CN1334313A

CN1334313A - Adsorption-absorption process for recovering oil gas

Info

Publication number: CN1334313A
Application number: CN 00118594
Authority: CN
Inventors: 张国瑞; 邱孟杰
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-07-13
Filing date: 2000-07-13
Publication date: 2002-02-06

Abstract

An absorption-adsorption process for recovering oil gas is disclosed. Its advantages are high throughout, whide application range, low-concentration exhaust, low temp of "heat point" and less investment.

Description

A kind of technical process that absorbs adsorption combined recovery oil gas

The present invention relates to a kind of technical process that adsorption combined reclaims oil gas that absorbs.

In the storage and transport process of light-end products (as gasoline, kerosene, crude oil, benzene, ethanol etc.), want some oil gas volatilization to enter atmosphere inevitably, thereby generation is polluted, cause waste, and influence safety in production, in recent decades, people have invented a lot of technology reclaiming this part oil gas, and absorption process and absorption method are two kinds of methods commonly used wherein.

These two kinds of technologies all are made up of two portions substantially.Forebody is the gas-oil separation part, realizes oil gas and air separation are opened, and latter half of is enrichment oil gas recovery part, realizes gaseous state enrichment oil gas liquefy Oil Recovery.The key distinction of two kinds of technologies is first half.The ultimate principle of absorption process is, with a kind of absorption agent and oil laden air counter current contact in the absorption tower that oil gas is had better receptivity, oil gas is absorbed, the air of removing oil gas enters atmosphere, absorbed the rich absorbent desorb under negative pressure again of oil gas, oil gas is wherein desorbed, and then this part enrichment oil gas is reclaimed again by the method for condensation or absorption.The ultimate principle of absorption method is, utilize oil gas and air on sorbent material, to adsorb different with desorption rate, select a kind of sorbent material (as gac) with bigger serface, oil gas in the oil-containing gases is absorbed, the air of removing oil gas enters atmosphere, the sorbent material that has adsorbed a certain amount of oil gas is desorption under negative pressure again, the enrichment oil gas that desorption comes out, and the method by condensation or absorption is recovered equally.

As the oil gas recovery technology, more than two kinds of technologies relative merits are respectively arranged.

The advantage of absorption process is, flow process is fairly simple, and when high throughput, facility investment is relatively low, and control requires lowlyer, applied widely automatically, and turndown ratio is big, serviceability.Its maximum shortcoming is, absorbs the air hydrocarbon content height that discharge the back, and generally, the gas concentration in the discharged air is about 80mg/L, and this index is much higher than the present emission standard of western developed country, as U.S.'s emission standard for being not more than 10mg/L.Therefore, at present this technology in the less employing of western developed country.The advantage that absorption method is outstanding is, the hydrocarbon content of absorption back discharged air is low, and theoretically, as long as quantity of sorbent is abundant, the hydrocarbon content in the discharged air can be infinitely low, but consider the factor of investment, is controlled at usually and is not more than 10mg/L.Its shortcoming is, facility investment is relatively large during big the processing, and control is had relatively high expectations automatically, when olefin(e) centent is high, the easy coking and deactivation of life-time service sorbent material, when gas concentration is high,, cause adsorbent bed temperature rise bigger because oil gas is emitted a large amount of heats in adsorption process, at adsorbent bed local form " focus ", the danger of sorbent material spontaneous combustion is arranged, therefore, the sorbent material spontaneous ignition temperature is had relatively high expectations.

The present invention proposes a kind of absorption adsorption combined technology flow process.

Oil-containing gases from storage and transport process, at first pass through solvent absorbing, about oil gas of about 85% is wherein absorbed, residual gas carries out adsorbents adsorb again, be less than the 10mg/L level through absorbing and adsorb the airborne oily concentration that two processes discharge, owing to absorb and the regeneration of adsorbing two processes is negative pressure regeneration, and regeneration pressure is close, by suitable pressure control circuit control, can realize shared vacuum pump operation.

