles, continuous BD lines, and chemical injection lines. 

The chemical injection line should be found in the drum at a point after BW and FW mixing and before the downcomers (the coldest point of the boiler), to minimize adherence of precipitating sludges onto tube walls. 

The effectiveness of alkaline additives tends to increase with increasing pH. However, for most reservoirs, the reaction of the alkaline additives with minerals is a serious problem for strong alkalis, and a flood needs to be operated at the lowest effective pH, approximately 10. The ideal process by which alkaline agents reduce losses of surfactants and polymers in oil recovery by chemical injection has been detailed in the literature [1126]. 

D. T. Wason. Enhanced oil recovery through in-situ generated surfactants augmented by chemical injection. US DOE Rep DOE/BC/10847-20, Inst Gas Technol, Chicago, IL, August 1990. 

Intraperitoneal Route. Kruger et al. (1962) demonstrated the efficiency of absorption of some chemicals injected IP, while Lukas et al. (1971) showed that compounds administered IP are absorbed primarily through the portal circulation. 

Midc, A.J. Nozik, Electron relaxation in colloidal InP quantum dots with photogenerated exdtons or chemically injected electrons, J. Phys. Chem. B 107 (2003) 102-109. 

Investigation of foaming characteristics of crudes and effectiveness of anti-foam chemicals should he conducted at an early stage of the design of gas/oil separators to assess the economics of extra residence time (larger separation vessels) vs. anti-foam chemical injection as the means of preventing foam... 

Chemical injection nto the flowline near ihe well head is usually a practical approach With many well systems. chemical injection at each well presents problems too Initial cost of many injectors is high, and maintaining and servicing them is lime consuming. 

A common point of chemical injection is at the main header. Injection here insures that chemical will be introduced continuously into all of the production The single injector gives a low-cost initial installation and provides for minimum maintenance and servicing Such savings may offset the cost of extra chemical which is usually required because of less agitation and lime. 

There is no single best chemical injection point Fach system must he evaluated to determine how it can host he applied... 

Chemical injections into pine trees have been reported to have stimulatory effects on the natural production of resins and terpenes and may result in high yields of these valuable chemicals. Combined oleoresin—timber production in mixed stands of pine and timber trees is under development, and it appears that when short-rotation forestry is used, the yields of energy products and timber can be substantially higher than the yields from separate operations. 

NOTE A corporation stop is a chemical injection device that screws into a recirculating cooling waterline. It includes a nozzle assembly to disperse chemicals into the center of the line for even mixing (although sometimes a static mixer is a useful extra) and permits the removal of the injection check valve without the need to shut down the line. 

Flow assemblies are becoming more common as an arrangement for housing pH electrodes, conductivity cells, and chemical injection ports. Typically they are constructed of plastic materials, such as Schedule 80 PVC or glass-filled polypropylene. 

Flow assemblies can also be used to incorporate chemical injection ports. Chemical injection should take place at some distance from... 

Many flow assemblies are poorly designed and fail to provide for easy access and monitor probe cleaning. Chemical injection points are often much too close together and chemical precipitation can therefore occur. 

Acid can be injected into a flow assembly, but not to the same unit housing any other monitoring device, or other chemical injection port. An alternative is to add acid directly into a forebay, or the cooling tower sump (at a point of rapid mixing, but away from the pump suction, or chlorine/bromine discharge point, or bleed valve). 

Where bromine feeders are employed, never install the bromine water discharge close to any acid, inhibitor chemical injection point, or area where corrosion can result. Bromine injection points should be at least 6 ft (2 m) away from any other inhibitor to prevent inhibitor oxidation. Despite what literature may say, if bromine water containing 80 to 200 ppm or more of Br is injected close to an inhibitor chemical, some breakdown of the inhibitor will occur ... 

Piping areas just downstream of a corrosive chemical injection point should receive particular examination. 

Cost of package boiler plants. Price includes complete boiler, feed-water deaerator, boiler feed pumps, chemical injection system, stack, and shop assembly labor. 

---