Plant output

Using a chemical plant to its highest efficiency and occupancy is common-sense economics. The role of R D in this activity is to produce processes that are highly efficient, both in the utilisation of the chemical materials involved in the process and in the capital items that constitute the manufacturing plant. 

The identification of the fall off in plant output uses the same statistical process control methods as for product quality [D-4]. Usually, and certainly in the larger manufacturing units, these issues will be handled by the local plant support teams. However, sometimes output issues arise which are outside the more routine evolutionary techniques employed by the process control teams. A typical example is when the output from a process is constrained by a particular plant item. An improved piece of equipment needs to be identified and evaluated. The introduction of this equipment will usually necessitate process changes for maximum efficiency. This and similar packages of work are best done by an R D project team. 

When the sales of a product are projected to reach levels beyond the capacity of the existing plant, consideration must be given to the construction of a larger one. This is an opportunity for R D to carry out a thorough re-examination of the total process and the necessary plant, prior to the design and construction of the new plant. This 

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Many large petrochemical projects involve considerable investment. Plant output value can be measured in staggering amounts of money if value of lost production is calculated. An incorrect pressure switch installed on a compressor may have very little direct financial impact to a compressor manufacturer, but it can cause a loss to the user far in excess of the total value of the compressor package itself. Extra care must therefore be taken in compressor performance tests. In the planning of a pro- ject, testing has to be reviewed to ... 

It is conventional to refer to the system being controlled as the plant, and this, as with other elements, is represented by a block diagram. Some inputs, the engineer will have direct control over, and can be used to control the plant outputs. These are known as control inputs. There are other inputs over which the engineer has no control, and these will tend to deflect the plant outputs from their desired values. These are called disturbance inputs. 

For land-based gas turbines, the overall plant output, efficiency, emissions, and reliability are the important variables. In a gas turbine, the processes of compression, combustion, and expansion do not occur in a single component, as they do in a diesel engine. They occur in components that can be developed separately. Therefore, other technologies and components can be added as needed to the basic components, or entirely new components can be substituted. 

Figure 7.3 (a) Model of manning requirements related to plant output (b) Sankey diagram of the changing manning requirement in an expanding plant... 

Two-position detectors such as thermostats can be fitted with an anticipatory bias to reduce the amount of overshoot. In such instruments, a small bias heater accelerates the action of the control. An alternative method to reduce overshoot is to introduce a timing device so that it acts intermittently. Where the two-position sensor is also the controller it provides only two plant outputs, maximum or zero. 

The manipulated variable is the variable of the process acted upon to maintain the plant output (controlled variable) at the desired value. 

Hydrogen as well as syngas may also be used to power a combined cycle plant. The plant output can be adjusted to generate more power or more hydrogen as needed. 

Most economic evaluations of the saccharification process (21,22,23) conclude that at the present time the cost of production of the most favoured products (glucose, single cell protein, ethanol) is higher than production from non-cellulosic sources. Nyiri (24) made an economic evaluation of cellulose-based single cell protein and ethanol production. He suggested that an economical plant output is between 7 and 20 m /year, and, depending on the size and complexity of the plant, estimated capital costs between 6 and 12 million. 

To increase the value of the demonstration plant, features have been incorporated to permit operation under other than demonstration conditions. It will be possible to operate the evaporator at first-effect temperatures up to 300° F., thus almost doubling plant output if calcium sulfate scale can be prevented, and to use the acid method of scale prevention in place of the sludge method. Provisions have been made for later installation of a vapor compressor, which would convert the plant to a combination multiple effect-thermocompression system. This would add about 15% to plant output and would permit performance evaluation of vapor compressors in sea water service. 

In this section we collect some computed results when simulating industrial steam reformers. We compare the actual plant outputs with those obtained by simulation using the three models that we have developed earlier. We investigate both the close to thermodynamic equilibrium case and the far from thermodynamic equilibrium case. 

However, site services and infrastructure are not only a major driver of cost competitiveness. Some of the services are also crucial for improving plant effectiveness. Maintenance performance, for instance, can have a huge impact on plant output. Unplanned breakdowns, often caused by failure to implement the most effective maintenance strategy or by poor execution, can lead to as much as a 20 percent loss in overall equipment effectiveness (OEE see also Chapter 18). On the utilities side, significant cost advantages can be captured, e.g., by providing... 

Allowance allocation plant closure biased towards higher emitting plant output (and consumption) from average carbon biased towards higher emitting plant incentives for energy efficiency investments... 

Innovative process designs are being developed to reduce the size of the membrane unit and the energy needed to separate, condense and inject the carbon dioxide. It seems possible to reduce the energy consumption of the membrane process to about 20-25% of the power plant output. If this work is successful and these membrane plants are built, this application will dwarf all other gas-separation membrane processes. 

In some cases, taking the opposite approach, using slower solvating, higher molecular weight and less efficient phthalates, such as DINP and DIDP, has been shown to increase plant output in certain calendering and extrusion operations. Table II compares results of a wire insulation extrusion study with DOP vs. DINP. 

Improving existing products and increasing plant output is very cost efficient work for RtS D. 

As plant outputs, we may notice cyclohexanone or KA-oil, with small liquid bleeds in lights and heavies, but no hazardous or greenhouse gas emissions. 

Natural gas is the main source of hydrogen. See Barclay (1998) for details of an early ICI large natural gas reform plant, outputting hydrogen and methanol. Balanced marketing of both hydrogen and methanol from such a plant or a modern Canadian equivalent (Methanex Inc. see web site) would be needed. The DMFC is therefore a potentially important, but relatively immature, type of PEFC, and, logically, Ballard and Johnson Matthey are active in that area. 

The main plant output from fuel chemical exergy would be a function of the amount of fuel isothermally oxidised in the fuel cell, with a minority contribution from the calorific value of the fuel burnt in the... 

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