This combination process is particularly suitable for high throughput oil gas and reclaims loading amount.Absorption process has reclaimed about 85% oil gas with relatively low investment, this process has bigger turndown ratio to the variation of oil gas load and concentration, when the operation operating mode was stablized, no matter how oily concentration changes in the air inlet, the concentration of discharging gas was stable basically.The lower concentration (the about 80mg/L of oily concentration) of discharging from absorption process, the metastable oil-containing gases of concentration, when passing through adsorbents adsorb again, sorbent material consumption and equipment size significantly reduce, thereby have reduced plant investment relatively.Greatly reduce owing to enter the gas concentration of adsorption process, the adsorption process thermal discharge reduces greatly, and " focus " temperature reduces greatly, and the process security improves, and the oily concentration in the final discharged air can be less than the 10mg/L level.

Figure the-1st, the present invention are used for the schematic flow sheet of the oil gas recovery of light-end products entrucking process.

When light-end products were packed tank car (1) into from pipeline (21), the oil-containing gases of formation at first entered the absorption portion that oil gas reclaims loading amount by tank car closed loading system.(2) bottom enters and poor absorption agent counter current contact on filler of getting off from cat head oil gas from the absorption tower, and wherein oil gas is absorbed.The rich absorbent that has absorbed oil gas at the bottom of tower Liquid level adjusting valve (11) by separating cucurbitula (3) into negative-pressure operation from compressing into, desorbed at this oil gas, enter latter half enrichment gas recovery system for oil, poor absorption agent after the desorb is returned top, absorption tower (2) again through poor absorption agent pump (4) and is refluxed, and forms to absorb desorption cycle.(2) eject next gas from the absorption tower, wherein contain the oil gas of the 80mg/L that has an appointment, and the adsorption tanks (9) and the adsorption tanks (10) that enter two mutual blocked operations of absorbed portion again carry out the adsorption/desorption operation.Adsorption tanks (9) are when adsorbing, and adsorption tanks (10) carry out desorption, and at this moment, valve (15), (16), (20) are in opened condition, and valve (17), (18), (19) are in closing condition.Be less than 10mg/L through oily concentration in the air of adsorbent bed absorption, enter atmosphere through relief outlet (22).Behind adsorption operations after a while, sorbent material is saturated near absorption, at this moment open automatically valve (17), (18), (19), valve (15), (16), (20) are closed automatically, adsorption tanks (10) enter adsorption operation condition, adsorption tanks (9) enter the desorption manipulation state, and absorption and desorption process so circulate.Because desorb and two processes of desorption are all finished under negative pressure, negative pressure is provided by same vacuum pump (5), logic control is carried out according to vacuum pump (5) inlet pressure respectively in two variable valve (12) and (13), the transformation operation that realizes vacuum pump (5) inlet pressure, separates the stable and adsorption tanks (10) of cucurbitula (3) pressure.

The enrichment oil gas that desorb and desorption come out is sent into latter half enrichment oil gas recovery part after being boosted by vacuum pump (5).At this, enrichment oil gas enters catch pot (7) after condenser (6) condensation cooling, and uncondensed gas turns back to absorption tower (2) and absorbs, and the oil product that condenses is sent back to the storing and transporting system from egress line (23) by Liquid level adjusting valve (14).Enrichment oil gas reclaims and also can adopt light-end products to make absorption agent directly enrichment oil gas to be absorbed, send back to the flow process of going in the storing and transporting system then.

Claims

1. absorption and adsorption combined reclaim the technical process of oil gas, reclaiming two portions by gas-oil separation and enrichment oil gas forms, it is characterized in that: the gas-oil separation part is formed by absorbing and adsorbing two technological processs, the negative pressure of desorb and desorption is provided by vacuum pump (5), and the working pressure of desorb and desorption is regulated control by a pressure control circuit that is made of two groups of variable valve (12) and (13).

2. flow process according to claim 1 is characterized in that: oil-containing gases reclaims most of oil gas by absorption process earlier, realizes the gaseous emission of low oily concentration again through adsorption process.

3. flow process according to claim 1 is characterized in that: the negative pressure of desorb and desorption is provided by same group of vacuum pump (5).

4. flow process according to claim 1 is characterized in that: realize regulating control by the pressure control circuit that two groups of variable valve (12) and (13) constitute by logic control.